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2‑(4‑methylphenyl)‑benzoxazole synthesis process wastewater recycling method

A technology of methyl phenyl and benzoxazole, which is applied in the field of recovery and treatment of p-toluic acid and o-aminophenol, and can solve the problems of unseen recovery and utilization

Active Publication Date: 2017-09-29
HUBEI HONGXIN CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Previously, the water produced by the synthesis reaction was generally discharged directly to the sewage station for treatment, and there was no report on its economical and effective recycling

Method used

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  • 2‑(4‑methylphenyl)‑benzoxazole synthesis process wastewater recycling method

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Experimental program
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Effect test

Embodiment 1-3

[0026] Embodiments 1-3 are the recovery and treatment methods of p-toluic acid and o-aminophenol in 2-(4-methylphenyl)-benzoxazole synthesis process wastewater

[0027] specifically:

Embodiment 1

[0029] Take 500ml of condensation process reaction synthesis water collected in the workshop (about 20-30 times the volume of the resin), acidify it to pH 1.5 with dilute hydrochloric acid, stir, the solution turns from dark green to red, and there is yellow precipitation, filter, and recover the yellow color 2.35g of crude p-toluic acid (purity 94.52%, HPLC); the filtrate was adjusted to pH 6 with 20% sodium sulfite solution, and the color of the solution changed from red to dark yellow, and then continued to adjust the pH with 20% sodium hydroxide solution When the value reaches 8.5-9, use adsorption resin (CD101 resin) to pass through the column at a speed of 30-40ml / h for adsorption. 50ml hydrochloric acid solution for elution and analysis, the elution speed is the same as that of the column, the eluate is neutralized with 40% sodium hydroxide and the pH value is adjusted to 8.5-9, and concentrated under reduced pressure to 1 / 3-1 / 2 of the original volume , the temperature ...

Embodiment 2

[0031] Take 500ml of condensation process reaction synthesis water collected in the workshop (about 20-30 times the volume of the resin), acidify it to pH 1.5 with dilute hydrochloric acid, stir, the solution turns from dark green to red, and there is yellow precipitation, filter, and recover the yellow color 2.33g of crude p-toluic acid (purity 94.50%, HPLC); the filtrate was adjusted to pH 6 with 30% sodium hydrosulfide solution, the color of the solution changed from red to dark yellow, and then continued with 20% sodium hydroxide solution Adjust the pH value to 8.5-9, and use the adsorption resin (CD101 resin) to pass through the column at a speed of 30-40ml / h for adsorption. 50ml of 15% hydrochloric acid solution for elution, the elution speed is the same as that of the column, the eluate is neutralized by 40% sodium hydroxide and the pH value is adjusted to 8.5-9, and concentrated under reduced pressure to 1 / 3-1 / 3 of the original volume 2. Lower the temperature to precip...

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Abstract

The invention relates to a recycling and treating method of p-toluic acid and ortho-aminophenol in wastewater of a process for synthesizing 2-(4-methyl phenyl)-benzoxazole by taking the p-toluic acid and the ortho-aminophenol as raw materials. The method is characterized by comprising the steps that p-toluic acid precipitates are firstly precipitated out through acidification, and the p-toluic acid is recycled through filtration; filtrate is treated with a reducing agent, the pH value of the filtrate is regulated to be alkali, adsorption is performed with adsorbent resin, elution and analysis are performed, the pH of eluant is regulated to 8.5-9, concentrating and temperature lowering are performed to precipitate phenol out, and filtration is performed to obtain the ortho-aminophenol. According to the method, the p-toluic acid and the ortho-aminophenol in the process wastewater can be economically and effectively recycled, the purity of the p-toluic acid and the purity of the ortho-aminophenol can reach 94.5% or above and 95.8% or above respectively, and the p-toluic acid and the ortho-aminophenol can directly serve as the raw materials to be put and used over and over again in a condensation reaction; organic solvent is not related and used in the treatment process, secondary environmental pollution is not generated, cleanliness and environmental protection are achieved.

Description

technical field [0001] The invention relates to a method for treating industrial wastewater, in particular to a method for recovering and treating p-toluic acid and o-aminophenol in synthetic process wastewater. Background technique [0002] 2-(4-methylphenyl)-benzoxazole is a kind of synthetic fluorescent whitening agent OB-1 (2,2'-(4,4'-distyryl)bisbenzoxazole) important precursors. The existing synthesis method is to dissolve p-toluic acid and o-aminophenol in solvent oil in a reaction kettle, use boric acid as a catalyst, feed nitrogen, heat up to 140-160°C for dehydration condensation, and generate 2-(4-methyl phenyl)-benzoxazole. Its synthesis principle is as follows: [0003] [0004] Using the above production process, through the two-step reaction of intermolecular condensation dehydration and intramolecular condensation dehydration, the water generated during the reaction is continuously separated through the water separator to facilitate the further completi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/04C07C63/04C07C51/487C07C215/76C07C213/00C07C213/10C02F103/36
CPCC02F1/285C02F1/66C02F1/70C02F9/00C02F2103/36C07C51/487C07C213/00C07C213/10C07C63/04C07C215/76
Inventor 王斌李德宝杨玉忠
Owner HUBEI HONGXIN CHEM CO LTD
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