Abstract: Monoisocyanate impurities are removed from a process stream obtained when solvent is separated from a polyisocyanate product. The monoisocyanates are reacted with amine compounds at specific molar ratios to produce ureas. The ureas can be discarded by burning, landfilling or otherwise. Alternatively the ureas can be recycled back into the polyisocyanate manufacturing process, where they are formed into biuret compounds that can remain with the polyisocyanate product.

Abstract: Antioxidants used for overcoat layers and processes for making the same. The present process for making the antioxidant has proven to be repeatable, cheaper, faster and safer than conventional processes. In particular, the present process uses a different solvent system where crude bis(4-diethylamino-2-methylphenyl)-(4-diethylaminophenylmethane) is dissolved in methylethyl ketone at room temperature, followed by product precipitation in a warm mixture of ethanol and water.

Abstract: The present disclosure relates to compositions, systems, and methods of forming an amine (e.g., methylenedianiline (MDA)) using an acid catalyst including, for example, a metal oxide-silica catalyst calcined at temperature(s) of about ?500° C. to form a solid acid silica-metal oxide catalyst. A metal oxide of a solid acid silica-metal oxide catalyst may comprise alumina. A process for making a solid acid silica-metal oxide catalyst may comprise calcining an amorphous alumina-silica material at temperature(s) of about ?500° C. and/or under an anhydrous and/or inert atmosphere. A rearrangement reaction of the condensation product of aniline and formaldehyde in the presence of a solid acid silica-metal oxide catalyst may yield more MDA and/or more desirable isomer(s) of MDA than reactions performed with a corresponding catalyst calcined at temperature(s) of less than 500° C.

Abstract: The invention relates to a process for preparing mixtures of diphenylmethanediamine and polyphenylenepolymethylenepolyamines, which comprises the steps a) reaction of aniline with formaldehyde in the presence of hydrochloric acid, b) neutralization of the reaction mixture formed in step a) c) separation of the organic phase from the aqueous phase, d) work-up of the organic phase, e) work-up of the aqueous phase, wherein step e) comprises at least the steps e1) extraction of the aqueous phase with an organic solvent, e2) stripping of the aqueous phase obtained in step e1), e3) absorption of the solution obtained from step e2).

Abstract: The present invention provides a method of preparing polymethylene-polyphenyl-polyamine (briefly referred to as polyamine, DAM), in which a high gravity rotating bed is used as the mixing reactor of formaldehyde and aniline hydrochloride, the mixing solution of aniline hydrochloride and circulation solution and the formaldehyde are fed into the high gravity rotating bed reactor proportionally to carry out mixing and condensation reaction under a condition of a very high gravity; the materials leaving the high gravity rotating bed reactor is introduced into a stirred vessel to proceed with the pre-condensation reaction and obtain a condensation solution; and the process steps of heating, molecular rearrangement, neutralization, water washing and purification, etc. are completed to obtain the refined DAM.

Abstract: The invention provides an improved process for preparing diamines and polyamines from the diphenylmethane series by reacting aniline and formaldehyde in the presence of an acid catalyst, the improvement involving the aniline containing less than about 3 wt. % of diamines and polyamines from the diphenylmethane series, based on the weight of the aniline.

Abstract: A process for preparing methylenedianiline by reacting aniline with formaldehyde in the presence of acid catalysts comprising, in a semicontinuous process, introducing aniline with or without acid catalyst, feeding formaldehyde with or without acid catalyst through a mixing element into a circuit in which aniline with or without acid catalyst and with or without previously added formaldehyde is circulated and, after feeding in at least 50% of the total amount of formaldehyde to be fed in, heating the reaction mixture to a temperature above 75° C. In addition, the invention relates to a process for preparing polyisocyanates by phosgenation of amines obtainable in this manner and to the polyisocyanates obtainable by this process.

Abstract: Process for the production of methylenedianiline and its higher homologous products which comprises reacting aniline, or one of its derivatives, and formaldehyde, or one of its precursors, in one or two reactors in the presence of a solid acid catalyst selected from a zeolite or a silico-alumina, distilling off the reaction water or the water added with the reagents.

Abstract: A method for the preparation of aryl methyl ketones converts a variety of ethyl arenas to the corresponding aryl methyl ketones using a dioxygen-containing gas as the oxidant. The catalyst used for the reaction is a metal complex bearing general formulas as disclosed.

Abstract: Disclosed herein is a process for preparing a reaction product containing methylene diphenylamine, comprising reacting aniline and formaldehyde in the presence of an acid catalyst wherein the acid level of the resulting reaction mixture is reduced during digestion of the reaction mixture.

