Lignin Calcium oxide

The use of the lignin fraction is much more cumbersome currently the best-known chemical of a real commercial importance is vanillin, which is obtained by oxidation of the black liquor. Another example is a product called spray-dried lignosulfonate (as sodium salt) obtained from the older, acidic sulfite pulping process. It is sold as a commercial product primarily as a concrete additive for enhanced strength. Since the cement industry is one of the big contributors of carbon dioxide emissions (due to the production of calcium oxide from calcium carbonate), the use of this renewable, wood-derived product not only is fossil-carbon neutral in itself but also reduces carbon dioxide emission due to the diminished need for cement in large infrastructures made of concrete. 

Other preliminary experiments on alkali lignin included oxidations by barium peroxide and alkali (5, 6), alkali fusion, and alkali fusions in the presence of calcium peroxide, sodium borate perhydrate, and monopersulfate compound. Ether extractives and water extractives were examined, but in all cases too many of the oxidation products obtained were new and unidentifiable, and it was impossible to evaluate the experiments adequately with the available techniques. Vanillic acid appeared to be the chief oxidation product under conditions which did not demethylate further or destroy the aromatic nature of the oxidation products. Some oxidation conditions yielded p-hydroxybenzyl moieties as products, and some gave no trace of these products whatever. More detailed studies of the ether-insoluble, water-soluble components of the several oxidation mixtures were postponed until adequate procedures were developed for analytical isolation and identification. 

A large number of patents describe various procedures for the mainly continuous hydrolysis and oxidation processes, as weU as for the purification steps requited to obtain high grade vanillin. Lignin is degraded either with sodium hydroxide or with calcium hydroxide solution and simultaneously... 

After the crude pulp is obtained from the alkaline sulfate process, it is bleached in stages with elemental chlorine, extracted with sodium hydroxide, and oxidized with calcium hypochlorite, chlorine dioxide, and hydrogen peroxide. This lightens it from a brown to a fight brown or even white (difficult) color. Chlorination of the aromatic rings of residual lignin is probably... 

Light orange chrome. See Lead chromate oxide Light petroleum hydrocarbons, odorless. See Petroleum hydrocarbons, odorless, light Light spar. See Calcium sulfate dihydrate Light yellow JB. See Diarylanilide yellow Lignin... 

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