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Sample records for acetonitrile

  1. Detection of adulteration in acetonitrile

    Chen, Guoxiang; Fujimori, Kiyoshi; Lee, Hans; Nashed-Samuel, Yasser; Phillips, Joseph; Rogers, Gary; Shen, Hong; Yee, Chanel

    2011-05-01

    To address the increasing concern that acetonitrile may be intentionally adulterated to meet the shortfall in global supplies resulting from a downturn in its manufacturing, three analytical techniques were examined in this study. Gas Chromatography with Thermal Conductivity Detection (GC-TCD), Near Infrared (NIR) spectroscopy and Fourier Transform Infrared (FT-IR) spectroscopy were assessed for their ability to detect and quantify potential adulterants including water, alternative organic solvents, and by-products associated with the production of acetonitrile. The results of the assessment of the three techniques for acetonitrile adulteration testing are discussed.

  2. Tungsten acetonitrile complexes, containing nitrosyl ligand

    Synthesized are tungsten acetonitrile derivatives, containing nitrosyl ligand. In a course of boiling W(CO)4(NO)I-(1) at the excess of acetonitrile there is formed bis-(acetonitrile)-dicarbonilenitrosyltungsteniod-(2): W(CO)4(NO)I+2CH3CN → 2CO+(CH3CN)2W(CO)2(NO)I-(2). Investigation in reactionary ability of compound (2) is carried out. It is shown that at the reaction of acetonitrile complex (2) with two equivalents of triphenylphosphine depending on reaction conditions formed is a number of products

  3. Bromidotris(triphenylphosphanesilver acetonitrile monosolvate monohydrate

    Anita M. Owczarzak

    2011-11-01

    Full Text Available In the title compound, [AgBr(C18H15P3]·C2H3N·H2O, the coordination of the Ag atom is close to ideal tetrahedral, with the three Ag—P bond lengths almost equal [2.5441 (10, 2.5523 (9 and 2.5647 (10 ° A] and the Ag—Br bond slightly longer [2.7242 (5 Å]. The coordination tetrahedron is slightly flattened, the Ag atom is closer to the PPP plane; the P—Ag—P angles are wider than the Br—Ag—P angles. The voids in the crystal structure are filled with ordered acetonitrile solvent molecules. The remaining electron density was interpreted as a water molecule, disordered over three alternative positions. Neither of the solvent molecules is connected by any directional specific interactions with the complex.

  4. Pyridinolysis of Dipropyl Chlorophosphate in Acetonitrile

    Hoque, Md. Ehtesham Ul; Lee, Hai Whang [Inha Univ., Incheon (Korea, Republic of)

    2012-10-15

    Continuing the kinetic studies on the pyridinolyses of dimethyl [1: (MeO){sub 2}P(=O)Cl], diethyl [2: (EtO){sub 2}P(=O)Cl],1a dibutyl [4: (BuO){sub 2}P(=O)Cl], diisopropyl [5: (i-PrO){sub 2}P(=O) Cl], and Y-aryl phenyl [6: (PhO)(YC{sub 6}H{sub 4}O) P(=O)Cl] chlorophosphates, the nucleophilic substitution reactions of dipropyl chlorophosphate (3) with X-pyridines are investigated kinetically in acetonitrile (MeCN) at 35.0 ± 0.1 .deg. C (Scheme 1). The aim of this work is to gain further information into the reactivity and mechanism depending on the variation of the two ligands, R{sub 1}O and R{sub 2}O. The numbering of the substrates of 1-6 follows the sequence of the summation of the Taft steric constants of the two ligands, R{sub 1} and R{sub 2}: 6(PhO,YC{sub 6}H{sub 4}O) > 5(i-PrO){sub 2} > 4(BuO){sub 2} > 3(PrO){sub 2} > 2(EtO){sub 2} > 1(MeO){sub 2}.

  5. Hexakis(acetonitrile-κNruthenium(II bis(hexabromocarbadodecaborate acetonitrile solvate

    Anna Larsen

    2010-03-01

    Full Text Available The title compound, [Ru(NCCH36](CH6B11Br62·CH3CN, consists of the 'naked' ruthenium(II cation surrounded by six acetonitrile molecules, each coordinated via the nitrogen atoms in a linear or nearly-linear fashion in a typical octahedral over-all arrangement. The cation is balanced by the two hexa-bromocarborane cage anionic fragments [CB11H6Br6]. Weak C—H...Br and B—H...Br interactions link neighboring anions.

  6. Tris(acetonitrile-κNdichlorido(triphenylphosphane-κPruthenium(II acetonitrile monosolvate

    Xiao-Feng Yin

    2013-06-01

    Full Text Available In the title complex, [RuCl2(CH3CN3(C18H15P]·CH3CN, the coordination geometry of the RuII atom is distorted octahedral, defined by one P atom from a triphenylphosphane ligand, three N atoms from three acetonitrile ligands and two Cl atoms. The three acetronitile ligands linearly bind to the RuII atom, with Ru—N—C angles of 172.6 (2, 179.9 (2 and 171.4 (2°.

  7. Bis(acetonitrile-κNdichlorido(η4-cycloocta-1,5-dieneruthenium(II acetonitrile monosolvate

    Haleden Chiririwa

    2011-08-01

    Full Text Available In the title RuII complex, [RuCl2(C8H12(C2H3N2]·CH3CN, the metal ion is coordinated to the centers of each of the double bonds of the cyclooctadiene ligand, to two chloride ions (in cis positions and to two N-atom donors (from MeCN molecules that complete the coordination sphere for the neutral complex. The coordination about the RuII atom can thus be considered to be octahedral with a slightly trigonal distortion. There is also one acetonitrile solvent molecule per molecule which is outside the coordination sphere of the ruthenium atom.

  8. Inhalation developmental toxicology studies: Acetonitrile in rats. Final report

    Mast, T.J.; Weigel, R.J.; Westerberg, R.B.; Boyd, P.J.; Hayden, B.K.; Evanoff, J.J.; Rommereim, R.L.

    1994-02-01

    The potential for acetonitrile to cause developmental toxicity was assessed in Sprague-Dawley rats exposed to 0, 100, 400, or 1200 ppM acetonitrile, 6 hours/day, 7 days/week. Exposure of rats to these concentrations of acetonitrile resulted in mortality in the 1200 ppM group (2/33 pregnant females; 1/10 non-pregnant females). However, there were no treatment-related effects upon body weights or reproduction indices at any exposure level, nor was there a significant increase in the incidence of fetal malformations or variations. The only effect observed in the fetuses was a slight, but not statiscally significant, exposure-correlated increase in the incidence of supernumerary ribs. Determination of acetonitrile and cyanide concentrations in maternal rat blood showed that acetonitrile concentration in the blood increased with exposure concentration for all exposed maternal rats. Detectable amounts of cyanide in the blood were found only in the rats exposed to 1200 ppM acetonitrile ({approximately}2 {mu}g cyanide/g of blood).

  9. Studies on the mechanism of acetonitrile toxicity 1

    Male ICR mice were given a tracer dose of 2-14C-acetonitrile intravenously (60 μ mol/kg or 684 μCi/kg, spec. act. 11.4 mCi/mmol). At various time intervals (5 min., 0.5, 1, 4, 8, 24 and 48 hr) after treatment, mice were anaesthetized and frozen by immersion in a dry ice/hexane mixture, or they were dissected for collection of organs and tissues. Frozen mice were processed for whole body autoradiography, which allows the detection of non-volatile metabolites of acetonitrile at their sites of accumulation. Covalent binding of acetonitrile metabolites in tissues was determined using trichloroacetic acid followed by ethanol/ether extraction techniques. Whole body autoradiography revealed heavy localization of acetonitrile metabolites in the gastrointestinal tissues and bile. At 5 min., the highest levels of radioactivity occurred in the liver and kidney; levels declined over time. At 24 and 48 hr, acetonitrile derived radioactivity were detected in the gastrointestine, thymus, liver and male reproductive organs. Covalent binding studies at 24 and 48 hr after treatment indicated that 40-50% of the total radioactivity present in the liver was bound to the macromolecular fractions of the tissues. The radioactivity contents of other organs were, in large part (40-50% of total), present in the lipid fraction of the tissue. Our studies suggest that the irreversible association with tissus of radioactivity derived from 2-14C-acetonitrile is due to the metabolic activation of acetonitrile and the covalent interaction of reactive metabolite(s) with lipid and macromolecular fractions of the cell. (BN)

  10. Trace level detection of europium using luminescence in acetonitrile medium

    Trace level determination of lanthanides is very important in various fields such as environmental sciences, nuclear industry and forensic sciences. Ligand sensitized luminescence has been widely used for trace and ultra trace determination of these metal ions in various samples. Luminescence of lanthanides is highly tender towards -OH oscillators which makes it difficult for ultra trace determination and requires some complexing agents to remove water molecules from the inner coordinated sphere. In order to avoid quenching from water molecules, in the study authors have tried different non aqueous organic solvents and acetonitrile was found to be good for luminescence study. Luminescence from Eu3+ complexed with benzoic acid (BA) has been studied using acetonitrile as a solvent. More than two orders of luminescence enhancement is found in acetonitrile medium compared to Eu3+-BA complex in aqueous medium. In contrary to aqueous medium where Eu3+-BA forms ML and ML2 type species, spectroscopic data reveal formation of only ML3 complex in MeCN medium. Large ratio of 5D0-7F2 to 5D0-7F1 transitions (asymmetric ratio) in luminescence spectra of europium benzoate suggested the different site symmetry in acetonitrile. UV-Vis spectroscopy along with luminescence spectroscopy was utilized to obtain the structure and stoichiometry of the complex. HypSpec computation program was used for calculating stability constants for the complex formed in acetonitrile. Linearity in the luminescence intensity is seen over the Eu3+ concentration range of 5 x 10-9 to 1 x 10-5 M and the detection limit calculated using the criterion of 3σ is 3 x 10-10 M

  11. (Acetonitrile[bis(2-pyridylmethylamine]bis(perchloratocopper(II

    Ray J. Butcher

    2008-01-01

    Full Text Available In the title compound, [Cu(ClO42(C12H13N3(C2H3N], the CuII atom is six-coordinate in a Jahn–Teller distorted octahedral geometry, with coordination by the tridentate chelating ligand, an acetonitrile molecule, and two axial perchlorate anions. The tridentate ligand bis(2-pyridylmethylamine chelates meridionally and equatorially while an acetonitrile molecule is coordinated at the fourth equatorial site. The two perchlorate anions are disordered with site occupancy factors of 0.72/0.28. The amine H is involved in intramolecular hydrogen bonding to the perchlorate O atoms and there are extensive but weak intermolecular C—H...O interactions.

  12. Determination of Acetonitrile Volume Fraction in Mobile Phase by HPLC

    WU Yi; WANG Zhi-wu; GU Jing-kai; WANG Ying-wu

    2008-01-01

    This paper reports the development and validation of an assay for the determination of acetonitrile in the recycled mobile phase using high performance liquid chromatography(HPLC).The method is based on that the retention in reversed-phase liquid chromatography increases with decreasing concentration of organic phase in the mobile phase.The natural logarithm of the capacity ratio for a given solute is linearly related to the volume fraction of the organic modifier in the mobile phase.For dimethylphthalate and diethylphthalate,the linearity range is 30%--60%,and for biphenyl and terphenyl,the range is 60%-95%.Precision values(RSD) were both <1% and the accuracy(RE) was in the range of ±1%.The assay was successfully applied to the determination of acetonitrile concentration of recycled mobile phase after the distillation of the column eluent in our laboratory.

  13. Photophysics of Diphenylbutadiynes in Water, Acetonitrile-Water, and Acetonitrile Solvent Systems: Application to Single Component White Light Emission.

    Pati, Avik Kumar; Jana, Rounak; Gharpure, Santosh J; Mishra, Ashok K

    2016-07-28

    Diacetylenes have been the subject of current research because of their interesting optoelectronic properties. Herein, we report that substituted diphenylbutadiynes exhibit locally excited (LE) and excimer emissions in water and multiple emissions from the LE, excimer, and intramolecular charge transfer (ICT) states in acetonitrile-water solvent systems. The LE, excimer, and ICT emissions are clearly distinguishable for a diphenylbutadiynyl derivative with push (-NMe2)-pull (-CN) substituents and those are closely overlapped for non-push-pull analogues. In neat acetonitrile, the excimer emission disappears and the LE and ICT emissions predominate. In the case of the push (-NMe2)-pull (-CN) diphenylbutadiyne, the intensity of the ICT emission increases with increasing the fluorophore concentration. This suggests that the ICT emission accompanies with intermolecular CT emission which is of exciplex type. As the LE and exciplex emissions of the push-pull diphenylbutadiyne together cover the visible region (400-700 nm) in acetonitrile, a control of the fluorophore concentration makes the relative intensities of the LE and exciplex emissions such that pure white light emission is achieved. The white light emission is not observed in those diphenylbutadiynyl analogues in which the peripheral substituents of the phenyl rings do not possess strong push-pull character. PMID:27379734

  14. Catalysis of water oxidation in acetonitrile by iridium oxide nanoparticles

    Hidalgo-Acosta, Jonnathan C.; Méndez, Manuel A.; Scanlon, Micheál D.; Vrubel, Heron; Amstutz, Véronique; Adamiak, Wojciech; Opallo, Marcin; Girault, Hubert H.

    2015-01-01

    Water oxidation catalysed by iridium oxide nanoparticles (IrO2 NPs) in water–acetonitrile mixtures using [RuIII(bpy)3]3+ as oxidant was studied as a function of the water content, the acidity of the reaction media and the catalyst concentration. It was observed that under acidic conditions (HClO4) and at high water contents (80% (v/v)) the reaction is slow, but its rate increases as the water content decreases, reaching a maximum at approximately equimolar proportions (≈25% H2O (v/v)). The re...

  15. 2-(Pyridin-2-ylamino)pyridinium thiocyanate acetonitrile monosolvate

    Bonell Schmitt; Thomas Gerber; Eric Hosten; Richard Betz

    2011-01-01

    The title compound, C10H10N3+·NCS−·CH3CN, is the acetonitrile solvate of the thiocyanate salt of protonated dipyridin-2-ylamine. Protonation occurs at one of the pyridine N atoms. The molecular geometry around the central N atom is essentially planar (sum of angles = 359.89°). In the crystal, N—H...N hydrogen bonds, as well as C—H...S contacts link the different residues into chains along the c-axis direction. Interaction between aromat...

  16. Luminescence enhancement of uranyl ion by benzoic acid in acetonitrile

    Uranyl ion is known for its characteristic green luminescence and therefore luminescence spectroscopy is a suitable technique for characterizing different uranyl species. In aqueous medium, luminescence of uranyl ion is generally weak due to its quenching by water molecules and therefore in order to enhance the luminescence of uranyl ion in aqueous medium, luminescence enhancing reagents such as H3PO4, H2SO4, HCIO4 have been widely used. The other method to enhance the uranyl luminescence is by ligand sensitized luminescence, a method well established for lanthanides. In this work, luminescence of uranyl ion is found to be enhanced by benzoic acid in acetonitrile medium. In aqueous medium benzoic acid does not enhance the uranyl luminescence although it forms 1:1 and 1:2 complexes with uranyl ion. Luminescence spectra of uranyl benzoate revealed that enhancement is due to sensitization of uranyl luminescence by benzoate ions. UV-Vis spectroscopy has been utilized to characterize the specie formed in the in acetonitrile medium. UV-Vis spectroscopy along with luminescence spectra revealed that the specie to be tribenzoate complex of uranyl (UO2 (C6H5COO)3)- having D3h symmetry. (author)

  17. Thermodynamics of the Solvation and phase distributions of ethylenediamine in acetonitrile-dimethylsulfoxide-hexane systems

    Semenov, I. M.; Repkin, G. I.; Sharnin, V. A.

    2013-03-01

    The enthalpies of dissolution and solvation of ethylenediamine over the range of compositions of a mixed acetonitrile-dimethylsulfoxide solvent at 298 K are determined calorimetrically. It is found that with an increase in the acetonitrile concentration, the solvation exothermicity of ethylenediamine declines, owing to the resolvation of amino groups. The Gibbs energies of transfer of ethylenediamine from dimethylsulfoxide into its mixtures with acetonitrile are determined from the distribution of a substance between immiscible phases. It is found that increasing the acetonitrile concentration in a binary solvent improves the stability of the ethylenediamine solvatocomplex, owing to a change in the entropy component of the Gibbs energy.

  18. Structure of human insulin monomer in water/acetonitrile solution

    Bocian, Wojciech; Sitkowski, Jerzy; Bednarek, Elzbieta [National Medicines Institute (Poland); Tarnowska, Anna; Kawecki, Robert [Institute of Organic Chemistry Polish Academy of Sciences (Poland); Kozerski, Lech [National Medicines Institute (Poland)], E-mail: lkoz@icho.edu.pl

    2008-01-15

    Here we present evidence that in water/acetonitrile solvent detailed structural and dynamic information can be obtained for important proteins that are naturally present as oligomers under native conditions. An NMR-derived human insulin monomer structure in H{sub 2}O/CD{sub 3}CN, 65/35 vol%, pH 3.6 is presented and compared with the available X-ray structure of a monomer that forms part of a hexamer (Acta Crystallogr. 2003 Sec. D59, 474) and with NMR structures in water and organic cosolvent. Detailed analysis using PFGSE NMR, temperature-dependent NMR, dilution experiments and CSI proves that the structure is monomeric in the concentration and temperature ranges 0.1-3 mM and 10-30 deg. C, respectively. The presence of long-range interstrand NOEs, as found in the crystal structure of the monomer, provides the evidence for conservation of the tertiary structure. Starting from structures calculated by the program CYANA, two different molecular dynamics simulated annealing refinement protocols were applied, either using the program AMBER in vacuum (AMBER{sub V}C), or including a generalized Born solvent model (AMBER{sub G}B)

  19. Structure of human insulin monomer in water/acetonitrile solution

    Here we present evidence that in water/acetonitrile solvent detailed structural and dynamic information can be obtained for important proteins that are naturally present as oligomers under native conditions. An NMR-derived human insulin monomer structure in H2O/CD3CN, 65/35 vol%, pH 3.6 is presented and compared with the available X-ray structure of a monomer that forms part of a hexamer (Acta Crystallogr. 2003 Sec. D59, 474) and with NMR structures in water and organic cosolvent. Detailed analysis using PFGSE NMR, temperature-dependent NMR, dilution experiments and CSI proves that the structure is monomeric in the concentration and temperature ranges 0.1-3 mM and 10-30 deg. C, respectively. The presence of long-range interstrand NOEs, as found in the crystal structure of the monomer, provides the evidence for conservation of the tertiary structure. Starting from structures calculated by the program CYANA, two different molecular dynamics simulated annealing refinement protocols were applied, either using the program AMBER in vacuum (AMBERVC), or including a generalized Born solvent model (AMBERGB)

  20. Interaction of acetonitrile with thin films of solid water

    Thin films of water were prepared on Ag at 124 K. Their properties were studied with metastable impact electron spectroscopy, reflection absorption infrared spectroscopy, and temperature programmed desorption. The interaction of acetonitrile (ACN) with these films was studied with the abovementioned techniques. From the absence of any infrared activity in the initial adsorption stage, it is concluded that ACN adsorbs linearly and that the C≡N axis is aligned parallel to the water surface (as also found on neat Ag). Initially, the interaction with water surface species involves their dangling OD groups. During the completion of the first adlayer the ACN-ACN lateral interaction becomes of importance as well, and the ACN molecules become tilted with respect to the water surface. ACN shows propensity to stay at the surface after surface adsorption even during annealing up to the onset of desorption. The present results for the ACN-water interaction are compared with available classical molecular dynamics calculations providing the orientation profile for ACN on water as well as the ACN bonding properties.

  1. Lithium solvation in dimethyl sulfoxide-acetonitrile mixtures

    Semino, Rocío; Zaldívar, Gervasio; Calvo, Ernesto J. [Departamento de Química Inorgánica Analítica y Química-Física e INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, 1428 Buenos Aires (Argentina); Laria, Daniel, E-mail: dhlaria@cnea.gov.ar [Departamento de Química Inorgánica Analítica y Química-Física e INQUIMAE, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pabellón II, 1428 Buenos Aires (Argentina); Departamento de Física de la Materia Condensada, Comisión Nacional de Energía Atómica, Avenida Libertador 8250, 1429 Buenos Aires (Argentina)

    2014-12-07

    We present molecular dynamics simulation results pertaining to the solvation of Li{sup +} in dimethyl sulfoxide-acetonitrile binary mixtures. The results are potentially relevant in the design of Li-air batteries that rely on aprotic mixtures as solvent media. To analyze effects derived from differences in ionic size and charge sign, the solvation of Li{sup +} is compared to the ones observed for infinitely diluted K{sup +} and Cl{sup −} species, in similar solutions. At all compositions, the cations are preferentially solvated by dimethyl sulfoxide. Contrasting, the first solvation shell of Cl{sup −} shows a gradual modification in its composition, which varies linearly with the global concentrations of the two solvents in the mixtures. Moreover, the energetics of the solvation, described in terms of the corresponding solute-solvent coupling, presents a clear non-ideal concentration dependence. Similar nonlinear trends were found for the stabilization of different ionic species in solution, compared to the ones exhibited by their electrically neutral counterparts. These tendencies account for the characteristics of the free energy associated to the stabilization of Li{sup +}Cl{sup −}, contact-ion-pairs in these solutions. Ionic transport is also analyzed. Dynamical results show concentration trends similar to those recently obtained from direct experimental measurements.

  2. Lithium solvation in dimethyl sulfoxide-acetonitrile mixtures

    We present molecular dynamics simulation results pertaining to the solvation of Li+ in dimethyl sulfoxide-acetonitrile binary mixtures. The results are potentially relevant in the design of Li-air batteries that rely on aprotic mixtures as solvent media. To analyze effects derived from differences in ionic size and charge sign, the solvation of Li+ is compared to the ones observed for infinitely diluted K+ and Cl− species, in similar solutions. At all compositions, the cations are preferentially solvated by dimethyl sulfoxide. Contrasting, the first solvation shell of Cl− shows a gradual modification in its composition, which varies linearly with the global concentrations of the two solvents in the mixtures. Moreover, the energetics of the solvation, described in terms of the corresponding solute-solvent coupling, presents a clear non-ideal concentration dependence. Similar nonlinear trends were found for the stabilization of different ionic species in solution, compared to the ones exhibited by their electrically neutral counterparts. These tendencies account for the characteristics of the free energy associated to the stabilization of Li+Cl−, contact-ion-pairs in these solutions. Ionic transport is also analyzed. Dynamical results show concentration trends similar to those recently obtained from direct experimental measurements

  3. Bromidotris(triphenyl-phosphane)silver acetonitrile monosolvate monohydrate.

    Owczarzak, Anita M; Kyros, Loukas; Hadjikakou, Sotiris K; Kubicki, Maciej

    2011-11-01

    In the title compound, [AgBr(C(18)H(15)P)(3)]·C(2)H(3)N·H(2)O, the coordination of the Ag atom is close to ideal tetra-hedral, with the three Ag-P bond lengths almost equal [2.5441 (10), 2.5523 (9) and 2.5647 (10) ° A] and the Ag-Br bond slightly longer [2.7242 (5) Å]. The coordination tetra-hedron is slightly flattened, the Ag atom is closer to the PPP plane; the P-Ag-P angles are wider than the Br-Ag-P angles. The voids in the crystal structure are filled with ordered acetonitrile solvent mol-ecules. The remaining electron density was inter-preted as a water mol-ecule, disordered over three alternative positions. Neither of the solvent mol-ecules is connected by any directional specific inter-actions with the complex. PMID:22219758

  4. Bromidotris(triphenyl­phosphane)silver acetonitrile monosolvate monohydrate

    Owczarzak, Anita M.; Kyros, Loukas; Hadjikakou, Sotiris K.; Kubicki, Maciej

    2011-01-01

    In the title compound, [AgBr(C18H15P)3]·C2H3N·H2O, the coordination of the Ag atom is close to ideal tetra­hedral, with the three Ag—P bond lengths almost equal [2.5441 (10), 2.5523 (9) and 2.5647 (10) ° A] and the Ag—Br bond slightly longer [2.7242 (5) Å]. The coordination tetra­hedron is slightly flattened, the Ag atom is closer to the PPP plane; the P—Ag—P angles are wider than the Br—Ag—P angles. The voids in the crystal structure are filled with ordered acetonitrile solvent mol­ecules. The remaining electron density was inter­preted as a water mol­ecule, disordered over three alternative positions. Neither of the solvent mol­ecules is connected by any directional specific inter­actions with the complex. PMID:22219758

  5. Laboratory investigations of irradiated acetonitrile-containing ices on an interstellar dust analog

    Abdulgalil, Ali G. M.; Marchione, Demian; Rosu-Finsen, Alexander; Collings, Mark P.; McCoustra, Martin R. S. [School of Engineering and Physical Sciences, Heriot-Watt University, Riccarton, Edinburgh, EH14 4AS (United Kingdom)

    2012-07-15

    Reflection-absorption infrared spectroscopy is used to study the impact of low-energy electron irradiation of acetonitrile-containing ices, under conditions close to those in the dense star-forming regions in the interstellar medium. Both the incident electron energy and the surface coverage were varied. The experiments reveal that solid acetonitrile is desorbed from its ultrathin solid films with a cross section of the order of 10{sup -17} cm{sup 2}. Evidence is presented for a significantly larger desorption cross section for acetonitrile molecules at the water-ice interface, similar to that previously observed for the benzene-water system.

  6. Pyridinolysis of Phenyl N-Phenyl Phosphoramido chloridate in Acetonitrile

    Hoque, Md. Ehtesham Ul; Lee, Hai Whang [Inha Univ., Incheon (Korea, Republic of)

    2012-10-15

    Kinetics and mechanism of the aminolyses for various substrates have been studied extensively by this lab. The studied substrates are dominantly (R{sub 1}O)(R{sub 2}O)P(=O or S)Cl and R{sub 1}R{sub 2}P(=O or S)Cl-type where R{sub 1} and R{sub 2} are alkyl and/or phenyl (aryl). Herein, the nucleophilic substitution reactions of phenyl N-phenyl phosphoramido chloridate (7), involving anilino (C{sub 6}H{sub 5}NH) ligand, with X-pyridines are investigated kinetically in acetonitrile (MeCN) at 35.0 ± 0.1 .deg. C (Scheme 1). The aim of this work is to gain further information into the reactivity and mechanism depending on the variation of the two ligands as well as to compare with the pyridinolyses of chlorophosphates: dimethyl [1: (MeO){sub 2}P(=O)Cl], diethyl [2: (EtO){sub 2}P(=O)Cl], dipropyl [3: (PrO){sub 2}P(=O)Cl], dibutyl [4: (BuO){sub 2}P(=O)Cl], diisopropyl [5: (i-PrO){sub 2}P(=O)Cl], and Y-aryl phenyl [6: (PhO)(YC{sub 6}H{sub 4}O)P(=O)Cl] chlorophosphates. The numbering of the substrates of 1-6 follows the sequence of the summation of the Taft steric constants of the two ligands, R{sub 1} and R{sub 2}: 6[Y = H; (PhO){sub 2}] > 5(i-PrO){sub 2} > 4(BuO){sub 2} > 3(PrO){sub 2} > 2(EtO){sub 2} > 1(MeO){sub 2} where E{sub S}(R) = .2.48(Ph); .0.47(i-Pr); .0.39(Bu); .0.36(Pr); .0.07(Et); 0.00(Me). Note that the magnitude of E{sub S}(i-Pr) is larger than that of E{sub S}(Bu) although the size of i-Pr is smaller than that of Bu. The magnitude of E{sub S}(PhNH) in 7 must be larger than that of E{sub S}(PhO) in 6. The B3LYP/6-311+G(d,p) geometries, bond angles, and natural bond order (NBO) charges of 7 in the gas phase. The MO theoretical structure shows that the two oxygens, nitrogen, and chlorine have more or less distorted tetrahedral geometry with the phosphorus atom at the center. The degree of distortion of 7 (Δδ{sub GS} = 0.36) is smaller than 6 (Δδ{sub GS} = 0.40)

  7. Detection of adulteration in acetonitrile using near infrared spectroscopy coupled with pattern recognition techniques.

    Hu, Le-Qian; Yin, Chun-Ling; Zeng, Zhi-Peng

    2015-12-01

    In this paper, near infrared spectroscopy (NIR) in cooperation with the pattern recognition techniques were used to determine the type of neat acetonitrile and the adulteration in acetonitrile. NIR spectra were collected between 400 nm and 2498 nm. The experimental data were first subjected to analysis of principal component analysis (PCA) to reveal significant differences and potential patterns between samples. Then support vector machine (SVM) were applied to develop classification models and the best parameter combination was selected by grid search. Under the best parameter combination, the classification accuracy rates of three types of neat acetonitrile reached 87.5%, and 100% for the adulteration with different concentration levels. The results showed that NIR spectroscopy combined with SVM could be utilized for determining the potential adulterants including water, ethanol, isopropyl alcohol, acrylonitrile, methanol, and by-products associated with the production of acetonitrile. PMID:26123603

  8. Mid- and long-wave infrared absorption cross sections for acetonitrile

    Infrared absorption cross sections for acetonitrile (methyl cyanide; CH3CN) have been determined in the 880-1700 cm-1 spectral region from spectra recorded using a high-resolution FTIR spectrometer (Bruker IFS 125 HR) and a multipass cell with a maximum optical pathlength of 19.3 m. Spectra of acetonitrile/dry synthetic air mixtures were recorded at 0.015 cm-1 resolution (calculated as the Bruker instrument resolution of 0.9/MOPD) at a number of temperatures between 203 and 297 K and pressures appropriate for atmospheric conditions. Intensities were calibrated using three composite acetonitrile spectra recorded at the Pacific Northwest National Laboratory. These absorption cross sections will provide an accurate basis for upper tropospheric/lower stratospheric retrievals of acetonitrile in the mid-infrared spectral region from ACE satellite data.

  9. Crystal structure of cis-anti-cis-dicyclohexane-18-crown-6 acetonitrile disolvate

    Alexander Nazarenko

    2015-07-01

    Full Text Available The title compound (systematic name: cis-anti-cis-2,5,8,15,18,21-hexaoxatricyclo[20.4.0.09,14]hexacosane acetonitrile disolvate, C20H36O6·2CH3CN, crystallizes from an acetonitrile solution of dicyclohexane-18-crown-6 on evaporation. The molecule is arranged around a center of symmetry with half the crown ether molecule and one molecule of acetonitrile symmetry independent. All O—C—C—O torsion angles are gauche while all C—O—C—C angles are trans. The sequence of torsion angles is [(tg+t(tg−t]3; the geometry of oxygen atoms is close to pseudo-D3d with three atoms below and three atoms above the mean plane, with an average deviation of ±0.16 (1 Å from the mean plane. This geometry is identical to that observed in metal ion complexes of dicyclohexane-18-crown-6 but differs significantly from the conformation of a free unsolvated molecule. Each acetonitrile molecule connects to a crown ether molecule via two of its methyl group H atoms (C—H...O. Weaker interactions exist between the third H atom of the acetonitrile methyl group and an O atom of a neighbouring crown ether molecule (C—H...O; and between the N atom of the acetonitrile molecule and a H atom of another neighbouring crown ether molecule. All these intermolecular interactions create a three-dimensional network stabilizing the disolvate.

  10. Effect of the composition of a solution on the enthalpies of solvation of piperidine in methanol-acetonitrile and dimethylsulfoxide-acetonitrile mixed solvents

    Kuz'mina, I. A.; Volkova, M. A.; Sitnikova, K. A.; Sharnin, V. A.

    2014-01-01

    Heat effects of dissolution of piperidine (ppd) are measured by calorimetry at 298.15 K over the range of composition of acetonitrile-methanol (AN-MeOH) mixed solvents. Based on the Δsol H ○(ppd)AN-MeOH values obtained using the literature data on Δsol H ○ (ppd) in acetonitrile-dimethylsulfoxide (AN-DMSO) mixed solvents and the vaporization enthalpy of ppd, the enthalpies of solvation of amine in AN-MeOH and AN-DMSO binary mixtures are calculated. A rise in the exothermicity of solvation of piperidine is observed upon the transition from AN to DMSO and MeOH, due mainly to the enhanced solvation of the amino group of ppd as a result of changes in the acid-base properties of the mixed solvent.

  11. Acetonitrile (CH3CN) infrared absorption cross sections in the 3 μm region

    High resolution infrared absorption cross sections of acetonitrile have been determined from spectra recorded in the 3 μm spectral region using a Bruker IFS 125 HR Fourier transform spectrometer (FTS) and a multipass White cell. The eleven synthetic air-broadened acetonitrile spectra were recorded at a resolution of 0.015 cm-1 (calculated as 0.9/MOPD (Maximum Optical Path Difference), the Bruker definition of resolution) over a range of different temperatures and pressures that are representative of conditions in the Earth's atmosphere (50-760 Torr and 207-296 K). Intensities were calibrated using infrared spectra recorded at the Pacific Northwest National Laboratory (PNNL). These new cross sections will enable satellite retrievals of acetonitrile in the 3 μm region from atmospheric spectra recorded by satellite instruments, such as the ACE (Atmospheric Chemistry Experiment)-FTS.

