Motivated by the production of compounds of good industrial value, pyrolysis of fir wood catalyzed by alkaline compounds (NaOH, KOH, Na 2 CO 3 , K 2 CO 3 , KC 2 H 3 O 2 , and NaCl) has been investigated. Catalysts have been impregnated in wood (preliminarily extracted with water) by means of aqueous solutions resulting in concentrations of the K or Na ion in wood of about 0.37-0.41%. Pyrolysis experiments have been done with a fixed-bed reactor preheated at 800 K.The decomposition process is anticipated at lower temperatures with conversion times from 2.5 (NaOH) to 1.7 (NaCl) times shorter. Formation of char, carbon dioxide, and water is favored with total yields between 70 and 61% versus 48% of extracted wood (dry sample mass basis). The yields of carbon monoxide are increased approximately from 4% to 6% while the yields of organic compounds are lowered to 19-29% (versus 43%) with the disappearance of sugar compounds and a strong diminution in other typical products of uncatalyzed wood pyrolysis but hydroxypropanone. However, sodium and potassium hydroxides increase the yields of some minor carbohydrate compounds (1-hydroxy-2butanone, 2-methyl-2-cyclopentenone, 3-ethyl-2-hydroxy-2-cyclopentenone, and 3-methyl-2-cyclopentenone) by factors of 4-6 (yields of about 0.8-0.12%). The yields of total phenols are also increased. In particular, NaOH is slightly more effective for the production of guaiacol, cresols, and 4-ethylguaicol (factors of increase between 3 and 4 with yields of 0.3-1.2%), whereas KOH is slightly better for the production of phenol, cis-isoeugenol and transisoeugenol (factor of increase of 2-6 with yields between 0.7 and 0.2%). Finally, the production of furfuryl alcohol can be augmented up to factors of about 15 by potassium hydroxide or carbonate (yields up to 0.6%).

The catalytic effects of diammonium phosphate on wood pyrolysis are investigated for applications in specialty chemical production and fire retardance. For a fixed-bed reactor operated at a temperature of 800 K, over a range of salt concentrations of 0-20%, the yields of char and water continuously increase (from 22 and 20%, respectively, to 45%), at the expense mainly of organic liquid products (from 43 to 6%) with only a small reduction in the yields of gases (percentages on a dry wood basis). As for the organic products, the yields of phenols, guaiacols, hydroxyacetaldehyde, hydroxypropanone, and some other minor carbohydrates rapidly attain low values. Major variations are undergone by levoglucosan only for mild treatments of wood, whereas levoglucosenone and 2-furaldehyde remain at the maximum values over a range of salt concentrations of roughly 2-5%. Diminution in the yields of acetic acid is generally slow. The same qualitative trends are preserved for a reactor temperature of 650 K. The ratio of the noncombustible to the combustible volatile products increases from 0.5 up to 5.5 already for a salt concentration of about 10%, thus confirming the fire-retardant action of diammonium phosphate in wood. Conversion times and global devolatilization rates are significantly affected by the modifications in the process energetics caused by salt addition.

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Motivated by the production of fine chemicals and the improvement of flame retardance properties, experiments have been performed with a fixed-bed reactor to investigate the catalytic action exerted by zinc chloride on fir wood pyrolysis (catalyst concentrations between 0 and 16% on a dry wood basis and heating temperatures between 650 and 900 K). It has been observed that this Lewis acid acts as a dehydrating and cross-linking agent promoting the formation of char and water with total yields up to about 73%. As a consequence, the majority of organic condensable products generated from uncatalyzed pyrolysis of wood (hydroxyacetaldehyde, hydroxypropanone, levoglucosan, and other minor carbohydrates, phenols, and guaiacols) is rapidly reduced to low values. However, zinc chloride is a particularly effective catalyst (concentrations of 1–6% and temperatures of 700–800 K) to maximize the yields of levoglucosenone, acetylfuran, 5-methyl-2-furaldehyde, and, especially, 2-furaldehyde which is augmented by a factor of 5. Zinc chloride also introduces good fire retardance properties of wood as testified, in addition to the enhanced formation of char and water, by the halving of the release rate of flammable volatile species and the five-factor increment in the ratio of noncombustible to combustible volatile product yields.

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