The process of isolating methyl-4-formylbenzoate and dimethylterephtalate

A technology of dimethyl terephthalate and methyl formyl benzoate, applied in the field of separation and recovery of 4-formyl in the mixture of by-products, can solve the problems of unfavorable worker safety, environmental problems, corrosion reaction equipment, etc. To achieve the effect of alleviating economic and environmental problems

Inactive Publication Date: 2013-03-27
SK INNOVATION CO LTD +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this method has the following disadvantages: terephthalaldehyde is an expensive starting material; additional work-up is required after the preparation of 4-formylbenzoic acid to remove sulfuric acid, resulting in lower yields in the isolation and purification steps; And need to use catalyst in the addition reaction of methanol, thereby increased the cost of preparation target compound
[0009] However, the method according to said Korean Patent Application No. 2004-13412 has problems in that the use of sodium metabisulfite generates a large amount of sulfur dioxide gas, which corrodes the reaction device and adversely affects the safety of workers, and uses an excessive amount of water and solvents will increase the production cost of MFB
And, also there is such shortcoming: because in order to separate the MFB of high purity, need to use the water of at least eight times of original MBF weight and the solvent of at least twice of original MFB weight respectively, so the production cost of MFB is very high, and produces A large amount of waste water, thus causing environmental problems

Method used

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  • The process of isolating methyl-4-formylbenzoate and dimethylterephtalate
  • The process of isolating methyl-4-formylbenzoate and dimethylterephtalate
  • The process of isolating methyl-4-formylbenzoate and dimethylterephtalate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0035] To 100 parts by weight of a mixture containing about 63% by weight of MFB, about 30% by weight of DMT, about 6% by weight of MPT, about 1% by weight of MBZ and trace impurities is added 200 parts by weight of methanol, the mixture It is a by-product in the process of preparing DMT. The methanol solution was stirred at 25°C for 0.5 hour. After the stirring, only DMT remained as a solid, and the stirred solution was filtered to recover DMT as a solid. The solid DMT was washed with methanol, and the weight of the DMT thus obtained was 27.4 g and the purity was 99.4%.

[0036] To the obtained filtrate was added 0.2 parts by weight of hydrochloric acid (HCl), and the solution was stirred for 2 hours to convert MFB into benzaldehyde dimethylacetal-4-acetate. When the reaction product converted into benzaldehyde dimethyl acetal-4-acetate was kept at -2°C, the residual DMT was precipitated as a solid. The reaction product was filtered at -2°C to recover the remaining solid DMT....

Embodiment 2

[0039] To 100 parts by weight of a mixture containing about 63% by weight of MFB, about 30% by weight of DMT, about 6% by weight of MPT, about 1% by weight of MBZ and trace impurities is added 200 parts by weight of ethanol, the mixture It is a by-product in the process of preparing DMT. The ethanol solution was stirred at 25°C for 0.5 hour. After the stirring, only DMT remained as a solid, and the stirred solution was filtered to recover DMT as a solid. The solid DMT was washed with ethanol, and the weight of the DMT thus obtained was 25.1 g and the purity was 99.6%.

[0040] 0.2 parts by weight of hydrochloric acid (HCl) was added to the obtained filtrate, and the solution was stirred for 2 hours to convert MFB into benzaldehyde dimethyl acetal-4-acetate. When the reaction product converted into benzaldehyde dimethyl acetal-4-acetate was kept at -2°C, the residual DMT was precipitated as a solid. The reaction product was filtered at -2°C to recover the residual DMT as a soli...

Embodiment 3

[0043] MFB was recovered in the same manner as in Example 1, except that the same amount of Exelsol670 (Korea SK Company) was used instead of heptane. In this case, the purity of the recovered DMT was 99.4% and the weight was 29.8 g, and the purity of the recovered MFB was 98.8% and the weight was 39.9 g.

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Abstract

Disclosed is a method of isolating and recovering methyl-4-formylbenzoate (MFB) and dimethyl terephthalate (DMT) at high purity from a mixture of byproducts produced in a process of producing DMT from p-xylene as a starting material through oxidation and esterification reactions. In the method, methyl-4-formylbenzoate (MFB) included in the byproduct mixture is isolated at high purity by converting it into an acetal compound through reaction with alcohol, and DMT is isolated and recovered from the byproduct mixture from which the MFB has been removed. The method does not generate sulfur dioxide gas, which is noxious and corrodes equipment, and in addition, it alleviates economic and environmental problems associated with the use of an excessive amount of solvent and the generation of wastewater.

Description

Technical field [0001] The present invention relates to a method for separating and recovering methyl 4-formyl benzoate and dimethyl terephthalate from a mixture of by-products generated in the process of preparing dimethyl terephthalate, and more Specifically, the present invention relates to a method for separating and recovering high-purity methyl 4-formyl benzoate (hereinafter referred to as "DMT") from the by-products of the production process of dimethyl terephthalate (hereinafter referred to as "DMT"). The method called "MFB") and DMT. The by-products contain MFB, DMT, methyl p-toluate (hereinafter referred to as "MPT") and the like. Background technique [0002] MFB is a white crystal with the smell of aldehyde, easily soluble in acetone, toluene, methylene chloride, etc. It is used as a raw material for the preparation of optical brighteners, aromatic agents, etc., and as a raw material for the preparation of high value-added materials (for example, p-aminobenzoic acid)...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C67/48
CPCC07C67/52C07C67/60C07C69/82C07C69/76C07C67/54
Inventor 高在石金优善刘永甲
Owner SK INNOVATION CO LTD
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