Method for co-producing quinoline acyl chloride and 2-substituted acetyl chloride from trichloromethyl quinoline and 2-substituted acetic acid

Abstract

The invention discloses a method for co-producing quinoline acyl chloride and 2-substituted acetyl chloride from trichloromethyl quinoline and 2-substituted acetic acid, which comprises the following steps: reacting trichloromethyl quinoline and 2-substituted acetic acid as raw materials in a solvent under the action of a catalyst, and rectifying to obtain the quinoline acyl chloride and 2-substituted acetyl chloride. According to the co-production method, the two compounds can be obtained at one time without respective acylating chlorination, the reaction steps are few, the reaction time is short, the production efficiency is high, a large amount of acylating reagents are prevented from being used in the production process, toxic and harmful by-products are not generated, and the environmental pollution is reduced. The invention also discloses a novel method for preparing the quinoline carboxylic acid herbicide from quinoline acyl chloride through hydrolysis, the method is low in cost, mild in condition and easy to operate, and the product yield reaches 98% or above.

Description

Technical Field

[0001] The present invention belongs to the field of fine chemical industry, and particularly relates to a method for co-producing quinoline acyl chloride and 2-substituted acetyl chloride from trichloromethyl quinoline and 2-substituted acetic acid. Background Art

[0002] Quinoline acyl chloride is a key intermediate for synthesizing quinoline carboxylic acid herbicides V and V'. Quinoline carboxylic acid herbicide V, with the chemical name of 3,7-dichloro-8-quinoline carboxylic acid, is a new type of herbicide developed by BASF (Badische Anilin-&Soda-Fabrik), and its trade names include Fast Kill Barnyard Grass, Ke Bailling, etc. It can effectively control weeds such as barnyard grass, monochoria vaginalis, green foxtail, water dropwort, etc. in paddy fields, especially has a significant effect on barnyard grass, is safe for crops, and the application time is not restricted by the growth of weeds. Quinoline carboxylic acid herbicide V', with the chemical name of 2-(3,7-dichloroquinolin-8-yl)carbonyl-cyclohexane-1,3-dione, is a new type of herbicidal compound with independent intellectual property rights developed by Beijing Fagaiyin Technology Co., Ltd. It is a herbicide with a dual action mechanism, and simultaneously has soil and foliar treatment activities. It has good effects on barnyard grass, crabgrass, false loosestrife, eclipta prostrata, etc. in paddy fields, and is outstanding in controlling barnyard grass resistant to penoxsulam. It has the advantages of fast action speed, broad herbicidal spectrum, high safety, etc. The structural formulas of quinoline carboxylic acid herbicides V and V' are as follows:

[0003]

[0004] As an extremely important acylating agent, chloroacylating agent, and cycloacylating agent in organic synthesis, 2-substituted acetyl chloride is widely used in the fields of auxiliaries, insecticides, herbicides, and pharmaceutical synthesis.

[0005] Currently, the methods for producing quinoline acyl chloride and 2-substituted acetyl chloride mainly rely on the separate acyl chlorination of quinoline carboxylic acid and 2-substituted acetic acid, which requires a large amount of acylating reagents. Not only the cost is relatively high, but also the use of acylating reagents and the discharge of waste cause serious pollution to the environment. Summary of the Invention

[0006] In view of this, the purpose of the present invention is to provide a process method that can simultaneously produce quinoline acyl chloride and 2-substituted acetyl chloride without using acylating reagents, so as to improve atom economy and environmental friendliness and reduce the industrial production cost.

[0007] To achieve the above purpose, the present invention adopts the following technical solutions:

[0008] The first aspect of the present invention provides a method for co-producing quinoline acyl chloride and 2-substituted acetyl chloride from trichloromethylquinoline and 2-substituted acetic acid. The method uses trichloromethylquinoline shown in Formula I and 2-substituted acetic acid shown in Formula II as raw materials, reacts in a solvent under the action of a catalyst, and then obtains quinoline acyl chloride shown in Formula III and 2-substituted acetyl chloride shown in Formula IV through rectification. The reaction equation is as follows:

[0009]

[0010] Among them, R 1 、R 2 、R 3 are independently selected from any one of H, halogen, C1-C6 alkyl, substituted or unsubstituted phenyl, nitro, hydroxyl, and cyano.

