Preparation method of 2-pentylcyclopentyl-2-ketene

Abstract

The invention belongs to the technical field of organic matter preparation, and particularly relates to a preparation method of 2-pentylcyclopentyl-2-ketene. According to the method, methanol is used as a solvent, sulfonic acid type resin doped with lewis acid is used as a catalyst to catalyze the isomerization reaction of 2-pentylidene cyclopentanone, the catalyst and the methanol solvent can jointly promote the isomerization reaction of 2-pentylidene cyclopentanone, and the catalytic efficiency is high, so that the reaction yield is remarkably increased, and the catalyst cost is reduced; in addition, a fixed bed reactor continuous production mode is adopted, waste salt is prevented from being generated when the acid catalyst is quenched by processes such as HCl / HBr / p-toluenesulfonic acid, and methanol is used as a solvent, so that the byproduct dimethyl ether is simply separated from water and the solvent methanol. In addition, when the sulfonic acid type resin doped with the lewis acid is used for catalyzing the isomerization reaction of 2-pentylidene cyclopentanone, the stability is high, and the service life is long.

Description

Technical Field

[0001] The invention belongs to the technical field of organic matter preparation, and particularly relates to a method for preparing 2-pentylcyclopent-2-enone. Background Art

[0002] Methyl dihydrojasmonate (MDJ) is a synthetic jasmone-like compound with a rich jasmine and fruity aroma. It is widely used in detergent additives and cosmetics, and has a large market share. Its industrial synthesis method basically uses n-valeraldehyde and cyclopentanone as starting materials, and is prepared through aldol condensation, dehydration, isomerization, Michael addition, and hydrolysis and decarboxylation. The isomerized product 2-pentylcyclopent-2-enone is the key intermediate. Its main synthesis methods are as follows:

[0003] (1) One-pot synthesis using n-valeraldehyde as raw material: 2-pentylcyclopent-2-enone is directly synthesized in a one-pot process using hydrotalcite as a catalyst from n-valeraldehyde and cyclopentanone. The conversion rate of n-valeraldehyde can reach 93%, and the product selectivity can reach 90%. However, the content of by-products from the aldol condensation of the aldehyde itself and the further aldol condensation of 2-pentylcyclopent-2-enone with a molecule of n-valeraldehyde is high.

[0004] (2) One-pot synthesis of 2-(1-hydroxypentyl)-cyclopentane-1-one as raw material: Using n-valeraldehyde and cyclopentanone as raw materials, the undehydrated hydroxy intermediate compound 2-(1-hydroxypentyl)-cyclopentane-1-one is first synthesized at low temperature, and then the undehydrated hydroxy intermediate compound is subjected to a two-step dehydration and isomerization reaction in the presence of H3PO4 / C, Pd / C, N2 / H2 mixed gas flow and sulfur powder in one pot to obtain 2-pentylcyclopent-2-enone, and the product selectivity can reach 95%; however, the amount of precious metal Pd catalyst used is large, and the cost is high;

[0005] (3) Synthesis by isomerization reaction using 2-pentylenecyclopentanone as raw material:

[0006] ① Isomerization reaction catalyzed by metal catalyst / H2 system

[0007] 2-pentylcyclopentanone is reacted in 5% Pd / C, H2 / N2=1 / 7 (volume ratio) at 150°C for 9-12 hours to obtain 2-pentylcyclopent-2-enone with a yield of up to 89%. However, the yield is low and the cost of the noble metal catalyst is high.

[0008] ② Isomerization reaction catalyzed by acid / alcohol system

[0009] This type of catalytic isomerization reaction is usually carried out in HBr, HCl, p-toluenesulfonic acid or solid acid and alcohol solvents. The reaction conditions usually require reflux, which has disadvantages such as large catalyst volatilization loss, many by-products such as hydrogen halide and alcohol, alcohol and alcohol, and water generated in the system, which makes the post-processing alcohol / ether / water separation difficult or the separation cost is high.

