Catalytic conversion of cellulosic biomass to ethylene glycol: Effects of inorganic impurities in biomass

KIO4 -mediated Selective Hydroxymethylation/Methylenation of Imidazo-Heteroarenes: A Greener Approach

Herein, we report a KIO₄ -mediated, sustainable and chemoselective approach for the one-pot C(sp² )-H bond hydroxymethylation or methylenation of imidazo-heteroarenes with formaldehyde, generated in situ via the oxidative cleavage of ethylene glycol or glycerol (renewable reagents) through the Malaprade reaction. In the presence of ethylene glycol, a series of 3-hydroxymethyl-imidazo-heteroarenes was obtained in good to excellent yields. These compounds are important intermediates to access pharmaceutical drugs, e.g., Zolpidem. Furthermore, by using glycerol, bis(imidazo[1,2-a]pyridin-3-yl)methane derivatives were selectively obtained in good to excellent yields.

Simultaneous production of 1,6-hexanediol, furfural, and high-purity lignin from white birch: Process integration and techno-economic evaluation

An integrated strategy of multiple catalytic conversions was developed to completely utilize three major fractions of biomass, thereby increasing the revenue from lignocellulosic biomass (white birch). Cellulose was converted into 1,6-hexanediol (1,6-HDO) with a yield of 21.8% via a series of catalytic conversions, hemicellulose was converted into furfural with a yield of 87.2% via dehydration, and lignin was purified into high-purity lignin with a yield of 71.7% via two-step purification. Heat integration was performed to mitigate the challenges associated with the large energy requirements of the process. Additionally, a techno-economic analysis was conducted to investigate the feasibility of the proposed process. The minimum selling price (MSP) of 1,6-HDO is estimated to be $3,922/ton, meaning that the economics of the proposed process are favorable compared to petroleum-derived 1,6-HDO production ($4,400/ton). The effect of economic parameters on the MSP of 1,6-HDO was also investigated via a wide array of sensitivity analyses.

Optimization Study of Biomass Hydrogenation to Ethylene Glycol Using Response Surface Methodology

Statistical-based study using response surface methodology (RSM) was conducted to study the effects of process parameters towards biomass hydrogenation. Using Malaysian oil palm empty fruit bunches (EFB) fibres as feedstock, the central composite design (CCD) technique was employed and 18 runs were generated by CCD when four parameters (mass ratio of binary catalyst, hydrogen pressure, temperature and mass ratio of catalyst to feedstock) were varied with two center points to determine the effects of process parameters and eventually to get optimum ethylene glycol (EG) yield. RSM with quadratic function was generated for biomass hydrogenation, indicating all factors except temperature, were important in determining EG yield. Analysis of variance (ANOVA) showed a high coefficient of determination (R2) value of >0.98, ensuring a satisfactory prediction of the quadratic model with experimental data. The quadratic model suggested the optimum EG yield should be >25 wt.% and the EG yield results were successfully reproduced in the laboratory.

Selective Conversion of Cellulose to Hydroxyacetone and 1-Hydroxy-2-Butanone with Sn-Ni Bimetallic Catalysts

The high-value-added chemicals hydroxyacetone (HA) and 1-hydroxy-2-butanone (HB) were produced from agricultural waste over a Ni₃ Sn₄ -SnO_x catalyst. The Sn-Ni intermetallic compound and SnO_x acted as the active sites for HA and HB production by selectively cleaving the target C-C and C-O bonds. Approximately 70 % of the total HA and HB yield was obtained by selective hydrogenolysis of cellulose. This strategy expands the application of cellulose towards renewable production of high-value C₃ and C₄ keto-alcohols from cellulosic biomass.

Effect of tungsten surface density of WO3–ZrO2 on its catalytic performance in hydrogenolysis of cellulose to ethylene glycol

New understanding on reaction mechanism of cellulose hydrogenolysis to ethylene glycol over WO₃–ZrO₂ catalyst combined with Ru/C.

From Barley Straw to Valuable Polyols: A Sustainable Process Using Ethanol/Water Mixtures and Hydrogenolysis over Ruthenium-Tungsten Catalyst

Organosolv fractionation of barley straw followed by a hydrogenolysis reaction of the resulting organosolv pulp over a heterogeneous catalyst containing ruthenium and tungsten on activated carbon (Ru-W/AC) is a potential pathway to produce valuable chemicals from lignocellulose-based feedstock in a future biorefinery. Polyols, such as ethylene glycol, propylene glycol, or 1,2-butanediol, can be obtained with a very high yield of 70 % using organosolv barley pulp pretreated in a 50:50 wt % ethanol/water solution at 200 °C and a processing time of one hour. Moreover, we investigated the influence of several pretreatment parameters (e.g., solvent/water ratio, reaction temperature, and reaction time) on the pulp composition and product distribution obtained during the hydrogenolysis reaction to reduce the production of undesired side molecules. Finally, the optimal organosolv pretreatment conditions for straw were successfully transferred to other lignocellulose-based feedstock, namely bamboo foliage and hemp shives.

Promotion effects of Pd on tungsten carbide catalysts: physiochemical properties and cellulose conversion performance

A multi-functional catalyst, which is able to perform both retro-aldol reactions followed by hydrogenation, is required to convert cellulose into value-added chemicals such as ethylene glycol (EG) in a one-pot reaction.

Conversion of biomass-derived sorbitol to glycols over carbon-materials supported Ru-based catalysts

Ruthenium (Ru) supported on activated carbon (AC) and carbon nanotubes (CNTs) was carried out in the hydrogenolysis of sorbitol to ethylene glycol (EG) and 1,2-propanediol (1,2-PD) under the promotion of tungsten (WO_x) species and different bases. Their catalytic activities and glycols selectivities strongly depended on the support properties and location of Ru on CNTs, owning to the altered metal-support interactions and electronic state of ruthenium. Ru located outside of the tubes showed excellent catalytic performance than those encapsulated inside the nanotubes. Additionally, the introduction of WO_x into Ru/CNTs significantly improved the hydrogenolysis activities, and a complete conversion of sorbitol with up to 60.2% 1,2-PD and EG yields was obtained on RuWO_x/CNTs catalyst upon addition of Ca(OH)₂. Stability study showed that this catalyst was highly stable against leaching and poisoning and could be recycled several times.