Abstract: Different methods for the preparation of high purity NaAlCl4 are disclosed. The methods includes charging a feed having an intimate mixture of aluminum chloride, sodium chloride, and aluminum metal, to a reactor at an initial temperature less than about 80° C., carrying out a solid state reaction to form a solid NaAlCl4 at an intermediate temperature less than about 145° C., melting the formed solid NaAlCl4 at an elevated temperature greater than about 150° C. to produce molten phase NaAlCl4, holding the reactor at a raised temperature greater than about 165° C. to substantially complete formation of colorless NaAlCl4 and filtering the reactor contents at a final temperature greater than about 165° C.

Abstract: Different methods for the preparation of high purity NaAlCl4 are disclosed. The methods includes charging a feed having an intimate mixture of aluminum chloride, sodium chloride, and aluminum metal, to a reactor at an initial temperature less than about 80° C., carrying out a solid state reaction to form a solid NaAlCl4 at an intermediate temperature less than about 145° C., melting the formed solid NaAlCl4 at an elevated temperature greater than about 150° C. to produce molten phase NaAlCl4, holding the reactor at a raised temperature greater than about 165° C. to substantially complete formation of colorless NaAlCl4 and filtering the reactor contents at a final temperature greater than about 165° C.

Abstract: The invention provides improved hollow fiber membranes having at least two layers, and methods for forming the same. The methods include co-extruding a first composition, a second composition, and a third composition to form a dual layer hollow fiber membrane. The first composition includes a glassy polymer; the second composition includes a polysiloxane; and the third composition includes a bore fluid. The dual layer hollow fiber membranes include a first layer and a second layer, the first layer being a porous layer which includes the glassy polymer of the first composition, and the second layer being a polysiloxane layer which includes the polysiloxane of the second composition.

Abstract: A method for synthesis of N-methyl piperazine diphenolamide is presented. The method includes contacting diphenolic acid with N-methyl piperazine to form a reaction mixture; and heating the reaction mixture to form a reaction product including N-methyl piperazine diphenolamide. An associated composition is also presented.

Abstract: A membrane including a polyarylnitrile copolymer is presented. The polyarylnitrile copolymer includes structural units having a formula (I) and at least one terminal group having a formula (II): wherein “a” is 0, 1, 2, or 3; “m” is an integer having a value of 35 to 150; R1 is independently at each occurrence a hyrogen atom, a halogen atom, a nitro group, a cyano group, a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical; R2 and R3 are independently a C1-C12 aliphatic radical, a C3-C12 cycloaliphatic radical, or a C3-C12 aromatic radical; L is an oxygen atom or a sulfur atom; and Ar is independently at each occurrence a residue of an aromatic diol or a residue of an aromatic dihalide.

Abstract: The invention provides improved hollow fiber membranes having at least two layers, and methods for forming the same. The methods include co-extruding a first composition, a second composition, and a third composition to form a dual layer hollow fiber membrane. The first composition includes a glassy polymer; the second composition includes a polysiloxane; and the third composition includes a bore fluid. The dual layer hollow fiber membranes include a first layer and a second layer, the first layer being a porous layer which includes the glassy polymer of the first composition, and the second layer being a polysiloxane layer which includes the polysiloxane of the second composition.

Abstract: A process for preparing polyimide resins comprises stirring a diamine and a dianhydride in a solvent to form a slurry; heating the slurry to a temperature sufficient for the diamine and dianhydride to react wherein the temperature is below the melting point of the dianhydride, below the melting point of the diamine, or below the melting points of the dianhydride and diamine; and reacting the diamine and dianhydride to form a polyimide having sufficient molecular weight to precipitate from the solvent.

Abstract: Disclosed herein is a method comprising: (a) adding an aqueous solution comprising a quaternary ammonium salt to an organic solvent in a vessel under an inert atmosphere, thereby forming a first mixture comprising the quaternary ammonium salt and the solvent; and (b) mixing the first mixture at a temperature and for a time sufficient to remove water and a portion of the solvent from the first mixture, wherein the mixing is performed in an inert atmosphere and the temperature is less than the decomposition temperature of the quaternary ammonium salt.