[0010] The disadvantages of the existing technology are: the three-step one-pot synthesis method of aldol condensation, dehydration and isomerization with n-valeraldehyde as raw material is not yet mature, the product yield is low, there are many by-products in the aldehyde self-condensation and further condensation of the product, and the research on catalyst recycling is insufficient, which limits the industrialization process of this process; the two-step one-pot synthesis method of dehydration and isomerization with 2-(1-hydroxypentyl)-cyclopentane-1-one as raw material has great industrialization prospects, but it requires the use of precious metal catalysts, which is costly; the synthesis of 2-pentylcyclopent-2-enone with 2-pentylidenecyclopentanone as raw material through a one-step isomerization reaction is currently relatively Although it is a relatively mature and industrially adopted technology, the metal catalyst / H2 system catalyzed isomerization reaction still has the problem of high catalyst cost. In the acid / alcohol system catalyzed isomerization reaction, the acid is generally HCl, HBr, p-toluenesulfonic acid or solid acid, and the alcohol is n-butanol. It has the advantages of simple operation and cheap raw and auxiliary materials. However, it also has the disadvantages of low reaction yield, high cost of post-treatment separation of alcohol and by-product ether and water, low output per unit volume of reaction equipment due to large amount of solvent, and the need to quench the catalyst acid with alkaline solution after the reaction stops, resulting in large amount of catalyst and large amount of waste salt. Summary of the Invention

[0011] The object of the present invention is to provide a method for preparing 2-pentylcyclopent-2-enone. The preparation method provided by the present invention has high yield, low cost for separation of solvent, by-product ether and water, low solvent usage, and no waste salt is generated.

[0012] In order to achieve the above object, the present invention provides the following technical solutions:

[0013] The present invention provides a method for preparing 2-pentylcyclopent-2-enone, comprising the following steps:

[0014] 2-pentylidenecyclopentanone is continuously isomerized in a fixed-bed reactor using a sulfonic acid resin doped with a Lewis acid as a catalyst and methanol as a solvent to obtain an isomerization reaction liquid.

[0015] The isomerization reaction liquid is subjected to gas-liquid separation, and the obtained liquid phase is sequentially subjected to impurity removal and purification to obtain 2-pentylcyclopent-2-enone.

[0016] Preferably, the preparation of the Lewis acid-doped sulfonic acid resin comprises the following steps: subjecting the sulfonic acid resin to ion exchange and drying to obtain an H-type resin; mixing the H-type resin with a lower alcohol solution containing a Lewis acid, and heat-treating the resulting mixed liquid to obtain the Lewis acid-doped sulfonic acid resin.

[0017] Preferably, the sulfonic acid resin includes one or more of D001-CC, NKC-9, D72, D61, CT175, SK104, SK106, SK116, PK208, PK212, PK216, PK220, PK228, HPK25, K2431, K2621, K2641, X284 and CSP-2.

[0018] Preferably, the Lewis acid comprises one or more of aluminum chloride, zinc chloride, zinc bromide, zirconium chloride, ferric chloride, ferric bromide, niobium pentachloride, tin tetrachloride and nickel chloride.

[0019] Preferably, the mass ratio of the Lewis acid to the sulfonic acid resin is 0.05:1 to 0.25:1.

[0020] Preferably, the heat treatment is carried out under stirring conditions; the heat treatment is heating to boiling; and the lower alcohol is methanol or ethanol.

[0021] Preferably, the mass ratio of the 2-pentylenecyclopentanone to methanol is 1:1 to 1:6; the mass ratio of the 2-pentylenecyclopentanone to the catalyst is 100:5 to 100:80.

[0022] Preferably, the temperature of the continuous isomerization reaction is 110° C. to 160° C., the pressure is 0.9 MPa to 4.5 MPa, and the reaction time is 0.5 h to 12 h.

[0023] Preferably, the continuous isomerization reaction is carried out by passing a mixed solution of 2-pentylenecyclopentanone and methanol into a fixed bed reactor fixed with a catalyst to carry out the continuous isomerization reaction.

