Eastman Chemical acetic anhydride

Eastman Goal Chemicals. In 1983 Eastman Chemical Co. became the first chemical producer in the United States to return to coal as a raw material for large-scale manufacture of industrial chemicals (35). In that year, Eastman started manufacturing acetic anhydride from coal. Acetic anhydride is a key intermediate for production of coatings, ceUulosic plastics, and cellulose acetate fibers. Acetic anhydride from other sources also is used in the manufacture of pharmaceuticals, starches and sweeteners, and flavors and fragrances. 

The Eastman Chemicals from Coal faciUty is a series of nine complex interrelated plants. These plants include air separation, slurry preparation, gasification, acid gas removal, sulfur recovery, CO /H2 separation, methanol, methyl acetate, and acetic anhydride. A block flow diagram of the process is shown in Eigure 3. The faciUty covers an area of 2.2 x 10 (55 acres) at Eastman s main plant site in Kingsport, Teimessee. The air separation plant is... 

The chemical complex includes the methanol plant, methyl acetate plant, and acetic anhydride plant. The methanol plant uses the Lurgi process for hydrogenation of CO over a copper-based catalyst. The plant is capable of producing 165,000 t/yr of methanol. The methyl acetate plant converts this methanol, purchased methanol, and recovered acetic acid from other Eastman processes into approximately 440,000 t/yr of methyl acetate. 

Production of Eastman s entire acetic anhydride requirement from coal allows a reduction of 190,000 m /yr (1.2 million barrels/yr) in the amount of petroleum used for production of Eastman chemicals. Now virtually all of Eastman s acetyl products are made in part from coal-based feedstocks. Before the technology was introduced, these chemicals had been made from petroleum-based acetaldehyde. Reduced dependence on petroleum, much of which must be obtained from foreign sources, is important to maintain a strong domestic chemical industry. 

With the takeover of the American Celanese Corp. in mid-1986, the new Hoechst Celanese Corp., with Eastman Chemical Co. are the world leaders in cellulose acetate tow and flake production as of this writing. With confidence in both the acetate market and acetic anhydride supply (105), Hoechst... 

Eastman Chemical Company has operated a coal-to-methanol plant in Kingsport, Tennessee, since 1983. Two Texaco gasifiers (one is a backup) process 34 Mg/h (37 US ton/h) of coal to synthesis gas. The synthesis gas is converted to methanol by use of ICl methanol technology. Methanol is an intermediate for producing methyl acetate and acetic acid. The plant produces about 225 Gg/a (250,000 US ton/a) of acetic anhydride. As part of the DOE Clean Coal Technology Program, Air Products and Cnemicals, Inc., and Eastman Chemic Company are constructing a 9.8-Mg/h (260-US ton/d) slurry-phase reactor for the conversion of synthesis gas to methanol and dimethyl... 

The most successful example of generating chemicals directly from coal is the Tennessee Eastman integrated process for producing acetic anhydride. The commercial plant gasifies approximately 900 tons of coal per day and performs four chemical steps to yield annually 500 million pounds of acetic anhydride, 390 million pounds of methyl acetate, and 365 million pounds of methanol. In addition, 150 million pounds per year of acetic acid may be produced from acetic anhydride. 

Methanol is an ideal starting material for the synthesis of many chemicals. It is the most important feedstock for the large-scale commercial production of acetic acid and formaldehyde. Additionally, a variety of other chemicals such as methyl esters, methyl halides and methyl ethers can be produced from it. Tenessee-Eastman s recent pioneering commercialization of a coal-based process for acetic anhydride production illustrates the growing importance of methanol as chemical feedstock. 

Higher crude oil prices had revived studies in the use of coal as a chemical feedstock. But while the Fischer-Tropsch synthesis was still used in South Africa by Sasol, the only other industrial gasification unit was the one Eastman Kodak brought on stream in Kingsport, Tennessee, in 1983, to produce coalbased acetic anhydride. The coal came from the Appalachian mountains and was cheap enough relative to oil prices at the time to warrant such an installation, and the plant is now to be expanded. 

In 1980, the Tennessee Eastman unit of Eastman Kodak announced that it would begin construction of a facility to make acetic anhydride from coal, which was readily available at reasonable cost.17 18 This decision reflected a changing of the raw materials base of much of the chemical industry due to such factors as the rising cost of natural gas and petroleum and the large coal reserves of the United States. 

In recent years several commercial plants have been constructed for conversion of coal to synthesis gas for chemical manufacturing. These include the Eastman Chemical s acetic anhydride plant, the Ube (Japan) ammonia plant, the SAR (Germany) oxo chemicals plant, and several coal to ammonia plants in China (e.g., Weihe, Huainan, and Lunan). The Ube plant and the SAR plant have since converted to lower-cost opportunity fuels (petroleum coke and residues). The Eastman plant is still operating exclusively on coal. Feedstock changes at the other plants illustrate the vulnerability of coal conversion processes to a changing economic climate. The fact that the Eastman process remains competitive under changing conditions is due to a set of special circumstances that favor a coal-based process. The success of the Eastman chemicals from coal complex demonstrates that synthesis gas from coal is a viable feedstock for some industrial chemicals under certain conditions. 

The recovery of heavy metals from solid waste poses more challenges. The Eastman Chemical Company process for the manufacture of acetic anhydride by the carbonylation of methyl acetate involves a proprietary process for the continuous recovery of rhodium and lithium from the process tar (see Section 4.6). 

