Calorimetric properties of benzoic acid from 0-degrees to 410-degrees-K

Furukawa, George T.; McCoskey, Robert E.; King, G. J.

doi:10.6028/jres.047.032

Cited by 134 publications

(41 citation statements)

References 6 publications

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“…The results are consistently high (0.1-0.3%) relative to the data of Furukawa et al (15). The discrepancy is probably sample-related since the work of ref.…”

Section: Performance Of the Systemmentioning

confidence: 42%

Calorimetric studies of the phase transition in iodoform

Boerio‐Goates¹,

Woodfield²

1988

Can. J. Chem.

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. 66, 645 (1988).The heat capacity of crystalline iodoform prepared by vacuum sublimination has been measured from 50 to 340 K and that of iodoform prepared by recrystallization from acetone measured from 120 to 300 K. Both samples exhibit a phase transition near 260 K. The heat capacity anomaly in the sublimed material shows several small maxima which appear with variable positions and heights depending upon the thermal pretreatment of the sample. The transition, which was undetected by previously-reported spectroscopic measurements, is ascribed to an incomplete ordering of the molecular dipole.JULIANA BOERIO-GOATES et BRIAN F. WOODFIELD. Can. J. Chem. 66, 645 (1988). On ti mesurt la capacitt calorifique de l'iodoforme cristallin prtpart par sublimation sous vide 21 des temperatures allant de 50 a 340 K et celle de l'iodoforme prtpart par recristallisation de I'acCtone de 120 ? i 300 K. Les deux Cchantillons presentent une transition de phase prts de 260 K. Dans l'tchantillon prCpart par sublimination, on note une anomalie dans IacapacitC calorifique qui se traduit par plusieurs petits maxima qui apparaissent 2 des positions variables et dont les hauteurs dtpendent du prt-traitement thermique qu'a subi I'tchantillon. C'est B arrangement incomplet du dip8le moltculaire qu'on attribue la transition qui n'avait pas ttC dCtectCe au cours des mesures spectroscopiques rkalisees anttrieurement.[Traduit par la revue] Introduction Halogenated methane derivatives are of interest to theorists and experimentalists probing molecular dynamics in the solid state. These compounds also exhibit an interesting range of crystallographic structures and polymorphic phase transitions at different temperatures. The haloforms, CHX3 with X = F, C1, Br, and I, have been widely studied by techniques like X-ray (1, 2) and neutron (3, 4) diffraction, Raman and ir spectroscopy (5-7) and dielectric measurements (8) which probe structuial details of the solid-state and characterize phase transitions. However, high-precision heat capacity measurements, frequently used to study phase transitions, have been published only for fluoroform (9); differential scanning calorimetric (DSC) measurements (8) near the solid-liquid and solid-solid phase transitions in bromoform have been made, but no quantitative data were published from this study.In this paper we report heat capacity measurements of iodoform in order to resolve a discrepancy regarding the existence of a phase transition in this compound. The disagreement arises between spectroscopic (5,7) studies which show no evidence for a phase transition as the temperature is lowered, and temperature-dependent photoconductivity measurements (10) which exhibit anomalous behavior below 270 K that has been attributed to the onset of a phase transition. The manner of sample preparation differed between two of the investigations: one spectroscopic study (5) used crystals grown from acetone solution while the photo-conductivity measurements (10) were performed on samples of CHI3 prepared by vacuum sublimatio...

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“…The results are consistently high (0.1-0.3%) relative to the data of Furukawa et al (15). The discrepancy is probably sample-related since the work of ref.…”

Section: Performance Of the Systemmentioning

confidence: 42%

Calorimetric studies of the phase transition in iodoform

Boerio‐Goates¹,

Woodfield²

1988

Can. J. Chem.

