Preparation of zerovalent phosphine substituted rhodium compounds and their use in the selective carbonylation of olefins

A process for the production of normal aldehydes which comprises the step of contacting an alpha olefinic hydrocarbon having up to 20 carbon atoms at a temperature ranging from 50.degree. to 175.degree.C. and a pressure ranging from 10 to 1000 psi with carbon monoxide and hydrogen in the presence of a catalyst wherein the amount of catalyst ranges from 10.sup..sup.-6 to 10.sup..sup.-1 mols of rhodium per mol of alpha olefinic hydrocarbon and wherein said catalyst composition is characterized as one of the following zero-valent rhodium complexes:

• [(L)(L')Rh.degree]sub.2 , [L.sub.3 Rh.degree]sub.2 , [L.sub.2 'Rh.degree]sub.2 , [L"Rh.degree]sub.2
• where L is a monodentate phosphine ligand, L' is a bidentate phosphine ligand and L" is a tri or quadra-dentate phosphine ligand, wherein L, L' and L" is the same or different and each is one selected from the group consisting of:
• 1. R.sub.3 P, R.sub.2 R'P , (RR'R")P
• 2. r.sub.2 p(cr.sub.2 ').sub.x P R.sub.2 ' ##EQU6##
• 5. R"P[(CR.sub.2 ').sub.x PR.sub.2 "].sub.2
• 6. p[(cr.sub.2 ').sub.x PR.sub.2 ].sub.3
• wherein R, R' and R" can be the same or different and each is selected from the group consisting of hydrogen, F, Cl, Br and I, C.sub.1 to C.sub.4 alkyl, to C.sub.4 alkoxy, C.sub.3 to C.sub.8 cycloalkyl, C.sub.3 to C.sub.8 cycloalkyl, phenyl, phenyl substituted with F, Cl, Br and I, phenyl substituted with C.sub.1 to C.sub.4 alkyl, phenyl substituted with C.sub.3 to C.sub.8 cycloalkyl, phenyl substituted with C.sub.1 to C.sub.4 alkoxy, oxyphenyl, oxyphenyl substituted with C.sub.1 to 132 20C.sub.4 alkyl, oxyphenyl substituted with C.sub.3 to C.sub.8 cycloalkyl, oxyphenyl substituted with F, Cl, Br and I, oxyphenyl substituted with C.sub.1 to C.sub.8 cycloalkoxy;
• can be the same or different and each is selected from the and x is an integer ranging from 1 to 5.