Process method for producing 2-pentanone by dehydrogenation of 2-pentanol

Abstract

The invention belongs to the technical field of fine chemical engineering, and particularly relates to a process method for producing 2-pentanone by dehydrogenation of 2-pentanol. According to the method, 2-pentanol is used as a raw material and is fed into a dehydrogenation reactor in a top-inlet bottom-outlet feeding manner, and a dehydrogenation reaction is performed under the action of a catalyst and an auxiliary agent; the catalyst provided by the invention reduces the reaction energy, promotes the dehydrogenation reaction, improves the purity of 2-pentanone and solves the problem that 2-pentanone gradually loses activity due to coking through the synergistic effect of boron and phosphorus in combination with the graded pore carrier and Fe electronic regulation and control, and the service life is long. The 2-pentanol and the auxiliaries are jointly added into a reaction system and cooperate with each other, the auxiliaries can promote the dehydrogenation reaction of the 2-pentanol and inhibit side reactions, and then the yield and purity of the product are improved. Then the 2-pentanol reaction liquid is subjected to continuous rectification, light components are removed in the light component removal tower, and high-purity 2-pentanone is obtained at the top of the heavy component removal tower, so that the dehydrogenation efficiency of the 2-pentanol is remarkably improved, and meanwhile, the production energy consumption cost is greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of fine chemical engineering, and particularly relates to a process for producing 2-pentanone by dehydrogenation of 2-pentanol. Background Art

[0002] Pentanone (2-pentanone) is a typical biomass molecule. It is a liquid at room temperature, and its liquid color is milky white. 2-Pentanone is a liquid that is insoluble in water and can be applied to organic synthetic materials, the preparation of lubricating oils, resin coatings, extractants, substitutes for diacetyl ketone, etc. It is also called methyl propyl ketone, abbreviated as 2-PE.

[0003] Previously, the main uses of 2-pentanone were as pharmaceutical intermediates and pesticide intermediates, and its production and daily usage were relatively small. Currently, one research direction in renewable energy is liquid fuels. Some ethanol fuels and propanol fuels have gradually been applied to the construction of China's industrial system. However, the production of ethanol biofuels requires a large amount of food crops, which will have a considerable impact on China's food security and guarantee. Biofuels have some excellent characteristics that other fuels do not have, such as being relatively stable and having a higher calorific value. However, ethanol biofuels have limitations such as being volatile. For some new biofuels, they mainly need to have two advantages: one is to have a high energy density value and a small unit volume; the other is to avoid using a large amount of food crops to prevent a food crisis in China and affect people's lives. Compared with the various physical and chemical properties of ethanol and gasoline, 2-pentanone is an excellent liquid biofuel for the current social development and conforms to the concept of current social sustainable development.

[0004] Currently, the main industrial routes for synthesizing 2-pentanone are: dehydrogenation of secondary pentanol, co-heating of ethyl butyrylacetate and water, the corresponding by-products generated during the dehydration of pentanal to produce pentadiene, dry distillation of a mixture of calcium acetate and calcium n-butyrate, etc.

[0005] At present, a new synthesis method is to use the K-CuZrO2 catalyst to catalyze ethanol to prepare 2-pentanone. The team of Wei Ling from the Institute of Coal Chemistry, Chinese Academy of Sciences reported the preparation of 2-pentanone from ethanol. A new type of K-CuZrO2 was prepared by the coprecipitation method using KOH as a precursor and adding it to the ZrO(NO3)2·2H2O and Cu(NO3)2·3H2O solutions. This catalyst has the characteristics of being cheap and easy to obtain. Using this catalyst can not only produce 2-pentanone, but also produce acetaldehyde, acetone, 3-hydroxybutyraldehyde and other substances. The advantage of this method is that a small amount of ethanol can have a high conversion rate, and the selectivity of 2-pentanone is also relatively high. However, with the increase in the reaction amount of ethanol, a large amount of acetaldehyde will be generated, and the dehydrogenated acetaldehyde cannot be condensed to produce 2-pentanone. Therefore, this method is not easy to achieve for large-scale production of 2-pentanone and cannot be industrially produced on a large scale.

[0006] Using Pt / AC can catalyze ethanol and acetone to produce 2-pentanone. The first step is that ethanol dehydrogenates to form acetaldehyde on the Pt / AC catalyst. Acetaldehyde and acetone self-condense to remove one molecule of water and generate 2-pentanone under the reduction of hydrogen addition by the catalyst. The Pt / AC catalyst has high selectivity and conversion rate for catalyzing 2-pentanone. However, the price of Pt metal is relatively expensive, and after multiple uses, the catalyst is prone to carbon deposition and loss of metal active components, and the price of the catalyst is relatively expensive, which is not conducive to large-scale industrial production.

[0007] The production of 2-pentanone mainly depends on the selected catalyst and its process. When 2-pentanol is dehydrogenated to produce 2-pentanone, oligomerization or polymerization reactions will occur among themselves or with each other 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.

