Preparation device and method of methyl 3-methyl-2-butenoate

Abstract

The invention discloses a device and a method for preparing methyl 3-methyl-2-butenoate. The self-design device comprises a reaction kettle, a reaction reflux and distillation condenser, a rectifyingkettle, a rectifying tower section and a rectifying tower top condenser, the reaction kettle is connected with the reaction reflux and distillation condenser through a pipeline; the reaction reflux and distillation condenser is connected with the rectification kettle through a pipeline; the rectifying kettle is connected with the rectifying tower section; the top of the rectifying tower section isconnected with the rectifying tower top condenser through a pipeline; the rectifying tower top condenser is connected with the reaction kettle through a pipeline. According to the method, the ionic liquid is used as a catalyst for esterification reaction of methyl 3-methyl-2-butenoate, on the base of the self-designed preparation device, the reaction process is carried out synchronously with separation of methyl 3-methyl-2-butenoate and (or) water, an ionic liquid catalyst is repeatedly used for five times, and the average yield of the reaction is 90.7%. The invention provides a safe, economic, green and environment-friendly preparation device and method for industrial scale production of methyl 3-methyl-2-butenoate.

Description

technical field [0001] The invention belongs to the technical field of chemistry and chemical engineering, and in particular relates to a preparation device and method of 3,3-methyl methacrylate. Background technique [0002] 3,3-Methyl methacrylate has a boiling point of 136.5°C under normal pressure and is stable to heat in a neutral environment. It is an important raw material for organic synthesis and is used as an intermediate for medicine and pesticides. For example, it can be used to make isodimensional A acid and piroctone, etc. [0003] At present, in industrial production, 3,3-dimethacrylic acid and methanol are generally mixed, and concentrated sulfuric acid is added as a catalyst, and the reaction is stirred and refluxed at 60-70°C. After cooling, water is added to remove the water layer, sulfuric acid is removed, the organic layer is taken, and water The layers were extracted with dichloromethane, and the organic layers were combined, washed with dilute sodium ...

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Problems solved by technology

[0005] There are many problems in the above-mentioned process in actual production. First, because water is generated in the reaction, the catalyst concentrated sulfuric acid cannot be recycled and used mechanically, and the waste acid produced will bring pressure to the treatment of three wastes; Extraction of solvents increases costs and pollutes the environment; third, the use of desiccants such as anhydrous magnesium sulfate in the process increases the amount of solid waste and brings pressure on the treatment of three wastes; fourth, the esterification reaction itself is a reversible reaction, and the yield must be increased. To make the main raw material 3,3-dimethacrylic acid reach the maximum effective conversion, the better way is to continuously remove the 3,3-dimethacrylate methyl ester and (or) water generated by the reaction during the reaction, so that the problem comes Therefore, the 3,3-methyl methacrylate and (or) water generated by the reaction are constantly removed, and the general method is to continuously distill and remove the 3,3-methyl methacrylate generated by the reaction during the reaction. and (or) water, but due to the relatively low boiling point of methanol, it will be distilled out together during the distillation process, and methanol is the raw material for the reaction. Theoretically, the more amount of formazan in the system, the more favorable the conversion reaction of 3,3-dimethacrylic acid

[0006] Therefore, when the 3,3-dimethacrylate and / or water produced by the reaction are removed by distillation, the methanol will be distilled first, so that the methanol in the reaction system will be reduced, and a certain amount of methanol must be maintained in the reaction system. In this way, methanol must be continuously added. In order to reduce the amount of methanol, methanol must be recovered in time and applied to the reaction system. In order to realize the effective separation of methanol from 3,3-methyl methacrylate and water, it is necessary to add column rectification , directly add a rectification tower on the reaction kettle, while effectively separating methanol, but also want to separate the 3,3-dimethacrylate and (or) water generated by the reaction, a higher kettle temperature (ie reaction temperature ), the high reaction temperature will increase the generation of by-products, and also promote the decomposition of the product 3,3-methyl methacrylate. If the temperature is lowered, only methanol can be separated, but the 3 generated by the reaction cannot be effectively removed. 3-Dimethacrylate and / or water

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