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Sample records for carbazides

  1. Detection of oxygen species generated by WO3 modification fullerene/TiO2 in the degradation of 1,5-diphenyl carbazide

    International Nuclear Information System (INIS)

    Highlights: • Reactive oxygen species were detected through oxidation reaction from DPCI to DPCO. • Generated reactive oxygen species and hydroxyl radicals can be analysed by DPCI degradation. • C60 have good effect in photo/ultrasonic degradation process. • Enhanced adsorption capacity can increase the degradation effect. • Photocatalytic activity attributed to photo-absorption effect by C60 and cooperative effect of WO3 and TiO2. - Abstract: In the present work, powders with different relative mole ratios of WO3-fullerene/TiO2 were irradiated by visible light and ultrasonic. The composite obtained was characterized by BET surface area measurements, X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), fourier transform infrared (FT-IR), transmission electron microscopy (TEM) and UV–vis analysis. A methylene blue (MB) solution under visible light and ultrasonic irradiation was used to determine the catalytic activity. The generation of reactive oxygen species were detected through the oxidation reaction from 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). Finally, we performed experiments to find the optimum relative mole ratio of fullerene for the degradation of MB

  2. Inhibitory effect of some carbazides on corrosion of aluminium in hydrochloric acid and sodium hydroxide solutions

    Energy Technology Data Exchange (ETDEWEB)

    Fouda, A.S. [El-Mansoura Univ. (Egypt). Dept. of Chemistry; Madkour, L.H. [Tanta Univ. (Egypt). Dept. of Chemistry; Elshafei, A.A. [El-Mansoura Univ. (Egypt). Dept. of Chemistry; Elasklany, A.H. [El-Mansoura Univ. (Egypt). Dept. of Chemistry

    1995-06-01

    The dissolution of aluminium in hydrochloric acid and sodium hydroxide solutions in the presence of semicarbazide, thiosemicarbazide and sym.diphenylcarbazide as corrosion inhibitors has been studied using thermometric, weight-loss and polarization methods. The three methods gave consistent results. The higher inhibition efficiency of these compounds in acidic than in alkaline madia may be due to the less negative potential of aluminium in hydrochloric acid solution, favouring adsorption of the additive. The adsorption of these compounds were found to obey Frumkin adsorption isotherm. Cathodic polarization measurements showed that these compounds are cathodic inhibitors and their adsorption in the double layer does not change the mechanism of the hydrogen evolution reaction. The results are analysed in terms of both molecular and cationic adsorption. (orig.)

  3. [Selenazoles. XII. (1) Reaction of 4-(p-tolyl)-selenosemi-carbazides of acetic, benzoic, isonicotinic, nicotinic and picolinic acid with omega-acetophenone].

    Science.gov (United States)

    Biliński, S; Bielak, L; Chmielewski, J; Marcewicz-Rojewska, B; Musik, I

    1989-01-01

    The cyclization of 4-(p-tolyl)-selenosemicarbazides of acetic, benzoic, isonicotinic, nicotinic and picolinic acids (Ia-e) with omega-bromoacetophenone was investigated in the medium of methanol (Method A) or in methanol in the presence of anhydrous sodium acetate (Method B). Acid hydrolysis of compounds IIf-i and IVa-c, e was studied. Results of UV and IR spectrometric measurements and of the in vitro microbiological studies are presented. In contradistinction to corresponding thiosemicarbazides, the change in N4 nitrogen atom basicity of the parent selenosemicarbazide I (pKa of p-toluidine = 5.1), in comparison to that of 4-phenyl-selenosemicarbazide (pKa of aniline = 4.63), proved to influence the equilibrium of the reaction with omega-bromoacetophenone only in the methanol medium without addition of anhydrous sodium acetate (Method A).

  4. BIOSORPTION OF CHROMIUM (VI) FROM INDUSTRIAL EFFLUENT BY WILD ANDMUTANT TYPE STRAIN OF SACCHAROMYCES CEREVISIAE AND ITS IMMOBILIZED FORM

    OpenAIRE

    K Selvam, K Arungandhi, B Vishnupriya, T Shanmuga priya and M Yamuna

    2013-01-01

    Biosorption of chromium was studied by wild type Saccharomyces cerevisiae strain, mutant strain, immobilized-wild type and mutant strain. Chromium absorption pattern was observed in all experimental conditions. Hexavalent chromium (VI) was analyzed by diphenyl carbazide method, by oxidizing the trivalent chromium (III). The percentage efficiency of wild type S. cerevisiae and its mutant strain, immobilized-wild type and mutant strain were 94.8%, 98.7%, 97.4% and 100% respectively. S. cerevisi...

