CN101979713A - Method for electrolytic synthesis of parahydroxybenzaldehyde - Google Patents
Method for electrolytic synthesis of parahydroxybenzaldehyde Download PDFInfo
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- CN101979713A CN101979713A CN201010553948.1A CN201010553948A CN101979713A CN 101979713 A CN101979713 A CN 101979713A CN 201010553948 A CN201010553948 A CN 201010553948A CN 101979713 A CN101979713 A CN 101979713A
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Abstract
The invention discloses a method for synthesizing parahydroxybenzaldehyde by the electrolytic oxidation of sodium p-hydroxymandalate. The method is characterized by comprising the following steps of: performing electrolytic oxidation in a plate frame diaphragm electrolytic cell by controlling the temperature of the anode liquid to be 60 to 70 DEG C and the current density of the anode to be 500 to 2,000A/m<2>, wherein a nickel plate is used as a cathode, a titanium-matrix lead dioxide electrode is used as an anode, a cation-exchange membrane is used as diaphragm, 0.5 to 3.0 mol/L aqueous alkali of sodium hydroxide is used as cathode liquid, the mixed solution of the aqueous alkali, 0.2 to 2.0mol/L sodium p-hydroxymandalate and 0.01 to 0.1mol/L iodate is used as anode liquid; and acidizing electrolytic liquid, decarboxylating the acidized product, cooling and crystallizing and separating to obtain the parahydroxybenzaldehyde, wherein the yield is 96.2 percent and the anode current efficiency is 93.7 percent. The method has high oxidation yield and high current efficiency and is environmentally-friendly and suitable for mass production.
Description
Technical field
The present invention relates to a kind of electrolyzing synthesizing method of p-Hydroxybenzaldehyde, particularly is the method for the synthetic p-Hydroxybenzaldehyde of medium electrolytic oxidation parahydroxymandelic acid sodium with the periodate, belongs to field of medicine and chemical technology.
Background technology
P-Hydroxybenzaldehyde (4-Hydroxybenzaldehyde), molecular formula C
7H
6O, molecular weight 122, light yellow or off-white color xln, fusing point 115-118 ℃, easily distillation is soluble in ethanol, ether, acetone, ethyl acetate in air, and is water-soluble slightly, is dissolved in benzene, and aromatic odour is arranged.P-Hydroxybenzaldehyde is the important intermediate of synthetic medicine, spices and liquid crystal material, is the fine chemical product that raw material can be produced a series of high added values with the p-Hydroxybenzaldehyde.
The p-Hydroxybenzaldehyde synthetic method is a lot, and " Anhui chemical industry " 2008, the 3rd phase, the 17-19 page or leaf is described in detail various synthetic methods, at present industrial main employing p-cresol catalytic oxidation and p-cresol chlorinolysis.Oxoethanoic acid and methyl catechol condensation-oxidation is produced vanillin food grade,1000.000000ine mesh and has been realized heavy industrialization, the contriver is once " chemical science and technology " 1999, the 4th volume, the 42-44 page or leaf is reported the operational path for preparing vanillin food grade,1000.000000ine mesh with cuprous oxide catalysis oxidation 3 methoxy 4 hydroxymandelic acid, and a day disclosure special permission communique JP52027739 (1977-0-02) has disclosed the electrolytic oxidation 3 methoxy 4 hydroxymandelic acid and prepared the vanillin food grade,1000.000000ine mesh method.Be subjected to the acetaldehyde acid system to produce the influence of vanillin food grade,1000.000000ine mesh technology, the synthetic p-Hydroxybenzaldehyde of numerous and confused both at home and abroad research parahydroxymandelic acid oxidation is to realize that with oxoethanoic acid and phenol be the synthetic p-Hydroxybenzaldehyde of raw material." J.Chem.Tech.Biotechnol. " 1986, the 36th volume, the 38-46 page or leaf report operational path of the synthetic p-Hydroxybenzaldehyde of copper hydroxide oxidation parahydroxymandelic acid sodium, there is the cupric oxide difficult separation and recycling in oxidising process yield 78% and consumes high problem.Spain patent ES2116886 (1998-07-16) has disclosed the method for the synthetic p-Hydroxybenzaldehyde of a kind of electrolytic oxidation parahydroxymandelic acid sodium." Journal of Applied Electrochemistry " 1999, the 29th volume, the play-by-play of 265-270 page or leaf by the method for parahydroxymandelic acid sodium electrolytic synthesis p-Hydroxybenzaldehyde, the anode and the negative electrode that adopt are charcoal felt electrode, barrier film is the Nafionl17 cationic exchange membrane, and the parahydroxymandelic acid na concn is 0.6mol/L in the 2.7mol/L NaOH anolyte, and catholyte is 2.7mol/L NaOH, electrolyte temperature 30-60 ℃, current density 1000A/m
2Under these conditions, p-Hydroxybenzaldehyde productive rate 90%, but exist charcoal felt electrode easily to lose activity in the expanding test for Organic pollutants, productive rate only 78.3% when adopting industrial titanium matrix lead dioxide electrode commonly used to carry out the oxidation of parahydroxymandelic acid sodium, has the high and yield problem of unstable of power consumption.
