Catalytic hydroformylation of olefins

In a process for the hydroformylation of linear or branched chain ethylenically unsaturated aliphatic olefins having from 2 to 20 carbon atoms to their corresponding aldehydes, in liquid phase, comprising reacting an olefin with carbon monoxide and hydrogen, the improvement which comprises conducting the hydroformylation reaction in the presence of an aqueous solution of at least one water-soluble phosphine having the following structural formula:

• ##STR8## in which:
• Ar.sub.1, Ar.sub.2 and Ar.sub.3, which may be identical or different, represent carbocyclic aryl groups having from 6 to 10 carbon atoms,
• Y.sub.1, Y.sub.2 and Y.sub.3, which may be identical or different, each represents a radical selected from the group consisting of linear or branched chain alkyl radicals having from 1 to 4 carbon atoms, alkoxy radicals having from 1 to 4 carbon atoms, halogen atoms, the --OH radical, the --C.tbd.N radical, the --NO.sub.2 radical, and the radical of the formula --NR.sub.1 R.sub.2, in which R.sub.1 and R.sub.2, which may be identical or different, represent a linear or branched chain alkyl radical having from 1 to 4 carbon atoms,
• M is an inorganic or organic cationic radical selected from the group consisting of the cations derived from the alkali metals, the alkaline earth metals, lead, zinc and copper, NH.sub.4.sup.+, and N(R.sub.3 R.sub.4 R.sub.5 R.sub.6).sup.+ wherein R.sub.3, R.sub.4, R.sub.5 and R.sub.6, which may be identical or different, each represents a linear or branched chain alkyl radical having from 1 to 4 carbon atoms,
• m.sub.1, m.sub.2 and m.sub.3 are identical or different integers between 0 and 5 and
• n.sub.1, n.sub.2 and n.sub.3 are identical or different integers between 0 and 3, at least one of the numbers n.sub.1, n.sub.2 or n.sub.3 being greater than or equal to 1,
• said aqueous solution of the sulfonated aryl phosphate additionally comprising a member selected from the group consisting of metallic rhodium and a rhodium containing compound.