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31.
R. V. Dmitriev O. V. Bragin T. V. Vasina A. A. Klyuchanskii R. I. Sokolova I. G. Rassamakhina Kh. M. Minachev 《Russian Chemical Bulletin》1990,39(8):1757-1758
Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 8, pp. 1931–1932, August, 1990. 相似文献
32.
Savinova O. S. Zorov I. N. Vasina D. V. Sinitsyn A. P. Fedorova T. V. 《Moscow University Chemistry Bulletin》2019,74(4):173-179
Moscow University Chemistry Bulletin - Laccases (EC 1.10.3.2) are multicopper polyphenol oxidases found in various organisms, in particular, in fungi. Fungal laccases are encoded by multigene... 相似文献
33.
丝瓜中维生素C含量的测定 总被引:1,自引:0,他引:1
为建立丝瓜中维生素C含量直接测定的新方法,以10%盐酸溶液为溶剂,采用紫外分光光度法测定其含量。结果表明,维生素C在0~10 mg/L质量浓度范围内与吸光度呈良好的线性关系,回归方程为:y=0.047 46ρ+0.001 09,r=0.999 7。检出限为0.023μg/mL,加标回收率在90.6%~99.0%之间。该法操作简单,结果准确,应用于维生素C含量的测定,结果准确,令人满意,可作为控制维生素C质量的方法。 相似文献
34.
Vladislav A. Ksenofontov Tamara V. Vasina Yuri E. Zubarev Leonid M. Kustov 《Reaction Kinetics and Catalysis Letters》2003,80(2):329-335
Cyclohexane and methylcyclopentane isomerization were carried out under mild conditions using an ionic liquid consisting of
n-butylpyridinium chloride and aluminum chloride as catalyst. The ionic liquid showed reasonably high catalytic activity in
both reactions with a selectivity to corresponding products of 100%. In the case of cyclohexane isomerization, the thermodynamic
equilibrium methylcyclopentane ⇌cyclohexane was almost achieved. For the reaction of cyclohexane isomerization, the kinetic
study was performed, and the rate constants and the activation energy of the process were determined.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
35.
A new withasteroid — vamonolide — has been isolated from the epigeal part ofPhysalis angulata L. (Solanaceae). On the basis of spectral characteristics, its structure has been established as 5α,14α-dihydroxyl-l-oxo-6α,7α-epoxy-20R,22R-with-2-enolide. 相似文献
36.
V. P. Sitnik N. V. Nekrasov T. V. Vasina V. I. Yakerson O. V. Bragin 《Russian Chemical Bulletin》1990,39(4):641-646
The kinetics of transformations of propane and propylene on pentasils modified with zinc, Zn/HTsVM, and the H form of zeolite were investigated. Quantitative data were obtained which revealed significant differences for HTsVM and Zn-containing catalysts in the selectivity of transformations of propane with different degrees of its conversion. The promoting effect of Zn in the Zn/HTsVM system not only on the stage of dehydrogenation of propane into propylene, but also on subsequent transformations of propylene into aromatic hydrocarbons, was demonstrated. The absence of internal diffusion inhibition of the reaction in the conditions studied was demonstrated experimentally. It was shown that aromatization of propane takes place in the kinetic region.For previous communication, see [1].Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 4, pp. 727–733, April, 1990. 相似文献
37.
A. V. Ivanov E. G. Khelkovskaya-Sergeeva T. V. Vasina O. V. Masloboishchikova L. M. Kustov P. Zeuthen 《Russian Chemical Bulletin》1999,48(7):1266-1269
The catalytic activity of superacidic systems based on SO4/ZrO2 and modified by IV Period metals in isomerization ofn-butane was studied. At low temperatures of the reaction, the introduction of Fe3+, Sc3+, Co2+, or Zn2+ ions (1%) increases the yield of isobutane by 1.5 times due to the activation ofn-butane on the sites created by the promoting ions. The addition of Cr3+, V4+, or Mn2+ (1%) decreases the catalytic activity because of a decrease in the catalyst acidity, most likely, due to the reduction of
surface sulfur species. The influence of the nature of the support and surface additives of SiO2, TiO2, and ZrO2 on the activity and selectivity of the catalytic system inn-butane isomerization was studied.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7 pp. 1276–1280, July, 1999 相似文献
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Conclusions 3,3,6-Trimethylcycloheptanone was synthesized for the first time and its properties were described. 相似文献