CN118878403A - A comprehensive utilization method of mesityl oxide by-product - Google Patents

Abstract

The invention belongs to the technical field of spice production, and particularly discloses a comprehensive utilization method of mesityl oxide byproducts, which comprises the following steps: the method comprises the steps of continuously reacting low-grade mesityl oxide serving as a raw material with thiolated strong-acid cationic resin WX-1 serving as a catalyst in a tubular reactor to prepare mesityl oxide; the low-grade mesityl oxide is derived from byproducts obtained by preparing mesityl oxide, wherein the GC content of mesityl oxide is 20-80%, and the GC content of 4-methyl-4-pentene-2-one is 5-75%. The method has the advantages of simple process, no solvent, no wastewater generation, good reaction activity and high selectivity, and has good industrial application prospect.

Description

A comprehensive utilization method of mesityl oxide by-product

Technical Field

The invention belongs to the technical field of perfume production, relates to the synthesis of mesityl oxide, and particularly relates to a comprehensive utilization method of by-products in the production process of mesityl oxide.

Background Art

Mesityl oxide, also known as 4-methyl-3-penten-2-one, is a colorless, transparent, oily, flammable liquid with a strong mint or honey-like odor. It is a medium-boiling point strong solvent used as a solvent for nitrocellulose and various resins, especially vinyl resins and spray paints. In the production of fragrances, it is mainly used as an important intermediate for products such as isophorone.

The industrial process for producing mesityl oxide is generally a two-step process. Acetone first undergoes an aldol reaction in the presence of an alkaline catalyst to generate diacetone alcohol, which is then dehydrated to generate mesityl oxide.

Chinese patent CN103772175A discloses a method for simultaneously synthesizing mesityl oxide and sec-butyl alcohol, which uses a fixed bed reactor and solid acid as a catalyst. Two reactions occur simultaneously in the reactor. First, two molecules of acetone undergo a condensation reaction to generate mesityl oxide and water; the byproduct water reacts with n-butene to obtain sec-butyl alcohol, and the selectivity of mesityl oxide is 97%. In order to ensure the conversion rate of acetone, the condensation reaction must adopt a higher pressure condition of 3~10MPa, and the equipment requirements are also high.

US Patent No. 5,292,980A, US Patent No. 08,697,924B2 and US Patent No. 2013/0185922A1 disclose the use of a heterogeneous aluminosilicate catalyst at high temperature (>100° C.) to synthesize diacetone alcohol and mesityl oxide using acetone as a raw material.

However, the by-product 4-methyl-4-pentene-2-one is generated in the above-mentioned process of synthesizing mesityl oxide, resulting in a decrease in reaction yield and difficulty in purifying the mesityl oxide finished product.

Summary of the invention

In view of the deficiencies in the prior art, the object of the present invention is to provide a method for comprehensive utilization of mesityl oxide by-product containing 4-methyl-4-pentene-2-one, so as to achieve comprehensive utilization of mesityl oxide by-product and have high industrial application value.

The present invention is achieved through the following technical solutions:

A method for comprehensive utilization of mesityl oxide by-product comprises the following steps:

Low-quality mesityl oxide is used as a raw material and mercapto-strong acidic cationic resin WX-1 is used as a catalyst to continuously react in a tubular reactor to prepare mesityl oxide; the low-quality mesityl oxide is derived from a by-product obtained from the preparation of mesityl oxide, wherein the GC content of mesityl oxide is 20-80%, and the GC content of 4-methyl-4-penten-2-one is 5-75%.

The reaction equation is as follows:

A further improvement of the present invention is:

The tubular reactor consists of a feed pump, a reaction section and a cooling section. The residence time of the material in the tubular reactor is controlled by controlling the flow rate of the feed pump; the reaction section is made of a stainless steel tube with a length of 4m and an inner diameter of 8mm, filled with a cationic resin catalyst (WX-1), and the reaction temperature is controlled by an oil bath; the cooling section is made of a stainless steel tube with a length of 4m and an inner diameter of 8mm; the back pressure valve at the tail end is used to control the reaction pressure; and the liquid at the outlet of the back pressure valve is collected for analysis.

