{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,14]],"date-time":"2026-10-14T14:34:49Z","timestamp":1791988489654,"version":"4.4.0"},"reference-count":41,"publisher":"MDPI AG","issue":"1","license":[{"start":{"date-parts":[[2020,1,5]],"date-time":"2020-01-05T00:00:00Z","timestamp":1578182400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"the National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["31770621"],"award-info":[{"award-number":["31770621"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100011270","name":"State Key Laboratory of Pulp and Paper Engineering","doi-asserted-by":"publisher","award":["2016TS03, 201836"],"award-info":[{"award-number":["2016TS03, 201836"]}],"id":[{"id":"10.13039\/501100011270","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Guangdong Province Science Foundation","award":["2017B090903003"],"award-info":[{"award-number":["2017B090903003"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Polymers"],"abstract":"<jats:p>\u03b3-valerolactone (GVL)\/H2O\/acid solvent mixtures has been used in chemical pretreatment of lignocellulosic biomass, it was claimed that GVL lignins were structurally close to proto (native) lignins, or having low molecular weight with narrow polydispersity, however, the structural changes of GVL lignins have not been investigated. In this study, \u03b2-O-4 (\u03b2-aryl ether, GG), \u03b2-5 (phenylcoumaran), and \u03b2-\u03b2 (resinol) lignin model compounds were treated by an acidic GVL-H2O solvent system, a promising pretreatment of lignocellulose for biomass utilization, to investigate the structural changes possibly related to the lignin involved. NMR characterization of the products isolated from the treated GG indicated that a phenyl dihydrobenzofuran, having typical C-H correlations at \u03b4C\/\u03b4H 50.74\/4.50 and 93.49\/4.60 ppm in its HSQC spectrum, was produced from GG. In the pretreatment, the released formaldehyde from GG reacted fast with GG to form a novel 1,3-dioxane intermediate whose characteristic HSQC signals were: \u03b4C\/\u03b4H 94.15\u201394.48\/4.81\u20135.18 ppm and 80.82\u201383.34\/4.50\u20134.94 ppm. The \u03b2-5 model, dihydrodehydrodiconiferyl alcohol, was converted into phenylcoumarone and stilbene having benzaldehyde that resulted from the allyl alcohol side chain. The \u03b2-\u03b2 model, syringaresinol, was isomerized to form a mixture of syringaresinol, epi-, and dia-syringaresinol although being degraded slightly.<\/jats:p>","DOI":"10.3390\/polym12010116","type":"journal-article","created":{"date-parts":[[2020,1,6]],"date-time":"2020-01-06T03:48:48Z","timestamp":1578282528000},"page":"116","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":18,"title":["Revealing Structural Modifications of Lignin in Acidic \u03b3-Valerolactone-H2O Pretreatment"],"prefix":"10.3390","volume":"12","author":[{"given":"Suxiang","family":"Li","sequence":"first","affiliation":[{"name":"State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, 381 Wushan Rd., Tianhe District, Guangzhou 510640, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chengke","family":"Zhao","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, 381 Wushan Rd., Tianhe District, Guangzhou 510640, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fengxia","family":"Yue","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, 381 Wushan Rd., Tianhe District, Guangzhou 510640, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fachuang","family":"Lu","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, 381 Wushan Rd., Tianhe District, Guangzhou 510640, China"},{"name":"Guangdong Engineering Research Center for Green Fine Chemicals, Guangzhou 510640, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,1,5]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1246843","DOI":"10.1126\/science.1246843","article-title":"Lignin valorization: Improving lignin processing in the biorefinery","volume":"344","author":"Ragauskas","year":"2014","journal-title":"Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"3552","DOI":"10.1021\/cr900354u","article-title":"The catalytic valorization of lignin for the production of renewable chemicals","volume":"110","author":"Zakzeski","year":"2010","journal-title":"Chem. Rev."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"181","DOI":"10.1039\/C3GC41752B","article-title":"Understanding the chemical transformations of lignin during ionic liquid pretreatment","volume":"16","author":"Wen","year":"2014","journal-title":"Green Chem."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"21","DOI":"10.1016\/j.biortech.2015.08.102","article-title":"Organic solvent pretreatment of lignocellulosic biomass for biofuels and biochemicals: A review","volume":"199","author":"Zhang","year":"2016","journal-title":"Bioresour. Technol."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"6540","DOI":"10.1038\/ncomms7540","article-title":"High performing and stable supported nano-alloys for the catalytic hydrogenation of levulinic acid to \u03b3-valerolactone","volume":"6","author":"Luo","year":"2015","journal-title":"Nat. Commun."