CN114108014B - Method for synthesizing pinacol by selective electroreduction coupling of active hydrogen-mediated carbonyl compound in water - Google Patents
Method for synthesizing pinacol by selective electroreduction coupling of active hydrogen-mediated carbonyl compound in water Download PDFInfo
- Publication number
- CN114108014B CN114108014B CN202010886293.3A CN202010886293A CN114108014B CN 114108014 B CN114108014 B CN 114108014B CN 202010886293 A CN202010886293 A CN 202010886293A CN 114108014 B CN114108014 B CN 114108014B
- Authority
- CN
- China
- Prior art keywords
- pinacol
- reaction
- diol
- synthesizing
- coupling
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- 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
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
Landscapes
- Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a method for synthesizing pinacol by using active hydrogen-mediated selective electroreduction coupling of carbonyl compounds in water, which is characterized in that the carbonyl compounds are used as reaction substrates and a reaction system using carbon paper as a working electrode is used for reaction, and the corresponding pinacol compounds are obtained through constant potential electrochemical selective reduction, wherein the reaction potential is-1.6 to-1.1V. The invention can realize the high-efficiency and high-selectivity synthesis of pinacol compound in a wider potential range, has higher functional group tolerance and better substrate universality, takes cheap and easily-obtained and high-efficiency carbon material as an electrode, takes green, safe and abundant water as a solvent and a hydrogen source, does not need an additional hydrogen source, has mild reaction condition, does not need heating, is simple and convenient to operate, and has easy separation of products and easy recovery of a catalyst. In addition, the invention can carry out amplification experiments in the electrocatalytic membrane reactor, and can realize the synthesis of pinacol by adopting low-cost monoalcohol and through electrochemical anodic oxidation-cathodic reduction relay catalytic reaction.
Description
Technical Field
The invention relates to the technical field of electrocatalytic synthesis of pinacol, in particular to a method for synthesizing pinacol by active hydrogen-mediated selective electroreduction coupling of carbonyl compounds in water.
Background
The formation of carbon-carbon bonds is an important method for organically synthesizing chemical construction compounds, selective reductive coupling of carbonyl compounds for synthesizing pinacol provides a feasible way for constructing carbon-carbon bonds, and the obtained pinacol products and derivatives thereof have very important application in the fields of natural products, medicines, materials, catalysis and the like, but the preparation of the pinacol by the reductive coupling of carbonyl compounds still cannot be applied on a large scale due to the restriction of the synthesis method. The methods for synthesizing pinacol so far mainly include:
(1) Traditional chemical Synthesis
Conventional chemical processes generally use far greater than stoichiometric amounts of reducing agents (Mg, zn, al, etc.), and require the addition of acidic auxiliaries (mineral acids, tiCl 4 ，ZnCl 2 Etc.). The method not only causes waste due to excessive use of metal, but also generates a large amount of reaction waste to pollute the environment, which does not meet the synthesis requirements of atomic economy and green chemistry in modern production. In recent decades, attempts have been made to optimize the process of pinacol synthesis with lanthanoid elements, metal halides, etc. as catalysts, avoiding to some extent the waste of metals. However, the cost of synthesizing these catalysts is high, and the large-scale application of the reduction coupling of carbonyl compounds is still limited.
(2) Photocatalytic process
With the deep knowledge of pinacol synthesis and the development of photocatalytic synthesis technology, researchers have found that photochemical reduction of carbonyl compounds can yield high yields of coupled products. However, the method generally uses a complex of noble metal Ir as a photocatalyst, and simultaneously needs organic amine, such as hydrazine hydrate and the like, as a proton source, which not only increases the cost for synthesizing pinacol, but also causes side reactions; meanwhile, the method has the defects of low light reaction energy utilization rate, long reaction time, poor stability of the photocatalyst, complex recycling process and the like. Therefore, there is a need to explore and develop a green, economical, efficient and catalyst stable, easy to recycle process to achieve high selectivity synthesis of pinacol.
(3) Electrocatalytic process
In recent years, the electrocatalytic organic transformation has the advantages of environmental friendliness, mild reaction conditions, high energy utilization rate, controllable reaction height and the like, is applied to organic synthesis as an important transformation means, and a plurality of important medicaments, functional materials and the like are prepared, so that effective regulation and control of product selectivity can be realized by regulating input voltage or current, and the electrocatalytic or promoted organic transformation gradually becomes one of the popular research directions in synthetic chemistry.
In early studies of pinacol coupling, acetophenone in the organic phase electrolyte could be reduced to glycol at the mercury electrode surface. Typically, organic solvents such as: the use of DMF, DMSO, etc. can make product isolation difficult; in the subsequent research, the electrolyte is replaced by the ionic liquid to relieve the problem of difficult separation of the pinacol product, but expensive ionic liquid and Pt and Hg electrodes are still important constraint factors for the mass production and synthesis of the pinacol.
