Hoechst Aktiengesellschaft

Hoecht Ag

Thomas Gerdau

Hans-Jerg Kleiner

Martin Bruck

Marcellus Peuckert

Fritz Aldinger

Tilo Vaahs

Holger Borchert

Jens Weiguny

Georg Pawlowski

Matthias Beller

Alwin K Reng

Hartmut Fischer

Peter Gross

Walter Kunz

The invention relates to a process for the preparation of substituted 3-arylquinazoline-2,4-diones of the formula (I) ##STR1## in which R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are as defined in claim 1 and Ar is ##STR2## where R.sup.5 to R.sup.9 are as defined in claim 1, by reacting a compound of the formula (II) ##STR3## with a compound Z in the presence of a catalyst, a ligand and a solvent, where Z is

Process for the preparation of substituted 3-arylquinazoline-2,4-diones

A process for the preparation of N-acylglycine derivatives of the formula (I) ##STR1## which comprises reacting a carboxylic acid amide with an aldehyde in the presence of a solvent and an acid to give an acylaminomethylol and then carbonylating the acylaminomethylol in the presence of a cobalt carbonyl catalyst.

Process for the preparation of N-acyl-.alpha.-amino acid derivatives

The invention relates to a process for the preparation of halobenzaldehydes of the formula (I): ##STR1## in which Hal is fluorine, chlorine, bromine or iodine and z=1, 2, 3 or 4, by catalytic gas-phase oxidation of a substituted toluene of the formula (II), ##STR2## by oxygen, which comprises carrying out the oxidation in the presence of a catalyst of the formula (III)

Process for the preparation of halobenzaldehydes

Process for the preparation of aldehydes by catalytic gas phase hydrogenation of carboxylic acid or their derivatives with the aid of a tin catalyst The invention relates to a process for the preparation of aldehydes by catalytic gas phase hydrogenation of carboxylic acids or carboxylic acid derivatives at elevated temperature, which comprises employing at tin catalyst supplied to an oxidic support material.

Process for the preparation of aldehydes by catalytic gas phase

The invention relates to alkyl ether carboxylic acid taurides of the formula

Alkyl ether carboxylic acid taurides

The invention relates to novel polymeric hydridochlorosilazanes, to their preparation, to their processing to form ceramic materials containing silicon nitride, and to said materials themselves. The polymeric hydridochlorosilazanes are prepared by reacting oligohydridoorganosilazanes of the general formula (R.sup.1 SiHNH).sub.n, in which n is about 3 to about 12, with at least one of the chlorosilanes R.sup.2 SiHCl.sub.2, R.sup.3 SiCl.sub.3, Cl.sub.2 R.sup.4 Si--CH.sub.2 CH.sub.2 --SiR.sup.4 Cl.sub.2 or Cl.sub.3 Si--CH.sub.2 CH.sub.2 --SiR.sup.5 Cl.sub.2 at 30.degree. C. to 300.degree. C., where the radicals independently of one another have the following meanings:

Polymeric hydridochlorosilazanes, process for their preparation, ceramic

The invention relates to a process for the production of a ceramic/fiber composite. The process comprises impregnating fibers with a molten polysilazane in a first step, converting the polysilazane in the fibers into the infusible state in a second step and, in a third step, heating the impregnated fibers to 800.degree. to 2000.degree. C. in an atmosphere of nitrogen, noble gas, or ammonia.

Process of producing a ceramic/fiber composite using a molten

The invention relates to novel polymeric hydridosilazanes, their preparation, their conversion into silicon nitride-containing ceramic material, and this material itself. To prepare the polymeric hydridosilazanes, polymeric hydridothiosilazanes are reacted with NH.sub.3. To prepare the silicon nitride-containing ceramic material, the polymeric hydridosilazanes are then pyrolyzed.

Polymeric hydridosilazanes, processes for the preparation thereof,

The invention relates to a novel sinterable ceramic powder, to its preparation, to its processing to form silicon nitride ceramic and to said material itself and its use. The sinterable ceramic powder is prepared by dissolving the polysilazane of formula (I)

Sinterable ceramic powder, process for its preparation, silicon nitride

The invention relates to a process for the production of ceramic material containing silicon nitride, such as fibers, coatings or moldings. In this process, polymeric hydridochlorosilazanes are rendered infusible at a temperature below their softening point by treatment with gaseous NH.sub.3 and are then pyrolyzed in an atmosphere containing NH.sub.3 at 700.degree. to 1500.degree. C. Fibers, coatings or moldings containing silicon nitride are produced by first producing appropriate structures from a melt of the polymeric hydridochlorosilazane and then rendering them infusible and pyrolyzing them.

Process for the production of ceramic material containing silicon

The invention relates to novel polymeric hydridosilazanes, processes for their preparation and their use for the preparation of ceramic material containing silicon nitride. To prepare the polymeric hydridosilazanes, polymeric hydridochlorosilazanes are reacted with NH.sub.3. To prepare the ceramic material containing silicon nitride, the polymeric hydridosilazanes are then pyrolyzed.

Polymeric hydridosilazanes and processes for their preparation, and

The invention relates to novel polymeric hydridochlorosilazanes and a process for their preparation. The compounds according to the invention can be converted into polyhydridosilaznes by reaction with ammonia, and these can in turn be pyrolyzed to ceramic material containing silicon nitride. To prepare the polymeric hydridochlorosilazanes, oligohydridoalkylsilazanes (R.sup.1 SiHNH).sub.n are reacted with a dichlorohydridoalkylsilane R.sup.2 SiHCl.sub.2.

Polymeric hydridochlorosilazanes and processes for their preparation

A process for the production of alkali-phosphonoformates which comprises bringing together in a first stage a trialkyl ester of phosphonoformic acid and an aqueous solution of an alkali hydroxide at a temperature in the range from the freezing point of water and about 40.degree. C., either keeping the resulting mixture in a second stage for further progress of the reaction and then heating the reaction mixture in a third stage to a temperature up to about 100.degree. C. for completion of the saponification, or heating the reaction mixture immediately for completion of the saponification to a temperature of up to 100.degree. C.

Process for the preparation of alkali metal phosphonoformates

Polymeric hydridosilazanes, processes for the preparation thereof, silicon nitride-containing ceramic materials which can be prepared therefrom, and the preparation thereof. The invention relates to novel polymeric hydridosilazanes, their preparation, their conversion into silicon nitride-containing ceramic material, and this material itself. To prepare the polymeric hydridosilazanes, polymeric hydridothiosilazanes are reacted with NH.sub.3. To prepare the silicon nitride-containing ceramic material, the polymeric hydridosilazanes are then pyrolyzed.

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Eppstein, Germany

Thomas Gerdau