Process and system for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone

Abstract

The application relates to the technical field of alpha-olefin preparation, and discloses a method for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone, which comprises the following steps: (1) mixing 4-methyl-2-pentanone with hydrogen in the presence of a hydrogenation catalyst to perform a hydrogenation reaction, so as to obtain a 4-methyl-2-pentanol-containing stream; (2) performing ketone removal on the 4-methyl-2-pentanol-containing stream, so as to obtain 4-methyl-2-pentanone and 4-methyl-2-pentanol crude products; and (3) performing dehydration reaction on the 4-methyl-2-pentanol crude products obtained in the step (2) in the presence of a dehydration catalyst, so as to obtain a 4-methyl-1-pentene-containing stream. The method for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone can be simply and effectively used for preparing 4-methyl-1-pentene products, 4-methyl-2-pentanone raw materials are easy to obtain, the reaction conditions are relatively mild, the product distribution is simple, and high-purity 4-methyl-1-pentene products can be prepared.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of α-olefin preparation, in particular, to a method and system for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone. BACKGROUND

[0002] 4-methyl-1-pentene (4MPI), also known as 1-isohexene, is a good α-olefin organic compound, and through its own polymerization, poly-4-methyl-1-pentene (PMP) with high transparency, heat resistance and mechanical properties, electrical properties and superior resistance can be obtained, which is an important polymerization monomer of PMP. In addition, 4MPI can also be used for the copolymerization of linear low density polyethylene resin (LLDPE), which has excellent tensile tear strength and good dielectric properties.

[0003] In recent years, with the expansion of the application and consumption field of material polymerization, the industrial production technology of PMP has developed rapidly. Currently, Philips Company and Japan's Mitsui Company both have their industrialized products, with the trade name of TPX, which are widely used in the fields of electronic appliances, medical devices, microporous materials, packaging, blending modification, etc. In China, with the rapid development of electronic-related industries, PMP has become an excellent mold material for electronic component packaging and a high-frequency connector manufacturing material due to its own shapeability, temperature resistance and very low dielectric constant, and its consumption has increased significantly, with a good market prospect.

[0004] At present, the process technology for producing 4MPI abroad is relatively mature, and the main process is propylene dimerization.

[0005] In 1968, Hambling used a supported metal Na catalyst to realize the industrial production of propylene dimerization reaction, and built the world's first 2000 t / a 4MPI production device, with a single-pass 4MPI selectivity higher than 87%. At the same time, Japan's Mitsui Chemical Company obtained the technical patent authorization from the British ICI Company, and began to produce and enter the market in 1973. Currently, Japan's Mitsui Chemical Company is the only PMP resin manufacturer in the world.

[0006] Compared with foreign countries, the maturity of domestic 4MPI technology is low, and the industry technology patent is mainly held by Japan's Mitsui Chemical Company and the United States Phillips Petroleum Company. Most of the domestic related patent technologies are focused on the application of poly-4MPI downstream products, and currently there is no 4MPI production device in China, and domestic consumption is completely dependent on imports.

[0007] Jiang Heng et al. used solid super-strong alkali K / K2CO3 as catalyst, and found that the reaction temperature was 150℃, the reaction pressure was 8MPa, the space velocity was 1h-1, and the conversion rate of 4-methyl-2-pentanone was 99.9%, and the selectivity of 4-methyl-1-pentene was 99.9%. -1The single-pass conversion rate of propylene dimerization to 4-methyl-1-pentene is 20%, and the selectivity of 4-methyl-1-pentene is 88%.

[0008] CN111574317A discloses a synthesis process of 4-methyl-1-pentene, mainly including dimerization of propylene under the condition of a basic salt loaded with an alkali metal as a catalyst, and then preparing 4-methyl-1-pentene through a separation process. The purity of the 4-methyl-1-pentene can reach 99.5%, and the by-product is 1-hexene and other alpha-olefins, which meets the requirements of industrial polymerization reaction of 4-methyl-1-pentene.