In view of the defects of the synthesis method, the realization of the high-selectivity preparation of the pinacol by the electroreduction coupling of the carbonyl compound by using the medium of the aqueous electrolyte has important significance. In the aqueous electrolyte, reactions that may occur on the cathode are Hydrogen Evolution Reactions (HER) of water decomposition, reduction of carbonyl compounds to monohydric alcohols, and reductive coupling to pinacol. It is well known that alkaline electrolytes can inhibit HER to some extent, but carbonyl reduction to monohydric alcohols remains the primary competing reaction for pinacol synthesis. It is therefore necessary to find an inexpensive, efficient electrocatalyst that significantly reduces or inhibits HER or side reactions that produce monohydric alcohols in aqueous electrolytes to increase the conversion and selectivity of pinacol synthesis.
Disclosure of Invention
The invention overcomes the defects in the prior art, the use of an organic solvent can make the separation of products difficult, if the electrolyte is replaced by the ionic liquid, the problem of difficult separation of pinacol products can be solved, but expensive ionic liquid and Pt and Hg electrodes are still important constraint factors for the mass production of the pinacol, the invention provides a method for synthesizing the pinacol by selective electric reduction coupling of active hydrogen-mediated carbonyl compounds in water, the high-efficiency and high-selectivity synthesis of the pinacol compounds can be realized in a wider potential range, the high-efficiency and high-selectivity synthesis of the pinacol compounds has higher functional group tolerance and better substrate applicability, and the method uses cheap and easily available and high-efficiency carbon materials as electrodes, uses green, safe and abundant water as solvents and hydrogen sources, has mild reaction conditions, no need of heating, simple operation and easy separation of products, and easy recovery of the catalyst.
The aim of the invention is achieved by the following technical scheme.
A method for synthesizing pinacol by selective electroreduction coupling of active hydrogen-mediated carbonyl compounds in water comprises the steps of reacting a three-electrode system with Carbon Paper (CP) as a working electrode, and carrying out electrochemical selective reduction on carbonyl compounds serving as reaction substrates by constant potential to obtain corresponding pinacol compounds, wherein the reaction potential is-1.6-1.1V (vs. RHE); in addition, the amplification experiment of synthesizing pinacol by the carbonyl compound through the electro-reduction coupling is carried out in the electro-catalytic membrane reactor, so that the method has higher conversion rate and selectivity; meanwhile, the high conversion rate and the selective synthesis of the pinacol can be realized by taking the low-cost monoalcohol as a raw material through electrochemical anodic oxidation-cathodic reduction relay catalysis.
The preparation reaction is as follows:
the carbonyl compound of the reaction substrate is benzaldehyde, 4-methyl-benzaldehyde, 2-methyl-benzaldehyde, 3, 4-dimethyl-benzaldehyde, 4-methoxy-benzaldehyde, 4-trifluoromethyl-benzaldehyde, 4-fluoro-benzaldehyde, 2-chloro-benzaldehyde, acetophenone, 3-methylacetophenone, 4-methoxyacetophenone and 4-fluoro acetophenone.
The corresponding pinacols are 1, 2-diphenylethane-1, 2-diol, 1, 2-di-p-methylphenylethane-1, 2-diol, 1, 2-dimethylbenzene-1, 2-diol, 1, 2-bis (3, 4-dimethylphenyl) ethane-1, 2-diol, 1, 2-bis (4-methoxyphenyl) ethane-1, 2-diol, 1, 2-bis (4-trifluoromethylphenyl) ethane-1, 2-diol, 1, 2-bis (4-fluorophenyl) ethane-1, 2-diol, 1, 2-bis (3-chlorophenyl) ethane-1, 2-diol, 2, 3-dimethylbenzene butane-2, 3-diol, 2, 3-bis (4-methoxyphenyl) butane-2, 3-diol, 2, 3-bis (4-fluorophenyl) butane-2, 3-diol.
When constant potential electrochemical selective reduction is carried out, the atmosphere is air, and the reaction environment temperature is 20-25 ℃ at room temperature; the platinum sheet is the counter electrode and the Hg/HgO (1.0M KOH) electrode is the reference electrode.
When the potentiostatic electrochemical selective reduction is carried out, an H-type electrolytic cell is used as a container, an ion exchange membrane is used for separating a cathode chamber from an anode chamber, alkali liquor is respectively added into the cathode chamber and the anode chamber, and carbonyl compounds serving as reaction substrates are added into a cathode part and uniformly dispersed.
The alkaline solution is potassium hydroxide or sodium hydroxide aqueous solution, preferably 25mL of 1.0M KOH aqueous solution.
In the potentiostatic electrochemical selective reduction, the reaction is completely converted for 8-15h, preferably 10h; after the reaction is completed, extraction is performed by using an organic reagent (such as ethyl acetate and methylene dichloride), and reduced pressure distillation is performed.
After the carbonyl compound as the reaction substrate is completely reacted, removing the reaction solution in the electrolytic cell and carrying out corresponding treatment on the electrolyte, after the electrolytic cell is cleaned, continuously adding the carbonyl compound as the reaction substrate to the cathode electrolytic cell in a summarizing way by using the catalyst electrode material, repeating the potentiostatic electrochemical selective reduction reaction for a plurality of times (such as 5-10 times), and displaying the same property to obtain the same target product, namely the corresponding pinacol compound, when the carbonyl compound as the reaction substrate is completely reacted, calculating the required electric quantity (1.0 mmol of the reaction substrate is completely reacted to consume 193C approximately) according to the consumption of the reaction substrate, or judging according to the reaction time, or judging according to the fact that the curve is reduced to a platform.
