CN114181141A - Preparation method of boscalid crystal form I - Google Patents
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- CN114181141A CN114181141A CN202111495730.XA CN202111495730A CN114181141A CN 114181141 A CN114181141 A CN 114181141A CN 202111495730 A CN202111495730 A CN 202111495730A CN 114181141 A CN114181141 A CN 114181141A
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D213/00—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members
- C07D213/02—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members
- C07D213/04—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom
- C07D213/60—Heterocyclic compounds containing six-membered rings, not condensed with other rings, with one nitrogen atom as the only ring hetero atom and three or more double bonds between ring members or between ring members and non-ring members having three double bonds between ring members or between ring members and non-ring members having no bond between the ring nitrogen atom and a non-ring member or having only hydrogen or carbon atoms directly attached to the ring nitrogen atom with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D213/78—Carbon atoms having three bonds to hetero atoms, with at the most one bond to halogen, e.g. ester or nitrile radicals
- C07D213/81—Amides; Imides
- C07D213/82—Amides; Imides in position 3
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
- C07B2200/00—Indexing scheme relating to specific properties of organic compounds
- C07B2200/13—Crystalline forms, e.g. polymorphs
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Abstract
The invention relates to a preparation method of boscalid crystal form I, which comprises the steps of dissolving anhydrous boscalid in a water-insoluble organic solvent to obtain a solution, adding the solution into hot water for flash evaporation of the solvent to obtain a wet boscalid crystal form I product suspended in the water, cooling, filtering and drying to obtain the boscalid crystal form I product. The preparation method of the boscalid crystal form I realizes the stable preparation of the boscalid crystal form I, has low transformation difficulty and is easy to realize industrial production; the obtained boscalid crystal form I has stable quality and little solvent residue.
Description
Technical Field
The invention belongs to the technical field of pesticide production, and particularly relates to a preparation method of boscalid crystal form I.
Background
The boscalid is used as a carboxamide bactericide, has extremely excellent control effect on diseases such as black spot, powdery mildew, gray mold and the like, has special effect on gray mold of various crops such as red cotton, grapes, strawberries, melons and the like, and has the excellent characteristics of high diffusion speed, obvious curative effect, quick absorption, safety to the crops, long lasting period, low environmental pollution, rain wash resistance and the like.
In the preparation process of the boscalid raw pesticide, different crystal forms can be obtained by different crystallization technologies, and the application range of the boscalid raw pesticide in the field of preparation is different. There are three types of boscalid crystal forms reported at present, namely a crystal form II, a crystal form I and a monohydrate crystal form.
Chinese patent CN100494179C discloses a new crystal form of dehydrated boscalid, namely a boscalid crystal form II, a preparation method thereof and application in the field of preparation.
Chinese patent CN 1275943C discloses crystalline hydrates of nicotinanilide and benzanilide, comprising boscalid monohydrate, which are prepared by dissolving the crystalline hydrates of nicotinanilide and benzanilide in a water-soluble organic solvent and precipitating the hydrate of i by adding water.
Domestic literature reports on preparation of the boscalid crystal form I are few, and the boscalid crystal form I mainly comes from the problems that the preparation difficulty is high, the process is unstable and the crystal form is influenced. Therefore, the development of the boscalid original drug crystal form I has positive significance for the development of the bactericide industry in China.
Patent CN109071445A discloses a preparation method of a polymorphic form I of boscalid anhydride, which specifically comprises the following steps: dissolving polymorph form ii of boscalid anhydrate in a first solvent to give a solution, combining the resulting solution with water (in a slow manner), separating the solid from the solvent mixture, and drying the solid to obtain polymorph form I of boscalid anhydrate. In the patent, a solution containing boscalid is dropped into hot water, and the boscalid is forced out of the solvent by using water and then crystallized under the condition that the solvent and the water exist, so that the crystallization method has the following problems: (1) the crystallized out is likely to be hydrate; (2) the crystallized crystal form 1 is mixed in water and a solvent, and the existence of the solvent causes the equilibrium of dissolution and precipitation of the crystallized crystal form 1 solid in the solvent, so that the crystallized crystal form 1 is still dissolved and crystallized after a long time, and the stability of a wet crystal form is influenced; (3) in the drying process, a constant amount of solvent is remained in the wet crystal form 1, so that the process of dissolving the crystal form 1 in the solvent for recrystallization exists, namely, the possibility of crystal form transformation again is high in the drying process, and the crystal form is unstable.
