Selective Catalytic Hydrogenation Of 3-(4-tert-butylphenyl)-2-methylpropenal

Selective hydrogenation of compounds which containing two or more reducible groups have become more and more attractive in recent years. The selective hydrogenation ofα,β-unsaturated aldehyde is a typical reaction. The hydrogenation product such as saturated aldehyde and unsaturated alcohols are important fragrance and pharmaceutical intermediates. It is of great important theoretical research significance to design high-active catalyst and obtain target products with high selectivity.In this thesis, the selective catalytic hydrogenation of 3-(4-tert-butylphenyl)-2-methyl propenal (PTBMC) to lilial over 5%Pd/C modified by base was investigated. Effects of pretreating ways, organic base and inorganic base on selectivity of lilial were studied and results showed that K2CO3 modification of the catalyst remarkably improved the selectivity of lilial. The conversion of PTBMC was 100% and the selectivity of lilial was up to 98.5% under optimal reaction conditions. Selective hydrogenation of cinnamaldehyde,α-methyl cinnamaldehyde and a-pentyl cinnamaldehyde over 5%Pd/C modified by K2CO3 was also investigated and the selectivity of the corresponding saturated aldehyde was 98.2%,98.1%, 98.2%, respectively. The mechanism of basicity and carbonate ion enhanced the selectivity of saturated aldehyde was explored.Selective Hydrogenation of 3-(4-tert-butylphenyl)-2-methylpropenal to 3-(4-tert-butyl-phenyl)-2-methylpropenol was investigated. Results showed that Ru/C, Pt/C exhibited higher selectivity on the hydrogenation of C=O group. Effects of temperature, solvents and additives on the selectivity of C=O double bond hydrogenation and reaction rate were investigated. The selectivity of 3-(4-tert-butylphenyl)-2-methylpropenol was 76.4% and conversion of PTBMC was 98.5% under optimal conditions.