[0024] Preferably, the flow rate of the mixed solution of 2-pentylenecyclopentanone and methanol is 50 to 200 g / h.

[0025] The present invention provides a method for preparing 2-pentylcyclopent-2-enone, comprising the following steps: performing a continuous isomerization reaction on 2-pentylcyclopentanone in a fixed-bed reactor using a sulfonic acid resin doped with a Lewis acid as a catalyst and methanol as a solvent to obtain an isomerization reaction liquid; subjecting the isomerization reaction liquid to gas-liquid separation, and sequentially removing impurities and purifying the resulting liquid phase to obtain 2-pentylcyclopent-2-enone. The present invention uses methanol as a solvent and the sulfonic acid resin doped with a Lewis acid as a catalyst to catalyze the isomerization reaction of 2-pentylcyclopentanone. The catalyst and the methanol solvent can jointly promote the isomerization reaction of 2-pentylcyclopentanone, resulting in high catalytic efficiency, thereby significantly improving the reaction yield and reducing catalyst costs. Furthermore, the present invention utilizes a fixed-bed reactor for continuous production, avoiding the generation of waste salts when quenching the acidic catalyst using processes such as HCl / HBr / p-toluenesulfonic acid. The use of methanol as a solvent simplifies the separation of the byproduct dimethyl ether from water and the methanol solvent. In addition, when the Lewis acid-doped sulfonic acid resin provided by the present invention catalyzes the isomerization reaction of 2-pentylenecyclopentanone, it has high stability and long service life.

[0026] In summary, the preparation method provided by the present invention has the advantages of cheap and readily available catalyst, high stability, high product yield, simple operation, suitability for industrial production, simple separation of by-products (simple post-processing process) and no waste salt generation (more environmentally friendly).

[0027] Furthermore, the present invention has the advantage of requiring less solvent. DETAILED DESCRIPTION

[0028] The present invention provides a method for preparing 2-pentylcyclopent-2-enone, comprising the following steps:

[0029] 2-pentylidenecyclopentanone is continuously isomerized in a fixed bed reactor using a sulfonic acid resin doped with a Lewis acid as a catalyst and methanol as a solvent to obtain an isomerization reaction liquid.

[0030] The isomerization reaction liquid is subjected to gas-liquid separation, and the obtained liquid phase is sequentially subjected to impurity removal and purification to obtain 2-pentylcyclopent-2-enone.

[0031] The invention uses sulfonic acid resin doped with Lewis acid as a catalyst and methanol as a solvent to carry out a continuous isomerization reaction on 2-pentylidenecyclopentanone in a fixed bed reactor to obtain an isomerization reaction liquid.

[0032] As an embodiment of the present invention, the preparation of the sulfonic acid resin doped with Lewis acid includes the following steps: ion exchange and drying the sulfonic acid resin to obtain an H-type resin; mixing the H-type resin with a lower alcohol solution containing a Lewis acid, and heat treating the resulting mixed liquid to obtain the sulfonic acid resin doped with Lewis acid.

[0033] As an embodiment of the present invention, the ion exchange is preferably performed by placing the sulfonic acid resin into a column and eluting it with an inorganic acid aqueous solution to convert it into the H-type.

[0034] As an embodiment of the present invention, the inorganic acid includes hydrochloric acid or sulfuric acid; the concentration of the inorganic acid aqueous solution can be 6 M. As an embodiment of the present invention, the Lewis acid can include one or more of aluminum chloride, zinc chloride, zinc bromide, zirconium chloride, ferric chloride, ferric bromide, niobium pentachloride, tin tetrachloride, and nickel chloride, and can specifically include zinc chloride and / or zirconium chloride. As an embodiment of the present invention, the sulfonic acid resin can include one or more of D001-CC, NKC-9, D72, D61, CT175, SK104, SK106, SK116, PK208, PK212, PK216, PK220, PK228, HPK25, K2431, K2621, K2641, X284, and CSP-2, and can specifically include one or more of D61, D72, PK220, and PK228. As one embodiment of the present invention, the mass ratio of the Lewis acid to the sulfonic acid resin can be 0.05:1 to 0.25:1, specifically 0.08:1 to 0.15:1. As one embodiment of the present invention, the mass concentration of the lower alcohol solution containing the Lewis acid can be 1 to 15%; the lower alcohol can be methanol or ethanol.

