Cellulose reaction with hydrogen peroxide

A method of grafting vinyl monomers to substrates of cellulose xanthate was invented by Faessinger and Conte-. The initiation is a reaction of ferrated (12) or acidic (13) cellulose xanthate with hydrogen peroxide according to the following scheme (HO-OH and Fe + give HO- radicals) ... 

Figure 6.10 Xanthation of cellulose followed by reaction with hydrogen peroxide to generate a radical.

The xanthate method [62] is considered as one of the most promising methods for industrial chemical modification. The principal involved in the xanthate method of grafting is that cellulosic xanthate either ferrated or in acidic conditions reacts with hydrogen peroxide to produce macroradicals. The following reaction mechanism has been proposed ... 

Oxidative bleaching of wool is invariably carried out with hydrogen peroxide. The active species involved is likely to be the same as on cellulosic substrates but specific reactions with wool amino acid residues must be considered. The primary reaction is oxidation of cystine disulphide bonds leading to the formation of cysteic acid residues (Scheme 10.41). The rupture of disulphide crosslinks, with attendant increase in urea-bisulphite and alkali solubility values, adversely affects fibre properties. As the severity of bleaching conditions increases, the urea-bisulphite solubility remains little changed but the relationships between alkali solubility and cysteic acid (Figure 10.36) and between cystine and cysteic acid (Figure... 

The effects of photosensitizers on the formation of free radicals on u.v.-irradiation of cellulose at 77 K have been investigated. Samples of cellulose treated with benzoyl peroxide, hydrogen peroxide, benzophenone, riboflavin, Cr + ions, or Ni + ions exhibited single-line e.s.r. spectra, whereas those treated with Pb + or Fe + ions exhibited three- and five-line e.s.r. spectra, respectively. Studies of the decay of radicals in photo-irradiated cellulose at low temperatures indicated that at least six types of radical are formed. Changes in the radicals with the reaction conditions were carefully examined. 

It is assumed by some authors that hydroxyl radicals formed from hydrogen peroxide and ferrous ions react with cellulose in a similar manner to ethanol in reaction (XI) and that radical formation caused by such hydrogen abstraction leads to active sites from which graft polymerization can start ... 

The modification of the properties of cotton cellulosic textile products, through free radical-initiated graft copolymerization reactions with vinyl monomers, has been investigated at the Southern Laboratory for a number of years (6, 9). In this chapter, we summarize the basic mechanisms and principles involved in free radical reactions of cellulose, initiated by high energy radiation, ceric ion in acidic solution, and aqueous solutions of ferrous ion and hydrogen peroxide. Some of the properties of fibrous cotton cellulose graft copolymers are also presented. 

To produce radicals the cellulose substrate can be saturated with potassium persulfate. Another method includes impregnation of cellulose with ferrous salts followed by treatment with a monomer solution in the presence of hydrogen peroxide. Hydroxyl radicals are produced in this system according to the following reaction ... 

---