CN110627619A - Preparation method of pinacol - Google Patents
Preparation method of pinacol Download PDFInfo
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- CN110627619A CN110627619A CN201910938415.6A CN201910938415A CN110627619A CN 110627619 A CN110627619 A CN 110627619A CN 201910938415 A CN201910938415 A CN 201910938415A CN 110627619 A CN110627619 A CN 110627619A
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/36—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring increasing the number of carbon atoms by reactions with formation of hydroxy groups, which may occur via intermediates being derivatives of hydroxy, e.g. O-metal
- C07C29/38—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring increasing the number of carbon atoms by reactions with formation of hydroxy groups, which may occur via intermediates being derivatives of hydroxy, e.g. O-metal by reaction with aldehydes or ketones
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Abstract
The invention discloses a preparation method of pinacol, which comprises the steps of adding a stannic chloride source solution into an acetone-isopropanol reaction solution, introducing argon for 10 minutes under magnetic stirring, starting an ultraviolet lamp source, and starting a photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction to prepare pinacol; controlling the reaction temperature to be 20-50 ℃ and the reaction time to be 5-36 hours; standing at low temperature, separating out pinacol crystal, filtering to obtain pinacol product, and recycling the filtrate. The method has the advantages of simple process, high selectivity, high activity, high yield, low cost, environmental friendliness and the like, and the purity of the pinacol reaches 98%.
Description
Technical Field
The invention relates to the synthesis of pinacol (tetramethylglycol), in particular to a method for preparing pinacol by catalyzing isopropanol dehydrogenation-acetone hydrogenation coupling by using a tin-isopropanol or tin-acetone complex prepared in situ as a photocatalyst under illumination.
Technical Field
The pinacol is widely applied to synthesis of fine chemical products such as high molecular polymers, pesticides, medicines and the like, and has wide application prospect. Pinacols are usually obtained by reductive coupling of carbonyl compounds with the aid of metal reagents or metal complexes, such as the McMurry reaction (ref: j.e.mcmurry, chem.rev.1989,89,1513; a.fiirstner, b.bogdanovic, Angew chem.int.ed.1996,35,2442). McMurry reaction generally uses reduced coupling carbonyl compounds (stoichiometric ratio of titanium to ketone) of strongly reduced titanium obtained by in situ reaction to form a metal-pinacol intermediate first, under low temperature conditionsPinacol is produced and further reacted under high temperature conditions to produce olefins (ref: k.g.pierce, m.a.barteau, j.org.chem.1995,60,2405; m.stahl, u.pidun, g.frenking, angew.chem.int.ed.1997,36,2234; r.dam, m.malinolski, i.westdorp, h.j.geise, j.org.chem.1981,46,2407; t.a.lipski, m.a.hilfiker, s.g.nelson, j.g.chem., 1997,62, 4566). The research on the McMurry reaction has mainly focused on the modulation and improvement of the catalyst and on the expansion of the range of applications, such as NbCl5/NaAlH4Catalysts such as Mg-Hg and Zn-Cu are used in the McMurry reaction. Recently, SnCl has been reported in the literature4The McMurry reaction can be smoothly carried out by using a Zn system as a catalyst, and Sn (II) obtained by in-situ reduction of Zn has strong reducibility (G.K.Pathe, N.K.Kondaru, I.Parveen, N.Ahmed, RSC adv.,2015,5, 83512-. At present, pinacol is industrially prepared by reduction of acetone, and Mg chips and HgCl are used in the reaction process2And benzene, which is not environmentally friendly.
The photocatalytic reaction is usually carried out at normal temperature and normal pressure, the condition is mild, the operation is simple, secondary pollution cannot be generated, and the method is a green synthesis technology. At present, many reports on photocatalytic organic synthesis exist, but the photocatalytic organic synthesis is not widely applied in practice because of low reaction selectivity due to the free radical characteristics of the photocatalytic reaction. Shanxi coal chemistry research in 2014 reports that isopropanol dehydrogenation-acetone hydrogenation coupling is realized in isopropanol and acetone aqueous solution by taking sodium tantalate as a catalyst to obtain a product pinacol (B.Y.Cao, J.Zhang, J.H.ZHao, Z.J.Wang, P.J.Yang, H.X.Zhang, L.Li, Z.P.Zhu, ChemCATchem 2014,6,1673-. However, the catalyst structure and the reaction system need to be further optimized, and the reaction efficiency needs to be further improved.
Disclosure of Invention
The invention aims to provide a method for preparing pinacol by photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling, which has the advantages of high yield, high purity, low cost, no environmental pollution and simple process.
