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Modification method of silicon molecular sieve and preparation method of caprolactam

A silicon molecular sieve and caprolactam technology, applied in the field of caprolactam preparation, can solve problems such as short lifespan, and achieve the effects of increasing operating life, improving selectivity and lifespan, and increasing external specific surface area.

Pending Publication Date: 2022-05-13
JIANGSU YANGNONG CHEM GROUP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] The main purpose of the present invention is to provide a modification method of silicon molecular sieve and a preparation method of caprolactam, to solve the problem of short lifetime of gas-phase Beckmann rearrangement catalysts in the prior art

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  • Modification method of silicon molecular sieve and preparation method of caprolactam
  • Modification method of silicon molecular sieve and preparation method of caprolactam
  • Modification method of silicon molecular sieve and preparation method of caprolactam

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preparation example Construction

[0028] In another typical embodiment of the present application, a preparation method of caprolactam is provided, the preparation method comprising: Step A, gasifying cyclohexanone oxime to obtain a gasified product; Step B, using a catalyst to catalyze the gas The chemical compound is subjected to a gas-phase Beckmann rearrangement reaction to obtain a product system containing caprolactam, and the catalyst is a modified silicon molecular sieve obtained by any of the above-mentioned modification methods; Step C is to purify the caprolactam in the product system to obtain caprolactam.

[0029]The caprolactam selectivity and cyclohexanone oxime conversion rate of the modified silicon molecular sieve modified by the modification method of the present application are maintained at a high level, and the service life of the catalyst is significantly prolonged, which improves the production efficiency of caprolactam.

[0030] The gasification process of cyclohexanone oxime, the gas p...

Embodiment 1

[0034] 30g of all-silicon molecular sieve powder Silicalite-1 (average pore diameter 14.3nm, pore volume 0.8cm 3 / g, the specific surface area is 350m 2 / g) into a tube furnace, at 310°C for 0.5h -1 A mixture of ammonia, water vapor and nitrogen is introduced at a volumetric space velocity, wherein the volume ratio of ammonia: water vapor: nitrogen is 1:0.5:2, and the reaction takes 10 hours. Then, pass through to 2h -1 The volume space velocity is passed through nitrogen for 30min, and then switched to 0.5h at 500°C -1 The modified all-silicon molecular sieve was obtained by roasting in air for 10 hours.

Embodiment 2-5

[0036] On the basis of Example 1, silicon molecular sieves were changed, and the original powder Silicalite-1 (average pore diameter 0.1nm, pore volume 0.1cm) was crystallized with all-silicon molecular sieves respectively. 3 / g, the specific surface area is 272m 2 / g), spherical all-silicon molecular sieve Silicalite-1 (average pore diameter 27.5nm, pore volume 0.9cm 3 / g, the specific surface area is 375m 2 / g, ball diameter 0.2mm), cylindrical molecular sieve Silicalite-1 (average pore diameter 49.7nm, pore volume 4.8cm 3 / g, the specific surface area is 402m 2 / g, diameter 1.6mm, length 1.5mm) and circular Silicalite-1 (average pore diameter 36.3nm, pore volume 2.4cm 3 / g, the specific surface area is 251m 2 / g, internal diameter 1.1mm, external diameter 2.3mm, long 2.0mm) replace the former powder of all-silicon molecular sieve, modification method is the same as embodiment 1.

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Abstract

The invention provides a modification method of a silicon molecular sieve and a preparation method of caprolactam. The modification method comprises the following steps: S1, at 200-400 DEG C, carrying out modification treatment on a silicon molecular sieve by using alkaline vapor to obtain a primarily modified silicon molecular sieve, the alkaline vapor comprising alkali, water vapor and a first carrier gas; and S2, roasting the primarily modified silicon molecular sieve in oxidizing gas at 400-600 DEG C to obtain the modified silicon molecular sieve. The silicon molecular sieve is subjected to high-temperature gas-phase alkali modification by using alkaline steam, so that the external specific surface area is increased, especially the pore size is increased, and the strong acid site B on the surface is reduced; and then roasting to remove alkali left on the surface of the catalyst and in pores, and dehydrating silicon hydroxyl generated by water vapor treatment, so that the surface of the catalyst keeps proper acidity and polarity. When the catalyst is applied to preparation of caprolactam through gas-phase Beckmann reaction, high conversion rate of cyclohexanone-oxime and high selectivity of caprolactam are realized, and the service life is remarkably prolonged.

Description

technical field [0001] The invention relates to the technical field of caprolactam preparation, in particular to a method for modifying silicon molecular sieves and a method for preparing caprolactam. Background technique [0002] Caprolactam is an important intermediate in the industrial production of nylon, and the Beckmann rearrangement of cyclohexanone oxime is one of the key steps in the production process of caprolactam. At present, the traditional liquid-phase rearrangement process using concentrated sulfuric acid as a catalyst is mainly used in industry. Although the reaction conditions of this process are relatively mild, and the conversion rate and selectivity are relatively ideal, a large amount of ammonium sulfate is produced as a by-product, and it is easy to cause equipment corrosion and environmental pollution. In order to overcome the above shortcomings, the use of solid acids such as molecular sieves to catalyze cyclohexanone oxime gas-phase Beckmann rearra...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B01J29/70B01J35/08B01J35/10C07D201/04C07D201/16
CPCB01J29/70C07D201/04C07D201/16B01J2229/16B01J35/51B01J35/633B01J35/635B01J35/638B01J35/643B01J35/647B01J35/615
Inventor 王刚郭昊天王根林丁克鸿徐林汪洋许越戴业涔韩敏
Owner JIANGSU YANGNONG CHEM GROUP
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