  12. A Kinetic Study on the Oxidation of Indole by Peroxomonosulphate in Acetonitrile Solvent

    Kinetics of oxidation of indole by peroxomonosulphate (PMS) in aqueous acetonitrile medium has been investigated. The reaction follows a total second order, first order each with respect to [Indole] and [PMS]. The rate of the reaction was not affected by added [H+]. Variation of ionic strength (μ) had no influence on the rate. Increase of percentage of acetonitrile decreased the rate. Absence of any polymerization indicated a nonradical pathway. Activation and thermodynamic parameters have bee n computed. A suitable kinetic scheme based on these observations is proposed. The reactivity of PMS towards Indole was found to be higher than that with peroxodisulphate

  13. Why a diaminopyrrolic tripodal receptor binds mannosides in acetonitrile but not in water?

    Diogo Vila-Viçosa

    2014-07-01

    Full Text Available Intermolecular interactions involving carbohydrates and their natural receptors play important roles in several biological processes. The development of synthetic receptors is very useful to study these recognition processes. Recently, it was synthetized a diaminopyrrolic tripodal receptor that is selective for mannosides, which are obtained from mannose, a sugar with significant relevance in living systems. However, this receptor is significantly more active in acetonitrile than in water. In this work, we performed several molecular dynamics and constant-pH molecular dynamics simulations in acetonitrile and water to evaluate the conformational space of the receptor and to understand the molecular detail of the receptor–mannoside interaction. The protonation states sampled by the receptor show that the positive charges are always as distant as possible in order to avoid large intramolecular repulsions. Moreover, the conformational space of the receptor is very similar in water above pH 4.0 and in acetonitrile. From the simulations with the mannoside, we observe that the interactions are more specific in acetonitrile (mainly hydrogen bonds than in water (mainly hydrophobic. Our results suggest that the readiness of the receptor to bind mannoside is not significantly affected in water (above pH 4.0. Probably, the hydrogen bond network that is formed in acetonitrile (which is weaker in water is the main reason for the higher activity in this solvent. This work also presents a new implementation of the stochastic titration constant-pH molecular dynamics method to a synthetic receptor of sugars and attests its ability to describe the protonation/conformation coupling in these molecules.

  14. Phase diagrams of ternary liquid system hexane-[Y(NO3)3(TBP)3]-acetonitril

    Phase diagram of ternary liquid system (TLS) hexane (1)-[Y(NO3)3(TBP)3] (2)-acetonitrile (3) is studied at T=298.15 K. Parameters of intramolecular interactions, and values of excess Gibbs energy (gE) for binary systems and TLS along the binodal curves are calculated using the data on the mutual solubility in the binary systems [Y(NO3)3(TBP)3]-hexane, hexane-acetonitrile, TLS and equations of the NTRL theory. Value gE>0 is characteristic for the investigated system, and values gE decreases in the system of pairs of (1,3), (1,2), (2,3) liquids. Algorithm of computing of binodal curves and nods for TLS within equations of the NTRL theory with the use of parameters of intramolecular interactions are presented

  15. Inhibiting effect of acetonitrile on oxygen reduction on polycrystalline pt electrode in sodium chloride solution

    Marinović Vedrana M.

    2012-01-01

    Full Text Available The oxygen reduction reaction (ORR was studied on the polycrystalline Pt electrode in 0.1 M NaCl electrolyte containing various amounts of acetonitrile (AcN. The state of the electrode surface was characterized by the cyclic voltammetry in oxygen free electrolytes, while ORR studies were performed on the polycrystalline Pt rotating disc electrode by the linear sweep voltammetry in oxygen saturated electrolytes. The acetonitrile is chemisorbed on Pt over a wide potential range, inhibiting both hydrogen adsorption and oxide formation. The extent of AcN chemisorption depends on its concentration in the solution. Initial potential of oxygen reduction is shifted negatively, while the ORR current is increasingly reduced with the increase of AcN concentration. Complete inhibition of ORR in the potential range of AcN and Cl-anion coadsorption is achieved for (0.1 M NaCl + 1 M AcN solution.

  16. Surface Induced Dissociations and Reactions of Acetonitrile Monomer, Dimer and Trimer Ions

    Mair, C.; Herman, Zdeněk; Fedor, J.; Lezius, M.; Märk, T. D.

    2003-01-01

    Roč. 118, č. 3 (2003), s. 1479-1486. ISSN 0021-9606 R&D Projects: GA ČR GA203/00/0632 Grant ostatní: Cooperation PST (AT) 2000-06 Institutional research plan: CEZ:AV0Z4040901 Keywords : surface-induced * acetonitrile monomer * trimer ions Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.950, year: 2003

  17. Ultrasonic Investigations of Molecular Interaction in Binary Mixtures of Benzyl Benzoate with Acetonitrile and Benzonitrile

    N. Jaya Madhuri; Naidu, P S; Glory, J.; K. Ravindra Prasad

    2011-01-01

    Ultrasonic velocity, density and viscosity have been measured in the binary mixtures of benzyl benzoate with acetonitrile, benzonitrile at three temperatures 30, 40 and 50 °C. From the experimental data, thermodynamic parameters like adiabatic compressibility, internal pressure, enthalpy, activation energy etc., were computed and the molecular interactions were predicted based on the variation of excess parameters in the mixture. Also theoretical evaluation of velocities was made employing th...

  18. Trypsin-Catalyzed Peptide Synthesis in Acetonitrile with Low Water Content

    YEŞİLOĞLU, Yeşim; SAĞIROĞLU, Ayten

    2002-01-01

    Trypsin was immobilized to alumina by adsorption from its aqueous solutions. The activity of trypsin was increased by immobilization for peptide synthesis. With these immobilized enzymes Bz-Arg-Leu-NH2 dipeptide synthesis was carried out. Iso amylalcohol, tetrahydrofuran and acetonitrile were used as solvents giving the highest yield in the peptide formation reaction. The yield of the peptide was strongly dependent on water content in the reaction medium. The stability of alumina-...

  19. Chemical synthesis in acetonitrile containing discharges. Insights from photoionization experiments with synchrotron radiation

    Highlights: ► Insights into the photo-induced ion chemistry of gaseous acetonitrile by VUV synchrotron radiation. ► Ionic isomer selectivity (linear vs cyclic) in the reaction of CH2CN+ with CH3CN. ► Calculations (G3 level) of structure and energetics of some relevant ionic clusters. - Abstract: The photoinduced ion chemistry of acetonitrile is investigated by using tuneable VUV synchrotron radiation in an octupolar ion guide with mass spectrometric detection. The appearance energies and yields of primary photoions and secondary ionic products deriving from self-reactions at thermal collision energies are measured. Comparison of the appearance energies of the different product ions provides insights into the reaction mechanisms. Experimental data are interpreted with the help of theoretical calculations (energies and structures at the G3 level of theory) for the various isomers of the most relevant ionic products. We find that the ion C2H2N+ is formed at the threshold with a cyclic structure, but only its linear isomer (lying 0.47 eV higher in energy) can react with acetonitrile to form CH2CNCH2+ plus HCN via a cyclic transition state.

  20. Synthesis and tribological behaviors of diamond-like carbon films by electrodeposition from solution of acetonitrile and water

    Diamond-like carbon (DLC) films were prepared on silicon substrates by liquid phase electrodeposition from a mixture of acetonitrile and deionized water. The deposition voltage was clearly reduced owing to the presence of deionized water in the electrolyte by changing the basic properties (dielectric constant and dipole moment) of the electrolyte. Raman spectra reveal that the ratio of sp3/sp2 in the DLC films is related to the concentration of acetonitrile. The surface roughness and grain morphology determined by atomic force microscopy are also influenced by the concentration of the acetonitrile. The UMT-2 universal micro-tribometer was used to test the friction properties of the DLC films obtained from electrolytes with different concentration. The results convey that the DLC film prepared from the electrolyte containing 10 vol.% acetonitrile has the better surface morphology and friction behavior comparing with the other. In addition the growth mechanism of the film was also discussed

  1. Application of Solid Phase Microextraction followed by Chromatograph-Flame Ionization Detector for Sampling and Analysis of Acetonitrile in Air

    NEMATULLAH KURD; ABDULRAHMAN BAHRAMI; FARSHID GHORBANI-SHAHNA; MAHMOUD HEIDARI

    2015-01-01

    Acetonitrile used as a solvent in manufactures and affects to central nervous system from inhalation exposure. The aim of this study was to develop a micro-solid phase extraction method for the determination of acetonitrile in the air matrix. The sampling was performed with a small diameter fused silica fiber coated with a thin film of stationary phase and was subsequently desorbed and analyzed by gas chromatograph equipped with a flame ionization detector (GC/FID). The effects of laboratory ...

  2. Surprisingly Long-Lived Ascorbyl Radicals in Acetonitrile: Concerted Proton-Electron Transfer Reactions and Thermochemistry

    Warren, Jeffrey J.; Mayer, James M.

    2008-01-01

    Proton-coupled electron transfer (PCET) reactions and thermochemistry of 5,6-isopropylidene ascorbate (iAscH−) have been examined in acetonitrile solvent.iAscH− is oxidized by 2,4,6-tBu3C6H2O• and by excess TEMPO• to give the corresponding 5,6-isopropylidene ascorbyl radical anion (iAsc•−), which persists for hours at 298 K in dry MeCN solution. The stability of iAsc•− is surprising in light of the transience of the ascorbyl radical in aqueous solutions, and is due to the lack of the protons ...

  3. Chlorido(1,3-dimethylthiourea-κSbis(triphenylphosphine-κPcopper(I acetonitrile hemisolvate

    Brian W. Skelton

    2009-08-01

    Full Text Available The title compound, [CuCl(C3H8N2S(C18H15P2]·0.5CH3CN, was prepared by the reaction of copper(I chloride with 1,3-dimethylthiourea (dmtu and triphenylphosphine (PPh3 in acetonitrile. The CuI atom has a distorted tetrahedral environment formed by two P atoms from triphenylphosphine, one S atom from the dmtu ligand and one Cl atom. In addition, the molecules exhibit intra- and intermolecular N—H...Cl interactions.

  4. On heteromolecular insertion of sulfur dioxide and acetonitrile into molybdenum-chlorine bond

    Bubbling of sulfur dioxide through MoCl5 suspension in acetonitrile enabled to perform for the first time the introduction of these ligands by Mo-Cl bonds. The addition proceeds rapidly with heat liberation at room temperature. Data of element analysis and IR-spectroscopy show, that addition product is characterized by the formula MoCl3[O2S(N = C(Me)Cl)2]MeCN. Complex of MoCl2[O2S(N = C(Me)Cl)2]MeCN composition forms during boiling. Magnetic moments testify to the fact, that these compounds are dimers

  5. 2-(Pyridin-2-yl­amino)­pyridinium thio­cyanate acetonitrile monosolvate

    Schmitt, Bonell; Gerber, Thomas; Hosten, Eric; Betz, Richard

    2011-01-01

    The title compound, C10H10N3 +·NCS−·CH3CN, is the acetonitrile solvate of the thio­cyanate salt of protonated dipyridin-2-yl­amine. Protonation occurs at one of the pyridine N atoms. The mol­ecular geometry around the central N atom is essentially planar (sum of angles = 359.89°). In the crystal, N—H⋯N hydrogen bonds, as well as C—H⋯S contacts link the different residues into chains along the c-axis direction. Inter­action between aromatic systems gives rise to π-stacking, the shortest distan...

  6. Vibrational Relaxation of the Aqueous Proton in Acetonitrile: Ultrafast Cluster Cooling and Vibrational Predissociation.

    Ottosson, N; Liu, L; Bakker, H J

    2016-07-28

    We study the ultrafast O-H stretch vibrational relaxation dynamics of protonated water clusters embedded in a matrix of deuterated acetonitrile, using polarization-resolved mid-IR femtosecond spectroscopy. The clusters are produced by mixing triflic (trifluoromethanesulfonic) acid and H2O in molar ratios of 1:1, 1:2, and 1:3, thus varying the degree of hydration of the proton. At all hydration levels the excited O-H stretch vibration of the hydrated proton shows an ultrafast vibrational relaxation with a time constant T1 ultrafast local heating of the protonated water cluster. This excess thermal energy, initially highly localized to the region of the excited proton, first re-distributes over the aqueous cluster and then dissipates into the surrounding acetonitrile matrix. For clusters with a triflic acid to H2O ratio of 1:3 these processes occur with time constants of 320 ± 20 fs and 1.4 ± 0.1 ps, respectively. The cooling of the clusters reveals a long-living, underlying transient absorption change with high anisotropy. We argue that this feature stems from the vibrational predissociation of a small fraction of the proton hydration structures, directly following the ultrafast infrared excitation. PMID:27333302

  7. Determination and correlation of cefuroxime acid solubility in (acetonitrile + water) mixtures

    Highlights: • The solubility of cefuroxime acid in different solvents was experimentally determined. • The experimental solubility data were correlated by three models. • The AIC was used to select the best solubility model. • The thermodynamic properties of cefuroxime acid in solution were obtained. - Abstract: The solubility of cefuroxime acid in (acetonitrile + water) mixtures was experimentally determined at temperatures from (278.15 to 313.15) K by using a dynamic method at atmospheric pressure. The solubility increased with the increasing of temperature, and it reached the maximum at acetonitrile molar fraction of 0.713 at constant temperature. The experimental solubility data were correlated well by using the modified Apelblat equation, the λh equation and the van’t Hoff equation, respectively. The Akaike’s Information Criterion (AIC) was used to select the best model for correlating the solubility of cefuroxime acid. Furthermore, the dissolution enthalpy, entropy and Gibbs free energy change of cefuroxime acid were also calculated by using the van’t Hoff equation

  8. Electronic structure calculations of acetonitrile cluster anions: Stabilization mechanism of molecular radical anions by solvation

    Systematic electronic structure calculations have been performed for (CH3CN)n-(n=2-10) anion clusters with the hybrid B3LYP and non-hybrid PW91 density-functional methods in order to understand the stabilization mechanism of an acetonitrile dimer radical anion core by solvent molecules. Since the excess negative charge is mainly localized on N atoms in the dimer anion core, solvent acetonitrile molecules are bound to the N atoms by C-H...Nδ- hydrogen-bond-like attractive interaction with the binding energy per bond being about 10-13kcal/mol. Due to this stabilization mechanism, the anion cluster for n>=4-6 is stable with respect to the electron autodetachment. Geometry optimization was also carried out for the (CH3CN)6- anion cluster where an excess electron was internally trapped. The size dependence of the stabilization energy and vertical detachment energy for the (CH3CN)n- anion clusters is discussed

  9. A tetranuclear cadmium(II) complex based on the 2-(quinolin-8-yloxy)acetonitrile ligand.

    Liu, Ming-Liang; Ye, Qiong

    2013-01-01

    The hydrothermal reaction of 2-(quinolin-8-yloxy)acetonitrile and Cd(ClO(4))(2) yielded the noncentrosymmetric coordination complex tetrakis[μ-2-(quinolin-8-yloxy)acetato]tetrakis[μ-2-(quinolin-8-yloxy)acetonitrile]tetracadmium tetrakis(perchlorate) dihydrate, [Cd(4)(C(11)H(8)NO(3))(4)(C(11)H(8)N(2)O)(4)](ClO(4))(4)·2H(2)O. The local coordination environment around the Cd(II) cation can be best described as a capped octahedron defined by two N atoms and five O atoms from three ligands. The Cd(II) cations are linked by the ligands with Cd-O-Cd and Cd-O-C-C-O-Cd bridges, forming tetranuclear units, there being two independent tertranuclear units in the structure. The fourfold rotoinversion centre sits at the centre of each Cd(4) core. The two perchlorate anions in the asymmetric unit are linked by the water molecule through O-H...O hydrogen bonds. PMID:23282905

  10. Application of Solid Phase Microextraction followed by Chromatograph-Flame Ionization Detector for Sampling and Analysis of Acetonitrile in Air

    NEMATULLAH KURD

    2015-10-01

    Full Text Available Acetonitrile used as a solvent in manufactures and affects to central nervous system from inhalation exposure. The aim of this study was to develop a micro-solid phase extraction method for the determination of acetonitrile in the air matrix. The sampling was performed with a small diameter fused silica fiber coated with a thin film of stationary phase and was subsequently desorbed and analyzed by gas chromatograph equipped with a flame ionization detector (GC/FID. The effects of laboratory and sampling parameters were investigated and applied to the determination of acetonitrile in air matrix. The Carboxen/PDMS as thecoating fiber showed better analytical performances compared to the PDMS fiber. Analysis of the data by ANOVA test at a 0.05 level of accuracy showed that the peak area of the sampler was significantly affected by temperature and humidity so that the optimum temperature was 20°C and the optimum humidity was 35%. Besides, the limit of detection (LOD and limit of quantification (LOQ for acetonitrile in the GC system were 0.05 and 0.15 μg/ml, respectively. The solid phase microextraction (SPME has been shown a suitable technique for sampling and analysis of acetonitrile in air. There was a good correlation between the SPME and national institute occupational safety and health (NIOSH 1010 method under the optimum conditions. 

  11. The response of Paracoccus sp. SKG to acetonitrile-induced oxidative stress.

    Kirankumar, B; Guruprasad, B Kulkarni; Santoshkumar, M; Anand, S Nayak; Karegoudar, T B

    2013-11-01

    Organic solvents enhance intracellular oxidative stress and induce various physiological responses in bacteria. The study shows the morphological changes in Paracoccus sp. SKG when exposed to higher concentrations of acetonitrile, which alter the composition of the membrane fatty acid that accompanies the increase in K(+) efflux. This enhances the oxidative stress with greater activities of catalase and super oxide dismutase (SOD). The increased oxidative stress results in the generation of free radicals, which was confirmed by electron paramagnetic resonance (EPR) studies. The free radical scavenging activities were measured by ABTS and DPPH to understand the non-enzymatic defensive system during oxidative stress. The studies demonstrate the increase in free radicals in association with enzymatic and non-enzymatic defense systems under solvent stress. PMID:24092001

  12. Kinetics and mechanism of the anilino lysis of O-ethyl phenyl phosphonochloridothioic in acetonitrile

    The nucleophilic substitution reactions of O-ethyl phenyl phosphonochloridothioic with substituted anilines (XC6H4NH2) and deuterated anilines (XC6H4ND2) are kinetically investigated in acetonitrile at 55.0 .deg. C. The deuterium kinetic isotope effects (DKIEs) invariably increase from a secondary inverse DKIE (kH/kD = 0.93) to a primary normal DKIE (kH/kD = 1.28) as the substituent of nucleophile (X) changes from electron-donating to electron-withdrawing. These can be rationalized by the gradual transition state (TS) variation from a backside to front side attack. A concerted SN2 mechanism is proposed. A trigonal bipyramidal TS is proposed for a backside attack while a hydrogen-bonded, four-center-type TS is proposed for a front side attack

  13. Isolation and identification of (3-methoxyphenyl)acetonitrile as a phytotoxin from meadowfoam (Limnanthes alba) seedmeal.

    Vaughn, S F; Boydston, R A; Mallory-Smith, C A

    1996-10-01

    Ethyl ether, ethanol, and water extracts of meadowfoam (Limnanthes alba Hartweg ex. Benth.) seedmeal were prepared and bioassayed against velvetleaf (Abutilon theophrasti Medicus) and wheat (Triticum aestivum L. "Cardinal"). Both the ethyl ether and ethanol fractions, but not the water extract, inhibited velvetleaf and wheat radicle elongation. Fractionation of the extracts indicated that (3-methoxyphenyl)acetonitrile (3-MPAN) was the active compound from both extracts, comprising >97% of the active ethanol fraction. 3-Methoxybenzyl isothiocyanate, which had been previously shown to be the major breakdown product of glucolimnanthin, the majorL. alba glucosinolate, was not detected in either extract. Radicle elongation of velvetleaf and wheat were inhibited by 3-MPAN with I50 (the concentration required to inhibit growth by 50%) values of approximately 4 × 10(-4) M (velvetleaf) and 7×10(-4) M (wheat). PMID:24227117

  14. Heterolytic and Homolytic N-NO Bond Dissociation Energies of N-Nitroso-benzenesulfonylmethylamines in Acetonitrile

    HAO Wei-Fang; Tang Hui; ZHU Xiao-Qing; CHENG Jin-Pei

    2003-01-01

    @@ Great interests have been accumulated in recent years in the chemistry and biochemistry of nitric oxide (NO) since the remarkable discoveries of its key roles in a wide range of human physiological processes. To elucidate the mechanistic details of NO migration from its donor to its acceptor, it is necessary to determine the Y-NO bind energy that registers the thermodynamic driving force for NO release and capture. In this paper the heterolytic and homolytic N-NO bond dissociation energies [ i. e., △Hhet(N-NO) and △Hhomo(N-NO)] for ten N-nitroso-p-substituted-benzensulfonyl methylamines in acetonitrile are offered, which were obtained from titration calorimetry and thermodynamic cycles, respectively (Scheme 1).

  15. Electrolyte Solvation and Ionic Association. VI. Acetonitrile-Lithium Salt Mixtures. Highly Associated Salts Revisited

    Borodin, Oleg [U.S. Army Research Lab., Adelphi, MD (United States); Han, Sang D. [North Carolina State Univ., Raleigh, NC (United States); Daubert, James S. [North Carolina State Univ., Raleigh, NC (United States); Seo, D. M. [North Carolina State Univ., Raleigh, NC (United States); Yun, Sung-Hyun [Gwangju Inst. of Science and Technology (Korea, Republic of); Henderson, Wesley A. [North Carolina State Univ., Raleigh, NC (United States); Pacific Northwest National Lab. (PNNL), Richland, WA (United States)

    2015-01-14

    Molecular dynamics (MD) simulations of acetonitrile (AN) mixtures with LiBF4, LiCF3SO3 and LiCF3CO2 provide extensive details about the molecular- and mesoscale-level solution interactions and thus explanations as to why these electrolytes have very different thermal phase behavior and electrochemical/physicochemical properties. The simulation results are in full accord with a previous experimental study of these (AN)n-LiX electrolytes. This computational study reveals how the structure of the anions strongly influences the ionic association tendency of the ions, the manner in which the aggregate solvates assemble in solution and the length of time in which the anions remain coordinated to the Li+ cations in the solvates which result in dramatic variations in the transport properties of the electrolytes.

  16. Structure and stereochemistry of electrochemically synthesized poly-(1-naphthylamine from neutral acetonitrile solution

    VESNA ANTIC

    2002-12-01

    Full Text Available Poly-(1-naphthylamine films were synthesized potentiodinamically and potentiostatically from 1-naphthylamine in neutral acetonitrile medium using a platinum electrode. These polymer films were investigated by infrared spectroscopy. Contrary to earlier published results neglecting the stereochemistry of the poly-(1-naphthylamine, we predict on the basis of quantum stereochemical analysis of the possible structural subunits of the polymer, that the ordinary N–C(4 coupled product is not predominant in the polymer because it is far removed from the expected planarity. Based on the results of IR investigations and semiempirical quantum chemical calculations, it is propose that the polymer products are formed via mixed N–C(4, N-C(5 and N–C(7 coupling routes. The heats of formation of the oxidized 1-naphthylamine dimers and hexamers were calculated.

  17. Standard Reduction Potentials for Oxygen and Carbon Dioxide Couples in Acetonitrile and N,N-Dimethylformamide

    Pegis, Michael L.; Roberts, John A.; Wasylenko, Derek J.; Mader, Elizabeth A.; Appel, Aaron M.; Mayer, James M.

    2015-12-21

    A variety of energy processes utilize the electrochemical interconversions of dioxygen and water, the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Reported here are the first estimates of the equilibrium reduction potential of the O2 + 4e– + 4H+ 2H2O couple in organic solvents. The values are +1.21 V in acetonitrile (MeCN) and +0.60 V in dimethylformamide (DMF), each versus the ferrocenium/ferrocene couple (Fc+/0) in the respective solvent (as are all the potentials reported here). The potentials have been determined using a thermochemical cycle that combines the free energy for transferring water from aqueous solution to organic solvent, -0.43 kcal mol-1 for MeCN and -1.47 kcal mol-1 for DMF, and the potential of the H+/H2 couple, –0.028 V in MeCN and –0.662 V in DMF. The H+/H2 couple in DMF has been directly measured electrochemically, using the previously reported procedure for the MeCN value. The thermochemical approach used for the O2/H2O couple can also be extended to the CO2/CO and CO2/CH4 couples to give values of -0.12 V and +0.15 V in MeCN, and -0.73 V and -0.48 V in DMF. Extensions to other reduction potentials are discussed. Additionally, the free energy for transfer of protons from water to organic solvent is roughly estimated as +14 kcal mol-1 for acetonitrile and +0.6 kcal mol-1 for dimethylformamide. This research was supported as part of the Center for Molecular Electrocatalysis, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences. Pacific Northwest National Laboratory is operated by Battelle for the U.S. Department of Energy.

  18. New method for the photo-chemiluminometric determination of benzoylurea insecticides based on acetonitrile chemiluminescence.

    Gil García, M D; Martínez Galera, M; Santiago Valverde, R

    2007-03-01

    The viability of tandem photochemical reaction-chemiluminescence detection has been studied for the determination of five benzoylurea insecticides, namely, diflubenzuron, triflumuron, hexaflumuron, lufenuron and flufenoxuron. The 'on-line' photochemical reaction of benzoylurea pesticides provides an enhanced chemiluminescence response of the pesticides during their oxidation by potassium hexacyanoferrate(III) and sodium hydroxide, whose signal increases with the percentage of acetonitrile in the reaction medium. The determination was performed using a photoreactor consisting of a PFA (perfluoroalkoxy) tube reactor coil (5 mx1.6-mm O.D. and 0.8-mm I.D.) and an 8-W xenon lamp. As the yield of the photoderivatization process and the chemiluminescent signals depend on the percentage of acetonitrile, the chromatographic column (a Gemini C18, Phenomenex 150 mmx4.6 mm, 5-microm particle size) was chosen with the aim of using high percentages of this organic solvent in the mobile phase. Previous studies showed that the rate of the chemiluminescent reaction was very fast. Therefore, a modification was carried out in the detector in order to mix the analytes and reactants as near as possible to the measure cell. The optimised method was validated with respect to linearity, precision, limits of detection and quantification accuracy. Under the optimised conditions, linear working range extends three orders of magnitude with the relative standard deviation of intra-day precision below 10% and detection limits between 0.012 and 0.18 microg mL-1, according to the compound. The proposed method has been successfully applied to the determination of benzoylureas in cucumber with good results. PMID:17205265

  19. Standard Reduction Potentials for Oxygen and Carbon Dioxide Couples in Acetonitrile and N,N-Dimethylformamide.

    Pegis, Michael L; Roberts, John A S; Wasylenko, Derek J; Mader, Elizabeth A; Appel, Aaron M; Mayer, James M

    2015-12-21

    A variety of next-generation energy processes utilize the electrochemical interconversions of dioxygen and water as the oxygen reduction reaction (ORR) and the oxygen evolution reaction (OER). Reported here are the first estimates of the standard reduction potential of the O2 + 4e(-) + 4H(+) ⇋ 2H2O couple in organic solvents. The values are +1.21 V in acetonitrile (MeCN) and +0.60 V in N,N-dimethylformamide (DMF), each versus the ferrocenium/ferrocene couple (Fc(+/0)) in the respective solvent (as are all of the potentials reported here). The potentials have been determined using a thermochemical cycle that combines the free energy for transferring water from aqueous solution to organic solvent, -0.43 kcal mol(-1) for MeCN and -1.47 kcal mol(-1) for DMF, and the potential of the H(+)/H2 couple, - 0.028 V in MeCN and -0.662 V in DMF. The H(+)/H2 couple in DMF has been directly measured electrochemically using the previously reported procedure for the MeCN value. The thermochemical approach used for the O2/H2O couple has been extended to the CO2/CO and CO2/CH4 couples to give values of -0.12 and +0.15 V in MeCN and -0.73 and -0.48 V in DMF, respectively. Extensions to other reduction potentials are discussed. Additionally, the free energy for transfer of protons from water to organic solvent is estimated as +14 kcal mol(-1) for acetonitrile and +0.6 kcal mol(-1) for DMF. PMID:26640971

  20. Tetrakis(acetonitrilecopper(I hydrogen oxalate–oxalic acid–acetonitrile (1/0.5/0.5

    A. Timothy Royappa

    2013-10-01

    Full Text Available In the title compound, [Cu(CH3CN4](C2HO4·0.5C2H2O4·0.5CH3CN, the CuI ion is coordinated by the N atoms of four acetonitrile ligands in a slightly distorted tetrahedral environment. The oxalic acid molecule lies across an inversion center. The acetonitrile solvent molecule is disordered across an inversion center and was refined with half occupancy. In the crystal, the hydrogen oxalate anions and oxalic acid molecules are linked via O—H...O hydrogen bonds, forming chains along [010].

  1. 8-Hydroxy-2-methylquinolinium dichlorido(2-methylquinolin-8-olato-κ2N,Ozincate acetonitrile disolvate

    Ezzatollah Najafi

    2011-09-01

    Full Text Available The reaction of 2-methyl-8-hydroxyquinoline and zinc chloride in acetonitrile affords the title solvated salt, (C10H10NO[Zn(C10H8NOCl2]·2CH3CN, in which the ZnII atom is coordinated by an N,O-chelating 2-methylquinolin-8-olate ligand and two chloride ligands in a distorted tetrahedral geometry. The cation is linked to the heterocyclic anion by an O—H...O hydrogen bond and the quinolinium H atom forms a intermolecular N—H...N hydrogen bond with one of the acetonitrile solvent molecules.

  2. 8-Hydroxy-2-methylquinolinium dibromido(2-methylquinolin-8-olato-κ2N,Ozincate acetonitrile monosolvate

    Ezzatollah Najafi

    2011-09-01

    Full Text Available The reaction of 2-methyl-8-hydroxyquinoline and zinc bromide in acetonitrile affords the title solvated salt, (C10H10NO[ZnBr2(C10H8NO]·CH3CN, in which the ZnII ion is coordinated by a N,O-chelating 2-methylquinolin-8-olate ligand and two bromide ligands in a distorted tetrahedral geometry. The cation is linked to the anion by an O—H...O hydrogen bond and the quinolinium H atom forms an intermolecular N—H...N hydrogen bond with the acetonitrile solvent molecule.

  3. Direct Electrochemical Evidence of the Dissociation and Adsorption Behavior of Acetonitrile at Gold Electrodes by Ultrafast Voltammetry

    2006-01-01

    Ultrafast cyclic voltammetry was used to study the redox behavior of a gold electrode in acetonitrile. The direct electrochemical evidence of the dissociation and adsorption behavior of acetonitrile at gold electrodes was found. It could be stated that two consecutive redox paths are involved, each with a special adsorption state acting as the reaction intermediate. The mean value,obtained of the electron-transfer rate constant of the second path, was 1.3 × 105 s-1 with a standard deviation of 0.24 × 105 s-1.

  4. Effect of the physicochemical parameters of benzimidazole molecules on their retention by a nonpolar sorbent from an aqueous acetonitrile solution

    Shafigulin, R. V.; Safonova, I. A.; Bulanova, A. V.

    2015-09-01

    The effect of the structure of benzimidazoles on their chromatographic retention on octadecyl silica gel from an aqueous acetonitrile eluent was studied. One- and many-parameter correlation equations were obtained by linear regression analysis, and their prognostic potential in determining the retention factors of benzimidazoles under study was analyzed.

  5. Pyridinolyses of O-Propyl and O-Isopropyl Phenyl Phosphonochloridothioates in Acetonitrile

    Barai, Hasi Rani; Lee, Hai Whang [Inha Univ., Incheon (Korea, Republic of)

    2013-09-15

    Continuing the kinetic studies on the pyridinolyses of the phosphonochloridothioates, the nucleophilic substitution reactions of O-propyl (4) and O-isopropyl (5) phenyl phosphonochloridothioates with X-pyridines have been carried out kinetically in acetonitrile (MeCN) at 35.0 ± 0.1 .deg. C (Scheme 1). The kinetic results of the present work are compared with those of the pydidinolyses of Y-O-aryl methyl [1; Me(YC{sub 6}H{sub 4}O)P(=S)Cl],{sup 1a} O-methyl phenyl [2;Ph(MeO)P(=S)Cl],1b O-ethyl phenyl [3; Ph(EtO)P(=S)Cl],{sup 1b} Y-O-aryl phenyl [6; Ph(YC{sub 6}H{sub 4}O)P(=S)Cl]{sup 1c} and Y-S-aryl phenyl [7; Ph(YC{sub 6}H{sub 4}S)P(=S)Cl]{sup 1d} phosphonochloridothioates, based on the reactivities, selectivity parameters, free energy correlations and reaction mechanisms.

