Catalytic synthesis of acetals and ketals with I₂/PAn

A new environmental friendly catalyst, I₂/Pana, was prepared. The catalytic activities of I2/ PAn in synthesizing 2-methyl-2-ethoxycarbonylmethyl-1, 3-dioxolane, 2, 4-dimethyl-2-ethoxycarhonylmethyl-1, 3-dioxolane, cyclohexanone ethylene ketal, cyclohexanone 1, 2-propanediol ketal, butanone ethylene ketal, butanone 1, 2-propanediol ketal, 2-phenyl-1, 3-dioxolane, 4-methyl-2-phenyl-1, 3-dioxolane, 2-propyl-1, 3-dioxolane, and 4-methyl-2-propyl-1, 3-dioxolane were reported. It is demonstrated that I₂/PAn is an excellent catalyst. Various factors concerned in these reactions were investigated. An optimum condition was found, that is, the molar ratio of aldehyde/ketone to glycol is 1/1.6, the mass ratio of the catalyst used to the reactants is 0.2 %, and the reaction time is 1.0 h. Under the optimum condition, the yields of these 10 kinds of acetals/ketals are 47.3%-94.2%.