The method of using the dehydration of glycerol to acrolein by supported ionic liquid catalyzed acid

The invention discloses a preparation method of acrolein, and relates to the field of acrolein preparation by catalyzing dehydration of glycerol. The preparation method is characterized in that: glycerol is used as a raw material, an immobilized ionic liquid is used as a catalyst, and acrolein is prepared by dehydration; the used ionic liquid is acidic ionic liquid [BMIM]BF4 (1-butyl-3-methylimidazolium terafluoroborate) or [BMIM]H2PO4, and the acidic ionic liquid is immobilized by impregnation; the molar selectivity of the acrolein prepared by adding 1-8% of hydroquinone used as a polymerization inhibitor to 10-60% of glycerol aqueous solution used as a reaction solution and reacting under the conditions of atmospheric pressure, reaction temperature of 240-360 DEG C and volume space velocity of 5-15/h can reach 90.4%; and the conversion rate of glycerol can reach 100%. The preparation method has the advantages that the immobilized acidic ionic liquid has higher selectivity in the dehydration reaction of glycerol, the acrolein yield is higher, the reaction stability is good, and the life of the catalyst is long.