Catalytic efficiency of zerovalent iron compounds as paint driers compared with conventional substances : the use of ferrocene and other iron compounds as driers in autoxidative paint systems at ambient and elevated temperatures
Novel paint driers based on iron co-ordination complexes were investigated for use as stoving finishes in oil-based coatings. Cis 9, cis 12-octadecadienoic acid was employed as a model vehicle because of its high drying capacity. Iron compounds generally have low catalytic efficiency at low temperatures which however improve with rises in temperature. The catalytic efficiency of some iron compounds was compared with those of some conventional driers at room temperature; 60 C, 80 C and 1200 C. To make the results comparative, equal weights of drier (0.05%) metal were employed in one series of experiments. In another series, a much higher concentration (0.25%) metal based on the weight of 9,12-octadecadienoic acid was employed. Equal weights of drier combination(s) and variable drier weights were examined to determine synergism or antagonism in the autoxidative systems. Maximum oxygen absorption, changes in iodine and peroxide values were monitored to determine a comparative catalytic performance of the driers at the reaction temperatures used. The reactivity of iron co-ordination complexes was found to be influenced by the organic compound with which the iron is chelated. Zerovalent iron complexes can be employed as high temperature driers. For convenience some common names have been used for major chemicals of importance in this work, e. g., Linoleic acid; cis 9, cis 12-octadecadienoic acid. Ferrocene; dicyclopentadienyl iron.