直接法难以得到目标离子液体，必须使用两步合成法。两步法制备离子液体的应

The direct method is difficult to obtain the target ionic liquid, and a two-step synthesis method must be used. The two-step method for preparing ionic liquids has many applications. The preparation of commonly used tetrafluoroborate and hexafluorophosphate ionic liquids usually adopts a two-step method. First, the halogen salt containing the target cation is prepared by quaternization; then the target ion is used to replace the halogen ion or Lewis acid is added to obtain the target ionic liquid. In the second step reaction, when using metal salt MY (usually AgY), HY or NH4Y, Ag salt precipitation or amine salt, HX gas is easily removed, strong protonic acid HY is added, the reaction requires low temperature stirring Carry out, then wash to neutrality with water for many times, extract the ionic liquid with organic solvent, and finally remove the organic solvent in vacuum to get pure ionic liquid. In particular, in the process of exchanging the X-(halogen) anion with the target anion Y, the reaction must be completed as much as possible to ensure that no x. anion remains in the target ionic liquid, because the purity of the ionic liquid is Characterization of applications and physicochemical properties is essential. The synthesis of high-purity binary ionic liquids is usually prepared by anion exchange using ion exchange resins in an ion exchanger. In addition, the Lewis acid (MY) is directly combined with the halide salt to prepare [cationic] [MnXny+l] type ionic liquids, such as the preparation of chloroaluminate ionic liquids, as described in the properties of ionic liquid The acidity of the ionic liquid can be adjusted as needed.

Direct method is difficult to obtain the target ion icing, must use a two-step synthesis method. There are many applications for the preparation of ionic liquids by two-step method. The preparation of commonly used tetrafluoroborate and hexafluorophosphate ionic liquids is usually done by two-step method. First, a brine containing the target cation is prepared by a seasonal amine reaction, and the target ion son is then replaced with the target anion or lewis acid is added to obtain the target ionic liquid. In the second stage of reaction, the use of metal salt MY (commonly used agY), HY or NH4Y, the production of Ag salt precipitation or amine salt, HX gas is easy to be removed, add edgacid HY, the reaction requires at low temperature stirring conditions, and then many times washed to neutral, with organic solvent extraction of ionic liquid, and finally vacuum removal of organic solvents to obtain pure liquid ions. It is particularly important that in the process of exchanging X-(halogen) ions with the target anion Y, the reaction must be completely performed as far as possible to ensure that no x. anionremains remain in the target ionic liquid, as the purity of the ionic liquid is essential for its application and the characterization of physical and chemical properties. The synthesis of high-purity binary ion liquids is usually prepared in an ion exchanger using ion exchange resin through anion exchange. In addition, the direct combination of Lewis acid (MY) with the brine can be prepared to prepare the type of ionic liquid, such as chloralacid ionic liquid preparation is the use of this method, as described in the nature of the ionic liquid, the acidity of the ethnofluidic liquid can be adjusted as needed.

It is difficult to obtain the target ionic liquid by direct method, so two-step synthesis method must be used. There are many applications of two-step method to prepare ionic liquids. Two steps are usually used to prepare tetrafluoroborate and hexafluorophosphate ionic liquids. First, the halide containing the target cation was prepared by the quaternization reaction, then the halide ion was replaced by the target anion or Lewis acid was added to obtain the target ionic liquid. In the second step, metal salt my (usually AGY) is used. When hy or NH4Y is used, Ag salt precipitate or amine salt and HX gas are easy to be removed. Strong protonic acid hy is added. The reaction is required to be carried out under the condition of low temperature agitation, and then washed to neutral for many times. The ionic liquid is extracted by organic solvent, and finally the organic solvent is removed by vacuum to get pure ionic liquid. In particular, in the process of exchanging X - (halogen) anions with the target anion y, the reaction must be as complete as possible to ensure that no X. anions remain in the target ionic liquid, because the purity of the ionic liquid is essential for its application and the characterization of physical and chemical properties. The synthesis of high purity binary ionic liquids is usually carried out by ion exchange resin through anion exchange in an ion exchanger. In addition, Lewis acid (my) can be directly combined with halide to prepare [cation] [mnxny + l] type ionic liquid. For example, the preparation of aluminate chloride ionic liquid is based on this method. As described in the properties of ionic liquid, the acidity of ionic liquid can be adjusted as required.