Unprecedented selectivities in aldol condensation over Mg–Al hydrotalcite in a fixed bed reactor setup

• Aldol condensation was successful over hydrotalcites in continuous setup.
• Formation of heavier aldol condensation products was established.
• Heavy aldol condensation products of furfural and acetone were identified.

Aldol condensation of furfural with acetone (molar ratio 1:10) was carried out in a flow fixed bed setup at 50 °C using calcined hydrotalcite with Mg/Al of 3 as a catalyst. Complete conversion of furfural and stable catalyst performance was obtained during the initial 50 h on stream. This period was followed by a rapid catalyst deactivation. In contrast to previous reports, higher molecular weight products that were identified as products of successive aldol condensation of acetone with furfural were observed. Their concentration was time-dependent with a maximum formation after 10 to 30 h on stream.

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