钇、钪分离工艺的新进展

本文简要介绍中国科学院长春应用化学研究所近年来在钇、钪分离工艺研究方面的新进展。     

混合溶剂对Ru(Ⅳ)萃取的研究

一、前言 在一定浓度盐酸介质中,Ru(Ⅳ)以RuCl_6~(2-)络阴离子状态存在,可被C类溶剂TOA(三辛胺)以离子缔合机制定量地萃入有机相。由实验得到在相同条件下,TOA对Ru(Ⅳ)的萃取率随稀释剂介电常数的增加而下降。     

钛合金粉末注射成形溶剂脱脂工艺研究

采用粉末注射成形方法制备了钛合金坯体，然后利用溶剂脱脂方法脱除坯体中可溶性粘结剂。通过对溶剂脱脂动力学分析表明，在脱脂过程中，存在动力学控制步骤转化的过程，提出了脱脂临界厚度的概念。当厚度超过5mm时，试样脱脂过程受扩散控制，在常温下进行溶剂脱脂时，其扩散系数为1．86×10^-6cm^2·s^-1，活化能为12．96kJ．mol^-1.K^-1；在厚度小于5mm时，试样脱脂过程受粘结剂溶解和扩散混合控制。     

Enzymatic Synthesis of Glucose- and Xylose Laurate Esters Using Different Acyl Donors,Higher Substrate Concentrations,and Membrane Assisted Solvent Recovery

Glucose- and xylose laurate esters are enzymatically synthesized using equimolar substrate concentrations in 2-methyl-2-butanol, comparing free lauric acid with methyl- and vinyl-laurate as acyl donors. All reactions result in ≥70% acyl donor conversions after 72 h but the activated donors are also partially hydrolyzed to lauric acid, highlighting the difficulty in controlling water presence in this particular reaction system. The esterification of xylose generates a complex product profile, with several regioisomers of monoesters and diesters. The esterification of glucose is quite selective, forming mainly the 6-O monoester (≥96%) with a small presence of two diester isomers (4%). Increasing substrate concentration up to 800 millimoles kg⁻¹ results in lower conversion values (down to 58%) but shows that the reaction proceeds successfully even in the presence of high amounts of insoluble glucose. However, the reaction is less selective and the proportion of diester increases, becoming up to 46% (molar fraction) of the final product. Solvent recovery after esterification can be achieved by organic solvent nanofiltration through a polymeric membrane able to retain ≥80% of all reaction substrates and products. Practical Applications: The use of high substrate concentrations during the enzymatic synthesis of sugar ester biosurfactants leads to product titers that are more industrially appealing, without the need to find a solvent that can solubilize all initial substrate. The sustainability of the enzymatic conversion at mild temperatures can be enhanced by recycling of the reaction solvent through organic solvent nanofiltration, an energy efficient alternative to other traditional methods like distillation.     

转盘塔内甲基异丁基酮萃取湿法磷酸实验研究

溶剂萃取法是一种经济有效的湿法磷酸净化方法。在转盘塔中,以甲基异丁基酮（MIBK）为萃取剂,开展了净化湿法磷酸的实验研究。考察了搅拌转速、相比对磷酸萃取率、杂质离子选择性、洗涤效果和反萃效果的影响。研究结果表明：萃取过程适宜的相比（溶剂与磷酸的体积比）为4,搅拌转速为200~400 r/min,在此条件下磷酸萃取率为85%;洗涤过程的搅拌转速不应大于100 r/min,适宜的洗涤酸用量为溶剂相体积的10%~15%,在此条件下铁离子（Ⅲ）和镁离子脱除率均在90%以上、铝离子脱除率大于70%、硫酸根脱除率为50%~60%;反萃过程搅拌转速不应大于200 r/min,适宜的反萃水用量为溶剂相体积的9%~15%。MIBK对阳离子的脱除效果较好,但是对阴离子的脱除效果不佳。经过萃取、洗涤和反萃3个过程,磷酸收率为57.8%~70.3%,磷酸中铁离子（Ⅲ）含量可以达到工业级磷酸标准,但是硫酸根的含量无法达标,需要结合其他方法进一步脱除。     

N-甲酰吗啉芳烃抽提塔试验研究

用小型碳钢筛板萃取塔进行了宽馏分重整脱庚烷油的N 甲酰吗啉抽提试验 ,考察了抽提温度、溶剂比、溶剂含水率对总芳烃收率及选择性的影响。结果表明 ,在抽提温度为 60℃、溶剂含水为 3 % (m )和溶剂比S/F =4(V)的抽提操作条件下 ,溶剂选择性较高 ,并可获得高的芳烃回收率     

表面活性剂包衣脂肪酶在有机溶剂中催化酯合成

用合成的谷氨酸二烷基酯核糖醇对来源于Candidarugosa的脂肪酶进行了包衣 ,以月桂酸与月桂醇的酯化为模型反应 ,研究了各种操作条件对包衣酶活性的影响。结果表明 ,包衣酶制备过程中的缓冲溶液的最适 pH为 6.8,谷氨酸双十二烷基酯核糖醇的包衣效果最好 ,最适反应温度为 3 0℃ ,最佳溶剂为异辛烷。在 10h内底物转化率达 94%。     

二甲基甲酰胺的生产

二甲基甲酰胺是性能优良的溶剂和化工原料，尤其是高纯二甲基甲酰胺在聚氨酯合成革、聚丙烯腈纤维生产中有独特的用途。本文介绍二甲基甲酰胺的生产方法和国内外生产情况。     

醋酸丁酸纤维素淡酸分离装置的技术改造

针对醋酸丁酸纤维素淡酸分离装置操作难以稳定,无法进行连续生产且达不到淡酸分离要求的问题,分析了问题产生的原因,并对原装置进行技术改造,增强了操作控制手段,增设了轻相液体分布器,将脱酯塔提馏段改为板式结构并使用耐酸材料等。改造后,装置运行稳定,淡酸分离各项技术指标均达到设计要求。     

Determination of tetrachloroethylene—Results of a collaborative study and the standardized method

The development, by collaborative study, of a standardized method for the determination of tetrachloroethylene in olive oils is described. The results of the study, which was carried out in 1989 under the direction of the International Olive Oil Council (IOOC), are presented and show that tetrachloroethylene can be readily determined, to an acceptable degree of precision, by gas-liquid chromatography with electron capture detection. A limited number of results obtained for the determination of trichloroethylene and chloroform by the same method indicate that a similar precision could be obtained with the method when determining these solvents also.