【作者】 冯荣秀；

【导师】 宋健；

【作者基本信息】 天津大学 ， 应用化学， 2003， 硕士

【摘要】 本文以山梨醇为原料,在酸催化剂作用下,分别与对甲基苯甲醛或3,4-二甲基苯甲醛反应,制备了(1,3:2,4)-二(对甲基二苄叉)山梨醇(成核剂MDBS)和(1,3:2,4)-二(3,4-二甲基二苄叉)山梨醇(成核剂DMDBS)。工艺经过优化,收率达到99%,超过文献报道水平并实现了工业化生产,产品应用性能达到国外同类产品水平。对于甲苯-甲醇体系合成成核剂MDBS工艺来说,适宜的酸催化剂为十二烷基苯磺酸,甲苯比环己烷更有利于产品从凝胶态向粉末态的转化,补加甲苯-甲醇混合溶剂可以大大提高反应收率,较慢的反应分液速度对于反应有利。对甲基苯甲醛与山梨醇的摩尔比为2.3:1。反应中DMF、DMSO的存在对于反应不利。对于中和及后处理方式的研究表明:在产品中和、水洗后,采用甲苯、甲醇、环己烷、丙酮、反应前馏分等溶剂对产品进行热萃取可以纯化产品;后处理过程中适量水的存在对于产品质量没有影响;后处理中添加硬脂酸盐、叔胺及不同种类抗氧剂等可以不同程度提高产品性能,单长碳链叔胺的使用效果最佳。经处理产品熔点可高于250℃,工业化收率达到90%以上。对于成核剂DMDBS的合成工艺来说,适宜的酸催化剂为十二烷基苯磺酸,适宜的反应溶剂为环己烷-甲醇体系,3,4-二甲基苯甲醛与山梨醇的摩尔比为2.1~2.3。采用一次性加山梨醇然后分批加醛的加料方式,有助于成核剂从凝胶态向粉末态的转化。反应后期补加甲醇及维持高温反应一段时间,有利于成核剂的凝胶转化,提高反应收率,小试反应收率可以达到99%。中和及后处理时叔胺的甲苯溶液是最有效的后处理用溶剂,经处理可显著提高熔点,产品熔点可达261℃,产品工业化收率达到95%以上,质量达到国外同类产品水平,优于国内同类水平。对本方法进行工业化所合成的成核剂MDBS和成核剂DMDBS产品进行注塑工艺及造粒工艺应用试验,并与国外同类产品进行对比,其测试结果表明,本方法所合成的成核剂MDBS与DMDBS应用性能达到国外同类产品水平。更多还原

【Abstract】 (1,3:2,4)-di-(p-methylbenzylidene)sorbitol(MDBS) and (1,3:2,4)-di- (3,4-dimethylbenzylidene)sorbitol(DMDBS) were prepared from sorbitol and p-methylbenzaldehyde and 3,4-dimethylbenzaldehyde in the presence of a acid catalyst, respectively. On optimizing the synthetic process, the yields were up to 99% more than the ones reported in the previous literatures. The industrialization of process in this paper had been accomplished.In the process of preparing MDBS with toluene/methanol system as solvent, the suitable acid catalyst was C12 alkyl benzenesulfonic acid. Toluene was more advantage to converting the gel state to wet powder than cyclohexane and the lower speed of removing the mixture of methanol and resultant water was in favor of reaction. The addition of toluene/methanol resulted in high yields. The p-methylbenzaldehyde was preferably used in an amount of 2.3 moles per mole of sorbitol. The presence of DMF and DMSO were adverse to condensation reaction of sorbitol and p-methylbenzaldehyde.The study of work-up process indicated that toluene, methanol, cyclohexane, acetone and the recovered mixture of methanol and water were suitable solvents for the purification of the products after neutralization and washing with water. The presence of a certain amount of water in the work-up procedure did not affect the quality of the product. Some additives such as stearate, trialkylamine and some antioxidants could improve the applying properties by improving melt point of MDBS up to 250℃, trialkylamine with a single long carbon chain was especially favor of improving the properties of products. The industrialized yield could be up to 90%.For the process of preparing DMDBS, suitable solvent was cyclohexane/methanol system, and the suitable acid catalyst was C12 alkyl benzenesulfonic acid. The 3,4-dimethyl benzaldehyde was preferably used in an amount of 2.1 to 2.3 moles per mole of sorbitol. The portionwise addition of 3,4-dimethylbenzaldehyde was helpful to converting the gel state to wet powder. Additionally feeding cyclohenane/methanol and maintaining at a high temperature for a certain reaction time could achieve high yields. The product yields in the laboratory experiments were up to 99%.The solution of trialkylamine in toluene was most effective solvent capable for the purifying products in work-up procedure. The melt points of DMDBS were up to <WP=5>261℃ and the yields were not less than 95%. The quality of DMDBS was identical with the imported products’.Nucleating agents MDBS and DMDBS synthesized according to the present method were tested through injection molding and granulation and their applying properties were the same as first-class products in the world.更多还原