Cyclohexane as a cryoscopic solvent

Steffel, Margaret J.

doi:10.1021/ed058pa133

Cited by 2 publications

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“…Colligative properties of solutions, such as osmotic pressure, boiling point elevation, and freezing point depression, are properties that only depend on the number of dissolved solutes but not their identity. Common, longstanding chemistry laboratory curriculum experiments involve the determination of the molecular weight of nondissociable organic solutes by means of the boiling point elevation or freezing point depression, − recognizing that absolute change in phase transition temperature relative to the pure solvent, Δ T , is proportional to the solute molality, m , according to eq with K being either the molal freezing point depression or boiling point elevation constant. An underlying assumption in eq is that the solute does not aggregate, which is the case for many organic solutes in organic solvents. Conversely, solute aggregation is in principle detectable by a lesser Δ T than expected from solution molality.…”

Section: Introductionmentioning

confidence: 99%

Combining Freezing Point Depression and Self-Diffusion Data for Characterizing Aggregation

Hoffmann

Bothe²,

Gutmann³

et al. 2018

J. Phys. Chem. B

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The colligative property freezing point depression is evaluated as a means for estimating the extent of aggregation for solutions of poly(ethylene oxide) alcohol (CE) nonionic surfactant in cyclohexane. Combined with additional measurements of self-diffusion coefficients, it is shown that both unaggregated CE as well as reverse micelles are significantly present for the entire range of measured CE concentration (0.048-2.35 mol kg). A change in speciation near 0.2 mol kg is indicated by the results from both freezing point depression and self-diffusion coefficient measurements. It is shown that average reverse micelle radii and aggregation numbers obtained from the ratio of solvent and CE self-diffusion coefficients are consistent with prior reported results. However, unreasonably small radii for the reverse micelles as well as for the cyclohexane were obtained from analysis of the results by the Stokes-Einstein equation using additional measured solution viscosities. The concentration of reverse micelles and unaggregated CE was calculated from the freezing point depression results using the aggregation numbers obtained from ratio of self-diffusion coefficients. These concentrations indicate that the reverse micelles become smaller in average size and increase in number with increasing temperature without an increase in unaggregated CE.

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Section: Introductionmentioning

confidence: 99%

Combining Freezing Point Depression and Self-Diffusion Data for Characterizing Aggregation

Hoffmann

Bothe²,

Gutmann³

et al. 2018

J. Phys. Chem. B

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“…This work deals with the preparation of cyclohexane (CH)‐based thin film coatings using PECVD process towards application in the above vapor sensing. The CH is mainly used for preparing low dielectric constant ( k ) thin films for electronic chips, 1, 2 as solvent in many chemical reactions, 3 as dispersant in polymer sensors, 4 as chemosensors based on CH moiety influence, 5 for preparing paint and acids, 6 and so forth. But applying polymerized CH as a gas‐sensing film was not reported.…”

Section: Introductionmentioning

confidence: 99%

Plasma‐polymerized cyclohexane coatings for ethanol and ammonia vapors sensing

Ananth

Seo

Boo

2020

Asia-Pacific J Chem Eng

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In this study, plasma-enhanced chemical vapor deposition of cyclohexane thin films was prepared for application towards ethanol and ammonia vapor sensing between the range 100 and 1,000 ppm. The deposited film exhibited stable, uniform coating and smooth surface morphology with minor surface roughness. The thickness of the coatings was 40-46 nm. The gas-sensing behavior against the experimental parameters such as coating thickness, operating temperature, and gas concentration was investigated. It was noted that increasing the coating thickness reduced the sensor's electrical conductivity. Increment in the operating temperature from 75 C to 100 C increased the sensor performance linearly. The ethanol and ammonia concentration effects were mainly influenced by the above two factors. The results demonstrated that the cyclohexane thin films can be used to fabricate low-cost gas sensors in addition to its conventional use as a low dielectric material.

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Cyclohexane as a cryoscopic solvent

Abstract: The author explores options for replacing benzene in the academic laboratory.

Cited by 2 publications

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Combining Freezing Point Depression and Self-Diffusion Data for Characterizing Aggregation

Combining Freezing Point Depression and Self-Diffusion Data for Characterizing Aggregation

Plasma‐polymerized cyclohexane coatings for ethanol and ammonia vapors sensing

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