Method for preparing 1-methoxy-2-acetone by fluidized bed and application

Abstract

The invention discloses a method for preparing 1-methoxy-2-acetone by a fluidized bed, which comprises the following steps: S1, adding a catalyst into the fluidized bed, and introducing 1-methoxy-2-propanol for preheating; s2, controlling pressure, temperature and catalytic reaction to obtain a liquid-phase mixture; s3, rectifying and separating the liquid-phase mixture, returning the 1-methoxy-2-propanol to the riser reactor for continuous reaction, and extracting the 1-methoxy-2-acetone; and S4, circulating the non-deactivated part of the catalyst for continuous reaction, discharging the deactivated catalyst from a discharge port, and supplementing the catalyst for continuous reaction. The fluidized bed is adopted for production, the deactivated catalyst is discharged from the deactivated catalyst outlet, and the fresh catalyst is supplemented, so that online replacement and stable production of the catalyst are realized, and the reaction efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of chemical preparation of acyclic compounds, in particular to a method for preparing 1-methoxy-2-propanone in a fluidized bed and its application. BACKGROUND

[0002] 1-methoxy-2-propanone is an important chemical raw material, which is widely used in the manufacture of paint, cleaning agent, dye, pesticide and other products. At present, 1-methoxy-2-propanone is usually prepared by dehydrogenation of 1-methoxy-2-propanol as raw material in a fixed bed by adding catalyst. However, the service life of the catalyst is short, and it is difficult to replace the deactivated catalyst. The fixed bed needs to be shut down for catalyst replacement, and the reaction efficiency is low. If a fluidized bed is used for continuous production, the reaction efficiency of the conventional catalyst in the fluidized bed is not good, so it is very important to develop a high-efficiency catalyst for the preparation of 1-methoxy-2-propanone in a fluidized bed.

[0003] Chinese invention patent CN107628933B discloses a continuous production process for synthesizing 1-methoxy-2-propanone by direct dehydrogenation of 1-methoxy-2-propanol. Under the conditions of reaction temperature 220-350℃, reaction pressure 0-1.0MPa, mass space velocity 0.5-6h -1 The conversion rate of the raw material can reach more than 70%, and the selectivity of 1-methoxy-2-propanone can reach more than 98%, but the active components of the catalyst are copper: 25.4wt%; magnesium: 2.5wt%; calcium: 1.25wt%; potassium 1.0wt%, and the rest is silicon dioxide. The preparation process of the catalyst is complex. Chinese invention patent CN102159311B discloses a method for continuously preparing amine using aluminum-copper catalyst, and the catalytically active material of the catalyst contains 20-75wt% of aluminum oxide, 20-75wt% of CuO containing oxygen compounds, and the catalyst is reduced at 200℃ in a hydrogen stream to prepare amine, but it does not involve alcohol dehydrogenation reaction. SUMMARY

[0004] In order to develop a high-efficiency catalyst for the preparation of 1-methoxy-2-propanone in a fluidized bed, the first aspect of the present application provides a method for preparing 1-methoxy-2-propanone in a fluidized bed, which comprises the following steps:

[0005] S1 adding catalyst into the riser reactor of the fluidized bed, and preheating by passing 1-methoxy-2-propanol;

[0006] S2 controlling the pressure and temperature of the riser reactor, and catalyzing to obtain a liquid phase mixture of 1-methoxy-2-propanone and 1-methoxy-2-propanol;

[0007] S3 distillates the liquid phase mixture obtained in step S2, 1-methoxy-2-propanol is returned to the riser reactor for further reaction, and 1-methoxy-2-propanone is extracted;

[0008] S4 the non-inactivated part of the catalyst after the reaction in step S2 is returned to the riser reactor for further reaction, the inactivated catalyst is discharged from the discharge port, and then the catalyst is supplemented and the reaction is continued.

[0009] As an embodiment, the riser reactor contains a U-shaped tube heater, and the heating medium is heat-conducting oil. The inner diameter of the riser reactor is 89 mm, and the height of the riser reactor is 1500 mm.

[0010] As an embodiment, the method for preparing 1-methoxy-2-propanone by a fluidized bed comprises the following steps:

[0011] S1 air enters the riser reactor through the gas distributor from the reaction gas inlet, and 1-methoxy-2-propanol is preheated by the U-shaped tube heater, and the catalyst is added to the fluidized bed in the riser reactor;

[0012] S2 the pressure and temperature of the riser reactor are controlled, 1-methoxy-2-propanol is catalytically reacted with the catalyst to generate 1-methoxy-2-propanone and hydrogen, obtaining a liquid phase mixture of 1-methoxy-2-propanone and 1-methoxy-2-propanol and hydrogen;

