Original Title: Common Reaction Devices for Organic Experiments 1. Water-free and oxygen-free operation device Chemical experiments often need to be carried out in the absence of water and must be kept at a pressure comparable to that of the atmosphere. Therefore, acid or basic drying tubes are used to prevent moisture in the air from entering the experimental system. For example, the preparation of Grignard reagent and its related reactions, Friedel-Crafts reaction, as well as the use of strong alkaline, strong water absorption reagents, such as sodium alkoxide, alkyl sodium, phosphorus pentoxide and other experiments need to avoid the entry of water vapor. Moreover, some experiments require the absence of oxygen in addition to the absence of water. At this time, inert gases such as N2 and argon are often used. Air, oxygen, water, carbon dioxide, etc. Are expelled by this gas stream. For example, the preparation of butyl lithium and its related experiments,50l rotovap, the treatment of anhydrous and oxygen-free solvents, etc. The following figures show several representative experimental devices, which can be used for various experiments without water or oxygen. Device 1: It can isolate the contact between the reaction system and the atmosphere, and prevent the device from cracking due to the pressure difference between the reaction system and the atmosphere caused by sealing. Unit 2: Can handle multiple solvents. Is convenient and safe, can be heated and refluxed, and can take out the processed solvent at any time. The device 3 can be used for carrying out various water-free and oxygen-free reaction experiments. A continuous flow of inert gas is not required. The nitrogen stored in the balloon gives the reaction system a slight positive pressure,hemp extraction centrifuge, which prevents air from entering. Expand the full text Packing 4: In this case, it is necessary to use a reflux condensing device to continuously condense the vapor in the condensing tube and return it to the reactor, so as to prevent the escape and loss of substances in the reactant. Three. Reflux dropping device Some reactions are more violent in the reflux state, and the heat release is large. If the reactants are put in at one time, the reaction will be difficult to control; Or in some reactions, in order to control the selectivity of the reaction, the reactants also need to be added in batches. In this case, rotovap distillation ,wiped film distillation, a reflux dropping device with a dropping funnel is used to slowly drop one of the reactants. 2. No chemical reaction with water under co-boiling ； 3. At At about 100 ℃,cbd centrifugal extractor, there is a certain vapor pressure, generally not lower than 667 Pa (5mmHg). If it is lower than this value and steam distillation is necessary, superheated steam distillation should be used. Return to Sohu to see more Responsible Editor:. toptiontech.com
Common reaction devices
