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Schematic representation of hydrolytic hydrogenation (A) and hydrogenolysis (B) of cellulose to hexitols and glycols, respectively.
Source publication
Conversion of biomass cellulose to value-added chemicals and fuels is one of the most important advances of green chemistry stimulated by needs of industry. Here we discuss modern trends in the development of catalysts for two processes of cellulose conversion: (i) hydrolytic hydrogenation with the formation of hexitols and (ii) hydrogenolysis, lea...
Citations
... Sorbitol yields were in the range of 16.8 to 53.4%, when carbon blacks, activated carbon, Al2O3, ZrO2, or TiO2 supported Pt catalyst were employed (Kobayashi et al. 2011). In systems where acidfunctionalized carbonaceous materials or HZSM-5 served as support, and where Pt, Ru, or Ni served as the active component, the sorbitol yields were in the range of 39.4 to 70.0% (Manaenkov et al. 2019). A sorbitol yield of 91.0% was obtained with CuO/CeO2-ZrO2 (Manaenkov et al. 2019). ...
... In systems where acidfunctionalized carbonaceous materials or HZSM-5 served as support, and where Pt, Ru, or Ni served as the active component, the sorbitol yields were in the range of 39.4 to 70.0% (Manaenkov et al. 2019). A sorbitol yield of 91.0% was obtained with CuO/CeO2-ZrO2 (Manaenkov et al. 2019). Sorbitol could be decreased by dehydrogenation (Deutsch et al. 2012;Jia and Liu 2016), dehydration (Sun et al. 2013), hydrogenolysis (Sun et al. 2015), etc. ...
... The highest 1,2-PG yield was 20.7%, obtained for ZnO/CNT at 270 min. High 1,2-PG yields were obtained in CuCr catalysts (Xiao et al. 2013) and Sn-containing catalysts (Manaenkov et al. 2019); the yields were in the range of 32.2 to 39.0%. The yields of THFDM kept increasing all the time for ZnO/CNT, Nb2O5/CNT, and ZrO2/CNT. ...
The effects of CeO2, ZrO2, Nb2O5, and ZnO catalysts supported on carbon nanotubes (CNT) relative to cellulose hydrothermal hydrogenolysis in the presence of Ni/CNT and pressured H2 was studied in this work. The catalysts were characterized by inductively coupled plasma – optical emission spectrometry, X-ray diffraction, X-ray photoelectron spectrometry, transmission electron microscopy, NH3 temperature programmed desorption (TPD), and CO2-TPD. Glucose and its isomers were detected by mass spectrometry. The results showed that redox active CeO2/CNT with strong Lewis acid and strong Lewis base sites was active in C-C bong cracking, isomerization, dehydrogenation, and hydrodeoxygenation reaction, yielding 36.3% ethylene glycol and 17.2% 1,2-propylene glycol. The ZnO/CNT with Bronsted base accelerated isomerization, retro-aldol condensation, and dehydrogenation, yielding 20.7% 1,2-propylene glycol, 17.8% ethylene glycol, and 12.7% tetrahydrofuran dimethanol. The Nb2O5/CNT and ZrO2/CNT were inert to C-C bond cracking, whereas H+ in hot compressed water and the Bronsted acid in Nb2O5/CNT accelerated dehydration, yielding more sorbitol and sorbitans. The results provide reference for catalyst selection and product regulation in cellulose hydrogenolysis.
... The acid catalyzed hydrolysis of (hemi)cellulose is one of the key reactions to produce bio-based platform chemicals, fuels and materials. While the depolymerization of cellulose has been extensively explored during the last years [3][4][5][6][7][8][9], studies on hemicellulose are scarce. Unlike cellulose, hemicellulose is an amorphous polysaccharide consisting of different C 5 and C 6 sugars. ...
