Sample records for 1,2,4,5-tetramethylbenzene

  1. The disposition and metabolism of durene (1,2,4,5-tetramethylbenzene) in rats

    Ligocka, D.; Sapota, A.; Rydzynski, K. [Nofer' s Inst. of Occupational Medicine, Lodz (Poland)


    The organ and tissue distribution, excretion and metabolism of [{sup 3}H]1,2,4,5-tetramethylbenzene ([{sup 3}H]durene) in male Wistar albino rats were investigated following a single i.p. administration (40 mg/kg) and within 9 days after five daily repeated administrations. Urine proved to be the main route of tritium excretion. Within the first 24 h after a single administration 69% of the radioactivity was excreted in the urine and only 9% in the feces. The highest level of tritium binding was found in the fat tissue, liver, kidneys and adrenal glands. The accumulation of tritium in the plasma proceeded with a kinetic constant of 0.49 h{sup -1}, whereas the half-life of radioactivity decayamounted to about 6.3 h. In erythrocytes, the tritium level was found to be about three times lower than in blood plasma. The total amount eliminated during the 9 days following repeated administration was about 94% of the five doses given. The highest level of tritium was found in fat tissue and adrenal glands, followed by the liver, kidneys, sciatic nerve and muscle. A gradual decline in tritium levels was observed during the following 4 days in most tissues to reach about 2% of the dose given. The main urinary metabolites resulting from the administration of durene were 2,4,5-trimethylbenzyl alcohol (about 22%), 4,5-dimethyl-1,2-benzdialdehyde (about 19%), 2,4,5-trimethylbenzaldehyde (about 19%) and 2,4,5-trimethylbenzoic acid (about 16%). The oxygen-containing metabolites accounted for almost 80%, whereas sulphur-containing metabolites accounted for approximately 10% of the products of biotransformation. In conclusion, most of the durene administered has a relatively rapid turnover rate, with minor levels retained in the tissues for longer time periods. (orig.)

  2. A method for removing aromatic hydrocarbons from liquid n-paraffins

    Gayle, A.A.; Pavlyuk, N.F.; Proskuryakov, V.A.; Semenov, L.V.; Zakhrov, A.P.


    In the known method for removing aromatic hydrocarbons from liquid n-paraffins through liquid extraction by a selective solvent, in order to increase the output of the paraffins methoxyacetonitrile (I) is used as the selective solvent. The advantages of the extraction process using I are high output and quality of the purified paraffins and the possibility of using series produced extractors of medium effectiveness. The high selectivity of I relative to aromatic hydrocarbons, unlike low selective acetone in the known method and its high density (1.032) as compared with acetone (0.790) provide for effective mass exchange in industrial performance of the process. The regeneration of I from the extraction phase may be accomplished through rectification. In an example of single stage isolation of mixtures of n-tetradecane with 1,2,4,5-tetramethylbenzene and 1-methylnaphthaline (a temperature of 30 degrees, a ratio of solvent to raw material of 3, an aromatic hydrocarbon content in the mixture of 1.0 percent) showed the following.

  3. Selective Synthesis of 2,6-Dimethylnaphthalene by Transalkylation in the Presence of Acid Ionic Liquids[Cnmim]Cl-AlCl3

    WU Guang; WU Wei; XIAO Lin-fei; LIU Dan


    A highly selective synthesis of 2,6-dimethylnaphthanlene(2,6-DMN)by transalkylation between 2-methylnaphthanlene(2-MN)and 1,2,4,5-tetramethylbenzene(TeMB)was performed with 1-alkyl-3-methylimidazolium aluminum chloride([Cnmim]Cl-AlCl3)ionic liquids(ILs)as catalysts.The influences of the alkyl group as the organic cation,the acidic strength of[C4mim]Cl-AlCl3 ILs as well as the reaction conditions on the catalytic performance were investigated.[C4mim]Cl-AlCl3 ILs[x(AlCl3)=71%]exhibited high activity and selectivity toward 2,6-DMN.The selectivity to 2,6-DMN and the 2,6-DMN/2,7-DMN ratio reached up to 68.2% and 3.7∶1,respectively.The UV-Vis spectrum of TeMB treated by different ILs shows that the protonated degree of TeMB dependeds on the acidity strength of ILs,which has a significant impact on the reaction results.The high protonated degree of TeMB is advantageous to enhancing the conversion of transalkylation and the large stereo-hindrance effect of TeMB is favorable to improving the selecivity to 2,6-DMN.

