CN111004205A - Synthetic method for preparing piperonyl butoxide under catalysis of composite alkali - Google Patents
Synthetic method for preparing piperonyl butoxide under catalysis of composite alkali Download PDFInfo
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- CN111004205A CN111004205A CN201911395090.8A CN201911395090A CN111004205A CN 111004205 A CN111004205 A CN 111004205A CN 201911395090 A CN201911395090 A CN 201911395090A CN 111004205 A CN111004205 A CN 111004205A
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- dichloromethane
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D317/00—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms
- C07D317/08—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3
- C07D317/44—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3 ortho- or peri-condensed with carbocyclic rings or ring systems
- C07D317/46—Heterocyclic compounds containing five-membered rings having two oxygen atoms as the only ring hetero atoms having the hetero atoms in positions 1 and 3 ortho- or peri-condensed with carbocyclic rings or ring systems condensed with one six-membered ring
- C07D317/48—Methylenedioxybenzenes or hydrogenated methylenedioxybenzenes, unsubstituted on the hetero ring
- C07D317/50—Methylenedioxybenzenes or hydrogenated methylenedioxybenzenes, unsubstituted on the hetero ring with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to atoms of the carbocyclic ring
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
- B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
- B01J31/26—Catalysts comprising hydrides, coordination complexes or organic compounds containing in addition, inorganic metal compounds not provided for in groups B01J31/02 - B01J31/24
Abstract
A process for preparing piperonyl-piperidine by catalysis of composite alkali includes such steps as using N-methylpyrrolidone as solvent medium, pyrocatechol and dihaloalkane as raw materials, azeotropic reaction of dichloromethane with the water generated by reaction, water separation, and reflux of dichloromethane to reactor.
Description
Technical Field
The invention relates to a synthetic method for preparing piperonyl butoxide under the catalysis of a composite base.
Background
1, 3-methylenedioxybenzene, also known as piperonyl, is a light yellow oily liquid, is soluble in most organic solvents, but insoluble in water, has a density slightly higher than that of water, is an important organic synthesis intermediate, is used for perfumes, cosmetics, medicines, pesticide intermediates and the like, and can be used for synthesizing Milnacanthus fulgidus (Miloxacin), Oxolinic acid (Oxolinic acid) and the like in the medical industry.
Methods for the synthesis of piperonyl cyclamate have been mentioned in a number of scientific documents.
French patent 1502914 describes the reaction of catechol with methylene chloride at a temperature of about 120 to 130 ℃ in the presence of a highly polar aprotic solvent such as dimethyl sulfoxide (DMSO) to form piperonyl butoxide.
An earlier synthesis process is taught by cornforth in its patent GB1097270, with dimethyl sulfoxide as solvent, in a strictly controlled anhydrous and oxygen-free environment, with a 91% yield of dichloromethane added dropwise to catechol-sodium hydroxide solution. After the reaction is finished, products can be recovered by the traditional methods of ether extraction, vacuum rectification, steam distillation and the like. The process is very demanding because of the need to strictly control the absence of water and oxygen and avoid excessive oxidation of catechol in strong alkaline environments. Under the common conditions, trovabang adds a potassium hydroxide solution into a mixed solution of pyrocatechol, dichloromethane and dimethyl sulfoxide, controls the reaction temperature to be 80-95 ℃, and has the yield of only 57.2%.
As described above, although it is necessary to synthesize piperonyl butoxide in an alkaline environment, pyrocatechol is excessively oxidized in a strongly alkaline environment, and the yield is lowered. The methods described above all use dimethyl sulfoxide as solvent, and compared with other strongly polar aprotic solvents such as dimethylformamide or dimethylacetamide, better catechol conversion rate and selectivity of piperonyl can be obtained. However, dimethyl sulfoxide is unstable at high temperatures, decomposes at 100 ℃ and, in the presence of alkali halides, lowers the decomposition temperature further to 50 ℃. Under the existing synthesis conditions, the decomposition of dimethyl sulfoxide tends to be out of control, so that the danger of explosion is caused. In addition, dimethyl sulfoxide has low thermal stability, so that it is difficult to recover dimethyl sulfoxide by distillation or rectification, and the dimethyl sulfoxide needs to be recovered at a low temperature under a high vacuum degree. However, even then it is difficult to avoid decomposition of dimethyl sulfoxide and produce a particularly unpleasant and toxic thiol by-product which is difficult to handle.
