@article { ISI:000261950600017, title = {Furfural: hemicellulose/xylosederived biochemical}, journal = {Biofuels Bioproducts \& Biorefining-Biofpr}, volume = {2}, number = {5}, year = {2008}, month = {SEP}, pages = {438-454}, publisher = {JOHN WILEY \& SONS LTD}, type = {Review}, address = {THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND}, abstract = {

Hemicellulose, the second, most common polysaccharide in nature constitutes approximately 20-35\% of lignocellulosic biomass. Effective utilization of biomass, hitherto underutilized, is gaining tremendous importance for the production of energy, fuels, and chemicals. Amongst the vast array of chemicals derived from lignocellulosics, furfural is the key chemical that finds wide applications in oil refining, plastics, pharmaceutical and agrochemical industries. There is no synthetic route for the production of furfural. A few conventional technologies currently in practice for its separation and subsequent isolation are appropriately reviewed. Major disadvantages associated with processes currently used for the production of furfural based on acid-catalyzed hydrolysis have been discussed. A need to develop a process which is devoid of all the shortcomings associated with conventional process is emphasized. Several important aspects of chemistry underlying the acid hydrolysis of xylose are discussed. The importance of myriad pre-treatment steps involved to surmount the physical and chemical barriers and to liberate xylose from the confines of acid-resistant layer of lignin has been emphasized. New developments in the production of furfural from cyclodehydration of xylose using solid acid catalysts in the recent past have been reviewed appropriately in present communication. Finally, the production of furfural and furfuryl alcohol, their domestic market and export in China deserve some coverage and therefore have appropriately been discussed as well. (c) 2008 Society of Chemical Industry and John Wiley \& Sons, Ltd

}, keywords = {acid hydrolysis, cyclodehydration, furfural, Hemicellulose, pre-treatment of lignocellulosics, Xylose}, issn = {1932-104X}, doi = {10.1002/bbb.95}, author = {Mamman, Ajit Singh and Lee, Jong-Min and Kim, Yeong-Cheol and Hwang, In Taek and Park, No-Joong and Hwang, Young Kyu and Chang, Jong-San and Hwang, Jin-Soo} } @article { ISI:000326320000017, title = {Efficient, stable, and reusable silicoaluminophosphate for the one-pot production of furfural from hemicellulose}, journal = {ACS Catalysis}, volume = {3}, number = {10}, year = {2013}, month = {OCT}, pages = {2299-2303}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Development of stable, reusable, and water tolerant solid acid catalysts in the conversion of polysaccharides to give value-added chemicals is vital because catalysts are prone to undergo morphological changes during the reactions With the anticipation that silicoaluminophosphate (SAPO) catalysts will have higher hydrothermal stability, those were synthesized, characterized, and employed in a one-pot conversion of hemicellulose. SAPO-44 catalyst at 170 degrees C within 8 h could give 63\% furfural yield with 88\% mass balance and showed similar activity up to at least 8 catalytic cycles. The morphological studies revealed that SAPO catalysts having hydrophilic characteristics are stable under reaction conditions.

}, keywords = {furfural, Hemicellulose, hydrophilicity, SAPO, water-tolerant catalyst, zeolite}, issn = {2155-5435}, doi = {10.1021/cs400495j}, author = {Bhaumik, Prasenjit and Dhepe, Paresh Laxmikant} } @article { ISI:000356739400008, title = {Catalytic conversion of furfural to industrial chemicals over supported Pt and Pd catalysts}, journal = {Journal of Catalysis}, volume = {327}, year = {2015}, month = {JUL}, pages = {65-77}, publisher = {ACADEMIC PRESS INC ELSEVIER SCIENCE}, address = {525 B ST, STE 1900, SAN DIEGO, CA 92101-4495 USA}, abstract = {

Several industrial chemicals were prepared by hydrogenation of furfural over gamma-Al2O3-supported Pt and Pd catalysts. These catalysts were active even at room temperature (25 degrees C). While the Pt catalysts were selective for C=O hydrogenation (yielding furfuryl alcohol), Pd facilitated ring hydrogenation (producing tetrahydrofurfuryl alcohol). At high temperature (240 degrees C), the Pd catalyst exhibited excellent decarbonylation activity forming furan with 85\% yield. The catalyst was reusable even in the absence of external hydrogen. The presence of hydrogen led to ring-opened products. Furan was quantitatively converted at 25 degrees C to tetrahydrofuran. Acidity of the support made a marked influence on the activity and selectivity. Pt on SO4-ZrO2 favored hydrogenolysis yielding 2-methyl furan along with furan with \>75 wt\% selectivity. Particle size, metal dispersion, and solvent influenced catalytic activity. Differences in structure and mode of furfural adsorption were also the causes for variations in selectivity of these supported Pt and Pd catalysts. (C) 2015 Elsevier Inc. All rights reserved.

}, keywords = {Biomass to fuels and chemicals, Decarbonylation, furfural, Hydrogenation, Hydrogenolysis, Supported Pt and Pd catalysts}, issn = {0021-9517}, doi = {10.1016/j.jcat.2015.04.018}, author = {Bhogeswararao, Seemala and Srinivas, D.} } @article { ISI:000354137000012, title = {Effects of careful designing of SAPO-44 catalysts on the efficient synthesis of furfural}, journal = {Catalysis Today}, volume = {251}, year = {2015}, note = {7th Tokyo Conference on Advanced Catalytic Science and Technology (TOCAT), Kyoto, JAPAN, JUN 01-06, 2014}, month = {AUG}, pages = {66-72}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Considering the growing importance of furfural, it is necessary to develop a robust solid acid catalyst for the conversion of xylan (hemicelluloses) into furfural in a one-pot method. In this study, the effects of various components (Si, Al and P) and crystallization time on the preparation of acidic materials and their properties are extensively described. It is seen that with the increase in crystallization time (0, 48, 96, 176 h) during the synthesis of silicoaluminophosphate (SAPO-44), materials morphology changes from amorphous to AFI to CHA and the best activity for furfural synthesis (82\%) from xylan was observed with SAPO-44 catalyst aged for 176 h. Since, acidity in the SAPO-44 is guided by the incorporation of Si in the ALPO framework, study on Si molar concentration (0.8, 1.0, 1.2, 1.4 and 1.6) in SAPO-44 was carried out and it was observed that SAPO-44 having 1.0 mole of Si content is the best catalyst for the xylan/xylose conversion to furfural. Catalyst structure-activity correlation is thoroughly defined with the help of several physico-chemical properties. (C) 2014 Elsevier B.V. All rights reserved.

}, keywords = {Biomass, furfural, Hemicellulose, SAPO-44, Xylose}, issn = {0920-5861}, doi = {10.1016/j.cattod.2014.10.042}, author = {Bhaumik, Prasenjit and Dhepe, Paresh Laxmikant} } @article { ISI:000381122100030, title = {Single pot transfer hydrogenation and aldolization of furfural over metal oxide catalysts}, journal = {Catalysis Letters}, volume = {146}, number = {8}, year = {2016}, month = {AUG}, pages = {1611-1619}, publisher = {SPRINGER}, address = {233 SPRING ST, NEW YORK, NY 10013 USA}, abstract = {

One pot catalytic transfer hydrogenation (CTH) of furfural to furfuryl alcohol (FAL) by using hydrogen producing alcohols and simultaneous aldolization of carbonyl compounds produced during CTH, with furfural was achieved over non-noble metal oxides with bifunctional sites. Basic sites of MgO responsible for abstraction of proton showed complete conversion of furfural to give FAL and C8 monomer in a ratio of 3:1, respectively, the later altered to 1:1 by incorporating Al into MgO. Catalyst stability was established by its four cycles study. [GRAPHICS]

