K改性HY分子筛的制备及催化芳烃苄基化反应研究

Preparation of K modified HY molecular sieves and catalytic benzylation of aromatic hydrocarbons

研究了K改性的HY分子筛的制备及催化芳烃与苯甲醇的苄基化反应的性能。采用等体积浸渍法,制备了一系列不同K负载量的HY分子筛KHY_(1.0),KHY_(2.0),KHY_(3.0),KHY_(4.0)和KHY_(5.0),并将其应用于催化芳烃和苯甲醇苄基化合成二苯甲烷。制备的分子筛通过XRD、SEM、EDS、Py-IR和N_(2)吸附/脱附分析方法进行表征。将芳烃和苯甲醇在373 K下用KHYX催化反应4 h,用气相色谱监测反应进程。结果表明,K离子作为活性组分均匀地分布在分子筛表面,并且K离子的加入并不会破坏HY分子筛的结构。KHY_(2.0)是催化芳烃苄基化反应的最优催化剂,且该类催化剂具有良好的再生性能,在重复使用5次后,催化效果几乎不受影响。

K modified HY molecular sieves were prepared and their catalytic performance in the benzylation of aromatic hydrocarbons and benzyl alcohol to diphenylmethane were studied.A series of HY molecular sieves KHY_(1.0),KHY_(2.0),KHY_(3.0),KHY_(4.0) and KHY_(5.0) with different K loaded were prepared by the equal volume impregnation and applied to catalyze the benzylation of aromatic hydrocarbons and benzyl alcohol for synthesis of diphenylmethane.The modified molecular sieves were characterized by XRD,SEM,EDS,Py-IR and N_(2) adsorption/desorption analysis.The aromatic hydrocarbons and benzyl alcohol were catalyzed by KHY for 4 h at 373 K,and the progress of the reaction was monitored by gas chromatography.The result showed that K is evenly distributed on the surface of the molecular sieve as an active component,and the introduction of potassium ion will not destroy the structure of the HY molecular sieve.KHY_(2.0) is the best catalyst for catalyzing the benzylation of aromatic hydrocarbons,and has excellent regeneration performance.After 5 times of reuse,the catalytic efficiency had almost no influence.