The invention provides a preparation method of pinacol, which utilizes SnCl4As catalyst, isopropanol and acetone as raw materials, Sn4+Forming a photoresponse complex with isopropanol or acetone, reducing tetravalent tin into low-valent tin in situ under the irradiation of ultraviolet light, and catalyzing isopropanol dehydrogenation-acetone hydrogenation coupling to prepare pinacol. The invention has simple process method, low catalyst cost and highest product selectivity of 98.2 percent; isopropanol and acetone are reaction raw materials, no solvent is needed, the separation is easy, and the product purity can reach 98%; the reaction liquid can be recycled, is environment-friendly and energy-saving, and is a high-efficiency green method for synthesizing pinacol. The reaction process is as follows:
the technical scheme of the invention is as follows:
SnCl is added according to the volume ratio of 100:0.05-0.154Adding acetone-isopropanol reaction liquid into the source solution, introducing argon gas for 10 minutes under magnetic stirring, removing oxygen in the system, starting an ultraviolet lamp, controlling the reaction temperature to be 20-50 ℃, reacting for 5-36 hours, precipitating pinacol by a static crystallization method, filtering to obtain a product, and continuously recycling the filtrate.
The acetone-isopropanol reaction solution is a reaction solution in which the volume ratio of acetone to isopropanol is 100:0-0:100, preferably 40:60-60:40, and more preferably 50: 50.
The SnCl4The source solution is SnCl with the concentration of 100mg/ml4Isopropanol or acetone solution, preferably SnCl4Acetone solution.
The power of the ultraviolet lamp is 200-500W.
The reaction temperature is preferably 20-30 ℃; the reaction time is preferably 9 to 20 hours.
Compared with the prior art, the invention has the following advantages: 1. by SnCl4As a catalyst, Sn4+Forming a photoresponse complex with isopropanol or acetone and reducing the photoresponse complex into low-valent tin in situ under illumination for further photocatalytic reaction, wherein the catalyst is low in price. 2. The isopropanol and the acetone are used as raw materials, so that the method is pollution-free, convenient to operate and capable of recycling the raw materials. 3. Simple technological process and catalysisThe agent has the advantages of stable performance, high activity, low price, environmental protection and the like. 4. The reaction does not need a solvent, the separation of the product pinacol and the isopropanol-acetone reaction liquid is simple, the product selectivity is high, and the purity is as high as more than 98%.
Description of the drawings:
FIG. 1 gas chromatogram of isopropyl alcohol-acetone photocatalytic reaction solution of example 1
FIG. 2 is the electron bombardment mass spectrum of the product pinacol
Detailed Description
The invention is further illustrated by the following examples, which are intended only for a better understanding of the contents of the invention and do not limit the scope of the invention.
SnCl used in examples4The source solution is SnCl with the concentration of 100mg/ml4Isopropanol or acetone solution.
Example 1
0.2ml of SnCl4Adding the acetone source solution into 200ml of isopropanol-acetone solution (volume ratio is 50:50), introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 20 ℃, and reacting for 9 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously recycled. Gas chromatographic analysis showed that the liquid phase product had a pinacol selectivity of 98.2% and a total isopropanol-acetone conversion of 29%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Example 2
0.2ml of SnCl4Adding the acetone source solution into 200ml of isopropanol-acetone solution (volume ratio is 90:10), introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 20 ℃, and reacting for 9 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously recycled. Gas chromatographic analysis shows that the selectivity of pinacol in the liquid phase product is 98% and the total conversion rate of isopropanol-acetone is 13%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Example 3
0.2ml of SnCl4Adding the acetone source solution into 200ml of isopropanol-acetone solution (volume ratio is 80:20), introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 20 ℃, and reacting for 9 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously recycled. Gas chromatographic analysis showed that the liquid phase product had a pinacol selectivity of 97.5% and an isopropanol-acetone overall conversion of 13.6%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Example 4
0.2ml of SnCl4Adding the acetone source solution into 200ml of isopropanol, introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic reaction, controlling the reaction temperature to be 20 ℃ and the reaction time to be 9 hours. After the reaction, gas chromatography analysis shows that the selectivity of pinacol in the liquid phase product is 15% and the conversion rate of isopropanol is 0.8%.
Example 5
0.2ml of SnCl4Adding the acetone source solution into 200ml of isopropanol-acetone solution (volume ratio of 20:80), introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 20 ℃, and reacting for 9 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously recycled. Gas chromatographic analysis showed that the liquid phase product had a pinacol selectivity of 66% and a total isopropanol-acetone conversion of 29%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Example 6
0.2ml of SnCl4Adding the acetone source solution into 200ml of isopropanol-acetone solution (volume ratio is 10:90), introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 20 ℃, and reacting for 9 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously recycled. The gas chromatographic analysis shows that the selectivity of pinacol in the liquid phase product is 55 percent, and the total conversion rate of isopropanol-acetoneThe content was 29%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Example 7
0.2ml of SnCl4Adding the acetone source solution into 200ml of acetone solution, introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic reaction, controlling the reaction temperature to be 20 ℃ and the reaction time to be 9 hours. After the reaction, gas chromatography analysis showed that the liquid phase product had pinacol selectivity of 5.6% and acetone conversion of 0.9%.