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“…The scattering in the heatcapacity results of X-454 copolymer does not seem to support this, however. The he.at-capaci~y m~as urements with more normal matenals [5,8] Except for the transition intervals, the tabulated (tables 4 and 7) enthalpy and entropy for the two copolymers were obtained, as previously shown, from the smoothed heat capacities. These thermal quantities are dependent upon the accuracy of the ~1eat capacity from which they ~vere evaluated.…”

Section: Relia Bility Of Resultsmentioning

confidence: 99%

“…After cooling the polymer to the desired temperature, the heat-capacity measurements were made at progressively higher temperatures, the final temperature of the first measurement being the initial temperature of the second measurement, and so forth up the temperature scale. As heat-capacity measurements with simpler substances [5,8] show that normal temperature equilibrium was established in 6 to 7 min after the heating period, any persistent temperature drift after the eighth minute was considered to arise from the thermal effects in the polymeric material.…”

Section: Apparatus and Methodsmentioning

confidence: 99%

“…Thus, no further attempt was made in other experiments to reach thermal equilibrium. The temperature m easurem ents were started at times (about 6 to 7 min after the end of heating ) u sually required for thermal equilibrium with simpler materials [5,8]. Experience with the X -454 copolymer and the other polymer s, recently investigate d at th e Bureau, shows that the waiting period for thermal equilibrium can b e extremely long.…”

Section: 2 Gl-658 122 0 F Copolymermentioning

confidence: 99%

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Thermal properties of some butadiene-styrene copolymers

Furukawa¹,

McCoskey²,

King³

1953

J. RES. NATL. BUR. STAN.

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The t he rm a l proper ties of 4 1 0 and 122 0 F butadiene-tyre ne copolym ers co n tainin g 8.58 perce nt of bound-sty rene were i n vestiga ted by m eans of an adia batic cal orimeter fr om 16 0 t o 330 0 K . The 4 1 0 F copolym er was found t o crystallize in t he temperat ure ran ge fr om 210 0 to 285 0 K . The 122 0 F co polym er did not exhibi t any crystallizatio n. The glasst ransfo:mat ion te mperat ures of t he 41 0 and 122 0 F co poly mers were 200 0 a nd 193 0 K , resp~ct lv e l y.The effects of heat tre~t me n t upon the heat capaci ty a nd t he glass-t ra nsforma tIOn te mperat ure have bee n studIed. The res ults of the hea t-capaci ty mea surem ents :vere used to co mpu te heat capacity, e nthalpy, and e nt ropy from 0 0 t o 33t}° K !"It 5-deg ltl te rv a ls.

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“…Statement of the authors of ref. [33]: Chapter 3.2, first paragraph: "Considering the precision and the various known sources of errors a probable error (footnote 4) of ± 0.2 percent is assigned to the heat-capacity values from 60°to 395°K". Footnote 4: "For these experiments a true probable error cannot be computed statistically.…”

Section: Copper (30-300 K)mentioning

confidence: 99%

Standards, calibration, and guidelines in microcalorimetry. Part 2. Calibration standards for differential scanning calorimetry* (IUPAC Technical Report)

Gatta

Richardson

Sarge

et al. 2006

Pure and Applied Chemistry

287

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Differential scanning calorimeters (DSCs) are widely used for temperature, heat capacity, and enthalpy measurements in the range from subambient to high temperatures. The present recommendations describe procedures and reference materials (RMs) for the calibration of DSCs. The recommendations focus on the calibration of the response of the instrument and on the estimation of the measurement uncertainty. The procedures for temperature, enthalpy, and heat-flow rate calibration are given in detail. Calibration on cooling has also been considered. Recommended RMs are listed, and the relevant properties of these materials are discussed.

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Calorimetric properties of benzoic acid from 0-degrees to 410-degrees-K

Cited by 134 publications

References 6 publications

Calorimetric studies of the phase transition in iodoform

Calorimetric studies of the phase transition in iodoform

Thermal properties of some butadiene-styrene copolymers

Standards, calibration, and guidelines in microcalorimetry. Part 2. Calibration standards for differential scanning calorimetry* (IUPAC Technical Report)

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