Hydrogenation of Aliphatic Carboxylic Acids

Aliphatic aldehydes are also important intermediates for fine chemical manufacture. The Cr -modified catalyst, however, is not suitable for the preparation of these, because of its low selectivity [17]. 

Several commercially available Cr203 catalysts have been tested, affording quite different results for activity and selectivity (Table 4). Impurities in Cr203, especially alkali metals and alkaline earth metals, have a strong influence on catalytic performance. These contaminant impurities in Cr203 result in a drastic decrease in activity and selectivity, as has been reported elsewhere [17]. Selectivity is reduced mainly because of ketone formation. 

Catalyst Temperature rc) Conversion of acid (%) Selectivity (%) Total-UDEH Ketone 10-UDEH/ Total-UDEH 

4 Application of Cf203 Catalysts to Different Aliphatic Carboxylic Acids 

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It is worth mentioning that cyclic acetal-type saccharide-based surfactants are promising not only with respect to their environmental properties but also as concerns their synthesis. Recently, the Mitsubishi Chemical Corporation elaborated and commercialized a process of direct hydrogenation of aliphatic carboxylic acids to the corresponding aldehydes [181,182]. This process allows long-chain aliphatic aldehydes to be obtained from natural fats and oils, and, as a consequence, to produce cyclic acetal-type saccharide surfactants entirely from renewable feedstock. 

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