酸处理改性Hβ分子筛催化合成乙基蒽醌

采用微波辐射法，对Hβ分子筛进行酸处理改性，并通过NH₃-TPD、XRD和吡啶－IR对分子筛进行表征，考察改性前后分子筛酸性质和晶相变化,采用改性的Hβ分子筛催化乙苯和苯酐合成乙基蒽醌。结果表明，无机酸改性分子筛时，由于酸性太强，溶解了大量分子筛的铝物种，减小了分子筛固有的酸催化中心数，使分子筛的催化活性大幅度下降，不适合作为Hβ分子筛的改性试剂。有机酸对Hβ分子筛的改性效果较好，以0.1 mol·L^-1马来酸处理后的分子筛催化效果最好，苯酐转化率为51.53%，乙基蒽醌选择性为39.10%，乙基蒽醌收率最高可达20.15%。采用马来酸和Ce(NO₃)·6H₂O复合改性分子筛，乙基蒽醌选择性为54.0%，乙基蒽醌收率最高可达23.5%，选择性比马来酸单独改性时提高约15个百分点，催化效果明显提高。

Synthesis of ethyl anthraquinone over Hβ zeolites modified by acid

Hβ Zeolite was modified by acid and microwave radiation method. The acidic properties and crystal phase of as-synthesized Hβ zeolites prior to and after modification were characterized by means of NHa-TPD ,XRD and Pyridine-IR. The catalytic performance of modified Hβ zeolites for Friedel-Crafts reaction of ethyl benzene with phthalic anhydride to ethyl anthraquinone was investigated. The results showed that inorganic acids as the modification reagents were not suitable for Hβ zeolite, because the inorganic acid was too strong,a large number of aluminum species of molecular sieve were dissolved,the number of inherent acid catalytic centers of molecular sieve was reduced, and the catalytic activity of molecular sieve modified by inorganic acid decreased substantially. HI3 zeolites modified by organic acids exhibited better catalytic performance, and Hβ zeolites modified with 0.1 mol ·L^- 1 maleic acid possessed the best catalytic properties. The conversion of phthalic anhydride, the selectivity to and the highest yield of ethyl anthraquinone were 51.53% ,39.10% and 20.15% ,respectively. Using composite modified Hβ zeolite with maleie acid and Ce （NO3 ） · 6H2O as the catalyst, the highest yield of ethyl anthraquinone reached 23.5%, and the selectivity to ethyl anthraquinone was 54.0%, which was increased by 15 percentage point compared with Hβ zeolite modified with maleic acid. The catalytic effects of composite modified Hβ zeolite was enhanced obviously.