Preparation,characterization and application of polyaniline/epoxide polysiloxane composite films

Composites of polyaniline(PAn) and epoxide polysiloxane(EPSi) are reported for the first time. EPSi is designed, synthesized and N-grafted onto the PAn backbone through covalent bonds. As-prepared EPSi-g-PAn composites are soluble in organic solvents and the corresponding films can be easily produced via a simple solution-casting procedure. The composite films combine the mechanical characteristics of EPSi and the chemical properties of PAn, enabling the facile introduction of the noble metal particles. The successful fabrication of the composites is confirmed by the investigation of the molecular structure, crystalline structure and microstructure of the materials. The resulting composite films containing noble metal particles are employed as the catalysts for the hydrogenation of phenol to produce cyclohexanone, which exhibit the convenience and recyclability for usage as well as the high catalytic activities, including the conversion ratio of 97%-100% and the selectivity as high as 84%-98%. The present work not only provides a new method to improve the processability of the conducting polymers but also describes a kind of composite materials that may display outstanding preformances in industrial catalysis.     

Regioselective ring opening of epoxides using NH4SCN/silica sulfuric acid: An efficient approach for the synthesis of β-hydroxy thiocyanate under solvent-free conditions

Silica sulfuric acid was developed as a stable and efficient heterogeneous catalyst in organic synthesis. This solid acid catalyzed the regioselective ring opening of epoxides by thiocyanate anion to give thiocyanohydrins as key intermediates in agricultural and pharmaceutical chemistry in high yields under solvent-free conditions.     

CH2和CH3分子在金属团簇Cun(n=1～6)上吸附性质

以σ-羟基环氧化合物作为模型化合物, 利用密度泛函中B3LYP/6-31G(d,p)的方法研究了三乙基铝促进的环氧化合物的重排还原有机串联反应机理. 根据乙烯消去和六元环重排顺序的不同可有两条可能的反应路径,路径I首先进行的是六元环的收缩重排,而且该步即决速步,能垒为116.62 kJ/mol;路径II中首先发生乙烯的消去然后进行六元环开环重排,开环反应步是该反应路径的决速步,相应的能垒为251.38 kJ/mol,如此高的能垒导致后续反应难于进行. 因此,路径I是更有利的反应路径,与实验结果一致.     

Biocatalytic Resolution of para‐Nitrostyrene Oxide by Resting Cells of Different Aspergillus niger Strains

Biocatalytic resolution of racemic para‐nitrostyrene oxide was accomplished by employing the epoxide hydrolases from the whole cells of several Aspergillus niger (A. niger) strains. In the cases investigated, excellent selectivity was achieved with such strains as A. niger 5450, A. niger 5320.     

Steric effects in the tetracyanoethylene catalysed methanolysis of some cyclohexane epoxides

The presence of a hydroxyl group has been shown to direct the regiochemistry and stereochemistry of the TCNE methanolysis of cyclohexane hydroxy-epoxides. α-Pinene epoxide underwent cleavage to form the 8-methyl ether of trans-sobrerol.     

Direct conversion of epoxides to vic-difluorides

vic-Difluoro compounds can be directly prepared from epoxides by reaction with Et₃N-3HF and DFMBA under microwave-irradiation conditions.     

Synthesis and cationic polymerization of oxyranyl-functionalized triphenylamine

Synthesis and cationic polymerization of N-{4-[(oxiranylmethoxy)methyl]phenyl}-N,N-diphenylamine is reported. Diaryliodonium salts and iron-arene complex were used as photoinitiators. Iodonium salts have appeared to be much more effective photoinitiators for polymerization of the monomer than iron-arene complex. The effect of the temperature on the rate of photopolymerization of the monomer with iron-arene complex has been studied.     

Influence of temperature and nature of photoinitiator on the formation kinetics of an interpenetrating network photocured from an epoxide/methacrylate system

This paper deals with the synthesis of an interpenetrating network made of dimethacrylate and dicycloepoxide oligomers by photopolymerization. More particularly, the influence of several parameters (among which the photoinitiator nature and the reaction temperature) on the polymerization kinetics of each oligomer was studied. Two complementary analysis techniques were then used : the photocalorimetry and the RTIR spectroscopy. The study proceeded in several steps. Firstly, photopolymerization of each monomer was studied. Then, the same study was carried out on mixture of both monomers under conditions in such way than only one network is formed. It was shown that the second compound played the role of plasticizer on the network formed by the first monomer. Finally, the dimethacrylate/dicycloepoxide mixture was studied in the presence of both radical and cationic photoinitiators to synthesize an interpenetrating network (IPN). At 30 °C, ultimate products show a very incomplete epoxide conversion whereas the yield in methacrylic double bonds reaches 70%. On the other hand, epoxy functions react a little more than methacrylic double bonds at 90 °C. It was also shown that the presence of a radical photoinitiator is not necessary, and even slightly unfavourable, since the cationic photoinitiator is able to initiate both radical and cationic polymerization mechanisms.     

A mild and efficient synthesis of β-amino alcohols from epoxides using a mesoporous aluminosilicate catalyst

Mesoporous aluminosilicates catalyze efficiently the ring-opening reactions of a range of epoxides with aromatic amines to produce β-substituted alcohols in high yields under mild reaction conditions.     

分子筛催化下环氧氯丙烷开环反应的溶剂效应

环氧化合物与羧酸的开环加成酯化是有机化学中一类重要反应,开环形成的羧酸β-羟基酯有着十分广泛的用途。这类反应的进行通常需要高活性的催化剂,我们曾将Fe(Ⅲ)改性的ZSM-5分子筛应用于羧酸β-羟基酯的合成。本文用Fe-ZSM-5分子筛为催化剂,以环氧氯丙烷与丙酸反应作为模型,研究了取代苯为溶剂时对反应速率的影响,发现反应的速率