一水硫酸氢钠催化合成乙二醇单甲醚乙酸酯

以一水硫酸氢钠为催化剂,由乙二醇单甲醚和冰乙酸合成了乙二醇单甲醚乙酸酯。考察了乙二醇单甲醚和冰乙酸摩尔比及催化剂用量对酯化率的影响。适宜反应条件为:乙二醇单甲醚∶冰乙酸∶一水硫酸氢钠=1∶1.75∶0.036(摩尔比),苯作带水剂,回流分水60min,酯化率达90.0%。产品经元素分析和红外光谱表征。     

固体超强酸S_2O_8~(2-)/Fe_2O_3—CoO催化合成乙酸异戊酯

制备固体超强酸催化剂S2O82-/Fe2O3—CoO,并用于乙酸异戊酯合成反应。用该催化剂通过正交试验合成乙酸异戊酯的最佳条件为:醇酸物质的量比为1.5,催化剂用量为0.8 g(以0.2 mol乙酸为准),带水剂用量为10 mL,反应时间为2.5 h,其酯化率可达98%以上。     

无机物——聚醋酸乙烯复合乳液粒子结构及主要性能

本文对均聚醋酸乙烯乳液及其与无机物的混合物,无机物——聚醋酸乙烯复合乳液的粒子结构进行了比较,阐述了复合乳液的主要性能。     

Catalytic hydrogenation of nitrile rubber using palladium and ruthenium complexes

The catalytic hydrogenation of acrylonitrile‐butadiene copolymer (nitrile rubber, NBR) using Pd(OAc)₂ or RuCl₂(PPh₃)₃ catalysts has been investigated in order to produce a totally saturated nitrile rubber. The hydrogenation of NBR is effective with both catalysts and achieved total conversion under the appropriate reaction conditions. In the case of palladium the effects of reaction parameters such as reaction temperature, pressure, time, catalyst concentration, and NBR concentration have been investigated. Even though both ruthenium‐ and palladium‐based catalysts are effective in the production of HNBR, the former requires harsh reaction conditions and has the drawback of gel formation under high conversion, motivating the migration to RuCl₂ (PPh₃)₃ as an alternative catalyst. The degree of hydrogenation was determined by IR and NMR spectroscopy. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007     

采用变压精馏回收共沸剂的正丙醇-水共沸精馏模拟研究

本文研究了一种分离正丙醇-水的新型共沸精馏工艺,通过变压精馏的方法对夹带剂乙酸乙酯进行回收。本研究采用Aspen—Plus软件中的RADFRAC精馏模块,以NRTL活度系数方程和Hayden-O'connell逸度方程为热力学模型对本工艺流程进行模拟,讨论了塔板数、进料位置、进料量、回流比和进料温度等参数对产物精馏和共沸剂回收的分离效果的影响,优化得出最佳工艺参数。结果表明,当精馏塔的塔板数为40块,进料位置为34板,回流比为8,夹带剂与进料比为0.9:常压回收塔的塔板数为20块,进料位置为4板,回流比为0.1,减压回收塔和常压回收塔的压力分别设定为0.2 aim和1 atm时,产物正丙醇的纯度为99.22 mol%,回收的共沸剂纯度达到99.87 mo1%,本文对正丙醇的工业生产具有一定指导意义。     

Thermal decomposition behavior of γ‐irradiated poly(vinyl acetate)/poly(methyl methacrylate) miscible blends

Miscible polymer blends based on various ratios of poly(vinyl acetate) (PVAc) and poly(methyl methacrylate) (PMMA) were prepared in film form by the solution casting technique using benzene as a common solvent. The thermal decomposition behavior of these blends and their individual homopolymers before and after γ‐irradiation at various doses (50–250 kGy) was investigated. The thermogravimetric analysis technique was utilized to determine the temperatures at which the maximum value of the rate of reaction (T_max) occurs and the kinetic parameters of the thermal decomposition. The rate of reaction curves of the individual homopolymers or their blends before or after γ‐ irradiation displayed similar trends in which the T_max corresponding to all polymers was found to exist in the same position but with different values. These findings and the visual observations of the blend solutions and the transparency of the films gave support to the complete miscibility of these blends. Three transitions were observed along the reaction rate versus temperature curves; the first was around 100–200°C with no defined T_max, which may arise from the evaporation of the solvent. The second T_max was in the 340–380°C range, which depended on the polymer blend and the γ‐irradiation condition. A third transition was seen in the rate of reaction curves only for pure PVAc and its blends with PMMA with ratios up to 50%, regardless of γ‐ irradiation. We concluded that γ‐irradiation improved the thermal stability of PVAc/PMMA blends, even though the PMMA polymer was degradable by γ irradiation. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 99: 1773–1780, 2006     

