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Method for producing methacrylic acid

A methacrylic acid, regional technology, applied in the directions of organic chemistry methods, chemical instruments and methods, carboxylate preparation, etc., can solve the problems such as the inability to improve the yield of methacrylic acid and the limitation of reaction conditions.

Inactive Publication Date: 2003-04-09
MITSUBISHI CHEM CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Therefore, the reaction conditions need to be more limited
That is to say, currently in industry, the concentration of methacrolein can be increased to a certain extent, but the yield of the corresponding concentration of methacrylic acid cannot be increased.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] 100 parts of ammonium paramolybdate, 2.8 parts of ammonium metavanadate and 9.2 parts of cesium nitrate were dissolved in 300 parts of water. In addition, a solution obtained by dissolving 8.2 parts of 85% by mass phosphoric acid in 10 parts of water and a solution obtained by dissolving 1.1 parts of telluric acid in 10 parts of water were added to the above solution while stirring, and the temperature was raised to 95° C. under stirring. Then, a solution obtained by dissolving 3.4 parts of copper nitrate, 7.6 parts of iron nitrate, 1.4 parts of zinc nitrate and 1.8 parts of magnesium nitrate in 80 parts of pure water was added thereto. The mixture was further stirred at 100°C for 15 minutes, and the resulting slurry was dried with a spray drier.

[0035] Add 2 parts graphite to the above 100 parts dried and mix well. The mixture is then compressed into ring-shaped tablets with an outer diameter of 5 mm, an inner diameter of 2 mm, and a length of 3 mm with a tablet pre...

Embodiment 2

[0052] 100 parts of molybdenum trioxide, 3.2 parts of vanadium pentoxide and 6.7 parts of 85% by mass phosphoric acid were mixed with 800 parts of pure water. After stirring the mixture under reflux for 3 hours, 0.5 parts of copper oxide, 0.7 parts of boric acid and 1.2 parts of germanium dioxide were added thereto, and the mixture was stirred under reflux for 2 hours. The obtained slurry was cooled to 50° C., a solution obtained by dissolving 11.2 parts of cesium bicarbonate in 30 parts of pure water was added thereto, and stirred for 15 minutes. Then, a solution obtained by dissolving 10 parts of ammonium nitrate in 30 parts of pure water was added to the slurry, and stirred for another 15 minutes. The obtained slurry containing the catalyst component was dried with a spray drier.

[0053] Add 2 parts graphite to the above 100 parts dried and mix well. The mixture is then compressed into ring-shaped tablets with an outer diameter of 5 mm, an inner diameter of 2 mm, and a l...

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Abstract

A method for producing methacrylic acid by means of a fixed bed tubular reactor having a catalyst layer filled with a solid oxidation catalyst and a heating medium bath by passing a raw material gas containing methacrolein and oxygen through the catalyst layer, characterized in that the catalyst layer has no areas exhibiting a difference in temperature ( DELTA T) from that of the heating medium bath of 35 DEG C and has two or more high temperature areas exhibiting a DELTA T of 15 to 35 DEG C. The method can be used for producing methacrylic acid in a higher yield.

Description

technical field [0001] The invention relates to a method for producing methacrylic acid by using a fixed-bed tubular reactor and carrying out gas-phase catalytic oxidation of methacrolein with molecular oxygen in the presence of a solid-state oxidation catalyst. Background technique [0002] There have been many studies on catalysts for the production of methacrylic acid by gas-phase catalytic oxidation of methacrolein. (The gas-phase catalytic oxidation reaction here, unless otherwise specified, just refers to the "oxidation reaction".) These studies mainly involve the elemental composition and ratio of the catalyst. [0003] Since this is an exothermic reaction, the oxidation process will cause a buildup of heat on the catalyst bed. Localized areas of abnormally high temperature caused by excess heat buildup are called "hot spots". At hotspots, excessive oxidation reactions will result in reduced reaction yields. Therefore, the generation of hot spots is a serious probl...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/25C07C57/055
CPCC07C51/252C07C57/04C07C51/235
Inventor 渡边聖午大北求
Owner MITSUBISHI CHEM CORP