Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B3/00—Electrolytic production of organic compounds
  • C25B3/20—Processes
  • C25B3/25—Reduction
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B3/00—Electrolytic production of organic compounds
  • C25B3/01—Products
  • C25B3/07—Oxygen containing compounds

Definitions

• ABSTRACT 30 Foreign Application priority Data
• Glyoxylic acid is obtained by cathodic reduction of Dec 1 1972 France 72 42836 oxalic acid m the presence of a tertiary amine or a quaternary ammonium salt.
• the presence of the ni- [52] CL 204/77 2O4/75 204/76 trogeneous compound allows efficient reduction to [51] Int I CZSB 3/04 take place using a commercial unpurified oxalic acid.
• the present invention involves the use of new nitrogen-containing adjuvants in the preparation of glyoxylic acid by cathodic reduction of oxalic acid.
• the present invention provides a process for the preparation of glyoxylic acid by cathodic reduction of oxalic acid, by carrying out an electrolysis in an electrolyser comprising a cathode, a cathode compartment, a separating diaphragm, an anode and an anode compartment wherein the said cathode compartment containing a catholyte consisting essentially of an aqueous solution of oxalic acid and 0.00005 to 1% w/w of an adjuvant chosen from:
• R R and R each represent a linear or branched, saturated or unsaturated, aliphatic hydrocarbon radi- 2 cal, or two of R R and R together represent a single saturated alkylene or oxydialkylene radical, or R R and R can each represent an aliphatic radical containing at least one oxyalkylene link, at least one of the readicals R R and R being an arylaliphatic radical, the'radicals R R and R together having less than 40 carbon atoms;
• R ,R ,R and R each represent linear or branched saturated or unsaturated aliphatic hydrocarbon radicals, or an aliphatic radical containing at least one oxyalkylene links or at least one of R and R together or R and R together represent a single alkylene or oxydialkylene radical,
• R represents an aliphatic or arylaliphatic, divalent hydrocarbon radical, the aliphatic chain or chains of which can be interrupted by oxygen atoms, the free valencies of the radical R being carried by aliphatic carbon atoms, and the total number of carbon atoms in the radicals R R R R and R being greater than 6 and less than 40;
• R R R and R each represent a linear or branched, saturated or unsaturated, aliphatic hydrocarbon radical, or an aliphatic radical containing at least one oxyalkylene links, or two of R R R and R together form a single saturated alkylene or oxydialkylene radical,
• R R R and R being a monova lent aromatic hydrocarbon radical which is either purely aromatic, or arylaliphatic, or aromatic and having as substituents saturated or unsaturated, linear or branched, aliphatic radicals, the total number of carbon atoms in R R R and R being more than 15 and less than 40;
• R R R R R and R are as defined for R R R and R and R is as defined for R the total number of carbon atoms in R R R R R R and R being more than 8 and less than 40;
• A" is hydroxy or an anion such that AH represents an inorganic or organic acid.
• the arylaliphatic group R R and/or R may be of formula C l-l R where R is a linear or branched saturated or unsaturated, aliphatic divalent hydrocarbon radical.
• A is not critical and such an anion can be replaced by another in accordance with the conventional techniques of ion exchange; as a possible value of A" in addition to the hydroxyl radical, there may be mentioned nitrates, sulphates, phosphates, sulphonates, bicarbonates, oxalates and halides, and especially chlorides, bromides and iodides.
• the adjuvants used in the invention are essentially those which are soluble in water at the concentration considered, and in particular it is preferred to choose A" so as to achieve this solubility.
• the temperature of the catholyte is generally be tween and 70C, .and preferably between and C.
• Metals which are capable of forming the cathodes of the process of the invention include principally lead, cadmium, mercury and amalgams, as well as the alloys of these various metals, particularly with silver, tin and antimony.
• the anode of the electrolysis cells used in the invention consists, in practice, of a material which conducts electricity and which is electrochemically stable in the anolyte and under the working conditions considered. Materials which are thus suitable for forming the anode, include metals and metalloids such as platinum, platinised titanium, graphite and lead and its alloys, particularly with silver, antimony and tin.
• the separating diaphragm between the anode and cathode compartments is preferably a cation exchange membrane.
• a cation exchange membrane The nature of the latter is not characteristic of the invention; thus any known membrane can-be used, and in particular membranes of the homogeneous type and membranes of the heterogeneous type; these membranes can optionally be reinforced with a screen; for the purpose of being able to carry out electrolysis operations of long duration, it is naturally preferred to use membranes which do not swell and which are stable to the action of the various constituents of the catholyte and the anolyte.
• membranes which can be used there may mentioned more particularly those described in the following patents:
• the permeation selectivity of the membranes used is preferably greater than 60%.
• Thecatholyte used in the process according to the invention comprises essentially:
• a strong inorganic acid such as sulphuric acid; however, it is preferred not to use such an acid.
• the catholyte can contain oxalic acid without glyoxylic acid only at the start of electrolysis; in the same way, the catholyte can contain glyoxylic acid without oxalic acid only at the end of electrolysis.
• concentrations of these oxalic and glyoxylic acids can be either constant when the reaction is carried out continuously, or variable when the reaction is carried out discontinuously or during the starting of a continuous operation. In all cases, the concentration of oxalic acid is less than the saturation value at the temperature considered; generally, this concentration is greater than 2% by weight; this value relates particularly to the constant concentration when the reaction is carried out continuously and to the final concentration when the reaction is carried out discontinuously.
• the concentration of' glyoxylic acid is usually between 3 and 25% by weight, and preferably between 5 and 15%-'by .weight,.these values relating particularly to the constant concentration of glyoxylic acid when thereaction is carried out continuously and to the final concentration of this same acid when the reaction is carried out discontinuously.
• the concentration of adjuvant in the catholyte is 0.00005 to- 1% by weight. This concentration is preferably 0.0001 to 0.5%; the use of these small amounts has the value of making it possible to refrain from removing the adjuvant from the glyoxylic acid produced, as this adjuvant then exerts practically no harmful effect on the properties of the said acid.
• the catholyte can, optionally and in addition, contain reaction by-products in small amounts, generally less than 1%.
• An aqueous acid solution is preferably used as the anolyte.
• the precise nature of thisanolyte is not characteristic of the invention because the purpose of the said anolyte is essentially to provide electrical conductivity between the two electrodes.
• Aqueous solutions of sulphuric or phosphoric acids are usually employed. The concentration of these solutions is generally between 0.1 and 5 mols/litre, and preferably between 0.5 and 2 mols/ litre.
• the current density at the cathode is generally'3 to 50 A/dm and preferably 10 to 35 A/dm.
• electrolysersof any known type can be used, for example, those of the patents mentioned above and especially Belgian'Pat. No. 757,106. 3
• electrolysers with solid electrodes, which makes it possible to produce compact apparatuses, especially of the filter press type.
• the electrodes and the separating diaphragm are ad'- vantageously arrang'ed in parallel plane's.
• the catholyte and the anolyte can be circulated in their respective compartments, which makes it possible t o achieve better results.
• spacers for example woven fabrics or grids, can be provided between the. electrodes and the separating diaphragm.
• the commercial oxalic acid used in the examples is an acid prepared according to the techniques described in French Pat. No. 331,498 and British Pat. No. 1 1,487/1915; the various reactions carried out give an oxalic acid solution which is dried in vacuo and then drained it is an oxalic acid dihydra'te with a degree of purity of about 99.2%.
• the two electrodes are rectangular lead plates
• the useful surface area of these electrodes is 0.8 dm
• the cation exchange membrane is of the heterogeneous type, consisting of a crosslinked sulphonated styrene/divinylbenzene copolymer, dispersed in a polyvinyl chloride matrix, and is reinforced with a screen in the form of a woven fabric.
• quaternary ammonium salts of the general formula sent a single saturated alkylene or oxydialkylene radical, or R R and'R can each representan- R ,',R, ;:R and R each represent a linearor branched, saturated or unsaturated, aliphatic hydrocarbon radical, or an aliphatic radical containing at'leas'tone oxyalkylene links,.or,twoof R R, .R 'and;R' together form a single saturated alkylene o'r oxydialkylene radica l,.
• R -R R and R being a rnonova-,-
• R R and-R is an arylaliphatic radical of formula C l-i 4 R where R9 is a linear or branched saturated or -unsa'turated aliphatic divalent hydrocarbon radical.
• the adjuvant is selected from tribenzylamine; (dimethylamino)-ethyl ether; dimethyl-benzyl-dodecyl-ammonium,. diethylbenzyl-dodecyl-ammonium, dimethyl-benzyl-tetradecyl-ammonium, diethyl-benzyl-tetradecyl-ammonium, dimethyl-benzyl-hexadecyl-ammonium, diethyl-benzylhexadecyl-amm'onium, dimethyl-benzyl-octadecyl ammonium," diethyl-benzyl-octadecyl-ammonium, di-
• R R R arid R each .represent linear or branched saturated-or unsaturated aliphatic hydrocarbon radicals, or an aliphatic radical containing I l,4-diazoniadicyclo[2,2,2]octane syl-ammonium, dimethy]-benzyl-docosyl-ammonium H and diethyl-benzyl-docosyl-ammonium hydroxides and salts; dimethyl:phenyl-dodecyhammonium and dimethyl-phenyI hexadecyl-ammonium hydroxides and salts; and l,6-(triethylammonio)-hexane, l,4-di-(n-butyl)- and l ,4-di-(ndodecyl)- l ,4-diazoniadicyclo[2,2,21octane hydroxides and salts.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Electrochemistry (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Applications Claiming Priority (1)

