Indirect Hydrogenolysis Of Glycerol To1,3-Propanediol

1,3-propanediol(1,3-PDO) is an important chemical which is widely used in thefields of chemical engineering, medicine and food. Conversion of glycerol to1,3-PDO is a way of high value-added utilization of glycerol. In this dissertation, themethod of indirect hydrogenolysis of glycerol to1,3-PDO was carefully studied andimproved. The related work was summarized as follows:The process of indirect hydrogenolysis of glycerol is as follows:2-phenyl-1,3-dioxan-5-ol (HPD) was firstly prepared by acetalization of glycerol, andthen HPD was transformed via toxylation and hydrolysis into2-tosyloxy-1,3-propanediol(TPD),1,3-PDO was finally prepared by hydrogenolysisof TPD. The effect of solvents on the acetalization of glycerol was eva luated. Theyield of HPD was19%when benzene-ligron(1:1) was used as the reaction solvent.The influence of the mother liquor on the acetalization was investigated. The resultsrevealed that the mother liquor leads to the almost only product of HPD formed in theacetalization, and the yield of HPD was95%.The hydrogenolysis of TPD was catalyzed by Raney Ni, and the pathway wasinvestegated. The conditions of the reaction were optimized by employing the singlefactor method as well. The results indicated that the hydrogenolysis of TPD is aprocess combined with deacidification and hydrogenation. Temperature and theamount of catalyst were the main factors to affect the reaction. Under the optimizedconditions, the conversion of glycerol was91%, and the selectivity of1,3-PDO was75%. A process for the purification of1,3-PDO was set up, and the purity of1,3-PDOapproached to98%by using this process. To avoid the corrosion of catalyst by the acid formed in the hydrogenolysis ofTPD, some bases were added as acid binding agents and of which the effect wasevaluated. The conditions of hydrogenolysis of TPD in the basic medium wereoptimized and the stability of the catalyst was investigated. It can be concluded fromthe results that the acid binding agent protected the catalyst. Triethylamine was thebetter base. Temperature and hydrogen pressure were the main factors to affect thereaction with the addition of triethylamine. The catalyst maintained activity afterusing3times under the optimized conditions.