Thermodynamic properties of 1,6-anhydrohexopyranose crystals

Shafizadeh, Fred; McGinnis, Gary D.; Susott, Ronald A.; Philpot, Charles W.

doi:10.1016/s0008-6215(00)88001-5

Cited by 22 publications

(3 citation statements)

References 38 publications

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“…Thermodynamic studies of levoglucosan have been a popular endeavor during the past decade. − It is known that solid levoglucosan exists as two crystal phases. The low-temperature phase (crII) is the orientationally ordered crystal phase (space group, P2 1 2 1 2 1 ), while the high-temperature phase (crI) is the orientationally disordered crystal (or plastic crystal) phase. − The solid–solid phase transition occurs at T tr = 384.7 ± 0.2 K with a phase-transition enthalpy of Δ crII crI H m o = 24.3 ± 0.2 kJ·mol –1 . The plastic crystals (phase cr I) melt to a low-viscosity liquid at T fus = 455.3 ± 0.1 K with an enthalpy of fusion of Δ crI l H m o = 3.2 ± 0.1 kJ·mol –1 .…”

Section: Resultsmentioning

confidence: 99%

Commodity Chemicals and Fuels from Biomass: Thermodynamic Properties of Levoglucosan Derivatives

Андреева

Pimerzin

Туровцев

et al. 2021

Ind. Eng. Chem. Res.

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Cellulose-derived platform chemicals offer viable substitutes for most petroleumbased polymers and also enable the development of novel functional materials. In the focus of this work are thermophysical and thermochemical studies of dihydro-levoglucosenone (Cyrene) and levoglucosenone, which are considered as potential "green" replacements for industrial polar aprotic solvents. The densities, viscosities, absolute vapor pressures, and combustion energies of cyrene and levoglucosenone were measured in this work. The thermodynamic properties of levoglucosan derivatives are reliable for thermochemical calculations and used to calculate reaction enthalpies of valorization of the cellulose component of biomass. These enthalpies of reaction are useful in the further optimization and development of sustainable syntheses of commodity chemicals and fuels from biomass. The data provided in this work will aid researchers and engineers as the use of these new solvents grows.

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Section: Resultsmentioning

confidence: 99%

Commodity Chemicals and Fuels from Biomass: Thermodynamic Properties of Levoglucosan Derivatives

Андреева

Pimerzin

Туровцев

et al. 2021

Ind. Eng. Chem. Res.

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“…Interestingly, it was shown that besides ethanol, LG is so far the second-known compound capable of forming crystalline, plastic crystal (PC), liquid (LQ), orientational glass (OTG) and ordinary glass (OG) phases (Madejczyk et al, 2017;Srinivasan et al, 1996;Fayos et al, 1996). Besides many previous studies on the thermally induced transition of LG to PC at $383 K (Shafizadeh et al, 1970;Shafizadeh & Lai, 1972;Smith & Shafizadeh, 1971;Lienhard et al, 2012;Rocha et al, 2013;Tombari & Johari, 2015;Kamin ´ska et al, 2016), it is still of fundamental interest since, to the best of our knowledge, the LG structure in the orientationally disordered phase has not yet been solved. In this context, it is worth stressing that below 383 K LG exists as an ordered crystalline phase, first identified by Park et al (1971) through single-crystal X-ray diffraction as an orthorhombic system with space group P2 1 2 1 2 1 and four molecules per unit cell with unit-cell parameters a = 6.684 (2) A ˚, b = 13.266 (7) A ˚, c = 7.547 (2) A ˚.…”

Section: Introductionmentioning

confidence: 99%

“…It was concluded that LG molecules are linked into finite arrays formed by strong O-HÁ Á ÁO bonds supported by weaker C-HÁ Á ÁO interactions. Further heating of LG exhibits a second phase transition at around 460 K, corresponding to the melting point (Shafizadeh et al, 1970;Kamin ´ska et al, 2016). Our previous report showed that LG could also be obtained as OTG or OG phases from PC or LQ states, respectively, when undercooled below the glass transition temperature at $245 K with a very high cooling rate (Madejczyk et al, 2017).…”

