CN114904544A - Composite catalyst for preparing cyclohexene by cyclohexanol liquid-phase catalytic dehydration and preparation method and application thereof - Google Patents
Composite catalyst for preparing cyclohexene by cyclohexanol liquid-phase catalytic dehydration and preparation method and application thereof Download PDFInfo
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Abstract
The invention relates to the field of cyclohexene chemical synthesis, and discloses a composite catalyst for preparing cyclohexene through cyclohexanol liquid-phase catalytic dehydration, and a preparation method and application thereof; the composite catalyst consists of concentrated phosphoric acid and aluminum sulfate octadecahydrate, and the preparation method comprises the following steps: adding aluminum sulfate octadecahydrate into a ball milling tank, adding zirconium beads, and carrying out low-speed ball milling; weighing the aluminum sulfate octadecahydrate after ball milling, adding the aluminum sulfate octadecahydrate into a beaker, slowly adding concentrated phosphoric acid into the aluminum sulfate octadecahydrate while stirring; and after the dropwise addition is finished, carrying out ultrasonic stirring, and uniformly stirring to obtain the liquid composite catalyst. The composite catalyst of the invention mixes the solid acid and the liquid acid for use, fully exerts the advantages of strong acidity of the liquid acid and high selectivity and activity of the solid acid, and obviously improves the selectivity and yield of the cyclohexene; the catalyst is non-toxic and pollution-free, has good repeated recoverability and strong catalytic function; the consumption of liquid acid is reduced, the production cost is reduced, and the economic benefit is improved.
Description
Technical Field
The invention relates to the field of cyclohexene chemical synthesis, in particular to a composite catalyst for preparing cyclohexene through cyclohexanol liquid-phase catalytic dehydration, and a preparation method and application thereof.
Background
Cyclohexene is an important organic chemical raw material, is commonly used in the aspects of medicines, pesticide intermediates and high polymer synthesis, is also used as an extracting agent in the petroleum industry, a stabilizer of high-octane gasoline, a solvent in chemical production, a preparation catalyst and the like, and is an important organic compound. The industry is currently producing it by either a sulfuric or phosphoric acid catalyzed liquid phase dehydration process or partial hydrogenation of benzene. Although the sulfuric acid catalysis method is a classical method and has mature process, the strong oxidizing property of concentrated sulfuric acid can cause reactants and products to be carbonized to generate a large amount of black carbon slag; in addition, the strong corrosivity of the concentrated sulfuric acid causes great corrosion to equipment, and SO is generated at the same time 2 And the like, cause environmental pollution, and the yield of the product is not too high. Phosphoric acid is preferred over sulfuric acid, but is more costly. The partial hydrogenation method of benzene has the problems of high catalyst preparation cost and serious benzene pollution, and is not suitable for production in laboratories and small enterprises.
Compared with liquid acid, the solid acid has the characteristics of strong activity, high selectivity, no corrosion, no pollution, easy separation from catalytic reaction products and the like, and is widely used in petroleum refining and organic synthesis industries. Novel solid acid catalysts such as p-toluenesulfonic acid, stannic chloride, ferric chloride, sodium bisulfate and the like are explored at home and abroad. These catalysts are easy to store and use, have low environmental pollution and low equipment corrosion, but have low acid strength and certain limitation on the reaction requiring strong acid. Some cyclohexene prepared by dehydrating cyclohexanol has low catalytic activity and some cyclohexene prepared by dehydrating cyclohexanol has high price. Therefore, it is necessary to search for an ideal catalyst suitable for the preparation of cyclohexene by dehydration of cyclohexanol.
Disclosure of Invention
Aiming at the technical problems, the invention provides a composite catalyst for preparing cyclohexene by cyclohexanol liquid-phase catalytic dehydration and a preparation method and application thereof.