The loading amount of the mercapto-containing strong acidic cationic resin WX-1 is 55-75 g.

The temperature of the continuous reaction is 50-100° C., the residence time of the material in the reactor is 30-120 min, and the reaction pressure is 0.1-0.2 MPa.

The cationic resin catalyst WX-1 contains a sulfonated styrene-divinylbenzene copolymer with an exchange capacity of 2.8 to 5.5 mg equivalents per gram of dry resin, on which 10 to 30% of the sulfonic acid groups are bonded to alkyl mercaptoamines having 1 to 7 carbon atoms through ammonium sulfonate ion bonds. The schematic structure is shown below:

The beneficial effects of the present invention are:

The method uses thiolated strongly acidic cationic resin WX-1 as a catalyst and low-grade mesityl oxide byproduct produced by synthesizing mesityl oxide as a raw material to highly selectively convert the byproduct 4-methyl-4-penten-2-one into the target product mesityl oxide. The method has simple process, does not use solvents, does not generate waste water, has good reaction activity and high selectivity, and has good industrial application prospects.

DETAILED DESCRIPTION

The present invention is described in detail below in conjunction with specific embodiments.

Example 1: Preparation of mercapto-reactive strong acidic cationic resin WX-1

(1) Preparation of white balls: Add 880 g of 1% polyvinyl alcohol aqueous solution as a dispersant, a mixture of NY-200# solvent oil and refined paraffin (melting point 54~62°C) as a porogen, the weight ratio of paraffin to solvent oil is 3~6.1, the amount added is 60 g, 200 g of styrene, 18 g of divinylbenzene, and 2 g of benzoyl peroxide to a 2L glass reactor, and carry out suspension polymerization reaction at 82±2°C for 6 h under stirring, and then react at 90°C for another 6 h. Discharge, wash with water, and dry.

(2) Sulfonation: Extract the white balls with benzene in a Soxhlet extractor until there is no paraffin in the extract. Add 200g of white balls, 100g of ethylene dichloride and 1400g of 98% sulfuric acid to a 2L three-necked flask, stir and react at 70℃ for 2h, then heat to 80℃ and continue to react for 6h. After the reaction is completed, distill off the ethylene dichloride at normal pressure and continue to react at 110~120℃ for 2h. When the temperature drops to room temperature, wash the residual acid with distilled water and ethanol until the effluent is neutral. The sulfonated resin is dried at room temperature for later use.

(3) Thiolation: Prepare a thiolating agent solvent in a weight ratio of dry resin: mercaptoethylamine hydrochloride: hydrochloric acid: water = 1:0.1:0.1:2. Immerse the resin in the above solution at room temperature and let it stand for 36 hours. Then wash it with distilled water and ethanol in sequence until the effluent is neutral. Filter it, dry it at 80°C for 6 hours, and dry it in a vacuum at 72°C for 12 hours to obtain catalyst WX-1.

Embodiment 2: Comprehensive utilization of mesityl oxide by-product

The experiment was carried out in a stainless steel tube reactor with a length of 4m and an inner diameter of 8mm. The catalyst was a self-made strong acid cationic resin WX-1, and its loading amount was 64g. The reaction temperature was 70℃, the residence time of low-grade mesityl oxide (mesityl oxide GC content was 20%, 4-methyl-4-pentene-2-one GC content was 71%) in the reaction section was 90min, and the reaction pressure was 0.15MPa. After the reaction, gas chromatography was used for qualitative and quantitative analysis of the products. After analysis, the reaction liquid at the reactor outlet had a mesityl oxide GC content of 78.5% and a 4-methyl-4-pentene-2-one GC content of 12.1%. The selectivity and yield data are shown in Table 1

Embodiment 3: Comprehensive Utilization of Mesityl Oxide By-product

The experiment was carried out in a stainless steel tube reactor with a length of 4m and an inner diameter of 8mm. The catalyst was a self-made strong acid cationic resin WX-1, and its loading amount was 64g. The reaction temperature was 80℃, the residence time of low-grade mesityl oxide (mesityl oxide GC content was 20%, 4-methyl-4-pentene-2-one GC content was 71%) in the reaction section was 90min, and the reaction pressure was 0.15MPa. After the reaction, gas chromatography was used for qualitative and quantitative analysis of the products. After analysis, the GC content of mesityl oxide in the reaction liquid at the reactor outlet was 87.5%, and the GC content of 4-methyl-4-pentene-2-one was 3.4%. The selectivity and yield data are shown in Table 1

