Synthesis and structures of triphenylantimony oximates

The reactions of triphenylantimony or trimethylantimony with tert-butyl hydroperoxide in the presence of acetone oxime, acetophenone oxime, cyclohexanone oxime, or benzaldehyde oxime afforded monomeric triorganoantimony oximates Ph₃Sb(ON=CMe₂)₂, Ph₃Sb(ON=CMePh)₂, Ph₃Sb[ON=C(CH₂)₅]₂, Ph₃Sb(ON=CHPh)₂, and Me₃Sb(ON=CMe₂)₂ in 87—96% yields. X-ray diffraction analysis demonstrated that Ph₃Sb(ON=CMe₂)₂ and Ph₃Sb(ON=CHPh)₂ have trigonal-bipyramidal structures. An analogous reaction with dimethylglyoxime gave rise to polymeric triphenylantimony dioximate in 96% yield. The reaction with butane-2,3-dione monoxime yielded chelate cyclic bis(triphenylantimony) oxides.     

Structure of (Z)-(5R)-methyl-2-(4-phenylbenzylidene)cyclohexanone as chiral component of liquid-crystalline systems

The spatial structure of (Z)-(5R)-methyl-2-(4-phenylbenzylidene)cyclohexanone prepared by photochemical isomerization of the E-isomer was studied by analyzing the magnitudes and temperature dependence of the proton spin-spin coupling constants obtained by ¹H NMR spectroscopy and the results of molecular modeling using semiempirical quantum chemical AM1 and PM3 methods and the density functional theory (DFT). Comparison of the results obtained for the Z-and E-isomers shows that in both cases the conformational equilibrium for both isomers is characterized by significant preference of the chair conformer having an equatorial methyl group, namely, − ΔH (chair a ⇌ chair e) = 1.98–2.12 and 1.36–1.54 kcal mole⁻¹ for the Z-and E-isomers, respectively. Distinctions in the non-planarity of the enone fragment and cyclohexanone ring in the Z-and E-isomers under study following from the results of mathematical modeling were confirmed by the experimental values of the geminal spin-spin coupling constants of protons of the methylene groups in α,α ′-positions with respect to the enone group. Quantum chemical calculations of the Z-isomer revealed the existence of intramolecular hydrogen bond between the carbonyl oxygen and the nearest aromatic proton in ortho-position of the benzene ring. Possible reasons for different helical twisting power of (Z)-(5R)-methyl-2-(4-phenylbenzylidene)cyclohexanone and the E-and Z-arylidene derivatives of 1R, 4R-isomenthone in the mesophase are discussed based on the results of molecular structure studies for these compounds. In the text below the unsaturated ketones under study will be called “arylidene cyclohexanone derivatives” for convenience of comparing the characteristics of methylcyclohexanone and isomenthone derivatives. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 962–972, June, 2006.     

Cyclohexanone preparation via the gas phase carboxidation of cyclohexene by nitrous oxide

Summary Nitrous oxide is known to provide non-catalytic liquid phase oxidation of alkenes to carbonyl compounds (the carboxidation reaction). This paper shows that carboxidation of cyclohexene can be successfully conducted in the gas phase, too. The gas phase carboxidation is a second order reaction proceeding at 325-450°C under 3-16 bar pressure with an activation energy of 26 kcal/mol. The reaction mechanism does not involve free radical steps and leads to cyclohexanone as a main product.     

N-(1-环己烯基)吗啉制备实验的改进

实验教材上以吗啉和环己酮为原料,对甲基苯磺酸为催化剂,甲苯作带水剂,通过缩合反应制备N-(1-环己烯基)吗啉。实验存在着耗时长、易造成实验室内有毒气体甲苯含量高、产品色泽深和收率低(小于60%)等不足。依据实验的目的、原理、内容不变的原则,采用 n/n为1.6,预缩合反应1 h后加入共沸剂,反应加入对苯二酚,环己烷作共沸剂,分馏提纯产品等措施进行改进实验。改进后的实验,反应时间缩短了1 h、室内空气环境友好、产品近乎无色、收率可达80%以上。环己酮吗啉     

