Cellulose acetate maturation

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. 

Acetic anhydride is one of the most important esters. The major market for acetic anhydride is in the production of cellulose acetate Other important uses Include production of cellulosic plastics, vinyl acetate, and aspirin. Acetic anhydride is u mature commercial product enjoying a stable price situation and steady growth... 

Jawaheer et al. [12] Fruits (maturity and quality) Glucose oxidase, mutarotase, invertase/ pectin matrix and covered with a cellulose acetate (CA) membrane Screen-printed rhodinised carbon electrodes/ +350mV vs. Ag/AgCl ... 

Maturation of Cellulose Acetate and the Introduction of Vinyl Acetate. (1920-1950)... 

Over the next 30 years, wood distillation declined relative to ethanol dehydrogenation and acetylene based processes as a source of acetyls, but all three would contribute to the acetyl supply chain required to generate the acetic anhydride needed to meet the market demands for cellulose acetate as the product grew and matured over the period 1920-1940. However, while cellulose acetate and cellulose ester markets would grow, improvements in technology for the basic acetyl products were limited during this time period. 

Cellulose acetate is a mature product and growth has declined in many areas of the world except China. In 1987, the Chinese government decided to produce filtered cigarettes. Production of filtered cigarettes in China grew from almost 0% in 1987 to 97.3% on 2000. Per capita cigarette use is growing in Eastern Eimope and other Asian countries. China s demand for cellulose acetate tow is only partially supplied by domestic product. Increased manufactin-e in China is expected, but will just replace imports since the market is now matin-e (103). 

The greatest use of acetic anhydride is in esterifying cellulose to cellulose acetate for application as cigarette filter tow and in textiles. In the United States, acetic anhydride is manufactured by cellulose acetate manufacturers and largely used internally. Other products using acetic anhydride as a raw material are mostly mature with low growth rates they include triacetin, plastic modifiers and intermediates for pharmaceuticals, herbicides, pesticides, and dyes for polyolefins. Growth in production was projected to be 2.1 percent/year in the United States and less in Western Europe and Japan from 1988 to 1995. 

The two associative thickeners examined in the remainder of this text whose synthesis has not been discussed are hydrophobe-modified alkali-swellable emulsions (HASE) discussed in Chapters 25, 27, and 28, and hydrophobe-modified (hydroxyethyl)cellulose (HMHEC, discussed in Chapters 17, 18, and 27). HASE thickeners, by far the lowest cost hydrophobe-modified thickeners produced, should have achieved the largest market share on the basis of cost of production, but this situation does not appear to be the case (discussed in Chapter 28) in large part because of the poor properties observed with the lowest cost latex, vinyl acetate, used to form the continuous film. The applied-film properties 46) of vinyl acetate can be substantially improved through the use of HEUR polymers. HMHEC, synthesized by a matured (30-year-old) commercial slurry process (47) has achieved commercial acceptance, in large part because of linear high shear rate viscosities achieved in blends with HEUR thickeners (Chapter 27). 

---