Process method for producing 3-pentanone by dehydrogenation of 3-pentanol

Abstract

The invention belongs to the technical field of fine chemical engineering, and particularly relates to a process method for producing 3-pentanone by dehydrogenation of 3-pentanol. According to the method, 3-pentanol is used as a raw material, a supported copper-based catalyst is used, 3-pentanol is fed into a dehydrogenation reactor for dehydrogenation reaction, 3-pentanol reaction liquid is subjected to continuous rectification, light components are removed in a light component removal tower, and high-purity 3-pentanone is obtained at the top of the heavy component removal tower. The specific catalyst is adopted for preparing the 3-pentanone through dehydrogenation of the 3-pentanol, so that the dehydrogenation efficiency of the 3-pentanol is remarkably improved, and the selectivity of the 3-pentanone is 99.5% or above, so that the single-pass preparation of the 3-pentanone from the 3-pentanol is remarkably improved, and meanwhile, the production energy consumption cost is greatly reduced. According to the method, normal-pressure multi-tower continuous rectification is adopted, separation and purification of the product are achieved, and the 3-pentanone product meeting the standard is obtained.

Description

Technical Field

[0001] The present invention belongs to the technical field of fine chemical industry, and particularly relates to a process for producing 3-pentanone by dehydrogenation of 3-pentanol. Background Art

[0002] 3-Pentanone is a colorless transparent liquid with the molecular formula C 5 H 10 O and the English name 3-Pentanone. Its boiling point is 101 °C, flash point is 12.8 °C, and freezing point is -42 °C. The density is 0.796 g / cm 3 , refractive index 1.392 (20 °C). It is slightly soluble in water, miscible with ethanol and ether, and soluble in acetone. As an important fine chemical raw material and high-grade solvent, it is widely used in industries such as synthetic dyes, pharmaceuticals, and agriculture. 3-Pentanone is a key intermediate in the production of the pesticide herbicide pendimethalin and the anti-avian influenza drug Tamiflu, and its consumption increases year by year, having high economic value.

[0003] There are few global manufacturers of 3-pentanone. Abroad, they are mainly BASF and Caffaro Industrie S.P.A. in Italy. The 3-pentanone produced by BASF is mainly for supporting the production of its downstream pesticide products. The global output of 3-pentanone in 2023 was approximately 25,000 tons. The main industrial use of 3-pentanone is to produce the new selective herbicide pendimethalin, and it can also be used as the production raw material for the medicine oseltamivir (the anti-influenza drug Tamiflu). Pendimethalin is one of the world's best-selling selective herbicides and the tenth largest herbicide in the world. China actively responds to the global management measures for the prohibition and restriction of highly toxic and high-risk pesticides. Relevant competent departments have successively issued a number of announcements on the prohibition and restriction of pesticide use over the years, accelerating the elimination of highly toxic, highly toxic, and high-residue pesticides, and the pesticides are developing towards high efficiency, low toxicity, low residue, high biological activity, and high selectivity.

[0004] The 3-pentanone product can be used for the anti-influenza drug Tamiflu (oseltamivir). In recent years, with the improvement of people's living standards and the increasing attention to their own health, as well as the increasing annual medical and health expenditures, as the world's largest producer and exporter of pharmaceutical intermediates, the domestic and foreign demands jointly drive the continuous expansion of the market scale of pharmaceutical intermediates. The stable development of China's pharmaceutical industry has laid a good foundation for the growth of demand for related pharmaceutical intermediates and upstream chemical raw materials, promoting the growth of 3-pentanone consumption in the pharmaceutical field. In recent years, due to the development of the downstream environmentally friendly pesticide industry and the increasing market application of the anti-influenza drug Tamiflu (oseltamivir), the demand for the 3-pentanone industry has increased significantly, and the product supply has become tight.

[0005] Due to the irritation of 3-pentanone, its preparation is difficult and the production technology content is relatively high. At present, the main production method of 3-pentanone is the synthesis method, including acid synthesis method, acid-aldehyde method, isoprene method, methyl ethyl ketone methanol method, etc. Acid synthesis method: One or two different acids are used under appropriate temperature and catalyst to obtain aliphatic ketones with high conversion rate and selectivity, and then pure products are obtained through separation. This method currently has mature production technology, continuous and large-scale production, but has disadvantages such as too high reaction temperature, high energy consumption, large pollution, and strong equipment corrosion. Acid-aldehyde method: The raw material acid, aldehyde, and water are mixed in a certain proportion and preheated to a certain temperature, then introduced into the reaction section and reacted at 400 - 500 °C. After the reactor is condensed, a mixed ketone is obtained, and pure products are obtained through separation. This process is simple and can be continuously produced, but has low conversion rate, relatively cumbersome catalyst production, and relatively immature production technology. Isoprene method: Mainly, isoprene and water are reacted under specific temperature and pressure conditions with a modified molecular sieve as a catalyst, and then the finished product is obtained through rectification and other methods. This process is simple, but has disadvantages such as high reaction pressure, low product purity, and poor economic benefits. Methyl ethyl ketone methanol method: Methyl ethyl ketone and methanol are reacted at 350 - 500 °C in a certain proportion, and then pure products are obtained through separation. This method has low conversion rate and relatively immature production technology.

