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三氯氧钒——倍半烷基铝催化体系在聚合过程中催化活性随反应时间增加而下降,即活性中心随时间而减少,当对甲基苯磺酰氯加至反应混合物中后,催化效率可增6倍,对甲基苯磺酰氯的活化作用设想为由于将失活的催化剂中心再氧化成活泼的三价(或四价)的钒化合物。目前国内进行乙丙橡胶生产所采用的催化体系,均为三氯氧钒一倍半烷基铝体系。其主要问题是催化剂的活性随反应时间增加而剧烈下降,催化效率低,三元胶的生产中一般仅为300克—350克胶/克三氯氧钒。这样,既过多的消耗了钒的化合物,又增加了乙丙胶后处理的困难,造成胶中残余钒含量大,严重影响了乙丙胶的电性能及其它性能。为提高催化体系的催化效率,添加某种活化剂是行之有效的办法。有文献报导,国外在这方面已做了大量的工作,如添加顺酐、苯磺酰氯,β—β—双—三氯甲基—β—内酯为活化剂都可使催化效率提高5—7倍。国内的研究工作近来也有较大的进展,如添加三氯醋酸乙酯、苯磺酰氯、偶氮苯等活化剂的小试工作都已取得成绩,有的已进行了中试。鉴于对甲基苯磺酰氯比苯磺酰氯挥发性小、来源丰富(糖精生产的付产品)容易提纯,又不像偶氮苯那样会使乙丙胶的色泽加深,所以继偶氮苯的工作以后,我们又对对甲基苯磺酰氯的活化作用进行了试验。
Catalytic activity of vanadium oxychloride-sesquioaluminate polymerization system decreased with the increase of reaction time, that is, the activity center decreased with time. When p-toluenesulfonyl chloride was added to the reaction mixture, the catalytic efficiency Can be increased 6-fold. The activation of methylbenzenesulfonyl chloride is envisaged to be due to reoxidation of the deactivated catalyst center to a reactive trivalent (or tetravalent) vanadium compound. At present, the catalytic system adopted for the production of ethylene-propylene rubber in China is the half alkylaluminum trichloro vanadium system. The main problem is the activity of the catalyst decreases sharply with the increase of the reaction time, the catalytic efficiency is low, the production of ternary rubber is generally only 300 grams to 350 grams of glue per gram of vanadium oxychloride. In this way, too much consumption of vanadium compounds, but also increase the difficulty of post-processing ethylene-propylene rubber, resulting in a large residual vanadium content in the glue, seriously affecting the electrical properties of ethylene-propylene rubber and other properties. To improve the catalytic efficiency of the catalytic system, adding an activator is an effective way. It has been reported in the literature that a great deal of work has been done abroad in this area. For example, adding maleic anhydride, benzenesulfonyl chloride and β-β-bis-trichloromethyl-β-lactone as activators can increase the catalytic efficiency by 5- 7 times. In recent years, great progress has been made in domestic research work. For instance, small pilot projects such as adding ethyl trichloroacetate, benzenesulfonyl chloride, azobenzene and other activators have all made great achievements, and some have carried out pilot tests. Since p-methylbenzenesulfonyl chloride is less volatile than phenylsulfonyl chloride, it is easy to purify from sources rich in (the byproduct of saccharin production), unlike the azobenzene which causes the color of the ethylene-propylene rubber to deepen, so following the azobenzene work Later, we tested the activation of methylbenzenesulfonyl chloride.