{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,8,18]],"date-time":"2026-08-18T04:58:11Z","timestamp":1787029091545,"version":"build-2736575974"},"reference-count":74,"publisher":"MDPI AG","issue":"24","license":[{"start":{"date-parts":[[2021,12,8]],"date-time":"2021-12-08T00:00:00Z","timestamp":1638921600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100004396","name":"Thailand Research Fund","doi-asserted-by":"publisher","award":["RSA6280074"],"award-info":[{"award-number":["RSA6280074"]}],"id":[{"id":"10.13039\/501100004396","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100004396","name":"Thailand Research Fund","doi-asserted-by":"publisher","award":["RTA6280003"],"award-info":[{"award-number":["RTA6280003"]}],"id":[{"id":"10.13039\/501100004396","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Molecules"],"abstract":"<jats:p>Biomass valorization to building block chemicals in food and pharmaceutical industries has tremendously gained attention. To produce monophenolic compounds from palm empty fruit bunch (EFB), EFB was subjected to alkaline hydrothermal extraction using NaOH or K2CO3 as a promotor. Subsequently, EFB-derived lignin was subjected to an oxidative depolymerization using Cu(II) and Fe(III) mixed metal oxides catalyst supported on \u03b3-Al2O3 or SiO2 as the catalyst in the presence of hydrogen peroxide. The highest percentage of total phenolic compounds of 63.87 wt% was obtained from microwave-induced oxidative degradation of K2CO3 extracted lignin catalyzed by Cu-Fe\/SiO2 catalyst. Main products from the aforementioned condition included 27.29 wt% of 2,4-di-tert-butylphenol, 19.21 wt% of syringol, 9.36 wt% of acetosyringone, 3.69 wt% of acetovanillone, 2.16 wt% of syringaldehyde, and 2.16 wt% of vanillin. Although the total phenolic compound from Cu-Fe\/Al2O3 catalyst was lower (49.52 wt%) compared with that from Cu-Fe\/SiO2 catalyst (63.87 wt%), Cu-Fe\/Al2O3 catalyst provided the greater selectivity of main two value-added products, syringol and acetosyrigone, at 54.64% and 23.65%, respectively (78.29% total selectivity of two products) from the NaOH extracted lignin. The findings suggested a promising method for syringol and acetosyringone production from the oxidative heterogeneous lignin depolymerization under low power intensity microwave heating within a short reaction time of 30 min.<\/jats:p>","DOI":"10.3390\/molecules26247444","type":"journal-article","created":{"date-parts":[[2021,12,8]],"date-time":"2021-12-08T23:30:00Z","timestamp":1639006200000},"page":"7444","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":22,"title":["Lignin-Derived Syringol and Acetosyringone from Palm Bunch Using Heterogeneous Oxidative Depolymerization over Mixed Metal Oxide Catalysts under Microwave Heating"],"prefix":"10.3390","volume":"26","author":[{"given":"Rangsalid","family":"Panyadee","sequence":"first","affiliation":[{"name":"Department of Chemical Engineering, Faculty of Engineering, Mahidol University, 999 Putthamonthon 4 Road, Salaya, Putthamonthon, Nakorn Pathom 73170, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Aphinan","family":"Saengsrichan","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, Faculty of Engineering, Mahidol University, 999 Putthamonthon 4 Road, Salaya, Putthamonthon, Nakorn Pathom 73170, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Pattaraporn","family":"Posoknistakul","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, Faculty of Engineering, Mahidol University, 999 Putthamonthon 4 Road, Salaya, Putthamonthon, Nakorn Pathom 73170, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Navadol","family":"Laosiripojana","sequence":"additional","affiliation":[{"name":"The Joint Graduate School of Energy and Environment (JGSEE), King Mongkut\u2019s University of Technology Thonburi, 126 Pracha Uthit Road, Bang Mot, Tungkru, Bangkok 10140, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sakhon","family":"Ratchahat","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, Faculty of Engineering, Mahidol University, 999 Putthamonthon 4 Road, Salaya, Putthamonthon, Nakorn Pathom 73170, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-9640-1567","authenticated-orcid":false,"given":"Babasaheb M.","family":"Matsagar","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, National Taiwan University, No.1, Sec. 4 Roosevelt Road, Taipei City 10617, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0590-1396","authenticated-orcid":false,"given":"Kevin C.