  5. Rhodamine B degradation and reactive oxygen species generation by a ZnSe-graphene/TiO2 sonocatalyst

    Institute of Scientific and Technical Information of China (English)

    Lei Zhu; Sun-Bok Jo; Shu Ye; Kefayat Ullah; Won-Chun Oh

    2014-01-01

    Nanostructured ZnSe-graphene/TiO2 was synthesized by a hydrothermal-assisted approach. ZnSe-graphene/TiO2 exhibited favorable adsorption of rhodamine B, a wide wavelength absorption range, and efficient charge separation. Reactive oxygen species were generated by the oxidation of 1,5-diphenyl carbazide to 1,5-diphenyl carbazone. The sonocatalytic reaction mechanism was pro-posed. These findings potentially broaden the applications of sonocatalytic technologies.

  6. BIOSORPTION OF CHROMIUM (VI FROM INDUSTRIAL EFFLUENT BY WILD ANDMUTANT TYPE STRAIN OF SACCHAROMYCES CEREVISIAE AND ITS IMMOBILIZED FORM

    Directory of Open Access Journals (Sweden)

    K Selvam, K Arungandhi, B Vishnupriya, T Shanmuga priya and M Yamuna

    2013-01-01

    Full Text Available Biosorption of chromium was studied by wild type Saccharomyces cerevisiae strain, mutant strain, immobilized-wild type and mutant strain. Chromium absorption pattern was observed in all experimental conditions. Hexavalent chromium (VI was analyzed by diphenyl carbazide method, by oxidizing the trivalent chromium (III. The percentage efficiency of wild type S. cerevisiae and its mutant strain, immobilized-wild type and mutant strain were 94.8%, 98.7%, 97.4% and 100% respectively. S. cerevisiae mutant strain and their immobilized form was found to be effective in biosorption of chromium (VI than the wild type forms.

  7. Poly(ethylene glycol)-supported Liquid-phase Parallel Synthesis of Di(aryloxyacetyl)thiosemicarbazides

    Institute of Scientific and Technical Information of China (English)

    Xi Cun WANG; Jun Ke WANG; Zheng LI

    2004-01-01

    An efficient poly(ethylene glycol) (PEG)-supported liquid-phase parallel approach to di(aryloxyacetyl)thiosemicarbazides is described. PEG-bound phenol reacted with chloroacetic acid to afford PEG-bound phenyloxyacetic acid, which was readily converted into corresponding phenyloxyacetyl chloride. Subsequent nucleophilic substitution with ammonium thiocyanate followed by addition of aryloxyacetic acid hydrazides gave PEG-bound di(aryloxyacetyl)thiosemi- carbazides, which were easily cleaved to give the resulting library of 1-aryloxyacetyl-4-(4'- methoxylcarbonylphenyloxyacetyl)thiosemicarbazides in good to high yield and high purity.

  8. Nano-sized silica supported FeCl3 as an efficient heterogeneous catalyst for the synthesis of 1,2,4-triazine derivatives

    Institute of Scientific and Technical Information of China (English)

    Davood Habibi; Somayyeh Vakili

    2015-01-01

    The one‐pot synthesis of a series of 1,2,4‐triazines from the reactions of semicarbazide or thiosemi‐carbazide with various α,β‐dicarbonyl compounds under reflux conditions in a EtOH‐H2O (9:1) mixture as solvent and catalyzed by nano‐sized silica supported FeCl3 (FeCl3@SiO2) was investigat‐ed. The FeCl3 content of the catalyst was measured by atomic absorption to get the adsorption ca‐pacity. The reactions gave high yields of the product and the catalyst was easily separated and re‐used for successive reaction runs without significant loss of activity.

  9. Novel Steroidal (6R)-Spiro-1,3,4-thiadiazoline Derivatives as Anti-bacterial Agents

    Institute of Scientific and Technical Information of China (English)

    Khan Salman A.; Asiri, Abdullah M.