[0006] The production of 3-pentanone mainly depends on the selected catalyst and its process. When 3-pentanol is dehydrogenated to produce 3-pentanone, oligomerization or polymerization reactions will occur individually or mutually under the dehydrogenation reaction conditions. Generally, the catalyst will gradually lose its activity due to the accumulation of oligomers or polymers on the catalyst surface and coking of the catalyst.

[0007] The traditional preparation process of copper-based catalysts has disadvantages such as difficulty in precisely controlling the composition of the finished catalyst, low dispersion of Cu, weak interaction between Cu and the carrier when the Cu content is high; moreover, the Tammann temperature of Cu is relatively low, and it is easy to agglomerate and deactivate at high temperatures.

[0008] Therefore, based on this, we propose a process method for dehydrogenating 3-pentanol to produce 3-pentanone, hoping to solve the deficiencies in the existing technology. Summary of the Invention

[0009] The purpose of the present invention is to provide a process method for dehydrogenating 3-pentanol to produce 3-pentanone in view of the existing problems.

[0010] The present invention is achieved through the following technical solutions:

[0011] A process method for dehydrogenating 3-pentanol to produce 3-pentanone includes the following steps:

[0012] S1. The material is pumped from the 3-pentanol dehydrogenation buffer tank to the heat exchanger after being metered by the deacidifier and flowmeter, heated to 240 - 290 °C, and then enters the dehydrogenation reactor for dehydrogenation reaction;

[0013] S2. The 3-pentanone mixture obtained after the dehydrogenation reaction is cooled to 40 °C in the heat exchanger. The cooled 3-pentanone mixture enters the gas-liquid separator, and the liquid-phase material is pumped to the 3-pentanone light component removal tower to remove light components;

[0014] S3. The material at the bottom of the 3-pentanone light component removal tower is pumped to the 3-pentanone rectification tower to remove heavy components, and the material at the top of the tower is the 3-pentanone product;

[0015] S4. The material at the bottom of the 3-pentanone rectification tower is pumped to the 3-pentanol rectification tower to remove heavy components, and the material at the top of the tower is 3-pentanol, which is pumped to the 3-pentanol dehydrogenation buffer tank for recycling.

[0016] Further preferably, the catalyst used in the dehydrogenation reaction in step S1 is a supported copper-based catalyst.

[0017] Further preferably, the preparation of the supported copper-based catalyst includes the following steps:

[0018] (1) Dissolve Cu(NO 3 ) 2 ·3H 2 O in deionized water. After it is completely dissolved, add ammonia water and stir at 300 - 400 rpm for 30 - 40 min to obtain a copper ammonia solution;

[0019] (2) Add silica and titanium dioxide to the bead mill in a ratio of 10 - 12:1, grind the mixture at 3000 - 4000 rpm for 10 - 15 min, and set aside the mixture;

[0020] (3) Add the mixture obtained in step (2) to a round-bottom flask, then add the salicylic acid-ethanol solution to the round-bottom flask. After stirring and mixing evenly at 200 - 300 rpm, add the ethylenediamine-ethanol solution dropwise to the round-bottom flask, continue stirring for 10 - 16 h, then under the N 2 atmosphere, reflux at 70 - 80 °C for 1 - 2 h, then let it stand and cool to room temperature, wash it 3 - 4 times with anhydrous ethanol by centrifugation, place it in anhydrous ethanol for recrystallization, and then place it in a vacuum drying oven and dry it to constant weight at a temperature of 40 - 50 °C to obtain the catalyst support for standby;

[0021] (4) Add the catalyst support obtained in step (3) to the copper ammonia solution in step (1). Under ultrasonic conditions, stir at 400 - 500 rpm for 2 - 3 h, then place it in a constant temperature water bath for ammonia evaporation treatment. After evaporating ammonia until neutral, wash it 3 - 5 times with deionized water, then place it in a vacuum drying oven and dry it at 40 - 50 °C to constant weight. Then place it in a muffle furnace and calcine it at 400 - 500 °C for 3 - 4 h. Finally, place the obtained sample in a 10% H 2 / N 2 mixed gas and raise the temperature to 300 °C at a rate of 5 °C / min and hold for 2 h to obtain the supported copper-based catalyst.

