Oxidative esterification of acetol with methanol to methyl pyruvate over hydroxyapatite supported gold catalyst: Essential roles of acid-base properties

Hydrazine as Facile Nitrogen Source for Direct Synthesis of Amines over a Supported Pt Catalyst

“…Other inorganic material supported Pt catalysts, such as Pt/MgO, Pt/Al 2 O 3 , Pt/ZnO, Pt/ZrO 2 , Pt/SiO 2 , Pt/Nb 2 O 5 , and Pt/HAP, with a range of Pt particle sizes of 2.0–3.6 nm, showed good conversion for 1a in most cases; however, lower selectivity for 3a was obtained. Specifically, when using MgO as the support, which possesses basic properties, the main products were azine 5a (28%), N-substituted hydrazone 6a (24%), hydrazone 8a (5%), and primary amine 7a (27%) (Table , entry 4). This result indicated that the Pt/MgO had a high activity for the dehydrogenation of alcohol but poor activities for the hydrogenation of azine-related compounds to break N–N bonds and further transformations to secondary amine.…”

“…This result indicated that the Pt/MgO had a high activity for the dehydrogenation of alcohol but poor activities for the hydrogenation of azine-related compounds to break N–N bonds and further transformations to secondary amine. In the cases of using Al 2 O 3 , ZrO 2 , SiO 2 , and HAP as the supports, which possess acidic or amphoteric properties, , the main products were overalkylated tertiary amine 10a and/or deoxygenated methylbenzene 9a (Table , entries 5, 7, 8, and 10). These results implied that Pt/Al 2 O 3 , Pt/ZrO 2 , Pt/SiO 2 , and Pt/HAP gave impressive activities for the dehydrogenation of alcohol; however, the overalkylation and/or hydro-deoxygenation were too striking to result in a poor selectivity for the target secondary amine.…”

Development of Au and 1D Hydroxyapatite Nanohybrids Supported on 2D Boron Nitride Sheets as Highly Efficient Catalysts for Dehydrogenating Glycerol to Lactic Acid

“…Acid site density was about 3.27 μmol/g, while the base site density accounted for 3.02 μmol/g. 38,39,49 The mildly higher acidic nature of the catalyst presented a favorable platform for conversion of glycerol to LA. Especially, the geometrical surface charges of HAp provided the acid−base reaction sites for the oxidation of glycerol as well as a higher affinity toward glycerol adsorption.…”

“…Further, Bruker Vertex 80v FT-IR (wavenumber range- 450 to 4500 cm –1 ), Witec Alpha 300 Raman spectrometer (laser wavelength, 532 nm), and X-ray photoelectron spectroscopy (XPS, ESCALab MKII) were used to determine the structural and chemical compositions of the samples. Moreover, acid base strength of the composite catalyst was measured through CO 2 (for basic sites) and NH 3 (for acidic sites) temperature-programmed desorption studies (TPD) as described elsewhere. , …”

“…Moreover, acid base strength of the composite catalyst was measured through CO 2 (for basic sites) and NH 3 (for acidic sites) temperature-programmed desorption studies (TPD) as described elsewhere. 38,39 Catalytic Tests and Characterizations. Catalyst performances of BN NSs, c-BN NPs (commercial BN nanoparticles received from Sigma-Aldrich), Au/BN, HAp/BN, and Au/HAp/BN nanohybrids were evaluated using the 50 mL inner volume Teflon-lined stainlesssteel autoclave.…”