  6. Electrical conductivity and dielectric relaxation of 2-(antipyrin-4-ylhydrazono)-2-(4-nitrophenyl)acetonitrile

    The electrical and dielectric properties of the synthesized 2-(antipyrin-4-ylhydrazono)-2-(4-nitrophenyl)acetonitrile (AHNA) have been studied. The direct and alternating current (DC and AC) conductivities and complex dielectric constant were investigated in temperature range 303–403 K. The AC conductivity and dielectric properties of AHNA were investigated over frequency range 100 Hz–5 MHz. From DC and AC measurements, electrical conduction is found to be a thermally activated process. The frequency-dependent AC conductivity obeys Jonscher's universal power law in which the frequency exponent decreases with increasing temperature. The correlated barrier hopping (CBH) is the predominant model for describing the charge carrier transport in which the electrical parameters are evaluated. The activation energy is found to decrease with increasing frequency. The behaviors of dielectric and dielectric loss are discussed in terms of a polarization mechanism. The dielectric loss shows frequency power law from which the maximum barrier height is determined as 0.19 eV in terms of the Guintini model

  7. Electrical conductivity and dielectric relaxation of 2-(antipyrin-4-ylhydrazono)-2-(4-nitrophenyl)acetonitrile

    El-Menyawy, E.M., E-mail: emad_elmenyawy@yahoo.com [Solid State Electronics Laboratory, Solid State Physics Department, Physics Division, National Research Center, Dokki, Cairo 12311 (Egypt); Zedan, I.T. [Basic Science Department, High Institute of Engineering and Technology, El-Arish, North Sinai (Egypt); Nawar, H.H. [Department of Chemistry, Faculty of Education, Al Jabal Al Gharbi University (Libya)

    2014-03-15

    The electrical and dielectric properties of the synthesized 2-(antipyrin-4-ylhydrazono)-2-(4-nitrophenyl)acetonitrile (AHNA) have been studied. The direct and alternating current (DC and AC) conductivities and complex dielectric constant were investigated in temperature range 303–403 K. The AC conductivity and dielectric properties of AHNA were investigated over frequency range 100 Hz–5 MHz. From DC and AC measurements, electrical conduction is found to be a thermally activated process. The frequency-dependent AC conductivity obeys Jonscher's universal power law in which the frequency exponent decreases with increasing temperature. The correlated barrier hopping (CBH) is the predominant model for describing the charge carrier transport in which the electrical parameters are evaluated. The activation energy is found to decrease with increasing frequency. The behaviors of dielectric and dielectric loss are discussed in terms of a polarization mechanism. The dielectric loss shows frequency power law from which the maximum barrier height is determined as 0.19 eV in terms of the Guintini model.

  8. Kinetics and Mechanism of Anilinolyses of Ethyl Methyl, Ethyl Propyl and Diisopropyl Chlorothiophosphates in Acetonitrile

    Barai, Hasi Rani; Lee, Hai Whang [Inha Univ., Incheon (Korea, Republic of); Ehtesham Ul Hoque, Md. [Govt. Brojomohun College, Barisal (Bangladesh)

    2013-12-15

    Nucleophilic substitution reactions of ethyl methyl (2), ethyl propyl (4) and diisopropyl (7) chlorothiopho-sphates with substituted anilines and deuterated anilines are investigated kinetically in acetonitrile at 55.0 .deg. C. A concerted mechanism is proposed based on the selectivity parameters. The deuterium kinetic isotope effects (DKIEs; k{sub H}/k{sub D}) are secondary inverse (k{sub H}/k{sub D} = 0.66-0.99) with 2, primary normal and secondary inverse (k{sub H}/k{sub D} = 0.78-1.19) with 4, and primary normal (k{sub H}/k{sub D} = 1.06-1.21) with 7. The primary normal and secondary inverse DKIEs are rationalized by frontside attack involving hydrogen bonded, four-center-type transition state, and backside attack involving in-line-type transition state, respectively. The anilinolyses of ten chloro-thiophosphates are examined based on the reactivity, steric effect of the two ligands, thio effect, reaction mechanism, DKIE and activation parameter.

  9. Thermodynamic models for determination of the solubility of dibenzothiophene in (methanol + acetonitrile) binary solvent mixtures

    Highlights: • The solubility increased with increasing temperature. • The solubility decreased with the rise of the ratio of the methanol. • The solubility data were fitted using Apelblat equation, CNIBS/R–K and JA model. • The Gibbs free energy, enthalpy and entropy were calculated by the van’t Hoff analysis. - Abstract: In this paper, we focused on solubility and solution thermodynamics of dibenzothiophene. By the gravimetric method, the solubility of dibenzothiophene was measured in (methanol + acetonitrile) binary solvent mixtures at temperatures from (278.15 to 333.15) K under atmosphere pressure. The solubility data were fitted using a modified Apelblat equation, a variant of the combined nearly ideal binary solvent/Redich–Kister (CNIBS/R–K) model and Jouyban–Acree model. Computational results showed that the modified Apelblat equation was superior to the other two equations. In addition, the thermodynamic properties of the solution process, including the Gibbs free energy, enthalpy, and entropy, were calculated by the van’t Hoff analysis. The experimental results showed that methanol could be used as effective anti-solvents in the crystallization process

  10. Competitive solvation of (bis)(trifluoromethanesulfonyl)imide anion by acetonitrile and water

    Chaban, Vitaly

    2014-01-01

    Competitive solvation of an ion by two or more solvents is one of the key phenomena determining the identity of our world. Solvation in polar solvents frequently originates from non-additive non-covalent interactions. Pre-parametrized potentials poorly capture these interactions, unless the force...... temperature coupling. Using a competitive solvation of (bis)(trifluoromethanesulfonyl)imide anion in acetonitrile and water, the work demonstrates efficiency and robustness of PM7-MD. (C) 2014 Elsevier B.V. All rights reserved.......Competitive solvation of an ion by two or more solvents is one of the key phenomena determining the identity of our world. Solvation in polar solvents frequently originates from non-additive non-covalent interactions. Pre-parametrized potentials poorly capture these interactions, unless the force...... field derivation is repeated for every new system. Development cost increases drastically as new chemical species are supplied. This work represents an alternative simulation approach, PM7-MD, by coupling the latest semiempirical parametrization, PM7, with equation-of-motion propagation scheme and...

  11. Quantitative determination of aflatoxin B1 concentration in acetonitrile by chemometric methods using terahertz spectroscopy.

    Ge, Hongyi; Jiang, Yuying; Lian, Feiyu; Zhang, Yuan; Xia, Shanhong

    2016-10-15

    Aflatoxins contaminate and colonize agricultural products, such as grain, and thereby potentially cause human liver carcinoma. Detection via conventional methods has proven to be time-consuming and complex. In this paper, the terahertz (THz) spectra of aflatoxin B1 in acetonitrile solutions with concentration ranges of 1-50μg/ml and 1-50μg/l are obtained and analyzed for the frequency range of 0.4-1.6THz. Linear and nonlinear regression models are constructed to relate the absorption spectra and the concentrations of 160 samples using the partial least squares (PLS), principal component regression (PCR), support vector machine (SVM), and PCA-SVM methods. Our results indicate that PLS and PCR models are more accurate for the concentration range of 1-50μg/ml, whereas SVM and PCA-SVM are more accurate for the concentration range of 1-50μg/l. Furthermore, ten unknown concentration samples extracted from mildewed maize are analyzed quantitatively using these methods. PMID:27173565

  12. Spectroscopic investigation of europium benzoate in acetonitrile: Luminescence enhancement and complexation studies

    Luminescence from Eu3+ complexed with benzoic acid (BA) has been studied using acetonitrile (MeCN) as solvent. More than two orders luminescence enhancement is found as compared to Eu3+–BA complex in aqueous medium. The lifetime of Eu3+ in this complex is 900 μs which is much higher as compared to 118 μs in aqueous medium, suggesting the luminescence enhancement is a result of reduction in non-radiative decay channels in MeCN medium. Luminescence spectroscopy along with UV–vis spectroscopy is used to study the complexation behavior of Eu3+–BA in this medium. In contrary to aqueous medium where Eu3+–BA forms ML and ML2 type species, spectroscopic data reveal formation of only ML3 complex with composition Eu(BA)3(MeCN)6 in MeCN medium. Absorbance, luminescence lifetimes and the ratio of areas of 615–592 nm peaks are used in HypSpec computation program to determine the log β for the ML3 complex. - Highlights: • Luminescence and complexation of Eu3+–BA have been studied in MeCN. • The luminescence intensity of Eu3+–BA is 320 times more in MeCN compared to aqueous medium. • Luminescence enhancement is a result of sensitization and reduction in non-radiative decay channels in MeCN. • Eu3+ forms only ML3 type complex with BA in MeCN contrary to aqueous medium where it forms ML and ML2 type species

  13. Full characterization of polypyrrole thin films electrosynthesized in room temperature ionic liquids, water or acetonitrile

    Highlights: • Polypyrrole films were electrodeposited from three room temperature ionic liquids. • Polymer films were characterized using many surface analysis techniques. • The incorporation of anions and/or cations inside the polymer films was evidenced. • The influence of the ionic liquid on the polymer properties was deeply studied. - Abstract: Pyrrole was electrochemically oxidized in two conventional media (water and acetonitrile) and in three room temperature ionic liquids: 1-butyl-3-methylimidazolium hexafluorophosphate, 1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, and 1-butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide. Infrared and Raman Spectroscopies confirmed the formation of polypyrrole by electropolymerization but were unable to demonstrate the presence of anions in the polymer films. The use of ionic liquids as growth media resulted in polymer films having a good electrochemical activity. The difference of activity from one polymer film to the other was mainly attributed to the difference of viscosity between the solvents used. The morphological features of the polypyrrole films were also fully studied. Profilometric measurements demonstrated that polymer films grown, at the same potential, in ionic liquids were thinner and had a smaller roughness than those grown in other solvents. Atomic Force Microscopy showed that polypyrrole films had nearly similar micrometric nodular structure whatever the growth medium even if some differences of porosity and homogeneity were observed using Scanning Electron Microscopy. The incorporation of counter-anions at the top surface of the films was finally evidenced by X-ray Photoelectron Spectroscopy. These anions were also incorporated inside the polymer film with a uniform distribution as shown by Glow Discharge Optical Emission Spectroscopy

  14. Reduction of aromatic nitro radical anion in acetonitrile. Dougle-layer effect on the second electron transfer

    Mořkovská, Petra; Hromadová, Magdaléna; Pospíšil, Lubomír; Giannarelli, S.

    2006. Roč. 601, - (2006), s. 996. ISSN 1091-8213. [ECS Meeting Denver Colorado /209./. 07.05.06-11.05.06, Denver] R&D Projects: GA AV ČR IAA400400505; GA MŠk LC510 Grant ostatní: MURST(XE) COFIN2000 Institutional research plan: CEZ:AV0Z40400503 Keywords : electrochemistry * acetonitrile * double-layer structure Subject RIV: CG - Electrochemistry

  15. Complexation dynamics of CH3SCN and Li(+) in acetonitrile studied by two-dimensional infrared spectroscopy.

    Kwon, YoungAh; Park, Sungnam

    2015-10-01

    Ion-molecule complexation dynamics were studied with CH3SCN and Li(+) in acetonitrile by vibrationally probing the nitrile stretching vibration of CH3SCN. The nitrile stretching vibration of CH3SCN has a long lifetime (T1 = ∼90 ps) and its frequency is significantly blue-shifted when CH3SCN is bound with Li(+) ions to form a CH3SCNLi(+) complex in acetonitrile. Such spectral properties enable us to distinguish free CH3SCN and the CH3SCNLi(+) complex in solutions and measure their dynamics occurring on hundred picosecond timescales. For the complexation between CH3SCN and Li(+) in acetonitrile, the change in enthalpy (ΔH = -7.17 kJ mol(-1)) and the change in entropy (ΔS = -34.4 J K(-1) mol(-1)) were determined by temperature-dependent FTIR experiments. Polarization-controlled infrared pump-probe (IR PP) spectroscopy was used to measure the population decay and orientational dynamics of free CH3SCN and the CH3SCNLi(+) complex. Especially, the orientational relaxation of the CH3SCNLi(+) complex was found to be almost 3 times slower than those of free CH3SCN because Li(+) ions strongly interact with the neighboring solvents. Most importantly, the complexation dynamics of CH3SCN and Li(+) in acetonitrile were successfully measured in real time by 2DIR spectroscopy for the first time and the dissociation and association time constants were directly determined by using the two-species exchange kinetic model. Our experimental results provide a comprehensive overview of the ion-molecule complexation dynamics in solutions occurring under thermal equilibrium conditions. PMID:26323322

  16. Vapor pressures, osmotic and activity coefficients for (LiBr + acetonitrile) between the temperatures (298.15 and 343.15) K

    Precise vapor pressure data for pure acetonitrile and (LiBr + acetonitrile) are given for temperatures ranging from T=(298.15 to 343.15) K. The molality range is from m=(0.0579 to 0.8298) mol · kg-1. The osmotic coefficients are calculated by taking into account the second virial coefficient of acetonitrile. The parameters of the extended Pitzer ion interaction model of Archer and the mole fraction-based thermodynamic model of Clegg-Pitzer are evaluated. These models accurately reproduce the available osmotic coefficients. The parameters of the extended Pitzer ion interaction model of Archer are used to calculate the mean molal activity coefficients

  17. Tris(acetonitrile-κN{2,6-bis[(diphenylphosphanylamino]-4-ethoxy-1,3,5-triazine-κ3P,N1,P′}iron(II bis(tetrafluoridoborate acetonitrile disolvate

    Moumita Koley

    2011-12-01

    Full Text Available In the title compound, [Fe(CH3CN3(C29H27N5OP2](BF42·2CH3CN, the FeII ion is octahedrally coordinated by a meridionally chelating tridentate pincer-type PNP ligand derived from 2,6-diamino-4-ethoxy-1,3,5-triazine and by three acetonitrile molecules. The four Fe—N bond lengths range from 1.9142 (12 to 1.9579 (11 Å, while the Fe—P bonds are 2.2452 (4 and 2.2506 (4 Å [P—Fe—P = 165.523 (14°], consistent with FeII in a low-spin state. Unlike related Fe PNP complexes based on 2,6-diaminopyridine, the BF4 anions are not hydrogen bonded to the two NH groups of the pincer ligand but show instead anion–π interactions with the triazine ring and acetonitrile molecules in addition to ten C—H...F interactions. Most remarkable among these is an anion–π(triazine interaction with a short distance of 2.788 (2 Å between one F and the centroid of the π-acidic triazine ring. The corresponding shortest distance between this F atom and a triazine carbon atom is 2.750 (2 Å. The two NH groups of the pincer ligand donate N—H...N hydrogen bonds to the triazine N atom of a neighbouring complex and to an uncoordinated acetonitrile molecule. This last molecule is in a side-on head-to-tail association with the second uncoordinated acetonitrile at C...N distances of 3.467 (2 and 3.569 (2 Å. In contrast to several related compounds with diaminopyridine- instead of diaminotriazine-based PNP ligands, the title crystal structure is remarkably well ordered. This suggests that the diaminotriazine moiety exerts notable crystal structure stabilizing effects.

  18. Biodegradation of acetonitrile by cells of Candida guilliermondii UFMG-Y65 immobilized in alginate, k-carrageenan and citric pectin

    Dias João Carlos T.

    2000-01-01

    Full Text Available Different encapsulation matrices were tested for immobilized cells of Candida guilliermondii UFMG-Y65 used for acetonitrile degradation. Acetonitrile degradation by free cells and cells immobilized in Ba-alginate, kappa-carrageenan and citric pectin was studied. The rate of acetonitrile degradation was monitored for 120 h by measuring yeast growth and ammonia concentration. Different alginate concentrations did not affect cell viability, but the period of incubation in BaCl2 solution reduced the number of viable cells. Likewise, the gel nature and the matrix structure of the support resulting from the cell immobilization conditions were of fundamental importance for biocatalyst activity and performance, affecting substantially the patterns of microbial growth and enzymatic activity. Alginate-immobilized cells degraded acetonitrile more efficiently than kappa-carrageenan or citric pectin-immobilized cells.

  19. Spectroscopic and quantum-chemical investigation of association of ions in acetonitrile - LiX (X=I, ClO4, NCS) systems

    Data on association constants of ions in acetonitrile-salt binary systems, obtained from the data on intensity of IR absorption bands of acetonitrile (Acn) molecules contained in solvate shells of Li+ cations, have been analyzed. Using the CCP MO LCAO semiempirical method in the PPDP approximation, electronic structure of acetonitrile molecule and AcnkLi+ and AcnmLi+X- complexes has been studied. It is ascertained that relative stability of ionic pairs Acn3Li+X-, estimated by the squares of their dipole momenta (characterizing solvation energy) increases in the series X=I, ClO4, NCS in agreement with data of spectroscopic experiment, according to which the constant of ion association for LiNCS solution in acetonitrile is much higher than for the systems CH3CN-LiI and CH3CN-LiClO4. 13 refs.,2 figs., 2 tabs.64

  20. cis-Bis(acetonitrile-κNbis(2,2′-bipyridine-κ2N,N′ruthenium(II tetrafluoridoborate

    Ying Wang

    2012-01-01

    Full Text Available In the cation of the title compound, [Ru(CH3CN2(C10H8N22](BF42, the RuII atom is six-coordinated in a distorted octahedral geometry by the N atoms of the two 2,2′-bipyridine (bpy ligands and two cis-arranged acetonitrile molecules. The dihedral angles formed by the pyridine rings of the bpy ligands are 8.86 (12 and 10.12 (14°. In the crystal, the cations and anions are linked by C—H...F hydrogen bonds into a three-dimensional network.

  1. A New Look at the Stability of Dimethyl Sulfoxide and Acetonitrile in Li-O2 Batteries

    Younesi, Reza; Norby, Poul; Vegge, Tejs

    2014-01-01

    Dimethyl sulfoxide (DMSO) and acetonitrile (MeCN) have recently been highlighted as promising electrolyte solvents for Li-O2 batteries. Possible reactions between these two solvents and Li2O2 are here discussed using X-ray photoelectron spectroscopy to analyze surface of the Li2O2 powder after...... direct contact with the solvents for different times of exposure. The results indicated that Li2O2 decomposes DMSO solvents, whereas no indication of degradation of MeCN by Li2O2 was observed. © 2014 The Electrochemical Society....

  2. Catena-Poly[[bis(acetonitrile-κN)manganese(II)]-bis(μ-trifluoromethanesulfonato-κ2O:O')

    M. Lutz; Schreurs, A.M.M.; Spek, A.L.; Moelands, M.A.H.; Klein Gebbink, R.J.M.

    2009-01-01

    The title compound, [Mn(CF3SO3)2(CH3CN)2]n, has an MnII cation on an inversion centre in an octahedral environment. The trifluoromethanesulfonate anions act as bridging ligands and form a one-dimensional coordination polymer in the direction of the a axis. The F atoms of the trifluoromethanesulfonate anions form layers parallel to the ab plane, but despite short intermolecular distances, no stabilizing F...F interactions are detected. The Mn—N and C—C bonds of the acetonitrile ligand are anal...

  3. Stacking and Analysis of Melamine in Milk Products with Acetonitrile-Salt Stacking Technique in Capillary Electrophoresis

    Yu Kong

    2014-01-01

    Full Text Available Melamine was measured in real milk products with capillary electrophoresis (CE based on acetonitrile-salt stacking (ASS method. Real milk samples were deproteinized with acetonitrile at a final concentration of 60% (v/v and then injected hydrodynamically at 50 mBar for 40.0 s. The optimized buffer contains 80.0 mmol/L pH 2.8 phosphates. Melamine could be detected within 20.0 min at +10 kV with a low limit of detection (LOD of 0.03 μmol/L. Satisfactory reproducibility (inter- and intraday RSD% both for migration time and peak area was lower than 5.0% and a wide linearity range of 0.05 μmol/L ~ 10.0 μmol/L were achieved. The proposed method was suitable for routine assay of MEL in real milk samples that was subjected to a simple treatment step.

  4. On-column nitrosation of amines observed in liquid chromatography impurity separations employing ammonium hydroxide and acetonitrile as mobile phase.

    Myers, David P; Hetrick, Evan M; Liang, Zhongming; Hadden, Chad E; Bandy, Steven; Kemp, Craig A; Harris, Thomas M; Baertschi, Steven W

    2013-12-01

    The availability of high performance liquid chromatography (HPLC) columns capable of operation at pH values up to 12 has allowed a greater selectivity space to be explored for method development in pharmaceutical analysis. Ammonium hydroxide is of particular value in the mobile phase because it is compatible with direct interfacing to electrospray mass spectrometers. This paper reports an unexpected N-nitrosation reaction that occurs with analytes containing primary and secondary amines when ammonium hydroxide is used to achieve the high pH and acetonitrile is used as the organic modifier. The nitrosation reaction has generality. It has been observed on multiple columns from different vendors and with multiple amine-containing analytes. Ammonia was established to be the source of the nitroso nitrogen. The stainless steel column frit and metal ablated from the frit have been shown to be the sites of the reactions. The process is initiated by removal of the chromium oxide protective film from the stainless steel by acetonitrile. It is hypothesized that the highly active, freshly exposed metals catalyze room temperature oxidation of ammonia to NO but that the actual nitrosating agent is likely N(2)O(3). PMID:24182763

  5. Gas-phase chemistry of curium: Reactions of Cm+ and CmO+ with alkenes, acetonitrile, and hexafluoropropene

    The metal ions, Cm+, U+, and Tb+, and their oxides, MO+, were reacted in the gas phase with alkenes, acetonitrile, and hexafluoropropene, Product compositions and abundances provide a survey of essential aspects of the gas-phase chemistry of the curium cation, now the heaviest element for which such systematic studies have been carried out (U and Tb were included to provide comparisons). Of particular interest is the difference in behavior between the 4f lanthanide and 5f actinide series and variations in chemistry across the actinide series. The primary emphasis was on reactions with alkenes, particularly dehydrogenation, as indicative of the ability of a M+ to activate C-H bonds (the extent of C-C activation was generally in parallel with that of C-H activation). With acetonitrile and all of the alkenes (except ethene), the three M+ ions induced dehydrogenation. Variations were evident for the different reactant substrates, but the overall qualitative ordering of dehydrogenation efficiency was U+ > Tb+ > Cm+. With hexafluoropropene, the primary reaction channel was F abstraction and the discrepant reactivities reflected the propensity for U to oxidize to higher valence states compared to Cm or Tb. The terminal MFn+ were CmIIIF2+, TbIIIF2+, and UIVF4+, and among the MO+, only UO+ induced F abstraction, producing UOFn+ with n = 1--3

  6. Thermodynamic surface properties of [BMIm][NTf2] or [EMIm][NTf2] binary mixtures with tetrahydrofuran, acetonitrile or dimethylsulfoxide

    Highlights: ► We report the investigations of surface tensions of binary systems of ionic liquids with aprotic substances. ► DMSO similarly like water has higher surface tension in comparison with ionic liquids under test. ► It seems that surface activity of aprotic substance in mixture with ionic liquid is different than of alcohols. ► Real surface activity of aprotic substance in binary mixtures is always lower than the ideal one. -- Abstract: The surface tension, σ, of binary mixtures of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [BMIm][NTf2] with tetrahydrofuran (oxolane, thf), acetonitrile, dimethylsulfoxide ((methylsufinyl)methane, dmso) and of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl) imide [EMIm][NTf2] with dimethylsufoxide was measured between (293.15 and 313.15) K using the pendant drop method. On the basis of experimental σ values and activity coefficients of solutes in their solutions with ionic liquid obtained from vapor pressure measurement, Gibbs excess surface concentrations of thf, acetonitrile or dmso in mixtures with [BMIm][NTf2] or [EMIm][NTf2] were determined. The results are discussed in terms of possible interactions between ILs and aprotic polar substances

  7. Isomerization and fragmentation of acetonitrile upon interaction with N(4S) atoms: the chemistry of nitrogen in dense molecular clouds

    Mencos, Alejandro; Krim, Lahouari

    2016-08-01

    We experimentally show that the reaction between ground state nitrogen atoms N(4S) and acetonitrile CH3CN can lead to two distinct chemical pathways that are both thermally activated at very low temperatures. First is CH3CN isomerization which produces CH3NC and H2CCNH. Second is CH3CN decomposition which produces HNC and CH3CNH+CN- fragments, with the possible release of H2. Our results reveal that the mobility of N(4S)-atoms is stimulated in the 3-11 K temperature range, and that its subsequent encounter with one acetonitrile molecule is sufficient for the aforementioned reactions to occur without the need for additional energy to be supplied to the CH3CN + N(4S) system. These findings shed more light on the nitrogen chemistry that can possibly take place in dense molecular clouds, which until now was thought to only involve high-energy processes and therefore be unlikely to occur in such cold and dark interstellar regions. The reaction pathways we propose in this study have very important astrochemical implications, as it was shown recently that the atomic nitrogen might be more abundant, in many interstellar icy grain mantles, than previously thought. Also, these reaction pathways can now be considered within dense molecular clouds, and possibly affect the branching ratios for N-bearing molecules computed in astrochemical modelling.

  8. Distribution of pesticides in n-hexane/water and n-hexane/acetonitrile systems and estimation of possibilities of their extraction isolation and preconcentration from various matrices.

    Zayats, M F; Leschev, S M; Petrashkevich, N V; Zayats, M A; Kadenczki, L; Szitás, R; Szemán Dobrik, H; Keresztény, N

    2013-04-24

    Distribution of 150 most widely used pesticides of different chemical classes (amides, anilinopirimidines, aromatics, benzenesulfonates, carbamates, dicarboximides, organophosphorus compounds, phenyl esters, phenylureas, pyrazoles, pyrethroids, pyrimidines, strobilurins, sulfamides, triazines, triazoles, etc.) in n-hexane/water and n-hexane/acetonitrile systems was investigated at 25°C. Distribution constants of pesticides (P) have been calculated as ratio of pesticide concentration in n-hexane to its concentration in water or acetonitrile phase. HPLC and GC methods were used for pesticides determination in phases. It was found that the overwhelming majority of pesticides are hydrophobic, i.e. in n-hexane/water system LgP≫0, and the difference in LgP values can reach 9.1 units. Replacement of water for acetonitrile leads to dramatic fall of LgP values reaching 9.5 units. The majority of LgP values in this case are negative and their differences is strongly leveled in comparison with a hexane/water system. Thus, maximal difference in pesticides LgP values for n-hexane/acetonitrile system is 3.2 units. It is shown that n-hexane can be used for selective and efficient extraction and preconcentration of pesticides from water matrices. On the other hand, acetonitrile is effective for the isolation and preconcentration of pesticides from hydrocarbon and vegetable oil matrices. The distribution constants described in the paper may be effectively used for the estimation of possibilities of extraction isolation, preconcentration and separation of pesticides. PMID:23567114

  9. The role of water in the photocatalytic degradation of acetonitrile and toluene in gas-solid and liquid-solid regimes

    Leonardo Palmisano

    2006-02-01

    Full Text Available Photocatalytic degradation of acetonitrile and toluene was carried out both in gas-solid and in liquid-solid regimes by using commercial TiO2 samples (Merck and Degussa P25. The investigation was mainly aimed to study the influence of water present in the reaction environment on the mechanism and degradation rate of two probe molecules. In gas-solid regime, the reacting mixture consisted of toluene or acetonitrile, oxygen, nitrogen, and water vapour. The main degradation product of toluene was CO2 with small amounts of benzaldehyde. In the presence of water vapour, the activity of TiO2 Merck remained stable but greatly decreased if water was absent. TiO2 Degussa P25 continuously deactivated, even in the presence of water vapour. With both catalysts, the photodegradation products of acetonitrile were CO2 and HCN; the activity was stable and was independent of the presence of water vapour in the reacting mixture. The production of HCN represents a drawback of acetonitrile photocatalytic degradation but the elimination of HCN is not actually a problem. In liquid-solid regime, the main intermediates of toluene photodegradation were p-cresol and benzaldehyde; traces of pyrogallol and benzyl alcohol were also found. Benzoic acid, hydroquinone, and trans, trans muconic acid were detected only when TiO2 Merck was used. The photodegradation products of acetonitrile were cyanide, cyanate, formate, nitrate, and carbonate ions.

  10. The role of water in the photocatalytic degradation of acetonitrile and toluene in gas-solid and liquid-solid regimes

    2006-01-01

    Full Text Available Photocatalytic degradation of acetonitrile and toluene was carried out both in gas-solid and in liquid-solid regimes by using commercial TiO 2 samples (Merck and Degussa P25. The investigation was mainly aimed to study the influence of water present in the reaction environment on the mechanism and degradation rate of two probe molecules. In gas-solid regime, the reacting mixture consisted of toluene or acetonitrile, oxygen, nitrogen, and water vapour. The main degradation product of toluene was CO 2 with small amounts of benzaldehyde. In the presence of water vapour, the activity of TiO 2 Merck remained stable but greatly decreased if water was absent. TiO 2 Degussa P25 continuously deactivated, even in the presence of water vapour. With both catalysts, the photodegradation products of acetonitrile were CO 2 and HCN; the activity was stable and was independent of the presence of water vapour in the reacting mixture. The production of HCN represents a drawback of acetonitrile photocatalytic degradation but the elimination of HCN is not actually a problem. In liquid-solid regime, the main intermediates of toluene photodegradation were p -cresol and benzaldehyde; traces of pyrogallol and benzyl alcohol were also found. Benzoic acid, hydroquinone, and trans, trans muconic acid were detected only when TiO 2 Merck was used. The photodegradation products of acetonitrile were cyanide, cyanate, formate, nitrate, and carbonate ions.

  11. 2-{[2-Methyl-3-(2-methylphenyl-4-oxo-3,4-dihydroquinazolin-8-yl]oxy}acetonitrile

    Adel S. El-Azab

    2012-07-01

    Full Text Available In the title compound, C18H15N3O2, the fused ring system is almost planar [the dihedral angle between the six-membered rings is 1.81 (6°]. The 2-tolyl ring is approximately orthogonal to this plane [dihedral angle = 83.03 (7°] as is the acetonitrile group [C—O—C—C torsion angle = 79.24 (14°] which is also syn to the methyl substituent of the tolyl group. In the crystal, supramolecular layers are formed in the bc plane mediated by C—H...O, C—H...N and C—H...π interactions. The tolyl group is disordered over two positions in a 0.852 (3:0.148 (3 ratio.

  12. Microchip electrospray: cone-jet stability analysis for water-acetonitrile and water-methanol mobile phases.

    Jung, Stephanie; Effelsberg, Uwe; Tallarek, Ulrich

    2011-03-25

    Changes in mobile phase composition during high performance liquid chromatography (HPLC) gradient elution coupled to mass spectrometry (MS) sensitively affect electrospray operation modes. In this work, we identify the influences of dynamic changes in bulk conductivity on the cone-jet stability island for aqueous acetonitrile and aqueous methanol mobile phases commonly used in reversed-phase HPLC. Bulk conductivities of the mobile phases were varied by adding different amounts of formic acid. A commercial microchip-HPLC/ESI-MS configuration was modified to enable in situ electrospray diagnostics by frequency analysis of the microchip emitter current and spray imaging. This approach facilitated the detection of different spray modes together with their onset potentials. The established spray modes are described and the differences in onset potentials and stability regions explained by the physicochemical properties of the electrosprayed liquid. PMID:21333298

  13. Solution enthalpy of lithium perchlorate in diethyl ether, acetone, acetonitrile, dimethyl sulfoxide and effects of cycloaddition reactions acceleration

    Integral solution enthalpies of lithium perchlorate in diethyl ether, acetonitrile, acetone and DMSO at 298,2 K are determined calorimetrically; they are equal to -6.2, -9.1, -15.9 and -18.0 kcal/mol correspondingly. For diethyl ether dependence of integral solution enthalpy on salt concentration within the range from 3 x 10-3 up to 5,6 mol/l is determined. Reducing exoeffect of salt dissolution in the ether from -6 up to -5 kcal/mol in the range of small concentrations (3 x 10-3 - 3 x 10-2 mol/l), the constancy of the effect in the 5 x 10-2 - 1.3 mol/l range and following smooth reducing exoeffect up to -3.2 kcal/mol at salt concentration 5.6 mol/l is pointed out

  14. Studies on the nuances of the electrochemically induced room temperature isomerization of cis-stilbene in acetonitrile and ionic liquids.

