GB610505A - A method for making polyoxyalkylene glycols - Google Patents

Abstract

Lubricants comprise polyoxyalkylene glycols containing both the oxyethylene and oxy-1 : 2-propylene radicals and having an average molecular weight of at least 500 which are prepared from ethylene, propylene and butylene glycols or their dimers and trimers and a mixture of ethylene oxide and propylene oxide by reaction according to specified conditions (see Group IV (b)). They may be used as lubricants for metal surfaces, textile fibres such as wool, cotton, flax and hemp and synthetic fibres and rubber, either alone, in aqueous solution, or with viscosity-reducing diluents such as glycol ethers. When the glycol products are refined by water washing, the aqueous extract may be stripped to yield lower molecular weight glycols which may also be used as lubricants. Examples are given of products derived from diethylene glycol.ALSO:Polyoxyalkylene glycols having a polyalkylene chain containing both the oxyethylene and oxy-1 : 2-propylene radicals are prepared by introducing a mixture (containing less than 0.1 per cent by weight of water and of aldehyde) of ethylene oxide and 1 : 2-propylene oxide into a heated liquid body of a lower alkylene glycol, the oxides being present in said mixture in a ratio of from (a) 75 per cent by weight of ethylene oxide to 25 per cent by weight of propylene oxide to (b) 25 per cent by weight of ethylene oxide to 75 per cent by weight of propylene oxide, continuing the introduction of said oxide mixture at a rate to maintain an amount of unreacted oxides at a substantially uniform concentration in the reaction mixture, until at least 500 - m/m parts by weight of oxides have reacted for each part by weight of glycol employed, where m is the molecular weight of said glycol, and thereafter stripping the resulting product of volatile materials to obtain a residue having an average molecular weight of at least 500. The glycols which may be used are ethylene, propylene and butylene glycols and their dimers and trimers. The glycols may be formed in situ from the corresponding alkylene oxides and water. The process of the invention may be carried out in a closed system at 50 DEG to 160 DEG C. under a uniform pressure of the oxide mixture of up to 200 lbs./sq. in. and, preferably, in the presence of a catalyst comprising sodium or potassium hydroxide or glycollate, boron trifluoride, trimethyl hydroxyethyl ammonium hydroxide or morpholine and the catalyst may be added portion-wise. The presence of gaseous oxygen should be avoided. Generally, the reaction product is treated to destroy the catalyst and is then subjected to a washing treatment to extract water-soluble impurities including low molecular weight ether-glycols before being stripped to remove low boiling substances. Washing may be effected with water or aqueous salt solutions-separation of the aqueous extract phase is facilitated by heating, salting out or by carrying out the washing in the presence of a water-immiscible solvent for the desired product, for example butanol, benzene, ethylene chloride or dichlordiethyl ether, such washing preferably being effected using the water portion-wise. The polyoxyalkylene glycols may have an average molecular weight of from 500 to 10,000 and may be used as lubricants (see Group III) and hydraulic fluids. In typical examples: (1) a quantity of mixed ethylene and propylene oxides (3 : 1 weight ratio) is passed progressively into diethylene glycol under pressure in the presence of sodium hydroxide with agitation and part of the resulting product reacted as before with a further quantity of the oxide mixture; a portion of the final product is neutralized with sulphuric acid and its average M.W. found to be 1060; (2) a portion of the unneutralized final product of (1) is itself reacted with more of the oxide mixture as above and part is neutralized and its M.W. determined to be 2720, whilst (3) a further portion is again reacted yielding a glycol of M.W. 4210; (6) diethylene glycol is similarly reacted in the presence of sodium hydroxide with a mixture of ethylene and propylene oxides (3 : 1), the product neutralized with carbon dioxide and then stripped under reduced pressure yielding a residue of M.W. 636; further examples are described wherein diethylene glycol is reacted with oxide mixtures containing the respective oxides in 50 : 50 and 25 : 75 weight ratios according to the method of (1)-(3) above yielding a