[0022] Further preferably, the weight-to-volume ratio of Cu(NO 3 ) 2 ·3H 2 O to deionized water in step (1) is 0.35 - 0.4 g:50 mL.

[0023] Further preferably, the mass ratio of the mixture, salicylic acid, and ethylenediamine in step (3) is 4 - 5:4 - 4.5:1.

[0024] Further preferably, the mass-to-volume ratio of the catalyst support to the copper ammonia solution in step (4) is 1 g:30 - 40 mL.

[0025] Further preferably, the temperature is controlled at 160 - 250 °C, the space velocity is 0.6 - 1.4 h -1 during the dehydrogenation reaction in step S1, and the pressure is 0 - 0.3 MPa.

[0026] Further preferably, the top pressure of the light removal tower is 0.01 - 0.05 MPa, the bottom temperature is 105 - 130 °C, and the top temperature is 100 - 120 °C.

[0027] Further preferably, the top pressure of the 3-pentanone distillation column is -0.06 - -0.01 MPa, the bottom temperature is 100 - 120 °C, and the top temperature is 75 - 90 °C.

[0028] Further preferably, the top pressure of the 3-pentanol distillation column is 0.01 - 0.05 MPa, the bottom temperature is 135 - 160 °C, and the top temperature is 115 - 130 °C.

[0029] Further preferably, the reaction process of producing 3-pentanone by dehydrogenating 3-pentanol is as follows:

[0030]

[0031] The present invention has the following advantages compared with the prior art:

[0032] The present invention uses 3-pentanol as a raw material and a supported copper-based catalyst. The 3-pentanol is fed into a dehydrogenation reactor for dehydrogenation reaction. The 3-pentanol reaction solution is subjected to continuous rectification. The light components are removed in the light component removal tower, and high-purity 3-pentanone is obtained at the top of the heavy component removal tower.

[0033] The dehydrogenation of 3-pentanol to prepare 3-pentanone in the present invention uses a specific catalyst, which significantly improves the dehydrogenation efficiency of 3-pentanol, and the selectivity of 3-pentanone is above 99.5%. Therefore, the one-pass preparation of 3-pentanone from 3-pentanol is significantly improved, and at the same time, the production energy consumption cost is greatly reduced.

[0034] The present invention adopts atmospheric pressure multi-column continuous rectification to realize the separation and purification of products, and obtains 3-pentanone products that meet the standards. Brief Description of the Drawings

[0035] Figure 1 is a process flow chart for the dehydrogenation of 3-pentanol to produce 3-pentanone in the present invention;

[0036] Figure 2 is a curve graph showing the relationship between the saturated vapor pressure and temperature of 3-pentanol;

[0037] Figure 3 is a DSC test curve graph of the catalyst. Detailed Embodiments

[0038] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0039] Example 1

[0040] A process method for the dehydrogenation of 3-pentanol to produce 3-pentanone includes the following steps:

[0041] S1. The material is pumped from the 3-pentanol dehydrogenation buffer tank through an acid remover and a flow meter, heated to 240 °C in a heat exchanger, and then enters a dehydrogenation reactor for dehydrogenation reaction. The reaction temperature is controlled at 160 °C, the space velocity is 0.6 h -1 , and the pressure is 0 MPa;

[0042] S2. The 3-pentanone mixture obtained after the dehydrogenation reaction is cooled to 40 °C in a heat exchanger. The cooled 3-pentanone mixture enters a gas-liquid separator, and the liquid-phase material is pumped to a 3-pentanone light component removal tower to remove light components;

[0043] The top pressure of the light component removal tower is 0.01 MPa, the bottom temperature of the tower is 105 °C, and the top temperature of the tower is 100 °C;

[0044] S3. The bottom material pump of the 3-pentanone light component removal column pumps the bottom material to the 3-pentanone rectification column to remove the heavy components, and the top material is the 3-pentanone product;

[0045] The top pressure of the 3-pentanone rectification column is -0.06 MPa, the bottom temperature is 100 °C, and the top temperature is 75 °C;

[0046] S4. The bottom material pump of the 3-pentanone rectification column pumps the bottom material to the 3-pentanol rectification column to remove the heavy components, the top material is 3-pentanol, and it is pumped to the 3-pentanol dehydrogenation buffer tank for circulation;

[0047] The top pressure of the 3-pentanol rectification column is 0.01 MPa, the bottom temperature is 135 °C, and the top temperature is 115 °C.

