Separation of ethylene glycol, 1,2-butanediol and 1,2-propanediol with azeotropic distillation

1,2-butanediol (1,2-BDO) and 1,2-propanediol (1,2-PDO) are inevitably side produced in the ethylene glycol (EG) production processes from non-petroleum routes, but are very difficult to separate by the ordinary distillation method because of the closeness of their boiling temperatures to EG, thus compromise the economy of these processes. The azeotropic distillation process using 1-octanol (CPO) as an entrainer to separate EG and 1,2-BDO mixture with or without 1,2-PDO was studied in this paper. Four binary vapour–liquid equilibrium data of EG-1,2-BDO, EG-CPO, 1,2-BDO-CPO, and 1,2-PDO-CPO were measured using an Ellis equilibrium kettle and regressed with the thermodynamic model of non-random two liquid to obtain the corresponding binary interaction parameters. On this basis, azeotropic distillations with CPO as an entrainer were designed to separate EG and 1,2-BDO with or without 1,2-PDO. The complete separation processes, including the azeotropic distillation and CPO recovery process consisting of extraction with H₂O and subsequent distillation, were simulated and optimized with Aspen Plus for both the EG-1,2-BDO binary mixture and the EG-1,2-BDO-1,2-PDO ternary mixture. The simulation results show that the azeotropic distillation method with CPO as an entrainer can effectively separate the mixture of EG-1,2-BDO and EG-1,2-BDO-1,2-PDO, achieving EG of 99.90% purity with 99.98% recovery and 1,2-BDO of 99.30% purity with 99.45% recovery for the binary mixture, and achieving EG of 99.90% purity with 99.80% recovery, 1,2-BDO of 99.35% purity with 99.35% recovery, and 1,2-PDO of 90.59% purity with 94.38% recovery for the ternary mixture. These processes are promising for industrial application and can significantly improve the economy of non-petroleum EG production.     

缩聚催化剂乙二醇锑的应用

介绍了聚酯缩聚催化剂乙二醇锑在上海石化涤纶部的试用和推广应用过程 ,讲述了乙二醇锑的配制和添加的特点 ,对聚酯生产过程和对聚酯产品的影响 ,以及乙二醇锑的聚酯产品对纺丝后加工性能的影响。     

环氧乙烷/乙二醇生产技术现状及发展建议

简要介绍了环氧乙烷/乙二醇(简称EO/EG)的生产及技术现状,在对现有Shell、SD和UCC工艺进行比较的同时,探讨了EO/EG生产中银催化剂、乙烯回收技术及EG合成技术的进展和新工艺的工业化前景,认为催化水合法和碳酸乙烯酯法是目前最有前途的工业化方法。分析了我国EO/EG工业面临的主要问题,并提出了我国发展EO/EG工业的对策和建议。     

乙二醇-1,2-丁二醇二元体系汽液平衡数据的测定及关联

为解决合成气经由草酸酯制乙二醇反应过程中产生的副产物1,2-丁二醇与乙二醇的分离问题,利用改进的Ellis汽液平衡釜测定了乙二醇-1,2丁二醇二元体系常压下汽液平衡数据,并通过Herington规则验证了实验结果符合热力学一致性。分别用Wilson和NRTL模型对实验数据进行热力学关联,得到了相关的模型参数并计算了该二元体系不同摩尔分数2种组分的活度系数值,预测了该二元体系的共沸点组成(摩尔分数)为乙二醇47.0%,1,2-丁二醇53.0%,共沸点温度为465.91 K。汽相组成的计算值与实验值平均相对偏差均小于0.2%,说明2种模型均适用于该二元体系,为工业分离工艺的设计提供了参考。     

Hydrogenation of dimethyl oxalate to ethylene glycol over mesoporous Cu‐MCM‐41 catalysts

The synthesis and utilization of mesoporous Cu‐MCM‐41 catalysts for hydrogenation of dimethyl oxalate to ethylene glycol is described in this article. Physicochemical properties of these Cu‐MCM‐41 catalysts have been investigated by N₂‐physisorption, X‐ray diffraction, inductively coupled plasma, N₂O titration, transmission electron microscopy, temperature programmed reduction, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy. It was found that the copper loading significantly influenced the pore structure and copper surface area of the catalyst. High catalytic performance is obtained over a 20Cu‐MCM‐41 catalyst with a full DMO conversion and EG yield of 92% at a LHSV of 3.0 h^?1. The catalytic performance of optimized 20Cu‐MCM‐41 catalyst could be attributed to the fine copper dispersion and large copper surface areas. © 2013 American Institute of Chemical Engineers AIChE J, 59: 2530–2539, 2013     

