CN1247819C - Paired electrolysis procss of preparing glyoxalic acid - Google Patents
Paired electrolysis procss of preparing glyoxalic acid Download PDFInfo
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- CN1247819C CN1247819C CN 01105992 CN01105992A CN1247819C CN 1247819 C CN1247819 C CN 1247819C CN 01105992 CN01105992 CN 01105992 CN 01105992 A CN01105992 A CN 01105992A CN 1247819 C CN1247819 C CN 1247819C
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- oxoethanoic acid
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Abstract
The present invention provides an electrolysis technology of preparing glyoxalic acid. An electrolyzing slot with a fixed bed cathode and a fixed bed anode is utilized in the electrolysis process, and simultaneously, the method of changed current (density) is utilized according to the content of glyoxalic acid in an electrolyte fluid to carry out electrolysis in the electrolysis process. The thickness range of the fixed bed anode and the fixed bed cathode is from 4 millimeters to 50 millimeters respectively, and the optimum thickness range is from 10 millimeters to 30 millimeters. The highest average apparent current density can reach 4500 A/m <2>, and the optimal average apparent current density is from 1000 A/m <2> to 3000 A / m<2>. Thus, compared with a plate electrode reactor, the production capacity of the electrolyzing slot can be enhanced by several times. The total current efficiency in the electrolysis process can reach 170%, and the selectivity of the anode and the cathode exceeds 95%.
Description
The present invention relates to method for preparing glyoxalic acid, relate in particular to the method for the paired fixed-bed reactor electrolytic preparation of a kind of usefulness oxoethanoic acid.
Oxoethanoic acid is a kind of important fine chemical material, and its skeleton symbol is: CHOCOOH can be used to prepare fine chemical products such as vanillin food grade,1000.000000ine mesh, wallantoin.At present, the preparation of oxoethanoic acid has oxidation style and reduction method.Oxidation style mainly contains oxalic dialdehyde nitric acid oxidation method, oxalic dialdehyde hydrogen peroxide oxidation process and oxalic dialdehyde anode electrolysis oxidation style.The report of this respect has United States Patent (USP) 414673A and 4235684A etc.Reduction method mainly is the acid by electrolytic reduction of oxalic method.The report of this respect has United States Patent (USP) 3779875 and Chinese publication CN1281063A etc.Also has the disclosed paired electrode electrolytic process of Chinese publication CN1064111A in addition.
United States Patent (USP) 4146731 discloses a kind of technology for preparing oxoethanoic acid with the nitric acid oxidation oxalic dialdehyde, this technology is difficult to strict control reaction conditions, thereby the selectivity that is difficult to suppress side reaction, guarantees oxoethanoic acid, and the consumption of nitric acid is very big, residual considerable nitric acid is difficult for removing in the product.And nitric acid is to the seriously corroded of equipment, and the nitrogen protoxide that produces in the oxidising process causes serious environmental to pollute easily.
United States Patent (USP) 4235684A and 3779875 and Chinese publication CN1281063A report all be monolateral electrolytic process.Wherein United States Patent (USP) 4235684A report is produced oxoethanoic acid with the oxalic dialdehyde anonizing.The current density used owing to this technology is little (smaller or equal to 200 amperes per meter
2), electrolysing period is very long, and the yield of the current efficiency of this process and oxoethanoic acid also not high (being respectively 67%～85%, 66%～82%).This technology fails to realize industrialization so far.United States Patent (USP) 3779875 and Chinese publication CN1281063A report with oxalic acid cathodic reduction legal system and are equipped with oxoethanoic acid.Though the current efficiency of used current density of this technology and electrolytic process and oxoethanoic acid chemistry selectivity are all higher, but since in the oxalic acid cathode reduction process anodic reaction for analysing oxygen, anodic process fails effectively to utilize, so this technology fails to give full play to the electrolysis advantage.
China publication CN1064111A has reported with paired electrode electrolytic synthesis oxoethanoic acid.Compare with monolateral electrolytic process, because cathode and anode all produces oxoethanoic acid, thereby the total current efficient of this method and the throughput of electrolyzer all are improved.But also there is following weak point in this technology:
1. the flow velocity of electrolytic solution big (＞1 meter per second).Will reach so high linear flow speed in suitability for industrialized production, the energy consumption of power system will be very surprising and be difficult to bear, and flow velocity is too high that production equipment and pipeline are had higher requirement.
2. little (800～900 amperes per meter of the current density of electrolytic process
2).Because this technology must satisfy the requirement of the low current density of anodic process, so the electrolyzer overall throughput not have raising to reduce the throughput of cathodic process on the contrary, thereby increased the average production cost of oxoethanoic acid product.
3. the current efficiency of cathode and anode electrolytic process all lower (cathode efficiency about 50%, anodic current efficiency is less than 80%).