Disclosure of Invention
The invention aims to provide a preparation method of a boscalid crystal form I, which realizes the stable preparation of the boscalid crystal form I, has low transformation difficulty and is easy to realize industrial production; the obtained boscalid crystal form I has stable quality and little solvent residue.
The technical scheme adopted by the invention for solving the problems is as follows: dissolving anhydrous boscalid in a water-insoluble organic solvent to obtain a solution, adding the solution into hot water for flash evaporation of the solvent to obtain a wet boscalid crystal form I product suspended in the water, and cooling, filtering and drying to obtain the boscalid crystal form I product.
The method comprises the following steps of adding a solution into hot water, wherein in the process of adding the solution into the hot water for flashing a solvent, feeding and flashing are synchronously carried out, namely, the process of flashing the solvent is completed in the feeding process, the feeding is finished, the flashing is finished, at the moment, the boscalid is completely precipitated, and only a trace amount of solvent is remained in the water and is wrapped in crystals of a boscalid crystal form 1.
Preferably, the preparation method of the boscalid crystal form I is characterized by comprising the following steps: the method comprises the following steps:
(1) adding dehydrated boscalid into a water-insoluble organic solvent at the temperature of 0-140 ℃ to dissolve to obtain a solution, wherein the mass ratio of the anhydrous boscalid to the water-insoluble organic solvent is 2: 1-1: 20;
(2) heating water to 40-100 ℃ and maintaining the temperature of a hot water system, wherein the mass ratio of the anhydrous boscalid to the hot water in the step (1) is 1: 1-100: 1;
(3) continuously adding the solution obtained in the step (1) into the step (2), controlling the feeding speed to keep the temperature of a hot water system at 40-100 ℃, taking out the water-insoluble organic solvent by hot water in the process, and separating out a boscalid crystal form I from a water system to obtain a boscalid crystal form I wet product suspended in water;
(4) and (4) cooling, filtering and drying the wet boscalid crystal form I product obtained in the step (3) to obtain a boscalid crystal form I product.
Preferably, the water-insoluble organic solvent is an alkane, an aromatic hydrocarbon, a halogenated hydrocarbon or a water-insoluble ether.
Preferably, the water-insoluble organic solvent is dichloromethane, 1, 2-dichloroethane, chlorobenzene, toluene, cyclohexane or methyl tert-butyl ether.
More preferably, the dissolving temperature of the anhydrous boscalid in the step (1) is 30-130 ℃.
More preferably, the mass ratio of the anhydrous boscalid to the water-insoluble organic solvent in the step (1) is 3: 1-1: 10.
More preferably, the hot water system temperature is 50-100 ℃.
More preferably, the drying conditions in step (4) are: the temperature is 40-140 ℃, and the pressure is-0.1-0 MPa.
The feeding speed depends on the heat load for heating hot water, the feeding speed can be faster when the heat load is larger, the feeding speed is in direct proportion to the heat load, the feeding speed is controlled to maintain the temperature of a hot water system within the range of 40-100 ℃, and the solvent dropped into the hot water system can be instantly evaporated in a short time.
Compared with the prior art, the invention has the advantages that:
(1) according to the preparation method of the boscalid crystal form I, anhydrous boscalid is dissolved in a water-insoluble organic solvent, the solvent is added into hot water for flash evaporation to obtain the boscalid crystal form I, the water-insoluble organic solvent is selected, the boscalid hydrate is not formed in the crystallization process, the water-insoluble organic solvent can be subjected to azeotropic distillation with water, the azeotropic distillation point is below the boiling point of water, and the water-insoluble organic solvent can be subjected to flash evaporation in the hot water.
(2) The method adopts a hot water system flash evaporation solvent crystallization method to prepare the boscalid crystal form I, the solution containing boscalid is dripped into hot water, the solvent is immediately vaporized, the product is separated out in the water, and the condition that the water contains a large amount of solvent (namely the water always has no solvent or the residual amount of the solvent is little) is avoided; in addition, the boscalid is insoluble in water and free of solvent at the flash evaporation temperature, so that the boscalid can not be dissolved or melted any more, the solvent in a wet product of the crystal form 1 is very little in the drying process, and the defect that the formed crystal form 1 is transformed is avoided.
