In the experimental device of organic chemistry, the common purification means include evaporation and rotary purification of organic matter, and distillation device also has such conditions.In the process of students' experimental operation, it is a big problem that they can not control the purification degree of experimental materials and resource allocation.Unable to control the experimental results, which is a great disadvantage for students to conduct normal experiments in the future, and the improvement and optimization of experimental devices is an important research topic to improve the traditional instruments and equipment step by step, so as to maximize the efficiency and ensure that students can speed up their proficiency in the experimental process.During the operation of the rotary evaporator, due to the high water temperature in the water bath and the continuous evaporation of water, you have to check it once in 30min in the experimental operation. When the water level is low, you have to add water to prevent the water from evaporating dry.In this way, the wasted time and observation frequency of an experiment are very large. A temperature sensor is configured above the water bath tank, which can not only ensure the adjustment of temperature and the control of evaporation frequency, but also enable students to flow in the sewage in the circulating water vacuum pump during organic purification, so as to ensure the experimental results as much as possible.The vacuum extraction hole and the rotating bottle are sealed and depressurized in the experiment in an arc structure, so that the air pressure can be decelerated in the original 400 ~ 600mmhg. If students encounter blocking problems in the configuration process, they can remove a large number of residues through the vent hole.
During the experiment, pay attention to the following matters to ensure the completion of the experiment:
1）Be sure to turn on the circulating water vacuum pump first, then put the bath pot under the rotating bottle during heating, and rotate the heating hand wheel to rise to the required height.Add purified water or heat conducting silicone oil to 2 ~ 3cm below the pot, and adjust the temperature through the temperature controller.In the process of indoor operation, to prevent the air flow rate from being too fast, it is necessary to clean the rotating flask twice in the first experiment, so as to ensure that other chemicals will not appear when the bath pot is heated.
2）Record the temperature of the water bath tank with the sensor provided by the instrument, and control the temperature of the separation solution with the self-made temperature sensor ABC, and the set value is (50 ± 5) ℃.In the first experiment, students set two kinds of flasks of 500ml and 1000ml according to the standard configuration. After putting the solution into the flask, they work according to the normal requirements. The timing starts when the system is balanced. Different from the usual, during the first experiment, the temperature of the separation solution should be recorded every 10min, so as to ensure the timing of the completion speed of the experiment.
3）Since the vacuum suction hole connected between the self-made temperature sensor and the rotating bottle is improved compared with the traditional device, the pressure should be reduced before starting the motor.At the end, stop the motor first and then ventilate to prevent the rotating bottle from falling off during rotation.