Method for synthesizing aliphatic polycarbonate polyols

Abstract

The invention relates to a method for synthesizing aliphatic polycarbonate polyols by transesterification synthesis. The transesterification is carried out on carbonate and aliphatic diols under the catalysis of a high-efficient catalyst, and the polycarbonate polyols with a plurality of structures and adjustable molecular weights and degrees of hydroxyl functional groups can be obtained by regulating the types of the diols. The method has the advantages of short reaction time, high utilization rate of equipment and reduced production cost, thereby leading the large-scale production and the applications of the aliphatic polycarbonate polyols to be possible. The method for preparing the aliphatic polycarbonate polyols comprises the following steps: adding a catalyst, butanediol and the carbonate into a reactor according to a certain material ratio, introducing nitrogen for replacing air in the reactor, increasing the temperature at normal pressure to 180-190 DEG C, carrying out reaction for 2-4h, dropping the pressure to 100-20000Pa, carrying out the reaction for 4-10h, and introducing the nitrogen for cooling a product, thereby obtaining the polycarbonate polyols.

Description

Technical field [0001] The invention relates to a method for synthesizing aliphatic polycarbonate polyols through transesterification of aliphatic polyols and organic carbonates. Background technique [0002] Aliphatic polycarbonate polyol is a polymer with hydroxyl groups at both ends of the molecule, and the main chain of the molecule contains repeating units of aliphatic alkylene and carbonate groups. It is very different from traditional polycarbonate materials, and is different from aliphatic polyols. Ester polyols are similar to polyether polyols and are widely used in synthetic leather, TPU, SPANDEX, adhesives, coatings and other fields. Its important downstream product, polyurethane material, is widely used in construction, chemical industry, light industry, electromechanical, metallurgy, medical and health and other fields due to its excellent performance and wide variety of characteristics. Compared with polyurethanes synthesized by traditional polyols (polyester polyo...

AI Technical Summary

Problems solved by technology

[0003] Because the raw material phosgene used is highly toxic, and a large amount of hydrogen chloride is produced as a by-product, which causes serious corrosion to the equipment, the generation conditions are harsh, and the pollution is relatively large. The phosgene method has been basically eliminated (DE1595446A1)

The cost of synthesizing cyclic carbonates is relatively high, therefore, the synthesis of polycarbonate polyols by ring-opening polymerization of cyclic carbonates has little industrial application value

Carbon dioxide is an extremely abundant and cheap C1 resource on the earth, but the carbon dioxide epoxide regulation copolymerization method can only synthesize polycarbonate polyols with specific epoxide structures (CN101024685A, CN1060299A)

[0004] U.S. Patent US065360A1 discloses using tetraisopropyl titanate as a catalyst to catalyze the transesterification of dimethyl carbonate and glycol to synthesize polycarbonate diol, but the yield is low

U.S. Patent US0125576 discloses to use the organic compound of rare earth element and VIIIB metal element as catalyst to catalyze dimethyl carbonate or diethyl carbonate and dibasic alcohol transesterification to synthesize polycarbonate diol, and the organic compound of ytterbium and lanthanum has relative to reaction Good catalytic activity, but poor selectivity

European patent EP1134248 discloses that organotin compounds are used as catalysts to catalyze the transesterification of dimethyl carbonate and glycols to synthesize polycarbonate diols, but the activity is poor, and organotin compounds are potential carcinogens in the human body

Chinese patent CN101029127A discloses a KF heterogeneous catalyst loaded on a carrier to catalyze the transesterification of dimethyl carbonate or diethyl carbonate and dibasic alcohols to synthesize polycarbonate diols, but the reaction time is long and the activity is poor

However, ethylene carbonate is unstable in ethylene glycol and will decompose (Chen Lantian et al., Petrochemical Technology and Application, 2008, 26(3), 216-218)