scholarly journals FREEZING POINT DATA FOR UNH-H$sub 2$O-HNO$sub 3$ SYSTEMS

1947 ◽  
Author(s):  
M Harmon
Keyword(s):  
Freezing Point ◽  
Point Data

PRODUCTION AND PROPERTIES OF 2,3-BUTANEDIOL: XII. ANTIFREEZE PROPERTIES OF TERNARY AQUEOUS SOLUTIONS CONTAINING LEVO-2,3-BUTANEDIOL AS A MAJOR COMPONENT

1946 ◽  
Vol 24f (5) ◽  
pp. 287-299 ◽  
Author(s):  
K. A. Clendenning ◽  
D. E. Wright
Keyword(s):  
Ethylene Glycol ◽  
Aqueous Solutions ◽  
Boiling Point ◽  
Freezing Point ◽  
Ternary Systems ◽  
Freezing Points ◽  
Point Depressant ◽  
Point Data ◽  
Considerable Range

Freezing point, viscosity, and boiling point data are presented for aqueous solutions of levo-2,3-butanediol containing methanol, ethanol, ethylene glycol, and tetrahydrofurfuryl alcohol as third components. All four ternary systems show freezing points of −50 °C. and lower over a considerable range of compositions. Among the compounds tested as third components, methanol was most effective as a thinning agent and accessory freezing point depressant. The data indicate that 20% methanol–40% butanediol–40% water is suitable for use at temperatures as low as −50 °C.

scholarly journals The accurate determination of the freezing-points of alloys, and a study of valency effects in certain alloys of silver

1937 ◽  
Vol 160 (901) ◽  
pp. 282-303 ◽  
Keyword(s):  
Freezing Point ◽  
Equilibrium Diagram ◽  
Accurate Determination ◽  
Freezing Points ◽  
Experimental Errors ◽  
Series Of Experiments ◽  
Point Data ◽  
Many Sources ◽  
Straight Lines

In the alloys of silver with the four elements immediately following it in the Periodic Table, the silver rich alloys give rise to primary substitutional solid solutions for which the phase boundaries in the equilibrium diagram show well-defined valency effects. When the diagrams are plotted in atomic percentages, the liquidus and solidus curves fall more steeply with increasing valency of the solute, whilst the extent of the solid solution becomes less. It was shown (Hume-Rothery, Mabbott and Channel-Evans 1934) that, to a first approximation, the liquidus curves followed a simple valency rule, such that alloys of identical equivalent composition had identical freezing-points, and, hence, in dilute solutions where the liquidus curves were straight lines, the atomic depression of freezing-point was proportional to the valency of the solute. The experimental errors of 1 or 2°C. in the freezing-point data prevented an exact proof of a whole number law, and the present paper describes more accurate determinations of the freezing-points of these alloys. The first part of the experimental work was carried out by one of the authors (W. H. -R.) working alone, and the later work by the two authors together. It is convenient to refer to the two series of experiments as the early work and the later work respectively. In order to increase the accuracy of the liquidus determinations it has been necessary to examine many sources of error, and this work is described in 2; 3 contains the experimental results, which are discussed in 4.

FREEZING POINT DATA FOR A PORTION OF THE TERNARY SYSTEM: ACETAMIDE—PALMITIC ACID—STEARIC ACID

1960 ◽  
Vol 64 (11) ◽  
pp. 1613-1616
Author(s):  
Robert R. Mod ◽  
Frank C. Magne ◽  
Evald L. Skau
Keyword(s):  
Ternary System ◽  
Stearic Acid ◽  
Palmitic Acid ◽  
Freezing Point ◽  
Point Data

Characterization of Block and Random Ethylene Propylene Copolymers by Differential Thermal Analysis

1966 ◽  
Vol 39 (5) ◽  
pp. 1513-1519
Author(s):  
Edward M. Barrall ◽  
Roger S. Porter ◽  
Julian F. Johnson
Keyword(s):  
Block Copolymers ◽  
Freezing Point ◽  
Random Copolymer ◽  
High Heat ◽  
Peak Height ◽  
Chain Structure ◽  
Heat Of Fusion ◽  
Ethylene Content ◽  
Point Data ◽  
Physical Mixtures

