Valeraldehyde and process for its preparation

Abstract

Bidentate phosphine ligands of the formula wherein the substituents are as defined in the specification and a process for preparing linear aldehydes by hydroformylating internal olefins using such phosphine ligands.

What we claim is:  
     
         1 . A bidentate phosphine ligand of the formula  
       
         
           
           
               
               
           
         
       
       wherein R1, R2, R3 and R4 are independently selected from the group consisting of hydrogen, fluorine, alkyl of 1 to 8 carbon atoms, alkoxy of 1 to 8 carbon atoms, acyloxy of an organic carboxylic acid of 1 to 8 carbon atoms, aryl of 6 to 18 carbon atoms, aryloxy of 6 to 18 carbon atoms, —CN, —CF 3 , —CHO, —SO 3 H, —SO 3 M, —SO 3 R, —SOR, —NH 2 , —NH-alkyl of 1 to 8 carbon atoms, —N-alkyl 2  of 1 to 8 carbon atoms, —NHCO-alkyl, —N-(alkyl)-(CO-(alkyl) where the alkyl have 1 to 4 carbon atoms, —COO-alkyl of 1 to 8 carbon atoms, —CONH 2 , —CO-alkyl of 1 to 8 carbon atoms, —NHCOH, —NHCOO-alkyl of 1 to 4 carbon atoms, —CO-aryl of 1 to 8 carbon atoms, —COO-aryl of 1 to 8 carbon atoms, —CHCH—CO 2 -alkyl of 1 to 8 carbon atoms, —PO-(-aryl) 2  of 1 to 8 carbon atoms, —PO-(alkyl 2 ) of 1 to 4 carbon atoms; M is a cation selected from the group consisting of alkali metal ions, alkaline earth metal ions, —NR 2 H 2 , —NR 3 H, —NRH 3 , —NR 4 , —NH 4 , —PR 2 H 2 , —PR 3 H, —PRH 3 , —PR 4  and —PH 4 ; or R1, R2, R3 and R4, with one another, together form at least one aliphatic or aromatic ring of 5 to 20 carbon atoms; E is a bridge linking the two phosphorus atoms, where the number of atoms situated between the two phosphorus atoms is 2 and 6, selected from the group consisting of C, N, Si, S, 0, P, Fe and As; X is selected from the group consisting of —O—, —S—, —Si(R a ) 2 —, —Si(OR a ) 2 —, —N(C(O)R a )—, —N(R b )—, —C(R c )(R c ), —C(O)—, —N(SiR d )—, —P(R d )—, P(O)(R d )—, —C═C(R c )(R c )— and —P(OR d )— wherein 
 R a  is alkyl of 1 to 8 carbon atoms,  
 R b  is aryl of 6 to 18 carbon atoms,  
 R c  is selected from the group consisting of hydrogen, alkyl of 1 to 8 carbon atoms, aryl of 6 to 18 carbon atoms, alkoxy of 1 to 8 carbon atoms, aryloxy of 6 to 18 carbon atoms, R a (O)— and R b (o); and  
 R d  is one of R a  or R b .  
 
     
     
         2 . The ligand of  claim 1  wherein E is selected from the group consisting of  
       
         
           
           
               
               
           
         
       
       wherein X is selected from the group consisting of —O—, —S—, —Si(R a ) 2 —, —Si(OR a ) 2 —, —N(C(O)R a )—, —N(R b )—, —C(R c )(R c )—, —C(O)—, —N(SiR d )—, —P(R d )—, —P(O)(R d )—, —C═C(R c )(R c )— and —P(OR d )—, 
 R a  is alkyl of 1 to 8 carbon atoms  
 R b  is aryl of 6 to 18 carbon atoms  
 R c  is selected from the group consisting of hydrogen, alkyl of 1 to 8 carbon atoms, aryl of 6 to 18 carbon atoms, alkoxy of 1 to 8 carbon atoms, aryloxy of 6 to 18 carbon atoms, R a (O)— or R b (O)—;  
 and Rd is one of R a  or R b ;  
 Y is oxygen or sulfur; and  
 R5s are individually aryl of 6 to 18 carbon-atoms or alkyl of 1 to 8 carbon atoms.  
 
