The oxidative cleavage of the C=C-bond converts unsaturated fatty acid
s to carboxylic and dicarboxylic acids. The only method currently used
in oleochemistry is ozonolysis. The high energy consumption of ozonol
ysis makes a transition-metal catalyzed alternative with a cheaper sec
ondary oxidant attractive. Here we report new methods for ruthenium-,
rhenium- and tungsten-catalyzed oxidations with peracetic acid and hyd
rogen peroxide. Whereas the direct oxidative cleavage of internal C=C-
bonds still lacks selectivity, two-step reactions are feasible. The fi
rst possibility is to convert natural, internal unsaturated fatty acid
s to omega-unsaturated ones. These omega-unsaturated fatty acids can b
e cleaved by Ru/acac)(3)/CH3COOOH or Re2O7/H2O2 With yields up to 80%.
In the second two-step procedure the fatty acid first is hydroxylated
and the diol is cleaved; the overall yield for this method is 80%, to
o.