A process for the preparation of phthaloylbenzene

Abstract

The present application provides a method for preparing m-dibenzoic acid. The method comprises the following steps: after m-dialkylbenzene is alkali washed with an oxygen-containing gas, the m-dialkylbenzene is contacted and reacted under the condition of a transition metal salt catalyst and a polyethylene glycol cocatalyst to generate a m-dibenzoic acid compound. When m-dibenzoic acid is prepared by oxidizing m-dialkylbenzene, the process is simple, the reaction condition is mild, the raw material is easy to obtain, and the method is suitable for industrial production.

Description

TECHNICAL FIELD

[0001] The present application relates to a method for preparing m-dibenzoic acid, belonging to the technical field of organic synthesis. BACKGROUND

[0002] M-dibenzoic acid is an important intermediate in organic synthesis, and has a broad application prospect in metal organic chemistry, pesticides, polymer materials and medicines. M-dibenzoic acid has a certain market demand, and its synthesis method is concerned by scholars.

[0003] There are mainly the following methods for preparing m-dibenzoic acid: (1) using m-diethylbenzene as raw material, which is oxidized by an oxidizing agent to prepare m-dibenzoic acid (Gazzetta Chimica Italiana, 1947, 77, 607-610). This method uses heavy metals as oxidizing agent, the production cost is high, and the reaction yield is only about 80%, which is not suitable for industrialized batch production; (2) using 1,3-dibromobenzene as raw material, reacting under the action of tert-butyl lithium to obtain m-dibenzoic acid compounds (Journal of the American Chemical Society, 1991, 113, 4109-4120). Tert-butyl lithium is highly flammable, and the operation process must be cautious, which greatly increases the risk of the reaction. The final product separation method is still silica gel column chromatography, and the yield of the target product is less than 20%; (3) patent CN102643181A discloses a method for synthesizing m-dibenzoic acid using isophthaloyl chloride as raw material. The method is to condense the raw material under the action of strong base to obtain ester derivatives; then the ester derivatives are decarboxylated under the action of strong acid to obtain m-dibenzoic acid compounds; the reaction liquid needs to be extracted and distilled, and finally m-dibenzoic acid is prepared. This process needs to use strong base and strong acid, the reaction requires high equipment material quality, and the reaction raw material is difficult to obtain; (4) patent CA102643181A uses isophthaldehyde as raw material, first reacts with Grignard reagent to generate corresponding alcohol compounds, and then the alcohol compounds are oxidized by des-martin high iodine to generate m-dibenzoic acid. This process uses Grignard reagent, which has certain risk in production, and the oxidizing agent is expensive, and the raw material aromatic aldehyde compound is difficult to obtain.

[0004] The method for converting isopropyl aromatic compounds into acyl aromatic compounds has been reported. Literature uses ferrous chloride as catalyst to convert isopropylbenzene into phenylacetone, which needs two-step reaction. For m-diisopropylbenzene, the simple use of transition metal salt catalysis has low yield and produces more benzyl alcohol impurities. How to change the reaction conditions and improve the reaction yield has become a big problem.

[0005] In combination with the above, the current preparation process of m-dibenzoic acid generally has the problems of complex reaction conditions, difficult to obtain raw materials, low yield, and low production efficiency in scale-up production, which need to be solved. SUMMARY

[0006] One of the purposes of the present application is to provide a method for preparing m-dibenzoic acid, which has the advantages of low cost, easy availability of raw materials, mild reaction, etc., and can be produced on a large scale.

[0007] To achieve the above-mentioned purposes, the technical solutions adopted by the present application are as follows:

[0008] A method for preparing a m-dibenzoic acid compound, comprising the following steps: after alkali washing of m-dialkylbenzene with an oxygen-containing gas, under the condition of a transition metal salt catalyst and a polyethylene glycol cocatalyst, the m-dialkylbenzene is subjected to contact reaction to generate the m-dibenzoic acid compound.

[0009] The reaction is shown as follows:

[0010]

[0011] In the formula, R is a linear or branched alkyl group with 1-8 carbon atoms.

[0012] In an embodiment of the present application, the m-dibenzoic acid compound prepared by the method has the structure of:

[0013]

[0014] In the formula, R is a linear or branched alkyl group with 1-8 carbon atoms.

[0015] In an embodiment of the present application, the m-dialkylbenzene has the structure of:

[0016]

[0017] In the formula, R is a linear or branched alkyl group with 1-8 carbon atoms.

[0018] In an embodiment of the present application, the O2 content in the oxygen-containing gas is 5-30 vol%.

