Selective hydrogenation of alkynes to alkenes in the presence of a phosphorus compound and an organic sulphur compound

1 . A process for hydrogenating an alkyne selectively to an alkene which comprises subjecting the alkyne to hydrogenation conditions in the presence of a hydrogenation catalyst which is palladium supported on a carrier and in the presence of an additive mixture comprised of an additive AP and an additive AS, wherein

(a) the additive AP is an organic phosphorus compound having no sulphur atoms which is selected from the group consisting of triphenylphosphine, 1,2-bis(diphenylphosphino) ethane and 1,3-bis(diphenylphosphino) propane; and

(b) the additive AS which is 2,2′-(ethane-1,2-diylbis(sulfanediyl)) bis(ethan-1-ol) of the formula:

wherein

the alkyne comprises at least one carbon-carbon triple bond, and wherein

the at least carbon-carbon triple bond is selectively hydrogenated to a respective carbon-carbon double bond to form the alkene.

2 . The process according to claim 1 , wherein the additive AP and the additive AS are present in a molar ratio of the additive AP to the additive AS of 10:1-1:10.

3 . The process according to claim 1 , wherein the molar ratio of the additive AP to the additive AS is 5:1-1:5.

4 . The process according to claim 1 , wherein the molar ratio of the additive AP to the additive AS is 2:1-1:2.

5 . The process according to claim 1 , wherein the additive mixture and the hydrogenation catalyst are present in a weight ratio of the additive mixture to the hydrogenation catalyst of 0.01:1-100:1.

6 . The process according to claim 1 , wherein the weight ratio of the additive mixture to the hydrogenation catalyst is 0.1:1-10:1.

7 . The process according to claim 1 , wherein the weight ratio of the additive mixture to the hydrogenation catalyst is 0.2:1-3:1.

8 . The process according to claim 1 , wherein the carrier is an oxide or a carbonate.

9 . The process according to claim 8 , wherein the carrier is an oxide selected from the group consisting of silicon oxide, aluminum oxide, cerium oxide, titanium oxide and calcium carbonate.

10 . The process according to claim 1 , wherein the hydrogenation is performed in the absence of any organic solvents.

11 . The process according to claim 1 , wherein the carrier is carbon or an inorganic carrier.

12 . The process according to claim 1 , wherein the alkyne further comprises at least one chemical functional group, wherein the at least one further chemical functional group remains unchanged by the hydrogenation.

13 . The process according to claim 1 , wherein the alkyne is an alkynol of the formula (I):

and wherein the alkenol is an alkenol of the formula (II):

wherein either

(1) R 1 represents H, a methyl group or an ethyl group; and

R 2 represents a saturated or unsaturated linear, branched or cyclic hydrocarbyl group with 1 to 46 C atoms which optionally comprises at least one chemical functional group;

or

(2) R 1 and R 2 represent together an alkylene group forming a 5 to 7 membered ring;

with the proviso that R 1 has the same meaning in formulae (I) and (II) and that R 2 has the same meaning in formulae (I) and (II).

14 . The process according to claim 13 , wherein R 2 is selected from the group consisting of formula (R2-I), (R2-II), (R2-III), (R2-IV), (R2-V), (R2-VI) and (R2-VII),

wherein the dotted line represents the bond by which the substituent of formula (R2-I), (R2-II), (R2-III), (R2-IV), (R2-V), (R2-VI) or (R2-VII) is bound to the rest of the compound of formula (I) or formula (II);

and wherein any bond having dotted line ( ) represents independently from each other either a single carbon-carbon bond or a double carbon-carbon bond;

and wherein any wavy line represents independently from each other a carbon-carbon bond which when linked to the carbon-carbon double bond is either in the Z or in the E-configuration;

and wherein n represents 1, 2, 3, 4, 5 or 6.

15 . A composition comprising:

(i) an alkyne;

(ii) a hydrogenation catalyst which is palladium supported on a carrier; and

(iii) an additive mixture comprised of an additive AP and an additive AS, wherein

the additive AP which is an organic phosphorus compound having no sulphur atoms which is selected from the group consisting of triphenylphosphine, 1,2-bis(diphenylphosphino) ethane and 1,3-bis(diphenylphosphino) propane; and wherein

the additive AS is an organic sulphur compound having no phosphor atoms which is 2,2′-(ethane-1,2-diylbis(sulfanediyl)) bis(ethan-1-ol) of the formula: