| 摘要 |
<p><PICT:0897473/III/1> <PICT:0897473/III/2> Apparatus for the production of 2,21-dipyridyl comprises in Figs. 1 and 2 a boiler 3 opening into an insulated casing 5 which in turn opens into a condenser 6 open to the atmosphere. In Fig. 1 a liquid-permeable sintered glass disc 8 extends across a tubular reaction vessel 7 which rest coaxially within 5; a side tube 9 opens into the space between 8 and the end of 7 to extend upwardly along part of the length of 7; Raney nickel catalyst 10 covered by pyridine 11 is placed in 7 to rest on 8. In operation a further quantity of pyridine 12 is boiled in 3, the vapour passes up through 5 to the condenser 6 in which it condenses and falls back through 7; some of the pyridine is forced through the catalyst 10 and the reaction products together with unreacted pyridine are forced upwardly through 9 and fall back into 3. In Fig. 2 a tube 13 closed at the lower end rests within 5 and is partially filled with catalyst 14 and then filled up with pyridine 15; a funnel 16 is inserted axially into 14; the pyridine 12 is boiled in 3 and the vapour passes up to 6 where it condenses and falls back into 16; some of the pyridine is forced through the catalyst where it reacts and the 2,21-dipyridyl and unreacted pyridine are carried into 3.ALSO:2,21-Dypyridyl is produced by maintaining Raney nickel in contact with pyridine at elevated temperatures, the products including 2,21-dipyridyl being removed from contact with the catalyst continuously or intermittently by displacement with pyridine. The unreacted pyridine may be separated from the product, e.g. by distillation, and recycled to the reactor. Preferably the pyridine in contact with the catalyst is maintained at temperatures above 80 DEG C. The process may be carried out, for example, by percolating pyridine near its boiling point through a porous bed of dry Raney nickel catalyst so that the 2,21-dipyridyl is continuously removed by displacement by pyridine or the liquid pyridine near its boiling point is passed upwardly through a bed of catalyst so that the 2,21-dipyridyl and the unreacted pyridine overflow from the top of the receptacle containing the catalyst. Details of the apparatus for carrying out the process are given.</p> |