    Abdul-Rahim, Omar; Simonov, Alexandr N; Boas, John F; Rüther, Thomas; Collins, David J; Perlmutter, Patrick; Bond, Alan M

    2014-03-20

    Electrochemical reduction of cis-stilbene occurs by two well-resolved one-electron reduction steps in acetonitrile with (n-Bu)4NPF6 as the supporting electrolyte and in N-butyl-N-methylpyrrolidinium (Pyrr1,4(+)) and (trimethylamine)(dimethylethylamine)-dihydroborate bis(trifluoromethylsulfonyl)amide (NTf2(-)) ionic liquids (ILs). Mechanistic details of the electroreduction have been probed by dc and Fourier transformed ac voltammetry, simulation of the voltammetry, bulk electrolysis, and EPR spectroscopy. The first one-electron reduction induces fast cis to trans isomerization in CH3CN and ILs, most likely occurring via disproportionation of cis-stilbene radical anions and fast transformation of the cis-dianion to the trans-configuration. The second reduction process is chemically irreversible in CH3CN due to protonation of the dianion but chemically reversible in highly aprotic ILs under high cis-stilbene concentration conditions. Increase of the (n-Bu)4NPF6 supporting electrolyte concentration (0.01-1.0 M) in CH3CN induces substantial positive shifts in the potentials for reduction of cis-stilbene, consistent with strong ion pairing of the anion radical and dianion with (n-Bu)4N(+). However, protection by ion pairing against protonation of the stilbene dianions or electrochemically induced cis-trans-stilbene isomerization is not achieved. Differences in electrode kinetics and reversible potentials for cis-stilbene(0/•-) and trans-stilbene(0/•-) processes are less pronounced in the Pyrr1,4-NTf2 ionic liquid than in the molecular solvent acetonitrile. PMID:24558952

  15. Low-temperature growth of nitrogen-doped carbon nanofibers by acetonitrile catalytic CVD using Ni-based catalysts

    Iwasaki, Tomohiro; Makino, Yuri; Fukukawa, Makoto; Nakamura, Hideya; Watano, Satoru

    2016-06-01

    To synthesize nitrogen-doped carbon nanofibers (N-CNFs) at high growth rates and low temperatures less than 673 K, nickel species (metallic nickel and nickel oxide) supported on alumina particles were used as the catalysts for an acetonitrile catalytic chemical vapor deposition (CVD) process. The nickel:alumina mass ratio in the catalysts was fixed at 0.05:1. The catalyst precursors were prepared from various nickel salts (nitrate, chloride, sulfate, acetate, and lactate) and then calcined at 1073 K for 1 h in oxidative (air), reductive (hydrogen-containing argon), or inert (pure argon) atmospheres to activate the nickel-based catalysts. The effects of precursors and calcination atmosphere on the catalyst activity at low temperatures were studied. We found that the catalysts derived from nickel nitrate had relatively small crystallite sizes of nickel species and provided N-CNFs at high growth rates of 57 ± 4 g-CNF/g-Ni/h at 673 K in the CVD process using 10 vol% hydrogen-containing argon as the carrier gas of acetonitrile vapor, which were approximately 4 times larger than that of a conventional CVD process. The obtained results reveal that nitrate ions in the catalyst precursor and hydrogen in the carrier gas can contribute effectively to the activation of catalysts in low-temperature CVD. The fiber diameter and nitrogen content of N-CNFs synthesized at high growth rates were several tens of nanometers and 3.5 ± 0.3 at.%, respectively. Our catalysts and CVD process may lead to cost reductions in the production of N-CNFs.

  16. Factors influencing high voltage performance of coconut char derived carbon based electrical double layer capacitor made using acetonitrile and propylene carbonate based electrolytes

    Hu, Changzheng; Qu, Weiguo; Rajagopalan, Ramakrishnan; Randall, Clive

    2014-12-01

    Symmetric EDLCs made using high purity carbon electrodes derived from coconut char were tested using 1 M Tetraethylammonium hexafluorophosphate dissolved in two different solvents namely acetonitrile and propylene carbonate. The cell voltage of the capacitor made using propylene carbonate can be extended to 3.5 V and it exhibited good cycling and thermal stability upto 70 °C while the voltage was limited to below 3.0 V in acetonitrile. XPS analysis of the positive and negative electrodes of EDLCs post cycling showed that the primary degradation products were related to ring opening reactions in propylene carbonate based electrolytes while water played a key role in degradation of acetonitrile based EDLCs.

  17. Study of the mechanism of acetonitrile stacking and its application for directly combining liquid-phase microextraction with micellar electrokinetic chromatography.

    Sun, Jingru; Feng, Jing; Shi, Ludi; Liu, Laping; He, Hui; Fan, Yingying; Hu, Shibin; Liu, Shuhui

    2016-08-26

    Acetonitrile stacking is an online concentration method that is distinctive due to its inclusion of a high proportion of organic solvent in sample matrices. We previously designed a universal methodology for the combination of liquid-phase microextraction (LPME) and capillary electrophoresis (CE) using acetonitrile stacking and micellar electrokinetic chromatography (MEKC) mode, thereby achieving large-volume injection of the diluted LPME extractant and the online concentration. In this report, the methodology was extended to the analysis of highly substituted hydrophobic chlorophenols in wines using diethyl carbonate as the extractant. Additionally, the mechanism of acetonitrile stacking was studied. The results indicated that the combination of LPME and MEKC exhibited good analytical performance: with ∼40-fold concentration by LPME, a 20-cm (33% of the total length) sample plug injection of an eight-fold dilution of diethyl carbonate with the organic solvent-saline solution produced enrichments higher by a factor of 260-791. Limits of qualification ranged from 5.5 to 16.0ng/mL. Acceptable reproducibilities of lower than 1.8% for migration time and 8.6% for peak areas were obtained. A dual stacking mechanism of acetonitrile stacking was revealed, involving transient isotachophoresis plus pH-junction stacking. The latter was associated with a pH shift induced by the presence of acetonitrile. The pseudo-stationary phase (Brij-35) played an important role in reducing the CE running time by weakening the isotachophoretic migration of the analyte ions following Cl(-) ions. The combination of acetonitrile stacking and nonionic micelle-based MEKC appears to be a perfect match for introducing water-immiscible LPME extractants into an aqueous CE system and can thus significantly expand the application of LPME-CE in green analytical chemistry. PMID:27451260

  18. The role of water in the photocatalytic degradation of acetonitrile and toluene in gas-solid and liquid-solid regimes

    Leonardo Palmisano; Gianmario Martra; Giuseppe Marcì; Vittorio Loddo; Elisa García-López; Agatino Di Paola; Salvatore Coluccia; Vincenzo Augugliaro; Maurizio Addamo

    2006-01-01

    Photocatalytic degradation of acetonitrile and toluene was carried out both in gas-solid and in liquid-solid regimes by using commercial TiO2 samples (Merck and Degussa P25). The investigation was mainly aimed to study the influence of water present in the reaction environment on the mechanism and degradation rate of two probe molecules. In gas-solid regime, the reacting mixture consisted of toluene or acetonitrile, oxygen, nitrogen, and water vapour. The main degradation product of toluene w...

  19. The synthesis of N-[4-dimethylamino-1-butyl(1-13C)-N-nitrosobenzamide, an inhibitor of trypsin; cyanide does not exchange with acetonitrile

    The synthesis of N-[4-dimethylamino-1-butyl(1-13C)-N-nitrobenzamide, a powerful active-site-directed inhibitor of trypsin, is reported. An efficient use of 13C-cyanide ion was achieved in the reaction with 1-chloro-3-dimethylaminopropane, the first step of the synthesis. Acetonitrile was used as a co-solvent with water in that step; no evidence was found for cyanide ion exchange with acetonitrile. The earlier report of such an exchange appears to be in error; the formation of hydrocyanic acid under the reaction conditions can account for the observations. (Author)

  20. Spectrophotometric study on the proton transfer reaction between 2-amino-4-methylpyridine with 2,6-dichloro-4-nitrophenol in methanol, acetonitrile and the binary mixture 50% methanol + 50% acetonitrile

    Al-Ahmary, Khairia M.; Habeeb, Moustafa M.; Al-Obidan, Areej H.

    2016-02-01

    Proton transfer reaction between 2-amino-4-methylpyridine (2AMP) as the proton acceptor with 2,6-dichloro-4-nitrophenol (DCNP) as the proton donor has been investigated spectrophotometrically in methanol (MeOH), acetonitrile (AN) and a binary mixture composed of 50% MeOH and 50% AN (AN-Me). The composition of the complex has been investigated utilizing Job's and photometric titration methods to be 1:1. Minimum-maximum absorbance equation has been applied to estimate the formation constant of the proton transfer reaction (KPT) where it reached high values in the investigated solvent confirming its high stability. The formation constant recorded higher value in AN compared with MeOH and mixture of AN-Me. Based on the formation of stable proton transfer complex, a sensitive spectrophotometric method was suggested for quantitative determination of 2AMP. The Lambert-Beer's law was obeyed in the concentration range 0.5-8 μg mL- 1 with small values of limits of detection and quantification. The solid complex between 2AMP with DCNP has been synthesized and characterized by elemental analysis to be 1:1 in concordant with the molecular stoichiometry in solution. Further analysis of the solid complex was carried out using infrared and 1H NMR spectroscopy.

  1. A laser flash photolysis study on duroquinone in binary mixtures of ionic liquid [bmim]+[PF6]- and acetonitrile

    Room temperature ionic liquids (RTILs) are entirely composed of special organic cations and anions, which are liquid near room temperature. Owing to their desirable properties including nonvolatility, high polarity, high selectivity and ease of recycling, RTILs are regarded as suitable solvents for green chemistry,which have been used as reaction media for a number of organic synthesis reactions, catalysis, separation processes and polymerization. As a prototype of RTIL, 1-butyl-3-methylimidazolium hexafluorophosphate [bmim][PF6] has been used as medium in which some representative photochemical reactions have been previously studied in comparison with volatile organic compounds. It was found that molecular diffusion of solute was significantly retarded and lifetime of transient species was longer in the neat [bmim][PF6]. Laser flash photolysis experiments were carried out using a Nd:YAG laser that provides 266 and 355 nm laser pulse with a duration of 5 ns and a maximum energy of 80 mJ per pulse. Using duroquinone (DQ) as a probe molecule photochemical properties of the ionic liquid [bmim][PF6] and its binary mixed solutions with acetonitrile (MeCN) were investigated at an excitation wavelength of 355 nm by laser flash photolysis technique. Along with the increasing of the fraction of [bmim][PF6] in the mixture, the characteristic absorption peak of triplet excited state 3DQ* showed a blue shift of ca. 20 nm. It was found that the decay of 3DQ* under N2 atmosphere followed a mono-exponential kinetics. Its rate constant increased with xRTIL (VRTIL/VMeCN) before the critical point at xRTIL = 0.3; however, it decreased obviously with xRTIL after the critical point. The experimental results indicate that RTIL didn't react with 3DQ*, which is different from our previous study on anthraquinone in binary solutions of [bmim][PF6] and acetonitrile. In view of the experimental data, it can be concluded that the viscosity and phase transformation are dominant for the effects

  2. Analysis on market demand and production technologies of acetonitrile%乙腈市场需求情况与技术分析

    韩凤义; 白亮; 曹金朋; 张鹏

    2011-01-01

    The application and market demand of acetonitrile are presented, and the domestic and overseas advances in production technonlgies of acetonitrile are reviewed. Based on comparing with ammonolysis of acetic acid and ammoxidation of eth-anol, the synthesis of acetonitrile by ethanol dehydrogenation ammoniation is analyzed emphatically, owing to easily available and cheap raw materials, slight corrosion to equipment and by-produced hydrogen gas. In the long term, as long as the high efficient catalyst is developed, the industrial prospects of synthesis of acetonitrile by ethanol dehydrogenation amination will be more promising.%介绍了乙腈的用途及市场需求情况,综述了国内外合成乙腈的主要工艺方法,在与乙酸氨化路线、乙醇氨氧化路线对比分析的基础上,着重分析了乙醇脱氢氨化法合成乙腈技术,结果表明,用乙醇作为原料直接合成乙腈,原料相对易得、价格低廉,设备腐蚀性小,并且可以副产氢气.从长远来看,只要开发出高效的催化剂,乙醇脱氢氨化合成乙腈技术更有工业应用前景.

  3. Advance in Production of Acetonitrile and its Refining Process%乙腈生产及其精制工艺研究进展

    卢英俊; 孙小方; 潘海天

    2014-01-01

    Industrial production methods of acetonitrile are classified as indirect synthesis method and direct synthesis method. According to the different raw materials used in direct synthesis method, the merits and demerits, the maturity of the processes were discussed in this paper. It can be concluded that the processes of amination-dehydrogenation of ethanol and amination-dehydration of acetic acid can be used in industrial production of acetonitrile, for which are simple, high conversion rate, good selectivity, and the acetonitrile could be purified easily. However, the propylene ammoxidation by-product method is the indirect synthesis method, which is the primary source of industrial acetonitrile. In which, the main impurities purification methods were introduced, such as hydrocyanic acid, aldehydes and ketones, oxazole, allyl alcohol, a small amount of propionitrile and water, emphases on the purification methods of water-acetonitrile azeotrope. Finally, the by-product acetonitrile refining process and the new refining process were contrasted, and the industrial development of acetonitrile was also prospected.%乙腈的工业生产分为间接法和直接合成法两类。根据原料的不同,对直接合成法中各种方法的优劣及其工艺的成熟程度进行了重点讨论,认为乙醇氨化脱氢法、乙酸氨化脱水法工艺流程简单,转化率高,选择性好,乙腈易分离提纯,最具有工业前景;间接法为丙烯氨氧化副产法,是目前工业生产乙腈的主要来源,针对其杂质种类较多等特点,分别介绍了氢氰酸、醛酮、噁唑、丙烯醇、少量丙腈和水等主要杂质的提纯方法,重点对水与乙腈共沸物的提纯做了详细阐述。最后将副产乙腈的精制工艺与新型精制工艺进行了对比,并展望了我国乙腈工业的发展未来。

  4. Thermodynamic and transport properties of spiro-(1,1')-bipyrrolidinium tetrafluoroborate and acetonitrile mixtures: A molecular dynamics study

    Qing-Yin, Zhang; Peng, Xie; Xin, Wang; Xue-Wen, Yu; Zhi-Qiang, Shi; Shi-Huai, Zhao

    2016-06-01

    Organic salts such as spiro-(1,1')-bipyrrolidinium tetrafluoroborate ([SBP][BF4]) dissolved in liquid acetonitrile (ACN) are a new kind of organic salt solution, which is expected to be used as an electrolyte in electrical double layer capacitors (EDLCs). To explore the physicochemical properties of the solution, an all-atom force field is established on the basis of AMBER parameter values and quantum mechanical calculations. Molecular dynamics (MD) simulations are carried out to explore the liquid structure and physicochemical properties of [SBP][BF4] electrolyte at room temperature. The computed thermodynamic and transport properties match the available experimental results very well. The microscopic structures of [SBP][BF4] salt solution are also discussed in detail. The method used in this work provides an efficient way of predicting the properties of organic salt solvent as an electrolyte in EDLCs. Project supported by the National Natural Science Foundation of China (Grant Nos. 21476172 and 51172160), the National High Technology Research and Development Program of China (Grant No. 2013AA050905), and the Natural Science Foundation of Tianjin, China (Grant Nos. 12JCZDJC28400, 14RCHZGX00859, 14JCTPJC00484, and 14JCQNJC07200).

  5. Electrochemistry of ruthenium dioxide composite electrodes in diethylmethylammonium-triflate protic ionic liquid and its mixtures with acetonitrile

    Ruthenium dioxide electrodes store charge via faradaic reactions involving proton exchange with the electrolyte, thereby achieving very high specific capacitance values that make it a very interesting material for electrochemical capacitors. We demonstrated earlier that these faradaic reactions occur for RuO2 in non-aqueous electrolytes based on protic ionic liquids, but the specific capacitance were limited due to the high degree of crystallinity of the material prepared in thin films by thermal decomposition. In order to increase the specific capacitance and to evaluate the impact of proton transport and transfer in high load electrodes, RuO2 was prepared by a conventional sol-gel route and used as the active material in a composite electrode to evaluate its electrochemical response in the protic ionic liquid diethymethylammonium-trifluoromethanesulfonate (DEMA-TfO). Cyclic voltammetry was carried out in the pure DEMA-TfO as well as in mixtures of the ionic liquid with acetonitrile. The results showed a significant impact of the electrolyte viscosity and conductivity at high potential scan rates and a limitation of the proton transfer rate at low scan rates. The specific capacitance can be improved at low scan rates by increasing temperature, reaching a value of 338 F/g at 120 °C with a 2 mV/s scan rate. This value is by far the highest reported for RuO2 in a non-aqeuous electrolyte

  6. Molecular recognition of 4′-Nitrobenzo-15-crown-5 by bis(benzimidazolium)propane borontetrafluoride in acetonitrile

    Chaudhuri, Tandrima, E-mail: tanchem_bu@yahoo.co.in [Department of Chemistry, Dr. Bhupendranath Dutta Smriti Mahavidyalaya, Burdwan 713407 (India); Karmakar, Animesh [Department of Chemistry, Dr. Bhupendranath Dutta Smriti Mahavidyalaya, Burdwan 713407 (India); Ghosh, Sabari; Mukhopadhyay, Chhanda [Department of Chemistry, University of Calcutta, 92 APC Road, Kolkata 700009 (India); Pal, Sunanda [Department of Chemistry, Dr. Bhupendranath Dutta Smriti Mahavidyalaya, Burdwan 713407 (India); Banerjee, Manas [Department of Chemistry, The University of Burdwan, Golapbag, Burdwan 713104, West Bengal (India)

    2015-05-15

    ICT based ratiometric sensing due to H-bonding interaction among three different crown ethers (C): Dibenzo-24-crown-8 (DB24C8 or C1), Benzo-15-crown-5 (B15C5 or C2) and 4′-Nitrobenzo-15-crown-5 (4′–NB15C5 or C3) along with the axle bis(benzimidazolium)propane borontetrafluoride (BBIM-propane) (3a–3d) have been studied. The association were initially ascertained from isosbestic formation and later corroborated by iso-emissive formation where C3 fails to establish iso-emissive. Stoichiometry of adducts were 1:1 both in the ground as well as in excited state. The threading or external association was finally distinguished by Monte Carlo simulation and frontier molecular orbital interaction. - Highlights: • The first report of ICT–based wavelength ratiometric interaction of crown–axle system. • Photophysical recognition of 4′-Nitrobenzo-15-crown-5 (4′-NB15C5 or C3) in acetonitrile. • Evidence of charge transfer interaction along with H-bond formation even in excited state is reported. • Monte Carlo simulation and FMO interaction justified the experimental findings.

  7. A study on fluorescence quenching of LD-425 by aromatic amines in 1,4-dioxane–acetonitrile mixtures

    The fluorescence quenching of 4-methyl-7-(4-morpholiny)-2H-pyrano[2,3-b]pyridin-2-one (LD-425) by aromatic amines aniline (AN), dimethyl aniline (DMAN) and diethyl aniline (DEAN) in solvent mixtures of 1,4-dioxane and acetonitrile has been studied at room temperature by steady-state and time-resolved methods. The positive deviation from linearity has been observed in the Stern–Volmer (S–V) plots. Various quenching rate parameters have been determined using the extended S–V equation and are found to be dependent on solvent polarity. The quenching ability of amines increases with increase in their ionization energies. Further, with the use of the sphere of action static quenching model and finite sink approximation model, it is concluded that the bimolecular quenching reactions are due to the presence of both dynamic and static quenching processes. - Graphical abstract: 4-methyl-7-(4-morpholiny)-2H-pyrano[2,3-b]pyridin-2-one (LD-425) Highlights: ► S–V plots of LD-425 show positive deviation in DIO–ACN solvent mixtures with all aromatic amines. ► r>R and kq>4πN′R′D indicate that quenching reactions are due to static quenching with diffusion limited. ► The time resolved measurements indicate the presence of the dynamic quenching process. ► The increase in kq with dielectric constant of solvents indicates the charge transfer character. ► Quenching efficiency increasing with amines ionization energies shows electron transfer nature.

  8. A ferrocene functionalized polymer: Poly [N-(ferrocenylmethyl)-o-phenylenediamine]. Electrochemical production and spectroelectroelectrochemical investigation in acetonitrile medium

    An electroactive and conductive polymer having pendant ferrocene units was prepared from the electrochemical polymerization of the synthesized monomer, N-(ferrocenylmethyl)-o-phenylenediamine in 0.1 M tetrabuthylammonium perchlorate/acetonitrile medium. The poly-N-(ferrocenylmethyl)-o-phenylenediamine (poly-FMOPD) was generated potentiodynamically or potentiostatically at both of indium tin oxide coated glass substrate and Pt electrodes. The poly-FMOPD film was characterized by cyclic voltammetry, chronoamperometry, electrochemical impedance spectroscopy, dry conductivity measurements, ultraviolet–visible absorption spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy. The electrical conductivity of polymer films was determined as 1.0 × 10−1 and 4 × 10−2 S cm−1 depending on the potential scanning range during electropolymerization. The electroactivity of the polymer film retained even after hundreds cycles between their reduced and oxidized states. The spectroelectrochemical analysis demonstrated that the polymer film reveals a reversible cycling with distinctive color changes between neutral and reduced/oxidized forms. For the polymer film, the maximum optical contrasts (ΔT%) were measured as 18% at and 37% at 480 nm by step the potential between (0.00 V)-(1.20 V) and (− 0.50 V)-(− 1.70 V), respectively. The optical energy band gaps as the onset energy for the π–π* transitions are calculated as 1.89 eV, 1.85 eV and 1.88 eV for the neutral, reduced and oxidized states of poly-FMOPD. - Highlights: • The ferrocene functionalized monomer and its polymer were synthesized electrochemically. • Spectroelectrochemical investigations were performed. • The polymer film showed reversible color changes between different redox forms. • It was found that the polymer film is conductive

  9. Acetonitrile extraction and dual-layer solid phase extraction clean-up for pesticide residue analysis in propolis.

    Oellig, Claudia

    2016-05-01

    Propolis is a very complex mixture of substances that is produced by honey bees and is known to be a rather challenging matrix for residue analysis. Besides resins, flavonoids and phenols, high amount of wax is co-extracted resulting in immense matrix effects. Therefore a suitable clean-up is crucial and indispensable. In this study, a reliable solid phase extraction (SPE) clean-up was developed for pesticide residue analysis in propolis. The clean-up success was quickly and easily monitored by high-performance thin-layer chromatography with different detection possibilities. The final method consists of the extraction of propolis with acetonitrile according to the QuEChERS method followed by an effective extract purification on dual-layer SPE cartridges with spherical hydrophobic polystyrene-divinylbenzene resin/primary secondary amine as sorbent and a mixture of toluene/acetone (95:5, v/v) for elution. Besides fat-soluble components like waxes, flavonoids, and terpenoids, more polar compounds like organic acids, fatty acids, sugars and anthocyanins were also removed to large extent. Method performance was assessed by recovery experiments at spiking levels of 0.5 and 1mg/kg (n=5) for fourteen pesticides that are relevant for propolis. Mean recoveries determined by HPLC-MS against solvent standards were between 40 and 101%, while calculation against matrix-matched standards provided recoveries of 79-104%. Precision of recovery, assessed by relative standard deviations, were below 9%. Thus, the developed dual-layer SPE clean-up enables the reliable pesticide residue analysis in propolis and provides a suitable alternative to time-consuming clean-up procedures proposed in literature. PMID:27059398

  10. Physico-chemical properties of non-newtonian shear thickening diisopropyl-ethylammonium-based protic ionic liquids and their mixtures with water and acetonitrile

    Johan JACQUEMIN; Anouti, M.; Lemordant, D.

    2011-01-01

    New protic ionic liquids (PILs) based on the diisopropyl-ethylammonium cation have been synthesized through a simple and atom-economic neutralization reaction between the diisopropyl-ethylamine and selected carboxylic acid. Densities and rheological properties were then measured for two original diisopropyl-ethylammonium-based protic ionic liquids (heptanoate and octanoate) at 298.15 K and atmospheric pressure. The effect of the presence of water or acetonitrile on the measured values was als...

  11. Polyethylene Glycols as Efficient Media for Decarboxylative Nitration of α,β-Unsaturated Aromatic Carboxylic Acids by Ceric Ammonium Nitrate in Acetonitrile Medium: A Kinetic and Mechanistic Study

    K.Ramesh; S. Shylaja; K. C. Rajanna; P. Giridhar Reddy; P. K. Saiprakash

    2013-01-01

    Polyethylene glycols (PEGs) were found to be efficient media for decarboxylative nitration of α,β-unsaturated aromatic carboxylic acids by ceric ammonium nitrate (CAN) in acetonitrile to give β-nitrostyrene derivatives. Kinetics of the reaction exhibited second order kinetics with a first order dependence on [CAN] and [substrate]. Reactions were too sluggish to be studied in the absence of PEG; therefore detailed kinetics were not taken up. Reaction times were reduced from 24 hrs to few hours...

  12. Physics and chemistry of lithium halides in 1,3-dioxolane and its binary mixtures with acetonitrile probed by conductometric, volumetric, viscometric, refractometric and acoustic study

    Highlights: ► Lithium halide interaction in binary mixture of acetonitrile and 1,3-dioxolane. ► Triple-ion formation in 1,3-dioxolane. ► More ion–solvent interaction than ion–ion interaction in all the solvent mixture. ► Ion solvation is due to preferential solvation and dimerization of acetonitrile. - Abstract: Electrolytic conductance (Λ), density (ρ), viscosity (η), refractive index (nD) and ultrasonic speed (u) of lithium halides LiX (where X = Cl, Br, I) have been studied in different mass fraction (w1 = 0.00–0.75) of acetonitrile (ACN) + 1,3-dioxolane (1,3-DO) mixtures at 298.15 K. The limiting molar conductivity (Λ0), association constant (KA), and distance of closest approach of ions (R) have been evaluated using Fuoss-conductance equation (1978). The deviation of conductometric curve (Λ vs √c) from linearity in 1,3-DO, analyzed by the Fuoss–Kraus theory. The limiting apparent molar volume (φV0), experimental slope (SV*) derived from Masson equation, and viscosity B and A-coefficients derived from Jones–Dole equation supplemented with density and viscosity data, respectively, have been interpreted in terms of ion–solvent and ion–ion interactions. The limiting partial molar adiabatic compressibility (φK0), have also been obtained from the value of ultrasonic speed (u) and discussed them to interpret the same.

  13. Cathodic electrochemical deposition of Magnéli phases TinO2n−1 thin films at different temperatures in acetonitrile solution

    Highlights: • TiOx films were prepared by cathodic electrodeposition in acetonitrile. • One-step electrodeposition of TiOx films without heat treatment process. • Different crystalline TinO2n−1 films (γTi3O5, λTi3O5, Ti4O7, Ti5O9) were obtained. - Abstract: The Magnéli phase titanium oxide films prepared by cathodic electrodeposition on indium–tin-oxide coated glass substrates from saturated peroxo-titanium solution in acetonitrile. Electrodeposited brownish semi-conductor thin films were identified via X-ray diffraction, Raman spectroscopy, UV–vis spectroscopy and scanning electron microscopy (SEM). The effects of different potentials and temperatures on the crystallinity of the thin films have been discussed. Ti3O5, Ti4O7 and Ti5O9 as the most favorable forms of the TinO2n−1 were electrodeposited on ITO electrode at electrochemical deposition potentials and different temperatures. The present investigation reveals that the electrochemical deposition of crystalline TinO2n−1 films by a simple one-step electrodeposition method (without any heat treatment) in acetonitrile solution is possible and very promising as a preparation method for electrochemical applications

  14. Thermal Thiocyanate Ligand Substitution Kinetics of the Solar Cell Dye N719 by Acetonitrile, 3-Methoxypropionitrile, and 4-tert-Butylpyridine

    Nguyen, Thai Hoang; Minh, Ha; Lund, Torben

    2007-01-01

    The kinetics of the thiocyanate substitution of the solar cell sensitizer [Ru(Hdcbpy)B2B(NCS)B2B]P2-P, 2 (n-CB4BHB9B)B4BNP+)P, (HB2Bdcbpy = L = 2,2´-bipyridine-4,4´-dicarboxylic acid), known as N719, by acetonitrile, 3-methoxypropionitrile, and 4-tert-butylpyridine (4-TBP) have been determined in...... factor of 2-10; it thus may be used as an additive to prevent the thermal degradation of thiocyanate-based ruthenium complexes in DSSC solar cells....

  15. Thermodynamic Study of the Complexation of p-Isopropylcalix[6]arene with Cs+ Cation in Dimethylsulfoxide-Acetonitrile Binary Media

    Gholam Hossein Rounaghi; Saeid Ahmadzadeh; Anuar Kassim; Majid Rezayi

    2011-01-01

    The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide–acetonitrile (DMSO-AN) binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs)+ complex in all binary mixed solvents is 1:1. The stability of the complexes is affected by the composition of the binary solvent media and a non-linear behavior was o...

  16. Poly[bis­(acetonitrile-κN)di-μ-thio­cyanato-κ2 N,S;κ2 S,N-nickel(II)

    Wöhlert, Susanne; Jess, Inke; Näther, Christian

    2011-01-01

    In the title compound, [Ni(NCS)2(CH3CN)2] n , the NiII cation is coordinated by two N-bonded and two S-bonded thio­cyanate anions, as well as two acetonitrile mol­ecules in an octa­hedral NiN4S2 coordination mode. The asymmetric unit comprises one nickel cation, two thio­cyanate anions and two actonitrile mol­ecules. In the crystal, the NiII cations are connected by bridging thio­cyanate anions into a three-dimensional coordination network.

  17. Nanosolvation by acetonitrile and 18-crown-6 ether induce strongly different effects on the electron-capture induced dissociation of aromatic tripeptide cations in the gas phase

    MacLot, S.; Rangama, J.; Nielsen, Steen Brøndsted; Poully, J.-C.

    2013-01-01

    Experimental gas-phase Electron Capture-Induced Dissociation (ECID) coupled to mass-spectrometry has been performed on the doubly-protonated tripeptides Lys-Trp-Lys (KWK) and Lys-Tyr-Lys (KYK). In this report, we focus on the influence of non-covalent binding of two different molecules, acetonitr......Experimental gas-phase Electron Capture-Induced Dissociation (ECID) coupled to mass-spectrometry has been performed on the doubly-protonated tripeptides Lys-Trp-Lys (KWK) and Lys-Tyr-Lys (KYK). In this report, we focus on the influence of non-covalent binding of two different molecules......, acetonitrile and 18-crown-6 ether (CE), to these tripeptide cations on the relative probabilities of their main fragmentation channels (H loss, NH3 loss and N — Cα bond cleavage) after electron capture from sodium atoms. First, we recorded the spectra of bare peptide ions, and found that N — Cα bond cleavage...... by one and two molecules show that acetonitrile evaporation is almost complete a few microseconds after electron capture, whereas fragments nanosolvated by CE are abundant. This is consistent with the binding energy of these molecules to lysine-containing peptides, which is much higher for CE than...

  18. Facile electrochemical polymerization of 2-(thiophen-2-yl)furan and the enhanced capacitance properties of its polymer in acetonitrile electrolyte containing boron trifluoride diethyl etherate

    Highlights: • The low-potential polymerization of 2-(thiophen-2-yl)furan into polymer (PTFu) was reported. • The electrochemical performance of PTFu was studied in three different electrolytes. • The specific capacitance of PTFu electrode reached 392.0 F g−1 at 5 A g−1 and had 67.0% retention after 500 cycles. • The addition of boron trifluoride diethyl etherate into acetonitrile electrolyte benefited to enhance the specific capacitance and stability of PTFu electrode. - ABSTRACT: In this study, a new simple hybrid poly(2-(thiophen-2-yl)furan) (PTFu) was easily electrodeposited by direct anodic oxidation of 2-(thiophen-2-yl)furan in acetonitrile solution containing 0.1 M lithium perchlorate (LiClO4). The oxidation onset potential of 2-(thiophen-2-yl)furan monomer in this medium was measured to be 0.90 V, which was lower than those of thiophene (1.47 V) and furan (1.28 V). The structure and morphology of PTFu were characterized by Ultraviolet–visible spectroscopy, Fourier transform infrared spectroscopy, scanning electron microscopy, and thermal analysis. The electrochemical capacitance properties of PTFu electrode in three electrolytes were also investigated by cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscope techniques. The electrochemical results showed that the specific capacitance of PTFu electrode was enhanced to 392.0 F g−1 from 249.4 F g−1 at 5 A g−1 and the cycling stability was also enhanced to 67.0% retention from 25.5% retention after 500 cycles when the equivalent boron trifluoride diethyl etherate (BFEE) was added into the acetonitrile electrolyte. Furthermore, the PTFu electrode in ionic liquid 1-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6) showed a lower specific capacitance value (209.4 F g−1 at 5 A g−1) and an improved stability (67.6% retention after 600 cycles). These results indicated that the conducting polymers based on furan should be a promising electrode

  19. Artificial neural network modelling of retention of pesticides in various octadecylsiloxane-bonded reversed-phase columns and water-acetonitrile mobile phase

    Previously, retention of 26 pesticides in the reversed-phase column Gemini (Phenomenex) and water-acetonitrile mobile phase was modelled using a feed-forward artificial neural network (ANN) learned by error back-propagation, accounting for both the effect of solute structure and mobile phase composition. To this end, log Kow of solutes and four quantum chemical molecular descriptors (the dipole moment, the mean polarizability, the anisotropy of the polarizability and an hydrogen-bonding descriptor based on the atomic charges located on the acid and basic functional groups) and acetonitrile % (v/v) in the eluent (%ACN) were used as ANN inputs. The above ANN-based approach is here tested on further five similar octadecylsiloxane-bonded columns in water-acetonitrile mobile phase within the %ACN range 30-70%. A quite good predictive performance evaluated on three external solutes in the whole %ACN range is observed, prediction errors being lower than ±0.1 log k units or slightly higher although still within ±0.15 log k units. On the other hand, multilinear regression used in place of ANN provides a more diffuse and non-uniform residual distribution for all the investigated columns. ANN multiple-column retention prediction is attempted by adding to the above variables a column descriptor defined as the average retention of calibration solutes extrapolated to 100% water. This more general model is built using 16 solutes and five 5-μm columns in calibration, while its predictive performance is tested on the remaining 10 compounds. Under these conditions, prediction errors are generally within ±0.2 log k units regardless of the kind of column. The possibility of cross-column prediction is evaluated by column leave-one-out cross-validation within the five 5-μm stationary phases and on a 4-μm external column. This analysis reveals that accuracy of retention prediction for unknown solutes in unknown columns is acceptable provided that the external column is not very

  20. Diaqua-μ3-oxido-hexakis(μ2-trichloroacetato-κ2O:O′(trichloroacetato-κOtrichromium(III acetonitrile trisolvate

    Seik Weng Ng

    2008-09-01

    Full Text Available In the crystal structure of the title compound, [Cr3(C2Cl3O27O(H2O2]·3CH3CN, the trinuclear [Cr3O(H2O2(Cl3CCO27] molecule has an oxide O atom that is connected to one monodentate trichloroacetate-coordinated and two water-coordinated CrIII atoms, the three metal atoms forming the points of an equilateral triangle. Each of the six remaining carboxylate groups bridges a Cr–O–Cr fragment. The cluster interacts with the three solvent molecules through water–acetonitrile O—H...N hydrogen bonds. Adjacent clusters are linked by a water–carboxylate O—H...O hydrogen bond to give a helical chain. One of the CCl3 groups was found to be disordered over two positions, with the major component having a site-occupancy factor of 0.64 (1.

