Cannizzaro Cellulose

Determination of dialdehydes in periodate cellulose can also be based on consumption of hydroxyl ions by the Cannizzaro reaction [92], The -elimination reaction of 2,3-dialdehyde celluloses in combination with DP-determination is proposed as a means to roughly determine the extent of oxidation [93]. 

The only other noticeable effect of variation of the experimental parameters shown (Table I) is a negative effect of high alkali concentration on oil yield, when the sodium carbonate concentration is raised to 2.37 N (12.6%) at 270-343 C. This is counter to Elliott and Giacoletto s results (10). The effect of alkali on cellulose chain peeling and cleavage was found to be directly proportional to alkali concentration at lower temperatures (185 C) (47). Since high alkali concentrations favor the hydride- transfer mediated Cannizzaro reaction to yield acid salts and alcohols from aldehydes and some ketones, we suggest that perhaps the lower oil yield may be due to removal of carbonyl intermediates from the reaction. 

Step 6 is the final step in the cellulose-to-lactic acid cascade, involving the isomerization of the 2-keto-hemi-acetal (here pyruvic aldehyde hydrate) into a 2-hydroxy-carboxyhc acid. This reaction is known to proceed in basic media following a Cannizzaro reaction with 1,2-hydride shift [111], Under mild conditions, Lewis acids are able to catalyze this vital step, which can also be seen as an Meerwein-Ponndorf-Verley reduction reaction mechanism. The 1,2-hydride shift has been demonstrated with deuterium labeled solvents [110, 112], Attack of the solvent molecule (water or alcohol) on pymvic aldehyde (step 5) and the hydride shift (step 6) might occur in a concerted mechanism, but the presence of the hemiacetal in ethanol has been demonstrated for pyruvic aldehyde with chromatography by Li et al. [113] andfor4-methoxyethylglyoxal with in situ CNMRby Dusselier et al. (see Sect. 7) [114]. 

M.L. Rollins, AM. Cannizzaro, and W.R. Goynes. In Instrumental Analysis of Cotton Cellulose and Modified Cotton Cellulose, R.T. O Connor (ed.), Marcel Dekker, New York, 1972. 

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