GB893809A - Improvements in the separation of mixtures which contain a non-volatile complex catalyst - Google Patents

Abstract

Mixtures, resulting from the synthesis of alcohols (from olefins, CO and H2O or of amines) (when part of the H2O is replaced by NH3 or primary or secondary amines), and containing a non-volatile complex catalyst formed by the reaction of an iron carbonyl, an amine, and H2O, are separated by treating with a stream of CO at elevated temperature to effect decomposition of the complex, removing condensable compounds from the CO stream, and rectifying the remaining mixture after recovery of the bulk of the iron as pentacarbonyl. The complex may be prepared from Fe(CO)4 or Fe(CO)6, and trimethylamine, N-butyl diethanolamine, pyrrolidine, piperidine, N-butyl piperidine, N-methyl pyrrolidine, or N-butyl-(3)-hydroxypyrrolidine. A nitrile, isonitrile, lactam, or sulphur compound containing a thioether bridge, or mixtures thereof (e.g. capronitrile, benzonitrile, adiponitrile, N-methyl pyrrolidone, caprolactam, caprylic lactam, thiodiglycol, or thiodibutyric acid) may be present in the complex-forming reaction mixture. The CO treatment may be at 70-130 DEG C. and atmospheric to 40 atmospheres. The Fe (CO)5 is separated from the other condensable constituents of the gas stream, which latter may be returned to the CO treatment. Thus, the gases may be passed up a column countercurrent to a reflux of the other condensable constituents, Fe(CO)5 separated from the condensate by decantation, and remaining gas returned to the reaction chamber. The CO may be mixed with inert gas, e.g. N2 or H2. After removal of Fe(CO)5 an aqueous base, e.g. caustic soda, may be added to the remaining mixture, before fractional distillation, to isolate acids. Syntheses referred to are propanol from ethylene, and butanol from propylene.ALSO:Mixtures, resulting from the synthesis of alcohols from olefins, CO, and H2O or of amines when part of the H2O is replaced by NH3 or primary or secondary amines, which contain a non-volatile complex catalyst formed by the reaction of an iron carbonyl, an amine, and H2O, are separated by treating with a stream of CO at elevated temperature of effect decomposition of the complex, removing condensable compounds from the CO stream, and rectifying the remaining mixture after recovery of the bulk of the iron as pentacarbonyl. The complex may be prepared from Fe(CO)4 or Fe(CO)6, and trimethylamine, N-butyl diethanolamine, pyrrolidine, piperidine, N-butyl piperidine, N-methylpyrrolidine, or N-butyl-(3)-hydroxy-pyrrolidine. A nitrile, isonitrile, lactam, or sulphur compound containing a thioether bridge, or mixtures thereof, e.g. capronitrile, benzonitrile, adiponitrile, N-methyl pyrrolidone, caprolactam, caprylic lactam, thiodiglycol, or thiodibutyric acid may be present in the complex-forming reaction mixture. The CO treatment may be at 70 DEG C.-130 DEG C. and atmospheric to 40 atmospheres. The Fe (CO)5 is separated from the other condensable constituents of the gas stream, which latter may be returned to the CO treatment. Thus, the gases may be passed up a column countercurrent to a reflux of the other condensable constituents, Fe(CO)5 separated from the condensate by decantation, and remaining gas returned to the reaction chamber. The CO may be mixed with inert gas, e.g. N2 or H2. After removal of Fe(CO)5 an aqueous base, e.g. caustic soda, may be added to the remaining mixture, before fractional distillation, to isolate acids. Syntheses referred to are propanol from ethylene, and butanol from propylene.