Dynamit Nobel Aktiengesellschaft

Wolfgang Wolfes

Gunter Bison

Walter Heinzelmann

Norbert Linkat

Erich Behr

Josef Winterscheid

Reiner Elfgen

Kurt Breideneichen

A process for the preparation of 1H-tetrazole-1-acetic acid or its ester which comprises contacting trimethylsilyl azide with an orthocarboxylic acid ester of the formula

Process for the preparation of 1H-tetrazole-1 compounds using

A process for the preparation of racemic phenylethylamine which comprises contacting an optical antipode therefore, e.g., L(-) or D(+)-1-phenylethylamine with sodium amide or sodium hydride.

Method of racemizing optically active 1-phenylethylamine

A process for splitting the L-(-)-.alpha.-phenylethylamine salt of D-(-)-.alpha.-azidophenylacetic acid which comprises the steps of mixing the salt with a liquid diluent and an acidic cation exchange material, effecting agitation of the resulting admixture and therefore isolating a highly purified D-(-)-.alpha.-azidophenylacetic acid. This acid product is characterized by an amine content of less than 0.2% by weight.

Process for splitting the L-(-)-.alpha.-phenylethylamine salt of

A process for the preparation of a thermostable polyester which is insoluble in tetrachloroethane and consists of about 40 to 200 units, said polyester having units of the formula ##STR1## combined with units of the formula ##STR2## wherein Ph is ##STR3## AND BOTH R radicals are methyl on some units and both R radicals are phenyl on the balance of the units, said methyl units comprising 5-30 mole percent of the total R-containing units which comprises heating and condensing in the absence of a catalyst 4,4'-dihydroxytetraphenylmethane having a melting point of at least 295.degree. C together with 2,2-bis-(4-hydroxyphenyl)-propane and terephthalic or isophthalic acid dichloride until there is prepared said polyester which is insoluble in tetrachlorethane.

Thermostable polyester

Process for producing tetrazole-1-acetic acid of maximum purity includes the steps of providing a crude reaction product containing an alkyl ester of tetrazole-1-acetic acid having from 1 to 4 carbon atoms in the alkyl group, effecting molecular distillation of this reaction product at a temperature below 130.degree.C. under a vacuum of 10.sup.-.sup.1 torr to obtain a distillant containing the alkyl ester and then gently hydrolyzing the resultant distillate to obtain the desired acid product.

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Niederkassel-Mondorf, Germany

Wolfgang Wolfes