separation of b oron i sotopes

Separation of Boron Isotopes

吴孝琴2012.7.28

Content

• 1.Scope of investigation• 2.Determination of isotopic seperation factor procedure for measuring α corrections

• 3.Determination of physical constants solubility of BF3

vapor pressure of BF3 complexes melting point rate of exchange

Scope of Investigation

其中大部分为醚类，另外还有苯酚，硫醚，四氢呋喃，硒，硝基苯，硫醇

Guides for Study

1.同位素平衡常数随温度的变化2.三氟化硼在络合剂中的溶解度3.卤化物及有机物的蒸汽压4.卤化物和络合物的交换速度5.络合物的熔点

Determination of Isotopic Seperation Factor

If the amount of BF3 in the gas phase is kept small compared to the amount of BF3 , as complex in the liquid phase, then the second relationship above may be assumed, for mathematically it can be shown that essentially all the isotopic change takes place in the gas phase.

Determination of Isotopic Seperation Factor- procedure for measuring α

Determination of Isotopic Seperation Factor- corrections

In most cases measured boron α are not true equilibrium constants for the isotopic exchange reaction. The effective measured a may be written:

Determination of Isotopic Seperation Factor- corrections

phenol-BF3

methyl sulfide-BF3

triethyl amine-BF3

anisole-BF3, no excess BF3 was dissolved and measured α are taken as true equilibrium constants.

Determination of Physical Constants-Solubility of BF3

Determination of Physical Constants-vapor pressure of BF3 complexe

After a known amount of dry, purified organic was admitted to a 50 ml reaction flask in the vacuum system, it was frozen and out-gassed. A predetermined amount of BF3 was admitted to the flask and allowed to react slowly with the organic. The flask and contents were then tempera ture equilibrated and a pressure measurement was made. The temperature was changed and the process repeated. Pressure measurements were made both ascending and descending the temperature scale.

Determination of Physical Constants-melting point

Melting points of the 1:1 addition compounds were determined both from cooling curves and by direct observation of the freezing-thawing cycle.

Determination of Physical Constants-rate of exchange

A rapid rate of B10- B11 exchange is a necessary criterion for any system used in a boron isotope separation process. Not only must the isotopic equilibrium constant differ from unity, but the rate of isotopic exchange must be so rapid that exchange be complete as soon as the two phases are contacted in a suitable apparatus, whether the phases be gas-gas, gas-liquid, or liquid-liquid.

Determination of Physical Constants-rate of exchange

Thank you 吴孝琴

2012.7.28