  1. Polyethylene Glycols as Efficient Media for Decarboxylative Nitration of α,β-Unsaturated Aromatic Carboxylic Acids by Ceric Ammonium Nitrate in Acetonitrile Medium: A Kinetic and Mechanistic Study

    K. Ramesh

    2013-01-01

    Full Text Available Polyethylene glycols (PEGs were found to be efficient media for decarboxylative nitration of α,β-unsaturated aromatic carboxylic acids by ceric ammonium nitrate (CAN in acetonitrile to give β-nitrostyrene derivatives. Kinetics of the reaction exhibited second order kinetics with a first order dependence on [CAN] and [substrate]. Reactions were too sluggish to be studied in the absence of PEG; therefore detailed kinetics were not taken up. Reaction times were reduced from 24 hrs to few hours. The catalytic activity was found to be in the increasing order PEG-300 > PEG-400 > PEG-600 > PEG-200. Mechanism of PEG-mediated reactions was explained by Menger-Portnoy's scheme as applied in micellar kinetics.

  2. On the formation of radical dications of protonated amino acids in a "microsolution" of water or acetonitrile and their reactivity towards the solvent

    Sørensen, M; Forster, JS; Hvelplund, P; Jørgensen, Thomas J. D.; Nielsen, SB; Tomita, S

    2001-01-01

    In high-energy collisions (50 keV) between O2 and protonated amino acids AH+, radical dications AH2+* are formed for A = Phe, His, Met, Tyr, and Trp. When solvated by water or acetonitrile (S), AH2+*(S)1,2 are formed for A = Arg, His, Met, Tyr, and Trp. The stability of the hydrogen-deficient AH2...... 5 micros. The ionization energy, IE, of TyrH+ is calculated to be 11.1 eV in agreement with an experimental measurement of 10.1+/-2.1 eV ([IE(CH3CN)+IE(Tyr)]/ 2); hydration further lowers the IE by 0.3 eV [IE(TyrH+(H2O) = 10.8 eV, calculated]. We estimate the ionization energies of TrpH+, HisH+, and...

  3. Colorimetric and fluorogenic recognition of Hg2+ and Cr3+ in acetonitrile and their test paper recognition in aqueous media with the aid of rhodamine based sensors.

    Patidar, Rajesh; Rebary, Babulal; Paul, Parimal

    2015-03-01

    Two new rhodamine derivatives (L1 and L2) were synthesized, characterized and their ion recognition property has been investigated. Both of the ionophores exhibit colorimetric and fluorogenic response for Hg(2+) and Cr(3+) ions among large number of alkali, alkaline earth and transition metal ions tested in acetonitrile. Detail studies on determination of binding constant, binding mode, reversibility of binding, lower detection limit have been carried out. Detection of metal ions in aqueous media has also been demonstrated by preparation of simple, convenient and disposable test paper sensors with two approaches viz. filter paper and membrane filter loaded with these ionophores. Both of these methods responded sharply to both the metal ions (Hg(2+) and Cr(3+)) in aqueous solution, detectable by bared-eye. For better sensing at low concentration of metal ions, reprecipitation followed by filtration enrichment of ligands on membrane filter was employed. PMID:25666715

  4. Ionic molar volumes in methanol mixtures with acetonitrile, N,N-dimethylformamide and propylene carbonate at T = 298.15 K

    Highlights: • Densities of electrolyte solutions in methanol mixtures were measured at T = 298.15 K. • Apparent molar volumes of sodium cation and iodide anion were determined. • TPTB as a calculation method was used. • Preferential solvation of ions by organic solvents was examined. - Abstract: The densities of dilute solutions of three electrolytes (NaI, NaBPh4 and Ph4PI) in methanol mixtures with propylene carbonate (PC), N,N-dimethylformamide (DMF) and acetonitrile (AN) have been measured by Anton Paar 5000 densimeter at T = 298.15 K. Apparent molar volumes, VΦ have been determined at an electrolyte concentration of 0.06 mol · kg−1 over the entire mixed solvent composition range. Single ionic apparent molar volumes of transfer, ΔtVΦ (ion) were calculated using the tetraphenylphosphonium tetraphenylborate (TPTB) assumption. The results are discussed in terms of ionic preferential solvation

  5. (Liquid + liquid) equilibrium in binary systems of isomeric C8 aliphatic monoethers with acetonitrile and its interpretation by the COSMO-SAC model

    The (liquid + liquid) solubility curves have been determined by a synthetic method for six binary mixtures of [acetonitrile + {heptyl methyl ether CH3OnC7H15, or ethyl hexyl ether C2H5OnC6H13, or pentyl propyl ether nC3H7OnC5H11, or isopentyl propyl ether nC3H7Oi C5H11, or dibutyl ether nC4H9OnC4H9, or butyl isobutyl ether nC4H9OiC4H9}]. The possibility of the COSMO-SAC model to account for the thermodynamic differences between these systems has been tested and the discussion on the influence of screening charge of ethers on the system properties was undertaken

  6. On-line concentration of neutral analytes by complexation and acetonitrile sweeping in nonionic microemulsion electrokinetic chromatography with direct ultraviolet detection.

    Cao, Jun; Yi, Ling; Li, Ping; Chang, Yan-Xu

    2009-07-17

    To separate and detect neutral solutes in nonionic microemulsion electrokinetic chromatography (MEEKC), a novel method was developed, combining complex formation and acetonitrile (ACN) sweeping. In this report, dynamic borate complexation and on-line sweeping occurred simultaneously during a run. The operating parameters which affected the performance of analyte sweeping in nonionic MEEKC were examined in terms of borate complexation, ACN content, Brij-35 concentration and sample plug length. In addition, the validation of the method included tests of the limit of detection, reproducibility and sensitivity enhancement. 60-110-Fold of magnitude improvement in detection sensitivity for model compounds (ginsenoside Rf, ginsenoside Rb2, ginsenoside Re) using Brij-35 microemulsion was demonstrated. Furthermore, the method was applied to the determination of glucosides in the plant extract. PMID:19524933

  7. Crystal structures of bis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III complexes containing an acetonitrile or monodentate thyminate(1− ligand

    Mika Sakate

    2016-04-01

    Full Text Available The crystal structures of bis[2-(pyridin-2-ylphenyl]rhodium(III complexes with the metal in an octahedral coordination containing chloride and acetonitrile ligands, namely (OC-6-42-acetonitrilechloridobis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III, [RhCl(C11H8N2(CH3CN] (1, thyminate(1− and methanol, namely (OC-6-42-methanol(5-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-ido-κN1bis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III, [Rh(C11H8N2(C5H5N2O2(CH3OH]·CH3OH·0.5H2O (2, and thyminate(1− and ethanol, namely (OC-6-42-ethanol(5-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-ido-κN1bis[2-(pyridin-2-ylphenyl-κ2N,C1]rhodium(III, [Rh(C11H8N2(C5H5N2O2(C2H5OH]·C2H5OH (3, are reported. The acetonitrile complex, 1, is isostructural with the IrIII analog. In complexes 2 and 3, the monodeprotonated thyminate (Hthym− ligand coordinates to the RhIII atom through the N atom, and the resulting Rh—N(Hthym bond lengths are relatively long [2.261 (2 and 2.252 (2 Å for 2 and 3, respectively] as compared to the Rh—N bonds in the related thyminate complexes. In each of the crystals of 2 and 3, the complexes are linked via a pair of intermolecular N—H...O hydrogen bonds between neighbouring Hthym− ligands, forming an inversion dimer. A strong intramolecular O—H...O hydrogen bond between the thyminate(1− and alcohol ligands in mutually cis positions to each other is also observed.

  8. Vapor pressures and activity coefficients of binary mixtures of 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide with acetonitrile and tetrahydrofuran

    Highlights: ► A new apparatus for the determination of VLE is presented. ► The first vapor pressures for binary mixtures containing aprotic solvents in IL are reported. ► Calculated activity coefficients and osmotic coefficients reveal a strong non-ideal behavior. ► A more detailed study of the highly diluted IL concentration range is necessary to test the Debye–Hückel law. - Abstract: A new apparatus for the determination of VLE has been constructed which works for absolute pressure measurements as well as for measuring differential pressures. The first results obtained are (vapor + liquid) equilibria (VLE) of binary mixtures containing acetonitrile or tetrahydrofuran and the ionic liquid (IL) 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide [EMIm][NTf2] by using the absolute pressures method. VLE measurements were carried out over the whole concentration range at four different temperatures between 293.15 K and 313.15 K. Activity coefficients (γ1) of the solvents in [EMIm][NTf2] and their osmotic coefficients (φ1) have been determined from the VLE data.

  9. Salting-out-assisted liquid-liquid extraction with acetonitrile for the determination of trimetazidine in rat plasma using liquid chromatography-mass spectrometry.

    Xiong, Xin; Yang, Li

    2015-02-01

    A high-throughout bioanalytical method based on salting-out-assisted liquid/liquid extraction (SALLE) method with acetonitrile and mass spectrometry-compatible salts followed by LC-MS/MS analysis of trimetazidine in rat plasma is presented. It required only 50 μL of plasma and allows the use of minimal volumes of organic solvents. The seamless interface of SALLE and LC-MS eliminated the drying-down step and the extract was diluted and injected into an LC-MS/MS system with a cycle time of 2.5 min/sample. The retention times of trimetazidine and IS were approximately 1.1 and 1.7 min, respectively. Calibration curves were linear over the concentration range of 0.1-100 ng/mL, which can be extended to 500 ng/mL by dilution. The intra- and inter-batch precision, accuracy and the relative standard deviation were all trimetazidine concentrations in rat plasma. PMID:24954771

  10. Application of the Kirkwood-Buff theory of solutions to acetonitrile + amide binary mixtures by using inversion procedure and regular solution theory

    Anil Kumar Nain

    2009-05-01

    The Kirkwood-Buff (K-B) integrals play an important role in characterizing the intermolecular interactions in liquid mixtures. These are represented by the K-B parameters, AA, BB, and AB, which reflect correlation between like-like and like-unlike species in the mixture. The K-B integrals of binary mixtures of acetonitrile (ACN) with formamide (FA), N,N-dimethylformamide (DMF), N-methylacetamide (NMA) and N,N-dimethylacetamide (DMA) at 298.15 K and at atmospheric pressure have been computed from the experimental data of ultrasonic speed and density. We have used the similar inverse procedure (as proposed by Ben-Naim) to compute the K-B Parameters of the mixtures, in which thermodynamic information on mixtures such as partial molar volumes, isothermal compressibility, and experimental data of partial vapour pressures are used. A new route has been incorporated by using regular solution theory in the computation of excess free energy for obtaining the partial vapour pressures of binary liquid mixtures. The low values of excess entropy ( ≈ 0) obtained for these mixtures indicate the applicability of regular solution theory to these mixtures. The results obtained regarding intermolecular interaction in all the four mixtures under study from this new procedure are in good agreement with those obtained from the trends exhibited by the excess functions of these mixtures.

  11. Investigations of acetonitrile solvent cluster formation in supercritical carbon dioxide, and its impact on microscale syntheses of carbon-11-labeled radiotracers for PET

    A new strategy has been developed for synthesizing positron emission tomography (PET) radiotracers using [11C]methyl iodide. This strategy relies on the ability of organic co-solvents to cluster within mixtures of supercritical fluids resulting in localized regions of high density which can serve as microscopic pockets for reaction. We've shown that acetonitrile will cluster about dilute solutes when mixtures of this co-solvent with carbon dioxide are forced to behave as a homogeneous fluid at the critical point. We applied this strategy in a systematic investigation of the conditions for optimized reaction between methyl iodide and L-α-methyl-N-2-propynyl phenethylamine (nordeprenyl) to yield L-deprenyl. Variables such as temperature, ultraviolet light exposure, co-solvent concentration, system pressure, and methyl iodide concentration were explored. The synthesis of radioactive [11C]-L-deprenyl using no-carrier-added concentrations of [11C]methyl iodide was also tested. Results showed that greater than 90% radiochemical yield of the desired product could be attained using 40 times less labeling substrate than in conventional PET tracer syntheses

  12. Conductance Studies on Complex Formation between c-Methylcalix[4]resorcinarene and Titanium (III in Acetonitrile-H2O Binary Solutions

    Naghmeh Saadati

    2013-09-01

    Full Text Available Calixresorcinarenes have proved to be unique molecules for molecular recognition via hydrogen bonding, hydrophobic and ionic interactions with suitable substrates such as cations. The study of the interactions involved in the complexation of different cations with calixresorcinarenes in solvent mixtures is important for a better understanding of the mechanism of biological transport, molecular recognition, and other analytical applications. This article summarizes different aspects of the complexes of the Ti3+ metal cation with c-methylcalix[4]resorcinarene (CMCR as studied by conductometry in acetonitrile (AN–water (H2O binary mixtures at different temperatures. Conductance data show that the metal cation/ligand (ML stoichiometry of the complexes in solution is 1:1 in all cases. Non-linear behaviour was observed for the variation of logKf of the complexes vs. the composition of the binary solvent mixtures. Selectivity of CMCR for the Ti3+ cation is sensitive to solvent composition; in some cases and at certain compositions of the mixed solvent systems, the selectivity order is changed. Values of thermodynamic parameters (, for formation of the CMCR–Ti3+ complexes in AN–H2O binary systems were obtained from the temperature dependence of stability constants, and the results show that the thermodynamics of complexation reactions are affected by the nature and composition of the mixed solvents.

  13. Non-ideality in Born-free energy of solvation in alcohol-water and dimethylsulfoxide-acetonitrile mixtures: Solvent size ratio and ion size dependence

    Hemant K Kashyap; Ranjit Biswas

    2007-09-01

    Recent extension of mean spherical approximation (MSA) for electrolyte solution has been employed to investigate the non-ideality in Born-free energy of solvation of a rigid, mono-positive ion in binary dipolar mixtures of associating (ethanol-water) and non-associating (dimethylsulfoxide-acetonitrile) solvents. In addition to the dipole moments, the solvent size ratio and ion size have been treated in a consistent manner in this extended MSA theory for the first time. The solvent-solvent size ratio is found to play an important role in determining the non-ideality in these binary mixtures. Smaller ions such as Li+ and Na+ show stronger non-ideality in such mixtures compared to bigger ions (for example, Cs+ and Bu4N+). The partial solvent polarization densities around smaller ions in tertiary butanol (TBA)-water mixture is found to be very different from that in other alcohol-water mixtures as well as to that for larger ions in aqueous solutions of TBA. Non-ideality is weaker in mixtures consisting of solvent species possessing nearly equal diameters and dipole moments and is reflected in the mole fraction dependent partial solvent polarization densities.

  14. Dual β-cyclodextrin functionalized Au@SiC nanohybrids for the electrochemical determination of tadalafil in the presence of acetonitrile.

    Yang, Long; Zhao, Hui; Li, Can-Peng; Fan, Shuangmei; Li, Bingchan

    2015-02-15

    This finding described the electrochemical detection of tadalafil based on CM-β-cyclodextrin and SH-β-cyclodextrin functionalized Au@SiC nanohybrids film. The tadalafil electrochemical signal could be dramatically amplified by introducing 40% of acetonitrile in buffer medium and further enhanced by the host-guest molecular recognition capacity of β-cyclodextrin. Uniform and monodispersed ~5.0 nm Au NPs were anchored on the SiC-NH2 surface via a chemical reduction process by using polyethylene glycol and sodium citrate as dispersant and stabilizing agent. CM-β-CD was covalently bound on Au@SiC by combining the amine group of SiC-NH2 with the carboxyl group of CM-β-CD with the aid of EDC/NHS coupling agent. SH-β-CD could tightly attach to the surface of Au@SiC by the strong coordinating capability between Au and thiol. Differential pulse voltammetry was successfully used to quantify tadalafil within the concentration range of 0.01-100 µM under optimal conditions with a detection limit (S/N = 3) of 2.5 nM. In addition, the β-CD-Au@SiC nanohybrid electrochemical sensor showed high selectivity to two other erectile dysfunction drugs sildenafil and vardenafil. The proposed electrochemical sensing platform was successfully used to determine tadalafil in raw materials, herbal sexual health products, and spiked human serum samples. PMID:25216449

  15. Conjugated and fluorescent polymer based on dansyl-substituted pyrrole prepared by electrochemical polymerization in acetonitrile containing boron trifluoride diethyl etherate

    Graphical abstract: - Highlights: • A fluorescent pyrrole derivative bearing a dansyl substituent (PyPDG) was synthesized. • PyPDG was electropolymerized onto ITO in (C4H9)4NBF4/CH3CN/BFEE mixed electrolyte. • The resulting polymer (PPyPDG) films displayed electrochromic behavior. • PPyPDG is a good green light emitter material. - Abstract: A fluorescent pyrrole derivative bearing a dansyl substituent was prepared by a simple synthetic route and electropolymerized onto Indium Tin Oxide (ITO) electrodes. The presence of the dansyl group in the monomer precursor prevents the electropolymerization in usual systems, such as (C4H9)4NBF4 in acetonitrile (CH3CN). For this reason, it was added 20% boron trifluoride diethyl etherate (BFEE) to this system, to achieve electropolymerization. The resulting poly[3-(N-pyrrolyl)propyl dansylglycinate] (PPyPDG) films displayed electrochromic behavior. Their color varied from greenish-yellow, in the neutral state, to greyish-green, in the oxidized state; moreover PPyPDG is a good green light emitter material. Therefore, PPyPDG films might be potentially applicable in displays and optoelectronic devices

  16. Optical properties and device characteristics of 2-(antipyrin-4-ylhydrazono)-2-(4-nitrophenyl)acetonitrile thin films for photodiode applications

    El-Menyawy, E. M.; Zedan, I. T.

    2015-02-01

    2-(Antipyrin-4-ylhydrazono)-2-(4-nitrophenyl)acetonitrile (AHNA) films were deposited via thermal evaporation technique. The optical properties of AHNA films and electrical characteristics of Au/AHNA/n-Si/Au heterojunction diode have been reported. The optical properties of AHNA films were investigated using the spectrophotometric measurements of optical transmittance and reflectance over spectral range 190-2500 nm. The films have indirect allowed optical band gap of 3.6 eV. The refractive index of the films was calculated and the dispersion parameters of the films were determined on the light of the single oscillator model. The electrical properties of Au/AHNA/n-Si/Au heterojunction diode were studied in terms of current-voltage characteristics. The device showed rectification behaviour with a rectification ratio of 100 at ±1 V. The conduction mechanisms and diode parameters such as ideality factor, barrier height and series resistance of the device were determined. The device under illumination showed photovoltaic properties. The short circuit current and open circuit voltage were found to be function of illumination intensity. The device satisfies the conditions to be used as photodiode.

  17. Increasing the energy density of the non-aqueous vanadium redox flow battery with the acetonitrile-1,3-dioxolane-dimethyl sulfoxide solvent mixture

    Herr, T.; Fischer, P.; Tübke, J.; Pinkwart, K.; Elsner, P.

    2014-11-01

    Different solvent mixtures were investigated for non-aqueous vanadium acetylacetonate (V(acac)3) redox flow batteries with tetrabutylammonium hexafluorophosphate as the supporting electrolyte. The aim of this study was to increase the energy density of the non-aqueous redox flow battery. A mixture of acetonitrile, dimethyl sulfoxide and 1-3-dioxolane nearly doubles the solubility of the active species. The proposed electrolyte system was characterized by Raman and FT-IR spectroscopy, cyclic voltammetry, electrochemical impedance spectroscopy and charge-discharge set-up. Spectroscopic methods were applied to understand the interactions between the solvents used and their impact on the solubility. The potential difference between oxidation and reduction of V(acac)3 measured by cyclic voltammetry was about 2.2 V. Impedance spectroscopy showed an electrolyte resistance of about 2400 Ω cm2. Experiments in a charge-discharge test cell achieved coulombic and energy efficiencies of ∼95% and ∼27% respectively. The highest discharge power density was 0.25 mW cm-2.

  18. Densities and volumetric properties of (acetonitrile+an amide) binary mixtures at temperatures between 293.15K and 318.15K

    The densities of binary mixtures of acetonitrile (ACN) with formamide (FA), N,N-dimethylformamide (DMF), N-methylacetamide (NMA), and N,N-dimethylacetamide (DMA), including those of pure liquids, over the entire composition range were measured at temperatures (293.15, 298.15, 303.15, 308.15, 313.15, and 318.15) K and atmospheric pressure. From the experimental data, the excess molar volume, VmE, and partial molar volumes, V-bar m,1 and V-bar m,2, were calculated over whole composition range. The variation of these parameters with composition and temperature of the mixtures has been discussed in terms of molecular interaction in these mixtures. The VmE values were found negative for all the mixtures and at each temperature studied, indicating the presence of specific interactions between ACN and amide molecules. The extent of negative deviations in VmE values follows the order: FA>NMA>DMA>DMF. It is observed that the VmE values depend upon the positions of methyl groups in these amide molecules

  19. Thermodynamic Study of the Complexation of p-Isopropylcalix[6]arene with Cs+ Cation in Dimethylsulfoxide-Acetonitrile Binary Media

    Gholam Hossein Rounaghi

    2011-09-01

    Full Text Available The complexation reactions between the macrocyclic ionophore, p-isopropylcalix[6]arene and Cs+ cation were studied in dimethylsulfoxide–acetonitrile (DMSO-AN binary non-aqueous solvents at different temperatures using a conductometry method. The conductance data show that the stoichiometry of the (p-isopropylcalix[6]-arene·Cs+ complex in all binary mixed solvents is 1:1. The stability of the complexes is affected by the composition of the binary solvent media and a non-linear behavior was observed for changes of log Kf of the complex versus the composition of the binary mixed solvents. The thermodynamic parameters (DH°c and DS°c for formation of (p-isopropyl-calix[6]arene·Cs+ complex were obtained from temperature dependence of the stability constant and the obtained results show that the (p-isopropylcalix[6]arene·Cs+ complex is enthalpy destabilized, but entropy stabilized, and the values of the mentioned parameters are affected strongly by the nature and composition of the binary mixed solvents.

  20. Quantification of volatile organic compounds in exhaled human breath. Acetonitrile as biomarker for passive smoking. Model for isoprene in human breath

    The topic of this thesis is the quantification of volatile organic compounds in human breath under various circumstances. The composition of exhaled breath reflects metabolic processes in the human body. Breath analysis is a non invasive technique which makes it most interesting especially for medical or toxicological applications. Measurements were done with Proton-Transfer-Reaction Mass-Spectrometry (PTR-MS). This technique combines the advantage of small fragmentation of chemical ionization with highly time resolved mass spectrometry. A big part of this work is about investigations of exposition due to tobacco smoke. After smoking cigarettes the initial increase and time dependence of some compounds in the human breath are monitored . The calculated decrease resulting only from breathing out the compounds is presented and compared to the measured decline in the breath. This allows the distinction whether breathing is the dominant loss of a compound or a different metabolic process remover it more efficiently. Acetonitrile measured in human breath is presented as a biomarker for exposition to tobacco smoke. Especially its use for quantification of passive smoking, the exposition to environmental tobacco smoke (ETS) is shown. The reached accuracy and the fast way of measuring of acetonitrile in human breath using PTR-MS offer a good alternative to common used biomarkers. Numerous publications have described measurements of breath isoprene in humans, and there has been a hope that breath isoprene analyses could be a non-invasive diagnostic tool to assess serum cholesterol levels or cholesterol synthesis rate. However, significant analytical problems in breath isoprene analysis and variability in isoprene levels with age, exercise, diet, etc. have limited the usefulness of these measurements. Here, we have applied proton-transfer-reaction mass spectrometry (PTR-MS) to this problem, allowing on-line detection of breath isoprene. We show that breath isoprene

  1. Probing structural patterns of ion association and solvation in mixtures of imidazolium ionic liquids with acetonitrile by means of relative (1)H and (13)C NMR chemical shifts.

    Marekha, Bogdan A; Kalugin, Oleg N; Bria, Marc; Idrissi, Abdenacer

    2015-09-21

    Mixtures of ionic liquids (ILs) with polar aprotic solvents in different combinations and under different conditions (concentration, temperature etc.) are used widely in electrochemistry. However, little is known about the key intermolecular interactions in such mixtures depending on the nature of the constituents and mixture composition. In order to systematically address the intermolecular interactions, the chemical shift variation of (1)H and (13)C nuclei has been followed in mixtures of imidazolium ILs 1-n-butyl-3-methylimidazolium tetrafluoroborate (BmimBF4), 1-n-butyl-3-methylimidazolium hexafluorophosphate (BmimPF6), 1-n-butyl-3-methylimidazolium trifluoromethanesulfonate (BmimTfO) and 1-n-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide (BmimTFSI) with molecular solvent acetonitrile (AN) over the entire composition range at 300 K. The concept of relative chemical shift variation is proposed to assess the observed effects on a unified and unbiased scale. We have found that hydrogen bonds between the imidazolium ring hydrogen atoms and electronegative atoms of anions are stronger in BmimBF4 and BmimTfO ILs than those in BmimTFSI and BmimPF6. Hydrogen atom at position 2 of the imidazolium ring is substantially more sensitive to interionic hydrogen bonding than those at positions 4-5 in the case of BmimTfO and BmimTFSI ILs. These hydrogen bonds are disrupted upon dilution in AN due to ion dissociation which is more pronounced at high dilutions. Specific solvation interactions between AN molecules and IL cations are poorly manifested. PMID:26278514

  2. The mixed-valent copper thiolate complex hexakis{μ3-2-[(1,3-dimethylimidazolideneamino]benzenethiolato}dicopper(IItetracopper(I bis(hexafluoridophosphate acetonitrile disolvate dichloromethane disolvate

    Adam Neuba

    2013-01-01

    Full Text Available The molecular structure of the title compound, [Cu4ICu2II(C11H14N3S6](PF62·2CH3CN·2CH2Cl2, shows a mixed-valent copper(I/II thiolate complex with a distorted tetrahedral coordination of the CuI and CuII cations by one guanidine N atom and three S atoms each. Characteristic features of the Cu6S6 skeleton are a total of six chemically identical μ3-thiolate bridges and almost planar Cu2S2 units with a maximum deviation of 0.110 (1 Å from the best plane. Each Cu2S2 unit then shares common Cu–S edges with a neighbouring unit; the enclosed dihedral angle is 60.14 (2°. The geometric centre of the Cu6S6 cation lies on a crystallographic inversion centre. Cu—S bond lengths range from 2.294 (1 to 2.457 (1 Å, Cu—N bond lengths from 2.005 (3 to 2.018 (3 Å and the non-bonding Cu...Cu distances from 2.5743 (7 to 2.5892 (6 Å. C—H...F hydrogen-bond interactions occur between the PF6− anion and the complex molecule and between the PF6− anion and the acetonitrile solvent molecule.

  3. (2,2′-Bipyridinechlorido[diethyl (2,2′:6′,2′′-terpyridin-4-ylphosphonate]ruthenium(II hexafluoridophosphate acetonitrile/water solvate

    Weizhong Chen

    2013-09-01

    Full Text Available The cationic complex in the title compound, [RuCl(C10H8N2(C19H20N3O3P]PF6·0.83CH3CN·0.17H2O, is a water-oxidation precatalyst functionalized for TiO2 attachment via terpyridine phosphonate. The The RuII atom in the complex has a distorted octahedral geometry due to the restricted bite angle [159.50 (18°] of the terpyridyl ligand. The dihedral angle between the least-squares planes of the terpyridyl and bipyridyl moieties is 86.04 (14°. The mean Ru—N bond length for bipyridine is 2.064 (5 Å, with the bond opposite to Ru—Cl being 0.068 Å shorter. For the substituted terpyridine, the mean Ru—N distance involving the outer N atoms trans to each other is 2.057 (6 Å, whereas the bond length involving the central N atom is 1.944 (5 Å. The Ru—Cl distance is 2.4073 (15 Å. The P atom of the phosphonate group lies in the same plane as its adjacent pyridyl ring, with the ordinary character of the bond between P and Ctpy [1.801 (6 Å] allowing for free rotation of the terpyridine substituent around the P—Ctpy axis. The acetonitrile solvent molecule was refined to be disordered with two water molecules; occupancies for the acetontrile and water molecules were 0.831 (9 and 0.169 (9, respectively. Also disordered was the PF6− counter-ion (over three positions and one of the ethoxy substituents (with two positions. The crystal structure shows significant intra- and intermolecular H...X contacts, especially some involving the Cl− ligand.

  4. Effects of ionic liquid [bmim][PF6] on absorption spectra and reaction kinetics of the duroquinone triplet state in acetonitrile.

    Zhu, Guanglai; Wu, Guozhong; Sha, Maolin; Long, Dewu; Yao, Side

    2008-04-10

    The transient absorption spectra and photoinduced electron-transfer process of duroquinone (DQ) in mixed binary solutions of ionic liquid (IL) [bmim][PF6] and acetonitrile (MeCN) have been investigated by laser photolysis at an excitation wavelength of 355 nm. A spectral blue shift of 3DQ* was observed in the IL/MeCN mixtures compared to MeCN. At lower VIL(volume fraction of IL), the interaction between DQ and the solvent is dominant, and the decay rate constant (kobs) of 3DQ* increases steadily with the increasing of VIL; to the contrary, at higher VIL, the network structures due to the hydrogen bond and viscosity are dominant, and the decay rate constant decreases obviously with increasing VIL. A critical point (turnover) was observed at VIL = approximately 0.30. The dependence of the observed growth rate (kgr) of the photoinduced electron-transfer (PET) products on VIL is complex and shows a special change; kgr first decreases with increasing VIL, then increases, and finally decreases slowly with further increasing of VIL. It is speculated that the PET process in the mixture can be affected by factors including the local structure and the reorganization energy of the solvent and salt and cage effects. The change of local structure of [bmim][PF6]/MeCN is supported by following the steady-state fluorescence behavior of the mixture, in combination with the molecular dynamics simulation of the thermodynamic property. The results revealed that the degree of self-aggregation of monomeric cations (bmim+) to associated forms increases with increasing VIL. This is in good agreement with the laser photolysis results for the same solutions. PMID:18331005

  5. Terahertz Frequency-Domain Spectroscopy of Low-Pressure Acetonitrile Gas by a Photomixing Terahertz Synthesizer Referenced to Dual Optical Frequency Combs

    Hsieh, Yi-Da; Kimura, Hiroto; Hayashi, Kenta; Minamikawa, Takeo; Mizutani, Yasuhiro; Yamamoto, Hirotsugu; Iwata, Tetsuo; Inaba, Hajime; Minoshima, Kaoru; Hindle, Francis; Yasui, Takeshi

    2016-05-01

    A terahertz (THz) frequency synthesizer based on photomixing of two near-infrared lasers with a sub-THz to THz frequency offset is a powerful tool for spectroscopy of polar gas molecules due to its broad spectral coverage; however, its frequency accuracy and resolution are relatively low. To tune the output frequency continuously and widely while maintaining its traceability to a frequency standard, we developed a photomixing THz synthesizer phase-locked to dual optical frequency combs (OFCs). While the phase-locking to dual OFCs ensured continuous tuning within a spectral range of 120 GHz, in addition to the traceability to the frequency standard, use of a broadband uni-traveling carrier photodiode for photomixing enabled the generation of CW-THz radiation within a frequency range from 0.2 to 1.5 THz. We demonstrated THz frequency-domain spectroscopy of gas-phase acetonitrile CH3CN and its isotope CH3 13CN in the frequency range of 0.600-0.720 THz using this THz synthesizer. Their rotational transitions were assigned with a frequency accuracy of 8.42 × 10-8 and a frequency resolution of 520 kHz. Furthermore, the concentration of the CH3CN gas at 20 Pa was determined to be (5.41 ± 0.05) × 1014 molecules/cm3 by curve fitting analysis of the measured absorbance spectrum, and the mixture ratio of the mixed CH3CN/CH3 13CN gas was determined to be 1:2.26 with a gas concentration of 1014-1015 molecules/cm3. The developed THz synthesizer is highly promising for high-precision THz-FDS of low-pressure molecular gases and will enable the qualitative and quantitative analyses of multiple gases.

  6. Identification and separation of the organic compounds in coal-gasification condensate waters. [5,5 dimethyl hydantoin, dihydroxy benzenes, acetonitrile

    Mohr, D.H. Jr.; King, C.J.

