The invention relates to a preparation method of a high-efficiency environmental-protection compound
ion liquid catalyst used for synthesizing high-quality
propene carbonate. The invention has the technical scheme of comprising the following steps of: (1) reacting halogenated
alkane and methylimidazole in a reaction kettle according to a proportion; (2) washing by using an ester compound,
settling after stirring fully, and stratifying; (3) distilling off the unreacted halogenated
alkane, the ester compound and light impurities under a decompression condition; (4) adding a
metal halide catalysis aid to obtain a novel compound
ion liquid catalyst; and (5) taking
propylene oxide and
carbon dioxide as raw materials and novel compound
ion liquid as the catalyst, and synthesizing the
propene carbonate. The invention has the advantages that the cost of the catalyst is low, the inactivation of the catalyst is slow, the service life is long, and the annual use cost is equivalent to 1 / 4 to 1 / 5 of that of a tetraethyl
ammonium halide catalyst; and the activity of the catalyst is high, the
reaction speed is high, the selectivity is high, and the yield of the
propene carbonate can reach 97 to 98 percent.