The composite catalyst for preparing cyclohexene by cyclohexanol liquid-phase catalytic dehydration is composed of concentrated phosphoric acid and aluminum sulfate octadecahydrate, and the mass ratio of the concentrated phosphoric acid to the aluminum sulfate octadecahydrate is (26: 1) - (34: 1).
The mass ratio of the concentrated phosphoric acid to the aluminum sulfate octadecahydrate is 30: 1.
A preparation method of a composite catalyst for preparing cyclohexene by cyclohexanol liquid-phase catalytic dehydration comprises the following steps:
(1) adding aluminum sulfate octadecahydrate into a ball milling tank, adding zirconium beads, and carrying out low-speed ball milling;
(2) weighing the aluminum sulfate octadecahydrate after ball milling, adding the aluminum sulfate octadecahydrate into a beaker, slowly adding concentrated phosphoric acid into the aluminum sulfate octadecahydrate while stirring;
(3) and after the dropwise addition is finished, carrying out ultrasonic stirring, and uniformly stirring to obtain the liquid composite catalyst.
The size of the aluminum sulfate octadecahydrate powder ground in the step (1) is 1-100 mu m.
The ball milling in the step (1) is carried out by adopting a common crushing ball mill or a super-energy ball mill, the ball milling rotating speed is 250-350 r/min, and the ball milling time is 10-40 min.
The stirring treatment in the step (2) is mechanical stirring, the stirring speed is 100-300 r/min, and the stirring time is 10-60 min.
The ultrasonic stirring power in the step (3) is 20-40 kHz, the rotating speed is 100-1000 r/min, and the time is 5-60 min.
The application of the composite catalyst for preparing cyclohexene by cyclohexanol liquid-phase catalytic dehydration in the cyclohexene preparation process comprises the following steps:
(1) adding cyclohexanol and composite catalyst into a round-bottom flask, slowly heating with slow fire to boil the mixture, slowly evaporating out turbid liquid containing water, and controlling the temperature at the top of a distillation column to be not more than 80-90 ℃;
(2) pouring the distillate into a separating funnel, standing for layering, and separating out a lower water layer; adding saturated salt solution for washing, shaking up, standing for layering, and separating out lower layer water; adding sodium carbonate solution for washing, vibrating uniformly, standing for layering, and separating out lower-layer water;
(3) pouring the upper layer crude product into a small dry conical bottle from the upper opening of a funnel, adding anhydrous calcium chloride, plugging and standing;
(4) filtering to remove calcium chloride to obtain liquid product cyclohexene.
The mass ratio of the cyclohexanol in the step (1) to the composite catalyst is (1.1: 1) - (1.4: 1), and the heating time is 15 min; the mass concentration of the sodium carbonate solution in the step (2) is 5 percent; the standing time in the step (3) is 0.5 h.
Compared with the prior art, the invention mainly has the following beneficial technical effects:
1. the composite catalyst of the invention mixes the solid acid and the liquid acid for use, fully exerts the advantages of strong acidity of the liquid acid, high selectivity and strong activity of the solid acid, and obviously improves the selectivity and the yield of the cyclohexene.
2. The method is original in the invention, and has the advantages of no toxicity, no pollution, good repeated recoverability and strong catalytic function.
3. The composite catalyst of the invention has the advantages of reduced liquid acid consumption, reduced production cost and improved economic benefit.
4. The preparation method of the composite catalyst is simple and reliable, and is favorable for popularization.
Drawings
FIG. 1 is a scanning electron micrograph of aluminum sulfate octadecahydrate after grinding in example 2;
FIG. 2 is an infrared spectrum of cyclohexene prepared in example 2;
FIG. 3 is a gas chromatography spectrum of cyclohexene prepared in example 2;
FIG. 4 is a gas chromatogram of cyclohexene prepared by the sixth catalyst of the repetitive experiments of example 2.
Detailed Description
The present invention will be described in detail with reference to specific examples.
