MgO-HM复合催化剂上萘的甲基化

Methylation of Naphthalene over Composite Catalyst MgO-HM

制备了MgO-HM复合催化剂,采用氨程序升温脱附(NH_2-TPD)和吡啶红外光谱(Py-IR)对催化剂进行表征,并考察了MgO含量和反应条件对MgO-HM催化萘与甲醇烷基化反应的影响。结果表明,当MgO质量分数为0.50%时,催化剂具有较大的酸量,且催化剂中的L酸比例较高。以MgO的质量分数为0.5%的MgO-HM为催化剂,在290℃和1.0 MPa条件下反应60 min,萘的转化率为36.4%,β-甲基萘(β-MAN)在MAN中的物质的量分率达到96.2%,2,6-二甲基萘(2,6-DAN)在DAN中的物质的量分率为49.0%。该催化剂稳定性能好,使用4次后,萘的转化率保持在36.0%以上,βMAN在MAN中的物质的量分率达到96.1%,2,6-DAN在DAN中的物质的量分率在48.0%左右。

Composite catalysts MgO-HM were prepared and characterized by means of ammonia program temperature desorption （NH3-TPD） and pyridine infrared spectroscopy （Py-IR）, and the catalytic performance for methylation of naphthalene was investigated in a 100 mL stainless steel batch reactor. The results showed that the acid amount and the ratio of L acid to B acid of MgO-HM catalyst with mass fraction 0.50% of MgO （0.50%MgO-HM） were higher than those of HM. The conversion of naphthalene, the molar ratio of 2,6-dimethylnaphthalene （2,6-DAN） to DAN and the molar ratio of β-monomethylnaphthalene （β-MAN） to MAN reached 36. 4%, 49. 0% and 96. 2%, respectively, over 0. 50%MgO-HM catalyst under the reaction conditions of 290 ℃, 1.0 MPa and reaction time 60 min. The stability of 0.50%MgO-HM catalyst exhibited good and the conversion of naphthalene, the molar ratio of 2,6-dimethylnaphthalene （2,6-DAN） to DAN and the molar ratio of β-monomethylnaphthalene （β-MAN） to MAN were above 36.0%, 96.1% and 48.0%, respectively, after the catalyst had been used 4 times.