CN103360229A - Method for preparing 2-ethylanthraquinone by continuous 2-(4-alkylbenzoyl)benzoic acid ring-closing reaction - Google Patents

Abstract

The invention discloses a method for preparing 2-ethylanthraquinone by continuous 2-(4-alkylbenzoyl)benzoic acid ring-closing reaction, the method is liquid 2-(4-alkylbenzoyl)benzoic acid quality and room temperature The volume ratio of the concentrated sulfuric acid is 1:1.5-1:2.5, mixed in the mixer, the mixing temperature is room temperature-100°C, the residence time of the mixture in the mixer is 1-10min, the mixer is connected in series with the stirring reactor, For the ring-closing reaction, the temperature of the stirring reactor is 100-140°C, the residence time of the reaction material in the reactor is 5-30min, and the liquid after the reaction is directly hydrolyzed, extracted, and distilled to obtain 2-ethylanthraquinone. See the instruction manual for detailed methods. The advantages of the invention are: the process is simple to operate, easy to control, reduces labor intensity, improves the working environment, reduces equipment investment, reduces the amount of waste acid, and the yield of the product is increased by 5-10% compared with the existing production process, and the product quality is improved. good.

Description

Method for preparing 2-ethylanthraquinone by continuous 2-(4-alkylbenzoyl) benzoic acid ring-closing reaction

technical field

The invention belongs to the production process of fine chemical products, in particular to a method for preparing 2-ethylanthraquinone by continuous 2-(4-alkylbenzoyl) benzoic acid ring-closing reaction.

Background technique

2-Ethylanthraquinone is a light yellow powder or bright yellow scale solid, which is an important fine chemical raw material, mainly used as a hydrogen peroxide synthesis catalyst, and also used to prepare photosensitive compounds, dyes, optical sieve resins, pharmaceutical and pesticide intermediates and other fields. With the increasing demand for hydrogen peroxide, especially the rapid development of the paper industry, 2-ethylanthraquinone has become a fine chemical with considerable development potential.

At present, the methods for producing 2-ethylanthraquinone mainly include: (1) Ethylanthracene direct oxidation method: This method uses hydrochloric acid as a catalyst, and hydrogen peroxide is used to oxidize 2-ethylanthracene in liquid phase to generate 2-ethylanthracene in one step. Anthraquinone. The yield of the oxidation method can reach 96% to 98.0%, but since 2-ethylanthracene is transformed from 2-ethylanthraquinone, there is very little 2-ethylanthracene in nature, so it has no meaning for industrial production. (2) 2-formyl anthraquinone conversion method: In this method, 2-formyl anthraquinone is condensed with malonic acid in the presence of pyridine, and then decarboxylated in the presence of copper to further catalyze the formation of 2-ethyl anthraquinone. This method not only has many synthesis steps, but also is difficult to industrialize due to the difficulty in the source of raw materials. (3) Friedel-Crafts method: This method is mainly divided into two steps. First, ethylbenzene and phthalic anhydride are used as raw materials to synthesize 2-(4-ethylbenzoyl)benzoic acid (BE acid) under the action of AlCl3. ), and then under the action of oleum, the BE acid dehydrates and closes the ring to generate 2-ethylanthraquinone. Due to the rapid development of petrochemical industry, sufficient sources of ethylbenzene and phthalic anhydride provide sufficient raw materials for the Friedel-Crafts method. Therefore, the Friedel-Crafts method has become the main production method of 2-ethylanthraquinone in my country. From the viewpoint of "greening", it is necessary to further strengthen and improve the process of Friedel-Crafts method. Due to the small production scale and serious pollution of 2-ethylanthraquinone in my country, it cannot meet the industrial needs such as hydrogen peroxide. Therefore, a large amount of high-quality 2-ethylanthraquinone needs to be imported every year to make up for the shortfall in demand. At present, the Friedel-Crafts method is widely used in my country to synthesize 2-ethylanthraquinone. This method has the disadvantages of large amount of three wastes and serious corrosion. Many researchers at home and abroad have studied the Friedel-Crafts method for the synthesis of 2-ethylanthraquinone. The main purpose is to strengthen the alkylation and ring-closure reaction process and realize the cleanliness of the 2-ethylanthraquinone synthesis industry.

