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Method for synthesizing caprolactam

A technology of caprolactam and cyclohexanone oxime, which is applied in the synthesis field of caprolactam, can solve the problems of consuming high-value sulfuric acid, equipment corrosive environment, unsolved sulfuric acid, etc., and achieves the effects of long reaction time and short regeneration time

Inactive Publication Date: 2003-05-07
CHINA PETROLEUM & CHEM CORP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

The process has mild reaction conditions, high conversion rate of cyclohexanone oxime, and good selectivity of caprolactam, but the disadvantage is that it consumes high-value sulfuric acid and ammonia, and produces cheap ammonium sulfate by-product. At the same time, the use of sulfuric acid also causes problems such as equipment corrosion and environmental pollution.
Although since the 1980s, in order to reduce the output of by-products, people have adopted methods such as multi-stage rearrangement reactor series process and strict control of water content in cyclohexanone oxime to reduce the amount of by-product ammonium sulfate, but the use of sulfuric acid The problems caused have not been solved, which is unsatisfactory in today's advocacy of atomic economy and environmental protection economy
[0008] The gas-phase Beckmann rearrangement reaction of cyclohexanone oxime can be continuously completed in the form of fluidized bed reaction to produce caprolactam, but there are problems of high investment cost and frequent catalyst regeneration affecting selectivity.

Method used

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  • Method for synthesizing caprolactam
  • Method for synthesizing caprolactam
  • Method for synthesizing caprolactam

Examples

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Effect test

example 1

[0037] Pour 208 grams of tetrapropylammonium hydroxide (abbreviated as TEOS) into a 1000 ml beaker at room temperature, stir for 30 minutes, add 180 grams of 22.5% tetrapropylammonium hydroxide (abbreviated as TPAOH) solution In ethyl acetate, stir and hydrolyze at room temperature for 2 to 3 hours, heat up to 70 to 75°C, stir for 3 to 5 hours, add 220 grams of water to form a sol, stir evenly, and the molar concentration is TPAOH / SiO 2 =0.2,H 2 O / SiO 2 =20, the above mixture was moved into a 500 ml polytetrafluoroethylene-lined stainless steel reactor, crystallized at 170°C for 2 days, filtered, washed, dried at 120°C for 24 hours, and calcined at 550°C for 5 hours.

[0038] Mix the roasted product with 55 grams of 22.5% TPAOH aqueous solution evenly, crystallize in a sealed reactor at 150°C for 1 day, filter, wash, dry at 110°C for 12 hours, and roast at 550°C for 4 hours to obtain a silicon molecular sieve product, No. a. Its BET specific surface area is 464 meters 2 / g...

example 2

[0040] Pour 208 grams of tetrapropylammonium hydroxide into a 500 ml beaker at room temperature, stir for 30 minutes, add 180 grams of 22.5% tetrapropylammonium hydroxide aqueous solution into TEOS, stir and hydrolyze for 2 hours at room temperature, add 220 grams of water, and add ethanol (abbreviated as EtOH) 184 grams, stirred evenly to be a sol, the chemical composition of the mixed clear liquid was H 2 O / SiO 2 =20, EtOH / SiO 2 =8,TPAOH / SiO 2 =0.20, crystallized at 110°C for 2 days, filtered, washed, dried at 120°C for 24 hours, and calcined at 550°C for 5 hours.

[0041] Mix the roasted product with 55 grams of 22.5% TPAOH aqueous solution evenly, crystallize in a sealed reaction kettle at 150°C for 1 day, filter, wash, dry at 110°C for 12 hours, and roast at 550°C for 4 hours to obtain a silicon molecular sieve product, code B . Its BET specific surface area is 481 meters 2 / g, the outer specific surface is 70 meters 2 / g, the X-ray diffraction pattern of the produc...

example 3

[0043] Pour 208 g of tetrapropylammonium hydroxide into a 500 ml beaker at room temperature, stir for 30 minutes, add 22.5% tetrapropylammonium hydroxide aqueous solution, stir and hydrolyze for 2 hours at room temperature, add water and ethanol, stir well, and make the mixture clear The chemical composition of the liquid is H 2 O / SiO 2 =20, EtOH / SiO 2 =16,TPAOH / SiO 2 =0.20, crystallized at 110°C for 2 days, filtered, washed, dried at 120°C for 24 hours, and calcined at 550°C for 5 hours.

[0044] Mix the roasted product with 67.8 grams of 22.5% TPAOH aqueous solution evenly, crystallize in a sealed reactor at 110°C for 4 days, filter, wash, dry at 110°C for 12 hours, and roast at 550°C for 4 hours to obtain a silicon molecular sieve product, code C . Its BET specific surface area is 488 meters 2 / g, the outer specific surface is 75 meters 2 / g, from the X-ray diffraction pattern of the product has figure 1 characteristics; the adsorption-desorption spectrum of low-temp...

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Abstract

A process for preparing caprolactam features that said caprolactam is synthesized from cyclohexanone oxime in fixed-bed reaction system, where the silicon molecular sieve with MFI structure and concave-convex surface for high specific surface area is used as its catalyst. Its advantages are high conversion rate of cyclodexanone oxide (99.5%) and high selectivity to caprolactam (96%).

Description

technical field [0001] The invention relates to a synthesis method of caprolactam, more specifically to a method for synthesizing caprolactam from cyclohexanone oxime in a fixed-bed reaction system using silicon molecular sieve as a catalyst. Background technique [0002] Caprolactam is the main raw material for the production of three series of products: nylon, industrial cord and nylon engineering plastics. Sulfuric acid catalyzed liquid-phase Beckmann rearrangement process is generally used in industry. This process is to make cyclohexanone oxime in concentrated sulfuric acid or oleum Under the action of catalysis, a Beckmann rearrangement reaction occurs at 80-100°C, and then ammonia is used to neutralize the acidity of the reaction system, and the by-products of caprolactam and ammonium sulfate are generated. The process has mild reaction conditions, high conversion rate of cyclohexanone oxime, and good caprolactam selectivity, but the disadvantage is that it consumes h...

Claims

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Application Information

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IPC IPC(8): C07D201/04C07D223/10
CPCY02P20/52
Inventor 程时标汪顺祖吴巍
Owner CHINA PETROLEUM & CHEM CORP
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