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31.
U. Sridevi Narayan C. Pradhan B.K.B. Rao C.V. Satyanarayana B.S. Rao 《Catalysis Letters》2002,79(1-4):69-73
The alkylation of benzene with isopropyl alcohol was studied in an integral pressure reactor over silicon substituted aluminophosphate molecular sieves, SAPO-5. The influence of various process parameters such as temperature, pressure, time on stream, weight hourly space velocity, and mole ratio of reactants on cumene yield and selectivity were investigated. The activity of SAPO-5 was compared with that of Hbeta for this reaction under similar conditions and in the same reactor. At pressures higher than atmospheric, almost the theoretical maximum yields of cumene were achieved on this SAPO-5. Among the diisopropyl benzenes formed by the alkylation of cumene, the meta-isomer was found to form in a significant amount followed by the para-isomer. The ortho-isomer with relatively high strain energy of 4.26 kcal/mol was almost negligible. The cumene yield goes through a maximum in the temperature range 498-543 K studied. Cumene selectivity was found to decrease at higher temperatures, higher pressures and lower benzene to isopropanol mole ratios. 相似文献
32.
从毛发中提取角蛋白,开发具有独特功能的角蛋白基药物载体材料,提高药物的活性和生物利用率,既能够增加毛发的利用价值,又能够实现节能减排,符合可持续发展战略要求。对毛发中提取角蛋白进行二硫键重建、自由基聚合、多糖改性和烷基化等改性处理,赋予角蛋白基药物载体优异地功能特性,进一步拓宽其作为角蛋白基药物载体的应用范围。角蛋白基药物载体可被加工成纳米粒子、纤维支架、水凝胶等各种形式用于药物的递送。作为一种高硫含量且具有良好细胞相容性的结构蛋白,角蛋白基药物载体在组织工程、再生医学等领域扮演着重要的角色。 相似文献
33.
介绍了中国石油抚顺石化公司石油二厂废硫酸裂解制酸装置的运行情况及转化工序存在的问题。对该工序进行了技术改造:更换了转化反应催化剂,调整转化工序换热流程,增加了换热器,去掉转化混合器,同时增加了转化工序设备和管线的保温层厚度。改造后装置运行平稳,硫酸转化率达到设计值,并多生产硫酸520万t/a,排放尾气中SO2的质量浓度低于960mg/m3,同时节约电耗100万kWh/a,实现了经济效益和环境效益的双增长。 相似文献
34.
解国宏 《硫磷设计与粉体工程》2006,(6):36-38
介绍了抚顺石化公司石油二厂15600 t/a废硫酸裂解制酸装置,通过技术改造,装置运行平稳,系统开车率提高,转化率达到设计值,排放尾气中SO2浓度小于960mg/m^3,达到了国家环保标准规定的限值要求,实现了经济效益和环境效益双增长。 相似文献
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研究开发了一次烷基化分离法生产高纯度均三甲苯新工艺,并对其进行了技术经济分析评价。生产实践表明,该工艺技术含量高,设备投资少,流程简单,容易操作,产品收率高,质量稳定,是理想的生产工艺。 相似文献
38.
This paper deals with in situ compatibilization of PE/PS blends via Friedel-Crafts reaction, performed at the interphase. Two polyethylenes having different molecular weights, and the same PS, were used along a wide range of catalyst concentration. The influence of the graft copolymer architecture and content on the efficiency of blend compatibilization was studied. The emulsifying effect, morphological aspects and mechanical behavior were also assessed for these blends. The amount of copolymer formed increases with catalyst concentration and the short chain length fraction of the homopolymers. The high molecular weight (MW) copolymers behaved as better compatibilizers as they showed, at the cmc, greater graft copolymer concentration than the low MW ones. A substantial increase in interfacial adhesion and particle size reduction was observed, even at catalyst concentrations as low as 0.3 wt%. In correspondence, mechanical properties, like ductility and yield strength, were enhanced by the effect of this Friedel-Crafts reaction's compatibilization. 相似文献
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40.
Levitsky K Boersma MD Ciolli CJ Belshaw PJ 《Chembiochem : a European journal of chemical biology》2005,6(5):890-899
Investigations on the scope and utility of exo-mechanism proximity-accelerated reactions in engineered receptor-ligand systems are reported. We synthesized a series of electrophilic cyclosporin (CsA) derivatives by varying electrophiles and linker lengths, prepared a series of nucleophilic cysteine mutations on the surface of cyclophilin A (Cyp), and examined their reactivity and specificity in proximity-accelerated reactions. Acrylamide and epoxide electrophiles afforded useful reactivity and high specificity for alkylation of engineered receptors in Jurkat cell extracts. We found that remote cysteines (>17 A from the ligand) could be alkylated with useful rates under physiological conditions. The results from mutations of the receptor surface suggest that the dominant factors governing the rates of proximity-accelerated reactions are related to the local environment of the reactive group on the protein surface. This study defines several parameters affecting reactivity in exo-mechanism proximity-accelerated reactions and provides guidance for the design of experiments for biological investigations involving proximity-accelerated reactions. 相似文献