Method for hydroformylation of unsaturated compounds
The invention relates to a method for hydroformylation of unsaturated compounds such as olefins and alkynes using mixtures of synthesis gas (CO/H 2 ), in which either the unsaturated compounds and a catalyst are heated to a reaction temperature of 60 to 200° C. and the synthesis gas is then added, or the unsaturated compounds and the catalyst are brought into contact with pure CO at normal temperature in a preformation step, then are heated to reaction temperature and on reaching the reaction temperature the CO is replaced by the synthesis gas. The pressure is 1 to 200 bar and the CO:H 2 ratio in the synthesis gas is in the range from 1:1 to 50:1. The iridium catalyst used comprises a phosphorus-containing ligand in the iridium:ligand ratio in the range from 1:1 to 1:100. With high catalyst activities and low catalyst use, very high turnover frequencies are achieved.
1. A method for hydroformylating an unsaturated compound with a synthesis gas mixture comprising carbon monoxide and hydrogen, the method comprising:
(a1) heating the unsaturated compound and a catalyst to a reaction temperature of 60 to 200° C. and
(a2) adding the synthesis gas
or
(b1) contacting the unsaturated compound and the catalyst with pure carbon monoxide at normal temperature in a preformation step,
(b2) heating the mixture to a reaction temperature of 60 to 200° C. and
(b3) on reaching the reaction temperature, replacing the carbon monoxide with the synthesis gas mixture,
where a reaction pressure is in a range from 0.1 to 20.0 MPa, a CO:H 2 molar ratio in the synthesis gas mixture is in a range from 1:1 to 50:1 and the unsaturated compound is reacted in the presence of a polar solvent and of the catalyst, wherein the catalyst is an iridium catalyst comprising a ligand comprising phosphorus, wherein an iridium:ligand molar ratio is in a range from 1:1 to 1:100.
2. The method of claim 1 , wherein the CO:H 2 molar ratio in the synthesis gas mixture is in a range from 1:1 to 10:1.
3. The method of claim 1 , wherein the unsaturated compound is at least one selected from the group consisting of a terminal alkene, a cycloalkene, and an aromatic olefin having a carbon number between 2 and 20.
4. The method of claim 1 , wherein the polar solvent is water or an inert organic solvent.
5. The method of claim 1 , wherein a precursor salt or complex comprising iridium forms a catalytically active iridium(hydrido)(carbonyl) complex with the synthesis gas mixture and the ligand comprising phosphorus.
6. The method of claim 5 , wherein the precursor salt or complex comprises an Ir(I) halide, an Ir(II) halide, an Ir(I) carboxylate, an Ir(III) carboxylate, an Ir(III) iridate, or an Ir(IV) iridate, wherein iridium is present in an Ir-carbonyl, Ir-olefin, Ir-hydrido, Ir-arene or Ir-allyl complex in an oxidation state of −I to +V.
7. The method of claim 1 , wherein the ligand comprising phosphorus forms a monodentate or multidentate bond to an iridium center of the iridium catalyst, and the ligand is at least one selected from the group consisting of a phosphine, a phosphite, a phosphoramidite, a phosphonite, a phosphinite, a triarylphosphine, a trialkylphosphine, Xanthphos ((9,9-dimethyl-9H-xanthen-4,5-diyl)bis(diphenylphosphine)), BINAP (2,2′-bis(diphenylphosphino)-1,1′-binaphthyl), and NaPhos (2,2′-bis((diphenylphosphino)methyl)-1,1′-binaphthyl).
8. The method of claim 1 , wherein the reaction is carried out at a reaction temperature of 80 to 200° C.
9. The method of claim 1 , wherein the reaction pressure is from 0.1 to 10.0 MPa.
10. The method of claim 1 , wherein the iridium:ligand molar ratio is in a range from 1:1 to 1:50.
11. The method of claim 1 , wherein the ligand comprising phosphorus is selected from the group consisting of triphenylphosphine, 2-(diphenylphosphino)-1-phenyl-1H-pyrrole, tricyclohexylphosphine and (11bS)-4-tert-butyl-4,5-dihydro-3H-dinaphtho[2,1-c:1′,2′-e]phosphepine.
12. The method of claim 3 , wherein 0.02 to 0.4 mol % of iridium is employed based on the olefin.
13. The method of claim 1 , wherein the unsaturated compound is at least one selected from the group consisting of a terminal alkene, a cycloalkene, and an aromatic olefin having a carbon number of 4 to 12.
14. The method of claim 1 , wherein the reaction is carried out at a reaction temperature of 80 to 180° C.
15. The method of claim 1 , wherein the reaction is carried out at a reaction temperature of 100 to 160° C.
16. The method of claim 1 , wherein the reaction pressure is from 1.0 to 5.0 MPa.
17. The method of claim 1 , wherein the iridium:ligand molar ratio is in a range from 1:1 to 1:8.
18. The method of claim 1 , wherein the unsaturated compound is a terminal alkene having a carbon number between 2 and 20.
19. The method of claim 1 , wherein the unsaturated compound is a cycloalkene having a carbon number between 2 and 20.
20. The method of claim 1 , wherein the unsaturated compound is an aromatic olefin having a carbon number between 2 and 20.