The application of carbon paper as a catalyst in the preparation of the corresponding pinacol compound by electrochemical selective reduction of a reaction substrate coupling carbonyl compound through constant potential.
The method for processing the Carbon Paper (CP) comprises the following steps:
step 1, soaking carbon paper (the size is 30mm multiplied by 10 mm) in acetone, performing ultrasonic cleaning for 15min to remove organic matters on the surface, and then soaking in water, performing ultrasonic cleaning for 15min to remove residual acetone on the carbon paper;
step 2, soaking the carbon paper obtained in the step 1 in a beaker containing acid liquor and sealing the beaker, and placing the beaker in an oil bath at 60 ℃ for constant temperature for 24 hours, wherein the acid liquor is formed by mixing water, concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1:1;
and 3, taking out the beaker, cooling to the room temperature of 20-25 ℃, recovering acid liquor, washing the carbon paper with water to be neutral, and soaking the carbon paper in water for standby.
The beneficial effects of the invention are as follows: in a wider potential range, the high-efficiency and high-selectivity synthesis of the pinacol compound can be realized, and the pinacol compound has higher functional group tolerance and better substrate applicability;
the invention uses cheap and easily available high-efficiency carbon materials as electrodes, takes green, safe and abundant water as solvent and hydrogen source, has mild reaction conditions, does not need heating, has simple and convenient operation, easily separated products and easily recovered catalyst, and effectively avoids the problems of noble metal catalyst in other synthesis methods, such as complex operation, long reaction time, low yield, poor selectivity, strong reagent toxicity, environmental pollution caused by reaction byproducts and the like;
the carbon electrode has good stability, can be recycled for multiple times, and the Faraday efficiency, yield and selectivity of the generated pinacol are not obviously changed;
in addition, the carbonyl compound is subjected to electroreduction coupling to synthesize pinacol, and the amplification experiment can be carried out in the electrocatalytic membrane reactor, so that the method has higher conversion rate and selectivity, and the application prospect of large-scale production of the method is reflected; meanwhile, the invention can also realize the synthesis of pinacol by taking cheap monoalcohol (such as benzyl alcohol as a reactant) through electrochemical anodic oxidation-cathodic reduction relay catalytic reaction, and embody the characteristic of economy of reaction atoms.
Drawings
Fig. 1 is a Scanning Electron Microscope (SEM) image of Carbon Paper (CP) as a working electrode;
FIG. 2 is a Raman spectrum image of carbon paper as a working electrode;
FIG. 3 is a substrate development schematic diagram of the synthesis of pinacol compounds by electroreduction coupling of carbonyl compounds using carbon paper as a working electrode;
FIG. 4 is a nuclear magnetic resonance spectrum of the product 1, 2-diphenylethane-1, 2-diol (2 a) obtained in example one, wherein the first web is 1 H NMR spectrum, second web is 13 C NMR spectrum;
FIG. 5 is a nuclear magnetic resonance spectrum of the product 1, 2-di-p-methylphenylethane-1, 2-diol (2 b) obtained in example two, wherein the first web is 1 H NMR spectrum, second web is 13 C NMR spectrum;
FIG. 6 is a nuclear magnetic resonance spectrum of the product 1, 2-di-o-tolyl-1, 2-diol (2 c) prepared in example III, wherein the first web is 1 H NMR spectrum, second web is 13 C NMR spectrum;
FIG. 7 is a nuclear magnetic resonance spectrum of the product 1, 2-bis (3, 4-dimethylphenyl) ethane-1, 2-diol (2 d) prepared in example four, wherein the first web is 1 H NMR spectrum, second web is 13 C NMR spectrum;
FIG. 8 is a nuclear magnetic resonance spectrum of the product 1, 2-bis (4-methoxyphenyl) ethane-1, 2-diol (2 e) prepared in example five, wherein the first web is 1 H NMR spectrum, second web is 13 C NMR spectrum;
FIG. 9 is a nuclear magnetic resonance spectrum of the product 1, 2-bis (4-trifluoromethylphenyl) ethane-1, 2-diol (2 f) prepared in example six, wherein the first web is 1 H NMR spectrum, second web is 13 C NMR spectrum;
FIG. 10 is a nuclear magnetic resonance spectrum of the product 1, 2-bis (4-fluorophenyl) ethane-1, 2-diol (2 g) prepared in example seven, wherein the first web is 1 H NMR spectrum, second web is 13 C NMR spectrum;
FIG. 11 is a product 1, 2-bis (3-chlorophenyl) ethanol prepared according to example eightAn alkane-1, 2-diol (2 h) nuclear magnetic spectrum, wherein the first amplitude is 1 H NMR spectrum, second web is 13 C NMR spectrum;
FIG. 12 is a nuclear magnetic resonance spectrum of the product 2, 3-diphenylbutane-2, 3-diol (2 i) prepared in example nine, wherein the first amplitude is 1 H NMR spectrum, second web is 13 C NMR spectrum;
FIG. 13 is a nuclear magnetic resonance spectrum of 2, 3-dimethylbenzene butane-2, 3-diol (2 j) as the product obtained in example ten, in which the first web is 1 H NMR spectrum, second web is 13 C NMR spectrum;
FIG. 14 is a nuclear magnetic resonance spectrum of the product 2, 3-bis (4-methoxyphenyl) butane-2, 3-diol (2 k) prepared in example eleven, wherein the first web is 1 H NMR spectrum, second web is 13 C NMR spectrum;
FIG. 15 is a nuclear magnetic resonance spectrum of 2, 3-bis (4-fluorophenyl) butane-2, 3-diol (2 l) as a product obtained in example twelve, wherein the first web is 1 H NMR spectrum, second web is 13 C NMR spectrum;
other relevant drawings may be made by those of ordinary skill in the art from the above figures without undue burden.
