Abstract: A single-stage method for producing &agr;-hydroxy ethers by oxidizing olefinic substrates with organic hydroperoxides and opening the resultant oxirane ring by means of monovalent or polyvalent alcohols wherein a molybdenum compound in combination with a compound selected from the group consisting of boron trifluoride, aluminum oxides, 1,8-diazabicyclo-[5.4.0]-undec-7-ene or 1,4-diazabicyclo-[2.2.2]-octane, and mixtures thereof is used as a catalyst system.

Abstract: A method for the production of polyetherols using aluminum phosphonate catalysts is disclosed. Reaction products of the process include various polyetherols including very low unsaturation polyether polyols. The aluminum phosphonate catalyst preferably has a general structure of RPO-(OAlR′R″)2, wherein O represents oxygen, P represents pentavalent phosphorous, Al represents aluminum, R comprises a hydrogen, an alkyl group, or an aryl group, and R′ and R″ independently comprise a halide, an alkyl group, an alkoxy group, an aryl group, or an aryloxy group. Polyols produced according to the disclosed procedure have properties very similar to or more beneficial than those produced utilizing the typical base catalysts.

Abstract: A process for preparing amphiphilic compounds having at least two hydrophilic and at least two hydrophobic groups by reacting an olefinic substrate having at least two double bonds with an organic hydroperoxide to form an oxirane ring, opening, the oxirane ring with an alcohol in the presence of a catalyst system comprising a molybdenum compound as a first catalyst component and a second catalyst component selected from the group consisting of boron trifluoride, alumina, 1,8-diazzabicyclo-(5.4.0)-undec-7-ene, 1,4-diazabicyclo-(2,2,2)-octane.

Abstract: The present invention relates to a polyethylene glycol-bound ligand in which polyethylene glycol is bound to a ligand having a binding affinity for a specific receptor or a specific protein (i.e.

Abstract: A process to obtain fluoropolyoxyalkylenes having the structure: T—O—(CF2CF(CF3)O)n−1—(CF(CF3)O)m—CF2—CH2OH  (I) wherein: T=C1-C3 perfluoroalkyl containing one Cl atom; n=an integer from 1 to 15; m/n=0-0.5, m+n such to have a number molecular weight in the range 280-4,000; said process comprising: a) the gradual addition of a metal hydride in admixture with a solvent to an ester precursor having the structure T—O—(CF2CF(CF3)O)n−1—(CF(CF3)O)m—CF2—COOR  (II)  wherein R=C1-C20 alkyl, or aromatic, cycloalkyl or heterocyclic residue, b) the hydrolysis of the reaction mixture obtained in step a) with an aqueous acid solution, the subsequent separation from the obtained organic phase of the compounds of structure (I).

Abstract: A method for producing a polyoxyalkylene polyol which comprises subjecting propylene oxide and ethylene oxide to ring-opening addition polymerization with an initiator in the presence of a catalyst,

Abstract: A process for preparing polyetherols by ring-opening polymerization of alkylene oxides onto H-functional initiator molecules, which comprises at least one process step a) in which a compound of the formula (I)

Abstract: The present invention relates to a process for the preparation of polyether polyols by the reaction of alkylene oxides and compounds containing active hydrogens, in the presence of specific Lewis acid metal compounds as catalysts, novel bis(perfluoroalkylsulfonic acid) compounds of Group 13 of the Periodic Table of the Elements, and to a process for the preparation thereof and the use thereof as catalysts for ring-opening polymerization of cyclic ethers.

Abstract: Polyetherols based on solid initiator substances and liquid, hydroxyl-containing coinitiators are prepared by a catalyzed addition reaction of alkylene oxides by a process in which the initiator combination contains diols carrying ethoxy structures, the ratio of the average number of hydroxyl groups per mole of initiator combination to the number of ethoxy structures in the polyetherol being from 1:0.2 to 1:1.8 and the ratio of the amounts by weight of the diols carrying ethoxy structures to the average molecular weight of the polyetherol being from 1:2 to 1:15. The polyetherols prepared by this process are used for the preparation of PUR, in particular, rigid PUR foams.

Abstract: The present invention relates to a process for the alkoxylation of organic compounds comprising the reaction of at least one organic compound with at least one alkoxylating agent in the presence of a catalyst system, wherein a polyetheralcohol is obtained, characterized in that the catalyst system comprises a metallo organic framework material comprising pores and at least one metal ion and at least one at least bidentate organic compound, which is coordinately bounded to said metal ion, and polyurethanes or polyurethane foams, which are obtainable by using a prepared polyether alcohol as a starting material.

