Ammonia → 3,3-Dimethylpiperidine

Participants

Reaction Steps

34.0 g per hour of 2,2-dimethyl-4-cyanobutanal (purity 93.4%, 31.8 g, 0.254 mol) and 1450 ml (870 g, 51.1 mol) per hour of liquid ammonia were pumped at 250 bar and 60° C. through a tubular reactor (diameter 16 mm, fill level 50 cm, oil-heated twin jacket) upstream of the hydrogenation reactor and filled with 63.5 g (100 ml) of TiO2 (anatase) in the form of 1.5 mm pellets. The discharge from the reactor was subsequently passed through the hydrogenation reactor from bottom to top at 250 bar and 120° C. while simultaneously passing 100 l (S.T.P.)/h (4.5 mol) of hydrogen through the reactor. The product stream was decompressed to atmospheric pressure and NH3 was removed by distillation. The product from 32.4 hours was separated by fractional distillation on a 30 cm packed column (3 mm glass rings), giving 344.8 g of 3,3-dimethylpiperidine (b.p. 50°-52° C./210 mmHg) and 753.6 g of 2,2-dimethylpentane-1,5-diamine (b.p.=72° C./8 mmHg). The diamine yield was 70.5% of theory.

Provenance & Evidence