Monoethers of polyoxyalkylene glycols are prepared by introducing a substantially water-free and aldehyde-free mixture of ethylene oxide and 1 : 2-propylene oxide into a heated liquid body of an aliphatic monohydroxy alcohol or an aliphatic monoether of an alkylene glycol under substantially anhydrous conditions, said oxides being present in said mixture in a ratio of ethylene oxide to propylene oxide such that more than 50 per cent by weight is propylene oxide, continuing the introduction of said mixture at a rate to maintain an amount of unreacted oxides at a substantially uniform concentration in the reaction mixture, until at least <FORM:0616256/IV(a)/1> parts by weight of oxides have reacted for each part by weight of the alcohol or mono-ether, where m is the molecular weight of said alcohol or ether, thereafter if necessary, stripping the resulting product of volatile materials to obtain a residue having an average molecular weight of at least 500. The process is preferably effected by dispersing in the alcohol an amount of a catalyst comprising an alkaline material, such as an alkali metal hydroxide or alcoholate, or boron trifluoride with or without calcium oxide and introducing the oxide mixture at a temperature between 80 DEG and 160 DEG C. to maintain a gauge pressure of between 5 and 200 lbs. per sq. inch. After neutralisation and removal of the catalyst, the crude product may be stripped. The product may be purified to remove water-soluble impurities, before or after stripping, by an extraction step using water or an aqueous alkaline solution as the extractant, separation of the aqueous extract being facilitated by heating, salting out or by carrying out the extraction in the presence of a water-immiscible solvent for the desired product, and preferably, by treating the solution with successive small portions of water. The products may be used as lubricants and pressure transmitting media. In examples: (1) butanol containing sodium butylate dispersed therein is reacted with a 1 : 3 ratio mixture of ethylene oxide and propylene oxide at 106 DEG -118 DEG C. and a pressure of up to 35 lbs. gauge; part of the crude product is reacted with more of the oxide mixture and a portion of this product is diluted with water, neutralised with carbon dioxide, hot water extracted, stripped at 180 DEG C. under reduced pressure and again washed yielding a product of mol. p weight ca. 520 whilst another portion is treated with more oxide and the resulting product again divided and repeatedly worked up similarly to yield a series of products having molar weights ranging up to 1900; (2) a number of similar products are obtained as in (1) the oxide mixture comprising 10 parts ethylene oxide per 90 parts propylene oxide. Tables and graphs illustrating various of the physical properties of these ether glycols are given. Reference is made to the use of monohydric alcohols having from 1 to 14 carbon atoms and monoaliphatic ethers of ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol as additional starting materials. Specification 584,367 is referred to. The Specification as open to inspection under Sect. 91 includes the preparation of monoethers by the reaction of a mixture of ethylene oxide and 1,2-propylene oxide, containing at least a slight preponderance by weight of the latter, with an aliphatic monohydroxy alcohol under substantially anhydrous conditions and recovery of a mixture of monoethers having an average molecular weight of at least 332 of which at least 300 is attributable to the oxyalkylene groups therein. It also includes substantially the whole of the subject matter of Specification 584,367, together with additional examples illustrating the reaction of butanol with 75 : 25, 60 : 40 and 50 : 50 ethylene oxide-propylene oxide mixtures and of methanol and tetradecanol with the 50 : 50 oxide mixture. This subject-matter does not appear in the Specification as accepted.ALSO:Mono-ethers of polyoxyalkylene glycols are prepared by introducing a substantially water-free and aldehyde-free mixture of ethylene oxide and 1 : 2-propylene oxide into a heated liquid body of an aliphatic monohydroxy alcohol or an aliphatic mono-ether of an alkylene glycol under substantially anhydrous conditions, said oxides being present in said mixture in a ratio of ethylene oxide to propylene oxide such that more than 50 per cent by weight is propylene oxide, continuing the introduction of said 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 the alcohol or mono-ether, where m is the molecular weight of said alcohol or ether thereafter, if necessary, stripping the resulting product of volatile materials to obtain a residue having an average molecular weight of at least 500. The process is preferably effected by dispersing in the alcohol an amount of a catalyst comprising an alkaline material, such as an alkali metal hydroxide or alcoholate, or boron trifluoride with or without calcium oxide and introducing the oxide mixture at a temperature between 80 DEG and 160 DEG C. to maintain a gauge pressure of between 5 and 200 lbs. per sq. inch. After neutralization and removal of the catalyst, the crude product may be stripped. The product may be purified to remove water-soluble impurities, before or after stripping, by an extraction step using water or an aqueous alkaline solution as the extractant, separation of the aqueous extract being facilitated by heating, salting out or by carrying out the extraction in the presence of a water-immiscible solvent for the desired product and, preferably, by treating the solution with successive small portions of water. The products may be used as lubricants and pressure-transmitting media. In examples: (1) butanol containing sodium butylate dispersed therein is reacted with a 1 : 3 ratio mixture of ethylene oxide and propylene oxide at 106-118 DEG C. and a pressure of up to 35 lbs. gauge; part of the crude product is reacted with more of the oxide mixture and a portion of this product is diluted with water, neutralized with carbon dioxide, hot water extracted, stripped at 180 DEG C. under reduced pressure and again washed, yielding a product of mol. weight ca. 520 whilst another portion is treated with more oxide and the resulting product again divided and repeatedly worked up similarly to yield a series of products having molar weights ranging up to 1900; (2) a number of similar products are obtained as in (1), the oxide mixture comprising 10 parts ethylene oxide per 90 parts propylene oxide. Tables and graphs illustrating various of the physical properties of these ether glycols are given. Reference is made to the use of monohydric alcohols having from one to 14 carbon atoms and mono-aliphatic ethers of ethylene glycol, diethylene glycol, propylene glycol and dipropylene glycol as additional starting materials. Specification 584,367 is referred to. The Specification as open to inspection under Sect. 91 includes the preparation of mono-ethers by the reaction of a mixture of ethylene oxide and 1,2-propylene oxide, containing at least a slight preponderance by weight of the latter, with an aliphatic monohydroxy alcohol under substantially anhydrous conditions and recovery of a mixture of mono-ethers having an average molecular weight of at least 332, of which at least 300 is attributable to the oxyalkylene groups therein. It also includes substantially the whole of the subject-matter of Specification 584,367, together with additional examples illustrating the reaction of butanol with 75 : 25, 60 : 40 and 50 : 50 ethylene oxidepropylene oxide mixtures and of methanol and tetradecanol with the 50 : 50 oxide mixture. This subject-matter does not appear in the Specification as accepted.