    2012-01-01

    Novel steroidal (6R)-spiro-1,3,4-thiadiazoline derivatives have been synthesized by the cyclization of steroidal thiosemiearbazones. Thiosemicarbazones have been synthesized by the reaction of steroidal ketones with thiosemi- carbazide. All the compounds have been characterized by IR, 1H NMR, mass and elemental analyses. The antibacterial activities of these compounds have been first tested in vitro by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration (MIC) values have been determined with the reference of standard drug amoxicillin. The results showed that steroidal thiadiazoline de- rivatives exhibited better antibacterial activity than the steroidal thiosemicarbazone derivatives. Chloro and acetoxy substituents on the 3β-position of the steroidal thiadiazoline ring increased the anti-bacterial activity. Among all the compounds, compounds 7 and 8 were found better inhibitors as compared to the respective drug amoxicillin.

  10. Groundwater contaminant by hexavalent chromium

    Energy Technology Data Exchange (ETDEWEB)

    Parsons, C. [Univ. of Texas, Austin, TX (United States)

    1995-11-01

    Oxidation of trivalent chromium to hexavalent chromium has been investigated as a function of total manganese in soils as well as various incubation conditions. Chromium and manganese contents were analyzed by atomic absorption (graphite furnace and flame emission respectively) following acid digestion. Total hexavalent chromium generation capacity was determined by addition of 0.001 M CrCL3, incubation, and analysis by s-diphenyl carbazide. Samples were then leached with CaSO{sub 4} and MgSO{sub 4} and incubated in various environments (oven, freeze-drier, field moist, ultrafreeze) to test for geogenic generation of Cr(IV). The degree of geogenic generation of hexavalent chromium was compared with total Mn and Cr content as well as hexavalent generational capacity.

  11. Novel “turn on” fluorescent sensors based on anthracene and carbazone units for Cu (II) ion in CH{sub 3}CN–H{sub 2}O

    Energy Technology Data Exchange (ETDEWEB)

    Erdemir, Serkan, E-mail: serdemir82@gmail.com; Malkondu, Sait

    2015-02-15

    Two novel anthracene-based receptors containing Schiff base and urea groups (AOC and ATC) were synthesized in one step and full characterized. The optical properties of receptors AOC and ATC towards metal ions were investigated by UV–visible and fluorescence spectroscopy. It was found that both receptors AOC and ATC show highly selectivity towards Cu{sup 2+} over other 17 metal ions in CH{sub 3}CN–H{sub 2}O (9/1, v/v). - Highlights: • Novel fluorescent sensors based on anthracene and carbazide AOC and ATC were synthesized. • The optical properties of AOC and ATC were observed by UV–visible and fluorescence spectroscopy. • AOC and ATC showed highly selective and sensitive to Cu{sup 2+} over other 17 metal ions.

  12. Confirmation of hydroxyl radicals (•OH) generated in the presence of TiO2 supported on AC under microwave irradiation.

    Science.gov (United States)

    Zhang, Zhaohong; Yu, Fengyang; Huang, Lirong; Jiatieli, Jianaerguli; Li, Yuanyuan; Song, Lijun; Yu, Ning; Dionysiou, Dionysios D

    2014-08-15

    In order to study the degradation mechanism of technology of microwave (MW) combined with TiO2 supported on activated carbon (TiO2/AC), the reactive oxygen species (ROS) was explored through oxidation of 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). Furthermore, 2,6-di-tert-butyl-4-methylphenol (BHT), Mannitol (MT) and Vitamin C (VC) were used as radical scavengers to confirm the generation of the hydroxyl radicals ((•)OH). In addition, the influence of some parameters such as TiO2 mass ratio content, irradiation time, material dose, DPCI concentration and MW power on the determination of (•)OH were examined. The results showed that the (•)OH could be generated under MW combined with loaded TiO2/AC. Also, anatase TiO2/AC can generate more (•)OH radicals than rutile TiO2/AC under MW irradiation. This work would provide new mechanistic insights on the enhanced degradation effect of organic pollutants in water using the supported TiO2/AC coupled with MW technology.

  13. Čudesna molekula benzotriazol

    Directory of Open Access Journals (Sweden)

    Zorc, B.