    1983-08-01

    A substantial fraction of the organic solutes in condensate waters from low-temperature coal-gasification processes are not identified by commonly employed analytical techniques, have low distriution coefficients (K/sub C/) into diisopropyl ether (DIPE) or methyl isobutyl ketone (MIBK), and are resistant to biological oxidation. These compounds represent an important wastewater-treatment problem. Analytical techniques were developed to detect these polar compounds, and the liquid-liquid phase equilibria were measured with several solvents. A high-performance liquid - chromatography (HPLC) technique was employed to analyze four condensate-water samples from a slagging fixed-bed gasifier. A novel sample-preparation technique, consisting of an azeotropic distillation with isopropanol, allowed identification of compounds in the HPLC eluant by combined gas chromatography and mass spectrometry. 5,5-dimethyl hydantoin and related compounds were identified in condensate waters for the first time, and they account for 1 to 6% of the chemical oxygen demand (COD). Dimethyl hydatoin has a K/sub D/ of 2.6 into tributyl phosphate (TBP) and much lower K/sub D/ values into six other solvents. It is also resistant to biological oxidation. Phenols (59 to 76% of the COD), dihydroxy benzenes (0.02 to 9.5% of the COD), and methanol, acetonitrile, and acetone (15% of the COD in one sample) were also detected. Extraction with MIBK removed about 90% of the COD. MIBK has much higher K/sub D/ values than DIPE for dihydroxy benzenes. Chemical reactions occurred during storage of condensate-water samples. The reaction products had low K/sub D/ values into MIBK. About 10% of the COD had a K/sub D/ of nearly zero into MIBK. These compounds were not extracted by MIBK over a wide range of pH. 73 references, 6 figures, 35 tables.

  7. Thermodynamics of the amalgam cells {M-Amalgam|MCl or MCl2 (m)|AgCl|Ag} (M=Rb, Cs, Sr, Ba) and primary medium effects in (acetonitrile + water)

    The potential difference E of the amalgam cell {MxHg1-x|MCl or MCl2 (m)| AgCl |Ag} (M=Rb, Cs, Sr, Ba) has been measured as a function of the mole fraction xM of M metal in amalgams and of the molality m of MCl (or MCl2) in (acetonitrile [A] + water [W]) solvent mixtures containing up to acetonitrile mass fraction wA=0.50, at T=298.15 K. The respective molal-scale standard potential differences E0m have been determined together with the relevant activity coefficients γ± functions of the MCl (or MCl2) molality. The E0m dependence on the mole fraction xA of acetonitrile in the solvent mixture within the range explored turns out to be linear for all the four metals M in the amalgams considered. Of course, also the difference ([E0m]W-[E0m]A), which is a measure of the primary medium effect upon transferring MCl (or MCl2) from pure water [W] to the acetonitrile [A] mixture, is linear in xA. In this context, following Feakins and French's scheme, which implies volume fraction statistics, analysis of the relevant mol · dm-3 scale primary medium effects, i.e., ([E0c]W-[E0c]A), upon MCl (or MCl2), as a linear function of the logarithm of water volume fraction, would lead to primary hydration numbers of 4.2 for RbCl, 4.0 for CsCl, 10.7 for SrCl2, and 10.3 for BaCl2, respectively, in acceptable agreement with literature data by Bockris based on different methods

  8. Multiresidue pesticide analysis of ginseng powders using acetonitrile- or acetone-based extraction, solid-phase extraction cleanup, and gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM) or -tandem mass spectrometry (GC-MS/MS).

    Wong, Jon W; Zhang, Kai; Tech, Katherine; Hayward, Douglas G; Krynitsky, Alexander J; Cassias, Irene; Schenck, Frank J; Banerjee, Kaushik; Dasgupta, Soma; Brown, Don

    2010-05-26

    A multiresidue method for the analysis of 168 pesticides in dried powdered ginseng has been developed using acetonitrile or acetone mixture (acetone/cyclohexane/ethyl acetate, 2:1:1 v/v/v) extraction, solid-phase extraction (SPE) cleanup with octyl-bonded silica (C(8)), graphitized carbon black/primary-secondary amine (GCB/PSA) sorbents and toluene, and capillary gas chromatography-mass spectrometry/selective ion monitoring (GC-MS/SIM) or -tandem mass spectrometry (GC-MS/MS). The geometric mean limits of quantitation (LOQs) were 53 and 6 microg/kg for the acetonitrile extraction and 48 and 7 microg/kg for the acetone-based extraction for GC-MS/SIM and GC-MS/MS, respectively. Mean percent recoveries and standard deviations from the ginseng fortified at 25, 100, and 500 microg/kg using GC-MS/SIM were 87 +/- 10, 88 +/- 8, and 86 +/- 10% from acetonitrile extracts and 88 +/- 13, 88 +/- 12, and 88 +/- 14% from acetone mixture extracts, respectively. The mean percent recoveries from the ginseng at the 25, 100, and 500 microg/kg levels using GC-MS/MS were 83 +/- 19, 90 +/- 13, and 89 +/- 11% from acetonitrile extracts and 98 +/- 20, 91 +/- 13, and 88 +/- 14% from acetone extracts, respectively. Twelve dried ginseng products were found to contain one or more of the following pesticides and their metabolites: BHCs (benzene hexachlorides, alpha-, beta-, gamma-, and delta-), chlorothalonil, chlorpyrifos, DDT (dichlorodiphenyl trichloroethane), dacthal, diazinon, iprodione, quintozene, and procymidone ranging from 4000 microg/kg. No significant differences were found between the two extraction solvents, and GC-MS/MS was found to be more specific and sensitive than GC-MS/SIM. The procedures described were shown to be effective in screening, identifying, confirming, and quantitating pesticides in commercial ginseng products. PMID:20225896

  9. Thermodynamics of the amalgam cells {Cs-amalgam|CsX (m)|AgX|Ag} (X=Cl, Br, I) and primary medium effects in (methanol+water) (acetonitrile+water), and (1,4-dioxane+water) solvent mixtures

    The potential difference E of the amalgam cell {CsxHg1-x|CsX (m)|AgX|Ag} (X=Cl, Br, I) has been measured as a function of the mole fraction xCs of Cs metal in amalgams and of the molality m of CsX in (methanol+water) (acetonitrile+water), and (1,4-dioxane+water) solvent mixtures containing up to 0.75 mass fraction of the organic component, at the temperature 298.15K. The respective standard molal potential differences Emo have been determined together with the relevant activity coefficients γ+/- as functions of the CsX molality. The found Emo values show a parabolic decrease with increasing proportion of the organic component in the solvent mixture. Analysis of the relevant primary medium effects upon CsX shows that the CsX transfer from the standard state in water to the standard state in the (aqueous+organic) mixture is always unfavoured, and the acetonitrile is the least unfavoured co-solvent studied. Analysis of the primary medium effect upon CsI in terms of Feakins and French's theory leads to a primary hydration number close to zero, which is consistent with the results of supplementary EXAFS experiments on Cs+ and I- in (acetonitrile+water) solvent mixtures

  10. Acetonitrile­triaqua­[3-eth­oxy-1,8-(3,6,9-trioxaundecane-1,11-diyldi­oxy)-9H-xanthen-9-one]terbium(III) tris­(perchlorate)

    He, Wen-Jie; Pan, Xiao-Bo; Yao, Li-Hui; Yu, Bing-Ran; Wu, Jin-Cai; Tang, Ning

    2010-01-01

    In the title compound, [Tb(CH3CN)(C23H26O8)(H2O)3](ClO4)3, the Tb3+ atom is eight-coordinated by one N atom of an acetonitrile molecule, three water O atoms and four ligand O atoms. The Tb3+ atom is located on one side of the macrocycle and the carbonyl oxygen coordinated to the terbium [Tb1—O1= 2.210 (3) Å] is bent out of the xanthone plane by 0.514 (3) Å. The geometry around terbium is a distorted two-capped trigonal prism.

  11. Aqua(μ-cone-26,28-dibutoxy-25,27-bis{N-[5-(dimethylaminonaphthalene-1-sulfonyl]carbamoylmethoxy}-5,11,17,23-tetrakis(1,1-dimethylethylcalix[4]arene(2−disodium acetonitrile tetrasolvate

    Pogisego Dinake

    2012-04-01

    Full Text Available The structure of the title complex, [Na2(C80H98N4O10S2(H2O]·4CH3CN, obtained after crystallization from acetonitrile, contains two formula units in the asymmetric unit (Z′ = 2 and an estimated four molecules of acetonitrile per calixarene moiety. It is unusual for two Na+ ions to occupy the lower rims of the cone calix[4]arene, as in this case, with one Na+ ion forming two O→ Na+ coordinate bonds with the two butoxy groups and four such bonds with the two N-dansyl carboxamide groups, forming six dative bonds between Na+ and O. On the other hand, the other Na+ ion forms only five O→Na+ coordinate bonds on the far end of the calix[4]arene lower rim, bringing the two dansyl groups in close proximity with each other. There also appears to be an O→Na+ coordination coming from a dangling water molecule. The structure contained both resolved and poorly resolved solvent molecules. The latter were treated using the SQUEEZE routine in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

  12. Cu负载型催化剂用于乙醇氨化合成乙腈%Research on catalysts loaded with Cu for amination of ethanol to acetonitrile

    曹金朋; 胡云峰; 许鹏; 崔宝玉; 董群

    2011-01-01

    研究了不同载体SAPO-11、Montmorillonite-K10、γ-AlO、ZnO和MgO负载Cu的催化剂对乙醇氨化合成乙腈反应的影响.结果表明,经还原的Cu起脱氢作用,载体不仅起分散作用而且具有协同催化的作用,其酸碱性对催化结果有显著影响,其中Cu/γ-AlO负载型催化剂具有比较理想的催化效果.在此研究基础上,考察了反应条件对Cu/γ-AlO催化剂催化性能的影响,筛选出乙醇氨化合成乙腈的适宜反应条件:反应温度290℃、反应压力0.1 MPa、乙醇重时空速1.0 h、氨醇摩尔比7.0,在该条件下乙醇转化率99.7%,乙腈选择性达到92.6%.%The catalytic performance of SAPO-11, montmorillonite-K10, γ-Al2O3, ZnO and MgO loaded with Cu were studied for aminafion of ethanol to acetonitrile. The results showed that reduced copper metal had the function of dehydrogenation, and carriers not only played a role in the dispersion of copper metal but also had a synergistic effect. The acid-base property of carriers was closely related to catalytic results. Among these catalysts, the ideal catalytic results were obtained over the Cu/γ-Al2O3 catalyst. The influence of reaction conditions was investigated, and the favorable conditions of amination of ethanol to acetonitrile over Cu/γ-A12O3 were as follows: reaction temperature of 290℃,reaction pressure of 0.1 MPa, ethanol WHSV of 1.0 h-1 and ammonia/ethanol molar ratio of 7.0. The conversion of ethanol and the selectivity to acetonitrile were 99.7% and 92.6% respectively under the reaction conditions.

  13. Water as a solute in aprotic dipolar solvents. 2. D2O-H2O solute isotope effects on the enthalpy of water dissolution in nitromethane, acetonitrile and propylene carbonate at 298.15 K

    The enthalpies of solution of ordinary (H2O) and heavy (D2O) water in nitromethane (NM), acetonitrile (ACN) and propylene carbonate (PC) were measured calorimetrically at 298.15 K. Standard (at the infinite dilution) enthalpies of solution and solvation, along with D2O-H2O solute isotope effects on the quantities in question, were calculated. The enthalpies of solution of water H/D isotopologues were found to be positive by sign and substantially increasing in magnitude on going from ACN and PC to NM, whereas the corresponding positive solute H/D isotope effect changes in a consequence: NM > ACN > PC. The qualitative interrelations between the enthalpy-isotopic effect of dissolution (solvation) of water and the electron-accepting/donating ability of aprotic dipolar solvent (within a series considered) were found.

  14. Preferential solvation of single ions in mixed solvents: Part 1. New experimental approach and solvation of monovalent ions in methanol-water and acetonitrile-water mixture. Part 2. Theoretical computation and comparison with experimental data

    Preferential solvation of single ion solutions has been studied with Li+, Na+, K+ and Ag+- forms of Dowex 50W resins of different cross-linkings in methanol-water and acetonitrile (AN)- water mixtures. The solvent uptake by this alkali metal ionic forms of Dowex 50W resins was studied in an isopiestic set-up using 2,4,6 and 8 m LiCl solutions in 11.0, 20.8, 44.3 and 70.2 % (w/w) methanol-water mixtures and that of Na+- and Ag+- forms using 14.6 to 94.3 % (w/w) AN - water mixtures. The solvent sorbed in the resin phase was extracted by Rayleigh-type distillation and analysed gas chromatographically. The data were analysed by the Ns (mole fraction of the organic solvent in the resin phase) vs ntau (total solvent content in the resin phase) plots and separation factor, alpha(ratio of mole fraction of the solvents in the resin and solution phases) or Ns vs m (molality in the resin phase) plots. The limiting values of these plots gave the composition of the solvent in the primary solvation shell around the single ion. The compositions of the primary solvation shell around Li+, Na+, and K+ in methanol-water mixtures and Na+ and Ag+in acetonitrile (AN) - water mixtures have been computed using Franks equation and the approach of Marcus and compared with the experimental results obtained with the above mentioned ionic forms of Dowex 50W resins in different mixed solvents. The experimental results for Li+ showed good agreement with the values computed using Franks equation for all methanol-water composition. However, in the case of Na+ and K+ in methanol-water mixtures and Na+ in AN-water mixtures, there was agreement only at lower organic solvent content and the Franks equation predicted higher values for the organic solvent in the primary solvation shell around the cation at higher organic solvent content as compared to experimental results

  15. Crystal structure of tetrakis[μ2-2-(dimethylaminoethanolato-κ3N,O:O]di-μ3-hydroxido-dithiocyanato-κ2N-dichromium(IIIdilead(II dithiocyanate acetonitrile monosolvate

    Julia A. Rusanova

    2016-04-01

    Full Text Available The tetranuclear complex cation of the title compound, [Cr2Pb2(NCS2(OH2(C4H10NO4](SCN2·CH3CN, lies on an inversion centre. The main structural feature of the cation is a distorted seco-norcubane Pb2Cr2O6 cage with a central four-membered Cr2O2 ring. The CrIII ion is coordinated in a distorted octahedron, which involves two N atoms of one bidentate ligand and one thiocyanate anion, two μ2-O atoms of 2-(dimethylaminoethanolate ligands and two μ3-O atoms of hydroxide ions. The coordination geometry of the PbII ion is a distorted disphenoid, which involves one N atom, two μ2-O atoms and one μ3-O atom. In addition, weak Pb...S interactions involving the coordinating and non-coordinating thiocyanate anions are observed. In the crystal, the complex cations are linked through the thiocyanate anions via the Pb...S interactions and O—H...N hydrogen bonds into chains along the c axis. The chains are further linked together via S...S contacts. The contribution of the disordered solvent acetonitrile molecule was removed with the SQUEEZE [Spek (2015. Acta Cryst. C71, 9–18] procedure in PLATON. The solvent is included in the reported molecular formula, weight and density.

  16. High-throughput salting-out assisted liquid-liquid extraction with acetonitrile for the determination of anandamide in plasma of hemodialysis patients with liquid chromatography tandem mass spectrometry.

    Xiong, Xin; Zhang, Lei; Cheng, Litao; Mao, Wei

    2015-09-01

    Anandamide (AEA) is an endocannabinoid present in human plasma that is associated with several physiological functions and disease states. However, low AEA plasma levels pose challenges in terms of analytical characterization. Classical liquid-based lipid extraction and solid-phase extraction require complicated procedures and the drying down of relatively large volumes of solvents, making them unsuitable for high-throughput analysis. Here a high-throughput salting-out assisted liquid-liquid extraction (SALLE) method with acetonitrile and mass spectrometry compatible salts for liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis of AEA in human plasma has been developed and validated. The seamless interface of SALLE and LC-MS eliminated the drying-down step, only 100 μL of plasma is required and minimal volumes of organic solvent are used. Good reproducibility, accuracy and precision were demonstrated during the method validation. The method is linear up to 10 ng/mL with a lower limit of quantitation of 0.1 ng/mL for AEA, the accuracy for AEA was from 93.3 to 96.7% and the precision was <8.57%. This new methodology was successfully applied to analysis of clinical samples from maintenance hemodialysis patients. PMID:25622579

  17. The crystal structures of tetra-kis-(μ-n-butyrato-κ(2) O:O')bis[bromidorhenium(III)] and tetra-kis-(μ-n-butyrato-κ(2) O:O')bis[chlorido-rhenium(III)] aceto-nitrile disolvate.

    Reed, Carly R; Brennessel, William W

    2015-12-01

    The title complexes, [Re2Br2(O2CC3H7)4], (1), and [Re2(O2CC3H7)4Cl2]·2CH3CN, (2), both exhibit paddlewheel structures with four carboxyl-ate ligands bridging two Re(III) atoms. The Re-Re distances are 2.2325 (2) and 2.2299 (3) Å, indicating quadruple bonds between the Re(III) atoms in each complex. Both complexes contain an inversion center at the mid-point of the Re-Re bond. The Re-Br bond [2.6712 (3) Å] in (1) is 0.1656 (6) Å longer than the Re-Cl distance [2.5056 (5) Å] of (2). In (2), the N atom of each co-crystallized aceto-nitrile solvent mol-ecule is nearly equidistant between and in close contact with two carboxyl-ate C atoms. PMID:26870409

  18. Bi-anchoring organic sensitizers of type D-(π-A)2 comprising thiophene-2-acetonitrile as π-spacer and malonic acid as electron acceptor for dye sensitized solar cell applications

    Reddy, Gachumale Saritha; Ramkumar, Sekar; Asiri, Abdullah M.; Anandan, Sambandam

    2015-06-01

    Two new bi-anchoring organic sensitizers of type D-(π-A)2 comprising the identical π-spacer (thiophene-2-acetonitrile) and electron acceptor (malonic acid) but different aryl amine as electron donors (diphenylamine and carbazole) were synthesized, characterized and fabricated metal free dye-sensitized solar cell devices. The intra molecular charge transfer property and electrochemical property of these dyes were investigated by molecular absorption, emission, cyclic voltammetric experiments and in addition, quantum chemical calculation studies were performed to provide sufficient driving force for the electron injection into the conduction band of TiO2 which leads to efficient charge collection. Among the fabricated devices, carbazole based device exhibits high current conversion efficiency (η = 4.7%) with a short circuit current density (JSC) 15.3 mA/cm2, an open circuit photo voltage (VOC) of 0.59 V and a fill factor of 0.44 under AM 1.5 illumination (85 mW/cm2) compared to diphenylamine based device.

  19. Bi-anchoring organic sensitizers of type D-(π-A)₂ comprising thiophene-2-acetonitrile as π-spacer and malonic acid as electron acceptor for dye sensitized solar cell applications.

    Reddy, Gachumale Saritha; Ramkumar, Sekar; Asiri, Abdullah M; Anandan, Sambandam

    2015-06-15

    Two new bi-anchoring organic sensitizers of type D-(π-A)2 comprising the identical π-spacer (thiophene-2-acetonitrile) and electron acceptor (malonic acid) but different aryl amine as electron donors (diphenylamine and carbazole) were synthesized, characterized and fabricated metal free dye-sensitized solar cell devices. The intra molecular charge transfer property and electrochemical property of these dyes were investigated by molecular absorption, emission, cyclic voltammetric experiments and in addition, quantum chemical calculation studies were performed to provide sufficient driving force for the electron injection into the conduction band of TiO2 which leads to efficient charge collection. Among the fabricated devices, carbazole based device exhibits high current conversion efficiency (η=4.7%) with a short circuit current density (JSC) 15.3 mA/cm(2), an open circuit photo voltage (VOC) of 0.59 V and a fill factor of 0.44 under AM 1.5 illumination (85 mW/cm(2)) compared to diphenylamine based device. PMID:25801442

  20. Electrochemistry of Flavonolignans in Acetonitrile and Dimethylsulfoxide

    Sokolová, Romana; Kocábová, Jana; Fiedler, Jan; Vacek, J.; Marhol, Petr; Vavříková, Eva; Křen, Vladimír

    Ústí nad Labem : Best Servis, 2014 - (Navrátil, T.; Fojta, M.; Pecková, K.), s. 161-165 ISBN 978-80-905221-2-1. [Moderní Elektrochemické Metody /34./. Jetřichovice (CZ), 19.05.2014-23.05.2014] R&D Projects: GA ČR(CZ) GAP207/11/0629 Grant ostatní: Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR M200401201 Institutional support: RVO:61388955 ; RVO:61388971 Keywords : Silybin * 2,3-Dehydrosilybin * Electron transfer Subject RIV: CG - Electrochemistry ; CE - Biochemistry (MBU-M)

  1. Crystal structure of (2,11-diaza[3.3](2,6pyridinophane-κ4N,N′,N′′,N′′′(1,6,7,12-tetraazaperylene-κ2N1,N12ruthenium(II bis(hexafluoridophosphate acetonitrile 1.422-solvate

    Thomas Brietzke

    2014-10-01

    Full Text Available In the title compound, [Ru(C14H16N4(C16H8N4](PF62·1.422CH3CN, discrete dimers of complex cations, [Ru(L–N4H2tape]2+ are formed {L–N4H2 = 2,11-diaza[3.3](2,6pyridinophane; tape = 1,6,7,12-tetraazaperylene}, held together by π–π stacking interactions via the tape ligand moieties with a centroid–centroid distance of 3.49 (2 Å, assisted by hydrogen bonds between the non-coordinating tape ligand α,α′-diimine unit and the amine proton of a 2,11-diaza[3.3](2,6-pyridinophane ligand of the opposite complex cation. The combination of these interactions leads to an unusual nearly face-to-face π–π stacking mode. Additional weak C—H...N, C—H...F, N—H...F and P—F...π-ring (tape, py (with F...centroid distances of 2.925–3.984 Å interactions are found, leading to a three-dimensional architecture. The RuII atom is coordinated in a distorted octahedral geometry, particularly manifested by the Namine—Ru—Namine angle of 153.79 (10°. The counter-charge is provided by two hexafluoridophosphate anions and the asymmetric unit is completed by acetonitrile solvent molecules of crystallization. Disorder was observed for both the hexafluoridophosphate anions as well as the acetonitrile solvate molecules, with occupancies for the major moieties of 0.801 (6 for one of the PF6 anions, and a shared occupancy of 0.9215 (17 for the second PF6 anion and a partially occupied acetonitrile molecule. A second CH3CN molecule is fully occupied, but 1:1 disordered across a crystallographic inversion center.

  2. (1,6,7,12-Tetraazaperylene-κ2N,N′bis(4,4′,5,5′-tetramethyl-2,2′-bipyridyl-κ2N,N′ruthenium(II bis(hexafluoridophosphate acetonitrile trisolvate

    Thomas Brietzke

    2014-06-01

    Full Text Available In the title compound, rac-[Ru(C14H16N22(C16H8N4](PF62·3C2H3N, discrete dimers of complex cations, [Ru(tmbpy2tape]2+, of opposite chirality are formed (tmbpy = tetramethylbipyridine; tape = tetraazaperylene, held together by π–π stacking interactions between the tetraazaperylene moieties with centroid–centroid distances in the range 3.563 (3–3.837 (3 Å. These interactions exhibit a parallel displaced π–π stacking mode. Additional weak C—H...π-ring and C—H...N and C—H...F interactions are found, leading to a three-dimensional architecture. The RuII atom is coordinated in a distorted octahedral geometry. The counter-charge is provided by two hexafluoridophosphate anions and the asymmetric unit is completed by three acetonitrile solvent molecules of crystallization. Four F atoms of one PF6− anion are disordered over three sets of sites with occupancies of 0.517 (3:0.244 (3:0.239 (3. Two acetonitrile solvent molecules are highly disordered and their estimated scattering contribution was subtracted from the observed diffraction data using the SQUEEZE option in PLATON [Spek (2009. Acta Cryst. D65, 148–155].

  3. 2-[2-(4,6-二甲氧基嘧啶-2-氧)苯基]-2-(取代苯胺)乙氰类化合物的合成及除草活性研究%Synthesis and Herbicidal Activities of 2-[2-(4,6-Dimethoxypyrimidin-2- yloxy)phenyl]-2-(substituted aniline)acetonitrile Derivatives

    李元祥; 刘玉超; 陈琼

    2011-01-01

    Using 2-hydroxybenzaldehyde as starting material, twelve 2-[2-(4,6-dimethoxypyrimidin-2-yloxy)phenyl]-2-(substituted aniline)acetonitrile derivatives have been synthesized by one-pot three-component reaction of 2-(4,6-dimethoxypyrimidin-2-yloxy)benzaldehyde intermediate. All synthesized compounds were confirmed by 1H NMR, MS techniques and elemental analysis. High herbicidal activities of all compounds were showed at preliminary bioassay.%以水杨醛为原料,所得中间体2-(4,6-二甲氧基嘧啶-2-氧基)苯甲醛经三组分反应合成了12个2-[2-(4,6-二甲氧基嘧啶-2-氧基)苯基]-2-(取代苯胺)乙氰类化合物,通过1H NMR,MS和元素分析对所合成的化合物进行了结构表征.初步生物活性测试结果表明,在试验浓度下合成化合物均具有良好的除草活性.

  4. Ionization and dissociation of acetonitrile by intense femtosecond laser pulse

    2000-01-01

    Photoionization and photodissociation of CH3CN were studied by a linear time of flight mass spectrometer coupled with 800 nm, 50 fs laser pulses at intensities of 6.3×1013-1.2×1014 W/cm2. The laser power dependences for principal ions CH3CN+, CH2CN+, CHCN+ and CCN+ were measured, which are consistent with the numbers of photons required to produce the ions via multiphoton ionization and dissociation. The results show that eight-photon non-resonant multiphoton ionization is the main photoionization mechanism of the parent ion CH3CN+, while the fragment ions were produced through the dissociation of the molecules in the super-excited states.

  5. Bromidotris(triphenyl­phosphane)silver acetonitrile monosolvate monohydrate

    Owczarzak, Anita M.; Loukas Kyros; Sotiris K. Hadjikakou; Maciej Kubicki

    2011-01-01

    In the title compound, [AgBr(C18H15P)3]·C2H3N·H2O, the coordination of the Ag atom is close to ideal tetrahedral, with the three Ag—P bond lengths almost equal [2.5441 (10), 2.5523 (9) and 2.5647 (10) ° A] and the Ag—Br bond slightly longer [2.7242 (5) Å]. The coordination tetrahedron is slightly flattened, the Ag atom is closer to the PPP plane; the P—Ag—P angles are ...

  6. Reduction and Oxidation of Hydroxyquinolines in Acetonitrile and Dimethylsulfoxide

    Sokolová, Romana; Ramešová, Šárka; Fiedler, Jan; Kolivoška, Viliam; Degano, I.; Gál, M.; Szala, M.; Nycz, J. E.

    Ústí nad Labem : Srsenová Lenka - Best Servis, 2015 - (Navrátil, T.; Fojta, M.; Schwarzová, K.), s. 204-208 ISBN 978-80-905221-3-8. [Moderní elektrochemické metody /35./. Jetřichovice (CZ), 18.05.2015-22.05.2015] Grant ostatní: Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR M200401201 Institutional support: RVO:61388955 Keywords : quinolines * hydroxyquiolines * reduction Subject RIV: CG - Electrochemistry

  7. 一种水溶性氢氧根钌配合物的合成及其对乙腈的催化水化作用%Synthesis of a Water-Soluble Ruthenium Hydroxide Complex and Its Role in Catalytic Hydration of Acetonitrile

    尹传奇; 刘珺; 柏正武

    2011-01-01

    以RuCl3·3H2O为原料合成了水溶性钌配合物[(bipy)2Ru(H2O)2](OTf)2(bipy=2,2'-bipyridine,Otf-=triflate),利用DBU(1,8-Diazabicyclo[5.4.0]undec-7-ene)脱质子化合成了水溶性氢氧根配合物[(bipy)2Ru(H2O)(OH)](OTf).研究了[(bipy)2Ru(H2O)(OH)](OTf)催化水化乙腈生成乙酰胺的反应.机理研究表明,催化循环的关键中间体为氧配位的酰亚胺配合物[(bipy)2Ru(CH3CN)(OCMe=NH)]+,经过生成[(bipy)2Ru(κ2-N,O-NH=CMeN=CMeO)]+、水亲核进攻开环生成{(bipy)2Ru[NH=C(OH)Me](OCMe=NH)}+、乙腈取代其NH=C(OH)Me配体产生乙酰胺,同时再生成[(bipy)2Ru-(CH3CN)(OCMe=NH)]+完成催化循环.%In the presence of DBU(1,8-Diazabicycloundec-7-ene),a novel water-soluble hydroxide ruthenium complex [(bipy)2Ru(H2O)(OH)](OTf) was synthesized by deprotonation of [(bipy)2Ru(H2O)2]-(OTf)2(bipy=2,2'-bipyridine,Otf-=triflate),which was prepared using RuCl3·3H2O as starting material.The hydration of acetonitrile to form acetamide catalyzed by [(bipy)2Ru(H2O)(OH)](OTf) was studied.O-bonded imido complex [(bipy)2Ru(N≡CCH3)(OCMe=NH)]+ is postulated to be the key intermediate,which then undergoes nucleophilic attack at the carbon atom of nitrile ligand to form [(bipy)2Ru(k2-N,ONH=CMeN=CMeO)]+.Ring-opening nucleophilic attack of [(bipy)2Ru(k2-N,O-NH=CMeN=CMeO)]+by water produces {(bipy)2Ru[NH=C(OH)Me](OCMe=NH)}+.The displacement of NH=C(OH)Me ligand in the latter complex by acetonitrile forms acetamide,and regenerates [(bipy)2Ru(N≡CCH3)-(OCMe=NH)]+ to fulfill catalytic cycle.

  8. Crystal structure of tetra-kis-[μ2-2-(di-methyl-amino)-ethano-lato-κ(3) N,O:O]di-μ3-hydroxido-di-thio-cyanato-κ(2) N-dichromium(III)dilead(II) di-thio-cyanate aceto-nitrile monosolvate.

    Rusanova, Julia A; Semenaka, Valentyna V; Omelchenko, Irina V

    2016-04-01

    The tetra-nuclear complex cation of the title compound, [Cr2Pb2(NCS)2(OH)2(C4H10NO)4](SCN)2·CH3CN, lies on an inversion centre. The main structural feature of the cation is a distorted seco-norcubane Pb2Cr2O6 cage with a central four-membered Cr2O2 ring. The Cr(III) ion is coordinated in a distorted octa-hedron, which involves two N atoms of one bidentate ligand and one thio-cyanate anion, two μ2-O atoms of 2-(di-methyl-amino)-ethano-late ligands and two μ3-O atoms of hydroxide ions. The coordination geometry of the Pb(II) ion is a distorted disphenoid, which involves one N atom, two μ2-O atoms and one μ3-O atom. In addition, weak Pb⋯S inter-actions involving the coordinating and non-coordinating thio-cyanate anions are observed. In the crystal, the complex cations are linked through the thio-cyanate anions via the Pb⋯S inter-actions and O-H⋯N hydrogen bonds into chains along the c axis. The chains are further linked together via S⋯S contacts. The contribution of the disordered solvent aceto-nitrile mol-ecule was removed with the SQUEEZE [Spek (2015 ▸). Acta Cryst. C71, 9-18] procedure in PLATON. The solvent is included in the reported mol-ecular formula, weight and density. PMID:27375871

  9. An acetonitrile solvatomorph of dichlorido(1,10-phenanthroline-5,6-dioneplatinum(II

    Amanda Hamala

    2014-01-01

    Full Text Available In the title complex, [PtCl2(C12H6N2O2]·CH3CN, the PtII atom lies in a slightly distorted square-planar arrangement defined by an N2Cl2 donor set. In the packed structure, columns of complex moieties are stacked such that the neighboring units are oriented at 180° and laterally displaced with respect to each other. This prevents any overlap of the phenanthroline rings and thus there is no possibility of any π–π interactions between aromatic rings.

  10. A conductivity study of preferential solvation of lithium ion in acetonitrile-dimethyl sulfoxide mixtures

    The electrical mobility of LiPF6 in acetonitrile–dimethyl sulfoxide (ACN–DMSO) mixtures, a potential electrolyte in oxygen cathodes of lithium-air batteries, has been studied using a very precise conductance technique, which allowed the determination of the infinite dilution molar conductivity and association constant of the salt in the whole composition range. In the search for preferential Li+ ion solvation, we also measured the electrical conductivity of tetrabutylammonium hexafluorophosphate (TBAPF6), a salt formed by a bulky cation, over the same composition range. The results show a qualitative change in the curvature of the LiPF6 molar conductivity composition dependence for ACN molar fraction (xACN) ∼ 0.95, which was not observed for TBAPF6. The dependence of the measured Li/Li+ couple potential with solvent composition also showed a pronounced change around the same composition. We suggest that these observations can be explained by Li+ ion preferential solvation by DMSO in ACN–DMSO mixtures with very low molar fractions of DMSO

  11. SbCl5—wet acetonitrile: a new system for chemoselective O-desilylation

    Glória, Paulo M. C.; Prabhakar, Sundaresan; Lobo, Ana M; Gomes, Mário

    2003-01-01

    Abstract—A new efficient method for deprotection of TBDMS derivatives of phenols, primary alcohols, carboxylic acids and secondary amines, consisting of SbCl5 and MeCN with 0.1% water (w/v), is reported. It effects inter alia desilylation of a CH2OTBDMS group in the presence of a ketal function.