[0008] Therefore, based on this, we propose a process method for the dehydrogenation of 2-pentanol to produce 2-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 the dehydrogenation of 2-pentanol to produce 2-pentanone in view of the existing problems.

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

[0011] A process method for the dehydrogenation of 2-pentanol to produce 2-pentanone includes the following steps:

[0012] S1. The raw material is pumped from the 2-pentanol dehydrogenation buffer tank through a deacidifier and a flow meter, metered, and then pumped to a heat exchanger. After being heated to 240-290 °C, it enters the dehydrogenation reactor and undergoes a dehydrogenation reaction under the action of a catalyst and an auxiliary agent;

[0013] S2. After cooling the 2-pentanone mixture obtained through the dehydrogenation reaction to 40 °C in a heat exchanger, the cooled 2-pentanone mixture enters a gas-liquid separator, and the liquid-phase material is pumped to a 2-pentanone light-component removal column to remove light components;

[0014] S3. Pump the bottom material of the 2-pentanone light-component removal column to a 2-pentanone rectification column to remove heavy components, and the overhead material is the 2-pentanone product;

[0015] S4. Pump the bottom material of the 2-pentanone rectification column to a 2-pentanol rectification column to remove heavy components, and the overhead material is 2-pentanol, which is pumped to a 2-pentanol dehydrogenation buffer tank for recycling.

[0016] Furthermore, the addition amount of the catalyst described in step S1 is 1-2% of the substrate mass, and the addition amount of the auxiliary agent is 2-3% of the catalyst mass.

[0017] Furthermore, the preparation of the catalyst described in step S1 includes the following steps:

[0018] (1) Prepare a mixed aqueous solution of ferric nitrate, zinc nitrate, and copper nitrate according to a mass ratio of 1:2-3:6-7. Add polyvinylpyrrolidone to the mixed aqueous solution and ultrasonically disperse for 20-30 min to obtain a mixed solution;

[0019] (2) Add a catalyst carrier to the mixed solution in step (1), load the active components by the equal-volume impregnation method, then dry to constant weight, and then calcine at 350-450 °C for 3-4 h to form a catalyst precursor for standby;

[0020] (3) Immerse the catalyst precursor in an ethanol solution of 0.8-1.2 wt% H3BO3, let it stand for 10-12 h, then dry at 80-90 °C for 3-4 h, then immerse it in an aqueous solution of 0.6-1 wt% H3PO3, ultrasonically treat for 20-30 min, then dry to constant weight, and then calcine at 360-400 °C for 2-3 h.

[0021] Furthermore, the addition amount of the polyvinylpyrrolidone described in step (1) is 0.2-8% of the total mass of the three metal salts of ferric nitrate, zinc nitrate, and copper nitrate.

[0022] Furthermore, the preparation of the catalyst carrier described in step (2) includes the following steps:

[0023] 1) Mix zirconium nitrate, tetrabutyl titanate, and tetraethyl orthosilicate according to a molar ratio of 1:4-5:16-20, and then add them to anhydrous ethanol and stir to dissolve to obtain solution I;

[0024] 2) Add cetyltrimethylammonium bromide to deionized water and stir to dissolve to obtain solution II;

[0025] 3) Under the stirring condition of 100 - 200 r / min, solution Ⅰ is dropped into solution Ⅱ. After the dropping is completed, the pH is adjusted to 9 - 10 with ammonia water, and then it is transferred to a hydrothermal reactor, heated to 150 - 170 °C, and kept at a constant temperature for reaction for 20 - 26 h;

[0026] 4) After the reaction is completed, centrifugal separation is carried out, and it is washed with absolute ethanol 2 - 3 times and deionized water 3 - 4 times in sequence, then placed in a vacuum drying oven, dried at 60 - 70 °C for 6 - 8 h, and then calcined at 500 - 600 °C for 3 - 4 h to obtain the catalyst support.

[0027] Further, the preparation method of the promoter described in step S1 is as follows: 1-methylimidazole and n-butyl bromide are added to a reaction kettle according to a molar ratio of 1:1 - 1.4, reacted at 80 - 90 °C for 24 - 36 h, then dissolved in deionized water, an equimolar amount of sodium tetrafluoroborate is added, and stirred at room temperature for reaction for 12 - 18 h. After the reaction is completed, the product is extracted with dichloromethane, then washed with deionized water 3 - 5 times, and dichloromethane is removed by vacuum distillation to obtain 1-methyl-3-butylimidazolium tetrafluoroborate; 1-methyl-3-butylimidazolium tetrafluoroborate and potassium carbonate are mixed according to a mass ratio of 2 - 4:1, and ground and mixed evenly in a grinder to obtain the promoter.