[0048] The catalyst used in the dehydrogenation reaction described in step S1 is a supported copper-based catalyst.

[0049] The preparation of the supported copper-based catalyst includes the following steps:

[0050] (1) Dissolve Cu(NO 3 ) 2 ·3H 2 O in deionized water. The weight-volume ratio of Cu(NO 3 ) 2 ·3H 2 O to deionized water is 0.35 g:50 mL. After it is completely dissolved, add ammonia water dropwise and stir at 300 rpm for 30 min to obtain a copper ammonia solution;

[0051] (2) Add silica and titanium dioxide to the bead mill in a ratio of 10:1, and grind the mixture at 3000 rpm for 10 min for later use;

[0052] (3) Add the mixture obtained in step (2) to a round-bottom flask, then add the salicylic acid-ethanol solution to the round-bottom flask. After stirring and mixing evenly at 200 rpm, add the ethylenediamine-ethanol solution dropwise to the round-bottom flask, continue stirring for 10 h, and then reflux at 70 °C for 1 h under an N 2 atmosphere. Then let it stand and cool to room temperature, wash it 3 times by centrifugation with absolute ethanol, perform recrystallization in absolute ethanol, and then place it in a vacuum drying oven and dry it to constant weight at 40 °C to obtain the catalyst support for later use;

[0053] The mass ratio of the mixture, salicylic acid, and ethylenediamine is 4:4:1;

[0054] (4) Add the catalyst support obtained in step (3) to the copper ammonia solution in step (1). The mass-volume ratio of the catalyst support to the copper ammonia solution is 1 g:30 mL. Under ultrasonic conditions, stir at 400 rpm for 2 h, then place it in a constant temperature water bath for ammonia evaporation treatment. After the ammonia evaporation reaches neutrality, wash it 3 times with deionized water, then place it in a vacuum drying oven and dry it at 40 °C to constant weight. Then place it in a muffle furnace and calcine it at 400 °C for 3 h. Finally, place the obtained sample in 10% H 2 / N 2 The mixed gas is heated to 300 °C at a rate of 5 °C / min and held for 2 h to obtain the supported copper-based catalyst.

[0055] Example 2

[0056] A process for producing 3-pentanone by dehydrogenation of 3-pentanol includes the following steps:

[0057] S1. The material is pumped from the 3-pentanol dehydrogenation buffer tank through the deacidifier and flowmeter, then pumped to the heat exchanger. After heating to 260 °C, it enters the dehydrogenation reactor for dehydrogenation reaction. Control the reaction temperature at 200 °C and the space velocity at 1 h -1 , and the pressure at 1.15 MPa;

[0058] S2. The 3-pentanone mixture obtained after the dehydrogenation reaction is cooled to 40 °C through the heat exchanger. The cooled 3-pentanone mixture enters the gas-liquid separator, and the liquid-phase material is pumped to the 3-pentanone light-component removal tower to remove the light components;

[0059] The top pressure of the light-component removal tower is 0.03 MPa, the bottom temperature is 115 °C, and the top temperature is 110 °C;

[0060] S3. The material at the bottom of the 3-pentanone light-component removal tower is pumped to the 3-pentanone rectification tower to remove the heavy components, and the material at the top is the 3-pentanone product;

[0061] The top pressure of the 3-pentanone rectification tower is -0.03 MPa, the bottom temperature is 110 °C, and the top temperature is 83 °C;

[0062] S4. The material at the bottom of the 3-pentanone rectification tower is pumped to the 3-pentanol rectification tower to remove the heavy components, and the material at the top is 3-pentanol, which is pumped to the 3-pentanol dehydrogenation buffer tank for recycling;

[0063] The top pressure of the 3-pentanol rectification tower is 0.03 MPa, the bottom temperature is 148 °C, and the top temperature is 122 °C.

[0064] The catalyst used in the dehydrogenation reaction in step S1 is a supported copper-based catalyst.

[0065] The preparation of the supported copper-based catalyst includes the following steps:

[0066] (1) Dissolve Cu(NO 3 ) 2 ·3H 2 O in deionized water. The weight - volume ratio of Cu(NO 3 ) 2 ·3H 2 O to deionized water is 0.38 g:50 mL. After it is completely dissolved, add ammonia water dropwise and stir at 350 rpm for 35 min to obtain a copper - ammonia solution;

[0067] (2) Add silica and titanium dioxide to a bead mill in a ratio of 11:1, and grind the mixture at 3500 rpm for 13 min for later use;