[0009] In summary, the current 4MP1 synthesis process mainly adopts propylene dimerization method, but the propylene dimerization method mainly has the disadvantages of high reaction pressure, many oligomerization and isomerization by-products, etc. And currently there is no other process route for producing 4MP1.

[0010] The process method for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone disclosed in the application involves relatively mild reaction conditions, the raw material is easy to obtain, and the product distribution is relatively simple, so that high-purity 4MP1 product can be easily separated and prepared. SUMMARY

[0011] The purpose of the application is to solve the technical problems of high reaction pressure, many oligomerization and isomerization by-products, etc. in the propylene dimerization method in the prior art. The application provides a method and system for preparing 4-methyl-1-pentene.

[0012] In order to achieve the above-mentioned purpose, the application provides a method for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone, which comprises the following steps:

[0013] (1) hydrogenation reaction of 4-methyl-2-pentanone and hydrogen gas in the presence of a hydrogenation catalyst to obtain a stream containing 4-methyl-2-pentanol;

[0014] (2) deketonization of the stream containing 4-methyl-2-pentanol to obtain 4-methyl-2-pentanone and 4-methyl-2-pentanol crude product;

[0015] (3) dehydration reaction of the 4-methyl-2-pentanol crude product obtained in step (2) in the presence of a dehydration catalyst to obtain a stream containing 4-methyl-1-pentene.

[0016] The second aspect of the application provides a system for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone, which comprises a hydrogenation reactor, a deketonization tower and a dehydration reactor, wherein,

[0017] The hydrogenation reactor is configured to hydrogenate 4-methyl-2-pentanone with hydrogen to obtain a stream containing 4-methyl-2-pentanol.

[0018] The deketonization column is connected to the hydrogenation reactor and configured to deketonize the stream containing 4-methyl-2-pentanol from the hydrogenation reactor to obtain 4-methyl-2-pentanone and 4-methyl-2-pentanol crude product.

[0019] The dehydration reactor is connected to the deketonization column and configured to dehydrate the 4-methyl-2-pentanol crude product from the deketonization column to obtain a stream containing 4-methyl-1-pentene.

[0020] Compared with the existing propylene dimerization production method, the method for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone can be used to simply and effectively prepare 4-methyl-1-pentene product, the raw material 4-methyl-2-pentanone is easy to obtain, the reaction condition is relatively mild, the product distribution is simple, and high-purity 4-methyl-1-pentene product can be prepared. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 FIG. 1 is a schematic diagram of a method and system for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone according to an embodiment of the present application.

[0022] REFERENCE NUMERALS

[0023] 1-hydrogenation reactor; 2-gas-liquid separator; 3-deketonization column; 4-dehydration reactor; 5-de-light column; 6-refining column; 7-dehydration column. DETAILED DESCRIPTION

[0024] The endpoints of the ranges and any values disclosed herein are not limited to the precise values stated. The endpoints of the ranges and the values are approximate values and should be understood to include values approximately nearest to them. For ranges of values, the endpoints of the ranges are combinable with one another to form new ranges of values that are not expressly disclosed.

[0025] The present application provides a method for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone (MIBK), which comprises the following steps:

[0026] (1) hydrogenating 4-methyl-2-pentanone with hydrogen in the presence of a hydrogenation catalyst to obtain a stream containing 4-methyl-2-pentanol (MIBC);

[0027] (2) subjecting the 4-methyl-2-pentanol-containing stream to deketonization to obtain 4-methyl-2-pentanone and crude 4-methyl-2-pentanol;

[0028] (3) subjecting the crude 4-methyl-2-pentanol obtained in step (2) to dehydration reaction in the presence of a dehydration catalyst to obtain a stream containing 4-methyl-1-pentene.

[0029] In the present application, in step (1), the 4-methyl-2-pentanone and hydrogen gas can be mixed and preheated before being introduced into the hydrogenation reactor; the preheating conditions are not particularly limited as long as the 4-methyl-2-pentanone is completely gasified, for example, the preheating temperature can be 120-150°C.

