Recycling treatment method for separating byproduct rich meta-position from mixed dichlorobenzene

Abstract

The invention relates to a recycling treatment method for separating a byproduct rich meta-position from mixed dichlorobenzene. The method comprises the following steps: performing acylation reaction for the mixed dichlorobenzene comprising m-dichlorobenzene and acetic anhydride in the presence of anhydrous aluminum chloride, and then hydrolyzing, washing, distilling and crystallizing to obtain 2,4-dichloroacetophenone and little dichlorobenzene; performing catalytic orientation isomerization for the little dichlorobenzene by utilizing a high-efficiency HZSM-5 molecular sieve, enabling p / o-dichlorobenzene to be transpositioned to m-dichlorobenzene, wherein the obtained m-dichlorobenzene can be used for producing 2,4-dichloroacetophenone. The recycling treatment method has the advantages that since the price of the m-dichlorobenzene is high, the m-dichlorobenzene in the mixed dichlorobenzene is sufficiently utilized to be treated at the process route, the raw material utilization rate can be effectively increased, not only can the environment be protected, but also partial market demand on the 2,4-dichloroacetophenone can be satisfied, and the social benefit and the economic value are relatively high.

Description

technical field

[0001] The invention belongs to the technical field of separation engineering, and particularly relates to a mixed dichlorobenzene separation auxiliary

[0002] Resource processing method for producing rich meta positions. Background technique

[0003] Industrial production of p-dichlorobenzene and o-dichlorobenzene mostly adopts chlorobenzene directional chlorination method, but it is easy to form mixed dichlorobenzene, because the boiling points of p-dichlorobenzene, o-dichlorobenzene and m-dichlorobenzene are similar, it is difficult to effectively Separation, the by-product after separation still contains a large amount of m-dichlorobenzene and a small amount of p-dichlorobenzene and o-dichlorobenzene, commonly known as rich meta-position.

[0004] At present, the method of obtaining m-dichlorobenzene by indirect adsorption method using adsorbents such as zeolite and then desorption has been seen in China, but this method has high energy consumption; and...

Examples

Embodiment 1

[0015] 1.2mol of mixed dichlorobenzene containing 70-78wt% m-dichlorobenzene was added to the reaction kettle, 1.5mol of anhydrous aluminum trichloride was added, 1.1mol of acetic anhydride was slowly added dropwise with stirring, and the temperature of the reaction solution was maintained during the dropwise addition. At 55°C, the temperature was raised to 96°C at a rate of 2°C / min at the end of the dropwise addition, and the reaction was stirred under reflux for 4 hours. After the reaction, 200 ml of hydrochloric acid with a mass concentration of 10% was added to the reaction solution to hydrolyze at 80°C, and left to cool. Layered, separated the organic layer, added dropwise to a washing kettle with 200ml of water, washed with water at 50°C, left to stand for stratification, the product was distilled under reduced pressure at 120°C, collected the first fraction at 115°C, and removed the light components to the two. Chlorobenzene, o-dichlorobenzene and a small amount of m-dic...

Embodiment 2

[0018] 1.2mol of mixed dichlorobenzene containing 70-78wt% m-dichlorobenzene was added to the reaction kettle, 1.5mol of anhydrous aluminum trichloride was added, 1.1mol of acetic anhydride was slowly added dropwise with stirring, and the temperature of the reaction solution was maintained during the dropwise addition. At 59°C, the temperature was raised to 92°C at a rate of 1°C / min at the end of the dropwise addition, and the reaction was stirred under reflux for 3 hours. After the reaction, 200 ml of hydrochloric acid with a mass concentration of 10% was added to the reaction solution to hydrolyze at 80°C, and placed to cool. Layered, separated the organic layer, added dropwise to a washing kettle containing 200ml of water and washed with water at 50°C. After standing for stratification, the product was distilled under reduced pressure at 110°C. Chlorobenzene, o-dichlorobenzene and a small amount of m-dichlorobenzene mixture, referred to as dichlorobenzene, and then crystalli...

