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Kraft lignin from black liquor, which is produced in much higher amounts, may be processed into sulfonated lignin. The lignin is first precipitated by acidifying the liquor with CO 2 then washed (other methods for isolation exist). Reaction with sodium sulfite or sodium bisulfite and an aldehyde under a basic environment completes sulfonation.
Lignin was first mentioned in 1813 by the Swiss botanist A. P. de Candolle, who described it as a fibrous, tasteless material, insoluble in water and alcohol but soluble in weak alkaline solutions, and which can be precipitated from solution using acid. [3] He named the substance "lignine", which is derived from the Latin word lignum, [4 ...
The lignin is converted to lignosulfonates, which are soluble and can be separated from the cellulose fibers. For the production of cellulose, the sulfite process competes with the Kraft process which produces stronger fibers and is less environmentally costly. idealized scheme for lignin depolymerization by the Sulfite process.
Sodium lignosulfonate (lignosulfonic acid, sodium salt) is used in the food industry as a de-foaming agent for paper production and in adhesives for items that come in contact with food.
The term "lignin characterization" (or "lignin analysis") refers to a group of activities within lignin research aiming at describing the characteristics of a lignin by determination of its most important properties. [1] Most often, this term is used to describe the characterization of technical lignins by means of chemical or thermo-chemical ...
The black liquor is an aqueous suspension of lignin residues, hemicellulose, and the inorganic chemicals used in the process. The black liquor comprises 15% solids by weight of which two thirds are organic chemicals and the remainder are inorganic. [3] Normally the organics in black liquor are 40-45% soaps, [4] 35-45% lignin and 10-15% other ...
Chemical structure of lignin, which makes up about 25% of wood dry matter and is responsible for many of its properties. The chemical composition of wood varies from species to species, but is approximately 50% carbon, 42% oxygen, 6% hydrogen, 1% nitrogen, and 1% other elements (mainly calcium , potassium , sodium , magnesium , iron , and ...
White liquor consists mainly of sodium hydroxide and sodium sulfide in water and is the active component in Kraft pulping. [1] White liquor also contains minor amounts of sodium carbonate, sodium sulfate, sodium thiosulfate, sodium chloride, calcium carbonate and other accumulated salts and non-process elements.