CN114957122A - Preparation method of 10-methoxyiminostilbene - Google Patents
Preparation method of 10-methoxyiminostilbene Download PDFInfo
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- CN114957122A CN114957122A CN202210523718.3A CN202210523718A CN114957122A CN 114957122 A CN114957122 A CN 114957122A CN 202210523718 A CN202210523718 A CN 202210523718A CN 114957122 A CN114957122 A CN 114957122A
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- potassium bromide
- water
- methoxyiminostilbene
- mother liquor
- potassium
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D223/00—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom
- C07D223/14—Heterocyclic compounds containing seven-membered rings having one nitrogen atom as the only ring hetero atom condensed with carbocyclic rings or ring systems
- C07D223/18—Dibenzazepines; Hydrogenated dibenzazepines
- C07D223/22—Dibenz [b, f] azepines; Hydrogenated dibenz [b, f] azepines
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W10/00—Technologies for wastewater treatment
- Y02W10/30—Wastewater or sewage treatment systems using renewable energies
- Y02W10/37—Wastewater or sewage treatment systems using renewable energies using solar energy
Abstract
The application relates to the field of pharmaceutical intermediates, and particularly discloses a preparation method of 10-methoxyiminostilbene, which comprises a feeding step, a reaction step, a water washing step and a crystallization step, wherein the water washing step comprises adding water for layering, and layering and separating an organic layer and a water layer; also comprises a recycling step, wherein the recycling step comprises the following steps: recovering methanol, neutralizing, decoloring, distilling under reduced pressure, and purifying a potassium bromide crude product. By adding the recovery step, the methanol recovery solution, the first recovered water and the potassium bromide can be obtained, so that on one hand, the discharge amount of waste liquid is reduced, on the other hand, the obtained potassium bromide can be sold, and the production cost is saved; the purification step and the step of preparing the crude potassium bromide only have the vacuum drying step, and most of the used equipment is the same, so that the equipment types are less, the utilization efficiency of the equipment is improved, and the equipment cost is saved.
Description
Technical Field
The application relates to the technical field of preparation of oxcarbazepine drug intermediates, in particular to a preparation method of 10-methoxyiminostilbene.
Background
10-methoxy-5H-dibenzo [ b, f ]]Azepine, also known as 10-methoxyiminostilbene, known as 10-methoxy dibenz [ b, f [ ]]azepine of the formula C 15 H 13 NO, molecular weight 223.27, as a bright yellow crystalline powder in appearance, having the following structure:
an invention patent with application publication No. CN106467491A discloses a method for preparing 10-methoxy-5H-dibenzo [ b, f ] azepine, comprising a feeding step, a reaction step, a water washing step, and a crystallization step, wherein a reaction solvent is a mixed solvent of methanol and an aromatic solvent, and the method is characterized in that the temperature of the water washing step is 65-70 ℃, and an activated carbon treatment step is added in the water washing step; the crystallization step adopts an aromatic solvent, C1-C3 alcohol and water azeotropic method to remove the solvent.
The reaction formula for producing 10-methoxy-5H-dibenzo [ b, f ] azepine from 10, 11-dibromoiminodibenzyl is as follows:
during the reaction, a large amount of alkali metal hydroxide KOH is required to be added, then a large amount of water is added for layering, the water layer is removed, and the organic layer is added with activated carbon for decoloring, filtering and other subsequent processes to prepare the 10-methoxy iminostilbene.
Usually, the mass ratio of KOH to 10, 11-dibromo-imino-dibenzyl is 3:2 during feeding, so that a large amount of potassium ions are contained in the water layer waste liquid obtained after water is added for layering for the first time, on one hand, the waste liquid cannot be directly discharged, on the other hand, the waste liquid contains not only potassium ions but also other impurities, and the waste liquid is difficult to continue to use, so that waste is caused.
Disclosure of Invention
In order to solve the problem that waste liquid containing a large amount of potassium ions is difficult to be continuously utilized, the application provides a preparation method of 10-methoxyiminostilbene.
