High-efficiency energy-saving preparation method and preparation device of acetylacetone

Abstract

The invention relates to a preparation method of a chemical or medical intermediate, and in particular relates to a high-efficiency energy-saving preparation method and preparation device of acetylacetone. The method sequentially comprises the steps of: adding acetone and introducing ketene simultaneously, proceeding with the reaction through continuously introducing isopropenyl acetate esterification liquid, continuously discharging the isopropenyl acetate esterification liquid to a simple distillation still, continuously distilling off mixed vapor containing the acetone and isopropenyl acetate, enabling the simply distilled mixed gas to enter an acetone recycling tower, carrying out rectification, recycling the acetone, enabling tower bottoms of the acetone recycling tower to enter an isopropenyl acetate rectifying tower, carrying out rectification, enabling the isopropenyl acetate gas from the tower top to enter into a transposition process after passing through a heat exchanger, carry out an isomerization reaction, enabling the produced transposition mixed gas to enter an end product rectifying tower after exchanging heat with the isopropenyl acetate gas, carrying out rectification and obtaining end products of the acetylacetone. The method has the advantages of realizing the continuous production, greatly reducing the energy consumption, reducing the production cost and achieving the effects of energy conservation and emission reduction.

Description

Technical field [0001] The invention relates to a preparation method and a preparation device of chemical or pharmaceutical intermediates, in particular to a preparation method and a preparation device of high-efficiency and energy-saving acetylacetone. Background technique [0002] In the prior art, the preparation process of acetylacetone is as follows figure 1 Shown: A certain concentration of acetic acid is pyrolyzed to obtain ketene, and then an esterified mixture of isopropenyl acetate and acetone is obtained by acetone absorption and esterification reaction, and then the acetone and isopropenyl acetate in the esterified liquid are obtained by batch distillation Esters are separated from high-boiling impurities, and then they are separated by distillation to obtain relatively pure isopropenyl acetate and recovered acetone. Isopropenyl acetate is isomerized to obtain crude acetylacetone transposition liquid, and then the transposition liquid is passed through the refined Dis...

AI Technical Summary

Problems solved by technology

The specific preparation method is to use acetone to absorb the ketene cracked by acetic acid to obtain an esterification solution containing about 70% isopropenyl acetate, which also has a small amount of solids, and then distill isopropenyl acetate, acetone, etc. The boiling point is separated from the high boiling point acetic anhydride and a small amount of solids, and then the isopropenyl acetate and acetone are condensed and collected, and then enter the acetone recovery tower to recover acetone, and then enter the isopropenyl acetate rectification tower to purify the isopropenyl acetate, and then The isopropenyl acetate liquid is gasified and enters the indexing furnace for isomerization to obtain a mixed gas containing about 80% acetylacetone. After cooling and condensing to wait for the indexing liquid, and then rectifying to obtain the finished product of acetylacetone. The process of repeated evaporation, condensation, re-evaporation, and re-condensation has high energy requirements, and consumes a large amount of steam and cooling water, which is not conducive to energy saving, and the liquid material also needs to be transferred multiple times, and the material is corroded during the production of acetylacetone. It is highly resistant, so the requirements for transfer equipment are high, and repeated evaporation and condensation will easily cause loss of materials, and it is easy to cause losses such as running, popping, dripping, and leaking. At the same time, the amount of equipment maintenance is large, which is not conducive to the improvement of system efficiency. Improvement, process continuity is not enough

[0003] CN101514151B (2012-7-18) discloses a process for preparing acetylacetone from isopropenyl acetate. The steps include steaming isopropenyl acetate into gas through a vaporizer, and then connecting the gas to a carrier gas and / or using self-heat exchange Then enter the reformer to convert the reformed gas and cool it down. However, this process is to vaporize the liquid and then transfer it. In this process, the transferred gas needs to be cooled into a liquid, which consumes a lot of energy and costs a lot.

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