A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the ...A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the product stream containing ethylbenzene was used to heat the reactor vessel, which consisted of an alkylation section, an upper heat exchange section, and a bottom heat exchange section. In such a novel reactor, vapor phase benzene and liquid phase benzene were coexisted due to the heat produced by isothermal reaction between the upper heat exchange section and the bottom heat exchange section. The process was demonstrated by the thermodynamic analysis and experimental results. In fact, during the 1010 hour-life-test of gas phase ethene with gas phase-liquid phase benzene alkylation reaction, the ethene conversion was above 95%, and the ethylbenzene selectivity was above 83% （only benzene feed） and even higher than 99% （benzene plus transalkylation feed）. At the same time, the xylene content in the ethylbenzene was less than 100 ppm when the reaction was carried out under the reaction conditions of 140-185℃ of temperature, 1.6-2.1 MPa of pressure, 3.0-5.5 of benzene/ethylene mole ratio, 4-6 v% of transalkylation feed/（benzene＋transalkylation feed）, 0.19-0.27 h^-1 of ethene space velocity, and 1000 g of 3998 catalyst loaded. Thus, compared with the conventional ethylbenzene synthesis route, the transalkylation reactor could be omitted in this novel industrial process.展开更多
In order to simulate the instability phenomenon of a nonaqueous phase liquid(NAPL) dissolution front in a computational model, the intrinsic characteristic length is commonly used to determine the length scale at whic...In order to simulate the instability phenomenon of a nonaqueous phase liquid(NAPL) dissolution front in a computational model, the intrinsic characteristic length is commonly used to determine the length scale at which the instability of the NAPL dissolution front can be initiated. This will require a huge number of finite elements if a whole NAPL dissolution system is simulated in the computational model. Even though modern supercomputers might be used to tackle this kind of NAPL dissolution problem, it can become prohibitive for commonly-used personal computers to do so. The main purpose of this work is to investigate whether or not the whole NAPL dissolution system of an annular domain can be replaced by a trapezoidal domain, so as to greatly reduce the requirements for computer efforts. The related simulation results have demonstrated that when the NAPL dissolution system under consideration is in a subcritical state, if the dissolution pattern around the entrance of an annulus domain is of interest, then a trapezoidal domain cannot be used to replace an annular domain in the computational simulation of the NAPL dissolution system.However, if the dissolution pattern away from the vicinity of the entrance of an annulus domain is of interest, then a trapezoidal domain can be used to replace an annular domain in the computational simulation of the NAPL dissolution system. When the NAPL dissolution system under consideration is in a supercritical state, a trapezoidal domain cannot be used to replace an annular domain in the computational simulation of the NAPL dissolution system.展开更多
由于在医疗行业、畜牧养殖业和农业生产活动中的广泛使用,氨基糖苷类抗生素(Aminoglycosides,AGs)在食品介质中广泛残留。但由于其种类多样,且具有强极性,分子结构上缺乏发色和荧光基团等特点,目前该类物质的同时测定分析方法要比其他...由于在医疗行业、畜牧养殖业和农业生产活动中的广泛使用,氨基糖苷类抗生素(Aminoglycosides,AGs)在食品介质中广泛残留。但由于其种类多样,且具有强极性,分子结构上缺乏发色和荧光基团等特点,目前该类物质的同时测定分析方法要比其他类抗生素更为复杂。在已报道的多种检测方法中,液相色谱-串联质谱法(Liquid Chromatography-Tandem Mass Spectrometry,LC-MS/MS)在食品介质中多种AGs的同时测定中发挥重要作用。综述了LC-MS/MS用于检测食品中氨基糖苷类抗生素残留的前处理方法和仪器条件,以及AGs在食物中的污染现状,以期为食品中氨基糖苷类抗生素的残留分析提供理论参考。展开更多
目的建立血液中河豚毒素的净化富集及检验方法。方法通过考察多种亲水性色谱柱,不同类型固相萃取柱萃取效果及杂峰对定性离子对的干扰分析等方法,降低河豚毒素的基质影响,提高检测灵敏度及定性准确性。结果河豚毒素极性大,易受基质抑制...目的建立血液中河豚毒素的净化富集及检验方法。方法通过考察多种亲水性色谱柱,不同类型固相萃取柱萃取效果及杂峰对定性离子对的干扰分析等方法,降低河豚毒素的基质影响,提高检测灵敏度及定性准确性。结果河豚毒素极性大,易受基质抑制,而常规沉淀蛋白法灵敏度低并出现异构体双峰,且C18色谱柱无保留;经综合比较分析,最终采用弱阳离子交换柱PWC柱进行净化富集,以0.5 mL 10%甲酸50%乙腈水溶液即可洗脱完全,经Atlantis hilic色谱柱分离,以320.10>162.15,284.15作为定性离子对,方法检出限可达0.061ng/mL。结论建立固相萃取PWC-液质联用仪检测方法,净化效果明显,基质影响小,色谱峰无干扰,较大地提高了检测灵敏度,且操作简便,重现性好,可应用于相关案件的检验。展开更多
