Claims
- 1. Process for the preparation of esters of oxalic acid having the formula ROOC--COOR by oxidative reaction in the presence of palladium-based catalysts, characterized in that the oxalic esters are obtained by the reaction of a copper (II) compound having the formula Cu(OR)X, wherein R represents a radical selected from among alkyls having from 1 to 8 carbon atoms, and X is chosen from between chlorine and bromine atom, with carbon monoxide in the presence of a catalyst selected from the group consisting of Pd salts, metal Pd and zero valent Pd complexes, at a temperature of between 20.degree. and about 200.degree. C., in the absence of O.sub.2.
- 2. Process according to claim 1, characterized in that the catalyst consists of a Pd containing component selected from the group consisting of Pd halides, Pd nitrate, Pd acetate, Pd sulphate and Pd acetylacetonate, Pd on carbon and Pd complexes with phosphines and/or with dibenzylidene-acetone.
- 3. Process according to claim 1, characterized in that the catalyst consists of Pd acetylacetonate.
- 4. Process according to claim 1, characterized in that the copper (II) compound is Cu(OR)X, wherein R is a radical selected from the group consisting of alkyls having from 1 to 4 carbon atoms and X is either a chlorine or a bromine atom.
- 5. Process according to claim 1, characterized in that the reaction is conducted in a substantially anhydrous medium selected from the group consisting of monofunctional alcohols of formula ROH, wherein R is an alkyl having from 1 to 4 carbon atoms, benzene, acetone, ethylacetate, tetrahydrofurane and/or mixtures thereof.
- 6. Process according to claim 5, characterized in that an anhydrous medium is selected from the group consisting of methyl alcohol and ethyl alcohol.
- 7. Process according to claim 1, characterized in that the molar ratio of Pd with respect to the copper compound Cu(OR)X is comprised between 0.0001 and 0.1 mol of Pd per 1 mol of copper compound.
- 8. Process according to claim 1, characterized in that the reaction is conducted between about 50.degree. and 120.degree. C.
- 9. Process according to claim 1, characterized in that the reaction is conducted under partial CO pressures comprised between about 10 and 100 ata.
- 10. Process according to claim 1, characterized in that the carbon monoxide is fed in admixture with gases inert under reaction conditions.
- 11. Process according to claim 10 wherein the carbon monoxide is fed in admixture with H.sub.2 coming from the industrial preparation of the synthesis gas.
- 12. Process according to claim 4 wherein R is methyl and X is chlorine.
Priority Claims (1)
Number |
Date |
Country |
Kind |
22169 A/76 |
Apr 1976 |
ITX |
|
CROSS-REFERENCE TO RELATED APPLICATIONS
This is a continuation of copending application Ser. No. 783,047, filed Mar. 30, 1977, now abandoned.
US Referenced Citations (3)
Foreign Referenced Citations (1)
Number |
Date |
Country |
2213435 |
Oct 1973 |
DEX |
Continuations (1)
|
Number |
Date |
Country |
Parent |
783047 |
Mar 1977 |
|