Publications (1)

Family

ID=9108075

Family Applications (1)

Country Status (12)

Cited By (7)

Citations (3)

Family Cites Families (2)

• 1972
  • 1972-12-01 FR FR7242836A patent/FR2208876B2/fr not_active Expired
• 1973
  • 1973-11-23 NL NL7316069A patent/NL7316069A/xx not_active Application Discontinuation
  • 1973-11-28 BR BR9344/73A patent/BR7309344D0/pt unknown
  • 1973-11-29 JP JP48134014A patent/JPS5046624A/ja active Pending
  • 1973-11-30 GB GB5571973A patent/GB1446179A/en not_active Expired
  • 1973-11-30 US US420576A patent/US3929613A/en not_active Expired - Lifetime
  • 1973-11-30 CA CA187,122A patent/CA1022496A/fr not_active Expired
  • 1973-11-30 BE BE138410A patent/BE808087A/xx unknown
  • 1973-11-30 IT IT31994/73A patent/IT1002168B/it active
  • 1973-11-30 CH CH1687173A patent/CH590815A5/xx not_active IP Right Cessation
  • 1973-11-30 AT AT1005273A patent/AT331774B/de active
  • 1973-12-03 DD DD175054A patent/DD108265A5/xx unknown

Patent Citations (3)

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