A method for purifying a specific trityl group-containing monodispersed polyethylene glycol from a mixture containing the trityl group-containing monodispersed polyethylene glycol and a specific ditritylated impurity. The method includes performing steps (A), (B) and (C). Step (A): a step of esterifying the hydroxyl group of the trityl group-containing monodispersed polyethylene glycol by a specific method; Step (B): a step of extracting the esterified compound by a specific method; and Step (C): a step of hydrolyzing the esterified compound to obtain the trityl group-containing monodispersed polyethylene glycol.

A method for purifying a specific trityl group-containing monodispersed polyethylene glycol from a mixture containing the trityl group-containing monodispersed polyethylene glycol and a specific ditritylated impurity. The method includes performing steps (A), (B) and (C). Step (A): a step of esterifying the hydroxyl group of the trityl group-containing monodispersed polyethylene glycol by a specific method; Step (B): a step of extracting the esterified compound by a specific method; and Step (C): a step of hydrolyzing the esterified compound to obtain the trityl group-containing monodispersed polyethylene glycol.

A polyalkylene glycol derivative with a minimal impurity content is prepared simply by the steps of reacting a compound having formula (III-I) or (III-II) with an electrophile having formula (IV) in the presence of an optional basic compound, to form a reaction solution containing a compound having formula (V), and passing the reaction solution through a column of cation and anion exchange resins to remove water-soluble impurities, for thereby purifying the desired polyalkylene glycol derivative.
R.sup.1R.sup.2OR.sup.3O.sub.n-1R.sup.3O.sup.M.sup.+(III-I)
R.sup.1R.sup.2OR.sup.3O.sub.n-1R.sup.3OH(III-II)
R.sup.4R.sup.5X(IV)
R.sup.1R.sup.2OR.sup.3O.sub.nR.sup.5R.sup.4(V)

A polyalkylene glycol derivative with a minimal impurity content is prepared simply by the steps of reacting a compound having formula (III-I) or (III-II) with an electrophile having formula (IV) in the presence of an optional basic compound, to form a reaction solution containing a compound having formula (V), and passing the reaction solution through a column of cation and anion exchange resins to remove water-soluble impurities, for thereby purifying the desired polyalkylene glycol derivative.
R.sup.1R.sup.2OR.sup.3O.sub.n-1R.sup.3O.sup.M.sup.+(III-I)
R.sup.1R.sup.2OR.sup.3O.sub.n-1R.sup.3OH(III-II)
R.sup.4R.sup.5X(IV)
R.sup.1R.sup.2OR.sup.3O.sub.nR.sup.5R.sup.4(V)

The present invention relates to a method for selectively separating propylene carbonate by adding water to reaction products comprising a polyether carbonate polyol and propylene carbonate, which are generated from a polymerization reaction of propylene oxide and carbon dioxide under a double metal cyanide (DMC) catalyst, wherein an economical and effective separation of propylene carbonate can be achieved.

A method of purifying a crude polyalkylene oxide polymer that contains a catalyst, such as potassium hydroxide. The method comprises contacting the crude polyalkylene oxide polymer with a composition comprising an acid functionalized silicate, such as an acid functionalized magnesium silicate adsorbent containing at least one acid in an amount effective to remove the catalyst from the polyalkylene oxide polymer. Such a method provides for an improved removal of the catalyst from the polyalkylene oxide polymer.

A method of purifying a crude polyalkylene oxide polymer that contains a catalyst, such as potassium hydroxide. The method comprises contacting the crude polyalkylene oxide polymer with a composition comprising an acid functionalized silicate, such as an acid functionalized magnesium silicate adsorbent containing at least one acid in an amount effective to remove the catalyst from the polyalkylene oxide polymer. Such a method provides for an improved removal of the catalyst from the polyalkylene oxide polymer.

The present invention provides a high-molecular-weight polyether polyol ensuring that when used as a polyurethane raw material, a polyurethane having excellent flexibility and elastic recovery can be obtained; and a method for producing, with high productivity, a polyether polyol having a higher number average molecular weight and a narrower molecular weight distribution than those of the raw material polyether polyol, and the polyether polyol of the present invention has a number average molecular weight of 3,500 to 5,500 and a molecular weight distribution of 1.7 to 3.0.

The present invention provides a high-molecular-weight polyether polyol ensuring that when used as a polyurethane raw material, a polyurethane having excellent flexibility and elastic recovery can be obtained; and a method for producing, with high productivity, a polyether polyol having a higher number average molecular weight and a narrower molecular weight distribution than those of the raw material polyether polyol, and the polyether polyol of the present invention has a number average molecular weight of 3,500 to 5,500 and a molecular weight distribution of 1.7 to 3.0.

A purification method of a polyethylene glycol compound having one carboxyl group. In the method, an aqueous solution of the compound having a pH of 8 to 11 is prepared, the aqueous solution and a mixed organic solvent are mixed at a temperature of 15 C. or more and 50 C. or less and the mixture is separated into an organic layer and an aqueous layer. In the mixed organic solvent, a ratio of solvent I is from 25 to 60% by mass, and a ratio of solvent II is from 75 to 40% by mass. Solvent I is a hydrocarbon, solvent II is a halogenated hydrocarbon, a mixing ratio Y (organic solvent I/organic solvent II), a temperature T ( C.) at mixing and a weight average molecular weight M of the compound satisfy a relationship of 3.1110.sup.6M+0.084Y0.0135T1.7710.sup.6M+0.404.