Method for preparing cyclopentyl formaldehyde from cyclopentene

Abstract

The invention relates to the technical field of organic synthesis, in particular to a method for preparing cyclopentylformaldehyde from cyclopentene, which at least comprises the following steps: (1) depolymerizing dicyclopentadiene into cyclopentadiene; (2) selectively hydrogenating cyclopentadiene into cyclopentene through a fixed bed; (3) carrying out hydroformylation reaction on cyclopentene and synthesis gas to obtain crude cyclopentyl formaldehyde; and (4) the crude cyclopentyl formaldehyde is distilled and purified to prepare cyclopentyl formaldehyde, the operation is simple and safe, the cyclopentene conversion rate is high, the product yield is high, and the product purity is high.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, in particular to a method for preparing cyclopentylcarboxaldehyde from cyclopentene. Background Art

[0002] Cyclopentylcarboxaldehyde is a volatile colorless liquid with a special aromatic smell. It is easy to evaporate at room temperature and can be dissolved in a variety of organic solvents such as alcohols, ethers and ketones. Cyclopentylcarboxaldehyde is often used as an intermediate in chemical synthesis to prepare a variety of organic compounds (esters, amides, alcohols, etc.); it can be used as a component of spices or flavors to give the product a unique aromatic aroma; it can also be used in the manufacture of pesticides and has certain applications in the agricultural field, mainly for the synthesis of diketopiperazines as effective and selective oxytocin antagonists, and for the preparation of dihydroquinazoline amines with anti-inflammatory activity.

[0003] At present, the synthesis of cyclopentylcarboxaldehyde mainly includes cyclopentylmethanol oxidation method, cyclopentadiene synthesis method, preparation by Grignard reagent, etc. A Chinese patent (authorization announcement number is CN114605244B) discloses a preparation method of cyclopentylcarboxaldehyde, which uses chlorocyclopentane as a raw material, adds magnesium chips and an initiator to prepare a Grignard reagent, then reacts with DMF, and obtains cyclopentylcarboxaldehyde after hydrolysis with an acidic solution. However, this method has the problem of difficulty in obtaining the source of chlorocyclopentane and a relatively complicated preparation process, and is therefore not conducive to industrial production. Summary of the invention

[0004] In order to solve the above problems, the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, which is simple and safe to operate, has high cyclopentene conversion rate, high product yield and high product purity.

[0005] In one aspect, the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, comprising at least the following steps:

[0006] (1) depolymerizing dicyclopentadiene into cyclopentadiene;

[0007] (2) selective hydrogenation of cyclopentadiene to cyclopentene via a fixed bed;

[0008] (3) hydroformylating cyclopentene with synthesis gas to obtain crude cyclopentylcarboxaldehyde;

[0009] (4) Crude cyclopentylcarboxaldehyde is purified by distillation to obtain cyclopentylcarboxaldehyde.

[0010] As a preferred technical solution, the temperature for depolymerizing dicyclopentadiene into cyclopentadiene in step (1) is ≥260°C.

[0011] Preferably, the step (1) is specifically as follows: dripping the dicyclopentadiene solution into the depolymerization kettle through a feed pump at a feed rate of 3-8 mL / min, heating to 260-300° C., collecting cyclopentadiene, and analyzing the purity of the cyclopentadiene by gas chromatography to be greater than 98%.

[0012] Preferably, the mass ratio of dicyclopentadiene to solvent in the dicyclopentadiene solution is (0.5-2):1, preferably 1:1.

[0013] The depolymerization heat source for depolymerizing dicyclopentadiene into cyclopentadiene is provided by the silicone oil filled in the depolymerization kettle.

[0014] As a preferred technical solution, the step (2) is specifically as follows: cyclopentadiene is mixed with an organic alkane to obtain a cyclopentadiene solution, the cyclopentadiene solution is added into a fixed bed continuous reactor filled with a catalyst layer through a feed pump for catalytic hydrogenation reaction, and cyclopentene is obtained by distillation and purification.

[0015] Preferably, the catalyst layer is palladium supported on alumina, and the mass percentage of palladium in the palladium supported on alumina is 10-30%. Preferably, the catalyst layer is palladium supported on alumina (20-25wt% Pd).