Abstract: A process for preparing polyoxyalkylene polyether products, which process comprises (i) reacting starter and alkylene oxide in the presence of a double metal cyanide complex catalyst while mixing, and (ii) reacting in a pipe reactor the mixture obtained in step (i) to obtain a polyoxyalkylene polyether product comprising substantially no alkylene oxide, and (iii) removing the product of step (ii) from the process.

Abstract: A process for preparing polyetherols by ring-opening polymerization of alkylene oxides onto H-functional initiator molecules comprises at least one process step a) in which a compound of the formula (I) M′aM″b(OH)cOd* Ae*Lf  (I), is applied to a solid inert support or incorporated in the latter or molded to form a shaped body is used as catalyst, and at least one process step b) in which a multimetal cyanide compound of the formula (II) M1a[M2(CN)b(A)c]d·fM1gXn·h(H20) eL  (II) is applied to a solid, inert support or incorporated in the latter or molded to form a shaped body or in powder or paste form is used as catalyst.

Abstract: Process for the preparation of a DMC catalyst useful in the polymerization of alkylene oxides into polyether polyols, which process comprises the steps of (a) combining an aqueous solution of a metal salt with an aqueous solution of a metal cyanide salt and reacting these solutions, wherein at least part of this reaction takes place in the presence of an organic complexing agent, thereby forming a dispersion of a solid DMC complex in an aqueous medium; (b) combining the dispersion obtained in step (a) with a liquid, which is essentially insoluble in water and which is capable of extracting the solid DMC complex formed in step (a) from the aqueous medium, and allowing a two-phase system to be formed consisting of a first aqueous layer and a layer containing the DMC complex and the liquid added; (c) removing the first aqueous layer; and (d) recovering the DMC catalyst from the layer containing the DMC catalyst.

Abstract: The present invention relates to a process for the preparation of polyether polyols by the reaction of alkylene oxides and compounds containing active hydrogens, in the presence of specific Lewis acid metal compounds as catalysts, novel bis(perfluoroalkylsulfonic acid) compounds of Group 13 of the Periodic Table of the Elements, and to a process for the preparation thereof and the use thereof as catalysts for ring-opening polymerization of cyclic ethers.

Abstract: The invention is directed to a process for preparing a polyether polyol by the polyaddition of an alkylene oxide on to a starter compound containing active hydrogen atoms under basic catalysis in the presence of phosphonium cations.

Abstract: The present invention provides a process for producing a (poly)alkylene glycol monoalkyl ether with high selectivity and high yield. In this process, the (poly)alkylene glycol monoalkyl ether is produced by reacting an olefin and a (poly)alkylene glycol in the presence of a catalyst, wherein: 1) a crystalline metallosilicate is used as the catalyst, and at least a portion of the used catalyst is regenerated, and the regenerated catalyst is recycled as the catalyst for the reaction; or 2) the reaction between the olefin and the (poly)alkylene glycol is carried out in the presence of either or both of a (poly)alkylene glycol dialkyl ether and an alcohol.

Abstract: Disclosed are a composition for preventing clogging of oil filters for various internal combustion engines, the composition comprising at least one hydroxyl-containing component selected from the group consisting of: compounds represented by the formula (1) R1O—(R2O)m—H  (1)  wherein R1 is hydrogen or C1 to C8 alkyl, R2 is C2 to C10 alkylene, m is an integer of 1 to 10, and when m is 2 or more, the two or more R2 groups may be the same or different; and compounds represented by the formula (2)  wherein R3 is C2 to C4 alkylene, R4 is hydrogen or C1 to C10 alkyl, n is an integer of 0 to 8, and when n is 2 or more, the two or more R3 groups may be the same or different; a method for preventing oil filter clogging using the composition, and an engine oil composition containing the composition.

Abstract: A single-stage method for producing &agr;-hydroxy ethers by oxidizing olefinic substrates with organic hydroperoxides and opening the resultant oxirane ring by means of monovalent or polyvalent alcohols wherein a molybdenum compound in combination with a compound selected from the group consisting of boron trifluoride, aluminum oxides, 1,8-diazabicyclo-[5.4.0]-undec-7-ene or 1,4-diazabicyclo-[2.2.2]-octane, and mixtures thereof is used as a catalyst system.

