共查询到18条相似文献,搜索用时 62 毫秒
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采用反应精馏技术以乙二醇和乙酸仲丁酯为原料,通过酯交换合成乙二醇二乙酸酯。使用Aspen Plus对反应精馏塔进行模拟与优化,其结果为:操作压力为70 kPa,精馏段理论板数为4,反应段理论板数为15,提馏段理论板数为4,酯醇摩尔比为3∶1,回流比为2,该条件下,乙二醇转化率和塔釜乙二醇二乙酸酯质量分数达99%以上。在模拟基础上,进行反应精馏小试实验,最终确定全塔26节塔节,乙二醇和乙酸仲丁酯分别在第4节和第23节进料,全塔操作压力为70 kPa,酯醇摩尔比为3∶1。回流比为2,乙二醇转化率为98.17%,塔釜乙二醇二乙酸酯质量分数为97.54%。实验与模拟结果在误差范围内,验证了模拟计算的可靠性,为工业化提供了理论基础。 相似文献
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乙二醇二乙酸酯的合成 总被引:7,自引:0,他引:7
讨论了金属氯化物为催化剂,用甲苯为脱水共沸剂,将乙二醇与乙酸进行酯化反应生成二醇二乙酸酯,经试验得出氧化锌具有较好的催化性能,另外,研究了催化剂用量,脱水共沸剂,酸醇比例等对酯收率的影响。 相似文献
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以甲基丙烯醛和无水醋酐为原料及强酸性阳离子交换树脂为催化剂合成了2.甲基烯丙基二乙酸酯,考察了催化剂用量、物料配比、反应温度及反应时间对反应的影响。确定了适宜的反应工艺条件:n(醋酐)/n(甲基丙烯醛)为1,2;强酸性阳离子交换树脂用量以甲基丙烯醛的用量(mol)为基准,2.0g/mol;反应时间5h,反应温度-10℃。在此条件下,甲基丙烯醛转化率为95.5%,2.甲基烯丙基二乙酸酯选择性和收率分别为95.7%和91.4%。并对产物进行了红外光谱表征,产物的红外谱图和标准谱图基本吻合。 相似文献
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酯交换法制备二丙烯酸乙二醇酯的研究 总被引:1,自引:0,他引:1
以丙烯酸甲酯(MA)与乙二醇(EG)为原料,采用酯交换法合成出了二丙烯酸乙二醇酯(EGDA),对合成反应中的主要条件进行了实验研究。结果表明,适宜的合成条件为:MA与EG物质的量之比为5∶1,且1 mol EG使用9 g对甲苯磺酸为催化剂,由对甲氧基苯酚与吩噻嗪按等质量比复配而成的复合阻聚剂14~16 g,空气通入速度为15 mL/m in,在此条件下合成的粗酯中EGDA含量为83.9%。粗酯经减压精馏后,EGDA产品纯度达99.9%以上。 相似文献
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Basevich V. Ya. Kogarko S. M. Posvyanskii V. S. 《Combustion, Explosion, and Shock Waves》1977,13(2):163-168
Combustion, Explosion, and Shock Waves - 相似文献
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David R. Fagerburg 《应用聚合物科学杂志》1985,30(9):3617-3623
The kinetics of the reaction of terephthalic acid with a number of ethylene carbonates in the presence of an amine catalyst were examined. All reactions apparently follow first-order kinetics; therefore, the solution rate of TPA is not rate-limiting. With minor adjustments, the mechanism appears to be in accord with that of the model reaction of benzoic acid and ethylene carbonate previously reported. Attack of the carboxylate on the carbonate ring must be the rate-limiting step. Substituent effects (owing to substituents on the carbonate ring) appear to be mostly steric in nature; surprisingly, an n-octyl group causes the slowest reaction. Besides being strongly influenced by steric hinderance, the transition state appears to be highly polar. Activation energy (16.0 kcal/mol) and activation entropy (?23.6 cal/deg) are very similar to those of the model reaction. 相似文献
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为了给乙酸正丁酯的工业生产提供动力学支持,文章在间歇搅拌釜式反应器中利用酯交换法将乙酸甲酯转化为乙酸正丁酯。首先筛选出Si-3为最优催化剂,然后考察了转速、反应温度、催化剂用量、醇酯比等因素对反应过程的影响,确定较优的实验条件为转速400 r/min,反应温度70℃,催化剂用量(质量分数)20%,醇酯比(摩尔比)为1.25∶1。在323—343 K下,将实验数据拟合后得到酯交换反应的动力学方程。正反应速率常数为6 291.15 L/(mol·s),正反应活化能50 134.7 J/mol;逆反应速率常数为137.72 L/(mol·s),逆反应活化能38 324 J/mol。通过实验与计算值的比较验证,此宏观动力学方程合理,可用于模拟计算。 相似文献
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Unlike two-step chemical vapor deposition (CVD) methods using pre-deposited catalyst particles, in a continuous-feed CVD process, the liquid feed (consisting of catalytic precursor and hydrocarbon source) is continuously supplied into the reactor causing catalyst particle formation, nucleation of carbon nanotubes (CNTs) and CNT growth to occur simultaneously throughout the reaction period. In order to observe these processes, CVD experiments were conducted for different durations (30 s to 3 h) and the product multiwalled carbon nanotubes (MWCNTs) were characterized using scanning electron microscopy. It was found that the nanotubes did not grow in the vapor phase and that substrates played an important role in the growth by providing a place for them to anchor before growth took place. Based on transmission electron microscopy images, it has been suggested that MWCNTs grew by root-growth mechanism from the catalyst particles that were deposited on the substrate during the early stages. At long process times, continuously supplied feed gas produced additional catalyst particles which were deposited mostly on the growing nanotube mat. Due to weak catalyst-mat interaction, the additional nanotubes grew by tip growth. A comprehensive MWCNT growth model has been presented for the continuous-feed CVD. 相似文献