[0016] Preferably, the mass ratio of cyclopentadiene to organic alkane is 1:(1-2), preferably 1:2.

[0017] Preferably, the feed rate of the cyclopentadiene solution is 1-3 mL / min.

[0018] Preferably, the catalytic hydrogenation reaction conditions are: hydrogen flow rate is set to 300-500mL / min, hydrogen-to-oil ratio is 200-300, and space velocity is 1-3h -1 , the temperature is 15-35℃ (normal temperature), and the pressure is 0.1013MPa (normal pressure).

[0019] Preferably, the catalytic hydrogenation reaction conditions are: the hydrogen flow rate is set to 400 mL / min, the hydrogen-to-oil ratio is 200, and the space velocity is 2 h -1 , the temperature is 15-35℃ (normal temperature), and the pressure is 0.1013MPa (normal pressure).

[0020] In the step (2), the cyclopentadiene conversion rate is ≥95%, the cyclopentene selectivity is ≥97%, and the cyclopentene purity is ≥95%.

[0021] As a preferred technical solution, the step (3) is specifically as follows: cyclopentene, triruthenium dodecacarbonyl and tricyclohexylphosphine are added to a high-pressure autoclave equipped with an anchor stirrer, the reactor is replaced with an inert gas and synthesis gas in sequence, the synthesis gas is introduced to a pressure of 2-4 MPa, stirring is started, and the temperature and pressure are increased to react; after the reaction is completed, the temperature is reduced and the pressure is released, and the crude cyclopentyl formaldehyde is obtained after the inert gas replacement.

[0022] Preferably, the addition ratio of cyclopentene, triruthenium dodecacarbonyl and tricyclohexylphosphine is (200-400 g): (20-30 mmol): (100-200 mmol), preferably 300 g: (23-30 mmol): (138-180 mmol).

[0023] Preferably, the inert gas is selected from one of nitrogen, helium and argon, preferably argon.

[0024] Preferably, the CO and H in the synthesis gas 2 The volume ratio is (0.5-2):1, preferably 1:1.

[0025] Preferably, the step (3) is specifically as follows: cyclopentene, triruthenium dodecacarbonyl and tricyclohexylphosphine are added to an autoclave equipped with an anchor stirrer, the reactor is replaced with an inert gas and synthesis gas in sequence, synthesis gas is introduced to 2-4 MPa, stirring is started, the reaction begins after the temperature is increased, and the synthesis gas is continuously added to increase the pressure until the reaction is completed; after the reaction is completed, the temperature is reduced and the pressure is released, and the crude cyclopentyl formaldehyde is obtained after the inert gas is replaced.

[0026] Preferably, the step (3) is specifically as follows: cyclopentene, triruthenium dodecacarbonyl and tricyclohexylphosphine are added to an autoclave equipped with an anchor stirrer, the reactor is replaced with an inert gas and synthesis gas in sequence, synthesis gas is introduced to 3MPa, stirring is started, the stirring speed is 400-600r / min, the reaction begins after the temperature is raised to 160-190°C, and the synthesis gas is continuously supplemented to increase the pressure to 6-8MPa until the reaction is completed, and the reaction time is 6-9h; after the reaction is completed, the temperature is reduced and the pressure is released, and the crude cyclopentyl formaldehyde is obtained after the inert gas is replaced.

[0027] As a preferred technical solution, the step (4) is specifically as follows: the crude cyclopentylcarboxaldehyde is transferred to a distillation device, the vacuum degree is controlled to be above 0.99 MPa, the reduced pressure distillation temperature is set to 130-145° C., and the cyclopentylcarboxaldehyde is distilled out.

[0028] The method for preparing cyclopentylcarboxaldehyde provided by the present invention uses dicyclopentadiene as a raw material, sequentially performs cracking, hydrogenation and hydroformylation reactions to prepare crude cyclopentylcarboxaldehyde, and then performs reduced pressure distillation to obtain a cyclopentylcarboxaldehyde product. The raw materials are easily available, the process flow is simple and easy to operate, continuous feeding and discharging are possible, the production efficiency is high, and industrial production can be easily realized.

