CI.—A study of the Landsberger-Sakurai boiling-point method of determining molecular weights

1910 ◽  
Vol 97 (0) ◽  
pp. 1184-1193 ◽  
Author(s):  
William Ernest Stephen Turner
Keyword(s):  
Boiling Point ◽  
Point Method ◽  
Molecular Weights

Sol-Gel Derived Ceramic Bubbles

1994 ◽  
Vol 372 ◽  
Author(s):  
Kyung H. Moh
Keyword(s):  
Metal Oxide ◽  
Wall Thickness ◽  
Glass Ceramic ◽  
Boiling Point ◽  
Sol Gel ◽  
Point Method ◽  
Oxide Component ◽  
Thermal Gelation ◽  
Solid Liquid ◽  
Sol Precursor

AbstractSol-gel derived ceramic bubbles include shaped and fired, porous or impermeable nonvitreous ceramic microcapsules of metal oxide and non-oxide, are made by non-melt process involving the equilibrium boiling point method with controlled thermal gelation. Discrete, free-flowing, ceramic microbubbles consist of a non-oxide component and/or an oxide component having diameters in the range of I to 300 micrometers and each having a wall thickness of less than 10 percent of the diameter of the bubble. In this process, a sol precursor and a bloating agent, when added to a bubble promoting medium under proper conditions, provide green gelled microbubbles which after firing are strong, well formed, ceramic microbubbles. The microbubbles are non-vitreous, sol-gel derived, fine microstructured, uniform, hollow, smooth, and are essentially all oxide or non-oxide or combinations of both. The microbubbles can be used as fillers for metal, glass, ceramic, and polymer or filled with a selected solid, liquid or gas for purpose of storing, transporting, or facilitating the use of the same.

EBULLIOMETRY AND THE DETERMINATION OF THE MOLECULAR WEIGHTS OF POLYMERS: PART II. BACKGROUND NOISE IN THE SMALL EBULLIOMETER

1959 ◽  
Vol 37 (9) ◽  
pp. 1517-1526 ◽  
Author(s):  
W. R. Blackmore
Keyword(s):  
Boiling Point ◽  
Background Noise ◽  
Polymer Solutions ◽  
Liquid Surface ◽  
Pressure Fluctuations ◽  
High Polymer ◽  
Molecular Weights ◽  
Usual Form ◽  
Lower Background

It is shown that the usual form of ebulliometer is subject to at least three sources of noise. Those discussed here are (1) pressure fluctuations over the boiling liquid surface, (2) the Cottrell pump, and (3) the foam which appears on many polymer solutions when maintained at the boiling point. Background noise in this, and other ebulliometers commonly employed, may be large compared to the size of the signals expected for dilute high polymer solutions. Consequently further progress in ebulliometry is dependent on the development of a new ebulliometer with a much lower background noise.

scholarly journals Measured Solid State and Sub-Cooled Liquid Vapour Pressures of Benzaldehydes Using Knudsen Effusion Mass Spectrometry

Atmosphere ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 397
Author(s):  
Petroc Shelley ◽  
Thomas J. Bannan ◽  
Stephen D. Worrall ◽  
M. Rami Alfarra ◽  
Carl J. Percival ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Solid State ◽  
Vapour Pressure ◽  
Boiling Point ◽  
Point Method ◽  
Scanning Calorimetry ◽  
Knudsen Effusion ◽  
Pressure Method ◽  
Liquid Saturation ◽  
Knudsen Effusion Mass Spectrometry

Benzaldehydes are components of atmospheric aerosol that are poorly represented in current vapour pressure predictive techniques. In this study the solid state (PSsat) and sub-cooled liquid saturation vapour pressures (PLsat) were measured over a range of temperatures (298–328 K) for a chemically diverse group of benzaldehydes. The selected benzaldehydes allowed for the effects of varied geometric isomers and functionalities on saturation vapour pressure (Psat) to be probed. PSsat was measured using Knudsen effusion mass spectrometry (KEMS) and PLsat was obtained via a sub-cooled correction utilising experimental enthalpy of fusion and melting point values measured using differential scanning calorimetry (DSC). The strength of the hydrogen bond (H-bond) was the most important factor for determining PLsat when a H-bond was present and the polarisability of the compound was the most important factor when a H-bond was not present. Typically compounds capable of hydrogen bonding had PLsat 1 to 2 orders of magnitude lower than those that could not H-bond. The PLsat were compared to estimated values using three different predictive techniques (Nannoolal et al. vapour pressure method, Myrdal and Yalkowsky method, and SIMPOL). The Nannoolal et al. vapour pressure method and the Myrdal and Yalkowsky method require the use of a boiling point method to predict Psat. For the compounds in this study the Nannoolal et al. boiling point method showed the best performance. All three predictive techniques showed less than an order of magnitude error in PLsat on average, however more significant errors were within these methods. Such errors will have important implications for studies trying to ascertain the role of these compounds on aerosol growth and human health impacts. SIMPOL predicted PLsat the closest to the experimentally determined values.

XIII.—A Method for Determining the Molecular Weights of Dissolved Substances by Measurement of Lowering of Vapour Pressure

1912 ◽  
Vol 31 ◽  
pp. 259-261
Author(s):  
Alan W. C. Menzies
Keyword(s):  
Vapour Pressure ◽  
Boiling Point ◽  
Molecular Weights

Although various methods have from time to time been described for determining the molecular weights of dissolved substances by measurement, not of boiling-point elevation, but of the reduction of vapour pressure of a solvent due to the presence of a dissolved substance, none of these methods has come into general use. The method here proposed, operating on this principle, offers the possibility of simply determining the molecular weights of non-volatile solutes in any of the ordinary solvents with an accuracy at least equal to that of the ebullioscopic methods, and in an apparatus at least as easily manageable.

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