Acetic acid, cellulose ester acetate

Acetic acid, cellulose ester. See Cellulose acetate Acetic acid, cobalt (2+) salt, tetrahydrate. See Cobalt acetate (ous) Acetic acid, decyl ester, branched. See Cl 0 alkyl acetate Acetic acid, dimethyl-. See Isobutyric acid Acetic acid-1,3-dimethylbutyl ester. See Methyl amyl acetate Acetic acid-2,6-dimethyl-m-dioxan-4-yl ester Acetic acid, ester with 2,6-dimethyi-m-dioxan-4-oi. See 6-Acetoxy-2,4-dimethyl-m-dioxane Acetic acid esters of mono- and digiycerides Acetic acid esters of mono-and digiycerides of fatty acids. SeeAcetylated mono- and digiycerides of fatty acids... 

Synonyms Acetate cotton Acetate ester of cellulose Acetic acid, cellulose ester Acetose Acetylcellulose CA Cellulose, acetate Cellulose 2.5-acelate Cellulose acetate ester Cellulose. 2.5-diacetate Cellulose monoacetate Monoacetylcellulose Secondary cellulose acetate Classification Cellulosics thermoplastic resin Properties Triacetate insol. in water, alcohol, ether, sol. in glacial acetic acid tetraacetate insol. in water, alcohol, ether, glacial acetic acid, methanol pentaacetate insol. in water, sol. in alcohol m.w. 37.000 dens. 1.300... 

Acetic acid, cedrol ester. See Cedryl acetate Acetic acid, cellulose ester. See Cellulose acetate... 

Synonyms Acetate cotton Acetate ester of cellulose Acetic acid, cellulose ester Acetose Acetylcellulose... 

Cellulose acetate Acetic acid, cellulose ester 9004-3.5-7 Cellulose, acetate R (C2H402), Unk... 

Acetic anhydtide is a mature commodity chemical ia the United States and its growth rate in the 1970s and 1980s was negative until 1988 when foreign demand neatly doubled the exports of 1986. This increase in exports was almost certainly attributable to the decline in the value of the U.S. doUar. Over four-fifths of all anhydtide production is utilized in cellulose acetate [9004-35-7] manufacture (see Cellulose esters). Many anhydtide plants are integrated with cellulose acetate production and thus employ the acetic acid pyrolysis route. About 1.25 kg acetic acid is pyrolyzed to produce 1.0 kg anhydtide. 

Cellulose esters of aromatic acids, aUphatic acids containing more than four carbon atoms and aUphatic diacids are difficult and expensive to prepare because of the poor reactivity of the corresponding anhydrides with cellulose Httle commercial interest has been shown in these esters. Of notable exception, however, is the recent interest in the mixed esters of cellulose succinates, prepared by the sodium acetate catalyzed reaction of cellulose with succinic anhydride. The additional expense incurred in manufacturing succinate esters is compensated by the improved film properties observed in waterborne coatings (5). 

Mixed cellulose esters containing the dicarboxylate moiety, eg, cellulose acetate phthalate, have commercially useful properties such as alkaline solubihty and excellent film-forming characteristics. These esters can be prepared by the reaction of hydrolyzed cellulose acetate with a dicarboxyhc anhydride in a pyridine or, preferably, an acetic acid solvent with sodium acetate catalyst. Cellulose acetate phthalate [9004-38-0] for pharmaceutical and photographic uses is produced commercially via the acetic acid—sodium acetate method. 

Cellulose esters of unsaturated acids, such as the acetate methacrylate, acetate maleate (34), and propionate crotonate (35), have been prepared. They are made by treating the hydrolyzed acetate or propionate with the corresponding acyl chloride in a pyridine solvent. Cellulose esters of unsaturated acids are cross-linkable by heat or uv light solvent-resistant films and coatings can be prepared from such esters. 

Amine-containing cellulose esters, eg, the acetate A/A/-diethylaminoacetate (36) and propionate morpholinobutyrate (35), are of interest because of their unique solubiHty in dilute acid. Such esters are prepared by the addition of the appropriate amine to the cellulose acrylate crotonate esters or by replacement of the chlorine on cellulose acrylate chloroacetate esters with amines. This type of ester has been suggested for use in controlled release, mmen-protected feed supplements for mminants (36,37). 

Hydrolysis. The primary functions of hydrolysis are to remove some of the acetyl groups from the cellulose triester and to reduce or remove the combined acid sulfate ester to improve the thermal stabiUty of the acetate. 