-W.","family":"Wu","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, National Taiwan University, No.1, Sec. 4 Roosevelt Road, Taipei City 10617, Taiwan"},{"name":"Center of Atomic Initiative for New Materials (AI-MAT), National Taiwan University, Taipei City 10617, Taiwan"},{"name":"International Graduate Program of Molecular Science and Technology, National Taiwan University (NTU), Taipei City 10617, Taiwan"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0195-2236","authenticated-orcid":false,"given":"Chularat","family":"Sakdaronnarong","sequence":"additional","affiliation":[{"name":"Department of Chemical Engineering, Faculty of Engineering, Mahidol University, 999 Putthamonthon 4 Road, Salaya, Putthamonthon, Nakorn Pathom 73170, Thailand"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,12,8]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"121878","DOI":"10.1016\/j.biortech.2019.121878","article-title":"Advances in lignin valorization towards bio-based chemicals and fuels: Lignin biorefinery","volume":"291","author":"Cao","year":"2019","journal-title":"Bioresour. Technol."},{"key":"ref_2","first-page":"1","article-title":"Oxidative depolymerization of lignins for producing aromatics: Variation of botanical origin and extraction methods","volume":"2020","author":"Kazachenko","year":"2020","journal-title":"Biomass Convers. Biorefinery"},{"key":"ref_3","doi-asserted-by":"crossref","unstructured":"Margellou, A., and Triantafyllidis, K.S. (2019). Catalytic Transfer Hydrogenolysis Reactions for Lignin Valorization to Fuels and Chemicals. Catalysts, 9.","DOI":"10.3390\/catal9010043"},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"2999","DOI":"10.1021\/acsomega.0c05387","article-title":"Upgrading of Light Bio-oil from Solvothermolysis Liquefaction of an Oil Palm Empty Fruit Bunch in Glycerol by Catalytic Hydrodeoxygenation Using NiMo\/Al2O3 or CoMo\/Al2O3 Catalysts","volume":"6","author":"Muangsuwan","year":"2021","journal-title":"ACS Omega"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"384","DOI":"10.1002\/slct.201601736","article-title":"Hydrogenolysis of Benzyl Protected Phenols and Aniline Promoted by Supported Palladium Nanoparticles","volume":"2","author":"Albano","year":"2017","journal-title":"ChemistrySelect"},{"key":"ref_6","doi-asserted-by":"crossref","unstructured":"Espro, C., Gumina, B., Szumelda, T., Paone, E., and Mauriello, F. (2018). Catalytic Transfer Hydrogenolysis as an Effective Tool for the Reductive Upgrading of Cellulose, Hemicellulose, Lignin, and Their Derived Molecules. Catalysts, 8.","DOI":"10.3390\/catal8080313"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"628","DOI":"10.1002\/pat.1130","article-title":"Flammability properties of intumescent PLA including starch and lignin","volume":"19","author":"Casetta","year":"2008","journal-title":"Polym. Adv. Technol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"891","DOI":"10.1016\/j.renene.2018.07.004","article-title":"Concerning operational aspects in supercritical water gasification of kraft black liquor","volume":"130","author":"Molino","year":"2019","journal-title":"Renew. Energy"},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"33","DOI":"10.1016\/j.pecs.2017.05.004","article-title":"Lignocellulosic biomass pyrolysis mechanism: A state-of-the-art review","volume":"62","author":"Wang","year":"2017","journal-title":"Prog. Energy Combust. Sci."