Acetaldehyde from plants

Up to 600 tons of methylmercury were discharged into Minamata Bay, Japan, between 1932 and 1971 from acetaldehyde manufacturing plants. Human fatalities were documented beginning in 1953 from consumption of methylmercury-contaminated fish and shellfish from the Bay. By 1993, about 2000 victims of Minamata Disease were identified including more than 100 deaths and 59 congenital birth defects from a total regional population of about 200,000 however, at least 10,000... 

Your company has asked your group to determine whether this new technology should be used in your Gulf Coast plant. Your job is to design a process and plant to produce 100 MM Ib/yr of acetaldehyde from acetic acid, which is available on the site. Based on past experience, you know that you will have to defend any decisions you have made throughout the design, and the best defense is economic justification. 

As another example of the value of enzymological studies, the major enzymes of the benzylisoquinoline alkaloid pathway have also been isolated from plant tissue culture and studied by Zenk and co-workers (see Chapter 34) (Fig. 1.2). An enzyme, (S)-norlaudanosoline synthase, which catalyzes the conversion of dopamine and (3,4-dihydroxyphen-yl)acetaldehyde (9) into (S)-norlaudanosoline (10) has been purified about 40-fold from cell suspension cultures of Eschscholtzia tenuifolia (see also cluster 32 for up-dated in-... 

Karl, T, Curtis, A.I, Rosenstiel, T.N., Monson, R.K., Fall, R. (2002) Transient releases of acetaldehyde from tree leaves—products of a pyruvate overflow mechanism Plant, Cell Environment, 25,1121-1131. 

Volatiles emitted by plants serve many purposes for example, they attract pollinators, seed disseminators and natural enemies of attacking insects [201]. They are also used as signals of stress, they can have antimicrobial properties, and they can serve to warn neighbouring plants of potential attack [202-208]. Using various analytical measurements, 1700 VOCs have been identified from more than ninety plant families [200]. Many of these volatiles are found to be oxygenated (e.g. formic and acetic acids, acetone, formaldehyde, acetaldehyde, methanol and ethanol). However, in terms of emission rates from plants, isoprene and monoterpenes are quantitatively the largest [88]. 

Acetaldehyde, first used extensively during World War I as a starting material for making acetone [67-64-1] from acetic acid [64-19-7] is currendy an important intermediate in the production of acetic acid, acetic anhydride [108-24-7] ethyl acetate [141-78-6] peracetic acid [79-21 -0] pentaerythritol [115-77-5] chloral [302-17-0], glyoxal [107-22-2], aLkylamines, and pyridines. Commercial processes for acetaldehyde production include the oxidation or dehydrogenation of ethanol, the addition of water to acetylene, the partial oxidation of hydrocarbons, and the direct oxidation of ethylene [74-85-1]. In 1989, it was estimated that 28 companies having more than 98% of the wodd s 2.5 megaton per year plant capacity used the Wacker-Hoechst processes for the direct oxidation of ethylene. 

Although acetic acid and water are not beheved to form an azeotrope, acetic acid is hard to separate from aqueous mixtures. Because a number of common hydrocarbons such as heptane or isooctane form azeotropes with formic acid, one of these hydrocarbons can be added to the reactor oxidate permitting separation of formic acid. Water is decanted in a separator from the condensate. Much greater quantities of formic acid are produced from naphtha than from butane, hence formic acid recovery is more extensive in such plants. Through judicious recycling of the less desirable oxygenates, nearly all major impurities can be oxidized to acetic acid. Final acetic acid purification follows much the same treatments as are used in acetaldehyde oxidation. Acid quahty equivalent to the best analytical grade can be produced in tank car quantities without difficulties. 

Synthol coproducts include alcohols, ketones, and lower paraffins. They are used mainly as solvents in the paint and printing industries, although some alcohols are blended into fuels. In 1992 Sasol began producing 17,500 t/yr 1-butanol [71-36-3] from 5-07-acetaldehyde [75-07-0] and plaimed to start a plant to produce high purity ethanol [64-17-5] in 1993. Acetone [67-64-1] and methyl ethyl ketone [78-93-3] are two ketone coproducts sold as solvents. 

Commercial VPO of propane—butane mixtures was in operation at Celanese Chemical Co. plants in Texas and/or Canada from the 1940s to the 1970s. The principal primary products were acetaldehyde, formaldehyde, methanol, and acetone. The process was mn at low hydrocarbon conversion (3—10%) and a pressure in excess of 790 kPa (7.8 atm). These operations were discontinued because of various economic factors, mainly the energy-intensive purification system required to separate the complex product streams. 

Direct Hydration of Ethylene. Hydration of ethylene to ethanol via a Hquid-phase process cataly2ed by dilute sulfuric acid was first demonstrated more than a hundred years ago (82). In 1923, the passage of an ethylene-steam mixture over alumina at 300°C was found to give a small yield of acetaldehyde, and it was inferred that this was produced via ethanol (83). Since the late 1920s, several industrial concerns have expressed interest in producing ethanol synthetically from ethylene over soHd catalysts. However, not until 1947 was the first commercial plant for the manufacture of ethanol by catalytic hydration started in the United States by Shell the same process was commerciali2ed in the United Kingdom in 1951. 

The plant began full-scale operation in 1962 and produced acetic, adipic, and propionic acids acetaldehyde butanol hexamethyldiamine vinyl acetate nylon and other chemical products from petroleum-base stocks. The effluent was collected at waste treatment facilities as two separate mixtures. Because mixing two wastestreams produced considerable precipitation, the wastestreams were processed and injected separately into two wells. 

A few plants have been built to oxidize normal paraffins such as propane and butane. Air and paraffin are charged to a tubular furnace at a temperature of about 700 R Acetaldehyde yields from butane are about 30—35%. 

For a simple specific example, the tetrahydroisoquinoline alkaloid salsolinol is found in some plants, and it can also be detected in the urine of humans as a product from dopamine and acetaldehyde. 

FIGURE 4.6 Development of acetaldehyde concentrations during the microoxygenation of a Merlot wine for (A) a 141-L pilot plant study and (B) a 2400-L study. Reprinted with permission from Carlton et al. (2007). Copyright 2007 American Chemical Society. 

Another oxo plant, now being constructed, will make butyl compounds (88). These may be the source of butyl alcohol, butyl acetate, butyric acid for the manufacture of cellulose acetate butyrate and other products, butyraldehyde for polyvinyl butyral, and the eight-carbon compounds including 2-ethylhexanol. All these will add to the present production of the same compounds made by the older methods from acetaldehyde via aldol condensation. 

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