The main difference between the Monsanto acetic acid process and Tennessee Eastman acetic anhydride process is the presence of water in the acetic acid process, which produces HI and acetic acid. In both reactions, a small amount of H2 is added to the CO stream to act as a reducing agent to keep the catalyst in the more active Rh oxidation state. An engineering problem with both processes is the highly corrosive nature of the Hl/iodide mixture, requiring the use of special chemically resistant alloys, pumps, and seals. 

Eastman Chemical Company, together with Halcon, developed a commercial acetic anhydride process to an industrial scale [41b, 47]. This process starts with coal to make a hydrogen-rich synthesis gas, which is purified (Figure 4). A portion of the syn gas is separated to produce methanol from 2 1 H2/CO. Part of the methanol is used to scrub H2S from the coal-gasification step. The remainder of the methanol is combined with acetic acid to make methyl acetate. The methyl acetate is carbonylated to give acetic anhydride. The acetic anhydride is used to produce cellulose acetate in another process, and the resulting acetic acid is recycled to the esterification section. The acetic anhydride step of the pro-... 

On the basis of this development afforded by Eastman and Halcon, in 1983 the Eastman Chemical Company (Kingsport, TN) started the commercial process for the manufacture of acetic anhydride (Figure 5). Methyl acetate, the feedstock for the carbonylation reaction, was produced in a separate esterification step from acetic acid and methanol. The process was designed to produce 225 000 tons of acetic anhydride and 75 000 tons of acetic acid/year. The overall yield of acetic anhydride based on methanol is approximately 96 % [2, 47]. 

Because acetic anhydride is more useful to the chemical industry than acetic acid, there was economic incentive to develop a process that would yield the anhydride directly without first producing the acid as a separate operation. By the early 1980s, Eastman Chemicals, in conjunction with Halcon Chemical Company, developed a procedure that provided acetic anhydride using technology similar to the Monsanto process, and since 1991 a plant run by Eastman has produced anhydride in excess of 500,000 metric tons per year.89 The Eastman-Halcon (E-H) operation amounts formally to inserting CO into the C-0 bond of methyl acetate according to equation 9.36.90... 

Acetic anhydride is used in the manufacture of cellulose acetate-based film, cigarette filters, and plastics. Eastman Chemical developed a process that is based on gasification of coal in a Texaco gasifier to make synthesis gas which then is converted to methanol. The methanol is converted to methyl acetate by esterification with acetic acid and then carbonylated. The carbonylation process uses rhodium salt catalysts with ligands and an iodine promoter [30]. 

Acetic anhydride capacity in the United States in 1995 was approximately 2960 million lbs./year. Forty five percent of this total is produced by Eastman Chemical by methyl acetate carbonylation in their coal to chemicals plant. The remainder is produced by others using the ketene cracking route [11]. 

Acetic Anhydride. Cellulose acetate derived from acetic anhydride is used to make cigarette filter tow. Demand has begun to decline and is expected to continue this downward trend. It is also used by Eastman Chemical as an intermediate to make photographic film base, Tenite cellulose plastics, textile chemicals, and coating chemicals [13]. 

The period from 1970 to 1985 saw radical changes in the production of acetic acid and acetic anhydride. By 1985, both products would be generated not from ethylene, but from synthesis gas which in turn could be generated fi om abundant resources such as coal, natural gas, and in the future, biomass. At the end of this period, acetaldehyde became a very small contributor to the total acetyl product stream since it was no longer required to make acetic acid or acetic anhydride and ethylene would only be required to produce vinyl acetate and to meet a much diminished acetaldehyde market. These advances were the result of two significant process breakthroughs - the Monsanto Acetic Acid Process and the Eastman Chemical Company Acetic Anhydride Process which will be discussed below. 

The Eastman Chemical Company Acetic Anhydride Process/ "... 

In 1983 Eastman Chemical Company began operating a facility to convert coal to acetic anhydride. This represented the first modem chemicals from coal facility and used coal based synthesis gas to generate acetic anhydride. The lynchpin technologies were a unique, first of its kind, reactive distillation of acetic acid and methanol to generate methyl acetateand the subsequent carbonylation of methyl acetate to generate acetic anhydride. 

While the process was commercialized in 1983, Eastman Chemical Company and Halcon began a joint development of the Rh catalyzed carbonylation of methyl acetate to acetic anhydride in the late 1970 s. While the catalyst was similar to the Rh catalyst used in the Monsanto process, there were some unique challenges since (i) under anhydrous conditions the active catalyst, Rh(CO)2l2, failed to form, (ii) unlike water, acetic acid did not react with acetyl... 

Similar intermediates are possibly involved in the Halcon/Eastman route to acetic anhydride from methyl acetate ", and BP Chemicals acetic acid/acetic anhydride co-production process, both now commercialized. However, all these cyclic mechanisms may be incomplete, as individual steps may themselves be complex or catalysed by other species present, and the author has omitted many (minor) side-reactions. 

In 1983, Eastman Kodak commissioned a 250 kt per annum acetic anhydride plant based on this technology in Kingsport, Tennessee a second plant was commissioned in late 1991, and this route now provides about 60% of the U.S. acetic anhydride capacity. The sting in the tail is that the whole complex is based on the gasification of coal. In contrast, BP Chemicals newest 200 kt per annum carbonylation plant in the U.K., commissioned in 1989 for the simultaneous production of acetic acid and anhydride, is based on natural gas. 

Carbonylation of Methyl Acetate Eastman Chemical s Acetic Anhydride Process... 

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