Acidic Polyoxometalates have been identified as promising catalysts for the hydrolysis of lignocellulosic biomass. They possess a high Brønsted acidity but are soluble in water and most organic solvents, which impedes their recycling and thus industrial application. To develop a solid acid catalyst with both good activity and recyclability, phosphotungstic acid (PTA) was immobilized on activated carbon (AC) by equilibrium impregnation. Characterization of the catalyst materials revealed a stabilizing effect by oxygen functional groups on the support material by increasing the polarity of the support material and enabling a chemical interaction between the heteropolyacid and the surface. PTA/AC was applied in the hydrolysis of the hemicellulose xylan as an aqueous model reaction, selectively yielding the biorefinery platform compound xylose with up to 74% yield. The catalyst can be easily separated from the reaction system and possesses good reusability over 20 recycling runs with a low constant leaching of 3-4% per run.
... Decreasing petroleum reserves leads to the need of renewable feed-stocks for the manufacture of glycols and glycerols. Lignocellulose, obtained from bio waste, is non-edible [12,13] and one of the important renewable resources which can be directly converted to glycols [14][15][16][17][18][19][20]. The direct conversion of cellulosic biomass into valuable chemicals like glycols through hydrogenation is the topic of interest for many decades in the literature [11][12][13][14][15][16][17][18][19][20]. ...
... Lignocellulose, obtained from bio waste, is non-edible [12,13] and one of the important renewable resources which can be directly converted to glycols [14][15][16][17][18][19][20]. The direct conversion of cellulosic biomass into valuable chemicals like glycols through hydrogenation is the topic of interest for many decades in the literature [11][12][13][14][15][16][17][18][19][20]. Yuan et al. [11] reviewed about the various reactions like hydrolyzation, dehydration, hydrogenation or hydrogenolysis and selective oxidation of lignocellulosic carbohydrates into various value-added chemicals. ...
In this article, the results of sorbitol hydrogenolysis (15% aq. solution), done in an autoclave reactor, over Ru, Pt and Ni loaded on SBA15, carbon coated SBA15 (SBA15C), activated carbon (AcC), Na–Y, Fly Ash (FA) and hydroxyapatite (HAP) catalysts by our group, were compared to find the best metal-support combinations. The metal loading was 1 wt% for Ru and Pt, 6 wt% for Ni and the catalysts' preparations were carried out by impregnation of respective salts. The catalysts were characterized with nitrogen and hydrogen adsorption measurements and X-ray diffraction. Addition of a base (Calcium hydroxide) to the reactants' mixture increased the overall conversion and selectivities of the glycols, ethylene glycol (EG) and 1,2-propylene glycol (PG). The catalysts’ performance at 60 bar and 220 °C with the presence of base (B), evaluated by the yield of glycols (PG + EG), showed the following order:
Ni/Na–Y > Ru/AcC ∼ Ru/SBA15C > Ni/HAP ∼ Ru/SBA15 > Ni/SBA15 > Ru/Na–Y > Ni/FA ∼ Ni/AcC and the yields were 57, 40, 39, 33, 31, 29, 26, 22 and 21 wt%, respectively.
Na–Y appeared to be the best support, especially for Ni metal; AcC and SBA15C were good supports for Ru and Pt respectively. Reusability studies revealed that Ni on HAP was the best catalyst and exhibited only a small deactivation during four runs of loading it.
... Besides the excellent hydrogenation activity, the catalyst should have a higher activation barrier for the dehydrogenation and hydrogenolysis of hexitols than desorption energy of hexitols to favor hexitol desorption rather than their further undesired transformation [50] (Figure 12). Many works are devoted to different combination of Ru-based catalysts and mineral acids or Ru catalysts supported on the carrier with acid sites [51,52], while data on hydrolytic hydrogenation over the catalysts with non-noble metal are rarely reported. In the literature on cellulose conversion to hexitols conducted on catalysts with base metals, Ni-containing catalysts were mostly studied [53] (Table 2). ...
... In the literature on cellulose conversion to hexitols conducted on catalysts with base metals, Ni-containing catalysts were mostly studied [53] (Table 2). It should be noted that the main challenge in hydrolytic hydrogenation of cellulose is the selectivity because the acid sites on catalyst or acids used as co-catalyst induce the retro-aldol reaction of intermediate glucose and fructose giving rise to glycol aldehyde or 1,3-dihydroxyacetone [52]. Moreover, the formation of hexitols from cellulose require the use of much higher temperatures (>200 • C) than hydrogenation of monosaccharides because of the need to induce the rate-limiting cellulose hydrolysis step [53]. ...