The preparation method of 10-methoxyiminostilbene adopts the following technical scheme:
a preparation method of 10-methoxyiminostilbene comprises a feeding step, a reaction step, a water washing step and a crystallization step, wherein materials in the feeding step comprise 10, 11-dibromoiminodibenzyl, potassium hydroxide, methanol and an aromatic solvent mixed solvent, and the water washing step comprises adding water for layering and separating an organic layer and a water layer; also comprises a recycling step, wherein the recycling step comprises the following steps:
and (3) recovery of methanol: distilling the water layer to obtain methanol recovery liquid and potassium ion mother liquor;
neutralizing: adding hydrobromic acid into the potassium ion mother liquor, and adjusting the pH value to 6-7;
and (3) decoloring: adding first active carbon after neutralization, heating for decolorization, and filtering to remove the first active carbon;
and (3) reduced pressure distillation: distilling the components to obtain distilled waste liquid, and distilling the distilled components to obtain first recovered water to obtain a potassium bromide solution;
and (3) crystallization: cooling and crystallizing the potassium bromide solution, and separating to obtain a potassium bromide crude product and a first potassium bromide mother solution;
and (5) purifying a potassium bromide crude product.
By adopting the technical scheme, the organic layer and the water layer are obtained after the water washing step, the solvent in the organic layer is mainly toluene, the solvent in the water layer is mainly water and methanol, the water layer contains a large amount of potassium ions, the methanol is distilled out through different boiling points to obtain the methanol recovery liquid, and the methanol recovery liquid can be used as a raw material in the feeding step, so that the methanol recovery liquid can be recycled, and the cost is saved. Potassium ion mother liquor passes through hydrobromic acid neutralization back, produces potassium bromide, through first active carbon adsorption impurity after, filters, and most water is got rid of through vacuum distillation to the liquid phase, and the water of distilling off is first recovered water, and first recovered water can be used for acting as the raw materials of washing step, cyclic utilization, using water wisely. The rest part is high-concentration potassium bromide solution, and the first potassium bromide mother solution and the potassium bromide crude product are obtained through cooling and crystallization. After the potassium bromide crude product is purified, the purity can reach more than 94wt%, and the potassium bromide is a raw material commonly used in chemical industry and can be sold;
in conclusion, after the water layer obtained in the water washing step is treated in the recovery step, the methanol recovery liquid, the first recovery water and the potassium bromide crude product can be recovered, wherein the methanol recovery liquid and the first recovery water can be recycled, and the potassium bromide crude product has higher purity after purification, can be sold, reduces the discharge of waste water, and saves the production cost.
In the step of recovering the methanol, normal pressure distillation and super-gravity bed dehydration are adopted to obtain a methanol recovery solution and a potassium ion mother solution.
By adopting the technical scheme, the hypergravity bed is a baffling type hypergravity revolving bed, is novel efficient rectification equipment and is a machine consisting of one or more rotors rotating at high speed. The device has the effects of good performance, high efficiency, low energy consumption, small volume, safety, reliability and low management cost, and ensures that the methanol recovery solution and the potassium ion mother solution are conveniently separated.
Optionally, after cooling and crystallizing the potassium bromide solution, a potassium bromide crude product and a first potassium bromide mother solution are obtained through centrifugal separation.
By adopting the technical scheme, the potassium bromide and the potassium bromide are separated in a centrifugal mode, the potassium bromide is precipitated at the bottom, the first potassium bromide mother liquor can be removed in a pouring or sucking mode, and the separation speed is high; if adopt traditional filterable separation mode, have more result on the filter easily, make the later stage result shift inconvenient, and the filter screen blocks up easily, and the clearance or change filter screen all influence efficiency easily.
Through adopting above-mentioned technical scheme, have high concentration potassium bromide in the first potassium bromide mother liquor, can lead to first active carbon and add to the system together in, can carry out the secondary and precipitate, can not cause the waste.
Optionally, the purification step of the potassium bromide crude product comprises adding a second activated carbon and water into the potassium bromide crude product, heating, filtering to remove the second activated carbon, distilling under reduced pressure to remove water to obtain a second recovered water, cooling and crystallizing the rest, centrifuging to separate solid and liquid, and drying the solid in vacuum to obtain potassium bromide, wherein the liquid is a second potassium bromide mother solution.
