DE2359863A1 - METHOD FOR PRODUCING GLYOXYLIC ACID - Google Patents

Description

Process for the production of glyoxylic acid

(Addition to patent ..... ".."'., -

Patent application p 22 <fÖ 759.6- ^ 2),

The present invention relates to a new method for Production of glyoxylic acid by the cathodic reduction of Oxalic acid .. ■ -

In the main patent. .... ... (patent application

■ dung P 22 4-0 759.6-42) the use of certain nitrogenous Adujuvantien.as additives to the catholyte in the Production of glyoxylic acid by cathodic reduction of oxalic acid is described. These nitrogen-containing adjuvants make it possible in particular to:.

Commercially available oxalic acid for the "production of glyoxylic acid without them being recrystallized several times

must, 408826/1 142.

Oxalic acid of various origins to use without it it is necessary to give them a special cleaning treatment. undergo or regarding the type of device and the special precautionary measures are to be taken from ions originating therefrom meet,

the formation of hydrogen at the cathode during electrolysis of the Oxalic acid, which enables better electrical yields to be obtained (a decrease in electrical yields corresponds to the formation of hydrogen).

The present invention relates to the use of new nitrogen-containing adjuvants in the production of glyoxylic acid by cathodic reduction of oxalic acid.

In particular, the invention relates to a method which consists in electrolysis in an electrolysis device with a cathode of a cathode chamber, a separating diaphragm, ■ To carry out an anode chamber and an anode, -which the Cathode chamber contains a catholyte consisting essentially of an aqueous oxalic acid solution, characterized in that is that this catholyte is 0.00005 'to 1 Gew? o one Contains adjuvant from the following group: ■

a) The tertiary / mine of the formula:

b) The bitertiary amines of the formula:

(II)

409826/1142

c) The quaternary ammonium salts of the formula:

d) The quaternary ammonium salts of the formula:

in which the various symbols have the following meanings to have: .

R ₁₀ , R.., Rp denote a straight-chain or branched, saturated or unsaturated aliphatic hydrocarbon radical, where two of them may optionally also form a single saturated alkylene radical or an oxydialkyl radical.

or a radical which has several hydroxyalkylene linkages, for example radicals of the formula:

- (CH ₉ L - ΓC- (CHv ,.) ■ -j- OH, with η = 2 or 3 and m = 1, 1- J _m ^{up to 10} »

where at least one of the radicals FLi ₀ , R ₁ -, and R _{12 is} an aryl aliphatic radical, preferably a radical of the formula CgH ₁ - - Rq -, where Rq is a divalent, straight-chain or branched saturated or unsaturated aliphatic hydrocarbon radical and the totality of the radicals RI ₀ * R-im and R ^ pi ^m generally has less than 40 carbon atoms in total,

409826/1 U2: v

^R 13 ' ^R 14' ^R 15 ' ^R 16 ^{have one of the} meanings given for R io' ^R 11 ^{and R} 12, with the possibility for two of these radicals to form a single divalent radical together only for two radicals that are from carried on the same nitrogen atom; where the number of carbon atoms of these radicals R ₁ ^ * ^R i4 ' ^R 15 ^unc * ^R i6 wi ⁰ * ¹⁰⁰ * ¹ ' ³ ^ ⁶ ^ ⁶ ^ is defined; and the presence of an arylaliphatic radical among the • radicals R ^> R ^> R ^ c and R ^ g is not necessary,

R ^ ₇ is a divalent aliphatic or arylaliphatic hydrocarbon radical, the aliphatic chain or aliphatic chains of which can be interrupted by oxygen atoms, the free valences of the radical R ^ _{7 being carried} by aliphatic carbon atoms and the number of total carbon atoms for the radicals R. ^ ₇ , R ^, R-ic » ^R -ig ^unci R-17 is generally above 6 and below 40,

RQ »R-iq> ^R 20 ^{un <} ^ ^R 21 represent a straight-chain or branched, saturated or unsaturated aliphatic hydrocarbon radical, where two of them can optionally also together form a single saturated alkylene radical or an oxydialkylene radical,

or a radical which has several oxyalkylene linkages, for example radicals of the formula

