Method for preparing sodium salicylate through carboxylation reaction of sodium phenate

Abstract

The invention relates to a method for preparing sodium salicylate through carboxylation reaction of sodium phenate, which comprises the following steps: by taking acetone as a solvent and sodium phenate and carbon dioxide as raw materials, dissolving sodium phenate in acetone to prepare a sodium phenate solution, and carrying out carboxylation reaction on sodium phenate and carbon dioxide in a high-efficiency gas-liquid dispersion mixing reactor to obtain the sodium salicylate. And carrying out reduced pressure flash evaporation and gas-solid separation on the reacted material to obtain sodium salicylate. Acetone is adopted as a solvent for carboxylation reaction of sodium phenolate, the carboxylation reaction of sodium phenolate and carbon dioxide is changed from traditional gas-solid multi-phase reaction to gas-liquid multi-phase reaction, meanwhile, an efficient gas-liquid dispersion mixing reactor is adopted, the gas-liquid ratio is increased, and meanwhile the conversion per pass is increased. The unit operation process is a sealed circulating system, the whole process is safe and environment-friendly, the solvent can be recycled, and the process is a clean production process for continuously producing sodium salicylate.

Description

technical field [0001] The invention relates to a method for preparing sodium salicylate by carboxylation of sodium phenolate in an acetone solution, and a process technology for preparing sodium salicylate by using sodium phenolate and carbon dioxide as raw materials. First, the sodium phenate was dissolved in the solvent acetone to prepare a sodium phenate solution, and then the obtained sodium phenate solution was subjected to a gas-liquid phase carboxylation reaction with carbon dioxide in a high-efficiency gas-liquid dispersion mixing reactor. After the reaction, the material was flashed under reduced pressure. Evaporate to obtain sodium salicylate. It belongs to the technical field of fine chemicals and chemical engineering. Background technique [0002] 1. Sodium Salicylate [0003] Sodium salicylate, also known as sodium o-hydroxybenzoate, 2-hydroxybenzoic acid monosodium salt, sodium salicylate and sodium salicylate, etc., the molecular formula is C 7 H 5 NaO 3...

AI Technical Summary

Problems solved by technology

[0004] 2. Existing gas-solid phase carboxylation synthesis process of sodium salicylate and the main problems

Therefore, there is a contradiction between carboxylation reaction rate and selectivity, and how to realize the rapid and effective reaction of gas phase reactant carbon dioxide and sodium phenate under high selectivity conditions is a common technical problem.

[0008] (2) Gas-solid phase reaction system: During the carboxylation reaction of sodium phenate and carbon dioxide to generate sodium salicylate, carbon dioxide is a gas phase material, and sodium phenate is a solid phase material, which is a gas-solid phase reaction system, and there must be a reaction Low rate, long reaction time, difficulty in heat removal during the reaction process, easy local overheating to produce by-products, etc.

[0009] (3) reaction selectivity is low, causes poor product quality: easy to generate by-products such as sodium p-hydroxybenzoate in the reaction process, and product separation refining difficulty is difficult to obtain high-quality salicylic acid with sodium salicylate

[0010] (4) The preparation problem of fine particle sodium phenate: in order to improve the rate that sodium phenate and carbon dioxide generation carboxylation reaction generate sodium salicylate, adopt the method for reducing sodium phenate particle to be the most effective method that improves carboxylation reaction speed and conversion rate , in order to prepare fine particle sodium phenate, there must be a technical problem in the preparation of fine particle sodium phenate

[0011] (5) Continuous steady-state operation control is difficult: because carbon dioxide and sodium phenate are gas-solid phase exothermic reaction systems, there must be problems of reaction operation process control and reactor operation instability

[0012] (6) Poor safety and reliability of the process: the reactant sodium phenate is dehydrated into a dry powder and is easy to burn and explode, and there are potential safety hazards of burning and explosion in the preparation process of fine particle sodium phenate