Co-production preparation method of nitryl-containing aromatic aldehyde and aromatic acid

Abstract

The invention relates to the technical field of preparation of pesticide chemical intermediates, and relates to a co-production preparation method of nitryl-containing aromatic aldehyde and aromatic acid. Comprising the following steps: 1, carrying out a chlorination reaction on a methyl aromatic compound and chlorine to synthesize a mixture A; 2, carrying out nitration reaction on the mixture A and nitric acid to synthesize a mixture B; step 3, carrying out hydrolysis reaction on the mixture B to obtain a mixture C; 4, the mixture C is subjected to alkali washing and layering, the upper layer is subjected to aftertreatment to obtain nitryl-containing aromatic aldehyde, and the lower layer is subjected to pH adjustment to obtain nitryl-containing aromatic acid. The method belongs to a continuous process, and is safe and efficient; rectification separation of benzyl dichloride and benzyl trichloride is not needed, so that the energy consumption is greatly reduced; the nitryl-containing aromatic acid produced in the method is also a key intermediate of a pesticide product saflufenacil, the two intermediates can be separated only through layering, the operation is simple, the overall yield is greatly improved, and the raw material utilization rate is high.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of pesticide chemical intermediates, in particular to the field of IPC B01J, and more specifically to a method for co-producing nitro-containing aromatic aldehydes and aromatic acids. Background Art

[0002] Nitro aromatic aldehydes are important chemical intermediates that can be used in the synthesis of pesticide products such as benzylpyridin and fluazifop. At present, the main synthesis method at home and abroad is to obtain the dichloro product by chlorination and distillation separation of toluene raw materials, and then nitrate and hydrolyze it. In this process, the separation of the dichloro product is difficult, the energy consumption is high, and the loss of dichloro is large, which results in low overall yield and high production cost.

[0003] CN 1944396A discloses a method for synthesizing o-nitrobenzoic acid by catalyzing the oxidation of o-nitrotoluene with oxygen using anhydrous methanol and methanol-benzene as solvents and metal phthalocyanine as a biomimetic catalyst in an alkaline medium; CN 1521153A discloses a method for synthesizing o-nitrobenzoic acid by catalyzing the oxidation of o-nitrotoluene with oxygen using chloroferric porphyrin as a biomimetic catalyst; CN103755520A discloses a method for producing benzyl alcohol, aldehyde and acid by oxidizing substituted toluene with air in a gas-liquid-solid multiple reaction separation synchronous reactor catalyzed by transition metal porphyrin. The above public reports have the problems of low yield, difficulty in separation and purification, etc., which limit their industrial application. Summary of the invention

[0004] The present invention provides a method for co-producing nitro-containing aromatic aldehydes and aromatic acids, the reaction formula of which is shown in Formula 1-3, and comprises the following steps:

[0005]

[0006] 3;

[0007] Step 1: chlorinating a methyl aromatic compound with chlorine to synthesize a mixture A;

[0008] Step 2: subjecting mixture A to nitration reaction with nitric acid and concentrated sulfuric acid to synthesize mixture B;

[0009] Step 3: subjecting mixture B to a hydrolysis reaction to obtain mixture C;

[0010] Step 4: extracting, alkali washing and layering the mixture C; the upper layer is post-treated to obtain a nitro-containing aromatic aldehyde; and the lower layer is pH-adjusted to obtain a nitro-containing aromatic acid.

[0011] The general structural formula of the methyl aromatic compound is shown in Formula 1: 1, wherein X includes one of F, Cl, Br, and H, and Y includes one of F, Cl, Br, and H.

[0012] Preferably, X comprises one of F, Cl and Br, and Y comprises one of F, Cl and Br.

[0013] The chlorination reaction is carried out in a microchannel reactor, and the nitration reaction is carried out in a tubular reactor.

[0014] The applicant has found that through post-treatments such as extraction, alkali washing, and layering, aromatic aldehydes containing substituents and aromatic acids containing substituents can be prepared at the same time, and aromatic aldehydes containing substituents with a content of ≥99% can be prepared in the oil phase, and aromatic acids containing substituents with a content of ≥99% can be prepared in the water phase. Separation can be achieved by layering only, the operation is simple, the overall yield is greatly improved, there is no loss of raw materials, and the economic value is relatively high.

[0015] The molar ratio of the methyl aromatic compound to chlorine is 1:(2-3).

[0016] Preferably, the molar ratio of the methyl aromatic compound to chlorine is 1:(2-2.2).

[0017] The step 2 specifically includes: mixing mixture A with a solvent, and performing a nitration reaction with nitric acid and concentrated sulfuric acid to synthesize mixture B; the solvent includes one of dichloromethane, 1,1-dichloroethane, and 1,2-dichloroethane.

[0018] Preferably, the solvent is one of dichloromethane and 1,2-dichloroethane.

[0019] The weight ratio of the solvent to the mixture A is (0.1-10):1.