Abstract: Polyisocyanates of the diphenyl methane series having reduced color values are obtained by a) reacting aniline and formaldehyde in the presence of an acid catalyst to form a polyamine, b) neutralizing the reaction mixture containing polyamine with a base, c) separating the neutralized mixture into the aqueous and the organic phases, d) adding a base to the organic phase and then e) phosgenating the resulting polyamine to produce the corresponding polyisocyanate.

Abstract: A method of reacting a solution comprising a mixture of chemical compounds which are in chemical equilibrium with one another with at least one further chemical compound (9) is provided. The method comprises the following steps: fractionation of the solution by means of a separation method to give at least two fractions (5, 6) which are enriched in different chemical compounds of the mixture; and reaction of a fraction (5) with the further chemical compound or compounds (9). The fractionation is advantageously carried out using a film evaporator (1). Unreacted fractions (6) can be recirculated via a residence time vessel (3) back to the fractionation step. The method is particularly suitable for reactions of an aqueous formaldehyde solution in which various components of the solution (formaldehyde, methylene glycol, polyoxymethylene glycols) react in different ways.

Abstract: A process for preparing methylenedianiline by reacting aniline with formaldehyde in the presence of acid catalysts comprising, in a semicontinuous process, introducing aniline with or without acid catalyst, feeding formaldehyde with or without acid catalyst through a mixing element into a circuit in which aniline with or without acid catalyst and with or without previously added formaldehyde is circulated and, after feeding in at least 50% of the total amount of formaldehyde to be fed in, heating the reaction mixture to a temperature above 75° C. In addition, the invention relates to a process for preparing polyisocyanates by phosgenation of amines obtainable in this manner and to the polyisocyanates obtainable by this process.

Abstract: A process for the production of polymethylene polyphenyl polyisocyanates is disclosed. The process comprises phosgenating the corresponding polyamines in solution in an inert organic solvent, removing excess phosgene, and stripping the solvent, the improvement wherein at least 0.00015 percent by weight of hydrazine or hydrazine derivative per 100 percent by weight of polyamine are added to the polyamines at any time prior to the stripping step.

Abstract: Disclosed herein is an improved process for preparing a polyamine mixture derived by reacting aniline with formaldehyde in the presence of an acid catalyst the improvement comprising mildly reducing the polyamine mixture by a process step comprising catalytically or chemically hydrogenating the polyamine mixture in the presence of a metal catalyst.

Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and to the use thereof.

Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and their use.

Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and the use thereof.

Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and to their use.

Abstract: The invention relates to a process for the fractionation and purification of mixtures of aromatic polyamines and to the use thereof.

Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and the use thereof.

Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and the use thereof.

Abstract: The invention relates to a process for the fractionation and purification of aromatic polyamine mixtures and to the use thereof.

Abstract: The present invention encompasses an improved process for preparing polymethylene polyphenyl polyisocyanate comprising reacting phosgene with polymethylene polyphenyl polyamine, the improvement wherein the polymethylene polyphenyl polyamine is acidified prior to phosgenation.

Abstract: The invention relates to an improved process for the production of polynuclear aromatic polyamines by condensation of aniline with formaldehyde in the presence of water and acidic catalysts and working up of the reaction mixture by extraction with a hydrophobic solvent, the acid catalyst accumulating in the aqueous phase of the extraction step being reused.

Abstract: A method of purifying 4,4'-diaminodiphenylmethane comprising partially melting a crystal of crude 4,4'-diaminodiphenylmethane and removing a melt to obtain a high purity 4,4'-diaminodiphenylmethane. By utilizing the method, a high purity 4,4'-diaminodiphenylmethane is obtained efficiently with a low level of energy consumption.

Abstract: Disclosed herein is a process for preparing a reaction product containing methylene diphenylamine comprising reacting aniline with an aldehyde, in the presence of a low level of an acid wherein the acid level is reduced before digesting reaction mixture at a high temperature which is sufficient to effect a rearrangement of the intermediates to produce a reaction product containing methylene diphenylamines and low levels of impurities.

Abstract: Waste or scrap polyurethane may be conveniently and economically converted to useful active-hydrogen containing polyethers and polyamines by contacting the polyurethane with water, strong base, and an activating agent such as a quaternary ammonium compound containing at least 15 carbon atoms or an organic sulfonate containing at least 7 carbon atoms. The activating agent helps to accelerate the rate of base catalyzed hydrolysis.