2－（1，3－亚丙二硫基）亚甲基环己酮的晶体结构

报导了标题化合物Ｃ_（１０）Ｈ_（１４）ＯＳ_２（Ｍ_ｒ＝２１４．３５）的晶体结构，该晶体属正交晶系，空间群为Ｐ２_１２_１２_１，晶胞参数为ａ＝６．４４３（３），ｂ＝８．９８０（４），ｃ＝１８．２１３（７）；Ｖ＝１０５３．８（６）３；Ｚ＝４，Ｄ_ｘ＝１．３５ｇ／ｃｍ~３，Ｆ（０００）＝４５５，μ＝４．５ｃｍ~（－１）（ＭｏＫａ）。最终偏离因子Ｒ＝０．０３３，Ｒ_ｗ＝０．０３４。分子中的两支Ｃ_（ｓｐ）２－Ｓ键键长近于相等，分别为１．７６１（３）和１．７６９（３），Ｃ（１）－Ｃ（５）键长为１．３６１（４）。     

Analysis of femtosecond laser ionization/dissociation of polyatomic molecule C6H10O from one-colour pump-probe measurement

This paper reports that a one-colour fs pump-probe measurement has been carried out for studying photoionization/photodissociation of cyclohexanone (C6H10O) in intense laser field. Two of the fragments from cyclohexanone, C2H3+ and C3H3+ , are studied under 800 nm laser pump-probe and the results obtained show similar time evolutions. It proposes a feasible model for analysing the experimental observations of the one-colour fs pump-probe measurement. The results demonstrate that as an intermediate product, the excited molecular parent ions play a very important role in photionization/photodissociation processes in intense laser field.     

活性炭负载磷钨酸催化合成环己酮缩乙二醇

研究了活性炭负载磷钨酸催化合成环己酮缩乙二醇的反应 ,考察了催化剂负载量、反应时间、酮醇物质的量比、反应温度等因素对缩酮反应的影响 .结果表明 ,活性炭负载磷钨酸是合成缩酮的良好催化剂 ,在优化条件下 ,缩酮产率达 94.8% ,催化剂可重复使用     

高活性MgO/SnO2复合金属氧化物催化剂的合成及在双氧水选择氧化环己酮制ε-己内酯反应中的应用

通过共沉淀法制备了一系列Mg基复合金属氧化物,采用X射线衍射（XRD）、热重（TG）以及N2 吸附（BET）等表征手段对催化剂的结构进行了表征,并研究了其对双氧水体系中环己酮Baeyer-Villiger氧化制己内酯的催化反应性能,考察了不同组成和配比的催化剂以及反应条件对催化活性的影响。结果表明,在以H2O2水溶液为氧化剂,苯甲腈和二氧六环混合溶液为溶剂时,复合金属氧化物MgO/SnO2体现出比MgO/La2O3、MgO/TiO2、MgO/ZnO、MgO/ZrO2等催化剂更优异的催化性能。同时发现金属摩尔比为7:3,焙烧温度为600℃ 的MgO/SnO2催化剂在优选反应条件下可使环己酮的最高转化率达90.5%,己内酯的选择性达到100%。     

Simple and Efficient Procedure for Highly Diastereoselective Synthesis of trans- 1,1-Disubstituted-2,6-diarylcyclohexane-4-ones

A simple and efficient method has been developed for highly diastcreoselective synthesis of trans-1,1-disubstituted-2,6-diarylcyclohexane-4-ones from dibenzalacetone and malononitril with trans-1,2-diaminocyclohexane as catalyst. The substrate 1,5-diaryl-1,4-pentadien-3-ones and active methylene compounds proceeded to give the products with good to excellent yield within a short time.     

电喷雾萃取电离-三重四极杆质谱快速检测PVC医疗器械中残留环己酮的方法研究

环己酮是一种广泛使用在PVC医疗器械生产中的粘接剂, 残留的环己酮会通过输液或介入治疗等过程进入人体而产生潜在危害, 快速检测残留环己酮对PVC医疗器械的质量控制具有重要意义. 结合三重四极杆质谱和电喷雾萃取电离技术, 建成能够对痕量环己酮气体快速检测的电喷雾萃取电离-三重四极杆质谱仪(EESI-MS/MS). 通过对EESI电离源的喷雾电压、载气流速等条件进行优化, 得到最优喷雾电压为3000 V, 最佳载气流速为11.67 L/min, 装置响应时间小于2.5 s, 信号强度的相对标准偏差为4.83%, 仪器的检出限为237.1×10^-9 (V/V). 利用EESI-MS/MS实现了对PVC输液管中残留环己酮的快速检测, 配合串级质谱的子离子扫描功能实现了环己酮的准确定性, 同时计算得到PVC输液管中残留环己酮的浓度为362.6×10^-9 (V/V). 建立的EESI-MS/MS在PVC医疗器械质量控制方面具有重要的应用价值.