Abstract:
Die Erfindung betrifft Verfahren zur Herstellung von rieselfähigen Dicarbonsäure-Kristallisaten aus einer wässrigen Lösung oder Suspension der Dicarbonsäure in einem Kristallisator.
Abstract:
The invention relates to methods for producing free flowing dicarboxylic acid crystalline crops from an aqueous solution or suspension of the dicarboxylic acid in a crystallizer.
Abstract:
The present invention relates to a process for preparation of polysulphones with Yellowness Index to DIN 6167 smaller than 19 and of polyether sulphones with Yellowness Index to DIN 6167 smaller than 30, characterized in that the polymerization reaction is carried out in basic, aprotic solvents, using a mechanical agitator which passes close to the wall. The present invention also relates to the polyether sulphones and polysulphones obtainable for the first time by this process, and to the use of these polymers for production of mouldings, foils, membranes and foams.
Abstract:
The invention relates to a method for producing biphenols of general formula (I) by reacting monophenols of general formula (II), wherein the radicals R1, R2 and R3 independently represent hydrogen, alkyl, aryl or arylalkyl, with 1 - 10 C-atoms, in the presence of an oxidation agent in a reactor. Said method is characterised in that a) the reactor does not contain any stationary integrated components which act as a current agitator, b) a maximum of 0,6 mol of oxidation agents are used per mol of monophenol, and c) the oxidation agent is added in a continuous or discontinuous manner in a plurality of portions within a time span of between 10 min - 24 hours, whereby the amount of oxidation agent which is added per time unit is not constant over the entire tine span, but is varied.