Embodiment 4: Comprehensive Utilization of Mesityl Oxide By-product

The experiment was carried out in a stainless steel tube reactor with a length of 4m and an inner diameter of 8mm. The catalyst was a self-made strong acid cationic resin WX-1, and its loading amount was 64g. The reaction temperature was 90℃, the residence time of low-grade mesityl oxide (mesityl oxide GC content was 20%, 4-methyl-4-pentene-2-one GC content was 71%) in the reaction section was 90min, and the reaction pressure was 0.15MPa. After the reaction, gas chromatography was used for qualitative and quantitative analysis of the products. After analysis, the GC content of mesityl oxide in the reaction liquid at the reactor outlet was 88.6%, and the GC content of 4-methyl-4-pentene-2-one was 2.3%. The selectivity and yield data are shown in Table 1

Example 5: Comprehensive Utilization of Mesityl Oxide By-Product

The synthesis experiment of mesityl oxide was carried out in a stainless steel tube reactor with a length of 4m and an inner diameter of 8mm. The catalyst was a self-made strong acidic cationic resin WX-1, and its loading amount was 64g. The reaction temperature was 80℃, the residence time of low-grade mesityl oxide (mesityl oxide GC content was 77%, 4-methyl-4-pentene-2-one GC content was 16%) in the reaction section was 60min, and the reaction pressure was 0.15MPa. After the reaction, the product was qualitatively and quantitatively analyzed by gas chromatography. After analysis, the GC content of mesityl oxide in the reaction liquid at the reactor outlet was 91.2%, and the GC content of 4-methyl-4-pentene-2-one was 1.8%. The selectivity and yield data are shown in Table 1

Embodiment 6: Comprehensive Utilization of Mesityl Oxide By-product

The synthesis experiment of mesityl oxide was carried out in a stainless steel tube reactor with a length of 4m and an inner diameter of 8mm. The catalyst was a D072 type strong acidic cationic resin with a loading amount of 66g. The reaction temperature was 80°C, the residence time of low-quality mesityl oxide (mesityl oxide GC content of 44%, 4-methyl-4-pentene-2-one GC content of 52%) in the reaction section was 60min, and the reaction pressure was 0.15MPa. After the reaction, gas chromatography was used for qualitative and quantitative analysis of the product. After analysis, the GC content of mesityl oxide in the reaction liquid at the reactor outlet was 92.5%, and the GC content of 4-methyl-4-pentene-2-one was 3.4%. The selectivity and yield data are shown in Table 1

In order to show the reaction characteristics of the catalyst provided by the present invention on the isomerization of low-grade mesityl oxide (mesityl oxide GC content of 44%, 4-methyl-4-penten-2-one GC content of 52%) into mesityl oxide, three other commercially available sulfonic acid group strong acid cationic resin catalysts (D072, NKC-9 and Amberlyst15) were measured in parallel under the same conditions.

Comparative Example 1

The synthesis experiment of mesityl oxide was carried out in a stainless steel tube reactor with a length of 4m and an inner diameter of 8mm. The catalyst was a D072 type strong acidic cationic resin with a loading amount of 66g. The reaction temperature was 80°C, the residence time of low-quality mesityl oxide (mesityl oxide GC content of 44%, 4-methyl-4-pentene-2-one GC content of 52%) in the reaction section was 60min, and the reaction pressure was 0.15MPa. After the reaction, the product was qualitatively and quantitatively analyzed by gas chromatography. After analysis, the GC content of mesityl oxide in the reaction liquid at the reactor outlet was 79.5%, and the GC content of 4-methyl-4-pentene-2-one was 14.9%. The selectivity and yield data are shown in Table 1