[0020] Preferably, the weight ratio of the solvent to the mixture A is (0.1-2):1.

[0021] The mass concentration of the nitric acid is greater than 95%.

[0022] Preferably, the mass concentration of the nitric acid is >98%.

[0023] The temperature of the hydrolysis reaction is 60-100°C.

[0024] Preferably, the temperature of the hydrolysis reaction is 70-80°C.

[0025] The alkaline washing reagent includes one of sodium hydroxide, potassium hydroxide, sodium carbonate and sodium bicarbonate.

[0026] Preferably, the alkali washing agent includes one of sodium carbonate and sodium bicarbonate.

[0027] The pH was adjusted to 0-6.

[0028] Preferably, the pH is adjusted to 2-4.

[0029] Beneficial Effects

[0030] 1. The present invention is a continuous process, which is safe and efficient.

[0031] 2. The mixture A in the present invention does not need to be distilled and separated, so energy consumption and product loss are greatly reduced, the production cycle is shortened, and the yield is improved.

[0032] 3. The mixture C in the present invention is simple to separate and easy to operate, and the obtained purity is greater than 99%, which has a high economic utilization value.

[0033] 4. The final two products obtained by the reaction of the present invention have no raw material loss and an atomic utilization rate of 100%, which is in line with the concept of green chemistry.

[0034] 5. The present invention adopts microchannel chlorination and tubular nitration for continuous synthesis, which is safe and efficient, greatly reduces the safety risks of the two-step high-risk reactions of chlorination and nitration, and complies with the concept of intrinsic safety. DETAILED DESCRIPTION

[0035] Example 1

[0036] A method for co-producing nitro-containing aromatic aldehydes and aromatic acids comprises the following steps:

[0037] Step 1: 2-Chloro-4-fluorotoluene and liquid chlorine are introduced into the microchannel at a molar ratio of 1:2.2 for chlorination reaction. The reaction results in a total of 720g of mixture A, with dichlorobenzyl and trichlorobenzyl contents of 85.6wt% and 14.4wt%, respectively. The mixture A is divided into two (360g each), one of which is distilled to finally obtain 290g dichlorobenzyl (>99%), 49.2g trichlorobenzyl (>99%), and 20.8g of the remaining kettle residue, the main components of which are polymer and a small amount of trichlorobenzyl, with a yield loss of 5.8wt%; the other is directly synthesized in step 2.

[0038] Step 2: Add 0.5 times the mass of 1,2-dichloroethane solvent to the mixture in step 1, and introduce it into a tubular reactor with 98% nitric acid and concentrated sulfuric acid in a certain mass ratio to carry out nitration reaction to obtain a mixture B;

[0039] Step 3: hydrolyze the mixture B in step 2 at a temperature of about 75° C. to obtain a mixture C after the hydrolysis is completed;

[0040] Step 4: Add 1,2-dichloroethane to the mixture C of step 3 to extract the organic phase, add 1wt% sodium bicarbonate aqueous solution to the separated organic phase for alkali washing and separation, take the upper oil phase for desolventizing and crystallization post-treatment to obtain 279.5g of 2-chloro-4-fluorobenzaldehyde; take the lower aqueous phase, add 31wt% hydrochloric acid dropwise thereto, control the system pH to 2.0, stand and separate, and obtain 44.9g of 2-chloro-4-fluorobenzoic acid.

[0041] Example 2

[0042] A method for co-producing nitro-containing aromatic aldehydes and aromatic acids comprises the following steps:

[0043] Step 1: 2-chlorotoluene and liquid chlorine are introduced into the microchannel at a molar ratio of 1:2.3 for chlorination reaction. The reaction results in a total of 780g of mixture A, with dichlorobenzyl and trichlorobenzyl contents of 77.2wt% and 22.8wt%, respectively. The mixture A is divided into two (390g each), one of which is distilled to finally obtain 289.1g dichlorobenzyl (>99%) and 82.3g trichlorobenzyl (>99%), and the remaining kettle residue is 18.6g, the main components of which are polymer and a small amount of trichlorobenzyl, and the yield loss is 4.8wt%; the other is directly synthesized in step 2.

[0044] Step 2: Add 0.6 times the mass of dichloromethane solvent to the mixture in step 1, and introduce it into a tubular reactor with 98% nitric acid and concentrated sulfuric acid in a certain mass ratio to carry out nitration reaction to obtain a mixture B;

[0045] Step 3: hydrolyze the mixture B in step 2 at a temperature of about 70° C. to obtain a mixture C after the hydrolysis is completed;

[0046] Step 4: Add dichloromethane to the mixture C in step 3 to extract the organic phase, add 1wt% sodium carbonate aqueous solution to the separated organic phase for alkali washing and separation, take the upper oil phase for desolventizing and crystallization post-treatment to obtain 271.5g of 2-chlorobenzaldehyde; take the lower aqueous phase, add 31wt% hydrochloric acid dropwise thereto, control the system pH to 3.0, stand and separate, and obtain 76.3g of 2-chlorobenzoic acid.

