Pervaporative dehydration of diethylene glycol through a hollow fiber membrane

In this study, the pervaporative dehydration of diethylene glycol (DEG) through a commercial hollow fiber membrane was investigated at various feed temperatures in the range of 333–363 K with feeds containing 0.5–2.0 wt % water. Unlike the usual pervaporative dehydration process in which water is less volatile than the organic solvent, the feed mixture used in this study contained the organic component DEG, which is less volatile than water, resulting in unique permeation behaviors. The permeation behaviors of the individual components were investigated as functions of the feed temperature and feed composition. In particular, the effect of the low vapor pressure characteristics of DEG was investigated. Semi‐empirical equations for predicting the individual component fluxes and separation factor were quantified directly from actual dehydration pervaporation of DEG. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

The reactions in the polyesterification of terephthalic acid with ethylene glycol

Conclusions 1. A closed-system analysis was carried out of the kinetics and process equilibrium of the formation of dimer 1 which is one of the basic products of the initial state of the poly-esterification reaction of terephthalic acid and ethylene glycol.2. It was established that the hydrolysis of dimer 1 proceeds along only one complexester bond and results in the formation of TPA and BHET.3. The kinetic parameters of the esterification reaction MHET + MHET and the thermodynamic characteristics of the reaction TPA + BHET were determined.4. The rate and equilibrium constants of the reactions MHET + BHET and TPA + MHET were calculated in the first approximation.All-Union Scientific-Research Institute for Synthetic Fibres. Translated from Khimicheskie Volokna, No. 1, pp. 17–20, January–February, 1976.     

气相色谱-质谱法测定牙膏中的二甘醇

利用毛细管柱气相色谱-质谱(GC-MS)测定牙膏中二甘醇的量,检出限为5 mg/kg,二甘醇的线性范围为5μg/mL~500μg/mL,回收率为95.2%~102.2%,相对标准偏差(RSD)为1.19%~1.54%。     

Effect of catalysts on the rate of esterification of terephthalic acid by ethylene glycol

Conclusions 1. The esterification of TPA by ethylene glycol is accelerated both by conventional catalysts of this process and by catalysts used for polycondensation of bis-(-hydroxyethyl)terephthalate (antimonic acid and organometallic compounds). The latter are more suitable for practical purposes because strong acids accelerate dehydration of ethylene glycol.2. Esterification of TPA by ethylene glycol in the presence of the investigated catalysts is a zero-order reaction up to the moment of complete dissolution of TPA (up to a degree of completion of the reaction equal to 89–91%).All-Union Scientific-Research Institute for Glass Fibre (VNIISV). Translated from Khimicheskie Volokna, No. 6, pp. 9–11, November–December, 1969.     

有机锡催化对苯二甲酸与新戊二醇反应动力学研究

本文通过实验模拟粉末涂料用聚酯树脂生产过程,研究了在所选温度范围(450.15-516.15 K)内,有机锡催化PTA与新戊二醇酯化反应,定义了羟基的质量摩尔浓度。实验数据表明以羟基的消耗速率表示的表观反应速率符合一级反应动力学方程,并求出反应动力学参数。     

Analysis of esterification mixtures of terephthalic acid and ethylene glycol by gel chromatography

A quantitative gel permeation chromatography analysis of polycondensation mixtures of terephthalic acid with ethylene glycol was carried out on a styrene-divinylbenzene copolymer (4% of crosslinking agent) using tetrahydrofuran as eluent. Adsorption effects on the gel were suppressed by addition of acetic acid. A calibration curve for the identification of linear and cyclic oligomers present in the reaction mixture is given.     

