新癸酸缩水甘油酯(EPDA)是涂料制备和改性的新型功能性绿色单体,可大幅降低有机溶剂的使用,同时赋予涂料更强的耐水性和抗紫外性能。EPDA和原料环氧氯丙烷(ECH)均含有环氧基团,反应过程具有放热量大、副反应多的特点,这导致目前在间歇反应器中的两步合成过程存在高能耗、高物耗、低效率、低质量等问题。因此,研究EPDA合成过程的反应和传递规律,构建新型催化转化体系,并开发绿色、高效的EPDA连续化生产工艺和设备具有重要的基础理论和工业应用价值。本论文以工业生产中常用的两步法合成工艺为对象,针对第一步新癸酸(NDA)与环氧氯丙烷(ECH)的开环反应和第二步在氢氧化钠水溶液中的闭环反应分别进行了系统的研究。针对第一步酸解开环反应,分析并确认了四甲基氯化铵催化下副产物二氯丙醇(DCP)的两种生成途径均是在氯离子的催化下完成的。以此为基础,发明并制备了无氯离子的四甲基新癸酸铵(TMAN)催化剂,将DCP的浓度降低50%。研究了TMAN催化下的反应动力学,发现TMAN亲核进攻ECH是反应的决速步。通过改变催化剂的阴阳离子,研究了不同有机酸盐催化ECH的开环反应动力学,发现随着阳离子半径的增大和阴离子碱性的增强,催化活性提高。发现提高反应温度可显著提高反应速率,但选择性会随之下降。揭示了选择性取决于反应中间体发生中和反应与分子内闭环反应的相对速率,水的加入可加快质子转移,促进中间体向目标产物的转化,从而提高高温过程的选择性。构建微反应系统,开发了高温反应串联低温老化的两段式连续化工艺,将反应时间从6 h缩短至40 min。针对第二步闭环反应,在微反应器中表征了该快反应的本征动力学,发现实际反应体系的速率要比本征反应速率慢很多,从而明确了非均相传质是控制步骤。构建微反应系统强化液液传质并实现了闭环过程的连续化,将反应时间缩短至间歇搅拌反应器中的1/20,时空收率提高了15倍。本论文以反应和传递的理论研究为基础,通过新催化剂发明,催化转化体系优化,新设备构建和新工艺开发,最终实现了绿色产品EPDA的绿色生产。本论文在基础理论和工程应用方面的创新对高端环氧化学品从间歇到连续的制造模式的转型具有重要意义。
2,3-Epoxypropyl neodecanoate (EPDA) is a new functional and green monomer for coating preparation and modification, which can greatly reduce the consumption of organic solvents and endow coatings with stronger water resistance and UV resistance. Both EPDA and the raw material epichlorohydrin (ECH) contain an epoxy group, whose reactivity is pretty high. This characteristic determines that the synthesis process of EPDA releases large reaction heat and is usually accompanied by many side reactions. The current two-step process to produce EPDA in batch reactors faces the dilemmas of high energy and material consumption, low reaction efficiency and poor product quality. Therefore, studying the reaction and transfer laws, establishing new catalytic system, and developing efficient and continuous processes for EPDA production are of great importance to basic reaction theory and industrial application. This thesis took the two-step process that is commonly used in industrial production as the research object, the ring-opening reaction of neodecanoic acid (NDA) and epichlorohydrin (ECH) in the first step, and the ring-closing reaction in the second step were systematically studied.In the study of the acidolysis ring-opening reaction between ECH and NDA, it was analyzed and confirmed that when using tetramethylammonium chloride as the catalyst, both the two formation pathways of the side product dichloropropanol (DCP) are facilitated by chloride ions. Based on this finding, a chloride-free catalyst, tetramethylammonium neodecanoate (TMAN), was prepared and applied in the ring-opening reaction. In this way, the concentration of DCP was reduced by 50%. The reaction kinetics catalyzed by TMAN was studied in a stirred reactor, it was found that the nucleophilic reaction of TMAN with ECH is the rate-determining step. The relation between the catalyst structure and its catalytic activity was studied via changing the types of anions and cations in the carboxylate catalysts. It was proved that the catalytic activity is enhanced with the increase of cation radius and the anion basicity. It was found that the reaction rate is improved by raising the reaction temperature, however, the selectivity declines as well. The selectivity depends on the relative rate between the neutralization and intramolecular ring-closure of the reaction intermediate. The addition of water can accelerate the proton transfer process and promote the conversion of the intermediate to the target product, thereby improving the selectivity under high temperature condition. A microreaction system that was composed of a continuous microreactor and a stirred reactor was established to realize a two-stage ring-opening process, which combined the rapid conversion stage in series with the slow aging stage. Benefiting from the flexible option of temperature in the consecutive two stages, the required reaction time was shortened from 6 h to 40 min.In the study of the dehydrochlorination ring-closure reaction, the intrinsic kinetics of this fast reaction was characterized in a microreactor. It was found that the actual production process was much slower than the obtained kinetic results, thus proving the heterogeneous mass transfer is the controlling step. A microreaction system was established to enhance the liquid-liquid mass transfer, making the reaction time shorted to 1/20 and the space-time yield increased by 15 times.Based on the theoretical research of reaction kinetics and transport phenomenon, optimization of catalytic system and establishment of microreaction systems, this thesis finally developed an efficient, safe and continuous process and advanced equipment to produce the high-end epoxide, EPDA. The innovations in basic theory and engineering application are of great significance to the transformation from batch to continuous manufacturing mode of high-end epoxy chemicals.