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Ortho Phthaloyl Chloride (OPC)

o-Phthaloyl Dichloride, o-Diacetyl Chloride

Product Description and Uses

Ortho-Phthaloyl Chloride (OPC) is a difunctional acid chloride, whose liquid form makes it convenient in many products. OPC is used to provide color stability in anhydrides, as a component in ceramic mold binders, in reverse osmosis membranes, in the preparation of high-temperature catalysts, and as a specialty chemical ingredient. DuPont OPC is a clear yellow liquid available in drums to customers worldwide.


Purity: 95% minimum
Appearance: Clear, yellow liquid

Typical Physical Properties*

Property  Typical Value  

CAS Registry Number  

CAS Name  1,2-Benzenedicarbonyl dichloride 
Molecular Formula   C6H4(COCl)2 
Molecular Weight    203.0 
Specific Gravity at 25°C (77°F)   1.414
Boiling Point (760 mmHg),°C (°F)   269 (516) 
Melting Point Range, °C (°F)  15–16 (59–61)   
Flash Point, COC   None to boiling  
Solubility in Water   Reacts 
Solubility in Ether     Soluble 















*These properties are drawn from various DuPont and other literature sources. DuPont does not make any warranty, express or implied, that future production will demonstrate these typical properties.

Shipping Information

OPC is a corrosive liquid, available in 600 lb net polyethylene drums.