Synthesis method of pinacolone

Abstract

The present invention relates to a pinacolone synthesis method, and belongs to the technical field of organic synthesis, the method comprises the following steps: Step 1, isoamylene is adopted as a raw material, and is subjected to an addition reaction with methanol in the presence of an acid catalyst to obtain a methyl ether intermediate, the acid catalyst is sulfuric acid, the mass ratio of isoamylene to methanol is 1: 2-1: 3, and the methyl ether intermediate is obtained; the addition reaction temperature is controlled to be 80-100 DEG C; and Step 2, after the reaction is finished, hydrolyzing the methyl ether intermediate to obtain pinacolone. The synthesis method is green and environment-friendly, a large amount of strong acid and excessive formaldehyde are avoided, so that a large amount of tar and a large amount of waste acid are not generated, and the amount of three wastes is greatly reduced, and compared with other traditional synthesis methods in which pivalic acid or 2-chloro-2-methylbutane is used as a raw material, the synthesis method disclosed by the invention has the advantages that isoamylene is used as a raw material; according to the present invention, the raw materials are cheap and easily available, the process is simple, the amount of the three wastes is substantially reduced, and the method has high industrial production value.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and in particular to a method for synthesizing pinacolone. Background Technology

[0002] Pinarone is an important fine chemical intermediate, especially as a raw material for the synthesis of the fungicide tebuconazole. The market demand for pinarone is increasing. Its molecular structure is shown below: .

[0003] Existing pinacolone synthesis processes are complex, involve numerous reaction steps, generate large amounts of waste, have high raw material costs, and face difficulties in obtaining raw materials or intermediates, making industrial-scale production challenging. For example, the synthesis method reported in patent CN101289376 requires pentanoic acid, a raw material that is difficult to obtain, and requires a reaction temperature of 400℃, making industrial-scale production difficult. Another example is the synthesis method reported in CN106365964, which uses isopentenene to react with hydrochloric acid to obtain chloropentane, followed by reaction with formaldehyde and rearrangement to obtain pinacolone. This process involves long reaction steps, generates large amounts of waste acid and waste tar, and produces a large amount of waste. Yet another example is the method reported in CN105348055, which uses 2-chloro-2-methylbutane as a raw material. This raw material is not readily available on the market, resulting in high production costs.

[0004] Therefore, the demand for a simple, efficient, low-cost, low-waste, and suitable method for industrial-scale production of pinacolone synthesis is a key focus of research in this field. Summary of the Invention

[0005] This invention provides a method for synthesizing pinacolone, which solves the problems of lengthy steps and the use of expensive or hard-to-find raw materials in traditional synthesis routes. By using common isopentenylene and methanol as starting materials, this invention provides a more direct and economical synthesis route, reducing raw material costs. It also solves the problem that traditional synthesis routes use large amounts of strong acids and excessive formaldehyde, which will generate a large amount of tar and waste acid, effectively reducing the amount of waste and making it more green and environmentally friendly.

[0006] The present invention provides the following solution to the above-mentioned technical problems: a method for synthesizing pinacolone, the method comprising the following steps:

[0007] Step 1: Using isopentenene as a raw material, it reacts with methanol under acidic catalyst conditions to obtain a dimethyl ether intermediate. The acidic catalyst is sulfuric acid, the mass ratio of isopentenene to methanol is 1:2 - 1:3, the addition reaction temperature is controlled at 80-100℃, and the addition holding time is 5-6 hours.

[0008] Step 2: After the reaction is complete, the dimethyl ether intermediate is hydrolyzed to obtain pinacolone. The hydrolysis reaction temperature is controlled at 50-64℃, and the hydrolysis holding time is 3-5h.

[0009] Based on the above technical solution, the present invention can be further improved as follows.

[0010] Furthermore, the sulfuric acid in the acidic catalyst can be replaced with any one or more of the following: hydrochloric acid, phosphoric acid, nitric acid, acidic resin, aluminum trichloride, and ferric chloride. By providing a variety of catalyst options, the most suitable catalyst can be selected according to actual production conditions (such as raw material availability, cost, or equipment compatibility), thereby optimizing the production process.

