Method for preparing cyclopropyl methyl ketone

Abstract

The invention relates to a method for preparing cyclopropyl methyl ketone, and belongs to the field of organic synthesis. The preparing method includes the following steps that metal halide and an inert solvent are added into a fixed bed reactor, the fixed bed reactor is heated to 185-195 DEG C, and then alpha-acetyl-gamma-butyrolactone is continuously added into the fixed bed reactor, and is subjected to a cleavage reaction; after the reaction is saturated, the alpha-acetyl-gamma-butyrolactone stops to be added, reaction distillation continues to be carried out till no product is distilled out, and a cyclopropyl-methyl-ketone crude product is obtained; the fixed bed reactor is connected with a rectifying tower, the prepared cyclopropyl-methyl-ketone crude product is transferred into the rectifying tower to be subjected to high tower dividing and then subjected to normal pressure rectification, the reflux ratio is adjusted, impurities are separated, and the high-purity cyclopropyl methyl ketone is obtained through distilling. The method is low in production cost, high in production efficiency, product yield and purity, small in by-product number, wastewater amount, waste material number and environment pollution and more suitable for industrial production.

Description

technical field [0001] The invention relates to the field of organic synthesis, in particular to a preparation method of cyclopropyl methyl ketone. Background technique [0002] Cyclopropyl methyl ketone is a yellow or slightly yellow transparent liquid, which has certain solubility in water and can be miscible with alcohol ether. Cyclopropylmethyl ketone is an important intermediate for the synthesis of cyclopropyne, and cyclopropyne is not only an important intermediate for anti-AIDS Efluviren and Ilremin, but also an important intermediate for the fungicides cyprodinil and cyproconazole. Important raw materials, widely used in the synthesis of medicines and pesticides. [0003] In the prior art, the preparation method of cyclopropyl methyl ketone mainly contains following several kinds: [0004] 1. Prepare cyclopropyl methyl ketone (50% yield) by reacting methyl vinyl ketone and diiodomethane in the presence of octacopper couple, or prepare by reacting acetyl chloride a...

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Problems solved by technology

However, these two methods have disadvantages such as special raw materials and low yields.

[0005] 2. α-acetyl-γ-butyrolactone is halogenated in aqueous medium to obtain 5-halogenated-2-pentanone, and 5-halogenated-2-pentanone undergoes dehydrohalogenation and cyclization reaction under alkaline conditions to form ring Propyl methyl ketone, after the reaction is complete, carry out distillation, layering, extraction, drying, and distillation to obtain cyclopropyl methyl ketone, but this method will produce a large amount of waste acid water, waste alkali water, and solid waste residue, and it will corrode the equipment more serious

[0006] Another example is U.S. Patent (publication No. US5254739) disclosing a method for the continuous production of cyclopropyl methyl ketone using α-acetyl-γ-butyrolactone. In the presence of an inert solvent and an excessive halide catalyst, continuously add α - Acetyl-γ-butyrolactone, and a distillation tower is connected to the reactor, and the product cyclopropyl methyl ketone is continuously distilled to remove the product, thereby improving the reaction efficiency, conversion rate and yield. This method has high reaction efficiency and few by-products , the catalyst can be recycled, and it can be produced on a large scale to realize industrialization, but the amount of catalyst and solvent used in the reaction process is too large, and the halides correspond to acetylbutyrolactone in an excess of 1 to 100 molar equivalents, and the halides are in the solvent. The volume concentration of the halide catalyst is 1 to 40%. The halide catalyst needs to undergo a series of treatments to extract the pure catalyst during repeated use. It is necessary to distill off the mixed solvent first, add water, and extract to remove the organic residue. In the halide Then add the solvent to the aqueous solution, distill off the water, and then add α-acetyl-γ-butyrolactone to start the reaction again. However, a solvent with a high boiling point (about 200° C.) is selected, so the step of distilling off the solvent needs a lot of energy. Because the boiling point of water is not low, the operation of distilling water from the solvent is also quite energy-consuming. It is applied to industrial production. Undoubtedly, a lot of cost has been added. The organic residues removed by extraction and the distilled water become waste water and waste liquid because they contain other chemical substances that cannot be removed. The original article does not mention how to treat this part of waste water and waste liquid, and the direct discharge increases. Environmental pollution, further decontamination treatment will be cumbersome and costly

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