Cellulose-acetic acid

Cellulose Acetates or Acetyl Celluloses(AC) are esters of cellulose acetic acid, and are the most widely known org cellulose derivs they are used extensively in industry under a variety of trade names. Olsen et al(Ref 3) proposed that AC s be used as deterrents in priming compns, and PreckeI(Ref 8) patented their use as an inhibitor film on large-grain smokeless proplnts. There are also numerous applications of CA s in textiles plastics used in ordnance. The specification requirements for AC s used in proplnts are given in MIL-C-20301. See also Vol l,p A55-R under Acetyl Cellulose for addnl info on AC s... 

Cellulose Acetic acid/pyridine/conc. HCI 80 6 20 Ammonium sulfide group... 

This substance, curiously, was referred to as cellulose glycolic acid in the earlier literature, though it might have been appropriately termed cellulose acetic acid. It is referred to herein as carboxymethylcellulose, although, in many cases, the sodium salt is actually the substance under discussion. This review summarizes the literature on the chemistry and uses of carboxymethylcellulose up to the present. 

Other than the esters described, the principal organic cellulose ester manufactured is cellulose acetate acid phthalate. This product is insoluble in aqueous acidic media, but because of the free acid groups present in the pendant groups, it is soluble in aqueous basic media. It is used for enteric pill coatings. 

Acetoxypropyl-aceto cellulose/acetic acid, dibutyl phthalate [75, 62] 3C1-CTC/DEME or other solvents [57, 11]... 

Ethyloxypropyl cellulose/acetonitrile, dioxane, methanol [59] (also thermotropic) Acetoacetoxypropyl cellulose/acetic acid [62]... 

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... 

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

CH2CI2. A colourless liquid with a chloroform-like odour b.p. 4I°C. Prepared by heating chloroform with zinc, alcohol and hydrochloric acid manufactured by the direct chlorination of methane. Decomposed by water at 200°C to give methanoic and hydrochloric acids. Largely used as a solvent for polar and non-polar substances, particularly for paint removal (30%), dissolving cellulose acetate and degreasing (10%). It is more stable than carbon tetrachloride or chloroform especially towards moisture or alkali. It is somewhat toxic. U.S. production 1981 280000 tonnes. 

CH3COCH2CH1COCH3. Colourless liquid which becomes yellow on standing b.p. I9PC. Obtained by boiling 2,5-dimethylfuran with dilute sulphuric acid. It readily condenses with a variety of substances to give derivatives of furan, thiophen and pyrrole, and is a solvent for cellulose acetate. 

McjC = CHCOCH3. Colourless liquid b.p. 129"C, with a strong peppermint-like odour. Prepared by distilling diacetone alcohol in the presence of a trace of iodine. Converted to phorone by heating in propanone with dehydrating agents such as sulphuric acid. It is a solvent For cellulose acetate and ethyl-cellulose and other polymers. 

IS placed at the center of a sheet of cellulose acetate The sheet is soaked with an aqueous solution buffered at a pH of 6 0 At this pH aspartic acid C ) exists as its — 1 ion alanine as its zwittenon and lysine as its +1 ion... 

Perchloric acid Acetic acid, acetic anhydride, alcohols, antimony compounds, azo pigments, bismuth and its alloys, methanol, carbonaceous materials, carbon tetrachloride, cellulose, dehydrating agents, diethyl ether, glycols and glycolethers, HCl, HI, hypophosphites, ketones, nitric acid, pyridine, steel, sulfoxides, sulfuric acid... 

Figure 3 shows the production of acetaldehyde in the years 1969 through 1987 as well as an estimate of 1989—1995 production. The year 1969 was a peak year for acetaldehyde with a reported production of 748,000 t. Acetaldehyde production is linked with the demand for acetic acid, acetic anhydride, cellulose acetate, vinyl acetate resins, acetate esters, pentaerythritol, synthetic pyridine derivatives, terephthaHc acid, and peracetic acid. In 1976 acetic acid production represented 60% of the acetaldehyde demand. That demand has diminished as a result of the rising cost of ethylene as feedstock and methanol carbonylation as the preferred route to acetic acid (qv). 

Most of the acetic acid is produced in the United States, Germany, Great Britain, Japan, France, Canada, and Mexico. Total annual production in these countries is close to four million tons. Uses include the manufacture of vinyl acetate [108-05-4] and acetic anhydride [108-24-7]. Vinyl acetate is used to make latex emulsion resins for paints, adhesives, paper coatings, and textile finishing agents. Acetic anhydride is used in making cellulose acetate fibers, cigarette filter tow, and ceUulosic plastics. 

Currently, almost all acetic acid produced commercially comes from acetaldehyde oxidation, methanol or methyl acetate carbonylation, or light hydrocarbon Hquid-phase oxidation. Comparatively small amounts are generated by butane Hquid-phase oxidation, direct ethanol oxidation, and synthesis gas. Large amounts of acetic acid are recycled industrially in the production of cellulose acetate, poly(vinyl alcohol), and aspirin and in a broad array of other... 

About half of the wodd production comes from methanol carbonylation and about one-third from acetaldehyde oxidation. Another tenth of the wodd capacity can be attributed to butane—naphtha Hquid-phase oxidation. Appreciable quantities of acetic acid are recovered from reactions involving peracetic acid. Precise statistics on acetic acid production are compHcated by recycling of acid from cellulose acetate and poly(vinyl alcohol) production. Acetic acid that is by-product from peracetic acid [79-21-0] is normally designated as virgin acid, yet acid from hydrolysis of cellulose acetate or poly(vinyl acetate) is designated recycle acid. Indeterrninate quantities of acetic acid are coproduced with acetic anhydride from coal-based carbon monoxide and unknown amounts are bartered or exchanged between corporations as a device to lessen transport costs. 

By-product acetic acid is obtained chiefly from partial hydrolysis of cellulose acetate [9004-35-7]. Lesser amounts are obtained through the reaction of acetic anhydride and cellulose. Acetylation of saHcyHc acid [69-72-7] produces one mole of acetic acid per mole of product and the oxidation of allyl alcohol using peracetic acid to yield glycerol furnishes by-product acid, but the net yield is low. 

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. 

Fig. 1. Acetyl value and combined acetic acid for acetate esters of cellulose. Designations are as follows CA = acetate(DS = 2.4) CELL = cellulose(DS = 0) CTA = triacetate(DS = 3.0). Combined acetic acid (%) = 6005(DS)/( 159.1 + 43.04(DS)) acetyl value...

Most cellulose acetate is manufactured by a solution process, ie, the cellulose acetate dissolves as it is produced. The cellulose is acetylated with acetic anhydride acetic acid is the solvent and sulfuric acid the catalyst. The latter can be present at 10—15 wt % based on cellulose (high catalyst process) or at ca 7 wt % (low catalyst process). In the second most common process, the solvent process, methylene chloride replaces the acetic acid as solvent, and perchloric acid is frequentiy the catalyst. There is also a seldom used heterogeneous process that employs an organic solvent as the medium, and the cellulose acetate produced never dissolves. More detailed information on these processes can be found in Reference 28. 

The precipitated cellulose acetate is filtered from the dilute (25—36%) acetic acid. The acetic acid and salts remaining from the sulfuric acid neutrali2ation are removed by washing. The wet polymer is typically dried to a moisture content of 1—5%. The dilute acetic acid obtained from the washing and precipitation steps caimot be used in other stages of the process. Its efficient recovery and recycle are an economic necessity. 

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