CN 1315768C (2007-05-16) and CN 1879965A (2006-12-20) patents introduce the use of solid acid as a catalyst to catalyze the dehydration and ring closure of 2-(4-ethylbenzoyl)benzoic acid to generate 2-alkylanthracene The method of quinone, but although this method can solve the problem of environmental pollution, there is still a big gap from the requirements of industrialization.

CN102050716A (2010-11-18) patent introduces a method for separating and purifying 2-ethylanthraquinone from sulfuric acid. This method is a patent for the separation process and can reduce the discharge of waste sulfuric acid.

CN101633613A (2010-01-27) patent introduces the device and process for the continuous production of 2-ethylanthraquinone in a pipeline reactor. ) Benzoic acid does not achieve microscopic mixing in sulfuric acid solution, resulting in low yield. At the same time, the protectable basic parameters of jet mixing are not given in the patent requirements.

Luo et al. (Science and Technology Information, 2009, vol 19, 11-12) also disclosed the continuous process research on the ring-closing reaction of 2-(4-ethylbenzoyl)benzoic acid, and provided a suitable reaction process, but sulfuric acid It is firstly mixed with solid 2-(4-ethylbenzoyl)benzoic acid, and the ring-closing reaction temperature is high, the reaction time is short, and industrial manipulation is relatively difficult.

At present, most manufacturers at home and abroad use 2-(4-ethylbenzoyl)benzoic acid to obtain 2-ethylanthraquinone through drying, granulation, concentrated sulfuric acid dissolution, heating reaction, hydrolysis, extraction, distillation and other processes. The yield is 75-79%. The process is cumbersome, complex, labor-intensive, and low yield, and requires improvement in the production process.

Contents of the invention

The present invention overcomes the deficiencies existing in the prior art, and provides a kind of continuous, without drying, granulation, concentrated sulfuric acid dissolution and other processes, continuous 2-(4-alkylbenzene) with high product yield and stable quality A method for preparing 2-ethylanthraquinone by ring-closing reaction of acyl)benzoic acid.

The present invention is realized by following measures:

The preparation process of the 2-ethylanthraquinone of the present invention is completed by two-step reactions.

the

The first step uses AlCl3 as a catalyst to catalyze the Friedel-Crafts acylation reaction of phthalic anhydride and ethylbenzene to generate 2-(4-ethylbenzoyl)benzoic acid, and the second step 2-(4-ethylbenzene Formyl)benzoic acid is dehydrated and ring-closed in oleum to generate 2-ethylanthraquinone. The reaction of the first step belongs to the acylation reaction, and its patented technology is mature. This patent studies the second step. The fuming sulfuric acid used in the reaction has certain pollution to the environment. Therefore, the dehydration ring-closing reaction process of the present invention is shown in the accompanying drawings.

The method for preparing 2-ethylanthraquinone by continuous 2-(4-alkylbenzoyl)benzoic acid ring-closing reaction, the temperature is 140-180°C of liquid 2-(4-alkylbenzoyl)benzoic acid quality and room temperature The volume ratio of concentrated sulfuric acid is 1:1.5-1:2.5, mixed in the mixer, the mixing temperature is room temperature-100°C, the residence time of the mixture in the mixer is 1-10min, the mixer is connected in series with the stirring reactor, Carry out a closed-loop reaction, the temperature of the stirred reactor is 100-140 ° C, the residence time of the reaction material in the reactor is 5-30 minutes, the liquid after the reaction is directly hydrolyzed, extracted with benzene or toluene solvent, and 2-ethylanthraquinone is obtained after distillation .

The mixer is a stirring mixer, a jet mixer, a pipeline mixer, the stirring mixer is a mixer with impeller stirring, the jet mixer is a Venturi tube jet mixer, and the pipeline mixer is an industrial static mixer , so that the mixing of liquids reaches molecular-scale mixing.

The preferred temperature of the liquid 2-(4-alkylbenzoyl)benzoic acid is 130-180°C, and the preferred mixing temperature is room temperature-80°C.