     
     
         3 . The ligand of  claim 1  wherein E is selected from the group consisting of  
       
         
           
           
               
               
           
         
       
       wherein R 6  is alkyl of 1 to 6 carbon atoms or aryl of 6 to 18 carbon atoms, Z is oxygen or nitrogen and n is an integer from 2 to 6.  
     
     
         4 . A process for the preparation of a linear aldehyde comprising hydroformylating an internal olefin of 4 to 12 carbon atoms with carbon monoxide and hydrogen in the presence of a bidentate phosphine ligand of  claim 1 .  
     
     
         5 . The process of  claim 4  wherein E is selected from the group consisting of  
       
         
           
           
               
               
           
         
       
       wherein X is selected from the group consisting of —O—, —S—, —Si(R a ) 2 —, —Si(OR a ) 2 —, —N(C(O)R b )—, —N(R b )—, —C(R c )(R c )—, —C(O)—, —N(SiR d )—, —P(R d )—, —P(O)(R d )—, —C═C(R c )(R c )— and —P(OR d )—, 
 R a  is alkyl of 1 to 8 carbon atoms  
 R b  is aryl of 6 to 18 carbon atoms  
 R c  is selected from the group consisting of hydrogen, alkyl of 1 to 8 carbon atoms, aryl of 6 to 18 carbon atoms, alkoxy of 1 to 8 carbon atoms, aryloxy of 6 to 18 carbon atoms, R a (O)— or R b (O)—; and R d  is one of R a  or R b ;  
 Y is oxygen or sulfur; and  
 R5s are individually aryl of 6 to 18 carbon atoms or alkyl of 1 to 8 carbon atoms.  
 
     
     
         6 . The process of  claim 4  wherein E is selected from the group consisting of  
       
         
           
           
               
               
           
         
       
       wherein R 6  is alkyl of 1 to 6 carbon atoms or aryl of 6 to 18 carbon atoms, Z is oxygen or nitrogen and n is an integer from 2 to 6.  
     
     
         7 . The process of  claim 4  wherein the reaction is carried out in the presence of 1 to 1000 μm of rhodium based on the total reaction mixture.  
     
     
         8 . The process of  claim 7  wherein rhodium is present at 10 to 250 ppm.  
     
     
         9 . The process of  claim 7  wherein the ratio of rhodium to ligand is 1:1 to 1:100.  
     
     
         10 . The process of  claim 7  wherein the ratio of rhodium to ligand is 1:1 to 1:20.  
     
     
         11 . The process of  claim 4  wherein the hydroformylation is effected at 10 to 180° C.  
     
     
         12 . The process of  claim 4  wherein the hydroformylation is effected at 80 to 140° C.  
     
     
         13 . The process of  claim 4  wherein the reaction is effected at a pressure of 0.1 to 200 bar.  
     
     
         14 . The process of  claim 4  wherein the hydroformylation is effected in the presence of a solvent selected from the group consisting of ether, carbon dioxide, fluorinated hydrocarbons, toluene and benzene.  
     
     
         15 . The process of  claim 4  wherein the hydroformylation is effected in a polar aprotic solvent selected from the group consisting of dimethylformamide, dimethylacetamide and N-methylpyrrolidone.  
     
     
         16 . The process of  claim 4  wherein the hydroformylation is effected in the presence of an oligomeric aldehyde.  
     
     
         17 . The process of  claim 16  wherein the oligomeric aldehyde is the trimer of the aldehyde to be formed.  
     
     
         18 . The process of  claim 11  wherein the hydroformylation is effected in a two phase with water.  
     
     
         19 . The process of  claim 4  wherein the ratio of carbon monoxide to hydrogen is 1:10 to 10:1.  
     
     
         20 . The process of  claim 4  wherein the ratio of carbon monoxide to hydrogen is 1:2 to 2:1.