The objective of the invention is to a kind of method that in electrolyzer, prepares oxoethanoic acid, to improve the throughput and the current efficiency of electrolyzer by time-dependent current (density) mode with fixed bed anode and fixed bed cathode.
Design of the present invention is such:
Desire improves the throughput of electrolyzer, must improve the received current of electrolytic process.To reduce optionally character of current efficiency and oxoethanoic acid chemistry according to high current density in the electrolytic process, thereby when improving received current to reach the throughput that improves electrolyzer, must guarantee that to reduce electrode actual current density electrolytic process has higher current density and oxoethanoic acid chemistry selectivity by increasing electrode area.
Along with the carrying out of electrolytic reaction, oxoethanoic acid concentration is more and more higher in the electrolytic solution.When the electrolysis later stage, oxoethanoic acid concentration was higher, the high current density electrolysis will reduce the current efficiency and the oxoethanoic acid chemistry selectivity of cathode and anode process greatly.Therefore the present invention is according to the scheme of the variation employing time-dependent current density of oxoethanoic acid concentration in the electrolytic solution, and electrolytic reaction still kept higher current efficiency and oxoethanoic acid chemistry selectivity when the electrolysis later stage, oxoethanoic acid was dense with assurance.
According to above-mentioned design, the present invention proposes technical scheme as described below:
The initial composition of electrolyte temperature, cationic exchange membrane and electrolytic solution that the present invention is used is all with reference to United States Patent (USP) 4235684 and Chinese publication CN1281063A.The manufacturing of fixed bed electrode electrolyzer is with reference to Chinese publication CN1083871A.
The said technology of the present invention comprises two steps of purifying of separating of paired electrolysis process and oxoethanoic acid head product.
(1) paired electrolysis process:
With oxalic dialdehyde, hydrochloric acid and disposable all the joining in the anode mixture groove of deionized water form anolyte; The disposable whole addings of composite additive and deionized water, the disposable whole addings of oxalic acid particle or regularly add in the cathode dissolution groove in batches and form catholyte to guarantee that oxalic acid solution is in state of saturation all the time, reduce the possibility of liberation of hydrogen; With anolyte recycle pump and catholyte recycle pump anolyte and catholyte are sent into the fixed bed electrode electrolyzer respectively and be carried out to electrolytic reaction, reaction formula is:
Anodic reaction:
Cathodic reaction:
The anolyte and the catholyte of the oxoethanoic acid that containing responds generates are sent back to anode mixture groove and cathode dissolution groove respectively.So repeatedly circulation, oxoethanoic acid content reaches the requirement of process stipulation in electrolytic solution.The separation and purification device that cathode and anode electrolytic solution is sent into respectively separately separates purification.
According to the conception of front, can reduce the electrode apparent current density by increasing electrode area.If by increasing the length and the wide increase that realizes the electrolysis area of electrode, so this method is also uneconomical, can not tackle the problem at its root.Compare with flat pole, fixed bed electrode is a kind of three-diemsnional electrode, has that surface-area is big, apparent current density is big, bed structure is compact, electrolyzer space-time rate advantages of higher.Adopt the fixed bed electrode electrolyzer under the situation of the length and width size that does not increase electrolyzer, to improve the electrolysis area of electrode.Thereby thereby the low current density of keeping electrolytic process under the situation that improves Faradaic current guarantees that whole electrolytic process has higher average current density and oxoethanoic acid selectivity.
Discover in anolyte compartment (oxalic dialdehyde oxidation synthesis glyoxylate process), when electrolysis arrives the later stage is the very high and glyoxal content of oxoethanoic acid content when extremely low, and the high current density electrolysis will cause the current efficiency of this process and oxoethanoic acid chemistry selectivity to descend significantly.This also is whole electrolytic process current efficiency and the not high major cause of oxoethanoic acid chemistry selectivity under the high current density condition.For this reason, the present invention has adopted time-dependent current (density) electrolysis mode, i.e. electrolysis adopts large-current electric to separate in earlier stage when the very high and oxoethanoic acid content of glyoxal content is not high; Along with the electrolytic more and more higher and glyoxal content of oxoethanoic acid content of carrying out in continuous decline, when electrolysis arrives to a certain degree, use little electric current instead and carry out electrolysis.So both can guarantee that whole process had higher mean current (density), can guarantee again that whole electrolytic process had very high current efficiency and oxoethanoic acid chemistry selectivity.Find that simultaneously because oxoethanoic acid content is very high in the electrolysis later stage catholyte, the high current density electrolysis also will cause oxoethanoic acid to be reduced to the generation of oxyacetic acid and oxalic dialdehyde etc. side reaction in cathode compartment (oxalic acid reduction synthesizing glyoxalic acid process).Therefore for negative electrode oxalic acid reduction reaction, the electrolysis later stage adopts low current (density) electrolysis also will help current efficiency and the oxoethanoic acid chemistry optionally improves.
