2,3-Dialdehyde cellulose

Grafting of MMA onto dialdehyde cellulose proceeded more easily than onto mono-carbonyl cellulose... 

Rogovin, Yashunskaya and Shorygina [6] have studied the products of esterification of dialdehyde cellulose by means of nitric acid. The raw material, containing various quantities of aldehyde groups, was nitrated at 0°C with mixture composed of 48% HN03, 50% of H3P04 and 2% of P2Os. 

Following the periodate oxidation, the 2,3-dialdehyde celluloses were either reduced with potassium borohydride to form the dialcohol or oxidized with sodium chlorite to give dicarboxyl celluloses. The strength loss of the former products was kept lower than 27% and that of the latter 37%. 

Subjected to the same irradiation as the control samples, the breaking strength of the dialdehyde celluloses decreased almost linearly by 10-15% each week within the same oxidation level and no distinct accelerating effect of the introduced groups could be observed. After four weeks exposure, the intrinsic viscosity decreased by about 50-60% with respect to the nonexposed counterpart and by 70 to 80% with respect to the nonexposed unoxidized control. 

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]. 

Figure 2. Effect of carbonyl group content on the yield of copolymer, molecular weight, and apparent number of grafted chains in the pMMA-grafted dialdehyde-cellulose. Conditions cellulose, 0.3 g H2(), 10 mL MMA, 2 mL at 50°C for 1 h. Key (reaction tube) O, quartz d.Pyrex.

It is reported8711 that dialdehyde-cellulose incorporates nitromethane (and other nitroalkanes), to give polysaccharides containing 3-deoxy-3-nitroheptoseptanose residues. 

There are several methods to modify the chemical structure of cellulose hy oxidation. Periodate oxidation of cellulose suspended in water and N2O4 oxidation of cellulose suspended in chloroform are well-known conventional methods to convert cellulose to dialdehyde cellulose and C6-carhoxy cellulose, respectively. Generally, however, some side reactions including depolymerization are inevitable during these oxidations, and it is difficult, therefore, to achieve completely regioselective oxidation. 

An early use of periodate in an approach to a complex macromolecular problem consists of selective removal of cellulose from intimate association with lignin in wood. Repeated treatment of the fibrous matrix by oxidation followed by hydrolysis of the dialdehyde cellulose in water under reflux, affords lignin preparations referred to as periodate lignin on Purves lignin . 

T. J. Painter, Control of depolymerisation during the preparation of reduced dialdehyde cellulose, Carbohydr. Res., 179 (1988) 259-268. 

Finally, oxidation with TEMPO or periodate, respectively yielding 6-carboxy derivatives (glucuronans) and dialdehyde cellulose, should be mentioned. 6-Alde-hydo cellulose has been prepared via 6-azido-6-deoxy-cellulose and analyzed by gas-liquid chromatography (GLC)-MS of its deuterium-labeled reduced constituents. ... 

The reactivity of various proteins and enzymes with dialdehyde-cellulose has been investigated. ... 

In Sirvib s work [39], a water-soluble cationic cellulose derivative was synthesized by cationizing dialdehyde cellulose (DAC) produced by periodate oxidation of birch cellulose pulp by means of a reaction between aldehyde groups and cationic Girard s reagent T ((2-hydrazinyl-2-oxoethyl)-trimethylazanium chloride, GT) to produce cationic dialdehyde cellulose (CDAC). A schematic illustration of this cellulose oxidation and DAC cationization processes is shown in Fig. 3.3. 

The reaction of PH3 with dialdehyde cellulose in different mole ratios in an organic solvent was claimed to give a PH2-substituted, nonflammable cellulose derivative [161]. 

Kim UJ, Kuga S (2000) Reactive interaction of aromatic amines with dialdehyde cellulose gel. Cellulose 7 287-297... 

Cellulose-based natural fiber can be oxidized using oxidizing agent with acidic catalyst. Oxidation reactions applied to cellulose in fiber for chemical modifications [43]. Oxidation reactions occur on cellulose selectively at particular position. The reaction of sodium metaperiodate with cellulose in wood fiber in the presence of sulfuric acid catalyst at 120°C and 85 KPa pressure yielded the oxidized product. Sodium metaperiodate reacts with hydroxyl groups of cellulose and produce 2,3-dialdehyde cellulose which improved the physical and mechanical properties of polymer composites [44]. 

MODIFICATION OF PECULIARITIES OF MICROCRYSTALLINE CELLULOSE (MCC) AND ITS OXIDIZED LORM (DIALDEHYDE CELLULOSE DAC) GUANIDINE-CONTAINING MONOMERS AND POLYMERS OF VINYL AND DIALLYL SERIES... 

In this work for the first time have been studied modifieation peculiarities of microcrystalline eellulose (MCC) and its oxidized form (dialdehyde cellulose DAC) guanidine-containing monomers and polymers of vinyl and diallyl series [1-3]. The structure and some characteristics of used guanidine-containing modifiers are shown in Table 6.1. 

TABLE 6.1 Structure and some cellulose and dialdehyde cellulose characteristics of guanidine-containing modifiers of... 

FIGURE 6.3 SEM images dialdehyde cellulose (a) and complex of dialdehyde cellulose with N,N-diallylguanidme tiifluoroacetate (b). 

Figure 5 Reaction for conversion of cellulose to dialdehyde cellulose...

---