Method for synthesis of 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanedione

A technology of cyclobutanedione and tetramethyl, applied in the field of organic compound preparation, can solve the problems of high cost, difficult to improve the conversion rate of cracking reaction, and many equipments, and achieves the effect of reducing equipment investment, avoiding large consumption and energy loss

Inactive Publication Date: 2016-07-06
PETROCHINA CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0012] The technical scheme of the present invention is in order to overcome the inadequacies of the prior art that the cracking reaction conversion rate is difficult to

Method used

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  • Method for synthesis of 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanedione

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0041] 100g of isobutyric acid is fed through a feed pump at a feed rate of 4ml / min, and nitrogen is fed at a feed rate of 20ml / min. After the two are mixed in a mixer, they pass through the cracking reaction device. The cracking temperature is 440°C. The pressure of the reaction process is 3KPa. After the reaction, the reaction product passes through the condenser quickly, and the cooling temperature is controlled at 10°C. The cooled gas-liquid mixture is separated through the separation tank. A 1:1 mixture of dimethyl ester and dimethyl 1,4-cyclohexanedicarboxylate was polymerized at a temperature of 90°C for 60 minutes. 2,2,4,4-Tetramethyl-1,3-cyclobutanedione at a content of 5% (WT) relative to the solvent was obtained by gas chromatography analysis of the absorption liquid.

[0042] The reaction results are as follows:

[0043] Feed rateml / min

Embodiment 2

[0045] 120g of isobutyric anhydride is fed through a feed pump at a feed rate of 6ml / min, nitrogen is fed at a feed rate of 48ml / min, and the two are mixed in a mixer and then passed through the cracking reaction device. The cracking temperature is 480°C. The pressure of the reaction process is 30KPa. The reacted reaction product passes through the condenser quickly, and the cooling temperature is controlled at 20°C. The cooled gas-liquid mixture is separated through the separation tank, and the gas phase product enters the polymerization kettle for reaction first. A 1:2 mixture of dimethyl adipate and dimethyl 1,4-cyclohexanedicarboxylate has been added to the polymerization kettle, and the temperature is controlled at 120°C for 80 minutes of polymerization. By gas chromatography analysis of the absorption solution, 2,2,4,4-tetramethyl-1,3-cyclobutanedione with a content of 15% (WT) relative to the solvent was obtained.

[0046] The reaction results are as follows:

[0047] ...

Embodiment 3

[0049] 200g of isobutyric anhydride is fed through a feed pump at a feed rate of 8ml / min, and nitrogen is fed at a feed rate of 80ml / min. After the two are mixed in a mixer, they pass through the cracking reaction device. The cracking temperature is 520°C. The pressure of the reaction process is 50KPa, the reaction product after the reaction quickly passes through the condenser, the cooling temperature is controlled at 15°C, the cooled gas-liquid mixture is separated through the separation tank, and dimethyl adipate and 1,4 A 1:3 mixed solution of dimethyl cyclohexanedicarboxylate was polymerized at a controlled temperature of 120°C for 80 minutes. By gas chromatography analysis of the absorption solution, 2,2,4,4-tetramethyl-1,3-cyclobutanedione with a content of 15% (WT) relative to the solvent was obtained.

[0050] The reaction results are as follows:

[0051] Feed rateml / min

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Abstract

The invention belongs to the technical field of organic compound preparation, and is a preparation method for 2,2,4,4-tetramethyl-1,3-cyclobutanedione, which comprises isobutyric acid or isobutyric anhydride and Under the condition that the volume ratio of the inert gas is 1/10 to 1/5, the cracking reaction is carried out through a fixed bed cracking reactor to obtain dimethyl ketene; Direct polymerization in solution to obtain 2,2,4,4-tetramethyl-1,3-cyclobutanedione. Advantages of the present invention: the preparation process of 2,2,4,4-tetramethyl-1,3-cyclobutanedione is optimized, that is, the product after cracking is directly polymerized, equipment investment is reduced, and washing tower or absorption The tower avoids a large amount of absorption liquid consumption and energy loss; the above-mentioned features make the inventive technology more flexible than the methods currently used in industrial production, and compared with other competitive processes.

Description

technical field [0001] The invention belongs to the technical field of organic compound preparation, and relates to a method for synthesizing 2,2,4,4-tetramethyl-1,3-cyclobutanedione (TMCB). Specifically, isobutyric acid or isobutyric anhydride is used as a raw material to obtain a gaseous product containing dimethyl ketene through thermal cracking reaction, and to directly polymerize it. Background technique [0002] 2,2,4,4-tetramethyl-1,3-cyclobutanedione (TMCB) is mainly used to synthesize 2,2,4,4-tetramethyl-1,3-cyclobutanediol (CBDO) , CBDO can significantly enhance the glass transition temperature of polyester, improve weather resistance and transparency, and is an ideal raw material to replace polycarbonate. The synthesis of TMCB is mainly obtained by cracking isobutyric acid or isobutyric anhydride, absorbing the by-product dimethylketene after cracking, and polymerizing. In the prior art, the absorption tower is used to reversely absorb the cracked gas, and then ...

Claims

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Application Information

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IPC IPC(8): C07C49/39C07C45/76
Inventor 史君程光剑娄阳王红吕洁刘宗琦董大清李民赵晶邸大鹏田振英王咏梅贺俊海琼伟格
Owner PETROCHINA CO LTD
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