Abstract: An alkoxylation catalyst is prepared by a) reaction of one mol of a dicarboxylic acid with from 1.5 to 8 mol of an alkoxylated alcohol to form the corresponding dicarboxylic monoester, b) formation of an alkaline earth metal salt of the dicarboxylic monoester by addition of water and from 0.45 to 0.55 mol of a basic alkaline earth metal compound per mol of dicarboxylic acid originally used, c) partial neutralization of the alkaline earth metal salt by addition of from 0.25 to 0.7 mol of H2SO4 per mol of basic alkaline earth metal compound originally used and d) removal of the water present at a temperature of less than 100° C. The catalyst prepared in this way makes it possible to prepare colorless alkoxylates having a narrow homologue distribution.

Abstract: Double-metal cyanide catalysts of the formula M1a[M2(CN)b(A)c]d. fM1gXn. h (H2O).

Abstract: A process for polymerizing cyclic ethers over a heterogeneous catalyst comprises using a heterogeneous catalyst comprising one or more pillared interlayered clays (PILCs).

Abstract: The invention relates to a process for conducting a chemical reaction characterized by an equilibrium in a reaction system designed as a loop reactor, said loop reactor comprising a reactor vessel (1), at least one loop connected to said reactor vessel (1) each by means of an outlet and an inlet, said loop comprising means (3) for pumping over a fluid reaction material, at least one he exchanger (4), optionally means (5) for feeding said reaction material into Me reactor vessel (1) and a separate gas loop (8) which is connected to the gas space of the reactor vessel (1) above the reaction mixture and has separate means for feeding a gas into the gas loop (8), for withdrawing gas from the gas loop (8) and/or for treating said gas circulating in the gas loop (8), said process comprising the steps of circulating and/or treating said gas in said gas loop (8), feeding said gas into the reactor vessel (1) for influencing the equilibrium of a reaction conducted in said reactor vessel (1) and being characterized by t

Abstract: The present invention relates to a process for the preparation of polyether polyols by the reaction of alkylene oxides and compounds containing active hydrogens, in the presence of specific Lewis acid metal compounds as catalysts, novel bis(perfluoroalkylsulfonic acid) compounds of Group 13 of the Periodic Table of the Elements, and to a process for the preparation thereof and the use thereof as catalysts for ring-opening polymerization of cyclic ethers.

Abstract: A continuous process for the production of polyadducts of alkylene oxide on a chain initiator with at least one active hydrogen comprises the step of: (a) providing n reaction units constituted by a tubular reactor (11), and a heat exchanger (14) downstream of the tubular reaction (11); (b) supplying the preheated chain initiator and the alkylene oxide to the reactor of the first reaction unit; (c) reacting the chain initiator with the alkylene oxide to obtain a first mixture; (d) cooling the first mixture by means of the heat exchanger (14); (e) supplying the reactor of the following reaction unit with the cooled mixture and with alkylene oxide; (f) repeating the procedure until the last reaction unit and then discharging the last mixture containing the desired product. The tubular reactors are vertical and the chain initiator and alkylene oxide are sprayed into the top of the reactor where a gas liquid reaction occurs.

Abstract: This application relates to a process for making glycol ethers, said process comprising reacting an olefin oxide with an alcohol over a catalyst comprising a crystalline metallosilicate which is basic in character, wherein the molar ratio of alcohol to olefin oxide employed is at least 2:1.

Abstract: A process for preparing an organic compound, comprising conducting an organic reaction in the presence of a phosphine oxide represented by formula (1); ##STR1## where R.sup.1 is the same or different and each represents a hydrogen or hydrocarbon group with 1 to 10 carbon atoms, and x is the amount of water as a molar ratio which is 0 to 5.0, exhibiting a high catalytic performance especially in an organic reaction involving an alkylene oxide.