[0068] (3) Add the mixture obtained in step (2) to a round - bottom flask, then add a salicylic acid - ethanol solution to the round - bottom flask. After stirring and mixing evenly at 250 rpm, add an ethylenediamine - ethanol solution dropwise to the round - bottom flask. Continue stirring for 13 h, then under a N 2 atmosphere, reflux at 75 °C for 1.5 h, then let it stand and cool to room temperature. Wash it 3 times by centrifugation with absolute ethanol and then perform recrystallization in absolute ethanol. Then place it in a vacuum drying oven and dry it to constant weight at 45 °C to obtain a catalyst support for later use;

[0069] The mass ratio of the mixture, salicylic acid, and ethylenediamine is 4.5:4.3:1;

[0070] (4) Add the catalyst support obtained in step (3) to the copper - ammonia solution in step (1). The mass - volume ratio of the catalyst support to the copper - ammonia solution is 1 g:35 mL. Under ultrasonic conditions, stir at 450 rpm for 2.5 h, then place it in a constant - temperature water bath for ammonia evaporation treatment. After evaporating ammonia until neutral, wash it 4 times with deionized water, then place it in a vacuum drying oven and dry it to constant weight at 45 °C. Then place it in a muffle furnace and calcine it at 450 °C for 3.5 h. Finally, place the obtained sample in a 10% H 2 / N 2 mixed gas and raise the temperature to 300 °C at a rate of 5 °C / min and hold for 2 h to obtain a supported copper - based catalyst.

[0071] Example 3

[0072] A process for producing 3 - pentanone by dehydrogenation of 3 - pentanol includes the following steps:

[0073] S1. The material is pumped from a 3 - pentanol dehydrogenation buffer tank through a deacidifier and a flowmeter, metered, and then pumped to a heat exchanger. After heating to 290 °C, it enters a dehydrogenation reactor for dehydrogenation reaction. Control the reaction temperature at 250 °C, the space velocity at 1.4 h -1 , and the pressure at 0.3 MPa;

[0074] S2. The 3-pentanone mixture obtained after the dehydrogenation reaction is cooled to 40°C through a heat exchanger. The cooled 3-pentanone mixture enters a gas-liquid separator, and the liquid-phase material is pumped to a 3-pentanone light-component removal tower to remove light components.

[0075] The top pressure of the light-component removal tower is 0.05 MPa, the bottom temperature is 130°C, and the top temperature is 120°C.

[0076] S3. The bottom material of the 3-pentanone light-component removal tower is pumped to a 3-pentanone rectification tower to remove heavy components, and the top material is the 3-pentanone product.

[0077] The top pressure of the 3-pentanone rectification tower is -0.01 MPa, the bottom temperature is 120°C, and the top temperature is 90°C.

[0078] S4. The bottom material of the 3-pentanone rectification tower is pumped to a 3-pentanol rectification tower to remove heavy components, and the top material is 3-pentanol, which is pumped to a 3-pentanol dehydrogenation buffer tank for circulation.

[0079] The top pressure of the 3-pentanol rectification tower is 0.05 MPa, the bottom temperature is 160°C, and the top temperature is 130°C.

[0080] The catalyst used in the dehydrogenation reaction described in step S1 is a supported copper-based catalyst.

[0081] The preparation of the supported copper-based catalyst includes the following steps:

[0082] (1) Dissolve Cu(NO 3 ) 2 ·3H 2 O in deionized water. The weight-volume ratio of Cu(NO 3 ) 2 ·3H 2 O to deionized water is 0.4 g:50 mL. After it is completely dissolved, add ammonia water dropwise and stir at 400 rpm for 40 min to obtain a copper-ammonia solution.

[0083] (2) Add silica and titanium dioxide to a bead mill in a ratio of 12:1, and grind the mixture at 4000 rpm for 15 min for later use.

[0084] (3) Add the mixture obtained in step (2) to a round-bottom flask, then add a salicylic acid-ethanol solution to the round-bottom flask. After stirring and mixing evenly at 300 rpm, add an ethylenediamine-ethanol solution dropwise to the round-bottom flask, continue stirring for 16 h, then reflux at 80°C for 2 h under an N 2 atmosphere, and then let it stand and cool to room temperature. Centrifuge and wash it 4 times with absolute ethanol, then perform recrystallization in absolute ethanol, and then place it in a vacuum drying oven and dry it to constant weight at 50°C to obtain the catalyst support for later use.

