A kind of preparation method and application of thin-layer nano-sheet all-silicon molecular sieve for preparing caprolactam

An all-silicon molecular sieve and nano-sheet technology, applied in the directions of silicon oxide and silicon dioxide, can solve the problems of complex process, low conversion rate, catalyst deactivation, etc., to reduce environmental pollution, improve catalytic activity, and reduce coking loss. live effect

Active Publication Date: 2016-04-06
TAIYUAN UNIV OF TECH +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] CN102658191B discloses a supported solid acid catalyst with heteropolyacid as the active component and mesoporous molecular sieve as the carrier for the Beckmann rearrangement reaction of cyclohexanone oxime, but its conversion rate is only 82.5%, and the selectivity is only 87.1% %
CN103288735A has reported a mixed catalytic system with acidic ionic liquid and ZSM-5, the reaction conditions are relatively mild, but the catalyst deactivation is very fast
CN102895996A discloses a homogeneous catalytic system composed of organic acid and organic solvent, but the product is not easy to separate
[0011] In ACSCatal.2011,1:337, Ryoo et al reported the use of asymmetric double-headed ammonium surfactant [C 16 h 33 -N + (CH 3 ) 2 -C 6 h 12 -N + (CH 3 ) 2 -C 6 h 13 ](OH) - 2 A single-layer sheet-like hierarchical porous all-silicon molecular sieve with a b-axis thickness of 2nm was synthesized for gas-phase Beckmann rearrangement reaction, WHSV=3h -1 , the reaction temperature is 350°C, the initial conversion rate is 85%, and it drops to 65% after 100 hours. The activity and stability of the catalyst are much higher than that of large particle all-silicon molecular sieves, but compared with the existing industrial application level, the conversion rate is low In addition, adopting the higher toluene and acetonitrile of toxicity and cost as solvent synthesis template is unfavorable for industrialized large-scale production: the harm of toluene to human health includes irritation to skin and mucous membranes, and anesthesia to central nervous system
Acetonitrile is extremely volatile and is a moderately toxic substance that is extremely harmful to the human body, and the discharge of waste liquid can cause serious environmental pollution; using anion exchange resin to exchange bromine-type template agent to obtain hydrogen-oxygen-type template agent, the process is complicated and the cost is high
Currently disclosed patents and documents do not use the very low toxicity of green chemicals dimethyl carbonate, diethyl carbonate and ethanol, propanol as a solvent to synthesize bromine-type, chlorine-type asymmetric double-headed ammonium surfactants, and directly use Synthesis of thin-layer nanosheet silicalite-1 molecular sieves with bromine-type and chlorine-type templates

Method used

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  • A kind of preparation method and application of thin-layer nano-sheet all-silicon molecular sieve for preparing caprolactam
  • A kind of preparation method and application of thin-layer nano-sheet all-silicon molecular sieve for preparing caprolactam
  • A kind of preparation method and application of thin-layer nano-sheet all-silicon molecular sieve for preparing caprolactam

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0042] a. Add 51.6g of tetramethylhexamethylenediamine, 337ml of dimethyl carbonate, and 33.3g of bromooctadecane into a flat-bottomed flask, heat under reflux in a water bath at 50°C for 8 hours under stirring, cool to room temperature, and filter. Wash with dimethyl carbonate for 1-2 times, and air-dry to make the intermediate; add 50.5g of the intermediate, 300ml of ethanol, and 49.5g of bromohexane into a flat-bottomed flask, and heat under reflux in an oil bath at 79°C for 10 hours while stirring . After completion, heat up to 85°C, stir and dry to obtain a light yellow translucent solid, cool to room temperature, wash with ether 1-2 times, and obtain template C 18-6-6 Br 2 , the yield is 99%.

[0043] b. Add 4.98g of ethyl orthosilicate to 3.83g of tetramethylammonium hydroxide, stir at room temperature for 10 minutes, then add 17g of deionized water, 2.5g of ethanol, and 0.85g of the template agent C prepared in step a above 18-6-6 Br 2 , after stirring evenly, heat...