[0030] According to some embodiments of the present application, in step (1), the hydrogenation reaction conditions can include: the liquid phase volume space velocity of 4-methyl-2-pentanone is 0.05-3 h -1 , the molar ratio of hydrogen gas to 4-methyl-2-pentanone is (2-30):1, the hydrogenation reaction temperature is 80-160°C, and the hydrogenation reaction pressure is normal pressure to 3.5 MPa.

[0031] According to preferred embodiments of the present application, the hydrogenation reaction conditions include: the liquid phase volume space velocity of 4-methyl-2-pentanone is 0.2-2.0 h -1 , the molar ratio of hydrogen gas to 4-methyl-2-pentanone is (5-15):1, the hydrogenation reaction temperature is 100-140°C, and the hydrogenation reaction pressure is 0.5-2.5 MPa.

[0032] In the present application, the suitable hydrogenation catalyst is selected from a catalyst in which at least two metal active components are supported on a catalyst or dispersed by a catalyst carrier. The metal active component can be selected from one or more than two combinations of IB, IIB, IIIB, IVB, VB, VIB, VIIB, VIIIB group transition metals, lanthanide series metals, and IIIA, IVA, VA, VIA group metals in the periodic table, such as nickel, cobalt, copper, manganese, ruthenium, tin, iron, tungsten, rhenium, and / or rhodium, etc.

[0033] According to some embodiments of the present application, the hydrogenation catalyst is a heterogeneous catalyst.

[0034] According to some embodiments of the present application, the hydrogenation catalyst includes a carrier and Ni and La supported on the carrier.

[0035] Preferably, the content of the Ni is 10-15 wt% based on the total weight of the hydrogenation catalyst, and the weight ratio of the Ni to La is (10-20):1.

[0036] Preferably, the specific surface area of the hydrogenation catalyst is 145-175 m 2 / g, a pore volume of 0.50-0.8 mL / g, and a most probable pore diameter of 6.0-10.0 nm.

[0037] In the present application, the carrier suitable for use as the hydrogenation catalyst can be selected from the group consisting of silicon dioxide, aluminum oxide, titanium dioxide, zirconium oxide, magnesium oxide, activated carbon, graphite, or any combination thereof, such as silicon dioxide-aluminum oxide, titanium dioxide-aluminum oxide, and the like. Preferably, the hydrogenation catalyst carrier is silicon dioxide, aluminum oxide, activated carbon, zirconium oxide, or any combination thereof. More preferably, the catalyst carrier is silicon dioxide, γ-aluminum oxide, or a combination thereof.

[0038] Preferably, the first carrier is selected from at least one of aluminum oxide, silicon dioxide, and titanium dioxide;

[0039] According to some embodiments of the present application, a gas-liquid separation step is further included between the step (1) and the step (2), and the stream containing 4-methyl-2-pentanol is subjected to gas-liquid separation to obtain a gas phase component containing hydrogen and a liquid phase component containing 4-methyl-2-pentanol. The liquid phase component containing 4-methyl-2-pentanol obtained by the gas-liquid separation is subjected to deketonization. The gas phase component containing hydrogen can be sent to the step (1) as a raw material for the hydrogenation reaction.

[0040] The deketonization is carried out in a deketonization column having a theoretical plate number of 40-65, and the feed inlet of the deketonization column is located in the middle upper part of the column. The conditions for the deketonization are not particularly limited as long as the 4-methyl-2-pentanone crude in the stream containing 4-methyl-2-pentanol in the step (1) can be separated from the system (for example, the unreacted 4-methyl-2-pentanone can be separated from the top of the column and returned to the hydrogenation reactor in the step (1) as a starting raw material for the hydrogenation reaction). For example, the operating temperature at the top of the column is 90-125°C, preferably 100-115°C, and the operating pressure at the top of the column is 0.01-0.2 MPa, preferably 0.01-0.1 MPa.

