Method for producing hydrogen peroxide

A technology of hydrogen peroxide and hydrogen, applied in chemical instruments and methods, peroxide/peroxyhydrate/peroxyacid/superoxide/ozonide, inorganic chemistry, etc., can solve problems such as catalyst wear, and achieve The effect of preventing clogging

Inactive Publication Date: 2017-02-22
EVONIK DEGUSSA GMBH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, as known from WO 98/16463, high fl...

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] Embodiment 1 (not the present invention)

[0027] The reaction was carried out in a bubble column reactor having an internal diameter of 16 mm and a length of 200 cm and containing a cooling jacket. A fixed bed of catalyst with a bed volume of about 400 ml was placed in the reactor between two screens so that it could not expand. The catalyst used was a supported palladium catalyst comprising 0.1 mass % palladium on alumina in spherical form with a median diameter of 2 mm.

[0028] A liquid reaction medium consisting of 98 parts by weight of methanol and 2 parts by weight of water containing 0.0001 mol / l of sodium bromide and 0.01 mol / l of sodium bromide was supplied to it from below the reactor at a rate of 2 l / h of sulfuric acid. Simultaneously 1Nm 3 A gas mixture consisting of 3% by volume of hydrogen, 20% by volume of oxygen and 77% by volume of nitrogen was introduced from the bottom of the reactor. During the reaction, the pressure of the reactor was maintaine...

Embodiment 2

[0030] Embodiment 2 (not the present invention)

[0031] Example 1 was repeated except that the intersieve space was only filled to 80% capacity with catalyst instead of being completely filled. It provides the catalyst with an additional volume of 20% based on its static volume for expansion under reaction conditions.

[0032] After the reactor has been running for 24 hours, the hydrogen conversion rate is 20% and the hydrogen peroxide solution taken out has a hydrogen peroxide content of 1.6% by weight. The selectivity to hydrogen peroxide in the reaction was 73%, based on the hydrogen gas reacted. The pressure drop across the fixed bed of catalyst was 210 mbar. After 127 h of operation the pressure drop increased to over 10 bar within a few minutes and the reactor had to be shut down.

Embodiment 3

[0033] Embodiment 3 (the present invention)

[0034] Example 2 was repeated, except instead of the upper sieve, a layer of about 12 ml of PTFE wool (Semadeni PTFE sealing wool) covered with 20 ml of Raschig ring packing (3×3 mm glass AR Raschig ring from Gebrüder Rettberg GmbH) was deposited on Catalyst fixed bed. The Raschig rings form a rigid reaction packing that is immovable under the reaction conditions, and thus the catalyst fixed bed expands by only about 3% of its volume during the reaction by compressing the PTFE fleece.

[0035] After 24 hours of operation of the reactor, the hydrogen conversion rate was 22%, and the hydrogen peroxide solution taken out had a hydrogen peroxide content of 1.8% by weight. The selectivity to hydrogen peroxide in the reaction was 72%, based on the hydrogen gas reacted. The pressure drop across the fixed bed of catalyst was 215 mbar. After running for 3000h, the pressure drop remained stable at 215mbar. The hydrogen conversion was 21%...

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Abstract

The invention relates to a method for producing hydrogen peroxide by converting hydrogen and oxygen in the presence of a liquid reaction medium and a particulate noble metal support catalyst in a fixed-bed reactor, wherein the liquid reaction medium and a gas phase containing hydrogen and oxygen flow against the fixed bed from below. The fixed bed is arranged in the reactor such that the volume of the fixed bed expands by 1 to 10% in the operating state relative to a rest state without a flow against the fixed bed. As a result of the fixed bed expansion according to the invention, the fixed bed can be prevented from clogging due to abrasions on the catalyst.

Description

technical field [0001] The invention relates to a method for preparing hydrogen peroxide by reacting hydrogen and oxygen in a fixed-bed reactor in the presence of a supported noble metal catalyst. Background technique [0002] It is well known to utilize the direct synthesis of a gas mixture comprising hydrogen and oxygen to prepare hydrogen peroxide by reacting the gas mixture over a noble metal catalyst in the presence of an aqueous, aqueous-organic or organic reaction medium. Hydrogen peroxide solutions available from direct synthetic methods are of interest as oxidizing agents for the catalytic oxidation of organic compounds. Direct synthesis methods can use noble metal catalysts in fixed beds as suspended catalysts or as supported noble metal catalysts. [0003] An advantage of the reaction in a fixed bed is that no separation of the reaction product from the catalyst is required. The reaction can be carried out in the reactor as a bubble column, in which in the opera...

Claims

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Application Information

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IPC IPC(8): C01B15/029B01J8/02
CPCC01B15/029B01J8/025B01J8/0278B01J8/0285B01J8/0292B01J8/0453B01J8/0492B01J8/0496B01J8/067B01J2208/0015B01J2208/00212B01J2208/00884B01J2208/00938B01J8/0242B01J2219/00761
Inventor T·哈斯
Owner EVONIK DEGUSSA GMBH
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