Study On The Synthesis, Characterization And Hydrolytic Property Of Pentaerythritol Acetals(ketals)

The thesis contains five parts, which reports that the synthesis, characterization and acid hydrolytic property of pentaerythritol acetals (ketals) with the catalysis of p-toluene sulfonic acid. Among them, focus of this thesis is the research of pentaerythritol monoacetals (monoketals) and pentaerythritol hetero diacetals (diketals).The first part is about the synthesis of pentaerythritol diacetals (diketals). We use benzene and N,N-dimethylformamide (DMF) as the solvent separately, comparing the synthesis of six pairs of diacetals (diketals) in two phases and single phase solution. The diacetals (diketals) are received only in two phases solution, while monoacetals (monoketals) and diacetals (diketals) can be separated in the single phase solution. This proves that pentaerythritol monoacetals (monoketals) synthesized firstly can react with aldehydes (ketones) rapidly dissolved in the same phase to generate diacetals (diketals).The second part is about the synthesis of pentaerythritol monoacetals (monoketals). The report about them is not much and they can be synthesized mainly in the single phase solution. The selection of solvent and the material ratio of reactants are the key of their synthesis. The first method: six monoacetals (monoketals) are synthesized in DMF with reduced pressure. The second method: six monoacetals (monoketals) are synthesized in DMF and cyclohexane which takes water out of the system. The second method is more convenient and easier than the first method. In addition, based on the second method, the best reaction conditions of 5,5-dihydroxymethyl-2-(2-chlorophenyl)-1,3-dioxane are studied.The third part is about the synthesis of pentaerythritol hetero diacetals (diketals). The synthesis of these compounds is very little and more difficulty. When pentaerythritol monoacetals (monoketals) react with another aldehyde (ketone) to give hetero diacetals (diketals), the exchange of the carbonyl group can be occured. The better exchange ability of the carbonyl group will replace the weaker one to obtain diacetals (diketals). Through experiments, we compare the the exchange capacity of four aldehydes (ketones) in the reaction within certain time. On this basis, fifteen pentaerythritol hetero diacetals (diketals) are synthesized by the reaction six pentaerythritol monoacetals (monoketals) with other five aldehydes (ketones) successfully. We described that the synthesis of pentaerythritol hetero diacetals (diketals) are based on the exchange ability of the carbonyl group.The fourth part is about the crystal structure of five pentaerythritol acetals (ketals). We present the crystal structure of two diacetals (diketals), two monoacetals (monoketals), and a hetero diacetal (diketal). We combine the crystal structure with 1HNMR to identify five groups 1HNMR.The fifth part is about the acid hydrolytic property of 9,9-dihydroxymethyl- -7,11-dioxa-spiro[5.5], for the latter work that the acid hydrolytic property of the cleavable surfactants founds the theory.This paper reports the synthesis of pentaerythritol acetals (ketals) by the study of six diacetals (diketals), six monoacetals (monoketals) (four are new compounds) and fifteen hetero diacetals (diketones) (fourteen are new compounds); analyze five crystal structure of compounds; study acid hydrolytic property of a pentaerythritol monoketal.