}, keywords = {Aldol, furfural, Furfuryl alcohol, Metal oxides, transfer hydrogenation}, issn = {1011-372X}, doi = {10.1007/s10562-016-1786-6}, author = {Biradar, Narayan S. and Hengne, Amol M. and Sakate, S. S. and Swami, R. K. and Rode, Chandrashekhar V.} } @article { ISI:000370664300002, title = {Solid acid catalyzed synthesis of furans from carbohydrates}, journal = {Catalysis Reviews-Science and Engineering}, volume = {58}, number = {1}, year = {2016}, month = {JAN}, pages = {36-112}, publisher = {TAYLOR \& FRANCIS INC}, type = {Article}, address = {530 WALNUT STREET, STE 850, PHILADELPHIA, PA 19106 USA}, abstract = {

The alternative feedstock, biomass (particularly lignocelluloses), having the profuse availability, is promising for the synthesis of several value-added chemicals which are currently obtained from fossil feedstock. In this article, the synthesis of two extremely significant furan chemicals viz. furfural and 5-hydroxymethylfurfural (HMF) are discussed. In the synthesis of furans from biomass, numerous challenges, i.e., use of edible sugars as substrates, selectivity to furans, their isolation in pure form, reuse of catalyst, environmental issues, etc., are perceived and in the recent past researchers tried to resolve those by developing advance methodologies. This article comprehensively summarizes the latest progress made in the above-mentioned areas and also provides commentary on the analyses of results, rationale for observed activity and mechanisms, etc. It also discusses future aspects of this work.

}, keywords = {Biomass conversion, carbohydrates, cellulose, furans, furfural, hemicelluloses, HMF, solid acid catalyst}, issn = {0161-4940}, doi = {10.1080/01614940.2015.1099894}, author = {Bhaumik, Prasenjit and Dhepe, Paresh Laxmikant} } @article {44025, title = {One pot conversion of furfural to 2-methylfuran in the presence of PtCo bimetallic catalyst}, journal = {Clean Technologies and Environmental Policy}, volume = {20}, year = {2018}, month = {MAY}, pages = {703-713}, type = {Article in Press}, abstract = {

Biomass-derived furfural (FAL) is the platform chemical for synthesis of various value-added chemicals and fuels. One of the FAL-derived chemicals, i.e., 2-methylfuran (2-MF), is the potential biofuel due to its attractive chemical and physical properties. Various methods are reported for conversion of FAL to 2-MF which are operated at high temperature and high H2 pressure. In present work, one pot catalytic method was developed in batch mode process for conversion of FAL to 2-MF. Reactions are carried out in the presence of PtCo/C bimetallic catalyst under 0.5{\textendash}1 MPa H2 pressure. Monometallic and bimetallic catalysts with different Pt and Co loading were prepared by wet impregnation method, and catalysts were characterized by transmission electron microscopy, BET surface area, X-ray photoelectron spectroscopy, X-ray diffraction and inductive coupled plasma atomic emission spectroscopy techniques. 59\% 2-MF yield was achieved at 180 {\textdegree}C and lower (0.5 MPa) H2 pressure.

}, keywords = {2-Methylfuran, Bimetallic catalyst, Co-impregnation, furfural, Hydrodeoxygenation, Hydrogenation}, doi = {10.1007/s10098-017-1408-z}, author = {Dohade, M.G. and Dhepe, P. L.} } @article {44592, title = {Ti-doped Pd-Au catalysts for one-pot hydrogenation and ring opening of furfural}, journal = {Catalysts}, volume = {8}, year = {2018}, month = {JUN}, pages = {252}, abstract = {

Pd-Au bimetallic catalysts with different Pd/Au atomic ratios, supported on ordered structured silica (Hexagonal mesoporous silica-HMS, or Santa Barbara Amorphous-15-SBA-15) were evaluated for one-pot hydrogenation of furfural to 1,2-pentanediol. The surface and structural properties of the catalysts were deeply investigated by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), N-2 adsorption isotherms (BET), Infrared spectroscopy (IR), and acid capacity measurements. XPS studies revealed that Ti doped supports had higher dispersion of the active phase, particularly in the case of Pd-Au materials in which Ti played an important role in stabilizing the metallic species. Among the various process conditions studied, such as temperature (160 degrees C), catalyst amount (10\% w/w), and reaction time (5 h), H-2 pressure (500 psi) was found to improve the 1,2-pentanediol selectivity. The SBA silica bimetallic Ti-doped system showed the best performance in terms of stability and reusability, after multiple cycles. Under specific reaction conditions, the synergism between Pd-Au alloy and Ti doping of the support allowed the ring opening pathway towards the formation of 1,2-pentanediol in furfural hydrogenation.

}, keywords = {Bimetallic catalyst, furfural, Hydrogenation, ring-opening}, issn = {2073-4344}, doi = {10.3390/catal8060252}, author = {Date, Nandan Shreehari and La Parola, Valeria and Rode, Chandrashekhar Vasant and Testa, Maria Luisa} } @article {46020, title = {Pyridine immobilised on magnetic silica as an efficient solid base catalyst for Knoevenagel condensation of furfural with acetyl acetone}, journal = {Catalysis Communications}, volume = {124}, year = {2019}, month = {MAY }, pages = {81-85}, type = {Article}, abstract = {

Novel heterogeneous pyridine immobilised magnetic silica (Fe3O4@SiO2-Py) was found to be an efficient, greener and heterogeneous solid base catalyst for the Knoevenagel condensation of furfural with acetylacetone under optimized reaction conditions. The Knoevenagel condensation product 3-(2-furylmethylene)-2,4-pentanedione (FMP), a jet fuel precursor, was produced in high yield of 85\% with 94\% conversion of furfural at 100 degrees C within a period of 4 h. Fe3O4@SiO2-Py catalyst showed excellent stability and recyclability without losing its initial activity.

}, keywords = {furfural, Jet fuel, Knoevenagel condensation, Silica immobilised pyridine, Solid base}, issn = {1566-7367}, doi = {10.1016/j.catcom.2019.03.005}, author = {Tarade, Komal and Shinde, Suhas and Sakate, Sachin and Rode, Chandrashekhar} } @article {46755, title = {Maximization of furanic compounds formation by dehydration and hydrogenation of xylose in one step over SO3-H functionalized H-beta catalyst in alcohol media}, journal = {Biomass \& Bioenergy}, volume = {139}, year = {2020}, month = {AUG}, pages = {105646}, type = {Article}, abstract = {

Furanic compounds such as furfural (FUR); furfuryl alcohol (F. Alc) are important renewable platform chemicals can be used as such or further convert for preparation of other value added products such as Levulinic acid (LA), Alkyl Levulinates, 2-Methyltetrahydrofuran (MTHF), and Tetrahydrofuran (THF) etc. Sulfonated H-beta zeolite was successfully prepared and used for the synthesis of furanic compounds especially FUR and F. Alc from c-xylose in one step using isopropanol as alcohol media. Prepared catalyst was well characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM), BET, NH3-Temperature programmed desorption (TPD) and carbon-hydrogen-nitrogen-sulfur analysis (CHNS). It was found the total acid amount was increased with increase in sulfur loading which confirmed the sulfonic acid group (SO3-H) was successfully grafted onto zeolite structure. 3 wt\% H-beta-SO3-H catalyst with optimized reaction parameters of 150 degrees C, 7 h, 25 wt\% catalyst loading was tuned to get the highest furanic compound yield of 88.5\% (FUR 76.8\% + F.Alc 11.7\%).The reusability study confirmed that there was a marginal drop of similar to 25\% after 3 recycle runs.

}, keywords = {furfural, Furfuryl alcohol, H-beta, isopropanol, sulfonated zeolite, Xylose}, issn = {0961-9534}, doi = {10.1016/j.biombioe.2020.105646}, author = {Gupta, Anshita and Nandanwar, Sachin U. and Niphadkar, Prashant and Simakova, Irina and Bokade, Vijay} } @article {46738, title = {One pot hydrogenation of furfural to 2-methyl tetrahydrofuran over supported mono- and Bi-metallic catalysts}, journal = {ChemistrySelect}, volume = {5}, year = {2020}, month = {AUG }, pages = {9590-9600}, type = {Article}, abstract = {

2-Methyltetrahydrofuran is a valuable commercial product that can be obtained by direct hydrogenation of furfural. In the present study, among several carbon supported bimetallic Ir-Ni catalysts with different loadings screened, 4\% Ir-4\% Ni/C catalyst showed excellent activity in terms of direct conversion (99\%) to 2-MeTHF with a maximum selectivity of similar to 74\% at 220 degrees C and 750 psig, suppressing the formation of side chain as well as ring opening products. The catalytic activity was found to be mainly affected by catalyst preparation methods, metal loadings, surface composition, temperature, pressure and catalyst loading. HR-TEM and STEM revealed well dispersed Ir-Ni NPs having the particle sizes in the range of 2 to 5 nm. Different phases of Ir i. e. Ir degrees and IrO(2)as well as oxygen vacancies were found to be responsible for hydrogenation of furfural to 2-methyl furan while, Ni degrees and NiO were responsible for further hydrogenation to 2-MeTHF. The synergic effect between Ir and Ni was established through XPS, H-2-TPR analysis. With the help of some control experiments, the plausible reaction pathway was also proposed. The catalyst prepared by co-impregnation method found more effective than prepared by sequential addition method. At lower Ni loadings of 1\% and 2\%, low temperature of 160 degrees C as well as at low H(2)pressure of 250 psig, mixture of furfuryl alcohol and 2-methyl furan were formed selectively. Catalyst could be successfully reused up to 3 times without leaching of metals.

}, keywords = {2-Methyltetrahydrofuran, Bimetallic catalyst, furfural, Hydrogenation, OER type mechanism}, issn = {2365-6549}, doi = {10.1002/slct.202002322}, author = {Date, Nandan S. and Hengne, Amol M. and Huang, K. -W. and Chikate, Rajeev C. and Rode, Chandrashekhar V.} } @article {49636, title = {Effect of furfural, acetic acid and 5-hydroxymethylfurfural on yeast growth and xylitol fermentation using Pichia stipitis NCIM 3497}, journal = {Biomass Conversion and Biorefinery}, volume = {14}, year = {2024}, month = {FEB}, pages = {4909-4923}, type = {Article}, abstract = {

The valorization of C5 sugars (xylose) from hemicellulose of agro-industrial residues to xylitol, as one of the multi-products biorefinery approach, mandates the pretreatment of biomass which releases fermentable sugars along with the generation of biological inhibitors affecting xylitol fermentation. This study was therefore evaluated to understand the inhibitory kinetics of furfural, 5-hydroxymethylfurfural and acetic acid on xylitol fermentation. Xylitol fermentation was established using Pichia stipitis NCIM 3497 with xylose as a pure substrate optimized for xylitol yield and productivity of 0.48 g/g of xylose and 0.13 g/L/h, respectively. The functional relationship of yeast specific growth rate and limiting substrate (xylose) was expressed by Monod-type kinetics. The inhibition kinetics results indicated that the effect of inhibitors on xylitol fermentation was furfural \> acetic acid \> HMF. Furfural (500 mg/L) and acetic acid (1000 mg/L) reduced xylitol yield by 59\% and 44\%, respectively, with least reduction of 9.89\% exhibited by HMF. The synergistic effect of 500 mg/L furfural, 500 mg/L HMF and 1000 mg/L acetic acid showed the highest reduction in xylitol yield of 67.6\% as compared to the control. Kinetic studies predicted that the maximum concentration of furfural, HMF and acetic acid which inhibited P. stipitis growth was 884 mg/L, 3258 mg/L and 2922 mg/L, respectively, whereas xylitol production was completely inhibited at 1069 mg/L furfural, 3498 mg/L HMF and 3714 mg/L acetic acid. Furfural and acetic acid were found to be a competitive inhibitor, while uncompetitive inhibition was observed with HMF indicating negligible effect on xylitol fermentation.

