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• CoMg/Al 2 O 3 was synthesized by the wetness impregnation method. • IGC was used to study the surface properties of CoMg/Al 2 O 3. • Dispersive and specific components are enhanced after Co and Mg impregnation. • CoMg/Al 2 O 3 presents high activity in aerobic oxidation of p -cresol into p -HBA. • Medium adsorption of p -cresol and strong stabilization of intermediates are involved. The surface properties of CoMg/Al 2 O 3 were evaluated in the aerobic oxidation of p -cresol. The surface interaction is enhanced greatly after Co and Mg impregnation with the mole ratio of Co/Mg from 2 : 1 and 2 : 3. The strongest interaction for the nonpolarity and benzene ring was found on CoMg/Al 2 O 3 with Co/Mg of 2 : 3. But for the interaction with p -π group bonding with negative anion, the highest value appears on the catalyst with the Co/Mg of 2 : 2. In aerobic oxidation of p -cresol, the conversion is significantly increased with Co addition and reaches around 60 % after 24 h' reaction at 338 K. The highest selectivity of p -hydroxybenzaldehyde of 99 % is achieved on Al 2 O 3 with the co-impregnation mole ratio of Co/Mg of 2 : 2. It is suggested that medium adsorption of the reactants and strong stabilization of the intermediates facilitate the aerobic oxidation of p -cresol to p -hydroxybenzaldehyde. [Display omitted] [ABSTRACT FROM AUTHOR]

Commercial fillers are widely used in the industrial manufacturing of silicone-based sealants such as CaCO 3 filled polydimethylsiloxane (PDMS). The surface property of calcium carbonate, which is readily influenced by the adsorbed water and chemical modifiers, results in different rheological performances of the composites. However, it is difficult to characterize the surface due to the multiple contributions from the morphology, functional groups, and pore structure. In this work, the surface property was differentiated by the surface energies using inverse gas chromatography (IGC). The dispersive interaction was determined by n -alkanes (C 7 -C 10), and the specific components were evaluated by cyclohexane, benzene, trichloroethylene, and tetrachloroethylene. The calcium carbonates showed the different dispersive interaction and the varied specific component on the modified surface. It was suggested that the dispersive interaction between calcium carbonate fillers and PDMS impacted the viscosity of the formed composite. [Display omitted] • Similar structure and morphology for the commercial CaCO 3 fillers. • Different DOP absorption of the fillers and varied rheology for the filled PDMS. • IGC was used to study the surface property of the modified CaCO 3. • Varied dispersive and specific components of surface energy for CaCO 3 fillers. • Strong dispersive interaction promotes the interface interaction of the composites. [ABSTRACT FROM AUTHOR]