共查询到20条相似文献,搜索用时 593 毫秒
1.
2.
3.
简述了近年来碳酸二酯合成方法的研究进展,介绍了酯交换法、氧化羰化法、脱羰基法和二氧化碳直接合成法等,并着重介绍了碳酸二甲酯、碳酸二乙酯、碳酸二苯酯合成工艺中催化剂的研究与开发情况。 相似文献
4.
刘宝生 《化学推进剂与高分子材料》1998,(5):11-13
介绍了酯交换法、甲醇氧化羰化法生产碳酸二甲酯的原理、工艺路线及研究进展。对甲醇气相氧化羰化工艺进行评述,并与液相氧化羰基化法工艺对比,分析预测其发展前景。 相似文献
5.
综述了近年来酯交换法、苯酚氧化羰化法、草酸二甲酯和苯酚交换、脱羰法和尿素酚解法4种非光气法催化合成碳酸二苯酯(DPC)的研究进展,包括每种合成法所使用的催化剂、反应条件、反应物的转化率和产物的收率,指出了每种合成法的优缺点,并从原料来源的难易、催化剂制备的成本、产物的收率、生产工艺的复杂性、能耗等方面进行分析比较,指出选用酯交换法和尿素酚解法生产碳酸二苯酯较为有利,这两种合成法可能是未来研究的重点。 相似文献
6.
评述了4种非光气法合成碳酸二苯酯的新工艺,包括草酸二甲酯与苯酚酯交换法、碳酸二甲酯与乙酸苯醑酯交换法、尿素酯化法以及二硫化碳合成法.重点讨论了催化剂和工艺条件对合成碳酸二苯酯的影响.同时还介绍了3种偶联新工艺,即氧化羰化合成草酸二甲酯和草酸二甲酯与苯酚酯交换相结合的偶联新工艺、尿素醇解与碳酸二烷基酯与苯酚酯交换偶联的新工艺、乙酸甲酯高温裂解与碳酸二甲酯与乙酸苯酯酯交换相结合的新工艺.这些偶联工艺均考虑了各种副产物的循环使用,原料的利用率高、操作费用较低、有较强的竞争力. 相似文献
7.
碳酸甲乙酯(EMC)是一种环境友好型的不对称碳酸酯,因其独特的结构性质被广泛用作溶剂或有机合成中间体,特别是随着锂离子电池的迅猛发展,其作为电池电解液主要成分市场需求量急增。文中简单介绍了光气法、氧化羰化法和酯交换法合成碳酸甲乙酯的研究进展。重点针对最具发展前景的酯交换法合成EMC工艺路线中所用催化剂进行了综述;讨论和分析了该路线所用催化剂的类型、结构、性质及性能,并对当前研究中存在的问题进行了归纳和分析总结。最后本文分析并展望了酯交换法合成EMC催化剂的研究方向及新型合成工艺发展趋势,提出研发经济、高效、稳定且制备工艺简单的非均相催化剂,并与反应精馏技术耦合是今后的主要发展趋势,期望为EMC的高效合成提供参考和借鉴。 相似文献
8.
9.
10.
碳酸二苯酯的合成及分离提纯工艺进展 总被引:1,自引:1,他引:0
对碳酸二苯酯的合成、分离提纯工艺进行了综述.重点介绍了光气法、酯交换法、氧化羰化法、尿素法合成工艺,并对前三种工艺合成的碳酸二苯酯分离提纯作了重点介绍,对今后的发展趋势作了展望. 相似文献
11.
《Applied Catalysis A: General》2007,316(1):1-21
Diphenyl carbonate (DPC) is considered as a substitution for phosgene to synthesize polycarbonate resins. Conventional production of DPC involves reactions of phosgene and phenol. However, the phosgene process has drawbacks such as environmental and safety problems associated with using highly toxic phosgene as the reagent, which results in the formation of chlorine salts, and copious amounts of methylene chloride as the solvent. For these reasons, environmentally friendly processes for DPC production without using phosgene have been proposed and developed in the past decades. So far, the most promising alternatives appear to be the transesterification of dimethyl carbonate (DMC) and phenol, the direct oxidative carbonylation of phenol, and transesterification of dialkyl oxalates and phenol. This paper attempts to review recent literature concerning process design and catalytic chemistry for these phosgene-free approaches. The advantages and disadvantages are discussed for each reaction. Strategies to overcome potential problems are provided. The perspectives to improve catalytic efficiency of phosgene-free process are proposed. 相似文献
12.
