phthalic anhydride

phthalic anhydride 1.Good quanlity and 2.the manufacture of plasticizers, alkydresins 3.Phthalic Anhydride 4. SGS ,BV TE

phthalic anhydride

1 Phthalic anhydride is the organic compound with the formula C8H4O3. This anhydride of phthalic acid, a colourless solid, is an important industrial chemical, especially for the large-scale production of plasticizers for plastics. In 2002, approximately 4.6 billion kilograms were produced

2 Applications in industry and organic synthesis

Phthalic anhydride is a versatile intermediate in organic chemistry, in part because it is bifunctional and cheaply available. It undergoes hydrolysis and alcoholysis. Hydrolysis by hot water forms ortho-phthalic acid. This process is reversible: Phthalic anhydride re-forms upon heating the acid above 180 °C.

3 Hydrolysis of anhydrides is not typically a reversible process. However, phthalic acid is easily dehydrated to form phthalic anhydride due to the creation of a thermodynamically favorable 5-membered ring.

Organic synthesis

4 Phthalic anhydride is a precursor to a variety of reagents useful in organic synthesis. Important derivatives include phthalimide and its many derivatives. Chiral alcohols form half-esters (see above), and these derivatives are often resolvable because they form diastereomeric salts with chiral amines such as brucine. A related ring-opening reaction involves peroxides to give the useful peroxy acid:

C6H4(CO)2O + H2O2 → C6H4(CO3H)CO2H

5 Precursor to dyestuffs

6 Phthalic anhydride is widely used in industry for the production of certain dyes. A well-known application of this reactivity is the preparation of the anthroquinone dye quinizarin by reaction with para-chlorophenol followed by hydrolysis of the chloride.

Item	Index
	Top grade	First grade	Qualified product
Appearance	white scaly or crystalline powder		white scaly or crystalline powder with slight colors
molten Chroma(Chroma no. )≤	20	50	100
thermostable Chroma(Chroma no. )≤	50	150	-
Chroma of vitriol(Chroma no. )≤	60	100	150
crystallization point°C≥	130.5	130.3	130.0
Purity(mass fraction)%≥	99.50	99.50	99.00
Free acid(mass fraction)≤ %	0.20	0.30	0.50
Ash(mass fraction)%≤	0.05	-	-

phthalic anhydride