[0029] However, in the actual development process, the control of side reaction products under different process conditions varies greatly and will directly affect the conversion rate of cyclopentene and the yield of cyclopentylcarboxaldehyde. Therefore, the coordinated control of each step and each reaction condition is a necessary condition for achieving high conversion rate and high yield of cyclopentylcarboxaldehyde product preparation.

[0030] Specifically, the present invention controls the temperature of the step (1) in which dicyclopentadiene is depolymerized into cyclopentadiene to be ≥260°C, the cracking rate is fast, the purity of the obtained cyclopentadiene is high, and the purity is greater than 98% by gas chromatography analysis, which provides a basis for subsequent reactions. Further, in the process of cyclopentadiene being selectively hydrogenated to become cyclopentene, the hydrogenation reaction of cyclopentadiene is divided into two stages, namely, selective hydrogenation to generate cyclopentene and complete hydrogenation to generate cyclopentane. In the reaction process, a small amount of cyclopentadiene will also be polymerized to generate dicyclopentadiene, and hydrogenation to generate dihydrodicyclopentadiene (2HDCPD) and tetrahydrodicyclopentadiene (4HDCPD), therefore, it is necessary to adopt alumina-supported palladium (20-25wt%Pd) catalyst to cooperate with catalytic hydrogenation reaction conditions to control the hydrogenation reaction as much as possible in the first stage to avoid the generation of by-products. In particular, a fixed bed method is adopted, a supported palladium catalyst (Pd content 20%-25%) is used, and conditions such as hydrogen flow rate, hydrogen-to-oil ratio and space velocity are controlled to achieve extremely high selectivity of cyclopentadiene selective hydrogenation, mild hydrogenation conditions, cyclopentadiene conversion rate ≥95%, cyclopentene selectivity ≥97%, cyclopentene purity ≥95%, and basically no by-product cyclopentane is produced. In addition, the fixed bed method has high efficiency, low energy consumption control, and is easy to realize industrialization.

[0031] Furthermore, by innovatively using cyclopentene and synthesis gas CO and H 2 The hydroformylation reaction was carried out using a ruthenium catalyst and a kettle reaction. An anchor stirrer was preferred. The different stirring forms affected the gas-liquid contact. The anchor stirrer had a unique shape and almost no dead angle in stirring. The mass transfer and heat transfer were uniform, which effectively promoted the reaction of cyclopentene and synthesis gas CO with H 2 The hydroformylation reaction greatly improves the conversion rate of cyclopentene and the yield of cyclopentylcarboxaldehyde. Compared with other technical processes, the process route is shorter, the hydroformylation reaction is controllable, and the safety is high. The source of cyclopentene is simple, which is conducive to the industrial production of cyclopentylcarboxaldehyde. In particular, the addition ratio of cyclopentene, triruthenium dodecacarbonyl, and tricyclohexylphosphine, the CO and H in the synthesis gas are comprehensively controlled. 2The volume ratio, reaction temperature and time of the reaction mixture are as follows: the cyclopentene conversion rate and the cyclopentylcarboxaldehyde yield are both greater than 95%, and there are few by-products.

[0032] The cyclopentylcarboxaldehyde synthesized by the invention has high purity, is often used as an intermediate in chemical synthesis, and has good industrial application value.

[0033] Beneficial Effects

[0034] 1. The present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, which is simple and safe to operate, has high cyclopentene conversion rate, high product yield and high product purity.

[0035] 2. The method for preparing cyclopentylcarboxaldehyde provided by the present invention uses dicyclopentadiene as a raw material, and successively obtains crude cyclopentylcarboxaldehyde through cracking, hydrogenation and hydroformylation reactions, and then obtains the extracted cyclopentylcarboxaldehyde product after vacuum distillation. The raw materials are easily available, the process flow is simple and easy to operate, continuous feeding and discharging are possible, the production efficiency is high, and industrial production can be easily realized.

[0036] 3. The present invention controls the temperature of the step (1) at which dicyclopentadiene is depolymerized into cyclopentadiene to be ≥260° C., and the cracking rate is fast, so that the cyclopentadiene obtained has high purity, and the purity is greater than 98% through gas chromatography analysis, providing a basis for subsequent reactions.

