Lignin dispersing agents

Dispersal of lignin as a colloid is a close relative of true solution as a means of lignin removal. Dispersing agents include alkalis. Effective dispersion may involve molecular weight reduction as a necessary condition. 

The dispersion agents used are primarily lignin sulfonates (sulfite cellulose liquors) condensation products of naphthalene, sulfuric acid, and formaldehyde condensation products of m - and o-cresol, formaldehyde, and 2-hydroxynaphtha-lene-6-sulfonic acid [93-01-6] or mixtures of these products [46], Literature on dispersing agents is relatively scarce [47-49],... 

Dispersing agents (sulfonated lignins) Carriers/Accelerants (benzene and... 

Lignotech Group Swtzerland, Finland, Spain, South Africa, China Kraft lignin (Eucalin) Additives—ceramics, concrete and gypsum Dispersing agents—agro chemicals, battery expanders, dyestuffs, water treatments Binders—carbon black, fertilizers, limestone, mud dispersants Plant nutrition—humates and micronutrients... 

The flow properties of the slurry may be improved by adding suitable dispersing agents, such as sulforrated rraphthalene formaldehyde condensate (SNFC), sulfonated melamine formaldehyde condensate (SMFC), or lignin-based dispersants. 

Wood consists of 40-50% cellulose, 20-30% hemi-celluloses, 21-23% lignin, 0.2-0.5% protein, and 1-5% mineral matter, which is left behind as ash when the wood is burned. Besides its straightforward use as timber, much wood is pulped for use in papermaking. Lignin is extracted in the process by either sulfonation or chlorination. Sulfonation produces lignosulfonates, which are widely used as dispersing agents, for example as chemical admixtures for concrete to disperse the cement particles (see the section on Cement and Concrete Admixtures, below). 

Disperse dyes are materials that have very low water solubility (typically 10 mole fraction). Disperse dyes are supplied as finely divided powders containing dispersing agents (e.g., naphthalene sulfonic acid and lignin sulfonate), which keep the particles suspended in the dyebath. They are applied to polyester and other synthetic materials from neutral to slightly acid baths by procedures typically similar to the following ... 

Surface-active compounds can be produced from all wood constituents. For instance, water-soluble cellulose derivatives and lignin, in the form of lignosulfonates, can be used as dispersing agents in many applications. This chapter focuses on the production of resin and fatty acids as well as sterols and sterol ethoxylates as forest-industry by-products, and their use as surface-active components. Moreover, the potential production of hemi-celluloses and their possible utilization as steric stabilizers of oil-in-water emulsions is also outlined. 

Under eertain conditions, viscosity-reducing products and dispersing agents are necessary. Lignin sulfonate and - tannin-containing substances (e.g., quebracho, partly in chemically modified form) have such properties. 

Lignin sulfonates are, technically, low-molecular-weight polymers containing a witch s brew of primary and secondary alcohols, phenols, and carboxylic acid functionalities. They are prepared by the sulfonation of lignin byproducts of pulp and paper manufacture, followed by neutralization to the sodium, calcium, or ammonium salt. The resulting materials are useful as dispersing agents for solids and oil/water emulsions, and as stabilizers for aqueous dispersions of dyes, pesticides, and cement. They are very inexpensive relative to other materials and are very... 

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