}, keywords = {Acetic acid, furfural, HMF, Inhibition kinetics, Pichia stipitis, Xylitol fermentation}, issn = {2190-6815}, doi = {10.1007/s13399-022-02758-w}, author = {Bhavana, B. K. and Mudliar, Sandeep N. and Bokade, V. V. and Debnath, S.} } @article {49084, title = {Hydrogenation of furfural to tetrahydrofurfuryl alcohol over nickel-supported on organoclay catalyst}, journal = {Applied Catalysis A-General}, volume = {674}, year = {2024}, month = {MAR }, pages = {119621}, type = {Article}, abstract = {

Nickel supported on organoclay prepared by the impregnation method provides excellent catalytic activity for the hydrogenation of furfural to tetrahydrofurfuryl alcohol. The relative amount of metal and acidic sites influences the hydrogenation reaction. Additionally, by varying the temperature and the H-2 pressure, we can regulate the interaction of furfural with the active sites. And this may decide the fate of the reaction whether it will undergo a two-step hydrogenation to form tetrahydrofurfuryl alcohol or a rearrangement reaction to form cyclopentanone/cyclopentanol. Water was found to be the best solvent for the selective formation of tetrahydrofurfuryl alcohol. Even though alcohols inhibited rearrangement reaction, the hydrogenation of furfural was more selective towards furfuryl alcohol. Ni/O-clay30A under the optimum conditions of 120 degrees C, 4.0 MPa, and in 1 h offered complete conversion of furfural to tetrahydrofurfuryl alcohol.

}, keywords = {furfural, Hydrogenation, Nickel, organoclay, Tetrahydrofurfuryl alcohol}, issn = {0926-860X}, doi = {10.1016/j.apcata.2024.119621}, author = {Kamble, Paresh A. and Vinod, C. P. and Rathod, Virendra K. and Kantam, Mannepalli Lakshmi} } @article {49520, title = {Enhanced Production and Techno-Economic Analysis of Sustainable Biofuel Production via Continuous Hydrogenation of Furfural Using the Cu-ZnO-Al2O3 Catalyst}, journal = {ACS Sustainable Chemistry \& Engineering}, volume = {13}, year = {2025}, month = {FEB}, pages = {3183-3199}, type = {Review}, abstract = {

2-Methylfuran is a perfect green solution on the pathway of finding alternative fuels. We report here for the first time the continuous production of 2-methylfuran (2-MF), a sustainable biofuel from biomass-derived furfural (FFA), over an industrial Cu-ZnO-Al2O3 (CZA) catalyst. The modified coprecipitation method provides a uniformly dispersed crystalline structure to the synthesized catalysts, along with intended copper (Cu) loading achievement. Different Cu loadings affect the catalytic behavior and activity. Hence, CZA catalysts with two Cu loadings of 9.8 and 4.7\% were studied in detail, denoted as C1 and C2, respectively. The catalysts were characterized via XRD, N-2 adsorption, H-2-TPR, NH3-TPD, XPS, ICP-MS, and TEM. Remarkably, the prepared catalysts demonstrate balanced acid sites with mesopores, a high surface area and pore volume, and better controlled nanoparticle size promoting catalytic activity. TEM and H-2-TPR studies reveal a better Cu dispersion. Existence of Cu2+ and Cu (+) even after reduction by XPS study proves the efficiency of the synthesized catalysts. Furthermore, TGA indicates the stability of CZA catalysts. To understand catalytic activity and selectivity, the investigation was carried out in a packed-bed fixed-bed stainless steel reactor. Better physiochemical properties result in high FFA conversion of 33.8\% and selectivity of 99.6\% for 2-MF. No side products were formed during reaction otherwise improbable via the continuous method. Compared with available literature, the CZA catalyst was found to exhibit superior catalytic performance. The reaction kinetics of furfural hydrogenation to 2-methylfuran was investigated, and it was found that the reaction order is high, and the activation energy was 61.2 kJ/mol. The rate constant k clearly obeyed the Arrhenius law from 180 to 220 degrees C. In addition, evaluation of reaction kinetics also indicated the absence of ring hydrogenation and decarbonylation products, which is difficult to achieve. Finally, the process shows significant economic viability, which resulted in the minimum levelized production cost for 2-methylfuran of 173,068.16 \$/ton with 78.32\% overall energy efficiency.

