Polyoxomolybdates catalysed cascade conversions of cellulose to glycolic acid with molecular oxygen via selective aldohexoses pathways (an epimerization and a [2+4] Retro-aldol reaction)
-
Add time:07/18/2019 Source:sciencedirect.com
Selective cascade conversion of cellulose into valuable C2 or C4 products over acid catalysts is still not fully explored because glucose-fructose isomerization followed by fructose conversions is thermodynamically easy to occur during the reaction, leading the formation of C6, C5, C3 and C1 products such as 5-hydroxymethylfurfural (HMF), levulinates, lactates, formates, and so on. In this study, phosphomolybdates (PMo) with the Keggin structure was found to promote cascade oxidation of cellulose conversion via selective aldohexoses pathways, i.e. an epimerization and a [2 + 4] retro-aldol of glucose/mannose, rather than aldo-ketohexoses routes, i.e. a glucose-fructose isomerization and a [3 + 3] retro-aldol of fructose, which produced glycolic acid (GlycA) (C2) as the main product (∼50% selectivity). Either in aerobic or anaerobic state, PMo selectively catalyzed glucose epimerization into mannose at <100 °C (∼95% selectivity) and effectively promoted the [2 + 4] retro-aldol reaction of these aldohexoses at >100 °C. This behavior is completely different from that of molybdate in MoO3 which is only effective for the epimerization reaction (the Bilik reaction). In this cascade oxidation reaction, PMo was reduced into heteropoly-blue (PMored) as observed by the color change of the solution, UV-VIS and FT-IR measurements. In this case, the molecular oxygen was found to reoxidize PMored into PMo, leading the catalytic activity to be remained stable. The results shown in this study provide an insight for the catalyst development on selective synthesis of C2, C4 and/or other novel valuable chemicals from carbohydrates via the aldohexose pathways.
We also recommend Trading Suppliers and Manufacturers of 12-MOLYBDOSILICIC ACID HYDRATE (cas 11089-20-6). Pls Click Website Link as below: cas 11089-20-6 suppliers
Prev:Structure and catalytic properties of silica-supported polyoxomolybdates III. 12-molybdosilicic acid catalysts: vibrational study of the dispersion effect and nature of the mo species in interaction with the silica support
Next:Depolymerization of polysilicic acid by tiron) - 【Back】【Close 】【Print】【Add to favorite 】
- Related Information
- Enthalpies of formation and DSC and TG results of heteropoly acids containing tungsten and molybdenum07/25/2019
- Geochemical behaviour of a bentonite barrier in the laboratory after up to 8 years of heating and hydration07/24/2019
- Efficient homogeneous catalysis of heteropoly acid and its characterization through etherifications of alcohol07/23/2019
- Synthesis of diethylene glycol ethyl ether with diethylene glycol and ethanol by the catalysis of heteropoly acid07/22/2019
- Polypyrrole linear actuation tuned by phosphotungstic acid07/20/2019
- A facile one-pot synthesis of thioethers using heteropoly acids07/21/2019
- Depolymerization of polysilicic acid by tiron07/19/2019
- Structure and catalytic properties of silica-supported polyoxomolybdates III. 12-molybdosilicic acid catalysts: vibrational study of the dispersion effect and nature of the mo species in interaction with the silica support07/17/2019
- Electrochemical study of isopoly- and heteropoly-oxometallates film modified microelectrodes —vi. preparation and redox properties of 12-molybdophosphoric acid and 12-molybdosilicic acid modified carbon fiber microelectrodes07/16/2019
-
Health and Chemical more >