GB1397941A - Separation of amines - Google Patents

Abstract

1397941 Separating monofrom di-isopropylamine IMPERIAL CHEMICAL INDUSTRIES Ltd 10 Jan 1973 [24 Jan 1972] 3244/72 Heading C2C Mono- and di-isopropylamine are separated from a reaction stream containing these amines and acetone (e.g. derived from the reaction of isopropanol and ammonia) in two successive sequences of operations wherein in the first sequence (a) the reaction stream is fed via line 10 to a first distillation column 3 from which pure mono-isopropylamine is removed overhead and the bottom product is passed via line 12 to a second distillation column 4, from which (b) acetone and the remaining monoisopropylamine is removed overhead and the bottoms product comprising di-isopropylamine and water is passed to a third distillation column 5, from which (a) a mixture of water and di-isopropylamine is removed overhead and passed to a store 6 whilst the bottoms product, e.g. comprising isopropanol, water and a small amount of di-isopropylamine may be sent to a stripper and in the second sequence (d) bottoms product from the first distillation column 3 is prevented from passing to the second distillation column 4 (e.g. by passing it to a stripper or recycling or by stopping the production of fresh product), (e) the mixture of di-isopropylamine and water from the store 6 is passed to a phase separator 6 from which the fraction containing the major proportion of di-isopropylamine is fed to the second distillation column 4 and (f) substantially pure di-isopropylamine is removed as a side-stream from the column 4 via line 21. The mixture fed to the first distillation column 3 may be derived from the reaction mixture of a reactor 1 which has first been distilled in a column 9 to remove unreacted ammonia as overheads. The overhead product from the distillation column 4 in the first sequence of operations, comprising acetone, mono-isopropylamine and a small amount of di-isopropylamine may be recycled to the reactor 1. The overhead stream from the column 4 in the second sequence, which comprises a di-isopropylamine/water azeotrope may be passed to the phase separator 7.