 | Acetic acid: Encyclopedia II - Acetic acid - Applications
Acetic acid - Applications
Acetic acid is a chemical reagent for the production of many chemical compounds. The largest single use of acetic acid is in the production of vinyl acetate monomer, closely followed by acetic anhydride and ester production. The volume of acetic acid used in vinegar is comparatively small.
Acetic acid - Vinyl acetate monomer
The major use of acetic acid is for the production of vinyl acetate monomer (VAM). This application consumes approximately 40% to 45% of the world's production of acetic acid. The reaction is of ethylene and acetic acid with oxygen over a palladium catalyst.
2 H3C-COOH + 2 C2H4 + O2 → 2 H3C-CO-O-CH=CH2 + 2 H2O
Vinyl acetate can be polymerised to polyvinyl acetate or to other polymers, which are applied in paints and adhesives.
Acetic acid - Acetic anhydride
The condensation product of two molecules of acetic acid is acetic anhydride. The worldwide production of acetic anhydride is a major application, and uses approximately 25% to 30% of the global production of acetic acid. Acetic anhydride may be produced directly by methanol carbonylation bypassing the acid, and Cativa plants can be adapted for anhydride production.
Acetic anhydride is a strong acetylation agent. As such, its major application is for cellulose acetate, a synthetic textile also used for photographic film. Acetic anhydride is also a reagent for the production of aspirin, heroin, and other compounds.
Acetic acid - Ester production
The major esters of acetic acid are commonly used solvents for inks, paints and coatings. The esters include ethyl acetate, n-butyl acetate, isobutyl acetate, and propyl acetate. They are typically produced by catalysed reaction from acetic acid and the corresponding alcohol.
H3C-COOH + HO-R → H3C-CO-O-R + H2O, where R = a general alkyl group
Most acetate esters, however, are produced from acetaldehyde using the Tishchenko reaction. Additionally, some ether acetates are used as solvents for nitrocellulose, acrylic lacquers, varnish removers and wood stains. First glycol monoethers are produced from ethylene oxide or propylene oxide with alcohol, which are then esterified with acetic acid. The three major products are ethylene glycol monoethyl ether acetate (EEA), ethylene glycol monobutyl ether acetate (EBA), and propylene glycol monomethyl ether acetate (PMA). This application consumes about 15% to 20% of worldwide acetic acid. Some of these ether acetates, for example EEA, have been shown to be harmful to human reproduction.
Acetic acid - Vinegar
In the form of vinegar, acetic acid solutions (typically 5% to 18%) are used directly as a condiment, and also in the pickling of vegetables and other foodstuffs. Table vinegar tends to be more dilute (5% to 8% acetic acid), while commercial food pickling generally employs more concentrated solutions. The amount of acetic acid used as vinegar on a worldwide scale is not large, but historically, this is by far the oldest and most well-known application.
Acetic acid - Use as solvent
Glacial acetic acid is an excellent polar protic solvent, as noted above. It is frequently used as a solvent for recrystallisation to purify organic compounds. Pure molten acetic acid is used as a solvent in the production of terephthalic acid (TPA), the raw material for polyethylene terephthalate (PET). Although currently accounting for 5%–10% of acetic acid use worldwide, this specific application is expected to grow significantly in the next decade, as PET production increases.
Acetic acid is often used as a solvent for reactions involving carbocations, such as Friedel-Crafts alkylation. For example, one stage in the commercial manufacture of synthetic camphor involves a Wagner-Meerwein rearrangement of camphene to isobornyl acetate; here acetic acid acts both as a solvent and as a nucleophile to trap the rearranged carbocation. Acetic acid is the solvent of choice when reducing an aryl nitro-group to an aniline using palladium-on-carbon.
Glacial acetic acid is used in analytical chemistry for the estimation of weakly alkaline substances such as organic amides. Glacial acetic acid is a much weaker base than water, so the amide behaves as a strong base in this medium. It then can be titrated using a solution in glacial acetic acid of a very strong acid, such as perchloric acid.
Acetic acid - Other applications
Dilute solutions of acetic acids are also used for their mild acidity. Examples in the household environment include the use in a stop bath during the development of photographic films, and in descaling agents to remove limescale from taps and kettles. The acidity is also used for treating the sting of the box jellyfish by disabling the stinging cells of the jellyfish, preventing serious injury or death if applied immediately, and for treating outer ear infections in people in preparations such as Vosol. Equivalently, acetic acid is used as a spray-on preservative for livestock silage, to discourage bacterial and fungal growth.
Several organic or inorganic salts are produced from acetic acid, including:
- Sodium acetate—used in the textile industry and as a food preservative (E262).
- Copper(II) acetate—used as a pigment and a fungicide.
- Aluminium acetate and iron(II) acetate—used as mordants for dyes.
- Palladium(II) acetate—used as a catalyst for organic coupling reactions such as the Heck reaction.
Substituted acetic acids produced include:
- Monochloroacetic acid (MCA), dichloroacetic acid (considered a by-product), and trichloroacetic acid. MCA is used in the manufacture of indigo dye.
- Bromoacetic acid, which is esterified to produce the reagent ethyl bromoacetate.