Abstract: A process for producing polyhydroxy ethers having the formula (I) (HO).sub.(w--M) W(OV).sub.m, in which W represents an organic group and OV a structural element containing hydroxyl groups, having the formula (III) ##STR1## A multifunctional alcohol W(OH).sub.w (II) is reacted with an .alpha.,.beta.-unsaturated carbonyl compound XCH.dbd.CY--CZ.dbd.O (IV) and formaldehyde in the presence of a base. The .alpha., .beta.-unsaturated carbonyl compound (IV) and the remaining quantities of formaldehyde, multifunctional alcohol (II) and base are added continuously or periodically to an aqueous solution or suspension containing at least 10 mole % of the multifunctional alcohol (II), at least 10 to 70 mole % of the formaldehyde and at least 10 mole % of the base. Preferred multifunctional alcohols (II) are pentaerythritol, TMP and TME. Preferred carbonyl compounds (IV) are acrolein and .alpha.-alkylacrolein. New asymmetric polyhydroxy ethers are also disclosed.

Abstract: The amount of high molecular weight impurity present in a polyether polyol produced by alkoxylation of an active hydrogen-containing initiator using an epoxide such as propylene oxide and a substantially amorphous highly active double metal cyanide complex catalyst may be advantageously lowered by having a non-protic Lewis acid present during the epoxide polymerization. The use of halides such as zinc chloride and aluminum chloride is especially effective for such purposes. In a preferred embodiment, minor amounts of water are also present during polymerization. The higher purity polyether polyols thereby produced are particularly useful in the preparation of slab and molded polyurethane foams, which tend to collapse or become excessively tight when elevated levels of high molecular tail are present in the polyether polyol.

Abstract: Stabilizer precursors and preformed stabilizers having induced unsaturation, and prepared from low intrinsic unsaturation-containing polyoxyalkylene polyether polyols may be used to form polymer polyols of higher solids content, lower viscosity, and superior filterability and particle size than polymer polyols prepared from stabilizers derived from polyols having higher intrinsic unsaturation, even when the latter are coupled to form high molecular weight stabilizers.

Abstract: A method and apparatus is provides for decontamination of soil from contaminates such as polychlorinated biphenyls. The method involves (a) admixing a short chain alcohol and a ethoxylated alcohol to provide a solvent composition, (b) admixing the solvent composition with the contaminated soil to extract the contaminant from the soil into the solvent to form contaminated solvent, (c) separating the soil from the contaminated solvent, (d) washing of the decontaminated soil with water to remove residual solvent from the soil, and (e) distillation of the contaminated solvent to separate the reusable short chain alcohol as a light fraction from a heavy fraction containing the ethoxylated alcohol and the contaminant.

Abstract: This Invention discloses the use of ascorbic and citric acid, their salts, ethers, acid esters and mixtures thereof in a method for the prevention of peroxide formation, and/or for decomposing peroxides already formed in polyethers. Hereby, the polyethers are made reactive to hydrosilylation by silanes and hydrosiloxanes. When the polyether treatment is done with mixtures of ascorbic acid and sodium ascorbate and allyl polyethers, the hydrosilylation product contains reduced levels of propanal. The copolymers prepared using the treated polyethers are efficient stabilizers of flexible polyurethane foams and rigid polyurethane and polyisocyanurate foams.

Abstract: An arrangement for a falling film type reactor uses corrugated plates to improve the distribution and dispersion of the gaseous reactant into the liquid. Corrugated plates introduce increased turbulence for promoting better distribution and dispersion of the gas. Corrugation angles can be varied to suit the fluid flow properties of the liquid reactant. The reactor arrangement can also include heat transfer channels defined by the corrugated plates in an alternate arrangement of heat transfer channels and gas liquid contacting channels. The corrugations may also be varied to suit the particular heat transfer requirements of the reactions. The corrugated plates are spaced apart in the contacting channels to prevent localized film contact and placed in contact in the heat exchange portion to stabilize the plate elements defining the corrugations.

Abstract: Double metal cyanide-catalyzed polyols are made by an improved process in which a starter is continuously added during polymerization of the epoxide. The process includes a continuously added starter (S.sub.c), and optionally, an initially charged starter (S.sub.i). The continuously added starter comprises at least about 2 equivalent percent of the total starter used. The process enables the use of water and low molecular weight polyol starters in DMC-catalyzed polyol synthesis. In addition, the process gives polyether polyols having reduced levels of high molecular weight polyol tail, which can adversely affect polyurethane foam processing.

Abstract: Polyol ether derivatives, a method for producing the polyol ether derivatives, and a working fluid composition for a refrigerating machine containing a hydrofluorocarbon and a refrigeration oil containing the polyol ether derivatives as a base oil.