The current density range of electrolytic process is 1000～5000 amperes per meter
2If electrolysis initial stage current density is too high, though electrolytic reaction speed is very big, but, thereby cause the current efficiency of whole electrolytic process and oxoethanoic acid chemistry selectivity not ideal because the current efficiency that causes the electrolysis initial stage of side reaction and oxoethanoic acid chemistry selectivity are just not high.If the current density at electrolysis initial stage is too low, the throughput of so whole electrolytic process just is difficult to guarantee.In order to guarantee that there is higher current efficiency and oxoethanoic acid chemistry selectivity in the electrolysis later stage, the present invention has adopted alap apparent current density in the electrolysis later stage.Electrolytic process preferably carries out as follows:
1. oxoethanoic acid concentration and oxalic dialdehyde concentration ratio in the anolyte: 0～5: 1 current density: 1 * I
2. oxoethanoic acid concentration and oxalic dialdehyde concentration ratio in the anolyte: 5: 1～40: 3 current density: α * I
In the formula: concentration is mass percent, and I is a current density, amperes per meter
2,
α=0.3～0.9, preferable range are 0.5～0.7.
The average current density of whole like this electrolytic process reaches as high as 4500 amperes per meter
2
Involved in the present invention to current efficiency and oxoethanoic acid chemistry optionally be defined as:
The electric weight of the theoretical electric weight that current efficiency=the mole of acetaldehyde acid of generation unit consumes/generation unit mole of acetaldehyde acid actual consumption.
The oxalic dialdehyde of the growing amount of oxoethanoic acid selectivity=oxoethanoic acid (mole)/consumption or oxalic acid amount (mole).
(2) purification of oxoethanoic acid head product:
The above-mentioned cathode and anode electrolytic solution head product that contains oxoethanoic acid only needs to adopt respectively conventional reduction vaporization and filter at low temperature just can obtain satisfactory 40% oxoethanoic acid commodity (anode product: oxoethanoic acid content 〉=40.0%, glyoxal content≤3.0%, oxalic acid content≤3.0%; Negative electrode product: oxoethanoic acid content 〉=40.0%, oxyacetic acid content≤3.0%, oxalic acid content≤3.0%), the present invention does not repeat them here.
Fig. 1 prepares the oxoethanoic acid process flow sheet for paired electrolysis.
1-cathode dissolution groove 2-catholyte recycle pump 3-catholyte heat exchanger
4-fixed bed electrode electrolyzer 5-cationic exchange membrane
6-fixed bed cathode 7-fixed bed anode 8-anolyte recycle pump
9-catholyte separation and purification device 10-anode mixture groove
11-anolyte heat exchanger 12-anolyte separation and purification device
As seen from Figure 1, oxalic acid particle, compound additive and deionized water are dropped in the cathode dissolution groove 1, form catholyte; Glyoxal, hydrochloric acid and deionized water are dropped in the anode mixture groove 10, form anolyte. The cathode chamber and the anode chamber that catholyte and anolyte are sent into electrolytic cell 4 simultaneously with catholyte circulating pump 2 and anolyte circulating pump 8 carry out the paired electrolysis reaction, catholyte and the anolyte of the glyoxalic acid that containing responds generates are sent back to respectively after heat exchanger 3 and 11 heat exchange in cathode dissolution groove 1 and the anode mixture groove 10, sent into simultaneously electrolytic cell 4 again and carry out the paired electrolysis reaction after mixing. So repeatedly, sent into respectively at last separation and purification device 9 and 12 and carried out separation and purification. Whole electrolytic process preferably carries out electrolysis by above-mentioned current density change rule.
Below will the present invention is further illustrated by embodiment.
Embodiment 1
All percentage compositions among the embodiment are the quality percentage composition.
