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The nitration and fractionation of whole wood

University of British Columbia

In an attempt to develop a method by which the chemical components of whole wood samples could be separated on a quantitative basis, the reactions of gaseous dinitrogen pentoxide with model substances and with acetone-extracted wood have been studied. The crystalline compounds D-mannitol, benzoic acid and D,L-tartaric acid were smoothly nitrated by exposure to an excess of the pentoxide at 0 ± 2° C. and the crystalline products D-mannitol hexanitrate, D,L-tartaric acid dinitrate and m-nitrobenzoic acid were recovered directly in quantitative yield. Good yields of the crystalline although somewhat less pure nitrates of D,L-mandelic acid, β-methyl-D-glucopyranoside and D-sorbitol were obtained in similar nitrations. D-Mannose, D-fructose, dulcitol, sucrose, maltose, lactose, cellobiose, vanillic acid, salicylic acid and vanillin gave poor yields of syrupy nitrated products. A beechwood xylan and holocellulose and lignin of western red cedar, isolated by conventional technics, were nitrated by the gaseous pentoxide method in yields and nitrogen contents comparable to those reported for other nitration methods. The xylan and holocellulose nitrates were incompletely soluble in acetone and the solubility of the nitrated lignin varied with the time of nitration. Optimum conditions were established for the nitration of acetone-extracted western red cedar heartwood. The weight ratio of nitrated wood : wood was closely reproducible and exceeded previously reported values; total nitrogen and ester nitrogen contents of the nitrated wood were reproducible within, the experimental error of the determinations. The nitration reaction was not entirely quantitative since an average of 2.3% methoxyl was lost from the wood and the weight increase calculated from the total nitrogen content was, on the average, 3% lower than the observed value. Successive extraction with anhydrous acetone and methanol applied alternately, dissolved up to thirty-five percent of the nitro-wood and indicated that the nitration-solvent extraction technic should have value as a tool in the study of wood chemistry.

Text

2012-01-31

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http://hdl.handle.net/2429/40390

Chemistry

University of British Columbia

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