By adopting the technical scheme, after the crude potassium bromide product is purified by the steps, the purity of the obtained potassium bromide is more than 94wt%, and the potassium bromide product has higher purity and is convenient for subsequent sale. And the purification step is only added with the step of vacuum drying with the step of preparing the crude potassium bromide, most of the used equipment is the same, and the preparation of the crude potassium bromide and the purification of the crude potassium bromide can be completed by less kinds of equipment, so that the utilization efficiency of the equipment is improved, and the equipment cost is saved. The second recovered water can be used for purifying the crude potassium bromide, and the second recovered water and the second active carbon can be added into the crude potassium bromide together for use, so that the water is recycled, and the water is saved.
Optionally, the second potassium bromide mother liquor is added together with the second activated carbon instead of water.
Through adopting above-mentioned technical scheme, contain the potassium bromide of high concentration in the second potassium bromide mother liquor, through adding it into the system with its substitute water and second active carbon together, make the difficult waste of potassium bromide in the second potassium bromide mother liquor, and reduce sewage discharge.
Optionally, 8-12 batches of the first potassium bromide mother liquor are mechanically used to form waste liquor, and the waste liquor is discharged.
By adopting the technical scheme, the impurity content of the first potassium bromide mother liquor is too high after the first potassium bromide mother liquor is mechanically used for 8-12 batches, and the purity of potassium bromide is easily influenced.
Optionally, 18-22 batches of the second potassium bromide mother liquor are mechanically applied to form waste liquor, and the waste liquor is discharged.
By adopting the technical scheme, after 18-22 batches of second potassium bromide mother liquor are mechanically used, the impurity content in the second potassium bromide mother liquor is too high, the purity of potassium bromide is easily influenced, and the second potassium bromide mother liquor needs to be discharged as waste liquor.
In summary, the present application has the following beneficial effects:
1. by adding the recovery step, the methanol recovery solution, the first recovered water and the potassium bromide can be obtained, so that on one hand, the discharge amount of waste liquid is reduced, on the other hand, the obtained potassium bromide with higher purity can be sold, and the production cost is saved;
2. the purification step and the step of preparing the crude potassium bromide only have the step of vacuum drying, and most of the used equipment is the same, so that the equipment types are less, the utilization efficiency of the equipment is improved, and the equipment cost is saved;
3. first potassium bromide mother liquor and first active carbon are added together, and second potassium bromide mother liquor and second active carbon are added together for potassium bromide is difficult extravagant in first potassium bromide mother liquor and the second potassium bromide mother liquor, reduces the sewage discharge simultaneously.
Drawings
FIG. 1 is a flow diagram of a process for the preparation of 10-methoxyiminostilbene provided herein.
Detailed Description
The present application is described in further detail below with reference to examples and fig. 1.
Examples
Referring to fig. 1, a method for preparing 10-methoxyiminostilbene comprises the following steps:
a material feeding step: adding 900kg of methanol into a reaction kettle, keeping the temperature of the methanol at 10 ℃, adding 1200kg of potassium hydroxide in batches, slowly adding 1200kg of toluene after the potassium hydroxide is completely dissolved, heating to 35-40 ℃, and slowly adding 600kg of 10, 11-dibromo-imino-dibenzyl.
The reaction steps are as follows: after the feeding is finished, the temperature is raised to 80-90 ℃, and the stirring reaction is carried out for 9 hours.
And (3) water washing: after the reaction is finished, cooling to 70 ℃, adding 1200kg of hot water at 70 ℃, stirring, standing and layering to form an organic layer and a water layer, and discharging 3360kg of the water layer; controlling the temperature of the organic layer to be 65-70 ℃, adding 10kg of active carbon, preserving the temperature, stirring for 0.5h, and filtering to remove the active carbon; adding 1200kg of hot water at 70 ℃, stirring, standing, layering, discharging 1210kg of secondary water layer, heating to 80 ℃, filtering while hot, distilling off 880kg of toluene by reduced pressure distillation (the vacuum degree is less than-0.08 MPa), and recycling the toluene.
A crystallization step: and cooling the residue after removing the toluene to 10 ℃ for crystallization, filtering, adding ethanol into a filter cake for washing for three times, adding water for washing for three times, filtering and drying by a three-in-one device to obtain yellow crystalline powder, wherein the powder is a finished product of 10-methoxyiminostilbene, the yield of the 10-methoxyiminostilbene obtained by calculation is 91.6%, and the toluene residue is measured to be 0.00wt 6%.
