Heterogeneous Iron Catalyst Fe/SBA-15 towards sp3 C-O bond activation in the absence of base and additive

A heterogeneous iron-catalyzed (8wt%Fe/SBA-15) mediated direct alkylation of benzyl alcohol with aryl boronic acid in the absence of base and additive via C-O bond activation is demonstrated. This catalyst system led to an efficient Friedel-crafts alkylation reaction. The acidic site in the catalyst system had been confirmed by NH3-TPD, which shows the presence of three different acidic sites viz., weak, moderated, and strong acid sites. The catalyst showed five times recyclable ability.

Heterogeneous Iron Catalyst Fe/SBA-15 towards sp3 C-O bond activation in the absence of base and additive

A heterogeneous iron-catalyzed (8wt%Fe/SBA-15) mediated direct alkylation of benzyl alcohol with aryl boronic acid in the absence of base and additive via C-O bond activation is demonstrated. This catalyst system led to an efficient Friedel-crafts alkylation reaction. The acidic site in the catalyst system had been confirmed by NH3-TPD, which shows the presence of three different acidic sites viz., weak, moderated, and strong acid sites. The catalyst showed five times recyclable ability.

Selective 5-Hydroxymethylfurfural Hydrogenolysis to 2,5-Dimethylfuran over Bimetallic Pt-FeOx/AC Catalysts

The selective hydrogenolysis of 5-hydroxymethylfurfural (HMF) platform molecule to 2,5-dimethylfuran (DMF) has attracted increasing attention due to its broad range of applications. However, HMF, with multiple functional groups, produces various byproducts, hindering its use on an industrial scale. Herein, a bimetallic Pt-FeOx/AC catalyst with low Pt and FeOx loadings for selective HMF hydrogenolysis to DMF was prepared by incipient wetness impregnation. The structures and properties of different catalysts were characterized by XRD, XPS, TEM, ICP-OES and Py-FTIR techniques. The addition of FeOx enhanced Pt dispersion and the Lewis acidic site density of the catalysts, and was found to be able to inhibit C=C hydrogenation, thereby im-proving DMF yield. Moreover, the presence of Pt promoted the reduction of iron oxide, creating a strong interaction between Pt and FeOx. This synergistic effect originated from the activation of the C–O bond over FeOx species followed by hydrogenolysis over the adjacent Pt, and played a critical role in hydrogenolysis of HMF to DMF, achieving a yield of 91% under optimal reaction conditions. However, the leaching of Fe species caused a metal–acid imbalance, which led to an increase in ring hydrogenation products.

Single Adsorption of Diclofenac and Ronidazole from Aqueous Solution on Commercial Activated Carbons: Effect of Chemical and Textural Properties

The importance of the textural and physicochemical characteristics upon the adsorption capacity of the commercial activated carbons (ACs) Coconut, Wood, Merck, Darco and Norit towards ronidazole (RNZ) and diclofenac (DCF) from water solution was investigated thoroughly in this work. At pH = 7, Coconut AC and Wood AC presented the highest adsorption capacity towards RNZ (444 mg/g) and DCF (405 mg/g), correspondingly. The maximum mass of RNZ adsorbed onto Coconut AC was higher in this study than those outlined previously in other works. Besides, the maximum capacity of Wood AC for adsorbing DCF was comparable to those found for other ACs. The findings disclosed that the adsorption capacity of all the ACs was remarkably increased by surface area and was favored by incrementing the acidic site concentration. The π-π stacking interactions were the predominant adsorption mechanism for the RNZ and DCF adsorption on ACs, and the acidic sites favored the adsorption capacity by activating the π-π stacking. Electrostatic interactions did not influence the adsorption of RNZ on Coconut AC, but electrostatic repulsion decreased that of DCF on Wood AC. In the range of 15–25°C, the adsorption of RNZ and DCF on the Coconut and Wood ACs was endothermic, but the capacity remained essentially constant by elevating the temperature from 25 to 35°C.

Hydrogenation of pentenal over supported Pt nanoparticles: influence of Lewis-acid sites in the conversion pathway

The superb TOF and high selectivity of Pt/CeAl are associated with the surface properties (e.g. medium Lewis acidic site). The unsaturated Ce4+/Al3+ cations pairs act as the acid sites and electron acceptors to polarize the CO bonds.

Response of Drainage Water Quality to Fertilizer Applications on a Switchgrass Intercropped Coastal Pine Forest

The objectives of this study were (1) to test the hypothesis that fertilizer applications do not increase nutrient fluxes on a switchgrass/pine forest (IC) when compared to a mature pine forest (MP) and (2) to evaluate post-fertilization (post-fert, 2014–2016) fluxes of nitrogen (N) and phosphorus (P) on IC and compare them to those observed during switchgrass growth prior to fertilization (pre-fert, 2012–2014) and site preparation for switchgrass establishment (site prep, 2009–2012). Nitrogen and P were applied to IC, a paired pure switchgrass site (SG), and MP, each about 25 ha in size, in June 2014, and again in June 2015 for the IC and SG sites only. Nitrogen and P concentrations were measured biweekly and rainfall and drainage outflow were measured continuously. During post-fert, the mean N concentrations and total loads were lower (p < 0.05) in IC than in SG and MP. The mean NO3-N concentration and loads in IC were lower during post-fert than during site prep. The post-fert phosphate concentrations in IC were lower than they were during pre-fert and site prep. Frequent N and P applications in IC did not significantly (α = 0.05) increase N and P fluxes, likely due to plant uptake and sorption on the acidic site.

A green approach for the preparation of a surfactant embedded sulfonated carbon catalyst towards glycerol acetalization reactions

A surfactant embedded carbon-based acid catalyst was prepared via simple physical mixing and thermal treatment to establish the relationship between hydrophobicity and acidic site density for efficient glycerol acetalization reaction.

Methanol loading dependent methoxylation in zeolite H-ZSM-5

Room temperature methoxylation is methanol loading dependent: the higher the methanol loading, the faster the methoxylation. Methanol load of ≥2 leads to methoxylation while no methoxylation is observed with ≤1 molecule per Brønsted acidic site.

Integration of metalloporphyrin into cationic covalent triazine frameworks for the synergistically enhanced chemical fixation of CO2

Cobalt porphyrin as a Lewis acidic site was integrated into imidazolium-functionalized porous cationic covalent triazine frameworks for the cooperatively enhanced catalysis CO2 cycloaddition to produce cyclic carbonates.