And a novel synthesis method is introduced in patent CN 05334A. NMP, which is also a strong polar aprotic solvent, is used as a solvent, and although it is reported in literature that NMP decomposes 50% to 70% in a strong alkaline environment of 4% potassium hydroxide for 8 hours, NMP is much more stable than DMSO and DMF in a weak alkaline environment, such as 140 ℃, PH = 8-10.
Disclosure of Invention
The invention aims to provide a synthesis method for preparing piperonyl butoxide under the catalysis of composite alkali, which adopts the composite alkali as a catalyst and can reduce the temperature required by the reaction, thereby reducing the solvent decomposition phenomenon caused by high temperature.
The technical scheme adopted for achieving the purpose is that the synthesis method for preparing the piperonyl butoxide by the catalysis of the composite alkali comprises the following steps: (1) firstly, adding solid catechol and N-methyl pyrrolidone solvent into a three-mouth bottle, introducing nitrogen to replace air in the bottle, sealing, heating and melting in an oil bath at 140 ℃, and stirring to obtain a catechol solution; (2) adding a composite base catalyst and an N-methyl pyrrolidone solvent into a four-mouth bottle, introducing nitrogen to replace air in the bottle, and introducing a tail gas pipe into the N-methyl pyrrolidone solvent for absorption; (3) raising the external temperature of the oil bath, when the internal temperature in the four-mouth bottle reaches 140 ℃, dropwise adding catechol solution and dichloromethane into the bottle at the same time, wherein the dropwise adding time lasts for 4.5h, and during the dropwise adding, an azeotrope of dichloromethane and water is heated and volatilized, and the azeotrope is condensed by a serpentine condenser tube and then flows back to a constant-pressure dropping funnel; (4) adjusting a valve of a constant-pressure dropping funnel, controlling the reflux speed of dichloromethane, always maintaining the internal temperature of the four-mouth bottle to be not lower than 135 ℃, continuously dropping dichloromethane and maintaining the internal temperature to reflux for 2 hours after the dropwise addition of the catechol solution is finished, closing stirring after the reaction is finished, stopping the reaction, cooling to room temperature, and performing suction filtration to realize solid-liquid separation; (5) washing the separated composite alkali salt with dichloromethane, drying, dissolving in water, adsorbing and decoloring with activated carbon, adjusting pH to be neutral with hydrochloric acid, evaporating, recrystallizing and drying to obtain crude salt; (6) mixing the liquid obtained by solid-liquid separation with dichloromethane for washing the composite alkali salt to form a piperonyl chloride mother liquor, weighing and detecting, and then carrying out normal pressure or reduced pressure rectification to complete separation and purification of dichloromethane, water, piperonyl chloride, N-methylpyrrolidone and heavy components.
The molar ratio of the catechol to the N-methyl pyrrolidone is 1/4-1/10.
The composite base catalyst comprises inorganic base and organic base, wherein the inorganic base comprises alkali metal carbonate, alkaline earth metal oxide and silicate; the alkali metal carbonate is selected from one or more of potassium carbonate, sodium carbonate, lithium carbonate and cesium carbonate; the alkaline earth metal oxide is selected from one or more of magnesium oxide, calcium oxide and barium oxide; the silicate is sodium silicate or potassium silicate; the organic base is selected from one or more of sodium methoxide, potassium ethoxide, sodium ethoxide, potassium tert-butoxide and sodium tert-butoxide.
Advantageous effects
Compared with the prior art, the invention has the following advantages.
The invention has the advantages that the method takes catechol and dichloromethane as raw materials to synthesize the piperonyl butoxide, further researches the prior art, reduces the reaction temperature, reduces the consumption of solvent, improves the reaction selectivity and reduces the production cost by using a novel composite base catalyst.
Drawings
The present invention will be described in further detail with reference to the accompanying drawings.
FIG. 1 is a schematic diagram of the preparation process of the present invention.
Detailed Description
The invention is further described with reference to specific embodiments and the accompanying drawings.