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"761","DOI":"10.1016\/j.rser.2015.06.054","article-title":"An overview on fast pyrolysis of the main constituents in lignocellulosic biomass to valued-added chemicals: Structures, pathways and interactions","volume":"51","author":"Shen","year":"2015","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1016\/j.fuproc.2019.04.007","article-title":"Catalytic oxidation of lignin to valuable biomass-based platform chemicals: A review","volume":"191","author":"Liu","year":"2019","journal-title":"Fuel Process. Technol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"10864","DOI":"10.1021\/acssuschemeng.7b02790","article-title":"Catalytic Depolymerization of Lignin and Woody Biomass in Supercritical Ethanol: Influence of Reaction Temperature and Feedstock","volume":"5","author":"Huang","year":"2017","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"4604","DOI":"10.1002\/cctc.201901010","article-title":"Effect of solvent, the role of formic acid and Rh\/C catalysts for the efficient liquefaction of lignin","volume":"11","author":"Matsagar","year":"2019","journal-title":"ChemCatChem"},{"key":"ref_14","doi-asserted-by":"crossref","unstructured":"Singh, R., Prakash, A., Balagurumurthy, B., and Bhaskar, T. (2015). Hydrothermal Liquefaction of Biomass. Recent Advances in Thermo-Chemical Conversion of Biomass, Elsevier.","DOI":"10.1016\/B978-0-444-63289-0.00010-7"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"180","DOI":"10.1016\/j.enconman.2015.03.075","article-title":"Effect of process parameters on hydrothermal liquefaction of oil palm biomass for bio-oil production and its life cycle assess","volume":"104","author":"Chan","year":"2015","journal-title":"Energy Convers. Manag."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"88","DOI":"10.1016\/j.jaap.2011.04.011","article-title":"Thermal reactions of guaiacol and syringol as lignin model aromatic nuclei","volume":"92","author":"Asmadi","year":"2011","journal-title":"J. Anal. Appl. Pyrolysis"},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1186\/1754-6834-6-14","article-title":"Survey of renewable chemicals produced from lignocellulosic biomass during ionic liquid pretreatment","volume":"6","author":"Varanasi","year":"2013","journal-title":"Biotechnol Biofuels"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"10116","DOI":"10.1021\/acssuschemeng.7b02123","article-title":"Survey of Lignin-Structure Changes and Depolymerization during Ionic Liquid Pretreatment","volume":"5","author":"Dutta","year":"2017","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"834","DOI":"10.1039\/C5GC01950H","article-title":"Lignin oxidation and depolymerisation in ionic liquids","volume":"18","author":"Prado","year":"2016","journal-title":"Green Chem."},{"key":"ref_20","doi-asserted-by":"crossref","unstructured":"Zhang, S. (2020). Depolymerization of Lignin by Catalytic Oxidation in Ionic Liquids. Encyclopedia of Ionic Liquids, Springer.","DOI":"10.1007\/978-981-10-6739-6"},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"13508","DOI":"10.1038\/s41598-017-13946-4","article-title":"Direct Production of Furfural in One-pot Fashion from Raw Biomass Using Br\u00f8nsted Acidic Ionic Liquids","volume":"7","author":"Matsagar","year":"2017","journal-title":"Sci. Rep."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"5086","DOI":"10.1039\/C5CY00858A","article-title":"Conversion of concentrated sugar solutions into 5-hydroxymethyl furfural and furfural using Br\u00f6nsted acidic ionic liquids","volume":"5","author":"Matsagar","year":"2015","journal-title":"Catal. Sci. Technol."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"2747","DOI":"10.3390\/molecules14082747","article-title":"Wet Aerobic Oxidation of Lignin into Aromatic Aldehydes Catalysed by a Perovskite-type Oxide: LaFe1-xCuxO3 (x = 0, 0.1, 0.2)","volume":"14","author":"Zhang","year":"2009","journal-title":"Molecules"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"1843","DOI":"10.1039\/D0CY02158J","article-title":"Oxidative depolymerization of Kraft lignin to high-value aromatics using a homogeneous vanadium\u2013copper catalyst","volume":"11","author":"Walch","year":"2021","journal-title":"Catal. Sci. Technol."