similar series of products which are worked up as in (1) or by neutralization followed by repeated water washing of hot solutions of the products in dichlordiethyl ether, the solvent layer and extract phase both being stripped to leave residues comprising glycol ethers whose properties are described.ALSO:Polyoxyalkylene glycols having a polyalkylene chain containing both the oxyethylene and oxy-1 : 2-propylene radicals are prepared by introducing a mixture (containing less than 0.1 per cent by weight both of water and of aldehyde) of ethylene oxide and 1 : 2-propylene oxide into a heated liquid body of a lower alkylene glycol, the oxides being present in said mixture in a ratio of from (a) 75 per cent by weight of ethylene oxide to 25 per cent by weight of propylene oxide to (b) 25 per cent by weight of ethylene oxide to 75 per cent by weight of propylene oxide, continuing the introduction of said oxide mixture at a rate to maintain an amount of unreacted oxides at a substantially uniform concentration in the reaction mixture, until at least 500 - m/m parts by weight of oxides have reacted for each part by weight of glycol employed, where m is the molecular weight of said glycol, and thereafter if necessary stripping the resulting product of volatile materials to obtain a residue having an average molecular weight of at least 500. The glycols which may be used are ethylene, propylene and butylene glycols and their dimers and trimers. The glycols may be formed in situ from the corresponding alkylene oxides and water. The process of the invention may be carried out in a closed system at 50 DEG to 160 DEG C. under a uniform pressure of the oxide mixture of up to 200 lbs./sq. in. and, preferably, in the presence of a catalyst comprising sodium or potassium hydroxide or glycollate, boron trifluoride, trimethyl hydroxyethyl ammonium hydroxide or morpholine and the catalyst may be added portionwise. The presence of gaseous oxygen should be avoided. Generally, the reaction product is treated to destroy the catalyst and is then subjected to a washing treatment to extract water-soluble impurities including low molecular weight ether-glycols before being stripped to remove low boiling substances. Washing may be effected with water or aqueous salt solutions; separation of the aqueous extract phase is facilitated by heating, salting out or by carrying out the washing in the presence of a water-immiscible solvent for the desired product, for example, butanol, benzene, ethylene chloride or dichlordiethyl ether, such washing preferably being effected using the water portionwise. Lower ether-glycols in the aqueous extract may be recovered. It is stated that oxides of the desired purity for use in the process may be obtained by distilling the oxides from solution in a hygroscopic glycol, by scrubbing with such a glycol or by passing the oxides over solid caustic soda or potash. The polyoxyalkylene glycols may have an average molecular weight of from 500 to 10,000 and may be used as lubricants (see Group III) and hydraulic fluids. In typical examples: (1) a quantity of mixed ethylene and propylene oxides (3 : 1 weight ratio) is passed progressively into diethylene glycol under pressure in the presence of sodium hydroxide with agitation and part of the resulting product reacted as before with a further quantity of the oxide mixture; a portion of the final product is neutralized with sulphuric acid and its average M.W. found to be 1060; (2) a portion of the unneutralized final product of (1) is itself reacted with more of the oxide mixture as above and part is neutralized and its M.W. determined to be 2720, whilst (3) a further portion is again reacted yielding a glycol of M.W. 4210; (6) diethylene glycol is similarly reacted in the presence of sodium hydroxide with a mixture of ethylene and propylene oxides (3 : 1), the product neutralized with carbon dioxide and then stripped under reduced pressure yielding a residue of M.W. 636; further examples are described wherein diethylene glycol is reacted with oxide mixtures containing the respective oxides in 50 : 50 and 25 : 75 weight ratios according to the method of (1)-(3) above, yielding a similar series of products which are worked up as in (1) or by neutralization followed by repeated water washing of hot solutions of the products in dichlordiethyl ether, the solvent layer and extract phase both being stripped to leave residues comprising glycol ethers whose properties are described.