[0085] The mass ratio of the mixture, salicylic acid, and ethylenediamine is 5:4.5:1;

[0086] (4) Add the catalyst support obtained in step (3) to the copper ammonia solution in step (1). The mass-volume ratio of the catalyst support to the copper ammonia solution is 1 g:40 mL. Under ultrasonic conditions, stir at 500 rpm for 3 h, then place it in a constant temperature water bath for ammonia evaporation treatment. After evaporating ammonia until neutral, wash it 5 times with deionized water, then place it in a vacuum drying oven and dry it at 50 °C to constant weight. Then place it in a muffle furnace and calcine it at 500 °C for 4 h. Finally, place the obtained sample in 10% H 2 / N 2 The mixed gas is heated to 300 °C at a rate of 5 °C / min and held for 2 h to obtain the supported copper-based catalyst.

[0087] All sample analyses were performed using a Shimadzu GC-2010pro gas chromatograph equipped with an FID detector; an HP-1 (60 m × 250 μm × 1 μm) quartz capillary column. The column temperature was 35 °C and held for 15 min, then increased to 130 °C at a rate of 10 °C / min and held for 0 min, then increased to 230 °C at a rate of 20 °C / min and held for 15 minutes; the carrier gas (N 2 ) flow rate was 30 mL / min; the vaporization temperature was 220 °C; the detector temperature was 230 °C; the split ratio was 49:1; the quantification method: area normalization method.

[0088] Optimization Study on the Dehydrogenation Process of 3-Pentanol

[0089] 1.1 Temperature

[0090] Temperature is one of the key conditions affecting the dehydrogenation of 3-pentanol. The appropriate temperature is the comprehensive balance result of reaction rate, equilibrium conversion, selectivity, catalyst service life, and reaction phase state. The relationship between the saturated vapor pressure of 3-pentanol and temperature is as Figure 2 shown.

[0091] 150 g of the dehydrogenation catalyst, with a mass space velocity of 0.8 h -1 , under the condition of normal pressure, investigate the influence of temperature on the dehydrogenation reaction of 3-pentanol. The results are shown in Table 1.

[0092] Table 1 Influence of Temperature on the Dehydrogenation Reaction of 3-Pentanol

[0093]

[0094]

[0095] As can be seen from Table 1 above, as the temperature rises, the conversion rate of 3-pentanol gradually increases, from 47.90% to 87.81%. When the reaction temperature reaches 240 °C, while the conversion rate increases, the selectivity is above 99.5%, showing good selectivity. As the temperature rises, side reactions occur slowly and by-products are generated. Considering the dehydrogenation reaction effect and the influence of the dehydrogenation catalyst comprehensively, the temperature is preferably 190 - 240 °C.

[0096] 1.2 Weight hourly space velocity

[0097] Under the conditions of 150 g (100 mL) of the dehydrogenation catalyst, a reaction temperature of 240 °C, and atmospheric pressure, the influence of the space velocity on the dehydrogenation reaction of 3-pentanol was investigated, and the results are shown in Table 2.

[0098] Table 2 Conversion rate and selectivity of 3-pentanol dehydrogenation reaction at different space velocities

[0099] Serial number <![CDATA[airspeed / h -1 > Conversion rate of 3-pentanol / % Selectivity of 3-pentanone / % 1 0.6 84.73 99.41 2 0.8 84.18 99.56 3 1.0 79.41 99.58 4 1.2 75.99 99.63 5 1.4 68.18 99.69

[0100] As can be seen from Table 2 above, as the space velocity rises, the conversion rate of 3-pentanol gradually decreases. When the space velocity reaches 1.2 h -1 , the conversion rate of 3-pentanol is still above 70%. The selectivity shows the opposite trend. As the space velocity increases, the selectivity of 3-pentanone gradually rises, and the by-products gradually decrease.

[0101] 1.3 Pressure

[0102] With 150 g of the dehydrogenation catalyst, a reaction temperature of 240 °C, and a space velocity of 0.8 h -1 , the influence of pressure on the dehydrogenation reaction of 3-pentanol was investigated, and the results are shown in Table 3.

[0103] Table 3 Conversion rate and selectivity of 3-pentanol dehydrogenation reaction at different pressures

[0104] Serial number Pressure / MPa Conversion rate of 3-pentanol / % Selectivity of 3-pentanone / % 1 0 88.18 99.56 2 0.1 79.50 99.61 3 0.2 76.68 99.66 4 0.3 65.79 99.70

[0105] As can be seen from Table 3 above, as the pressure increases, the conversion rate of 3-pentanol decreases significantly. When the pressure reaches 0.2 MPa, the conversion rate of 3-pentanol is 76.68%, and the selectivity is above 99.5%. When the pressure reaches 0.3 MPa, the conversion rate of 3-pentanol decreases significantly, dropping to 65.79%.

