Synthesis of γ‐Valerolactone from Levulinic Acid and Formic Acid over Mg‐Al Hydrotalcite Like Compound

• Published in: ChemistrySelect (Weinheim) 2018-06, Vol.3 (22), p.6186-6194
• Main Authors: Hussain, SK, Velisoju, Vijay Kumar, Rajan, N. Pethan, Kumar, Balla Putra, Chary, Komandur V. R.
• Format: Article
• Language: English
• Subjects: Formic acid; Hydrogenation; Hydrotalcite; Levulinic acid; γ-Valerolactone
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.201800536

Catalytic transformation of levulinic acid (LA) with in situ hydrogen transfer from formic acid (FA) into γ‐valerolactone (GVL) was investigated over calcined Mg‐Al hydrotalcite catalysts under atmospheric N2 pressure. Several catalysts containing different Mg/Al mole ratio in between 1:4 to 7:1 were synthesized by co‐precipitation method. The catalytic performances of calcined Mg/Al hydrotalcite during LA hydrogenation were found to be much higher than pure magnesia (MgO) and physical mixture samples of MgO‐Al2O3. Pure MgO exhibited higher activity in the initial hours but a gradual deactivation was noticed during the course of reaction time. Under the optimised reaction conditions, the calcined Mg/Al hydrotalcite catalyst with Mg/Al ratio of 3:1 exhibited superior performance with high GVL selectivity of 98% and total conversion of LA till 10 h of reaction time. The synthesised catalysts were characterized by various spectroscopic and adsorption techniques. The catalytic activity results during hydrogenation are well supported by means of the findings of characterization of the catalysts. An efficient, reusable and inexpensive hydrotalcite like mixed‐metal oxide (Mg−Al) is explored for biomass derivable levulinic acid to γ‐valerolactone in vapor phase at an ambient pressure using formic acid as in‐situ hydrogen source. The process optimization has also been carried out for the best performance catalyst i. e. Mg−Al (3:1) with stable activity up to 30 h towards the desired product under the optimized reaction conditions.