共查询到17条相似文献,搜索用时 140 毫秒
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针对甲缩醛的合成方法,一方面以催化剂类型为主线,对醇醛缩合法、甲醇直接氧化法、二甲醚氧化法等进行了综述,并指出目前方法中存在的问题,如原料转化率低、产物纯度不高、催化剂稳定性差、工艺复杂等,进而指明甲缩醛合成应向着简化工艺、采用环保型催化剂、提高转化率和产品纯度的方向发展;另一方面,综述了国内外在甲缩醛合成反应动力学研究方向的进展情况,指出甲缩醛合成反应动力学的研究从模型的建立到装置的选择上都越来越接近工业生产的实际情况,对于工业化生产更具参考价值。甲缩醛合成动力学研究正在向着更加趋近于工业化生产的方向发展,可以为甲缩醛生产工艺和装置的建立提供更加有效的参考。 相似文献
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考察了以CuBr_2与具有不同烷基支链和阴离子类型的吡啶离子液体组成的催化剂体系对甲醇一步液相氧化合成甲缩醛(DMM)的催化性能,发现CuBr_2-N-乙基吡啶溴盐催化性能最好。考察了不同催化剂组成、催化剂浓度、反应温度、氧气压力、反应时间对甲醇一步液相氧化合成甲缩醛反应的影响,得到的最佳反应条件为:n(CuBr_2)/n(N-乙基吡啶溴盐)=1.0、催化剂质量浓度为40 g/L、反应温度130℃、氧气压力3 MPa和反应时间4 h,在该条件下甲醇转化率达到26.1%,DMM选择性达到95.0%。CuBr_2-N-乙基吡啶溴盐重复使用9次后,甲醇转化率为22.2%,DMM选择性为91.2%,催化活性仍然保持稳定。 相似文献
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甲缩醛反应精馏过程模拟 总被引:4,自引:0,他引:4
通过实验取得了甲醛和甲醇合成甲缩醛的反应参数;建立了其连续生产工艺的数学模型,利用ASPEN PLUS软件对甲醛和甲醇缩合生成甲缩醛进行了模拟,结果表明反应精馏连续生产甲缩醛的工艺是可行的,转化率高达99%,并得到含甲缩醛99%的产物,同时确定了进料板和反应区. 相似文献
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甲缩醛—甲醇—甲醛—水四元系的汽液平衡 总被引:4,自引:0,他引:4
甲缩醛-甲醇-甲醛-水四元系的汽液平衡邱祖民骆赞椿胡英(南昌大学化工系,南昌330029)(华东理工大学化工系,上海200237)关键词沸点仪汽液平衡甲缩醛甲醇甲醛甲醛虚拟饱和蒸汽压1前言甲缩醛-甲醇-甲醛-水四元系的汽液平衡数据为甲缩醛氧化制甲醛... 相似文献
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J. Masamoto T. Iwaisako M. Chohno M. Kawamura J. Ohtake K. Matsuzaki 《应用聚合物科学杂志》1993,50(8):1299-1305
A new technology for the production of highly concentrated aqueous formaldehyde was developed by oxidizing methylal. Whereas the oxidation of methanol yields 1 mol of water per 1 mol of formaldehyde, methylal oxidation produces only 1 mol of water for every 3 mol of formaldehyde. Thus, the output from methylal oxidation is more than 70% formaldehyde compared with 55% from methanol oxidation. For this purpose, basic research for methylal synthesis was tried and the world's first commercial production of methylal was accomplished. Using this methylal, the world's first technology of methylal oxidation for manufacturing highly concentrated aqueous formaldehyde was established by development of a new methylal oxidation catalyst composed of iron, molybdenum, and a third component. This highly concentrated aqueous formaldehyde is then fed to the acetal homopolymer and copolymer plant whose combined capacity is 35,000 tons/years. © 1993 John Wiley & Sons, Inc. 相似文献
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围绕碳酸二甲酯的高效、绿色、安全、节能合成目标,构建了联合生产碳酸二甲酯、甲缩醛和二甲醚反应体系及节能工艺。借助Aspen Plus软件对独立反应及复杂体系进行了热力学分析。由结果可知,升高反应压力或降低温度可明显提高碳酸二甲酯的平衡组成;与甲缩醛和二甲醚合成工艺相耦合后,可大幅提升甲醇平衡转化率,由0.5%~5.9%提高到91.7%~96.3%。根据热力学计算结果和动力学因素,提出顺序生产碳酸二甲酯、甲缩醛和二甲醚的串联催化反应器工艺。甲缩醛和二甲醚的分离采用简单精馏方式,碳酸二甲酯和水共沸物的分离采用变压精馏,3种产品的质量浓度均可达到99%以上。可有效解决单独生产碳酸二甲酯和甲缩醛生产中原料循环量大、能耗高和易爆炸等缺陷。 相似文献
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针对由甲醇、甲醛溶液合成甲缩醛反应。采用不同制备方法制备了四种不同组成的硅酸铝固体酸催化剂,在间歇操作方式下,通过改变催化剂用量、反应温度、原料甲醇和甲醛的摩尔配比以及反应原料中甲醛初浓度.考察了反应混合物中反应物和产物浓度随时间的变化关系以及反应的选择性和收率,得出了实验操作范围内适宜的催化剂组成、制备方法和反应工艺条件。 相似文献
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Synthesis of methylal by catalytic distillation 总被引:1,自引:0,他引:1
Methylal is an important raw material and an excellent solvent in industry. The conventional methods for the synthesis of methylal have drawbacks such as corrosion to the equipments, catalyst isolation, high molar ratio of methanol to formaldehyde and high cost of equipments. To overcome these drawbacks, the synthesis of methylal was investigated in a pilot scale catalytic distillation column using Sulzer BX and the structured catalytic packing Katapak-SP 12 in the present study. The reaction was catalyzed by polystyrene based macroporous cation exchange resin (D72) which was filled in the catalystic layers of the structured packings. The effects of operating parameters such as reflux ratio, total feed rate, molar ratio of methanol to formaldehyde, catalyst weight, aqueous formaldehyde concentration were studied experimentally. The appropriate operating parameters obtained in the present study include: reflux ratio is 5; total feed rate is 3.10 kg/h; molar ratio of methanol to formaldehyde is 2.5, catalyst weight is 0.51 kg, aqueous formaldehyde concentration is 35.3%. Under the above operating conditions the average conversion of formaldehyde is 99.6% while the average methylal purity is 92.1%. In order to achieve higher purity of methylal at the top of the column, two different configurations: feeding aqueous formaldehyde and feeding water at mid-way of rectifying section, was tried in the experiments. The experimental results show that the former configuration surpasses the latter, under which the average conversion of formaldehyde is 99.8% and the average methylal purity is 99.1%. 相似文献
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An integrated continuous process, which combines catalytic distillation and extractive distillation in one column, is investigated for the synthesis of high‐purity methylal from methanol and formalin in the presence of a cation‐exchange resin catalyst. A feed with methanol:formaldehyde 2:1 molar ratio is chosen to evaluate the effects of operating parameters, such as extractant feeding position, ratio of extractant to feed, reflux ratio, and reboiler temperature, on the continuous synthesis of methylal. Under the optimum operating conditions and with water as extractant, the extractive catalytic distillation process operated continuously, producing a methylal purity of 98.7 % (H2O: < 1.30 %) with 98.0 % formaldehyde conversion. 相似文献