Abstract: Active hydrogen containing organic compounds, for example alcohols, thiols, phenols, thiophenols, carboxylic acids, amides and amines, are alkoxylated, for example, ethoxylated, using catalysts comprising a salt of a Group IIa or Group Ia element and an oxyacid of at least one element chosen from Group IVb, Group Vb or Group VIb, for example, lanthanum titanate, barium titanium, barium strontium titanate, yttrium titanate, lanthanum zirconate, barium zirconate, lanthanum hafnate, barium strontium titanate zirconate and neodymium titanate. The catalyst provide narrow distribution of alkoxylation species and efficient reaction rates.

Abstract: An amount of water is added to a glycol solution to be purified to enable segregation of the resulting mixture into a hydrocarbon phase and a glycol phase. The hydrocarbon phase is separated from the glycol phase and said glycol phase is desalted, e.g. by electrodialysis, to give a desalted and substantially hydrocarbon-free glycol solution which is then concentrated by steam stripping. The method is useful for purifying waste glycol solutions resulting from oil or gas production effluent processing using glycols, and in particular from a gas hydrate inhibition treatment or natural gas dehydration.

Abstract: The purification process comprises removing carboxylic acids and/or carboxylic acid salts contained as impurities in a fluorinated polyether having at at least one end thereof a terminal vinyl group linked thereto through an amide group-containing linkage by heating, in the presence of an amine compound such as triethylamine and dimethylaminotrimethylsilane, the fluorinated polyether containing said impurities or a reaction mixture obtained after the completion of reaction in a process of producing said fluorinated polyether. According to the purification process, the impurities can be easily removed from said fluorinated polyether. When the thus purified fluorinated polyether is used as a starting material for an addition type curable composition together with a SiH group-containing organosilicon compound, a liquid rubber material excellent in curability and storage stability can be obtained.

Abstract: The present invention is directed to a process for the preparation of polyoxyalkylene ether surfactant compositions comprising the steps of combining an admixture of alkoxylated alcohols with an acid catalyst and 1-6 molar equivalents of an aldehyde. The mixture is reacted at between about 50.degree. C. and about 180.degree. C. and at between about 1 atm and 10 atm pressure in the absence of a distillation step to produce the polyoxyalkylene ether surfactant composition.

Abstract: Double metal cyanide-catalyzed polyols are made by an improved process in which a starter is continuously added during polymerization of the epoxide. The process includes a continuously added starter (S.sub.c), and optionally, an initially charged starter (S.sub.i). The continuously added starter comprises at least about 2 equivalent percent of the total starter used. The process enables the use of water and low molecular weight polyol starters in DMC-catalyzed polyol synthesis. In addition, the process gives polyether polyols having reduced levels of high molecular weight polyol tail, which can adversely affect polyurethane foam processing.

Abstract: A process reaction between: (1) a compound that contains one or more epoxide moieties per molecule, and (2) a compound that contains one or more primary aliphatic hydroxyl groups per molecule; is catalyzed by: (3) a catalyst compound containing one or more trifluoromethanesulfonate moieties and one or more silyl moieties and run at a temperature of no more than 130.degree. C., such that the catalyst preferably catalyzes reaction at the primary aliphatic hydroxyl group, so that the resulting resin does not gel.

Abstract: Process for carrying out gas/liquid reactions at from (-50.degree.) to 300.degree. C. and from 0.1 to 100 bar by carrying out the reaction in the absence of a continuous gas phase, and, as a special case, a process for the batchwise reaction of acetylene in the liquid phase at from 0.degree. to 300.degree. C. and from 2 to 30 bar, in which acetylene is introduced a) in the absence of a continuous gas phase and b) under isobaric conditions to a degree of saturation of from 5 to 100%.

Abstract: Monoalkyl glycol ether is separated from dialkyl glycol ether by phase separation using a hydrocarbon solvent, preferably with the addition also of water.

Abstract: Low-odor, higher molecular weight polyether polyols are produced by purifying the polyether polyols at temperatures of 110.degree. to 150.degree. C. and pressures of 10 to 70 hPa with the addition of 5 to 30% by weight of water, wherein the water is passed in finely divided form, with a droplet diameter of about 5 to 100 .mu., through the polyether polyols to be purified for a time of metered addition of 1 to 5 hours.

Abstract: According to the invention, the alkoxylation of compounds containing active hydrogen atoms is carried out in the presence of specific alkaline earth metal salts of alkylor alkenylsuccinic monoesters as catalyst. The alkoxylates obtained have a narrow homolog distribution and a good appearance.

