A REVIEW OF INFRARED-SPECTRA FROM WOOD AND WOOD COMPONENTS FOLLOWING TREATMENT WITH LIQUID-AMMONIA AND SOLVATED ELECTRONS IN LIQUID-AMMONIA

The chemical changes that occur in wood and wood components (cellulose , holocellulose and lignin) following treatment with liquid ammonia an d solvated electrons (e(s)(-)) in liquid ammonia have been investigate d using FT-IR spectroscopy. When ammonia penetrates into a wood struct ure, all carboxylate groups will react with ammonia to form ammonium s alts, aldehydic and ketonic groups will follow a similar reaction to p roduce imines, and ester groups will react to form amides. After treat ment with (e(s)(-)) in liquid ammonia, wood samples show diminished ab sorption around 1513 cm(-1), a position corresponding to aromatic grou ps, and diminished absorption peaks associated with aldehydic, ketonic , and ester groups. The overall changes in the IR spectra of cellulose in liquid ammonia and (e(s)(-)) in liquid ammonia are not dramatic. T he IR spectra of the isolated holocellulose after treatment with (e(s) (-)) in liquid ammonia have intensities and band shape similar to thos e of cellulose. The isolated lignin behaves in a manner similar to woo d, in that the liquid ammonia causes some decrease in the intensities of absorptions associated with C-O and C=O bands, and increase in stre ngth of the amide functional group at 1600 cm(-1). The resulting extra cts of wood, following treatment with (e(s)(-)) in liquid ammonia, app ear to loose their ''aromaticity''. Because wood has long been used, a nd still is used extensively as an important constructional material, the changes in mechanical characteristics caused by the action of vari ous reducing agents appears to have been an important area of scientif ic interest. The following review focuses on the chemical changes in t he functional groups of the surface moieties of wood when treated with a reducing agent, such as (e(s)(-) + NH3liq), using infrared spectros copy.