GB813957A - Process for the preparation of morpholine and piperazines - Google Patents

Abstract

Piperazines and morpholines are obtained by reacting a glycol of formula <FORM:0813957/IV (b)/1> or <FORM:0813957/IV (b)/2> in which R, R1 and R11 are hydrogen, alkyl or aryl radicals, R1 and R11 optionally forming a cycloalkyl group with the two carbon atoms to which they are attached, with ammonia in contact with hydrogen and a hydrogenation catalyst at elevated temperature and pressure. Suitable glycols for use as starting materials are, for example, ethylene glycol, propylene glycol, 1.2-butylene glycol, diethylene glycol, dipropylene glycol, di-1.2-butylene glycol, di-2.3-butylene glycol, cyclohexane-1.2-diol, phenylethylene glycol and hydrobenzoin. The process may be carried out at temperatures in the range 150-400 DEG C. and pressures in the range 30-400 atm. Suitable catalysts are, for example, copper, nickel, cobalt, chromium, molybdenum, manganese, platinum, palladium and rhodium and their oxides. They may be used in combination with normally non-reducible oxides such as chromium oxide (Cr2O3) molybdenum oxide (Mo2O3) and manganese dioxide (MnO2) and may be deposited on an inert support. Catalyst modifiers or stabilizers such as sodium and potassium sulphate may be deposited on the catalyst. Preferably a molar excess of ammonia is used and the process may be carried out batchwise or continuously. In the examples: (a) 1.2-propylene glycol is reacted with ammonia in the presence of ammonia and a copper oxide-nickel oxide-chromic oxide catalyst to give dimethyl morpholine; (b) propylene glycol is similarly reacted with ammonia to give dimethyl piperazine; (c) diethylene glycol is similarly reacted with ammonia to give morpholine; (d) 2.3-butylene glycol is reacted with ammonia in the presence of hydrogen and Raney nickel to give 2.3.5.6-tetramethyl piperazine; (e) dipropylene glycol is reacted continuously with ammonia in the presence of hydrogen and a nickel-copper-chromic oxide catalyst to give dimethyl morpholine; (f) ethylene glycol is reacted with ammonia as in (a) to give piperazine; (g) diethylene glycol is continuously reacted with ammonia in the presence of hydrogen and a copper-nickel-manganese oxide catalyst to give morpholine; and (h) diethylene glycol is reacted with ammonia in the presence of hydrogen and a nickel-copper-chromium catalyst to give morpholine.