Abstract DTA furnishes a reliable method for the analysis of physical mixtures and for multisegment and bisegment block copolymers of ethylene and propylene in cases where chain randomness is minor. If a secondary method of analysis which is independent of crystallinity is possible, e.g., use of C14-tagged samples, the DTA method can aid in elucidating the chain structure, including degree of copolymer randomness. Block copolymers and physical mixtures have been found to have thermograms with endothermal minima at approximately 138 and 163° C. The ratio of heights of the two minima has been found to be a function of the ethylene and propylene content for mixtures of homopolymers and for block copolymers without randomnness. Cooling thermograms of block copolymers have been demonstrated to have two exotherms in all cases where the block ethylene content exceeded 10 per cent; the propylene limit was not fixed. Mixed homopolymers do not exhibit two freezing exotherms. The total heat of fusion of the polymer has been found to be a usable measure of chain randomness and block nature. Conditions for observation of single and multiple transitions have been extended. The following conclusions can be drawn from Table I. Multisegment block copolymers are characterized by heats of fusion almost equal to or lower than corresponding physical mixtures. Bisegment block copolymers have heats of fusion equivalent to physical mixtures within experimental error. Cooling curves definitely indicate that samples 3–6 and 3–13 are block copolymers according to Ke's criterion of double exotherms. Sample 3–3 may be inferred to have a large amount of randomness between blocks from its low heat of fusion, which is comparable to that of polymers with known randomness. Samples 3–35 and 3–40 are both block copolymers by the double freezing point technique. The block copolymer identification and the high heat of fusion (almost as large as a comparable physical mixture) indicate long block length and only a few blocks. Very little randomness is present (compare data of Figure 2). Low heats of fusion consistent with short block segments in sequential arrangement are noted for samples 3–30 and 3–31. No confirmation of the block nature can be obtained from freezing point data due to low ethylene content. The displacement from curve in Figure 2 indicates noncrystalline segments in the chain. Multisegment block copolymers are identified from heat of fusion data and freezing point thermograms; note samples 3–32, 3–33, and 3–34. The location of the peak height ratios in Figure 2 indicates the presence of random copolymer with some crystallinity between blocks in all cases.

Freezing Points of Raw and Pasteurized Milks

1976 ◽  
Vol 39 (7) ◽  
pp. 462-463 ◽  
Author(s):  
G. H. WATROUS ◽  
S. E. BARNARD ◽  
W. W. COLEMAN
Keyword(s):  
Freezing Point ◽  
Cow Milk ◽  
Freezing Points ◽  
Added Water ◽  
Point Data

Over 2,000 samples of cow milk and 243 samples of processed milk were analyzed for freezing point. Data suggest the need for continuing surveillance of both raw and pasteurized milks. During the course of the study, the incidence of freezing points in processed milks suggestive of added water dropped markedly. It is suggested this may have been due to information gained during the study and consequent response.

Thermodynamics of micellar systems: activity and entropy of sodium decanoate and n-alkylamine hydrobromides in water

1981 ◽  
Vol 59 (13) ◽  
pp. 1865-1871 ◽  
Author(s):  
Rosario De Lisi ◽  
Gérald Perron ◽  
Jean Paquette ◽  
Jacques E. Desnoyers
Keyword(s):  
Heat Capacity ◽  
Aqueous Solutions ◽  
Homologous Series ◽  
Freezing Point ◽  
Activity Data ◽  
Micellar Systems ◽  
Point Data ◽  
Sodium Decanoate ◽  
Capacity Data ◽  
Mean Activity Coefficients

The freezing-point depressions of aqueous solutions of the homologous series RNH3Br, where R varies from ethyl to n-octyl, and of sodium decanoate were determined and used to calculate osmotic and mean activity coefficients. In the case of the surfactants octylamine hydrobromide and sodium decanoate, the pre- and post-micellar regions were covered. Activity data at higher temperatures were calculated using previously published thermochemical data. Some difficulties arise in the critical micellar region of sodium decanoate at high temperatures as a result of the large concentration and temperature dependence of the heat capacity data. The activities from freezing point data are compared with those obtained from specific electrodes.

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