},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"277","DOI":"10.1126\/science.1246748","article-title":"Nonenzymatic sugar production from biomass using biomass-derived \u03b3-valerolactone","volume":"343","author":"Luterbacher","year":"2014","journal-title":"Science"},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"73","DOI":"10.1002\/cssc.201402821","article-title":"Advanced biorefinery based on the fractionation of biomass in \u03b3-valerolactone and water","volume":"8","author":"Fang","year":"2015","journal-title":"ChemSusChem"},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"90","DOI":"10.1016\/j.biortech.2017.01.041","article-title":"Valorization of bamboo by \u03b3-valerolactone\/acid\/water to produce digestible cellulose, degraded sugars and lignin","volume":"230","author":"Li","year":"2017","journal-title":"Bioresour. Technol."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"12124","DOI":"10.1021\/acssuschemeng.8b02475","article-title":"Understanding the distribution and structural feature of eucalyptus lignin isolated by \u03b3-valerolactone\/water\/acid system","volume":"6","author":"Li","year":"2018","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"70","DOI":"10.1016\/j.biortech.2018.03.141","article-title":"Efficient degradation of lignin in raw wood via pretreatment with heteropoly acids in \u03b3-valerolactone\/water","volume":"261","author":"Zhang","year":"2018","journal-title":"Bioresour. Technol."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"889","DOI":"10.3891\/acta.chem.scand.25-0889","article-title":"Acid degradation of lignin IV: Analysis of lignin acidolysis products by gas chromatography, using trimethylsilyl derivatives","volume":"25","author":"Lundquist","year":"1971","journal-title":"Acta Chem. Scand."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"756","DOI":"10.3891\/acta.chem.scand.25-0756","article-title":"Acid degradation of lignin VI: Formation of methanol","volume":"25","author":"Lundquist","year":"1971","journal-title":"Acta Chem. Scand."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"2005","DOI":"10.3891\/acta.chem.scand.26-2005","article-title":"Acid degradation of lignin part VII: The cleavage of ether bonds","volume":"26","author":"Lundquist","year":"1972","journal-title":"Acta Chem. Scand."},{"key":"ref_14","first-page":"216","article-title":"Chemical structures of sulfuric acid lignin II: Chemical structures of condensation products from arylglycerol-\u03b2-aryl ether type structures","volume":"27","author":"Yasuda","year":"1981","journal-title":"Mokuzai Gakkaishi"},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"223","DOI":"10.1080\/02773818308085161","article-title":"Formation of C6C2-enol ethers in the acid-catalyzed hydrolysis of erythro-veratrylglycerol-\u03b2-(2-methoxyphenyl) ether","volume":"3","author":"Hoo","year":"1983","journal-title":"J. Wood Chem. Technol."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"269","DOI":"10.1080\/02773811003675288","article-title":"Revisiting the mechanism of \u03b2-o-4 bond cleavage during acidolysis of lignin. Part 2: Detailed reaction mechanism of a non-phenolic C6-C2 type model compound","volume":"30","author":"Yokoyama","year":"2010","journal-title":"J. Wood Chem. Technol."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"48","DOI":"10.3891\/acta.chem.scand.42b-0048","article-title":"On the acidolytic cleavage of arylglycerol \u03b2-aryl ethers","volume":"B42","author":"Karlsson","year":"1988","journal-title":"Acta Chem.Scand."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"889","DOI":"10.3891\/acta.chem.scand.24-0889","article-title":"Acid degradation of lignin II: Separation and identification of low molecular weight phenols","volume":"24","author":"Lundquist","year":"1970","journal-title":"Acta Chem. Scand."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1515\/HF.1999.007","article-title":"Acid reactions of lignin models of \u03b2-5 type","volume":"53","author":"Li","year":"1999","journal-title":"Holzforschung"},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"13","DOI":"10.3891\/acta.chem.scand.17-0013","article-title":"Spectrochemical estimation of phenylcoumaran elements in lignin","volume":"17","author":"Adler","year":"1963","journal-title":"Acta Chem. Scand."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"2199","DOI":"10.3891\/acta.chem.scand.25-2199","article-title":"Acid degradation of lignin V: Degradation products related to the phenylcoumaran type of structure","volume":"25","author":"Lundquist","year":"1971","journal-title":"Acta Chem. Scand."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"2657","DOI":"10.1039\/C5EE01322D","article-title":"Lignin monomer production integrated into the \u03b3-valerolactone sugar platform","volume":"8","author":"Luterbacher","year":"2015","journal-title":"Energ. Environ. Sci."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"1067","DOI":"10.1039\/B416699J","article-title":"Easy synthesis of beta-o-4 type lignin related polymers","volume":"3","author":"Kishimoto","year":"2005","journal-title":"Org. Biomol. Chem."},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"107","DOI":"10.1039\/B918179B","article-title":"Synthesis of dihydrodehydrodiconiferyl alcohol: The revised structure of lawsonicin","volume":"8","author":"Meng","year":"2010","journal-title":"Org. Biomol. Chem."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"1224","DOI":"10.3891\/acta.chem.scand.51-1224","article-title":"Synthesis of lignin models of beta-5 type","volume":"51","author":"Li","year":"1997","journal-title":"Acta Chem. Scand."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"5549","DOI":"10.1021\/acscatal.8b01235","article-title":"The biocatalytic synthesis of syringaresinol from 2,6-dimethoxy-4-allylphenol in one-pot using a tailored oxidase\/peroxidase system","volume":"8","author":"Habib","year":"2018","journal-title":"ACS Catal."