(3) The invention provides a preparation method of a boscalid crystal form I, which realizes the stable preparation of the boscalid crystal form I, has low transformation difficulty and is easy to realize industrial production; the obtained boscalid crystal form I has stable quality and little solvent residue.
Drawings
FIG. 1 is a DSC melting point spectrum of boscalid form I of example 1 of the present invention.
FIG. 2 is an X-ray powder diffraction pattern of boscalid form I of example 1 of the present invention.
Detailed Description
The invention is described in further detail below with reference to the accompanying examples.
Example 1: preparation of boscalid crystal form I by hot water system flash evaporation of dichloromethane
Dissolving anhydrous boscalid solid in dichloromethane serving as a solvent to obtain a dichloromethane solution of boscalid, wherein the mass ratio of dehydrated boscalid to dichloromethane is 1:3, and the dissolving temperature is 35 ℃; preheating a hot water system to 55-60 ℃ and maintaining the water temperature, wherein the mass ratio of the dehydrated boscalid to the hot water is 1: 15; continuously dropwise adding a dichloromethane solution of boscalid into hot water, ensuring the feeding speed to keep the temperature of a hot water system at 55-60 ℃, realizing that dichloromethane is brought out by flash evaporation in the feeding process, and simultaneously separating out a boscalid crystal form I solid in the hot water system; and after the feeding is finished, cooling, filtering and collecting wet boscalid crystal form I materials, and drying at the temperature of 80 ℃ and under the pressure of-0.03 MPa to obtain an amide crystal form I product.
The measured solvent residue in the boscalid crystal form I wet material is 800ppm, and the solvent residue in the acylamide crystal form I product is 100 ppm.
As shown in fig. 1 and fig. 2, a DSC melting point spectrum of boscalid crystal form i of example 1 of the present invention and an X-ray powder diffraction spectrum of boscalid crystal form i of example 1 of the present invention are shown, respectively.
As can be seen from figure 1, the melting range of the boscalid crystal form I is 144.13-145.36 ℃, the heat of fusion is 85.8J/g, and the boscalid crystal form I is matched with that described in patent CN100494179C boscalid crystal form I.
As can be seen from figure 2, the boscalid crystal form I has characteristic diffraction angles 2 theta of 6, 9.5, 18 and 22.5.
Example 2
Dissolving anhydrous boscalid solid in a solvent 1, 2-dichloroethane to obtain a 1, 2-dichloroethane solution of boscalid, wherein the mass ratio of the dehydrated boscalid to the 1, 2-dichloroethane is 1:2, and the dissolving temperature is 80 ℃; preheating a hot water system to 90-95 ℃ and maintaining the water temperature, wherein the mass ratio of the dehydrated boscalid to the hot water is 1: 10; continuously dropwise adding a 1, 2-dichloroethane solution of boscalid into hot water, ensuring the feeding speed to keep the temperature of a hot water system at 90-95 ℃, realizing that the 1, 2-dichloroethane is brought out by flash evaporation in the feeding process, and simultaneously separating out a boscalid crystal form I solid in the hot water system; and after the feeding is finished, cooling, filtering and collecting wet boscalid crystal form I materials, and drying at the temperature of 90 ℃ and under the pressure of-0.06 MPa to obtain an amide crystal form I product.
The measured solvent residue in the boscalid crystal form I wet material is 1200ppm, and the solvent residue in the acylamide crystal form I product is 150 ppm.
Example 3: method for preparing boscalid crystal form I by using hot water system to flash-evaporate chlorobenzene
Dissolving anhydrous boscalid solid in solvent chlorobenzene to obtain a chlorobenzene solution of boscalid, wherein the mass ratio of dehydrated boscalid to chlorobenzene is 1:1.5, and the dissolving temperature is 130 ℃; preheating a hot water system to 95-98 ℃ and maintaining the water temperature, wherein the mass ratio of the dehydrated boscalid to the hot water is 1: 20; continuously dropwise adding a chlorobenzene solution of boscalid into hot water, ensuring the feeding speed to keep the temperature of a hot water system at 95-98 ℃, realizing that chlorobenzene is brought out by flash evaporation in the feeding process, and simultaneously separating out a boscalid crystal form I solid in the hot water system; and after the feeding is finished, cooling, filtering and collecting wet boscalid crystal form I materials, and drying at the temperature of 120 ℃ and under the pressure of-0.08 MPa to obtain the amide crystal form I product.
