Economic and environmental comparison of mainstream and potential alternative routes: a study on one-step and two-step processes for methacrylonitrile production via isobutene ammoxidation

Abstract

Methacrylonitrile is an indispensable chemical intermediate in aerospace and wind energy material manufacturing. Currently, the one-step isobutene ammoxidation process is the industrial mainstream for its production, but its drawbacks of high reaction temperature, many by-products and high purification energy consumption have prompted researchers to explore alternatives. Although the two-step ammoxidation process has theoretical advantages, it is still in the experimental stage, with its economic and environmental benefits not systematically evaluated. Under unified conditions (99.5% product purity, 1 t∙h^–1 isobutene feed), this study compared the two processes via techno-economic analysis and life cycle assessment. Results show the two-step process has a higher yield (82.4% vs. 77.3%), while the one-step process is superior in unit cost (1.90\text{vs}.2.23\text{ USD}\cdot {\text{kg}}_{{\text{MAN}}^{\text{-1}}}) and life cycle carbon emissions (7.42\text{vs}.9.10{\text{t}}_{{\text{CO2}}_{\text{-eq}}}\cdot {\text{t}}_{{\text{MAN}}^{\text{-1}}}. Sensitivity analysis indicates yield is key to the two-step process’s competitiveness: each 1% increase reduces cost by 0.07\text{USD}\cdot {\text{kg}}_{{\text{MAN}}^{\text{-1}}} and emissions by 0.37{\text{ t}}_{{\text{CO2}}_{\text{-eq}}}\cdot {\text{t}}_{{\text{MAN}}^{\text{-1}}}, and 86.9% yield makes it comparable to the one-step process. Thus, improving yield to over 86.9% via catalyst modification is critical for its industrialization, providing quantitative targets for optimization and a scientific basis for process selection and sustainability assessment.

Keywords

methacrylonitrile / isobutene ammoxidation / process simulation / techno-economic analysis / life cycle assessment

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Higher Education Press 2026

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