},{"key":"ref_25","doi-asserted-by":"crossref","unstructured":"Viseshsin, N., Sukhitkul, P., Panyadee, R., Sakdaronnarong, C., and Posoknistakul, P. (2018, January 22\u201323). Study of vanillin formation under oxygen delignification process. In Proceedings of 2018 IEEE 5th International Conference on Engineering Technologies and Applied Sciences (ICETAS 2018), Bangkok, Thailand.","DOI":"10.1109\/ICETAS.2018.8629121"},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"16896","DOI":"10.1021\/acssuschemeng.8b04246","article-title":"Sequential Fractionation of Palm Empty Fruit Bunch and Microwave-Assisted Depolymerization of Lignin for Producing Monophenolic Compounds","volume":"6","author":"Panyadee","year":"2018","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_27","doi-asserted-by":"crossref","unstructured":"Tarabanko, V.E., and Tarabanko, N. (2017). Catalytic Oxidation of Lignins into the Aromatic Aldehydes: General Process Trends and Development Prospects. Int. J. Mol. Sci., 18.","DOI":"10.3390\/ijms18112421"},{"key":"ref_28","first-page":"838645","article-title":"Recent Development in Chemical Depolymerization of Lignin: A Review","volume":"2013","author":"Wang","year":"2013","journal-title":"Appl. Chem."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"618","DOI":"10.1039\/C8RE00304A","article-title":"Efficient liquid-phase hydrogenolysis of a lignin model compound (benzyl phenyl ether) using a Ni\/carbon catalyst","volume":"4","author":"Matsagar","year":"2019","journal-title":"React. Chem. Eng."},{"key":"ref_30","doi-asserted-by":"crossref","unstructured":"Cabral Almada, C., Kazachenko, A., Fongarland, P., Da Silva Perez, D., Kuznetsov, B.N., and Djakovitch, L. (2021). Supported-Metal Catalysts in Upgrading Lignin to Aromatics by Oxidative Depolymerization. Catalysts, 11.","DOI":"10.3390\/catal11040467"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"78","DOI":"10.1016\/j.biortech.2014.02.092","article-title":"Depolymerization of organosolv lignin using doped porous metal oxides in supercritical methanol","volume":"161","author":"Warner","year":"2014","journal-title":"Bioresour. Technol."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"50","DOI":"10.1016\/j.cattod.2017.05.101","article-title":"Recent advances in oxidative valorization of lignin","volume":"302","author":"Ma","year":"2018","journal-title":"Catal. Today"},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"639","DOI":"10.1007\/s11244-019-01146-5","article-title":"Oxidative Depolymerisation of Lignosulphonate Lignin into Low-Molecular-Weight Products with Cu\u2013Mn\/\u03b4-Al2O3","volume":"62","author":"Abdelaziz","year":"2019","journal-title":"Top. Catal."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"3828","DOI":"10.1039\/C8GC00502H","article-title":"Revisiting alkaline aerobic lignin oxidation","volume":"20","author":"Schutyser","year":"2018","journal-title":"Green Chem."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"2107","DOI":"10.1021\/acsomega.9b02379","article-title":"Preparation of Syringaldehyde from Lignin by Catalytic Oxidation of Perovskite-Type Oxides","volume":"5","author":"Li","year":"2020","journal-title":"ACS Omega"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"718","DOI":"10.1021\/ie00027a034","article-title":"Improved Alkaline Oxidation Process for the Production of Aldehydes (Vanillin and Syringaldehyde) from Steam-Explosion Hardwood Lignin","volume":"33","author":"Wu","year":"1994","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"2220","DOI":"10.1080\/09593330.2019.1697376","article-title":"Heterogeneous photo-Fenton oxidation of lignin of rice husk alkaline hydrolysates using Fe-impregnated silica catalysts","volume":"42","author":"Arefieva","year":"2021","journal-title":"Environ. Technol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"1","DOI":"10.3389\/fenrg.2017.00021","article-title":"Catalytic Oxidation and Depolymerization of Lignin in Aqueous Ionic Liquid","volume":"5","author":"Das","year":"2017","journal-title":"Front. Energy Res."