环己烷-乙醇二相图

Binary liquid-vapor phase diagram
1.Objectives
1.1To draw the binary liquid – vapor phase diagram of cyclohexane –
ethanol at normal atmosphere, and determine the azeotropic point and composition in the azeotropic mixture.
1.2To learn the principle and method of measuring the refraction of a
liquid by refractometer.
2.Principle
The binary liquid is composed of a mixture of two kinds of substance.
If the two components are miscible from 0~100% proportions, it is called a totally miscible binary liquid system. The phase rule is:
F=K-Φ +2
K-the number of components of components;
Φ-the number of phases;
F-the number of degrees of freedom;
2-depends on the temperature and the pressure of system
For a system of two components (A and B) at a given pressure, the phase rule is: F = 3 - Φ .For a liquid of two components, when the gas phase and liquid phase is in equilibrium,Φ=2,F = 1.T is a function of x proportion of the liquid .It could be constant at a given concentration.
To measure the temperature at boiling point of a solution of given
concentration, meanwhile to determine the concentration of liquid and the proposition of gas at boiling point, an experimental point of T-x-y could be obtained.
1.thermometer;
2.inlet orifice;
3.heater;
4.sampling orifice;
5.fractional liquid.
3.Apparatus and Reagents
Ebulliometer; mercury thermometer (50 ~100℃,±0.1℃);Abbe Refractometer; long burette and normal burette; AC current power supply.
Cyclohexane(A.R.); absolute ethanol(A.R.);cyclohexane – ethanol standard sample (cyclohexane composition , ω/ω%, precisely to 0.5%) : 0%;10%;20%;30%;40%;50%;60%;70%;80%;90%;100%;cycrohexan e–ethanolsolution(cyclohexane composition,
ω/ω%):0%;10%;20%;40%;50%;60%;70%;80%;90%;98%;100%.
1.eyepiece with crosshairs;
2.2compensator knob(消色散手柄);
3. Circulating water intake;
4. Thermometer;
5.refracting prism(测量棱镜)；
6.gemel(铰链);
7.illuminating prism(辅助棱镜);
8.inlet orifice(加液槽);
9. Reflector;
10. Reading telescope;
11.rotation axis(转轴);
12.cover of dial（刻度盘罩）;
13.closed knob(闭合旋钮);
14.the pedestal(底座).
4.Experiment
4.1Learn the operation procedure of Abbe refractometer, and measure
the refractive index of cyclohexane – ethanol standard sample.
4.2Fill the dry and clean bottle about one –half full with the 98%
cyclohexane of cyclohexane – ethanol mixture.
4.3Connect the circulating cool water. Adjust the knob of power at AC
current power supply. Heat the liquid to boiling gently and refluxing.
4.4Incline the condensed liquid back to the flask 2~3 times. Stop heating
until the temperature could be maintained at a constant and read it.
Use a dry and clean long pipette to suck the condensed liquid. Use another pipette to suck the liquid in the flask via the inlet orifice and measure its refractive index as quickly as possible.
4.5Pour the solution into original vessel. Repeat the step 4.3, step 4.4
and step 4.5 and measure the boiling point and refractive indices.
5.Notes
5.1The system is directly heated by a resistance wire coil dipped in the
liquid mixture in order to reduce over – heating of the system when boiling and prevent from bumping.
5.2Read the value on thermometer after the temperature has been
maintained at constant.
5.3The electric heater should be turned off before sampling.
5.4The measurement of refractive index of sample should be carried
through as quickly as possible to prevent them volatilization so as to change the position.
5.5Using the Abbe refractometer in the direction of the operation manual
strictly. The measuring prism is constructed out of soft glass that is easily scratched.
6.Data
336
338340342344346348
350352354356T /K
Y C2H5OH
X C2H5OH
1.30.0℃时，已知组成的环己烷（B ）-乙醇（A ）二组分系统的折射率。

（温度：30.0℃±0.1℃）。