A novel route to synthesis of glycerol dimethyl ether from epichlorohydrin with high selectivity

The effective utilization of glycerol, a by-product in the production of biodiesel, into useful chemicals is desirable from the viewpoint of green chemistry. With this in mind, a novel and highly selective route to synthesizing glycerol dimethyl ether (2,3-dimethoxy-1-propanol), a potential fuel additive, from glycerol was proposed. This route uses both glycerol and methanol as starting materials, takes epichlorohydrin as an intermediate product, and utilizes HCl as a recycling agent. Hereinto, the key step of this route is the reaction between epichlorohydrin and methanol to produce 2,3-dimethoxy-1-propanol which is identified by GC–MS, ESI-MS, IR and NMR. The thermodynamics of this reaction was analyzed and the result showed that the thermodynamics of a reaction was favorable and a high product yield was expected. The effect of various parameters such as kind of acid catalyst, molar ratio of epichlorohydrin to methanol, reaction temperature and reaction time was studied. Among various acid catalysts investigated, the acidic ionic liquid [HSO₃-b-N(CH₃)₃]HSO₄ exhibited the highest activity and selectivity: conversion of epichlorohydrin of 100% and selectivity of 2,3-dimethoxy-1-propanol of 99% at 393 K, 10 h, an initial pressure of 0.1 MPa and a molar ratio of catalyst:ECH:CH₃OH of 0.01:1:5. After the reaction, [HSO₃-b-N(CH₃)₃]HSO₄ was separated by vacuum distillation and then reused for the next cycle directly. The results showed that the product selectivity remained at about 94% but the conversion of epichlorohydrin dropped to 75% after being used five times. Subsequently, a reaction mechanism for the synthesis of 2,3-dimethoxy-1-propanol from epichlorohydrin and methanol was proposed.     

O-甲基丙烯酰-氧乙基二甲基环氧丙基氯化铵的合成与表征

以甲基丙烯酸二甲氨基乙酯(DM)和环氧氯丙烷(ECH)为主要原料,合成了一种活性体O-甲基丙烯酰-氧乙基二甲基环氧丙基氯化铵(ODEAC)。采用单因素实验分别讨论了反应溶剂、反应温度、物料比及反应时间对产物的转化率和环氧值的影响,确定了最佳合成工艺为:反应温度60℃,反应溶剂为异丙醇,物料比n(ECH)∶n(DM)=1∶1.6,反应时间4 h,在该条件下目标产物的转化率可达91.67%。并采用傅里叶变换红外光谱仪(FTIR)和核磁共振波谱仪(1HNMR)对产物结构进行了表征。     

Evaluation of an improved epichlorohydrin synthesis from dichloropropanol using a microchemical system

Synthesizing epichlorohydrin (ECH) from dichloropropanol (DCP) is a complicated reaction due to the partial decomposition of ECH under harsh conditions. A microchemical system can provide a feasible platform for improving this process by conducting a separation once full conversion has been achieved. In this work, referring to a common DCP feed used in industry, the reaction performance of mixed DCP isomers with NaOH in the microchemical system on various time scales was investigated. The operating window for achieving high conver-sion and selectivity was on a time scale of seconds, while the side reactions normal y occurred on a time scale of minutes. Plenty of Cl?ions together with a high temperature were proved to be critical factors for ECH hydrolysis. A kinetic study of alkaline mediated ECH hydrolysis was performed and the requirements for an improved ECH synthesis were proposed by combining quantitative analysis using a simplified reaction model with experimen-tal results on the time scale of minutes. Compared with the conventional distillation process, this new strategy for ECH synthesis exploited microchemical system and decoupled the reaction and separation with potentials of higher productivity and better reliability in scaling up.     

环氧氯丙烷的生产工艺与改进

介绍了环氧氯丙烷的生产及工艺改进的方法。     

环氧氯丙烷的市场分析

本文分析了国内外环氧氯丙烷的生产和消费情况，提出了发展我国环氧氯丙皖生产的一些建议。     

Fenton试剂氧化处理环氧氯丙烷废水的探索

环氧氯丙烷废水毒性强、生物降解性差,不适合用一般的生物方法处理,提出Fenton试剂氧化处理的方法.实验撂索了Fenton试剂反应的影响因素以及条件,发现当废水初始pH为3,H2O2的投加量是1.92 g/L,ρ(Fe2+)=1.60 g/L,即m(H2O2):m(Fe2+)=1.2,Fe2+等量分两次投加,总反应时间为1 h时,COD去除率可达89.44%.药剂分次投加比一次投加对处理效果有很大的提高.     

国内外环氧氯丙烷生产技术和市场发展趋势的研究

详实地分析了国内外环氧氯丙烷生产技术、市场消费趋势的变化。提出了通过加强国内新工艺技术的研究、引进装置扩大规模来保障环氧氯丙烷下游产品消费。通过绿色化工理念，解决现工艺中存在的“三废”污染治理，从而增强国内环氧氯丙烷生产企业的国际竞争能力。     

Synthesis and enzymatic degradation of epichlorohydrin cross-linked pectins

The water solubility of pectin was successfully decreased by cross-linking with increasing amounts of epichlorohydrin in the reaction media. The initial molar ratios of epichlorohydrin/ galacturonic acid monomer in the reaction mixtures were 0, 0.37, 0.56, 0.74, 1.00, 1.47, and 2.44. The resulting epichlorohydrin cross-linked pectins were thus referred to as C-LP0, C-LP37, C-LP56, C-LP75, C-LP100, C-LP150, and C-LP250, respectively. Methoxylation degrees ranged from 60.5 ± 0.9% to 68.0 ± 0.6%, and the effective cross-linking degrees, determined by quantification of the hydroxyl anions consumed during the reaction, were 0, 17.8, 26.0, 38.3, 46.5, 53.5, and 58.7%, respectively. After incubating the different cross-linked pectins (0.5% w/v) in 25 mL of 0.05 M acetate-phosphate buffer (pH 4.5), containing 50 µL of Pectinex® Ultra SP-L (pectinolytic enzymes), between 60 and 80% of the pectin osidic bounds were broken in less than 1 hr. Moreover, increasing the cross-linking degree only resulted in a weak slowing on the enzymatic degradation velocity.     

蒸发与Fenton试剂联用处理环氧氯丙烷废水的研究

针对环氧氯丙烷废水含盐量高、难降解等特点,采用蒸发-Fenton试剂氧化法联合对环氧氯丙烷废水进行处理,考察了pH值、H2O2投加量、Fe2+投加量、反应时间、反应温度等因素对CODCr去除率的影响。结果表明,当pH值为3.0、H2O2浓度为2.50 g/L、Fe2+浓度为1.84 g/L、反应时间为60 min、反应温度为60℃时,废水CODCr去除率可达90.4%。     

Degradation and Stabilization of Epichlorohydrin Elastomers

Abstract

Thermo-oxidative destruction of epichlorohydrin elastomers by methods of IR- and ESR-spectroscopy. Variation of physico-mechanical properties has been also studied. Antioxidants are proposed for these polymers. The mechanism of oxidation is discussed.