[0028] Further, during the dehydrogenation reaction described in step S1, the temperature is controlled at 160 - 250 °C, the space velocity is 0.6 - 1.4 h -1 , and the pressure is 0 - 0.3 MPa.

[0029] Further, the bottom temperature of the de-lighting tower is controlled at 100 - 125 °C, the top temperature is controlled at 95 - 120 °C, and the top pressure is controlled at 0.01 - 0.05 MPa.

[0030] Further, the bottom temperature of the 2-pentanone rectification tower is controlled at 60 - 75 °C, the top temperature is controlled at 50 - 60 °C, and the top pressure is controlled at -0.06 - -0.01 MPa.

[0031] Further, the bottom temperature of the 2-pentanol rectification tower is controlled at 135 - 160 °C, the top temperature is controlled at 115 - 130 °C, and the top pressure is controlled at 0.01 - 0.05 MPa.

[0032] The present invention has the following advantages compared with the prior art:

[0033] 1. The present invention uses 2-pentanol as a raw material, employs a special catalyst and additives, and adopts an upward feed and downward discharge feeding method. The 2-pentanol is fed into a dehydrogenation reactor to carry out a dehydrogenation reaction under the synergistic action of the catalyst and additives. The 2-pentanol reaction liquid is subjected to continuous rectification. Light components are removed in the light component removal tower, and high-purity 2-pentanone is obtained at the top of the heavy component removal tower. The present invention significantly improves the dehydrogenation efficiency of 2-pentanol and greatly reduces the production energy consumption cost.

[0034] 2. The catalyst of the present invention, through the synergistic action of boron and phosphorus, combines a hierarchical pore support and Fe electron regulation to reduce the reaction energy, promote the dehydrogenation reaction, and improve the purity of the product 2-pentanone. The catalyst of the present invention solves the problem of gradually losing activity due to coking and has a long service life. When it and the additive are jointly added to the reaction system, the two act synergistically. The additive can promote the dehydrogenation reaction of 2-pentanol and inhibit the occurrence of side reactions, thereby further improving the yield and purity of the product. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 is a process flow chart for the production of 2-pentanone by dehydrogenation of 2-pentanol according to the present invention;

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

[0037] Figure 3 is a DSC test curve of the catalyst. DETAILED DESCRIPTION OF THE INVENTION

[0038] In order to further explain the present invention, the following specific embodiments are described below.

[0039] Example 1

[0040] A process for the production of 2-pentanone by dehydrogenation of 2-pentanol includes the following steps:

[0041] S1. The raw material is pumped from the 2-pentanol dehydrogenation buffer tank through a deacidifier and a flow meter to a heat exchanger, heated to 240 °C, and then enters the dehydrogenation reactor to carry out a dehydrogenation reaction under the action of a catalyst and an additive. The temperature is controlled at 160 °C, the space velocity is 0.6 h -1 , and the pressure is 0 MPa;

[0042] The addition amount of the catalyst is 1% of the substrate mass, and the addition amount of the additive is 2% of the catalyst mass;

[0043] The preparation of the catalyst includes the following steps:

[0044] (1) Prepare a mixed aqueous solution by mixing iron nitrate, zinc nitrate, and copper nitrate in a mass ratio of 1:2:6. Add polyvinylpyrrolidone to the mixed aqueous solution and disperse it ultrasonically for 20 min to obtain a mixed solution;

[0045] The addition amount of the polyvinylpyrrolidone is 0.2% of the total mass of the three metal salts of iron nitrate, zinc nitrate, and copper nitrate;

[0046] (2) Add a catalyst support to the mixed solution in step (1), load the active components by the equal-volume impregnation method, then dry to a constant weight, and then calcine at 350 °C for 3 h to form a catalyst precursor for standby;

[0047] (3) Immerse the catalyst precursor in a 0.8 wt% H3BO3 ethanol solution, let it stand for 10 h, then dry at 80 °C for 3 h, then immerse it in a 0.6 wt% H3PO3 aqueous solution, ultrasonically treat it for 20 min, then dry to a constant weight, and then calcine at 360 °C for 2 h;

[0048] The preparation of the catalyst support includes the following steps:

[0049] 1) Mix zirconium nitrate, tetrabutyl titanate, and tetraethyl orthosilicate in a molar ratio of 1:4:16, and then add them to anhydrous ethanol and stir to dissolve to obtain solution I;

[0050] 2) Add cetyltrimethylammonium bromide to deionized water and stir to dissolve to obtain solution II;

[0051] 3) Under the stirring condition of 100 r / min, drop solution I into solution II. After the dropping is completed, adjust the pH to 9 with ammonia water, then transfer it to a hydrothermal reactor, heat it to 150 °C, and keep it at a constant temperature for 20 h;

[0052] 4) After the reaction is completed, perform centrifugal separation, wash it twice with anhydrous ethanol and three times with deionized water in sequence, then place it in a vacuum drying oven, dry it at 60 °C for 6 h, and then calcine it at 500 °C for 3 h to obtain the catalyst support;

