阅读说明：本技术 一种间二氯苯的工业化生产方法 (Industrial production method of m-dichlorobenzene ) 是由 马保方 于 2018-05-30 设计创作，主要内容包括：本发明涉及有机合成技术领域,具体为一种间二氯苯的工业化生产方法,旨在提高产物收率及纯度。其技术方案要点包括将苯和浓硝酸混合,以二氧化锰为催化剂进行催化反应,得到硝基苯；将硝基苯与浓硝酸混合,进行二次催化反应,得到混合硝基苯溶液；将混合硝基苯与亚硫酸氢钠和氢氧化钠进行混合并搅拌,得到间二硝基苯；向间二硝基苯中通入氯气,得到粗的间二氯苯溶液；将间二氯苯溶液通过疏水硅沸石分子筛进行除杂处理；然后结晶、精馏除杂、二次氯化,得到纯的间二氯苯；最后冷凝处理,得到成品并收集。(The invention relates to the technical field of organic synthesis, in particular to an industrial production method of m-dichlorobenzene, aiming at improving the yield and purity of products. The key points of the technical scheme comprise that benzene and concentrated nitric acid are mixed, and catalytic reaction is carried out by taking manganese dioxide as a catalyst to obtain nitrobenzene; mixing nitrobenzene and concentrated nitric acid, and carrying out secondary catalytic reaction to obtain a mixed nitrobenzene solution; mixing and stirring the mixed nitrobenzene, sodium bisulfite and sodium hydroxide to obtain m-dinitrobenzene; introducing chlorine into m-dinitrobenzene to obtain a crude m-dichlorobenzene solution; removing impurities from the m-dichlorobenzene solution by using a hydrophobic silicon zeolite molecular sieve; then crystallizing, rectifying to remove impurities, and secondarily chlorinating to obtain pure m-dichlorobenzene; and finally, carrying out condensation treatment to obtain a finished product and collecting the finished product.)

1. An industrial production method of m-dichlorobenzene is characterized in that: the method comprises the following steps:

S1: mixing benzene and concentrated nitric acid, and carrying out catalytic reaction by using manganese dioxide as a catalyst to obtain nitrobenzene;

S2: adding concentrated nitric acid into the nitrobenzene obtained in the step S1 for mixing, and then adding manganese dioxide for secondary catalytic reaction to obtain a mixed nitrobenzene solution containing o-dinitrobenzene, p-dinitrobenzene and m-dinitrobenzene;

S3: mixing and stirring the mixed nitrobenzene obtained in the step S2 with a mixed solution of sodium bisulfite and sodium hydroxide, and then washing and centrifugally separating to obtain m-dinitrobenzene;

s4: introducing chlorine into m-dinitrobenzene in S3 to perform chlorination reaction of the m-dinitrobenzene in a chlorination kettle to obtain a crude m-dichlorobenzene solution;

S5: adsorbing and removing impurities from the m-dichlorobenzene solution in the S4 by using a hydrophobic silicon zeolite molecular sieve;

S6: feeding the solution subjected to impurity removal in the S5 into a crystallization kettle for crystallization treatment;

S7: feeding the m-dichlorobenzene crystallized in the S6 into a rectifying tower for rectification and impurity removal;

S8: condensing the m-dichlorobenzene subjected to impurity removal in S7, introducing chlorine, and carrying out secondary chlorination reaction to obtain pure m-dichlorobenzene;

S9: and (4) feeding m-dichlorobenzene obtained in the S8 into a condenser for condensation treatment to obtain a finished product, and collecting the finished product.

2. The method for industrially producing m-dichlorobenzene according to claim 1, wherein the reaction is carried out by the following steps: the mass ratio of benzene to concentrated nitric acid in S1 is 1 (1-1.2).

3. The method for industrially producing m-dichlorobenzene according to claim 1, wherein the reaction is carried out by the following steps: the mass ratio of nitrobenzene to concentrated nitric acid in S2 is 1 (1-1.2).

4. The method for industrially producing m-dichlorobenzene according to claim 1, wherein the reaction is carried out by the following steps: the mass ratio of the sodium bisulfite to the sodium hydroxide added in S3 is 1 (1-1.5).

5. the method for industrially producing m-dichlorobenzene according to claim 1, wherein the reaction is carried out by the following steps: the washing and centrifugation process in S3 was: firstly, the mixed solution is washed and centrifugally separated for many times by using dilute ammonia water, then, the mixed solution is washed for the second time by using distilled water, and then, centrifugal separation is carried out.