[0013] S3 the liquid phase mixture and hydrogen obtained in step S2 are separated by a cyclone separator, the hydrogen is filtered by a precision filter and discharged from the reaction gas outlet, the liquid phase mixture is distillated, 1-methoxy-2-propanol is returned to the riser reactor for further reaction through the vertical section of the downcomer and the inclined section of the downcomer, and 1-methoxy-2-propanone is extracted;

[0014] S4 the non-inactivated part of the catalyst after the reaction in step S2 is returned to the riser reactor for further reaction through the vertical section of the downcomer and the inclined section of the downcomer, the inactivated catalyst is discharged from the inactivated catalyst discharge port, and then the catalyst is supplemented by adding fresh catalyst through the catalyst addition port, and the reaction is continued, realizing online partial replacement of the catalyst and stabilizing the production.

[0015] The dehydrogenation reaction of the present application is a strong endothermic reaction, which requires timely heat supply, and the heat transfer effect of the fixed bed reactor is generally limited, which restricts the large-scale of a single fixed reactor and the reaction space velocity. The particle flowability of the copper-based catalyst makes the bed layer have good mass transfer and heat transfer performance, the internal pressure of the bed layer drops, the temperature is uniform and easy to control, and it is particularly suitable for strong endothermic and strong exothermic reactions; the inactivated catalyst is conveniently discharged and fresh catalyst is conveniently supplemented, and the production can be continuously carried out, avoiding the problems of shutdown and difficult catalyst replacement of the fixed bed with tube.

[0016] As an implementation form, the preheating temperature in step S1 is 150-180℃.

[0017] As an implementation form, the preheating temperature in step S1 is 150℃.

[0018] As an implementation form, the reaction temperature in step S2 is 200-280℃.

[0019] As an implementation form, the reaction temperature in step S2 is 200-270℃.

[0020] As an implementation form, the reaction pressure in step S2 is 0.05-0.1MPa.

[0021] As an implementation form, the reaction pressure in step S2 is 0.05MPa.

[0022] As an implementation form, the residence time of the catalyst is 0.02-0.07h.

[0023] As an implementation form, the residence time of the catalyst is 0.05h.

[0024] As an implementation form, the catalyst is a copper-based catalyst, and the copper-based catalyst is an alumina-supported copper-based catalyst.

[0025] As an implementation form, the preparation method of the copper-based catalyst comprises the following steps:

[0026] M1 configures a copper nitrate aqueous solution;

[0027] M2 impregnates the alumina into the copper nitrate aqueous solution for 3-8h, and after taking out, dries at 100-150℃ for 3-8h, and calcines at 350-450℃ for 10-15h to obtain the copper-based catalyst.

[0028] As an implementation form, the preparation method of the copper-based catalyst comprises the following steps:

[0029] M1 configures a copper nitrate aqueous solution;

[0030] M2 impregnates the alumina into the copper nitrate aqueous solution for 5h, and after taking out, dries at 120℃ for 5h, and calcines at 400℃ for 12h to obtain the copper-based catalyst.

[0031] As an implementation form, the mass concentration of the copper nitrate aqueous solution is 20-30wt%.

[0032] As an implementation form, the mass concentration of the copper nitrate aqueous solution is 25wt%.

[0033] As an implementation form, the alumina is spherical gamma-alumina, the particle size of the spherical gamma-alumina is 20-120 μm, the specific surface area is 120-150 m 2 / g.

[0034] As an implementation form, the alumina is spherical gamma-alumina, the particle size of the spherical gamma-alumina is 70 μm.

[0035] The inventors found in the experiment that the continuous reaction can be realized, the conversion rate of 1-methoxy-2-propanol is increased, and the selectivity of 1-methoxy-2-propanone is optimized by using a copper-based dehydrogenation catalyst to catalyze the conversion of 1-methoxy-2-propanol into 1-methoxy-2-propanone in a fluidized bed. It is speculated that the possible reason is that the spherical gamma-alumina is used as a carrier to load copper ions, and the specific surface area of the gamma-alumina is large and the porosity is high, so that the loading rate of copper ions is increased and the catalytic activity of the copper-based catalyst is increased.

[0036] In addition, the particle size of the obtained copper-based catalyst is small, which is 20-120 μm, so that the copper-based catalyst can realize flow when reacting in a fluidized bed reactor, the copper-based catalyst can continue to synthesize 1-methoxy-2-propanone by dehydrogenating the unreacted 1-methoxy-2-propanol, the copper-based catalyst with decreased catalytic activity can be discharged from the outlet at the lower end of the downcomer, and fresh catalyst is supplemented from the inlet at the lower end of the downcomer, so that the catalyst can be replaced online, and the effect of stable production is realized.

[0037] The inventors further found that the spherical gamma-alumina has good heat resistance, good formability, strong surface acidity and certain surface basicity, so that the loading of copper ions can be further increased, the catalytic activity of the copper-based catalyst is improved, and the one-way conversion rate of 1-methoxy-2-propanol is further optimized.