    2007-03-01

    Full Text Available In this paper, a review of reactions with benzotriazole as synthetic auxiliary is given. In contrast to most other azoles, benzotriazole reacts with phosgene in molar ratio 1:1 yielding carboxylic acid chloride (BtcCl, 1, which readily reacts with nucleophiles giving reactive compounds. These products can be easily transformed into carbamates, ureas, semicarbazides, carbazides, sulfonylureas, sulfonylcarbazides, nitroalkanic acid esters, etc. In addition, benzotriazole was used in the synthesis of various heterocyclic compounds: benzoxazine, kinazoline, triazinetrione, hydantoin and oxadiazine derivatives. The reaction of chloride 1 with amino acids enabled the use of benzotriazole in peptide chemistry, with triple role of benzotriazolecarbonyl group as N-protecting, N-activating, and both N-protecting/C-activating group. N-(1-benzotriazolecarbonyl-amino acids 25 are starting compounds in the synthesis of various amino acid, di- and tripeptide derivatives, hydantoic acids and hydroxyureas.Benzotriazole was also applied in the preparation of polymer-drug and thiomer-drug conjugates, polymeric prodrugs with drugs covalently bound to the polymeric carriers. Such macromolecular prodrugs may offer many advantages compared to other drug delivery systems such as increased drug solubility, prolonged drug release, increased stability. It is also possible to accumulate the drug at the site of the pathological process and to minimize its toxicity. In this paper, the binding of drugs from various therapeutic groups (mostly nonsteroidal, anti-inflammatory drugs to polymersof polyaspartamide type by the benzotriazolide method is described.

  14. IMPACT OF BLEACHING STRESS ON THE FUNCTION OF THE OXYGEN EVOLVING COMPLEX OF ZOOXANTHELLAE FROM SCLERACTINIAN CORALS(1).

    Science.gov (United States)

    Hill, Ross; Ralph, Peter J

    2008-04-01

    Global climate change is leading to the rise of ocean temperatures and is triggering mass coral bleaching events on reefs around the world. The expulsion of the symbiotic dinoflagellate algae is believed to occur as a result of damage to the photosynthetic apparatus of these symbionts, although the specific site of initial impact is yet to be conclusively resolved. Here, the sensitivity of the oxygen evolving complex (OEC) to bleaching stress was studied as well as its natural variation between seasons. The artificial electron donor, diphenyl carbazide (DPC), was added to cultured, freshly isolated and expelled (bleaching treatments only) zooxanthellae suspensions. Chl a fluorescence and oxygen production measurements showed that upon addition of DPC, no restoration of diminished photochemical efficiency occurred under control or bleaching conditions. This result was consistent between 12 h and 5 d bleaching treatments on Pocilloporadamicornis, indicating that the OEC is not the primary site of damage, and that zooxanthellae expulsion from the host is a nonselective process with respect to the functioning of the OEC. Further experiments measuring fast induction curves (FICs) revealed that in both summer and winter, the temperature when OEC function was lost occurred between 7°C and 14°C above the sea surface temperature. FIC and oxygen production measurements of P. damicornis during exposure to bleaching stress demonstrated that the thermotolerance of the OEC increased above the temperature of the bleaching treatment over a 4 h period. This finding indicates that the OEC has the capacity to acclimate between seasons and remains functional at temperatures well above bleaching thresholds. PMID:27041186

  15. Confirmation of hydroxyl radicals ({sup •} OH) generated in the presence of TiO{sub 2} supported on AC under microwave irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Zhaohong, E-mail: lnuhjhx@163.com [School of Environmental Science, Liaoning University, Shenyang 110036 (China); Yu, Fengyang; Huang, Lirong; Jiatieli, Jianaerguli; Li, Yuanyuan; Song, Lijun [School of Environmental Science, Liaoning University, Shenyang 110036 (China); Yu, Ning [Experiment Center of Environmental Monitoring of Liaoning Province, Shenyang 110161 (China); Dionysiou, Dionysios D., E-mail: dionysios.d.dionysiou@uc.edu [Environmental Engineering and Science Program, University of Cincinnati, Cincinnati, OH 45221-0012 (United States)