Example 1
Preparation of the composite catalyst:
adding aluminum sulfate octadecahydrate into a ball milling tank, adding 100g of zirconium beads, and carrying out low-speed ball milling by adopting a common crushing ball mill or a super-energy ball mill, wherein the ball milling speed is 250r/s, and the ball milling time is 40 min; weighing 0.5g of aluminum sulfate octadecahydrate after ball milling, adding the weighed material into a beaker, taking 9ml of concentrated phosphoric acid by a pipette, slowly adding the concentrated phosphoric acid into the aluminum sulfate octadecahydrate while dropwise adding, and mechanically stirring the mixture, wherein the stirring speed is 100/min, and the stirring time is 60 min; after the dropwise addition is finished, ultrasonic stirring is carried out for 60min under the conditions that the power is 20KHz and the rotating speed is 100 r/min.
The size of the milled aluminum sulfate octadecahydrate powder is 1 to 100 μm. Since the density of concentrated phosphoric acid is 1.874g/mL, the mass of 9mL of concentrated phosphoric acid is 16.866g, it follows that: the mass ratio of the concentrated phosphoric acid to the aluminum sulfate octadecahydrate is 16.866: 0.5 ≈ 34: 1.
Preparation of cyclohexene:
(1) adding the above catalyst and 20ml cyclohexanol into 100ml round bottom flask, slowly heating with slow fire to boil the mixture, slowly evaporating out turbid liquid containing water, controlling the temperature at the top of distillation column to be not more than 80-90 deg.C, and heating for 15 min. The mass of 20ml of cyclohexanol is 20ml multiplied by 0.9416g/cm ═ 18.832g, and the mass ratio of cyclohexanol to composite catalyst is 18.832: (16.866 + 0.5) ≈ 1.1: 1.
(2) Pouring the distillate into a separating funnel, standing for layering, and separating out a lower water layer; adding 5ml of saturated salt water, washing, shaking uniformly, standing for layering, and separating out lower-layer water; adding 5ml of 5% sodium carbonate solution, washing, uniformly vibrating, standing for layering, and separating out lower-layer water; pouring the upper layer crude product into a small dry conical bottle from the upper opening of a funnel, adding 1-2g of anhydrous calcium chloride, plugging, and standing for 0.5 h; calcium chloride was filtered off to obtain a product liquid cyclohexene with a mass of 13.7094g and a yield of 88.48% (yield of cyclohexene = actual yield of cyclohexene/theoretical yield of cyclohexene).
(3) And analyzing the product composition by using a gas chromatograph, calculating the product concentration by using an FID (field induced degradation) detector and an area correction normalization method, and further calculating the selectivity of the cyclohexene. Further, the cyclohexene selectivity was found to be 90.24%.
Example 2
Preparation of the composite catalyst:
adding aluminum sulfate octadecahydrate into a ball milling tank, adding 100g of zirconium beads, and carrying out low-speed ball milling by adopting a common crushing ball mill or a super-energy ball mill, wherein the ball milling speed is 280r/s, and the ball milling time is 20 min; weighing 0.5g of aluminum sulfate octadecahydrate after ball milling, adding the weighed material into a beaker, taking 8ml of concentrated phosphoric acid by a pipette, slowly adding the concentrated phosphoric acid into the aluminum sulfate octadecahydrate while dropwise adding the concentrated phosphoric acid, and mechanically stirring the mixture, wherein the stirring speed is 200r/min, and the stirring time is 30 min; after the dropwise addition is finished, the mixture is ultrasonically stirred for 30min under the conditions that the power is 30KHz and the rotating speed is 500 r/min.
The size of the milled aluminum sulfate octadecahydrate powder is 1 to 100 μm. Since the density of concentrated phosphoric acid is 1.874g/mL, the mass of 8mL of concentrated phosphoric acid is 14.992g, thus obtaining: the mass ratio of the concentrated phosphoric acid to the aluminum sulfate octadecahydrate is 14.992: 0.5 ≈ 30: 1.
