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Co-production method for methyl benzoic acid and phthalic acid

A technology of toluic acid and phthalic acid, applied in chemical instruments and methods, carboxylate preparation, bulk chemical production, etc., can solve the loss of intermediate product methyl benzyl alcohol, low product purity and yield, solid The large amount of waste residues and other problems can avoid side reactions, improve the utilization rate, and improve the economy.

Active Publication Date: 2016-02-24
山东友道化学有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The post-treatment process in the prior art uses rectification to separate the unreacted raw materials and products, which not only consumes a lot of heat energy, but also the intermediate product tolualdehyde produced in the rectification process is easy to react with the alcohol in the system when heated And loss, the intermediate product methyl benzyl alcohol is easily heated and the acid in the system is esterified and lost, and a large amount of front cuts are produced in the rectification process. These factors combine to cause a large amount of solid waste residue in the distillation tower still, and the purity and quality of the product The yield is low, generally the yield does not exceed 80%, and the purity does not exceed 99%

Method used

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  • Co-production method for methyl benzoic acid and phthalic acid
  • Co-production method for methyl benzoic acid and phthalic acid
  • Co-production method for methyl benzoic acid and phthalic acid

Examples

Experimental program
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Effect test

Embodiment 1

[0068] The catalyst that dissolves in the fresh p-xylene that adds primary oxidation reactor is N-hydroxyphthalimide, the metal phthalocyanine (R with general formula (IV) structure 1 = H, R 2 =H, M=Co), cobalt acetylketone and metalloporphyrin (R 1 = R 2 = R 3 = H, M 1 = M 2 =Mn) with a total concentration of 800 ppm. When the device is in steady state operation, the flow rate of fresh p-xylene entering the primary oxidation reactor is 73.2L / h, the flow rate of the first filtrate rich in eight-carbon oxygenate intermediates is 7.3L / h, and the total flow rate is 80.5L / h. At this moment, the average residence time of the primary oxidation reactor in terms of liquid phase substances is 1.5h, and the pressurized air with an oxygen mass percentage concentration of 21% is continuously passed into the primary oxidation reactor to maintain the system reaction temperature at 120°C. The reaction pressure is 0.5 MPa. The primary oxidation reaction solution is continuously fed in...

Embodiment 2

[0070] The catalyst dissolved in the fresh p-xylene added in the primary oxidation reactor is N-hydroxyphthalimide, cobalt naphthenate, metal phthalocyanine (R) with general formula (IV) structure 1 =OH, R 2 =H, M=Ru) and metalloporphyrins (R 1 = R 3 = H, R 2 =OH,M 1 = M 2 =Mn), the total concentration is 10000ppm. When the device is in steady state operation, the operation process is the same as in Example 1, the operating conditions of the primary oxidation reactor are shown in Table 1, and the operating conditions of the secondary oxidation reactor are shown in Table 2. Under these operating conditions, the quality, purity, yield, yield and conversion of p-xylene of each product obtained are listed in Table 3.

Embodiment 3

[0072] The catalyst dissolved in fresh p-xylene fed to the primary oxidation reactor is CeO 2 , metal phthalocyanines (R) with general formula (IV) structure 1 = H, R 2 =CH 3 CH 2 , M=Mn) and a mixture of cobalt acetate, the total concentration is 450ppm. When the device is in steady state operation, the operation process is the same as in Example 1, the operating conditions of the primary oxidation reactor are shown in Table 1, and the operating conditions of the secondary oxidation reactor are shown in Table 2. Under these operating conditions, the quality, purity, yield, yield and conversion of p-xylene of each product obtained are listed in Table 3.

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Abstract

The invention discloses a co-production method for methyl benzoic acid and phthalic acid. The co-production method comprises the following steps: (1) continuously introducing fresh dimethylbenzene, a catalyst and oxygen-containing gas into a primary oxidation reactor for a reaction to obtain a primary oxidation reaction solution containing methyl benzoic acid and an eight-carbon oxygen-contained compound; (2) carrying out continuous cooling, crystallization and filtration on the primary oxidation reaction solution to obtain filter liquor and filter cake, circulating 1-98% of the filter liquor back the primary oxidation reactor continuously, and continuous rectifying the filter cake continuously, to obtain a low-boiling point front cut fraction, distillation raffinate and a methyl benzoic acid product separately; (3) adding the remaining filter liquor in the step (2) and the obtained front cut fraction and distillation raffinate in the step (2) into a secondary oxidation reactor continuously, and meanwhile continuously introducing a Co / Mn / Br catalyst, acetic acid and oxygen-containing gas into the secondary oxidation reactor for an oxidation reaction to obtain a secondary oxidation reaction mixture; and (4) continuously cooling, crystallizing and filtrating the secondary oxidation reaction mixture to obtain a filter liquor and a phthalic acid product. The co-production method has advantages of a simple process, a low cost, a high yield, good selectivity, good economic benefits, and environmental protection.

Description

technical field [0001] The invention relates to the technical field of fine chemicals, in particular to a method for co-producing toluic acid and phthalic acid. Background technique [0002] Toluene benzoic acid can be used as an intermediate of medicine, pesticide, organic pigment and whitening agent, etc. Its preparation methods mainly include xylene nitric acid oxidation method, xylene air oxidation method, toluene carbonylation-oxidation method, etc., which are the most economical and effective The method is the xylene air oxidation method. Toluic acid can be further oxidized into phthalic acid. Phthalic acid is an important raw material in the polyester industry and a bulk chemical raw material related to the national economy and people's livelihood, but its price is much lower than toluic acid. [0003] In the process of air oxidation of xylene to methyl benzoic acid, the methyl group on xylene is the most inert substance in the reaction system, and the activation of ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C51/265C07C63/04C07C63/16C07C63/24C07C63/26
CPCY02P20/52C07C51/265C07C63/04C07C63/16C07C63/24C07C63/26
Inventor 王勤波熊振华陈楚雄
Owner 山东友道化学有限公司
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