No abstract

No abstract

Designing and developing non-noble metal-based heterogeneous catalysts have a substantial importance in biomass conversion. Meerwein-Ponndorf-Verley (MPV) reaction is a significant pathway for eco-friendly catalytic transfer hydrogenation (CTH) of biomass derived furfural into furfuryl alcohol. In this work, a series of copper-supported hydroxyapatite (HAp) catalysts with different copper loadings (2–20 wt.%) were prepared by a facile impregnation method and tested in the reduction of furfural to furfuryl alcohol using 2-propanol as a hydrogen donor. The structural and chemical properties of the synthesised catalysts were analysed by using various techniques (XRD, N2 sorption, SEM, TEM, UV-DRS, ICP, FTIR, TPR, TPD-CO2 and N2O titration). The effect of copper loading was found to be significant on the total performance of the catalysts. The results demonstrate that 5CuHAp catalyst possess highly dispersed copper particles and high basicity compared to all other catalysts. Overall, 5CuHAp exhibited highest conversion (96%) and selectivity (100%) at 140 °C at 4 h time on stream. The optimised reaction conditions were also determined to gain the high activity.

A series of Magnesium hydrogen phosphate (MgHP) catalysts with different magnesium to phosphorous (Mg/P) mole ratios at varying calcination temperatures has been synthesised, bearing in mind the effectiveness as well as the stability of MgHP to catalyse acrylic acid (AA) production from biorenewable lactic acid (LA), a synthetic process applicable to biomass conversion. The physicochemical properties of the MgHP catalysts have been thoroughly characterised and the formation of Mg(NH4)PO4, MgHPO4 and Mg2P2O7 with different structural and acidic properties have been reported. The high catalytic performance of MgHP catalysts with high AA yields (100% conversion and 85% selectivity) at high space velocities (WHSVLA = 3.13 h−1) have been achieved at 360 °C. NH3-Temperature programmed desorption (TPD) and pyridine FTIR have shown that the effectiveness of a catalyst is accounted for not primarily by the actual strength of acidic sites, but is due to the presence of Lewis acidic sites compared to Bronsted sites.

In this work, biomass-based platform molecule lactic acid conversion to acrylic acid has been studied. A series of Lanthanum phosphate (LaP) catalysts prepared by varying the lanthanum to phosphorus (La/P) mole ratio (i.e. 0.2, 0.35, 0.5, 1.0 and 2.0) and also prepared at different calcination temperatures (i.e. 400, 500, 600 and 800 ºC) were investigated. The prepared catalysts were characterised by using different techniques and tested in the dehydration of lactic acid (LA) to acrylic acid (AA) production. All the synthesized catalysts were characterized to understand the physico-chemical properties such as degree of crystallinity, total surface acidity, specific surface area and morphology were analysed. The NH 3 -TPD results imply that, all the catalysts exhibited varied amount of total acidity, mostly weak acid sites, with the phosphate loading. The weak acid sites which are mainly Lewis acid sites played an important role in producing AA selectively and efficiently from the LA conversion. The most optimized reaction conditions were determined to obtain highest LA conversion, selectivity, and AA yield. The catalyst with La/P mole ratio 0.35 and calcined at 500 ºC, exhibited best performance with complete LA conversion, AA selectivity of ~74% and a maximum yield of AA~74% was achieved. Furthermore, the LaP(0.35)[500] catalyst was successfully tested for three different time on streams and found to be stable.