Continuous production method and device for preparing propionic acid through air oxidation of propionaldehyde

Abstract

The invention relates to a continuous production method and device for preparing propionic acid through air oxidation of propionaldehyde. The method comprises the steps that propionaldehyde enters a reactor through a liquid phase inlet in the bottom of a first-order oxidation reactor and makes contact with and is mixed with some compressed air, a majority of propionaldehyde in the raw material is converted into propionic acid through an oxidation reactor, a first-order oxidation product containing a small amount of propionaldehyde continuously enters a second-order or multi-order oxidation reactor and is continuously subjected to the oxidation reaction with the compressed air, and finally the propionic acid with the high-purity is generated. The device comprises two or more oxidation reactors connected in series, a condenser is arranged on the top of each oxidation reactor, and gas phase pipelines and backflow pipelines are arranged between the oxidation reactors for connection. A tail gas processing device is arranged behind each oxidation reactor. A gas phase pipeline is arranged between each condenser and the corresponding tail gas processing device for connection. The reaction conditions are mild, the product yield is high, the product quality is good, the propionaldehyde conversion rate is larger than 98.5%, the selectivity of the propionic acid is larger than 97.5%, and the product purity is larger than 99.5%.

Description

technical field [0001] The invention is a production process for preparing propionic acid through continuous oxidation reaction using propionaldehyde and air as raw materials; in particular, it relates to a continuous production method and device for preparing propionic acid by air oxidation of propionaldehyde. Background technique [0002] Propionic acid is a colorless and transparent liquid with a strong pungent odor, which is miscible with water, ethanol, ether, chloroform and other organic acids, and can be used to prepare propionate, ester, acid chloride, amide and acid anhydride. Propionic acid esters are important solvents and spices, and propionyl chloride and propionic anhydride are important pesticide and pharmaceutical intermediates. Propionic acid and its derivatives have been widely used in agriculture, textile, food, medicine and other industries, and its use is expanding, and its consumption is increasing year by year. [0003] At present, there are three kin...

AI Technical Summary

Problems solved by technology

This method uses external circulation heat exchange to remove the heat of reaction, which increases the complexity of the process. Due to the large amount of external circulation (generally more than 20 times the amount of feed), the increased energy consumption is also considerable.

The preferred oxygen-aldehyde molar ratio proposed by the patent is 0.55-0.90:1, such a high oxygen-aldehyde molar ratio is unsafe when air is the oxidant

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