  12. The effect of deuterium substitution on the vapor pressure of acetonitrile

    The vapor pressure difference between CH3CN and CD3CN was measured by differential capacitance manometry between -40 and +80 deg C. The vapor pressure isotope effects (VPIE) derived from the results may be expressed by the equation: ln(psub(H)/Psub(D))=871.761/T2-13.577/T+0.006874. The experimental data were interpreted within the framework of the statistical theory of isotope effects in condensed systems. The largest contribution to the VPIE arises from the shifts in the CH stretching vibrations resulting from condensation which were found to be temperature dependent in good agreement with the available spectroscopic information. (author)

  13. An alternative pathway for production of acetonitrile: ruthenium catalysed aerobic dehydrogenation of ethylamine

    Corker, Emily; Mentzel, Uffe Vie; Mielby, Jerrik Jørgen;

    2013-01-01

    conditions, achieving over 90% selectivity in the batch process and 80% selectivity in the continuous flow process. The use of a selective solid catalyst that utilises a feedstock that can be derived from biomass, dioxygen as the oxidant and water as the solvent represents a new, green route for the...

  14. Radiation chemistry of aqueous solutions of acetonitrile and propionitrile in the megarad dose range

    A study was made of the radiolytic behavior of dilute, neutral, oxygen-free aqueous solutions of CH3CN and C2H5CN. Small-molecular products were identified as RCHO, NH3, CO2, and H2. The decomposition of nitrile is followed by high yields of formation of the nonvolatile nitrogen-containing compounds, G(N). The γ-irradiated solutions exhibit a positive biuret reaction. Several amino acids were identified among radiolytic products, and glycine and alanine were found to be the most abundant for CH3CN and C2H5CH, respectively. Their yields increased after strong acid hydrolysis of the irradiated samples. The free radicals formed by reactions of RCN with H, OH, and e/sub aq/- were found to be important for the phenomena observed. It is suggested that the positive biuret reaction, ir spectra, and the release of amino acids on acid hydrolysis provide some evidence on the formation of peptidic materials and might be of interest for the evaluation of the role that ionizing radiation might have played in prebiotic chemical evolution in aqueous media

  15. Radiation chemistry of aqueous solutions of acetonitrile and propionitrile in the megarad dose range. [. gamma. Radiation

    Draganic, Z.D.; Draganic, I.G.; Shushtarian, M.J.

    1976-04-01

    A study was made of the radiolytic behavior of dilute, neutral, oxygen-free aqueous solutions of CH/sub 3/CN and C/sub 2/H/sub 5/CN. Small-molecular products were identified as RCHO, NH/sub 3/, CO/sub 2/, and H/sub 2/. The decomposition of nitrile is followed by high yields of formation of the nonvolatile nitrogen-containing compounds, G(N). The ..gamma..-irradiated solutions exhibit a positive biuret reaction. Several amino acids were identified among radiolytic products, and glycine and alanine were found to be the most abundant for CH/sub 3/CN and C/sub 2/H/sub 5/CH, respectively. Their yields increased after strong acid hydrolysis of the irradiated samples. The free radicals formed by reactions of RCN with H, OH, and e/sub aq/- were found to be important for the phenomena observed. It is suggested that the positive biuret reaction, ir spectra, and the release of amino acids on acid hydrolysis provide some evidence on the formation of peptidic materials and might be of interest for the evaluation of the role that ionizing radiation might have played in prebiotic chemical evolution in aqueous media.

  16. Determination of Pesticide Residues in Foods by Acetonitrile Extraction and Partitioning with Magnesium Sulfate: Collaborative Study

    A collaborative study was conducted to determine multiple pesticide residues in fruits and vegetables using a quick, simple, inexpensive, and effective sample preparation method followed by concurrent analysis with gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-tandem mass sp...

  17. Localization of Double Bonds in Fatty Acids Utilizing Acetonitrile-Related Adducts Generated in the APCI Source

    Vrkoslav, Vladimír; Hoskovec, Michal; Cvačka, Josef

    Elsevier. Roč. 22, Suppl. 1 (2011), MP245-MP245. ISSN 1044-0305. [ASMS Conference on Mass Spectrometry and Allied Topics. 05.06.2011-09.06.2011, Denver] R&D Projects: GA ČR GA203/09/0139 Institutional research plan: CEZ:AV0Z40550506 Keywords : fatty acids * lipids * HPLC/APCI-MS/MS * GC/MS Subject RIV: CC - Organic Chemistry

  18. Kinetic Study on Aminolysis of 4-Nitrophenyl Isonicotinate in Acetonitrile: Effect of Amine Basicity on Reactivity and Reaction Mechanism

    A kinetic study is reported on nucleophilic substitution reactions of 4-nitrophenyl isonicotinate with a series of cyclic secondary amines in MeCN. The plots of kobsd vs. [amine] curve upward for the reactions with weakly basic amines (e. g., morpholine, 1-(2-hydroxyethyl)piperazine, and piperazine) but are linear for those with strongly basic amines (e. g., piperidine and 3-methylpiperidine). The curved plots for the reactions with the weakly basic amines are typical for reactions reported previously to proceed through uncatalyzed and catalyzed routes with two intermediates (e. g., a zwitterionic tetrahedral intermediate T± and its deprotonated form T-). In contrast, the linear plots for the reactions with the strongly basic amines indicate that the catalytic route (i. e., the deprotonation process to yield T- from T± by a second amine molecule) is absent. The Brφnsted-type plots for Kk2 and Kk3 (i. e., the rate constants for the uncatalyzed and catalyzed routes, respectively) exhibit excellent linear correlations with βnuc = 0.99 and 0.69, respectively. The effect of amine basicity on the reaction mechanism is discussed in detail

  19. Effect of Growth Temperature on Bamboo-shaped Carbon–Nitrogen (C–N Nanotubes Synthesized Using Ferrocene Acetonitrile Precursor

    Dobal PramodSingh

    2008-01-01

    Full Text Available Abstract This investigation deals with the effect of growth temperature on the microstructure, nitrogen content, and crystallinity of C–N nanotubes. The X-ray photoelectron spectroscopic (XPS study reveals that the atomic percentage of nitrogen content in nanotubes decreases with an increase in growth temperature. Transmission electron microscopic investigations indicate that the bamboo compartment distance increases with an increase in growth temperature. The diameter of the nanotubes also increases with increasing growth temperature. Raman modes sharpen while the normalized intensity of the defect mode decreases almost linearly with increasing growth temperature. These changes are attributed to the reduction of defect concentration due to an increase in crystal planar domain sizes in graphite sheets with increasing temperature. Both XPS and Raman spectral observations indicate that the C–N nanotubes grown at lower temperatures possess higher degree of disorder and higher N incorporation.

  20. Double bond localization in wax ester molecular species by HPLC/APCI-MS utilizing CID of the acetonitrile adducts

    Vrkoslav, Vladimír; Háková, M.; Cvačka, Josef

    Salt Lake City, Utah, 2010. -. [ASMS Conference on Mass Spectrometry and Allied Topics /58./. 23.05.-27.05.2010, Salt Lake City, Utah] R&D Projects: GA ČR GA203/09/0139 Institutional research plan: CEZ:AV0Z40550506 Keywords : wax esters * APCI * double bond

  1. 2-{4-[(2,2-Dimethyl-4,6-dioxo-1,3-dioxan-5-ylidenemethylamino]phenyl}acetonitrile

    Rui Li

    2009-06-01

    Full Text Available The title compound, C15H14N2O4, is approximately planar, with a dihedral angle of 6.48 (4° between the aminomethylene unit and the planar five-atom part of the dioxane ring, and a dihedral angle of 2.40 (4° between aminomethylene unit and the phenylene ring. The dioxane ring is envelope shaped, with the dimethyl-substituted C atom that represents the flap 0.535 (8 Å out of the plane. The molecule has an intramolecular N—H...O hydrogen bond.

  2. 8-Hydroxy-2-methylquinolinium tetrachlorido(quinolin-8-olato-κ2N,O)stannate(IV) acetonitrile monosolvate

    Marzieh Vafaee; Gholamhossein Mohammadnezhad; Amini, Mostafa M.; Seik Weng Ng

    2010-01-01

    In the title solvated salt, (C10H10NO)[SnCl4(C9H6NO)]·CH3CN, the SnIV atom is chelated by the N,O-bidentate 8-hydroxyquinolinate ligand and four chloride ions, generating a distorted SnONCl4 octahedral coordination geometry for the metal. In the crystal, the cations are linked to the anions and the solvent molecules by O—H...O and N—H...N hydrogen bonds, respectively.

  3. 8-Hydroxy-2-methylquinolinium tetrachlorido(quinolin-8-olato-κ2N,Ostannate(IV acetonitrile monosolvate

    Marzieh Vafaee

    2010-04-01

    Full Text Available In the title solvated salt, (C10H10NO[SnCl4(C9H6NO]·CH3CN, the SnIV atom is chelated by the N,O-bidentate 8-hydroxyquinolinate ligand and four chloride ions, generating a distorted SnONCl4 octahedral coordination geometry for the metal. In the crystal, the cations are linked to the anions and the solvent molecules by O—H...O and N—H...N hydrogen bonds, respectively.

  4. Stereoisomeric products of electrochemical reduction of heterocyclic Fischer aminocarbene Cr(0) complexes. Development of the electrochemistry-mass spectrometry tandem approach using biphasic (acetonitrile-hexane) preparative electrolysis

    Metelková, R.; Hoskovcová, I.; Polášek, Miroslav; Urban, Jiří; David, T.; Ludvík, Jiří

    2015-01-01

    Roč. 162, APR 2015 (2015), s. 17-23. ISSN 0013-4686 R&D Projects: GA ČR GAP206/11/0727 Institutional support: RVO:61388955 Keywords : Fischer aminocarbene complexes biphasic electrolysis * EC-MS * HPLC-NMR Subject RIV: CG - Electrochemistry Impact factor: 4.504, year: 2014

  5. Bis[μ-1-(3,5-dichloropyridin-2-yl-2-(pyridin-3-ylmethylidenehydrazine]bis[(nitrato-κOsilver(I] acetonitrile disolvate

    Ying Guo

    2013-10-01

    Full Text Available In the centrosymmetric binuclear title complex, [Ag2(NO32(C11H8Cl2N42]·2CH3CN, the AgI atom is four-coordinated and exhibits a highly distorted tetrahedral coordination sphere defined by three N atoms from two 1-(3,5-dichloropyridin-2-yl-2-(pyridin-3-ylmethylidenehydrazine ligands and one O atom from a nitrate anion. Intermolecular N—H...O hydrogen bonds link the complex molecules, resulting in a two-dimensional supramolecular structure parallel to (001.

  6. Probing the Early Stages of Solvation of cis-Pinate Dianions by Water, Acetonitrile, and Methanol: A Photoelectron Spectroscopy and Theoretical Study

    Hou, Gao-Lei; Kong, Xiang-Tao; Valiev, Marat; Jiang, Ling; Wang, Xue B.

    2016-01-01

    Cis-pinic acid is one of the most important oxidation products of α-pinene – a key monoterpene compound in biogenic emission processes affecting the atmosphere. Molecular level understanding of interactions involved in the cluster formations around cis-pinic acid is an important and necessary prerequisite toward ascertaining its role in the aerosol formation processes. In this work, we studied the structures and energetics of the solvated clusters of cis-pinate (cis-PA²⁻), the doubly deprotonated dicarboxylate of cis-pinic acid, with H₂O, CH₃OH, and CH₃CN by negative ion photoelectron spectroscopy and ab initio theoretical calculations. We found that cis-PA²⁻ prefers being solvated alternately on the two -CO₂⁻ groups with increase of solvent coverage, a well-known solvation pattern that has been observed in microhydrated linear dicarboxylate dianion (DCn²⁻) clusters. Experiments and calculations further reveal an intriguing feature for the existence of the asymmetric type isomers for cis-PA2–(H2O)2 and cis-PA²⁻(CH₃OH)₂, in which both solvent molecules interact with only one of the -CO²⁻ groups – a phenomena that has not been observed in DCn²⁻ water clusters and exhibits the subtle effect of the rigid four-membered carbon ring brought in on the cis-PA²⁻ solvation. The dominant interactions between cis-PA²⁻ and solvent molecules are forming bidentate O–···H–O H-bonds for H₂O, O–···H–O and O–···H–C H-bonds for CH₃OH, and tridentate O–···H–C H-bonds for CH₃CN. The formation of inter-solvent H-bonds between H₂O and CH₃CN is found to be favorable in mixed solvent clusters, distinctly different from that between H₂O and CH₃OH. These findings have important implications for understanding the mechanism of cluster growth and nucleation of atmospheric organic aerosols and the nature of structure-function relationship of proteins containing carboxylate groups under various solvent environments.

  7. 生物乙醇催化氨化法制备乙腈工艺研究%Study on Acetonitrile Synthesis from Bioethanol by Catalytic Ammoniation Method

    支世涛; 李华锋

    2015-01-01

    采用自制的高活性混合金属催化剂,对生物乙醇氮化合成乙二胺工艺进行研究.利用气相色谱内标法对产品进行定量分析,通过单因素和正交设计实验确定了乙二胺合成的最佳条件:温度:260℃,氨醇比:2,空速:0.2h-1,压力为常压.

  8. Effect of the Range of Interactions on the Properties of Fluids. 2. Structure and Phase Behavior of Acetonitrile, Hydrogen Fluoride, and Formic Acid

    Chialvo, A.A.; Kettler, M.; Nezbeda, Ivo

    2005-01-01

    Roč. 109, č. 19 (2005), s. 9736-9750. ISSN 1520-6106 R&D Projects: GA AV ČR IAA4072303 Grant ostatní: OBES(US) DE/AC05/00OR22725 Institutional research plan: CEZ:AV0Z40720504 Keywords : coulombic interactions * phase behaviour * perturbation theory Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 4.033, year: 2005

  9. Effect of the Range of Interactions on the Properties of Fluids. 2. Structure and Phase Behavior of Acetonitrile, Hydrogen Fluoride, and Formic Acid

    Chialvo, A.A.; Kettler, M.; Nezbeda, Ivo

    2005-01-01

    Roč. 109, - (2005) , s. 9736-9750. ISSN 1089-5647 R&D Projects: GA AV ČR IAA4072303 Grant ostatní: OBES(US) DE/AC05/00OR22725 Institutional research plan: CEZ:AV0Z40720504 Keywords : coulombic interactions * phase behaviour * perturbation theory Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.679, year: 2003

  10. Vitamin D analysis in plasma by high performance liquid chromatography (HPLC) with C30 reversed phase column and UV detection - easy and acetonitrile-free

    Hymøller, Lone; Jensen, Søren Krogh

    2011-01-01

    of animals and humans. Therefore cheap and reliable analytical methods are very much in demand in nutritional and physiological research. After saponification and extraction of plasma or serum samples the current method uses reverse phase high performance liquid chromatography on a C30 column and...

  11. 乙醇与氨脱氢法合成乙腈%The Method to Manufacture Acetonitrile by Dehydrogenation from Ethanol and Ammonia

    张海松

    2009-01-01

    介绍了乙腈的制造方法和国内主要厂家的产能情况及工业开发情况;重点介绍了乙醇与氨脱氢法合成乙腈的工艺过程、催化剂选择,并进行简单的经济性分析.

  12. Rate constants and temperature effects for reactions of Cl2sm-bullet- with unsaturated alcohols and hydrocarbons in aqueous and acetonitrile/water solutions

    Absolute rate constants for reactions of the dichlorine radical anion, Cl2sm-bullet-, with unsaturated alcohols and hydrocarbons have been measured at various temperatures. The alcohol reactions were measured in aqueous solutions and the hydrocarbon reactions in 1:1 aqueous acetonitirle (ACN) solutions. The rate constants for two alcohols and one hydrocarbon were also examined as a function of solvent composition. The room temperature rate constants varied between 106 and 109 M-1 s-1. The pre-exponential factors, A, were about (1-5) x 109 M-1 s-1 for the alcohols in aqueous solutions and about (0.1-1) x 109 M-1 s-1 for the hydrocarbons in aqueous ACN solutions. The activation energies, Ea, varied considerably, between 4 and 12 kJ mol-1 for the alcohols and between 2 and 8 kJ mol-1 for the hydrocarbons. The rate constants, k298, decrease with increasing ionization potential (IP) of the unsaturated compound, in agreement with an electrophilic addition mechanism. The activation energies for the unsaturated alcohols decrease when the IP decreases from 9.7 to 9.1 eV but appear to level off at lower IP. Most alkenes studied had IP a. Upon addition of ACN to the aqueous solution, the values of log k298 decreased linearly by more than 1 order of magnitude with increasing ACN mole fraction. This decrease appears to result from a combination of changes in the activation energy and in the pre-exponential factor. The reason for these changes may lie in changes in the solvation shell of the Cl2sm-bullet- radical, which will affect the A factor, in combination with changes in solvation of Cl-, which will affect the energetics of the reactions as well. 20 refs., 7 figs., 6 tabs

  13. 5,11,17,23,29,35-Hexa-tert -butyl-37,38,39,40,41,42-hexakis-(ethoxycarbonylmethoxy)calix[6]arene acetonitrile disolvate

    Pojarová, Michaela; Dušek, Michal; Budka, J.; Císařová, I.; Makrlík, E.

    2012-01-01

    Roč. 68, č. 5 (2012), "o1418"-"sup13". ISSN 1600-5368 Grant ostatní: AV ČR(CZ) Praemium Academiae Institutional research plan: CEZ:AV0Z10100521 Keywords : calix[6]arene * SHELX * crystal structure Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.347, year: 2011

  14. 8-Hydr­oxy-2-methyl­quinolinium tetra­chlorido(quinolin-8-olato-κ2 N,O)stannate(IV) acetonitrile monosolvate

    Vafaee, Marzieh; Mohammadnezhad, Gholamhossein; Amini, Mostafa M.; Ng, Seik Weng

    2010-01-01

    In the title solvated salt, (C10H10NO)[SnCl4(C9H6NO)]·CH3CN, the SnIV atom is chelated by the N,O-bidentate 8-hydroxy­quinolinate ligand and four chloride ions, generating a distorted SnONCl4 octa­hedral coordination geometry for the metal. In the crystal, the cations are linked to the anions and the solvent mol­ecules by O—H⋯O and N—H⋯N hydrogen bonds, respectively.

  15. Localization of Double Bonds in Wax Esters by High-Performance Liquid Chromatography/Atmospheric Pressure Chemical Ionization Mass Spectrometry Utilizing Fragmentation of Acetonitrile-Related Adducts

    Vrkoslav, Vladimír; Háková, Martina; Pecková, K.; Urbanová, Klára; Cvačka, Josef

    2011-01-01

    Roč. 83, č. 8 (2011), s. 2978-2986. ISSN 0003-2700 R&D Projects: GA ČR GA203/09/0139 Institutional research plan: CEZ:AV0Z40550506 Keywords : Ion-molecule reactions * lipids Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 5.856, year: 2011

  16. Kinetic Study on Nucleophilic Displacement Reactions of Y-Substituted-Phenyl 2-Methylbenzoates with Cyclic Secondary Amines in Acetonitrile: Effects of Modification of 2-MeO in Benzoyl Moiety by 2-Me on Reactivity and Reaction Mechanism

    The second-order rate constants (kN) have been measured spectrophotometrically for nucleophilic substitution reactions of Y-substituted-phenyl 2-methylbenzoates (6a-e) with a series of cyclic secondary amines in MeCN at 25.0 ± 0.1 .deg. C. Comparison of the kN values for the reactions of 4-nitrophenyl 2-methylbenzoate (6d) with those reported previously for the corresponding reactions of 4-nitrophenyl 2-methoxybenzoate (5) reveals that 6d is significantly less reactive than 5, indicating that modification of 2-MeO in the benzoyl moiety of 5 by 2-Me (i. e., 5 → 6d) causes a significant decrease in reactivity. This supports our previous report that aminolysis of 5 proceeds through a six-membered cyclic intermediate, which is highly stabilized through intramolecular H-bonding interactions. The Brφnsted-type plot for the reactions of 6d with a series of cyclic secondary amines is linear with βnuc = 0.71, which appears to be a lower limit of βnuc for a stepwise mechanism with breakdown of an intermediate (T±) being rate-determining step (RDS). The Brφnsted-type plot for the reactions of 6a-e with piperidine is curved, i. e., the slope of Brφnsted-type plot (βlg) decreases from -1.05 to -0.41 as the leaving-group basicity decreases. The nonlinear Brφnsted-type plot has been taken as evidence for a stepwise mechanism with a change in RDS (e. g., from the k2 step to the k1 process as the leaving-group basicity decreases). Dissection of kN into the microscopic rate constants associated with the reactions of 6a-e with piperidine (e. g., k1 and k2/k-1 ratio) also supports the proposed mechanism

  17. Crystal structure of tris-(μ-bis-{4-[(pyridin-2-yl-methyl-idene)amino]-phen-yl}methane-κ(4) N,N':N'',N''')dizinc tetra-kis-(tetra-fluorido-borate) aceto-nitrile tris-olvate.

    Alexandru, Maria-Gabriela; Dumitru, Florina

    2015-12-01

    The asymmetric unit of the title compound, [Zn2(C25H20N4)3](BF4)4·3CH3CN, consists of one dinuclear Zn(II) complex cation with a triple-helical [Zn2 L 3](4+) motif (L is bis-{4-[(pyridin-2-yl-methyl-idene)amino]-phen-yl}methane), four BF4 (-) anions and three CH3CN solvent mol-ecules. The Zn⋯Zn separation is 11.3893 (14) Å and the ligands wrap around the two Zn(II) atoms, forming a triple helix as defined by the Zn-N-N-Zn torsion angles of 104.05 (18), 99.06 (19) and 101.40 (19)°. The Zn-N(pyrid-yl) distances in the octahedral ZnN6 coordination sphere are in the range 2.128 (5)-2.190 (5) Å and the Zn-N(imine) distances are in the range 2.157 (5)-2.277 (5) Å. PMID:26870460

  18. Low-temperature Fabrication of Highly-Efficient, Optically-Transparent (FTO-free) Graphene Cathode for Co-Mediated Dye-Sensitized Solar Cells with Acetonitrile-free Electrolyte Solution

    Kavan, Ladislav; Liska, P.; Zakeeruddin, S. M.; Grätzel, M.

    2016-01-01

    Roč. 195, MAR 2016 (2016), s. 34-42. ISSN 0013-4686 R&D Projects: GA ČR GA13-07724S Institutional support: RVO:61388955 Keywords : dye sensitized solar cell * electrochemical impedance spectroscopy * stainless-steel Subject RIV: CG - Electrochemistry Impact factor: 4.504, year: 2014

  19. Crystal structure of tetrakis[μ2-2-(dimethylamino)ethanolato-κ3N,O:O]di-μ3-hydroxido-dithiocyanato-κ2N-dichromium(III)dilead(II) dithiocyanate acetonitrile monosolvate

    Rusanova, Julia A.; Semenaka, Valentyna V.; Irina V. Omelchenko

    2016-01-01

    The tetranuclear complex cation of the title compound, [Cr2Pb2(NCS)2(OH)2(C4H10NO)4](SCN)2·CH3CN, lies on an inversion centre. The main structural feature of the cation is a distorted seco-norcubane Pb2Cr2O6 cage with a central four-membered Cr2O2 ring. The CrIII ion is coordinated in a distorted octahedron, which involves two N atoms of one bidentate ligand and one thiocyanate anion, two μ2-O atoms of 2-(dimethylamino)ethanolate ligands and two μ3-O atoms of hydroxide ions. The coordination ...

  20. 2-[(2-{Bis[2-(2-hy­droxy-5-nitro­benzyl­idene­amino)­eth­yl]amino}­eth­yl)imino­meth­yl]-4-nitro­phenol acetonitrile monosolvate

    Ha, Kwang

    2010-01-01

    In the title compound, C27H27N7O9·CH3CN, the three nitro groups of the polydentate tripodal Schiff base are located approximately parallel to their respective carrier benzene rings, making dihedral angles of 3.9 (4), 5.0 (4) and 6.3 (4)°. Intra­molecular O—H⋯N hydrogen bonds between the hy­droxy O atoms and the imine N atoms, with O⋯N distances in the range 2.607 (3)–2.665 (3) Å, form nearly planar six-membered rings. In the crystal, weak inter­molecular C—H⋯O and C—H⋯N hydrogen bonds occur a...

  1. Liquid-liquid extraction of plutonium(IV) by dicyclohexano-18-crown-6 from aqueous-organic solutions

    Extraction of Pu(IV) was examined in the presence of several polar water-miscible organic solvents like methanol, ethanol, isobutanol, dioxane, acetone, propylene carbonate (PC) and acetonitrile. The extraction increased several fold with concentrations (up to 30%) of acetonitrile, dioxane, ethanol and PC, but decreases with the addition of acetone, isobutanol and methanol. Maximum enhancement took place in presence of PC and acetonitrile. (orig.)

  2. Trifluoromethanesulfonic acid promoted Dakin-West reaction: An efficient and convenient synthesis of -acetamido ketones

    Ravindra M Kumbhare; Madabhushi Sridhar

    2012-03-01

    Trifluoromethanesulfonic acid promoted efficient condensation of an aromatic aldehyde with an acetophenone and acetonitrile in the presence of acetylchloride as an activator producing -acetamido carbonyl compounds is described.

  3. Organometallic Trinuclear Niobium Cluster Complex in Aqueous Solution: Synthesis and Characterization of Niobium Complexes Containing Nb-3(mu-eta(2):eta(2) (perpendicular to)-NCCH3)(mu(2)-O)(3)(6+) Cluster Core

    Joensen, H.A.N.; Hansson, G. K.; Kozlova, S.G.;

    2010-01-01

    The synthesis and characterization of an organometallic trinuclear oxo-bridged niobium cluster complex with perpendicularly coordinated mu(3)eta(2):eta(2)(perpendicular to)-acetonitrile ligand in aqueous solution is reported. Reaction of NbCl5 in acetonitrile with aluminum under argon followed by...

  4. Towards a thermally regenerative all-copper redox flow battery

    Peljo, Pekka; Lloyd, David; Nguyet, Doan; Majaneva, Marko; Kontturi, Kyosti

    2014-01-01

    An all-copper redox flow battery based on strong complexation of Cu+ with acetonitrile is demonstrated, exhibiting reasonable battery performance. More interestingly, the battery can be charged by heat sources of 100 degrees C, by distilling off the acetonitrile. This destabilizes the Cu+ complex, leading to recovery of the starting materials.

  5. Spectrally resolved femtosecond photon echo spectroscopy of astaxanthin

    Kumar, Ajitesh; Karthick Kumar, S. K.; Gupta, Aditya; Goswami, Debabrata

    2011-08-01

    We have studied the coherence and population dynamics of Astaxanthin solution in methanol and acetonitrile by spectrally resolving their photon echo signals. Our experiments indicate that methanol has a much stronger interaction with the ultrafast dynamics of Astaxanthin in comparison to that of acetonitrile.

  6. Spectrally Resolved Femtosecond Photon Echo Spectroscopy of Astaxanthin

    Kumar, Ajitesh; Kumar, S. K. Karthick; Gupta, Aditya; Goswami, Debabrata

    2011-01-01

    We have studied the coherence and population dynamics of Astaxanthin solution in methanol and acetonitrile by spectrally resolving their photon echo signals. Our experiments indicate that methanol has a much stronger interaction with the ultrafast dynamics of Astaxanthin in comparison to that of acetonitrile.

  7. Study of anomalous mobility of polar molecular solutions by means of the site-site memory equation formalism

    Kobryn, A E; Hirata, F

    2005-01-01

    In this work, the memory equation approach is applied for theoretical study of dynamics of polar molecular liquids described by the interaction site model. The study includes the temperature-density(pressure) dependence of the translational diffusion coefficients D and orientational relaxation times t for infinitely dilute solutions of acetonitrile and methanol in water, and methanol in acetonitrile. Calculations are performed over the range of temperatures and densities employing the SPC/E model for water and optimized site-site potentials for acetonitrile and methanol. Despite an approximate character of the model potentials and closure relation used, the theory is able to reproduce qualitatively all main features of temperature and density dependences of D and t observed in computer and real experiments. In particular, anomalous behavior, i.e. the increase in mobility with density(pressure), is obtained for D and t of methanol in water, while acetonitrile in water or methanol in acetonitrile do not show de...

  8. A New Method of Separation of Four Benzodiazepines by RP-CEC

    Jin Lan ZHANG; Tong Hui ZHOU

    2004-01-01

    A new method to separate diazepam, nitrazepam, estazolam, alprazolam was established on both C18 and C8 CEC columns.The influence of separation voltage, Tris concentration, column temperature and the percentage of acetonitrile on the resolution and retention behavior of four benzodiazepines was investigated.The results showed that the percentage of acetonitrile had the largest effect on the resolution and retention behavior of the four benzodiazepines.Other separation conditions had also effects on the resolution and retention behavior, but smaller than the concentration of acetonitrile.Optimum separation conditions were obtained to separate four benzodiazepines on C18 and C8 CEC columns.

  9. Morphology Control over the Organic Nanoparticles of 1,3-Diphenyl-5-(9-anthryl)-2-pyrazoline

    奚璐; 肖德宝; 杨文胜; 姚建年; 张宝文

    2003-01-01

    The organic nanoparticles of a blue-light-emitting molecule, 1,3-diphenyl-5-(9-anthryl)-2-pyrazuline, were prepared by reprecipitation method using acetonitrile as the solvent for the molecular precursor. Three morphologies, spherical, doughnut-shaped and cubic, could be observed on the silicon substrate forthe nanoparfides by the volume-controlled addition of acetonitrile. The evolution of particle morphology as a function of acetonitrile addition was attributed to the variation of the growth habits of the particles in the different environment. The nanoparticles exhibit the novel photoluminescence spectra as compared to those of monomer and the bulk crystals.

  10. Effect of various solvents on the viscosity-average molecular weight of poly (vinyl acetate)

    Solution polymerization of Vinyl Acetate was carried out in various solvents (benzene, toluene, ethyl acetate, acetonitrile). Dilute solution viscometry was used to determine the viscosity-average molecular weight of the resulting Poly (Vinyl Acetate) (PV Ac) in each case. The viscosity-average molecular weight (M,J of PVAc was found to increase in the order benzene < toluene < ethyl acetate < acetonitrile, It was concluded that under the same reaction conditions (polymerization time, initiator quantity, solvent/monomer ratio, temperature), acetonitrile served as the best solvent for solution. polymerization of Vinyl Acetate monomer. (author)

  11. Facile Routes to Manganese(II) Triflate Complexes

    Riedel, Paul J.; Arulsamy, Navamoney; Mehn, Mark P.

    2011-01-01

    Manganese(II) chloride reacts with trimethylsilyl triflate (TMS(OTf) where OTf = -OSO2CF3) in a 1:1 mixture of acetonitrile and tetrahydrofuran, and after recrystallization affords the linear coordination polymer [MnII(CH3CN)2(OTf)2]n. Each distorted octahedral manganese(II) center in the polymeric chain has trans-acetonitriles and the remaining equatorial coordination positions are occupied by the bridging triflate anions. Dissolving [MnII(CH3CN)2(OTf)2]n in equal volumes of acetonitrile and...

  12. Tin(2) difluoride and antimony(3) trifluoride as fluorine donors in reactions with tantalum halides in various solvents

    The reactions of SnF2, SbF3 with TaF5 and TaCl5 in acetonitrile and dimethylsulfoxide were studied by means of 19F and 119Sn NMR. SnF2 and SbF3 were established to be donors of fluorine ions for the tantalum(5). It was found that the anion and cation tantalum fluorochloride complexes were formed in acetonitrile, and [TaF6]- was dominated in dimethylsulfoxide. In the solution the tin(2) is present as fluorine-containing polymer cations. Dimethylsulfoxide, as distinct from acetonitrile, leads to disproportionation of tantalum fluorochlorides

  13. Analysis of Photodegradation Products of Organic Photochromes by LC/MS

    Young-Hee Lim; Yeu Young Youn; Kyung Hoon Kim; Hye-Sung Cho

    2012-01-01

    The ultraviolet (UV) degradation products of photochromic naphthoxazine and naphthopyran derivatives in acetonitrile were separated and identified using liquid chromatography-mass spectrometry (LC-MS). Photodegradation resulted in oxidation of products.

  14. Reactivity of β-Stannylketones. Elimination vs. Substitution

    Ana Paula Murray; Chopa, Alicia B.

    2000-01-01

    In the present work we report the results obtained in the reaction of β-stannylketones (I) with t-BuONa in dimethylsulfoxide (DMSO) and acetonitrile (ACN) as solvents. The reaction mechanisms probably involved are proposed.

  15. Detailed insights into the retention mechanism of caffeine metabolites on the amide stationary phase in hydrophilic interaction chromatography.