Detailed Description
The technical scheme of the invention is further described by specific examples.
Embodiment one: synthesis of 1, 2-diphenylethane-1, 2-diol (2 a):
the H-type electrolytic cell is taken as a container, a cathode chamber and an anode chamber of the electrolytic cell are separated by an ion exchange membrane, 25mL of 1.0M KOH solution is respectively added, then 0.4mmol of benzaldehyde is added into the cathode chamber and is continuously stirred by a magneton, carbon paper is taken as a working electrode, a platinum sheet is taken as a counter electrode, and an Hg/HgO (1.0M KOH) electrode is taken as a reference electrode. Connected to an electrochemical workstation, a constant voltage of-1.3V vs. RHE was selected for i-t, when the electricity consumption was about 77C, indicating that 0.4mmol of benzaldehyde was theoretically completely reduced, the product was collected, extracted with ethyl acetate, distilled under reduced pressure, and then subjected to qualitative analysis by nuclear magnetism and mass spectrometry. The quantitative analysis is carried out by gas chromatography,the yield of 1, 2-diphenylethane-1, 2-diol (2 a) was about 99%. Product d 6 DMSO dissolution test hydrogen and carbon spectra as shown in figure 4.
Embodiment two: synthesis of 1, 2-Di-p-methylphenylethane-1, 2-diol (2 b):
the H-type electrolytic cell is taken as a container, a cathode chamber and an anode chamber of the electrolytic cell are separated by an ion exchange membrane, 25mL of 1.0M KOH solution is respectively added, then 0.4mmol of 4-methyl-benzaldehyde is added into the cathode chamber and is continuously stirred by a magneton, carbon paper is taken as a working electrode, a platinum sheet is taken as a counter electrode and a Hg/HgO (1.0M KOH) electrode is taken as a reference electrode. Connected to an electrochemical workstation, a constant voltage of-1.3V vs. RHE was selected for i-t, indicating that 0.4mmol of 4-methyl-benzaldehyde was theoretically completely reduced when the electricity was approximately consumed at 77C. The product was collected, extracted with ethyl acetate, distilled under reduced pressure, and analyzed qualitatively by nuclear magnetism and mass spectrometry. The yield of 1, 2-di-p-methylphenylethane-1, 2-diol (2 b) was approximately 98% by gas chromatography. Product d 6 DMSO dissolution test hydrogen profile and carbon profile as shown in figure 5.
Embodiment III: synthesis of 1, 2-Di-o-tolyl-1, 2-diol (2 c):
the H-type electrolytic cell is taken as a container, a cathode chamber and an anode chamber of the electrolytic cell are separated by an ion exchange membrane, 25mL of 1.0M KOH solution is respectively added, then 0.4mmol of 2-methyl-benzaldehyde is added into the cathode chamber and is continuously stirred by a magneton, carbon paper is taken as a working electrode, a platinum sheet is taken as a counter electrode and a Hg/HgO (1.0M KOH) electrode is taken as a reference electrode. Connected to an electrochemical workstation, a constant voltage of-1.3V vs. RHE was selected for i-t, indicating that 0.4mmol of 2-methyl-benzaldehyde was theoretically completely reduced when the electricity was approximately consumed at 77C. The product was collected, extracted with ethyl acetate, distilled under reduced pressure, and analyzed qualitatively by nuclear magnetism and mass spectrometry. The yield of 1, 2-di-o-tolyl-1, 2-diol (2 c) was quantitatively analyzed by gas chromatography and found to be about 98%. Product d 6 DMSO dissolution test hydrogen and carbon spectra as shown in figure 6.
Embodiment four: synthesis of 1, 2-bis (3, 4-dimethylphenyl) ethane-1, 2-diol (2 d):
h-type electrolytic cell as container, cathode chamber and electrolytic cellThe anode chamber was separated by an ion exchange membrane and 25mL of 1.0M KOH solution was added, respectively, then 0.4mmol of 3, 4-dimethyl-benzaldehyde was added to the cathode chamber and stirred continuously with magnetons, with carbon paper as the working electrode, platinum sheet as the counter electrode and Hg/HgO (1.0M KOH) electrode as the reference electrode. Connected to an electrochemical workstation, a constant voltage of-1.3V vs. RHE was selected for i-t, indicating that 0.4mmol of 3, 4-dimethyl-benzaldehyde was theoretically completely reduced when the electricity was approximately consumed at 77C. The product was collected, extracted with ethyl acetate, distilled under reduced pressure, and analyzed qualitatively by nuclear magnetism and mass spectrometry. The yield of 1, 2-bis (3, 4-dimethylphenyl) ethane-1, 2-diol (2 d) was about 97% by gas chromatography. Product d 6 DMSO dissolution test hydrogen and carbon spectra as shown in figure 7.
