The products obtained by heating p‐terphenyl to 460–480° in a closed tube have been studied and identified. One group of products consists of low‐molecular‐weight hydrocarbon gases and hydrogen; a second decomposition product is diphenyl; there is a third group consisting of quater‐, quinque‐, and sexi‐phenyls. Of these, the following polyphenyls have been isolated and identified: p‐quaterphenyl, 3: 4′‐diphenyldiphenyl, 3‐phenyl‐4′‐(4″‐diphenyl)diphenyi, 4‐phenyl‐3′‐(4″‐diphenylyl)diphenyl, p‐sexiphenyl and 4 : 3′‐bis‐(4″ : 4″‐diphenylyl) diphenyl.Under the influence of heat, p‐polyphenyls combine with each other, chiefly at the m‐positions. An equimolar mixture of diphenyl and p‐terphenyl, after being held at 480° for 2 days, gave several types of m‐quaterphenyls and m‐quinquephenyls which shows that p‐terphenyl breaks down partially to diphenyl which either condenses with itself to form even‐numbered polyphenyls, or reacts with undecomposed p‐terphenyl to form a quinquephenyl.
A procedure is described for the colorimetric determination of small amounts, 0.01 to 0.4 per cent., of cadmium in lkad or lead alloys without prior removal of lead. The common alloying elements do not interfere. For lower percentages of cadmium a portion of the lead must be removed. Detailed alternative procedures are described and extensions of the method for samples containing more or less cadmium are indicated.
Preliminary concentration is necessary before potassium can be determined in the presence of large amounts of sodium ion.Metallic sodium, sodium hydroxide and sodium salts are converted to chloride. Measured, cold, saturated aqueous chloride solutions are treated with dry hydrogen chloride gas, which separates the bulk of the sodium chloride. The residual potassium, calcium and magnesium can then be determined by the usual methods.Calcium and magnesium may also be determined with or without preliminary sodium chloride separation.
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