0- (CH ₀ )

2'n

0H _? with η = 2 or 3 and m = 1 - 10,

where at least one of the symbols Rg, Rq, R ₂₀ , R ^, is a monovalent aromatic hydrocarbon radical which is either purely aromatic, arylaliphatic or aromatic with aliphatic, straight-chain or branched, saturated or unsaturated radicals as substituents, the entirety being

the radicals R ^ ₈ , ^r iq> ^R 20 ^vjc1 ^ ^R 21 ^{in the al]} -S ^{one has} more than 15 and less than 40 carbon atoms,

409826/1142

R ₂₂ , Rp ^> ^R 24 ' ^R 25' ^R 26 ^unc * ^R ? 7 have the same meanings as given for R ₁ ^, R ₁ a »R ^ c and R ^ g; and R ₂ Q has the same meaning as given for R ₁₇ ; where all of the radicals R ₀₀ , R ₀ ^, R ₀ /, * Roe >> R _{O (} r, R ₀ ^ "and R _OQ in general

C-C- <-D CPr t-D CJO C. (CJO

has more than 8 and less than 40 carbon atoms, y means ¥ ert 1,2 or 3.

means a hydroxyl radical or an anion such that AH represents an inorganic or organic acid.

The precise nature of A ^y is a characteristic of the invention and one such anion can be replaced by another according to conventional ion exchange techniques. A possible meaning for A ^y apart from a hydroxyl radical is the nitrates ; Sulfates, phosphates, sulfonates, dicarbonates, oxalates, halides and especially the chlorides bromides and iodides.

The adjuvants used according to the invention are mainly those which are soluble in water at the concentration in question; in particular, it is preferred ^{to choose A y} ^ so that this solubility is present.

As adjuvants that can be used, one can especially name: That Tribeiizylamine, (Dimethylamine) ethyl ether, the hydroxides and salts, especially the halides of

Dimethyl-benzyl-dodecylammonium, diethyl-benzyl-dodecylammonium, Dimethyl-benzyl-tetradecylammonium, diethyl-benzyl-tetradecylammonium, Dimethyl-benzyl-hexadecylammonium, - diethyl-benzyl-hexadecylammonium, Dimethyl-benzyl-octadecylammonium, diethyl-benzyl-octodecylammonium, Dimethyl-benzyl-eicosylammonium, diethylbenzyl-eicosylammonium, dimethyl-benzyl-docosylammonium, diethylbenzyl-docosylammoniumj the hydroxides and salts of dimethyl

409 826/1 1 4 2

phenyl-dodecylammonium, dimethyl-phenyl-hexadecylammonium; the hydroxides and salts, especially the dihalides of 1,6- (triethylammonium) -hexane, 1,4-di- (n-butyl) -1,4-diazonia-bicyclo [2..2.2.] oqXqxl, 1,4 -Di- (n-dodecyl) -1,4-diazonia-bicyclo [2.2.2] octane ( cf. Examples 8 and 9).

The temperature of the catholyte is generally between ⁰ and 70.degree. C., preferably between 5 and 35.degree.

As metals that the cathodes in the process according to the invention can form, one can mainly lead, cadmium, mercury and the amalgams, as well as the alloys of these name different metals, especially with silver, tin and antimony. The anode of the electrolytic cells used in the invention consists in practice of an electrically conductive 'electrochemical' in the anolyte and among those in question drawn working stable material. Metals can be used as materials that are suitable for the anode and metalloids, such as platinum, platinum-coated titanium, graphite, lead and its alloys, especially with silver, Antimony and tin, 'name.

The separating diaphragm of the anode and cathode chambers is preferred a cathion exchange membrane. The nature of the same is not a characteristic of the invention. So you can all known Use membranes, especially the homogeneous membranes and the heterogeneous membranes. These membranes can possibly reinforced by an insert. In order to be able to carry out electrolysis operations of long duration, it is preferred, membrane! to use under the action of the various constituents of the catholyte and the anolyte are stable and do not swell. The membranes which can be used can in particular be those described in US Pat. No. 2,681,320 and in French patents 1 568 994, 1 575 782, 1,578,019, 1,583,089, 1,585,187 and 2,040,950.

