Process for producing delta-lactones
The present invention relates to a process for preparing a lactone. The process comprises the steps of reacting an aldehyde with an organic halide in a carbon chain extension reaction to form an alcohol compound comprising a functional group capable of allowing for carbonylation of said alcohol compound, and then reacting said alcohol compound in a carbonylation reaction to form an hydroxycarboxylic acid; and cyclizing the hydroxycarboxylic acid to produce the lactone.
1. A process for preparing a delta-lactone comprising the steps of
a) reacting an aldehyde with an unsaturated organic halide in a carbon chain extension reaction, wherein the carbon chain extension reaction is carried out in the presence of water, using a catalyst comprising a mixture of aluminum, copper, tin(II) chloride and sodium iodide or a catalyst comprising a mixture of copper and tin(II) chloride, to form an alcohol compound comprising a functional group capable of allowing for carbonylation of said alcohol compound;
b) reacting said alcohol compound with a source of carbon monoxide in a carbonylation reaction in the presence of water, using a catalytic system comprising a transition metal and/or a salt of a transition metal wherein the transition metal is selected from cobalt, iridium, palladium, platinum, rhodium, and mixtures thereof, wherein the catalytic system further comprises a tin(II) chloride co-catalyst and a ligand comprising at least one donor atom selected from nitrogen, phosphorous, arsenic, antimony and bismuth to form an hydroxycarboxylic acid; and
c) cyclising the hydroxycarboxylic acid to produce the delta-lactone.
2. A process for preparing a delta-lactone according to claim 1 , wherein the process further comprises a step:
d) purifying the delta-lactone.
3. A process for preparing a delta-lactone according to claim 2 , wherein step d) comprises distillation of the lactone.
4. A process according to claim 1 wherein the aldehyde compound is of Formula Iva,
wherein R 1A is a hydrocarbyl group, and R 1B is hydrogen.
5. A process according to claim 4 , wherein R 1A is a C 1 -C 8 alkyl group optionally substituted with one or more hydrocarbyl or oxyhydrocarbyl groups.
6. A process according to claim 4 , wherein R 1A is a C 5 -C 7 alkyl group.
7. A process according to claim 1 wherein the organic halide is an unsaturated halide of the Formula IIIb:
wherein R 2 , R 3 , R 4 , R 5 and R 6 are independently selected from a group comprising a hydrogen and a hydrocarbyl group; and X is a halide.
8. A process according to claim 7 , wherein R 2 , R 3 , R 4 , R 5 and R 6 are independently selected from a group comprising hydrogen and a C 1 -C 4 alkyl group.
9. A process according to claim 1 , wherein the organic halide is allyl chloride.
10. A process according to claim 1 , wherein the source of carbon monoxide is carbon monoxide.
11. A process according to claim 1 , wherein the source of carbon monoxide is formic acid.
12. A process according to claim 1 , wherein the source of carbon monoxide is oxalic acid.
13. A process according to claim 1 , wherein the carbonylation reaction catalytic system comprises palladium chloride.
14. A process according to claim 1 , wherein the carbonylation reaction catalytic system further comprises a ligand comprising at least one donor atom selected from nitrogen, phosphorous, arsenic, antimony and bismuth.
15. A process according to claim 13 , wherein the ligand is triphenylphosphine.
16. A process according to claim 1 , wherein carbonylation reaction is carried out at a temperature of from 80 to 140° C.
17. A process according to claim 1 , wherein carbonylation reaction is carried out at a pressure of from 1 to 150 bara.