Along with the range of application of p-Hydroxybenzaldehyde constantly enlarges, the domestic and international market demand rises year by year in recent years, and raw material parahydroxymandelic acid production cost need be adopted an effective measure and improve the oxidising process yield to improve productivity effect than higher.Existing method exists production cost height and environmental pollution problems, and the throughput of p-Hydroxybenzaldehyde far can not be met the need of market, and research p-Hydroxybenzaldehyde new synthetic method has very important realistic meaning.
Summary of the invention
The purpose of this invention is to provide a kind of is the method for the synthetic p-Hydroxybenzaldehyde of medium electrolytic oxidation parahydroxymandelic acid sodium with the periodate, solves prior art and produce the problem that yield is low, power consumption is high and production cost is high when industrial application.
The contriver is carrying out on the organic electrolysis study on the synthesis basis for a long time, find that parahydroxymandelic acid sodium can generate p-Hydroxybenzaldehyde in the anode surface oxidation in alkaline electrolyte, but because the parahydroxymandelic acid molecular ratio is bigger, molecular migration and velocity of diffusion are slow, and concentration polarization causes bath voltage to raise and electrolytic efficiency descends.
Discover that adding iodate in the alkalitropism electrolytic solution carries out electrolysis as medium, periodate and the reaction of parahydroxymandelic acid sodium generate p-Hydroxybenzaldehyde sodium phenolate and iodate, iodate is a periodate at the anode surface oxidation regeneration, thereby parahydroxymandelic acid sodium oxidation reaction zone is transferred to the anolyte from anode surface, overcome the mass transfer difficulty of organic molecule.The synthetic p-Hydroxybenzaldehyde reaction process of electrolytic oxidation parahydroxymandelic acid sodium can be expressed as in alkaline electrolyte:
Theoretical research result is applied in the practice of innovation of electrolytic synthesis p-Hydroxybenzaldehyde, and the technical scheme of taking is:
Raw material parahydroxymandelic acid sodium is synthetic by oxoethanoic acid, phenol and the sodium hydroxide reference literature reaction conditions chamber of experimentizing, after finishing, reaction uses the unreacted phenol of toluene extracting and separating, the water of raffinate is through vacuum concentration, cooling, crystallization, separation, washing, drying, obtain a water parahydroxymandelic acid sodium white powder, also drying not, analyzing directly feeds intake behind the content carries out reduction reaction.
Parahydroxymandelic acid sodium electrolytic acid cleaning oxydation process carries out in the plate and frame diaphragm sell, and negative electrode is the nickel plate, can be stainless steel, titanium or graphite cake also, requires cathode material to have chemical stability in basic solution; Anode is a titanium matrix lead dioxide electrode, can be lead or lead alloy plate also, requires anode material to have higher oxygen evolution potential; Barrier film is perfluorinated sulfonic acid type or perfluorocarboxylic acid type cationic exchange membrane, and preferred Nafion324 cationic exchange membrane requires film that ion-selective permeability is wanted high, and resistance is little, has certain mechanical strength.Electric tank cathode chamber and anolyte compartment's thickness are controlled at 2-3mm with the lattice plate, to reduce bath voltage.Add 0.5-3.0mol/L sodium hydroxide or potassium hydroxide solution respectively in catholyte storage tank and anolyte storage tank, bath voltage was low when alkali concn was big, oxidation productive rate height, but sepn process consumption acids amount is bigger.With two magnetic drive pumps electrolytic solution is squeezed into electric tank cathode chamber and anolyte compartment's circulation during enforcement, fed current activation 0.5 hour to electrolyzer with constant current power supply.