A synthetic method for preparing piperonyl butoxide under the catalysis of composite alkali comprises the following steps: (1) firstly, adding solid catechol and N-methyl pyrrolidone solvent into a three-mouth bottle, introducing nitrogen to replace air in the bottle, sealing, heating and melting in an oil bath at 140 ℃, and stirring to obtain a catechol solution; (2) adding a composite base catalyst and an N-methyl pyrrolidone solvent into a four-mouth bottle, introducing nitrogen to replace air in the bottle, and introducing a tail gas pipe into the N-methyl pyrrolidone solvent for absorption; (3) raising the external temperature of the oil bath, when the internal temperature in the four-mouth bottle reaches 140 ℃, dropwise adding catechol solution and dichloromethane into the bottle at the same time, wherein the dropwise adding time lasts for 4.5h, and during the dropwise adding, an azeotrope of dichloromethane and water is heated and volatilized, and the azeotrope is condensed by a serpentine condenser tube and then flows back to a constant-pressure dropping funnel; (4) adjusting a valve of a constant-pressure dropping funnel, controlling the reflux speed of dichloromethane, always maintaining the internal temperature of the four-mouth bottle to be not lower than 135 ℃, continuously dropping dichloromethane and maintaining the internal temperature to reflux for 2 hours after the dropwise addition of the catechol solution is finished, closing stirring after the reaction is finished, stopping the reaction, cooling to room temperature, and performing suction filtration to realize solid-liquid separation; (5) washing the separated composite alkali salt with dichloromethane, drying, dissolving in water, adsorbing and decoloring with activated carbon, adjusting pH to be neutral with hydrochloric acid, evaporating, recrystallizing and drying to obtain crude salt; (6) mixing the liquid obtained by solid-liquid separation with dichloromethane for washing the composite alkali salt to form a piperonyl chloride mother liquor, weighing and detecting, and then carrying out normal pressure or reduced pressure rectification to complete separation and purification of dichloromethane, water, piperonyl chloride, N-methylpyrrolidone and heavy components.
The molar ratio of the catechol to the N-methyl pyrrolidone is 1/4-1/10.
The composite base catalyst comprises inorganic base and organic base, wherein the inorganic base comprises alkali metal carbonate, alkaline earth metal oxide and silicate; the alkali metal carbonate is selected from one or more of potassium carbonate, sodium carbonate, lithium carbonate and cesium carbonate; the alkaline earth metal oxide is selected from one or more of magnesium oxide, calcium oxide and barium oxide; the silicate is sodium silicate or potassium silicate; the organic base is selected from one or more of sodium methoxide, potassium ethoxide, sodium ethoxide, potassium tert-butoxide and sodium tert-butoxide.
The preparation method of the composite alkali catalyst comprises the steps of adding composite alkali into a beaker, adding deionized water into the composite alkali, adding sulfhydryl chitosan into the composite alkali, standing at room temperature and drying to obtain the composite alkali catalyst.
Adding chitosan, N-hydroxy-7-azabenzotriazole and distilled water into a reactor, uniformly stirring, adding 2-mercapto-4-methyl-5-thiazoleacetic acid and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride, adjusting the pH of a reaction solution to 5 by using 1mol/L sodium hydroxide, reacting at room temperature for 4 hours, adding absolute ethyl alcohol, filtering, drying at 60 ℃ under reduced pressure for 10 hours, grinding, and storing at 5 ℃ at low temperature; the weight ratio of the chitosan to the N-hydroxy-7-azabenzotriazole to the distilled water is 1: 0.6: 20; the weight ratio of the chitosan to the 2-mercapto-4-methyl-5-thiazoleacetic acid is 1: 2.4; the molar ratio of the 2-mercapto-4-methyl-5-thiazoleacetic acid to the 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride is 1: 1.05; the weight ratio of the chitosan to the absolute ethyl alcohol is 1: 12.
