Evonik Operations Gmbh

Evonik Oxeno Gmbh & Co. Kg

Thomas Schneider

Michael Grass

Horst-Werner Zanthoff

Johannes Kraft

Johan Anton

Lena Altmann

Julia Bauer

Ralf Klaus Hinsken

Grzegorz Ziomek

Dietmar Gubisch

A process discharges low boilers during production of dialkyl terephthalates or dialkyl phthalates having C8 to C11 alkyl radicals. The production is carried out using a C8 to C11 alcohol or a mixture of two or more C8 to C11 alcohols in one or more reactors. The low boilers formed during the reaction are separated off by an efficient process and thus cannot accumulate.

Process for discharging low boilers during the production of dialkyl terephthalates or dialkyl phthalates

The invention provides a process for regenerating a catalyst used for the hydrogenation of an aromatic species, consisting of several steps. First the system is purged with nitrogen, then air is metered in stepwise, and the addition of nitrogen is subsequently ended until only air is present.

Process for regeneration of hydrogenation catalysts

A process prepares dialkyl 1,4-cyclohexanedicarboxylates by ring hydrogenation of the corresponding dialkyl terephthalate having a CO value of less than 0.3 mg KOH/g. The dialkyl 1,4-cyclohexanedicarboxylates thus produced can be used as plasticizers or as a component of a plasticizer composition for plastics, in particular PVC.

Process for preparing dialkyl 1,4-cyclohexanedicarboxylates

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Schermbeck, Germany

Thomas Schneider