Cryoscopic Determination of Purity of Highly Reactive Substances

Abstract

A freezing point apparatus was constructed of glass and noble metals for assaying the purity of reactive substances.The sample is stirred by a platinum-iridium stirrer sealed within a closed glass system. An iron armature protected by gold or platinum is attached to the upper portion of the stirrer. A solenoid encased in iron, mounted and guided outside the glass wrall of the

Purification by automatic gas chromatography

“…The purities of the first two compounds were determined by the fr eezing point m ethod [5,6,7] before and after purification. The analyses indicated that before purification the toluene was 99.4 mole percent and the ethylbenz ene 99.1 mole percent pure.…”

Purity analysis of highly purified materials by time-temperature cryometry

“…The apparatus and general experimental details discussed in this paper are modifications of those discussed in references [1, 4, and 5]. The success of any time-temperature cryometric determination of purity is dependent upon introduction of the sample without contamination, establishment of good thermodynamic and thermal equilibrium during the freezing process, and proper analysis of the experimental data.…”

“…Enclosed freezing point cells [4], improved sample transfer [5], and a new method of analyzing data [6] have greatly improved the precision and accuracy of the time-temperature cryometric analysis.…”

Purification of substances by a process of freezing and fractional melting under equilibrium conditions

“…The first material collected is the least pure and the last portion most pure. In its downward flow , the liquid 5 from th e melted crystals bathes and washes each succeeding crystal surface. The less pure material wetting the crystal surface is progressivel:"T displaced by liquid of higher purity.…”

“…Nonvolatile samples are transferred as liquid s. They are scaled under their own vapor pressure in inverted breakoff tip ampoules [5], which are atta,checl to an opening into the chamber below N in the figure. The evacuation and subsequen t r emoval of the em pty ampoule and the manifold are similar to that described for the volatile samples.…”