Preparation of cyclohexene:
(1) adding the above catalyst and 20ml cyclohexanol into 100ml round bottom flask, slowly heating with slow fire to boil the mixture, slowly evaporating out turbid liquid containing water, controlling the temperature at the top of distillation column to be not more than 80-90 deg.C, and heating for 15 min. The mass of 20ml of cyclohexanol is 20ml multiplied by 0.9416g/cm ═ 18.832g, and the mass ratio of cyclohexanol to composite catalyst is 18.832: (14.992 + 0.5) ≈ 1.2: 1.
(2) Pouring the distillate into a separating funnel, standing for layering, and separating out a lower water layer; adding 5ml of saturated salt water, washing, shaking uniformly, standing for layering, and separating out lower-layer water; adding 5ml of 5% sodium carbonate solution, washing, vibrating uniformly, standing for layering, and separating out lower water layer; pouring the upper layer crude product into a small dry conical bottle from the upper opening of a funnel, adding 1-2g of anhydrous calcium chloride, plugging, and standing for 0.5 h; calcium chloride was filtered off to obtain a product liquid cyclohexene with a mass of 14.3562g and a yield of 92.65% (yield of cyclohexene = actual yield of cyclohexene/theoretical yield of cyclohexene).
(3) The milled aluminum sulfate octadecahydrate was scanned by Scanning Electron Microscope (SEM) to obtain an SEM image as shown in FIG. 1. From fig. 1, it can be seen that, after low-speed ball milling, the length of the aluminum sulfate octadecahydrate is about 20 μm, and the aluminum sulfate octadecahydrate can also be used as a carrier to better play the catalytic role of an active substance, so that the yield of cyclohexene is increased.
The synthesized cyclohexene is analyzed by infrared spectroscopy, the spectrogram of which is shown in figure 2, and the infrared spectroscopy shows that the main characteristic absorption peaks are as follows: at 3022cm -1 The peak at 2927cm appears = CH stretching vibration absorption peak -1 、2854cm -1 The peak appears at 1651cm, where-CH 2-stretching vibration absorption peak is -1 A C = C stretching vibration absorption peak appears. By comparison, the infrared spectrogram is consistent with a standard spectrogram in a spectral library of an AVATAR-360FT-IR spectrometer.
And analyzing the product composition by using a gas chromatograph, detecting by using an FID detector, and further calculating the selectivity of the cyclohexene. From FIG. 3, t can be seen R And the reaction time is 1.04min, namely the characteristic peak of the cyclohexene, and the product concentration is calculated according to an area correction normalization method, so that the selectivity of the cyclohexene is 93.08%.
The repeatability experiment of the composite catalyst is as follows:
after reacting for 15min, stopping heating, adding 20ml of cyclohexanol after cooling without separating residues, and sequentially carrying out next reaction at the temperature of 80-90 ℃ at the top of the distillation column to investigate the reusability of the catalyst. The experimental result shows that the yield of cyclohexene prepared by dehydrating cyclohexanol by using the composite catalyst is not obviously reduced after 6 times of continuous reaction, and the cyclohexene shows good reutilization property. Referring to table 1, the cyclohexene mass obtained after 6 consecutive passes of the composite catalyst was 14.0938g, the yield was 90.59%, and was only 2.06% lower than the yield 92.65% of the 1 st pass.
TABLE 1 comparison of cyclohexene yields from the repeatability experiments of example 2
| Number of repetitions of composite catalyst | 1 | 2 | 3 | 4 | 5 | 6 |
| Yield of | 92.65% | 92.17% | 91.52% | 91.22% | 90.96% | 90.59% |
And analyzing the product composition by using a gas chromatograph, detecting by using an FID detector, and further calculating the selectivity of the cyclohexene. From FIG. 4, t can be seen R And the reaction time is not less than 1.04min, and the product concentration is calculated according to an area correction normalization method, so that the selectivity of the cyclohexene is 92.01 percent.