[0053] The preparation method of the promoter is as follows: Add 1-methylimidazole and n-butyl bromide to the reaction kettle in a molar ratio of 1:1, react at 80 °C for 24 h, then dissolve it in deionized water, add an equimolar amount of sodium tetrafluoroborate, stir and react at room temperature for 12 h. After the reaction is completed, extract the product with dichloromethane, then wash it three times with deionized water, and distill off dichloromethane under reduced pressure to obtain 1-methyl-3-butylimidazolium tetrafluoroborate; Mix 1-methyl-3-butylimidazolium tetrafluoroborate and potassium carbonate in a mass ratio of 2:1, and grind and mix them evenly in a grinder to obtain the promoter;

[0054] S2. After the 2-pentanone mixture obtained from the dehydrogenation reaction is cooled to 40°C in a heat exchanger, the cooled 2-pentanone mixture enters a gas-liquid separator. The liquid-phase material is pumped to a 2-pentanone light-component removal tower to remove light components. The temperature at the bottom of the tower is controlled at 100°C, the temperature at the top of the tower is controlled at 95°C, and the pressure at the top of the tower is controlled at 0.01 MPa.

[0055] S3. The material at the bottom of the 2-pentanone light-component removal tower is pumped to a 2-pentanone rectification tower to remove heavy components. The temperature at the bottom of the tower is controlled at 60°C, the temperature at the top of the tower is controlled at 50°C, the pressure at the top of the tower is controlled at -0.06 MPa, and the material at the top of the tower is the 2-pentanone product.

[0056] S4. The material at the bottom of the 2-pentanone rectification tower is pumped to a 2-pentanol rectification tower to remove heavy components. The temperature at the bottom of the tower is controlled at 135°C, the temperature at the top of the tower is controlled at 115°C, the pressure at the top of the tower is controlled at 0.01 MPa, and the material at the top of the tower is 2-pentanol, which is pumped to a 2-pentanol dehydrogenation buffer tank for recycling.

[0057] Example 2

[0058] A process for producing 2-pentanone by dehydrogenating 2-pentanol includes the following steps:

[0059] S1. The raw material is pumped from the 2-pentanol dehydrogenation buffer tank through a deacidifier and a flowmeter, metered, and then pumped to a heat exchanger. After being heated to 260°C, it enters a dehydrogenation reactor and undergoes a dehydrogenation reaction under the action of a catalyst and an auxiliary agent. The temperature is controlled at 200°C, the space velocity is 1 h -1 , and the pressure is 0.1 MPa.

[0060] The addition amount of the catalyst is 1.5% of the substrate mass, and the addition amount of the auxiliary agent is 2.5% of the catalyst mass.

[0061] The preparation of the catalyst includes the following steps:

[0062] (1) Ferric nitrate, zinc nitrate, and copper nitrate are configured into a mixed aqueous solution according to a mass ratio of 1:2.5:6.5. Polyvinylpyrrolidone is added to the mixed aqueous solution and ultrasonically dispersed for 25 min to obtain a mixed solution.

[0063] The addition amount of the polyvinylpyrrolidone is 4% of the total mass of the three metal salts of ferric nitrate, zinc nitrate, and copper nitrate.

[0064] (2) A catalyst carrier is added to the mixed solution in step (1), and the active components are loaded by the equal-volume impregnation method. Then it is dried to constant weight and calcined at 400°C for 3.5 h to form a catalyst precursor for standby.

[0065] (3) Immerse the catalyst precursor in a 1 wt% ethanol solution of H3BO3. After standing for 11 h, dry it at 85 °C for 3.5 h, then immerse it in an aqueous solution of 0.8 wt% H3PO3. After ultrasonic treatment for 25 min, dry it to constant weight, and then calcine it at 380 °C for 2.5 h;

[0066] The preparation of the catalyst support includes the following steps:

[0067] 1) Mix zirconium nitrate, tetrabutyl titanate, and tetraethyl orthosilicate in a molar ratio of 1:4.5:18, and add them to anhydrous ethanol. Stir and dissolve to obtain Solution I;

[0068] 2) Add cetyltrimethylammonium bromide to deionized water, stir and dissolve to obtain Solution II;

[0069] 3) Under the stirring condition of 150 r / min, drip Solution I into Solution II. After the dripping is completed, adjust the pH to 9.5 with ammonia water, then transfer it to a hydrothermal reactor, heat it up to 160 °C, and keep the temperature constant for 23 h;

[0070] 4) After the reaction is completed, perform centrifugal separation, wash it twice with anhydrous ethanol and three times with deionized water in sequence, then place it in a vacuum drying oven, dry it at 65 °C for 7 h, and then calcine it at 550 °C for 3.5 h to obtain the catalyst support;