[0038] The second aspect of the present application provides an application of a method for preparing 1-methoxy-2-propanone in a fluidized bed, which is applied to the continuous preparation of 1-methoxy-2-propanone.

[0039] Compared with the prior art, the present application has the following beneficial effects:

[0040] (1) The method for preparing 1-methoxy-2-propanone in a fluidized bed of the present application uses 1-methoxy-2-propanol as a raw material, and the copper-based catalyst can directly contact and react to dehydrogenate to obtain 1-methoxy-2-propanone, so that the reaction efficiency is high, the one-way conversion rate of 1-methoxy-2-propanol is increased, and the selectivity of 1-methoxy-2-propanone is improved.

[0041] (2) The method for preparing 1-methoxy-2-propanone by fluidized bed, which uses fluidized bed to produce, discharges the deactivated catalyst at the outlet of the deactivated catalyst, supplements fresh catalyst, realizes online replacement of the catalyst and stable production.

[0042] (3) The method for preparing 1-methoxy-2-propanone by fluidized bed, which uses spherical γ-alumina as the carrier, and the copper-based catalyst loaded with copper ions, can increase the loading rate of copper ions and the catalytic activity of the copper-based catalyst.

[0043] (4) The method for preparing 1-methoxy-2-propanone by fluidized bed, which uses spherical γ-alumina with a specific surface area of 120-150 m 2 / g as the carrier, has high porosity, can increase the loading rate of copper ions and the catalytic activity of the copper-based catalyst.

[0044] (5) The method for preparing 1-methoxy-2-propanone by fluidized bed, which obtains the copper-based catalyst with a small particle size of 20-120 μm, can flow in the fluidized bed reactor for reaction, and the process of discharging, supplementing and replacing the catalyst is convenient. BRIEF DESCRIPTION OF DRAWINGS

[0045] Figure 1 The schematic diagram of the fluidized bed device for Example 1.

[0046] In the figure: 1. Reaction gas inlet; 2. Gas distributor; 3. Lift pipe reactor; 4. Cyclone separator; 5. Reaction gas outlet; 6. Precision filter; 7. Vertical section of downcomer; 8. Deactivated catalyst discharge outlet; 9. Inclined section of downcomer; 10. Fresh catalyst adding port; 11. U-shaped tube heater. DETAILED DESCRIPTION

[0047] The structure of the fluidized bed device is shown in Figure 1 :

[0048] A method for preparing 1-methoxy-2-propanone by fluidized bed, comprising the following steps:

[0049] S1 air enters the lift pipe reactor 3 from the reaction gas inlet 1 through the gas distributor 2, and 1-methoxy-2-propanol enters the preheating U-shaped tube heater 11 from the fresh catalyst adding port 10, and the catalyst enters the lift pipe reactor 3 of the fluidized bed from the fresh catalyst adding port 10;

[0050] S2 control the pressure and temperature of the lift pipe reactor 3, 1-methoxy-2-propanol is catalytically reacted with the catalyst to generate 1-methoxy-2-propanone and hydrogen, and a liquid phase mixture of 1-methoxy-2-propanone and 1-methoxy-2-propanol and hydrogen is obtained;

[0051] S3 separates the liquid phase mixture obtained in step S2 and hydrogen gas through cyclone 4, the hydrogen gas is filtered through precision filter 6 and then discharged from reaction gas outlet 5, the liquid phase mixture is separated by rectification, 1-methoxy-2-propanol is taken out through vertical section 7 of downcomer and inclined section 9 of downcomer to continue reaction in riser reactor 3, and 1-methoxy-2-propanone is taken out;

[0052] S4 the non-inactivated part of the catalyst after reaction in step S2 is passed through vertical section 7 of downcomer and inclined section 9 of downcomer to continue reaction in riser reactor 3, the inactivated catalyst is discharged from inactivated catalyst discharge outlet 8, then fresh catalyst is added through fresh catalyst addition port 10 to continue reaction, thereby realizing online partial replacement of catalyst and stabilizing production.

[0053] The riser reactor contains U-shaped tube heater 11, and the heating medium is heat conducting oil. The inner diameter of the riser reactor is 89 mm, and the height of the riser reactor is 1500 mm.

[0054] The preheating temperature of step S1 is 150℃.

[0055] The reaction temperature of step S2 is 270℃.

[0056] The reaction pressure of step S2 is 0.05 MPa.

[0057] The residence time of the catalyst is 0.05 h.

[0058] The catalyst is a copper-based catalyst, and the copper-based catalyst is an alumina-supported copper-based catalyst.

