Hydration of α-pinene homogenous catalyzed by acidic polyether-modified ammonium salt ionic liquid in “microreactor”

Abstract

Water-soluble ionic liquids (ILs) with the nonionic polyether modified ammonium (Ac18n) as cation and [HSO4]−, [H2PO3]−, [PTSA]−, or [BF4]− as anion were synthesized and the critical solution temperature (CST) of these ILs in α-pinene were studied. The results showed that the new ILs ([Ac1820]+[HSO4]− and [Ac1820]+[H2PO4]−) were of CST in α-pinene at 80 °C. Then, the new ILs was applied in hydration of α-pinene as catalysts. During the process of reaction, catalysts would carry water molecules to phase of α-pinene and therefore to form the micro-group of water-in-oil. The micro-group is regarded as a micro-reactor for its acidic group, in which the catalytic reaction would have taken place homogeneously when the reaction temperature (T) is higher than CST. When the reaction completed (T < CST), the catalyst would precipitate out from the product, and be recycled efficiently.