Esters organic

Cellulose (qv) is one of nature s most abundant stmctural materials, providing the primary framework of most plants. For industrial purposes cellulose is derived from two primary sources, cotton linters and wood pulp. Linters are derived from the machine by the same name used for removing the short fibers adhering to cotton seeds after ginning and consist essentially of pure cellulose (see Cotton). Wood (qv), on the other hand, contains 40—60% cellulose, which must be extracted by the chemical degradation of the wood stmcture. 

Cellulose esters are commonly derived from natural cellulose by reaction with organic acids, anhydrides, or acid chlorides. Cellulose esters of almost any organic acid can be prepared, but because of practical limitations esters of acids containing more than four carbon atoms have not achieved commercial significance. 

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. 

Defined as the average number of acetyl groups in the anhydroglu-cose unit of cellulose. 

Kirk-Othmer Encyclopedia of Chemical Technology (4th Edition) 

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Pancreatic lipase pancreas fats and other organic esters organic acid and alcohol (often gly ceroi) 7-0... 

To prepare the solid phenyldlazonlum chloride or sulphate, the reaction is conducted in the absence of water as far as possible. Thus the source of nitrous acid is one of its organic esters (e.g., amyl nitrite) and a solution of hydrogen chloride gas in absolute alcohol upon the addition of ether only the diazonium salt is precipitated as a crystalline solid, for example ... 

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