[0059] The preparation method of the copper-based catalyst comprises the following steps:

[0060] M1 configures a copper nitrate aqueous solution;

[0061] M2 impregnates the alumina into the copper nitrate aqueous solution for 5 h, takes out and dries at 120℃ for 5 h, and calcines at 400℃ for 12 h to obtain a copper-based catalyst.

[0062] The mass concentration of the copper nitrate aqueous solution is 25 wt%.

[0063] The volume ratio of the alumina to the copper nitrate aqueous solution is 1:2.

[0064] The alumina (Al2O3) is spherical γ-alumina, the particle size of the spherical γ-alumina is 70 μm, and the specific surface area is 120-150 m 2 / g, which is purchased from Yangzhou Zhongtianli New Material Co., Ltd.

[0065] Example 2

[0066] A process for the preparation of 1-methoxy-2-propanone in a fluidized bed, according to the embodiment of example 1, except that the reaction temperature of step S2 is 200°C.

[0067] Example 3

[0068] A process for the preparation of 1-methoxy-2-propanone in a fluidized bed, according to the embodiment of example 1, except that the reaction temperature of step S2 is 300°C.

[0069] Performance test

[0070] The one-pass conversion of 1-methoxy-2-propanol and the selectivity of 1-methoxy-2-propanone were tested after 72h continuous reaction according to the embodiments of examples 1-3. The test results are shown in Table 1.

[0071] One-pass conversion = (amount of raw material participating in the reaction / total amount of raw material entering the reactor) x 100%

[0072] Selectivity = (mass of target product / mass of all products) x 100%

[0073] Table 1

[0074] 1-methoxy-2-propanol single pass conversion / % 1-methoxy-2-propanol selectivity / % Example 1 43 99.3 Example 2 16 99.5 Example 3 46 92

[0075] Conclusion: The reaction temperature of example 2 is increased, the one-pass conversion is increased, the selectivity of 1-methoxy-2-propanone is slightly increased, but the device productivity is decreased and the energy consumption is increased. The reaction temperature of example 3 is low, the one-pass conversion is increased, but the selectivity of 1-methoxy-2-propanone is sharply decreased and 1-methoxy-2-propanone is decomposed.

Claims

1. A method for preparing 1-methoxy-2-propanone in a fluidized bed, characterized in that, Includes the following steps: S1 adds the catalyst to the riser reactor of the fluidized bed and preheats it by introducing 1-methoxy-2-propanol; S2 controls the pressure, temperature, and catalytic reaction of the riser reactor to obtain a liquid mixture of 1-methoxy-2-propanone and 1-methoxy-2-propanol; S3 separates the liquid mixture obtained in step S2 by distillation, 1-methoxy-2-propanol is returned to the riser reactor to continue the reaction, and 1-methoxy-2-propanone is collected; The undeactivated portion of the catalyst after step S2 is returned to the riser reactor to continue the reaction. The deactivated catalyst is discharged from the outlet, and then catalyst is added to continue the reaction.

2. The method for preparing 1-methoxy-2-propanone in a fluidized bed according to claim 1, characterized in that, The preheating temperature in step S1 is 150-180℃.

3. The method for preparing 1-methoxy-2-propanone in a fluidized bed according to claim 1, characterized in that, The reaction temperature in step S2 is 200-280℃.

4. The method for preparing 1-methoxy-2-propanone in a fluidized bed according to claim 1, characterized in that, The reaction pressure in step S2 is 0.05-0.1 MPa.

5. The method for preparing 1-methoxy-2-propanone in a fluidized bed according to claim 1, characterized in that, The residence time of the catalyst is 0.02-0.07 h.

6. The method for preparing 1-methoxy-2-propanone in a fluidized bed according to claim 1, characterized in that, The catalyst is a copper-based catalyst, specifically a copper-based catalyst supported on alumina.

7. The method for preparing 1-methoxy-2-propanone in a fluidized bed according to claim 6, characterized in that, The preparation method of the copper-based catalyst includes the following steps: M1 is used to prepare an aqueous solution of copper nitrate; M2 is prepared by immersing alumina in an aqueous solution of copper nitrate for 3-8 hours, removing it, drying it at 100-150℃ for 3-8 hours, and calcining it at 350-450℃ for 10-15 hours to obtain a copper-based catalyst.

8. The method for preparing 1-methoxy-2-propanone in a fluidized bed according to claim 7, characterized in that, The mass concentration of the copper nitrate aqueous solution is 20-30 wt%.

9. The method for preparing 1-methoxy-2-propanone in a fluidized bed according to claim 7, characterized in that, The alumina is spherical γ-alumina with a particle size of 20-120 μm and a specific surface area of ​​120-150 m². 2 / g.

10. The application of a method for preparing 1-methoxy-2-propanone by fluidized bed according to any one of claims 1-9, characterized in that, It is used in the continuous preparation of 1-methoxy-2-propanone.

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