PE-LLD／EVA／Mg（OH）2／复合阻燃剂高效无卤阻燃体系的研究

采用线形低密度聚乙烯/乙烯-醋酸乙烯共聚物作为复合材料主体,表面处理过的氢氧化镁(Mg(OH)2)为主阻燃剂,以微胶囊化红磷和自制硅类阻燃剂为核心的复合阻燃剂为阻燃增效剂,重点探讨了Mg(OH)2和复合阻燃剂的阻燃效果。结果表明,Mg(OH)2与复合阻燃剂并用具有良好的协同效应,当Mg(OH)2用量40份,复合阻燃剂5～7份时,可获得较高的氧指数,垂直燃烧试验通过FV0级,且材料抗静电能力提高,力学性能、加工性能较好。     

Structural significance of the alkyl substituent at the C-4 of (+)-trans-verbenyl acetate in sex pheromonal activity of the American cockroach

The significance of the alkyl group at the C-4 of (+)-trans-verbenyl acetate, which is the sex pheromone mimic of the American cockroach, was investigated. Seven alcohols possessing an ethyl, propyl, or dimethyl group at this position of the 6,6-dimethylbicyclo[3.1.1]heptane skeleton were synthesized and evaluated by behavioral assay. All of the alcohols were inactive, while three of four acetates of the 2-alcohols induced sexual behavior in male cockroaches at the 0.02 or 0.5 mg dosage level, either of which is many orders of magnitude higher than the threshold level of the natural sex pheromones (10^–8 mg). Among the acetates, the compounds with a methyl group or an -oriented ethyl group at C-4 showed the highest activity. The results are discussed in terms of spatial requirements of the molecules for interactions with the receptor.Studies on the sex pheromone mimic of the American cockroach, (+)-trans-verbenyl acetate. Part VIII. For Part VII, seeComp. Biochem. Physiol.,70A: 229–234 (1981).     

Design and control of reactive distillation for ethyl and isopropyl acetates production with azeotropic feeds

Reactive distillations for the production of ethyl acetate (EtAc) and isopropyl acetate (IPAc) are classified as the type-II process where the first column consists of a reactive zone and a rectifying section followed by a stripper [Tang et al., 2005. Design of reactive distillations for acetic acid esterification with different alcohols. A.I.Ch.E. Journal 51, 1683-1699]. Instead of using pure alcohols and acetic acid as reactants, this paper studies the effects of reactant purity on the design and control of reactive distillation. This offers significant economical incentives (by reducing raw materials costs), because ethanol forms an azeotrope with water at 90 mol% and isopropanol/water has an azeotrope at 68%. The purities of the acid is set to 95% for acetic acid (industrial grade), 87% for ethanol, and 65% for isopropanol. The results show that the total annual costs (TAC) increase by a factor of 5% for EtAc and 8% for IPAc production using reactive distillation. Next, the operability of the reactive distillations with azeotrope feeds is explored. Three disturbances, feed flow, acid feed purity, and alcohol feed composition, are introduced to assess control performance using dual-temperature control and one-temperature-one-composition control. Simulation results indicate good control performance can be achieved for reactive distillation with azeotropic feeds.     

聚醋酸乙烯酯树脂聚合度的快捷检测方法

通过实验得出不同聚合度、不同质量分数下的黏度数据，并作出平均聚合度-质量分数-黏度三者的关系曲线。在此基础上，提出通过检测聚醋酸乙烯酯树脂的质量分数和黏度，直接查出对应的聚合度的快速检测方法。