Degussa Aktiengesellschaft

Wolfgang Kunkel

Gustaaf Goor

Jorg Kemnade

Ulrich Brand

Dietrich Schneider

Hans Birkenbeil

A method is shown for the separation of catalyst-free working solution from working solution, containing noble-metal black, especially palladium black as catalyst, of the hydrogenation cycle of the so-called anthraquinone method for the production of hydrogen peroxide by filtration of the catalyst-containing working solution using filter candles. The filter candles are formed of an open-pore support body based on a carbon material or metallic or ceramic material with an average pore width in a range of 5 to 100 .mu.m and of a single-layer or multi-layer membrane of ceramic material with an average pore width in a range of at least about 1 up to 10 .mu.m located on the outside surface of the support body.

Method of separating catalyst-free working solution from the

An aqueous hydrogen peroxide extract which contains small amounts of dispersed working solution and a working solution which contains small amounts of dispersed aqueous hydrogen peroxide are collected in the extraction stage of the anthraquinone method for preparing hydrogen peroxide. In order to purify these solutions, the working solution is compounded with aqueous hydrogen peroxide or preferably with water and the hydrogen peroxide extract is compounded with an organic dissolving mixture, preferably a quinone dissolver, and the respective dispersed phase is separated out with the aid of coalescers in a separator unit. It is especially preferable to add 1-3% by volume water or 1-3% quinone dissolver before the coalescer stages and to use coalescers with a drop-enlarging design and filter layers consisting of thermally desized glass filament yarn. The after-purification in accordance with the method results in a hydrogen peroxide which is improved as regards carbon content and color index as well as in an increase in yield of hydrogen peroxide and in a working solution with constant rel. moisture.

Method of preparing hydrogen peroxide

There is provided a continuous parallel current flow process for carrying out the catalytic hydrogenation with hydrogen or a hydrogen containing gas for the production of hydrogen peroxide in the anthraquinone process using palladium black suspended in the working solution at a temperature up to 100.degree. C. and a pressure up to 15 bar absolute in a reaction space constructed as a meandering tube system in which the hydrogenation is carried out in a loop reactor made of tubes of the same nominal diameter and arranged either vertically or horizontally and connected by curving tubes (tube elbows) at flow velocities in the tubes of more than 3 m/sec.

Continuous process for the production of hydrogen peroxide according to

Tetra substituted ureas wherein at least one substituent is an aryl group have proven very oxidation resistant in the anthraquinone process for making hydrogen peroxide. The urea nitrogen is directly attached to the aryl group. These ureas can be used as a single solvent or as a component of a mixture of solvents.

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Kleinostheim, Germany

Wolfgang Kunkel