The UV spectra of cellulose and some model compounds

Abstract

SynopsisComparison of the reflectance spectrum of cellulose with that of myoinositol, cycloheptaamylose, and other model compounds indicates that the acetal linkage does not contribute significantly to the absorption peak at 260 nm. The spectra of photolyzed and photo-oxidized cellulose suggest that ketonic carbonyl groups are a more likely cause of t h s peak. Photolysis of cellulose and amylose under vacuum with 253.7 nm light increases the concentration of ketonic carbonyls and thus promotes yellowing. Photo-oxidation with 253.7-nm light bleaches both carbohydrates owing to the formation of carboxyl groups. Other investigators had previously reported that this last reaction yellows cellulose, but it appears that this was an effect caused by the 184.9-nm component in the light of the lamp used. Comparison of the spectra of thermally and photolytically yellowed cellulose indicates that the end products of the two degradations are quite different.

Experimental and Theoretical Study of the Yellowing of Ancient Paper

“…Spectra for unaged samples are not reported because they do not show any absorption below 5 eV. All absorbance spectra of modern samples artificially aged consist of a broad peak around 4.8 eV (260 nm) already attributed to the development of carbonyl groups in glucopyranose units [10]. For samples aged in C and V conditions an additional peak at 4.2 eV (295 nm) appears.…”

“…The absorption peak at 4.8 eV has been attributed to the development of carbonyl groups through the comparison of the spectra of similar compounds [10]. On the other hand, pure cellulose shows no absorption bands in the ultraviolet-visible (UV-Vis) region up to around 6 eV (200 nm) [7].…”

Superficial and Shroud-like coloration of linen by short laser pulses in the vacuum ultraviolet

“…3 and 4. This additional mechanism could be promoted by the absorption band below 0.2 μm of alkene groups (─C═C─) [41] typical of degraded cellulose and of organic impurities of the primary cell wall of linen fibers. The VUV absorption of these groups may trigger a reaction chain that leads to photo-oxidation (aging) and to new alkenes and carbonyl groups.…”

“…In particular, the VUV radiation at 0.193 μm is absorbed by alkene groups in degraded cellulose, whose number increases with F T , thus inducing a photolysis of the cellulose, which promotes the formation of chromophores; see Fig. 14. These chromophores determine the yellow coloration of the fibers [8,12,[39][40][41].…”

Photoactive polysaccharides

“…The chemical nature of the chromophores in cellulose has been studied utilizing reference model compounds since the 1960s (Beelik & Hamilton, 1961;Bos, 1972). The weak absorption bands in the 210-320 nm UV range were assigned to carbonyl and acetal groups as well as various impurities such as trace amounts of transition metal ions (Atalla & Nagel, 1972).…”