Abstract: Stable NCO prepolymers are produced from polyisocyanates having a melting point greater than 70° C., preferably, naphthalene diisocyanate, having advantageous physical properties. An important feature of the process of the present invention is the rapid cooling of the prepolymer. The process of the present invention may be carried out on a continuous or batch basis. The prepolymers of the present invention are particularly suitable for the production of cast polyurethane elastomers.

Abstract: Stable NCO prepolymers are produced from polyisocyanates having a melting point greater than 70° C., preferably, naphthalene diisocyanate, having advantageous physical properties. An important feature of the process of the present invention is the rapid cooling of the prepolymer. The process of the present invention may be carried out on a continuous or batch basis. The prepolymers of the present invention are particularly suitable for the production of cast polyurethane elastomers.

Abstract: Durene diisocyanate is prepared by reacting durene with nitric acid in sulfuric acid, catalytic hydrogenation of the dinitrodurene that is formed, and phosgenation of the resultant durene diamine in a conventional manner. The intermediate products dinitrodurene and durene diamine do not have to be worked up in a complicated manner as solid products, but can be worked up in dissolved form. The intermediate products dinitrodurene and durene diamine do not have to be isolated and purified in a complicated manner. but can be processed directly after preparation. Another advantage of this process is that only a single organic solvent need be used for the overall preparation process. Separation and re-use of spent acid in the conversion of durene with nitric acid also renders the process of the present invention significantly less environmentally harmful than the known processes of the prior art.

Abstract: The present invention relates to an improved process for the preparation of toluidines. This process comprises the reductive deamination of 2,3-diaminotoluenes and/or 3,4-diaminotoluenes in the presence of one or more iron oxide catalyst.

Abstract: Diisocyanates containing carboxylic acid ester groups corresponding to the formula: ##STR1## in which R and R.sup.1 represent specified groups are produced by phosgenation of the corresponding diamines, optionally present in the form of an ammonium salt. These diisocyanates are useful as starting materials in the production of plastics containing urethane and/or urea groups and as starting materials for the production of intermediate products used for the production of such plastics.

Abstract: This invention relates to a process for the preparation of highly pure aromatic diurethanes and/or polyurethanes by reaction of the corresponding aromatic diamines and/or polyamines with unsubstituted carbamates with the release of ammonia. The reaction is carried out in the presence of excess carbamates. The resultant reaction mixture is freed from any solvents used, and the formed aromatic diurethanes and/or polyurethanes are purified by extraction with water.

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: 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: Cycloaliphatic triisocyanates or isomer mixtures of such triisocyanates corresponding to the formula ##STR1## in which R represents hydrogen or a C.sub.1 -C.sub.4 alkyl group are produced by phosgenating the corresponding cycloaliphatic triamines or isomer mixtures of such triamines or a salt thereof.These triisocyanates are useful in the production of polyisocyanate addition products, particularly polyurethane coatings and lacquers.

Abstract: Triisocyanates and isomeric mixtures of triisocyanates corresponding to the formula ##STR1## in which R represents hydrogen or an alkyl group having from 1 to 4 carbon atoms are made by phosgenating the corresponding triamine. These triisocyanates are particularly useful in the production of polyurethanes, especially polyurethane lacquer coats.

Abstract: Low molecular weight N- and O-substituted diurethanes and/or polyurethanes are prepared by reacting a diamine and/or polyamine containing a primary amino group with an N-aryl-0-alkyl urethane in the presence of at least one high boiling alcohol. This reaction may be carried out at a temperature of from 180.degree. to 350.degree. C. and a pressure of approximately 0.1 to 1,500 mbar. The arylamine corresponding to the N-ary-0-alkyl urethane which forms during this reaction is continuously removed from the reaction mixture.

Abstract: A process for the preparation of N,O-disubstituted urethanes. A substituted urea, an alcohol and a compound taken from the group consisting of N-unsubstituted urethanes, urea, polyurets and mixtures thereof at a temperature of 120.degree.-350.degree. C. The urethanes prepared by this process are particularly suitable for the preparation of isocyanates.