CaY分子筛对乙二醇和1,2-丁二醇吸附分离性能的研究

利用装填有CaY分子筛的固定床对乙二醇和1,2-丁二醇吸附分离进行研究,从水、甲醇、乙醇和正丙醇中筛选出正丙醇为最佳洗脱溶剂,并探究了进样流速(0.4, 0.8, 1.2 mL/min)及操作温度(298, 318, 338 K)对穿透曲线的影响,对测得的穿透曲线采用Modified Dose-Response模型进行拟合,与实验结果能够高度吻合。并采用巨正则蒙特卡洛(GCMC)研究混合醇在CaY分子筛内部的竞争吸附,模拟了乙二醇和1,2-丁二醇在CaY分子筛内部的吸附位点,发现其吸附位点几乎重合,且CaY分子筛对乙二醇的吸附量要大于1,2-丁二醇,此模拟结果为实验结果提供了微观理论支撑。     

聚乙二醇/聚己内酯三嵌段共聚物的合成与表征

以甲苯二异氰酸酯 (TDI)为偶联剂 ,合成了聚乙二醇 (PEG) /聚己内酯 (PCL)两亲性三嵌段共聚物 (PEG-b-PCL -b -PEG ,PECL) ,采用IR、1 H-NMR、DSC和WAXD分析和研究了PECL的结构与性能。实验结果表明 ,PECL的结构和组成与设计相一致 ,结晶度和熔点均低于均聚物 ,且随着PECL中PCL嵌段含量的增加 ,PCL嵌段熔点升高。透射电镜照片显示PECL纳米粒呈核 /壳结构的球形。     

Selective removal of 1,2‐propanediol and 1,2‐butanediol from bio‐ethylene glycol by catalytic reaction

Ethylene glycol (EG), synthesized from biomass, frequently contains refractory 1,2‐propanediol (PDO) and 1,2‐butanediol (BDO). Selective removal of PDO and BDO was realized herein by catalytic dehydration to form volatile aldehydes, ketones, and acetals. Various acidic and basic catalysts were screened under a range of conditions for the conversion of a mixture containing 73 wt % EG, 20 wt % PDO, and 7 wt % BDO. Over H‐Beta 26 zeolite, the most selective catalyst among tested, PDO and BDO conversions reached 99.1 and 99.3%, respectively, after 4 h reaction at 453 K, with separation factors over 2. The activation energies for EG, PDO, and BDO dehydration were ca. 99.3, 69.9, and 54.0 kJ/mol, respectively, accounting for the high reactivity of PDO and BDO. The dehydration largely proceeded in the micropores of H‐Beta and depended on the number of strong Brønsted acid sites, but excessively strong acid sites enhanced the polymerization of EG. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4032–4042, 2017     

我国乙二醇的生产与需求

我国近年来乙二醇生产发展迅速，但仍满足不了国内迅速增长的需求．１９９４年我国乙二醇的产量达３８．９９万ｔ，需求量为５１．３３万ｔ。预计１９９６年国内总需求量约为６０万ｔ。     

A型分子筛膜在分离乙二醇水溶液中的应用

采用抽空涂晶二次生长法成功地合成出了A型分子筛膜,研究了乙二醇水溶液在A型分子筛膜上的渗透气化和蒸气渗透分离性能,考察了温度、浓度对渗透通量的影响,完成了1000 h的稳定性实验。结果表明,A型分子筛膜对EG水溶液具有非常高的分离选择性和稳定性,分离系数达到10000,在120 ℃透量达到10 kg/(m2•h)。     

煤制乙二醇产业现状

乙二醇是一种重要的有机化工原料,主要以石油为原料进行生产。中国特殊的能源结构使煤制乙二醇研究热度日益高涨。阐述了3种煤制乙二醇工艺路线及优缺点,详细介绍了CO催化偶联法制乙二醇生产技术。通过分析国内乙二醇的供需形势、投资建设情况,认为煤制乙二醇拥有成本优势,具有一定的竞争力,但不可盲目开发投资,谨防产能过剩,且仍需开拓下游产品,拓宽利用途径,抵抗市场风险。     

