碳酸二乙酯合成方法浅述

碳酸二乙酯是碳酸酯中的重要品种，有着广泛的用途。它用于许多有机合成，特别是用于合成医药和医药中间体，如何用于合成农药除虫菊酯和药物苯比妥的中间体。碳酸二乙酯还可作为溶剂，如可用于合成树脂、天然树脂、硝化纤维素、纤维素醚的溶剂和真空管阴极固定漆中。电子纯碳酸二乙酯可用于彩电显象管为清洁剂。碳酸二乙酯可用作表面活性剂和电池液添加剂等。     

酯交换法合成碳酸二乙酯工艺过程控制

介绍了碳酸二乙酯的用途及合成方法,重点阐述了以乙醇钠为催化剂,碳酸二甲酯和乙醇在一定的温度和压力下合成碳酸二乙酯的反应原理和工艺流程。从反应温度、压力、精馏方式、催化剂回收等方面对生产工艺过程控制进行了探讨,总结出一种效率高、成本低、质量好的碳酸二乙酯的生产工艺条件。     

酯交换合成碳酸二乙酯的反应精馏工艺研究

本文以乙醇和碳酸二甲酯为原料,甲醇钠为催化剂,对合成碳酸二乙酯的反应精馏工艺进行了研究,对其具体生产工艺及操作方式进行了详细的介绍,并对其进行了工业实验,取得了良好的实验数据;此外,为保证塔设备的可靠性,对三台精馏塔进行了流体力学核算,验证了设备的可行性。该内容为反应精馏方法合成碳酸二乙酯的相关模拟及大型化生产提供了技术参考,具有重要的实际意义。     

碳酸二乙酯非光气化合成研究

利用二(三氯甲基)碳酸酯作为光气替代物合成碳酸二乙酯。对反应温度、时间、物料配比、催化剂种类进行了考察,得出了最佳工艺条件。     

碳酸钾催化碳酸丙烯酯与乙醇酯交换合成碳酸二乙酯

采用半连续操作方式,对碳酸钾催化碳酸丙烯酯(PC)和乙醇酯交换合成碳酸二乙酯(DEC)反应进行了研究。碳酸钾对该反应有较好的催化活性,当催化剂用量为反应物质量的1.4%、乙醇与PC摩尔比为6、反应时间为5h、乙醇滴加速度为1.3mL·min-1时,PC转化率达95.2%,DEC选择性为84.9%。结合红外光谱分析结果推测了碳酸钾催化剂上PC与乙醇酯交换合成DEC的反应机理:K2CO3与乙醇反应生成CH3CH2OK和KHCO3,CH3CH2O-作为亲核试剂进攻PC羰基碳原子生成中间产物羟丙基乙基碳酸酯(HPEC),其他CH3CH2O-进一步进攻HPEC的羰基碳原子得到产物DEC,同时伴随着副产物1,2-丙二醇(PG)的生成以及KHCO3重新转化为K2CO3。     

碳酸二乙酯联产碳酸甲乙酯技术开发及产业化

阐述了碳酸二乙酯联产碳藏甲乙酯的工艺路线和开发过程，预测市场情况。     

碳酸二甲酯的合成方法及发展趋势

概述了碳酸二甲酯的合成方法和研究现状、以及合成技术中存在的问题,展望了碳酸二甲酯的发展趋势。     

碳酸二甲酯和乙醇酯交换合成碳酸二乙酯工艺研究

碳酸二乙酯分子结构中含有活性基团乙氧基和羰基,化学性质活泼,是一种重要的有机合成中间体、溶剂和性能优良的燃料添加剂,在化工领域具有很高的应用价值。以碳酸二甲酯和乙醇为原料,甲醇钠为催化剂,通过酯交换反应合成碳酸二乙酯。气相色谱分析表明,在酯与醇物质的量比1∶20、催化剂用量为碳酸二甲酯质量的1.0%、反应温度78 ℃和反应时间1 h条件下,碳酸二甲酯转化率达99%,碳酸二乙酯和碳酸甲乙酯选择性分别为86%和14%。     

常压气相羰基化合成碳酸二乙酯

用积分反应器在固定床连续流动反应体系中进行CO气相催化合成碳酸二乙酯。研究了以各种活性炭为载体的钯催化剂、催化剂浸渍方法和不同催化剂组成对合成碳酸二乙酯催化活性和选择性的影响 ,得到了有发展前景的催化剂。结果表明 ,以逐滴浸渍法 ,使用M3 为助催化剂 ,反应温度 1 0 5～ 1 2 0℃时 ,催化剂有较好的活性和选择性。     

碳酸二甲酯与碳酸二乙酯酯交换合成碳酸甲乙酯的研究

以Al2O3/SiO2为催化剂考察了碳酸二甲酯和碳酸二乙酯在液相条件下酯交换合成碳酸甲乙酯的过程.研究了活性组分负载量、催化剂用量、反应温度、反应时间等条件对酯交换反应的影响,并通过NH3-TPD和N2吸附脱附等手段对催化剂进行了表征.结果表明:以SiO2为载体,Al2O3负载量为12%的催化剂对碳酸二甲酯与碳酸二乙酯...     