4 millimeters of fixed bed cathode thickness (leaded 99.99%), 4 millimeters of fixed bed anode thickness (DSA).Make barrier film with CM001 type cationic exchange membrane.Catholyte is that deionized water and industrial one-level oxalic acid and total content are 0.5% additive, and wherein tetraethylammonium bromide is 0.5 with heptyl tributyl ammonium chloride molar content ratio.Oxalic dialdehyde initial content 7% in the anolyte, hydrochloric acid initial content 5%.With magnetic drive pump electrolytic solution is carried out cyclical operation, flow velocity 0.14 meter per second of electrolytic solution, 10 ℃ of fixed bed cathode inlet temperatures, 30 ℃ of fixed bed anode inlet temperature, the electrode apparent current density of electrolytic process is 1600 amperes per meter
2(constant current density electrolysis).The electrolysis result is:
| Electrode vessel | The electrolysis head product is formed (%) | Current efficiency (%) | Oxoethanoic acid chemistry selectivity (%) | |
| Cathode compartment | Oxoethanoic acid oxalic acid | 6.82 5.40 | 80.4 | 86.1 |
| The anolyte compartment | The oxoethanoic acid oxalic dialdehyde | 7.33 0.51 | 65.8 | 74.0 |
Embodiment 2
30 millimeters of fixed bed cathode thickness (leaded 99.99%), 30 millimeters of fixed bed anode thickness (DSA).Make barrier film with CM001 type cationic exchange membrane.Catholyte is that deionized water and industrial one-level oxalic acid and total content are 0.5% additive, and wherein tetraethylammonium bromide is 0.5 with heptyl tributyl ammonium chloride molar content ratio.Glyoxal content 7% in the anolyte, content of hydrochloric acid 5%.With magnetic drive pump electrolytic solution is carried out cyclical operation, electrode apparent velocity 0.3 meter per second of electrolytic solution, 15 ℃ of fixed bed cathode inlet temperatures, 30 ℃ of fixed bed anode inlet temperature, the electrode apparent current density Changing Pattern of electrolytic process is:
1. oxoethanoic acid concentration and oxalic dialdehyde concentration ratio in the anolyte: 0～5: 1, current density: 3000 amperes per meter
2
2. oxoethanoic acid concentration and oxalic dialdehyde concentration ratio in the anolyte: 5: 1～40: 3, current density: 1500 amperes per meter
2
The average current density of whole electrolytic process is 2640 amperes per meter
2The electrolysis result is as follows:
| Electrode vessel | The electrolysis head product is formed (%) | Current efficiency (%) | Oxoethanoic acid chemistry selectivity (%) | |
| Cathode compartment | Oxoethanoic acid oxalic acid | 7.66 5.07 | 89.6 | 96.2 |
| The anolyte compartment | The oxoethanoic acid oxalic dialdehyde | 8.61 0.63 | 84.8 | 93.7 |
The above-mentioned cathode and anode electrolytic solution head product that contains oxoethanoic acid only needs to adopt respectively conventional reduction vaporization and filter at low temperature just can obtain satisfactory 40% oxoethanoic acid commodity (anode product: oxoethanoic acid content 〉=40.0%, glyoxal content≤3.0%, oxalic acid content≤3.0%; Negative electrode product: oxoethanoic acid content 〉=40.0%, oxyacetic acid content≤3.0%, oxalic acid content≤3.0%).
Claims (3)
1. the method for an electrolytic synthesis oxoethanoic acid comprises two steps of purifying of separating of electrolytic synthesis oxoethanoic acid and oxoethanoic acid head product it is characterized in that electrolytic process uses the electrolyzer with fixed bed yin, yang electrode;
Wherein: said fixed bed anode and cathode thickness are 4～50 millimeters, and the used current density range of electrolytic process is 1000～5000 amperes per meter 2.
2. the method for claim 1 is characterized in that, electrolytic process carries out as follows:
1. oxoethanoic acid concentration and oxalic dialdehyde concentration ratio in the anolyte: 0～5: 1 current density: 1 * I;
2. oxoethanoic acid concentration and oxalic dialdehyde concentration ratio in the anolyte: 5: 1～40: 3 current density: α * I;
In the formula: concentration is mass percent, and I is a current density, amperes per meter
2, α=0.3～0.9.
3. method as claimed in claim 2 is characterized in that, wherein α=0.5～0.7.
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| Application Number | Priority Date | Filing Date | Title |
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| CN 01105992 CN1247819C (en) | 2001-04-17 | 2001-04-17 | Paired electrolysis procss of preparing glyoxalic acid |
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|---|---|---|---|
| CN 01105992 CN1247819C (en) | 2001-04-17 | 2001-04-17 | Paired electrolysis procss of preparing glyoxalic acid |
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| CN1322859A CN1322859A (en) | 2001-11-21 |
| CN1247819C true CN1247819C (en) | 2006-03-29 |
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Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1303252C (en) * | 2004-02-26 | 2007-03-07 | 华东理工大学 | Process of preparing ethyl aldehydic acid by electrolyzing |
| CN101078128B (en) * | 2007-06-30 | 2010-08-18 | 广西壮族自治区化工研究院 | Method and device for preparing mannitol and potassium iodate by electrolysis in pairs |
| CN103628086B (en) * | 2013-12-04 | 2016-01-20 | 太原理工大学 | A kind of method of paired electrolysis synthesizing benzaldehyde and sorbyl alcohol, N.F,USP MANNITOL simultaneously |
| CN104328453A (en) * | 2014-11-05 | 2015-02-04 | 太原理工大学 | Method for paired electrosynthesis of benzaldehyde and tetramethyl piperidinol |
| CN112725825A (en) * | 2020-11-27 | 2021-04-30 | 东华工程科技股份有限公司 | Method for preparing glyoxylic acid by electrolyzing oxalic acid |
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