Section: Introductionmentioning

confidence: 99%

Structure of 1,6-anhydro-β-D-glucopyranose in plastic crystal, orientational glass, liquid and ordinary glass forms: molecular modeling and X-ray diffraction studies

Jurkiewicz

Glajcar

Kamiński

et al. 2021

Acta Crystallogr Sect B

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The structures of the plastic crystal (PC), orientational glass (OTG), liquid (LQ) and ordinary glass (OG) phases of 1,6-anhydro-β-D-glucopyranose (levoglucosan) have been investigated using X-ray diffraction and molecular modeling. The experimental diffraction data in the forms of static structure factors and pair distribution functions are analyzed in reciprocal and real spaces and compared with results of model-based simulations. A new approach to modeling the structure of the disordered phases, taking into account the intermolecular scattering contribution in the form of sharp Bragg peaks, the slowly varying intensity associated with intramolecular correlations and the diffusive component resulting from structural disorder, is applied. In the case of the LQ and OG samples, reverse Monte Carlo simulations are also used. The PC and OTG phases show long-range ordering of the hexagonal close-packed (hcp)-type structure up to 120 Å with random orientation of the molecules. Assuming a rigid molecular skeleton, isotropic free rotations of the molecules about their geometrical center in full and limited angular ranges are generated in theoretical models of the structure. It is demonstrated that the adoption of free rotations of the molecules leads to the best fits to experimental data for each studied phase of levoglucosan. The diffraction patterns of the LQ and OG samples show a relatively sharp first peak originating from quasi-Bragg planes of the densely packed face-centered cubic (fcc) type molecular arrangement. Moreover, the slowly varied intensity component of LQ and OG is practically the same as that of PC and OTG, suggesting that the intramolecular structure of these four phases does not change. Interestingly, structural correlations for the disordered LQ and OG states extend surprisingly far, up to about 50 Å. In addition, for all levoglucosan phases investigated, the paracrystalline disorder imposed on the generated models resulted in better compliance with the experimental data.

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Thermal behavior of carbohydrates

Shafizadeh¹

1971

J. polym. sci., C Polym. symp.

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Thermal analysis of a hardwood reflected the pyrolysis of its main components including xylan and cellulose. Thermal properties of these components were investigated with model compounds consisting of α‐D‐xylose, substituted phenyl β‐D‐xylopyranosides, β‐Dglucopyranosides and α‐D‐arabino‐hexopyranosides and 1,6‐anhydro‐β‐D‐glucopyranose. At the lower temperatures these molecules displayed anomerization, loss of water and phase change, which were studied with a variety of physical methods. Calorimeteric and wide line NMR measurements showed that 1,6‐anhydro‐β‐D‐glucopyranose and related anhydro sugars undergo plastic crystalline transition, involving reorientation of the molecules about their centers of gravity and self‐diffusion before melting. At more elevated temperatures the above compounds showed cleavage of the glycosidic group, polymerization of the sugar moiety, decomposition and evaporation of the pyrolysis products. This involved some heterolytic reactions, which could be catalyzed by acid or alkaline materials. Kinetics of the pyrolysis process, including the rates and energies of activation were determined by thermal analysis and ESR spectroscopy. These data indicated that cleavage of the glycosidic bond is directly influenced by variation of its electron density and constitutes the rate determining step in pyrolysis of the carbohydrate compounds.

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Thermodynamic properties of 1,6-anhydrohexopyranose crystals

Cited by 22 publications

References 38 publications

Commodity Chemicals and Fuels from Biomass: Thermodynamic Properties of Levoglucosan Derivatives

Commodity Chemicals and Fuels from Biomass: Thermodynamic Properties of Levoglucosan Derivatives

Structure of 1,6-anhydro-β-D-glucopyranose in plastic crystal, orientational glass, liquid and ordinary glass forms: molecular modeling and X-ray diffraction studies

Thermal behavior of carbohydrates

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