Guide to by-products formed in organic solvents under solvothermal conditions

Bondesgaard, Martin; Becker, Jacob; Jusseau, Xavier; Hellstern, Henrik L.; Mamakhel, Aref; Iversen, Bo B.

doi:10.1016/j.supflu.2016.02.012

Cited by 33 publications

(32 citation statements)

References 114 publications

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“…In addition, a significant amount of gases, in which hydrogen and carbon monoxide account for 40-50% of the total yield, is produced at high temperatures, under supercritical conditions in particular. 47 A favourable reductive environment is therefore created from the viewpoint of synthesis of metal nanomaterials. In addition, these alcohols contain hydroxyl groups, and some free hydroxyl ions might be present from the dissociation at increased temperatures which also display reduction capability.…”

Section: Reductive Supercritical Solventsmentioning

confidence: 99%

Chemistry in supercritical fluids for the synthesis of metal nanomaterials

Musumeci

Aymonier

2019

React. Chem. Eng.

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Section: Reductive Supercritical Solventsmentioning

confidence: 99%

Chemistry in supercritical fluids for the synthesis of metal nanomaterials

Musumeci

Aymonier

2019

React. Chem. Eng.

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“…From control experiments using individual pure alcohols at 400 • C for 60 min, Jo et al [42] found the self-decomposition of methanol, ethanol, and isopropanol to be only 0.1%, 3.2%, and 4.8%, respectively. In solvothermal liquefaction experiments with ethanol, Bondesgaard et al [43] found only a slight formation of by-products below the critical temperature of ethanol but observed a sharp increase in the number of by-products (71 species) at 450 • C and a total ethanol decomposition of 4.86%.…”

Section: Ethanolmentioning

confidence: 99%

“…Despite its reported hydrogen donor ability, the application of IPA as solvent or co-solvent in the HTL process is still rare. IPA is reported to be more stable than ethanol under liquefaction treatment because the ketone derived from dehydrogenation of isopropanol (acetone) is more resistant towards decomposition than is the aldehyde derived from ethanol (acetaldehyde) [43].…”

Section: Isopropyl Alcohol (Ipa)mentioning

confidence: 99%

Use of Co-Solvents in Hydrothermal Liquefaction (HTL) of Microalgae

et al. 2019

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This study reviewed and summarized the literature regarding the use of alcohols during hydrothermal liquefaction (HTL) of algal biomass feedstocks. The use of both pure alcohols and alcohol-water co-solvents were considered. Based upon this review, laboratory experiments were conducted to investigate the impacts of different alcohol co-solvents (ethanol, isopropanol, ethylene glycol, and glycerol) on the HTL treatment of a specific saltwater microalga (Tetraselmis sp.) at two temperatures: 300 °C and 350 °C. Based on their performance, two co-solvents, isopropanol and ethylene glycol, were selected to explore the effects of varying solvent concentrations and reaction temperatures on product yields and biocrude properties. The type and amount of added alcohol did not significantly affect the biocrude yield or composition. Biocrude yields were in the range of 30–35%, while a nearly constant yield of 21% insoluble products was observed, largely resulting from ash constituents within the algal feedstock. The benefits of using alcohol co-solvents (especially isopropanol) were the reduced viscosity of the biocrude products and reduced rates of viscosity increase with biocrude aging. These effects were attributed mainly to the physical properties of the co-solvent mixtures (solubility, polarity, density, etc.) rather than chemical processes. Under the reaction conditions used, there was no evidence that the co-solvents participated in biocrude production by means of hydrogen donation or other chemical processes. Recovery and recycling of the co-solvent present various challenges, depending upon the type and amount of the co-solvent that is used. For example, glycol solvents are recovered nearly completely within the aqueous product stream, whereas simple alcohols are partitioned between the biocrude and aqueous product streams. In commercial applications, the slight benefits provided by the use of co-solvents must be balanced by the challenges of co-solvent recovery and recycling.

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“…37,58 This likely hinges on the reported temperature-controlled reaction behavior of organic solvents at solvothermal condition. 35 Elemental The morphology of the particles has been studied by TEM in all samples. The micrographs are shown in Figure 6.…”

Section: Nanoparticle Sizesmentioning

confidence: 99%

Supercritical Flow Synthesis of Pt_1–xRu_xNanoparticles: Comparative Phase Diagram Study of Nanostructure versus Bulk

et al. 2017

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The thermodynamic stability of nanocrystals is different from bulk systems, and nanoscale phase diagrams are to a large degree unknown. Here we present a systematic investigation of the Pt1-xRux phase diagram through supercritical flow-synthesis of Pt1-xRux nanoparticles across the entire compositional range. The synthesis was done in stoichiometric steps of 0.1 using an ethanol-toluene mixture as solvent at 450°C and 200 bar. The products were characterized by high resolution synchrotron powder X-ray diffraction, transmission electron microscopy and elemental mapping of individual particles using energy-dispersive X-ray spectroscopy. The diffraction data revealed a single phase fcc alloy for x ≤ 0.2, while an additional hcp phase emerges as x approaches 1. This behavior deviates significantly from the bulk phase diagram where a biphasic region is only observed 2 for 0.62 < x < 0.8. Thus, compositional design of Pt-Ru alloys is more flexible on the nanoscale opening up significant possibilities for catalyst optimization. Rietveld refinements and microstructural line profile analysis show that the fcc unit cell dimensions follow Vegard's law within a good approximation. On the other hand, crystallite size, microstrain, phase content and hcp c/a ratio depend non-linearly on x but shows some correlation to the bulk phase diagram. Elemental mapping show the nanoparticles to be homogeneous, but in some cases fcc-hcp phase boundaries and modulations in the elemental distribution were observed. All samples below x < 0.3 exhibit a spherical morphology. At higher ruthenium content, x ≥ 0.3, another morphology emerges with elongated particles together with the dominating spherical mophology.The TEM average particle sizes ranging from 5.0(8) to 10.4(7) nm.

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Guide to by-products formed in organic solvents under solvothermal conditions

Cited by 33 publications

References 114 publications

Chemistry in supercritical fluids for the synthesis of metal nanomaterials

Chemistry in supercritical fluids for the synthesis of metal nanomaterials

Use of Co-Solvents in Hydrothermal Liquefaction (HTL) of Microalgae

Supercritical Flow Synthesis of Pt_1–xRu_xNanoparticles: Comparative Phase Diagram Study of Nanostructure versus Bulk

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Guide to by-products formed in organic solvents under solvothermal conditions

Cited by 33 publications

References 114 publications

Chemistry in supercritical fluids for the synthesis of metal nanomaterials

Chemistry in supercritical fluids for the synthesis of metal nanomaterials

Use of Co-Solvents in Hydrothermal Liquefaction (HTL) of Microalgae

Supercritical Flow Synthesis of Pt1–xRuxNanoparticles: Comparative Phase Diagram Study of Nanostructure versus Bulk

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Product

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Supercritical Flow Synthesis of Pt_1–xRu_xNanoparticles: Comparative Phase Diagram Study of Nanostructure versus Bulk