Phase Transitions in Solid Methanol

Torrie, B. H.; Binbrek, O. S.; Strauss, M.; Swainson, I. P.

doi:10.1006/jssc.2002.9615

Cited by 71 publications

(72 citation statements)

References 9 publications

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“…Note that in the orientationally disordered phase k(T) is determined by localized states of different origin. The thermal conductivity of methanol was calculated using: Ì = 32.04 g/mol; r = 1015 kg/m 3 [13]; the mean sound velocity v = 1400 m/s was calculated using the data for the longitudinal sound velocity [33]; Q = 106 K was calculated from the v-value. Table 1 gives the fitting parameters obtained by comparing experimental results and calculated curves.…”

Section: Experiments and Discussionmentioning

confidence: 99%

“…At varying temperature and pressure, methanol displays more equilibrium phases than ethanol [4][5][6]13]. Polymorphism of the crystalline phases of methanol is governed by its H bonds which are stronger than the dispersive molecular interactions and by its simpler molecular structure in comparison to ethanol.…”

Section: Introductionmentioning

confidence: 99%

“…Upon the further decrease of temperature, a solid-solid transformation into the low-temperature orientationally-ordered state (a-phase) occurs at T a-b = = 157.4 K [13]. Their space groups are P2 1 2 1 2 1 for a-phase and Cmcm b-phase [13].…”

Section: Introductionmentioning

confidence: 99%

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Heat transfer in solid methyl alcohol

Korolyuk

Кривчиков

Sharapova

et al. 2009

Low Temperature Physics

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Thermal conductivity coefficient k(T) of two crystalline (orientationally-ordered and orientationally-disordered) phases of pure methanol (at temperatures from 2 K to T m , T m is the melting temperature), CH 3 OH + 6.6 % H 2 O glass from 2 K to T g , T g is the glass transition temperature and a supercooled liquid from T g to 120 K has been measured under equilibrium vapor pressure. The dependence k(T ) is described approximately as a sum of two contributions: k I (T) describing heat transport by acoustic phonons and k II (T) -by localized high-frequency excitations. The temperature dependences of the thermal conductivity of primary monoatomic alcohols CH 3 OH, C 2 H 5 OH, and C 3 H 7 OH in the glass state have been compared. Different mechanisms of phonon scattering in the crystalline phases and glass have been analyzed. The k II (T) has been calculated within the Cahill-Pohl model. There is an anomaly of the thermal conductivity of the glass state near T g (a smeared minimum in the k(T) -curve).

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Section: Experiments and Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Heat transfer in solid methyl alcohol

Korolyuk

Кривчиков

Sharapova

et al. 2009

Low Temperature Physics

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“…Consistent with similar data presented for pure methanol, 37 the OM atoms of neighbouring molecules are most likely found along the direction of the OM-H1M bond, when the central molecule acts as a hydrogen bond donor, as well as below the OM atom of the central molecule as it accepts hydrogen bonds from neighbouring molecules. 65 , pure crystalline benzene (magenta), 64 and liquid methanol (blue). 37 (b) OM-OM tij(r) separated into contributions from 1 st , 2 nd , 3 rd and 4 th closest neighbours using the ANGULA software.…”

Section: Local Structure Of the Benzene-methanol Azeotropementioning

confidence: 99%

Microstructures of negative and positive azeotropes

Shephard

Callear

Imberti

et al. 2016

Phys. Chem. Chem. Phys.

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The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. Azeotropes famously impose fundamental restrictions on distillation processes, yet their special thermodynamic properties make them highly desirable for a diverse range of industrial and technological applications. Using neutron diffraction, we investigate the structures of two prototypical azeotropes, the negative acetone-chloroform and the positive benzenemethanol azeotrope. C-H···O hydrogen bonding is the dominating interaction in the negative azeotrope but C-Cl···O halogen bonding contributes as well. Hydrogen-bonded chains of methanol molecules, which are on average longer than in pure methanol, are the defining structural feature of the positive azeotrope illustrating the fundamentally different local mixing in the two kinds of azeotropes. The emerging trend for both azeotropes is that the more volatile components experience the more pronounced structural changes in their local environments as the azeotropes form. The mixing of the acetonechloroform azeotrope is essentially random above 20 Å where the running Kirkwood-Buff integrals of our structural model converge closely to the ones expected from thermodynamic data. The benzene-methanol azeotrope on the other hand displays extended methanol-rich regions and consequently, the running Kirkwood-Buff integrals oscillate up to at least 60 Å. Our study provides first insights into the microstructures of azeotropes and a direct link with their thermodynamic properties. Ultimately, this will provide a route for creating tailored molecular environments in azeotropes to improve and fine-tune their performances.

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“…On cooling, methanol freezes at 175.37 K, giving the 'high temperature' β phase (Cmc2 1 ) which undergoes a first order phase transition to the lower temperature α phase (P2 1 2 1 2 1 ) 110 at 156-159 K. 45 There is debate as to whether there is a second, second-order phase transition between 156 and 159 K, but no structural information has been reported for this elusive phase. 46 Methanol also has a third structure in P ̅ , which is made evident not by temperature but by increasing the pressure on a single crystal. This was done in a DAC by increasing the pressure above 7 GPa to give a number of crystallites, then reducing the pressure until one seed crystal remained which was subsequently grown to fill the gasket hole at 4.0(1) GPa.…”

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confidence: 99%

Structure of organic solids at low temperature and high pressure

et al. 2014

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Publisher's copyright statement:Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-pro t purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. This tutorial review looks at structural and supramolecular chemistry of molecular solids under extreme 5 conditions, and introduces the instrumentation and facilities that enable single crystal diffraction studies on molecular crystals at both high pressure and low temperature. The equipment used for crystallography under extreme conditions is explored, particularly pressure cells such as the diamond anvil cell, and their mechanism of action, as well the as cryogenic apparatus which allows materials to be cooled to significantly low temperatures. The review also covers recent advances in the structural chemistry of 10 molecular solids under extreme conditions with an emphasis on the use of singe crystal crystallography in high pressure and low temperature environments to probe polymorphism and supramolecular interactions.

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Phase Transitions in Solid Methanol

Cited by 71 publications

References 9 publications

Heat transfer in solid methyl alcohol

Heat transfer in solid methyl alcohol

Microstructures of negative and positive azeotropes

Structure of organic solids at low temperature and high pressure

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