ACETIC ANHYDRIDE

PRODUCT IDENTIFICATION

CAS NO.

108-24-7

ACETIC ANHYDRIDE

EINECS NO. 203-564-8
FORMULA

C4H6O3

MOL WT.

102.09

H.S. CODE

2915.24
TOXICITY Oral rat LD50: 1780 mg/kg
SYNONYMS Acetic oxide; Acetyl oxide; Ethanoic Anhydride;
Acetic acid anhydride; Acetyl ether; Hydroxybiacetyl; Ethanoic Anhydrate; Acetanhydride; Anhydride Acetique; Anhydrid kyseliny octove; Anidride acetica; Azijnzuuranhydride; Essigsaeureanhydrid; Octowy bezwodnik; Acetyl acetate
DERIVATION

 

CLASSIFICATION

 

GENERAL DESCRIPTION

Acetic Anhydride is a clear, colorless liquid with a very pungent, penetrating, vinegar-like odor that combines with water to form acetic acid. It is soluble in ether, chloroform and benzene. It reacts with alcohols Acetic anhydride is prepared commercially in either of two ways. : Acetaldehyde is converted into acetic anhydride by atmospheric oxidizing the liquid acetaldehyde in the presence of a metal acetate as the catalyst (Oxidation process). ; The ketene (or acetylene) created form hot vapor of acetic acid is converted into acetic anhydride by reacted with acetic acid (Ketene process). The acyl groups (RCO) in organic anhydrides favor wide range of organic synthesis. They react with water to give carboxylic acids, with alcohols or phenols to give esters, and with ammonia and amines to give amides. Acetic anhydride is used in the manufacture of cellulose acetate having the application as a base for magnetic tape and in the manufacture of textile fibres. Also, it is heated with salicylic acid to produce acetylsalicylic acid (aspirin). It is also used in the manufacture of pigments, dyes, cellulose and pesticides etc.

PHYSICAL AND CHEMICAL PROPERTIES

PHYSICAL STATE

Clear liquid, Strong acetic odor

MELTING POINT

- 73C

BOILING POINT

140C

SPECIFIC GRAVITY

1.082

SOLUBILITY IN WATER

Slowly soluble (Decomposes)

pH  
VAPOR DENSITY

3.52

AUTOIGNITION

 

NFPA RATINGS

Health: 3; Flammability: 2; Reactivity: 1

REFRACTIVE INDEX

 
FLASH POINT  
STABILITY Flammable gas

APPLICATIONS

Cellulose acetate, cellulose triacetate, cellulose mixed ester plastics, coatings, pesticides and pharmaceuticals.
SALES SPECIFICATION

APPEARANCE

Clear liquid

PURITY

99.50 % max

ACETIC ACID

0.50 % max

COLOR

10 Pt-Co Scale

PERMANGANATE TIME

10 min (minutes)

ALUMINUM

1 max (mg/kg)

IRON

1 max (mg/kg)

HEAVY METALS (as Pb)

1 max (mg/kg)

NONVOLATILES

0.003 max (g/100 ml )

CHLORIDES

1 max (mg/kg)

SULFUR

1 max (mg/kg)

PRECAUTION IN HANDLING
Protect against physical damage. Store in a cool, dry well-ventilated location, away from any area where the fire hazard may be acute. Outside or detached storage is preferred. Separate from incompatibles. Containers should be bonded and grounded for transfers to avoid static sparks. Storage and use areas should be No Smoking areas. Use non-sparking type tools and equipment, including explosion proof ventilation. Keep away from water. This material is corrosive to steel, galvanized iron, copper and copper alloys. Containers of this material may be hazardous when empty since they retain product residues (vapors, liquid); observe all warnings and precautions listed for the product

TRANSPORTATION

PACKING  
HAZARD CLASS 8
UN NO.

1715

OTHER INFORMATION
Hazard Symbols: C, Risk Phrases: 10-20/22-34, Safety Phrases: 26-36/37/39-45

GENERAL DESCRIPTION OF ANHYDRIDE

Anhydride is a compound formed by the abstraction of a molecule of water, H2O, from a substance. The term acid anhydride is restricted sometime to the anhydride formed especially from an acid by dehydration or one that revert to the original substance upon hydration. In case of bimolecular, it can be composed of two molecules of the corresponding acid. The term mixed anhydride is an acid anhydride composed of two different acids. Examples are adenosine triphosphate or an aminoacyl adenylate. The anhydrides of bases are oxides.

Anhydrides of inorganic acids are usually oxides of nonmetallic elements. Carbon dioxide (CO2) is the anhydride of carbonic acid, dinitrogen pentoxide (N2O5) is the anhydride of nitric acid, sodium oxide is an anhydride of sodium hydroxide, phosphorus pentoxide (P2O5) is the anhydride of phosphoric acid, and sulfur trioxide (SO3) is the anhydride of sulfuric acid. An acid anhydride forms an acid; a base anhydride forms a base. Sulfur trioxide (acid anhydride) reacts with water to form sulfuric acid (an acid product). Calcium oxide (an base anhydride) reacts with water to form calcium hydroxide (a base product).

Organic anhydrides contain the carbonyl group (CO). Organic anhydrides are formed by the condensation of original acids. Lactone, an internal cyclic monoester, is an anhydride derived from the hydroxyl and carboxyl radicals. In organic chemistry, most anhydride compounds are derived from corresponding carboxylic acids. Carboxylic anhydrides, general formula (RCO)2O, are the dehydration product of two carboxylic acid molecules. The name of carboxylic anhydride is given first from the original acid, followed by the separate word "anhydride". [CH3(CH2)2CO]2O is butanoic anhydride, CH3COOCOCH2CH3 is ethanoic propanoic anhydride (or acetic propionic anhydride). Anhydrides are more reactive than the parent acids. Anhydrides are typically not target molecules, but rather they are used as intermediates for the synthesis of other organic members such as esters and amides for the industrial applications include dyes, pharmaceuticals, pesticides, plastics, fibers, curing agents, plasticizers and many others. The reactivity of carboxylic acid derivatives are in order of acyl halides > anhydrides >> esters acids >> amides.  Anhydrides react with alcohols to form esters; acetic anhydride [(CH3CO)2O] reacts with ethanol (C2H5OH) to form ethyl acetate (CH3COOC2H5) used as a common solvent. Anhydrides also react with ammonia and primary or secondary amines to form amides. Anhydrides react with water to form their corresponding acids.