基金This work is supported by the National 973 Project of China (2009CB623501)
文摘A novel industrial process was designed for the highly selective production of ethylbenzene. It comprised of a reactor vessel, vapor phase ethylene feed stream, benzene and transalkylation feed stream. Especially the product stream containing ethylbenzene was used to heat the reactor vessel, which consisted of an alkylation section, an upper heat exchange section, and a bottom heat exchange section. In such a novel reactor, vapor phase benzene and liquid phase benzene were coexisted due to the heat produced by isothermal reaction between the upper heat exchange section and the bottom heat exchange section. The process was demonstrated by the thermodynamic analysis and experimental results. In fact, during the 1010 hour-life-test of gas phase ethene with gas phase-liquid phase benzene alkylation reaction, the ethene conversion was above 95%, and the ethylbenzene selectivity was above 83% （only benzene feed） and even higher than 99% （benzene plus transalkylation feed）. At the same time, the xylene content in the ethylbenzene was less than 100 ppm when the reaction was carried out under the reaction conditions of 140-185℃ of temperature, 1.6-2.1 MPa of pressure, 3.0-5.5 of benzene/ethylene mole ratio, 4-6 v% of transalkylation feed/（benzene＋transalkylation feed）, 0.19-0.27 h^-1 of ethene space velocity, and 1000 g of 3998 catalyst loaded. Thus, compared with the conventional ethylbenzene synthesis route, the transalkylation reactor could be omitted in this novel industrial process.
基金Project(11272359)supported by the National Natural Science Foundation of China
文摘In order to simulate the instability phenomenon of a nonaqueous phase liquid(NAPL) dissolution front in a computational model, the intrinsic characteristic length is commonly used to determine the length scale at which the instability of the NAPL dissolution front can be initiated. This will require a huge number of finite elements if a whole NAPL dissolution system is simulated in the computational model. Even though modern supercomputers might be used to tackle this kind of NAPL dissolution problem, it can become prohibitive for commonly-used personal computers to do so. The main purpose of this work is to investigate whether or not the whole NAPL dissolution system of an annular domain can be replaced by a trapezoidal domain, so as to greatly reduce the requirements for computer efforts. The related simulation results have demonstrated that when the NAPL dissolution system under consideration is in a subcritical state, if the dissolution pattern around the entrance of an annulus domain is of interest, then a trapezoidal domain cannot be used to replace an annular domain in the computational simulation of the NAPL dissolution system.However, if the dissolution pattern away from the vicinity of the entrance of an annulus domain is of interest, then a trapezoidal domain can be used to replace an annular domain in the computational simulation of the NAPL dissolution system. When the NAPL dissolution system under consideration is in a supercritical state, a trapezoidal domain cannot be used to replace an annular domain in the computational simulation of the NAPL dissolution system.
文摘由于在医疗行业、畜牧养殖业和农业生产活动中的广泛使用,氨基糖苷类抗生素(Aminoglycosides,AGs)在食品介质中广泛残留。但由于其种类多样,且具有强极性,分子结构上缺乏发色和荧光基团等特点,目前该类物质的同时测定分析方法要比其他类抗生素更为复杂。在已报道的多种检测方法中,液相色谱-串联质谱法(Liquid Chromatography-Tandem Mass Spectrometry,LC-MS/MS)在食品介质中多种AGs的同时测定中发挥重要作用。综述了LC-MS/MS用于检测食品中氨基糖苷类抗生素残留的前处理方法和仪器条件,以及AGs在食物中的污染现状,以期为食品中氨基糖苷类抗生素的残留分析提供理论参考。
文摘目的建立血液中河豚毒素的净化富集及检验方法。方法通过考察多种亲水性色谱柱,不同类型固相萃取柱萃取效果及杂峰对定性离子对的干扰分析等方法,降低河豚毒素的基质影响,提高检测灵敏度及定性准确性。结果河豚毒素极性大,易受基质抑制,而常规沉淀蛋白法灵敏度低并出现异构体双峰,且C18色谱柱无保留;经综合比较分析,最终采用弱阳离子交换柱PWC柱进行净化富集,以0.5 mL 10%甲酸50%乙腈水溶液即可洗脱完全,经Atlantis hilic色谱柱分离,以320.10>162.15,284.15作为定性离子对,方法检出限可达0.061ng/mL。结论建立固相萃取PWC-液质联用仪检测方法,净化效果明显,基质影响小,色谱峰无干扰,较大地提高了检测灵敏度,且操作简便,重现性好,可应用于相关案件的检验。
