Ayuni Fitriyaningsih, Witri Wahyu Lestari, Wirawan Ciptonugroho, Fauziyah Azhari, Ubed Sonai Fahruddin Arrozi, Yudha Prawira Budiman, Vito Bintang Saputra
γ-Valerolactone (GVL) is a promising molecule derived from biomass with applications in biofuels, monomer precursors, and green solvents. This study investigates the transfer hydrogenation of ethyl levulinate (EL) to GVL over Ni(II)-modified UiO-67(Zr) catalyst. UiO-67(Zr) was synthesized via a solvothermal method, and Ni(II) was introduced onto the MOF using wet impregnation with metal loadings of 3.0, 5.0, and 10.0 wt%. XRD and IR absorption spectroscopy confirm the development of UiO-67(Zr) and Ni(II)/UiO-67(Zr). Band broadening (in IR spectra) at 769, 654, and 445 cm−1 for UiO-67, suggests the formation of Zr[sbnd]O bonds. The presence of Ni(II) is corroborated by the visual inspection revealing a green color of the modified MOF and further confirmed by FESEM-EDX mapping. Thermogravimetric-analysis reveals that the catalysts exhibit thermal stability up to 450 °C. Nitrogen sorption isotherms indicate a reduction in surface area upon the incorporation of Ni(II). The catalytic transfer hydrogenation (CTH) reaction was carried out in an autoclave under 5 bar N2 pressure, 180 °C for 3h with variation of substrate ratio and catalyst loading. In the absence of a catalyst, no EL conversion or GVL formation occurs. The introduction of 5 wt% catalyst achieves 31% EL conversion with 76% GVL selectivity, highlighting the catalyst's crucial role in transfer hydrogenation. Under optimized conditions (20 wt% catalyst, 1:7 EL/i-PrOH ratio), 88% EL conversion and 88% GVL selectivity are achieved. The addition of Ni(II) enhances GVL selectivity to 97%, albeit with lower conversion. Stability tests show slightly increased conversion and maintained selectivity after three recycling cycles. Increasing the catalyst loading from 5 to 20 wt% (relative to EL) significantly enhances EL conversion and GVL selectivity, improving from 31% and 76% to 88% and 88%, respectively. In spite of lowered conversion to 33%, 97% GVL selectivity can be achieved after enriching Ni(II) content to 10 wt%. Interestingly, both catalysts show slightly improved conversion with maintained selectivity after being recycled 3 times. © 2025 Elsevier B.V.
Chemistry Department, Faculty of Mathematics and Natural Sciences, Universitas Sebelas Maret, Jl. Ir. Sutami No. 36A. Kentingan-Jebres Surakarta, Central Java, 57126, Indonesia; Department of Chemistry Education, Faculty of Teacher Training and Education, Universitas Sebelas Maret, Jl. Ir. Sutami No. 36A. Jebres Surakarta, Central Java, 57126, Indonesia; Chemistry Department, Faculty of Mathematics and Natural Sciences, State University of Malang, Jl. Semarang 5, East Java, Malang, 65145, Indonesia; Chemistry Department, Faculty of Mathematics and Natural Science, Universitas Padjadjaran, Sumedang, 45363, Indonesia
