The specific and latent heats of fusion of some vegetable fats and oils

Autor: A. R. Gudheim
Rok vydání: 1944
Předmět:
Zdroj: Oil & Soap. 21:129-133
ISSN: 1558-9331
0003-021X
Popis: The specific heats of several vegetable oils have been determined by a more exact procedure than those which seem to have been used heretofore. Values slightly higher than the literature figures were obtained, that is, an average value of 0.53 was determined as compared to reported results of 0.50. The specific heat of cottonseed oil with respect to temperature increases slightly with elevating temperatures. The specific heats at different temperatures were not determined on the other oils, but likewise, these probably show no significant variation in specific heat with respect to temperature in the range 21° to 100°C. The specific heats of completely solid vegetable fats are believed to be reported for the first time. These values are about the same for such different stocks as completely hardened palm and sunflower oils, and their values are approximately one-half that of the liquid, that is, 0.28 as compared to 0.53. The latent heats of fusion of a number of fats have also been determined by what is thought to be a satisfactory procedure. Theoretical aspects and empirical results are given to show that the latent heat of fusion varies with the temperature when two phases are present, and that for this reason, any references to the latent heat of fusion should be accompanied by temperature limitations. This is not so important, however, when the specimen is completely solid at the temperature in question. The data and graphs presented show the general variation in latent heat of hardened cottonseed oil at one temperature with respect to iodine value.
Databáze: OpenAIRE
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