Hoechst Aktiengesellschaft

Cassella Aktiengesellschaft

Manfred Mayer

Friedrich Engelhardt

Ulrich Riegel

Fritz Engelhardt

Siegbert Rittner

Uwe Nickel

Bernhard Wojtech

Gerhard Noltner

Uwe Stuven

Ulrich Kussmaul

Wolfgang Strobel

Uwe St&uuml;ven

Karl-Erich Ott

Edgar Wetzel

Rolf Bader

Hartmut Last

Roland Volz

Rudolf Nowack

The present invention relates to a process for modifying hydrophilic polymers by mixing with a modifier, characterized in that the pulverulent polymer and the modifier are introduced continuously into a vertical, cylindrical mixer, mixed at a power of from 1,000 to 5,000 Wh/m,of powder by means of rotating blades at a blade rate of from 100 to 300 s,at a residence time of 1-10 seconds, during which the powder is passed through zones having energy dissipation densities of 300-600 W/l of mixer volume.

Process for modifying hydrophilic polymers

The present invention relates to a process for the preparation of hydrophilic hydrogels of high swelling capacity by (co)polymerization of hydrophilic monomers in a fluidized bed apparatus.

Process for the preparation of hydrophilic hydrogels of high swelling

The present invention relates to hydrophilic, swellable graft polymers which comprise, in a random distribution, from 0.5 to 50% by weight of radicals of the general formula I ##STR1## and radicals of the general formula II ##STR2## from 49 to 99% by weight of radicals of the general formula III ##STR3## containing an acid group, and from 0.1 to 2% by weight of radicals of a crosslinking agent which are derived from monomers containing at least two olefinically unsaturated double bonds, where the radicals R.sup.1 to R.sup.4, X and Y and n and m are where X and Y, independently of one another are COCH.sub.3, CH.sub.2 COOR.sup.2, COCH.sub.2 CH.sub.2 COOH ##STR4## n and m, independently of one another, are 2 to 300, R.sup.1 is hydrogen or methyl, R.sup.2, independently of one another, are hydrogen, methyl or ethyl, R.sup.3 is the carboxyl group, the sulphonyl group, the phosphonyl group, which is optionally esterified by means of alkanol having 1 to 4 carbon atoms, or a group of the formula ##STR5## to the preparation thereof, and to the use thereof as absorbents for water and aqueous solutions.

Hydrophilic, swellable graft polymers

The invention relates to a process for separating dimethyl isophthalate (DMI) and dimethyl orthophthalate (DMO) and other by-products from their mixture with dimethyl terephthalate (DMT), formed in the oxidation of p-xylene followed by esterification with methanol, by crystallization from the melt. Initially, the esterification product is here distilled once or several times. The DMT-rich fraction obtained is then subjected wholly or partially to one or several crystallizations from the melt, and the DMI-DMO fraction thus obtained is at least partially removed from the system. As an alternative, the DMT-rich fraction is first recrystallized from methanol, the methanol is then evaporated from the mother liquor and the remaining residue is subjected to one or several crystallizations from the melt. The DMI-DMO fraction thus obtained is again at least partially removed from the system.

Process for separating dimethyl isophthalate and dimethyl orthophthalate

The invention relates to a process for extracting phenols from aqueous solutions. The extractant used is a salt of an aliphatic amine, having a total carbon number of at least 10, and a strong acid.

Process for extracting phenols from aqueous solutions

The rectifier having inserts for evaporation and condensation is constructed on the basis of modules (19). Each module has a distributor channel (5) for the liquid. The distributor channel (5) is positioned above the upper rim of an evaporater (1) inclined in the direction of the module axis. The evaporator (1) ends above a guide element (13) for the liquid. The guide element (13) is inclined in the direction of the module wall (14) and ends above the distributor channel (5) of the next module. The module is furthermore provided with a guide element (2) for the vapor and a condenser (10). The condenser (10) has drain elements (11, 15) for the condensate.

Rectifier

The invention relates to a process for improving the processing properties of powdery polyolefins. It is endeavored by this process to obtain a polyolefin powder which can be processed on screw extruders to an almost bubble-free product. The polyolefin powder is heated to a temperature of between 40.degree. C. and its melting point and introduced into a gap between two gap-forming elements. In this gap, the powder is compressed with a pressure of from 0.1 to 10 t per cm of gap length, and the powder so compressed is then comminuted.

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Niedernhausen, Germany

Manfred Mayer