Intensifying Cyclopentanone Synthesis from Furfural Using Supported Copper Catalysts

Abstract

This work addresses catalytic strategies to intensify the synthesis of cyclopentanone, a bio-based platform chemical and a potential SAF precursor, via Cu-catalyzed furfural hydrogenation in aqueous media. When performed in a single step, using either uniform or staged catalytic bed configuration, high temperature and hydrogen pressures (180 °C and 38 bar) are necessary for maximum CPO yields (37 and 49 %, respectively). Parallel furanic ring hydrogenation of furfural and polymerisation of intermediates, namely furfuryl alcohol (FFA), limit CPO yields. Employing a two step configuration with optimal catalyst bed can curb this limitation. First, the furanic ring hydrogenation can be suppressed by using milder conditions (i. e., 150 °C and 7 bar, and 14 seconds of residence time). Second, FFA hydrogenation using tandem catalysis, i. e., a mix of β-zeolite and Cu/ZrO₂, at 180 °C, 38 bar and 0.6, allows sufficient time for CPO formation and minimises polymerisation of FFA, thereby resulting in 60 % CPO yield. Therefore, this work recommends a split strategy to produce CPO from furfural. Such modularity may aid in addressing flexible market needs.

Keywords: Copper catalysis; Cyclopentanone; Furfural; Hydrogenation; Polymerization.

Figure 1

Reaction scheme for hydrogenation of furfural to CPO as collated from literature. The green box indicates the preferred reaction network of furfural hydrogenation to cyclopentanone.

Figure 2

NH₃‐TPD of the different supported‐Cu catalysts.

Figure 3

Comparison of different supports on furfural hydrogenation to cyclopentanone using 1 wt.% furfural in water. Conditions: T=150–180 °C; P_total=12 bar; W_cat=1 gram; W_SiC=3 gram; Q_feed=0.1 mL min⁻¹, Q_H2=5 NmL min⁻¹; and WHSV=$0.06{\mathrm{g}}_{\mathrm{furfural}}{\mathrm{g}}_{\mathrm{cat}}^{-1}{\mathrm{hr}}^{-1}$ .

Figure 4

Effect of pressure on FFA hydrogenation to CPO using 1 wt.% FFA in water. Conditions: T=150 °C; W_cat=0.2 grams of Cu/ZrO₂ and β‐zeolite each; W_SiC=3.6 grams; Q_feed=0.2 mL min⁻¹; ${\mathrm{Q}}_{{\mathrm{H}}_2}$ =4 NmL min⁻¹, WHSV=0.6 ${\mathrm{g}}_{\mathrm{FFA}}{\mathrm{g}}_{\mathrm{cat}}^{-1}{\mathrm{h}}^{-1}$ .

Figure 5

Effect of temperature on FFA hydrogenation to CPO using 1 wt.% FFA in water. Conditions: T=150–200 °C; P_total=48 bar; W_cat=0.2 grams of Cu/ZrO₂ and β‐zeolite each; W_SiC=3.6 grams; Q_feed=0.2 mL min⁻¹, ${\mathrm{Q}}_{{\mathrm{H}}_2}$ =4 N, WHSV=0.6 ${\mathrm{g}}_{\mathrm{FFA}}{\mathrm{g}}_{\mathrm{cat}}^{-1}{\mathrm{h}}^{-1}$ . Figures within the green bar indicate CPO yield.

Figure 6

Furfural hydrogenation to CPO using 1 wt.% furfural in water. The three stacked bars on the left‐hand side represent mixed Cu/ZrO₂ and β‐zeolite bed while those on right‐hand side represent commercial Cu/ZnO‐Al₂O₃ before the mixed bed. Conditions: Temperature and pressure are indicated on the X‐axis. W_cat=indicated on the graph; Q_feed=0.2 mL min⁻¹, ${\mathrm{Q}}_{{\mathrm{H}}_2}$ =4 N, WHSV=0.06 and 0.4 ${\mathrm{g}}_{\mathrm{furfural}}{\mathrm{g}}_{\mathrm{cat}}^{-1}{\mathrm{hr}}^{-1}$ for mixed and sequential bed, respectively. (a :Q_feed=0.15, ${\mathrm{Q}}_{{\mathrm{H}}_2}$ =3 NmL min⁻¹, b: Q_feed=0.4, ${\mathrm{Q}}_{{\mathrm{H}}_2}$ =8 NmL min⁻¹). Figures in the green bar indicate CPO yield for respective temperature.

Figure 7

FFA hydrogenation to CPO using 1 wt.% FFA in water. Conditions: T=180 °C; P_total=48 bar; W_cat=0.2 grams of Cu/ZrO₂ and β‐zeolite each; W_SiC=3.6 grams; Q_feed=0.2 mL min⁻¹, ${\mathrm{Q}}_{{\mathrm{H}}_2}$ =4 NmL min⁻¹, WHSV=0.6 ${\mathrm{g}}_{\mathrm{FFA}}{\mathrm{g}}_{\mathrm{cat}}^{-1}{\mathrm{h}}^{-1}$ .

Figure 8

XRD pattern of fresh vs. spent catalyst. Inset on the top right‐hand side shows an enlarged segment of XRD pattern in Cu⁰(111) region while the TEM images of fresh and spent catalysts are shown on the top left‐hand side.