Add previously prepared parahydroxymandelic acid sodium raw materials and iodate in the anode liquid storage tank, parahydroxymandelic acid sodium starting point concentration 0.2-2.0mol/L in the anolyte, productive rate is higher under the low concentration, but throughput is low.The iodate that adds in the anolyte is sodium iodate, Potassium Iodate, sodium periodate or potassium periodate, adding iodate concentration is 0.01-0.1mol/L, current efficiency is higher during higher concentration, but the iodate consumption is big, and parahydroxymandelic acid sodium can directly carry out oxidizing reaction at electrode surface when iodate concentration was low.Start electrolyte circulating pump during enforcement, with 60-70 ℃ of heating in water bath control electrolyte temperature, give electrolyzer with electricity with constant current power supply, anodic current density is 500-2000A/m
2, improve anodic current density and cause that current efficiency descends.Timing sampling detects, and selects electrolysis time that raw material parahydroxymandelic acid sodium is almost completely transformed.After electrolytic oxidation is finished anolyte is changed in the separator tank, oxidation products mainly is dissolved in the anode alkaline solution with parahydroxyacet-ophenone acid na form, can select mineral acid acidifyings such as hydrochloric acid, sulfuric acid, phosphoric acid that its decarboxylation is generated p-Hydroxybenzaldehyde.For preventing in the decarboxylation procedure to form the chloro by product, preferably carry out acidifying with dilute sulphuric acid, adjust pH value of solution 1-3, be heated to 95 ℃ when not having gas to emit again decarboxylation complete.Vacuum concentration adopts the crystallisation by cooling method to separate the p-Hydroxybenzaldehyde product to 1/3rd of the solution original volume, preferably reaction solution is cooled to 5-10 ℃, and most of product crystallization is separated out.Adopt vacuum filtration or centrifugation to separate the crystallization of separating out, obtain p-Hydroxybenzaldehyde with cold water washing, drying.Because p-Hydroxybenzaldehyde dissolves in cold water, for improving separation yield, with the further vacuum concentration of mother liquor, cooling, crystallization, the recyclable again a part of p-Hydroxybenzaldehyde of drying, but iodate spent ion exchange resin absorption recycling use in the mother liquor.
The parahydroxymandelic acid assay adopts liquid phase chromatography among the present invention, selects Tianjin, island LC-10 high performance liquid chromatograph for use.Chromatographic column: the C18 post (4.6mm * 250mm); Moving phase: methyl alcohol: water: phosphoric acid=1: 3: 0.03 (volume ratio); Flow velocity: 1.0mL/min; Detect wavelength: 230nm; Column temperature: room temperature.The p-Hydroxybenzaldehyde assay adopts liquid phase chromatography, chromatographic column: and the C18 post (4.6mm * 250mm); Moving phase: methyl alcohol: water=4: 1 (volume ratio); Flow velocity: 1.0mL/min; Detect wavelength: 284nm; Column temperature: room temperature.
Advantage of the present invention and beneficial effect are embodied in: the reaction of the synthetic p-Hydroxybenzaldehyde of Periodic acid medium electrolytic oxidation is carried out at normal temperatures and pressures, oxidizing reaction yield height, and the current efficiency height, pollution-free, be fit to produce in enormous quantities.
Embodiment
The present invention realizes in the following ways, describes in detail below in conjunction with embodiment:
Embodiment 1
In the 1000mL four-hole boiling flask that mechanical stirrer, thermometer, two dropping funnels and reflux condensing tube are housed, add deionized water 500mL and 30% liquid caustic soda 53.3g (0.4mol), in two dropping funnels, add 40% glyoxylic acid solution 74.1g (0.4mol) and 30% liquid caustic soda 53.3g (0.4mol) respectively.Under agitation in reactor, add phenol 45.1g (0.48mol) in batches, added in about 15 minutes, obtain light red sodium phenylate solution.In reactor, drip glyoxylic acid solution and liquid caustic soda simultaneously, keep temperature of reaction, added in about 3 hours, continue stirring reaction and extremely almost do not have till the remaining oxoethanoic acid in 4 hours at 40-45 ℃.Reaction finish the back with 10% hydrochloric acid acidizing reaction liquid to pH4, make unreacted phenol dissociate out, divide three extractions with 200mL toluene, distill recovery toluene and phenol and recycle.With the water vacuum concentration of raffinate to the 360mL, cooling, crystallization, separation, saturated nacl aqueous solution washing, 110 ℃ of dryings, a water parahydroxymandelic acid sodium white powder 69.3g, liquid chromatography for measuring content 96.1%.
