Solvent pulping

Nonconventional pulping methods such as solvent pulping, acid pulping, and biopulping are discussed in subsection 10.9.1. 

Chlorine Electrolysis of NaCl, recovery from HCl users Chemical production, plastics, solvents, pulp and paper... 

Dipropylene glycol dimethyl ether solvent, PU resins Triethylene glycol solvent, pulp/paper... 

Polysorbate 60 Propylene glycol laurate solvent, pulping Sodium xylenesulfonate solvent, PVAc Diisobutyl phthalate solvent, PVB... 

Acceptance of the solvent pulping method has been slow due to difficulties in solvent recovery. However, apparatus and technology have been developed which allow recovery of almost all the solvent. In another development, it was found that pulp bleaching can be performed more effectively in the presenee of a solvent, either methanol or ethanol. Alcohol protects cellulose during the ozone bleaching stage better than does water. Better quality cellulose is the result. 

Separation of pure cellulose requires further treatment consisting of steps that include extraction with organic solvents, pulping processes, partial hydrolysis, and dissolution and reprecipitation. Because cellulose reacts with both acids and bases and is subject to oxidation, these isolation procedures can and often do degrade the cellulose. 

Solvent Pulping. The concept of using solvents to dissolve lignin was first explored by Peter Klason in 1893. In the 1930s, Kleinert developed and patented the first solvent (organosolv) pulping process based on 50 percent aqueous ethanol. Until recently there was little incentive to pursue alternatives to the kraft process because energy and chemicals were reasonably cheap, there were few envir-... 

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