Propyl-bridged diphosphine ligands for alkoxycarbonylation
Propyl-bridged diphosphine compounds, metal complexes of these compounds and the use thereof for alkoxycarbonylation.
1. A metal-ligand complex comprising Pd and a compound of the formula (1)
wherein R 1 is t Bu and R 2 is -(C 1 -C 12 )-alkyl.
2. The complex according to claim 1 ,
wherein it has the structure (L1):
3. A process for preparing an ester comprising:
a) initially charging an ethylenically unsaturated olefin, thereby forming a reaction mixture;
b) adding a compound having the formula:
wherein R 1 and R 2 are each independently -(C 1 -C 12 )-alkyl,
and a compound comprising Pd;
c) adding an alcohol;
d) feeding in CO;
e) heating the reaction mixture, thereby converting the CO, alcohol and ethylenically unsaturated compound to form the ester.
4. The process according to claim 3 ,
wherein the ethylenically unsaturated compound is selected from:
ethene, propene, 1-butene, cis-2-butene, trans-2-butene, isobutene, 1,3-butadiene, 1-pentene, cis-2-pentene, trans-2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, hexene, tetramethylethylene (2,3-dimethyl-2-butene), heptene, 1-octene, 2-octene, di-n-butene or mixtures thereof.
5. The process according to claim 3 ,
wherein the compound in process step b), comprising Pd, is selected from:
PdCl 2 , PdBr 2 , Pd(acac) 2 , Pd(dba) 2 (dba=dibenzylideneacetone) or PdCl 2 (CH 3 CN) 2 .
6. The process according to claim 3 ,
wherein the alcohol in process step c) is selected from:
methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-propanol, tert-butanol, 3-pentanol, cyclohexanol, phenol or mixtures thereof.
7. The process according to claim 3 ,
wherein the reaction mixture is heated in process step e) to a temperature in the range from 80° C. to 160° C.
8. The process according to claim 3 ,
wherein CO is fed in in process step d) such that the reaction proceeds at a CO pressure in the range from 20 bar to 50 bar.
9. The process according to claim 3 ,
wherein the process comprises the additional process step f):
f) adding p-toluenesulfonic acid.
10. The process according to claim 3 ,
where R 1 and R 2 are the same radical.
11. The process according to claim 3 ,
where R 1 is t Bu.
12. The process according to claim 3 ,
where R 2 is t Bu.
13. The process according to claim 3 ,
wherein the compound has the structure (L1):
14. A process for preparing an ester comprising:
a) initially charging an ethylenically unsaturated olefin, thereby forming a reaction mixture;
b) adding a complex according to claim 1 ;
c) adding an alcohol;
d) feeding in CO;
e) heating the reaction mixture, with conversion of the ethylenically unsaturated compound to an ester.
15. The process according to claim 14 ,
wherein the ethylenically unsaturated compound is selected from:
ethene, propene, 1-butene, cis-2-butene, trans-2-butene, isobutene, 1,3-butadiene, 1-pentene, cis-2-pentene, trans-2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene, hexene, tetramethylethylene (2,3-dimethyl-2-butene), heptene, 1-octene, 2-octene, di-n-butene or mixtures thereof.
16. The process according to claim 14 ,
wherein the Pd in process step b), is sourced from:
PdCl 2 , PdBr 2 , Pd(acac) 2 , Pd(dba) 2 (dba=dibenzylideneacetone) or PdCl 2 (CH 3 CN) 2 .
17. The process according to claim 14 ,
wherein the alcohol in process step c) is selected from;
methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, 2-propanol, tert-butanol, 3-pentanol, cyclohexanol, phenol or mixtures thereof.
18. The process according to claim 14 ,
wherein the reaction mixture is heated in process step e) to a temperature in the range from 80° C. to 160° C.
19. The process according to claim 14 ,
wherein CO is fed in in process step d) such that the reaction proceeds at a CO pressure in the range from 20 bar to 50 bar.
20. The process according to claim 14 ,
wherein the process comprises the additional process step f):
f) adding p-toluenesulfonic acid.
21. The process according to claim 14 ,
where R 1 and R 2 are the same radical.
22. The process according to claim 14 ,
where R 1 is t Bu.
23. The process according to claim 14 ,
where R 2 is t Bu.
24. The process according to claim 14 ,
wherein the compound has the structure (L1):