The measured solvent residue in the boscalid crystal form I wet material is 1500ppm, and the solvent residue in the acylamide crystal form I product is 200 ppm.
Example 4: boscalid crystal form I prepared by hot water system flash evaporation of toluene
Dissolving anhydrous boscalid solid in a solvent toluene to obtain a toluene solution of boscalid, wherein the mass ratio of dehydrated boscalid to toluene is 1:3, and the dissolving temperature is 95 ℃; preheating a hot water system to 93-98 ℃ and maintaining the water temperature, wherein the mass ratio of the dehydrated boscalid to the hot water is 1: 20; continuously dropwise adding a methylbenzene solution of boscalid into hot water, ensuring that the temperature of a hot water system is kept at 93-98 ℃ by controlling the feeding speed, realizing that methylbenzene is brought out by flash evaporation in the feeding process, and simultaneously separating out a boscalid crystal form I solid in the hot water system; and after the feeding is finished, cooling, filtering and collecting wet boscalid crystal form I materials, and drying at the temperature of 110 ℃ and under the pressure of-0.09 MPa to obtain the amide crystal form I product.
The measured solvent residue in the boscalid crystal form I wet material is 1000ppm, and the solvent residue in the acylamide crystal form I product is 150 ppm.
Example 5: boscalid crystal form I prepared by hot water system flash evaporation of cyclohexane
Dissolving anhydrous boscalid solid in solvent cyclohexane to obtain a cyclohexane solution of boscalid, and controlling the mass ratio of dehydrated boscalid to cyclohexane to be 1:6 and the dissolving temperature to be 75 ℃; preheating a hot water system to 85-90 ℃ and maintaining the water temperature, wherein the mass ratio of the dehydrated boscalid to the hot water is 1: 20; continuously dropwise adding a methylbenzene solution of boscalid into hot water, ensuring that the temperature of a hot water system is kept at 85-90 ℃ by controlling the feeding speed, realizing that cyclohexane is brought out by flash evaporation in the feeding process, and simultaneously separating out a boscalid crystal form I solid in the hot water system; and after the feeding is finished, cooling, filtering and collecting wet boscalid crystal form I materials, and drying at the temperature of 90 ℃ and under the pressure of-0.08 MPa to obtain the amide crystal form I product.
The measured solvent residue in the boscalid crystal form I wet material is 800ppm, and the solvent residue in the acylamide crystal form I product is 100 ppm.
Example 6: boscalid crystal form I prepared by flash evaporation of methyl tert-butyl ether in hot water system
Dissolving anhydrous boscalid solid in a solvent methyl tert-butyl ether to obtain a boscalid methyl tert-butyl ether solution, wherein the mass ratio of the dehydrated boscalid to the methyl tert-butyl ether is 1:5, and the dissolving temperature is 50 ℃; preheating a hot water system to 65-70 ℃, maintaining the water temperature, wherein the mass ratio of the dehydrated boscalid to the hot water of the hot water system is 1: 5; continuously dropwise adding the boscalid methyl tert-butyl ether solution into hot water, ensuring that the temperature of a hot water system is kept at 65-70 ℃ by controlling the feeding speed, realizing that the methyl tert-butyl ether is brought out by flash evaporation in the feeding process, and simultaneously separating out a boscalid crystal form I solid in the hot water system; and after the feeding is finished, cooling, filtering and collecting wet boscalid crystal form I materials, and drying at the temperature of 90 ℃ and under the pressure of-0.04 MPa to obtain an amide crystal form I product.
The measured solvent residue in the boscalid crystal form I wet material is 500ppm, and the solvent residue in the acylamide crystal form I product is 100 ppm.
In addition to the above embodiments, the present invention also includes other embodiments, and any technical solutions formed by equivalent transformation or equivalent replacement should fall within the scope of the claims of the present invention.
Claims (8)
1. A preparation method of boscalid crystal form I is characterized by comprising the following steps: dissolving anhydrous boscalid in a water-insoluble organic solvent to obtain a solution, adding the solution into hot water for flash evaporation of the solvent to obtain a wet boscalid crystal form I product suspended in the water, and cooling, filtering and drying to obtain a boscalid crystal form I product.