Comparative Example 2

The synthesis experiment of mesityl oxide was carried out in a stainless steel tube reactor with a length of 4m and an inner diameter of 8mm. The catalyst was a NKC-9 type strong acidic cationic resin with a loading amount of 70g. The reaction temperature was 80℃, the residence time of low-quality mesityl oxide (mesityl oxide GC content of 44%, 4-methyl-4-pentene-2-one GC content of 52%) in the reaction section was 60min, and the reaction pressure was 0.15MPa. After the reaction, the product was qualitatively and quantitatively analyzed by gas chromatography. After analysis, the GC content of mesityl oxide in the reaction liquid at the reactor outlet was 84.3%, and the GC content of 4-methyl-4-pentene-2-one was 11.0%. The selectivity and yield data are shown in Table 1

Comparative Example 3

The synthesis experiment of mesityl oxide was carried out in a stainless steel tube reactor with a length of 4m and an inner diameter of 8mm. The catalyst was Amberlyst15 type strong acidic cationic resin, and its loading amount was 60g. The reaction temperature was 80℃, the residence time of low-quality mesityl oxide (mesityl oxide GC content was 44%, 4-methyl-4-pentene-2-one GC content was 52%) in the reaction section was 60min, and the reaction pressure was 0.15MPa. After the reaction, the product was qualitatively and quantitatively analyzed by gas chromatography. After analysis, the GC content of mesityl oxide in the reaction liquid at the reactor outlet was 82.3%, and the GC content of 4-methyl-4-pentene-2-one was 12.5%. The selectivity and yield data are shown in Table 1

Table 1 Reaction results of Examples 2-9

Reaction parameters Example 2 Example 3 Example 4 Example 5 Example 6 Comparative Example 1 Comparative Example 2 Comparative Example 3 Catalyst type WX-1 WX-1 WX-1 WX-1 WX-1 D072 NKC-9 Amberlyst15 Reaction temperature/℃ 70 80 90 80 80 80 80 80 Residence time/min 90 90 90 60 60 60 60 60 Reaction pressure/Mpa 0.15 0.15 0.15 0.15 0.15 0.15 0.15 0.15 Yield/% 82.4 95.1 96.6 88.7 93.2 68.3 77.5 73.7 Selectivity/% 96.7 96.9 96.4 97.0 96.6 90.5 93.6 91.4

The above embodiments are only for illustrating the technical concept and features of the present invention, and their purpose is to enable people familiar with the technology to understand the content of the present invention and implement it accordingly, and they cannot be used to limit the protection scope of the present invention. Any equivalent transformation or modification made according to the spirit of the present invention should be included in the protection scope of the present invention.

Claims (5)

1. The comprehensive utilization method of the mesityl oxide byproduct is characterized by comprising the following steps: the method comprises the steps of continuously reacting low-grade mesityl oxide serving as a raw material with thiolated strong-acid cationic resin WX-1 serving as a catalyst in a tubular reactor to prepare mesityl oxide; the low-grade mesityl oxide is derived from byproducts obtained by preparing mesityl oxide, wherein the GC content of mesityl oxide is 20-80%, and the GC content of 4-methyl-4-pentene-2-one is 5-75%.

2. The method for the comprehensive utilization of mesityl oxide by-product according to claim 1, which is characterized in that: the tubular reactor consists of a feed pump, a reaction section and a cooling section, wherein the reaction section is made of stainless steel pipes with the length of 4m and the inner diameter of 8 mm.

3. The method for the comprehensive utilization of mesityl oxide by-product according to claim 1, which is characterized in that: the loading of the sulfhydrylation strong acid cationic resin WX-1 is 55-75 g.

4. The method for the comprehensive utilization of mesityl oxide by-product according to claim 1, which is characterized in that: the temperature of the continuous reaction is 50-100 ℃, the residence time of the materials in the reactor is 30-120 min, and the reaction pressure is 0.1-0.2 MPa.

5. The method for the comprehensive utilization of mesityl oxide by-product according to claim 1, which is characterized in that: the cationic resin catalyst WX-1 contains sulfonated styrene-divinylbenzene copolymer, the exchange capacity of the sulfonated styrene-divinylbenzene copolymer is 2.8-5.5 milliequivalents/gram of dry resin, and 10-30% of sulfonic acid groups on the cationic resin catalyst are bonded with alkyl sulfhydryl amine with 1-7 carbon atoms through ammonium sulfonate ion bonding.