[0019] In an embodiment of the present application, the inlet rate of the oxygen-containing gas is 5-100 mL / min.

[0020] In an embodiment of the present application, the alkali used in the alkali washing is a Lewis base, preferably comprising one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and magnesium hydroxide; preferably, the concentration of the alkali is 0.05-5 wt%.

[0021] In an embodiment of the present application, the amount of the alkali solution added during the alkali washing of the oil phase is 1-10 wt% of the mass of the m-dialkylbenzene oil phase.

[0022] In one embodiment of the present application, the transition metal salt catalyst is a salt of one or more of sulfate, nitrate, carbonate, phosphate, chloride of a transition metal element; preferably, the catalyst is added in an amount of 0.02-0.2 times the mass of the m-dialkylbenzene.

[0023] In one embodiment of the present application, the polyethylene glycol has a molecular weight of 400-5000; preferably, the polyethylene glycol is added in an amount of 0.01-0.5 times the mass of the m-dialkylbenzene.

[0024] In one embodiment of the present application, the oxidation reactor used in the reaction is a bubble column or a stirred tank reactor.

[0025] In one embodiment of the present application, the reaction is carried out at a temperature of 40-100℃, a pressure of 1-20 barg, and for a time of 2-20 h.

[0026] Another object of the present application is to provide a m-diacylbenzene compound.

[0027] The m-diacylbenzene compound is the compound prepared by the above method, and the compound is:

[0028]

[0029] wherein R is a linear or branched alkyl group having 1-8 carbon atoms.

[0030] Compared with the prior art, the present application has the following advantages:

[0031] (1) The m-dialkylbenzene is used as the raw material, which is easy to obtain and can be directly obtained by isopropylbenzene alkylation;

[0032] (2) The cocatalyst strengthens the mass transfer, reduces the generation of by-products, and improves the reaction selectivity;

[0033] (3) The by-product methanol generated after the reaction can be recycled as the solvent. DETAILED DESCRIPTION

[0034] The present application is further described below by means of specific examples, which are only used to illustrate the present application and do not limit the scope of the present application.

[0035] I. Information of main raw materials

[0036] m-diisopropylbenzene, purity > 99%, Jiangsu Changqing Tree Co., Ltd.;

[0037] 1,3-bis(3-pentyl)benzene, purity > 98%, Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0038] 1,3-bis(4-nonyl)benzene, purity > 98%, Shanghai Aldrin Biochemical Technology Co., Ltd.;

[0039] Polyethylene glycol, reagent grade, San Chemical Technology (Shanghai) Co., Ltd.;

[0040] Sodium hydroxide, purity > 99%, Beijing Inokai Co., Ltd.;

[0041] Sodium carbonate, purity > 99%, Beijing Inokai Co., Ltd.;

[0042] Potassium hydroxide, purity > 99%, Beijing Inokai Co., Ltd.;

[0043] Potassium carbonate, purity > 99%, Beijing Inokai Co., Ltd.;

[0044] Iron sulfate, purity > 99%, Beijing Inokai Co., Ltd.;

[0045] Ferric chloride, purity > 99%, Beijing Inokai Co., Ltd.;

[0046] Copper sulfate, purity > 99%, Beijing Inokai Co., Ltd.;

[0047] Zinc nitrate, purity > 99%, Beijing Inokai Co., Ltd.;

[0048] Compressed air, oxygen content > 21%, obtained by air compressor;

[0049] II. Main analysis instrument

[0050] (1) High performance liquid chromatograph

[0051] The present application uses high performance liquid chromatography to analyze reaction conversion rate and selectivity, and the chromatographic analysis conditions are as follows: instrument model: LC-6A high performance liquid chromatograph (Shimadzu)

[0052] Analysis column: CLC-SIL 150*6.0mm (Shimadzu)

[0053] Preparation column: Zorbax SIL 250*9.4mm (column bang)

[0054] Mobile phase: diethyl ether: methanol: isopropanol: isopropyl cyclohexane (60-90℃) = 15:3:3:60 (v / v) Flow rate: 0.7ml / min

[0055] Column temperature: room temperature

[0056] UV detector (Shimadzu SPD-6AV UV-visible spectrophotometer detector) wavelength: 235nm;

[0057] (2) Fourier infrared spectrometer

[0058] The present application uses infrared spectrum to qualitatively analyze the target product, and the analysis conditions are as follows:

[0059] Instrument model: Nexus 670 infrared spectrometer of Nicolet Company, USA

[0060] Test mode: reflection mode.