Fifth embodiment: synthesis of 1, 2-bis (4-methoxyphenyl) ethane-1, 2-diol (2 e):
the H-type electrolytic cell is taken as a container, a cathode chamber and an anode chamber of the electrolytic cell are separated by an ion exchange membrane, 25mL of 1.0M KOH solution is respectively added, then 0.4mmol of 4-methoxy-benzaldehyde is added into the cathode chamber and is continuously stirred by a magneton, carbon paper is taken as a working electrode, a platinum sheet is taken as a counter electrode and a Hg/HgO (1.0M KOH) electrode is taken as a reference electrode. Connected to an electrochemical workstation, a constant voltage of-1.3V vs. RHE was chosen for i-t, indicating that 0.4mmol of 4-methoxy-benzaldehyde was theoretically completely reduced when the electricity was approximately consumed at 77C. The product was collected, extracted with ethyl acetate, distilled under reduced pressure, and analyzed qualitatively by nuclear magnetism and mass spectrometry. The yield of 1, 2-bis (4-methoxyphenyl) ethane-1, 2-diol (2 e) was about 90% by quantitative analysis by gas chromatography. Product d 6 DMSO dissolution test hydrogen and carbon spectra as shown in figure 8.
Example six: synthesis of 1, 2-bis (4-trifluoromethylphenyl) ethane-1, 2-diol (2 f):
the H-type electrolytic cell is taken as a container, a cathode chamber and an anode chamber of the electrolytic cell are separated by an ion exchange membrane, 25mL of 1.0M KOH solution is respectively added, then 0.4mmol of 4-trifluoromethyl-benzaldehyde is added into the cathode chamber and is continuously stirred by a magneton, carbon paper is taken as a working electrode, a platinum sheet is taken as a counter electrode and Hg/HgO (1.0M KOH) electrode is taken as a reference electrode. Connected to an electrochemical workstation, a constant voltage of-1.3V vs. RHE was selected for i-t, indicating that 0.4mmol of 4-trifluoromethyl-benzaldehyde was theoretically completely reduced when the electricity was approximately consumed at 77C. The product was collected, extracted with ethyl acetate, distilled under reduced pressure, and analyzed qualitatively by nuclear magnetism and mass spectrometry. The yield of 1, 2-bis (4-trifluoromethylphenyl) ethane-1, 2-diol (2 f) was about 84% by gas chromatography. Product d 6 DMSO dissolution test hydrogen and carbon spectra as shown in figure 9.
Embodiment seven: synthesis of 1, 2-bis (4-fluorophenyl) ethane-1, 2-diol (2 g):
the H-type electrolytic cell is taken as a container, a cathode chamber and an anode chamber of the electrolytic cell are separated by an ion exchange membrane, 25mL of 1.0M KOH solution is respectively added, then 0.4mmol of 4-fluoro-benzaldehyde is added into the cathode chamber and is continuously stirred by a magneton, carbon paper is taken as a working electrode, a platinum sheet is taken as a counter electrode and an Hg/HgO (1.0M KOH) electrode is taken as a reference electrode. Connected to an electrochemical workstation, a constant voltage of-1.3V vs. RHE was selected for i-t, indicating that 0.4mmol of 4-fluoro-benzaldehyde was theoretically completely reduced when the electricity was approximately consumed at 77C. The product was collected, extracted with ethyl acetate, distilled under reduced pressure, and analyzed qualitatively by nuclear magnetism and mass spectrometry. The yield of 1, 2-bis (4-fluorophenyl) ethane-1, 2-diol (2 g) was about 98% by gas chromatography. Product d 6 DMSO dissolution test hydrogen and carbon spectra as shown in figure 10.
Example eight: synthesis of 1, 2-bis (3-chlorophenyl) ethane-1, 2-diol (2 h):
the H-type electrolytic cell is taken as a container, a cathode chamber and an anode chamber of the electrolytic cell are separated by an ion exchange membrane, 25mL of 1.0M KOH solution is respectively added, then 0.4mmol of 3-chloro-benzaldehyde is added into the cathode chamber and is continuously stirred by a magneton, carbon paper is taken as a working electrode, a platinum sheet is taken as a counter electrode and an Hg/HgO (1.0M KOH) electrode is taken as a reference electrode. Connected to an electrochemical workstation, a constant voltage of-1.3V vs. RHE was selected for i-t, indicating that 0.4mmol of 2-chloro-benzaldehyde was theoretically completely reduced when the electricity was approximately consumed at 77C. The product was collected, extracted with ethyl acetate, distilled under reduced pressure, and analyzed qualitatively by nuclear magnetism and mass spectrometry. Gas chromatographyQuantitative analysis was performed with a yield of 1, 2-bis (3-chlorophenyl) ethane-1, 2-diol (2 h) of about 82%. Product d 6 DMSO dissolution test hydrogen and carbon spectra as shown in figure 11.