409826 / 1U2

The permselectivity of the membranes used (measured as in French patent specification 1 584 187) is preferably over 60? ό.

The catholyte used in the process according to the invention contains essentially

Water .

Oxalic acid

Gryoxylic acid. ■ "

one or more adjuvants of one of the formulas I to IV

optionally a strong mineral acid such as sulfuric acid; rnan however, prefers not to use such an acid.

At the beginning of the electrolysis, the catholyte can only contain oxalic acid without glyoxylic acid; likewise the catholyte can only at the end of the electrolysis. Contains glyoxylic acid without oxalic acid. The concentrations of oxalic acid and glyoxylic acid can be constant, ¹ if you work continuously, or variable, if you work dis- ■ continuously, or even while a continuous process is being started. The concentration of oxalic acid is lower than the saturation at the temperature considered; In general, this concentration is more than 2% by weight; This value relates in particular to the constant concentration when working continuously and - the final concentration - ■ when working discontinuously. The concentration of glyoxylic acid is generally 3 to 25% by weight, preferably 5 to 15% by weight, these values relating in particular to the constant concentration of glyoxylic acid during a continuous process and the final concentration of this acid in the case of discontinuous work. As already stated above, the concentration of the adjuvant in the catholyte is generally between 0.00005 and 1% by weight. This concentration is preferably between 0.0001 and O _s 5%. The use of these small amounts has the advantage of removing

. 409826/1 142

of the adjuvant from the glyoxylic acid produced since this adjuvant then has practically no adverse effect on the qualities of this acid.

The catholyte can optionally also contain reaction by-products in small amounts, generally below Λ%.

An aqueous acidic solution is preferably used as the anolyte. The exact nature of this ariolyte is not a characteristic of the invention, since the main purpose of the anolyte is to increase the electrical conductivity between the two electrodes to ensure. In general, aqueous sulfuric acid and phosphoric acid solutions are used. The concentration of these solutions is generally between 0.1 and 5 mol / l, preferably between 0.5 and 2 mol / l.

The current density at the cathode is generally between

ρ ρ

3 and 50 A / dm, preferably between 10 and 35 A / dm.

All known ones can be used in practicing the invention Electrolysis devices, for example those in the above-mentioned patents and in particular the Belgian patent 757 106 described, use / ends.

However, it is preferred to use electrolyzers with fixed electrodes, which enables the realization of compact devices, in particular devices of the filter press type, enables. The electrodes and the separating diaphragm are advantageously arranged in parallel planes.

In a likewise advantageous manner, the catholyte and the anolyte can circulate in their respective chambers, which enables better results to be achieved.

Finally, between the electrodes and the separator

A09826 / 1U2

diaphragm separators or .. distance pieces, for example Arrange fabric or grid.

The following examples serve to illustrate the invention.

The "commercial" oxalic acid used in the "Examples" is an acid prepared according to the techniques described in French Patent 331 and British Patent 11 487/1915, the various reactions carried out leading to an oxalic acid solution which is dried in vacuo and then It is an oxalic acid dihydrate with a purity of about 99.2%.

Examples 1 to 9 " ^:

A number of attempts are made to reduce oxalic acid; these various attempts differ in the nature of the adjuvant used. The electrolysis cell in which these tests are carried out _f has the following characteristics ^!

The two electrodes are rectangular lead plates.

The usable surface of these electrodes is 0.8 dm.

The cathion exchange membrane is of the heterogeneous type: crosslinked sulfonated styrene ^J divinylbenzene copolymer, dispersed in a material made of polyvinyl chloride reinforced by an insert in the form of a fabric.

Permselectivity, measured "in 0.6 m-KCT: 77.5 #>.

Substitution resistance, measured in 0.6 m-KCl; 7 ohm.cm. Distance between electrode and membrane: 3 mm. - "Two pumps ensure the circulation of the catholyte and of the anolyte in the corresponding chambers of the cell.

409826/1142

- ίο -

The circles in which the anolyte and the catholyte circulate each have an expansion vessel with supply and Discharge lines is equipped.