[0061] Example 1

[0062] In a 100L high-pressure reactor, 10L of 0.05wt% sodium hydroxide solution was added, and oxygen-containing gas (oxygen content 5vol%) was injected to 10barg, and stirred for 1h. Air was filled into an air tank for standby, and the pressure was 8barg. 1000g of m-diisopropylbenzene and 100g of 0.05wt% sodium hydroxide solution were added into a 3L high-pressure reactor, and stirred for 1h to prepare the raw material.

[0063] Iron sulfate was continuously added to the 3L high-pressure reactor, and the addition amount was 0.2 times the mass of m-diisopropylbenzene. Polyethylene glycol with a molecular weight of 400 was added, and the addition amount was 0.5 times the mass of m-diisopropylbenzene. After being sealed, the temperature was raised to 40℃, and the oxygen-containing gas in the air tank was continuously introduced, and the gas inlet rate was controlled at 100mL / min, and the pressure was controlled at 1barg by a back pressure valve. After 20h of reaction, the reaction liquid was cooled to room temperature, and the stirring and gas inlet were stopped, and oil-water separation was carried out. The molar amount of m-dialkylbenzene and m-diacetylbenzene in the oil phase was determined by HPLC method, and the structure of the main product was analyzed by infrared spectrum. By comparing the infrared spectra of the raw material and the product, it was found that a strong absorption peak appeared at 1684cm -1 in the product spectrum, which was a carbonyl (C=O) absorption peak, indicating that the main product of the reaction was m-diacetylbenzene. HPLC analysis confirmed that the conversion rate of m-diisopropylbenzene was 91.2%, and the yield of m-diacetylbenzene was 90.6%.

[0064] Example 2

[0065] In a 100L high-pressure reactor, 10L of 0.1wt% potassium hydroxide solution was added, and oxygen-containing gas (oxygen content 10vol%) was injected to 10barg, and stirred for 1h. Air was filled into an air tank for standby, and the pressure was 8barg. 1000g of 1,3-bis(3-pentyl)benzene and 50g of 0.1wt% potassium hydroxide solution were added into a 3L high-pressure reactor, and stirred for 1h to prepare the raw material.

[0066] Continue to add iron sulfate to the 3L high-pressure reactor, the amount of addition is 0.1 times the mass of 1,3-bis(3-pentyl)benzene; add polyethylene glycol with a molecular weight of 400, the amount of addition is 0.5 times the mass of 1,3-bis(3-pentyl)benzene. Close, heat to 60℃, continuously introduce the oxygen-containing gas in the air storage tank, control the air inlet rate to be 80 mL / min, and control the pressure to be 3 barg through the back pressure valve. After 8h of reaction, cool the reaction liquid to room temperature, stop stirring and air inlet, and perform oil-water separation, and the oil phase is determined by HPLC method to determine the molar amount of meta-dialkylbenzene and meta-diacylbenzene. It is confirmed by analysis that the conversion rate of 1,3-bis(3-pentyl)benzene is 96.5%, and the yield of meta-dipropionylbenzene is 96.2%.

[0067] Example 3

[0068] In a 100L high-pressure reactor, 10L of 0.5wt% sodium carbonate solution, flush the air storage tank with air containing oxygen (oxygen content 15vol%) to 10barg, stir for 1h, and fill the air into the air storage tank for standby, pressure 8barg; 1000g of 1,3-bis(4-nonyl)benzene and 40g of 0.5wt% sodium carbonate solution are put into a 3L high-pressure reactor, stirred for 1h, and used as raw material for standby.

[0069] Continue to add iron sulfate to the 3L high-pressure reactor, the amount of addition is 0.1 times the mass of 1,3-bis(3-pentyl)benzene; add polyethylene glycol with a molecular weight of 400, the amount of addition is 0.5 times the mass of 1,3-bis(3-pentyl)benzene. Close, heat to 60℃, continuously introduce the oxygen-containing gas in the air storage tank, control the air inlet rate to be 80 mL / min, and control the pressure to be 3 barg through the back pressure valve. After 8h of reaction, cool the reaction liquid to room temperature, stop stirring and air inlet, and perform oil-water separation, and the oil phase is determined by HPLC method to determine the molar amount of meta-dialkylbenzene and meta-diacylbenzene. It is confirmed by analysis that the conversion rate of 1,3-bis(3-pentyl)benzene is 96.5%, and the yield of meta-dipropionylbenzene is 96.2%.

[0070] Example 4

[0071] In a 100L high-pressure reactor, 10L of 1wt% sodium carbonate solution, flush the air storage tank with air (oxygen content 21vol%) to 10barg, stir for 1h, and fill the air into the air storage tank for standby, pressure 8barg; 1000g of 1,3-bis(4-nonyl)benzene and 40g of 0.5wt% sodium carbonate solution are put into a 3L high-pressure reactor, stirred for 1h, and used as raw material for standby.