替代光气进行有机合成的化学方法

综述了目前取代剧毒原料光气进行有机合战的12种有价值的绿色化学方法，以典型的合成路线为基础．介绍了其优缺点、发展现状及存在的问题，得出结论：碳酸二甲酯的方法是当前最为廉价且已有大规模生产的方法．三光气、碳酸乙烯酯取代光气也取得了一定的成绩，而一氧化碳羟基化有很好的前景．但需在催化剂方面作进一步研究。     

离子交换树脂催化合成丁二酸二乙酯

论述了以丁二酸,无水乙醇为原料,离子交换树脂,催化合成丁二酸二乙酯的新工艺。考察了催化剂种类,用量,原料配比,反应时间以及催化剂使用次数等因素对酯化率的影响,确定了催化剂种类和最佳工艺条件,结果表明HD－8强酸性离子交换树脂具有良好的催化活性和选择性,可多次重复使用,酯化率可达76．4％,产品质量符合国家标准。     

Experimental and Kinetic Studies on a Homogeneous System for Diethyl Carbonate Synthesis by Transesterification

A synthesis of diethyl carbonate through transesterification of propylene carbonate and ethanol, coproducing useful propylene glycol, was carried out in the presence of sodium ethoxide as catalyst. The effects of reaction parameters such as catalyst concentration, mole ratio of ethanol to propylene carbonate and reaction temperature on the transesterfication reaction were investigated. The results showed that the reaction is reversible with a propylene carbonate equilibrium conversion of about 64 % at an ethanol to propylene carbonate mole ratio of 8.0 and a reaction temperature of 303 K. A kinetic model was proposed based on the reaction mechanism. The model parameters were estimated by the Runge‐Kutta method. The statistical test showed that the model calculation results were in good agreement with the experimental data.     

高效液相色谱法测定马来酸二乙酯

论述了高效液相色谱法测定马来酸二乙酯含量的方法。本方法的标准偏差为0．24。变异系数为0．29％，平均回收率为100．1％。     

己二酸二乙酯合成新工艺的研究

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。     

氯化铁催化合成丁二酸二乙酯的研究

氯化铁作为了二酸和乙醇的酯化催化剂,性能优于硫酸。本文探讨并找到其较好的反应条件,酯化率达９０．４６％。     

Enhanced Conversion in the Direct Synthesis of Diethyl Carbonate from Ethanol and CO2 by Process Intensification

To overcome the low equilibrium conversion in the direct synthesis of diethyl carbonate from ethanol and CO₂ under moderate reaction conditions, the reaction was conducted in a membrane reactor packed with pelletized Cu‐Ni:3‐1 supported on activated carbon. A SiO₂/γ‐Al₂O₃ commercial membrane and zeolite A membranes synthesized on commercial Al₂O₃ supports were evaluated in the membrane reactor. Although characterization of the membranes by X‐ray diffraction confirmed the presence of a zeolite A layer on the supports, gas permeation and permselectivity tests of ethanol and water evidenced some defects of the synthesized membranes. An increase in conversion with respect to a conventional packed‐bed reactor was observed in the membrane reactors prepared on Al₂O₃, but equilibrium conversion was not attained. However, with the commercial membrane, the ethanol conversion was higher than the equilibrium conversion.     

无水氯化铁催化合成丁二酸二乙酯

报道了以丁二酸和无水乙醇为原料,在无水氯化铁催化下合成丁二酸二乙酯的反应条件。结果表明：在回流温度下,醇酸物质的量比为２．４：１,催化剂用量为０．０３ｍｏｌ．ｍｏｌ＾－１丁二酸时,反应３ｈ,丁二酸的转化率可达７２．４％。     

Towards a Phosgene-Free Synthesis of Aryl Isocyanates: Alcoholysis of <Emphasis Type="Italic">N-</Emphasis>phenylurea to <Emphasis Type="Italic">N-</Emphasis>phenyl-<Emphasis Type="Italic">O-</Emphasis>methyl Carbamate Promoted by Basic Metal Oxide Nanoparticles and Organocatalysts

There is an urgent need to develop new processes for the synthesis of polyurethanes and polycarbonates different from the current technology based on the use of phosgene. In the case of polyurethanes, the reaction of phosgene with aromatic amines renders N-aryl isocyanates that are the co-monomers for these polymers. In the search for a phosgene-free process for the synthesis of N-aryl isocyanates, N-aryl carbamates could play a key role of synthetic precursors. N-Aryl carbamates can be prepared in turn by alcoholysis of N-aryl ureas. Herein, we compare the catalytic activity of three homogeneous catalysts and four heterogeneous metal oxides for the methanolysis of N-phenylurea as a model probe for other aromatic ureas. In the present work we have carried out this reaction in the presence of KOH, 1,8-diaminonaphthalene (a protonic sponge), a dimeric phosphazene (strong, neutral soluble base) and nanometric ZnO, MgO, CaO and a mixed Mg/Al metal oxide derived from hydrotalcite calcination. Besides the target N-phenyl O-methyl carbamate, N-phenyl isocyanate and undesired aniline were also formed. It was observed that using KOH and diaminonaphthalene, aniline was formed preferentially with respect to the desired carbamate. In contrast, dimeric phosphazene forms the target N-phenyl O-methyl carbamate with 90% selectivity at 99% N-phenylurea conversion. In the case of the metal oxides, the best-performing solid catalyst was CaO that exhibits similar activity (99% N-phenylurea conversion) and carbamate selectivity (89%) as phosphazene. CaO performs as a truly heterogeneous catalyst and could be reused for a second run with only a 4 and 2% decrease in conversion and selectivity, respectively.