Organic Catalysis with Ordered Solid Sulfonic Acids

3 Organic Catalysis with Ordered Solid Sulfonic Acids 

Mesoporous sulfonie acids are of particular interest for reactions involving molecules that are too large to access the smaller pores of conventional molecular sieves or for the preparation of bulky reaction products. In the hydroxyalkylation of methylfuran with acetone, the ordered mesoporous sulfonic acids surpass large pore zeolites such as H-Beta, with an excellent yield of 82 % for 2,2-bis(5-methyl-furyljpropane instead of 45 % for H-Beta [30]. The activity of the sulfonic MCMs is also clearly superior to that of zeolites Beta and Y in the o-sorbitol dehydration-esterification forming isosorbide dilaurate, or in the liquid biphasic preparation of monoesters starting from various polyols and fatty acids [30]. The catalyst of Stein and co-workers was highly active and selective in the tetrahydropyranylation of ethanol with 2,3-dihydropyran [31]. In this type of reaction also the non-modified H-MCM-41 material is an excellent catalyst [40]. 

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S.2.3 Organic Catalysis with Ordered Solid Sulfonic Acids... 

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