Hoechst Aktiengesellschaft

Klaus Schmiedel

Franz Landauer

Wolfgang Hesse

Siegbert Rittner

Georg Schaeffer

Rudolf Lademann

Ulrich Girrbach

Siegfried Bildstein

Heinrich Lenzmann

Wolfram Schwiersch

Alwin Topp

The invention relates to a process for the separation and recovery of naphthalenesulfonic acids from aqueous solutions. In this, the naphthalenesulfonic acids are adsorbed on basic ion exchangers and subsequently desorbed again, preferably with the aid of an alkaline liquor, from which the alkali metal sulfonates are then precipitated by cooling.

Process for the separation and recovery of naphthalene-sulfonic acids

A process for the preparation of synthetic resins based on resorcinol compounds which comprises reacting a resorcinol pitch which is obtained in the manufacture of resorcinol from benzenedisulfonic acid in at least one step with an oxo-compound selected from aldehydes, ketones and compounds based on or splitting off at least one of these substances, and the use of the products as binders for abrasive articles.

Process for the preparation of synthetic resins based on resorcinol

The waste water being formed upon the preparation of hydroxy aromatics, preferably of resorcinol and .beta.-naphthol, by caustic alkaline melt of the corresponding aryl-sulfonic acids or aryl sulfonates is purified by wet oxidation with oxygen or oxygen-containing gases at temperatures of from about 100.degree. to 370.degree. C. and under a pressure of from about 1 to 300 bars. The COD-decomposition rates amount to about 90% and more. When a hydroxy aromatic is prepared by means of a caustic soda melt, this process provides a sulfate, especially sodium sulfate, which is of sufficient purity for further use without complementary purification stages. The obtention of the pure salt is important for the economy of the process.

Process for the purification of waste water

Continuous preparation of mono- or di-(trichloromethyl)-benzenes or of mono- or di-(trichloromethyl)-benzenes substituted in the benzene ring by halogen atoms from the corresponding mono- or dimethylbenzenes and chlorine in several steps with radiation by means of rays of high energy, is effected by reacting mono- or dimethylbenzene with chlorine in 4 to 14 steps, at a temperature in the range of from 20.degree. to 130.degree. C, whereby chlorine is introduced into the second step and the following steps, the resulting waste gas is introduced into step 1 and chlorine contained in the waste gas is reacted in reactor 1 with fresh mono- and dimethylbenzene. A preferred embodiment for carrying out the process is reaction in a reactor arrangement in cascade form, wherein the number of steps corresponds to the number of reactors and wherein as reactors circulation reactors are used.

Process for the continuous preparation of mono- or

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Konigstein, Germany

Klaus Schmiedel