The number of the stirred reactors in series is 1-5 reactors, preferably the number of the stirred reactors in series is 2-3.

In order to make 2-(4-alkylbenzoyl)benzoic acid reach molecular scale mixing in concentrated sulfuric acid as soon as possible, the larger the ratio, the better, but in order to control the output of waste acid, 2-(4-alkylbenzene The ratio of formyl)benzoic acid and concentrated sulfuric acid is suitable at 1:1.5-1:2.5, and the ratio increases, and the purity of 2-ethylanthraquinone increases. And because 2-(4-alkylbenzoyl)benzoic acid is solid at normal temperature, in order to be able to produce continuously, must keep liquid state, and this also is the core place of this patent. After the previous rectification process, it can directly enter the mixer for mixing, control the temperature of 2-(4-alkylbenzoyl)benzoic acid at 130-180°C, and keep the concentrated sulfuric acid at room temperature -80°C.

Mixers and reactors are either known or commercially available.

There are many types of mixers, such as stirring mixers, jet mixers, and pipeline mixers that use this reaction to mix. This patent prefers the agitating mixer with impeller agitation. This mixing method can make the reaction materials reach molecular scale mixing through turbulent crushing and molecular diffusion. The mixing temperature in the mixer is controlled too high, which increases side reactions.

The ring-closing reaction is a fast dehydration reaction, and the reaction temperature is not easy to be too high. If it is too high, it will produce by-products-sulfonates, which will reduce the yield of by-products. Therefore, the temperature of the stirring reaction zone is controlled at 100-140°C; the reaction time is also dehydration. The important factors of the reaction are too short raw materials to react incompletely, and too long 2-ethylanthraquinone sulfonation to reduce the yield, so the residence time of the reaction materials in the reactor is 5-30min. The reaction in this process is a series reaction of complex reactions. In order to improve the yield of the reaction, the plug-flow reactor is the best. Based on the above-mentioned viewpoint, this patent can reduce the back-mixing characteristics with the serial stirring reactor, so as to achieve the best reaction process.

Compared with the prior art, the present invention has the following advantages: the process is simple to operate, easy to control, reduces labor intensity, improves the working environment, reduces equipment investment, reduces the amount of waste acid, and the yield of the product is higher than that of the existing production process Improve 5-10%, good product quality.

Description of drawings

Fig. 1 is the process chart that the present invention prepares 2-ethylanthraquinone. the

Detailed ways

List 8 embodiments below, the present invention is further described, but the present invention is not limited to these embodiments.

Example 1

Add 6.0g/min 2-(4-alkylbenzoyl)benzoic acid at 160°C and 15ml/min concentrated sulfuric acid at room temperature into a 250ml stirring mixer and mix, and the liquid 2-(4-alkylbenzoyl) ) The ratio of benzoic acid and concentrated sulfuric acid is 1:2.5, the mixing temperature is controlled at 60°C, the mixture flows into the first stirred reactor in overflow mode, the reactor temperature is controlled at 120°C, the residence time is 5min, and then the Flow into the second stirred reactor, the residence time is 3min, the control reactor temperature is 125°C, and then flow into the third stirred reactor in overflow mode, the residence time is 3min, the control reactor temperature is 120°C ℃. The reaction liquid flowing out from the reactor directly enters the hydrolysis tank for hydrolysis, extracts with an equal amount of toluene, and the oil phase is washed with alkali, washed with water, and distilled to obtain 2-ethylanthraquinone with a yield of 80.2%.

Example 2

Add 5.0g/min 2-(4-alkylbenzoyl)benzoic acid at 180°C and 11ml/min concentrated sulfuric acid at room temperature into a 250ml stirring mixer and mix, and the liquid 2-(4-alkylbenzoyl) ) The ratio of benzoic acid and concentrated sulfuric acid is 1:2.2. Control the mixing temperature at 40°C, the mixture flows into the first stirred reactor in an overflow manner, control the reactor temperature at 110°C, and the residence time is 4min, and then flow into the second stirred reactor in an overflow manner, and stay The time is 3 minutes, the temperature of the reactor is controlled at 130°C, and then it flows into the third stirred reactor in overflow mode, the residence time is 1min, and the temperature of the reactor is controlled at 140°C. The reaction liquid flowing out from the reactor directly enters the hydrolysis tank for hydrolysis, and is extracted with an equal amount of toluene. The oil phase is washed with alkali, washed with water, and distilled to obtain 2-ethylanthraquinone with a yield of 78.1%.

