Acetic acid

Acetic acid is a colourless liquid or crystal with a sour, vinegar-like odour and is one of the simplest carboxylic acids and is an extensively used chemical reagent. Acetic acid has wide application as a laboratory reagent, in the production of cellulose acetate mainly for photographic film and polyvinyl acetate for wood glue, synthetic fibres, and fabric materials. Acetic acid has also been of large use as a descaling agent and acidity regulator in food industries.

Acetic acid, CH3COOH, is a colorless, volatile liquid at ambient temperatures. The pure compound, glacial acetic acid, owes its name to its ice-like crystalline appearance at 15.6°C. As generally supplied, acetic acid is a 6 N aqueous solution (about 36%) or a 1 N solution (about 6%). These or other dilutions are used in adding appropriate amounts of acetic acid to foods. Acetic acid is the characteristic acid of vinegar, its concentration ranging from 3.5 to 5.6%. Acetic acid and acetates are present in most plants and animal tissues in small but detectable amounts. They are normal metabolic intermediates, are produced by such bacterial species as Acetobacter and can be synthesized completely from carbon dioxide by such microorganisms as Clostridium thermoaceticum. The rat forms acetate at the rate of 1% of its body weight per day.As a colorless liquid with a strong, pungent, characteristic vinegar odor, it is useful in butter, cheese, grape and fruit flavors. Very little pure acetic acid as such is used in foods, although it is classified by FDA as a GRAS material. Consequently, it may be employed in products that are not covered by Definitions and Standards of Identity. Acetic acid is the principal component of vinegars and pyroligneous acid. In the form of vinegar, more than 27 million lb were added to food in 1986, with approximately equal amounts used as acidulants and flavoring agents. In fact, acetic acid (as vinegar) was one of the earliest flavoring agents. Vinegars are used extensively in preparing salad dressing and mayonnaise, sour and sweet pickles and numerous sauces and catsups. They are also used in the curing of meat and in the canning of certain vegetables. In the manufacture of mayonnaise, the addition of a portion of acetic acid (vinegar) to the salt- or sugar-yolk reduces the heat resistance of Salmonella. Water binding compositions of sausages often include acetic acid or its sodium salt, while calcium acetate is used to preserve the texture of sliced, canned vegetables.

Vinegar is a dilute aqueous solution of acetic acid. The use of vinegar is well documented in ancient history, dating back at least 10,000 years. Egyptians used vinegar as an antibiotic and made apple vinegar. Babylonians produced vinegar from wine for use in medicines and as a preservative as early as 5000 b.c.e. Hippocrates (ca. 460–377 b.c.e.), known as the “father of medicine,” used vinegar as an antiseptic and in remedies for numerous conditions including fever, constipation, ulcers, and pleurisy. Oxymel, which was an ancient remedy for coughs, was made by mixing honey and vinegar. A story recorded by the Roman writer Pliny the Elder (ca. 23–79 c.e.) describes how Cleopatra, in an attempt to stage the most expensive meal ever, dissolved pearls from an earring in vinegar wine and drank the solution to win a wager.

ChEBI: Acetic acid is a simple monocarboxylic acid containing two carbons. It has a role as a protic solvent, a food acidity regulator, an antimicrobial food preservative and a Daphnia magna metabolite. It is a conjugate acid of an acetate.

A colorless aqueous solution. Smells like vinegar. Density 8.8 lb / gal. Corrosive to metals and tissue.

Acetic acid occurs in vinegar. It is producedin the destructive distillation of wood. Itfinds extensive application in the chemicalindustry. It is used in the manufacture ofcellulose acetate, acetate rayon, and variousacetate and acetyl compounds; as a solventfor gums, oils, and resins; as a food preservative in printing and dyeing; and in organicsynthesis.

Acetic acid is an important industrial chemical. The reaction of acetic acid with hydroxyl containing compounds, especially alcohols, results in the formation of acetate esters. The largest use of acetic acid is in the production of vinyl acetate . Vinyl acetate can be produced through the reaction of acetylene and acetic acid. It is also produced from ethylene and acetic acid. Vinyl acetate is polymerized into polyvinyl acetate (PVA), which is used in the production of fibers, films, adhesives, and latex paints.Cellulose acetate, which is used in textiles and photographic film, is produced by reacting cellulose with acetic acid and acetic anhydride in the presence of sulfuric acid. Other esters of acetic acid, such as ethyl acetate and propyl acetate, are used in a variety of applications.Acetic acid is used to produce the plastic polyethylene terephthalate (PET) . Acetic acid is used to produce pharmaceuticals.

Glacial Acetic Acid is an acidulant that is a clear, colorless liquid which has an acid taste when diluted with water. It is 99.5% or higher in purity and crystallizes at 17°c. It is used in salad dressings in a diluted form to provide the required acetic acid. It is used as a preservative, acidulant, and flavoring agent. It is also termed acetic acid, glacial.

Acetic acid is used as table vinegar, as preservative and as an intermediate in the chemical industry, e.g. acetate fibers, acetates, acetonitrile, pharmaceuticals, fragrances, softening agents, dyes (indigo) etc. Product Data Sheet

manufacture of various acetates, acetyl compounds, cellulose acetate, acetate rayon, plastics and rubber in tanning; as laundry sour; printing calico and dyeing silk; as acidulant and preservative in foods; solvent for gums, resins, volatile oils and many other substances. Widely used in commercial organic syntheses. Pharmaceutic aid (acidifier).

Alchemists used distillation to concentrate acetic acid to high purities. Pure acetic acid isoften called glacial acetic acid because it freezes slightly below room temperature at 16.7°C(62°F). When bottles of pure acetic acid froze in cold laboratories, snowlike crystals formedon the bottles; thus the term glacial became associated with pure acetic acid. Acetic acidand vinegar were prepared naturally until the 19th century. In 1845, the German ChemistHermann Kolbe (1818–1884) successfully synthesized acetic acid from carbon disulfide (CS2). Kolbe’s work helped to establish the field of organic synthesis and dispelled the idea of vitalism. Vitalism was the principle that a vital force associated with life was responsible for all organic substances.Acetic acid is used in numerous industrial chemical preparations and the large-scale productionof acetic acid takes place through several processes. The main method of preparation ismethanol carbonylation. In this process, methanol reacts with carbon monoxide to give aceticacid: CH3OH(l)+ CO(g)→ CH3COOH(aq). Because the reaction requires high pressures (200atmospheres), this method was not used until the 1960s, when the development of specialcatalysts allowed the reaction to proceed at lower pressures. A methanol carbonylation proceduredeveloped by Monsanto bears the company’s name. The second most common methodto synthesize acetic acid is by the catalytic oxidation of acetaldehyde: 2 CH3CHO(l)+ O2(g)→2 CH3COOH(aq). Butane may also be oxidized to acetic acid according to the reaction: 2 C4H10(l)+5O2(g)→ 4 CH3COOH(aq)+ 2H2O(l). This reaction was a major source of acetic acid beforethe Monsanto process. It is carried out at a temperature of approximately 150°C and 50 atmospheres pressure.