Carboxyl radicals functional group comparability

The alkyl groups of two identical carboxylic acids can be coupled to symmetrical dimers in the presence of a fair number of functional groups (equation 1). Since free radicals are the reactive intermediates, polar substituents need not be protected. This saves the steps for protection and deprotection that are necessary in such cases when electrophilic or nucleophilic C—C bond-forming reactions are involved. Furthermore, carboxylic acids are available in a wide variety from natural or petrochemical sources, or can be readily prepared from a large variety of precursors. Compared to chemicd methods for the construction of symmetrical compounds, such as nucleophilic substitution or addition, decomposition of azo compounds or of diacyl peroxides, these advantages make the Kolbe electrolysis the method of choice for the synthesis of symmetrical target molecules. No other chemical method is available that allows the decarboxylative dimerization of carboxylic acids. 

PMMA/hydroxyapatite bone cement. Both nanostructures were found to capture the radicals produced during the cement polymerization process, thereby hampering their normal course and affecting the mechanical properties of the nanocomposites, especially the one-dimensional nanoform [145]. Recently, we have compared both 1D and 2D carbon nanostructures and the effect of functionalization on the thermomechanical properties. As seen in Figure 10.13, the nanofillers containing carboxylic groups provided the best mechanical response at 1 wt% loading. Additionally, the 2D carbon structures provided better reinforcement in the electrospun fibers when compared to the ID carbon nanomaterials [116,158]. 

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