GB736991A - The manufacture of polyoxyalkylene glycols and their mono-ethers - Google Patents

Abstract

<PICT:0736991/IV (a)/1> Polyoxyalkylene glycols or monoethers thereof containing at least four oxyethylene groups per molecule and having molecular weights up to 10,000 are formed by continuously passing a homogeneous liquid mixture of ethylene oxide, an alkali metal catalyst and an organic hydroxy compound through a reactor with an internal temperature of 50-190 DEG C. and a pressure sufficient to maintain the reactants in the liquid phase (e.g. 7-130 atmospheres), the contact time in the reactor being 5-60 minutes so that 25-97 per cent of the ethylene oxide reacts. Organic hydroxy compounds mentioned are ethylene glycol, propylene glycol, diethylene glycol and dipropylene glycol, polyoxyethylene and polyoxypropylene glycols with 3 or more oxyalkylene groups, n-butyl alcohol, lauryl alcohol, 2-ethyl hexanol, benzyl alcohol, ethylene glycol monomethyl ether, phenol, b -naphthol, di-isobutyl cresol, octyl phenol, oleyl alcohol, cresol and 2,21-thiodiethanol. The catalyst is sodium, potassium or lithium generally dissolved as hydroxide or alkoxide. The catalyst concentration is preferably 0.005-0.1 gram mols./litre of reactants. Impurities such as carbon dioxide, ethylene dichloride, acetaldehyde or acetic acid are removed from the reactants; thus the ethylene oxide may be passed to the reaction zone through a bed of solid caustic soda or potash. In a preferred embodiment, the hydroxy body is mixed with the catalyst, traces of water or methanol are removed by vacuum and the mixture fed by pump 11 and supply line 13 to join the ethylene oxide fed by pump 12 and supply line 14 in orifice mixer 17. The reaction mixture passes to stainless steel reactor coil 19 surrounded in vessel 20 by liquid 21 maintained boiling by heater 23 in reboiler 22 under reflux condenser 24. Inert gas, e.g. nitrogen, may be fed through pipe 33 and vent pipe 34 into vessel 20. The boiling liquid may be water, ethylene glycol, or ethylene glycol monobutyl ether or blends thereof. The reacted mixture leaves coil 19 by pipe 25 and needle let-down valve 26 and passes by pipe 27 to stripping still 28 whence unreacted ethylene oxide is removed for recycling, and the product is pumped by pump 29 and pipe 30 to cooler 31 for storage or further treatment, viz. neutralization of alkali, and filtration. Products which are monoethers may be esterified, e.g. the product from ethylene glycol monomethyl ether and ethylene oxide was esterified with lauric or palmitic acid. The Specification includes a number of specified examples of the preparation of particular polymers.ALSO:<PICT:0736991/IV (b)/1> Polyoxyalkylene glycols or monoethers thereof containing at least four oxyethylene groups and having molecular weights up to 10,000 are formed by continuously passing a homogeneous liquid mixture of ethylene oxide, an alkali metal catalyst and an organic hydroxy compound through a reactor with an internal temperature of 50-190 DEG C. and a pressure sufficient to maintain the reactants in the liquid phase (e.g. 7-130 atmosphere) the contact time in the reactor being 5-60 minutes so that 25-97 per cent of the ethylene oxide reacts. Organic hydroxy compounds mentioned are ethylene glycol, propylene glycol, diethylene glycol and dipropylene glycol, polyoxyethylene and poloxypropylene glycols with 3 or more oxyalkylene groups, n-butyl alcohol, lauryl alcohol, 2-ethyl hexanol, benzyl alcohol, ethylene glycol monomethyl ether, phenol, b -naphthol, diisobutyl cresol, octyl phenol, oleyl alcohol, cresol and 2,21-thiodiethanol. The catalyst is sodium, potassium or lithium generally dissolved as hydroxide or alkoxide. The catalyst concentration is preferably 0.005-0.1 gram mols/litre of reactants. Impurities such as carbon dioxide, ethylene dichloride, acetaldehyde or acetic acid are removed from the reactants; thus the ethylene oxide may be passed to the reaction zone through a bed of solid caustic soda or potash. In a preferred embodiment, the hydroxy body is mixed with the catalyst, traces of water or methanol are removed by vacuum and the mixture fed by pump 11 and supply line 13 to join the ethylene oxide, fed by pump 12 and supply line 14, in orifice mixer 17. The reaction mixture passes to stainless steel reactor coil 19 surrounded in vessel 20 by liquid 21 maintained boiling by heater 23 in reboiler 22 under reflux condenser 24. Inert gas, e.g. nitrogen may be fed through pipe 33 and vent pipe 34 into vessel 20. The boiling liquid may be water, ethylene glycol or ethylene glycol monobutyl ether, or blends thereof. The reacted mixture leaves coil 19 by pipe 25 and needle let-down valve 26 and passes by pipe 27 to stripping still 28 whence unreacted ethylene oxide is removed for recycling, and the product is pumped by pump 29 and pipe 30 to cooler 31 for storage or further treatment, viz. neutralization of alkali, and filtration. Products which are monoethers may be esterified, e.g. the product from ethylene glycol monomethyl ether and ethylene oxide was esterified with lauric or palmitic acid. The Specification includes a number of specific examples of the preparation of particular polymers.