according to the invention, the compound alkali is used as a catalyst, the temperature required by the reaction can be reduced, so that the solvent decomposition phenomenon caused by high temperature is reduced, the molar ratio of catechol/potassium carbonate in the synthesis is 1/1-1/2, calcium oxide, sodium silicate and cesium carbonate for promoting alkalinity are added, the molar ratio of catechol/potassium carbonate is further optimized to 1/1.05, so that the use amount of potassium carbonate is reduced, the molar ratio of catechol/N-methylpyrrolidone is 1/4-1/10, and is further preferably 1/6.5, wherein half of the solvent is added into a three-mouth bottle to help catechol to melt, so that the catechol cannot be solidified in a peristaltic pump pipeline in the dropping process. The molar ratio of catechol to dichloromethane is 1/2-1/8, the preference is 1/6, the catalytic activity of the composite base is high, and the conversion rate of catechol and the purity of the product are further improved. The ratio of sodium methoxide to inorganic base is 1/40-1/15, and the ratio of sodium methoxide to inorganic base is 1/20.
Example 1
63.78g of composite alkali is added into a beaker, wherein the composite alkali contains 59.78 g of inorganic alkali (the mass ratio of potassium carbonate, calcium oxide, sodium silicate and cesium carbonate in the inorganic alkali is 45:1/2: 1/2:2 × 10)-6) And 4g of sodium methoxide, 320ml of deionized water is added, 287g of sulfhydryl chitosan is added, the mixture is kept stand for 10 hours at room temperature and dried for 12 hours at 120 ℃, and the composite base catalyst is prepared.
The preparation method of the mercapto chitosan comprises the following steps: adding chitosan, N-hydroxy-7-azabenzotriazole and distilled water into a reactor, stirring uniformly, adding 2-mercapto-4-methyl-5-thiazoleacetic acid and 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride, adjusting the pH of a reaction solution to 5 by using 1mol/L sodium hydroxide, reacting at room temperature for 4h, adding absolute ethyl alcohol, filtering, drying at 60 ℃ under reduced pressure for 10h, grinding, and storing at 5 ℃ at low temperature; the weight ratio of the chitosan to the N-hydroxy-7-azabenzotriazole to the distilled water is 1: 0.6: 20; the weight ratio of the chitosan to the 2-mercapto-4-methyl-5-thiazoleacetic acid is 1: 2.4; the molar ratio of the 2-mercapto-4-methyl-5-thiazoleacetic acid to the 1- (3-dimethylaminopropyl) -3-ethylcarbodiimide hydrochloride is 1: 1.05; the weight ratio of the chitosan to the absolute ethyl alcohol is 1: 12.
adding the prepared composite base into a four-mouth bottle, adding 128.90g of NMP (1.300 mol), adding 44.37g (0.403 mol) of catechol, 129.91g of NMP (1.310 mol) and 141.72g of dichloromethane (1.669 mol) during dripping of catechol solution, adding 63.63g (0.749 mol) of dichloromethane, and detecting by gas chromatography to synthesize 46.14g of piperonyl rings (0.378 mol) and leave 0.38g of catechol unreacted. The conversion rate of catechol is 99.14%, the selectivity of piperonyl is 94.57%, and the synthesis yield is 93.76%.
Example 2
The preparation of the catalyst of example 1 was repeated by charging 62.63 g of the above prepared complex base containing 59.63 g of inorganic base (the mass ratio of potassium carbonate, magnesium oxide, potassium silicate and barium chloride in the inorganic base was 45:1/2: 1/2: 2X 10) into a four-necked flask-6) And 3g of a sodium methoxide composite catalyst, 128.89g of NMP (1.300 mol) was added, 44.23g (0.402 mol) of catechol, 129.26g of NMP (1.304 mol) and 140.14g of dichloromethane (1.650 mol) were added during the dropwise addition of the catechol solution, 64.53g (0.760 mol) of dichloromethane was added, 47.07g of pepper rings (0.385 mol) were synthesized, and 0.37g of catechol remained unreacted. The conversion rate of catechol is 99.16%, the selectivity of piperonyl is 95.49% and the synthesis yield is 94.69%.
