Synthetic method of 2-methyl-4-chloropropionic acid-polyethylene glycol ester

Abstract

The invention provides a synthetic method of 2-methyl-4-chloropropionic acid-polyethylene glycol ester, and belongs to the technical field of preparation of 2-methyl-4-chloropropionic acid-polyethylene glycol ester. The method comprises the following steps: adding o-cresol, dichloroethane and a catalyst, and reacting sulfuryl chloride at the temperature of below 15 DEG C; performing separation to obtain p-chloro-o-cresol and 6-chloro-o-cresol; adding p-chloro-o-cresol, 2-chloropropionic acid and caustic soda liquid to synthesize 2-methyl-4-chloropropionic acid; 2-methyl-4-chloropropionic acid is acidized, cooled, crystallized and sliced, 2-methyl-4-chloropropionic acid, polyethylene glycol and a neutral catalyst are added for a reaction, and the di-2-(4-chloro-2-methyl-phenoxy) propionic acid-polyethylene glycol ester is synthesized. The method is simple in process, mild in reaction and high in yield. By means of the synthesis method, a qualified product with the p-chloro-o-cresol content larger than 99% can be produced, other phenol impurities are not contained, the synthesis quality of p-chloro-o-cresol is guaranteed, meanwhile, synthesis of 2-methyl-4-chloropropionic acid-polyethylene glycol ester is easier to control, the product quality can be greatly improved, and meanwhile the domestic blank is filled up.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of 2-methyl-4-chloropropionic acid-polyethylene glycol ester, in particular to a synthesis method of 2-methyl-4-chloropropionic acid-polyethylene glycol ester. Background Art

[0002] 2-Methyl-4-chloropropionic acid-polyethylene glycol ester is a commonly used chemical root inhibitor. During the production process of waterproof membrane, chemical root inhibitor [the main components are 2-Methyl-4-chloropropionic acid octyl ester and 2-Methyl-4-chloropropionic acid-polyethylene glycol ester] is added to prevent plant roots from approaching both sides (or one side) of the aluminum foil of the waterproof membrane, which can play a waterproof role and also has a certain effect of resisting plant root puncture.

[0003] Previously, some people tried to synthesize 2-methyl-4-chloropropionic acid by first synthesizing o-cresol and 2-chloropropionic acid, and then using the chlorination process production technology to produce 2-methyl-4-chloropropionic acid to synthesize 2-methyl-4-chloropropionic acid-polyethylene glycol ester, which had the following disadvantages:

[0004] It contains toxic and harmful substances such as phenol, which is harmful to the surrounding environment. The gas has a strong smell and is very harmful to plants. It is also a powder (explosion tests are required). Most importantly, it is not recognized by the market. Therefore, it has been impossible to synthesize qualified 2-Methyl-4-chloropropionic acid-polyethylene glycol ester products for a long time. Summary of the invention

[0005] In view of this, in order to solve the problem that qualified 2-methyl-4-chloropropionic acid-polyethylene glycol ester products cannot be synthesized in the prior art, the present invention provides a synthesis method of 2-methyl-4-chloropropionic acid-polyethylene glycol ester, which has a simple process, mild reaction and high yield. The synthesis method of the present invention can produce qualified products with a content of p-chloro-o-cresol greater than 99%, without other phenolic impurities, thereby ensuring the quality of the synthesis of p-chloro-o-cresol, and making the synthesis of 2-methyl-4-chloropropionic acid-polyethylene glycol ester easier to control and improving the product quality.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A method for synthesizing 2-methyl-4-chloropropionic acid-polyethylene glycol ester comprises the following steps:

[0008] Step (1), adding o-cresol, ethylene dichloride and a catalyst into a reaction kettle, and adding sulfuryl chloride dropwise for 10-12 hours while controlling the temperature below 15° C., and detecting the content of the crude product after the reaction, wherein the amount of sulfuryl chloride added dropwise is 103% of the theoretical amount;

[0009] Step (2), separating the reaction product of step (1) to obtain p-chloro-o-cresol and 6-chloro-o-cresol;

[0010] Step (3), adding the p-chloro-o-cresol separated in step (2) and 2-chloropropionic acid and liquid alkali into the synthesis reactor to synthesize 2-methyl-4-chloropropionic acid;

[0011] Step (4), removing impurities from the 2-methyl-4-chloropropionic acid synthesized in step (3), putting it into an acidification kettle for acidification, cooling and crystallizing to obtain 2-methyl-4-chloropropionic acid crystals, adding dichloroethane, stirring and dissolving, separating the acidified water and the organic layer, and treating the salt-containing wastewater to remove three wastes;

[0012] Step (5), adding the 2-methyl-4-chloropropionic acid crystals obtained in step (4), additional polyethylene glycol and an additional neutral catalyst into the synthetic polyester kettle to react and synthesize 2-methyl-4-chloropropionic acid-polyethylene glycol ester, and obtaining qualified 2-methyl-4-chloropropionic acid-polyethylene glycol ester after passing the inspection.

