Dynamit Nobel Aktiengesellschaft

Otto W Bleh, Deceased

Otto Ackermann

Walter Rogler

Heinrich Bunger

Dieter Morgenstern

A process for producing dimethyl terephthalate from high-boiling tarry residues from the combined oxidation of p-xylene and p-toluate in the liquid phase, esterification of the resulting acids with methanol and separation of the resulting dimethyl terephthalate which include the steps of subjecting the high-boiling residues to treatment with methanol at temperatures above 250.degree. C. and thereafter separating the resulting dimethyl terephthalate in accordance with conventional separation techniques.

Process for the preparation of dimethyl terephthalate

Preparation of alkoxymethylene malonic acid ester of formula: ##STR1## wherein R and each R' is an alkyl group, by reaction of malonic acid diester and ortho formic acid triester. The reaction is performed in the presence of a carboxylic acid or a carboxylic acid anhydride and a Lewis acid. The ortho ester is initially present in amount of at least 1,4 mols per mole of the malonic acid ester starting material. Alcohol formed during the reaction is removed during the reaction.

Method of preparing alkoxymethylenemalonic acid esters

A process for preparing a pyridylaminomethylenemalonic acid derivative of the formula: ##STR1## which comprises reacting together a pyridyl compound of the formula: ##STR2## an alkoxy compound of the formula: ##STR3## and a malonic acid derivative of the formula selected of the group of ##STR4## wherein: R.sub.5 and R.sub.7 are the groups -- OOR.sub.4 or OOR.sub.5 or .tbd.N

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Troisdorf-Bergheim, Germany

Otto W Bleh, Deceased