Example 3
The preparation of the catalyst of example 1 was repeated by adding 64.90 g of the above prepared complex base containing 62.90 g of inorganic base (the mass ratio of potassium carbonate, calcium oxide, sodium silicate and copper chloride in the inorganic base was 45:1/2: 1/2: 2X 10) to a four-necked flask-6) And 2g of sodium methoxide, and 136.84g of NMP (1.380 mol) were added thereto, and a catechol solution was added dropwiseDuring the synthesis, 46.69g of catechol (0.424 mol), 127.88g of NMP (1.391 mol) and 147.71g of dichloromethane (1.739 mol) are added, 68.35g of dichloromethane (0.805 mol) is added, and 48.11 g of piperonyl-containing rings (0.394 mol) are synthesized by gas chromatography detection, wherein all the catechol reacts, namely the conversion rate of the catechol is 100%, the selectivity of the piperonyl-containing rings is 92.91%, and the synthesis yield is 92.91%.
Example 4
20.62 g of composite alkali is added into the beaker, and the composite alkali contains 20.12 g of inorganic alkali (the mass ratio of potassium carbonate, calcium oxide, sodium silicate and cesium carbonate in the inorganic alkali is 45:1/2: 1/2:2 × 10)-6) And 0.5 g of sodium methoxide, adding 105ml of deionized water, adding 95g of sulfhydryl chitosan, standing at room temperature for 10h, and drying at 120 ℃ for 12h to obtain the composite alkali catalyst. The preparation method of the mercapto chitosan is the same as that of example 1.
The complex base prepared above was charged into a four-necked flask, 42.04g of NMP (0.424 mol) was added, 14.27g (0.130 mol) of catechol, 41.92g (0.423 mol) of NMP and 43.73g of dichloromethane (0.515 mol) were added during the dropwise addition of the catechol solution, 22.31g (0.263 mol) of dichloromethane was added, 13.80g of piperonyl chloride (0.113 mol) was co-synthesized by gas chromatography, and 0.10g of catechol remained unreacted. The conversion rate of catechol is 98.56%, the selectivity of piperonyl is 91.82%, and the synthesis yield is 90.20%.
Comparative examples
18.87 g of potassium carbonate (0.163 mol) and 42.04g of NMP (0.424 mol) were charged into a four-necked flask, and 14.27g (0.130 mol) of catechol and 41.92g of NMP (0.423 mol) were added together with 43.73g of dichloromethane (0.515 mol) during the dropwise addition of the catechol solution, and 22.31g (0.263 mol) of dichloromethane was added, and 13.80g of piperonyl cyclobenzene (0.113 mol) was synthesized together by gas chromatography, and 0.10g of catechol remained unreacted. The conversion rate of catechol is 98.29%, the selectivity of piperonyl chloride is 87.82%, and the synthesis yield is 87.20%.
Claims (3)
1. A synthetic method for preparing piperonyl butoxide under the catalysis of composite alkali is characterized by comprising the following steps: (1) firstly, adding solid catechol and N-methyl pyrrolidone solvent into a three-mouth bottle, introducing nitrogen to replace air in the bottle, sealing, heating and melting in an oil bath at 140 ℃, and stirring to obtain a catechol solution; (2) adding a composite base catalyst and an N-methyl pyrrolidone solvent into a four-mouth bottle, introducing nitrogen to replace air in the bottle, and introducing a tail gas pipe into the N-methyl pyrrolidone solvent for absorption; (3) raising the external temperature of the oil bath, when the internal temperature in the four-mouth bottle reaches 140 ℃, dropwise adding catechol solution and dichloromethane into the bottle at the same time, wherein the dropwise adding time lasts for 4.5h, and during the dropwise adding, an azeotrope of dichloromethane and water is heated and volatilized, and the azeotrope is condensed by a serpentine condenser tube and then flows back to a constant-pressure dropping funnel; (4) adjusting a valve of a constant-pressure dropping funnel, controlling the reflux speed of dichloromethane, always maintaining the internal temperature of the four-mouth bottle to be not lower than 135 ℃, continuously dropping dichloromethane and maintaining the internal temperature to reflux for 2 hours after the dropwise addition of the catechol solution is finished, closing stirring after the reaction is finished, stopping the reaction, cooling to room temperature, and performing suction filtration to realize solid-liquid separation; (5) washing the separated composite alkali salt with dichloromethane, drying, dissolving in water, adsorbing and decoloring with activated carbon, adjusting pH to be neutral with hydrochloric acid, evaporating, recrystallizing and drying to obtain crude salt; (6) mixing the liquid obtained by solid-liquid separation with dichloromethane for washing the composite alkali salt to form a piperonyl chloride mother liquor, weighing and detecting, and then carrying out normal pressure or reduced pressure rectification to complete separation and purification of dichloromethane, water, piperonyl chloride, N-methylpyrrolidone and heavy components.
