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Method for producing m-cresol with direct hydrolyzation

A hydrolysis method, a technology between production, applied in chemical instruments and methods, preparation of organic compounds, organic chemistry and other directions, can solve the problems of high cost of dilute acid neutralization, consumption of sodium nitrite, serious environmental pollution, etc., to achieve sulfuric acid. The effect of less dosage, less alkali required for neutralization and high product yield

Active Publication Date: 2009-04-08
JIANGSU KESHENG CHEM MACHINERY
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

The disadvantage of this method is: two-step reaction is required to generate m-cresol, and the product yield is low. The synthetic yield is generally below 85%, and the total yield is about 80%; the intermediate product diazonium salt has the danger of easy decomposition and explosion
A large amount of sulfuric acid is consumed in the steps of diazotization reaction and hydrolysis reaction, and the concentration of sulfuric acid generated is low, the concentration of sulfuric acid is between 30-40%, the recovery is difficult, the neutralization cost of dilute acid is high, and the environmental pollution is serious; Consumption of sodium nitrite

Method used

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  • Method for producing m-cresol with direct hydrolyzation

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Effect test

Embodiment 1

[0018] Embodiment 1: produce m-cresol according to the following steps:

[0019] (1) batching, the sulfuric acid that content is 1% and the m-toluidine aqueous solution that content is 1% are added in the autoclave, mix under agitation;

[0020] (2) hydrolyze, stop stirring and heat up, hydrolyze under the condition of 220 ℃ for 8 hours, generate m-cresol and ammonium bisulfate aqueous solution;

[0021] (3) flash evaporation, the above-mentioned hydrolyzate is carried out normal pressure flash evaporation, reclaims part water and uses for (1) step batching;

[0022] (4) neutralize, add dropwise ammonia solution in the reactor, the pH value is adjusted to 3;

[0023] (5) Extraction, the neutralized kettle liquid is extracted with benzene to remove the m-cresol; the water phase after the extraction is distilled out of which water is used for the (1) step ingredients, and the distillation residue is ammonium bisulfate, which can be used as For fertilizer;

[0024] (6) extract...

Embodiment 2

[0026] Embodiment 2: produce m-cresol according to the following steps:

[0027] (1) batching, the sulfuric acid that content is 5% and the m-toluidine aqueous solution that content is 5% are added in the autoclave, mix under agitation;

[0028] (2) hydrolyze, stop stirring and heat up, hydrolyze under the condition of 200 ℃ for 8 hours, generate m-cresol and ammonium bisulfate aqueous solution;

[0029] (3) flash evaporation, the above-mentioned hydrolyzate is carried out normal pressure flash evaporation, reclaims part water and uses for (1) step batching;

[0030] (4) neutralize, add dropwise ammonia solution in the reactor, adjust the pH value to 4;

[0031] (5) Extraction, the neutralized kettle liquid is extracted with toluene to extract m-cresol therein; the water phase after extraction is distilled out of which water is used for (1) step ingredients, and the distillation residue is ammonium bisulfate, which can be used as For fertilizer;

[0032] (6) extraction agen...

Embodiment 3

[0034] Embodiment 3: produce m-cresol according to the following steps:

[0035] (1) batching, the sulfuric acid that content is 10% and the m-toluidine aqueous solution that content is 10% add in autoclave, mix under agitation;

[0036] (2) hydrolyze, stop stirring and heat up, hydrolyze under the condition of 250 ℃ for 8 hours, generate m-cresol and ammonium bisulfate aqueous solution;

[0037] (3) flash evaporation, the above-mentioned hydrolyzate is carried out normal pressure flash evaporation, reclaims part water and uses for (1) step batching;

[0038] (4) Neutralization, adding aqueous sodium hydroxide solution dropwise to the reactor, adjusting the pH value to 5;

[0039] (5) extraction, extract the m-cresol wherein with butyl acetate extraction of the still liquid after neutralization; Water phase distillation after the extraction goes out wherein water is used for the (1) step batching, and distillation residue is ammonium bisulfate, Can be used as fertilizer;

...

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Abstract

The invention discloses a method for producing resordinol through direct hydrolysis. The method comprises the following steps: adding sulphuric acid or hydrochloric acid with certain concentration and meta-toluidine respectively according to a proportion into a blending pot so as to form meta-toluidine sulphate or meta-toluidine hydrochloride; sending the meta-toluidine sulphate or meta-toluidine hydrochloride aqueous solution from the blending pot into a high-pressure kettle; controlling the reaction temperature; carrying out the hydrolysis of the meta-toluidine sulphate or the meta-toluidine hydrochloride; recovering part of water in the hydrolysate through flash evaporation for blending; neutralizing the hydrolysate through ammonia spirit or caustic alkali aqueous solution till reaching a PH value of 3 to 5; carrying out organic extraction on the hydrolysate; and then recovering the extractant and refining coarse resordinol. The method adopts only one-step hydrolysis, thereby greatly reducing the dosage of sulphuric acid, and not using sodium nitrite. The concentration of the dilute sulfuric acid generated in the reaction process is lower than 2 percent. The method has the advantages that the cost of neutralizing the dilute acid is low, and the environmental pollution is also low.

Description

technical field [0001] The invention belongs to the technical field of m-cresol production technology, and more specifically relates to a method for producing m-cresol by direct hydrolysis. Background technique [0002] m-cresol is an important chemical intermediate, mainly used as a pesticide intermediate for the production of insecticides fenitrothion, fenthion, amecarb, permethrin, and also for color films, resins, plasticizers and Intermediates of spices. [0003] In China, m-cresol is mainly carried out by the diazotization hydrolysis method of m-toluidine. This method usually dissolves m-toluidine in sulfuric acid solution, forms a diazonium salt by dropping sodium nitrite solution, and then hydrolyzes the diazonium salt under acidic conditions to generate m-cresol. The shortcoming of this method is: two-step reaction is required to generate m-cresol, and the product yield is low, and the synthetic yield is generally below 85%, and the total yield is about 80%; the i...

Claims

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Application Information

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IPC IPC(8): C07C39/07C07C37/05
Inventor 王武谦刘伯军许如海杨崇高
Owner JIANGSU KESHENG CHEM MACHINERY
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