[0106] In this experiment, a dehydrogenation catalyst (supported copper-based catalyst) was used to conduct a dehydrogenation experiment on 3-pentanol, aiming to prepare 3-pentanone by gas-phase dehydrogenation of 3-pentanol and verify the reaction activity of the catalyst. The experimental device adopted an adiabatic bed reaction, and the feeding method was from top to bottom. The catalyst was filled in the dry basis, with a filling mass of 150 g and a filling height of 24 cm. During the experiment, the effects of changing reaction temperature, mass space velocity, reaction pressure and other conditions on the dehydrogenation reaction of 3-pentanol were investigated to determine the appropriate process conditions. Combining the experimental data, it can be seen that when the bed temperature is 190-240 °C, the experimental pressure is 0-0.2 MPa, and the mass space velocity is 0.8-1.2 h -1 Under the conditions of, the conversion rate of 3-pentanol is about 70%, and the selectivity of 3-pentanone is above 99.5%.

[0107] 2. Light and heavy removal unit

[0108] 2.1 Light removal unit

[0109] The 3-pentanone mixed material obtained from the dehydrogenation reaction was added to the dehydrogenation rectification column for atmospheric pressure batch rectification. The bottom temperature of the column was controlled at 105-130 °C, the top temperature of the column was controlled at 100-120 °C, and the top pressure of the column was controlled at 0.01-0.05 MPa to remove the light components in the 3-pentanone mixed material. The crude 3-pentanone obtained at the bottom of the column was subjected to the next heavy removal rectification. The specific experimental results are shown in Table 4 below.

[0110] Table 4 3-Pentanone light removal data

[0111] Batch 3-Pentanol (%) 3-Pentanone (%) Light components (%) Heavy components (%) Raw material 30.46 68.73 0.62 0.19 Top product 0.39 82.60 17.01 / Bottom product 30.77 68.59 0.13 0.51

[0112] 2.2 3-Pentanone rectification

[0113] The crude 3-pentanol material after heavy removal treatment was added to the 3-pentanone rectification column for atmospheric pressure batch rectification. The bottom temperature of the column was controlled at 100-120 °C, the top temperature of the column was controlled at 75-90 °C, and the top pressure of the column was controlled at -0.06 - -0.01 MPa. The 3-pentanone product was obtained at the top of the column, and the bottom discharge was sent for the next step of 3-pentanol purification. The specific experimental results are shown in Table 5 below.

[0114] Table 5 3-Pentanone data

[0115] Batch 3-Pentanol (%) 3-Pentanone (%) Light components (%) Heavy components (%) Raw material 30.77 68.59 0.13 0.51 Top product / 99.80 0.08 0.12 Bottom product 97.64 0.04 / 2.32

[0116] 2.3 3-Pentanol purification

[0117] Add the above-mentioned bottom materials to a 3-pentanol rectification column and perform atmospheric batch rectification. Control the bottom temperature at 135 - 160 °C, the top temperature at 115 - 130 °C, and the top pressure at 0.01 - 0.05 MPa. Remove the heavy components in the 3-pentanol rectification column. The top material is 3-pentanol, which is returned to dehydrogenate 3-pentanol to prepare 3-pentanone. The specific experimental data are shown in Table 6 below.

[0118] Table 6 Data of removing heavy components

[0119] Batch 3-Pentanol (%) 3-Pentanone (%) Light components (%) Heavy components (%) Raw material 97.64 0.04 / 2.32 Top product 99.86 0.05 / 0.09 Bottom product 30.14 / / 69.86

[0120] In summary, the conversion rate of 3-pentanol provided by the present invention reaches more than 70%, and the selectivity of 3-pentanone is as high as about 99.5%.

[0121] 3. Thermal stability test of supported copper-based catalyst The differential scanning calorimetry (DSC) test information and test curves of the supported copper-based catalyst are shown in Table 7 and Figure 3 .

[0123] Table 7 DSC test information of supported copper-based catalyst

[0124]

[0125]

[0126] The DSC test results of the supported copper-based catalyst are shown in Table 8.

[0127] Table 8 DSC test results of supported copper-based catalyst

[0128] Temperature range (°C) Peak temperature (°C) Heat release (J / g) Heat absorption (J / g) 262.1—340.9 305.3 64.0 -

[0129] As can be seen from Table 8 above, the differential scanning calorimetry test results show that there is an obvious exothermic signal at 262.1 °C for the test material, and the sample undergoes exothermic decomposition. In the test range of 262.1 - 340.9 °C, the heat release of the sample is 64.0 J / g.

[0130] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, makes equivalent substitutions or changes, and all should be covered within the protection scope of the present invention.

Claims

1. A process for producing 3-pentanone by dehydrogenation of 3-pentanol, characterized in that: The steps include: S1, the material is pumped from the 3-pentanol dehydrogenation buffer tank to the heat exchanger after being measured by the deacidifier and flow meter, heated to 240-290°C and then enters the dehydrogenation reactor for dehydrogenation reaction; S2, the 3-pentanone mixture obtained after the dehydrogenation reaction is cooled to 40° C. through a heat exchanger, and the cooled 3-pentanone mixture enters a gas-liquid separator, and the liquid phase material is pumped to a 3-pentanone light component removal tower to remove light components; S3, 3-pentanone light removal tower kettle material pump to 3-pentanone distillation tower to remove heavy components, the tower top material is 3-pentanone product; S4. The material from the bottom of the 3-pentanone distillation tower is pumped to the 3-pentanol distillation tower to remove heavy components. The top material is 3-pentanol, which is pumped to the 3-pentanol dehydrogenation buffer tank for circulation.

2. The process for producing 3-pentanone by dehydrogenation of 3-pentanol according to claim 1, characterized in that: The catalyst used in the dehydrogenation reaction in step S1 is a supported copper-based catalyst.

3. The process for producing 3-pentanone by dehydrogenation of 3-pentanol according to claim 2, characterized in that: The preparation of the supported copper-based catalyst comprises the following steps: (1) Dissolve Cu(NO3)2·3H2O in deionized water, add ammonia water dropwise after it is completely dissolved, and stir at 300-400 rpm for 30-40 min to obtain a copper ammonia solution; (2) adding silicon dioxide and titanium dioxide in a ratio of 10-12:1 into a bead mill, grinding the mixture at 3000-4000 rpm for 10-15 min for later use; (3) Add the mixture obtained in step (2) to a round-bottom flask, then add the salicylic acid-ethanol solution to the round-bottom flask, stir and mix at 200-300 rpm, then drop the ethylenediamine-ethanol solution into the round-bottom flask, continue stirring for 10-16 hours, reflux at 70-80° C. for 1-2 hours under N2 atmosphere, then cool to room temperature, wash with anhydrous ethanol by centrifugation 3-4 times, then place in anhydrous ethanol for recrystallization, and then place in a vacuum drying oven at 40-50° C. to dry to constant weight to obtain a catalyst carrier for use; (4) The catalyst carrier obtained in step (3) is added to the copper ammonia solution of step (1), and stirred at 400-500 rpm for 2-3 hours under ultrasonic conditions, and then placed in a constant temperature water bath for ammonia evaporation. After the ammonia is evaporated to neutrality, it is washed with deionized water 3-5 times and placed in a vacuum drying oven at 40-50° C. to dry to constant weight, and then placed in a muffle furnace and calcined at 400-500° C. for 3-4 hours. Finally, the obtained sample is placed in a 10% H2 / N2 mixed gas and the temperature is raised to 300° C. at a rate of 5° C. / min and maintained for 2 hours to obtain a supported copper-based catalyst.

4. The process for producing 3-pentanone by dehydrogenation of 3-pentanol according to claim 3, characterized in that: The weight volume ratio of Cu(NO3)2·3H2O to deionized water in step (1) is 0.35-0.4 g:50 mL.

5. The process for producing 3-pentanone by dehydrogenation of 3-pentanol according to claim 3, characterized in that: The mass ratio of the mixture, salicylic acid and ethylenediamine in step (3) is 4-5:4-4.5:

1.

6. The process for producing 3-pentanone by dehydrogenation of 3-pentanol according to claim 3, characterized in that: The mass volume ratio of the catalyst carrier and the copper ammonia solution described in step (4) is 1g:30-40mL.

7. The process for producing 3-pentanone by dehydrogenation of 3-pentanol according to claim 1, characterized in that: The dehydrogenation reaction in step S1 is carried out at a temperature of 160-250°C and a space velocity of 0.6-1.4h -1 , the pressure is 0-0.3MPa.

8. The process for producing 3-pentanone by dehydrogenation of 3-pentanol according to claim 1, characterized in that: The tower top pressure of the lightness removal tower is 0.01-0.05MPa, the tower bottom temperature is 105-130°C, and the tower top temperature is 100-120°C.

9. The process for producing 3-pentanone by dehydrogenation of 3-pentanol according to claim 1, characterized in that: The top pressure of the 3-pentanone distillation tower is -0.06--0.01MPa, the bottom temperature is 100-120°C, and the top temperature is 75-90°C.

10. The process for producing 3-pentanone by dehydrogenation of 3-pentanol according to claim 1, characterized in that: The top pressure of the 3-pentanol distillation tower is 0.01-0.05 MPa, the bottom temperature is 135-160° C., and the top temperature is 115-130° C.

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