Enhancing Phenol Adsorption on Hydrophobic Pd/SiO2 to Achieve Faster and More Selective Hydrogenation

• Published in: Topics in catalysis Vol. 66; no. 15-16; pp. 1143 - 1151
• Main Authors: Chalmers, Jason A., Moon, Hyunjin, Ausman, Samantha F., Chuang, Cheng-Hsun, Scott, Susannah L.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.09.2023; Springer Nature B.V; Springer
• Subjects: Adsorption; Aqueous solutions; Catalysis; Catalysts; Characterization and Evaluation of Materials; Chemical synthesis; Chemistry; Chemistry and Materials Science; Cyclohexanone; Hydrogenation; Hydrophobicity; Industrial Chemistry/Chemical Engineering; NMR; Nuclear magnetic resonance; Original Paper; Pharmacy; Physical Chemistry; Room temperature; Silicon dioxide; Cyclohexanone selectivity; Microkinetic modelling; Phenol hydrogenation; Catalyst hydrophobicity
• ISSN: 1022-5528; 1572-9028
• DOI: 10.1007/s11244-023-01851-2

The effect of catalyst hydrophobicity on the kinetics of hydrogenation of aqueous phenol was investigated. The hydrophobicity of a Pd/SBA-15 catalyst was altered by synthesizing an organosilane with biphenylene framework linkers. Partitioning of phenol between the aqueous solution and the pores favors the hydrophobic catalyst by an order of magnitude at room temperature, relative to the hydrophilic catalyst. The rate of hydrogenation at 75 °C is higher in the hydrophobic catalyst, as is the selectivity for the partial hydrogenation product, cyclohexanone. Analysis of kinetic profiles measured using operando  13 C NMR reveals that the hydrophobic catalyst has a larger apparent (i.e., composite) adsorption constant for phenol, which results in higher phenol surface coverage and, consequently, faster and more selective hydrogenation to cyclohexanone.