کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
62701 | 47651 | 2007 | 12 صفحه PDF | دانلود رایگان |

New strong Lewis acid SnTf-MCM-41 and SnTf-UVM-7 catalysts with unimodal and bimodal pore systems were prepared in a two-step synthesis in which the triflic acid (Tf) was incorporated to previously synthesized mesoporous tin-containing silicas. The Sn incorporation inside the pore walls was carried out through the Atrane method. The SnTf-UVM-7 catalysts were prepared by aggregating nanometric mesoporous particles defining a hierarchic textural-type additional pore system. Following these procedures, catalysts with different Si/Sn ratios—21.8 to 50.8 for SnTf-MCM-41 and 18.4 for SnTf-UVM-7—were prepared. These new materials were tested in the acylation of aromatic sulfonamides using acetic acid as the acylating agent and in the synthesis of (dl)-[α]-tocopherol through the condensation of 2,3,6-trimethylhydroquinone (TMHQ) with isophytol (IP). The activity data indicate that these heterogeneous catalysts are very active, corresponding to high yields in acylated compounds as 65.5% and very high selectivity to (dl)-[α]-tocopherol (94%, for a conversion of 98%).
Journal: Journal of Catalysis - Volume 251, Issue 2, 25 October 2007, Pages 388–399