},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"54","DOI":"10.1016\/j.polymdegradstab.2016.11.016","article-title":"Lignin depolymerization to aromatic monomers and oligomers in isopropanol assisted by microwave heating","volume":"135","author":"Liu","year":"2017","journal-title":"Polym. Degrad. Stab."},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"238","DOI":"10.1016\/j.biortech.2018.05.083","article-title":"Microwave-assisted efficient depolymerization of alkaline lignin in methanol\/formic acid media","volume":"264","author":"Shao","year":"2018","journal-title":"Bioresour. Technol."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"113515","DOI":"10.1016\/j.indcrop.2021.113515","article-title":"Effect of metal triflates on the microwave-assisted catalytic hydrogenolysis of birch wood lignin to monophenolic compounds","volume":"167","author":"Liu","year":"2021","journal-title":"Ind. Crop. Prod."},{"key":"ref_42","doi-asserted-by":"crossref","first-page":"123490","DOI":"10.1016\/j.jhazmat.2020.123490","article-title":"Microwave-assisted catalytic depolymerization of lignin from birch sawdust to produce phenolic monomers utilizing a hydrogen-free strategy","volume":"402","author":"Liu","year":"2021","journal-title":"J. Hazard. Mater."},{"key":"ref_43","doi-asserted-by":"crossref","first-page":"21308","DOI":"10.1021\/jp3023056","article-title":"FT-IR Investigation of Methoxy Substituted Benzenes Adsorbed on Solid Acid Catalysts","volume":"116","author":"Lucarelli","year":"2012","journal-title":"J. Phys. Chem. C"},{"key":"ref_44","doi-asserted-by":"crossref","first-page":"116","DOI":"10.1016\/j.lwt.2013.11.042","article-title":"Properties of lignin extracted from sugarcane bagasse and its efficacy in maintaining postharvest quality of limes during storage","volume":"57","author":"Jonglertjunya","year":"2014","journal-title":"LWT-Food Sci. Technol."},{"key":"ref_45","doi-asserted-by":"crossref","first-page":"25","DOI":"10.1016\/j.indcrop.2018.04.027","article-title":"Alkali lignin depolymerization under eco-friendly and cost-effective NaOH\/urea aqueous solution for fast curing bio-based phenolic resin","volume":"120","author":"Li","year":"2018","journal-title":"Ind. Crop. Prod."},{"key":"ref_46","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1016\/j.apcatb.2009.12.010","article-title":"Influence of alkali carbonates on benzyl phenyl ether cleavage pathways in superheated water","volume":"95","author":"Roberts","year":"2010","journal-title":"Appl. Catal. B"},{"key":"ref_47","doi-asserted-by":"crossref","first-page":"3888","DOI":"10.1039\/C5RA24742J","article-title":"Promotional effect of Fe on the performance of supported Cu catalyst for ambient pressure hydrogenation of furfural","volume":"6","author":"Manikandan","year":"2016","journal-title":"RSC Adv."},{"key":"ref_48","doi-asserted-by":"crossref","first-page":"175","DOI":"10.1016\/j.catcom.2016.07.003","article-title":"Effect of impregnation sequence on performance of SiO2 supported Cu-Fe catalysts for higher alcohols synthesis from syngas","volume":"84","author":"Sun","year":"2016","journal-title":"Catal. Commun."},{"key":"ref_49","doi-asserted-by":"crossref","first-page":"4385","DOI":"10.1039\/c2cc37416a","article-title":"The role of copper in catalytic performance of a Fe-Cu-Al-O catalyst for water gas shift reaction","volume":"39","author":"Ye","year":"2013","journal-title":"Chem. Commun."