Vitrinite reflectance (Ro,) is regarded as one of the most, ifnot the most, powerfultools available to petroleum organic geochemistry. Yet major recognized and unrecognized problems exist concerning use of the technique. One such unrecognized problem is a major suppression of Ro by significant concentrations of exinite macerals (Type I and Type II kerogen) in association with vitrinite macerals.
Ro values have been, and are, for the most part, read from exinite‐rich sediments examined in organic geochemical studies. This has led to the establishment of R0 values of 0.6 (± 0.1) and 1.35 corresponding, respectively, to the regional rank necessary for the onset of significant hydrocarbon generation and for the thermal destruction of petroleum (“oil deadline”). These uniformly quoted Ro values, derived from exinite‐rich (hydrogen‐rich) kerogens, would have far different values if Ro had been read from vitrinite‐rich (oxygen‐rich) kerogen at the same regional rank. The serious miscalibration of the regional ranks necessary for the onset of significant petroleum generation from exinite‐rich kerogen and for the “oil deadline” have major implications for assessment of frontier areas of possible petroleum reserves as well as for petroleum exploration in general and worldwide and basin‐by‐basin resource assessment of undiscovered petroleum reserves.
Thermal-conductivity measurements have been carried out over the temperature range 300° to 475°K with an eight-cell hot-wire thermal-conductivity apparatus. The thermal conductivities of the deuterated gases are greater than those of their unsubstituted counterparts at the higher temperatures (presumably because of their higher heat capacities). Conductivities of the equimolar mixtures lie about midway between the conductivities of the pure components. Results are analyzed to test a recent hypothesis that a resonant exchange of rotational quanta causes the thermal conductivity of a polar gas to seem anomalously low in relation to its viscosity. These results are consistent with this hypothesis, the only qualification being that near-resonant exchange is also important.
the precipitate was separated into twelve bands. Absorption spectra and reactions with alcoholic potassium hydroxide (6) showed the presence of two dicarbonvl and ten monocarbonyl derivatives.The fraction from the deaerator with the raw tomato odor. Dob, was shown by the chromatostrip technique of Kirchner et al. ( 5) to contain at least one unsaturated compound and no aldehydes. T2d, the fraction with green tomato odor from the tube evaporator, also contained one or more unsaturated compounds and no aldehydes.Thus, unsaturated compounds were shown to be present in the fractions with typical tomato odor and with raw and green tomato odor. Also, by their odors, spectra, and in some instances the formation of derivatives, unsaturated compounds of a terpene nature, such as citral, were indicated to be present in other fractions modifying the fractions with tomato odor. The oxidation and polymerization of these unsaturated compounds may offer at least a partial explanation for the flavor deterioration of stored tomato products when this occurs.
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