Effect of lanthanum on catalytic performance of Ru/Al2O3 catalyst for hydrogenation of esters to corresponding alcohols

Abstract

Ru-La/γ-Al 2 O 3 catalyst was prepared by impregnation method and characterized by temperature programmed reduction(TPR), transmission electron microscopy(TEM), X-ray photoelectron spectra(XPS), BrunauerEmmett-Teller(BET), X-ray diffraction(XRD), and NH 3 -temperature programmed desorption(NH 3 -TPD). NH 3 -TPD revealed that the strong acidic centers in γ-Al 2 O 3 are not the major factor to cause the hydrolysis of esters to acids in the hydrogenation of esters. The results of TPR and TEM indicate that the appropriately added lanthanum results in the good dispersion of ruthenium and the easy reduction of ruthenium oxide on Ru-La/γ-Al 2 O 3 , which could promote the catalytic activity of Ru-La/γ-Al 2 O 3 for the hydrogenation of methyl propionate to propanol. When the amount of lanthanum added in the catalyst was up to 9%(mass fraction), 4%Ru-9%La/γ-Al 2 O 3 catalyst gave a conversion of methyl propionate of 98.1% and a selectivity of 94.8% to propanol at a reaction temperature of 180 °C and a hydrogen pressure of 5.0 MPa.

Polymeric Ruthenium Porphyrin-Functionalized Carbon Nanotubes and Graphene for Levulinic Ester Transformations into γ-Valerolactone and Pyrrolidone Derivatives

“…7−9 Various Ru-based catalysts have been reported for the hydrogenation of LA and levulinic ester to GVL, including homogeneous catalysts of RuCl 3 − PPh 3 , 10 Ru(acac) 3 −PBu 3 (acac, acetylacetonate), 11 Ru(acac) 3 − P(n-oct) 3 , 12 Ru(acac) 3 −TPPTS [TPPTS, tris(3-sulfophenyl)phosphine trisodium salt], 13 and Shvo catalyst, 14 heterogeneous catalysts of Ru/C, 15−20 Ru/MOFs (metal−organic frameworks), 21 Ru/TiO 2 , 22,23 Ru/SiO 2 , 24 Ru/Beta-12.5 (DeAl-Hbeta), 25 Ru/hydroxyapatite 26 Ru 3 (CO) 12 -derived Ru nanoparticles (NPs), 27 Ru/SBA-SO 3 H (sulfonic acid-functionalized mesoporous silica), 28 and Ru/SPES (sulfonated polyethersulfone), 29 and bimetallic catalysts of Ru−Re/C, 30,31 Ru−Sn/ C, 32,33 Ru−Ni/Meso-C, 34 Ru−Pd/TiO 2 , 35 and Ru−La/ Al 2 O 3 . 36 Ru-based homogeneous catalysts generally showed outstanding catalytic performance for GVL synthesis; however, toxic and air-and moisture-sensitive phosphorus ligands were applied in the hydrogenation reactions. 37 Therefore, inspired by nature, multidentate nitrogen ligands such as porphyrins should be an excellent candidate to promote the catalytic reactions under phosphane-free conditions.…”

“…GVL is generally prepared by the hydrogenation of cellulose-derived levulinic acid (LA) with homogeneous or heterogeneous catalysts, and ruthenium (Ru) catalysts generally exhibit excellent activity and selectivity. − Various Ru-based catalysts have been reported for the hydrogenation of LA and levulinic ester to GVL, including homogeneous catalysts of RuCl 3 –PPh 3 , Ru­(acac) 3 –PBu 3 (acac, acetylacetonate), Ru­(acac) 3 –P­( n -oct) 3 , Ru­(acac) 3 –TPPTS [TPPTS, tris­(3-sulfophenyl)­phosphine trisodium salt], and Shvo catalyst, heterogeneous catalysts of Ru/C, − Ru/MOFs (metal–organic frameworks), Ru/TiO 2 , , Ru/SiO 2 , Ru/Beta-12.5 (DeAl-H-beta), Ru/hydroxyapatite Ru 3 (CO) 12 -derived Ru nanoparticles (NPs), Ru/SBA-SO 3 H (sulfonic acid-functionalized mesoporous silica), and Ru/SPES (sulfonated polyethersulfone), and bimetallic catalysts of Ru–Re/C, , Ru–Sn/C, , Ru–Ni/Meso-C, Ru–Pd/TiO 2 , and Ru–La/Al 2 O 3 …”