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 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 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 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 present invention relates to a process for the preparation of a polyisocyanate comprising(a) thermally decomposing in a tube reactor a solution of an N-substituted carbamic acid ester corresponding to said polyisocyanate in a solvent used as decompositoin medium, wherein said solvent (i) is capable of dissolving the carbamic acid ester, (ii) is stable at the decomposition temperature and chemically inert towards the carbamic acid esters and the polyisocyanate product, (iii) can be distilled without decomposing under the conditions of decomposition of carbamic acid estes, and (iv) has at least one miscibility gap with an extracting agent used according to the extraction step (c), said solutions being carried along the internal wall of reactor;(b) separating the gaseous materials formed in the tube reactor by fractional condensation into a fraction I comprised mainly of the alcohol by-product and a fraction II comprised mainly of polyisocyanates, isocyanatourethanes, unreacted carbamic acid ester, and the s

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: Diisocyanates and isomer mixtures of diisocyanates corresponding to the formula ##STR1## in which R.sup.1, R.sup.2, m and n are as defined herein are produced by phosgenating diamines and isomer mixtures of diamines corresponding to the formula ##STR2## in which R.sup.1, R.sup.2, m and n are as defined herein. These diisocyanates which are liquid at room temperature and highly compatible with polyols are particularly useful in the production of polyurethanes.

Abstract: A diisocyanate corresponding to the formula ##STR1## in which R.sup.1, R.sup.2, R.sup.3, m and n are as defined herein is prepared by phosgenating a diamine corresponding to the formula ##STR2## in which R.sup.1, R.sup.2, R.sup.3, m and n are as defined herein. The diisocyanate may contain C.sub.1 -C.sub.12 -monoalkyl-substituted methylene-bis-(cyclohexylisocyanate)isomers in an amount of up to 40 wt. %. These new diisocyanates which are liquid at room temperature and compatible with polyols are particularly useful in the production of polyurethanes.

Abstract: Diisocyanates and isomeric mixtures of diisocyanates corresponding to the formula ##STR1## in which R.sub.1, R.sub.2, R.sub.3, m and n are as defined herein are made by phosgenating diamines corresponding to the formula ##STR2## in which R.sub.1, R.sub.2, R.sub.3, m and n are as defined herein at a temperature of from -20.degree. to 250.degree. C. These diisocyanates are particularly useful as starting materials for the production of polyurethanes by the isocyanate polyaddition process.

Abstract: The instant invention is directed to diisocyanates based on diphenylmethane which may be methyl-substituted and which are characterized in particular by isocyanate groups in the 3,4'- and optionally in the 3,2'-position. The instant invention is also directed to a number of independent processes for their production and to their use as isocyanate component in the production of polyurethanes.

Abstract: Diamines corresponding to the general formula ##STR1## wherein R.sup.1, R.sup.2 and R.sup.3 may be identical or different and represent hydrogen or straight- or branched-chain C.sub.1 -C.sub.12 alkyl groups, provided that two of the radicals,R.sup.1, R.sup.2 and R.sup.3, represent hydrogen, m and n each represent 0 or 1, provided that m+n=1; where m or n=0, the free valence is saturated by hydrogen, optionally in the form of isomeric mixtures, and optionally containing up to 35%, by weight, of the corresponding perhydrogenated diamines, and up to 10%, by weight, of the corresponding unhydrogenated aromatic diamines.Also, a process for preparing these diamines by catalytically-hydrogenating the corresponding aromatic diamines with 3 moles of hydrogen per mole of diamine, or catalytically-hydrogenating the corresponding dinitro compounds with 9 moles of hydrogen per mole of dinitro compound.

Abstract: The present invention relates to isocyanato-isocyanurates corresponding to the formula ##STR1## in which X.sub.1, X.sub.2 and X.sub.3 may be the same or different and represent radicals corresponding to the formula ##STR2## wherein R.sup.1 and R.sup.2 may be the same or different and represent hydrogen or C.sub.1 -C.sub.12 alkyl groups, and p is a whole or (on a statistical average) fractional number of from 1 to 5.The present invention also relates to a process for producing these isocyanato-isocyanurates and additionally relates to the use of the new isocyanato-isocyanurates, optionally blocked by blocking agents for isocyanate groups, as the isocyanate component in the produciton of isocyanate polyaddition products, preferably polyurethane lacquers.

Abstract: N-monosubstituted carbamic acid esters are thermally split on a continuous basis in a tube reactor. The carbamic acid ester which is flowed down or passed over the inner wall of a tube reactor is thermally split at a temperature of from 150.degree. to 450.degree. C. and under a pressure of from 0.001 to 20 bar into at least two fractions. One fraction is predominantly isocyanate and a second fraction is predominantly hydroxyl compound. These fractions may be separated by removing one as a gaseous fraction formed under the splitting conditions from the head of the reactor and collecting the second fraction as a liquid which accumulates at the base of the reactor. If both fractions are gaseous under the splitting conditions, they are both removed from the head of the reactor and subsequently separated by fractionating columns for example. This process is particularly advantageous in that isocyanate and hydroxyl fractions are obtained in high yield without using a solvent.