[0011] Furthermore, the amount of sulfuric acid used is 1%-5% of the mass of isopentene. This limited range of dosage ensures that there is sufficient catalyst to effectively promote the addition reaction, while avoiding side reactions (such as excessive hydrolysis or decomposition) caused by excessive dosage, thereby improving the purity and yield of pinacolone.

[0012] The beneficial effects of this invention are: this invention provides a method for synthesizing pinacolone, which has the following advantages;

[0013] 1. Green and environmentally friendly, avoiding the use of large amounts of strong acids and excessive formaldehyde, thus avoiding the generation of large amounts of tar and waste acid, thereby greatly reducing the amount of waste.

[0014] 2. Compared with other traditional synthesis methods that use pentyl acid or 2-chloro-2-methylbutane as raw materials, the synthesis method of the present invention uses isopentenene as raw material, which is directly added to methanol to obtain a methyl ether intermediate, and then hydrolyzed to obtain pinacolone. The raw materials are cheap and readily available, and the process is simple, with a significant reduction in the amount of waste, and has high industrial production value.

[0015] 3. Using isopentenene and methanol as raw materials, which are widely available and relatively low in cost, is conducive to large-scale industrial production and has good economic benefits;

[0016] 4. Optimized reaction conditions ensure that the reaction proceeds at a relatively fast rate. By precisely controlling the amount of catalyst and the holding time, the occurrence of side reactions can be effectively suppressed, thereby improving the yield and purity of pinacolone and reducing the burden of subsequent separation and purification.

[0017] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings. Specific embodiments of the present invention are given in detail below with reference to the accompanying drawings. Attached Figure Description

[0018] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0019] Figure 1 This is a synthetic process route diagram of a method for synthesizing pinacolone according to an embodiment of the present invention. Detailed Implementation

[0020] The following is in conjunction with the appendix Figure 1 The principles and features of the present invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. The invention is described more specifically in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the invention will become clearer from the following description. It should be noted that the drawings are in a very simplified form and use non-precise proportions, and are only used to facilitate and clarify the illustration of the embodiments of the invention.

[0021] The principles and features of the present invention are described below. The examples given are for illustrative purposes only and are not intended to limit the scope of the invention. The invention is described more specifically by way of example in the following paragraphs. The advantages and features of the invention will become clearer from the following description.

[0022] Example 1:

[0023] Step 1: In a 1L pressure vessel, add 100g of isopentene, 300g of methanol, and 1g of sulfuric acid. Seal the pressure vessel, heat to 80℃, and maintain the temperature for 5-6 hours.

[0024] Step 2: After the reaction is complete, add 100g of water to the reaction solution and keep it at 60-64 degrees Celsius for 5 hours for hydrolysis. After concentration, separate the aqueous phase to obtain 131.4g of pinacolone, with a yield of 92%.

[0025] Example 2:

[0026] Step 1: In a 1L pressure vessel, add 100g of isopentene, 300g of methanol, and 5g of sulfuric acid. Seal the pressure vessel, heat to 100℃, and maintain the temperature for 5-6 hours.

[0027] Step 2: After the reaction is complete, add 100g of water to the reaction solution and keep it at 60-64 degrees Celsius for 5 hours for hydrolysis. After concentration, separate the aqueous phase to obtain 132.9g of pinacolone, with a yield of 93%.

[0028] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A process for the synthesis of frentizonc, characterized in that, The synthesis method comprises the following steps: Step 1, isopentene is used as raw material, and addition reaction is carried out with methanol under the condition of an acidic catalyst to obtain a methyl ether intermediate, the acidic catalyst is selected from sulfuric acid, the mass ratio of isopentene to methanol is 1:2-1:3, the addition reaction temperature is controlled to be 80-100 DEG C, the addition heat preservation time is 5-6 h, and the amount of sulfuric acid is 1%-5% of the mass of isopentene; Step 2, after the reaction is completed, the methyl ether intermediate is hydrolyzed to obtain pinacolone, the hydrolysis reaction temperature is controlled to be 50-64 DEG C, and the hydrolysis heat preservation time is 3-5 h.

2. The process for the synthesis of febantel according to claim 1, characterized in that, In step 1, the sulfuric acid of the acidic catalyst can be replaced by one or more of the following: hydrochloric acid, phosphoric acid, nitric acid, acidic resin, aluminum trichloride and ferric trichloride.

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