Within the sustainable development of the chemical industry renewable resources are still in the focus for substitution of crude oil and other fossil raw materials. Following this way of sustainability, this thesis is addressed to the conversion of vegetable oils and its derivates by hydroformylation. The hydroformylation reactions of renewable raw materials were run in organic solvents as well as in ionic liquids as catalyst phase. During up to nine reaction cycles conversions of up to 96 % and yields of up to 89 % could be achieved. The products could be separated easily by decantation. This thesis could show, that the hydroformylation of oleic acid methyl ester and high oleic sunflower oil in ionic liquids as catalyst phase runs with multiple catalyst recycling with high conversion rates and yields.