Hydroxylamine salts prodn. useful in caprolactam mfr. - by redn. of nitrogen mon:oxide in presence of 1-3C satd. hydrocarbon and noble metal catalyst

摘要

Hydroxylamine salt (I) is made by reducing NO with H2 in presence of a 1-3C satd. hydrocarbon and a noble metal catalyst, and recirculating part of the nitrogen monoxide and N2O-contg. gas from the reaction zone. The hydrocarbon is pref. used in an amt. such that the gas mixt. in the reaction zone contains 1-80 vol.% of the hydrocarbon. The total press. in the reaction zone is esp. 4-35 bar. The redn. is pref. carried out in phosphoric acid medium using a mol.ratio H2:NO of 7.5:1 to 20:1. Redn. is carried out e.g. at 25-90 deg.C. Use of hydrocarbons as inert medium in place of the usual inert gases allows use of higher partial pressures of NO and H2, and H2 obtd. by cracking of methane can be used in place of pure H2 used in previous processes. The hydroxylamine salt prods. are useful for the prodn. of caprolactam (monomer for nylon 6) via cyclohexane oxime.