[0013] Preferably, in step (2), separation is performed by a rectification kettle, specifically:

[0014] After the synthesis in step (1) is completed, the mixture is transferred to a desolventizing kettle, where the temperature is increased to remove ethylene dichloride and nitrogen is used to purge the mixture to remove the residual hydrogen chloride and sulfur dioxide gases. After no liquid solvent is evaporated, the mixture is transferred to the distillation kettle for separation.

[0015] Preferably, in step (3), the concentration of liquid caustic soda is 32%.

[0016] Preferably, in step (3), the reaction temperature is controlled at 100-110° C., the p-chloro-o-cresol is controlled to be below 1%, and the conversion rate is above 98%.

[0017] Preferably, in step (4), the reaction mixture is acidified at 80° C. and the pH value is detected and maintained below 2. After reacting for 2 hours, the temperature is lowered to 30° C. to obtain 2-methyl-4-chloropropionic acid crystals.

[0018] Preferably, in step (5), the polyethylene glycol is PEG200 and / or PEG300.

[0019] Preferably, when PEG200 and PEG300 are added simultaneously, the mass ratio of the two is 25:9.

[0020] Preferably, the neutral catalyst in step (5) is butyl stannoic acid.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The synthesis method of 2-methyl-4-chloropropionic acid-polyethylene glycol ester provided by the present invention has simple process, mild reaction and high yield. The synthesis method of the present invention can produce qualified products with a content of p-chloro-o-cresol greater than 99% and free of other phenolic impurities, thereby ensuring the quality of the synthesis of p-chloro-o-cresol, and making the synthesis of 2-methyl-4-chloropropionic acid-polyethylene glycol ester easier to control and improving the product quality.

[0023] The invention is used to produce 2-methyl-4-chloropropionic acid from 4-chloro-ortho-cresol. The effective amount of the synthesized 2-methyl-4-chloropropionic acid-polyethylene glycol ester is as high as 87.5%, which is 18-20% higher than the existing technology (the effective content of the synthesized 2-methyl-4-chloropropionic acid in the existing technology is up to 68%), greatly reducing the cost (the existing price is 300,000 yuan / ton, and the current price of our company is 81,000 yuan / ton), and filling the blank of the technology.

[0024] The actual measured values ​​of 2-methyl-4-chloropropionic acid-polyethylene glycol ester synthesized by the synthesis method of the present invention are: MCPP acid content <1%, single-end-capped monomer <10-12%, double-end-capped dimer>86-89%, single-end-capped + double-end-capped content>98%, group standard>100%, which are much higher than the existing qualified detection standard: polymer root inhibitor, final control standard: detection MCPP acid content <1%, single-end-capped monomer <22%, double-end-capped dimer>68%, single-end-capped + double-end-capped content>90%. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The synthetic flow chart of the present invention is shown in FIG. DETAILED DESCRIPTION

[0026] The key to improving the quality of 2-Methyl-4-chloropropionic acid-polyethylene glycol ester products is to increase the content of 4-chloro-o-cresol...

[0027] The prior art uses o-cresol to chlorinate first, and phenol is present in the chlorination process, the isomer content is high, and the polychlorination phenomenon cannot be solved, resulting in the inability to synthesize high-quality 2-methyl-4-chloropropionic acid-polyethylene glycol ester in the prior art.

[0028] In order to synthesize 2-methyl-4-chloropropionic acid-polyethylene glycol ester with good quality, the isomer content is well controlled to make the o-cresol as completely chlorinated as possible, and the most important thing is to avoid the phenomenon of polychlorination to ensure the quality of the o-chloro-o-cresol.

