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1. Towards a sustainable bio-fuels production from lignocellulosic bio-oils: Influence of operating conditions on the hydrodeoxygenation of guaiacol over a Mo2C/CNF catalyst

Author:
Remón, Javier; Ochoa, Elba; Foguet, Carlos; Pinilla, José Luis; Suelves, Isabel
Source:
Fuel processing technology 2019 v.191 pp. 111-120
ISSN:
0378-3820
Subject:
guaiacol,   etc   ; biofuels; catalysts; hydrogen; lignocellulose; molecular weight; temperature; thermodynamics;     Show all 8 Subjects
Abstract:
... This work firstly provides a thorough insight into the effects of the operating conditions (catalyst loading, initial H2 pressure temperature, reaction time, H2/guaiacol ratio and liquid reaction volume) on the hydrodeoxygenation (HDO) of guaiacol over a Mo2C/CNF catalyst. Under the operating condition tested, gas and solid formation was negligible and guaiacol was primary converted to different l ...
DOI:
10.1016/j.fuproc.2019.04.008

2. Phenolics isolation from bio-oil using the metal–organic framework MIL-53(Al) as a highly selective adsorbent

Author:
Jia, Chunmei; Bueken, Bart; Cirujano, Francisco G.; Van Geem, Kevin M.; De Vos, Dirk
Source:
Chemical communications 2019 v.55 no.44 pp. 6245-6248
ISSN:
1364-548X
Subject:
guaiacol,   etc   ; adsorbents; catechol; chemical reactions; coordination polymers; pyrolysis oils;     Show all 6 Subjects
Abstract:
... By using flexible metal organic frameworks such as MIL-53(Al), the selective uptake of 4-methylguaiacol was achieved from a simulated bio-oil (40 wt%). Similar high uptake capacity of phenolics (27 wt%) was observed from a real pyrolysis bio-oil, with good selectivity towards a variety of phenolics, e.g. guaiacol, 4-methylguaiacol and catechol. ...
DOI:
10.1039/c9cc02177a

3. Mechanistic details of CO bond activation in and H-addition to guaiacol at water-Ru cluster interfaces

Author:
Shangguan, Junnan; Pfriem, Niklas; Chin, Ya-Huei (Cathy)
Source:
Journal of catalysis 2019 v.370 pp. 186-199
ISSN:
0021-9517
Subject:
guaiacol,   etc   ; catalytic activity; cleavage (chemistry); cyclohexanones; hydrogen; phenol;     Show all 6 Subjects
Abstract:
... Catalytic pathways of guaiacol and hydrogen (H2) reactions on dispersed Ru clusters in the aqueous medium and the associated kinetic requirements for COCH3 bond cleavage and H-addition steps are established based on kinetic and isotopic investigations. Time-dependent kinetic measurements in a gradientless semi-batch reactor reveal that guaiacol reacts with H2 via two independent routes of COCH3 bo ...
DOI:
10.1016/j.jcat.2018.11.036

4. Hydrodeoxygenation of phenols, acids, and ketones as model bio-oil for hydrocarbon fuel over Ni-based catalysts modified by Al, La and Ga

Author:
Li, Zhiyu; Jiang, Enchen; Xu, Xiwei; Sun, Yan; Tu, Ren
Source:
Renewable energy 2020 v.146 pp. 1991-2007
ISSN:
0960-1481
Subject:
guaiacol,   etc   ; acetic acid; acidity; alkanes; aluminum; benzene; biofuels; biomass; catalysts; condensation reactions; demethylation; heat; hydrogenation; isomerization; ketones; liquids; models; nickel; oxides;     Show all 19 Subjects
Abstract:
... The large-scale application of bio-oil has been restricted due to its high O content, strong acidity and low heat value. Therefore, the hydrodeoxygenation (HDO) of phenols, acids, and ketones as bio-oil model compounds for hydrocarbon fuel via Ni-based catalysts modified by metal oxides (Al, La and Ga) was investigated. The results showed that the hydrocarbon content was over 70.65% when the mixed ...
DOI:
10.1016/j.renene.2019.08.012

5. Effects of cooling rate on retrograded nucleation of different rice starch-aromatic molecule complexes

Author:
Ma, Rongrong; Tian, Yaoqi; Chen, Long; Cai, Canxin; Jin, Zhengyu
Source:
Food chemistry 2019 v.294 pp. 179-186
ISSN:
0308-8146
Subject:
guaiacol,   etc   ; X-ray diffraction; cooling; crystal structure; differential scanning calorimetry; enthalpy; gamma-decalactone; octenol; odors; rice;     Show all 10 Subjects
Abstract:
... The effects of cooling rate (CR) on retrograded nucleation of rice starch-aromatic molecule complexes were evaluated. Six aromatic molecules (hexanal, 1-octen-3-ol, γ-decalactone, guaiacol, 2, 3-butanedione, and 2-acetyl-1-pyrroline) were chosen to represent the typical aromas in cooked rice. Differential scanning calorimetry results showed that increased CR from 0.34 to 3.04 °C/min led to reduced ...
DOI:
10.1016/j.foodchem.2019.05.077

6. Theoretical study on the mechanisms, kinetics and ecotoxicity assessment of OH-initiated reactions of guaiacol in atmosphere and wastewater

Author:
An, Zexiu; Sun, Jianfei; Han, Dandan; Mei, Qiong; Wei, Bo; Wang, Xueyu; He, Maoxia
Source:
The Science of the total environment 2019 v.685 pp. 729-740
ISSN:
0048-9697
Subject:
guaiacol,   etc   ; aerosols; aqueous solutions; ecotoxicology; energy; formates; gases; half life; nitrogen dioxide; quinones; solvents; toxicity; wastewater;     Show all 13 Subjects
Abstract:
... The OH-initiated transformation mechanisms, kinetics and ecotoxicity assessment of guaiacol (2-methoxyphenol) in the presence of O2/NOx were investigated both in atmosphere and wastewater. The solvent effect lowers the energy barriers of initial OH-addition reactions more than H-abstraction reactions, leading to much higher addition branching ratio (Γadd) of 0.92 in aqueous solution than that of 0 ...
DOI:
10.1016/j.scitotenv.2019.06.229

7. A simple and effective strategy based on sodium gallate-exfoliated graphene for the simultaneous voltammetric determination of guaiacol and vanillin

Author:
Li, Chenchen; Fu, Ju; Tan, Xiaohong; Song, Xinjian; Li, Qunfang
Source:
Analytical methods 2019 v.11 no.32 pp. 4099-4105
ISSN:
1759-9679
Subject:
guaiacol,   etc   ; analytical methods; detection limit; dimethylformamide; electrochemistry; graphene; nanosheets; oxidation; sodium; ultrasonic treatment; vanillin;     Show all 11 Subjects
Abstract:
... High concentration graphene nanosheets were easily prepared through simple liquid-phase exfoliation of graphite powder in N,N-dimethylformamide with the assistance of sodium gallate (SG). The concentration of the obtained graphene dispersion reached 2.0 mg mL⁻¹ only after three hours of ultrasonic treatment. Sodium gallate-exfoliated graphene nanosheets (SG-GNs) showed remarkable signal enhancemen ...
DOI:
10.1039/c9ay01018a

8. Assessment of vine-shoots in a model wines as enological additives

Author:
Cristina, Cebrián-Tarancón; Rosario, Sánchez-Gómez; Miguel, Carot José; Amaya, Zalacain; Alonso, Gonzalo L.; Rosario, Salinas M.
Source:
Food chemistry 2019 v.288 pp. 86-95
ISSN:
0308-8146
Subject:
guaiacol,   etc   ; additives; ellagic acid; maceration; models; oak chips; odors; toasting; vanillin; wines;     Show all 10 Subjects
Abstract:
... For the first time, the possibility of using vine-shoots as enological additives, similar to oak chips, is proposed. Their volatile and phenolic compounds contribution to a model wine was studied. Variables such as vine-shoot vinifera (Airén and Cencibel), size (chip and granule), toasting (toasted and non-toasted), dosage (4 and 12 g/L) and maceration time (1, 7, 21, 35 and 120 days) were tested. ...
DOI:
10.1016/j.foodchem.2019.02.075