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"329","DOI":"10.1126\/science.aaf7810","article-title":"Formaldehyde stabilization facilitates lignin monomer production during biomass depolymerization","volume":"354","author":"Shuai","year":"2016","journal-title":"Science"},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"1837","DOI":"10.1021\/acssuschemeng.7b03218","article-title":"Role of substituents in the solid acid-catalyzed cleavage of the \u03b2-o-4 linkage in lignin models","volume":"6","author":"Fraile","year":"2018","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_29","first-page":"484","article-title":"Chemical structures of sulfuric acid lignin III: Reaction of arylglycerol-\u03b2-aryl ether with five percent sulfuric acid","volume":"27","author":"Ito","year":"1981","journal-title":"Mokuzai Gakkaishi"},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1515\/hfsg.1987.41.1.59","article-title":"Chemical structures of sulfuric acid lignin pt.X.* reaction of syringylglycerol-\u03b2-syringyl ether and condensation of syringyl nucleus with guaiacyl lignin model compounds in sulfuric acid","volume":"41","author":"Yasuda","year":"1987","journal-title":"Holzforschung"},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"472","DOI":"10.1021\/sc400384w","article-title":"A mechanistic investigation of acid-catalyzed cleavage of aryl-ether linkages: Implications for lignin depolymerization in acidic environments","volume":"2","author":"Sturgeon","year":"2014","journal-title":"ACS Sustain. Chem. Eng."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"11872","DOI":"10.1002\/anie.201408359","article-title":"Solvent effects in acid-catalyzed biomass conversion reactions","volume":"53","author":"Mellmer","year":"2014","journal-title":"Angew. Chem. Int. Ed. Engl."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"11","DOI":"10.1080\/02773818108085091","article-title":"Kinetics of hydrolysis of erythro-guaiacylglycerol \u03b2-(2-methoxyphenyl) ether and its veratryl analogue using HCl and aluminum chloride as catalysts","volume":"1","author":"Sarkanen","year":"1981","journal-title":"J.Wood Chem. Technol."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"849","DOI":"10.1021\/ie101884h","article-title":"Hydrolytic cleavage of \u03b2-o-4 ether bonds of lignin model compounds in an ionic liquid with metal chlorides","volume":"50","author":"Jia","year":"2011","journal-title":"Ind. Eng. Chem. Res."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"1078","DOI":"10.1002\/cssc.201000112","article-title":"Cleaving the \u03b2-o-4 bonds of lignin model compounds in an acidic ionic liquid, 1-H-3-methylimidazolium chloride: An optional strategy for the degradation of lignin","volume":"3","author":"Jia","year":"2010","journal-title":"ChemSusChem"},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"164","DOI":"10.1515\/HF.2008.037","article-title":"Revisiting the mechanism of \u03b2-o-4 bond cleavage during acidolysis of lignin. Part 1: Kinetics of the formation of enol ether from non-phenolic C6-C2 type model compounds","volume":"62","author":"Yokoyama","year":"2008","journal-title":"Holzforschung"},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"219","DOI":"10.1007\/s10086-010-1166-6","article-title":"Revisiting the mechanism of \u03b2-o-4 bond cleavage during acidolysis of lignin IV: Dependence of acidolysis reaction on the type of acid","volume":"57","author":"Imai","year":"2011","journal-title":"J.Wood Sci."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"625","DOI":"10.1515\/HF.2001.102","article-title":"Liquefaction mechanism of \u03b2-o-4 lignin model compound in the presence of phenol under acid catalysis part 2. Reaction behavior and pathways","volume":"55","author":"Lin","year":"2001","journal-title":"Holzforschung"},{"key":"ref_39","doi-asserted-by":"crossref","first-page":"617","DOI":"10.1515\/HF.2001.101","article-title":"Liquefaction mechanism of \u03b2-o-4 lignin model compound in the presence of phenol under acid catalysis part 1. Identification of the reaction products","volume":"55","author":"Lin","year":"2001","journal-title":"Holzforschung"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"629","DOI":"10.1002\/jccs.199800095","article-title":"Lignans and kauranes from the stems of annona cherimola","volume":"45","author":"Chen","year":"1998","journal-title":"J. Chin. Chem. Soc."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"863","DOI":"10.1021\/np970348g","article-title":"Chemical constituents from cassytha filiformis II","volume":"61","author":"Chang","year":"1998","journal-title":"J.Nat. Prod."}],"container-title":["Polymers"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2073-4360\/12\/1\/116\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,13]],"date-time":"2025-10-13T13:18:53Z","timestamp":1760361533000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2073-4360\/12\/1\/116"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,1,5]]},"references-count":41,"journal-issue":{"issue":"1","published-online":{"date-parts":[[2020,1]]}},"alternative-id":["polym12010116"],"URL":"https:\/\/doi.org\/10.3390\/polym12010116","relation":{},"ISSN":["2073-4360"],"issn-type":[{"value":"2073-4360","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,1,5]]}}}