Solid Acid Catalytic Application Of The Acetal Ketal Synthesis

The acetal (ketal) were used in several areas for many years, Many acetals (ketals) had been prepared both at home and abroad, which have been widely used for spices, resin and the pharmaceutical industry. The synthesis of acetals were applied to carbonyl or alcohol hydroxyl protection and synthesis of the target product, as its reversible. The structure of acetals (ketals) are similar with ether's, and their chemical stability are very good in alkaline medium. They have many types of aroma, their raw materials are very abundant, and their production process are very simplely. The synthesis and application of acetals (ketals) have been searched by many people continuously.Many organic reactions are all belong to acid catalytic reaction, condensation reaction is its typical representative. Adopts the traditional liquid acid catalysts have many shortcomings, organic chemical workers has been looking for alternative liquid acid solid acid catalyst since long-term. The studies showed that the application of solid acid catalyst can avoid of many faults. Some solid acid catalyst with special structure, the active position and orientation endued solid acid catalyst with good activity and selectivity and special properties. Therefore, the development and research of solid acid catalyst to be used in organic reaction has important academic research value and broad application prospect. For many years, solid acid catalyst is an active field of research for organic chemical, people have developed many types of solid acid catalyst for further application in petrochemical and chemical field, which has laid the solid foundation.Taking cation exchange resin and solid super acid catalytic as modern solid acid catalyst, this paper prepared several acetals and shrink ketones, and optimized the reaction process. The classification and application in organic synthesis of cation exchange resin and solid superacid were summarized in this paper. The solid superacid were used for pentaerythritol dual shrinked benzaldehyde were investigated. The melting point, infrared spectra and nuclear magnetic resonance of products were determinated. On this basis, the influence of the reactants molar ratios, catalyst dosage, reaction time and water entrainer content to the reaction were researched. The results showed that the solid super acid is an ideal catalyst, as it has good catalytic activity, simple follow-up processing, good product yield when it was used in preparing acetals.Then the cation exchange resin were used for pentaerythritol dual shrinked cyclohexanone, acetophenone and benzaldehyde,1,4-Cyclohexanedione dual shrinked glycol,1,2-Propylene glycol,1,3-Propylene glycol and 1,4-butanediol were discussed. The melting point, infrared spectra and nuclear magnetic resonance of products were determinated. On this basis, the influence of the reactants molar ratios, catalyst dosage, reaction time and water-entrainer content to the reaction were researched. The results showed that the cation exchange resin is an ideal catalyst, as its mild reaction condition, good product yield, simple operation when it was used in preparing acetals(ketals). The experimental results provides important references for the industrial application of the solid acid catalyst be used in synthesis acetals(ketals).