And (3) a recovery step:
s1, recovery of methanol: distilling 3360kg of water layer obtained in the water washing step through a supergravity bed at normal pressure, distilling to remove 795kg of methanol, and obtaining 2525kg of potassium ion mother liquor in the rest, wherein the methanol is recycled;
s2, neutralization: adding 2052kg of 48wt% hydrobromic acid into 2525kg of potassium ion mother liquor in batches under the condition of controlling the temperature to be 60 ℃, and measuring the pH to be 6.7;
s3, decoloring: after neutralization, adding 10kg of first active carbon and 60 ℃ of first potassium bromide mother liquor obtained in the cooling crystallization step, stirring for 0.5h, and filtering to remove the active carbon;
s4, reduced pressure distillation: distilling under reduced pressure (vacuum degree is less than or equal to-0.08 MP), and distilling for the first 0.5h to obtain distillate waste liquid (932 kg); the later distilled component is first recovered water, the first recovered water is 1250kg, and the remainder is a potassium bromide solution;
s5: and (3) crystallization: cooling the potassium bromide solution to 10 ℃ for crystallization, separating out white powder, namely potassium bromide, centrifuging and separating the powder from a liquid phase to obtain a crude potassium bromide product 2010kg and a first potassium bromide mother solution; the first potassium bromide and the first active carbon powder can be added into a decoloring link of a recovery step for recycling, and the first potassium bromide mother liquor is reused for 8-12 batches and then discharged as waste liquor.
S6 purification of crude potassium bromide:
adding 1900kg of hot water with the temperature of 60 ℃ into 2110kg of crude potassium bromide, adding 10kg of second activated carbon after dissolution, stirring for 0.5h, and filtering to remove the second activated carbon; and (3) carrying out reduced pressure distillation (the vacuum degree is less than or equal to-0.08 MP) to remove water, thus obtaining 1850kg of second recovered water, cooling the rest to 10 ℃ for crystallization, then carrying out centrifugal separation on solid and liquid, wherein the liquid component is second potassium bromide mother liquor, the second potassium bromide mother liquor and second active carbon can be added into a potassium bromide crude product together, the second potassium bromide mother liquor is reused as a waste liquid for discharge in 18-22 batches, and the solid component is dried in vacuum to obtain 1890kg of potassium bromide white powder, wherein the purity of the potassium bromide is 94.7wt% by detection.
The yield of the 10-methoxyiminostilbene prepared by the scheme of the application is up to more than 91wt%, methanol is recovered from a water layer for recycling through a recovery step, potassium ion mother liquor is neutralized and subjected to decolorization, reduced pressure distillation, crystallization and purification, potassium ions are recovered to obtain potassium bromide, the purity is up to more than 94wt%, and the potassium bromide can be sold; the first recovered water and the second recovered water can be recycled, the equipment used in the recovery step is simple, and the equipment cost is low; thereby reducing the discharge amount of sewage in the production process of the 10-methoxyiminostilbene and saving the production cost.
The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.
Claims (8)
1. A preparation method of 10-methoxyiminostilbene comprises a feeding step, a reaction step, a water washing step and a crystallization step, wherein materials in the feeding step comprise a mixed solvent of 10, 11-dibromoiminodibenzyl, potassium hydroxide, methanol and an aromatic solvent, and the water washing step comprises adding water for layering and separating an organic layer and a water layer; the method is characterized in that: also comprises a recycling step, wherein the recycling step comprises the following steps:
and (3) recovery of methanol: distilling the water layer to obtain methanol recovery liquid and potassium ion mother liquor;
neutralizing: adding hydrobromic acid into the potassium ion mother liquor, and adjusting the pH value to 6-7;
and (3) decoloring: adding first active carbon after neutralization, heating for decolorization, and filtering to remove the first active carbon;
and (3) reduced pressure distillation: distilling the components to obtain a distillate waste liquid, and distilling the components to obtain first recovered water to obtain a potassium bromide solution;
and (3) crystallization: cooling and crystallizing the potassium bromide solution, and separating to obtain a potassium bromide crude product and a first potassium bromide mother solution;
and (5) purifying a crude potassium bromide product.
2. The method for preparing 10-methoxyiminostilbene according to claim 1, wherein the method comprises the following steps: in the step of recovering the methanol, normal pressure distillation and dehydration by a supergravity bed are adopted to obtain a methanol recovery solution and a potassium ion mother solution.
