Method for directly synthesizing sucrose fatty acid ester by biodiesel and sucrose

The invention provides a method for directly synthesizing sucrose fatty acid ester by biodiesel and sucrose, in which a solvent-free method is adopted to synthesize the sucrose fatty acid ester under the protection of N2 and the barometric pressure of 1, and an isovolumetric immersion method is adopted to prepare a load-type solid base catalyst by immersion; then potassium stearate is added after the biodiesel is mixed with the sucrose, the mixture is reacted until the reaction system presents in a faint yellow emulsion, then the load-type solid base catalyst is added to continue to react, temperature is raised during stirring, N2 is introduced, methanol generated in the reaction process is removed when air in the reaction system is driven away, warming reaction is carried out under the protection of the N2, then the reaction system is cooled, the introduction of N2 is stopped, water is added to stop reaction, and the product is stirred for 10min at the temperature of 80 DEG C; and the crude product is processed to obtain the refined product of the sucrose fatty acid ester. After the crude product is purified by a solvent extraction method, the product purity is above 98%, the N2 can be reused, and the catalyst can be recycled.