| Summary: | <p>The cyclization of citronellal is an important step in menthol synthesis. The selectivity of FeCl3 and ZnCl2<br />
catalysts was evaluated for this reaction. The cyclization reaction of citronellal was studied experimentally and<br />
theoretically. Citronellal was isolated using fractional distillation under reducing pressure. The reaction mixture<br />
contained citronellal, acetic anhydride, and Lewis acid with mol ratio of 2:6:1. The reaction was conducted at 80oC<br />
for 3 hours with stirring. FeCl3 and ZnCl2 catalysts showed high activity but low selectivity. The products were<br />
analyzed by means GC-MS and IR spectroscopy. The major products by FeCl3 catalyst were identified as p-cymene<br />
(36.13%) and citronellyl acetate isomeric (39.97%). At lower temperature, the replacement of FeCl3 by ZnCl2 showed<br />
the increasing of citronellyl acetate and isopulegyl acetate. The structures of reactants, products, and intermediates<br />
were studied by DFT/B3LYP method.</p>
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