In order to facilitate access and comparison of the basic operations commonly performed in organic chemistry experiments, Rebaud Intermediate Research Center concentrates here on the instrumentation for reflux, distillation, gas absorption and stirring operations.

　　I. Reflux device

　　Many organic chemical reactions need to be carried out near the boiling point of the solvent or liquid reactants in the reaction system, and then reflux devices are used (see Figure 2.6). Figure 2.6 (1) is the ordinary heating reflux device; Figure 2.6 (2) is the moisture-proof heating reflux device

　　Figure 2.6(3) is a reflux device with the absorption of gas generated in the reaction, suitable for reflux with water-soluble gases (such as: HCl, HBr, SO2, etc.) generated by the experiment; Figure 2.6(4) is a device that can be added dropwise to the liquid at the same time when reflux. Before reflux heating should be put zeolite, according to the boiling temperature of the liquid in the bottle, you can choose the water bath, oil bath or asbestos net direct heating and other methods.

　　Under the conditions allowed, generally do not use the asbestos net across the direct heating with open flame. The rate of reflux should be controlled in the liquid vapor infiltration of no more than two balls is appropriate.

　　Second, the distillation device

　　Distillation is a common method to separate two or more liquids with a large difference in boiling points and to remove organic solvents. Several commonly used distillation devices (see Figure 2.7) are available for different requirements. Figure 2.7 (1) is the most commonly used distillation device, due to the outlet of this device and the atmosphere, may escape from the distillate vapor, if the distillation of volatile low-boiling liquid, you need to receive the branch pipe connected to the rubber tube, leading to the water tank or outdoor. The mouth of the branch pipe is connected to the dry tube, can be used as a moisture-proof distillation. Figure 2.7 (2) is the application of air condenser distillation device, commonly used for distillation of liquid boiling point of 140 ℃ or more. If a straight water condensate tube is used, the condensate tube will blow up due to the high temperature of the liquid vapor. Figure 2.7 (3) for the distillation of a larger amount of solvent devices, as the liquid can be added continuously from the dropping funnel, both to adjust the speed of the drop and evaporation, but also to avoid the use of larger distillation bottles.

　　Third, the gas absorption device

　　Gas absorption device (see Figure 2.8), used to absorb the reaction process generated by irritating and water-soluble gases such as: HCl, SO2, etc.). Figure 1.8 (1) and 1.8 (2) can be used as a small amount of gas absorption device.

　　The glass funnel in 2.8(1) should be tilted slightly so that the funnel mouth is half in the water and half on the water surface. This prevents the gas from escaping and the water from being sucked back into the reaction flask. If there is a large amount of gas generated during the reaction or gas escapes quickly, you can use the device in Figure 2.8(3), water from the upper end of the inflow (you can use the water flowing out of the condenser tube) to draw the bottle, overflowing in a constant plane. The thick glass tube just reaches into the water surface and is sealed by the water to prevent the gas from escaping into the atmosphere. The thick glass tube in the figure can also be used in place of the Y-shaped tube.

　　IV. Stirring device

(1) Stirring device

　　When the reaction is carried out in a homogeneous solution, it can generally be done without stirring, because there is a certain degree of convection in the solution when heated, thus keeping all parts of the liquid uniformly heated. If it is a non-homogeneous reaction, or one of the reactants is gradually added drop by drop, in order to make it as quickly and uniformly mixed, in order to avoid local over-concentration and overheating and lead to other side reactions or decomposition of organic matter; sometimes the reaction products are solid, such as no stirring will affect the smooth progress of the reaction; in these cases are required to stirring operation. In many synthetic experiments, if you use stirring device can not only better control the reaction temperature, but also shorten the reaction time and improve the yield.

　　Commonly used stirring devices are shown in Figure 2.9. Figure 2.9(1) is an experimental device that can simultaneously stir, reflux and add liquid from a dropping funnel; the device in Figure 2.9(2) can also measure the temperature of the reaction; Figure 2.9(3) is a stirring device with a drying tube; Figure 2.9(4) is a magnetic stirring.

　　(2) Sealing device

　　Mixer shaft head and stirring rod can be connected by two sections of vacuum rubber tube and a section of glass rod, so that the stirrer conduit does not wear or break (see Figure 2.11)

　　(3) Stirring bar

　　The stirring rod used in stirring is usually made of glass rods, many styles, commonly used in Figure 2.12. of which (1), (2) two can be easily bent with glass rods. (3), (4) more difficult to make. The advantage is that it can reach into the bottle with a narrow neck, and the mixing effect is better. (5) is a barrel-shaped stirring bar, suitable for two-phase immiscible system, its advantage is smooth stirring and good stirring effect

Fifth, the instrumentation method

　　Organic chemistry experiments commonly used in glass apparatus, generally used iron clamps will be fixed in order to the instrument on the iron frame. Iron clamps should be attached to the double clamp rubber, velvet and other soft substances, or wrapped with asbestos rope, cloth, etc.. If the iron clamps directly on the glass instruments, it is easy to clip the instrument bad.

　　Clamp glassware with iron, first with the left hand fingers will be double clamp, and then tighten the iron clamp screws, to be clamped fingers feel the screws touch the double clamp, you can stop the rotation, so that the clamps are not loose and not tight.

　　Reflux device [Figure 1.6 (2)] as an example, the device first according to the heat source height (generally based on the tripod height) with iron clamps round bottom flask neck, fixed vertically on the iron frame. Iron frame should be right outside the laboratory table, do not skew. If the iron frame is skewed, the center of gravity is not consistent, the device is not stable. Then the lower end of the spherical condensate tube is facing the mouth of the flask with iron clamps fixed vertically above the flask, and then relax the iron clamps, the condensate tube down, so that the grinding mouth grinding plug tight, and then the iron clamps slightly tightened, fixed condensate tube, so that the iron clamps are located in the middle of the condensate tube on some. Use a suitable rubber tube to connect the condensate, the water inlet at the bottom and the water outlet at the top. Finally, install the drying tube at the top of the condensate tube according to 1.6(2).

　　The general rule to follow for installing the instrument is:

　　(1) Bottom first, then top, left to right.

　　(2) correct, neat, stable and upright; its axis should be parallel to the edge of the laboratory table.