[0047] Example 3

[0048] A method for co-producing nitro-containing aromatic aldehydes and aromatic acids comprises the following steps:

[0049] Step 1: 2-Fluoro-4-bromotoluene and liquid chlorine are introduced into the microchannel at a molar ratio of 1:2.2 for chlorination reaction. The reaction results in a total of 740g of mixture A, with dichlorobenzyl and trichlorobenzyl contents of 84.3wt% and 15.7wt%, respectively. The mixture A is divided into two (370g each), one of which is distilled to finally obtain 306.9g dichlorobenzyl (>99%) and 44.2g trichlorobenzyl (>99%), and the remaining kettle residue is 18.9g, the main components of which are polymer and a small amount of trichlorobenzyl, and the yield loss is 5.1wt%; the other is directly synthesized in step 2.

[0050] Step 2: Add 0.8 times the mass of dichloromethane solvent to the mixture in step 1, and introduce 98wt% nitric acid and concentrated sulfuric acid in a certain mass ratio into a tubular reactor for nitration reaction to obtain a mixture B;

[0051] Step 3: heating the mixture B in step 2 to hydrolyze at a temperature of about 80° C. to obtain a mixture C after the hydrolysis is completed;

[0052] Step 4: Add dichloromethane to the mixture C in step 3 to extract the organic phase, add 1wt% sodium carbonate aqueous solution to the layered organic phase for alkali washing and layering, take the upper oil phase for desolventizing and crystallization post-treatment to obtain 284.8g of 2-fluoro-4-bromobenzaldehyde; take the lower aqueous phase, add 31wt% hydrochloric acid dropwise thereto, control the system pH to 1.0, stand and layer, and obtain 51.2g of 2-fluoro-4-bromobenzoic acid.

[0053] Performance Testing Methods

[0054] The aromatic aldehydes and aromatic acids prepared in the examples were subjected to HPLC purity tests, and the test data are listed in Table 1.

[0055] Performance test data

[0056] Table 1

[0057] Aromatic aldehydes Aromatic acid Example 1 99.1％ 99.3％ Example 2 99.4％ 99.2％ Example 3 99.3％ 99.1％

Claims

1. A method for co-producing nitro-containing aromatic aldehydes and aromatic acids, characterized in that: The following steps are involved: Step 1: chlorinating a methyl aromatic compound with chlorine to synthesize a mixture A; Step 2: subjecting mixture A to nitration reaction with nitric acid and concentrated sulfuric acid to synthesize mixture B; Step 3: subjecting mixture B to a hydrolysis reaction to obtain mixture C; Step 4: extracting, alkali washing and layering the mixture C; the upper layer is post-treated to obtain a nitro-containing aromatic aldehyde; and the lower layer is pH-adjusted to obtain a nitro-containing aromatic acid.

2. The method for co-producing nitro-containing aromatic aldehydes and aromatic acids according to claim 1, characterized in that: The general structural formula of the methyl aromatic compound is shown in Formula 1: Wherein, X includes one of F, Cl, Br, and H, and X includes one of F, Cl, Br, and H.

3. The method for co-producing nitro-containing aromatic aldehydes and aromatic acids according to claim 2, characterized in that: The chlorination reaction is carried out in a microchannel reactor, and the nitration reaction is carried out in a tubular reactor.

4. The method for co-producing nitro-containing aromatic aldehydes and aromatic acids according to claim 1 or 3, characterized in that: The molar ratio of the methyl aromatic compound to chlorine is 1:(2-3).

5. The method for co-producing nitro-containing aromatic aldehydes and aromatic acids according to claim 4, characterized in that: The molar ratio of the methyl aromatic compound to chlorine is 1:(2-2.2).

6. The method for co-producing nitro-containing aromatic aldehydes and aromatic acids according to claim 5, characterized in that: The step 2 specifically includes: mixing mixture A with a solvent, and performing a nitration reaction with nitric acid to synthesize mixture B; the solvent includes one of dichloromethane, 1,1-dichloroethane, and 1,2-dichloroethane.

7. The method for co-producing nitro-containing aromatic aldehydes and aromatic acids according to claim 6, characterized in that: The weight ratio of the solvent to the mixture A is (0.1-10):

1.

8. The method for co-producing nitro-containing aromatic aldehydes and aromatic acids according to claim 1 or 7, characterized in that: The temperature of the hydrolysis reaction is 60-100°C.

9. The method for co-producing nitro-containing aromatic aldehydes and aromatic acids according to claim 8, characterized in that: The alkaline washing reagent includes one of sodium hydroxide, potassium hydroxide, sodium carbonate and sodium bicarbonate.

10. The method for co-producing nitro-containing aromatic aldehydes and aromatic acids according to claim 9, characterized in that: The pH was adjusted to 0-6.

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