Nitration of nitrobenzene at high‐concentrations of sulfuric acid: Mass transfer and kinetic aspects

This article reports studies on mass transfer and kinetics of nitration of nitrobenzene at high concentrations of sulfuric acid in a batch reactor at different temperatures. The effects of concentration of sulfuric acid, speed of stirring, and temperature on mass transfer coefficient were investigated. The kinetics of nitration under homogenized conditions was studied at different sulfuric acid concentrations at these temperatures. The reaction rate constants were determined. The variation of rate constant with sulfuric acid concentration was explained by the M_c function. The activation energies of the reactions were determined from the Arrhenius plots. The regimes of the reactions were determined using the values of the mass transfer coefficients and the reaction rate constants. A model was developed for simultaneous mass transfer and chemical reaction in the aqueous phase. The yields of the three isomers of dinitrobenzene were determined, and the variation of isomer distribution with sulfuric acid concentration and temperature was analyzed. This work demonstrates that more than 90% conversion of nitrobenzene is possible at high‐sulfuric acid concentrations resulting in high yield of the product even at moderate temperatures and at low speeds of stirring. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

氯苯肟唑(SPRI-WM-005)异构体的分离及其杀菌活性

氯苯肟唑（SPRI-WM-005）是含顺、反异构体的肟醚结构化合物。为了研究两个异构体及未分离的混合物在生物活性上是否存在差异,对两个异构体进行了分离,并做了对黄瓜白粉病的室内生物活性测定。结果表明,当处理剂量为50mg／L时,氯苯肟唑（Z,E混合物）、Z-氯苯肟唑和E-氯苯肟唑的防效分别为95％、100％和97％,三者活性基本相当,故在实际中无须将两个异构体分离,混合体可直接应用。     

结晶精馏耦合流程分离MDI同分异构体的新工艺

提出了一套关于结晶精馏耦合分离MDI同分异构体的工艺流程,该新工艺采用先结晶后精馏,精馏产物再返回结晶器的方法.分别对结晶和精馏流程进行了模拟分析,并从能耗角度对新工艺与原有工艺进行比较.结果表明,该结晶精馏耦合分离MDI同分异构体工艺所得结晶产品中4,4′-MDI纯度达到99%以上时,其能耗仅是真空精馏工艺能耗的1/2～2/7.新工艺工业化后将产生良好的经济效益.     

联苯四酸二酐几种异构体的合成方法

综述了以联苯四酸二酐为原料之一生产的聚酰亚胺的主要用途,介绍了联苯四酸二酐的三种异构体： 3,3＇,4,4＇-联苯四酸二酐、 2,2＇,3,3＇-联苯四酸二酐和 2,3＇,3,4＇-联苯四酸二酐们的几种合成路线,包括脱卤偶联法,氧化偶联法等.重点讨论了脱卤偶联反应的历程,以及 Pd/C或三苯基膦配体为催化剂的催化机理     

超声波处理对涤纶织物聚氨酯涂层中4,4'-二氨基二苯甲烷的影响

针对二甲苯溶剂脱色含聚氨酯涂层涤纶织物样品中4,4’-二氨基二苯甲烷的检出率高,结果差异大的问题,分别采用邻二甲苯、间二甲苯、对二甲苯作为萃取溶剂,通过超声波萃取涤纶织物的聚氨酯涂层,研究超声波处理时间、处理温度、分散剂种类、分散剂体积分数等条件对4,4’-二氨基二苯甲烷质谱峰面积的影响。结果表明:乙腈作为分散剂进行转移时,目标物峰面积最大;当乙腈体积分数分别为50%、70%、70%时,邻二甲苯、间二甲苯和对二甲苯萃取残留物的目标物峰面积最大;超声波处理温度分别为40、50、60℃时,对二甲苯、邻二甲苯、间二甲苯作为萃取溶剂时的目标物峰面积达到顶点;超声波处理时间为45～50 min时,3种萃取溶剂的萃取效率最优。     

Analysis of sulfoxylated methyl esters (Φ-MES): Sulfonic acid composition and isomer identification

Derivatization of a C₁₂Φ-methyl ester sulfonic acid by using iodide-trifluoroacetic anhydride in dimethylformamide in a one-step reaction yielded derivatized sulfonic thiotrifluoroacetates. The latter have been analyzed by gas chromatography-mass spectrometry (MS) and liquid chromatography-MS techniques so that, for the first time, the acid composition and the mono sulfonic acid isomer distribution are shown.