Embodiment 2

[0047] a. Add 86g of tetramethylhexamethylenediamine, 500ml of diethyl carbonate, and 39g of bromobehenic acid into a flat-bottomed flask, heat it under reflux in a water bath at 55°C for 5 hours under stirring, cool to room temperature, centrifuge, and Wash with diethyl carbonate for 1-2 times, and air-dry to make an intermediate; add 56.1g of the intermediate, 300ml of ethanol, and 33g of bromohexane into a flat-bottomed flask, and heat under reflux in an oil bath at 79°C for 10 hours while stirring. After completion, heat up to 85°C, stir and dry to obtain a yellow translucent solid, cool to room temperature, wash with ether 1-2 times, and obtain template C 22-6-6 Br 2 , the yield is 99.2%.

[0048] b. Add 4.98g of ethyl orthosilicate to 1.28g of tetramethylammonium hydroxide, stir at room temperature for 15 minutes, then add 14.40g of deionized water, 2.5g of ethanol, and 0.78g of the template prepared in step a above C 18-6-6 Br 2 After stirring evenly, heat in a wate...

Embodiment 3

[0051] a. Add 51.6g of tetramethylhexamethylenediamine, 350ml of dimethyl carbonate, and 24.9g of dodecane bromide into a flat-bottomed flask, heat under reflux in a water bath at 45°C for 10 hours under stirring, cool to room temperature, and centrifuge. Wash with dimethyl carbonate for 1-2 times, and air-dry to make the intermediate; add 42.1g of the intermediate, 300ml of propanol, and 20.55g of bromobutane into a flat-bottomed flask respectively, and heat under reflux in an oil bath at 85°C for 8 Hour. After completion, heat up to 90°C, stir and dry, cool to room temperature, and wash with ether 1-2 times to obtain template C 12-6-4 Br 2 , the yield is 99.3%.

[0052] b. Add 4.98g of tetraethylammonium hydroxide to 1.28g of tetraethylammonium hydroxide, stir at room temperature for 8 minutes, then add 18.90g of deionized water, 2.5g of ethanol, and 0.69g of the template prepared in step a above C 12-6-4 Br 2 After stirring evenly, heat in a water bath at 63°C for 1.5 ...

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Abstract

The invention relates to a preparation method of a thin-layer nano flaky total-silicon molecular sieve for preparing caprolactam. The preparation method comprises the following steps: uniformly stirring a silicon source and an alkali source to obtain a mixture I; dissolving a template agent in a mixed solution of deionized water and ethanol to obtain a mixture II, and gradually dropwise adding the mixture I into the mixture II to be stirred to obtain a mixture III, and stirring the mixture III in a water bath to obtain initial gel; dynamically crystallizing the initial gel in a closed reaction kettle, and washing and drying the initial gel to obtain the thin-layer nano flaky total-silicon molecular sieve. The preparation method has the advantages of low cost, small energy consumption, high conversion rate, no pollution and capability of realizing industrial production.

Description

technical field [0001] The invention belongs to the preparation of molecular sieves, and in particular relates to a preparation method and application of a thin-layer nano-flaky all-silicon Silicalite-1 molecular sieve prepared from caprolactam. Background technique [0002] Caprolactam is an important intermediate used in the synthesis of nylon-6 fibers and resins, and is widely used in artificial leather, medicine, and chemical additives. In 2010, the domestic self-sufficiency rate of caprolactam was 43.9%, and the amount of imported caprolactam in my country increased by an average of 12% per year. The domestic production capacity is insufficient, and a large number of imports are relied on. [0003] At present, caprolactam is mainly synthesized by Beckmann rearrangement reaction of cyclohexanone oxime. There are two main processes to realize this process: liquid-phase Beckmann rearrangement and gas-phase Beckmann rearrangement. Since the liquid-phase Beckmann rearrangem...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01B33/12
Inventor 李晓峰葛超刘晓臻窦涛
Owner TAIYUAN UNIV OF TECH
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