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Cellulose under heterogeneous conditions

Acylation of cellulose by carboxylic acid chlorides can be performed under homogeneous or heterogeneous conditions. During this reaction, the HCl released is captured by a base, most commonly pyridine or A,A-dimethylaminopyridine (DMAP) (Fig. 36). [Pg.74]

The esterification of cellulose with carboxylic acids is among the most versatile transformations leading to a wide variety of valuable products. The commercial production of cellulose esters is carried out exclusively under heterogeneous reaction conditions, at least at the beginning of the conversion, due to the high cost of solvents and the ease of work-up procedures in the case of multiphase conversions. Completely functionalized derivatives are... [Pg.343]

Acetylation in heterogeneous phase (catalyzed by mineral acids) is so called when the diluent is not a solvent of cellulose acetate. Toluene or carbon tetrachloride are such liquids. Under such conditions the original fibrillary structure is reasonably well-preserved because there is less degradation of the constituting chains. Cellulose acetates with 1.6 < D.S. < 2.0 are soluble in many solvents (acetone, esters, chlorinated solvents) and can be plasticized by alkyl phosphates or phthalates to give thermoplastic materials exhibiting a good impact resistance. [Pg.500]


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See also in sourсe #XX -- [ Pg.69 ]




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Heterogeneous conditions

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