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A method for preparing high-purity isobutene from tert-butanol produced by the co-oxidation method to produce propylene oxide by-product

A technology of propylene oxide and co-oxidation method, which is applied in the preparation of organic compounds, chemical instruments and methods, preparation of hydroxyl compounds, etc., can solve problems such as incomplete treatment of organic acid esters, equipment corrosion, catalyst poisoning and deactivation, etc., to achieve Improve efficiency and economy, lower production cost, and simplify processing

Active Publication Date: 2015-12-30
WANHUA CHEM GRP CO LTD +1
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Problems solved by technology

However, the co-oxidation process is complicated, and the by-product tert-butanol contains organic acid esters. In the process of cracking isobutene in an acidic environment, organic acid esters decompose to produce organic acids, especially formic acid produced by the decomposition of formate esters, which severely corrodes equipment; At the same time, metal ions produced by corrosion can easily lead to catalyst poisoning and deactivation
[0005] Most of the existing technologies use hydrogenation to remove esters, which needs to introduce new material hydrogen into the system, and use expensive Pd-based hydrogenation catalysts, organic acid esters are not completely treated, and the conversion rate of general esters is 80-90%. The content of the organic acid ester in the by-product TBA obtained after separation and purification is 10-20% of that before treatment. Using this material to prepare IB by dehydration can only alleviate the derivation hazards of the organic acid ester to the equipment and the catalyst, but cannot completely eradication, while the introduction of a hydrogenation process increases operational complexity
The removal of organic acid esters can also be saponified and decomposed by strong bases in an alkaline environment with pH>9 to generate corresponding alcohols and organic acid salts. However, the introduction of strong bases increases the content of metal ions in the system. For tert-butanol Dehydration resin catalyst has a great poisoning effect

Method used

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  • A method for preparing high-purity isobutene from tert-butanol produced by the co-oxidation method to produce propylene oxide by-product

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Experimental program
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Effect test

Embodiment 1

[0030] The purity of the tert-butanol by-product of co-oxidation of propylene oxide is 96.24wt%, and the content of formate is 1.05wt% (wherein isobutyl formate is 0.60wt%, isopropyl formate is 0.35wt%, and methyl formate is 0.10wt%. %), acetate content is 0.52wt% (of which isobutyl acetate 0.24wt%, isopropyl acetate 0.15wt%, methyl acetate 0.13wt%), methanol 0.51wt%, acetone 1.03wt%, water 0.65wt %. The tert-butanol containing the above organic acid ester impurities at 50℃, 0.2MPa, 1h -1 Under the conditions, flow through the catalyst PS-NH 2 The two fixed-bed reactors in series, the reactor outlet detection and analysis did not find organic acid esters, formic acid, and acetic acid. The pH value of the by-product tert-butanol after treatment was 7.0. Under the conditions of reflux ratio 1, processing capacity 0.75Kg / (Kg catalyst·h), sulfonic acid resin Rohm and Haas 35 is used as catalyst for catalytic distillation and dehydration. The catalytic distillation tower is filled w...

Embodiment 2

[0032] The purity of tert-butanol by-product of co-oxidation of propylene oxide is 90.88wt%, and the total content of formate is 3.2wt% (of which isobutyl formate is 1.50wt%, isopropyl formate is 0.97wt%, and methyl formate is 0.73wt%) , Methanol 0.47wt%, acetone 1.53wt%, water 3.92wt%. The tert-butanol containing the above organic acid ester impurities at 70℃, 0.1MPa, 2h -1 Under the conditions, flow through PS-NHCH filled with catalyst 2 CH(CH 3 ) 2 Two fixed-bed reactors in parallel, the reactor outlet detection and analysis found that isobutyl formate 0.01wt%, other organic acid esters, formic acid, and acetic acid were not detected. The pH of the by-product tert-butanol after treatment was 7.0. Under the conditions of 0.12MPa, reflux ratio of 1.5, and processing capacity of 0.5Kg / (Kg catalyst·h), the by-product tert-butanol is catalytically rectified and dehydrated with sulfonic acid resin as the catalyst. The catalytic distillation tower is filled with sulfonic acid resin....

Embodiment 3

[0034] The purity of tert-butanol by-product of co-oxidation of propylene oxide is 96.32wt%, and the total content of formate is 0.52wt% (of which isobutyl formate 0.21wt%, isopropyl formate 0.10wt%, methyl formate 0.05wt%) , The acetate content is 0.08wt% (wherein isobutyl acetate 0.03wt%, isopropyl acetate 0.02wt%, methyl acetate 0.03wt%), methanol 0.42wt%, acetone 0.97wt%, water 1.69wt%. Tert-butanol containing the above organic acid ester impurities at 60℃, 0.3MPa, 0.5h -1 Under the conditions, flow through PS-NHCH filled with catalyst 3 Two fixed-bed reactors connected in series. The outlet of the reactor revealed that isobutyl formate was 0.02% by weight and isopropyl formate was 0.01% by weight. The pH of the by-product tert-butanol after treatment was 7.0. Butanol is catalytically rectified and dehydrated under the conditions of 0.3MPa, reflux ratio 0.5, processing capacity 0.98Kg / (Kg catalyst·h) with sulfonic acid resin Rohm and Haas 15 as the catalyst, and the catalyti...

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Abstract

The invention relates to a method for preparing high-purity isobutene by using a byproduct tertiary butanol obtained in production of epoxypropane with a cooxidation method. The method comprises the following steps: under the effect of a basic resin catalyst, decomposing organic acid ester in tertiary butanol into organic acid, and adsorbing organic acid; cracking tertiary butanol without organic acid ester impurities in a catalytic rectifying tower; and refining to obtain the high-purity isobutene with the purity being below 99.95wt%. The method solves the problem that organic acid ester impurities in direct cracking of byproduct tertiary butanol of epoxypropane are decomposed in the catalytic rectifying tower, effectively prevents equipment materials from being corroded by the organic acid generated by hydrolysis of the organic acid ester, and prolongs the service life of the cracking catalyst, so that an isobutene product is stable, free from an isobutene isomer and low in production cost.

Description

Technical field [0001] The invention relates to a method for preparing high-purity isobutene by using co-oxidation method propylene oxide by-product tert-butanol to prepare high-purity isobutylene, and specifically relates to a method for removing organic acid ester impurities in co-oxidation method propylene oxide by-product tert-butanol and then cracking to prepare high purity isobutylene. Pure isobutylene method. Background technique [0002] Isobutylene (IB), especially high-purity IB, has a wide range of downstream applications, involving many fields such as organic chemicals, synthetic resins, and synthetic rubbers. At present, the production methods of high-purity isobutene are mainly MTBE cracking, butane dehydrogenation, and tert-butanol dehydration, among which tert-butanol dehydration is the most economical method. [0003] The raw material of the existing tert-butanol dehydration process mainly comes from the tert-butanol aqueous solution prepared by C4 hydration, the ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C1/24C07C11/09C07C29/88C07C31/12
CPCY02P20/10
Inventor 王中华何岩董如伟袁帅孙安乐吕艳红刘军林建平于学丽王文杨长巧杨险峰张俊平成兆坤
Owner WANHUA CHEM GRP CO LTD