Applications of phase-transfer catalytic reactions to fatty acids and their derivatives: Present state and future potential

Phase-transfer catalysts (PTC), which accelerate reactions between liquid(organic)-liquid(water) and liquidsolid heterogeneous states, have been investigated and developed. Several processes with PTC have succeeded in industrial processes involving fatty acids and their derivatives. For example, preparation of fatty alkyl glycidyl ethers, from which fatty alkyl glyceryl ethers and their derivatives can be obtained, has been carried out with PTC. However, some problems remain to be solved. For example, preparation of the fatty alkyl glycidyl ether by a PTC reaction was considered, but typical problems to be solved included: (i) how to reuse or recover the catalysts; (ii) how to control the heterogeneous reaction without obstacles to produce useful chemical materials; (iii) how to satisfy the environmental requirements for the catalysts; and (iv) are there more effective catalysts? We address these problems based on our own experiences with phase-transfer catalytic Williamson ether syntheses of fatty alkyl glycidyl ethers. Moreover, we describe recent developments in phase-transfer catalytic reactions related to oleochemistry, such as transition metal-catalyzed reactions of long-chain olefins in liquid(organic)-liquid(water) or liquid-solid heterogeneous states. Based on these results, we have considered the potential of PTC as a synthetic tool in oleochemistry.     

Stabilization of native penicillin G acylase by ionic liquids

Five different ionic liquids, based on dialkylimidazolium cations associated with perfluorinated and bis{(trifluoromethyl)sulfonyl}imide anions, were used to investigate the scope and limitations of these new solvents as media for penicillin G acylase‐catalyzed reactions. Deactivation of the native enzyme in ionic liquids (ILs) and in organic solvents (toluene, dichloromethane and 2‐propanol) at low water content and 40 °C was investigated using the hydrolysis of penicillin G as activity test. Native penicillin G acylase shows greater stability in IL media than in organic solvents. For example, a half‐life time of 23 h was obtained in 1‐ethyl‐3‐methylimidazolium bis{(trifluoromethyl)sulfonyl}imide, [emim⁺][Tf₂N^?], which was about 2000‐fold higher than that in 2‐propanol. An enhancement of the PGA stability was observed by the presence of substrate in ionic liquids based on tetrafluoroborate and hexafluorophosphate anions, achieving the highest increase of the half‐life time in 1‐butyl‐3‐methylimidazolium hexafluorophosphate ([bmim⁺][PF₆^?]), which was about 9‐fold higher than the half‐life time in the absence of substrate. Copyright © 2007 Society of Chemical Industry     

Information and the regulation of biotechnology

The reactivity of trivalent chromium salts towards collagen, the main protein in animal skins, was investigated in organic solvents on lamb skins of controlled water content. The optimal conditions were determined by experiment modelling. Complete exhaustion of the tanning baths, and much higher chromium binding was observed with this system than with traditional processes carried out in aqueous media.     

Low-Fat Bologna and Beaker Sausage: Effects of Carrageenans and Chloride Salts

Two meat products, regular bologna and bologna-like beaker sausage, were used to test performance of low-fat bologna batters prepared with two chloride salts (NaCl or KCl) and two carrageenan types (kappa or lambda). In the beaker sausage, two carrageenan-salt combinations lowered cooking loss compared to controls, and lambda-carrageenan in the presence of potassium cations was most effective. In regular bologna, none of the carrageenan-salt combinations lowered the cooking loss usually resulting with large amounts of added water. Also, treatments with lambda-carrageenan were less firm than high-fat or low-fat controls.     

Sulfonium-based Ionic Liquids Incorporating the Allyl Functionality

A series of sulfonium halides bearing allyl groups have been prepared and characterized. Anion metathesis with Li[Tf₂N] and Ag[N(CN)₂] resulted in sulfonium-based ionic liquids which exhibit low viscosities at room temperature. The solid state structure of one of the halide salts was determined by single crystal X-ray diffraction.     

A feasibility study of scaling-up the electrolytic production of carbon nanotubes in molten salts

The feasibility of scaling-up the electrolytic production of carbon nanotubes in molten salts has been investigated with the aid of electron microscopy (TEM and SEM). Using molten LiCl as the electrolyte and commercial graphite as both cathode and anode materials, carbon nanomaterials, including nanotubes, were prepared by constant voltage electrolysis. The cell was more than 20 times as large as that used in previous work. The nanotube concentration in the final product increased with cell voltage (including iR drop) from 1 vol.% at 4.0 V to 35 vol.% at 8.4 V. Under desired conditions, the charge and energy consumption for the cathode erosion was 0.28 Ah/g and 4.1 Wh/g, of which 60-70 wt.% were for producing nanomaterials (nanotubes: >30 vol.%). When adding 1 wt.% SnCl₂ to the electrolyte, partial and fully filled nanotubes were obtained with the nanomaterials containing up to 20 wt.% Sn. Preliminary results from applying the product as the electrode in lithium ion batteries are reported.     

NAEM—ASAM制浆过程中木素和碳水化合物的溶出规律

研究了中性碱土金属盐（NAEM）催化的碱性亚硫酸钠溶液中添加蒽醌和甲醇（ASAM）法制浆的机理，结果表明，NAEM＋ASAM法蒸煮对木素具有良好的选择性，从而改善了碳水化合物的稳定性，成浆具有高的半纤维素保留率。     

硫酸盐还原菌杀菌剂的合成及机理探讨

介绍了两种双季铵盐类化合物(杀菌剂1号,2号)的合成路线,并对其合成条件进行了探索,在此基础上进行了硫酸盐还原菌(SRB)的杀菌性能试验和杀菌机理探讨。当药剂浓度为80～100mg/L时,合成的两种双季铵盐对SRB的杀菌性能均优于通常使用的十二烷基二甲基苄基氯化铵(1227),而且杀菌剂1号优于2号,这是由于两个季氮原子之间所连的基团结构不同所致。     

氧化钙固硫反应动力学中的计算机模拟碱金属离子效应

研究了用催化剂提高CaO固硫率的可行性及其催化剂对固硫反应动力学的影响。用热天平研究了在CaO中添加不同催化剂后的固硫反应的进程,并用等效粒子模型来模拟和处理实验数据,计算了固硫反应动力学参数。结果表明,CaO固硫反应初期为表面化学反应控制阶段,后期转为产物层扩散控制阶段。碱金属的盐类催化剂均能使固硫反应前期的化学反应控制阶段的反应活化能E_α下降。E_α的大小按催化剂中Li~ 、Na~ 、K ~ 、Cs~ 离子半径增大的顺序依次递减;而碱金属盐类催化剂使固硫反应后期的产物层扩散控制阶段的反应活化能E_P不同程度地增加。     

锂离子电池电解质锂盐研究进展

介绍了锂离子电池电解质锂盐的化学和电化学。综述了近年来在新型电解质锂盐研究与探索方面的成果。新型电解质锂盐主要包括三类化合物 :(1 ) Li TFSI及其类似物 ;(2 )络合硼酸锂 ;(3 )络合磷酸锂。文章最后阐述今后电解质锂盐研究的可能发展方向及研究方法