[0029] To this end, the present invention provides a method for synthesizing 2-methyl-4-chloropropionic acid-polyethylene glycol ester, comprising the following steps:

[0030] Step (1), adding o-cresol, ethylene dichloride and a catalyst into a reaction kettle, and adding sulfuryl chloride dropwise for 10-12 hours while controlling the temperature below 15° C., and detecting the content of the crude product after the reaction, wherein the amount of sulfuryl chloride added dropwise is 103% of the theoretical amount;

[0031] Wherein, o-cresol and ethylene dichloride are preferably added in 20 parts and 20 parts by weight, respectively, and the amount of catalyst added is added according to actual production;

[0032] The dropping speed of sulfuryl chloride is preferably from fast to slow, and the dropping amount is preferably 25.75 parts by weight;

[0033] Step (2), separating the reaction product of step (1) to obtain p-chloro-o-cresol and 6-chloro-o-cresol;

[0034] The reaction product of step (1) is preferably separated by a distillation kettle to obtain p-chloro-o-cresol and 6-chloro-o-cresol, which can be specifically:

[0035] After the synthesis in step (1) is completed, the mixture is transferred to a desolventizing kettle, the temperature is increased to remove ethylene dichloride, and nitrogen is used to purge the mixture to remove the residual hydrogen chloride and sulfur dioxide gases. After no liquid solvent is evaporated, the mixture is transferred to the distillation kettle for separation;

[0036] Step (3), adding the p-chloro-o-cresol separated in step (2) and 2-chloropropionic acid and liquid alkali into the synthesis reactor to synthesize 2-methyl-4-chloropropionic acid;

[0037] Wherein, in step (3), the added 4-chloro-o-cresol, 2-chloropropionic acid and liquid alkali are preferably 15 parts, 7-8 parts and 16 parts by weight, respectively;

[0038] Wherein, the concentration of liquid alkali is preferably 32%; in step (3), the reaction temperature is preferably controlled at 100-110°C, the para-chloro-o-cresol is controlled to be below 1%, and the conversion rate is above 98%;

[0039] The synthesis amount of 2-methyl-4-chloropropionic acid is about 22.5 parts.

[0040] Step (4), after removing impurities from the 2-methyl-4-chloropropionic acid synthesized in step (3) (after treating the coating salt and the medium), the 2-methyl-4-chloropropionic acid is put into an acidification kettle for acidification, cooling and crystallizing to obtain 2-methyl-4-chloropropionic acid crystals, adding dichloroethane, stirring and dissolving, separating the acidified water and the organic layer, and treating the salt-containing wastewater to remove the three wastes;

[0041] Wherein, the added amount of ethylene dichloride is preferably 20-30 parts by weight.

[0042] Wherein, in step (4), it is preferred to acidify at 80°C while detecting and maintaining the pH value below 2. After reacting for 2 hours, the temperature is lowered to 30°C to obtain 2-methyl-4-chloropropionic acid crystals.

[0043] Step (5), adding the 2-methyl-4-chloropropionic acid crystals obtained in step (4), additional polyethylene glycol and an additional neutral catalyst into the synthetic polyester kettle for reaction to synthesize di-2-(4-chloro-2-methyl-phenoxy) propionic acid-polyethylene glycol ester, and obtaining qualified di-2-(4-chloro-2-methyl-phenoxy) propionic acid-polyethylene glycol ester after passing the inspection.

[0044] Wherein, in step (5), preferably the polyethylene glycol is PEG200 and / or PEG300.

[0045] When PEG200 and PEG300 were added simultaneously, the mass ratio of the two was 25:9.

[0046] The neutral catalyst is preferably butylstannoic acid.

[0047] In the synthesis method provided by the invention, o-cresol is first chlorinated, and the crude product content is: o-cresol <0.05%, isomer <5.75%, p-chloro-o-cresol>94%, and other impurities <0.2% in total.

[0048] In the prior art, the crude product produced by BASF contains: 5% isomers, 94.8% p-chloro-o-cresol, and 0.2% other impurities.

[0049] It can be seen that in the synthesis method of the present invention, the crude product content of o-cresol in the first chlorination is better than that of the crude product produced by BASF. The crude product synthesized by the present invention is refined to obtain 6-chloro-o-cresol (content 99.5%, isomers are sold), and the content of p-chloro-o-cresol is 99%-99.7% (more than 99% is a qualified product).

[0050] The technical solution of the present invention is clearly described in detail below in conjunction with specific embodiments.

[0051] Preparation Example

[0052] Preparation of 4-chloro-o-cresol and 2-methyl-4-chloropropionic acid

[0053] Step (1), add 2000 kg of o-cresol into a 5000 L reactor, add 2000 kg of ethylene dichloride and a catalyst, and add sulfuryl chloride dropwise at a temperature below 15° C., strictly control the speed and amount of addition (from fast to slow, the reaction time is about 11 hours, the amount of addition is 2575 kg, which is 103% of the theoretical amount). After the reaction, the crude product content is detected, and p-chloro-o-cresol accounts for 94-94.5%, and 6-o-cresol accounts for 5-5.5%.

