온도표준 기준 물질로의 개발을 위한 pivalic acid의 고순도 정제

Purification of pivalic acid : its evaluation as a temperature standard reference material

Pivalic acid를 진공 증류 및 zone refining을 이용 고순도로 정제하여 온도 표준 기준 물질로의 개발 가능성을 시험하였다. melting plateau curve를 이용하여 99.9997% 순도의 pivalic acid cell들의 삼중점을 측정한 결과 $35.956\pm 0.003^{\circ}C$를 얻을 수 있었다. 이상의 정밀도를 갖는 pivalic acid 삼중점 cell들은 고정밀도를 요구하지 않는 일반 thermistor 온도계류의 보정용으로 충분히 사용 가능한 것으로 판단된다.

The suitability of pivalic acid was confirmed as a secondary temperature standard material. Triple-point cells of pivalic acid were obtained by using combined process of vacuum distillation with zone refining. A detailed description of the purification process was given. The melting curves were used as criteria for determination of purities of pivalic acid. Triple points of these cells with purity of 99.9997% were measured to be $35.956\pm 0.003^{\circ}C$ by using the melting plateau curves. Thus the triple point cells of pivalic acid appear to be able to use for the calibration of thermistor thermometers with moderate precision.