Basf Aktiengesellschaft

Manfred Dimmler

Wolfgang Reuther

Gerhard Hoffmann

Martin Fischer

Thomas Wettling

Erhard Guenther

Klaus Diehl

Dieter Buhl

Bernd Hupfeld

Jochem Henklemann

A multi-stage catalytic process for preparing a 2-(4-hydroxyphenoxy)-propionate, especially methyl 2-(4-hydroxyphenoxy)-propionate, with a purity greater than 99% by esterifying the corresponding 2-(4-hydroxyphenoxy)-propionic acid with an excess amount of alcohol, e.g. methyl alcohol, in a series of at least 2 up to 10 sequential stages at temperatures of 20.degree. to 150.degree. C. and pressures of 0.05 to 5 bar in the presence of a distillable acid catalyst such as hydrochloric acid or hydrogen chloride. In a first esterification stage, unreacted alcohol is removed from the ester product in vacuo at temperatures of 30.degree. to 100.degree. C. together with other volatile components, including the acid catalyst. Without a separate purification of the resulting ester as the bottoms product of the first stage, the esterification step is repeated in at least one additional stage. The final ester product of this multi-stage process is characterized by a water content of less than 0.1%, a halide content of less than 100 ppm, an organic halogen content of less than 50 ppm and a content of all other contaminating compounds of less than 0.1%.

Preparation of 2-(4-hydroxyphenoxy) propionates

A process for the preparation hydroxyoxaalkylmelamines of the general formula I ##STR1## in which R.sup.1 denotes a residue of the general formula II ##STR2## in which the radicals R' can be the same or different and stand for hydrogen or C.sub.1 -C.sub.4 alkyl and n denotes 2 or 3 and the radicals R.sup.2 and R.sup.3 stand for one of the radicals R.sup.1 or hydrogen, by the reaction of melamine with a compound of the general formula III ##STR3## in which R' and n have the meanings stated above, at a temperature of from 120.degree. to 250.degree. C. and in the presence of an acid catalyst, in which the acid catalyst is used in a concentration of from 0.01 to 0.15 mol and preferably from 0.02 to 0.12 mol and more preferably from 0.03 to 0.1 mol, based on 1 mol of melamine.

Preparation of hydroxyoxaalkylmelamines

A process for preparing indolenines of the formula I ##STR1## where R.sup.1, R.sup.2 and R.sup.3 are independently of one another hydrogen, C.sub.1 -C.sub.20 -alkyl, C.sub.2 -C.sub.20 -alkenyl, C.sub.3 -C.sub.8 -cycloalkyl, aryl, C.sub.7 -C.sub.20 -alkylphenyl, C.sub.7 -C.sub.20 -phenalkyl, or R.sup.1 and R.sup.2 or R.sup.1 and R.sup.3 together are an unsubstituted or C.sub.1 -C.sub.12 -alkyl-substituted C.sub.3 -C.sub.8 -alkylene chain,

Preparation of indolenines

An electrophotographic recording medium which consists essentially of an electrically conductive base and a photosemiconductive double layer which comprises a first layer containing charge carrier-producing dyes, and a second layer containing one or more compounds which are charge carrier-transporting when exposed to light, wherein the charge carrier-producing dyes are those of the general formula I ##STR1## where R.sup.1, R.sup.2 and R.sup.3 are each hydrogen, halogen, alkyl, nitro or cyano, R.sup.4 is phenyl, halophenyl, alkylphenyl, nitrophenyl or dialkylaminophenyl, and X is oxygen, sulfur, NH or N-phenyl, and the production of this recording medium.

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Dannstadt-Schauernheim, Germany

Manfred Dimmler