Abstract: Disclosed herein is a method comprising: (a) adding an aqueous solution comprising a quaternary ammonium salt to an organic solvent in a vessel under an inert atmosphere, thereby forming a first mixture comprising the quaternary ammonium salt and the solvent; and (b) mixing the first mixture at a temperature and for a time sufficient to remove water and a portion of the solvent from the first mixture, wherein the mixing is performed in an inert atmosphere and the temperature is less than the decomposition temperature of the quaternary ammonium salt.

Abstract: A method for preparing a polyimide includes introducing a mixture of an oligomer and a solvent to an extruder, removing solvent via at least one extruder vent, and melt kneading the oligomer to form a polyimide. The polyimide has a low residual solvent content. The method is faster than solution polymerization of polyimides, and it avoids the stoichiometric inaccuracies associated with reactive extrusion processes that use monomers as starting materials.

Abstract: Methods of reducing the amount of undesirable by-products in the production of polymers are disclosed. The resulting polyetherimides have lower polydispersivity and enhanced thermomechanical properties. In some embodiments, cyclic and low molecular weight linear oligomers are also obtained.

Abstract: Aromatic polyethers are prepared by displacement polymerization reaction in the presence of a water-immiscible solvent with boiling point at atmospheric pressure of greater than 110° C. and a density ratio to water of greater than 1.1:1 at 20-25° C. The polyethers are purified by processes comprising aqueous extraction, or filtration, or a combination thereof.

Abstract: Aromatic polyethers are prepared by displacement polymerization reaction in the presence of a water-immiscible solvent with boiling point at atmospheric pressure of greater than 110° C. and a density ratio to water of greater than 1.1:1 at 20-25° C. The polyethers are purified by processes comprising aqueous extraction, or filtration, or a combination thereof.

Abstract: High purity sterically hindered diaryl chlorophosphates, having a purity of at least 98% by weight and a proportion of the corresponding aryl dichlorophosphate less than 1.5% by weight, are prepared by a method including the steps of gradually introducing POCl3 into a mixture of a sterically hindered hydroxyaromatic compound such as 2,6-xylenol and a catalyst such as magnesium chloride, and gradually increasing the temperature of the reaction mixture to a final level in the range of about 135-150° C. The products are capable of reaction with amines such as piperazine to produce sterically hindered phosphoramidates.

Abstract: Sterically hindered phosphoramidates such as N,N′-bis[di-(2,6-xylyl)phosphoryl]piperazine are prepared by the reaction of a sterically hindered diaryl chlorophosphate, such as di-(2,6-xylyl) chlorophosphate, with a basic nitrogen compound containing at least two basic N—H groups, preferably a heterocyclic compound such as piperazine, in the presence of an acid acceptor such as triethylamine. The reaction is conducted in methylene chloride or an aromatic hydrocarbon such as toluene as solvent. If an aromatic hydrocarbon is employed, there is also present at least one dipolar aprotic nitrogen compound, such as 4-dimethylaminopyridine, in an amount effective to increase the reaction rate.

Abstract: Polyether polymers such as polyetherimides are prepared by a two-step reaction. The first step is the reaction between an alkali metal salt of a dihydroxy-substituted aromatic hydrocarbon, such as bisphenol A disodium salt, and a substituted aromatic compound such as 1,3-bis[N-(4-chlorophthalimido)]benzene, the alkali metal salt being employed in an amount less than stoichiometric. The intermediate low molecular weight polymer thus produced then undergoes reaction with additional alkali metal salt. By this method, a polyether polymer of closely controlled molecular weight can be conveniently prepared.

Abstract: Bis(halophthalimides) such as, 3-bis[N-(4-chlorophthalimido)]benzene are prepared in slurry in an organic liquid such as o-dichlorobenzene or anisole, by a reaction at a temperature of at least 150° C. between at least one diamino compound, preferably an aromatic diamine such as m- or p-phenylenediamine, and at least one halophthalic anhydride such as 4-chlorophthalic anhydride, in the presence of an imidization catalyst such as sodium phenylphosphinate. The solids content of the reaction mixture is at least about 5% and preferably at least about 12% by weight. The product slurry may be employed directly in the preparation of polyetherimides, and similar slurries may be employed to prepare other polyether polymers.