  4. Effect of nuclear spin on chemical reactions and internal molecular rotation

    Sterna, L.L.


    Part I of this dissertation is a study of the magnetic isotope effect, and results are presented for the separation of /sup 13/C and /sup 12/C isotopes. Two models are included in the theoretical treatment of the effect. In the first model the spin states evolve quantum mechanically, and geminate recombination is calculated by numerically integrating the collision probability times the probability the radical pair is in a singlet state. In the second model the intersystem crossing is treated via first-order rate constants which are average values of the hyperfine couplings. Using these rate constants and hydrodynamic diffusion equations, an analytical solution, which accounts for all collisions, is obtained for the geminate recombination. The two reactions studied are photolysis of benzophenone and toluene and the photolytic decomposition of dibenzylketone (1,3-diphenyl-2-propanone). No magnetic isotope effect was observed in the benzophenone reaction. /sup 13/C enrichment was observed for the dibenzylketone reaction, and this enrichment was substantially enhanced at intermediate viscosities and low temperatures. Part II of this dissertation is a presentation of theory and results for the use of Zeeman spin-lattice relaxation as a probe of methyl group rotation in the solid state. Experimental results are presented for the time and angular dependences of rotational polarization, the methyl group magnetic moment, and methyl-methyl steric interactions. The compounds studied are 2,6-dimethylphenol, methyl iodide, 1,4,5,8-tetramethylanthracene, 1,4,5,8-tetramethylnaphthalene, 1,2,4,5-tetramethylbenzene, and 2,3-dimethylmaleicanhydride.

  5. Advances in coke formation rule of heavy oil at the molecular level%分子水平重油生焦规律研究进展

    李中亚; 申海平; 范启明


    At the molecular level, advances of coke formation rule of heavy oil were reviewed.The relation between four components of heavy oil and coke formation was induced,so was the research in the coke formation of heavy oil model compounds.For group constituents of heavy oil,researches show that proper amounts of saturates lead to high-quality coke;the quality of coke gets worse with more rings;resins and asphaltenes coke easily and the quality of coke is bad;heteroatoms lead to bad coke,but hazard extent of heteroatoms is different.For heavy oil model compounds,researches show that thermal condensation of toluene is hard to react;from naphthalene to pyrene,the condensation difficulty becomes lower and lower;because of side chains,the quality of dimethylnaphthalene coke is worse than that of naphthalene;because of its special spatial configuration,1,2,4,5-tetramethylbenzene cokes easily and quality of the coke is pretty good;the worse the quality of heteroatom model compound coke,the worse the quality of aromatics with that kind of heteroatom model compounds.With the development of the ultra high resolution mass spectrometry technology,there are more possibilities that aromatics thermal condensation reaction mechanism will be explored further.%阐述了重油缩合生焦规律分子水平的研究进展,主要从重油中四组分的分子组成与生焦的关系以及重油模型化合物生焦的研究两方面进行了概述。研究表明,对于重油各族组分来说:适量的饱和分有助于提升生焦质量;芳香分环数越多生焦越明显,生焦质量越差;中、重胶质和沥青质易生焦,生焦质量差;杂原子会降低生焦质量,但各个杂原子的危害程度不同。而对于各个重油模型化合物来说:甲苯极难发生热缩合反应;萘、菲、蒽、芘的热缩合反应难度逐渐降低;二甲基萘由于侧链的作用,生焦质量比萘要差;1,2,4,5-四甲基苯由于其特殊的空间构型较易