Embodiment 2
Make negative electrode with the nickel sheet, titanium matrix plumbic oxide is made anode, and the Nafion324 ion-exchange membrane is assembled a plate and frame diaphragm sell as barrier film.Electric tank cathode, anode and diaphragm area are 20cm
2, cathode compartment and anolyte compartment's thickness are 2mm, and catholyte and anolyte are stored in respectively in the glass storage tank of 2000mL, with two magnetic drive pumps electrolytic solution are squeezed into electric tank cathode chamber and anolyte compartment's circulation.In catholyte storage tank and anolyte storage tank, add 2mol/L sodium hydroxide solution 500mL respectively, start electrolyte circulating pump, fed the 0.4A electric current 0.5 hour to electrolyzer, make the electrode surface activation with constant current power supply.
The parahydroxymandelic acid sodium 43.2g (0.2mol) and the sodium iodate reagent 4.0g (0.02mol) that add embodiment 1 preparation in the anode liquid storage tank, be heated to 60 ℃ with water-bath, start electrolyte circulating pump, feed 1A electric current, corresponding anodic current density 500A/m to electrolyzer with constant current power supply
2Timing sampling detects, after transforming fully, parahydroxymandelic acid sodium stops, common electric 11 hours, electrolyte temperature 60-65 ℃, after electrolytic oxidation is finished anolyte is changed in the separator tank, adjust anolyte with 40% sulphuric acid soln and carry out decarboxylic reaction to pH1-2, be heated to 95 ℃ till do not have gas to emit again.Vacuum concentration is cooled to 5 ℃ to 200mL with frozen water, crystallization, and vacuum filtration, cold water washing, drying obtain p-Hydroxybenzaldehyde 23.8g, liquid chromatography for measuring content 98.6%, yield 96.2%, anodic current efficiency 93.7%.
Embodiment 3
Adopt embodiment 2 electrolyzers, the parahydroxymandelic acid sodium 43.2g (0.2mol) and the Potassium Iodate reagent 4.2g (0.02mol) that add embodiment 1 preparation in the anode liquid storage tank, be heated to 60 ℃ with water-bath, start electrolyte circulating pump, feed 2A electric current, corresponding anodic current density 1000A/m with constant current power supply to electrolyzer
2Timing sampling detects, after transforming fully, parahydroxymandelic acid sodium stops, common electric 6.0 hours, electrolyte temperature 60-65 ℃, after electrolytic oxidation is finished anolyte is changed in the separator tank, adjust anolyte with 40% sulphuric acid soln and carry out decarboxylic reaction to pH1-2, be heated to 95 ℃ till do not have gas to emit again.Vacuum concentration is cooled to 5 ℃ to 200mL with frozen water, crystallization, and vacuum filtration, cold water washing, drying obtain p-Hydroxybenzaldehyde 23.3g, liquid chromatography for measuring content 98.0%, yield 93.6%, anodic current efficiency 91.5%.
Embodiment 4
Adopt embodiment 2 electrolyzers, the parahydroxymandelic acid sodium 43.2g (0.2mol) and the Potassium Iodate reagent 4.2g (0.02mol) that add embodiment 1 preparation in the anode liquid storage tank, be heated to 60 ℃ with water-bath, start electrolyte circulating pump, feed 4A electric current, corresponding anodic current density 2000A/m with constant current power supply to electrolyzer
2Timing sampling detects, after transforming fully, parahydroxymandelic acid sodium stops, common electric 3.0 hours, electrolyte temperature 65-70 ℃, after electrolytic oxidation is finished anolyte is changed in the separator tank, adjust anolyte with 40% sulphuric acid soln and carry out decarboxylic reaction to pH1-2, be heated to 95 ℃ till do not have gas to emit again.Vacuum concentration is cooled to 5 ℃ to 200mL with frozen water, crystallization, and vacuum filtration, cold water washing, drying obtain p-Hydroxybenzaldehyde 22.8g, liquid chromatography for measuring content 98.2%, yield 91=8%, anodic current efficiency 81.9%.
