Laboratory equipment mixer classification and precautions for its use

Stirrer is one of the indispensable instruments for organic chemistry experiments. It can make the reaction mixture more uniform and the temperature of the reaction system more uniform, which is conducive to the chemical reaction, especially the heterogeneous reaction.

There are three methods of mixing: manual mixing, magnetic mixing, and mechanical mixing.

Manual stirring is generally carried out by means of a glass rod. Magnetic stirring uses a magnetic stirrer, and mechanical stirring uses a mechanical stirrer. Magnetic stirrer Because the magnetic stirrer is easy to install, it can be used for continuous stirring. Especially when the reaction volume is relatively small or the reaction is carried out under closed conditions, the use of the magnetic stirrer is more convenient. But the disadvantage is that for some viscous liquids or reactions in which a large amount of solids participate or are generated, the magnetic stirrer cannot be used smoothly. In this case, a mechanical stirrer should be used as the stirring power.

Magnetic stirrer uses the rotation of the magnetic field to drive the rotation of the magneton. Magnet is wrapped in a small piece of metal with a layer of inert material (such as polytetrafluoroethylene, etc.), or it can be self-made: put a piece of 10# iron lead wire into a thin glass tube or plastic tube, and seal at both ends. The size of the magneton is about 10mm, 20mm, 30mm long, and there are longer magnetons. The shape of the magneton is cylindrical, elliptical and circular, etc., which can be selected according to the scale of the experiment.

Mechanical agitator Mechanical agitator mainly includes three parts: motor, agitating rod and agitating sealing device. The motor is the power part, fixed on the bracket, and its speed is adjusted by the governor. The stirring rod is connected to the motor. When the power is turned on, the motor drives the stirring rod to rotate for stirring. The stirring and sealing device is a device that connects the stirring rod to the reactor, which can make the reaction proceed in a sealed system. The efficiency of stirring depends to a great extent on the structure of the stirring rod. The old-style stirring rods introduced are made of thick glass rods. According to the requirements of the size and shape of the reactor, the size of the bottle mouth and the reaction conditions, choose a more suitable stirring rod.

Magnetic stirrer is suitable for mixing and stirring thin liquid materials. Here, briefly introduce a few issues that should be paid attention to during the use of the magnetic stirrer:

1.When using for the first time, first check whether the accessories of the instrument are complete with reference to the instrument manual, such as agitator, power cord, etc.;

2.The speed should be gradually adjusted from low speed to high speed, it is best not to start directly at high speed, so as not to synchronize the stirring bar, causing jumps;

3.It can not be heated without stirring, and the power should be cut off when not working;

4.The instrument should be kept clean and dry, especially do not let the solution enter the machine;

5. If you find that the stirrer jumps or does not stir during stirring, please check whether the beaker is stable and the position is correct;

6.Medium-speed operation can extend the life of the mixer;

7. It is best to be able to connect to the ground when using.