Purification method of propionaldehyde

Abstract

The invention discloses a purification method of propionaldehyde. The method comprises the following steps: adding a certain amount of a polymerization inhibitor to low-content propionaldehyde, performing stirring and heating distillation, controlling the external temperature and the top temperature, controlling the pressure at the normal pressure, collecting the obtained distillate, and discarding a small amount of rear distillate; adding strong alkali and weak acid salt into the collected distillate, and stirring at normal temperature; and filtering, collecting filtrate, and sealing and storing with nitrogen. The method is simple in process, easy to operate and suitable for preparing high-content propionaldehyde, and the content can reach 99.8% or above. After the polymerization inhibitor or the strong alkali and weak acid salt is added, the influence of polymers and acidic substances can be eliminated, the operable range of the external temperature is relatively large, and the quality of propionaldehyde is not influenced; in the later stage of distillation or rectification, the top temperature can be increased, and the content of propionaldehyde in the distillate can be greatly reduced when the temperature exceeds the set temperature, so that fractions are collected in the top temperature range to obtain high-content propionaldehyde.

Description

technical field [0001] The invention belongs to the technical field of chemical purification, and in particular relates to a method for purifying propionaldehyde. Background technique [0002] Propionaldehyde is an important raw material of organic chemicals, mainly used in the production of n-propanol, propionic acid, trimethylolethane, propionaldehyde oxime and other intermediates, and is also widely used in the production of organic synthesis, pharmaceuticals, pesticides and fine chemicals . [0003] Propionaldehyde is easily oxidized, so it is difficult to preserve for a long time during use. Generally, it is stored in a nitrogen seal. However, due to the presence of dissolved oxygen in propionaldehyde and the influence of the external environment, it is inevitable that some impurities will be produced during the storage process. , such as its own polymerization products, oxidized products, etc., resulting in a decrease in the content of propionaldehyde. In organic synt...

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Problems solved by technology

[0003] Propionaldehyde is easily oxidized, so it is difficult to preserve for a long time during use. Generally, it is stored in a nitrogen seal. However, due to the presence of dissolved oxygen in propionaldehyde and the influence of the external environment, it is inevitable that some impurities will be produced during the storage process. , such as its own polymerization products, oxidized products, etc., resulting in a decrease in the content of propionaldehyde. In organic synthesis, propionaldehyde generally participates in the structure construction of target molecules, and it is difficult to meet the use requirements after its content is reduced.

[0004] At present, there are very few relevant materials about the purification of propionaldehyde in the literature or other patents. The purification device of propionaldehyde mentioned in the patent CN104086387A requires a specific device and the operation process is cumbersome, and the required conditions are also relatively harsh.

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