[0037] 4. The present invention adopts a fixed bed method, uses a loaded palladium catalyst (Pd content 20%-25%), and controls conditions such as hydrogen flow rate, hydrogen-to-oil ratio and space velocity to achieve extremely high selectivity of cyclopentadiene selective hydrogenation. The hydrogenation conditions are mild, the cyclopentadiene conversion rate is ≥95%, the cyclopentene selectivity is ≥97%, the cyclopentene purity is ≥95%, and basically no by-product cyclopentane is produced. The fixed bed method has high efficiency, low energy consumption control, and is easy to realize industrialization.

[0038] 5. The present invention innovatively uses cyclopentene and synthesis gas CO and H 2 The hydroformylation reaction was carried out using ruthenium catalyst, through a kettle reaction, preferably an anchor stirrer, which effectively promoted the reaction of cyclopentene and synthesis gas CO with H 2 Compared with other technologies, the hydroformylation process is shorter, the hydroformylation reaction is controllable, and the safety is high. The source of cyclopentene is simple, which is conducive to the industrial production of cyclopentyl formaldehyde. In particular, the addition ratio of cyclopentene, triruthenium dodecacarbonyl, and tricyclohexylphosphine, the addition ratio of CO and H in the synthesis gas, and the addition ratio of cyclopentene, triruthenium dodecacarbonyl, and tricyclohexylphosphine are comprehensively controlled. 2 The volume ratio, reaction temperature and time of the reaction mixture are as follows: the cyclopentene conversion rate and the cyclopentylcarboxaldehyde yield are both greater than 95%, and there are few by-products.

[0039] 6. The cyclopentylcarboxaldehyde synthesized by the present invention has high purity and is often used as an intermediate in chemical synthesis, and has good industrial application value. DETAILED DESCRIPTION

[0040] Example 1

[0041] Embodiment 1 of the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, comprising the following steps:

[0042] (1) depolymerizing dicyclopentadiene into cyclopentadiene;

[0043] (2) selective hydrogenation of cyclopentadiene to cyclopentene via a fixed bed;

[0044] (3) hydroformylating cyclopentene with synthesis gas to obtain crude cyclopentylcarboxaldehyde;

[0045] (4) Crude cyclopentylcarboxaldehyde is purified by distillation to obtain cyclopentylcarboxaldehyde.

[0046] The step (1) specifically comprises: dripping the dicyclopentadiene solution into the depolymerization kettle through a feed pump at a feed rate of 6 mL / min, heating to 280° C., collecting cyclopentadiene, and analyzing the purity of the cyclopentadiene by gas chromatography to be greater than 98%.

[0047] The mass ratio of dicyclopentadiene to the solvent (cyclohexane) in the dicyclopentadiene solution is 1:1.

[0048] The depolymerization heat source for depolymerizing dicyclopentadiene into cyclopentadiene is provided by the silicone oil filled in the depolymerization kettle.

[0049] The step (2) specifically comprises: mixing cyclopentadiene and an organic alkane to obtain a cyclopentadiene solution, adding the cyclopentadiene solution into a fixed bed continuous reactor filled with a catalyst layer through a feed pump for catalytic hydrogenation reaction, and distilling and purifying to obtain cyclopentene.

[0050] The catalyst layer is palladium supported on alumina (20-25 wt % Pd).

[0051] The mass ratio of the cyclopentadiene to the organic alkane (cyclohexane) is 1:2.

[0052] The feed rate of the cyclopentadiene solution was 2 mL / min.

[0053] The catalytic hydrogenation reaction conditions are: hydrogen flow rate is set to 400 mL / min, hydrogen to oil ratio is 200, and space velocity is 2 h -1 , the temperature is 15-35℃ (normal temperature), and the pressure is 0.1013MPa (normal pressure).

[0054] In the step (2), the cyclopentadiene conversion rate is 95%, the cyclopentene selectivity is 97%, and the cyclopentene purity is 95%.