},{"key":"ref_50","doi-asserted-by":"crossref","first-page":"1749","DOI":"10.1039\/C9SE00240E","article-title":"FeS2\/carbon hybrids on carbon cloth: A highly efficient and stable counter electrode for dye-sensitized solar cells","volume":"3","author":"Li","year":"2019","journal-title":"Sustain. Energy Fuels"},{"key":"ref_51","doi-asserted-by":"crossref","first-page":"2806","DOI":"10.1021\/la9815446","article-title":"Correlation of relative X-ray photoelectron spectroscopy shake-up intensity with CuO particle size","volume":"15","author":"Chusuei","year":"1999","journal-title":"Langmuir"},{"key":"ref_52","doi-asserted-by":"crossref","first-page":"158","DOI":"10.1186\/1752-153X-6-158","article-title":"Selective Iron(III) ion uptake using CuO-TiO2 nanostructure by inductively coupled plasma-optical emission spectrometry","volume":"6","author":"Rahman","year":"2012","journal-title":"Chem Cent. J."},{"key":"ref_53","doi-asserted-by":"crossref","first-page":"2435","DOI":"10.1039\/b000943l","article-title":"Spectroscopic characterisation of Cu-Al2O3 catalysts for selective catalytic reduction of NO with propane","volume":"2","author":"Shimaizu","year":"2000","journal-title":"PCCP"},{"key":"ref_54","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1016\/j.ijggc.2008.06.002","article-title":"Chemical-looping with oxygen uncoupling for combustion of solid fuels","volume":"3","author":"Mattisson","year":"2009","journal-title":"Int. J. Greenh. Gas. Control."},{"key":"ref_55","doi-asserted-by":"crossref","first-page":"31828","DOI":"10.1039\/C9RA05172D","article-title":"A noble bimetal oxysulfide CuVOS catalyst for highly efficient catalytic reduction of 4-nitrophenol and organic dyes","volume":"9","author":"Sun","year":"2019","journal-title":"RSC Adv."},{"key":"ref_56","doi-asserted-by":"crossref","first-page":"173","DOI":"10.1021\/ef401487x","article-title":"Analysis on Chemical Reaction Kinetics of CuO\/SiO2 Oxygen Carriers for Chemical Looping Air Separation","volume":"28","author":"Song","year":"2014","journal-title":"Energy Fuels"},{"key":"ref_57","doi-asserted-by":"crossref","unstructured":"Liang, Z., Qin, W., and Dong, C. (2017). Experimental and Theoretical Study of the Interactions between Fe2O3\/Al2O3 and CO. Energies, 10.","DOI":"10.3390\/en10050598"},{"key":"ref_58","doi-asserted-by":"crossref","first-page":"283","DOI":"10.1016\/j.micromeso.2003.09.020","article-title":"Additional acid site on HZSM-5 treated with basic and acidic solutions as detected by temperature-programmed desorption of ammonia","volume":"66","author":"Matsuura","year":"2003","journal-title":"Microporous Mesoporous Mater."},{"key":"ref_59","doi-asserted-by":"crossref","first-page":"8067","DOI":"10.1021\/j100084a025","article-title":"Microcalorimetric and Infrared Spectroscopic Studies of. gamma.-Al2O3 Modified by Basic Metal Oxides","volume":"98","author":"Shen","year":"1994","journal-title":"J. Phys. Chem."},{"key":"ref_60","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1016\/0144-2449(94)90147-3","article-title":"Derivation of new theoretical equation for temperature-programmed desorption of ammonia with freely occurring readsorption","volume":"10","author":"Sawa","year":"1990","journal-title":"Zeolites"},{"key":"ref_61","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1016\/j.fuproc.2015.12.019","article-title":"Effect of solvent on hydrothermal oxidation depolymerization of lignin for the production of monophenolic compounds","volume":"144","author":"Ouyang","year":"2016","journal-title":"Fuel Process. Technol."},{"key":"ref_62","doi-asserted-by":"crossref","first-page":"18204","DOI":"10.1039\/C5RA25954A","article-title":"Production of phenolics via photocatalysis of ball milled lignin\u2013TiO2 mixtures in aqueous suspension","volume":"6","author":"Nair","year":"2016","journal-title":"RSC Adv."},{"key":"ref_63","first-page":"253265","article-title":"Routes of degradation of \u03b2-O-4 syringyl and guaiacyl lignin model compounds during photobleaching processes","volume":"156","author":"Machado","year":"2003","journal-title":"J. Photochem. Photobiol. A Chem."