Electron in cold alcohols: a pulse radiolysis study in ethanol

1977 ◽  
Vol 55 (11) ◽  
pp. 2003-2008 ◽  
Author(s):  
L. Gilles ◽  
M. R. Bono ◽  
M. Schmidt
Keyword(s):  
Pulse Radiolysis ◽  
Freezing Point ◽  
Transient Spectra

The pulse radiolysis of cold ethanol near its freezing point shows 'partly solvated' states of the electron with transient spectra whose maxima vary with time. It is shown that the determination of the solvation times of the electron can depend strongly on the wavelength considered; thus an explanation could be given for the different values obtained by Chase and Hunt at λ = 1300 and λ = 1050 nm.

Primary mechanisms in the radiolysis of amines: pulse and γ-radiolysis of neutral and acidic ethylamine, n-propylamine and ethylenediamine

1979 ◽  
Vol 57 (15) ◽  
pp. 2013-2021 ◽  
Author(s):  
J. A. Delaire ◽  
J. R. Bazouin
Keyword(s):  
Allyl Alcohol ◽  
Molecular Hydrogen ◽  
Pulse Radiolysis ◽  
Solvated Electron ◽  
Infrared Band ◽  
Solvated Electrons ◽  
Upper Limits ◽  
Transient Spectra ◽  
Alkyl Ammonium

The transient spectra in pure ethylamine (EA), n-propylamine (nPA), and ethylenediamine (EDA) show, besides the visible and infrared band associated with the solvated electron, e−s, a small ultraviolet band attributed to oxidizing radicals. Upper limits for the recombination rate constants k of e−s with the acidic cation are 1.5 × 1012 L mol−1 and 3.5 × 1012 L mol−1s−1 in EA and nPA respectively, and k = 2 × 1010 L mol−1 s−1 in EDA. The yield of e−s at 3 ns (G(e−s)3ns = 1.5, 1.2, and 3.1 molecules/100 eV in EA, nPA, and EDA respectively) has been deduced by biphenyl scavenging. The yield of molecular hydrogen after γ-radiolysis G0(H2) = 5.7 and 3.6 in pure nPA and EDA respectively. The effect of solutes, such as biphenyl, alkyl-ammonium chloride, and allyl alcohol, on G(H2) is interpreted in terms of scavenging of e−s and/or H atoms. From the pulse-radiolysis determination of G(e−s), we deduce [Formula: see text] in nPA.Finally, the decay of solvated electrons seems to occur only via recombination with the cation in EA and nPA, but in EDA there is a competition between this reaction and reaction with oxidizing radicals.

Cryoscopy of Milk: Effect of Variations in the Method

1966 ◽  
Vol 49 (3) ◽  
pp. 511-515 ◽  
Author(s):  
R W Henningson
Keyword(s):  
Statistical Analysis ◽  
Sample Size ◽  
Freezing Point ◽  
Collaborative Study ◽  
Sample Temperature ◽  
Milk Samples ◽  
Two Samples ◽  
Temperature Rate

Abstract Bath level, sample temperature, rate of stirring, degree of supercooling, sample size, sample isolation, and refreezing of the sample were the variables in the thermistor cryoscopic method for the determination of the freezing point value of milk chosen for study. Freezing point values were determined for two samples of milk and two secondary salt standards utilizing eight combinations of the seven variables in two test patterns. The freezing point value of the salt standards ranged from –0.413 to –0.433°C and from –0.431 to –0.642°C. The freezing point values of the milk samples ranged from –0.502 to –0.544°C and from –0.518 to –0.550°C. Statistical analysis of the data showed that sample isolation was a poor procedure and that other variables produced changes in the freezing point value ranging from 0.001 to 0.011°C. It is recommended that specific directions be instituted for the thermistor cryoscopic method, 15.040–15.041, and that the method be subjected to a collaborative study.

In situ freezing point determination of cryolite baths utilising resistometer measurements

2014 ◽  
Vol 18 (12) ◽  
pp. 3339-3344 ◽  
Author(s):  
Graeme A. Snook ◽  
Katherine McGregor ◽  
Andrew J. Urban
Keyword(s):  
Freezing Point ◽  
Point Determination

Determination of the Freezing Point of Milk by Thermistor Cryoscopy

1967 ◽  
Vol 50 (3) ◽  
pp. 533-537
Author(s):  
R W Henningson
Keyword(s):  
Freezing Point ◽  
Official Method ◽  
Milk Samples ◽  
Present Official Method ◽  
Proper Condition

Abstract Specific directions for the thermistor cryoscopic method, including uniformity in cooling, degree of supercooling, seeding, and reading procedures, are proposed for the present official method. It is emphasized that the instrument must be in the proper condition for use, must be properly calibrated, and must be properly utilized by the analyst. Each analyst should individually calibrate with standards by the same uniform procedure for standards and milk samples. The precautions necessary in the determination are part of the method and must be observed if the same sample is to yield the same freezing point value for different analysts, in different laboratories, at different times

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