    2014-08-15

    Graphical abstract: - Highlights: • Generation of {sup •} OH in MW integrated with loaded TiO{sub 2}/AC system was confirmed. • Confirmation of {sup •} OH was conducted using radical scavenger such as BHT, MT and VC. • More {sup •} OH was formed using anatase TiO{sub 2}/AC than rutile TiO{sub 2}/AC under MW irradiation. • Effect of mass ratio, irradiation time, catalyst dose and DPCI on {sup •} OH was studied. - Abstract: In order to study the degradation mechanism of technology of microwave (MW) combined with TiO{sub 2} supported on activated carbon (TiO{sub 2}/AC), the reactive oxygen species (ROS) was explored through oxidation of 1,5-diphenyl carbazide (DPCI) to 1,5-diphenyl carbazone (DPCO). Furthermore, 2,6-di-tert-butyl-4-methylphenol (BHT), Mannitol (MT) and Vitamin C (VC) were used as radical scavengers to confirm the generation of the hydroxyl radicals ({sup •} OH). In addition, the influence of some parameters such as TiO{sub 2} mass ratio content, irradiation time, material dose, DPCI concentration and MW power on the determination of {sup •} OH were examined. The results showed that the {sup •} OH could be generated under MW combined with loaded TiO{sub 2}/AC. Also, anatase TiO{sub 2}/AC can generate more {sup •} OH radicals than rutile TiO{sub 2}/AC under MW irradiation. This work would provide new mechanistic insights on the enhanced degradation effect of organic pollutants in water using the supported TiO{sub 2}/AC coupled with MW technology.

  16. A novel solidified floating organic drop microextraction method for preconcentration and determination of copper ions by flow injection flame atomic absorption spectrometry.

    Science.gov (United States)

    Sahin, Ciğdem Arpa; Tokgöz, Ilknur

    2010-05-14

    A rapid, simple and cost effective solidified floating organic drop microextraction (SFODME) and flow injection flame atomic absorption spectrometric determination (FI-FAAS) method for copper was developed. In this method, a free microdrop of 1-undecanol containing 1,5-diphenyl carbazide (DPC) as the complexing agent was transferred to the surface of an aqueous sample including Cu(II) ions, while being agitated by a stirring bar in the bulk of the solution. Under the proper stirring conditions, the suspended microdrop can remain at the top-center position of the aqueous sample. After the completion of the extraction, the sample vial was cooled by placing it in a refrigerator for 10min. The solidified microdrop was then transferred into a conical vial, where it melted immediately and diluted to 300microL with ethanol. Finally, copper ions in 200microL of diluted solution were determined by FI-FAAS. Several factors affecting the microextraction efficiency, such as type of extraction solvent, pH, complexing agent concentration, extraction time, stirring rate, sample volume and temperature were investigated and optimized. Under optimized conditions for 100mL of solution, the preconcentration factor was 333 and the enrichment factor was 324. The limit of detection (3s) was 0.4ngmL(-1), the limit of quantification (10s) was 1.1ngmL(-1) and the relative standard deviation (RSD) for 10 replicate measurements of 10ngmL(-1) copper was 0.9%. The proposed method was successfully applied to the determination of copper in different water samples. PMID:20441870

  17. Determination Method of Chromium ( Ⅵ ) Released From Food Packaging Materials of Ceramic and Glass%陶瓷和玻璃食品包装铬溶出量测定方法

    Institute of Scientific and Technical Information of China (English)

    黄梅

    2011-01-01

    目的 建立陶瓷、玻璃食品包装中铬(Ⅵ)溶出量的测定方法.方法以4%乙酸溶液为萃取剂,在适合的酸性条件下,样品中溶出铬(Ⅵ)与二苯碳酰二肼显色生成紫色配合物,分光光度法测定.结果方法检出限为0.01 mg/L,线性范围为0.01~1.00 mg/L,R2 =0.999 9,平均回收率在95.1%~99.1%.结论该方法快速简便、灵敏准确,可满足食品包装中微量溶出铬(Ⅵ)的测定.%Objective To establish the method for determination of chromium ( Ⅳ) in food packaging materials of ceramic and glass. Methods The extracting agent was 4% acetic acid solution, under acidic condition, the dissolved chromium (Ⅳ) from food ceramic and glass packaging materials reacted with Diphenyl Carbazide (DPC) and formed purple complex, which was determined by spectrophotometry. Results The detection limit was 0. 01mg/L, with the linear range of 0. 01 - 1. 00 mg/L, the correlation coefficient was 0. 9999, and recoveries ranged from 95. 1% to 99. 1%. Conclusion The method is simple, rapid, sensitive and accurate, it can be directly applied to detect trace dissolved chromium (Ⅳ) in food packaging materials.

