Societe Francaise Hoechst

Nobel Hoechst Chimie

Roussel Uclaf

Hoechst France

Hoechst Aktiengesellschaft

501 Societe Francaise Hoechst

Yani Christidis

Alain Schouteeten

Jean-Claude Vallejos

Christian Sidot

Robert Fournex

Michel Soreau

Colette Tournemine

Paul Mallo

Fernando Barzaghi

Michael Meier

Helmut Diery

Otto Mauz

Alain Blanc

Dominique Depernet

Pierre Gallezot

Alain Perrard

Jean Claude Vallejos

Philippe Gallois

Suzanne Maximovitch

Marie-Jeanne Barbier

Eberhard Prinz

Isabelle Gimenez

Emmanuel Herman

Preparation process for 2-coumaranone in which glyoxylic acid, in vapor phase, is reacted with cyclohexanone, in the presence of a dehydrogenation catalyst.

Preparation method for 2-coumaranone

Azines of formula (I): ##STR1## in which R and R' either are identical and represent an alkyl radical containing 1 to 4 carbon atoms or an alkenyl radical containing 3 to 5 carbon atoms, or together form a radical of formula (II):

Acetaldehyde derivatives, their preparation process and their use

Preparation process for a product of formula (I): ##STR1## in which R.sub.1 and R.sub.2, either are identical and represent a C.sub.1 -C.sub.4 alkyl radical, or form together a group of formula (II):

Preparation process for 2 formyl imidazole acetals

Process for the of aromatic carboxamides from aromatic carboxylic acids and urea Process for the preparation of aromatic carboxamides of the formula (I) ##STR1## in which R.sub.1, R.sub.2, and R.sub.3 are identical or different and are hydrogen, fluorine, chlorine or bromine atoms, or are alkyl(C.sub.1 -C.sub.4), hydroxyl or nitro groups, or R.sub.1 and R.sub.2 form an aromatic ring of 5 or 6 ring members, which ring may be substituted by fluorine, chlorine or bromine atoms or by alkyl(C.sub.1 -C.sub.4), hydroxyl or nitro groups, which involves reacting aromatic carboxylic acids of the formula (II) ##STR2## in which R.sub.1, R.sub.2 and R.sub.3 are as defined above with urea in an inert organic solvent with the addition of a catalytic amount of phosphorous acid.

Process for the preparation of aromatic carboxamides from aromatic

Preparation process for a hydroxyphenylacetic acid of formula (I): ##STR1## where R.dbd.H, alkyl or alkoxyl as well as its salts, in which the corresponding free or salified hydroxymandelic acid of formula (II): ##STR2## in which R has the meaning given previously and M.dbd.H, K or an ammonium group is reacted in an aqueous medium, at a temperature greater than or equal to 50.degree. C., with formic acid in the presence of catalytic quantities of an oxygenated derivative of sulphur having a degree of oxidation from 2 to 4, in order to obtain the hydroxyphenylacetic acid of formula (I) which is isolated or, if desired, is salified according to the usual methods and the hydroxyphenylacetic acid thus obtained.

Preparation process for hydroxyphenylacetic acids

Diallyloxyacetic acid and its basic addition salts, their preparation process and their application as cross-linking agents. Diallyloxyacetic acid and its basic addition salts, preparation process and application as cross-linking agents.

Method of cross-linking ethylene monomers using diallyloxyacetic acid

Preparation process for orthohydroxymandelic acid, as well as its salts, in which glyoxylic acid is reacted with phenol in the presence of a tertiary amine and catalytic quantities of trivalent metal cations, in order to obtain the expected product which is isolated and, if desired, salified.

Process for obtaining orthohydroxymandelic acid and its salts

Preparation process for 5-(2-thenyl) hydantoin in which 5-(2-thenylidene) hydantoin is reacted in acetic acid with a phosphorous compound selected from the group consisting of red phosphorus and phosphonic acid, in the presence of a catalytic amount of an iodine compound selected from the group consisting of iodine and hydroiodic acid.

Process for reducing 5-(2-thenylidene) hydantoin to 5-(2-thenyl)

Process for obtaining an arylacetic acid of general formula (I):

Preparation process for arylacetic acids and their alkali metal salts

Transvinylation process between vinyl acetate or vinyl propionate and a carboxylic acid of general formula (I),

Transvinylation of carboxylic acids

Preparation process for piperonal by decarboxylating oxidation of 3,4-methylenedioxy mandelic acid by nitric acid in aqueous medium in the presence of hydrochloric acid.

Preparation process for piperonal

The invention relates to the preparation of glyoxylic acid by oxidizing an aqueous solution of glyoxal having a pH less than 1 with molecular oxygen in the presence of nitrogen monoxide as a catalyst. This process allows the practically total conversion of the starting glyoxal with a good yield of glyoxylic acid.

Process for the manufacture of aqueous solutions of glyoxylic acid

The invention provides an improved process for the manufacture of alkyl pyruvates having general formula (I):

Process for the manufacture of alkyl pyruvates

This process is characterized by the fact that glyoxylic acid in aqueous solution is reacted with an excess of phenol in the presence of a tertiary amine, insoluble or slightly soluble in water and liquid at ambient temperature, in particular tributylamine or triisooctylamine, then the parahydroxymandelic acid thus obtained is salified with sodium hydroxide in aqueous solution. The reaction of the glyoxylic acid with phenol is carried out at a temperature between 15.degree. C. and 80.degree. C.

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Paris, France

Yani Christidis