Studies On The Green Reduction Of Aromatic Aldehydes And Ketones And The Reductive Amination Of Triacetoneamine

The reduction of carbonyl in the aromatic aldehydes and ketones to thecorresponding methylene is of great significance. The traditional Clemmensenreduction and Wolff-Kishner-Huang reaction are of high cost and easy to causeenvironmental pollution.2,2,6,6-tetramethyl-4-aminopiperidine and its derivatives areimportant intermediates of hindered amine light stabilizers. Batch process used inindustry has the disadvantages of mutisteps and environmental pollution. Soestablishing a continuous process for these products is promising. This paper hascarried on the system research.1、The direct reduction of acetophenone was chosen as template reaction, inwhich the conversion of acetophenone was99.35%，the selectivity of ethylbenzenewas99.28%on the selected catalyst Cu20Cr5/-Al2O3. Cu0was found as the activesites of the catalyst. The addition of Cr improved the dispersion of active components,inhibited the aggregation and sintering of Cu microcrystalline, thus enhancing thecatalyst’s activity and stability. When Cu20Cr5/-Al2O3was used for the reduction ofother aromatic ketones, excellent catalytic results were obtained.2、The direct reduction of benzaldehyde was chosen as template reaction, inwhich the conversion of benzaldehyde was93.94%，the selectivity of toluene was99.28%on the selected catalyst Ni30/-Al2O3.3、The reductive amination of triacetone with n-butylamine was chosen astemplate reaction, in which the conversion of triacetone was99.47%，the selectivity ofproduct was99.53%on the selected catalyst Cu20Cr5Ba5/-Al2O3. It’s found that thereplacement of La with Ba improved the dispersion of active components, decreasedthe acidity of the catalyst, therefore, increased the product selectivity.4、The reductive amination of triacetone with1,6-hexamethylenediamine waschosen as template reaction, in which the conversion of triacetone was99.22%，theselectivity of product was93.52%on the selected catalyst Cu20Cr5Fe5/-Al2O3-AB40.It’s found that the introduction of Fe and alumina-B decreased the acidity of thecatalyst and facilitated the desorption of product.5、The reductive amination of triacetone with ammonia was chosen as templatereaction. It’s found that solvent with great solubility and the removal of water could improve the product selectivity. During the optimal cinditions, the conversion oftriacetone was99.14%，the selectivity of product was81.90%.6、Processes for the green reduction of aromatic aldehydes and ketones and thereductive amination of triacetoneamine have been established. The catalysts used arereadily to recycle and the utilization of H2as hydrogen source could efficientlyimprove the reaction’s atom economy.