Selective hydrogenation of alkynols to alkenols in the presence of a phosphorus compound

Abstract

The present invention relates to a process of hydrogenating an alkynol selectively to an alkenol by hydrogen using a hydrogenation catalyst which is palladium supported on a carrier in the presence of an additive which is an organic phosphorus compound bearing either a phosphine or a phosphine oxide group and with the proviso that if the additive bears a phosphino group that the additive bears two or more phosphino groups.

1 . A process of hydrogenating an alkynol selectively to an alkenol by hydrogen using a hydrogenation catalyst which is palladium supported on a carrier;
 in the presence of an additive which is an organic phosphorus compound bearing either a phosphino or a phosphine oxide group; wherein in case the additive bears a phosphino group that the additive bears two or more phosphino groups.   
     
     
         2 . The process according to  claim 1 , wherein the alkynol is an alkynol which has a hydroxyl group attached to a carbon which is in alpha position to the carbon-carbon triple bond of the alkynol. 
     
     
         3 . The process according to  claim 1 , wherein the carbon-carbon triple bond is a terminal carbon-carbon triple bond. 
     
     
         4 . The process according to  claim 1  wherein the alkynol is an alkynol of the formula (I) 
       
         
           
           
               
               
           
         
         and the alkenol of the formula (II) 
       
       
         
           
           
               
               
           
         
         wherein 
         either 
         R 1  represents H or a methyl or ethyl group, preferably a methyl or ethyl group; and 
         R 2  represents a saturated or unsaturated linear or branched or cyclic hydrocarbyl group with 1 to 46 C atoms which optionally comprises at least one chemical functional group, particularly at least one hydroxyl group; 
         or 
         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). 
       
     
     
         5 . The process according to  claim 1  wherein R 1  is a methyl group. 
     
     
         6 . The process according to  claim 1  wherein R 2  is a methyl group. 
     
     
         7 . The process according to  claim 1  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), (R3-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, preferably a single 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, particularly 1 or 2 or 3, preferably 3 or 2, most preferably 2. 
       
     
     
         8 . The process according to  claim 1  wherein the additive has more than one phosphino groups of the formula (III) 
       
         
           
           
               
               
           
         
         wherein R is either an alkyl group or a cycloalkyl group or an aryl group, particularly a phenyl or a tolyl group and wherein the dotted line represents the bond by which the substituent of formula (III) is bound to the rest of the additive. 
       
     
     
         9 . The process according to  claim 1  wherein the organic phosphorus compound is selected from the group consisting of 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)-propane, 1,4-bis(diphenylphosphino)butane, 1,3-bis(diphenylphosphino)-2-(diphenyl-phosphino)methyl-2-methylpropane, 2,2′-bis(diphenylphosphino)-1,1′-binaphthalene and bis(2-diphenylphosphinoethyl)phenylphosphine; preferably selected from the group consisting of 1,2-bis(diphenylphosphino)ethane and 1,3-bis(diphenylphosphino)propane. 
     
     
         10 . The process according to  claim 1  wherein the hydrogenation is performed in the absence of any organic quaternary ammonium compounds. 
     
     
         11 . The process according to  claim 1  wherein the hydrogenation is performed in the absence of any organic solvents. 
     
     
         12 . The process according to  claim 1  wherein the carrier is carbon or an inorganic carrier, particularly an oxide or a carbonate, preferably silicon oxide, aluminum oxide or cerium oxide or titanium oxide or calcium carbonate. 
     
     
         13 . The process according to  claim 1  wherein the hydrogenation catalyst is in the form of a colloidal suspension. 
     
     
         14 . The process according to  claim 1  wherein the weight ratio of the additive to catalyst is in the range of 0.01:1-100:1, preferably of 0.1:1-10:1, and more preferably of 0.2:1-3:1. 
     
     
         15 . Composition comprising
 a compound of formula (I)   
       
         
           
           
               
               
           
         
       
       wherein 
       either 
       R 1  represents H or a methyl or ethyl group, preferably a methyl or ethyl group; and 
       R 2  represents a saturated or unsaturated linear or branched or cyclic hydrocarbyl group with 1 to 46 C atoms which optionally comprises at least one chemical functional group, particularly at least one hydroxyl group; 
       or 
       R 1  and R 2  represent together an alkylene group forming a 5 to 7 membered ring;
 a hydrogenation catalyst which is palladium supported on a carrier; and 
 at least one additive which is an organic phosphorus compound bearing either a phosphino or a phosphine oxide group; 
 wherein in case the additive bears a phosphino group that the additive bears two or more phosphino groups.