Continuous production method of propyl acetate

Abstract

The invention relates to a continuous production method of propyl acetate, and is characterized by comprising the following steps: adding ionic liquid dissolving inorganic compound of the Lewis acid into the glacial acetic acid and the normal propyl alcohol as the catalyst; heating the components in an esterification kettle for esterification reaction; adding the mixed raw material of the glacial acetic acid and the normal propyl alcohol with the same proportion into the esterification kettle continuously after the reaction begins to reflux; separating the propyl acetate generated in the reaction in an esterification tower, and sending the unreacted raw materials back to the esterification kettle from the bottom of the kettle to continue the reaction; steaming the water and part of the normal propyl alcohol from the tower top; after the cooling, refluxing one part of the steam to the tower top, and sending the other part of the steam to a stratifying device at the tower top; refluxing part of the aqueous phase at the lower layer to the esterification tower through a reflux ratio distributor, and recovering the other part of the aqueous phase; and sending the ester phase at the upper layer to the production purification stage for the further separation to obtain the propyl acetate product. The method of the invention has simple process, high esterification conversion rate, good product selectivity, recyclable catalyst, no device corrosion, environmental protection, simple synthesis method of the selected ionic liquid catalyst, and better solubility of the acid inorganic compound.

Description

technical field [0001] The present invention relates to a kind of processing method of n-propyl acetate, more specifically, it is a kind of processing method that utilizes ionic liquid to be the continuous production of n-propyl acetate as catalyst. Background technique [0002] N-propyl acetate is a colorless, transparent liquid with aromatic odor, flammable and volatile, miscible with various organic solvents such as alcohol, ketone, ether, etc., and has excellent solubility for various synthetic resins. It is an ethyl fiber An effective solvent for many synthetic resins such as cellulose, nitrocellulose, polystyrene, and methacrylate resins. It is often used in organic synthesis process and as a solvent for coatings, printing inks, etc. It is also a commonly used dehydrating agent in industry. [0003] N-propyl acetate is usually prepared by reacting glacial acetic acid and n-propanol under the catalysis of concentrated sulfuric acid. The specific steps are to add glaci...

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Problems solved by technology

[0007] (2) n-propyl acetate has a higher yield in the traditional process, at the cost of a large amount of head fraction returning to the reactor of the esterification tower, because the head fraction contains a high proportion of n-propyl acetate, thereby reducing the The conversion rate of the reaction;

[0008] (3) Since the whole process is operated intermittently, waste acid and neutralized waste liquid are discharged in each operation, and the total waste liquid is relatively large, which increases the operating cost

In 2002, foreign countries reported the method of utilizing ionic liquid to catalyze esterification. The ionic liquid used in this method is complex to synthesize, and needs a large amount of organic solvent, and the conversion rate of esterification is not high. +BF4-catalyzed preparation of esters

However, this method also has the disadvantages of large amount of ionic liquid, cumbersome catalyst post-treatment steps, high energy consumption, etc., and cannot be industrialized.

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