丙烯醛水合催化剂B101失活机理及提高其稳定性的研究

Study on the Stability Improvement and Deactivated Mechanism of B101 Resin Catalyst for the Hydration of Acrolein

采用固定床连续流动反应器考察了螯合离子交换树脂的丙烯醛水合反应稳定性,并通过测定反应前后树脂的含水率、酸交换量、组成元素等,分析了树脂活性降低的原因。结果表明,反应前后B101树脂的骨架结构基本上没有发生变化,树脂表面的官能团基本没有流失;B101树脂表面的活性中心H+被部分金属离子如Ca2+、Mg2+取代,而导致催化剂活性中心数减少;而树脂催化剂活性降低的关键原因在于反应过程中生成的聚合物覆盖了活性位所致。通过对反应体系的阻聚和优化丙烯醛水合反应的工艺条件,大大提高树脂催化剂的反应稳定性:以阻聚性能较好的HQ+ZJ-701为阻聚剂,反应空速1.0h?1,丙烯醛质量分数为(11±1)%,在2000h反应考察过程中,通过逐步提高反应温度来补偿催化剂活性的下降,可以使丙烯醛转化率保持在50.0%左右,3-羟基丙醛选择性维持在89.0%,并且反应运行平稳。

Using a fixed-bed reactor, the stability of chelating ion exchanger resin （B101）, which was used as the catalyst for the hydration of acrolein, was studied. It is found that the activity of B101 decreases with prolongation of reaction time. In order to find out the factors causing the deactivation of B 101, the water content, the ratio of acid exchange and composing elements of B101 before and after reaction were determined. The results show that before and after reaction the structure of resin B101 almost keeps unchanging and the function groups on the surface of the resin maintain without loss basically, but some H^＋, the active center of B101 on its surface, are replaced by metal ions such as Ca^2＋, Mg^2＋, which results in the decrease of active center number of B 101. However, it is found that the overlay of polymer byproducts on the resin activity centers is the key factor causing the deactivation of B 101. Experiments show that through inhibiting the polymerization of the reacting system and optimizing the reaction conditions of acrolein hydration can enhance the reaction stability of B 101 resin. Using HQ＋ZJ-701 as polymerizing inhibitor, acrolein mass fraction of （11±1）% and space velocity of 1.0 h^-1, increasing the reacting temperature gradually to compensate the activity decrease of catalyst B101 during 2000 h of examining experiment, the conversion of acrolein can keep at about 50.0%, the selectivity of 3-hydroxypropanal maintain around 89.0%, and the hydration reaction progresses steadily.