[0011] Preferably, the R 1 、R 2 、R 3 are selected from any one of the substituent combinations shown in Table 1.

[0012] Table 1

[0013]

[0014]

[0015] Preferably, in the reaction, the molar ratio of the trichloromethylquinoline shown in Formula I to the catalyst is 10-1000:1; the reaction temperature is 50-200 °C, and the reaction time is 1-6 h.

[0016] Preferably, the molar ratio of the trichloromethylquinoline shown in Formula I to the catalyst is 100-500:1; the reaction temperature is 100-160 °C, and the reaction time is 2-3 h.

[0017] Preferably, the catalyst is selected from one or more of Lewis acids, inorganic acids, organic acids, acidic ionic liquids, molecular sieves, and zeolites.

[0018] Preferably, the Lewis acid is at least one of AlCl3, FeCl3, ZnCl2, SnCl4, BF3, NbCl5, Al2O3, ZnO2, FeO, Fe2O3, Fe3O4, SnO, and SnO2.

[0019] Preferably, the inorganic acid is at least one of sulfuric acid, phosphoric acid, nitric acid, hydrochloric acid, carbonic acid, boric acid, fuming sulfuric acid, sulfur trioxide, hydrofluoric acid, hydrobromic acid, hydroiodic acid, hypochlorous acid, hypobromous acid, perchloric acid, and perbromic acid.

[0020] Preferably, the organic acid is at least one of acetic acid, formic acid, propionic acid, acrylic acid, trifluoroacetic acid, trifluoromethanesulfonic acid, methanesulfonic acid, chlorosulfonic acid, isopropyl acid, butyric acid, tert-butyric acid, isobutyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, fruit acid, lactic acid, benzenesulfonic acid, benzoic acid, phenylacetic acid, p-toluenesulfonic acid, maleic acid, succinic acid, and oxalic acid.

[0021] Preferably, the solvent is selected from one or more of dichloromethane, dichloroethane, hexane, pentane, ethanol, methanol, isopropanol, n-butanol, tert-butanol, pentanol, dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, diethylene glycol dimethyl ether, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, chlorobenzene, chloroform, carbon tetrachloride, 4-chlorobenzotrifluoride, 3,4,5-trichlorobenzotrifluoride, 1,3,5-trichloromethylbenzene, 1,3,5-trifluoromethylbenzene, toluene, and benzene.

[0022] Preferably, the quinoline-3-carbonitrile shown in formula I is prepared by side-chain chlorination reaction of the methylquinoline shown in formula VI with an initiator in a solvent, and the reaction equation is:

[0023]

[0024] Preferably, in the side-chain chlorination reaction, the molar ratio of the methylquinoline shown in formula VI to the initiator is 50-200:1; the reaction temperature is 100-230 °C, and the reaction time is 1-10 h.

[0025] Preferably, the molar ratio of the methylquinoline shown in formula VI to the initiator is 80-120:1; the reaction temperature is 150-180 °C, and the reaction time is 2-6 h.

[0026] Preferably, the initiator is selected from one or more of azo initiators, peroxide initiators, and persulfate initiators.

[0027] Preferably, the azo initiator is at least one of azobisisobutyronitrile and azobisisoheptonitrile.

[0028] Preferably, the peroxide initiator is at least one of benzoyl peroxide, lauroyl peroxide, cumene hydroperoxide, tert-butyl hydroperoxide, dicumyl peroxide, tert-butyl peroxybenzoate, tert-butyl peroxypivalate, methyl ethyl ketone peroxide, and cyclohexanone peroxide.

[0029] Preferably, the persulfate initiator is at least one of potassium persulfate, sodium persulfate, and ammonium persulfate.

[0030] Preferably, in the side-chain chlorination reaction, the solvent is selected from one or more of ortho-dichlorobenzene, meta-dichlorobenzene, para-dichlorobenzene, chlorobenzene, chloroform, carbon tetrachloride, 4-chlorobenzotrifluoride, 3,4,5-trichlorobenzotrifluoride, 1,3,5-trichloromethylbenzene, and 1,3,5-trifluoromethylbenzene.

[0031] The second aspect of the present invention provides a quinoline acyl chloride represented by formula III and a 2-substituted acetyl chloride represented by formula IV prepared by the above method.

[0032] The third aspect of the present invention provides a method for preparing a quinoline carboxylic acid herbicide, which hydrolyzes the quinoline acyl chloride represented by formula III prepared by the above method, or the quinoline acyl chloride represented by formula III above in a solvent to obtain the quinoline carboxylic acid herbicide represented by formula V. The reaction equation is:

[0033]

[0034] Preferably, the temperature of the hydrolysis reaction is 0-100 °C, and the reaction time is 1-10 h.

[0035] Preferably, the temperature of the hydrolysis reaction is 0-30 °C, and the reaction time is 2-3 h.

[0036] Preferably, the solvent is water or an alkyl acid.

[0037] Preferably, the alkyl acid is at least one of acetic acid, n-propionic acid, isopropyl acid, n-butyric acid, tert-butyric acid, valeric acid, caproic acid, enanthic acid, and octanoic acid.

[0038] The beneficial effects of the present invention are as follows:

[0039] (1) The present invention provides a green process route for co-producing quinoline acyl chloride and 2-substituted acetyl chloride using trichloromethylquinoline and 2-substituted acetic acid. This process method can obtain the above two compounds at one time without separately acyl chlorination. The reaction steps are few, the reaction time is short, the production efficiency is high, and a large amount of acylating reagents are avoided in the production process. There are no toxic and harmful by-products generated, reducing pollution, and having the advantages of industrial production.

[0040] (2) The present invention also provides a new method for preparing a quinoline carboxylic acid herbicide using quinoline acyl chloride. This method can obtain a quinoline carboxylic acid herbicide with a high yield only by hydrolyzing quinoline acyl chloride. The cost is low, the conditions are mild, it is easy to operate, and it is also very suitable for industrial production. Specific Embodiments

[0041] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate and explain the present invention and are not used to limit the present invention. Unless otherwise specified, the reagents involved in the embodiments of the present invention are all commercially available products and can be obtained through commercial channels; the various processes and methods not described in detail in the embodiments of the present invention are conventional methods well known in the art.

[0042] It should be noted that in the following embodiments, the trichloromethylquinoline shown in Formula I is represented by trichloromethylquinoline (I), and the 2-substituted acetyl chloride shown in Formula IV with the substituent combination No. 10 in Table 1 is represented by 2-substituted acetyl chloride (IV-10), and so on, to simplify the writing.

[0043] Example 1: Synthesis of Trichloromethylquinoline (I)

[0044] Add methylquinoline (VI) (21.2 g, 0.1 mol), azobisisobutyronitrile (0.16 g, 0.001 mol) and 20 mL of o-dichlorobenzene into a 250 mL reaction flask. After adding, start passing chlorine gas at 160 °C. After reacting for 4 h, take a sample for analysis. When the content of methylquinoline (VI) is confirmed to be below 0.4%, stop passing chlorine. Then, pass nitrogen gas into the reaction flask to blow out the unreacted chlorine gas and hydrogen chloride gas, and the tail gas is absorbed by sodium hydroxide solution. Concentrate the reaction solution for the next reaction.

[0045] Example 2: Synthesis of Trichloromethylquinoline (I)

[0046] Add methylquinoline (VI) (21.2 g, 0.1 mol), benzoyl peroxide (0.48 g, 0.002 mol) and 20 mL of chloroform into a 250 mL reaction flask. After adding, start passing chlorine gas at 100 °C. After reacting for 1 h, take a sample for analysis. When the content of methylquinoline (VI) is confirmed to be below 0.4%, stop passing chlorine. Then, pass nitrogen gas into the reaction flask to blow out the unreacted chlorine gas and hydrogen chloride gas, and the tail gas is absorbed by sodium hydroxide solution. Concentrate the reaction solution for the next reaction.

[0047] Example 3: Synthesis of Trichloromethylquinoline (I)

[0048] Add methylquinoline (VI) (21.2 g, 0.1 mol), potassium persulfate (0.14 g, 0.0005 mol) and 20 mL of 3,4,5-trichlorotrifluoromethylbenzene into a 250 mL reaction flask. After adding, start passing chlorine gas at 230 °C. After reacting for 10 h, take a sample for analysis. When the content of methylquinoline (VI) is confirmed to be below 0.4%, stop passing chlorine. Then, pass nitrogen gas into the reaction flask to blow out the unreacted chlorine gas and hydrogen chloride gas, and the tail gas is absorbed by sodium hydroxide solution. Concentrate the reaction solution for the next reaction.

[0049] Example 4: Synthesis of quinoline acyl chloride (III) and 2-substituted acetyl chloride (IV-10)

[0050] Add the reaction solution of Example 1 into a 250 mL reaction flask, dilute it with 20 mL of o-dichlorobenzene, then add 2-substituted acetic acid (II-10) (12.8 g, 0.1 mol) and FeCl3 (0.07 g, 0.0004 mol), stir and heat up to 140 °C for reaction for 2 h. Take a sample for analysis, confirm that the content of 2-substituted acetic acid (II-10) is below 0.4% and end the reaction. Distill off the solvent by rectification to separate the product, obtaining 24.2 g of quinoline acyl chloride (III) with a yield of 93.1%; obtaining 13.6 g of 2-substituted acetyl chloride (IV-10) with a yield of 92.5%.

[0051] Example 5: Synthesis of quinoline acyl chloride (III) and 2-substituted acetyl chloride (IV-10)

[0052] Add the reaction solution of Example 1 into a 250 mL reaction flask, dilute it with 20 mL of m-dichlorobenzene, then add 2-substituted acetic acid (II-10) (12.8 g, 0.1 mol) and AlCl3 (0.05 g, 0.0004 mol), stir and heat up to 140 °C for reaction for 2 h. Take a sample for analysis, confirm that the content of 2-substituted acetic acid (II-10) is below 0.4% and end the reaction. Distill off the solvent by rectification to separate the product, obtaining 22.1 g of quinoline acyl chloride (III) with a yield of 85.0%; obtaining 12.35 g of 2-substituted acetyl chloride (IV-10) with a yield of 84.0%.

[0053] Example 6: Synthesis of quinoline acyl chloride (III) and 2-substituted acetyl chloride (IV-10)

[0054] Add the reaction solution of Example 1 into a 250 mL reaction flask, dilute it with 20 mL of dichloromethane, then add 2-substituted acetic acid (II-10) (12.8 g, 0.1 mol) and trifluoroacetic acid (1.14 g, 0.01 mol), stir and heat up to 50 °C for reaction for 1 h. Take a sample for analysis, confirm that the content of 2-substituted acetic acid (II-10) is below 0.4% and end the reaction. Distill off the solvent by rectification to separate the product, obtaining 21.5 g of quinoline acyl chloride (III) with a yield of 82.3%; obtaining 11.3 g of 2-substituted acetyl chloride (IV-10) with a yield of 76.9%.

[0055] Example 7: Synthesis of quinoline acyl chloride (III) and 2-substituted acetyl chloride (IV-10)

[0056] Add the reaction solution of Example 1 to a 250 mL reaction flask, dilute it with 20 mL of dimethylformamide (DMF), then add 2-substituted acetic acid (II-10) (12.8 g, 0.1 mol) and 80% aqueous HNO3 solution (0.5 mL, 0.01 mol), stir and heat up to 200 °C for reaction for 6 h. Take a sample for analysis, confirm that the content of 2-substituted acetic acid (II-10) is below 0.4% and end the reaction. Distill off the solvent by rectification to separate the product, obtain 20.6 g of quinoline acyl chloride (III) with a yield of 79.2%; obtain 11.9 g of 2-substituted acetyl chloride (IV-10) with a yield of 80.1%.

[0057] Example 8: Synthesis of quinoline acyl chloride (III) and 2-substituted acetyl chloride (IV-10)

[0058] Add the reaction solution of Example 1 to a 250 mL reaction flask, dilute it with 20 mL of tetrahydrofuran (THF), then add 2-substituted acetic acid (II-10) (12.8 g, 0.1 mol) and 0.5 g of zeolite, stir and heat up to 140 °C for reaction for 6 h. Take a sample for analysis, confirm that the content of 2-substituted acetic acid (II-10) is below 0.4% and end the reaction. Distill off the solvent by rectification to separate the product, obtain 23.2 g of quinoline acyl chloride (III) with a yield of 89.2%; obtain 13.2 g of 2-substituted acetyl chloride (IV-10) with a yield of 89.7%.

[0059] Example 9: Synthesis of quinoline acyl chloride (III) and 2-substituted acetyl chloride (IV-6)

[0060] Add the reaction solution of Example 1 to a 250 mL reaction flask, dilute it with 20 mL of o-dichlorobenzene, then add 2-substituted acetic acid (II-6) (9.6 g, 0.1 mol) and FeCl3 (0.07 g, 0.0004 mol), stir and heat up to 140 °C for reaction for 2 h. Take a sample for analysis, confirm that the content of 2-substituted acetic acid (II-6) is below 0.4% and end the reaction. Distill off the solvent by rectification to separate the product, obtain 18.6 g of quinoline acyl chloride (III) with a yield of 71.5%; obtain 7.9 g of 2-substituted acetyl chloride (IV-6) with a yield of 69.4%.

[0061] Example 10: Synthesis of quinoline acyl chloride (III) and 2-substituted acetyl chloride (IV-57)

[0062] Add the reaction solution of Example 1 into a 250 mL reaction flask, dilute it with 20 mL of o-dichlorobenzene, then add 2-substituted acetic acid (II-57) (15.0 g, 0.1 mol) and FeCl3 (0.07 g, 0.0004 mol), stir and heat up to 140 °C for reaction for 2 h. Take a sample for analysis, confirm that the content of 2-substituted acetic acid (II-57) is below 0.4% and end the reaction. Distill off the solvent by rectification to separate the product, obtaining 18.9 g of quinoline acyl chloride (III) with a yield of 72.7%; obtaining 13.1 g of 2-substituted acetyl chloride (IV-57) with a yield of 78.2%.

[0063] Example 11: Synthesis of quinoline acyl chloride (III) and 2-substituted acetyl chloride (IV-113)

[0064] Add the reaction solution of Example 1 into a 250 mL reaction flask, dilute it with 20 mL of o-dichlorobenzene, then add 2-substituted acetic acid (II-113) (21.2 g, 0.1 mol) and FeCl3 (0.07 g, 0.0004 mol), stir and heat up to 140 °C for reaction for 2 h. Take a sample for analysis, confirm that the content of 2-substituted acetic acid (II-113) is below 0.4% and end the reaction. Distill off the solvent by rectification to separate the product, obtaining 23.5 g of quinoline acyl chloride (III) with a yield of 90.4%; obtaining 21.3 g of 2-substituted acetyl chloride (IV-113) with a yield of 92.5%.

[0065] Example 12: Synthesis of quinoline carboxylic acid herbicide (V)

[0066] Add quinoline acyl chloride (III) (12.8 g, 0.1 mol) into a 250 mL reaction flask, cool it in an ice-water bath, add 50 mL of water at this temperature, then stir and react at 25 °C for 3 h. Filter and wash with ethanol, and dry to obtain 24.0 g of the product with a yield of 99.2%.

[0067] Example 13: Synthesis of quinoline carboxylic acid herbicide (V)

[0068] Add quinoline acyl chloride (III) (12.8 g, 0.1 mol) into a 250 mL reaction flask, cool it in an ice-water bath, add 50 mL of water at this temperature, then stir and react at 16 °C for 6 h. Filter and wash with ethanol, and dry to obtain 23.8 g of the product with a yield of 98.3%.

[0069] Example 14: Synthesis of quinoline carboxylic acid herbicide (V)

[0070] Add quinoline acyl chloride (III) (12.8 g, 0.1 mol) into a 250 mL reaction flask, cool it in an ice-water bath, add 50 mL of water at this temperature, then stir and react at 50 °C for 10 h. Filter and wash with ethanol, and dry to obtain 23.9 g of the product with a yield of 98.7%.

[0071] Example 15: Synthesis of Quinoline Carboxylic Acid Herbicides (V)

[0072] Add quinoline acyl chloride (III) (12.8 g, 0.1 mol) into a 250 mL reaction flask, cool it in an ice-water bath, add 50 mL of acetic acid at this temperature, then stir and react at 5 °C for 1 h. After filtration, wash with ethanol and dry to obtain 24.0 g of the product, with a yield of 99.4%.

