The Technology And Foundation Study On Chemical Synthesis Of Monomer Of Poly(3-hydroxybutyrate)

Poly(3-hydroxybutyrate)(PHB) is the plastic which can be degraded completely by microorganism.β-butyrolactone is the most important raw material of producing PHB. By far, it has not been produced in commercial scale. Therefore, studying the producing method ofβ-butyrolactone is very necessary and of great importance in environmental protection and economy.In this paper, crotonic acid and HBr were selected as raw materials to synthesizeβ-butyrolactone. There were two steps, one is the preparation of 3-bromoubutyric acid, the next is the preparation ofβ-butyrolactone.In the first step, effects of solvent kinds, initiator amount, reaction time and solvent amount on yield were investigated. The optimal reaction conditions were solvent being ethyl ether, initiator amount being 1.50g, solvent amount being 200ml, reaction time being 4d. The results showed that on the basis of achieving literature value, the reaction time was reduced one half.In the second step, orthogonal test was designed to investigate the facts of reaction temperature, reaction time and solvent amount on yield. And the optimal reaction conditions were determined by extension experiment. The average yield was 75.4% which was higher than the literature value of 64%.In addition, in order to provide fundamental data for Industrialization production, the densities, viscosities and solubilities of correlative reaction systerms were measured in this paper. Densities and viscosities of binary systems of crotonic acid with benzene,toluene and ethyl acetate at the temperatures (298.15～343.15K) and of crotonic acid with acetone at the temperatures ( 298.15～323.15K) were measured under atmospheric pressure by using a vibrating U-shaped sample tube densimeter and Ubbelohde suspended-level viscometer. Density and reduced viscosity were fitted by a multiple regression analysis and Jones-Doles equation respectively, and the maximal average relative deviations were 0.00017, 0.00202 and 0.0252.By using laser monitoring technique, solid-liquid equilibrium data of crotonic acid in benzene,toluene and ethyl acetate were measured within the temperature range from 293.15K to 322.15K. Empirical formula andλh equation were used to correlate the solubilities of crotonic acid in three solvents and the corresponding parameters were given. The results showed that empirical formula andλh model could correlate the solubility data of crotonic acid in three solvents and the maximal average relative deviations were 1.07% and 1.04%.