Example 3
Preparation of the composite catalyst:
adding aluminum sulfate octadecahydrate into a ball milling tank, adding 100g of zirconium beads, and carrying out low-speed ball milling by adopting a common crushing ball mill or a super-energy ball mill, wherein the ball milling speed is 350r/s, and the ball milling time is 10 min; weighing 0.5g of ball-milled aluminum sulfate octadecahydrate, adding the weighed aluminum sulfate octadecahydrate into a beaker, taking 7ml of concentrated phosphoric acid by a pipette, slowly adding the concentrated phosphoric acid into the aluminum sulfate octadecahydrate while dropwise adding, and mechanically stirring the mixture at a stirring speed of 300r/min for 10 min; after the dropwise addition, the mixture is ultrasonically stirred for 5min under the conditions that the power is 40KHz and the rotating speed is 1000 r/min.
The size of the milled aluminum sulfate octadecahydrate powder is 1 to 100 μm. Since the density of concentrated phosphoric acid is 1.874g/mL, the mass of 7mL of concentrated phosphoric acid is 13.118g, which gives: the mass ratio of the concentrated phosphoric acid to the aluminum sulfate octadecahydrate is 13.118: 0.5 ≈ 26: 1.
Preparation of cyclohexene:
(1) adding the above catalyst and 20ml cyclohexanol into 100ml round bottom flask, slowly heating with slow fire to boil the mixture, slowly evaporating out turbid liquid containing water, controlling the temperature at the top of distillation column to be not more than 80-90 deg.C, and heating for 15 min. The mass of 20ml of cyclohexanol is 20ml multiplied by 0.9416g/cm ═ 18.832g, and the mass ratio of cyclohexanol to composite catalyst is 18.832: (13.118 + 0.5) ≈ 1.4: 1.
(2) Pouring the distillate into a separating funnel, standing for layering, and separating out a lower water layer; adding 5ml of saturated salt water, washing, shaking uniformly, standing for layering, and separating out lower-layer water; adding 5ml of 5% sodium carbonate solution, washing, vibrating uniformly, standing for layering, and separating out lower water layer; pouring the upper layer crude product into a small dry conical bottle from the upper opening of a funnel, adding 1-2g of anhydrous calcium chloride, plugging, and standing for 0.5 h; calcium chloride was filtered off to obtain a product liquid cyclohexene with a mass of 13.0759g and a yield of 84.39% (yield of cyclohexene = actual yield of cyclohexene/theoretical yield of cyclohexene).
(3) And analyzing the product composition by using a gas chromatograph, detecting by using an FID (flame ionization detector), and calculating the product concentration according to an area correction normalization method to further obtain the cyclohexene selectivity of 91.76%.
Comparative example 1
Preparation of cyclohexene:
(1) adding 10ml concentrated phosphoric acid and 20ml cyclohexanol into 100ml round bottom flask by pipette, slowly heating with slow fire to boil the mixture, slowly evaporating out turbid liquid containing water, controlling the temperature at the top of distillation column to be not more than 80-90 deg.C, and heating for 15 min.
(2) Pouring the distillate into a separating funnel, standing for layering, and separating out a lower water layer; adding 5ml of saturated salt water, washing, shaking uniformly, standing for layering, and separating out lower-layer water; adding 5ml of 5% sodium carbonate solution, washing, vibrating uniformly, standing for layering, and separating out lower water layer; pouring the upper layer crude product into a small dry conical bottle from the upper opening of a funnel, adding 1-2g of anhydrous calcium chloride, plugging, and standing for 0.5 h; after filtration, calcium chloride is filtered out, and the product liquid cyclohexene with the mass of 11.3186g and the yield of 73.04% is obtained.
(3) And analyzing the product composition by using a gas chromatograph, detecting by using an FID (field-induced fluorescence) detector, and calculating the product concentration according to an area correction normalization method to obtain the cyclohexene selectivity of 89.34%.