Example 3

Add 4.0g/min 2-(4-alkylbenzoyl)benzoic acid at 140°C and 7.6ml/min concentrated sulfuric acid at 60°C to a 250ml stirring mixer and mix, and the liquid 2-(4-alkylbenzene The ratio of formyl)benzoic acid to concentrated sulfuric acid is 1:1.9. Control the mixing temperature at 50°C, the mixture flows into the first stirred reactor in an overflow manner, control the reactor temperature at 110°C, and the residence time is 5min, and then flow into the second stirred reactor in an overflow manner, and stay The time is 3 minutes, and the temperature of the reactor is controlled at 130°C. The reaction liquid flowing out from the reactor directly enters the hydrolysis tank for hydrolysis, extracts with an equal amount of toluene, and the oil phase is washed with alkali, washed with water, and distilled to obtain 2-ethylanthraquinone with a yield of 82.5%.

Example 4

Add 6.0g/min 2-(4-alkylbenzoyl)benzoic acid at 160°C and 15ml/min concentrated sulfuric acid at 60°C to a 250ml stirring mixer and mix, and the liquid 2-(4-alkylbenzoyl) The ratio of acyl)benzoic acid to concentrated sulfuric acid is 1:2.5. Control the mixing temperature at 80°C, the mixture flows into the first reactor in an overflow manner, control the reactor temperature at 120°C, and the residence time is 10min, and then flow into the second reactor in an overflow manner, the residence time is 12min, the temperature of the reactor was controlled at 125°C. The reaction liquid flowing out from the reactor directly enters the hydrolysis tank for hydrolysis, and is extracted with an equal amount of toluene. The oil phase is washed with alkali, washed with water, and distilled to obtain 2-ethylanthraquinone with a yield of 83.8%.

Example 5

Add 6.0g/min 2-(4-alkylbenzoyl)benzoic acid at 160°C and 15ml/min concentrated sulfuric acid at room temperature into a 250ml stirring mixer and mix, and the liquid 2-(4-alkylbenzoyl) ) The ratio of benzoic acid and concentrated sulfuric acid is 1:2.5. Control the mixing temperature at 60°C, the mixture flows into the first stirred reactor in an overflow manner, control the reactor temperature at 120°C, and the residence time is 3min, and then flow into the second stirred reactor in an overflow manner, and stay The time is 2 minutes, the temperature of the reactor is controlled at 130°C, and then it flows into the third stirred reactor in overflow mode, the residence time is 2min, and the temperature of the reactor is controlled at 130°C. Then it flows into the fourth reactor in an overflow manner, the residence time is 2min, and the temperature of the reactor is controlled at 125°C. Then it flows into the fifth reactor in an overflow manner, the residence time is 3min, and the temperature of the reactor is controlled at 120°C. The reaction liquid flowing out from the reactor directly enters the hydrolysis tank for hydrolysis, extracts with an equal amount of toluene, and the oil phase is washed with alkali, washed with water, and distilled to obtain 2-ethylanthraquinone with a yield of 85.3%.

Example 6

Add 6.0g/min 2-(4-alkylbenzoyl)benzoic acid at 160°C and 15ml/min concentrated sulfuric acid at 40°C to a 250ml stirring mixer and mix, and the liquid 2-(4-alkylbenzoyl) The ratio of acyl)benzoic acid to concentrated sulfuric acid is 1:2.5, the mixing temperature is controlled at 80°C, the mixture flows into the first stirred reactor in overflow mode, the reactor temperature is controlled at 120°C, and the residence time is 30min. The reaction liquid flowing out from the reactor directly enters the hydrolysis tank for hydrolysis, and is extracted with an equal amount of toluene. The oil phase is washed with alkali, washed with water, and distilled to obtain 2-ethylanthraquinone with a yield of 80.7%.