[0041] In the present application, the 4-methyl-2-pentanol crude can further contain part of the unremoved 4-methyl-2-pentanone.

[0042] According to some embodiments of the present application, in the step (3), the conditions for the dehydration reaction can include: the liquid phase volume space velocity of 4-methyl-2-pentanol is 0.05-1.5 h -1 , the dehydration reaction temperature is 250-450°C, and the dehydration reaction pressure is normal pressure to 0.5 MPa.

[0043] Preferably, the dehydration reaction conditions include: the liquid phase volume space velocity of 4-methyl-2-pentanol is 0.2-1.0h -1 , the dehydration reaction temperature is 290-360℃, and the dehydration reaction pressure is normal pressure to 0.1MPa.

[0044] According to some embodiments of the present application, the dehydration catalyst comprises calcium oxide and zirconium oxide, and the content of calcium oxide in terms of metal elements is 0.1-5wt% (0.1wt%, 0.5wt%, 1.5wt%, 2wt%, 2.5wt%, 3wt%, 3.5wt%, 4wt%, 4.5wt%, 5wt% or any value between the above values) based on the total weight of the dehydration catalyst.

[0045] Preferably, the specific surface area of the dehydration catalyst is 45-90m 2 / g, the pore volume is 0.25-0.50mL / g, and the most probable pore diameter is 3.5-6.0nm.

[0046] In the present application, the dehydration catalyst can also comprise other metal active components such as nickel, barium, zinc, etc., and the zirconium oxide can also be a properly modified zirconium oxide carrier, for example, a proper amount of other metal oxides such as titanium dioxide, tin oxide, neodymium oxide, thorium oxide, etc. are added in the shaping or co-precipitation for regulation. In the present application, the suitable dehydration catalyst is a calcium oxide-zirconium oxide catalyst.

[0047] In the present application, the catalyst and catalyst carrier suitable for 4-methyl-2-pentanone hydrogenation reaction and 4-methyl-2-pentanol dehydration reaction can be modified and regulated in any way. For example, the pore structure of the carrier oxide can be adjusted by using a pore-expanding agent or hydrothermal treatment to improve the selectivity and stability of the overall catalyst; for another example, the suitable acidity and alkalinity can be regulated by adding certain element compounds in the catalyst preparation process to improve the catalyst activity and selectivity; for another example, the stability of the catalyst can be improved by adding certain metals such as cerium in the carrier to play a synergistic effect with the active components nickel and copper, which can effectively improve the catalyst life; for another example, the surface properties of the catalyst can be adjusted to reduce the deposition of certain compounds or heavy components on the catalyst surface or to improve the dispersion of the active components on the surface to prolong the catalyst life.

[0048] The catalysts (such as catalysts for hydrogenation reaction and dehydration reaction) according to the present application can be prepared by conventional methods, such as impregnation method, ion exchange method, blending method, kneading method, co-precipitation, deposition-precipitation, ammonium vapor deposition, melt-extraction, ball milling and sol-gel method. More preferred methods include one or more of impregnation, co-precipitation and sol-gel method. The above-mentioned methods for preparing catalysts are mostly mature technologies known to those skilled in the art. For example, a certain amount of carrier is weighed, and the precursor of the metal active component is loaded on the carrier by one or more steps of impregnation, followed by drying, calcination, reduction, and finally obtaining the catalyst product; or the precursor of the active component can be sprayed on the carrier by spraying method, followed by drying, calcination, reduction, and finally obtaining the catalyst product; or the catalyst raw powder can be prepared by co-precipitation method, followed by drying, decomposition, and then granulation, tabletting, reduction and other steps to obtain the desired catalyst product.

[0049] The shape and size of the catalyst according to the present application can be arbitrarily customized, such as spherical, strip-shaped, columnar, ring-shaped, etc., and the size is about 0.3-10 mm, more preferably 0.5-5 mm. The present application does not have special restrictions on the above-mentioned size, and is mainly designed according to the fixed bed reactor described in the present application to facilitate installation, reduce bed pressure and other requirements.

