Engineers boost sustainable acrylic acid production using next‑generation membrane reactor - Engineering - Energy & Green Tech

This image was generated by AI for the research team, to represent the acrylic acid production method. Credit: University of Manchester

Acrylic acid is essential for everyday products—from paints and coatings to absorbent polymers—yet almost all of it is currently made from propylene, a petrochemical. As global biodiesel production rises, so does the supply of low-value glycerol by-products, creating an opportunity for cleaner, renewable chemical manufacturing.

In the new study, Manchester engineers, including Dr. Carmine D'Agostino, compared a conventional packed-bed reactor with an intensified membrane-assisted system. By feeding oxygen gradually through a porous ceramic membrane, the team achieved better control of the reaction and suppressed unwanted combustion pathways. The paper is published in the Chemical Engineering Journal.

Under optimized conditions, the membrane reactor delivered up to 58.7% acrylic-acid selectivity—a 10% improvement over standard reactor technology. It also helped regulate temperature, reducing hot-spots and improving reaction stability.

"Our membrane reactor concept shows clear advantages for selective oxidation systems. By distributing oxygen gradually along the reactor, we avoid the formation of hot spots and suppress over-oxidation pathways, which ultimately boosts acrylic-acid selectivity. This is a promising step toward a scalable, lower-emissions alternative to the fossil-based acrylic-acid industry," said Dr. D'Agostino, Senior Lecturer in Chemical Engineering.

Schematic of experimental setup (left) and the rig (right). Credit: Chemical Engineering Journal (2026). DOI: 10.1016/j.cej.2026.175331

A more sustainable route for a globally important chemical

Glycerol is produced in large quantities by the biodiesel sector as a major by-product, with global production growing rapidly over the last two decades. Its oversupply has depressed market prices and created a need for new valorization routes. Converting this low-value by-product into acrylic acid offers a way to lower emissions, reduce reliance on fossil resources and increase the circularity of chemical manufacturing.

The researchers used two catalysts, one to add oxygen in the right way, and one to remove water molecules (orthorhombic Mo–V–O (Ortho-MoVO) oxidation catalysts and HZSM-5(200) dehydration catalysts) respectively, to enable high glycerol conversion (94–99%) across all tested conditions, while the membrane reactor design strategically minimized over-oxidation to CO/CO₂ (COₓ).

The team applied a statistical Design of Experiments (DoE) approach to map the coupled effects of temperature, GHSV, oxygen-to-glycerol ratio and feed-to-membrane ratio. This enabled the identification of precise operating windows that maximize acrylic acid yield while maintaining high conversion and limiting COₓ formation.

A 44-hour stability study highlighted that catalyst deactivation is primarily driven by coke deposition on HZSM-5(200), suggesting future work should focus on developing more coke-resistant materials or regeneration strategies. Ortho-MoVO, by contrast, retained its structure and showed minimal deactivation.

"Waste glycerol represents an abundant and under-used renewable feedstock. Demonstrating that a membrane-assisted reactor can outperform conventional designs at scale is an important milestone for making this conversion route commercially attractive," said Prashant Pawanipagar, Ph.D. Researcher.

Pathway to industrial implementation

The results demonstrate strong potential for integrating membrane-assisted reactors into future commercial glycerol-to-acrylic-acid processes. Beyond enhanced selectivity, the reactor design:

• reduces oxygen consumption,
• improves temperature control,
• may reduce downstream purification costs due to higher product yields, and
• provides a more sustainable alternative to propylene-based production.

The researchers note that next-generation membranes specifically engineered for selective oxygen transport could unlock even greater performance improvements, along with opportunities to optimize operating pressure and reactor compactness. 

Provided by University of Manchester   

by Enna Bartlett, University of Manchester

edited by Gaby Clark, reviewed by Robert Egan 

Source: Engineers boost sustainable acrylic acid production using next‑generation membrane reactor