- Trifluoroacetic acid, which is a common reagent in organic synthesis.
Amounts of acetic acid used in these other applications together (apart from TPA) account for another 5%–10% of acetic acid use worldwide. These applications are, however, not expected to grow as much as TPA production.
Other related archivesAcetaldehyde, Acetate, Acetic acid (data page), Acetic acid bacteria, Acetic anhydride, Acetobacter, Acetyl group, Acetyl-coenzyme A, Aluminium, Andreas Libavius, BASF, BP Chemicals, British Celanese, C2H4, C2H5OH, C4H10, C6H12O6, CH3CHO, CH3COONa, CH3I, CH3OH, CO, CO2, Carboxylic acid, Cativa, Celanese, Chloroacetic acids, Clostridium, Clostridium acetobutylicum, Copper(II) acetate, Descaling agent, E262, EU classification, Eastman, Esters, Ethanol, Ethyl acetate, European, Fatty acid, Fischer esterification, Formic acid, Friedel-Crafts alkylation, German, Greek, H2, H2O, H3C-CO-O-CH=CH2, H3C-CO-O-R, H+, HI, HO-R, Heck reaction, Hermann Kolbe, IUPAC, Jabir Ibn Hayyan (Geber), Japan, Latex, Latin, Liquid, M, Mg, Millennium Chemicals, Monochloroacetic acid, Monsanto, Monsanto process, NaHCO3, O2, Oita, Palladium(II) acetate, Pickling, Pierre Adet, Propionic acid, Renaissance, Romans, Samsung, Saturn, Showa Denko, Sodium acetate, Sterling Chemicals, Svensk Etanolkemi, Theophrastos, Tishchenko reaction, Trifluoroacetic acid, United States, Vinegar, Vosol, Wacker process, Wagner-Meerwein rearrangement, above, absorbs, acetaldehyde, acetate, acetates, acetic anhydride, acetogenic bacteria, acetyl, acetyl chloride, acetylation, acid, acid-base reactions, acidity, acidity regulator, acrylic lacquers, actinium, adhesives, air, alcohol, alkyl group, aluminium oxide, amides, anaerobic bacteria, anhydride, aniline, anion, antibacterial, apple cider, aq, aqueous, arsenic trioxide, aryl, aspirin, atm, bacteria, baking soda, base, beer, blood, boiling points, box jellyfish, brewing, butane, butanone, butyl acetate, cacodyl oxide, calcium acetate, camphor, carbocations, carbohydrates, carbon dioxide, carbon disulfide, carbon monoxide, carbon tetrachloride, carboxyl group, carboxylic acid, carboxylic acids, catalysed, catalyst, catalysts, cellulose acetate, charcoal, chemical compound, chemical element, chemical equation, chemical nomenclature, chemical reactions, chemical reagent, chlorination, chloroform, chromium, chromium(II) acetate, coatings, cobalt, coenzyme A, colour reaction, complex, condensation, condiment, convection, copper, copper(II) acetate, corrosive, crystalline, culture, descaling agents, dielectric constant, digestive system, dimers, dissociate, distillation, dry distillation, dyes, electrolytic, elements, empirical formula, ester, esters, ethanol, ethyl acetate, ethyl bromoacetate, ethylene, ethylene oxide, excreted, explosive limits, fats, fatty acids, fermentation, food additive code, food industry, foodstuffs, formaldehyde, formic acid, fungal, fungicide, g, glue, grain, grapes, greener, group, heroin, heteropoly acid, hexane, household, humans, hydrogen, hydrogen bonds, hydrophilic, hygroscopic, indigo dye, inks, inorganic, iodine, iodomethane, ion, ions, iridium, iron, iron(II) acetate, iron(III) chloride, isobutyl acetate, ketene, l, lead acetate, lead carbonate, lead poisoning, limescale, liquid, loss of water, magnesium, malodorous, malt, manganese, metabolism, metals, methane, methanol, milk of lime, miscibility, monomer, monoprotic acid, mordants, must, naphtha, nitrile rubber, nitro, nitrocellulose, nucleophile, nucleophilic acyl substitution, organic, organic synthesis, outer ear infections, oxidation, oxygen, pH, pKa, paints, palladium, perchloric acid, peroxides, petrochemical, photographic film, pickling, pigment, pigments, polar, polyethylene terephthalate, polymers, polyvinyl acetate, potato, preservative, pressures, primates, propionic acid, propyl acetate, propylene oxide, protic solvent, proton, pyrolysis, reagent, rearranged, recrystallisation, reducing, reduction, rhodium, rice, ruthenium, s, salt, silage, soil, solid, solutions, solvent, solvents, stop bath, sugars, sulfur, sulfuric acid, synthesised, temperature, terephthalic acid, tetrachloroethylene, textile, tonnes, tons, triacetin, trichloroacetic acid, triglycerides, trivial name, tungstosilicic acid, vaginal lubrication, varnish, verdigris, vinegar, vinyl acetate monomer (VAM), water, weak acid, wine, winemaking, yeast, zinc, °C
 Adapted from the Wikipedia article "Applications", under the G.N U Free Docmentation License. Please also see http://en.wikipedia.org/wiki |