[0050] The catalyst according to the present application is preferably reduced before use. The reduction method of the catalyst is generally using a mixture of hydrogen and nitrogen (the content of hydrogen can be 20-30 vol%). When pure hydrogen is used for reduction, the temperature rising rate needs to be strictly controlled. From the perspective of temperature control of catalyst reduction, a mixture with lower hydrogen content is preferred. During reduction, the larger the gas space velocity is, the better, because the larger space velocity can quickly remove the heat generated by the reaction, maintain the temperature of the catalyst bed stable, and avoid damage to the catalyst caused by flying temperature. For example, the space velocity of the mixture is 2000-4000 m 3 / m 3 ·h -1The temperature of the catalyst reduction can be determined according to the composition of the specific catalyst. For the catalysts described in the present application, the temperature of the catalyst bed can be gradually increased at a rate of 10-20°C / h, and the temperature is kept at about 230°C for 5-10 hours, then the temperature of the catalyst bed is gradually increased at a rate of 5-20°C / h until 350-400°C, and the temperature is kept at this temperature for 10-15 hours. Then it is slowly decreased to room temperature, for example, the rate of temperature decrease is 10-20°C / h. After the temperature is decreased to room temperature, nitrogen is switched in, and dry air is gradually mixed into the nitrogen, and the amount of air is gradually increased to increase the oxygen content in the mixed gas. The amount of air is adjusted according to the change of the temperature of the catalyst to avoid the temperature of the catalyst bed being too high, for example, not more than 50°C. When the catalyst is reduced in situ in the corresponding reactor, the temperature of the catalyst after reduction is decreased to the reaction temperature, and then the catalyst is used.

[0051] According to a preferred embodiment, the hydrogenation catalyst is prepared according to the following steps:

[0052] Loading of active components (Ni, La): The γ-Al2O3 carrier is weighed, the weight of the corresponding nickel salt and lanthanum salt is calculated according to the content of the nickel loading component, and a corresponding aqueous solution is prepared, the above aqueous solution is added to the γ-Al2O3 carrier for equal volume impregnation, and after standing for 1-3h, it is dried at 100-150°C for 1-3h, and then calcined and decomposed at 340-380°C in a muffle furnace for 1-6h to obtain an oxidation state hydrogenation catalyst; wherein the type of the nickel salt and the lanthanum salt is not particularly limited as long as it can meet the needs of the present application, the nickel salt can be nickel nitrate hexahydrate; and the lanthanum salt can be lanthanum nitrate;

[0053] Reduction: the above obtained oxidation state hydrogenation catalyst is reduced with a mixed gas containing hydrogen and nitrogen (the volume ratio of hydrogen to nitrogen is 1:(2-4)), the reduction temperature increasing rate is 100-150°C / h, the temperature is increased to 220-280°C and kept for 1-6h, then the temperature is increased to 400-450°C and kept for 1-10h, then the temperature is decreased to room temperature to obtain the hydrogenation catalyst.

[0054] According to a preferred embodiment, the dehydration catalyst is prepared according to the following steps:

[0055] A certain amount of zirconium oxynitrate powder is weighed and dissolved in deionized water to obtain a zirconium oxynitrate aqueous solution (solution ①), the weight of the corresponding calcium salt is calculated according to the calcium content, and the calcium salt is prepared into a calcium salt aqueous solution (solution ②), the solution ① and the solution ② are subjected to parallel flow neutralization, and the pH value (8.5-9.0) and the temperature (75-80℃) of the neutralization process are controlled, after the neutralization is completed, aging is carried out at 80-100℃ for 1-3h, and after filtration and washing, drying (100-150℃, 1-10h), calcination (300-400℃, 1-6h) are carried out in sequence to obtain a dehydrated catalyst precursor; wherein, the type of the calcium salt is not particularly limited, as long as it can meet the needs of the present application, for example, the calcium salt can be calcium nitrate tetrahydrate;

[0056] The above-obtained dehydrated catalyst precursor is reduced by hydrogen, the reduction temperature rising rate is 120-160℃ / h, the temperature is raised to 200-250℃ and stays for 1-5h, then the temperature is raised to 400-450℃ and stays for 1-10h, then the temperature is reduced to room temperature, and a dehydrated catalyst is obtained.

