Heterogeneous conversion of acyclic compounds to pyridine bases - a review

摘要: Abstract A large and growing demand for the derivatives of pyridine exists because their many chemical, pharmaceutical agricultural uses. The commercial products are derived from bases, which can be prepared by heterogeneous gas-phase cyclisation simple organic molecules in presence ammonia. Alumino-silicates catalytically active conversion carbonyl compounds to bases. It is probable that reactants adsorbed at acidic sites formation imines precedes cyclisation. catalysts, with exception certain zeolites, lose activity prolonged use, probably as a result consecutive reactions lead blocking narrow pore openings. Alkenes converted bases two stages: partial oxidation over mixed-metal oxide, followed ammonia alumino-silicates. Alternatively, direct ammoxidation achieved using catalysts based on Te Al Si O. These retain during but limited lack selectivity. Potential new routes include conversions alkynes, epoxides alcohols. Metal phosphates both alkynes epoxides. former process may involve tautomeric intermediates. most recent innovation condensation aliphatic alcohols ammonia, zeolitic catalyst.