Process for the production of ethylenically unsaturated carboxylic acids or esters
The present invention relates to a process for the production of an ethylenically unsaturated carboxylic acid or ester, preferably α,ß ethylenically unsaturated carboxylic acids or esters, by the liquid phase reaction of formaldehyde or a suitable source thereof with a non-cyclic carboxylic acid ester in the presence of a basic metal salt.
1. A process for production of an ethylenically unsaturated carboxylic acid or ester by a liquid phase reaction of formaldehyde or a suitable source thereof with a non-cyclic carboxylic acid ester of formula R 3 —CH 2 —COOR 4 in the presence of a basic metal salt, wherein R 4 is an alkyl group and R 3 is methyl wherein the basic metal salt is a group I or a group II metal salt.
2. The process according to claim 1 , wherein the basic metal salt is selected from group I or group II metal oxides, hydroxides, carbonates, hydrogen carbonates, methyl carbonates, alkoxides, fluorides and phosphates.
3. The process according to claim 1 , wherein the basic metal salt is selected from potassium oxide, caesium oxide, sodium oxide, rubidium oxide, barium oxide, potassium hydroxide, caesium hydroxide, sodium hydroxide, rubidium hydroxide, barium hydroxide, potassium phosphate, caesium phosphate, sodium phosphate, rubidium phosphate, barium phosphate, sodium methoxide, potassium methoxide, rubidium methoxide, sodium t-butoxide, potassium t-butoxide, rubidium t-butoxide, caesium t-butoxide, sodium fluoride, potassium fluoride, rubidium fluoride, caesium fluoride, potassium carbonate, caesium carbonate, sodium carbonate, rubidium carbonate, barium carbonate, potassium hydrogen carbonate, sodium hydrogen carbonate, rubidium hydrogen carbonate, caesium hydrogen carbonate, barium hydrogen carbonate, potassium methyl carbonate, sodium methyl carbonate, caesium methyl carbonate, rubidium methyl carbonate or barium methyl carbonate.
4. The process according to claim 1 , wherein the reaction is performed at a temperature below 300° C.
5. The process according to claim 1 , wherein the reaction is performed at a pressure of between 5 and 2000 psi.
6. The process according to claim 1 , wherein the suitable source of formaldehyde is selected from formalin, low molecular weight polyformaldehyde, gaseous formaldehyde, formaldehyde hemiacetal, trioxane or anhydrous formaldehyde.
7. The process according to claim 1 , wherein the process is a batch or continuous process.
8. The process according to claim 1 , wherein in a reaction medium the non-cyclic carboxylic acid ester is maintained in a molar excess compared to the formaldehyde or suitable source thereof.
9. The process according to claim 8 , wherein the formaldehyde or suitable source thereof is added to the reactor at a rate from about 1 to 10 mol %/minute relative to the non-cyclic carboxylic acid ester.
10. The process according to claim 8 , wherein a molar ratio of formaldehyde or suitable source thereof to the non-cyclic carboxylic acid ester is maintained at about 1:100 to 1:2 during the reaction.
11. The process according to claim 8 , wherein the formaldehyde or suitable source thereof is fed to a reactor in a molar ratio of 1.1:1 to 1:1 with the non-cyclic carboxylic acid ester.
12. The process of claim 1 , further comprising one or more solvents.
13. The process according to claim 12 , wherein the one or more solvents is wholly or substantially aprotic.
14. The process according to claim 13 , wherein the solvent is an aprotic protophilic solvent or an aprotic photophobic solvent.
15. The process according to claim 14 , wherein the solvent is selected from dimethyl formamide, diethyl formamide, dimethylacetamide (DMAc), 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone (DMPU), 1,3-dimethyl-2-imidazolidinone (DMEU or DMI), 3-methyl-2-oxazolidinone, propylene carbonate, diethylacetamide, 1-methyl-2-pyrrolidinone, hexamethylphosphoric triamide, pyridine, tetramethyl urea, dimethylsulfoxide, acetonitrile, propionitrile, benzonitrile, acetone, 2-butanone, 3-pentanone, acetophenone, nitromethane, nitrobenzene, tetrahydrothiophene 1,1-dioxide (sulfolane), diethyl ether, diisopropyl ether, 1,4-dioxane, dimethyl carbonate, tetrahydrofuran, 1,2-dimethoxyethane, diglyme, benzene, cyclohexane, xylene or toluene.
16. A process according to claim 1 , wherein the ethylenically unsaturated carboxylic acid or ester is an α,ß ethylenically unsaturated carboxylic acid or ester.