Method for preparing 5-hydroxymethylfurfural in a temperature-controlled phase separation solvent system

A method for preparing 5-hydroxymethylfurfural in a temperature-controlled phase separation solvent system, comprising:

• S1:
• Constructing a temperature-controlled phase separation solvent system;
• wherein the solvent system comprises an aqueous betaine hydrochloride solution and an organic solvent, the organic solvent is acetone;
• the volume ratio of the organic solvent to the aqueous betaine hydrochloride solution ranges from 1:1 to 5:1, and the concentration of betaine hydrochloride in the aqueous betaine hydrochloride solution ranges from 25 to 40 wt %;
• S2:
• Adding a defined amount of carbohydrate to the solvent system and heating the mixture to conduct a dehydration reaction, with the aqueous betaine hydrochloride solution serving as the reaction phase and the organic solvent serving as the extraction phase to form phase stratification;
• wherein the reaction temperature ranges from 100 to 180° C., the reaction time ranges from 30 to 180 min, and the concentration of the carbohydrate ranges from 5 to 40 wt %;
• S3:
• After completion of the reaction, cooling the reaction mixture at room temperature for a period of time, whereby betaine hydrochloride precipitates in crystalline form;
• the product is present in a mixed solution of the organic phase and deionized water, and 5-hydroxymethylfurfural is obtained via isolation and purification of the mixed solution;
• wherein in step S2, the carbohydrate is selected from any one of fructose, high-fructose syrup, and inulin.