What is the crystallization point of pure benzene? With what test?

The crystal point is one of the important physical constants of a substance. The crystal point of a pure substance is fixed. If it contains impurities, the crystal point will decrease.
The crystallization point of pure benzene is 5.53℃.
The average crystallization point of coking benzene in a plant is 4.84℃, indicating that the content of coking benzene impurities is high.
The coking benzene samples were taken for chromatographic analysis, and the analysis results were shown in the figure below.
The pure benzene content is 98.16%, the impurity content is 1.84%, the impurity type is more than 13 kinds.
SH406B automatic crystal point analyzer (developed and produced by Shandong Shengtai Instrument Co., LTD.) applies the standard GB/T3145-1982 benzene crystal point determination, GB/T 3069.2-2005 naphthalene crystal point determination, GB/T 3710-2009 industrial phenol, phenol crystallization point determination, GB/T7533-1993-2005 organic chemical products crystallization point determination, GB/T618-2006 chemical reagent crystallization point determination.
Determination of crystallization point of plasticizers.
(Benzene crystallization point meter, phenol crystallization point meter, phenol crystallization point meter, freezing point meter, plasticizer crystallization point meter)
Ii. Compliance with standards:
1. Upgrade to 7-inch TFT color LCD display;
2. Refrigeration mode: fully enclosed and efficient refrigeration compressor.
3. Number of test groups: 1 group (2 groups can be customized).
4. Detection method: Imported PT100 temperature sensor
5. After upgrading, historical data can be stored for easy query;
At the same time can be equipped with U disk output function.
6, standard micro printer automatic measurement automatic printing
7. If there is no operator after the test, set the automatic shutdown time of the refrigerator within 0-50min to avoid the frequent opening of the compressor and extend the service life of the instrument.
8, including laser printer interface, can be linked to HP1108 laser printer (optional).
9. Date password setting function.
10, standard micro printer automatic measurement automatic thermal printing
11. Equipped with TCP network transmission function
12. Upload and connect to limis system
Technical parameters
1. Power supply: AC220V±10%;
50 hz.
2. Working cold bath: double-layer vacuum glass bath.
3. Cold tank temperature control: +80℃ ~ -10℃.
4. Temperature control accuracy: ±0.01℃.

5. Bath liquid stirring: The stirring motor can stir automatically with a power of 6W and 1200r/min.
6. Refrigeration system: new type refrigeration compressor.
7. Sample agitation: synchronous deceleration motor, 60 times/min.
8. Ambient temperature: ≤30℃.

9. Relative humidity: ≤85%.
10. Overall power consumption: around 1500W.