Studies On The Catalytic Amination Of Alcohols

Aliphatic amines are important intermediates for the chemical and pharmaceutical industries. Catalytic amination of alcohols is one of the most useful methods for the manufacture of this kind of compounds. Three kinds of catalytic amination of alcohols: intramolecular, intermolecular and both of them occuring at the same time are investigated systematically in this paper. 1. The synthesis of piperazine from N-β-hydroxyethylethylenediamine was taken as a model for the investigation into the intramolecular catalytic amination of alcohols. The used catalysts were characterized by XPS,XRD,SEM. The intermediates and products were analyzed through GC-MS and the mechanism was proposed on the basis of them. The BL0182 catalyst was selected and organic solvents such as dioxane were found benefit to the service life of this catalyst. The conversion of raw material was over 98% and the selectivity to piperazine was about 95% under the optimized reaction conditions. The catalyst showed high activity after 200 hours of experiment. The BL0182 catalyst was successfully used in the synthesis of 2-methylpiperazine and 2,6-dimethylpiperazine, too.2. The synthesis of triethylenediamine was investigated as a model of intramolecular catalytic amination of alcohols to cyclic tertiary amines. A series of catalysts were prepared and examined and BL0308 catalyst was selected. It was found when BL0308 was employed as catalyst, the conversion of the starting material reached almost up to 100% and triethylenediamine was afforded over 90% selectivity under the optimized reaction conditions, and the catalyst worked well within 210 hours .3. The intermolecular catalytic amination of aliphatic alcohols using n-butanol and ammonia as example was studied . The BL0385 catalyst was selected and optimized for this reaction . The conversion of n-butanol was near 100% and the selectivity of n-butylamine was over 84%, while the reaction temperature was 250℃, the ratio of ammonia to alcohol was 6:1 and the hydrogen pressure was 1.5MPa. The catalyst showed high activity after 100 hours of test. The n-butylamide was first detected and the dehydrogenation/hydrogenation mechanism of catalytic amination of alcohols wasproved. The catalyst was successfully used in the synthesis of n-octaylamine and N-ethylethylenediamine, too.4. The cyclization of diethanolamine and methylamine(ethylamine) was taken as a model for the investigation into the intramolecular and intermolecular catalytic amination of alcohols. The reaction was found to be very complex and no desired result was obtained.