▎ 摘　　要

NOVELTY - The preparation method of titanium dioxide-based composite/Lewis acid composition involves (1) mixing tetrabutyl titanate, graphene, dimethylformamide, and ethanol to form solution (A), (2) mixing water, ethanol and acetic acid to form solution (B), (3) mixing copper salt, zinc salt, silver salt, water and ethanol to form solution (C), (4) dripping the solution (B) and solution (C) into the solution (A), leaving still, drying and grinding to obtain powder substance, (5) calcining the powder substance to obtain titanium dioxide-based composite solid catalyst, and (6) immersing the titanium dioxide-based composite solid catalyst, zinc chloride, and niobium pentachloride in hydrochloric acid, and drying, where the weight ratio of tetrabutyl titanate, graphene, dimethylformamide, and ethanol in step (1) is 20:(5-10):(40-60):(50-70), and the weight ratio of copper salt, zinc salt, silver salt, water and ethanol in the step (3)is 10:(2-4):(0.2-0.6):(20-26):(15-20). USE - Preparation method of titanium dioxide-based composite/Lewis acid composition (claimed) for preparing allantoin. ADVANTAGE - The method enables preparation of titanium dioxide-based composite/Lewis acid composition with excellent catalytic effect. DETAILED DESCRIPTION - The preparation method of titanium dioxide-based composite/Lewis acid composition involves (1) mixing tetrabutyl titanate, graphene, dimethylformamide, and ethanol to form solution (A), (2) mixing water, ethanol and acetic acid to form solution (B), (3) mixing copper salt, zinc salt, silver salt, water and ethanol to form solution (C), (4) dripping the solution (B) and solution (C) into the solution (A), leaving still, drying and grinding to obtain powder substance, (5) calcining the powder substance to obtain titanium dioxide-based composite solid catalyst, and (6) immersing the titanium dioxide-based composite solid catalyst, zinc chloride, and niobium pentachloride in hydrochloric acid, and drying, where the weight ratio of tetrabutyl titanate, graphene, dimethylformamide, and ethanol in step (1) is 20:(5-10):(40-60):(50-70), the weight ratio of water, ethanol and acetic acid in the step (2) is 5:(20-25):(2-3), and the weight ratio of copper salt, zinc salt, silver salt, water and ethanol in the step (3)is 10:(2-4):(0.2-0.6):(20-26):(15-20).