  18. Low temperature reduction of hexavalent chromium by a microbial enrichment consortium and a novel strain of Arthrobacter aurescens

    Directory of Open Access Journals (Sweden)

    Thompson Vicki S

    2006-01-01

    Full Text Available Abstract Background Chromium is a transition metal most commonly found in the environment in its trivalent [Cr(III] and hexavalent [Cr(VI] forms. The EPA maximum total chromium contaminant level for drinking water is 0.1 mg/l (0.1 ppm. Many water sources, especially underground sources, are at low temperatures (less than or equal to 15 Centigrade year round. It is important to evaluate the possibility of microbial remediation of Cr(VI contamination using microorganisms adapted to these low temperatures (psychrophiles. Results Core samples obtained from a Cr(VI contaminated aquifer at the Hanford facility in Washington were enriched in Vogel Bonner medium at 10 Centigrade with 0, 25, 50, 100, 200, 400 and 1000 mg/l Cr(VI. The extent of Cr(VI reduction was evaluated using the diphenyl carbazide assay. Resistance to Cr(VI up to and including 1000 mg/l Cr(VI was observed in the consortium experiments. Reduction was slow or not observed at and above 100 mg/l Cr(VI using the enrichment consortium. Average time to complete reduction of Cr(VI in the 30 and 60 mg/l Cr(VI cultures of the consortium was 8 and 17 days, respectively at 10 Centigrade. Lyophilized consortium cells did not demonstrate adsorption of Cr(VI over a 24 hour period. Successful isolation of a Cr(VI reducing organism (designated P4 from the consortium was confirmed by 16S rDNA amplification and sequencing. Average time to complete reduction of Cr(VI at 10 Centigrade in the 25 and 50 mg/l Cr(VI cultures of the isolate P4 was 3 and 5 days, respectively. The 16S rDNA sequence from isolate P4 identified this organism as a strain of Arthrobacter aurescens, a species that has not previously been shown to be capable of low temperature Cr(VI reduction. Conclusion A. aurescens, indigenous to the subsurface, has the potential to be a predominant metal reducer in enhanced, in situ subsurface bioremediation efforts involving Cr(VI and possibly other heavy metals and radionuclides.

  19. Studies of nanosecond pulsed power for modifications of biomaterials and nanomaterials (SWCNT)

    Science.gov (United States)

    Chen, Meng-Tse

    This work investigates the modification of biological materials through the applications of modern nanosecond pulsed power, along with other forms of nanotechnologies. The work was initially envisaged as a study of the effect of intense nanosecond pulsed electric fields on cancer cells. As the work progressed, the studies suggested incorporation of additional technologies, in particular, cold plasmas, and carbon nanotubes. The reasons for these are discussed below, however, they were largely suggested by the systems that we were studying, and resulted in new and potentially important medical therapies. Using nanosecond cold plasmas powered with nanosecond pulses, collaboration with endodontists and biofilm experts demonstrated a killing effect on biofilms deep within root canals, suggesting a fundamentally new approach to an ongoing problem of root canal sterilization. This work derived from the application of nanosecond pulsed power, resulting in effective biofilm disinfection, without excessive heating, and is being investigated for additional dental and other medical applications. In the second area, collaboration with medical and nanotube experts, studies of gliomamultiforme (GBM) led to the incorporation of functionalized carbon nanotubes. Single-walled carbon nanotube-fluorescein carbazide (SWCNT-FC) conjugates demonstrated that the entry mechanism of the single-walled carbon nanotubes (SWCNTs) was through an energy-dependent endocytotic pathway. Finally, a monotonic pH sensitivity of the intracellular fluorescence emission of SWCNT-FC conjugates in human ovarian cancer cells suggests these conjugates may serve as intracellular pH sensors. Light-stimulated intracellular hydrolysis of the amide linkage and localized intracellular pH changes are proposed as mechanisms. The use of SWCNTs for cancer therapy of gliomas, resulting in hyperthermia effect after 808 nm infrared radiations, absorbed specifically by SWCNTs but not by biological tissue. Heat was only

  20. Chromium(III, VI) speciation analysis with preconcentration on a maleic acid-functionalized XAD sorbent

    International Nuclear Information System (INIS)