    Guo, Yong; Shah, Rajan

    2016-09-01

    The amide phase was investigated using a wide range of acetonitrile content in the mobile phase in both the HILIC and RPLC modes. Using caffeine metabolites as the model compounds, the retention, thermodynamic and kinetic data was obtained under various mobile phase conditions and supported the previous postulation that there might be a transition of the predominant retention mechanism in relation to the acetonitrile content in HILIC. On the amide phase, hydrophilic partitioning seemed to be the predominant retention mechanism below 85% acetonitrile; and a different retention mechanism (presumably surface adsorption) made more and more significant contributions to the overall retention when the acetonitrile content reached above 85%. This study also provided more direct evidences to explain the effect of salt concentration on the retention of non-charged solutes in HILIC. In addition, the retention, thermodynamic and kinetic data suggest that the amide phase behaved very differently from the conventional C18 phase in the RPLC mode. PMID:27522153

  16. Effect of some organic solvents on oxidative phosphorylation in rat liver mitochondria

    Syed, Muzeeb; Skonberg, Christian; Hansen, Steen Honoré

    2013-01-01

    The effect of acetone, acetonitrile, dimethyl sulfoxide (DMSO), ethanol and methanol on oxidative phosphorylation (ATP synthesis) in rat liver mitochondria has been studied. All the organic solvents inhibited the oxidative phosphorylation in a concentration dependent manner, but with differences in...... potencies. Among the tested organic solvents, acetonitrile and acetone were more potent than ethanol, methanol, and DMSO. There was no significant difference in oxidative phosphorylation, compared to controls, when the concentrations of acetone was below 1% (v/v), of acetonitrile below 2% (v/v), of DMSO...... below 10% (v/v), of ethanol below 5% or of methanol below 2%, respectively. There was complete inhibition of oxidative phosphorylation at 50% (v/v) of acetone, acetonitrile and ethanol. But in the case of DMSO and methanol there were some residual activities observed at the 50% concentration level. DMSO...

  17. Deprotection of oximes using urea nitrate under microwave irradiation

    P T Perumal; M Anniyappan; D Muralidharan

    2004-08-01

    A new mild and efficient method for the cleavage of oximes to carbonyl compounds using readily available urea nitrate in acetonitrile-water (95 : 5), under microwave irradiation within 2 min, in good yields is reported.

  18. Two Chromatographic Methods for the Determination of Some Antimigraine Drugs

    El-Bagary, Ramzia I.; Mohammed, Nashwah G.; Nasr, Heba A.

    2012-01-01

    Two stability indicating chromatographic methods were proposed for the determination of almotriptan, eletriptan, and rizatriptan, in presence of their acid degradation products. The first method is a quantitative densitometric thin layer chromatography. The developing systems were; acetonitrile: methanol: dichloromethane: ammonia (10:6:3:1 v/v), ethyl acetate: methanol: ammonia (15:4:1 v/v), and methanol: acetonitrile: ammonia (9:4:1 v/v) for almotriptan, eletriptan and rizatriptan respective...

  19. Optimizing the lifetimes of phenoxonium cations derived from vitamin E via structural modifications.

    Yue, Yanni; Novianti, Maria L; Tessensohn, Malcolm E; Hirao, Hajime; Webster, Richard D

    2015-12-28

    Systematic synthesis of a number of new phenolic compounds with structures similar to vitamin E led to the identification of several sterically hindered compounds that when electrochemically oxidised in acetonitrile in a -2e(-)/-H(+) process formed phenoxonium diamagnetic cations that were resistant to hydrolysis reactions. The reactivity of the phenoxonium ions was ascertained by performing cyclic voltammetric scans during the addition of carefully controlled quantities of water into acetonitrile solutions, with the data modelled using digital simulation techniques. PMID:26480893

  20. A rapid, solid phase extraction (SPE) technique for the extraction and gas chromatographic determination lindane pesticide residue in tissue and milk

    Yuningsih; Sri Yuliastuti

    2006-01-01

    Organochlorine pesticide contamination in feed can cause residue in animal product (tissue and milk), so its become a problem in food safety. Solid phase extraction (SPE) has been carried out for determination organochlorine pesticide residues in food animal production. The technique was rapid, not costly and produce limited amount of hazardous-waste. Samples were homogenized with acetonitrile trough cartridge C18, eluted in fluorocyl column with 2% ether-petroleum or acetonitrile fortissue a...

  1. Solvation of Nucleosides in Aqueous Mixtures of Organic Solvents: Relevance to DNA Open Basepairs

    Ababneh, Anas M.; Large, C. C.; Georghiou, S

    2003-01-01

    Toward the goal of understanding how open basepairs in DNA interact with their heterogeneous environment, we have studied the steady-state intrinsic fluorescence properties of the purine and pyrimidine deoxynucleosides in organic solvents in the presence of small amounts of water. The organic solvents used in the present study were: n-butanol, acetonitrile, methanol, n-propanol, isopropanol, and isobutanol. For n-butanol and acetonitrile, which have a high degree of amphiphilicity and weak hy...

  2. MODELING AND SIMULATION OF A BATCH DISTILLATION COLUMN FOR RECOVERING LIMONENE EPOXIDE MODELAGEM E SIMULAÇÃO DE UMA COLUNA DE DESTILAÇÃO POR LOTES PARA RECUPERAR EPÓXIDO DE LIMONENO

    Rolando Barrera Zapata; Aída Luz Villa; Consuelo Montes de Correa

    2012-01-01

    Aspen Plus and MATLAB software simulation tools were employed for modeling, simulation and optimization of a distillation process to recover limonene epoxide from a liquid mixture containing limonene + acetonitrile + water + limonene epoxide. This mixture is obtained from limonene epoxidation over PW-Amberlite using aqueous hydrogen peroxide as oxidant and acetonitrile as solvent. Analyses of residue curve maps indicate that batch distillation columns of inverse configuration are adequate to ...

  3. NMR study of the reactions of tin(2) difluoride and antimony(3) trifluoride with niobium pentachloride

    Interaction of SnF2 and SbF3 with NbCl5 in solutions of acetonitrile and dimethylsulfoxide was studied by the method of 19F, 93Nb, 119Sn NMR. It is shown that anionic octahedral chlorofluoride complexes of niobium are formed in acetonitrile, while neutral ones- in dimethylsulfoxide. SnF2 and SnF3 are effective sources of fluorine ions when preparing fluorochloride and fluoride compounds of niobium

  4. Aspects of Optimisation of Separation of Drugs by Chemometrics

    Harang, Valérie

    2003-01-01

    Statistical experimental designs have been used for method development and optimisation of separation. Two reversed phase HPLC methods were optimised. Parameters such as the pH, the amount of tetrabutylammonium (TBA; co-ion) and the gradient slope (acetonitrile) were investigated and optimised for separation of erythromycin A and eight related compounds. In the second method, a statistical experimental design was used, where the amounts of acetonitrile and octane sulphonate (OSA; counter ion)...

  5. Influence of salt ions on binding to molecularly imprinted polymers.

    Kempe, Henrik; Kempe, Maria

    2010-01-01

    Salt ions were found to have an influence on template binding to two model molecularly imprinted polymers (MIPs), targeted to penicillin G and propranolol, respectively, in water-acetonitrile mixtures. Water was detrimental to rebinding of penicillin G whereas propranolol bound in the entire water-acetonitrile range tested. In 100% aqueous solution, 3-M salt solutions augmented the binding of both templates. The effects followed the Hofmeister series with kosmotropic ions promoting the larges...

  6. Comparison of iso-eluotropic mobile phases at different temperatures for the separation of triacylglycerols in Non-Aqueous Reversed Phase Liquid Chromatography.

    Hmida, Dorra; Abderrabba, Manef; Tchapla, Alain; Héron, Sylvie; Moussa, Fathi

    2015-05-15

    Triacylglycerols (TAGs) are a large class of neutral lipids that naturally occur in both plant and animal oils and fats. Their analyses in Non-Aqueous Reversed Phase Liquid Chromatography (NARP) require a mixture of weak solvent (mostly acetonitrile) and strong solvent. In the present work, we have established eluotropic solvent strength scale of several binary mobile phases on C18 bonded silica at different temperatures (acetonitrile/methylene chloride, acetonitrile/acetone, acetonitrile/ethyl acetate, acetonitrile/propan-2-ol, and acetonitrile/butan-1-ol at 25°C, 43°C, 63°C and 85°C); it is based on the methylene selectivity and the use of homologous series. We show that this scale is well suited to the TAGs analysis. The analysis of nine seed oils (Aleurites fordii, Calophyllum inophyllum, Glycina max, Olea europea, Orbignya olifeira, Pinus koraiensis, Pistacia lentiscus, Punica granatum and Ribes nigrum) in iso-eluotropic conditions leads to propose unambiguously the couple MeCN/BuOH at 25°C as the best system to separate TAGs. The use of butanol, as strong solvent, provides very good TAGs congeners separations and avoids the use of chlorinated solvents which gave to this day the best separations. PMID:25855317

  7. Modelling of the effect of solute structure and mobile phase pH and composition on the retention of phenoxy acid herbicides in reversed-phase high-performance liquid chromatography

    A feed-forward artificial neural network (ANN) learned by error back-propagation is used to generate a retention predictive model for phenoxy acid herbicides in isocratic reversed-phase high-performance liquid chromatography. The investigated solutes (18 compounds), apart from the most common herbicides of this class, include some derivatives of benzoic acid and phenylacetic acid structurally related to phenoxy acids, as a whole covering a pKa range between 2.3 and 4.3. A mixed model in terms of both solute descriptors and eluent attributes is built with the aim of predicting retention in water-acetonitrile mobile phases within a large range of composition (acetonitrile from 30% to 70%, v/v) and acidity (pH of water before mixing with acetonitrile ranging between 2 and 5). The set of input variables consists of solute pKa and quantum chemical molecular descriptors of both the neutral and dissociated form, %v/v of acetonitrile in the mobile phase and pH of aqueous phase before mixing with acetonitrile. After elimination of redundant variables, a nine-dimensional model is identified and its prediction ability is evaluated by external validation based on three solutes not involved in model generation and by cross-validation. A multilinear counterpart in terms of the same descriptors is seen to provide a noticeably poorer retention prediction

  8. [Deep eutectic solvent: a new kind of mobile phase modifier for hydrophilic interaction liquid chromatography].

    Tan, Ting; Qiao, Xin; Wan, Yiqun; Qiu, Hongdeng

    2015-09-01

    Deep eutectic solvents (DESs) were used as a new kind of mobile phase modifier in hydrophilic interaction liquid chromatography (HILIC). In our experiment, a SiO2 column (150 mm x 4.6 mm, 3 µm) was selected to separate several nucleobases and nucleosides by using the mixed solution of acetonitrile and DES (choline chloride-ethylene glycol (1:3, mol/mol) ) as mobile phase. Subsequently, the concentrations of DESs in acetonitrile and the column temperature on the effect of separation were investigated. According to the experimental results, better separation of nucleobases and nucleosides was obtained by using acetonitrile and DESs mixed solution as mobile phase than that using traditional water-based solution. For example, a baseline separation between cytosine and cytidine cannot be achieved by HILIC with water-based mobile phase, however, greater improvement was gained by HILIC with modified DES-acetonitrile mobile phase. Meanwhile, the retention times of nucleobases and nucleosides decreased as the proportion of DESs in acetonitrile increased, the most significant decrease of which was with cytidine. Similar retention behavior took place with the effect of column temperature. Decreased retention times of the analytes were observed as column temperature increased. The experimental results indicated that this new method may solve some separation difficulties in traditional water-based HILIC, which also successfully verify the feasibility of DESs as mobile phase modifiers. PMID:26753279

  9. Synthesis, characterization, and reactivity of furan- and thiophene-functionalized bis(n-heterocyclic carbene) complexes of iron(II)

    Rieb, Julia

    2014-09-15

    The synthesis of iron(II) complexes bearing new heteroatom-functionalized methylene-bridged bis(N-heterocyclic carbene) ligands is reported. All complexes are characterized by single-crystal X-ray diffraction (SC-XRD), nuclear magnetic resonance (NMR) spectroscopy, and elemental analysis. Tetrakis(acetonitrile)-cis-[bis(o-imidazol-2-ylidenefuran)methane]iron(II) hexafluorophosphate (2a) and tetrakis(acetonitrile)-cis-[bis(o-imidazol-2-ylidenethiophene)methane]iron(II) hexafluorophosphate (2b) were obtained by aminolysis of [Fe{N(SiMe3)2}2(THF)] with furan- and thiophene-functionalized bis(imidazolium) salts 1a and 1b in acetonitrile. The SC-XRD structures of 2a and 2b show coordination of the bis(carbene) ligand in a bidentate fashion instead of a possible tetradentate coordination. The four other coordination sites of these distorted octahedral complexes are occupied by acetonitrile ligands. Crystallization of 2a in an acetone solution by the slow diffusion of Et2O led to the formation of cisdiacetonitriledi[ bis(o-imidazol-2-ylidenefuran)methane]iron(II) hexafluorophosphate (3a) with two bis(carbene) ligands coordinated in a bidentate manner and two cis-positioned acetonitrile molecules. Compounds 2a and 2b are the first reported iron(II) carbene complexes with four coordination sites occupied by solvent molecules, and it was demonstrated that those solvent ligands can undergo ligand-exchange reactions.

  10. Study of molecular-colloidal solutions of C70 fullerene: structural features, optical and nonlinear-optical properties

    Nonlinear optical rotation of elliptically polarized laser pulses (λ = 532 nm, τFWHM ∼ 12 ns) in benzene, toluene, and binary (toluene+acetonitrile) solutions of fullerene C70 - D5h(6) has been experimentally investigated. Features of (C70)n clusters' structure have been studied using high-resolution transmission electron microscopy in toluene+acetonitrile mixtures and the fractal mechanism of formation of the large (∼ 280.0 nm) stable clusters in solution, which may contain up to ∼ 16807 molecules of C70 is proposed. It has been demonstrated that the C70 cluster sizes depend on initial concentration of C70, as well as volume fraction of acetonitrile in solvent mixture. Correlations between the processes of nonlinear rotation of polarization ellipse, change of electronic absorption spectra and C70 clusters formation in solutions have been demonstrated. Physical mechanisms of laser induced optical activity in C70 solutions have been discussed. The values of the nonlinear Kerr coefficient (n2) and nonlinear susceptibility component (χxyyx(3)(ω) ) of C70 solutions in toluene, benzene with various polarization ellipticity θ = 0.2†0.8, and toluene+acetonitrile at different concentrations of C70 for various volume fractions of acetonitrile have been determined. (authors)

  11. NMR study into reactions of vanadium- and tungsten oxohalogenides with alcohols

    PMR spectra of WOX4 (X=F, Cl) and VOCl3 with methyl and ethyl alcohols in acetonitrile or carbon tetrachloride have been investigated. Interaction of vanadium oxotrichloride with ROH at a ratio ROH:VOCl3=1;2 or 3 yields mono-, di-, or trialkoxide of vanadile. Association of the molecules VO(OCH3)3 in chloroform through metoxygroups has been assumed. The solutions of WOCl4 and ROH in acetonitrile contain alkoxycomplexes with a different substitution degree of chlorine atoms which have certain signals in 1H spectra. It has been shown that interaction of tungsten oxotetrachloride with an excess methyl alcohol gives trimetoxychlorides along with mono- and dimethyloxychlorides of tungsten. It has been established that hydrogen chloride, liberated in alkoholysis of tungsten oxotetrachloride, causes in the presence of alcohol saponification of acetonitrile with the formation of esters

  12. Influence of physico-chemical parameters of some barbituric acid derivatives on their retention on an amide embedded RP silica column.

    Jakab, Annamaria; Prodan, Miklos; Forgács, Esther

    2002-03-01

    Retention parameters of 45 different barbituric acid derivatives were determined on an amide embedded RP silica column (Discovery RP-AmideC16) using non-buffered water-acetonitrile eluent systems. Linear correlation were calculated between the logarithm of the capacity factor and the acetonitrile concentration in the eluent. To determine the retention behavior of barbituric acid derivatives, stepwise regression analysis (SRA) and principal component analysis (PCA) followed by two-dimensional nonlinear and modified nonlinear mapping was used. It can be concluded, the retention of barbituric acid derivatives are governed mainly by the steric parameters of the substituents. Principal component analysis indicated that the barbituric acid derivatives have mixed retention on this amide embedded RP silica column in water-acetonitrile eluent. PMID:11836055

  13. Direct-immersion solid-phase microextraction coupled to fast gas chromatography mass spectrometry as a purification step for polycyclic aromatic hydrocarbons determination in olive oil.

    Purcaro, Giorgia; Picardo, Massimo; Barp, Laura; Moret, Sabrina; Conte, Lanfranco S

    2013-09-13

    The aim of the present work was to optimize a preparation step for polycyclic aromatic hydrocarbons in a fatty extract. Solid-phase microextraction is an easy preparation technique, which allows to minimize solvent consumption and reduce sample manipulation. A Carbopack Z/polydimethylsiloxane fiber, particularly suitable for extraction of planar compounds, was employed to extract polycyclic aromatic hydrocarbons from a hexane solution obtained after a previous extraction with acetonitrile from oil, followed by a liquid-liquid partition between acetonitrile and hexane. The proposed method was a rapid and sensitive solution to reduce the interference of triglycerides saving the column life and avoiding frequent cleaning of the mass spectrometer ion source. Despite the non-quantitative extraction of polycyclic aromatic hydrocarbons from oil using acetonitrile, the signal-to-noise ratio was significantly improved obtaining a limit of detection largely below the performance criteria required by the European Union legislation. PMID:23915642

  14. The examination of berberine excited state by laser flash photolysis

    Cheng, Lingli; Wang, Mei; Zhao, Ping; Zhu, Hui; Zhu, Rongrong; Sun, Xiaoyu; Yao, Side; Wang, Shilong

    2009-07-01

    The property of the excited triplet state of berberine (BBR) was investigated by using time-resolved laser flash photolysis of 355 nm in acetonitrile. The transient absorption spectra of the excited triplet BBR were obtained in acetonitrile, which have an absorption maximum at 420 nm. And the ratio of excitation to ionization of BBR in acetonitrile solvent was calculated. The self-decay and self-quenching rate constants, and the absorption coefficient of 3BBR* were investigated and the excited state quantum yield was determined. Furthermore utilizing the benzophenone (BEN) as a triplet sensitizer, and the β-carotene (Car) as an excited energy transfer acceptor, the assignment of 3BBR* was further confirmed and the related energy transfer rate constants were also determined.

  15. Analysis of 19 PCB congeners in catfish tissue using a modified QuEChERS method with GC-MS/MS.

    Chamkasem, Narong; Lee, Sookwang; Harmon, Tiffany

    2016-02-01

    A simple approach to determine 19 PCB congeners in catfish tissue was presented. A modified QuEChERS method employing high solvent to sample ratio 10:1 was used to improve the extraction recovery of 19 PCB congeners. After salting out by shaking with anhydrous magnesium sulfate and sodium chloride, 1 mL of acetonitrile extract was pipetted into a 2-mL centrifuge tube containing anhydrous magnesium sulfate, primary secondary amine sorbent, and C-18 sorbent. The tube was then shaken and centrifuged to absorb fat and fatty acid residue present in the acetonitrile extract. The acetonitrile extract was analyzed by GC-MS/MS. The excellent sensitivity of GC-MS/MS allows for the direct injection of the samples to detect the low level of the PCB congeners. The method therefore is high throughput, uses fewer consumable lab supplies, and provides excellent sensitivity with an LOQ below 1 ng/g. PMID:26304427

  16. Measurement and correlation of solubility of Tetracycline hydrochloride in six organic solvents

    Highlights: ► The solubility of Tetracycline hydrochloride (TCH) in six organic solvents was determined. ► Apelblat, NRTL and UNIQUAC models were used to correlate the experimental data. ► Superior correlation was achieved with NRTL model. - Abstract: The solubility of Tetracycline hydrochloride (TCH) in methanol, ethanol, 1-propanol, 1-butanol, acetone, and acetonitrile, was measured using a static method from (283.15 to 318.15) K. The solubility of TCH decreased in the order of methanol, ethanol, 1-propanol, 1-butanol, acetone, and acetonitrile. With increasing temperature, the solubility of TCH increased in ethanol, 1-propanol, 1-butanol, acetone, and acetonitrile but decreased in methanol. Moreover, the experimental solubility data were correlated by the modified Apelblat equation, NRTL and UNIQUAC models, respectively. And the calculated data by NRTL model showed better agreement with experimental values than the modified Apelblat equation and UNIQUAC model.

  17. Solvent extraction of plutonium(IV) by sulphoxides from mixed aqueous-organic media

    Extraction behaviour of plutonium(IV) from nitric acid media by two long-chain aliphatic sulphoxides, namely, di-hexylsulphoxide and di-n-octylsulphoxide has been investigated in the presence of several water-miscible organic solvents to study their possible synergistic effect on metal ion extraction. Methanol, ethanol, n - and isopropanol, dioxane, acetone as well as acetonitrile were used as the organic components of the mixed (polar) phase. These additives affected the extraction to varying degrees. Thus, extractability of Pu increases 2-3 fold with increasing concentration (upto 20%) of acetonitrile, acetone, methanol and ethanol while it decreases with increasing concentration of n- and isopropanol. At high concentration of the former, the synergism changes into antagonism. Possible reasons for such behaviour are briefly discussed. Among these organic additives, maximum enhancement in the extraction of Pu(IV) was observed in the presence of acetonitrile. The relative increase in extraction was found to be more at lower sulphoxide concentrations. (author)

  18. Volatile compounds from leaves of the African spider plant (Gynandropsis gynandra) with bioactivity against spider mite (Tetranychus urticae)

    Nyalala, Samuel Odeyo; Petersen, Mikael Agerlin; Grout, Brian William Wilson

    2013-01-01

    volatile compounds were emitted by G. gynandra at significantly higher levels than mite-susceptible pot roses, including isothiocyanates, aldehydes, esters, alcohols and terpenes. Six representative compounds were selected to assess bioactivity. Spider mite populations were completely inactive after a 2¿h......Previous studies have demonstrated that Gynandropsis gynandra emits acetonitrile as a foliar volatile from intact plants and isolated leaves, and that this compound is an effective spider mite repellent. This study has used gas chromatography–mass spectrometry to investigate volatile compounds...... emitted from homogenised G. gynandra leaves to evaluate their tissue acetonitrile content and to look for other compounds that might be exploited for the management of spider mites. Acetonitrile was absent from the homogenised tissues of five lines of G. gynandra, studied over two seasons. Thirteen...

  19. Effects of acid concentration on intramolecular charge transfer reaction of 4-(azetidinyl) benzonitrile in solution

    Biswajit Guchhait; Tuhin Pradhan; Ranjit Biswas

    2014-01-01

    Effects of acid concentration on excited state intramolecular charge transfer reaction of 4-(azetidinyl) benzonitrile (P4C) in aprotic (acetonitrile and ethyl acetate) and protic (ethanol) solvents have been studied by means of steady state absorption and fluorescence, and time resolved fluorescence spectroscopic techniques. While absorption and fluorescence bands of P4C have been found to be shifted towards higher energy with increasing acid concentration in acetonitrile and ethyl acetate, no significant dependence has been observed in ethanolic solutions. Reaction rate becomes increasingly slower with acid concentration in acetonitrile and ethyl acetate. In contrast, acid in ethanolic solutions does not produce such an effect on reaction rate. Time-dependent density functional theory calculations have been performed to understand the observed spectroscopic results.

  20. Validação de método analítico livre de acetonitrila para análise de microcistinas por cromatografia líquida de alta eficiência

    Sérvio Túlio Alves Cassini

    2013-01-01

    Full Text Available Blooms of cyanobacteria represent a public health risk due to their cyanotoxins such as microcystins. Liquid chromatography techniques to separate and quantify microcystins invariably use acetonitrile as the organic component of the mobile phase. The price and availability of acetonitrile together with its elevated toxicity encourage the validation of acetonitrile-free methods of microcystin analysis. In this work, methanol was employed as the organic solvent of the mobile phase and the validation method was performed with different environmental water samples. The method showed limits of detection between 0.17 and 0.25 µg/L and of quantification between 0.55 and 0.82 µg/L for the microcystin variants: -RR, -YR, -LR, -LA.

  1. Stable Isotope-Assisted Evaluation of Different Extraction Solvents for Untargeted Metabolomics of Plants

    Maria Doppler

    2016-06-01

    Full Text Available The evaluation of extraction protocols for untargeted metabolomics approaches is still difficult. We have applied a novel stable isotope-assisted workflow for untargeted LC-HRMS-based plant metabolomics , which allows for the first time every detected feature to be considered for method evaluation. The efficiency and complementarity of commonly used extraction solvents, namely 1 + 3 (v/v mixtures of water and selected organic solvents (methanol, acetonitrile or methanol/acetonitrile 1 + 1 (v/v, with and without the addition of 0.1% (v/v formic acid were compared. Four different wheat organs were sampled, extracted and analysed by LC-HRMS. Data evaluation was performed with the in-house-developed MetExtract II software and R. With all tested solvents a total of 871 metabolites were extracted in ear, 785 in stem, 733 in leaf and 517 in root samples, respectively. Between 48% (stem and 57% (ear of the metabolites detected in a particular organ were found with all extraction mixtures, and 127 of 996 metabolites were consistently shared between all extraction agent/organ combinations. In aqueous methanol, acidification with formic acid led to pronounced pH dependency regarding the precision of metabolite abundance and the number of detectable metabolites, whereas extracts of acetonitrile-containing mixtures were less affected. Moreover, methanol and acetonitrile have been found to be complementary with respect to extraction efficiency. Interestingly, the beneficial properties of both solvents can be combined by the use of a water-methanol-acetonitrile mixture for global metabolite extraction instead of aqueous methanol or aqueous acetonitrile alone.

  2. Stable Isotope-Assisted Evaluation of Different Extraction Solvents for Untargeted Metabolomics of Plants

    Doppler, Maria; Kluger, Bernhard; Bueschl, Christoph; Schneider, Christina; Krska, Rudolf; Delcambre, Sylvie; Hiller, Karsten; Lemmens, Marc; Schuhmacher, Rainer

    2016-01-01

    The evaluation of extraction protocols for untargeted metabolomics approaches is still difficult. We have applied a novel stable isotope-assisted workflow for untargeted LC-HRMS-based plant metabolomics , which allows for the first time every detected feature to be considered for method evaluation. The efficiency and complementarity of commonly used extraction solvents, namely 1 + 3 (v/v) mixtures of water and selected organic solvents (methanol, acetonitrile or methanol/acetonitrile 1 + 1 (v/v)), with and without the addition of 0.1% (v/v) formic acid were compared. Four different wheat organs were sampled, extracted and analysed by LC-HRMS. Data evaluation was performed with the in-house-developed MetExtract II software and R. With all tested solvents a total of 871 metabolites were extracted in ear, 785 in stem, 733 in leaf and 517 in root samples, respectively. Between 48% (stem) and 57% (ear) of the metabolites detected in a particular organ were found with all extraction mixtures, and 127 of 996 metabolites were consistently shared between all extraction agent/organ combinations. In aqueous methanol, acidification with formic acid led to pronounced pH dependency regarding the precision of metabolite abundance and the number of detectable metabolites, whereas extracts of acetonitrile-containing mixtures were less affected. Moreover, methanol and acetonitrile have been found to be complementary with respect to extraction efficiency. Interestingly, the beneficial properties of both solvents can be combined by the use of a water-methanol-acetonitrile mixture for global metabolite extraction instead of aqueous methanol or aqueous acetonitrile alone. PMID:27367667

  3. Synthesis and characterization of an iron complex bearing a cyclic tetra-N-heterocyclic carbene ligand: An artifical heme analogue?

    Anneser, Markus R.

    2015-04-20

    An iron(II) complex with a cyclic tetradentate ligand containing four N-heterocyclic carbenes was synthesized and characterized by means of NMR and IR spectroscopies, as well as by single-crystal X-ray structure analysis. The iron center exhibits an octahedral coordination geometry with two acetonitrile ligands in axial positions, showing structural analogies with porphyrine-ligated iron complexes. The acetonitrile ligands can readily be substituted by other ligands, for instance, dimethyl sulfoxide, carbon monoxide, and nitric oxide. Cyclic voltammetry was used to examine the electronic properties of the synthesized compounds. © 2015 American Chemical Society.

  4. Development and validation of stability-indicating HPLC method for betamethoasone dipropionate and related substances in topical formulation

    Vairale, A. S.; P Sivaswaroop; Bandana, S.

    2012-01-01

    A gradient reversed phase HPLC method was developed and validated for analysis of betamethasone dipropionate, its related substances and degradation products, using Altima C 18 column (250×4.6 mm, 5 μm) with a flow rate of 1.0 ml/min and detection wavelength of 240 nm. The mobile phase A is a mixture of water, tetrahydrofuran and acetonitrile in the ratio of 90:4:6 (v/v/v) while mobile phase B is a mixture of acetonitrile, tetrahydrofuran, water and methanol in the ratio of 74:2:4:20 (v/v/v/v...

  5. Estimation of thermodynamic acidity constants of some penicillinase-resistant penicillins.

    Demiralay, Ebru Çubuk; Üstün, Zehra; Daldal, Y Doğan

    2014-03-01

    In this work, thermodynamic acidity constants (pssKa) of methicillin, oxacillin, nafcillin, cloxacilin, dicloxacillin were determined with reverse phase liquid chromatographic method (RPLC) by taking into account the effect of the activity coefficients in hydro-organic water-acetonitrile binary mixtures. From these values, thermodynamic aqueous acidity constants of these drugs were calculated by different approaches. The linear relationships established between retention factors of the species and the polarity parameter of the mobile phase (ET(N)) was proved to predict accurately retention in LC as a function of the acetonitrile content (38%, 40% and 42%, v/v). PMID:24412696

  6. Validation and statistical analysis of two high performance liquid chromatography methods for the determination of indinavir sulfate raw material and capsules

    Breno de Carvalho e Silva; Lígia Maria Moreira de Campos; Elzíria de Aguiar Nunan; Cristina Duarte Vianna Soares; Gisele Rodrigues Silva; Jóse Antônio de Aquino Ribeiro; Gerson Antônio Pianetti

    2005-01-01

    Two high performance liquid chromatography (HPLC) methods for the quantitative determination of indinavir sulfate were tested, validated and statistically compared. Assays were carried out using as mobile phases mixtures of dibutylammonium phosphate buffer pH 6.5 and acetonitrile (55:45) at 1 mL/min or citrate buffer pH 5 and acetonitrile (60:40) at 1 mL/min, an octylsilane column (RP-8) and a UV spectrophotometric detector at 260 nm. Both methods showed good sensitivity, linearity, precision...

  7. Determination of atorvastatin and gemfibrozil in human plasma by reversed-phase liquid chromatography

    Khan, Islam U.; Ashfaq, Muhammad

    2010-01-01

    A simple, sensitive and reproducible RP-HPLC method was developed and validated for the simultaneous determination of atorvastatin and gemfibrozil in human plasma. After a single step liquidliquid extraction of both the drugs with acetonitrile, the separation was accomplished on a Merck C 18 column (250 x 4.6, 5 µm). Diode array detection at a wavelength of 240 nm was carried out with a mobile phase comprising of a mixture of 0.1M ammonium acetate buffer (pH 5.0) and acetonitrile in the...

  8. Oxidation of saturated hydrocarbons with peroxyacetic acid catalyzed by vanadium complexes

    Gonzalez Cuervo, Laura; Kozlov, Yuriy N.; Süss-Fink, Georg; Shul’pin, Georgiy B.

    2009-01-01

    Peroxyacetic acid (PAA) oxidizes alkanes in acetonitrile or acetic acid at 60 °C if a soluble vanadium(V) salt, n-Bu4NVO3 (1), is used as a catalyst. Corresponding ketones, alcohols and alkyl hydroperoxides are the main products. Methane, ethane, propane, cyclohexane, and other higher alkanes were substrates in the oxidations. The proposed mechanism involves the formation of a complex between (1) and PAA with equilibrium constants 3.3 and 6.8 dm3 mol−1 for acetonitrile and acetic acid as solv...

  9. Simultaneous screening and quantification of 52 common pharmaceuticals and drugs of abuse in hair using UPLC-TOF-MS

    Nielsen, Marie Katrine Klose; Johansen, Sys Stybe; Dalsgaard, Petur Weihe;

    2010-01-01

    An UPLC-TOF-MS method for simultaneous screening and quantification of 52 drugs in hair was developed and validated. The selected drugs represent the most common classes of pharmaceuticals and drugs of abuse such as amphetamines, analgesics, antidepressants, antipsychotics, benzodiazepines, cocaine......, ketamine and opioids. Hair samples were extracted with methanol:acetonitrile:ammonium formate (2 mM, 8% acetonitrile, pH 5.3) overnight at 37 degrees C. The target drugs were separated and quantified using a Waters ACQUITY UPLC coupled to a Waters Micromass LCT Premier XE Time-of-Flight mass spectrometer...

  10. Bithiophene radical cation: Resonance Raman spectroscopy and molecular orbital calculations

    Grage, M.M.-L.; Keszthelyi, T.; Offersgaard, J.F.; Wilbrandt, R.

    1998-01-01

    The resonance Raman spectrum of the photogenerated radical cation of bithiophene is reported. The bithiophene radical cation was produced via a photoinduced electron transfer reaction between excited bithiophene and the electron acceptor fumaronitrile in a room temperature acetonitrile solution a...... the Raman spectrum excited in resonance with the absorption band at 425 nm. The spectrum was interpreted with the help of density functional theory calculations. (C) 1998 Elsevier Science B.V.......The resonance Raman spectrum of the photogenerated radical cation of bithiophene is reported. The bithiophene radical cation was produced via a photoinduced electron transfer reaction between excited bithiophene and the electron acceptor fumaronitrile in a room temperature acetonitrile solution and...