Calorimetric Measurements at Low Temperatures in Toluene Glass and Crystal

Alvarez-Ney, C.; Labarga, Juan Manuel Martínez; Moratalla, Manuel; Castilla, J. M.; Ramos, M. A.

doi:10.1007/s10909-017-1760-8

Cited by 9 publications

(16 citation statements)

References 33 publications

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“…As discussed in our previous paper [34], earlier data of the specific heat of toluene are available for the crystal above 11 K [38] and for the glass above 5.6 K [39], using adiabatic calorimetry. Since toluene is a bad glass former and crystallizes readily, Yamamuro et al [39] doped toluene with 10 mol% benzene, then correcting the effects of doping by assuming the additivity of the heat capacities of toluene and benzene.…”

Section: Resultsmentioning

confidence: 99%

“…2, we show our new measurements of the specific heat of toluene doped with 2 mol% ethanol, for the crystal state and for two differently prepared glasses, using the abovementioned quasiadiabatic continuous method. After measuring the C p curve of the crystal up to above its melting temperature T m = 176 K (i.e., (2±1) K below that of pure toluene [34,38]), the liquid was quenched at about −43 K/min to bypass crystallization (fast glass). After measuring its C p (T) both at low and intermediate temperatures until slightly above the glass-transition temperature T g = 117 K, this supercooled liquid was frozen-in at a cooling rate of −0.4 K/min aiming to seek any possible difference between the properties of this slow glass and the former fast glass.…”

Section: Resultsmentioning

confidence: 99%

“…In this paper, we present new measurements of the specific heat of toluene, both in its crystal and glass states, improving and extending earlier ones [34]. In the temperature range roughly between 1.8 and 22 K, the standard thermal relaxation method was employed.…”

Section: Toluenementioning

confidence: 87%

“…0.02% H 2 O) also without further purification. In such a way, the specific heat curves for both glass and crystal states of the very same sample of toluene were measured and directly compared, in contrast to our previous measurements [34]. The small, additive known contribution of ethanol specific heat [35] to the measured heat capacity at low temperatures was correspondingly subtracted for glass and crystal.…”

Section: Materials and Experimental Techniquesmentioning

confidence: 99%

“…At temperatures below 25 K, the well-known thermal relaxation method was employed, whereas at higher temperatures a quasiadiabatic continuous method was used [34,36,37]. Much more information about the cryogenic system employed, electronic control, thermal sensors and heating elements can be found in Ref.…”

Section: Materials and Experimental Techniquesmentioning

confidence: 99%

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Residual entropy in the zero-temperature limit of toluene glass

Moratalla

Bejarano

Castilla

et al. 2019

Low Temperature Physics

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The specific heat C p of toluene, doped with 2 mol% ethanol to avoid rapid crystallization, has been measured in both glass and crystal states, and with special accuracy at low temperatures in the range 1.8−20 K using the thermal relaxation method. By making use of the complementary C p curves measured in the reference crystal state, we have been able to obtain the entropy curve of the glass and eventually the residual entropy of toluene glass in the zero-temperature limit, that is found to be 5.1 J/(K⋅mol). This value is clearly lower than others previously reported in the literature, which lack the knowledge of the particular specific-heat behavior of glasses at low temperatures and hence overestimated the glass residual entropy at zero temperature. In addition, we have studied in detail such low-temperature "glassy anomalies" in the case of toluene, extending and improving previous measurements. The surprising depletion previously reported of tunneling two-level systems in toluene glass has been confirmed, though this fact coexists with the presence of a broad peak typical of glasses (the socalled boson peak) in C p /T 3 at 4.5 K. For the toluene crystal, the expected cubic Debye behavior has been found at lower temperatures.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Toluenementioning

confidence: 87%

Section: Materials and Experimental Techniquesmentioning

confidence: 99%

Section: Materials and Experimental Techniquesmentioning

confidence: 99%

See 3 more Smart Citations

Residual entropy in the zero-temperature limit of toluene glass

Moratalla

Bejarano

Castilla

et al. 2019

Low Temperature Physics

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The State of the Art: Lightweight Cryocoolers Working in the Liquid-Helium Temperature Range

Yang

Gao

et al. 2022

J Low Temp Phys

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Does a Binary Phase Diagram Exist for a Solvent Containing a Single Solute Molecule? Case of a Neutral Solute Molecule in Ethanol

et al. 2019

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Binary phase (BP) diagrams have been a cornerstone in both the industrial and the academic research. Traditionally, the twocomponent BP diagrams always consider a finite amount of solute in a finite solvent host. Here, we consider a special situation: a single solute molecule in a structurally different solvent host and pose the question "Can the traditional BP diagram account for the behavior of a single solute in a finite solvent host?" To date, this aspect remains unexplored because of both practical difficulties in probing such dilute solutions and conceptual difficulties in formulating a BP diagram for such a single solute molecule case. In this work, we have overcome the experimental barrier and produced such a system in ethanolic solutions of a neutral solute molecule by exploiting the ethanol's property of crystallization from a translationally rigid plastic crystalline state. We studied the freezing behavior of dilute solutions of nitroxyl spin probes, 2,2,6,6-tetramethylpiperidin-1-oxyl (TEMPO), 4-hydroxy-TEMPO, 4-oxo-TEMPO, and 4-amino-TEMPO, in ethanol by electron paramagnetic resonance (EPR) spectroscopy. Computer simulations based on Stochastic Liouville theory were used to analyze the EPR spectra. The EPR results reveal that liquid domains (LDs) containing a single solute molecule are formed in ethanol ice and are subjected to strong confinement because of its own frozen solvent phase. No evidence of crystallization of these LDs is observed at any temperature. The observed behavior cannot be rationalized by the bulk BP diagram but could be understood by a self-confined BP diagram, where the freezing point curve is not bounded at lower temperatures. Interestingly, the size of the LD was estimated to be 2.0 nm, which is similar to the lower limit for crystallizing water.

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Calorimetric Measurements at Low Temperatures in Toluene Glass and Crystal

Cited by 9 publications

References 33 publications

Residual entropy in the zero-temperature limit of toluene glass

Residual entropy in the zero-temperature limit of toluene glass

The State of the Art: Lightweight Cryocoolers Working in the Liquid-Helium Temperature Range

Does a Binary Phase Diagram Exist for a Solvent Containing a Single Solute Molecule? Case of a Neutral Solute Molecule in Ethanol

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