[0054] Step (2), transfer to a desolventizing kettle, raise the temperature to remove dichloroethane, and simultaneously purge with nitrogen to drive out the residual hydrogen chloride and sulfur dioxide gas. After no liquid solvent is evaporated, transfer to a distillation kettle for separation to obtain 6-chloro-o-cresol with a content of 99.5% (packaged in 200KG plastic barrels for sale) and p-chloro-o-cresol with a main product content of 99% (packaged in 200KG galvanized barrels for sale). The self-use portion is measured and then injected into the next step of 2-methyl-4-chloropropionic acid production.

[0055] Step (3), add 1500KG of p-chloro-o-cresol (content is 99%) into a 5000L reactor, add 1600KG of 32% liquid caustic soda, heat to 110 degrees and reflux for 1 hour, then start dehydration (water volume is about 850KG) and end. Prepare to dropwise add 800KG of 2-chloropropionic acid. The reaction temperature is controlled at 100°C, the p-chloro-o-cresol is controlled to be below 1%, and the conversion rate is above 98%.

[0056] Step (4), after passing the test, transfer the material to the acidification kettle, add 500KG of water into the kettle to facilitate the transfer of the material, put 2000L of 30% hydrochloric acid into the 10000L acidification kettle, acidify at 80°C and detect the pH value while maintaining it at 2. After reacting for 2 hours, when the temperature drops to 30°C, 2-methyl-4-chloropropionic acid crystals appear, and the amount of the synthetic product is about 2250KG. Add 2500KG of ethylene dichloride, the temperature is 40°C, stir and dissolve to complete, static separation, acidification water and organic layer, saline waste water to remove three wastes (three-effect evaporation), the organic layer to the desolventizing kettle, slice after desolventizing, and can be packaged and sold. The 2-methyl-4-chloropropionic acid content is above 96%, and the self-use part is measured and injected into the synthetic polyester kettle.

[0057] The following examples all use the 2-methyl-4-chloropropionic acid prepared in the above preparation example.

[0058] Example 1

[0059] Add PEG20034ɡ, catalyst 3ɡ (sulfuric acid) and 2-methyl-4-chloropropionic acid 60.5ɡ into a 500ML glass kettle.

[0060] Under stirring, the temperature was raised to 120℃ and the vacuum pump was turned on. Water began to be released. When the temperature was raised to 180℃, almost no water was released. It was named Wangzhou PEG200. Under this condition, the temperature was maintained at 185℃ for 2-3 hours. The reaction results were as follows:

[0061] The residual MCPP is about 2.8%, the monomer is 25%, and the dimer is 72%; (basically in line with the previous quality standards, but contains acidic medium, is difficult to handle, has a low yield, and the effluent is about 5ɡ).

[0062] Example 2

[0063] Add PEG30034ɡ, catalyst 3ɡ (p-toluenesulfonic acid) and 60.5ɡ of 2-methyl-4-chloropropionic acid into a 500ML glass kettle.

[0064] Under stirring, the temperature was raised to 120℃, and the vacuum pump was turned on to start removing the generated water. When the temperature was raised to 180℃, almost no water was produced. In this case, the temperature was maintained at 185℃, and the reaction results were tested after 2-3 hours as follows:

[0065] The residual MCPP is about 2.9%, the monomer is 21% and the dimer is 76.1% (basically in line with the previous quality standards, but still contains acidic medium, is difficult to handle, has a low yield, and the effluent is about 5ɡ).

[0066] Example 3

[0067] Add PEG200 25ɡ, PEG300 9ɡ (total 34ɡ), neutral catalyst 3ɡ (butyl stannoic acid), and 2-methyl-4-chloropropionic acid 60.5ɡ into a 500ML glass kettle.

[0068] Heat to 120℃ under stirring, start vacuum pump, start to remove generated water, when temperature rises to 180℃, basically no water comes out. In this case, keep temperature at 185℃, wait for 2-3 hours, and the reaction results are as follows:

[0069] The residual MCPP is about 2.3%, the monomer is 14%, the dimer is 83.7%, (basically in line with the previous quality standards, but the residual propionic acid still exceeds the set value, it is recommended to use it after treatment with 2-methyl-4-chloropropionic acid, the effluent is about 5ɡ).

[0070] Example 4

[0071] Add PEG20025ɡ, PEG3009ɡ (total 34ɡ), neutral catalyst 3ɡ (butyl stannoic acid) and 2-methyl-4-chloropropionic acid 60.5ɡ (after treatment with encapsulating salt and medium) into a 500ML glass kettle.

