Experimental demonstration of an integrated reaction-separation process for the synthesis of 4-methyl-1,3-dioxane in a lab-scale miniplant
Year: 2026
Type: article
Abstract: ABSTRACT Cyclic acetals can be synthesized via catalytic routes, ranging from purely chemocatalytic to concatenated bio-chemo catalytic approaches. The cyclic acetal 4methyl-1,3-dioxane (4-MDX) is synthesized from H₂, CO₂, and 1,3-butanediol, catalyzed by the organometallic complex [Ru(triphos)(tmm)] with Al(OTf) 3 as Lewis acid co-catalyst. As the reaction is equilibrium-limited, in situ product removal of 4-MDX by liquid-liquid extraction mitigates this limitation. We demonstrate this process concept in a lab-scale miniplant for integrated reaction-extraction, elucidating scale-up effects and key requirements for successful piloting. The batch reaction was scaled from 1 mL to 400 mL, followed by continuous catalyst phase operation coupled with n -decane extraction. Remaining volatiles were removed under vacuum between four recycling runs. Batch scale-up maintained 4-MDX selectivity and reduced side-product formation. In continuous operation, selective 4-MDX extraction enabled additional 4-MDX formation beyond batch equilibrium, although the net 4-MDX discharge decreases over time, indicating limitations due to water accumulation or product wash-out. Downstream batch rectification afforded 4-MDX purities up to 99.6 wt.%. Over 114 h time-on-stream, catalyst deactivation remains below 11 %, roughly half the value in the small-scale recycling experiments. Overall, the results demonstrate feasible miniplant piloting for integrated 4-MDX synthesis and identify water management and reaction-extraction time-scale matching as key levers for process intensification.
Institutions: RWTH Aachen University, Forschungszentrum Jülich
Language: English
Subfield: Process Chemistry and Technology
Field: Chemical Engineering
Domain: Physical Sciences
Open Access status: hybrid
Estimated APC paid: $3,910
OpenAlex ID: W7162449292