[0072] Continue to add ferric chloride to the 3L high-pressure reactor, the amount of addition is 0.05 times the mass of m-diisopropylbenzene; add polyethylene glycol with a molecular weight of 1000, the amount of addition is 0.2 times the mass of m-diisobutylbenzene. Close, heat to 100℃, continuously introduce air in the air tank, control the air inlet rate to be 20mL / min, control the pressure to be 3barg through the back pressure valve. After 2h of reaction, cool the reaction liquid to room temperature, stop stirring and air inlet, separate oil and water, and determine the molar amount of m-dialkylbenzene and m-diacylbenzene by HPLC method. It is confirmed by analysis that the conversion rate of m-diisopropylbenzene is 99.3%, and the yield of m-diacylbenzene is 94.5%.

[0073] Example 5

[0074] In a 100L high-pressure reactor, 10L of 5wt% sodium hydroxide solution, air containing oxygen (oxygen content 30vol%) in the air tank to 10barg, stirring 1h, air filled in the air tank for standby, pressure 8barg; 1000g of m-diisopropylbenzene and 10g of 5wt% sodium hydroxide solution were put into a 3L high-pressure reactor, stirred for 1h, and used as raw material for standby.

[0075] Continue to add copper sulfate to the 3L high-pressure reactor, the amount of addition is 0.02 times the mass of m-diisopropylbenzene; add polyethylene glycol with a molecular weight of 2000, the amount of addition is 0.1 times the mass of m-diisobutylbenzene. Close, heat to 60℃, continuously introduce air in the air tank, control the air inlet rate to be 5mL / min, control the pressure to be 3barg through the back pressure valve. After 8h of reaction, cool the reaction liquid to room temperature, stop stirring and air inlet, separate oil and water, and determine the molar amount of m-dialkylbenzene and m-diacylbenzene by HPLC method. It is confirmed by analysis that the conversion rate of m-diisopentylbenzene is 99.5%, and the yield of m-dibutyrylbenzene is 92.1%.

[0076] Example 6

[0077] In a 100L high-pressure reactor, 10L of 5wt% sodium hydroxide solution, air containing oxygen (oxygen content 30vol%) in the air tank to 10barg, stirring 1h, air filled in the air tank for standby, pressure 8barg; 1000g of m-diisopropylbenzene and 10g of 5wt% sodium hydroxide solution were put into a 3L high-pressure reactor, stirred for 1h, and used as raw material for standby.

[0078] The zinc nitrate was continuously added to the 3 L autoclave, and the amount of addition was 0.05 times the mass of the m-diisopropylbenzene; the polyethylene glycol with a molecular weight of 4000 was added, and the amount of addition was 0.02 times the mass of the m-diisobutylbenzene. After being closed, the temperature was raised to 60°C, and the air in the air tank was continuously introduced at a rate of 20 mL / min, and the pressure was controlled at 3 barg by a back pressure valve. After 8 h of reaction, the reaction liquid was cooled to room temperature, the stirring and air introduction were stopped, oil-water separation was performed, and the molar amount of m-diarylalkane and m-diacylbenzene in the oil phase was determined by HPLC. It was confirmed by analysis that the conversion rate of m-diisopropylbenzene was 99.6%, and the yield of m-diacylbenzene was 91.8%.

[0079] Example 7

[0080] In a 2000 L autoclave, 200 L of 1 wt% sodium hydroxide solution was used to flush the air (oxygen content 21 vol%) in the air tank to 10 barg, and the air was stirred for 1 h. The air in the air tank was filled for standby, and the pressure was 8 barg. 20 kg of m-diisopropylbenzene and 600 g of 1 wt% sodium hydroxide solution were added to the 60 L autoclave, and the liquid in the autoclave was transferred to the 60 L bubble column as a raw material for standby.

[0081] The iron sulfate was continuously added to the bubble column, and the amount of addition was 0.05 times the mass of the m-diisopropylbenzene; the polyethylene glycol with a molecular weight of 5000 was added, and the amount of addition was 0.01 times the mass of the m-diisobutylbenzene. After being closed, the temperature was raised to 60°C, and the air in the air tank was continuously introduced at a rate of 20 mL / min, and the pressure was controlled at 3 barg by a back pressure valve. After 10 h of reaction, the reaction liquid was cooled to room temperature, the stirring and air introduction were stopped, oil-water separation was performed, and the molar amount of m-diarylalkane and m-diacylbenzene in the oil phase was determined by HPLC. It was confirmed by analysis that the conversion rate of m-diisopropylbenzene was 98.5%, and the yield of m-diacylbenzene was 96.8%.

