Temperature lignocellulose alkaline

In summary, the chemicals to be laboratory-tested must be capable of reacting with lignocellulosic hydroxyls under neutral or mildly alkaline or acidic conditions at temperatures below 150°C. The chemical system should be simple and capable of swelling the structure to facilitate penetration. The complete molecule should react quickly with lignocellulosic components yielding stable chemical bonds, and the treated lignocellulosic must still possess the desirable properties of untreated lignocellulosics. 

The chemical activation of carbons is a complex solid-liquid reaction. The reaction takes place when the solid (carbon) reacts, at about 500°C, with a liquid (hydroxide), producing mainly H2, alkaline metal, and carbonate, if the heat treatment temperature is lower than 750°C. This reaction is a redox process in which carbon is oxidized to carbonate and hydroxide is rednced to alkali metal and hydrogen. This set of reaction products and the type of reactions taking place are not necessarily the same for all carbonaceous materials thus, for example, lignocellulosic... 

In comparison to other methods of lignocellulosic treatments, alkali treatments offer advantages of less severity of conditions. It can be operated at lower temperatures and pressures of up to even room conditions. However, long pre-treatment times and conversion of alkali into irrecoverable salts and the incorporation of salts into the lignocellulosic material still remain as challenges (Brodeur et al., 2011). The general equations for the alkaline treatment reactions are shown in scheme 3.2 where M represents sodium or calcium metals. 

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