[0071] The preparation method of the additive is as follows: Add 1-methylimidazole and n-butyl bromide to the reaction kettle in a molar ratio of 1:1.2. After reacting at 85 °C for 30 h, dissolve it in deionized water, add an equimolar amount of sodium tetrafluoroborate, and stir and react at room temperature for 15 h. After the reaction is completed, extract the product with dichloromethane, then wash it 4 times with deionized water, and remove dichloromethane by vacuum distillation to obtain 1-methyl-3-butylimidazolium tetrafluoroborate; Mix 1-methyl-3-butylimidazolium tetrafluoroborate and potassium carbonate in a mass ratio of 3:1, and grind and mix them evenly in a grinder to obtain the additive;

[0072] S2. After the 2-pentanone mixture obtained after the dehydrogenation reaction is cooled to 40 °C through a heat exchanger, the cooled 2-pentanone mixture enters a gas-liquid separator. The liquid-phase material is pumped to a 2-pentanone light component removal tower to remove light components. Control the tower bottom temperature at 110 °C, the tower top temperature at 105 °C, and the tower top pressure at 0.03 MPa;

[0073] S3. Pump the tower bottom material of the 2-pentanone light component removal tower to a 2-pentanone rectification tower to remove heavy components. Control the tower bottom temperature at 70 °C, the tower top temperature at 55 °C, the tower top pressure at -0.03 MPa, and the tower top material is the 2-pentanone product;

[0074] S4. The material pump at the bottom of the 2-pentanone rectification column pumps the material to the 2-pentanol rectification column to remove heavy components. The bottom temperature is controlled at 145 °C, the top temperature is controlled at 120 °C, the top pressure is controlled at 0.03 MPa, and the top material is 2-pentanol, which is pumped to the 2-pentanol dehydrogenation buffer tank for circulation.

[0075] Example 3

[0076] A process for producing 2-pentanone by dehydrogenating 2-pentanol includes the following steps:

[0077] S1. The raw material is pumped from the 2-pentanol dehydrogenation buffer tank through a deacidifier and a flow meter, and then pumped to a heat exchanger. After being heated to 290 °C, it enters the dehydrogenation reactor and undergoes a dehydrogenation reaction under the action of a catalyst and an auxiliary agent. The temperature is controlled at 250 °C, the space velocity is 1.4 h -1 , and the pressure is 0.3 MPa;

[0078] The addition amount of the catalyst is 2% of the substrate mass, and the addition amount of the auxiliary agent is 3% of the catalyst mass;

[0079] The preparation of the catalyst includes the following steps:

[0080] (1) Ferric nitrate, zinc nitrate and copper nitrate are configured into a mixed aqueous solution according to a mass ratio of 1:3:7. Polyvinylpyrrolidone is added to the mixed aqueous solution and ultrasonically dispersed for 30 min to obtain a mixed solution;

[0081] The addition amount of the polyvinylpyrrolidone is 8% of the total mass of the three metal salts of ferric nitrate, zinc nitrate and copper nitrate;

[0082] (2) A catalyst carrier is added to the mixed solution in step (1), and the active components are loaded by the equal-volume impregnation method, then dried to constant weight, and then calcined at 450 °C for 4 h to form a catalyst precursor for standby;

[0083] (3) The catalyst precursor is immersed in a 1.2 wt% H3BO3 ethanol solution, allowed to stand for 12 h, then dried at 90 °C for 4 h, then immersed in a 1 wt% H3PO3 aqueous solution, ultrasonically treated for 30 min, then dried to constant weight, and then calcined at 400 °C for 3 h;

[0084] The preparation of the catalyst carrier includes the following steps:

[0085] 1) Zirconium nitrate, tetrabutyl titanate and tetraethyl orthosilicate are mixed according to a molar ratio of 1:5:20 and then added to anhydrous ethanol, and stirred and dissolved to obtain solution I;

[0086] 2) Cetyltrimethylammonium bromide is added to deionized water and stirred and dissolved to obtain solution II;

[0087] 3) Under the stirring condition of 200 r / min, solution I was dropped into solution II. After the dropping was completed, the pH was adjusted to 10 with ammonia water, and then it was transferred to a hydrothermal reactor and heated to 170 °C for a constant-temperature reaction for 26 h;

[0088] 4) After the reaction was completed, centrifugal separation was carried out, and it was washed 3 times with absolute ethanol and 4 times with deionized water in sequence, and then placed in a vacuum drying oven and dried at 70 °C for 8 h and then calcined at 600 °C for 4 h to obtain a catalyst support;