Example nine: synthesis of 2, 3-diphenylbutane-2, 3-diol (2 i):
the H-type electrolytic cell is taken as a container, a cathode chamber and an anode chamber of the electrolytic cell are separated by an ion exchange membrane, 25mL of 1.0M KOH solution is respectively added, then 0.4mmol of 4-phenyl-benzaldehyde is added into the cathode chamber and is continuously stirred by a magneton, carbon paper is taken as a working electrode, a platinum sheet is taken as a counter electrode and a Hg/HgO (1.0M KOH) electrode is taken as a reference electrode. Connected to an electrochemical workstation, a constant voltage of-1.3V vs. RHE was chosen for i-t, indicating that 0.4mmol of acetophenone had theoretically been completely reduced when the electricity was approximately consumed at 77C. The product was collected, extracted with ethyl acetate, distilled under reduced pressure, and analyzed by qualitative analysis using nuclear magnetism and mass spectrometry. The yield of 2, 3-diphenylbutane-2, 3-diol (2 i) was about 99% by gas chromatography. Product d 6 DMSO dissolution test hydrogen and carbon spectra as shown in figure 12.
Example ten: synthesis of 2, 3-Dim-tolyltutane-2, 3-diol (2 j):
the H-type electrolytic cell is taken as a container, a cathode chamber and an anode chamber of the electrolytic cell are separated by an ion exchange membrane, 25mL of 1.0M KOH solution is respectively added, then 0.4mmol of 4-phenyl-benzaldehyde is added into the cathode chamber and is continuously stirred by a magneton, carbon paper is taken as a working electrode, a platinum sheet is taken as a counter electrode and a Hg/HgO (1.0M KOH) electrode is taken as a reference electrode. Connected to an electrochemical workstation, a constant voltage of-1.3V vs. RHE was chosen for i-t, indicating that 0.4mmol of 3-methylacetophenone had theoretically been completely reduced when the electrical power was approximately consumed at 77C. The product was collected, extracted with ethyl acetate, distilled under reduced pressure, and analyzed by qualitative analysis using nuclear magnetism and mass spectrometry. The yield of 2, 3-dimethylbenzene butane-2, 3-diol (2 j) was about 95% by gas chromatography. Product d 6 DMSO dissolution test hydrogen and carbon spectra as shown in figure 13.
Example eleven: synthesis of 2, 3-bis (4-methoxyphenyl) butane-2, 3-diol (2 k):
by H-electrolysisThe cell was a vessel, the cathode and anode compartments of the cell were separated by an ion exchange membrane and 25mL of 1.0M KOH solution was added, respectively, then 0.4mmol of 4-phenyl-benzaldehyde was added to the cathode compartment and stirred continuously with magnetons, with carbon paper as the working electrode, platinum sheet as the counter electrode and Hg/HgO (1.0M KOH) electrode as the reference electrode. Connected to an electrochemical workstation, a constant voltage of-1.3V vs. RHE was chosen for i-t, indicating that 0.4mmol of 4-methoxyacetophenone had theoretically been completely reduced when the electricity was approximately consumed at 77C. The product was collected, extracted with ethyl acetate, distilled under reduced pressure, and analyzed by qualitative analysis using nuclear magnetism and mass spectrometry. The yield of 2, 3-bis (4-methoxyphenyl) butane-2, 3-diol (2 k) was about 97% by quantitative analysis by gas chromatography. Product d 6 DMSO dissolution test hydrogen and carbon spectra as shown in figure 14.
Embodiment twelve: synthesis of 2, 3-bis (4-fluorophenyl) butane-2, 3-diol (2 l):
the H-type electrolytic cell is taken as a container, a cathode chamber and an anode chamber of the electrolytic cell are separated by an ion exchange membrane, 25mL of 1.0M KOH solution is respectively added, then 0.4mmol of 4-phenyl-benzaldehyde is added into the cathode chamber and is continuously stirred by a magneton, carbon paper is taken as a working electrode, a platinum sheet is taken as a counter electrode and a Hg/HgO (1.0M KOH) electrode is taken as a reference electrode. Connected to an electrochemical workstation, a constant voltage of-1.3V vs. RHE was chosen for i-t, indicating that 0.4mmol of 4-fluoro acetophenone was theoretically completely reduced when the electricity was approximately consumed at 77C. The product was collected, extracted with ethyl acetate, distilled under reduced pressure, and analyzed by qualitative analysis using nuclear magnetism and mass spectrometry. The yield of 2, 3-bis (4-fluorophenyl) butane-2, 3-diol (2 l) was about 99% by gas chromatography. Product d 6 DMSO dissolution test hydrogen and carbon spectra as shown in figure 15.
The foregoing detailed description of the invention has been presented for purposes of illustration and description, but is not intended to limit the scope of the invention. All equivalent changes and modifications within the scope of the present invention are intended to be covered by the present invention.
