For professionals in chemical synthesis and materials science, a deep understanding of a compound's chemical properties is fundamental to its successful application. 4-Phenylethynylphthalic Anhydride (4-PEPA), CAS 119389-05-8, is a molecule that offers a fascinating combination of structural features and reactivity. As a dedicated manufacturer and supplier of this intermediate, we wish to share insights into its key chemical characteristics.

At its core, 4-PEPA is a derivative of phthalic anhydride, a well-known cyclic anhydride. The defining feature is the phenylacetylenyl (phenylethynyl) substituent attached at the 4-position of the phthalic anhydride ring. This structural design—C16H8O3 with a molecular weight of 248.23 g/mol—makes it a bifunctional molecule. The anhydride group is inherently reactive, readily undergoing nucleophilic attack by alcohols, amines, and water to form esters, amides, and the corresponding phthalic acid, respectively. This reactivity is precisely what makes it so valuable in polymerization processes and organic synthesis.

The melting point of 4-PEPA is consistently reported around 152°C. This relatively sharp melting point is indicative of a crystalline solid and is a key parameter for quality control. The physical appearance, typically described as a light yellow to light yellow-green powder or crystal, also provides a visual cue to its purity and form. While soluble in many organic solvents like DMF, DMSO, and hot toluene, it is practically insoluble in water, which is common for many anhydrides and influences handling and reaction conditions.

The phenylethynyl group itself adds another layer of chemical interest. The triple bond is a site of potential reactivity, such as in cycloaddition reactions or further functionalization. However, in the context of its primary use as a capping agent for polyimides, its role is more often structural—imparting rigidity and enhancing thermal stability to the resulting polymer chains. This phenyl-acetylene moiety contributes to the high glass transition temperatures and excellent thermal decomposition resistance observed in PEPA-derived polyimides.

Safety information, often detailed in Material Safety Data Sheets (MSDS), is critical. While specific hazards may vary, anhydrides in general can be irritants to skin, eyes, and respiratory tracts. Proper handling, including the use of personal protective equipment (PPE) such as gloves, safety glasses, and in well-ventilated areas or fume hoods, is essential. Understanding these properties allows us to provide appropriate handling guidelines to our customers who purchase 4-phenylethynylphthalic anhydride.

As a manufacturer, our focus is on producing 4-PEPA with consistent chemical properties, ensuring that each batch meets the high standards required for advanced material synthesis. We understand that reliable chemical data is crucial for our clients’ research and production. Therefore, when you buy 4-PEPA from us, you can expect detailed specifications and support to ensure its effective use in your applications. Explore the chemical potential of 4-PEPA for your next project by sourcing it from a trusted China supplier.