Comparative example 2
Preparation of cyclohexene:
(1) adding 0.5g of ball-milled aluminum sulfate octadecahydrate and 20ml of cyclohexanol into a 100ml round-bottom flask, slowly heating with slow fire to boil the mixture, slowly evaporating out turbid liquid containing water, controlling the temperature at the top of a distillation column to be not more than 80-90 ℃, and heating for 15 min.
(2) Pouring the distillate into a separating funnel, standing for layering, and separating out a lower water layer; adding 5ml of saturated salt water, washing, shaking uniformly, standing for layering, and separating out lower-layer water; adding 5ml of 5% sodium carbonate solution, washing, vibrating uniformly, standing for layering, and separating out lower water layer; pouring the upper layer crude product into a small dry conical bottle from the upper opening of a funnel, adding 1-2g of anhydrous calcium chloride, plugging, and standing for 0.5 h; after filtration, calcium chloride is filtered out, and the product liquid cyclohexene with the mass of 1.0876g and the yield of 7.02% is obtained.
(3) And analyzing the product composition by using a gas chromatograph, detecting by using an FID (flame ionization detector), and calculating the product concentration according to an area correction normalization method to further obtain the cyclohexene selectivity of 87.43%.
See table 2 for comparison of cyclohexene yields and cyclohexene selectivities for the above examples and comparative examples.
TABLE 2 comparison of cyclohexene yield and cyclohexene selectivity for examples and comparative examples
As can be seen from table 2:
1. the composite catalyst prepared by the embodiment of the invention reduces the dosage of liquid acid, reduces the cost, reduces the corrosivity of the liquid acid to equipment, and has higher catalytic activity and selectivity.
2. The cyclohexene yield of comparative example 1 using concentrated phosphoric acid as a catalyst is 73.04%, and the cyclohexene yield of comparative example 2 using aluminum sulfate octadecahydrate as a catalyst is 7.02%, but the yield of 3 examples using concentrated phosphoric acid and aluminum sulfate octadecahydrate as a composite catalyst is 84.39% -92.65%, obviously, the yield of liquid acid concentrated phosphoric acid and solid acid aluminum sulfate octadecahydrate is greatly improved after being used in a composite mode compared with the yield of the liquid acid concentrated phosphoric acid and the solid acid aluminum sulfate octadecahydrate, and the sum of the yields of the liquid acid concentrated phosphoric acid and the solid acid aluminum sulfate octadecahydrate is also obviously improved, which shows that the yield is obviously enhanced in a composite mode of the concentrated phosphoric acid and the aluminum sulfate octadecahydrate.
3. The cyclohexene selectivity of comparative example 1 using concentrated phosphoric acid as a catalyst is 89.34%, the cyclohexene selectivity of comparative example 2 using aluminum sulfate octadecahydrate as a catalyst is 87.43%, but the selectivity of 3 examples using concentrated phosphoric acid and aluminum sulfate octadecahydrate as a composite catalyst is 90.24% -92.01%, obviously, the selectivity of the liquid acid concentrated phosphoric acid and the solid acid aluminum sulfate octadecahydrate is improved after the composite use compared with the single use, and the composite use of the concentrated phosphoric acid and the aluminum sulfate octadecahydrate has a certain synergistic effect on the selectivity.
4. For the 3 example composite catalysts, the amount used in example 2 was moderate, but the cyclohexene yield and selectivity were highest. Therefore, the composite catalyst scheme of example 2 is the best recommended scheme with economical dosage and best effect.
Claims (10)
1. The composite catalyst for preparing cyclohexene by cyclohexanol liquid-phase catalytic dehydration is characterized by consisting of concentrated phosphoric acid and aluminum sulfate octadecahydrate, wherein the mass ratio of the concentrated phosphoric acid to the aluminum sulfate octadecahydrate is (26: 1) - (34: 1).