Claims (8)
1. A method for synthesizing pinacol by active hydrogen-mediated selective electroreductive coupling of carbonyl compounds in water, which is characterized by comprising the following steps: in an aqueous medium, a standard three-electrode system, namely a working electrode, a reference electrode and a counter electrode, which takes carbon paper as a working electrode is reacted, a carbonyl compound as a reaction substrate is subjected to electrochemical selective reduction at a constant potential to obtain a corresponding pinacol compound, wherein the reaction potential is-1.6 to-1.1V, and an Hg/HgO (1.0M KOH) electrode is taken as the reference electrode;
the carbonyl compound of the reaction substrate is benzaldehyde, 4-methyl-benzaldehyde, 2-methyl-benzaldehyde, 3, 4-dimethyl-benzaldehyde, 4-methoxy-benzaldehyde, 4-trifluoromethyl-benzaldehyde, 4-fluoro-benzaldehyde, 2-chloro-benzaldehyde, acetophenone, 3-methylacetophenone, 4-methoxyacetophenone and 4-fluoro acetophenone; the corresponding pinacols are 1, 2-diphenylethane-1, 2-diol, 1, 2-di-p-methylphenylethane-1, 2-diol, 1, 2-dimethylbenzene-1, 2-diol, 1, 2-bis (3, 4-dimethylphenyl) ethane-1, 2-diol, 1, 2-bis (4-methoxyphenyl) ethane-1, 2-diol, 1, 2-bis (4-trifluoromethylphenyl) ethane-1, 2-diol, 1, 2-bis (4-fluorophenyl) ethane-1, 2-diol, 1, 2-bis (3-chlorophenyl) ethane-1, 2-diol, 2, 3-dimethylbenzene butane-2, 3-diol, 2, 3-bis (4-methoxyphenyl) butane-2, 3-diol, 2, 3-bis (4-fluorophenyl) butane-2, 3-diol;
when the potentiostatic electrochemical selective reduction is carried out, an H-type electrolytic cell is used as a container, an ion exchange membrane is used for separating a cathode chamber from an anode chamber, alkali liquor is respectively added into the cathode chamber and the anode chamber, and carbonyl compounds which are reaction substrates are added into a cathode part and uniformly dispersed, wherein the alkali liquor adopts potassium hydroxide or sodium hydroxide aqueous solution.
2. The method for synthesizing pinacol by active hydrogen-mediated selective electroreductive coupling of carbonyl compounds in water according to claim 1, wherein the method comprises the steps of: when constant potential electrochemical selective reduction is carried out, the atmosphere is air, and the reaction environment temperature is 20-25 ℃ at room temperature; the platinum sheet is a counter electrode.
3. The method for synthesizing pinacol by active hydrogen-mediated selective electroreductive coupling of carbonyl compounds in water according to claim 1, wherein the method comprises the steps of: the lye was 25mL of 1.0M aqueous KOH.
4. The method for synthesizing pinacol by active hydrogen-mediated selective electroreductive coupling of carbonyl compounds in water according to claim 1, wherein the method comprises the steps of: in the potentiostatic electrochemical selective reduction, the reaction time is 8-15h.
5. The method for synthesizing pinacol by active hydrogen mediated selective electroreductive coupling of carbonyl compounds in water according to claim 4, wherein the method comprises the steps of: in the potentiostatic electrochemical selective reduction, the reaction was completed for 10 hours.
6. The method for synthesizing pinacol by active hydrogen-mediated selective electroreductive coupling of carbonyl compounds in water according to claim 1, wherein the method comprises the steps of: after the completion of the reaction, extraction was performed using ethyl acetate or methylene chloride as an organic reagent, and distillation was performed under reduced pressure.
7. The method for synthesizing pinacol by active hydrogen-mediated selective electroreductive coupling of carbonyl compounds in water according to claim 1, wherein the method comprises the steps of: after the carbonyl compound of the reaction substrate is completely reacted, removing the reaction liquid in the electrolytic cell, correspondingly treating the electrolyte, cleaning the electrolytic cell, continuously adding the carbonyl compound of the reaction substrate into the cathode electrolytic cell by using the catalyst electrode material, repeating the potentiostatic electrochemical selective reduction reaction for 5-10 times, and displaying the same property to obtain the same target product, namely the corresponding pinacol compound, when the carbonyl compound of the reaction substrate is completely reacted, calculating the required electric quantity according to the consumption of the reaction substrate, judging according to the reaction time by using 1.0mmol of the reaction substrate, or judging according to the complete reaction consumption 193C of the reaction substrate, or judging according to the curve occurrence falling to a platform.