[0035] In one embodiment of the present invention, after ion exchange, the resin is further washed and dried. The washing may be performed with deionized water until the pH of the washing solution approaches that of deionized water, i.e., the pH is close to 7. In another embodiment of the present invention, the drying may be performed in a vacuum drying oven. The drying temperature may be 80° C., and the drying time may be 4 to 12 hours.

[0036] As an embodiment of the present invention, the heat treatment may heat the mixed liquid to boiling; the heat treatment is carried out under stirring conditions; the heat treatment time may be 2 to 10 hours, specifically 3 to 5 hours. As an embodiment of the present invention, after the heat treatment, the mixed material after the heat treatment is cooled to room temperature, filtered, and the solid phase obtained is washed, impurity-removed, and dried in sequence to obtain the catalyst. As an embodiment of the present invention, the washing includes ethanol washing and deionized water washing in sequence; the drying temperature may be 80°C and the drying time may be 4 to 12 hours.

[0037] As an embodiment of the present invention, the continuous isomerization reaction is preferably carried out by passing a mixed solution of 2-pentylenecyclopentanone and methanol into a fixed bed reactor fixed with a catalyst to carry out the continuous isomerization reaction.

[0038] As one embodiment of the present invention, the mass ratio of the 2-pentylenecyclopentanone to methanol can be 1:1 to 1:6, specifically 1:2 to 1:4; the mass ratio of the 2-pentylenecyclopentanone to the catalyst can be 100:5 to 100:80, specifically 100:15 to 100:35. As one embodiment of the present invention, the mixture of 2-pentylenecyclopentanone and methanol is preferably pumped into the fixed bed reactor via a liquid phase pump; the flow rate of the mixture of 2-pentylenecyclopentanone and methanol can be 50 to 150 g / h, specifically 100 g / h.

[0039] As an embodiment of the present invention, the temperature of the isomerization reaction can be 110°C to 160°C, specifically 130°C to 150°C; the pressure can be 0.9MPa to 4.5MPa, specifically 1.6MPa to 2.2MPa; and the reaction time can be 0.5h to 12h, specifically 2h to 6h.

[0040] After obtaining the isomerization reaction liquid, the present invention performs gas-liquid separation on the isomerization reaction liquid, and the obtained liquid phase is sequentially subjected to impurity removal and purification to obtain 2-pentylcyclopent-2-enone.

[0041] As an embodiment of the present invention, before the gas-liquid separation, the isomerization reaction liquid is cooled from the tail end of the fixed bed reactor and then continuously discharged; the cooling temperature can be ≤54°C, specifically 20°C to 45°C.

[0042] As an embodiment of the present invention, the impurity removal is to remove methanol and by-product water; the impurity removal can be performed by atmospheric distillation; and the purification method can be reduced pressure distillation.

[0043] As an embodiment of the present invention, the continuous isomerization reaction preferably further produces dimethyl ether as a by-product; after the dimethyl ether is separated from the gas and liquid, it is dried and then absorbed by methanol.

[0044] In the present invention, the by-product dimethyl ether can be used to co-produce dimethyl sulfate, thereby further improving the utilization of the by-product and reducing the cost.