The acetyl content of cellulose acetate may be calculated by difference from the hydroxyl content, which is usually determined by carbanilation of the ester hydroxy groups in pyridine solvent with phenyl isocyanate [103-71-9J, followed by measurement of uv absorption of the combined carbanilate. Methods for determining cellulose ester hydroxyl content by near-infrared spectroscopy (111) and acid content by nmr spectroscopy (112) and pyrolysis gas chromatography (113) have been reported. 

Acetate fibers are dyed usually with disperse dyes specially synthesized for these fibers. They tend to have lower molecular size (low and medium energy dyes) and contain polar groups presumably to enhance the forces of attraction by hydrogen bonding with the numerous potential sites in the cellulose acetate polymer (see Fibers cellulose esters). Other dyes can be appHed to acetates such as acid dyes with selected solvents, and azoic or ingrain dyes can be apphed especially for black colorants. However thek use is very limited. 

However, this method is appHed only when esterification cannot be effected by the usual acid—alcohol reaction because of the higher cost of the anhydrides. The production of cellulose acetate (see Fibers, cellulose esters), phenyl acetate (used in acetaminophen production), and aspirin (acetylsahcyhc acid) (see Salicylic acid) are examples of the large-scale use of acetic anhydride. The speed of acylation is greatiy increased by the use of catalysts (68) such as sulfuric acid, perchloric acid, trifluoroacetic acid, phosphoms pentoxide, 2inc chloride, ferric chloride, sodium acetate, and tertiary amines, eg, 4-dimethylaminopyridine. 

As in all large-scale industrial processes, the formation of the cellulose esters involves recovery of materials. Acetic anhydride is generally employed. After reaction, acetic acid and solvent are recovered. The recovered acetic acid is employed in the production of additional acetic anhydride. The recovered solvent is also reintroduced after treatment. 

Another potentially important fermentation is that producing butyric acid. The process is used industrially on only a small scale at present and details have not been disclosed. Many derivatives of butyric acid are used industrially the benzyl, methyl, octyl and terpenyl esters are used in the perfumery and essence trade and amyl butyrate, bornyl and isobornyl butyrates have been described as plasticizers for cellulose esters. Moreover vinyl butyrate is a possible ingredient of polymerizable materials. The mixed acetic and butyric acid esters of polysaccharides are also coming into favor. Cellulose acetate butyrate is marketed as an ingredient of lacquer and is less inflammable than the pure acetate. Dextran (see below) acetate butyrate may have similar uses. 

Two methods of prepn are listed in Ref 3 a)By esterification of lactic acid with ethanol and b)By combining acetaldehyde with hydrocyanic. acid to form acetaldehyde cyanohydrin, and this is treated wi th ethanol HC1 to ethyl lactate. Used as a solvent for cellulose acetate and nitrate, other cellulose esters, resins, lacquers, paints and enamels Refs l)Beil 3, 264, 267, 280,(102,109) ... 

CCOOC3Ha)2 mw 146.14, col, unstable aromatic liquid combustible but not flammable sp gr 1-079 at 20/4° (Lange), 1.09 at 20/20° (Ref 3), fr P -40.6°, bp 185-4-186° fl p 168°F v si isol in w with gradual deoompn miscible with ale, eth, eth acetate and other common org solvents. Can be prepd by standard esterification procedure using ethanol oxalic acid. The final purification, however calls for specific technique and equipment (Ref 3). Used as solvent for cellulose esters ethers and for synthetic resins also for radio tube cathode fixing lacquers, pharmaceuticals, etc... 

Cellulose acetate, which is used in textiles and photographic film, is produced by reacting cellulose with acetic acid and acetic anhydride in the presence of sulfuric acid. Other esters of acetic acid, such as ethyl acetate and propyl acetate, are used in a variety of applications. 

Cellulose dissolves in Schweitzer s reagent, an ammoniacal solution of cupric oxide. After treatment with an alkali, ibe addition of carbon disulfide causes formation of sodium xanihate. a process used in the production of rayon. Sec also Fibers. The action of acetic anhydride in the presence of sulfuric acid produces cellulose acetates, the basis for a line of synthetic materials. See also Cellulose Ester Plastics (Organic). Nitrocelluloses are produced hy ihc action of nitric acid and sulfuric acid on cellulose, yielding compounds that are highly flammable and explosive. See also Explosives. 

Cellulose esters of the 2-.. 3-. and 4-carbon acids are readily prepared by the cellulose-anhydride reaction the acetate ester and the mixed acetate butyrate and acetate propionate esters arc manufactured and used in large amounts. Esters of higher acids require different synthesis techniques and tend to be prohibitively expensive except as specialty products. Some arc in commercial production, however. Cellulose acclalc phlhalatc, for example, is manufactured for use as an enteric coating on pills. 

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