[0055] The step (3) is specifically as follows: cyclopentene, triruthenium dodecacarbonyl and tricyclohexylphosphine are added to an autoclave equipped with an anchor stirrer, the reactor is replaced with argon three times, replaced with synthesis gas three times, the synthesis gas is introduced to 3MPa, stirring is started, the stirring speed is 500r / min, the temperature is raised to 170°C and the reaction begins, the synthesis gas is continuously supplemented and the pressure is increased to 6MPa until the reaction is completed, and the reaction time is 7h; after the reaction is completed, the temperature is lowered to 25°C, the pressure is reduced to 0.1013MPa, and the crude cyclopentyl formaldehyde is obtained after argon is replaced once.

[0056] The addition ratio of the cyclopentene, triruthenium dodecacarbonyl and tricyclohexylphosphine is 300 g: 23 mmol: 138 mmol.

[0057] The inert gas is argon.

[0058] The CO and H in the synthesis gas 2 The volume ratio is 1:1.

[0059] The step (4) specifically comprises: transferring the crude cyclopentylcarboxaldehyde to a distillation device, controlling the vacuum degree at 0.99 MPa, setting the reduced pressure distillation temperature at 140° C., and distilling out the cyclopentylcarboxaldehyde.

[0060] The cyclopentylcarboxaldehyde is colorless and transparent in appearance, the cyclopentene conversion rate is 98%, the cyclopentylcarboxaldehyde yield is 95%, and the GC analysis purity is 99.1%.

[0061] Example 2

[0062] Example 2 of the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, and its specific implementation method is the same as that of Example 1, except that the addition ratio of cyclopentene, triruthenium dodecacarbonyl, and tricyclohexylphosphine is 300g:30mmol:180mmol; the cyclopentene conversion rate is 99%, the cyclopentylcarboxaldehyde yield is 96%, and the GC analysis purity is 98.6%.

[0063] Example 3

[0064] Example 3 of the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, and its specific implementation method is the same as that of Example 1, except that the step (3) is specifically as follows: cyclopentene, triruthenium dodecacarbonyl, and tricyclohexylphosphine are added to an autoclave equipped with an anchor stirrer, the reactor is replaced with argon three times, replaced with synthesis gas three times, the synthesis gas is introduced to 3MPa, stirring is started, the stirring speed is 500r / min, the reaction begins after the temperature is raised to 170°C, and the synthesis gas is continuously supplemented to increase the pressure to 5MPa until the reaction is completed, and the reaction time is 7h; after the reaction is completed, the temperature is lowered to 25°C, the pressure is released to 0.1013MPa, and the crude cyclopentylcarboxaldehyde is obtained after argon is replaced once; the cyclopentene conversion rate is 83%, the cyclopentylcarboxaldehyde yield is 82%, and the GC analysis purity is 98.2%.

[0065] Example 4

[0066] Example 4 of the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, and its specific implementation method is the same as that of Example 1, except that the step (3) is specifically as follows: cyclopentene, triruthenium dodecacarbonyl, and tricyclohexylphosphine are added to an autoclave equipped with an anchor stirrer, the reactor is replaced with argon three times, replaced with synthesis gas three times, the synthesis gas is introduced to 3MPa, stirring is started, the stirring speed is 500r / min, the reaction begins after the temperature is raised to 170°C, and the synthesis gas is continuously supplemented to increase the pressure to 8MPa until the reaction is completed, and the reaction time is 7h; after the reaction is completed, the temperature is lowered to 25°C, the pressure is released to 0.1013MPa, and the argon is replaced once to obtain crude cyclopentylcarboxaldehyde; the cyclopentene conversion rate is 97%, the cyclopentylcarboxaldehyde yield is 95%, and the GC analysis purity is 98.3%.

[0067] Example 5

[0068] Example 5 of the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, and its specific implementation method is the same as that of Example 1, except that the step (3) is specifically as follows: cyclopentene, triruthenium dodecacarbonyl, and tricyclohexylphosphine are added to an autoclave equipped with an anchor stirrer, the reactor is replaced with argon three times, replaced with synthesis gas three times, the synthesis gas is introduced to 3MPa, stirring is started, the stirring speed is 500r / min, the temperature is raised to 170°C and the reaction begins, the synthesis gas is continuously supplemented and the pressure is increased to 6MPa until the reaction is completed, and the reaction time is 5h; after the reaction is completed, the temperature is lowered to 25°C, the pressure is released to 0.1013MPa, and the argon is replaced once to obtain crude cyclopentylcarboxaldehyde; the cyclopentene conversion rate is 87%, the cyclopentylcarboxaldehyde yield is 84%, and the GC analysis purity is 98.5%.

