Azeotropy process for catalyzing, rectifying and hydrolyzing methyl acetate

A technology of methyl acetate and rectified water, applied in chemical instruments and methods, preparation of organic compounds, preparation of carboxylate/lactone, etc., can solve the problems of complex process and high energy consumption, and reduce energy consumption of tower stills , the effect of short process flow

Active Publication Date: 2008-11-19
CHINA PETROLEUM & CHEM CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The technical problem to be solved by the present invention is the problem of complex process flow and high energy consumption in the prior art methyl acetate catalytic rectification hydrolysis process, and a new azeotropic method for methyl acetate catalytic rectification hydrolysis is provided. It has the characteristics of simple process and low energy consumption

Method used

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  • Azeotropy process for catalyzing, rectifying and hydrolyzing methyl acetate
  • Azeotropy process for catalyzing, rectifying and hydrolyzing methyl acetate
  • Azeotropy process for catalyzing, rectifying and hydrolyzing methyl acetate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] according to figure 1 The flow shown: the number of theoretical plates of the catalytic rectification tower is 15, among which 10 theoretical plates in the upper part of the tower are filled with catalysts. Methyl acetate and water enter the catalytic rectification tower at a flow rate of 1 kg / h and 1.4 kg / h respectively, the reflux flow at the top of the tower is 8 kg / h, the temperature at the top of the tower is controlled at 87-92°C, and the output from the tower reactor enters the theoretical In a dealcoholization tower with 50 plates, the feeding position is the 30th theoretical plate, the reflux ratio is 2, the temperature at the top of the tower is 80-85°C, the distillate at the top of the tower is aqueous methanol, and the output from the tower is aqueous acetic acid. The methanol aqueous solution enters the alcohol refining tower, the number of theoretical plates is 15, the feeding position is the 10th tray, the reflux ratio is 6, the temperature at the top of ...

Embodiment 2

[0019] The number of theoretical plates in the catalytic rectification tower is 45, of which 12 theoretical plates in the upper part of the tower are filled with catalysts. Methyl acetate and water enter the catalytic rectification tower at a flow rate of 1 kg / h and 1.2 kg / h respectively, the top reflux flow rate is 2 kg / h, and the temperature at the top of the tower is controlled to be 87-92°C. The operating parameters are as in Example 1, and the analysis results of each stream and the energy consumption of each tower are shown in Table 3 and Table 4, respectively.

[0020] The analysis result (mass %) of each stream of table 3

[0021]

[0022] The energy consumption of each tower of table 4 (megajoules / hour)

[0023]

Embodiment 3

[0025] Only change the condition of dealcoholization tower, other each condition is as embodiment 1. The theoretical plate number of the dealcoholization tower is 10, the feeding position is the sixth theoretical plate, the reflux ratio is 8, and the temperature at the top of the tower is controlled at 80-85°C. After stable operation, the analysis results of each stream and the temperature of each tower The energy consumption is shown in Table 5 and Table 6, respectively.

[0026] The analysis result (mass %) of each stream of table 5

[0027]

[0028] The energy consumption of each tower of table 6 (megajoules / hour)

[0029]

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Abstract

The invention relates to an azeotropic method used in methyl acetate catalyzing rectification hydrolysis, mainly solving the problems of the prior methyl acetate catalyzing rectification hydrolysis process including complex flows and high energy consumption. The azeotropic method solves the problems better through adopting the technical proposal which comprises the following steps that: water and methyl acetate are mixed and fed in a catalyzing rectification tower from the top of the tower; the top of the tower is of total reflux and a mixture comprising methanol, acetic acid and water is obtained inside a tower bottom; the mixture is fed in a dealcoholization tower, and the distillate at the top of the dealcoholization tower is a methanol aqueous solution, while an acetic aqueous solution is obtained inside a tower bottom; the methanol aqueous solution is fed in an alcohol treating tower, and the distillate at the top of the alcohol treating tower is methanol, while waste water is generated inside a tower bottom; the acetic aqueous solution is fed in an azeotropic rectification tower which takes one sort of benzene, cyclohexane, isopropyl acetate and n-butyl acetate as an azeotropic agent; a biphase mixture of the azeotropic agent and water is obtained inside the top phase splitter of the azeotropic rectification tower with the water collected from the top of the tower and the azeotropic agent returned to the inside of the tower, while pure acetic acid is obtained inside the tower bottom of the azeotropic rectification tower. The azeotropic method can be used in the industrial production for reclaiming byproduct methyl acetate during producing polyvinyl alcohol.

Description

technical field [0001] The invention relates to an azeotropic method for catalytic rectification and hydrolysis of methyl acetate. Background technique [0002] There is a large amount of by-product methyl acetate in the production process of polyvinyl alcohol. It is estimated that 1.5-1.7 tons of methyl acetate will be produced for every ton of polyvinyl alcohol produced. Due to the small industrial use of methyl acetate, it needs to be hydrolyzed into acetic acid and methanol. After separation and purification, methanol is used in the polymerization process of vinyl acetate, and acetic acid is used in the synthesis of vinyl acetate. In the past, domestic and foreign manufacturers all adopted the fixed-bed methyl acetate hydrolysis process with ion exchange resin as the catalyst. The disadvantage of this process is that the single-pass conversion rate is low (the hydrolysis rate can only reach 23% to 24%), a large amount of unreacted methyl acetate needs to be recycled, th...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C27/02C07C51/09C07C53/08C07C31/04
CPCY02P20/10
Inventor 钟禄平肖剑钟思青顾军民张惠明
Owner CHINA PETROLEUM & CHEM CORP
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