石油与煤路线制乙二醇过程的技术经济分析

传统石油制乙二醇(OtEG)路线严重依赖于石油资源且生产成本高,而我国拥有丰富的煤炭资源,使得煤制乙二醇(CtEG)技术日益受到重视。基于全流程模拟结果,对OtEG和CtEG路线进行了详细的技术经济分析。结果表明,CtEG路线单位产品的能耗比OtEG高2.62 t-ce标准煤;但CtEG具有较好的成本优势,约可节省成本802 CNY·t^-1,但其总投资约为OtEG的2.58倍。适当扩大生产规模可明显提高OtEG和CtEG工艺的经济效益,尤其是降低CtEG的总投资。通过分析原料价格波动对两条路线竞争力的影响发现,当油价低于40 USD·bbl^-1(美元/桶),且煤价高于500 CNY·t^-1时,CtEG与OtEG的生产成本比将高于1.0;当油价高于60 USD·bbl^-1,即使煤价高达850 CNY·t^-1,生产成本比也将低于1.0。此外,CtEG的CO₂排放量和水耗分别比OtEG高约5 t·t^-1和20 t·t^-1     

Biodegradability of poly(ethylene terephthalate) copolymers with poly(ethylene glycol)s and poly(tetramethylene glycol)

Poly(ethylene terephthalate) copolymers were prepared by melt polycondensation of dimethyl terephthalate and excess ethylene glycol with 10–40mol% (in feed) of poly(ethylene glycol) (E) and poly(tetramethylene glycol) (B), with molecular weight (MW) of E and B 200–7500 and 1000, respectively. The reduced specific viscosity of copolymers increased with increasing MW and content of polyglycol comonomer. The temperature of melting (T_m), cold crystallization and glass transition (T_g) decreased with the copolymerization. T_m depression of copolymers suggested that the E series copolymers are the block type at higher content of the comonomer. T_g was decreased below room temperature by the copolymerization, which affected the crystallinity and the density of copolymer films. Water absorption increased with increasing content of comonomer, and the increase was much higher for E1000 series films than B1000 series films. The biodegradability was estimated by weight loss of copolymer films in buffer solution with and without a lipase at 37°C. The weight loss was enhanced a little by the presence of a lipase, and increased abruptly at higher comonomer content, which was correlated to the water absorption and the concentration of ester linkages between PET and PEG segments. The weight loss of B series films was much lower than that of E series films. The abrupt increase of the weight loss by alkaline hydrolysis is almost consistent with that by biodegradation.     

试用国产乙二醇锑的实践与启示

阐述了在PET缩聚反应中试用乙二醇锑的情况和产品对纺丝性能的影响。指出与Sb2 O3相比 ,乙二醇锑的添加液配制温度低 ,省时 ,带入杂质少 ,二者催化效能等同 ,但新型催化剂售价贵 ,用量多。纺丝及后加工性能有所改善。     

聚乙二醇单甲醚接枝壳聚糖的合成与表征

通过官能团偶联反应,将端基改性为醛基的聚乙二醇单甲醚(mPEG)按一定配比,在适宜条件下与壳聚糖(CS)反应,制得了梳状的可溶于水的聚乙二醇单甲醚接枝壳聚糖(mPEG g CS)。采用元素分析、红外光谱和透射电镜等方法对产物的结构和性质进行表征。研究表明,所制得的mPEG g CS在水溶液中能够自组装成胶束,并表现出有别于壳聚糖的流变性。     

乙二醇消耗分析及降低途径的探讨

通过对聚酯装置 (DMT法 )乙二醇消耗的理论值、设计值和实际情况的分析 ,确定影响乙二醇单耗的主要因素并探讨降低乙二醇单耗的有效途径。     

草酸酯法由合成气制备乙二醇技术研究进展

介绍了以合成气作为原料由草酸酯法合成乙二醇路线的国内外技术研究概况,分别对草酸酯合成和加氢反应两个部分的催化剂研究和工艺应用状况进行了阐述,并指出了草酸酯合成法工业化应用的潜力。     

草酸二乙酯加氢制乙二醇产品精馏试验研究

通过减压间歇精馏对草酸二乙酯加氢制乙二醇产品进行精制.试验表明该方法切实可行,获得了纯度≥99.8％的乙二醇产品;同时探讨了塔顶压强、回流比变化对产品纯度的影响,获得了试验条件下的最佳操作条件,为工业化提纯草酸二乙酯加氢制乙二醇产品提供了有益信息.     

新型催化剂乙二醇锑的试用

介绍乙二醇锑溶液的配制及试用情况。结果表明溶液配制简化,可提高缩聚能力,减少引进杂质,L值、b值均有较大改善,提高满卷率和一等品率,延长过滤器寿命。PET切片成本增加8元/t。