[0089] The preparation method of the auxiliary agent is as follows: 1-methylimidazole and n-butyl bromide were added to the reaction kettle according to a molar ratio of 1:1.4, reacted at 90 °C for 36 h, dissolved in deionized water, and an equimolar amount of sodium tetrafluoroborate was added, and stirred and reacted at room temperature for 18 h. After the reaction was completed, the product was extracted with dichloromethane, then washed 5 times with deionized water, and dichloromethane was removed by vacuum distillation to obtain 1-methyl-3-butylimidazolium tetrafluoroborate; 1-methyl-3-butylimidazolium tetrafluoroborate and potassium carbonate were mixed according to a mass ratio of 4:1 and ground and mixed evenly in a grinder to obtain the auxiliary agent;

[0090] S2. After the 2-pentanone mixture obtained after the dehydrogenation reaction was cooled to 40 °C by a heat exchanger, the cooled 2-pentanone mixture entered a gas-liquid separator, and the liquid-phase material was pumped to a 2-pentanone light component removal tower to remove light components. The tower bottom temperature was controlled at 125 °C, the tower top temperature was controlled at 120 °C, and the tower top pressure was controlled at 0.05 MPa;

[0091] S3. The tower bottom material of the 2-pentanone light component removal tower was pumped to a 2-pentanone rectification tower to remove heavy components. The tower bottom temperature was controlled at 75 °C, the tower top temperature was controlled at 60 °C, the tower top pressure was controlled at -0.01 MPa, and the tower top material was 2-pentanone product;

[0092] S4. The tower bottom material of the 2-pentanone rectification tower was pumped to a 2-pentanol rectification tower to remove heavy components. The tower bottom temperature was controlled at 160 °C, the tower top temperature was controlled at 130 °C, the tower top pressure was controlled at 0.05 MPa, and the tower top material was 2-pentanol, which was pumped to a 2-pentanol dehydrogenation buffer tank for circulation.

[0093] 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, increased to 130 °C at 10 °C / min and held for 0 min, increased to 230 °C at 20 °C / min and held for 15 minutes; the carrier gas (N2) 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.

[0094] 1. Optimization research on the 2-pentanol dehydrogenation process

[0095] 1.1 Temperature

[0096] Temperature is one of the key conditions affecting the dehydrogenation of 2 - pentanol. The appropriate temperature is the comprehensive balance result of reaction rate, equilibrium conversion rate, selectivity, catalyst service life, and reaction phase state. The relationship between the saturated vapor pressure of 2 - pentanol and temperature is as shown in Figure 2 shown

[0097] 150 g of dehydrogenation catalyst, mass space velocity 0.8 h -1 the influence on the hydrogen reaction, and the results are shown in Table 1

[0098] Table 1 Influence of temperature on the dehydrogenation reaction of 2 - pentanol

[0099]

[0100]

[0101] As can be seen from Table 1 above, as the temperature rises, the conversion rate of 2 - pentanol gradually increases, from 45.40% to about 82.81%. 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 comprehensively the dehydrogenation reaction effect and the influence of the dehydrogenation catalyst, the temperature is preferably 190 - 240 °C

[0102] 1.2 Mass space velocity

[0103] With 150 g (100 ml) of dehydrogenation catalyst, under the conditions of a reaction temperature of 240 °C and atmospheric pressure, the influence of space velocity on the dehydrogenation reaction of 2 - pentanol was investigated, and the results are shown in Table 2

[0104] Table 2 Conversion rate and selectivity of the dehydrogenation reaction of 2 - pentanol at different space velocities

[0105] Serial number <![CDATA[Air speed (h -1 )]]> Conversion rate of 2-pentanol (%) Selectivity of 2-pentanone (%) 1 0.6 83.07 99.34 2 0.8 82.81 99.52 3 1.0 78.89 99.61 4 1.2 74.68 99.65 5 1.4 67.11 99.68

[0106] As can be seen from Table 2 above, as the space velocity rises, the conversion rate of 2 - pentanol gradually decreases. When the space velocity reaches 1.2 h -1 , the conversion rate of 2 - pentanol is still above 70%. The selectivity shows the opposite trend. As the space velocity increases, the selectivity of 2 - pentanone gradually rises and the by - products gradually decrease

[0107] 1.3 Pressure

[0108] With 150 g of 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 2 - pentanol was investigated, and the results are shown in Table 3

[0109] Table 3 Conversion rate and selectivity of the dehydrogenation reaction of 2 - pentanol at different pressures

[0110] Serial number Pressure (MPa) Conversion rate of 2-pentanol (%) Selectivity of 2-pentanone (%) 1 0 82.81 99.52 2 0.1 78.65 99.57 3 0.2 75.83 99.65 4 0.3 63.29 99.68

[0111] As can be seen from Table 3 above, as the pressure increases, the conversion rate of 2-pentanol decreases significantly. When the pressure reaches 0.2 MPa, the conversion rate of 2-pentanol is 74.83%, and the selectivity is above 99.5%. When the pressure reaches 0.3 MPa, the conversion rate of 2-pentanol decreases significantly to 63.29%.