    Chromium may exist in environmental waters as Cr(III) and Cr(IV), the latter being the toxic and carcinogenic form. Since atomic absorption spectrometry (AAS) and inductively coupled plasma atomic emission spectrometry can only yield information on total Cr concentration, a polymer resin bearing O,O-donor chelating groups such as the maleic acid-functionalized XAD-(CO)CH-CH-COOH resin was synthesized to selectively retain Cr(III) at pH 4.0-5.5. The dynamic breakthrough capacity of the resin for Cr(III) at pH 5.0 was 7.52 mg g-1, and the preconcentration factor extended to 250-300. Chromium(III) in the presence of 250-fold Cr(VI)--which was not retained--could be effectively preconcentrated on the NH4+-form of the resin and determined by AAS or diphenylcarbazide (DPC) spectrophotometry. When Cr(VI) was reduced to Cr(III) with Na2SO3 solution brought to pH 1 by the addition of 1 M H2SO4, and preconcentrated on the resin, total Cr could be determined. The developed method was validated with a blended coal sample CRM-1632. Since the adsorption behavior as a function of pH of possible interferent metal ions, e.g. Ni(II), Co(II), Cu(II), Cd(II), Zn(II), Pb(II) and Fe(III), was similar to that of Cr(III), selective elution of Cr(III) from the resin was realized using a mixture of 1 wt.% H2O2+1 M NH3. The eluate containing Cr as chromate could be directly analyzed by diphenyl carbazide spectrophotometry without any adverse effect from the common interferents of this method, i.e. Fe(III), Cu(II) Hg(II), VO3-, MoO42- and WO42-. Various synthetic waste solutions typical of electroplating bath effluents containing Cr, Cu, Ni, Zn, Na, Ca, cyanide (and chemical oxidation demand (COD), achieved by glucose addition) were subjected to pretreatment procedures such as hypochlorite oxidation (of cyanide) and catalytic oxidation (of COD) with peroxodisulfate. Chromium determination gave satisfactory results. The combined column preconcentration--selective elution

  1. Improved synthesis of dipyridyl thioselenosemicarbazones%双吡啶酮缩氨基硒脲的合成工艺改进

    Institute of Scientific and Technical Information of China (English)

    邢晓东; 钟武

    2016-01-01

    Objective To improve the synthesis process of N-allyl-2-(di(pyridin-2-yl)methylene)hydrazinecarboseleno⁃amide(4)and 2-(di(pyridin-2-yl)methylene)-N,N-dimethylhydrazinecarboselenoamide(8). Methods 4-allyl-3-thiosemicarbazide (1)was the starting material,which reacted with methyl iodide,sodium hydrogen selenide to obtain intermediate 4-allyl-3-selenosemi⁃carbazide(3). Compound(3)reacted with di-2-pyridyl ketone to obtain the target compound 4. 4,4-Dimethyl-3-thiosemicarbazide was the starting materials,which reacted with di-2-pyridyl ketone to obtain intermediate dipyridyl thiosemicarbazone(6). Compound 6 re⁃acted with methyl iodide,sodium hydrogen selenide to obtain the target compound 8. We optimized the reaction conditions of each step. Results We synthesized the target compound 4 and 8 according to the respective synthetic route,the structure of the target com⁃pounds and the intermediates were confirmed by 1H NMR and MS. Conclusion The improved processes are easy to operate,cost-saving and suitable for large scale preparation.%目的:改进双(2-吡啶)酮缩-4-烯丙基-3-氨基硒脲(4)和双(2-吡啶)酮缩-4,4-二甲基-3-氨基硒脲(8)的合成工艺。方法以4-烯丙基-3-氨基硫脲为起始原料,经碘甲烷甲基化,硒氢化钠取代,最后与双(2-吡啶)酮脱水缩合制得终产物4;以4,4-二甲基-3-氨基硫脲为起始原料,与双(2-吡啶)酮脱水缩合,再经碘甲烷甲基化,硒氢化钠取代,最终制得终产物8;并优化各步反应条件。结果按照相应的合成路线有效制备了目标化合物4和8,目标化合物与中间体的结构均经1H NMR、MS谱确认。结论优化后的工艺路线具有成本低、操作简便、适合大量制备等优点。