[0057] In the present application, the catalyst carrier and the preparation method thereof can be changed according to the above detailed description. For example, any known hydrogenation catalyst, catalyst carrier or modified catalyst carrier can be used.

[0058] In the present application, the 4-methyl-1-pentene-containing stream obtained in step (3) is a mixture containing 4-methyl-1-pentene, 4-methyl-2-pentene, 4-methyl-2-pentanol and 4-methyl-2-pentanone.

[0059] According to some embodiments of the present application, the method can further comprise the following steps:

[0060] (4) separating the 4-methyl-1-pentene-rich stream and the 4-methyl-2-pentanol and 4-methyl-2-pentanone-rich stream from the 4-methyl-1-pentene-containing stream obtained in step (3);

[0061] (5) purifying the 4-methyl-1-pentene-rich stream separated in step (4) to obtain a 4-methyl-1-pentene product;

[0062] (6) returning the 4-methyl-2-pentanol and 4-methyl-2-pentanone-rich stream separated in step (4) to step (2) after water removal (dehydration).

[0063] According to some embodiments of the present application, the separation in step (3) is preferably carried out in a light-removing column.

[0064] According to some embodiments of the present application, the number of theoretical plates of the light-removing column is 30-65, preferably 35-60.

[0065] According to some embodiments of the present application, the feed inlet of the light-removing column is located in the middle-lower part of the light-removing column, the operating temperature at the top of the column is 45-70℃, preferably 50-65℃, and the operating pressure at the top of the column is 0.01-2MPa, preferably 0.01-0.1MPa.

[0066] According to some embodiments of the present application, the refining is performed in a refining column (4MP1 refining column).

[0067] According to some embodiments of the present application, the number of theoretical plates of the refining column is 45-80, preferably 50-75, the feed inlet of the refining column is located in the middle-upper part of the refining column, the operating temperature at the top of the column is 40-60℃, preferably 45-55℃, and the operating pressure at the top of the column is 0.01-0.2MPa, preferably 0.01-0.15MPa.

[0068] In the present application, the obtained 4-methyl-2-pentene and other components at the bottom of the refining column can be taken as by-products without special treatment.

[0069] In the present application, the purpose of water removal is to remove water in the stream, and according to some embodiments of the present application, the water removal is performed in a dehydration column.

[0070] Preferably, the number of theoretical plates of the dehydration column is 40-60, the feed inlet of the dehydration column is located in the middle-lower part of the dehydration column, the operating temperature at the top of the column is 95-103℃, and the operating pressure at the top of the column is 0.01-0.20MPa.

[0071] According to some embodiments of the present application, after the dehydration of the 4-methyl-2-pentanone crude and the 4-methyl-2-pentanol crude separated in step (4), a stream containing 4-methyl-2-pentanone is obtained and returned to the deketonization column in step (2).

[0072] As shown in Figure 1 The second aspect of the present application provides a system for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone, characterized in that the system comprises: a hydrogenation reactor 1, a deketonization column 3, and a dehydration reactor 4, wherein,

[0073] The hydrogenation reactor 1 is used for mixing 4-methyl-2-pentanone with hydrogen to perform a hydrogenation reaction, thereby obtaining a stream containing 4-methyl-2-pentanol;

[0074] The deketonization column 3 is connected to the hydrogenation reactor 1 and is used for deketonizing the stream containing 4-methyl-2-pentanol from the hydrogenation reactor 1, thereby obtaining 4-methyl-2-pentanone and 4-methyl-2-pentanol crude;

[0075] The deketone reactor 4 is connected to the deketone column 3, and is used for dehydrating the 4-methyl-2-pentanol crude from the deketone column 3 to obtain a stream containing 4-methyl-1-pentene.