6. The method for industrially producing m-dichlorobenzene according to claim 1, wherein the reaction is carried out by the following steps: the reaction temperature of the chlorination kettle in the S4 is controlled at 230 ℃ and 250 ℃ during the chlorination reaction.

7. The method for industrially producing m-dichlorobenzene according to claim 1, wherein the reaction is carried out by the following steps: the temperature in the crystallization kettle in S6 was 115 ℃.

8. the method for industrially producing m-dichlorobenzene according to claim 1, wherein the reaction is carried out by the following steps: the reaction temperature of the secondary chlorination reaction in S8 was 230 ℃.

Technical Field

the invention relates to the technical field of organic synthesis, in particular to an industrial production method of m-dichlorobenzene.

Background

The m-dichlorobenzene is colorless liquid, has pungent smell, is insoluble in water, and is soluble in alcohol and ether. Can carry out chlorination, nitration, sulfonation and hydrolysis reactions, and the reaction is violent when meeting aluminum. At present, the commonly used method for producing m-dichlorobenzene mainly comprises the steps of directly carrying out chlorination process by taking benzene as a raw material, and then carrying out treatment of procedures such as crystallization, rectification and the like to produce the m-dichlorobenzene.

Disclosure of Invention

The invention aims to provide an industrial production method of m-dichlorobenzene, aiming at improving the yield and purity of products.

The technical purpose of the invention is realized by the following technical scheme:

An industrial production method of m-dichlorobenzene comprises the following steps:

S1: mixing benzene and concentrated nitric acid, and carrying out catalytic reaction by using manganese dioxide as a catalyst to obtain nitrobenzene;

S2: adding concentrated nitric acid into the nitrobenzene obtained in the step S1 for mixing, and then adding manganese dioxide for secondary catalytic reaction to obtain a mixed nitrobenzene solution containing o-dinitrobenzene, p-dinitrobenzene and m-dinitrobenzene;

S3: mixing and stirring the mixed nitrobenzene obtained in the step S2 with a mixed solution of sodium bisulfite and sodium hydroxide, and then washing and centrifugally separating to obtain m-dinitrobenzene;

S4: introducing chlorine into m-dinitrobenzene in S3 to perform chlorination reaction of the m-dinitrobenzene in a chlorination kettle to obtain a crude m-dichlorobenzene solution;

S5: adsorbing and removing impurities from the m-dichlorobenzene solution in the S4 by using a hydrophobic silicon zeolite molecular sieve;

s6: feeding the solution subjected to impurity removal in the S5 into a crystallization kettle for crystallization treatment;

s7: feeding the m-dichlorobenzene crystallized in the S6 into a rectifying tower for rectification and impurity removal;

s8: condensing the m-dichlorobenzene subjected to impurity removal in S7, introducing chlorine, and carrying out secondary chlorination reaction to obtain pure m-dichlorobenzene;

S9: and (4) feeding m-dichlorobenzene obtained in the S8 into a condenser for condensation treatment to obtain a finished product, and collecting the finished product.

Further, the mass ratio of benzene to concentrated nitric acid in S1 is 1 (1-1.2).

Further, the mass ratio of nitrobenzene to concentrated nitric acid in S2 is 1 (1-1.2).

further, the mass ratio of sodium bisulfite to sodium hydroxide added in S3 is 1 (1-1.5).

further, the washing and centrifugation process in S3 is: firstly, the mixed solution is washed and centrifugally separated for many times by using dilute ammonia water, then, the mixed solution is washed for the second time by using distilled water, and then, centrifugal separation is carried out.

Further, the reaction temperature of the chlorination kettle in S4 is controlled at 230-250 ℃ during the chlorination reaction.

further, the temperature in the crystallization tank in S6 was 115 ℃.

Further, the reaction temperature of the secondary chlorination reaction in S8 was 230 ℃.

The method for producing m-dichlorobenzene provided by the invention adopts benzene as a raw material, and finally produces the m-dichlorobenzene product with higher purity through twice nitration reaction and repeated chlorination reaction.

Detailed Description

The technical solution of the present invention will be clearly and completely described below with reference to specific embodiments. It is to be understood that the described embodiments are merely a few embodiments of the invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments of the present invention without any inventive step, are within the scope of the present invention.

The invention discloses an industrial production method of m-dichlorobenzene, which specifically comprises the following steps.