3-蒈烯催化转化反应及应用研究

Catalytic Transformation and Application of 3-Carene

以建立3-蒈烯的高效利用途径为目的,对其催化转化进行了深入研究,结果表明:金属类催化剂对促进3-蒈烯发生三元环开环脱氢具有很高的活性,尤其是在铂催化下脱氢产物伞花烃的选择性超过90%,其中,间伞花烃与对伞花烃的质量比约为7∶2;分子筛催化同样会导致3-蒈烯发生三元环开环并脱氢,随着反应温度升高,脱氢产物对伞花烃进一步裂解生成甲苯等芳烃化合物,ZSM-5型分子筛在促进裂解反应方面能力突出。在此基础上,建立了以金属铂与ZSM-5型分子筛为复合催化剂,3-蒈烯经连续催化转化制备甲苯与间伞花烃的工艺路线,在V(Pt/Al_2O_3)∶V(ZSM-5)1∶1,280℃的条件下,原料转化率接近100%,产品总得率大于85%,最终产物甲苯得率约25%,纯度大于99%;间伞花烃得率约46%,纯度大于95%。

With the purpose of establishing an application method, studies on the catalytic transformation of 3-carene were carried out. The results indicated that metal catalysts, especially the platinum, had excellent ability to promote the ring opening and dehydrogenation of three-membered ring in 3-carene. With platinum-catalysis, the selectivity of dehydrogenation product cymene exceeded 90% and the mass ratio of m-cymene to p-cymene was nearly 7：2. The ring opening and dehydrogenation of 3-carene could be similarly catalyzed by molecular sieves. However, with the rising of temperature, the dehydrogenation product p-cymene would further be cracked to aromatics like toluene. Molecular sieves ZSM-5 showed a prominent activity in promoting this reaction. On the basis of these results, a continuous process of preparation of toluene and m-cymene from 3-carene was established by using platinum and ZSM-5 as a kind of composite catalyst. The conversion rate of raw material was nearly 100% and the yield of all products was more than 85%. The yield and purity of one of the final products toluene were 25% and 99%, respectively. While m-cymene were 46% and 95%, respectively, with reaction conditions at the volume ratio of Pt/Al2O3 to ZSM-5 1：1 and 280℃.