M. Selva, E. Militello, Massimo Fabris
Jan 3, 2008
Citations
0
Influential Citations
36
Citations
Journal
Green Chemistry
Abstract
At 165–200 °C, in the presence of sodium-exchanged faujasites (NaX or NaY) as catalysts, the reaction of dimethyl carbonate with benzyl-, o- and p-methoxybenzyl-, p-hydroxybenzyl-, diphenylmethyl-, and triphenylmethyl-alcohols (1a, 2a,b, 3a, 4a, and 4c, respectively), produces the corresponding methyl ethers in up to 98% yields. A peculiar chemoselectivity is observed for hydroxybenzyl alcohols (compounds 3a and 3b, para- and ortho-isomers) whose etherification takes place without affecting the OH aromatic groups. Acid–base interactions of alcohols and DMC over the faujasite surface offer a plausible explanation for the catalytic effect of zeolites NaY and NaX, as well as for the trend of reactivity shown by the different alcohols (primary > secondary > tertiary). However, in the case of substrates with mobile protons in the β-position (i.e.1-phenylethanol and 1,1-diphenylethanol), the dehydration reaction to olefins is the major, if not the exclusive, process.