}, keywords = {2-methylfuran (2-MF), continuous production, Cu-ZnO-Al2O3, economic viability, furfural, green synthesis}, issn = {2168-0485}, doi = {10.1021/acssuschemeng.4c08820}, author = {Saha, Biswajit and Racha, Arundhathi and Chaudhary, Puneet Kumar and Singh, Brijesh Kumar and Samanta, Chanchal and Newalkar, Bharat L.} } @article {49729, title = {Facet dependence for solvent-modulated proton-coupled electron transfer in furfural acetalization on Pd nanostructures}, journal = {Chemical Engineering Journal}, volume = {514}, year = {2025}, month = {JUN}, pages = {163159}, type = {Article}, abstract = {

Furfural dialkyl acetals prepared via acetalization reaction of furfural and alcohols are promising biofuels. Using defined experiments and density functional theory (DFT) simulations, the structure-dependent activity and selectivity for furfural acetalization reaction in the presence of alcohols (methanol, ethanol, propanol and butanol) as solvents was studied over well-defined supported Pd nanostructures (octahedra (111), cubes (100) and spheres (both (111) and (100)). Pd cubes supported over TiO2 in the presence of ethanol as a solvent (at 303 K and balloon pressure H-2) exhibited 78 \% conversion and 100 \% selectivity for furfural diethyl acetal product in a short time (similar to 180 min). In contrast, Pd octahedra (111) and Pd spheres showed low conversions (18 \% and 6 \%) at the same reaction conditions. Interestingly, when used as a solvent, methanol showed the highest conversion (90 \%) and selectivity (100 \%) for furfural acetalization over Pd cubes. DFT simulations provided mechanistic insight into the reactivity of the two different Pd facets (111) and (100) in the presence of alcohol molecules towards furfural acetalization reaction. A three-step reaction mechanism was proposed for furfural acetalization with alcohols: (i) alcohol hydroxyl-dehydrogenation (ii) hydrogenation of furfural carbonyl oxygen, and (iii) formation of hemiacetal product. For all three steps, Pd (100) exhibited low activation barriers (51.6, 26.7 and 76.2 kJ/mol) compared to Pd (111) surface (78.6, 35.8 and 92.2 kJ/mol) in the presence of ethanol. The activation barriers for the above steps were further reduced to 47.8, 23.9 and 64.6 kJ/mol on Pd (100) in the presence of methanol, explaining the experimental high reactivity aided by methanol. DFT calculations elucidated the role of the hydrogen bonding network between the solvent molecules and adsorbate, enabling proton-coupled electron transfer for accelerated reactions.

}, keywords = {Acetalization, DFT, facet-dependent reactivity, furfural, Furfural dialkyl acetals, solvent effect}, issn = {1385-8947}, doi = {10.1016/j.cej.2025.163159}, author = {Porwal, Govind and Dandekar, Pallavi and Gorai, Twinkle and Khan, Tuhin Suvra and Haider, M. Ali and Gupta, Shelaka and Vinod, C. P.} }