Pyromellitic Dianhydride Property

Melting point:

283-286 °C(lit.)

Boiling point:

397-400 °C(lit.)

Density 

1,68 g/cm³

vapor pressure 

0Pa at 25℃

refractive index 

1.6000 (estimate)

Flash point:

380 °C

solubility 

Soluble in dimethyl sulfoxide, acetone, chloroform, ethyl ether, n-hexane and benzene.

form 

Fine Powder

pka

5.45[at 20 ℃]

color 

White to pale yellow

Water Solubility 

decomposes

Sensitive 

Moisture Sensitive

BRN 

213583

InChIKey

ANSXAPJVJOKRDJ-UHFFFAOYSA-N

LogP

-2.03 at 21.5℃

CAS DataBase Reference

89-32-7(CAS DataBase Reference)

NIST Chemistry Reference

1,2,4,5-Benzenetetracarboxylic anhydride(89-32-7)

EPA Substance Registry System

1H,3H-Benzo[1,2-c:4,5-c']difuran-1,3,5,7-tetrone (89-32-7)

Safety

Hazard Codes 

Xn

Risk Statements 

41-42/43

Safety Statements 

22-24-26-37/39

WGK Germany 

1

RTECS 

DB9300000

F 

10-21

TSCA 

Yes

HS Code 

29173980

Hazardous Substances Data

89-32-7(Hazardous Substances Data)

Hazard and Precautionary Statements (GHS)

Symbol(GHS)

Signal word

Danger

Hazard statements

H317May cause an allergic skin reaction

H318Causes serious eye damage

H334May cause allergy or asthma symptoms or breathing difficulties if inhaled

Precautionary statements

P261Avoid breathing dust/fume/gas/mist/vapours/spray.

P272Contaminated work clothing should not be allowed out of the workplace.

P280Wear protective gloves/protective clothing/eye protection/face protection.

P284Wear respiratory protection.

P302+P352IF ON SKIN: wash with plenty of soap and water.

P305+P351+P338IF IN EYES: Rinse cautiously with water for several minutes. Remove contact lenses, if present and easy to do. Continuerinsing.

Pyromellitic Dianhydride Chemical Properties,Usage,Production

Chemical Properties

White powder. Soluble in some organic solvents; hydrolyzes to the acid when exposed to moisture.

Uses

Pyromellitic dianhydride (PMDA) is employed as a curing agent for epoxy agent resins used for casting, laminating, the manufacture of moulding powders, adhesives and coatings.

Uses

Pyromellitic dianhydride is used as a monomer in the preparation of polyimide polymers such as kapton; thermoplastics such as polyesters, polyethers, plasticizers, and expoxy resins. It is involved in the preparation of high performance coatings due to its mechanical, thermal and oxidative stability properties. It acts as a curing agent for epoxy resins which find application in adhesives, coatings and molding powders. As an intermediate, it plays an important role in polyimide based materials like printed circuit boards, tape automated bonding and magnetic wire insulation.

Preparation

Pyromellitic Dianhydride is prepared by gas-phase oxidation of 1,2,4,5-tetramethylbenzene (or related tetrasubstituted benzene derivatives). An idealized equation is:
C6H2(CH3)4 + 6 O2 → C6H2(C2O3)2 + 6 H2O
In the laboratory, it can be prepared by dehydration of pyromellitic acid using acetic anhydride.

Application

Pyromellitic dianhydride (PMDA) has been used extensively as an important monomer in the preparation of a variety of thermoplastics such as polyesters, polycarbonates, polyethers polyethers, plasticizersplasticizers, expoxy resins, etc. Moreover, it is also useful in the preparation of high performance coatings that have been widely employed in many fields in our daily life beacuase of its excellent thermal, oxidative stability and excellent mechanical properties.
Pyromellitic dianhydride (PMDA) is one of several highly reactive acid anhydrides and used extensively in the production of thermoplastics and high-performance coatings. Anhydrides including PMDA are respiratory irritants and immediate-type sensitisers. Some anhydrides have been associated with occupational asthma. PMDA has also been related to occupational asthma.

General Description

Pyromellitic dianhydride (PMDA) is an acidic anhydride that can be used as a repair agent and as a chain extender in the formation of polyethylene terephthalate (PET) based chain extensions. It is mainly used in the production of thermoplastics and other coating applications.

Hazard

Skin irritant.

Flammability and Explosibility

Not classified

Purification Methods

Crystallise the dianhydride from ethyl methyl ketone or dioxane. Dry, and sublime it in vacuo.[Beilstein 19 H 196, 19/5 V 407.]