How do they make acrylic acid?

How Acrylic Acid Is Made

Acrylic acid is a key chemical used in the production of paints, adhesives, and superabsorbent polymers found in things like diapers. Despite its widespread use, few people know how it’s actually made. The most common method used today involves a chemical process called vapor phase oxidation of propylene.

Propylene, a byproduct of oil refining and natural gas processing, serves as the starting point. In industrial settings, this gas is passed through a series of high-temperature reactors—usually two in sequence—where it undergoes controlled oxidation. Each reactor uses a different catalyst specifically designed to guide the chemical transformation efficiently.

The first reactor converts propylene into acrolein, an intermediate compound. Then, in the second reactor, acrolein is further oxidized into acrylic acid. This two-step process ensures high yield and purity, minimizing unwanted byproducts. The entire reaction takes place in the vapor phase, meaning all substances involved are in gaseous form, which allows for better control and scalability in large chemical plants.

While newer methods using renewable feedstocks like bio-based lactic acid are being explored, the oxidation of propylene remains the dominant industrial approach due to its reliability and efficiency. It's a well-established process, refined over decades, and continues to meet the growing global demand for acrylic acid.

Environmental improvements and catalyst optimization are ongoing areas of research, aiming to reduce energy consumption and emissions. But for now, the two-reactor catalytic system stands as the backbone of acrylic acid production worldwide.