Synthesis and characterization of a PAMAM dendrimer‐based superplasticizer and its effect on the properties in cementitious system 下载免费PDF全文
In this work, a polyamidoamine dendrimer‐based polycarboxylic superplasticizer (DPC) with a crosslinked emanative structure was synthesized via simple free radical polymerization. 1H‐nuclear magnetic resonance and Fourier transform infrared spectroscopy measurements were used for structural characterization. The fluidity, rheology behavior, and compressive strength of the cement/DPC samples were investigated in detail. The DPCs performed better dispersion and dispersion maintaining capabilities, stronger water reduction capability, and higher adsorption amounts than the conventional comb‐shaped superplasticizer. The dispersive capacity of the DPC increased with an increasing generation of polyamidoamine dendrimers. Besides, compared with conventional comb‐shaped superplasticizer, the addition of DPC led to a delayed and lowered heat flow peak on the hydration of cement paste at early age of hydration process. Furthermore, compressive strength results showed that the cement/DPC samples performed higher compressive strength than blank cement samples. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46550. 相似文献
13.
Multimode is the characteristic of industrial manufacturing processes due to different production strategies and environments. For multimode process monitoring, it is a challenge to identify different steady modes and transition modes. In this paper, a k nearest neighbours (KNN)-based density peaks clustering (DPC) method is applied to identify different modes. First, the local density of each sample, which is obtained with a KNN constraint and its minimum distance to the higher local density points are calculated as two indicators of the DPC algorithm to find the cluster centres of the training data. Then, the transition modes are identified by combining the moving window strategy and the DPC algorithm, where an index called the local density-distance ratio (LDDR) is employed. Finally, the monitoring algorithm is used to detect the faults for each operation mode. The effectiveness and advantages of the proposed method are illustrated by a numerical example and a Tennessee Eastman (TE) benchmark process. 相似文献
14.
15.
酯交换缩聚法合成聚碳酸酯的研究进展 总被引:2,自引:0,他引:2
聚碳酸酯的酯交换缩聚工艺具有绿色环保的特性,符合当今世界可持续发展的主题,相对于传统的光气法工艺更具有发展前途。综述了国内外在酯交换缩聚工艺的机理以及催化剂选择和工艺条件上取得的进展。指出碳酸二苯酯与双酚A酯交换反应是四面体机理,正反应是二级反应,逆反应是三级反应;以La(ACAC)_3作催化剂,得到的产品不但粘均分子量较高,而且热稳定性非常好;利用酯交换熔融聚合工艺可以解决传统光气法的环境问题,而固相聚合可以得到超高分子量的产品。 相似文献
16.
17.
18.
19.
探讨了大型生物法燃料乙醇项目副产二氧化碳的有效利用途径,提出了利用二氧化碳生产碳酸二甲酯(DMC),再利用DMC生产碳酸二苯酯(DPC),最后利用DPC生产聚碳酸酯的技术路线,从而使二氧化碳作为原料广泛地应用于有机合成,医药,化工,塑料等行业。 相似文献
20.
重结晶提纯碳酸二苯酯的溶剂选择 总被引:1,自引:0,他引:1
为了寻找重结晶法提纯碳酸二苯酯(DPC)的适宜溶剂,文章对DPC重结晶溶剂的选择及影响DPC纯度的因素进行了研究。结果表明:乙醇是重结晶纯化DPC的适宜溶剂,DPC在乙醇中溶解度在5—15℃的区间内变化缓慢,重结晶中止温度在15℃左右,DPC的收率高于89.0%。乙醇和DPC比率(质量比)采用8∶5为重结晶DPC时的适宜比率。通过对重结晶溶剂的进一步研究,发现采用水-乙醇的混合溶剂作为重结晶溶剂时,可以明显提高DPC的收率。水的质量分数在25.0%—35.0%范围内时,DPC的收率大于93.0%,纯度高于99.6%。其纯度符合合成聚碳酸酯的要求。 相似文献