Claims (6)
1. the method for the synthetic p-Hydroxybenzaldehyde of an electrolytic oxidation parahydroxymandelic acid sodium, it is characterized in that adopting the sheet frame diaphragm sell, make negative electrode with the nickel plate, titanium matrix lead dioxide electrode is made anode, cationic exchange membrane is made barrier film, alkaline solution is made catholyte, alkaline solution adds parahydroxymandelic acid sodium and adds iodate and make anolyte, carry out electrolytic oxidation under control anode temperature and anodic current density, electrolysis is finished liquid and is obtained the p-Hydroxybenzaldehyde product through acidifying, decarboxylation, cooling, crystallization, separation.
2. according to the described method of claim 1, it is characterized in that anolyte initially contains 0.5-3.0mol/L sodium hydroxide and 0.2-2.0mol/L parahydroxymandelic acid sodium.
3. according to the described method of claim 1, it is characterized in that the iodate that adds in the basic anolyte is sodium iodate, Potassium Iodate, sodium periodate or potassium periodate.
4. according to the described method of claim 1, it is characterized in that adding iodate concentration in the anolyte is 0.01-0.1mol/L.
5. according to the described method of claim 1, the preferred anodes liquid temp is 60-70 ℃ when it is characterized in that electrolysis.
6. according to the described method of claim 1, anodic current density is 500-2000A/m when it is characterized in that electrolysis
2
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102992973A (en) * | 2012-12-05 | 2013-03-27 | 嘉兴市安瑞材料科技有限公司 | Industrial method for synthesizing p-hydroxy benzaldehyde in jet flow manner |
| CN106029627A (en) * | 2013-12-18 | 2016-10-12 | 罗地亚经营管理公司 | Method for separating mandelic compounds in salified form and use of same for preparing aromatic aldehyde |
| CN110004458A (en) * | 2019-04-08 | 2019-07-12 | 天津大学 | Electrochemical preparation method of acrolein |
| CN110982806A (en) * | 2019-08-30 | 2020-04-10 | 浙江工业大学 | Protein aryl derivative and preparation method thereof |
| WO2021102613A1 (en) * | 2019-11-25 | 2021-06-03 | Rhodia Operations | Electrochemical method for preparing vanillin or its derivatives |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1167166A (en) * | 1996-05-30 | 1997-12-10 | 天津大学 | Application of cation exchange membrane in preparation of dialdehyde starch by indirect electric synthesizing method |
-
2010
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Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1167166A (en) * | 1996-05-30 | 1997-12-10 | 天津大学 | Application of cation exchange membrane in preparation of dialdehyde starch by indirect electric synthesizing method |
Non-Patent Citations (2)
| Title |
|---|
| 《JOURNAL OF APPLIED ELECTROCHEMISTRY》 19991231 J. A. GOMIS等 Electrosynthesis of p-hydroxybenzaldehydefrom sodium p-hydroxymandelate 265-270 1-6 第29卷, 2 * |
| 《广东化工》 20040831 韦星船等 香兰素合成研究 18-20 1-6 , 第8期 2 * |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102992973A (en) * | 2012-12-05 | 2013-03-27 | 嘉兴市安瑞材料科技有限公司 | Industrial method for synthesizing p-hydroxy benzaldehyde in jet flow manner |
| CN102992973B (en) * | 2012-12-05 | 2014-12-03 | 嘉兴市安瑞材料科技有限公司 | Industrial method for synthesizing p-hydroxy benzaldehyde in jet flow manner |
| CN106029627A (en) * | 2013-12-18 | 2016-10-12 | 罗地亚经营管理公司 | Method for separating mandelic compounds in salified form and use of same for preparing aromatic aldehyde |
| CN106029627B (en) * | 2013-12-18 | 2020-02-28 | 罗地亚经营管理公司 | Method for isolating mandelic compounds in salified form and use thereof for preparing aromatic aldehydes |
| CN110004458A (en) * | 2019-04-08 | 2019-07-12 | 天津大学 | Electrochemical preparation method of acrolein |
| CN110982806A (en) * | 2019-08-30 | 2020-04-10 | 浙江工业大学 | Protein aryl derivative and preparation method thereof |
| WO2021102613A1 (en) * | 2019-11-25 | 2021-06-03 | Rhodia Operations | Electrochemical method for preparing vanillin or its derivatives |
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Application publication date: 20110223 |