[0072] The temperature was raised to 120°C under stirring, and the vacuum pump was turned on to start the removal of generated water. When the temperature was raised to 180°C, almost no water was produced, and it was named Wangzhou PEG225. In this case, the temperature was maintained at 185°C. After 2-3 hours, the reaction results were as follows:

[0073] The residual MCPP is about 0.6%, the monomer is 11.9%, the dimer is 87.5%, (fully meets and exceeds all current quality standards, the residual propionic acid meets the set value of ≤1%, it is recommended to use it after treatment with 2-methyl-4-chloropropionic acid, and the effluent is about 5ɡ).

[0074] The present invention provides technical support for the production of high-quality qualified 2-methyl-4-chloropropionic acid-polyethylene glycol ester through reasonable PEG preparation, application of neutral catalyst, and 2-methyl-4-chloropropionic acid treatment and cleaning. It fully meets all standard requirements of all production products, reduces the amount of root inhibitor added, has high quality and low price, saves a lot of costs, is currently in large-scale production, and has been applied and supported by Keshun Co., Ltd. for ordering, which provides a solid foundation for the comprehensive market.

[0075] 2-Methyl-4-chloropropionic acid-polyethylene glycol ester detection

[0076]

[0077]

[0078] Asphalt test

[0079]

Claims

1. A method for synthesizing 2-methyl-4-chloropropionic acid-polyethylene glycol ester, characterized in that: The steps include: Step (1), adding o-cresol, ethylene dichloride and a catalyst into a reaction kettle, and adding sulfuryl chloride dropwise for 10-12 hours while controlling the temperature below 15° C., and detecting the content of the crude product after the reaction, wherein the amount of sulfuryl chloride added dropwise is 103% of the theoretical amount; Step (2), separating the reaction product of step (1) to obtain p-chloro-o-cresol and 6-chloro-o-cresol; Step (3), adding the p-chloro-o-cresol separated in step (2) and 2-chloropropionic acid and liquid alkali into the synthesis reactor to synthesize 2-methyl-4-chloropropionic acid; Step (4), removing impurities from the 2-methyl-4-chloropropionic acid synthesized in step (3), putting it into an acidification kettle for acidification, cooling and crystallizing to obtain 2-methyl-4-chloropropionic acid crystals, adding dichloroethane, stirring and dissolving, separating the acidified water and the organic layer, and treating the salt-containing wastewater to remove three wastes; Step (5), adding the 2-methyl-4-chloropropionic acid crystal slices obtained in step (4), additional polyethylene glycol and an additional neutral catalyst into the synthetic polyester kettle to react and synthesize 2-methyl-4-chloropropionic acid-polyethylene glycol ester, and obtaining qualified 2-methyl-4-chloropropionic acid-polyethylene glycol ester after passing the inspection.

2. The method for synthesizing 2-methyl-4-chloropropionic acid-polyethylene glycol ester according to claim 1, characterized in that: In step (2), separation is carried out by a rectification kettle, specifically: After the synthesis in step (1) is completed, the mixture is transferred to a desolventizing kettle, where the temperature is increased to remove ethylene dichloride and nitrogen is used to purge the mixture to remove the residual hydrogen chloride and sulfur dioxide gases. After no liquid solvent is evaporated, the mixture is transferred to the distillation kettle for separation.

3. The method for synthesizing 2-methyl-4-chloropropionic acid-polyethylene glycol ester according to claim 1, characterized in that: In step (3), the concentration of liquid caustic soda is 32%.

4. The method for synthesizing 2-methyl-4-chloropropionic acid-polyethylene glycol ester according to claim 1, characterized in that: In step (3), the reaction temperature is controlled at 100-110° C., the p-chloro-o-cresol is controlled to be below 1%, and the conversion rate is above 98%.

5. The method for synthesizing 2-methyl-4-chloropropionic acid-polyethylene glycol ester according to claim 1, characterized in that: In step (4), the reaction mixture is acidified at 80° C. and the pH value is detected and maintained below 2. After reacting for 2 hours, the temperature is lowered to 30° C. to obtain 2-methyl-4-chloropropionic acid crystals.

6. The method for synthesizing 2-methyl-4-chloropropionic acid-polyethylene glycol ester according to claim 1, characterized in that: In step (5), the polyethylene glycol is selected from PEG200 and / or PEG300.

7. The method for synthesizing 2-methyl-4-chloropropionic acid-polyethylene glycol ester according to claim 6, characterized in that: When PEG200 and PEG300 were added simultaneously, the mass ratio of the two was 25:

9.

8. A method for synthesizing 2-methyl-4-chloropropionic acid-polyethylene glycol ester according to any one of claims 1 to 7, characterized in that: The neutral catalyst in step (5) is butyl stannoic acid.

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