Example 8
0.5ml of SnCl4Adding the acetone source solution into 500ml of isopropanol-acetone solution (volume ratio is 50:50), introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 20 ℃, and reacting for 9 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously recycled. Gas chromatographic analysis showed that the liquid phase product had a pinacol selectivity of 97.5% and a total isopropanol-acetone conversion of 29%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Example 9
0.2ml of SnCl4Adding the acetone source solution into 200ml of isopropanol-acetone solution (volume ratio is 50:50), introducing argon gas for 10 minutes under magnetic stirring, starting a 500W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 20 ℃, and reacting for 9 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously recycled. Gas chromatographic analysis shows that the selectivity of pinacol in the liquid phase product is 98% and the total conversion rate of isopropanol-acetone is 36%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Example 10
0.2ml of SnCl4Adding the acetone source solution into 200ml of isopropanol-acetone solution (volume ratio is 50:50), introducing argon gas for 10 minutes under magnetic stirring, starting a 200W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 20 ℃, and reacting for 9 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously circulatedThe preparation is used. Gas chromatographic analysis showed that the liquid phase product had a pinacol selectivity of 98% and a total isopropanol-acetone conversion of 22%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Example 11
0.2ml of SnCl4Adding the acetone source solution into 200ml of isopropanol-acetone solution (volume ratio is 50:50), introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 50 ℃, and reacting for 9 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously recycled. Gas chromatography analysis showed that the liquid phase product had a pinacol selectivity of 86% and a total isopropanol-acetone conversion of 33%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Example 12
0.2ml of SnCl4Adding the acetone source solution into 200ml of isopropanol-acetone solution (volume ratio is 50:50), introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 30 ℃, and reacting for 9 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously recycled. Gas chromatographic analysis showed that the liquid phase product had a pinacol selectivity of 89% and a total isopropanol-acetone conversion of 32%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Example 13
0.2ml of SnCl4Adding the acetone source solution into 200ml of isopropanol-acetone solution (volume ratio is 50:50), introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 20 ℃, and reacting for 5 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously recycled. Gas chromatographic analysis showed that the liquid phase product had a pinacol selectivity of 98% and a total isopropanol-acetone conversion of 18%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Example 14
0.2ml of SnCl4Acetone source solution is addedAdding the solution into 200ml of isopropanol-acetone solution (volume ratio is 50:50), introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 20 ℃, and reacting for 20 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously recycled. Gas chromatographic analysis shows that the selectivity of pinacol in the liquid phase product is 98% and the total conversion rate of isopropanol-acetone is 30%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Example 15
0.2ml of SnCl4Adding the isopropanol source solution into 200ml of isopropanol-acetone solution (volume ratio is 50:50), introducing argon gas for 10 minutes under magnetic stirring, starting a 300W high-pressure mercury lamp to perform photocatalytic isopropanol dehydrogenation-acetone hydrogenation coupling reaction, controlling the reaction temperature to be 20 ℃, and reacting for 9 hours. After the reaction is finished, the pinacol is separated out by a standing crystallization method, and the filtrate is continuously recycled. Gas chromatographic analysis showed that the liquid phase product had a pinacol selectivity of 98% and a total isopropanol-acetone conversion of 16%. The purity of the pinacol can reach 98 percent through gas chromatography detection.
Claims (6)
1. A preparation method of pinacol is characterized by comprising the following steps:
SnCl is added according to the volume ratio of 100:0.05-0.154Adding acetone-isopropanol reaction liquid into the source solution, introducing argon gas for 10 minutes under magnetic stirring, removing oxygen in the system, starting an ultraviolet lamp, controlling the reaction temperature to be 20-50 ℃, reacting for 5-36 hours, precipitating pinacol by a static crystallization method, filtering to obtain a product, and continuously recycling the filtrate;
the SnCl4The source solution is SnCl with the concentration of 100mg/ml4Isopropanol or acetone solution.
2. The method according to claim 1, wherein the acetone-isopropanol reaction solution is a reaction solution in which the volume ratio of acetone to isopropanol is 40:60-60: 40.
3. The method according to claim 2, wherein the acetone-isopropanol reaction solution is a reaction solution in which the volume ratio of acetone to isopropanol is 50: 50.
4. The method as claimed in claim 1, wherein the power of the UV lamp is 200-500W.
5. The process for preparing pinacol according to claim 1, wherein the reaction temperature is 20 to 30 ℃; the reaction time is 9-20 hours.
6. The method of claim 1, wherein the SnCl is produced by the method of claim 14The source solution is SnCl4Acetone solution.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102976896A (en) * | 2012-11-29 | 2013-03-20 | 中国科学院山西煤炭化学研究所 | Method for preparing pinacol by dehydrogenation of photocatalytic isopropanol dehydrogenation and hydrogenation coupling of acetone |
| CN105536878A (en) * | 2016-01-07 | 2016-05-04 | 福州大学 | Cellulose-based composite photocatalytic material |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102976896A (en) * | 2012-11-29 | 2013-03-20 | 中国科学院山西煤炭化学研究所 | Method for preparing pinacol by dehydrogenation of photocatalytic isopropanol dehydrogenation and hydrogenation coupling of acetone |
| CN105536878A (en) * | 2016-01-07 | 2016-05-04 | 福州大学 | Cellulose-based composite photocatalytic material |
Non-Patent Citations (1)
| Title |
|---|
| 张文琴: "TiO2纳米片光催化醇氧化及其反应机理", 《中国优秀硕士学位论文全文数据库 工程科技Ⅰ辑》 * |
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