Study On The Synthesis Of Polycarbonate Diols

Polycarbonate diols(PCDL), as a specialy polyols, is one of the primary raw materials for the synthesis of polyurethane. First, the performance and applications of alphatic PCDL is introduced in detail in this paper. Research progress on alphatic PCDL at home and abroad is reviewed. After comparison of diffirent Synthesis methods, transesterification method is selected. DMC and small molecular aliphatic diols are raw materials.In this paper, the hydroxyl conversion rate, yield and the product molecular weight were the evaluation index. The factors such as catalyst and its amount, ratio of reactants, reaction time, reaction temperature and pressure were investigated and obtained the following results.When chose DMC,1,4-butanediol and1,5-pentadiol as the materials, selected triethylamine as catalyst with0.30%wt, reaction ratio equaled1.25, mole ratio between1.4-butanediol and1,5-pentadiol equaled1, reacted in100min under160℃and atmospheric pressure, then reacted in2.5h under6kPa(absolute pressure) and180℃, the Copoly PCDL with molecular weight of about1700was ontained.When chose DMC.1,5-pentadiol and1,6-Hexanediol as the materials, selected triethylamine as catalyst with0.35%wt. reaction ratio equaled1.25. mole ratio between1.5-pentadiol and1.6-hexanediol equaled1. reacted in3h under160℃and atmospheric pressure, then reacted in3h under5kPa(absolute pressure) and180℃, the Copoly PCDL with molecular weight of about2000was ontained.