},{"key":"ref_64","doi-asserted-by":"crossref","first-page":"4596","DOI":"10.1002\/slct.201600758","article-title":"Selective Lignin Oxidation towards Vanillin in Phenol Media","volume":"1","author":"Luo","year":"2016","journal-title":"ChemistrySelect"},{"key":"ref_65","doi-asserted-by":"crossref","first-page":"8692","DOI":"10.1016\/j.jhazmat.2006.06.001","article-title":"Removal of salicylic acid on perovskite-type oxide LaFeO3 catalyst in catalytic wet air oxidation process","volume":"139","author":"Yang","year":"2007","journal-title":"J. Hazard. Mater."},{"key":"ref_66","doi-asserted-by":"crossref","first-page":"189","DOI":"10.1080\/02773819508009507","article-title":"Catalytic Mechanism of Cu2+ and Fe3+ in Alkaline O2 Oxidation of Lignin","volume":"15","author":"Wu","year":"1995","journal-title":"J. Wood Chem. Technol."},{"key":"ref_67","doi-asserted-by":"crossref","first-page":"71","DOI":"10.1385\/ABAB:91-93:1-9:71","article-title":"Production of oxychemicals from precipitated hardwood lignin","volume":"91","author":"Xiang","year":"2001","journal-title":"Appl. Biochem. Biotechnol."},{"key":"ref_68","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.rser.2014.05.001","article-title":"Renewable and, Palm oil-based biofuels and sustainability in southeast Asia: A review of Indonesia, Malaysia, and Thailand","volume":"37","author":"Mukherjee","year":"2014","journal-title":"Renew. Sustain. Energy Rev."},{"key":"ref_69","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.catcom.2012.11.006","article-title":"Unprecedented oxidative properties of mesoporous silica materials: Towards microwave-assisted oxidation of lignin model compounds","volume":"31","author":"Badamali","year":"2013","journal-title":"Catal. Commun."},{"key":"ref_70","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1016\/j.cattod.2017.05.048","article-title":"Investigation on the cleavage of \u03b2-O-4 linkage in dimeric lignin model compound over nickel catalysts supported on ZnO-Al2O3 composite oxides with varying Zn\/Al ratios","volume":"298","author":"Xu","year":"2017","journal-title":"Catal. Today"},{"key":"ref_71","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1016\/j.jcat.2011.03.030","article-title":"Bifunctional transalkylation and hydrodeoxygenation of anisole over a Pt\/HBeta catalyst","volume":"281","author":"Zhu","year":"2011","journal-title":"J. Catal."},{"key":"ref_72","doi-asserted-by":"crossref","first-page":"14283","DOI":"10.1021\/jp057332g","article-title":"Catalytic Hydrodeoxygenation of Methyl-Substituted Phenols:\u2009 Correlations of Kinetic Parameters with Molecular Properties","volume":"110","author":"Massoth","year":"2006","journal-title":"J. Phys. Chem. B"},{"key":"ref_73","doi-asserted-by":"crossref","first-page":"592","DOI":"10.1016\/j.apcatb.2017.08.009","article-title":"Selective conversion of guaiacol to substituted alkylphenols in supercritical ethanol over MoO3","volume":"219","author":"Cui","year":"2017","journal-title":"Appl. Catal. B"},{"key":"ref_74","doi-asserted-by":"crossref","first-page":"2764","DOI":"10.1039\/C8RA07962E","article-title":"Highly selective conversion of guaiacol to tert-butylphenols in supercritical ethanol over a H2WO4 catalyst","volume":"9","author":"Mai","year":"2019","journal-title":"RSC Adv."}],"container-title":["Molecules"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1420-3049\/26\/24\/7444\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T07:43:39Z","timestamp":1760168619000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1420-3049\/26\/24\/7444"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,12,8]]},"references-count":74,"journal-issue":{"issue":"24","published-online":{"date-parts":[[2021,12]]}},"alternative-id":["molecules26247444"],"URL":"https:\/\/doi.org\/10.3390\/molecules26247444","relation":{},"ISSN":["1420-3049"],"issn-type":[{"value":"1420-3049","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,12,8]]}}}