8. The method for synthesizing pinacol by active hydrogen-mediated selective electroreductive coupling of carbonyl compounds in water according to claim 1, wherein the method comprises the steps of: the carbon paper is treated according to the following steps:
step 1, soaking carbon paper in acetone, performing ultrasonic cleaning for 15min to remove organic matters on the surface, and then soaking in water, performing ultrasonic cleaning for 15min to remove residual acetone on the carbon paper;
step 2, soaking the carbon paper obtained in the step 1 in a beaker containing acid liquor and sealing the beaker, and placing the beaker in an oil bath at 60 ℃ for constant temperature for 24 hours, wherein the acid liquor is formed by mixing water, concentrated sulfuric acid and concentrated nitric acid in a volume ratio of 1:1:1;
and 3, taking out the beaker, cooling to the room temperature of 20-25 ℃, recovering acid liquor, washing the carbon paper with water to be neutral, and soaking the carbon paper in water for standby.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010886293.3A CN114108014B (en) | 2020-08-28 | 2020-08-28 | Method for synthesizing pinacol by selective electroreduction coupling of active hydrogen-mediated carbonyl compound in water |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010886293.3A CN114108014B (en) | 2020-08-28 | 2020-08-28 | Method for synthesizing pinacol by selective electroreduction coupling of active hydrogen-mediated carbonyl compound in water |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114108014A CN114108014A (en) | 2022-03-01 |
| CN114108014B true CN114108014B (en) | 2023-08-11 |
Family
ID=80375093
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202010886293.3A Active CN114108014B (en) | 2020-08-28 | 2020-08-28 | Method for synthesizing pinacol by selective electroreduction coupling of active hydrogen-mediated carbonyl compound in water |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114108014B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115125553B (en) * | 2022-04-26 | 2023-12-22 | 绍兴久孚新材料科技有限公司 | Electrochemical synthesis method of alcohol |
| CN115369432B (en) * | 2022-08-23 | 2024-08-20 | 大连理工大学 | Method for preparing nitrile by electrocatalytic coupling of primary alcohol and ammonia substance |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3899401A (en) * | 1973-08-25 | 1975-08-12 | Basf Ag | Electrochemical production of pinacols |
| US3984294A (en) * | 1974-08-28 | 1976-10-05 | Basf Aktiengesellschaft | Electrochemical manufacture of pinacol |
| US3992269A (en) * | 1975-11-03 | 1976-11-16 | Diamond Shamrock Corporation | Production of pinacols in a membrane cell |
-
2020
- 2020-08-28 CN CN202010886293.3A patent/CN114108014B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3899401A (en) * | 1973-08-25 | 1975-08-12 | Basf Ag | Electrochemical production of pinacols |
| US3984294A (en) * | 1974-08-28 | 1976-10-05 | Basf Aktiengesellschaft | Electrochemical manufacture of pinacol |
| US3992269A (en) * | 1975-11-03 | 1976-11-16 | Diamond Shamrock Corporation | Production of pinacols in a membrane cell |
Non-Patent Citations (1)
| Title |
|---|
| Reversible dimerization of anion radicals of carbonyl compounds and the electrosynthesis of pinacols. the case of 9-fluorenone;Andrey s. mendkovich et. al.;《Electrochimica acta》;第358卷;136903 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114108014A (en) | 2022-03-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN114108014B (en) | Method for synthesizing pinacol by selective electroreduction coupling of active hydrogen-mediated carbonyl compound in water | |
| CN101792913B (en) | Paired electrolytic synthesis method for producing butanedioic acid and sulfuric acid | |
| Wu et al. | Strengthening the Synergy between Oxygen Vacancies in Electrocatalysts for Efficient Glycerol Electrooxidation | |
| EP4343033A1 (en) | Method for preparing glycolate by electrocatalysis of ethylene glycol or electrocatalytic reforming of waste plastic pet | |
| CN113136593A (en) | Method for synthesizing ibuprofen | |
| CN110016684B (en) | Method for preparing enamine by electrolyzing amino acid | |
| CN110016689B (en) | Electrochemical preparation method of allyl alcohol | |
| CN118086929A (en) | Method for electrochemically synthesizing salicylaldehyde | |
| CN114606514A (en) | Preparation method of alkaline electrolysis hydrogen production electrode | |
| CN113073347B (en) | Method for electrochemically synthesizing syringaldehyde by taking water as oxygen source | |
| CN116425996B (en) | Metal organic framework material and ligand thereof and application of metal organic framework material in photocatalytic hydrogen production | |
| JP2004250544A (en) | Method for recovering terephthalic acid from poly(terephthalic acid ester) | |
| CN113789529B (en) | Synthesis method for photoelectrocatalytic oxidation of glyoxal into glyoxylic acid | |
| CN109913890B (en) | Method for electrochemically preparing tridecane from azelaic acid | |
| CN110016685B (en) | Method for preparing conjugated diene by electrolyzing monoene diacid | |
| CN117845240A (en) | Dehydration esterification reaction | |
| CN118834233A (en) | 4- (Hydroxy dimethyl silicon base) oxy salicylic acid compound, synthesis method and application thereof in metal battery and hydrogen production | |
| CN116283559A (en) | Purification and recovery method of PET electrocatalytic reforming anode product-glycollic acid | |
| CN117448880A (en) | Electrocatalyst, preparation method thereof and application of electrocatalyst in preparation of glycolate through electrocatalytic ethylene glycol | |
| Hu et al. | Rapid plasma preparation of CuO nanowires for efficient ammonia synthesis | |
| CN114774950A (en) | Electrochemical synthesis method of 2-methylthiobenzothiazole | |
| Pletsch et al. | Ex situ electro-organic synthesis–A method for unrestricted reaction control and new options for paired electrolysis | |
| CN116354460A (en) | Electrochemical process and device for generating electricity and producing fuel through sewage treatment in cooperation | |
| CN117107257A (en) | Low-energy-consumption catalysis method for oxidation upgrading of electrosynthesis hydrogen peroxide coupled PET (polyethylene terephthalate) plastic | |
| CN116536681A (en) | Environment-friendly hydrogen production process by coupling succinic acid prepared by electrochemical oxidation of waste PBT plastic |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |