-
Efficient decaffeination of green coffee beans using pressure swing supercritical CO2 extraction
Peer-reviewed
Yuya Hiraga, Chinatsu Yoshida, Konomi Aoki, Masaru Watanabe
Innovative Food Science & Emerging Technologies 104 104154-104154 2025/08
Publisher:
Elsevier BV
DOI：
10.1016/j.ifset.2025.104154
ISSN：
1466-8564
-
Modeling of ionic liquid solubility in supercritical carbon dioxide + co-solvent phase predicted by ε*-modified Sanchez-Lacombe equation of state
Peer-reviewed
Yuya Hiraga, Ikuo Ushiki
Fluid Phase Equilibria 595 114417 2025/08
DOI：
10.1016/j.fluid.2025.114417
-
Experimental Liquid Densities of Red Palm Oil at Pressures up to 150 MPa from (312 to 352) K and Dynamic Viscosities at 0.1 MPa from (293 to 353) K
Peer-reviewed
Jia Lin Lee, Gun Hean Chong, Yuya Hiraga, Yoshiyuki Sato, Masaki Ota, Richard Lee Smith, Jr.
Liquids 2025/05/13
DOI：
10.3390/liquids5020013
-
Quantitative analysis of physical absorption behavior of CO2 in imidazolium-based ionic liquids containing bis(trifluoromethylsulfonyl)imide and tetrafluoroborate anion by Raman spectroscopy
Peer-reviewed
Yuya Hiraga, Yuta Takikawa, Moe Tatsushima, Masaru Watanabe
Chemical Engineering Science 307 121352 2025/03
DOI：
10.1016/j.ces.2025.121352
-
Viscosity prediction of CO2-saturated imidazolium-based ionic liquids using the ε*-modified Sanchez–Lacombe equation of state and free volume theory with a new correction term
Peer-reviewed
Ryohei Otani, Yuya Hiraga, Masaru Watanabe
Physical Chemistry Chemical Physics 27 (23) 12532-12541 2025
Publisher:
Royal Society of Chemistry (RSC)
DOI：
10.1039/d5cp01170a
ISSN：
1463-9076
eISSN：
1463-9084
-
Synthesis/separation of 5-hydroxymethylfurfural converted from fructose promoted by H2O–CO2 biphasic system with solid catalysts: Experimental and kinetic modeling approaches
Peer-reviewed
Yuya Hiraga, Kosuke Ebina, Yu Su, Masaru Watanabe, Vincent Oriez, Séverine Camy
Chemical Engineering Journal 485 149606-149606 2024/04
Publisher:
Elsevier BV
DOI：
10.1016/j.cej.2024.149606
ISSN：
1385-8947
-
Prediction of ionic liquid solubilities in supercritical CO2 + co-solvent systems using Peng–Robinson equation of state with accurate critical temperature
Peer-reviewed
Yuya Hiraga, Ikuo Ushiki.
Journal of Molecular Liquids 398 124324-124324 2024/03
Publisher:
Elsevier BV
DOI：
10.1016/j.molliq.2024.124324
ISSN：
0167-7322
-
Catalyst-free synthesis of 5-hydroxymethylfurfural from fructose by extractive reaction in supercritical CO2 – subcritical H2O two-phase system
Peer-reviewed
Vincent Oriez, Hélène Labauze, Bouchra Benjelloun-Mlayah, Thomas Deleau, Yuya Hiraga, Masaru Watanabe, Jean Stéphane Condoret, Séverine Camy
Journal of Supercritical Fluids 198 2023/07
DOI：
10.1016/j.supflu.2023.105904
ISSN：
0896-8446
-
Understanding the reaction behavior of alanine under hydrothermal conditions through a network model
Peer-reviewed
Qingxin Zheng, Keisuke Suzuki, Yuya Hiraga, Masaru Watanabe
Chemical Engineering Journal 468 143588-143588 2023/05
Publisher:
Elsevier BV
DOI：
10.1016/j.cej.2023.143588
ISSN：
1385-8947
-
Dynamic semi-batch supercritical fluid extraction model based on fundamentally thermodynamic equilibrium properties,熱力学平衡物性に基づく新しい半回分式超臨界抽出モデルの開発
Ota, M., Urabe, M., Nomura, K., Hiraga, Y., Watanabe, M., Inomata, H.
Nippon Shokuhin Kagaku Kogaku Kaishi 70 (9) 2023
DOI：
10.3136/nskkk.NSKKK-D-23-00050
ISSN：
1341-027X
-
Quantitative evaluation of enzyme-assisted supercritical CO2 extraction of natural essential oil from yuzu peel and evaluation for the functionality of the extraction residue
Peer-reviewed
Yuya Hiraga, Nanami Kise, Kota Torii, Masako Toda, Mayumi Sueyoshi, Tomotsugu Ohashi, Masaru Watanabe
KAGAKU KOGAKU RONBUNSHU 49 (5) 133-141 2023
Publisher:
Society of Chemical Engineers, Japan
DOI：
10.1252/kakoronbunshu.49.133
ISSN：
0386-216X
eISSN：
1349-9203
-
Chromatograph Calculation Method Based on Multi-Stage Binary Phase Distribution Equilibria
Peer-reviewed
Ota, M., Shuta, M., Hiraga, Y., Watanabe, M., Inomata, H.
Kagaku Kogaku Ronbunshu 49 (5) 2023
DOI：
10.1252/kakoronbunshu.49.129
ISSN：
1349-9203 0386-216X
-
High-capacity, high-power organic electrode via supercritical CO2 impregnation into activated carbon micropores
Peer-reviewed
Yuta Nakayasu, Shu Sokabe, Yuya Hiraga, Masaru Watanabe
Chemical Communications 2023
Publisher:
Royal Society of Chemistry (RSC)
DOI：
10.1039/d2cc06580k
ISSN：
1359-7345
eISSN：
1364-548X
-
Sulfonated carbon-catalyzed deamination of alanine under hydrothermal conditions
Peer-reviewed
Qingxin Zheng, Takuma Kato, Yuko Ito, Masayoshi Wagatsuma, Yuya Hiraga, Masaru Watanabe
Journal of Supercritical Fluids 175 2021/09
DOI：
10.1016/j.supflu.2021.105275
ISSN：
0896-8446
-
Application of hydrothermal leaching technology to spent LIB cathode materials with citric acid using batch-type device and flow system
Peer-reviewed
Qingxin Zheng, Kensuke Shibazaki, Tetsufumi Ogawa, Atsushi Kishita, Yuya Hiraga, Masaru Watanabe
Journal of Chemical Engineering of Japan 54 (6) 344-350 2021/06/20
DOI：
10.1252/jcej.20we182
ISSN：
0021-9592
-
Glycine-Assisted Hydrothermal Leaching of LiCoO2/LiNiO2Cathode Materials with High Efficiency and Negligible Acid Corrosion Employing Batch and Continuous Flow System
Peer-reviewed
Qingxin Zheng, Kensuke Shibazaki, Seiya Hirama, Yuta Iwatate, Atsushi Kishita, Yuya Hiraga, Yuta Nakayasu, Masaru Watanabe
ACS Sustainable Chemistry and Engineering 9 (8) 3246-3257 2021/03/01
DOI：
10.1021/acssuschemeng.0c08703
eISSN：
2168-0485
-
Continuous hydrothermal leaching of LiCoO2 cathode materials by using citric acid
Peer-reviewed
Qingxin Zheng, Kensuke Shibazaki, Tetsufumi Ogawa, Atsushi Kishita, Yuya Hiraga, Yuta Nakayasu, Masaru Watanabe
Reaction Chemistry and Engineering 5 (12) 2148-2154 2020/12
DOI：
10.1039/d0re00286k
eISSN：
2058-9883
-
Hydrothermal leaching of ternary and binary lithium-ion battery cathode materials with citric acid and the kinetic study
Peer-reviewed
Qingxin Zheng, Masaru Watanabe, Yuta Iwatate, Daiki Azuma, Kensuke Shibazaki, Yuya Hiraga, Atsushi Kishita, Yuta Nakayasu
The Journal of Supercritical Fluids 165 104990-104990 2020/07
Publisher:
Elsevier BV
DOI：
10.1016/j.supflu.2020.104990
ISSN：
0896-8446
-
Hydrothermal organic acid leaching of positive electrode material of lithium-ion batteries
Peer-reviewed
Kensuke Shibazaki, Daiki Azuma, Masaru Watanabe, Atsushi Kishita, Yuya Hiraga, Hideki Miyazaki
Kagaku Kogaku Ronbunshu 46 (5) 167-175 2020
DOI：
10.1252/kakoronbunshu.46.167
ISSN：
0386-216X
eISSN：
1349-9203
-
A precise deconvolution method to derive methane hydrate cage occupancy ratios using Raman spectroscopy
Peer-reviewed
Hiraga, Y., Sasagawa, T., Yamamoto, S., Komatsu, H., Ota, M., Tsukada, T., Smith, R.L.
Chemical Engineering Science 214 115361-115361 2020
Publisher:
Elsevier BV
DOI：
10.1016/j.ces.2019.115361
ISSN：
0009-2509
-
Hydrogen gas-free processes for single-step preparation of transition-metal bifunctional catalysts and one-pot Γ-valerolactone synthesis in supercritical CO2 -ionic liquid systems
Peer-reviewed
Haixin Guo, Yuya Hiraga, Xinhua Qi, Richard Lee Smith
Journal of Supercritical Fluids 147 263-270 2019/05
DOI：
10.1016/j.supflu.2018.11.010
ISSN：
0896-8446
-
N-formyl-stabilizing quasi-catalytic species afford rapid and selective solvent-free amination of biomass-derived feedstocks
Peer-reviewed
Hu Li, Haixin Guo, Yaqiong Su, Yuya Hiraga, Zhen Fang, Emiel J. M. Hensen, Masaru Watanabe, Richard Lee Smith
NATURE COMMUNICATIONS 10 (1) 2019/02
DOI：
10.1038/s41467-019-08577-4
ISSN：
2041-1723
-
Kinetic study of hydrothermal leaching of lithium cobalt oxide with citric acid
Peer-reviewed
Azuma, D., Aikawa, T., Hiraga, Y., Watanabe, M., Smith, R.L.
Kagaku Kogaku Ronbunshu 45 (4) 2019
DOI：
10.1252/kakoronbunshu.45.147
-
Fundamental consideration about resource conversion by high pressure fluids focusing on hydrothermal or ionic liquid processes
Peer-reviewed
Hiraga, Y., Watanabe, M.
Review of High Pressure Science and Technology/Koatsuryoku No Kagaku To Gijutsu 29 (3) 2019
DOI：
10.4131/jshpreview.29.206
-
Effect of lewis and brønsted acids on conversion of chitin monomer n-acetyl-d-glucosamine (GlcNAc) to furan derivatives in [bmim]cl ionic liquid
Peer-reviewed
Azuma, D., Yoshii, T., Watanabe, M., Hiraga, Y., Smith, R.L., Ogata, M., Osada, M.
Kagaku Kogaku Ronbunshu 45 (4) 147-157 2019
DOI：
10.1252/kakoronbunshu.45.141
-
Measurement and modeling of infinite dilution activity coefficients of organic compounds in an equimolar ionic liquid mixture of [Bmim]Cl and [Bmim][Tf <inf>2</inf> N]
Peer-reviewed
Shida, T., Hiraga, Y., Sugiyama, T., Sato, Y., Watanabe, M., Smith, R.L.
Fluid Phase Equilibria 488 72-78 2019
DOI：
10.1016/j.fluid.2019.01.028
ISSN：
0378-3812
-
Methane clathrate hydrate dissociation analyzed with Raman spectroscopy and a thermodynamic mass transfer model considering cage occupancy
Peer-reviewed
Komatsu, H., Sasagawa, T., Yamamoto, S., Hiraga, Y., Ota, M., Tsukada, T., Smith, R.L.