[0045] In order to further illustrate the present invention, the scheme of the present invention is described in detail below with reference to the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0046] Example 1

[0047] Preparation of catalyst: 50 g of D72-Na sulfonic acid resin (50% water content) was placed in a glass column and washed with 70 mL of 6M hydrochloric acid to convert it to the H-type. It was then rinsed with 250 mL of deionized water until the pH of the wash water was close to that of deionized water and dried in a vacuum drying oven at 80°C overnight. Using a three-necked flask as a reactor, the H-type resin was placed in a flask, 120.00 g of an ethanol solution containing 5.50 g of zinc chloride was added (the mass ratio of zinc chloride to D72-Na sulfonic acid resin was 0.11:1, and the mass concentration of ethanol in the ethanol solution was 10%), and an electric stirrer was started. The mixture was heated to boiling and allowed to react for 4 h. After naturally cooling to room temperature, it was filtered and the product was washed with 30 mL of ethanol and 30 mL of deionized water in sequence to remove excess impurities. The product was then dried in a vacuum drying oven at 80°C for 12 h to obtain 29.31 g of a milky white Lewis acid-doped resin catalyst, designated Cat-1.

[0048] Continuous isomerization reaction: 25.00 g of Cat-1 prepared above was charged into a fixed-bed reactor, 100.00 g of the compound 2-pentylcyclopentanone with a content of 97.5% was pre-mixed with 300.00 g of methanol, and then continuously pumped into the fixed-bed reactor at a flow rate of 100 g / h using a liquid phase pump. The reaction temperature was controlled at 140° C. and the reaction pressure was controlled at 1.9 MPa, and the reaction was allowed to proceed in the fixed-bed reactor for 4 hours. After the reaction was completed, the fixed bed was cooled to 45° C. at the tail end and the material was continuously discharged. The by-product dimethyl ether was subjected to gas-liquid separation and drying and then absorbed by methanol. The reaction liquid after gas-liquid separation weighed 318.80 g. Methanol and by-product water were removed by atmospheric distillation, and the product was then distilled off under reduced pressure using a water ring pump to obtain 97.7 g of 2-pentylcyclopent-2-enone product with a purity of 96.9% and a yield of 97.1%.

[0049] The differences between the conditions of Examples 2 to 14 and Example 1 are shown in Table 1.

[0050] Table 1 Differences in conditions between Examples 2-14 and Example 1

[0051]

[0052] Comparative Example 1

[0053] 25.00 g of D72-Na sulfonic acid resin was charged into a fixed-bed reactor, 100.00 g of a compound 2-pentylcyclopentanone with a content of 97.5% was pre-mixed with 300.00 g of methanol, and then continuously pumped into the fixed-bed reactor at a flow rate of 100 g / h using a liquid phase pump. The reaction temperature was controlled to 140° C. and the reaction pressure was controlled to a maximum of 1.9 MPa, and the reaction was allowed to proceed in the fixed-bed reactor for 8 hours. After the reaction was completed, the fixed bed was cooled to 45° C. at the tail end and the material was continuously discharged. The by-product dimethyl ether was subjected to gas-liquid separation and drying and then absorbed by methanol. The reaction liquid after gas-liquid separation weighed 316.99 g. Methanol and by-product water were removed by atmospheric distillation, and the product was then distilled off under reduced pressure using a water ring pump to obtain 95.41 g of 2-pentylcyclopent-2-enone product with a purity of 93.5% and a yield of 91.5%.

[0054] Comparative Example 2

[0055] The preparation of the catalyst is the same as in Example 1;

[0056] 25.00 g of the Cat-1 prepared above was charged into a fixed-bed reactor, and 100.00 g of the compound 2-pentylcyclopentanone with a content of 97.5% and 300.00 g of n-butanol were premixed and continuously pumped into the fixed-bed reactor at a flow rate of 100 g / h using a liquid phase pump. The reaction temperature was controlled to 140° C. and the reaction pressure was kept at a maximum of 1.9 MPa in the fixed-bed reactor for 6.5 h. After the reaction was completed, the fixed bed was cooled to 45° C. and the material was continuously discharged from the tail end. The reaction liquid weighed 399.18 g. Methanol and by-product water were removed by atmospheric distillation, and the product was then distilled off under reduced pressure using a water ring pump to obtain 96.25 g of 2-pentylcyclopent-2-enone product with a purity of 93.8% and a yield of 92.6%.

