Innovations in Epichlorohydrin Manufacturing and its Expanding Applications
Epichlorohydrin (ECH) is a highly reactive, volatile organochlorine compound and a critical chemical intermediate, primarily serving as the backbone for the production of epoxy resins. Its chemical structure features an epoxide ring and a chloromethyl group, making it susceptible to nucleophilic attack at both sites. Industrially, it is produced through the chlorohydrination of allyl chloride, which involves reacting allyl chloride with hypochlorous acid to form dichlorohydrin intermediates, followed by dehydrochlorination with a base like sodium hydroxide to form ECH. An alternative, more sustainable route gaining traction is the glycerin-to-epichlorohydrin (GTE) process, which uses bio-derived glycerin (a byproduct of biodiesel production) as a feedstock, reducing reliance on petrochemical allyl chloride.
Over 90% of the world's epichlorohydrin is consumed in manufacturing epoxy resins. In this process, ECH is reacted with bisphenol-A (BPA) or other polyols to form the diglycidyl ethers that are the building blocks of epoxy polymers. These resins are foundational for protective coatings, adhesives, composites, and electronic encapsulants. ECH is also used to synthesize synthetic glycerin, water treatment resins, and certain pharmaceuticals and agrochemicals. Due to its high reactivity, volatility, flammability, and classification as a probable human carcinogen, its industrial handling requires stringent engineering controls, closed systems, and comprehensive safety protocols. The development of bio-based production routes represents a significant shift toward improving the environmental profile of this indispensable, albeit hazardous, industrial chemical.