There is also a heat exchanger in the circuit of the catholyte intended.

The electrolysis conditions are as follows:

Current density: 25 A / dm ² ■

Voltage: about 5.25V

Temperature: 25 ° C

Circulation speed of the electrolytes on the electrodes:

1 m / sec.

Catholyte introduced at the beginning: 2 l of an 8% strength by weight aqueous

Oxalic acid solution (commercially available oxalic acid).

This solution is electrolyzed in a continuous manner.

After one hour, 25 g of commercially available oxalic acid are added to the catholyte, followed by 25 g of this acid every half hour to.

During this entire period of time, the hydrogen escaping as gas is collected in a water trough and the current yield is monitored, which corresponds to this evolution of hydrogen gas. When this yield reaches a value of 6 to 12% , the special adjuvant is added to the catholyte in each experiment. The volume of hydrogen generated is measured in the hour following the addition of the adjuvant and the corresponding current efficiency is calculated. The results obtained with the various following adjuvants are shown in the tables below:

40 98 26/1142

.409826 / 1142

Table 1.

3example

Type of adjuvant

Duration of electrolysis before adding the adjuvant

Current yield (in %) corresponding to the Hp production at the time of the addition of the Äd.iuvans

Conc en.tr at i on
of the adjuvant in
mM / 1 in, the catholyte
his encore

Average current efficiency (in%) in the hour following the addition of the adjuvant

1 ^: N (CH ₂ -C ₆ H, -) * 2 h 15 ma " * 8th; · ' ϊ . .1. ¹ · '
. ■ * ■ : 2 : IT (Ci hh '"* , 2 h 20 ina "· S. 8.4 ' •
i
• 5 "" ' , ■ '· "■.. 5.1
■ * ■ ', ■ ·
* ·.
j * 1 ■■■ ■ s ■ •

5 i. 43 ma

: ° i

3.2

3 h 20 mn

, CH, -
ί ^Ο ΐ2 ^Η 25

2.8

3.9

: CH-iC ^^ OH '

20 ma

8.9.

4.7

C Cj C C C

In the tables, the abbreviation mM means millimoles.

40982 6/1 U2

Table 2

Example:

Type of adjuvant

Duration of electrolysis before adding the adjuvant

Current yield (in %) corresponding to the Hp generation at the time the adjuvant was added

concentration
of the adjuvant in
rsMA in the catholyte
his encore

Mean current yield (Xn%)
in the on the
Adding the adjuvant following
hour

. CH,. C-H- \ / ö5

. CH_ - H ^

■ w / approx

45

6.4

2.6

: ι J f \

2Br tv

5h.

ι ■. :

2I

2 Ii 18 mn

9.5

6.5

• CH-S / 2

-CE

2Ι

3 ii

7.2

1.5

*: co I ^er1

Claims (2)

