Method for preparing BDO/succinic acid diester and phthalandione diester with by-product from benzoic anhydride preparation

A technology combining phthalic acid diester and succinic acid diester, which is applied in the field of waste water and residue treatment of chemical synthesis, can solve the problems of low yield, large consumption of methanol, difficult preparation, etc., and achieves low cost and reduced discharge. , The effect of the process is simple and controllable

Inactive Publication Date: 2009-01-14
隆鑫
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

For waste residue and phthalic anhydride residue, due to the difficulty of preparation, they are basically not used. Only a small number of factories use maleic anhydride or fumaric acid to directly esterify with methanol, and then crystallize to obtain dimethyl fumarate; Or the impact of phthalic acid, so that the consumption of methanol is large, the yield is low, and only the maleic anhydride or fumaric acid in it is recycled, and the economic benefit is not good

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] Present embodiment is the method for preparing BDO and diethyl phthalate with the by-product (waste water) that phthalic anhydride is produced, and concrete method is as follows:

[0028] Add 900 liters of phthalic anhydride waste water in a 1000 liter reactor, reduce the pressure to 40 mmHg, distill and remove water, continuously replenish phthalic anhydride waste water in the process, until the concentrate after most of the water is evaporated reaches a volume of about 300 liters, and the acid concentration exceeds 70% ( Calculated by maleic acid, percentage by weight, the same below), continue to heat up to 120 ° C of internal temperature, stop heating when there is no longer gas to evaporate, and remove the vacuum;

[0029] Add 650 liters of ethanol and 20 kg of concentrated sulfuric acid to the above concentrate, heat and reflux for 8 hours, evaporate and recover most of the ethanol, cool, adjust the pH value to neutral with NaOH solution, continue distillation, and...

Embodiment 2

[0032] Present embodiment is the method for preparing diethyl succinate and diethyl phthalate with the by-product (waste water) that phthalic anhydride is produced, and concrete method is as follows:

[0033] Add 900 liters of phthalic anhydride waste water in a 1000 liter reactor, reduce the pressure to 40 mmHg, distill and remove water, constantly replenish phthalic anhydride waste water in the process, until the concentrate after most of the water is evaporated reaches a volume of about 500 liters, and the acid concentration exceeds 50% ( According to maleic acid), add water to 1000 liters, add 6 kg of thiourea, continue to heat up and reflux for 3 hours, cool, crystallize, centrifuge, and dry the solid for subsequent use;

[0034] Weigh 250 kg of the solid prepared by the above method, add 650 liters of ethanol, 20 kg of concentrated sulfuric acid, heat and reflux for 8 hours, evaporate and recover most of the ethanol, cool, adjust the pH value to neutral with NaOH solution...

Embodiment 3

[0037] Present embodiment is the method for preparing BDO and diethyl phthalate with the by-product (waste water) that phthalic anhydride is produced, and concrete method is as follows:

[0038] Add 900 liters of phthalic anhydride wastewater into a 1000 liter reactor, reduce the pressure to 40mmHg, distill off the water, replenish phthalic anhydride wastewater in the process, until the volume of the concentrate after most of the water is evaporated reaches about 800 liters, and the acid concentration exceeds 5%. After (according to maleic acid), continue to heat up and reflux for 24 hours, cool, crystallize, centrifuge, and dry the solid for subsequent use;

[0039] Weigh 250 kg of the solid prepared by the method in the previous step, add 650 liters of ethanol, 20 kg of concentrated sulfuric acid, heat and reflux for 8 hours, steam out and recover most of the ethanol, cool, adjust the pH value to neutral with NaOH solution, continue distillation, and collect 190 Fraction 1 a...

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PUM

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Abstract

The invention discloses a method for using by-products of phthalic anhydride to prepare BDO / succinic acid diester and phthalic acid diester, wherein, the by-products comprise at least one of wastewater, waste residues and phthalic anhydride residues, a preparation method thereof includes the major steps of esterification, distillation, reduction, etc., thereby obtaining a phthalic acid diester product, and also a BDO or succinic acid diester product. The method can fully recycle phthalic anhydride, phthalic acid, maleic anhydride, fumaric acid, maleic acid, succinic acid, etc. in the by-products such as wastewater, waste residues and phthalic anhydride residues in the production process of phthalic anhydride, thereby obtaining products such as chemical intermediate BDO or succinic acid diester and phthalic acid diester with great market demands, and maximally reducing the discharge of wastes; and the preparation method has advantages of simple and controllable technical process and rather low cost.

Description

technical field [0001] The invention belongs to the technical field of waste water and residue treatment of chemical synthesis, and in particular relates to a method for preparing BDO / succinic acid diester and phthalic acid diester from by-products produced by phthalic anhydride. Background technique [0002] The production methods of phthalic anhydride mainly include naphthalene oxidation and o-xylene oxidation. In the process of production, purification, equipment cleaning, etc., some acidic by-products will be produced. These acidic by-products are called wastewater after being dissolved in water, mainly containing succinic acid, butyric acid, acetic acid, maleic acid, fumaric acid, o-phthalic acid Diformic acid and partial oxidation coupling products, etc.; the solids that are automatically precipitated from long-term (usually more than three months to several years) stored waste water are called waste residues, mainly containing phthalic acid, fumaric acid, and a small ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C31/20C07C29/74C07C69/40C07C69/80C07C67/08C07C67/48
Inventor 曾德超
Owner 隆鑫
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