A new reality of the 21st century is the transition to a new type of economy and energy concepts characterized by the replacement of existing petrochemical routes to a bio-based circular economy. The needs for new strategies in obtaining basic products from bio-based resources with minimum CO2 traces has become mandatory. In this review, recent trends in the conversion of biomass-derived molecules, such as simple monomeric sugars and cellulose, to industrially important C5 and C6 sugar alcohols on heterogeneous catalysts based on non-noble metals are discussed focusing on the influence of catalyst structures and reaction conditions used on the substrate conversion and product selectivity. The challenges and prominent ideas are suggested for the further development of catalytic hydrogenation of naturally abundant carbohydrates to value-added chemicals on non-noble metal catalysts.
... It was demonstrated that W 5+ -OH species on the surface of WO3 (solid acid) act as active catalytic sites where the cleavage of the C2-C3 bond in glucose, forming glycolaldehyde which is then hydrogenated to EG on the Ru/C surface. [11], [12]. ...
ABSTRACT: The numerous uses of Ethylene Glycol both domestically and industrially has made it become an attractive prospect in the chemical industry; especially in cold climates as antifreeze and in plastic production as well as cosmetics. Thus, there is an economic interest to maximize its productivity and minimize the undesirable excesses that comes with its production. Fossil fuel-based ethylene is the main feedstock of the industrial Ethylene Glycol process which we replaced with Biomass in this project and made it a more environment-friendly production route for this much desired chemical. Sugar Bagasse was used to synthesize Ethylene Glycol after exposing its cellulose structure and further catalyzed in a one-pot reaction by a bimetallic mix of 1% Ru-W over activated carbon support, the by-product; propylene glycol was minimized and the utility, mass and energy requirement was determined in the HYSYS simulation environment. Economic analysis revealed that usually the payback period for this project is 2 years on the average ceteris paribus, also the feed basis of 100 kmol/h is relatively more attractive given its marginal cost compared to the opportunity cost of capital, the study also shows that feed rate of over 1000kmol/h is not economically rewarding relative to the marginal change in capital cost and net present value.
... Among the metals active for the target reaction, Ru and Ni have proven to be very interesting [10,19,20]. In fact, this combination, catalysts based on carbon supported Ru and Ni metallic particles has been studied before, showing outstanding results. ...
Catalysts consisting of Ru nanoparticles (1 wt%), supported on mesoporous activated carbons (ACs), were prepared and used in the one-pot hydrolytic hydrogenation of cellulose to obtain sorbitol. The carbon materials used as supports are a pristine commercial mesoporous AC (named SA), and two samples derived from it by sulfonation or oxidation treatments (named SASu and SAS, respectively). The catalysts have been thoroughly characterized regarding both surface chemistry and porosity, as well as Ru electronic state and particle size. The amount and type of surface functional groups in the carbon materials becomes modified as a result of the Ru incorporation process, while a high mesopore volume is preserved upon functionalization and Ru incorporation. The prepared catalysts have shown to be very active, with cellulose conversion close to 50% and selectivity to sorbitol above 75%. The support functionalization does not lead to an improvement of the catalysts’ behavior and, in fact, the Ru/SA catalyst is the most effective one, with about 50% yield to sorbitol, and a very low generation of by-products.
With wooden balls, a visualization of the hydrothermal carbonization to show the progress of the conversion to char is presented. In the present study, the balls represent the particles of biomass to investigate the differences in conversion outside and inside of biomass particles, during hydrothermal carbonization. A special focus is on hydrochar and pyrochar formation. The wooden balls are treated in subcritical water at 220 °C for holding times between 0 and 960 min. Even after 960 min, hydrolysis of the original biomass is incomplete as cellulose and hemicellulose are linked by lignin, inhibiting the reaction with water. Moreover, two different pathways of char production can be observed. Inside of the wooden ball pyrochar is formed as any water got that deep in, on the surface hydrochar is fixed, originated from the surrounding liquid. On the ground of the HTC reactor, a thin, brittle precipitate of likely hydrochar or humins can be found either from the precipitation of loosely attached compounds on the surface of the biomass or direct precipitation from the liquid.
