Acetic anhydride Acetone, 31 Table

Cellulose acetate [9004-35-7] is the most important organic ester because of its broad appHcation in fibers and plastics it is prepared in multi-ton quantities with degrees of substitution (DS) ranging from that of hydrolyzed, water-soluble monoacetates to those of fully substituted triacetate (Table 1). Soluble cellulose acetate was first prepared in 1865 by heating cotton and acetic anhydride at 180°C (1). Using sulfuric acid as a catalyst permitted preparation at lower temperatures (2), and later, partial hydrolysis of the triacetate gave an acetone-soluble cellulose acetate (3). The solubiUty of partially hydrolyzed (secondary) cellulose acetate in less expensive and less toxic solvents such as acetone aided substantially in its subsequent commercial development. 

A freshly calcined zeolite catalyst was added to a mixture of 2,3-dimethyl-2-butene (1), acetic anhydride, and chlorobenzene (internal standard). The suspension was stirred at room temperature or heated for a few hours (see Tables for details). The solid was filtered off with suction and rinsed with acetone. The filtrate was analysed by GC on a Pye Unicam Series 104 chromatographic system using a glass coliunn packed with SE-30 stationary phase. A sample of pure 3,3,4-trimethyl-4-penten-2-one (2) was prepared and characterised according to literature indications [ 13] and used for calibration. Yields were determined using the internal standard method. 

Ionic liquids are promising new solvents in the field of cellulose shaping and functionalization. The acylation of cellulose dissolved in an ionic liquid can be carried out with acetic anhydride. The reaction succeeds without an additional catalyst. Starting from DS 1.86, the cellulose acetates obtained are acetone soluble [21], The control of the DS by the prolongation of the reaction time is possible. When acetyl chloride is used, complete acetylation is achieved in 20 min (Table 16.1) [18, 22, 23], This method may lead to a widely applicable acylation procedure for polysaccharides, if the regeneration of the solvent becomes possible. 

There have been extensive investigations of the preparation of ketene by the pyrolysis of acetone, acetic acid, acetic anhydride, and other substances. The various compounds which have been subjected to pyrolysis in studies of the production of ketene and its homologs are listed in Table... 

Like the vinyl ethers, isopropenyl acetate does not readily form homopolymers by free radical initiation. It does participate in the donor-acceptor mode of polymerization with maleic anhydride and the copolymer was made by free radical polymerization (see Table III). When attempts were made to measure molecular weight by GPC using THF as a solvent on STYRAGEL columns, the polymer did not elute. Therefore, viscosity in acetone at 30"C was used as a measure of molecular size changes on irradiation. The changes on exposure... 

The 24 hour photolysis of chlorendic anhydride (III) in acetone in the presence of diethoxyacetophene (IV) yielded at least twelve measurable products as observed by the GC/MS procedure (Table I). Some of the products observed, i.e. 4-methyl-4-hydroxy-2-pentanone, biacetal, 4-methyl-3-pentene-2-one, ethyl acetate, 3-methyl-3-hy-droxy-2-butanone, 4-methyl-2-pentanone, and 2,4-pentane-dlone, are clearly derived from the photochemically induced decomposition of acetone and/or dlethoxyacetophe-none. 

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