2. The synthetic method for preparing piperonyl butoxide by using the composite base catalyst as claimed in claim 1, wherein the molar ratio of catechol to N-methylpyrrolidone is 1/4-1/10.
3. The synthesis method for preparing piperonyl by catalysis of composite alkali as claimed in claim 1, wherein the composite alkali catalyst includes inorganic alkali and organic alkali, the inorganic alkali includes alkali metal carbonate, alkaline earth metal oxide and silicate; the alkali metal carbonate is selected from one or more of potassium carbonate, sodium carbonate, lithium carbonate and cesium carbonate; the alkaline earth metal oxide is selected from one or more of magnesium oxide, calcium oxide and barium oxide; the silicate is sodium silicate or potassium silicate; the organic base is selected from one or more of sodium methoxide, potassium ethoxide, sodium ethoxide, potassium tert-butoxide and sodium tert-butoxide.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115057841A (en) * | 2022-03-24 | 2022-09-16 | 万华化学集团股份有限公司 | Method for preparing 1, 2-methylenedioxybenzene |
| CN115925671A (en) * | 2023-02-20 | 2023-04-07 | 河北海力恒远新材料股份有限公司 | Method for purifying piperitone |
Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1205334A (en) * | 1997-05-08 | 1999-01-20 | 伯里加德意大利公司 | Process for preparation of aromatic compounds containing heterocyclic system |
| CN1907980A (en) * | 2006-08-11 | 2007-02-07 | 贵阳海丰精细化工有限公司 | Method for synthesizing dihydrosafrole |
| CN105754016A (en) * | 2016-03-09 | 2016-07-13 | 沈阳药科大学 | Novel bioadhesive thiolated chitosan synthesis method |
| CN106397387A (en) * | 2016-09-20 | 2017-02-15 | 苏州弘森药业股份有限公司 | Method for preparing pepper ring |
| WO2017158404A1 (en) * | 2016-03-12 | 2017-09-21 | Anthea Aromatics Private Limited | An improved method for the preparation of alkylenedioxybenzene compounds |
-
2019
- 2019-12-30 CN CN201911395090.8A patent/CN111004205A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1205334A (en) * | 1997-05-08 | 1999-01-20 | 伯里加德意大利公司 | Process for preparation of aromatic compounds containing heterocyclic system |
| CN1907980A (en) * | 2006-08-11 | 2007-02-07 | 贵阳海丰精细化工有限公司 | Method for synthesizing dihydrosafrole |
| CN105754016A (en) * | 2016-03-09 | 2016-07-13 | 沈阳药科大学 | Novel bioadhesive thiolated chitosan synthesis method |
| WO2017158404A1 (en) * | 2016-03-12 | 2017-09-21 | Anthea Aromatics Private Limited | An improved method for the preparation of alkylenedioxybenzene compounds |
| CN106397387A (en) * | 2016-09-20 | 2017-02-15 | 苏州弘森药业股份有限公司 | Method for preparing pepper ring |
Non-Patent Citations (1)
| Title |
|---|
| 卫小广: "合成洋茉莉醛的工艺研究", 《中国优秀博硕士学位论文全文数据库(硕士)工程科技Ⅰ辑》, no. 3, 15 March 2015 (2015-03-15), pages 15 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115057841A (en) * | 2022-03-24 | 2022-09-16 | 万华化学集团股份有限公司 | Method for preparing 1, 2-methylenedioxybenzene |
| CN115057841B (en) * | 2022-03-24 | 2023-09-19 | 万华化学集团股份有限公司 | Method for preparing 1, 2-methylenedioxybenzene |
| CN115925671A (en) * | 2023-02-20 | 2023-04-07 | 河北海力恒远新材料股份有限公司 | Method for purifying piperitone |
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