Abstract: A method of production of an ether compound from an acetal compound or a ketal compound which is excellent in conversion and selectivity and does not cause corrosion of apparatuses and a novel useful polyvinyl ether compound as lubricating oil for compression-type refrigerators, electric insulation oil and the like are disclosed. The method of production of the present invention comprises reaction of an acetal compound or a ketal compound with hydrogen in the presence of a solid catalyst having acidic property and hydrogenation ability to produce the corresponding ether compound. The polyvinyl ether compound of the present invention comprises the constituting unit expressed by the general formula: ##STR1## (characters in the general formula are the same as those described in the specification), contains none of unsaturated bond, acetal structure and aldehyde structure in the molecule and has weight average molecular weight in the range of 300 to 3000.

Abstract: A method of production of an ether compound from an acetal compound or a ketal compound which is excellent in conversion and selectivity and does not cause corrosion of apparatuses and a novel useful polyvinyl ether compound as lubricating oil for compression-type refrigerators, electric insulation oil and the like are disclosed. The method of production of the present invention comprises reaction of an acetal compound or a ketal compound with hydrogen in the presence of a solid catalyst having acidic property and hydrogenation ability to produce the corresponding ether compound.

Abstract: A method for the production of polytetramethylene ether glycol wherein polymerization of tetrahydrofuran in the presence of fluorosulfonic acid is followed by hydrolysis of the resulting polymer, characterized by(1) using the fluorosulfonic acid at 0.007-0.3 molar equivalents with respect to the tetrahydrofuran;(2) using in combination therewith fuming sulfuric acid which contains free sulfur trioxide at 0.05-1.0 molar equivalent with respect to the fluorosulfonic acid; and(3) adding said fuming sulfuric acid to the tetrahydrofuran prior to adding the fluorosulfonic acid thereto.According to the method, high quality polytetramethylene ether glycol with a low fluorine content may be obtained at a high yield without lowering the polymerization temperature. For example, PTMG may be obtained with 3 or fewer, and preferably 2 or fewer terminal fluorines per 2,000 termini of the resulting PTMG.

Abstract: Oligoglycerol mixtures having a high diglycerol content are prepared by a process in which glycerol is condensed in the presence of zeolites corresponding to formula (I)M.sub.2/z O * Al.sub.2 O.sub.3 * x SIO.sub.2 * y H.sub.2 O (I)in which M is an alkali metal or alkaline earth metal having a valency of z, x is a number of 1.8 to 12 and y is a number of 0 to 8. The water of condensation which is formed during the reaction, is continuously removed from the reaction mixture and the reaction is terminated when the quantity of water theoretically necessary for the formation of diglycerol has been separated.

Abstract: A process for the preparation of adducts by reacting an alcohol with an epoxy compound in the presence of a catalyst, which comprises reacting an alcohol of formula I ##STR1## wherein A is an aliphatic, cycloaliphatic or araliphatic radical and r is a number from 1 to 10, with a mono- or diepoxide in the equivalent ratio of 1:20 to 20:1, based on the hydroxyl and epoxy groups, in the presence of a metal complex of formula II as catalyst[M.sup.n+ (L.sub.1).sub.x (L.sub.2).sub.y (L.sub.3.sup.m-).sub.z ][X.sup.k- ].sub.(n-zm)/k (II),whereinM is a metal of the main groups or subgroups of the Periodic Table of the Elements,L.sub.1 and L.sub.2 are weakly bonded, neutral, unidentale or multidentate ligands,L.sub.3 is a strongly bonded, non-replaceable neutral or anionic unidentale or multidentate ligand,X is an anion of the following formulae BF.sub.4.sup.-, PF.sub.6.sup.-, AsF.sub.6.sup.-, SbF.sub.6.sup.-, ClO.sub.4.sup.-, IO.sub.4.sup.-, NO.sub.3.sup.

Abstract: A process for purifying propylene oxide containing an unacceptable quantity of a poly(propylene oxide) polymer contaminant having a molecular weight of at least about 50,000, comprising the step of filtering propylene oxide containing such polymer contaminant through one or more membranes to provide a propylene oxide product fraction having an acceptable quantity of poly(propylene oxide) polymer contaminant therein and a second fraction which is more highly concentrated in such polymer contaminant.