Fluid Phase Equilibria 489 41-47 2019
DOI：
10.1016/j.fluid.2019.02.004
ISSN：
0378-3812
eISSN：
1879-0224
-
Decomposition of Methane Hydrates Analyzed with Raman Spectroscopy and a Mass Transfer model Considering Cage Occupancy
Hiroyuki Komatsu, Takuya Sasagawa, Shinichiro Yamamoto, Yuya Hiraga, Masaki Ota, Takao Tsukada, Richard, L. Smith J
Proceedings of 8th International Symposium on Molecular Thermodynamics and Molecular Simulation 2018/09/04
-
Mechanism of Glucose Conversion into 5-Ethoxymethylfurfural in Ethanol with Hydrogen Sulfate Ionic Liquid Additives and a Lewis Acid Catalyst
Peer-reviewed
Haixin Guo, Alif Duereh, Yuya Hiraga, Xinhua Qi, Richard Lee Smith
ENERGY & FUELS 32 (8) 8411-8419 2018/08
DOI：
10.1021/acs.energyfuels.8b00717
ISSN：
0887-0624
eISSN：
1520-5029
-
Solvent Polarity of Cyclic Ketone (Cyclopentanone, Cyclohexanone): Alcohol (Methanol, Ethanol) Renewable Mixed-Solvent Systems for Applications in Pharmaceutical and Chemical Processing
Peer-reviewed
Alif Duereh, Haixin Guo, Tetsuo Honma, Yuya Hiraga, Yoshiyuki Sato, Richard Lee Smith, Hiroshi Inomata
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH 57 (22) 7331-7344 2018/06
DOI：
10.1021/acs.iecr.8b00689
ISSN：
0888-5885
-
Measurement and Correlation of High-Pressure Densities and Atmospheric Viscosities of Ionic Liquids: 1-Butyl-1-methylpyrrolidinium Bis(trifluoromethylsulfonyl)imide), 1-Allyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide, 1-Ethyl-3-methylimidazolium Tetracyanoborate, and 1-Hexyl-3-methylimidazolium Tetracyanoborate
Peer-reviewed
Yuya Hiraga, Saki Hagiwara, Yoshiyuki Sato, Richard L. Smith
Journal of Chemical and Engineering Data 63 (4) 972-980 2018/04/12
DOI：
10.1021/acs.jced.7b00773
ISSN：
1520-5134 0021-9568
-
Aspects of solvent polarity and solvent properties in developing efficient systems for processing biomass with ionic liquid mixtures and supercritical CO2
Peer-reviewed
Yuya Hiraga, Alif Duereh, Richard L. Smith
Journal of Supercritical Fluids 134 12-20 2018/04/01
DOI：
10.1016/j.supflu.2017.12.022
ISSN：
0896-8446
-
Measurement and modeling of CO2 solubility in [bmim]Cl – [bmim][Tf2N] mixed-ionic liquids for design of versatile reaction solvents
Peer-reviewed
Yuya Hiraga, Kento Koyama, Yoshiyuki Sato, Richard L. Smith
Journal of Supercritical Fluids 132 42-50 2018/02/01
DOI：
10.1016/j.supflu.2017.02.001
ISSN：
0896-8446
-
Continuous wet-extraction of hydrocarbon from botryococcus Braunii
Peer-reviewed
Masaki Ota, Yuya Hiraga, Yuichiro Hamano, Fujimaru Hishinuma, Ikuo Ushiki, Takumi Ono, Yoshiyuki Sato, Hiroshi Inomata
Kagaku Kogaku Ronbunshu 44 (2) 103-106 2018
DOI：
10.1252/kakoronbunshu.44.103
ISSN：
1349-9203 0386-216X
eISSN：
1349-9203
-
Efficient conversion of fructose into 5-ethoxymethylfurfural with hydrogen sulfate ionic liquids as co-solvent and catalyst
Peer-reviewed
Guo, H., Qi, X., Hiraga, Y., Aida, T.M., Smith, R.L.
Chemical Engineering Journal 314 508-514 2017
DOI：
10.1016/j.cej.2016.12.008
ISSN：
1385-8947
eISSN：
1873-3212
-
Perfect recycle and mechanistic role of hydrogen sulfate ionic liquids as additive in ethanol for efficient conversion of carbohydrates into 5-ethoxymethylfurfural
Peer-reviewed
Haixin Guo, Alif Duereh, Yuya Hiraga, Taku M. Aida, Xinhua Qi, Richard Lee Smith
Chemical Engineering Journal 323 287-294 2017
Publisher:
Elsevier B.V.
DOI：
10.1016/j.cej.2017.04.111
ISSN：
1385-8947
-
High pressure densities for mixed ionic liquids having different functionalities: 1-butyl-3-methylimidazolium chloride and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide
Peer-reviewed
Hiraga, Y., Koyama, K., Sato, Y., Smith, R.L.
Journal of Chemical Thermodynamics 108 7-17 2017
DOI：
10.1016/j.jct.2016.12.037
ISSN：
0021-9614
eISSN：
1096-3626
-
Measurement of high pressure densities and atmospheric pressure viscosities of alkyl phosphate anion ionic liquids and correlation with the ε∗-modified Sanchez-Lacombe equation of state
Peer-reviewed
Hiraga, Y., Goto, M., Sato, Y., Smith, R.L.
Journal of Chemical Thermodynamics 104 73-81 2017
DOI：
10.1016/j.jct.2016.09.013
ISSN：
0021-9614
eISSN：
1096-3626
-
Measurement of infinite dilution partition coefficients of isomeric benzene derivatives in [bmim][Tf2N]-CO2biphasic system and correlation with the ePC-SAFT equation of state
Peer-reviewed
Hiraga, Y., Sato, Y., Smith, R.L.
Fluid Phase Equilibria 420 36-43 2016
DOI：
10.1016/j.fluid.2015.10.042
ISSN：
0378-3812
eISSN：
1879-0224
-
Separation factors for [amim]Cl-CO2 biphasic systems from high pressure density and partition coefficient measurements
Peer-reviewed
Yuya Hiraga, Aya Kato, Yoshiyuki Sato, Taku M. Aida, Masaru Watanabe, Richard L. Smith
SEPARATION AND PURIFICATION TECHNOLOGY 155 139-148 2015/11
DOI：
10.1016/j.seppur.2015.03.008
ISSN：
1383-5866
eISSN：
1873-3794
-
Viscosity and density of poly(ethylene glycol) and its solution with carbon dioxide at 353.2 K and 373.2 K at pressures up to 15 MPa
Peer-reviewed
Masayuki Iguchi, Yuya Hiraga, Kazuhiro Kasuya, Taku Michael Aida, Masaru Watanabe, Yoshiyuki Sato, Richard Lee Smith
JOURNAL OF SUPERCRITICAL FLUIDS 97 63-73 2015/02
DOI：
10.1016/j.supflu.2014.10.013
ISSN：
0896-8446
eISSN：
1872-8162
-
Development of a simple method for predicting CO2 enhancement of H2 gas solubility in ionic liquids
Peer-reviewed
Hiraga, Y., Sato, Y., Smith, R.L.
Journal of Supercritical Fluids 96 162-170 2015
DOI：
10.1016/j.supflu.2014.09.010
ISSN：
0896-8446
eISSN：
1872-8162
-
Densities at pressures up to 200 MPa and atmospheric pressure viscosities of ionic liquids 1-ethyl-3-methylimidazolium methylphosphate, 1-ethyl-3-methylimidazolium diethylphosphate, 1-butyl-3-methylimidazolium acetate, and 1-butyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide
Peer-reviewed
Hiraga, Y., Kato, A., Sato, Y., Smith, R.L.
Journal of Chemical and Engineering Data 60 (3) 876-885 2015
DOI：
10.1021/je5009679
ISSN：
0021-9568
-
Measurement of high-pressure densities and atmospheric viscosities of ionic liquids: 1-hexyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide and 1-Hexyl-3-methylimidazolium chloride
Peer-reviewed
Iguchi, M., Hiraga, Y., Sato, Y., Aida, T.M., Watanabe, M., Smith Jr., R.L.
Journal of Chemical and Engineering Data 59 (3) 709-717 2014
DOI：
10.1021/je4007844
ISSN：
0021-9568
-
Partition coefficients of furan derivative compounds in 1-n-butyl-3-methylimidazolium chloride ([bmim][Cl])-supercritical CO<inf>2</inf> biphasic systems and their correlation and prediction with the LSER-δ model
Peer-reviewed
Hiraga, Y., Hayasaka, A., Sato, Y., Watanabe, M., Smith Jr., R.L.
Journal of Supercritical Fluids 79 32-40 2013
DOI：
10.1016/j.supflu.2012.11.010
ISSN：
0896-8446
-
Infinite dilution partition coefficients of benzene derivative compounds in supercritical carbon dioxide + ionic liquid systems: 1-butyl-3- methylimidazolium chloride [bmim][Cl], 1-butyl-3-methylimidazolium acetate [bmim][Ac] and 1-butyl-3-methylimidazolium octylsulfate [bmim][OcSO4]
Peer-reviewed
Hiraga, Y., Endo, W., Machida, H., Sato, Y., Aida, T.M., Watanabe, M., Smith Jr., R.L.
Journal of Supercritical Fluids 66 49-58 2012
DOI：
10.1016/j.supflu.2011.08.003
ISSN：
0896-8446
-
イオン液体-超臨界CO2間におけるベンゼン誘導体の無限希釈分配係数の測定および相関
平賀 佑也, 佐藤 善之, 相田 卓, 渡邉 賢, Smith Jr. R. L.
化学工学会 研究発表講演要旨集 2010 1109-1109 2010
Publisher:
公益社団法人 化学工学会
DOI：
10.11491/scej.2010f.0.1109.0
https://orcid.org/0000-0003-1129-2363