2. A method for preparing boscalid form i according to claim 1, characterized in that: the method comprises the following steps:
(1) adding dehydrated boscalid into a water-insoluble organic solvent at the temperature of 0-140 ℃ to dissolve to obtain a solution, wherein the mass ratio of the dehydrated boscalid to the water-insoluble organic solvent is 2: 1-1: 20;
(2) heating water to 40-100 ℃, and maintaining the temperature of a hot water system, wherein the mass ratio of the anhydrous boscalid to the hot water in the step (1) is 1: 1-100: 1;
(3) continuously adding the solution obtained in the step (1) into the step (2), controlling the feeding speed to maintain the temperature of a hot water system, taking out the water-insoluble organic solvent by hot water in the process, and separating out the boscalid crystal form I from a water system to obtain a boscalid crystal form I wet product suspended in water;
(4) and (4) cooling, filtering and drying the wet boscalid crystal form I product obtained in the step (3) to obtain a boscalid crystal form I product.
3. A method for preparing boscalid form i according to claim 1, characterized in that: the water-insoluble organic solvent is alkane, aromatic hydrocarbon, halogenated hydrocarbon or water-insoluble ether.
4. A method for preparing boscalid form i according to claim 3, characterized in that: the water-insoluble organic solvent is dichloromethane, 1, 2-dichloroethane, chlorobenzene, toluene, cyclohexane or methyl tert-butyl ether.
5. A method for preparing boscalid form i according to claim 2, characterized in that: the dissolving temperature of the dehydrated boscalid in the step (1) is 30-130 ℃.
6. A method for preparing boscalid form i according to claim 2, characterized in that: in the step (1), the mass ratio of the dehydrated boscalid to the water-insoluble organic solvent is 3: 1-1: 10.
7. A method for preparing boscalid form i according to claim 2, characterized in that: the temperature of the hot water system in the step (2) is the same as that of the hot water system in the step (3), and is 50-100 ℃.
8. A method for preparing boscalid form i according to claim 1, characterized in that: the drying conditions in the step (4) are as follows: the temperature is 40-140 ℃, and the pressure is-0.1-0 MPa.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115536581A (en) * | 2022-10-08 | 2022-12-30 | 河北兰升生物科技有限公司 | Preparation method of high-purity boscalid crystal form I |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040249164A1 (en) * | 2001-09-25 | 2004-12-09 | Matthias Bratz | Crystalline hydrates of nicotinic acid anilide and benzoyl anilide derivatives |
| CN109071445A (en) * | 2016-05-09 | 2018-12-21 | 江苏龙灯化学有限公司 | Method for preparing boscalid |
| CN109790124A (en) * | 2016-09-28 | 2019-05-21 | Upl 有限公司 | The method for being used to prepare the anhydrous Boscalid of form I and the anhydrous Boscalid of form II |
-
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040249164A1 (en) * | 2001-09-25 | 2004-12-09 | Matthias Bratz | Crystalline hydrates of nicotinic acid anilide and benzoyl anilide derivatives |
| CN109071445A (en) * | 2016-05-09 | 2018-12-21 | 江苏龙灯化学有限公司 | Method for preparing boscalid |
| CN109790124A (en) * | 2016-09-28 | 2019-05-21 | Upl 有限公司 | The method for being used to prepare the anhydrous Boscalid of form I and the anhydrous Boscalid of form II |
Non-Patent Citations (4)
| Title |
|---|
| 国家药典委员会组织编写: "《中华人民共和国药典 四部 2020年版》", vol. 1, 31 May 2020, 中国医药科技出版社, pages: 476 * |
| 夏征农主编: "《大辞海 化工轻工纺织卷》", vol. 1, 上海辞书出版社, pages: 12 * |
| 殷恭宽主编: "《物理化学》", vol. 1, 31 December 1993, 北京医科大学，中国协和医科大学联合出版社, pages: 79 - 80 * |
| 穆光照主编: "《实用溶剂手册》", vol. 1, 30 September 1990, 上海科学技术出版社, pages: 447 * |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115536581A (en) * | 2022-10-08 | 2022-12-30 | 河北兰升生物科技有限公司 | Preparation method of high-purity boscalid crystal form I |
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