[0112] In this experiment, a dehydrogenation catalyst was used to conduct a dehydrogenation experiment on 2-pentanol, aiming to prepare 2-pentanone by gas-phase dehydrogenation of 2-pentanol and verify the reaction activity of the catalyst. The experimental device used an adiabatic bed reaction, and the feeding method was from top to bottom. The catalyst was loaded in the dry basis, with a loading mass of 150 g and a loading 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 2-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 2-pentanol is about 70%, and the selectivity of 2-pentanone is above 99.5%.

[0113] 2. Light and heavy component removal unit

[0114] 2.1 In the light component removal unit, the 2-pentanone mixed material obtained from the dehydrogenation reaction is added to the dehydrogenation rectification column for atmospheric pressure batch rectification. The bottom temperature of the column is controlled at 100 - 125 °C, the top temperature of the column is controlled at 95 - 120 °C, and the top pressure of the column is controlled at 0.01 - 0.05 MPa to remove the light components in the 2-pentanone mixed material. The crude 2-pentanone obtained at the bottom of the column is subjected to the next heavy component removal rectification. The specific experimental results are shown in Table 4 below:

[0115] Table 4 Light component removal data

[0116] Batch 2-Pentanol (%) 2-Pentanone (%) Light components (%) Heavy components (%) Raw material 30.87 68.97 / / Top product 0.49 83.32 16.19 / Bottom product 30.99 68.78 / 0.23

[0117] 2.2 Heavy component removal unit

[0118] The crude 2-pentanone material after heavy component removal is added to the 2-pentanol rectification column for atmospheric pressure batch rectification. The bottom temperature of the column is controlled at 60 - 75 °C, the top temperature of the column is controlled at 50 - 60 °C, and the top pressure of the column is controlled at -0.06 - -0.01 MPa. The 2-pentanone product is obtained at the top of the column, and the bottom discharge goes for the next step of 2-pentanol purification. The specific experimental results are shown in Table 5 below.

[0119] Table 5 Heavy component removal data

[0120] Batch 2-Pentanol (%) 2-Pentanone (%) Light components (%) Heavy components (%) Raw material 30.99 68.78 / 0.23 Top product 0.02 99.73 / / Bottom product 97.61 0.04 / 2.35

[0121] 2.3 2-Pentanol recovery and purification

[0122] Add the above bottom material to the 2-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 2-pentanol rectification column. The top material is 2-pentanol, which is returned to dehydrogenate 2-pentanol to prepare 2-pentanone. The specific experimental data are shown in Table 6 below.

[0123] Table 6 Data of removing heavy components

[0124] Batch 2-Pentanol (%) 2-Pentanone (%) Light components (%) Heavy components (%) Raw material 97.61 0.04 / 2.35 Top product 99.53 0.22 0.25 / Bottom product 29.83 1.16 / 69.01

[0125] In summary, the optimal dehydrogenation process conditions are as follows: the reaction 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 2-pentanol is about 70%, and the selectivity of 2-pentanone is above 99.5%.

[0126] 3. Differential scanning calorimetry of the catalyst

[0127] The differential scanning calorimetry (DSC) test information and test curves of the catalyst are shown in Table 7 and Figure 3 as shown.

[0128] Table 7 DSC test information of the catalyst

[0129]

[0130]

[0131] Test method: Put the material into the crucible, seal the crucible and then put it into the test system, and perform the test at a set heating rate until the set temperature is reached.

[0132] The DSC test results of the catalyst are shown in Table 8.

[0133] Table 8 DSC test results of the catalyst

[0134] Temperature range (°C) Peak temperature (°C) Heat release (J / g) Heat absorption (J / g) 262.1～340.9 305.3 64.0 -

[0135] The differential scanning calorimetry test results show that the test material has an obvious exothermic signal at 262.1 °C, and the sample undergoes exothermic decomposition. In the temperature range of 262.1 - 340.9 °C, the heat release of the sample is 64.0 J / g (calculated based on the mass of the catalyst).

[0136] The above are only the preferred specific embodiments 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, making equivalent substitutions or changes, shall be covered by the protection scope of the present invention.

Claims

1. A process for producing 2-pentanone by dehydrogenation of 2-pentanol, characterized in that, It includes the following steps: S1. The raw materials are pumped from the 2-pentanol dehydrogenation buffer tank through a deacidifier and a flowmeter for metering, and then pumped to a heat exchanger. After being heated to 240 - 290 °C, they enter the dehydrogenation reactor and undergo dehydrogenation reaction under the action of a catalyst and an auxiliary agent; S2. The 2-pentanone mixture obtained after the dehydrogenation reaction is cooled to 40 °C through a heat exchanger, and then the cooled 2-pentanone mixture enters a gas-liquid separator. The liquid-phase material is pumped to a 2-pentanone light-component removal tower to remove light components; S3. The bottom material of the 2-pentanone light-component removal tower is pumped to a 2-pentanone rectification tower to remove heavy components, and the top material is the 2-pentanone product; S4. The bottom material of the 2-pentanone rectification tower is pumped to a 2-pentanol rectification tower to remove heavy components, and the top material is 2-pentanol, which is pumped to the 2-pentanol dehydrogenation buffer tank for recycling.