1. Process for the production of glyoxylic acid by cathodic reduction of oxalic acid by carrying out electrolysis in an electrοIysevorrichtung with a cathode, a cathode chamber, a separating diaphragm, an anode chamber and an anode, the cathode chamber consisting essentially of an aqueous solution of oxalic acid contains existing catholytes, characterized in that the catholyte 0.00005 to Λ% einer.Adjuvans or an additive from the group of a) tertiary amines of the formula ■. «It b) bitertiary amines of the formula c) quaternary ammonium salts of the formula • ·> ■■ · ■ ;; ·· Ao 40 9 826/1 142 d) quaternary ammonium salts of the formula ₂₈ -H-H ₂₆ / ^ contains, wherein R _{1 is} Q, R ₁₁ , R ₁₂ saturated or unsaturated, straight-chain or branched, aliphatic hydrocarbon radical, where two of these radicals optionally together form a single saturated alkylene radical or an oxydialkylene radical can, or a radical which has several oxyalkylene linkages, such as of the formula - (CH ₅ ) - To- (CH ₅ ) 4- OH, with η = 2 or 3 and m = 1 to mean, where at least one of the radicals R ^ ₀ * ^R n ^{and R} i2 is ^a phatic radical, preferably a radical of the formula CgHj- - Rq -, where Rq is a divalent saturated or unsaturated, straight-chain or branched aliphatic hydrocarbon radical and the entirety of the i ^m generic radicals P in 'R ^ ₁ and R 2 is less than a total of 40 carbon atoms, ^R 13 ^'R 14 ^R 15 * ¹¹ ^ ^ ^R ^ ^{he a} 16 for Rq, possess the above R ₁₁ and R ₁ P meanings given, with the possibility 409826/1142 for two of these radicals, together to form a single divalent radical, only exists for two radicals which are carried by the same nitrogen atom; where the number of carbon atoms of the radicals R ^ .- z »^ -14» ^R 15 ^{un (} ^ ^ 16 is ^as defined below -; and the presence of an aryl aliphatic radical. Among the radicals TU * »R-ia» R <cj ^{uncJ R} - | 6 is not necessary, R _{17 is} a divalent aliphatic or arylaliphatic hydrocarbon radical, the aliphatic chain or aliphatic chains of which can be interrupted by oxygen atoms, the free valences of the radical R ₁₇ from. aliphatic carbon atoms are carried and the total number of carbon atoms of the radicals R, .- ,, R, .., R ^ c, R-ig and R ₁₇ is generally above 6 and below 40 ,. 21 ^ ^e ^ ^NEN saturated or unsaturated, linear or branched aliphatic hydrocarbon radical represented, whereby two of these radicals together may form a single alkylene group or saturated, an oxydialkylene or optionally a radical which comprises several Oxyalkylenverkettungen as radicals of the formula - (CH ₂ ) _n -p- ( ^CH 2) _n T ^0H > ^{with n} = 2 or 3 and m = 1 to ^{L Jm} 10, where at least one of the symbols R ^ _Q , Rq, Rp ₀ and R ^ is a monovalent aromatic carbon radical which is either purely aromatic, arylaliphatic or aromatic with linear or branched, saturated or unsaturated aliphatic radicals as substituents, and the total · integral of the radicals R _8, R ^ o, R ₂ ^{Q, and R} 21 ^{in all} g ^emeinen more than 15 and less than 40 carbon atoms, 409826/1 U2 ^R 22 ^{;> R} 23 ' ^R 24' ^R 25 ' ^R 26 ^{and R} 27 have ^{the same} meanings as given for R ₁₃ , R ^, ^R 15 and R ₁₆ ; and R _{28 has} the same meaning as indicated for R ^ "? and all of the radicals Rg ₂ J ^ 23 »^ 24 * ^R 25 * ^R 26 ' ^R 27 ^{UX1 (} ^ Rgg generally has more than 8 and less than 40 carbon atoms» y has the meaning of 1, 2 or 3, represents the hydroxyl radical or an anion, so that AH means inorganic or organic acid, 2., method according to claim 1 ,. characterized _r _ that the adjuvant is soluble in water at the considered concentration * - 3, method according to one of claims 1 or 2, characterized in that it is identified;.,. öasa <tes Adäii ^ ans is selected from the group t (BimethylaiainQO ^ thylätherj the hydroxy and especially the Djim halides, ¥ on dimethyl-benz.ylmi üiäthyl-benzyl-dodeeylammonium. Dimethylb © B syl "" fc e tr ade CYJ amraoriium, 131 ätliyl -ΐ> enzyl -1 etr ad e ey 1 ammonium, Bimethyl-benzyl-hexadecylammQniumj ,. diethyl-benzyl-ammonium hexadeGyl-. Dimethylr-benzyl ^ oQtadeGylaminonium, diethyl-benzyl 'oetQdeoylaißiBoniumj dimethyl-benz.yl-r-eicosylainmQnium, diethyl benzyl-dimethyl ^ _t .eieosylammonium benzyl-doco-sylammonium, diethyl-benzyl-docosylammonium j the hydroxides and salts of dimethyl-phenyl-dodecylammonium, Dimethyl-phenyl-hexadecylammonium; the hydroxides and Salts, especially the dinalogenides of 1,6- (triethylammonio) -hexane, 1,4-Di (n-butyl) -1,4-.diazonia ~ bicyclo [2.2.2] octane, 1,4-di (n-dodeoyl) -1 ^ - 409826/1142