Embodiment 3

[0021] 1.2mol of mixed dichlorobenzene containing 70-78wt% m-dichlorobenzene was added to the reaction kettle, 1.5mol of anhydrous aluminum trichloride was added, 1.1mol of acetic anhydride was slowly added dropwise with stirring, and the temperature of the reaction solution was maintained during the dropwise addition. At 57°C, the temperature was raised to 94°C at a rate of 1°C / min at the end of the dropwise addition, and the reaction was stirred under reflux for 4 hours. After the reaction, 200ml of hydrochloric acid with a mass concentration of 10% was added to the reaction solution to hydrolyze at 80°C, and left to cool. Layered, separated the organic layer, added dropwise to a washing kettle containing 200ml of water and washed with water at 50°C. After standing for stratification, the product was distilled under reduced pressure at 115°C. Chlorobenzene, o-dichlorobenzene and a small amount of m-dichlorobenzene mixture, referred to as dichlorobenzene, are cooled and crysta...

technical field

[0001] The invention belongs to the technical field of separation engineering, and particularly relates to a mixed dichlorobenzene separation auxiliary

[0002] Resource processing method for producing rich meta positions. Background technique

[0003] Industrial production of p-dichlorobenzene and o-dichlorobenzene mostly adopts chlorobenzene directional chlorination method, but it is easy to form mixed dichlorobenzene, because the boiling points of p-dichlorobenzene, o-dichlorobenzene and m-dichlorobenzene are similar, it is difficult to effectively Separation, the by-product after separation still contains a large amount of m-dichlorobenzene and a small amount of p-dichlorobenzene and o-dichlorobenzene, commonly known as rich meta-position.

[0004] At present, the method of obtaining m-dichlorobenzene by indirect adsorption method using adsorbents such as zeolite and then desorption has been seen in China, but this method has high energy consumption; and...

Examples

Embodiment 1

[0015] 1.2mol of mixed dichlorobenzene containing 70-78wt% m-dichlorobenzene was added to the reaction kettle, 1.5mol of anhydrous aluminum trichloride was added, 1.1mol of acetic anhydride was slowly added dropwise with stirring, and the temperature of the reaction solution was maintained during the dropwise addition. At 55°C, the temperature was raised to 96°C at a rate of 2°C / min at the end of the dropwise addition, and the reaction was stirred under reflux for 4 hours. After the reaction, 200 ml of hydrochloric acid with a mass concentration of 10% was added to the reaction solution to hydrolyze at 80°C, and left to cool. Layered, separated the organic layer, added dropwise to a washing kettle with 200ml of water, washed with water at 50°C, left to stand for stratification, the product was distilled under reduced pressure at 120°C, collected the first fraction at 115°C, and removed the light components to the two. Chlorobenzene, o-dichlorobenzene and a small amount of m-dic...

Embodiment 2

[0018] 1.2mol of mixed dichlorobenzene containing 70-78wt% m-dichlorobenzene was added to the reaction kettle, 1.5mol of anhydrous aluminum trichloride was added, 1.1mol of acetic anhydride was slowly added dropwise with stirring, and the temperature of the reaction solution was maintained during the dropwise addition. At 59°C, the temperature was raised to 92°C at a rate of 1°C / min at the end of the dropwise addition, and the reaction was stirred under reflux for 3 hours. After the reaction, 200 ml of hydrochloric acid with a mass concentration of 10% was added to the reaction solution to hydrolyze at 80°C, and placed to cool. Layered, separated the organic layer, added dropwise to a washing kettle containing 200ml of water and washed with water at 50°C. After standing for stratification, the product was distilled under reduced pressure at 110°C. Chlorobenzene, o-dichlorobenzene and a small amount of m-dichlorobenzene mixture, referred to as dichlorobenzene, and then crystalli...

Embodiment 3

[0021] 1.2mol of mixed dichlorobenzene containing 70-78wt% m-dichlorobenzene was added to the reaction kettle, 1.5mol of anhydrous aluminum trichloride was added, 1.1mol of acetic anhydride was slowly added dropwise with stirring, and the temperature of the reaction solution was maintained during the dropwise addition. At 57°C, the temperature was raised to 94°C at a rate of 1°C / min at the end of the dropwise addition, and the reaction was stirred under reflux for 4 hours. After the reaction, 200ml of hydrochloric acid with a mass concentration of 10% was added to the reaction solution to hydrolyze at 80°C, and left to cool. Layered, separated the organic layer, added dropwise to a washing kettle containing 200ml of water and washed with water at 50°C. After standing for stratification, the product was distilled under reduced pressure at 115°C. Chlorobenzene, o-dichlorobenzene and a small amount of m-dichlorobenzene mixture, referred to as dichlorobenzene, are cooled and crysta...