9. Study on the effect of condensing temperature of walnut shells pyrolysis vapors on the composition and properties of bio-oil

Author:
Wang, Chu; Luo, Zejun; Diao, Rui; Zhu, Xifeng
Source:
Bioresource technology 2019 v.285 pp. 121370
ISSN:
0960-8524
Subject:
guaiacol,   etc   ; acetic acid; biofuels; condensation (phase transition); furfural; pyrolysis; temperature; vapors; walnut hulls;     Show all 9 Subjects
Abstract:
... The effect of condensing temperature on composition of bio-oil obtained via fractional condensation was investigated by pyrolysis-condensation experiments of walnut shells at condensing temperatures from 290 K to 370 K. The condensing efficiency of the first stage condenser decreased from 0.59 to 0.12 with increasing temperature. Moisture of bio-oil decreased from 40% to 5%, but the C/O ratio incr ...
DOI:
10.1016/j.biortech.2019.121370

10. Winemaking with vine-shoots. Modulating the composition of wines by using their own resources

Author:
Cebrián-Tarancón, Cristina; Sánchez-Gómez, Rosario; Cabrita, María João; García, Raquel; Zalacain, Amaya; Alonso, Gonzalo L.; Salinas, M. Rosario
Source:
Food research international 2019 v.121 pp. 117-126
ISSN:
0963-9969
Subject:
guaiacol,   etc   ; Vitis vinifera; chemical composition; fermentation; odors; red wines; vanillin; white wines; winemaking;     Show all 9 Subjects
Abstract:
... Vine-shoots from two important Vitis vinifera, Airén and Cencibel, have been prepared in two different formats (chip and granule) and added (12 g/L) in their own wines in different winemaking steps. Results have shown significant differences depending in all conditions tested, and wine chemical composition was modulated while in contact with vine-shoots. Compounds such as trans-resveratrol, increa ...
DOI:
10.1016/j.foodres.2019.03.032

11. Hydrothermal base catalysed treatment of Kraft lignin - time dependent analysis and a techno-economic evaluation for carbon fibre applications

Author:
Otromke, Malte; Shuttleworth, Peter S.; Sauer, Jörg; White, Robin J.
Source:
Bioresource technology reports 2019 v.6 pp. 241-250
ISSN:
2589-014X
Subject:
guaiacol,   etc   ; carbon fibers; catechol; energy; hot water treatment; lignin; molecular weight; prices; thermal stability; vanillin;     Show all 10 Subjects
Abstract:
... The hydrothermal base-catalysed treatment of industrial Kraft lignin (KL) is investigated as a basis for production of a sustainable carbon fibre precursor, with a focus on the time-dependent evolution and impact on precursor properties. Hydrothermal treatment was performed at T = 300 °C and p = 180 bar, with the retention time (tret) varied between 8, 12, 16, 20, and 24 mins. Molecular weight dis ...
DOI:
10.1016/j.biteb.2019.03.008

12. Key odorants in peated malt whisky and its differentiation from other whisky types using profiling of flavor and volatile compounds

Author:
Jeleń, Henryk H.; Majcher, Małgorzata; Szwengiel, Artur
Source:
Lebensmittel-Wissenschaft + [i.e. und] Technologie 2019 v.107 pp. 56-63
ISSN:
0023-6438
Subject:
guaiacol,   etc   ; flavor; gas chromatography; malt; models; odor compounds; olfactometry; solid phase microextraction; whisky;     Show all 9 Subjects
Abstract:
... Key odorants of peated single malt whisky were identified using gas chromatography – olfactometry (GC-O). Twenty compounds were identified with FD (Flavor Dilution) values ranging from 8 to 2048 and 8 of them were volatile phenols. The compounds with the highest FD were 2-methoxyphenol (guaiacol), 4-ethyl-2-methoxyphenol (4-ethylguaiacol), 4-methylphenol, 4-vinyl-2-methoxyphenol (4-vinylguaiacol) ...
DOI:
10.1016/j.lwt.2019.02.070

13. Pyrolysis of Acidic Ionic Liquid 1-Sulfonic Acid Butyl-3-methylimidazolium Trifluoromethanesulfonate-Treated Lignin for Phenolics Production

Author:
Lei, Zhiping; Dong, Lin; Hu, Zhiquan; Li, Zhanku; Yan, Jingchong; Shui, Hengfu; Kang, Shigang; Wang, Zhicai; Ren, Shibiao; Pan, Chunxiu
Source:
Energy & fuels 2019 v.33 no.6 pp. 4767-4774
ISSN:
1520-5029
Subject:
guaiacol,   etc   ; Fourier transform infrared spectroscopy; fuels; ionic liquids; lignin; phenol; pyrolysis;     Show all 7 Subjects
Abstract:
... The effect of pretreatment of lignin with acidic ionic liquid 1-sulfonic acid butyl-3-methylimidazolium trifluoromethanesulfonate ([B(SO₃H)mim]OTf) on lignin pyrolysis behavior and the distribution of phenolics in tar were investigated in this paper. It is found that [B(SO₃H)mim]OTf pretreatment under mild conditions (such as 50 °C) leads to an increase in lignin pyrolysis tar yield of 11.8% and a ...
DOI:
10.1021/acs.energyfuels.9b00200

14. Effect of Oxalate and Sulfate on Iron-Catalyzed Secondary Brown Carbon Formation

Author:
Al Nimer, Aseel; Rocha, Laura; Rahman, Mohammad A.; Nizkorodov, Sergey A.; Al-Abadleh, Hind A.
Source:
Environmental science & technology 2019 v.53 no.12 pp. 6708-6717
ISSN:
1520-5851
Subject:
guaiacol,   etc   ; aerosols; anions; carbon; catechol; color; hydrodynamics; iron; ligands; oxalates; pH; particle size; polymerization; polymers; sulfates;     Show all 15 Subjects
Abstract:
... Oxalate and sulfate are ubiquitous components of ambient aerosols with a high complexation affinity to iron. However, their effect on iron-driven secondary brown carbon formation in solution from soluble aromatic and aliphatic reagents was not studied. We report masses and hydrodynamic particle sizes of insoluble particles formed from the dark aqueous phase reaction of catechol, guaiacol, fumaric, ...
DOI:
10.1021/acs.est.9b00237

15. Aromatics from lignin through ultrafast reactions in water

Author:
Abad-Fernández, Nerea; Pérez, Eduardo; Cocero, María José
Source:
Green chemistry 2019 v.21 no.6 pp. 1351-1360
ISSN:
1463-9270
Subject:
guaiacol,   etc   ; condensation reactions; depolymerization; green chemistry; hot water treatment; lignin; oils; vanillin; waste liquors;     Show all 9 Subjects
Abstract:
... Nowadays, the valorization of lignin, the major natural source of aromatics, is a challenge for the scientific community. In this study, kraft lignin was effectively converted into aromatic monomers via ultrafast depolymerization in hot and pressurized water. At reaction times below 500 ms, it was possible to avoid char formation originating from undesirable condensation reactions by accurately co ...
DOI:
10.1039/c8gc03989e

16. Accumulation of volatile phenol glycoconjugates in grapes following grapevine exposure to smoke and potential mitigation of smoke taint by foliar application of kaolin

Author:
van der Hulst, Lieke; Munguia, Pablo; Culbert, Julie A.; Ford, Christopher M.; Burton, Rachel A.; Wilkinson, Kerry L.
Source:
Planta 2019 v.249 no.3 pp. 941-952
ISSN:
0032-0935
Subject:
guaiacol,   etc   ; Vitis; cresols; foliar application; fruits; glycoconjugates; grapes; kaolin; odors; phenol; prescribed burning; reflectance; smoke; taint;     Show all 14 Subjects
Abstract:
... MAIN CONCLUSION: The accumulation of volatile phenol glycoconjugates in smoke-exposed grapes was monitored following grapevine exposure to smoke, with different glycoconjugate profiles observed for fruit sampled 1 and 7 days after smoke exposure, and at maturity. Foliar application of kaolin reduced the concentration of volatile phenol glycoconjugates in smoke-exposed fruit, but efficacy depended ...
DOI:
10.1007/s00425-018-03079-x

17. Lignin oxidation with an organic peroxide and subsequent aromatic ring opening

Author:
Fernandes, Mónica R.C.; Huang, Xiaoming; Abbenhuis, Hendrikus C.L.; Hensen, Emiel J.M.
Source:
International journal of biological macromolecules 2019 v.123 pp. 1044-1051
ISSN:
0141-8130
Subject:
guaiacol,   etc   ; carbon; crosslinking; lignin; models; nuclear magnetic resonance spectroscopy; oxidation; stable isotopes; titanium;     Show all 9 Subjects
Abstract:
... The oxidation of an organosolv lignin with tert-butylhydroperoxide, initiated by titanium grafted into the lignin structure, was investigated. Titanation of reactive groups on lignin is responsible for the cross-linking of the lignin structure. IR and MAS 13C NMR spectroscopy spectra confirmed the oxidation of the lignin structure and other pronounced structural changes. A study with guaiacol as a ...
DOI:
10.1016/j.ijbiomac.2018.11.105

18. Highly selective catalytic conversion of lignin-derived phenolic compounds to cycloalkanes over a hierarchically structured zeolite catalyst

Author:
Xiang, Mei; Wu, Dongfang
Source:
Journal of materials science 2019 v.54 no.4 pp. 2940-2959
ISSN:
0022-2461
Subject:
guaiacol,   etc   ; Lewis acids; catalysts; catalytic activity; cobalt; cyclohexanes; iron; lignin; mass transfer; models; nickel; zeolites;     Show all 12 Subjects
Abstract:
... Hierarchically structured ETS-10-supported highly dispersed Co (Co/HMETS-10) is a promising catalyst to selectively catalyse hydrodeoxygenation (HDO) of lignin-derived phenolic compounds. It is shown that almost 100% guaiacol conversion and 96.9% cyclohexane yield are achieved under mild conditions. Co/HMETS-10 exhibits much higher activity and superior reusability due to the advantageous effects ...
DOI:
10.1007/s10853-018-3057-y

19. Low temperature hydrodeoxygenation of guaiacol into cyclohexane over Ni/SiO₂ catalyst combined with Hβ zeolite

Author:
Wang, Xun; Zhu, Shanhui; Wang, Sen; He, Yue; Liu, Yang; Wang, Jianguo; Fan, Weibin; Lv, Yongkang
Source:
RSC advances 2019 v.9 no.7 pp. 3868-3876
ISSN:
2046-2069
Subject:
guaiacol,   etc   ; adsorption; aluminum; biofuels; catalysts; catalytic activity; cyclohexanes; silica; silicon; temperature; zeolites;     Show all 11 Subjects
Abstract:
... Hydrodeoxygenation (HDO) of guaiacol to cyclohexane, important for bio-oil upgrading, is usually performed at high reaction temperature (≥200 °C). In this work, low temperature transformation of guaiacol to cyclohexane was achieved at 140 °C over non-noble metal Ni/SiO₂ and various zeolites. Among zeolites tested (HUSY, HMOR, Hβ, HZSM-5, SAPO-34), Hβ zeolite exhibited superior catalytic activity d ...
DOI:
10.1039/c8ra09972c

20. Highly selective conversion of guaiacol to tert-butylphenols in supercritical ethanol over a H₂WO₄ catalyst

Author:
Mai, Fuhang; Cui, Kai; Wen, Zhe; Wu, Kai; Yan, Fei; Chen, Mengmeng; Chen, Hong; Li, Yongdan
Source:
RSC advances 2019 v.9 no.5 pp. 2764-2771
ISSN:
2046-2069
Subject:
guaiacol,   etc   ; Bronsted acids; alkylation; alkylphenols; carbon; catalysts; catechol; ethanol; ethers; tungsten oxide;     Show all 10 Subjects
Abstract:
... The conversion of guaiacol is examined at 300 °C in supercritical ethanol over a H₂WO₄ catalyst. Guaiacol is consumed completely, meanwhile, 16.7% aromatic ethers and 80.0% alkylphenols are obtained. Interestingly, tert-butylphenols are produced mainly with a high selectivity of 71.8%, and the overall selectivity of 2,6-di-tert-butylphenol and 2,6-di-tert-butyl-4-ethylphenol is as high as 63.7%. T ...
DOI:
10.1039/c8ra07962e