1. Introduction and preparation of
Acetic Anhydride
Prepared By:
MIHIR PRAJAPATI:13BCH047
PRERAK SHAH:13BCH048

2. i. Molecular formula :C4H6O3.
ii. Structural formula :(CH3CO)2O
iii. Molecular weight :102.09 gmol−1
iv. Freezing point :-730C(-1000F)
v. Boiling Point(760mm Hg) :1380C(2820F)
vi. Flash Point:52.5-530C
vii.Auto-ignition Temperture:315-3310C(6290F)
viii.Specific gravity:1.082-1.083(at200C)
ix. Appearance: Colorless liquid
x. Refractive index: 1.3901
PHYSICAL PROPERTIES

3. Physical Properties:
 The lower simple anhydrides are colorless Liquids with a sharp
pungent smell.
 They are insoluble in water because of the lack of hydrogen
bonding but they dissolve because of the conversion of acetic
anhydride into an acid salt by hydrolysis.
 They have higher boiling points than the acid from which they are
derived .This is so because of their large size and enhanced van der
waal’s interactions.
 They are characterized by the c=o stretching band in IR spectrum at
frequency range 1800-1850 and 1740-1790 cm-1.
 Acetic anhydrides is a colorless liquid , 139oC ,sp gr 1.083.
 It is sparingly soluble in cold water but miscible with alcohol, ether,
and acetic acid.it gives reactions parallel to those cholorides,
although less vigorously.
• IUPAC name:
(acetic anhydride)

4.  Chemical Properties:
• Anhydrides react with nucleophiles in the same way
as acid chlorides. But since –OCOR group is not as
electronegative as Cl atom, anhydrides are less
reactive than acid chlorides.
• Thus anhydrides give all the nucleophilic substitution
reaction shown by acid chlorides but with less vigor.
• The compounds derived by loss of a water molecule
between two molecules of a carboxylic acid are called
Acid anhydrides or simply anhydrides.
• The mechanism of the nucleophilic substitution here
is the same as stated for acid chlorides with the
difference that the by-product is a molecule of the
carboxylic acid instead of HCL.
Common name:
 ethanoic anhydride.
other name:
 Ethanoyl ethanoate
 Acetic acid anhydride
 Acetyl acetate
 Acetyl oxide

5. PREPARATION
There are basically two methods of preparation of acetic anhydrides:-
1)By reaction of acid halide with a carboxylic acid
2)By reaction of acid halide with a salt of carboxylic acid

6. By reaction of acid halide with carboxylic
acid
ACID ACID
CHLORIDE
MIXED ANHYDRIDE

7. By reaction of acid halide with a salt of carboxylic acid
SODIUM
SALT
ANHYDRIDE

8.  Acetic anhydride was first synthesized in 1852 by the French chemist Charles Frédéric Gerhardt
(1816-1856) by heating potassium acetate with benzoyl chloride
1. Acetic anhydride is produced by Acetone cracking:
2. The Ketene decomposition reactions is:
3. The Acetic anhydride formation reaction is:
 To a decreasing extent, acetic anhydride is also prepared by the reaction of ketene (ethenone) with acetic acid at 45–
55 °C and low pressure (0.05–0.2 bar).
H2C=C=O + CH3COOH → (CH3CO)2O (ΔH = −63
kJ/mol)
 The route from acetic acid to acetic anhydride via ketene was developed by Wacker Chemie in 1922, when the
demand for acetic anhydride increased due to the production of cellulose acetate.

9. Production
Acetic anhydride was first synthesized in 1852 by the French chemist Charles Frédéric
Gerhardt (1816-1856) by heating potassium acetate with benzoyl chloride.
The Tennessee Eastman acetic anhydride process involves the conversion of methyl
acetate to methyl iodide and an acetate salt. Carbonylation of the methyl iodide in turn
affords acetyl iodide, which reacts with acetate salts or acetic acid to give the product.
Rhodium chloride in the presence of lithium iodide is employed as catalysts. Because
acetic anhydride is not stable in water, the conversion is conducted under anhydrous
conditions.
The route from acetic acid to acetic anhydride via ketene was developed by Wacker
Chemie in 1922, when the demand for acetic anhydride increased due to the production
of cellulose acetate.
Due to its low cost, acetic anhydride is purchased, not prepared, for use in research
laboratories.

10. Suppliers Triveni interchem Pvt.Ltd
 A.B enterprise
 Prakash chemicals Agencies Pvt.ltd
 Bhagawati Chemicals
 Iol Chemical and pharmaceuticals ltd.(Ludhiana)
 J.k Rangwals, Chemicals Pvt.Ltd(Mumbai)
 Ankit Raj Organo Chemicals Pvt.Ltd(Mumbai)
 MC India international (Jaipur)
 Organix(Mumbai)
 Kundan Rice mills Ltd(Mumbai)
per year India make average 8% of Acetic anhydride all over
World. Region Thousand metric Ton
Canada 70
Mexico 87
United states 1223
Western Europe 539

11. New research
• In the hydrosphere, Acetic anhydride is rapidly hydrolyzed (half-life 4.4 min.) to acetic acid
which is readily biodegradable
• In the atmosphere, it is converted to Acetic acid which is subject to photo oxidative
degradation (half-life 22 days).
• Toxicity to aquatic organisms is moderate (18 to 3400 mg/l), but it persists only for a short
time due to its rapid hydrolysis to acetate/acetic acid. It has virtually no potential for
bioaccumulation (log Kow = -0.27). The PEC/PNEC ratio is much less than 1, indicating
that acetic anhydride has a low potential for risk to the environment.

12. Safety:
Acetic anhydride is an irritant and combustible liquid. Because of its reactivity toward
water, alcohol foam or carbon dioxide are preferred for fire suppression. The vapour of
acetic anhydride is harmful.
When mixed with hydrogen peroxide, an excess of acetic anhydride reacts with one of
the reaction products acetic acid and forms highly shock sensitive and explosive diacetyl
peroxide.
Health hazards:
Liquid is volatile and causes little irritation on uncovered skin. However, causes
severe burns when clothing is wet with the chemical or if it enters gloves or shoes.
Causes skin and eye burns and irritation of respiratory tract. Nausea and vomiting
may develop after exposure.

13. THANK YOU