[0057] Comparative Example 3

[0058] 25.00 g of D72-Na sulfonic acid resin was charged into a fixed-bed reactor. 100.00 g of a compound 2-pentylcyclopentanone with a content of 97.5% and 300.00 g of n-butanol were premixed and continuously pumped into the fixed-bed reactor at a flow rate of 100 g / h using a liquid phase pump. The reaction temperature was controlled at 140° C. and the reaction pressure was controlled to be a maximum of 1.9 MPa. The reaction was allowed to proceed in the fixed-bed reactor for 12 hours. After the reaction was completed, the fixed bed was cooled to 45° C. at the tail end and the material was continuously discharged. The reaction liquid weighed 398.97 g. Methanol and by-product water were removed by atmospheric distillation, and the product was then distilled off under reduced pressure using a water ring pump to obtain 90.76 g of 2-pentylcyclopent-2-enone product with a purity of 91.1% and a yield of 84.8%.

[0059] Although the above embodiment provides a detailed description of the present invention, it is only a part of the embodiments of the present invention, not all of the embodiments. Other embodiments can be obtained based on this embodiment without creativity, and these embodiments all fall within the scope of protection of the present invention.

Claims

1. A method for preparing 2-pentylcyclopent-2-enone, comprising the following steps: 2-pentylidenecyclopentanone is continuously isomerized in a fixed-bed reactor using a sulfonic acid resin doped with a Lewis acid as a catalyst and methanol as a solvent to obtain an isomerization reaction liquid. The isomerization reaction liquid is subjected to gas-liquid separation, and the obtained liquid phase is sequentially subjected to impurity removal and purification to obtain 2-pentylcyclopent-2-enone.

2. The preparation method according to claim 1, wherein The preparation of the Lewis acid-doped sulfonic acid resin comprises the following steps: subjecting the sulfonic acid resin to ion exchange and drying to obtain an H-type resin; mixing the H-type resin with a lower alcohol solution containing a Lewis acid, and heat-treating the resulting mixed liquid to obtain the Lewis acid-doped sulfonic acid resin.

3. The preparation method according to claim 2, wherein The sulfonic acid resin includes one or more of D001-CC, NKC-9, D72, D61, CT175, SK104, SK106, SK116, PK208, PK212, PK216, PK220, PK228, HPK25, K2431, K2621, K2641, X284 and CSP-2.

4. The preparation method according to claim 2, wherein The Lewis acid includes one or more of aluminum chloride, zinc chloride, zinc bromide, zirconium chloride, ferric chloride, ferric bromide, niobium pentachloride, tin tetrachloride and nickel chloride.

5. The preparation method according to claim 4, wherein The mass ratio of the Lewis acid to the sulfonic acid resin is 0.05:1 to 0.25:

1.

6. The preparation method according to claim 2, wherein The heat treatment is carried out under stirring conditions; the heat treatment is heating to boiling; and the lower alcohol is methanol or ethanol.

7. The preparation method according to claim 1, wherein The mass ratio of the 2-pentylidenecyclopentanone to methanol is 1:1 to 1:6; the mass ratio of the 2-pentylidenecyclopentanone to the catalyst is 100:5 to 100:

80.

8. The preparation method according to claim 1, wherein The temperature of the continuous isomerization reaction is 110° C. to 160° C., the pressure is 0.9 MPa to 4.5 MPa, and the reaction time is 0.5 h to 12 h.

9. The preparation method according to claim 1 or 8, wherein The continuous isomerization reaction is carried out by passing a mixed solution of 2-pentylenecyclopentanone and methanol into a fixed bed reactor fixed with a catalyst to carry out the continuous isomerization reaction.

10. The preparation method according to claim 9, characterized in that The flow rate of the mixed solution of 2-pentylenecyclopentanone and methanol is 50 to 200 g / h.

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