Sodium methoxide is an important chemical raw material, mainly used as catalyst, condensing agent and analytical reagent. It is an intermediate and raw material for the production of chemical products such as dyes, pigments, pharmaceuticals, spices and pesticides. In addition, sodium methoxide is used in oil processing and fur. There is also a lot of consumption in processing. Since sodium methoxide easily reacts with water to generate sodium hydroxide and methanol, the main impurity in sodium methoxide is sodium hydroxide. In order to know whether the produced sodium methoxide meets the standard, it is necessary to measure the content of sodium methoxide, which requires us to find a method for the determination of sodium methoxide.
According to the Williamson reaction, sodium alkoxides can react with halogenated alkanes in the corresponding alcohol solution, and the halogen atoms are replaced by alkoxy groups to form ethers.
According to this principle, when determining the content of sodium methoxide, we can first allow sodium methoxide to react with halogenated alkanes, convert them into ethers and sodium salts, and then measure the content of sodium hydroxide by acid-base titration. In addition, we let sodium methoxide react with water to convert all into sodium hydroxide, and also measured the content of all sodium hydroxide at this time by the method of acid-base titration, thus, we obtained the total amount of sodium hydroxide and sodium methoxide. Then the difference between the two can be obtained to obtain the content of sodium methoxide.
Since chloroform and sodium methoxide can be carried out at normal temperature and pressure, and excess chloroform is used in the reaction, the two can react rapidly. After the reaction, the chloroform and the resulting ether can be distilled off with a boiling water bath.
By this method, the content of sodium methoxide and sodium hydroxide can be measured. Since the sodium methoxide sample only contains three substances, namely sodium methoxide, sodium hydroxide and water, the water content can also be obtained.