[0076] According to some embodiments of the present application, the system further comprises a gas-liquid separator 2, a light-removing column 5, a refining column 6 and a dehydration column 7,

[0077] The gas-liquid separator 2 is connected to the hydrogenation reactor 1 and the deketone column 3, and is used for separating the stream containing 4-methyl-2-pentanol from the hydrogenation reactor 1 into a gas phase component containing hydrogen and a liquid phase component containing 4-methyl-2-pentanol, and sending the liquid phase component containing 4-methyl-2-pentanol to the deketone column 3;

[0078] The light-removing column 5 is connected to the dehydration reactor 4, and is used for separating the stream containing 4-methyl-1-pentene from the dehydration reactor 4 into a stream rich in 4-methyl-1-pentene and a stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone;

[0079] The refining column 6 is connected to the light-removing column 5, and is used for refining the stream rich in 4-methyl-1-pentene from the light-removing column 5 to obtain 4-methyl-1-pentene product;

[0080] The dehydration column 7 is connected to the light-removing column 5, and is used for dehydrating the stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone from the light-removing column 5 and returning it to the deketone column for deketonization.

[0081] In the present application, normal pressure refers to "0.1 MPa" unless otherwise specified.

[0082] According to a preferred embodiment of the present application, in combination with Figure 1 The method for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone according to the present application specifically comprises the following process when used in the system for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone according to the present application:

[0083] (a) hydrogenation reaction: the 4-methyl-2-pentanone and hydrogen are mixed and preheated, and then introduced into the hydrogenation reactor 1 in the presence of a hydrogenation catalyst to perform hydrogenation reaction, thereby obtaining a stream containing 4-methyl-2-pentanol; then, the stream containing 4-methyl-2-pentanol obtained above is sent to the gas-liquid separator 2 to perform gas-liquid separation, thereby obtaining a gas phase component containing hydrogen and a liquid phase component containing 4-methyl-2-pentanol; and the gas phase component containing hydrogen is returned to the hydrogenation reactor 1 as the hydrogen source for hydrogenation reaction;

[0084] (b) Deketation: The liquid phase component containing 4-methyl-2-pentanol is sent to the deketation tower 3 for deketation, and the unreacted 4-methyl-2-pentanone overhead product (4-methyl-2-pentanone) and the bottom product containing 4-methyl-2-pentanol (crude 4-methyl-2-pentanol) are separated. The unreacted 4-methyl-2-pentanone overhead product is returned to the hydrogenation reactor 1 in step (a) as the starting material for the hydrogenation reaction.

[0085] (c) Dehydration reaction: In the presence of the above dehydration catalyst, the above product containing 4-methyl-2-pentanol is fed into dehydration reactor 4 for dehydration reaction to obtain a stream containing 4-methyl-1-pentene.

[0086] (d) Separation (removal of light components): The stream containing 4-methyl-1-pentene is fed to the removal column 5 to separate the stream rich in 4-methyl-1-pentene and the stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone.

[0087] (f) 4MP1 purification: The product from the top of the light removal tower 5 containing 4-methyl-1-pentene is sent to the 4MP1 purification tower 6 for purification, and the 4-methyl-1-pentene product from the top of the tower and the 4-methyl-2-pentene and other components from the bottom of the tower are separated.

[0088] (g) Dehydration: The bottom product (crude 4-methyl-2-pentanol and crude 4-methyl-2-pentanone) containing 4-methyl-2-pentanol is fed into dehydration tower 7 to separate the top product containing water and the bottom product containing 4-methyl-2-pentanol and 4-methyl-2-pentanone; then the bottom product of 4-methyl-2-pentanol and 4-methyl-2-pentanone is returned to the deketination tower 3 of step (b) for deketination.