Example 7

Mix 6.0g/min 2-(4-alkylbenzoyl)benzoic acid at 160°C and 80°C concentrated sulfuric acid at 15ml/min in a Venturi jet mixer, The Reynolds number Re is 2500, and the ratio of liquid 2-(4-alkylbenzoyl)benzoic acid to concentrated sulfuric acid is 1:2.5. The mixture directly enters the first stirred reactor, the temperature of the reactor is controlled at 120°C, and the residence time is 5 minutes, and then flows into the second stirred reactor in an overflow mode, the residence time is 3 minutes, and the temperature of the reactor is controlled to be 125°C, and then flow into the third stirred reactor in an overflow manner, the residence time is 3min, and the temperature of the reactor is controlled at 120°C. The reaction liquid flowing out from the reactor directly enters the hydrolysis tank for hydrolysis, and is extracted with an equal amount of toluene. The oil phase is washed with alkali, washed with water, and distilled to obtain 2-ethylanthraquinone with a yield of 78.5%.

Example 8

Put 6.0g/min 2-(4-alkylbenzoyl)benzoic acid at 160°C and 15ml/min concentrated sulfuric acid at room temperature into a static mixer and mix, and the liquid 2-(4-alkylbenzoyl) The ratio of benzoic acid and concentrated sulfuric acid is 1:2.5. The mixing temperature is controlled at 60°C, the mixture directly enters the first stirred reactor, the temperature of the reactor is controlled at 120°C, the residence time is 5min, and then flows into the second stirred reactor in overflow mode, the residence time is 3min, Control the temperature of the reactor at 125°C, and then flow into the third reactor in an overflow manner, the residence time is 3min, and control the temperature of the reactor at 120°C. The reaction liquid flowing out from the reactor directly enters the hydrolysis tank for hydrolysis, extracts with an equal amount of toluene, and the oil phase is washed with alkali, washed with water, and distilled to obtain 2-ethylanthraquinone with a yield of 77.8%.

Claims (5)

1. The method for preparing 2-ethylanthraquinone by continuous 2-(4-alkylbenzoyl) benzoic acid ring-closure reaction, is characterized in that: the temperature is 140-180°C liquid 2-(4-alkylbenzoyl) The ratio of the mass of benzoic acid to the volume of concentrated sulfuric acid at room temperature is 1:1.5-1:2.5, mixed in a mixer, the mixing temperature is room temperature-100°C, the residence time of the mixture in the mixer is 1-10min, the mixer It is connected in series with a stirred reactor to perform a closed-loop reaction. The temperature of the stirred reactor is 100-140°C. The residence time of the reaction material in the reactor is 5-30 minutes. The liquid after the reaction is directly hydrolyzed, extracted with benzene or toluene solvent, and obtained after distillation. 2-Ethylanthraquinone. 2. continuous 2-(4-alkylbenzoyl) benzoic acid ring-closure reaction according to claim 1 prepares the method for 2-ethylanthraquinone, it is characterized in that: described mixer is stirring mixer, jet Mixer, pipeline mixer, stirring mixer is a mixer with impeller stirring, jet mixer is Venturi tube jet mixer, and pipeline mixer is an industrial static mixer, so that the mixing of liquids can reach the mixing of molecular scale. 3. continuous 2-(4-alkylbenzoyl) benzoic acid ring-closure reaction according to claim 1 prepares the method for 2-ethylanthraquinone, it is characterized in that: liquid 2-(4-alkylbenzoyl ) benzoic acid at 130-180°C, and the mixing temperature at room temperature -80°C. 4. the method for preparing 2-ethylanthraquinone by continuous 2-(4-alkylbenzoyl) benzoic acid ring-closure reaction according to claim 1, is characterized in that: the number of stirring reactors connected in series is 1-5 reactor. 5. according to claim 1 and 4 described continuous 2-(4-alkylbenzoyl) benzoic acid ring-closure reaction prepares the method for 2-ethylanthraquinone, it is characterized in that: the number of stirring reactors in series is 2- 3.

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