Basf Aktiengesellschaft

Hans Hellbach

Franz Merger

Friedrich Towae

Gerhard Nestler

Rolf Platz

Karl Gerhard Baur

Norbert Rieber

Peter Stops

Volker Diehl

Erwin Brunner

Waldemar Koehler

Gunther Isbarn

Kurt Taglieber

Guenter Mueller

Gerhard Hunziker

A process for the preparation of nicotinamide by amidation of a nicotinic acid/nicotinamide melt, vacuum distillation of the amidation mixture, removal of the nicotinamide as the bottom product and recycling of the top product, depleted with respect to nicotinamide, into the amidation stage together with addition of fresh amounts of nicotinic acid.

Preparation of nicotinamide

Hexamethylene 1,6-diisocyanate and/or isomeric aliphatic diisocyanates where alkylene is of 6 carbon atoms, preferably 2-methylpentamethylene 1,5-diisocyanate and/or 2-ethyltetramethylene 1,4-diisocyanate, are prepared by a process wherein the corresponding dialkylurethanes are vaporized, without decomposition, at from 220.degree. to 300.degree. C., advantageously under reduced pressure, the dialkylurethane vapors are subjected to thermal cleavage under reduced pressure, preferably from 0.1 to 200 mbar, and at above 300.degree. C., preferably from 310.degree. to 480.degree. C. The cleavage products are fractionally condensed with the product obtained in the first condensation stage consisting predominantly of the diisocyanates, while that obtained in the second condensation stage is the alcohol.

Preparation of hexamethylene 1,6-diisocyanate and/or isomeric

This invention discloses a non-phosgene process for the preparation of 3-isocyanatomethyl-3,5,5-trimethylcyclohexylisocyanate by the reaction of the precursor diamine with urea and an aliphatic alcohol in the presence of a dialkyl carbonate and an alkyl carbonate. The intermediate diurethane is separated from starting materials and by-products and thermally cleaved to alcohol and diisocyanate which are separated by fractional condensation of the products from the vapor state. This process gives high yields of the desired diisocyanate and lends itself particularly to continuous processing.

Multiple-step process for the preparation of

Hexamethylene diisocyanate and/or isomeric alkylene diisocyanates having 6 carbon atoms in the alkylene radical, preferably 2-methylpentamethylene 1,5-diisocyanate and/or 2-ethyltetramethylene 1,4-diisocyanate are prepared without the use of phosgene in a multiple-step process by means of

Multiple-step process for the preparation of hexamethylene

A process for the safe supply of molecular oxygen or gas containing molecular oxygen to an oxidation of hydrocarbons in the liquid phase, wherein, immediately before the point of entry into the liquid hydrocarbon, the oxygen, or gas containing oxygen, to be supplied is at least 20.degree. C. colder than the hydrocarbon, and wherein, as soon as the oxygen, or gas containing oxygen, which is to be supplied exceeds the predetermined temperature at the supply orifice, the supply ceases.

Process and apparatus for the safe supply of molecular oxygen or of gas

Organic isocyanates, preferably alkyl, mono-, di- and/or polyisocyanates or aryl-mono-, di- and/or polyisocyanates, are prepared by thermally cleaving the corresponding urethanes at temperatures of 175.degree. C. to 600.degree. C. in the presence of carbon, preferably in an agitated carbon bed or in a fluidized bed containing carbon.

Process for the preparation of isocyanates by thermal cleaving of

Alkylphenols are manufactured by reacting phenols with olefins, stripping the reaction mixture by means of an inert gas, cooling the phenol-containing gas mixture and removing the unconverted phenol. The products are starting materials for the manufacture of dyes, pesticides, pharmaceuticals, emsulfiers, dispersing agents, stabilizers, antioxidants, plasticizers, corrosion inhibitors, disinfectants, seed dressings, stabilizers against ageing, crop protection agents and scents.

Growing community of inventors

Lampertheim, Germany

Hans Hellbach