3. The method for preparing 10-methoxyiminostilbene according to claim 1, wherein the method comprises the following steps: and after cooling and crystallizing the potassium bromide solution, centrifugally separating to obtain a potassium bromide crude product and a first potassium bromide mother solution.
4. The method for preparing 10-methoxyiminostilbene according to claim 3, wherein the method comprises the following steps: and adding the first potassium bromide mother liquor and the first active carbon together in the decoloring process of the first potassium bromide mother liquor obtained by reduced pressure distillation.
5. The method of claim 1, wherein the preparation of 10-methoxyiminostilbene is characterized in that: and the purification step of the potassium bromide crude product comprises the steps of adding second activated carbon and water into the potassium bromide crude product, heating, filtering to remove the second activated carbon, distilling under reduced pressure to remove water to obtain second recovered water, cooling and crystallizing the rest part, centrifuging to separate solid and liquid, and drying the solid in vacuum to obtain potassium bromide, wherein the liquid is second potassium bromide mother liquor.
6. The method of claim 5, wherein the step of preparing 10-methoxyiminostilbene is as follows: and the second potassium bromide mother liquor replaces water and is added together with the second active carbon.
7. The method for preparing 10-methoxyiminostilbene according to claim 4, wherein the method comprises the following steps: 8-12 batches of the first potassium bromide mother liquor are mechanically used to form waste liquor, and the waste liquor is discharged.
8. The method for preparing 10-methoxyiminostilbene according to claim 6, wherein the method comprises the following steps: and the second potassium bromide mother liquor is mechanically used for 18-22 batches and then becomes waste liquor to be discharged.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116354884A (en) * | 2023-03-02 | 2023-06-30 | 浙江华洋药业有限公司 | High-purity 10-methoxy iminostilbene and high-yield preparation method thereof |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101423496A (en) * | 2008-12-02 | 2009-05-06 | 浙江九洲药业股份有限公司 | Chemical synthesis method of 10-methoxyl-5H-dibenz[b,f]azapine |
| CN102807528A (en) * | 2012-08-07 | 2012-12-05 | 常州华生精细化工有限公司 | Preparation method of 10-methoxy iminostilbene |
| CN104072371A (en) * | 2013-03-29 | 2014-10-01 | 池银萍 | Preparation method of dimethyl phthalate (DMP) |
| CN105566223A (en) * | 2014-10-17 | 2016-05-11 | 中国石油化工股份有限公司 | Crude iminostilbene product recrystallization method |
| CN106467491A (en) * | 2015-08-15 | 2017-03-01 | 浙江华洲药业有限公司 | A kind of preparation method of 10- methoxyl group -5H- dibenzo [b, f] azepine * |
| CN107915665A (en) * | 2017-11-15 | 2018-04-17 | 寿光富康制药有限公司 | A kind of preparation method of thermo-sensitive material D 8 |
-
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- 2022-05-14 CN CN202210523718.3A patent/CN114957122A/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101423496A (en) * | 2008-12-02 | 2009-05-06 | 浙江九洲药业股份有限公司 | Chemical synthesis method of 10-methoxyl-5H-dibenz[b,f]azapine |
| CN102807528A (en) * | 2012-08-07 | 2012-12-05 | 常州华生精细化工有限公司 | Preparation method of 10-methoxy iminostilbene |
| CN104072371A (en) * | 2013-03-29 | 2014-10-01 | 池银萍 | Preparation method of dimethyl phthalate (DMP) |
| CN105566223A (en) * | 2014-10-17 | 2016-05-11 | 中国石油化工股份有限公司 | Crude iminostilbene product recrystallization method |
| CN106467491A (en) * | 2015-08-15 | 2017-03-01 | 浙江华洲药业有限公司 | A kind of preparation method of 10- methoxyl group -5H- dibenzo [b, f] azepine * |
| CN107915665A (en) * | 2017-11-15 | 2018-04-17 | 寿光富康制药有限公司 | A kind of preparation method of thermo-sensitive material D 8 |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN116354884A (en) * | 2023-03-02 | 2023-06-30 | 浙江华洋药业有限公司 | High-purity 10-methoxy iminostilbene and high-yield preparation method thereof |
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