[0069] Example 6

[0070] Example 6 of the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, and its specific implementation method is the same as that of Example 1, except that the step (3) is specifically as follows: cyclopentene, triruthenium dodecacarbonyl, and tricyclohexylphosphine are added to an autoclave equipped with an anchor stirrer, the reactor is replaced with argon three times, replaced with synthesis gas three times, the synthesis gas is introduced to 3MPa, stirring is started, the stirring speed is 500r / min, the reaction begins after the temperature is raised to 170°C, and the synthesis gas is continuously supplemented to increase the pressure to 6MPa until the reaction is completed, and the reaction time is 9h; after the reaction is completed, the temperature is lowered to 25°C, the pressure is released to 0.1013MPa, and the argon is replaced once to obtain crude cyclopentylcarboxaldehyde; the cyclopentene conversion rate is 98%, the cyclopentylcarboxaldehyde yield is 95%, and the GC analysis purity is 98.5%.

[0071] Example 7

[0072] Example 7 of the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, and its specific implementation method is the same as that of Example 1, except that the step (3) is specifically as follows: cyclopentene, triruthenium dodecacarbonyl, and tricyclohexylphosphine are added to an autoclave equipped with an anchor stirrer, the reactor is replaced with argon three times, replaced with synthesis gas three times, the synthesis gas is introduced to 3MPa, stirring is started, the stirring speed is 500r / min, the reaction begins after the temperature is raised to 150°C, and the synthesis gas is continuously supplemented to increase the pressure to 6MPa until the reaction is completed, and the reaction time is 7h; after the reaction is completed, the temperature is lowered to 25°C, the pressure is released to 0.1013MPa, and the argon is replaced once to obtain crude cyclopentylcarboxaldehyde; the cyclopentene conversion rate is 78%, the cyclopentylcarboxaldehyde yield is 79%, and the GC analysis purity is 97.6%.

[0073] Example 8

[0074] Example 8 of the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, and its specific implementation method is the same as that of Example 1, except that the step (3) is specifically as follows: cyclopentene, triruthenium dodecacarbonyl, and tricyclohexylphosphine are added to an autoclave equipped with an anchor stirrer, the reactor is replaced with argon three times, replaced with synthesis gas three times, the synthesis gas is introduced to 3MPa, stirring is started, the stirring speed is 500r / min, the reaction begins after the temperature is raised to 190°C, and the synthesis gas is continuously supplemented to increase the pressure to 6MPa until the reaction is completed, and the reaction time is 7h; after the reaction is completed, the temperature is lowered to 25°C, the pressure is released to 0.1013MPa, and the crude cyclopentylcarboxaldehyde is obtained after argon is replaced once; the cyclopentene conversion rate is 99%, the cyclopentylcarboxaldehyde yield is 97%, and the GC analysis purity is 98.3%.

[0075] Example 9

[0076] Example 9 of the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, and its specific implementation method is the same as that of Example 1, except that the autoclave equipped with an anchor stirrer is replaced by an autoclave equipped with a 5-blade open turbine stirring impeller; the cyclopentene conversion rate is 46%, the cyclopentylcarboxaldehyde yield is 40%, and the GC analysis purity is 97.5%.

[0077] Example 10

[0078] Example 10 of the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, and its specific implementation method is the same as that of Example 1, except that the autoclave equipped with an anchor agitator is replaced by an autoclave equipped with a 5-blade paddle stirring paddle; the cyclopentene conversion rate is 50%, the cyclopentylcarboxaldehyde yield is 45%, and the GC analysis purity is 97.9%.

[0079] Embodiment 11

[0080] Example 11 of the present invention provides a method for preparing cyclopentylcarboxaldehyde from cyclopentene, and its specific implementation method is the same as that of Example 1, except that the autoclave equipped with an anchor stirrer is replaced by an autoclave equipped with a spiral stirring paddle; the cyclopentene conversion rate is 60%, the cyclopentylcarboxaldehyde yield is 56%, and the GC analysis purity is 97.6%.