2. The process for producing 2-pentanone by dehydrogenation of 2-pentanol according to claim 1, wherein, In step S1, the addition amount of the catalyst is 1 - 2% of the substrate mass, and the addition amount of the auxiliary agent is 2 - 3% of the catalyst mass.

3. The process for producing 2-pentanone by dehydrogenation of 2-pentanol according to claim 1, characterized in that, The preparation of the catalyst described in step S1 includes the following steps: (1) Ferric nitrate, zinc nitrate, and copper nitrate are configured into a mixed aqueous solution according to a mass ratio of 1:2 - 3:6 - 7. Polyvinylpyrrolidone is added to the mixed aqueous solution and ultrasonically dispersed for 20 - 30 min to obtain a mixed solution; (2) A catalyst carrier is added to the mixed solution in step (1), and the active components are loaded by the equal-volume impregnation method, then dried to constant weight, and then calcined at 350 - 450 °C for 3 - 4 h to form a catalyst precursor for standby; (3) The catalyst precursor is immersed in a 0.8 - 1.2 wt% H3BO3 ethanol solution, left standing for 10 - 12 h, then dried at 80 - 90 °C for 3 - 4 h, then immersed in a 0.6 - 1 wt% H3PO3 aqueous solution, ultrasonically treated for 20 - 30 min, then dried to constant weight, and then calcined at 360 - 400 °C for 2 - 3 h.

4. The process for producing 2-pentanone by dehydrogenation of 2-pentanol according to claim 3, characterized in that, In step (1), the addition amount of the polyvinylpyrrolidone is 0.2 - 8% of the total mass of the three metal salts of ferric nitrate, zinc nitrate, and copper nitrate.

5. The process for producing 2-pentanone by dehydrogenation of 2-pentanol according to claim 3, characterized in that, The preparation of the catalyst carrier described in step (2) includes the following steps: 1) Zirconium nitrate, tetrabutyl titanate, and tetraethyl orthosilicate are mixed according to a molar ratio of 1:4 - 5:16 - 20 and then added to anhydrous ethanol, and stirred and dissolved to obtain solution I; 2) Cetyltrimethylammonium bromide is added to deionized water and stirred and dissolved to obtain solution II; 3) Under the stirring condition of 100 - 200 r / min, solution I is dropped into solution II. After the dropping is completed, the pH is adjusted to 9 - 10 with ammonia water, and then transferred to a hydrothermal reactor, heated to 150 - 170 °C, and kept at a constant temperature for 20 - 26 h; 4) After the reaction is completed, centrifugal separation is carried out, and it is washed with anhydrous ethanol 2 - 3 times and deionized water 3 - 4 times in sequence, then placed in a vacuum drying oven, dried at 60 - 70 °C for 6 - 8 h, and then calcined at 500 - 600 °C for 3 - 4 h to obtain the catalyst carrier.

6. The process for producing 2-pentanone by dehydrogenation of 2-pentanol according to claim 1, wherein The preparation method of the auxiliary agent described in step S1 is as follows: 1-methylimidazole and n-butyl bromide are added to a reaction kettle in a molar ratio of 1:1 to 1.4, reacted at 80-90 °C for 24-36 h, dissolved in deionized water, an equimolar amount of sodium tetrafluoroborate is added, and stirred at room temperature for 12-18 h. After the reaction is completed, the product is extracted with dichloromethane, then washed with deionized water 3-5 times, and dichloromethane is removed by distillation under reduced pressure to obtain 1-methyl-3-butylimidazolium tetrafluoroborate; 1-methyl-3-butylimidazolium tetrafluoroborate and potassium carbonate are mixed in a mass ratio of 2-4:1, and ground and mixed evenly in a grinder to obtain the auxiliary agent.

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

8. The process for producing 2-pentanone by dehydrogenation of 2-pentanol according to claim 1, characterized in that, The bottom temperature of the light component removal tower is controlled at 100-125 °C, the top temperature is controlled at 95-120 °C, and the top pressure is controlled at 0.01-0.05 MPa.

9. The process for producing 2-pentanone by dehydrogenation of 2-pentanol according to claim 1, characterized in that, The bottom temperature of the 2-pentanone rectification tower is controlled at 60-75 °C, the top temperature is controlled at 50-60 °C, and the top pressure is controlled at -0.06 to -0.01 MPa.

10. A process for producing 2-pentanone by dehydrogenation of 2-pentanol according to claim 1, characterized in that, The bottom temperature of the 2-pentanol rectification tower is controlled at 135-160 °C, the top temperature is controlled at 115-130 °C, and the top pressure is controlled at 0.01-0.05 MPa.

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