Dynamit Nobel Aktiengesellschaft

Helmut Aus Der Funten

Wilhelm Vogt

Gerhard Schade

Gerhard Bier

Klaus Schrage

Franz Blaschke

The present invention relates to the hydrogenation of phthalic acid anhydride to phthalide. A nickel catalyst of low nickel content is used as hydrogenation catalyst, and a benzoic acid alkyl ester as solvent. Small amounts of an alkanol can be added to the benzoic acid ester. On the basis of these specific conditions, the formation of by-products such as toluylic or phthalic acids in the hydrogenation is greatly diminished, and phthalide yields are obtained which, if the preferred conditions are maintained, can amount to as much as 90%.

Method of preparing phthalide

A process for preparing an alkali salt of d,l-phenylalanine and the free acid thereof is disclosed. According to the invention an alkali salt of phenylpyruvic acid is reacted at elevated pressure with hydrogen and ammonia in the presence of a noble metal catalyst of Group VIII. If the acid is desired it is obtained by acidification of the corresponding salt.

Method of preparing d,l-phenylalanine

A method has been invented for preparing phthalide by catalytic hydrogenation with a Periodic Table, Group VIII catalyst of a phthalide substituted in the 3-position by a hydroxyl, methoxy or acetoxy group.

Method for preparing phthalide by the catalytic dehalogenation of 3-chlorophthalide in the presence of hydrogenation catalyst and in the presence of an HCl acceptor. The phathalide which is produced is a valuable chemical intermediate for the manufacture of dyes, plant protecting agents and pharmaceuticals.

A polyamide composition, useful in the preparation of transparent sheets, having improved resistivity toward solvents containing moieties of terephthalic acid and 2-methylpentamethylenediamine, said polyamide characterized by a content of moieties of 2-ethyltetramethyldiamine and/or of isophthalic acid in a concentration totalling 15 to 30 mole percent, with respect to the sum of all diamine moieties or all dicarboxylic acid moieties, as the case may be.

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Niederkassel, Germany

Helmut Aus Der Funten