2. The composite catalyst for preparing cyclohexene through cyclohexanol liquid-phase catalytic dehydration according to claim 1, wherein the composite catalyst comprises: the mass ratio of the concentrated phosphoric acid to the aluminum sulfate octadecahydrate is 30: 1.
3. The preparation method of the composite catalyst for preparing cyclohexene through cyclohexanol liquid-phase catalytic dehydration according to claim 1, comprising the following steps:
(1) adding aluminum sulfate octadecahydrate into a ball milling tank, adding zirconium beads, and carrying out low-speed ball milling;
(2) weighing the aluminum sulfate octadecahydrate after ball milling, adding the aluminum sulfate octadecahydrate into a beaker, slowly adding concentrated phosphoric acid into the aluminum sulfate octadecahydrate while stirring;
(3) and after the dropwise addition is finished, carrying out ultrasonic stirring, and uniformly stirring to obtain the liquid composite catalyst.
4. The method for preparing the composite catalyst for preparing cyclohexene through cyclohexanol liquid-phase catalytic dehydration according to claim 3, wherein the size of the aluminum sulfate octadecahydrate powder after grinding in the step (1) is 1-100 μm.
5. The preparation method of the composite catalyst for preparing cyclohexene through cyclohexanol liquid-phase catalytic dehydration according to claim 3, wherein the ball milling in the step (1) is performed by a common crushing ball mill or a super-energy ball mill, the ball milling rotation speed is 250-350 r/min, and the ball milling time is 10-40 min.
6. The preparation method of the composite catalyst for preparing cyclohexene through cyclohexanol liquid-phase catalytic dehydration according to claim 3, wherein the stirring treatment in the step (2) is mechanical stirring, the stirring speed is 100-300 r/min, and the stirring time is 10-60 min.
7. The preparation method of the composite catalyst for preparing cyclohexene through cyclohexanol liquid-phase catalytic dehydration according to claim 3, wherein the ultrasonic stirring power in the step (3) is 20-40 kHz, the rotating speed is 100-1000 r/min, and the time is 5-60 min.
8. The use of the composite catalyst for preparing cyclohexene through cyclohexanol liquid-phase catalytic dehydration according to claim 1 or 2 in a cyclohexene preparation process.
9. The application of the composite catalyst for preparing cyclohexene through cyclohexanol liquid-phase catalytic dehydration in the cyclohexene preparation process according to claim 8, wherein the composite catalyst comprises the following steps:
(1) adding cyclohexanol and composite catalyst into a round-bottom flask, slowly heating with slow fire to boil the mixture, slowly evaporating out turbid liquid containing water, and controlling the temperature at the top of a distillation column to be not more than 80-90 ℃;
(2) pouring the distillate into a separating funnel, standing for layering, and separating out a lower water layer; adding saturated salt solution for washing, shaking up, standing for layering, and separating out lower layer water; adding sodium carbonate solution for washing, vibrating uniformly, standing for layering, and separating out lower-layer water;
(3) pouring the crude product on the upper layer into a small dry conical bottle from the upper opening of a funnel, adding anhydrous calcium chloride, plugging, and standing;
(4) filtering to remove calcium chloride to obtain liquid product cyclohexene.
10. The use of the composite catalyst for preparing cyclohexene through liquid-phase catalytic dehydration of cyclohexanol in the process for preparing cyclohexene according to claim 9, wherein the mass ratio of cyclohexanol to composite catalyst in step (1) is (1.1: 1) - (1.4: 1), and the heating time is 15 min; the mass concentration of the sodium carbonate solution in the step (2) is 5 percent; the standing time in the step (3) is 0.5 h.
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| CN202210737994.XA CN114904544A (en) | 2022-06-28 | 2022-06-28 | Composite catalyst for preparing cyclohexene by cyclohexanol liquid-phase catalytic dehydration and preparation method and application thereof |
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Application publication date: 20220816 |