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排序方式: 共有582条查询结果,搜索用时 15 毫秒
1.
A feasibility analysis methodology adopted from reactive distillation is applied to membrane reactors. A model is formulated to depict the reactive liquid phase composition on the retentate side of a continuous type membrane reactor. The effects of both the chemical reaction kinetics and the membrane mass transfer kinetics on the feasible products are elucidated by means of retentate phase diagrams and bifurcation analysis. The proposed method can be applied to various membrane processes, independent of the specific structure of the membrane. Two quaternary reaction systems are considered to illustrate the methodology. In the first hypothetical system, it is shown how selective membranes can influence the sequence of effective volatilities which in turn affects the feasible products of the system. In the second example of practical importance, i.e. the heterogeneously catalysed synthesis of propyl acetate coupled with permeation through a porous polycarbonate membrane, the dusty gas model is applied to describe the component fluxes through the membrane. For the latter reaction system, the existence of reactive arheotrope is demonstrated. Arheotropes represent mass transfer controlled feasible products of membrane separation process. 相似文献
2.
Synthesis of oleyl oleate as a jojoba oil analog 总被引:2,自引:0,他引:2
N. Sánchez M. Martinez J. Aracil A. Corma 《Journal of the American Oil Chemists' Society》1992,69(11):1150-1153
Synthesis of a wax ester analog of jojoba oil was accomplished from oleic acid and oleyl alcohol with a zeolite as catalyst.
A full 23 factorial design at two levels has been used in the synthesis. The variables selected were temperature, reduced pressure
and initial catalyst concentration. The most important variable within the range studied was temperature. Reduced pressure
had a negative influence, and initial catalyst concentration showed a positive influence on the process. A response equation
has been determined for the yield of ester. The properties of the synthesized product are similar to those of natural jojoba
oil. 相似文献
3.
铌酸对酯化反应催化性能的研究 总被引:1,自引:0,他引:1
研究了新型固体酸催化剂铌酸对乙醇及异戊醇与乙酸酯化反应的催化性能、研究表明热处理温度对水洗法制备的铌酸催化剂的催化活性有显著影响,在350℃处理时活性达到极大值.与HZSM-5相比,铌酸催化剂不仅在乙醇和乙酸的气相酯化反应中表现出良好的催比性能,而且在异戊醇和乙醇的液相酯化反应中亦表现出较好的催化活性和稳定性. 相似文献
4.
己二酸二乙酯合成新工艺的研究 总被引:2,自引:0,他引:2
本文以离子交换树脂作为液固相酯化反应的催化剂 ,甲苯作为带水剂 ,合成己二酸二乙酯。应用本法 ,酯化反应产率高达 78%。同时对影响产率的诸因素进行了考察 ,其最佳反应条件为 :酸醇摩尔比 1∶4 ,催化剂用量为酸质量的 2 5 % ,反应时间为 10小时 ,反应温度 86~ 87℃ ,催化剂重复使用 4次 ,未出现活性明显下降 ,此工艺操作简单 ,反应条件温和 ,产率高 ,具有显著的工业应用价值。 相似文献
5.
《Chemical engineering science》2002,57(9):1557-1562
A catalytically active zeolite membrane has been used to displace equilibrium by selective water permeation during ethanol esterification. Unlike previous works in which water separation was carried out by zeolitic membranes that did not take part in the reaction, the H-ZSM-5 membrane used in this work had sufficient catalytic activity to carry out the esterification of ethanol with acetic acid, and at the same time was selective for water permeation. As a consequence, the reaction and separation functions could be coupled very efficiently, and the conversion obtained at the same feed rate and catalyst loading was greater than in conventional fixed bed reactors, or in reactors where the zeolite membrane was kept separated from the catalyst. 相似文献
6.
乙酰柠檬酸三丁酯的合成 总被引:10,自引:1,他引:10
用柠檬酸、正丁醇、乙酸酐为原料,经酯化和酰化两步反应合成乙酰柠檬酸三丁酯。考察了催化剂、原料配比、反应温度和反应时间等因素对合成反应的影响,确定了最佳反应条件。 相似文献
7.
用间歇式搅拌反应器,对丙酮氰醇(HCN)法甲基丙烯酸甲酯生产中水解和酯化反应的特性进行了研究。研究表明:(1)甲基丙烯酰胺硫酸盐的水解反应有较高的平衡转化率,其动力学方程为k1=6.52×10^6exp(-69.8/RT);(2)甲基丙烯酸与甲醇间酯化反应的平衡转化率较低,故生产中必须加以提高。测得的液相和汽-液相酯化反应的活化能分别为49.4kJ/mol和54.4kJ/mol。 相似文献
8.
9.
Douglas G. Hayes Robert Kleiman 《Journal of the American Oil Chemists' Society》1995,72(11):1309-1316
Eight lipases were screened for their ability to synthesize estolides from a mixture that contained lesquerolic (14-hydroxy-11-eicosenoic)
acid and octadecenoic acid. With the exception ofAspergillus niger lipase, all 1,3-specific enzymes (fromRhizopus arrhizus andRhizomucor miehei lipases) were unable to synthesize estolides.Candida rugosa andGeotrichum lipases catalyzed estolide formation at >40% yield, with >80% of the estolide formed being monoestolide from one lesquerolic
and one octadecenoic acyl group:Pseudomonas sp. lipase synthesized estolides at 62% yield, but the product mixture contained significant amounts of monoestolide with
two lesquerolic acyl groups as well as diestolide. ImmobilizedR. miehei lipase was chosen to catalyze the esterification of mono-and polyestolide, derived synthetically from oleic acid, with fatty
alcohols or α,ω-diols. Yields were >95% for fatty alcohol reactions and >60% for diol reactions. In addition, the estolide
linkage remained intact through the course of the esterification process. Esterification of estolides improved the estolide’s
properties—for example, lower viscosity and higher viscosity index—but slightly raised the melting point. Estolides and, particularly,
estolide esters may be suitable as lubricants or lubricant additives. 相似文献
10.
本文研究了TDE-85环氧树脂丙烯酸酯的合成方法,讨论了合成条件(催化剂的种类与用量,反应温度及时间,投料比,反应类型及不饱和酸种类的选择等)对合成反应及合成产物性状的影响。另外,还考察了该合成产物的UV固化特性。 相似文献