42598-91-4Relevant articles and documents
Synthesis of Formaldehyde Acetals by Phase Transfer Catalysis
Wang, Maw-Ling,Chang, Shahng-Wern
, p. 2149 - 2155 (2007/10/02)
By employing phase transfer catalysis, formaldehyde acetals were synthesized from the reaction of alcohols and dibromomethane at moderate temperatures.Using a high alkaline concentration, the reaction could be improved to obtain a 100percent yield by reacting dibromomethane and 1-alcohol employing tetrabutylammonium bromide (TBAB) as a phase transfer catalyst.Six kinds of alcohols with various structures, four sorts of solvents with various dielectric constants and seven types of catalysts were examined to test their reactivities to the reactions.Only one unique product with two alkoxides substituents was observed which indicated the presence of a rather fast reaction rate during the second reaction of the organic phase.The reaction was dramatically enhanced by adding a small amount of quaternary ammonium salt (QX) to obtain a 100percent yield utilizing the alcohols with nonbonding electron pairs within a short period of reaction time.The conversion was also observed to be strongly dependent upon the structure of the quaternary ammonium salts.The reaction rate and the product yield were satisfactorily accounted for the chemical reaction equilibrium of alcohols and KOH in the aqueous phase, the hydration of the active catalyst (QOR) in the organic phase and the distribution of QOR between two phases.