[0082] Example 8

[0083] In a 2000 L autoclave, 200 L of 1 wt% sodium hydroxide solution was used to flush the air (oxygen content 21 vol%) in the air tank to 10 barg, and the air was stirred for 1 h. The air in the air tank was filled for standby, and the pressure was 8 barg. 20 kg of m-diisopropylbenzene and 600 g of 1 wt% sodium hydroxide solution were added to the 60 L autoclave, and the liquid in the autoclave was transferred to the 60 L bubble column as a raw material for standby.

[0084] Continue to add ferric sulfate to the 60L high-pressure reactor, the amount of addition is 0.05 times the mass of m-diisopropylbenzene; add polyethylene glycol, the molecular weight is 5000, the amount of addition is 0.01 times the mass of m-diisobutylbenzene. Close, heat to 60℃, continuously pass in the air in the air storage tank, control the air inlet rate to be 20mL / min, control the pressure to be 3barg through the back pressure valve. After 10h of reaction, cool the reaction liquid to room temperature, stop stirring and air inlet, carry out oil-water separation, and the oil phase is determined by HPLC method. It is confirmed by analysis that the conversion rate of m-diisopropylbenzene is 99.5%, and the yield of m-diacylbenzene is 97.1%.

[0085] Comparative Example 1

[0086] This comparative example prepares m-diacylbenzene according to the same conditions as Example 8, the only difference is that polyethylene glycol is not added. After the reaction, oil-water separation is carried out, and it is confirmed by analysis that the conversion rate of m-diisopropylbenzene is 83.6%, and the yield of m-diacylbenzene is 13.5%.

[0087] Comparative Example 2

[0088] This comparative example prepares m-diacylbenzene according to the same conditions as Example 8, the only difference is that the reaction raw material m-diisopropylbenzene and air are not alkali washed. It is confirmed by analysis that the conversion rate of m-diisopropylbenzene is 73.5%, and the yield of m-diacylbenzene is 43.8%.

[0089] From the above test results, it can be seen that in the process of preparing m-diacylbenzene by reacting m-diisopropylbenzene with oxygen in the present application, the reaction has high atomic economy and mild reaction conditions.

[0090] The above is only the preferred embodiment of the present application, it should be pointed out that for the ordinary skilled in the art, without departing from the method of the present application, a number of improvements and supplements can also be made, these improvements and supplements should also be considered as the protection scope of the present application.

Claims

1. A process for preparing an anthrarobenzene compound, characterized by, The method comprises the following steps: after the m-dialkylbenzene is subjected to alkali washing with an oxygen-containing gas, the m-dialkylbenzene is subjected to contact reaction under the condition of a transition metal salt catalyst and a polyethylene glycol cocatalyst to generate a m-diacylbenzene-containing compound; The structure of the m-dialkylbenzene is as follows: The R group is a linear alkyl group with 1-8 carbon atoms. The structure of the m-diacylbenzene-containing compound is as follows: The R group is a linear alkyl group with 1-8 carbon atoms.

2. The method of claim 1, wherein, The O2 content in the oxygen-containing gas is 5-30 vol %. And / or, the feeding rate of the oxygen-containing gas is 5-100 mL / min.

3. The method according to claim 1 or 2, characterized in that, The alkali used in the alkali washing is a Lewis base. And / or, the amount of the alkali liquor added in the alkali washing is 1-10 wt % of the mass of the m-dialkylbenzene oil phase.

4. The method of claim 3, wherein, The alkali used in the alkali washing comprises one or more of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate and magnesium hydroxide. The concentration of the alkali is 0.05-5 wt %.

5. The method according to claim 1 or 2, characterized in that, The transition metal salt catalyst is a salt formed by one or more of sulfate, nitrate, carbonate, phosphate and chloride of a transition metal element. And / or, the molecular weight of the polyethylene glycol is 400-5000.

6. The method of claim 5, wherein, The addition amount of the catalyst is 0.02-0.2 times of the mass of the m-dialkylbenzene. The addition amount of the polyethylene glycol is 0.01-0.5 times of the mass of the m-dialkylbenzene.

7. The method according to claim 1 or 2, characterized in that, The oxidation reactor used in the reaction is a bubble column or a stirred tank reactor. And / or, the temperature of the reaction is 40-100℃, the reaction pressure is 1-20 barg, and the reaction time is 2-20 h.

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