一缩二乙二醇二硬脂酸酯的合成

以一缩二乙二醇和硬脂酸为原料,进行酯化反应,合成医药缓释剂一缩二乙二醇二硬脂酸酯,考察了物料配比、反应时间、反应温度对产品纯度和收率的影响。结果表明,最佳工艺条件为:一缩二乙二醇∶硬脂酸=1∶2.2(摩尔比),反应时间4 h,反应温度140℃。该工艺可使产品的收率大于92%。     

工业PTA溶剂脱水过程动态模拟与分析

Dynamic model for dehydration process of industrial purified terephthalic acid solvent is investigated to understand and characterize the process.A temperature differential expression is presented,which ensures the equation to convergence and short computation time.The model is used to study the dynamic behavior of an azeotropic distillation column separating acetic acid and water using n-butyl acetate as the entrainer.Responses of the column to feed flow and aqueous reflux flow are simulated.The movement of temperature front is also simulated.The comparison between simulation and industrial values shows that the model and algorithm are effective.On the basis of simulation and analysis,control strategy,online optimization and so on can be implemented effectively in dehydration process of purified terephthalic acid solvent.     

气相色谱法测定市售牙膏中二甘醇的含量

采用毛细管气相色谱法,快速准确地测定了超市及集市中15种牙膏中二甘醇的含量。试样用无水硫酸钠除去水分,无水乙醇超声提取,FFAP毛细管柱分离分析,FID检测器进行了检测。二甘醇的标准曲线为Y=145.125+2 300.281X,线性范围为0.01~10 mg/mL,线性相关系数r=0.999 8,检出限为3.2μg/mL。实验证明,该方法适于牙膏等日用化学品中二甘醇含量的检测。     

Determination of diester formation in diethylene glycol and tetraethylene glycol monoesters

Polyethylene glycol monoesters on standing rearrange to form diesters. The formation of diester in monoester samples stored at 3 C, 25 C, and 37 C, respectively, for approximately 3 months was determined by reverse phase high performance liquid chromatography (HPLC) in less than one-half hour. Formation of diester increased with increasing storage temperature, regardless of the chemical nature of the     

二乙二醇甲基丁基醚的合成研究

在氮气保护下,以二乙二醇单甲醚(C5H12O3,DEGME)和正溴丁烷为(n-C4H9Br)原料,氢氧化钠为催化剂,苯为带水剂,通过Williamson反应合成了二乙二醇甲基丁基醚(DGBME);用正交实验法对合成条件进行了优化,气相色谱法分析了产品中DGBME的含量,FT-IR和1HNMR法表征了产物结构。结果表明,适宜的反应条件为:反应温度80℃,反应时间4 h,n(n-C4H9Br)∶n(DEGME)=1.06∶1,n(NaOH)∶n(DEGME)=1.5∶1.0;在此条件下,DGBME的收率可达92%以上。     

间苯二甲酸与二甘醇对PET共聚改性的研究

用间苯二甲酸 (PIA)、二甘醇 (DEG)作改性剂合成共聚酯 ,利用DSC分析加入 2 %～ 8% (mol)PIA对改性共聚酯的影响。结果表明 ,PIA作为第三组分、DEG作为第四组分参与共聚反应 ,合成的共聚酯的特性粘数下降 ,结晶速率减慢 ,结晶度降低 ,玻璃化温度和熔点均有所下降。DEG的添加量以 0 .5 % (质量分数 )为宜。     

二茂铁二羧酸双(二乙二醇)酯合成研究

以二茂铁、乙酰氯、溴、二乙二醇等为原料,合成出中间体二乙酰二茂铁、二茂铁二羧酸、二茂铁二羧酸二甲酯,再采用酯交换工艺,通过提高二乙二醇比例,选用低毒溶剂油,并利用甲醇/溶剂油易于分层、准确控制反应终点,合成出了高质量分数的目标产物二茂铁二羧酸双(二乙二醇)酯。该方法与直接酯化法相比收率提高至80%,目标产物质量分数为93%,相比酰氯法避免了使用剧毒的草酰氯、氯化亚砜,是低成本规模化制备目标产物的优化方法。     

Dehydration of diethylene glycol by pervaporation using HybSi ceramic membranes

The pervaporation dehydration of diethylene glycol using ceramic tubular membranes with a hydrophilic selective layer formed from HybSi material was experimentally studied. The experiments were carried out over the process temperature range of 70–90°C at pressures in the permeate part of membrane unit in the range of 5–30 mm Hg and at diethylene glycol concentrations in the range of 93.5–99.8 wt %. Dependences of the membrane surface area required for the dehydration of diethylene glycol over a predetermined range of concentrations on productivity, process temperature, and vacuum were determined.