Abstract: The invention relates to an improved process for the production of polynuclear aromatic polyamines by condensation of aniline with formaldehyde in the presence of water and acidic catalysts and working up of the reaction mixture by extraction with a hydrophobic solvent, the acid catalyst accumulating in the aqueous phase of the extraction step being reused.

Abstract: The invention relates to an improved process for producing alkenylated aromatic amines which involves the catalytic reaction of an aromatic amine with a diene. The improvement resides in using a solvent in which the aromatic amine and diene are soluble in the proportions present in the reaction but inert to the reaction.

Abstract: Bis-(amino-nitrophenyl)-methane can be produced in one stage with an approximately quantitative yield by condensing o-nitraniline and formaldehyde in water at a temperature of between 20.degree. and 40.degree. C. in the presence of sulfuric acid, and subsequently rearranging the formed methylene-bis-(o-nitraniline) by treatment of the reaction mixture at a temperature of between 90.degree. and 100.degree. C.

Abstract: This invention relates to an improved process for the preparation of polynuclear aromatic polyamines in which the reaction product is prepared by condensing aniline with formaldehyde in the presence of water and acidic catalysts and is worked up by extraction with a hydrophobic solvent. The acid catalyst that accumulates in the aqueous phase during the extraction process is reused.

Abstract: The present invention relates to an improved process for the preparation of multinuclear aromatic polyamines by the condensation of aniline with formaldehyde in the presence of water and acid catalysts and working up of the reaction mixture by extraction with a hydrophobic solvent. The acid catalyst obtained in the aqueous phase of extraction is reused.

Abstract: An arylamine such as aniline is condensed with formaldehyde in the presence of aqueous hydrochloric acid to form a mass containing the hydrogen chloride salt of a polyarylpolyamine. The mass is contacted with additional aniline thereby forming an organic phase and an aqueous phase, the 4,4'-polyarylpolyamine overwhelmingly being liberated from its salt form in the aqueous phase and being transferred to the organic phase. High recoveries of the 4,4'-diamino polycondensate are achieved.

Abstract: Liquid distillation residue formed in the phosgenation of polyamines to form polyisocyanates are hydrolyzed to reform the polyamine. The process comprises forming an adduct of the distillation residue with additional polyamine and then hydrolyzing the resulting adduct to convert the adduct to said polyamine.

Abstract: A process for purifying crude polyether polyols which are prepared by anionic polymerization of alkylene oxides in the presence of basic catalysts. The polyols are mixed with water and ortho-phosphoric acid in certain quantity ratios, an adsorption agent is incorporated in the reaction mixture, the mixture is filtered and the water is removed from the polyether polyol by distillation.

Abstract: Through condensation ortho- and para-isomers of methylene dianiline (MDA) as well as PMPPA are produced as condensation products from arylamines, especially from aniline, and formaldehyde in the presence of acid catalysts, in which at least one component is a perfluoro-carbonic acid. From this mixture of the condensation products, 4,4'-MDA (p-isomer) of high purity is obtained by crystallization while the homogeneous aqueous solution obtained is being cooled down. It has been discovered that the 4,4'-MDA salts of the perfluoro-carbonic acids are less soluble in water than the corresponding salts of the o-isomers and the PMPPA.

Abstract: An improvement is described in the process of preparing polymethylene polyphenyl polyamines by condensing aniline and formaldehyde in the presence of an acid catalyst in the initial condensation. The improvement enables the amount of acid which has to be neutralized at the end of the reaction to be substantially reduced or eliminated entirely. This is accomplished without sacrifice of the high level of 4,4'-isomer of di(aminophenyl)methane normally present in the diamine content of the polyamines when a mineral acid catalyst is employed in the condensation.

Abstract: Porous polyurethane solids such as open cell polyurethane foams are rapidly heated and hydrolytically decomposed into separate polyol component and diamine component by contacting the porous solids with saturated steam in a heated vacuum chamber. Separation of high quality liquid polyol and diamine is achieved.

Abstract: Preparing a dispersion of methylenedianiline/inorganic salt complex curing agent of small particle size which comprises: (a) agitating while reacting 3 moles of 4,4'-methylenedianiline with not less than 1 mole of a salt selected from the group consisting of sodium chloride, sodium bromide, sodium iodide, lithium chloride, lithium bromide and lithium iodide in the presence of water and a benzenoid hydrocarbon solvent for the methylenedianiline; (b) separating the resulting complex having an average particle size diameter of less than about 10 .mu.m from the bulk of the hydrocarbon solvent; (c) drying said complex; and (d) dispersing said complex in a substantially nonvolatile liquid carrier that is inert to the complex; with the proviso that steps (c) and (d) can be carried out in any order or substantially simultaneously.