The Synthesis Of Propylene Glycol Oligomer

Propylene glycol oligomers are a class of important organic chemical products. Especially, the dipropylene glycol (DPG) is used in wide field. At present, the propylene glycol oligomer is as a by-product coming from the synthesis of 1,2-propanediol (1,2-PDO) using propylene oxide (PO) and water. In this thesis, the synthesis of propylene glycol oligomer had been studied through the reaction of PO with 1,2-PDO/1,3-PDO. Reaction conditions were selected and optimized by orthogonal experiments as well as the single factor experiments; Organic amine catalyst with high conversion rate and the ideal selectivity was developed; with organic amine as the active component, the support catalyst was prepared and its catalytic performance was researched preliminarily.Results from the research of propylene glycol oligomer synthesis using 1,2-PDO and PO showed that the organic amine catalyst with good performance was chosen as NEA. The best optimization experimental operating conditions were obtained through the study of orthogonal experimental and single-factor experiment. The reaction condition was specifically described as followings: reaction temperature 100℃, reaction presser 2atm, reaction time 90min, the mol ratio of PDO to PO 3, and the does of catalyst 0.06. At this time, the DPG yield was more than 70% and the selectivity more than 90%. Through the thin-layer chromatography, gas chromatography and mass spectrometry, the structure of the product was characterized; through the boiling point, polarity as well as the analysis of gas chromatography, DPG three isomers have been identified. The main physical properties were measured and it was found the same value with the literature.Results from the research of propylene glycol oligomer synthesis using 1,3-PDO and PO showed that DEA was suitable for the reaction of O-alkylation; the best optimal condition were: reaction temperature 100℃, reaction presser 2atm, reaction time 90min, the mol ratio of PDO to PO 4, the does of catalyst 0.10. At this time, the DPG yield was more than 60% and the selectivity more than 90%. Through the gas chromatography and mass spectrometry, the structure of the product was characterized. Because the homogeneous catalysis has a series of problems, such as product separation difficulty and catalyst recovery difficulty, the heterogeneous catalysis was studied preliminarily. With organic amine as the active component, the support catalyst was prepared. Through the study on the aspects of catalytic mechanical strength, thermal stability of alkali content as well as the catalytic performance, the method of preparing support catalyst was determined. The amine NEA and base CS were selected to mix, in order to enhance the catalyst performance. The catalyst performances were evaluated for determining the best optimal preparation method of supported catalyst. The method can be described as following: the solution of 10(w)%CS to NEA for the active component, through impregnation the support catalyst was prepared.