Claims

1. A method for co-producing quinolinecarbonyl chloride and 2-substituted acetyl chloride from trichloromethylquinoline and 2-substituted acetic acid, characterized in that, The method uses the quinoline with trichloromethyl group shown in Formula I and 2-substituted acetic acid shown in Formula II as raw materials, reacts in a solvent under the action of a catalyst, and then obtains the quinoline acyl chloride shown in Formula III and 2-substituted acetyl chloride shown in Formula IV through rectification. The reaction equation is as follows: Wherein, R 1 , R 2 , R 3 are independently selected from any one of H, halogen, C1-C6 alkyl, substituted or unsubstituted phenyl, nitro, hydroxyl, and cyano.

2. The method according to claim 1, wherein The said R 1 , R 2 , R 3 is selected from any one of the substituent combinations shown in Table 1. Table 1 3. The method according to claim 1, characterized in that, In the said reaction, the molar ratio of the quinoline with trichloromethyl group shown in Formula I to the catalyst is 10 - 1000:1; the reaction temperature is 50 - 200 °C, and the reaction time is 1 - 6 h.

4. The method according to claim 3, wherein The molar ratio of the quinoline with trichloromethyl group shown in Formula I to the catalyst is 100 - 500:1; the reaction temperature is 100 - 160 °C, and the reaction time is 2 - 3 h.

5. The method according to claim 1, characterized in that, The said catalyst is selected from one or more of Lewis acids, inorganic acids, organic acids, acidic ionic liquids, molecular sieves, and zeolites.

6. The method according to claim 1, wherein The said solvent is selected from one or more of dichloromethane, dichloroethane, hexane, pentane, ethanol, methanol, isopropanol, n-butanol, tert-butanol, pentanol, dimethyl sulfoxide, dimethylformamide, tetrahydrofuran, diethylene glycol dimethyl ether, o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, chlorobenzene, chloroform, carbon tetrachloride, 4-chlorobenzotrifluoride, 3,4,5-trichlorobenzotrifluoride, 1,3,5-trichloromethylbenzene, 1,3,5-trifluoromethylbenzene, toluene, and benzene.

7. The method according to claim 1, characterized in that, The quinoline with trichloromethyl group shown in Formula I is prepared by the side-chain chlorination reaction of methylquinoline shown in Formula VI and an initiator in a solvent. The reaction equation is as follows:

8. The method according to claim 7, characterized in that, In the said side-chain chlorination reaction, the molar ratio of methylquinoline shown in Formula VI to the initiator is 50 - 200:1; the reaction temperature is 100 - 230 °C, and the reaction time is 1 - 10 h.

9. The method according to claim 8, wherein The molar ratio of methylquinoline shown in Formula VI to the initiator is 80 - 120:1; the reaction temperature is 150 - 180 °C, and the reaction time is 2 - 6 h.

10. The method according to claim 7, wherein The said initiator is selected from one or more of azo initiators, peroxide initiators, and persulfate initiators.

11. The method according to claim 7, characterized in that, The said solvent is selected from one or more of o-dichlorobenzene, m-dichlorobenzene, p-dichlorobenzene, chlorobenzene, chloroform, carbon tetrachloride, 4-chlorobenzotrifluoride, 3,4,5-trichlorobenzotrifluoride, 1,3,5-trichloromethylbenzene, and 1,3,5-trifluoromethylbenzene.

12. The quinoline acyl chloride shown in Formula III and 2-substituted acetyl chloride shown in Formula IV prepared by the method according to any one of claims 1 - 11.

13. A preparation method of a quinoline carboxylic acid herbicide, characterized in that, The quinoline acyl chloride shown in Formula III prepared by the method according to any one of claims 1 - 11, or the quinoline acyl chloride shown in Formula III according to claim 12 is subjected to a hydrolysis reaction in a solvent to obtain the quinoline carboxylic acid herbicide shown in Formula V. The reaction equation is as follows:

14. The preparation method according to claim 13, characterized in that, The temperature of the said hydrolysis reaction is 0 - 100 °C, and the reaction time is 1 - 10 h.

15. The preparation method according to claim 14, characterized in that, The temperature of the said hydrolysis reaction is 0 - 30 °C, and the reaction time is 2 - 3 h.

16. The preparation method according to claim 13, characterized in that, The said solvent is water or an alkyl acid.

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