Patent GB-651712-A (GB)
Title: Mixtures of polyoxyalkylene diols and methods of making such mixtures
IPC: C08G65/26
Filed: 1946-04-16
Abstract: Polyoxyalkylene glycols are prepared by introducing a mixture of ethylene oxide and propylene oxide, containing more than 3 parts by weight of propylene oxide per part of ethylene oxide and containing not more than 0.1 per cent by weight of either water or aldehyde, into a heated liquid body of an alkylene glycol, 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:0651712/IV (a)/1> parts by weight of oxides have reacted per part alkylene glycol employed, m being the molecular weight of the glycol, and thereafter, if necessary, stripping the resultant product to obtain a residue having an average molecular weight of at least 500.  The reaction is generally carried out at an elevated temperature below 160 DEG  C. and at between 5 and 200 lbs. gauge pressure.  Alkaline condensation catalysts, especially sodium or potassium hydroxide or glycollate, are normally employed and in an amount of 0.2 to 1 per cent of the total weight of reactants; the catalyst is preferably added in increments.  A portion of the oxide mixture may be reacted with all of the glycol and the resulting intermediate product of relatively low molecular weight is then reacted with the remainder of the oxides.  Ethylene and propylene glycols, their dimers or trimers and butylene glycol are specified starting materials.  The glycols may be formed in situ by reacting the corresponding oxides with water.  The oxyalkylene glycols may have molecular weights of up to 10,000 or 20,000. They may be utilized, in conjunction with non-aqueous viscosity-reducing diluents or alone, as lubricants.  The properties of the products are illustrated by graphs. Specification 610,505 is referred to.  The Specification as open to inspection under Sect. 91 relates to the preparation of polyoxyalkylene glycols by reaction of an alkylene glycol with a mixture of ethylene and propylene oxides, containing at least 3 parts by weight of propylene oxide per part of ethylene oxide, the product having an average molecular weight of at least 300 attributable to the oxyethylene and oxypropylene groups in the molecule.  This subject-matter does not appear in the Specification as accepted.ALSO:Polyoxyalkylene glycols containing a polyoxyalkylene chain having both the oxyethylene and 1 : 2-oxypropylene radicals are prepared by introducing a mixture (containing not more than 0.1 per cent by weight of either aldehyde or water) of ethylene oxide and 1 : 2-propylene oxide into a heated liquid body of an alkylene glycol, said oxides being present in said mixture in a ratio of more than 3 parts by weight of propylene oxide per part of ethylene 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 per part alkylene glycol employed, m being 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 reaction is generally carried out at an elevated temperature below 160 DEG  C. and at between 5 and 200 lbs. gauge pressure.  An alkaline condensation catalyst, preferably consisting of sodium or potassium hydroxide which may be used in the form of the corresponding glycollate, is present; an amount of from 0.2 to 1 per cent of the total weight of reactants appearing in the final product is employed; desirably, it is added in increments to the reaction mixture.  A portion of the oxide mixture may be reacted with all of the alkylene glycol to form an intermediate product of relatively low molecular weight which is then reacted with the remainder of the oxide mixture to form a final product of the desired molecular weight. The alkylene glycols which maybe employed include ethylene and propylene glycols or their dimers or trimers and also butylene glycols.  If desired, the glycols may be formed in situ by reacting the corresponding alkylene oxide with water.  The products of the invention are complex mixtures whose individual constituents may differ in molecular weight and in the distribution of the oxyethylene and oxypropylene groups in the molecules; they may be used as lubricants and in lubricant compositions (see Group III).  In the example, an oxide mixture containing one part by weight ethylene oxide per nine parts of propylene oxide is introduced into propylene glycol containing some sodium hydroxide at a rate to maintain a pressure of not more than 50 lbs. per square inch at 110-120 DEG  C.; a part of the resulting product is reacted with a further amount of the same oxide mixture with the aid of more sodium hydroxide and part of the new resulting product is again reacted with yet more of the oxide mixture.  A portion of the product obtained is treated with carbon dioxide to neutralize the catalyst, washed with water and then stripped at elevated temperature giving a desired glycol composition of molecular weight 801.  Following the same procedure five more glycol compositions are produced utilizing part of the unneutralized product of one reaction as the starting material of the rest and compositions are prepared having average molecular weights ranging up to 4186.  Graphical illustrations are provided comparing the rate of change of viscosity with temperature of the products with those of similar products obtained by use of ethylene oxide-propylene oxide mixtures having oxide ratios different from those herein described especially the products described in Specification 610,505 to which reference is made.  The Specification as open to inspection under Sect. 91 relates to the preparation of polyoxyalkylene glycols by reaction of an alkylene glycol with a mixture of ethylene and propylene oxides, containing at least 3 parts by weight of propylene oxide per part of ethylene oxide, the product having an average molecular weight of at least 300 attributable to the oxyethylene and oxypropylene groups in the molecule.  This subject-matter does not appear in the Specification as accepted.ALSO:Lubricant compositions comprise the polyoxyalkylene glycols obtained by reacting a mixture of ethylene and propylene oxides, containing more than 3 parts by weight of propylene oxide per part of ethylene oxide with an alkylene glycol in specified manner (see Group IV (b)), and stripping the resulting product, if necessary, to obtain a residue having an average molecular weight of at least 500.  The polyoxyalkylene glycols may be used alone or in conjunction with non-aqueous viscosity diluents.  They may be used as crank-case lubricants or hydraulic liquids.  They have a lesser solubility for water at higher temperatures so that dissolved water may be separated out by merely heating the composition to a higher temperature.  In general, the polyoxyalkylene glycols may have molecular weights of up to p  10,000 or 20,000; an example illustrates products derived from propylene glycol and having molecular weights of up to 4186; glycol starting materials mentioned are ethylene and propylene glycols, their dimers and trimers and butylene glycol.  Graphs illustrating properties of the products are given.  Specification 610,505 is referred to.  The Specification as open to inspection under Sect. 91 states that the polyoxyalkylene glycols are those prepared by reacting an alkylene glycol with a mixture of ethylene and propylene oxides containing at least 3 parts by weight of propylene oxide per part of ethylene oxide, the product having an average molecular weight of at least 300 attributable to the oxy-ethylene and -propylene groups in the molecule.  This subject-matter does not appear in the Specification as accepted.