Claims

1. A method for preparing cyclopentylcarboxaldehyde from cyclopentene, characterized in that: At least the following steps are included: (1) depolymerizing dicyclopentadiene into cyclopentadiene; (2) selective hydrogenation of cyclopentadiene to cyclopentene via a fixed bed; (3) hydroformylating cyclopentene with synthesis gas to obtain crude cyclopentylcarboxaldehyde; (4) Crude cyclopentylcarboxaldehyde is purified by distillation to obtain cyclopentylcarboxaldehyde.

2. The method for preparing cyclopentylcarboxaldehyde from cyclopentene according to claim 1, characterized in that: The temperature of depolymerizing dicyclopentadiene into cyclopentadiene in step (1) is ≥260°C.

3. The method for preparing cyclopentylcarboxaldehyde from cyclopentene according to claim 2, characterized in that: The step (2) specifically comprises: mixing cyclopentadiene and an organic alkane to obtain a cyclopentadiene solution, adding the cyclopentadiene solution into a fixed bed continuous reactor filled with a catalyst layer through a feed pump for catalytic hydrogenation reaction, and distilling and purifying to obtain cyclopentene.

4. The method for preparing cyclopentylcarboxaldehyde from cyclopentene according to claim 3, characterized in that: The catalyst layer is aluminum oxide-supported palladium, and the mass proportion of palladium in the aluminum oxide-supported palladium is 10-30%.

5. The method for preparing cyclopentylcarboxaldehyde from cyclopentene according to claim 4, characterized in that: The catalytic hydrogenation reaction conditions are: hydrogen flow rate is set to 300-500mL / min, hydrogen-to-oil ratio is 200-300, and space velocity is 1-3h -1 , temperature is 15-35℃, and pressure is 0.1013MPa.

6. The method for preparing cyclopentylcarboxaldehyde from cyclopentene according to claim 5, characterized in that: In the step (2), the cyclopentadiene conversion rate is ≥95%, the cyclopentene selectivity is ≥97%, and the cyclopentene purity is ≥95%.

7. The method for preparing cyclopentylcarboxaldehyde from cyclopentene according to claim 6, characterized in that: The step (3) specifically comprises: adding cyclopentene, triruthenium dodecacarbonyl and tricyclohexylphosphine respectively into a high pressure autoclave equipped with an anchor stirrer, replacing the autoclave with an inert gas and synthesis gas in sequence, introducing synthesis gas to 2-4 MPa, starting stirring, and starting the reaction after heating, and continuing to feed synthesis gas to increase the pressure until the reaction is completed; after the reaction is completed, cooling and releasing the pressure, and discharging the material after inert gas replacement to obtain crude cyclopentyl formaldehyde.

8. The method for preparing cyclopentylcarboxaldehyde from cyclopentene according to claim 7, characterized in that: The addition ratio of the cyclopentene, triruthenium dodecacarbonyl and tricyclohexylphosphine is (200-400 g): (20-30 mmol): (100-200 mmol).

9. The method for preparing cyclopentylcarboxaldehyde from cyclopentene according to claim 8, characterized in that: The volume ratio of CO and H2 in the synthesis gas is (0.5-2):

1.

10. The method for preparing cyclopentylcarboxaldehyde from cyclopentene according to claim 9, characterized in that: The step (3) is specifically as follows: cyclopentene, triruthenium dodecacarbonyl and tricyclohexylphosphine are added to a high pressure autoclave equipped with an anchor stirrer, the reactor is replaced with an inert gas and a synthesis gas in sequence, the synthesis gas is introduced to 2-4 MPa, stirring is started, the stirring speed is 400-600 r / min, the reaction begins after the temperature is raised to 160-190° C., the synthesis gas is continuously introduced to increase the pressure to 6-8 MPa until the reaction is completed, and the reaction time is 6-9 hours; after the reaction is completed, the temperature is reduced and the pressure is released, and the crude cyclopentyl formaldehyde is obtained after the inert gas is replaced.