反应详情

Into a 1-liter electromagnetic agitation type autoclave equipped with a reflux condenser were charged 321 g of 3,5-lutidine and 64 g of Raney cobalt, and the air in the vessel was replaced with hydrogen gas, after which the internal temperature was raised to 240° C. Next, 570 g of methanol was continuously introduced thereinto under pressure by means of a constant volume delivery pump over a period of 7 hours. During the introduction of methanol, the produced gas was intermittently liberated outside the reaction system so as to keep the internal pressure of the autoclave in the range of 45 to 60 kg/cm2. After the reaction was completed, the autoclave was cooled to room temperature, and the contents were taken out. The catalyst was removed by filtration, after which 30 g of sodium hydroxide was added to the filtrate, and the resulting mixture was separated by using a separating funnel to obtain 400 g of an oily substance. When the oily substance obtained was distilled by using a Dixon packed tower, there were obtained 32 g of 3,5-lutidine of 99% purity as measured by gas chromatography at a tower top temperature of 90° to 93° C./50 mmHg, 314,4 g of 2,3,5-collidine of 99.3% purity as measured by gas chromatography at a tower top temperature of 102° to 103° C./50 mmHg, and 13.9 g of 2,3,5,6-tetramethylpyridine of 99% purity as measured by gas chromatography at a tower top temperature of 112° C./50 mmHg. The yield of the product 2,3,5-collidine obtained from 3,5-lutidine used as a starting material was 86%, and that of 2,3,5,6-tetramethylpyridine obtained therefrom was 3.4%. The selectivities of the above-mentioned products were 96.3% and 3.7%, respectively.

1. customas measured by gas chromatography at a tower top temperature of 112° C./50 mmHg