the molar ratio of 1.25: 1 of the monohydramine and maleic anhydride, into the reaction kettle, under the alkali catalysis, at 140~150 DEG C esterification reaction. The acid value was measured after 4~8h of the reaction, and when the acid value dropped to 5 mgKOH/g, the reaction ended. After treatment, the ester is injected into the sulfonation kettle, and sodium bisulfite is added for sulfonation. The molar ratio of ester to sodium bisulfite is controlled at 1: 1.05. A certain amount of ethanol was added as solvent, and the reaction was carried out at 110~120 ℃ for 2h, and sulfonation was completed.
The sulfonated product is injected into the acylation kettle, and undecenoyl chloride is added to carry out the acylation reaction.