[0089] The present invention will be described in detail below through embodiments.

[0090] The following embodiments will all be combined with Figure 1 The method for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone according to the present invention is described herein. Unless otherwise stated, the specific operation of the process is as described above.

[0091] The specific formulas for conversion rate and selectivity involved in the examples are as follows:

[0092]

[0093]

[0094]

[0095] The following preparation examples illustrate the preparation of hydrogenation catalysts and dehydration catalysts.

[0096] Preparation Example A1

[0097] Active component (Ni and La) loading: The weighed γ-Al2O3 support, the weight of the corresponding nickel nitrate hexahydrate and lanthanum nitrate was calculated according to the content of nickel and lanthanum loading components and weighed, and an aqueous solution was prepared. The above solution was added to the γ-Al2O3 support for equal volume impregnation, and after standing for 2 h, it was dried at 120 ℃ for 2 h, and then calcined and decomposed in a muffle furnace at 360 ℃ for 4 h to obtain an oxidation state catalyst.

[0098] Reduction: The oxidation state hydrogenation catalyst obtained in the previous step was reduced with a mixed gas of 25 vol% hydrogen and 75 vol% nitrogen, the reduction temperature was raised at a rate of 120 ℃ / h, the temperature was raised to 250 ℃ and held for 3 hours, then the temperature was raised to 420 ℃ and held for 8 hours, then the temperature was lowered to room temperature to obtain a hydrogenation catalyst. The content of Ni was 14.6 wt%, the content of La was 0.97 wt%, and the balance was γ-Al2O3. The specific surface area of the hydrogenation catalyst was 173 m 2 / g, the pore volume was 0.53 mL / g, and the most probable pore diameter was 9.2 nm.

[0099] Preparation Example A2

[0100] Preparation was carried out in the same manner as in Preparation Example A1, except that the amount of nickel nitrate hexahydrate and lanthanum nitrate was changed, so that the specific content composition of the obtained hydrogenation catalyst was as follows: the content of Ni was 12.9 wt%, the content of La was 0.86 wt%, and the balance was γ-Al2O3. The specific surface area of the hydrogenation catalyst was 165 m 2 / g, the pore volume was 0.55 mL / g, and the most probable pore diameter was 8.4 nm.

[0101] Preparation Example A3

[0102] Preparation was carried out in the same manner as in Preparation Example A1, except that the amount of nickel nitrate hexahydrate and lanthanum nitrate was changed, so that the specific content composition of the obtained hydrogenation catalyst was as follows: the content of Ni was 11.2 wt%, the content of La was 1.12 wt%, and the balance was γ-Al2O3. The specific surface area of the hydrogenation catalyst was 159 m 2 / g, the pore volume was 0.58 mL / g, and the most probable pore diameter was 9.6 nm.

[0103] Preparation Example B1

[0104] A certain amount of zirconyl nitrate powder was dissolved in deionized water to obtain a zirconyl nitrate aqueous solution (solution 1). The amount of calcium nitrate tetrahydrate was calculated according to the calcium content, and the calcium nitrate tetrahydrate was dissolved in deionized water to obtain a calcium nitrate tetrahydrate aqueous solution (solution 2). The solution 1 and the solution 2 were mixed and neutralized, and the pH value (8.5-9.0) and the temperature (75-80°C) of the neutralization process were controlled. After the neutralization was completed, the mixture was aged at 90°C for 2h, filtered and washed, and then dried (120°C, 5h) and calcined (350°C, 5h) in sequence to obtain a dehydrated catalyst precursor.

[0105] The catalyst precursor obtained in the previous step was reduced by hydrogen. The temperature was raised to 220°C at a rate of 150°C / h, and then the temperature was maintained at 220°C for 4h. Then the temperature was raised to 450°C and maintained at 450°C for 6h. Then the temperature was lowered to room temperature, thereby obtaining a dehydrated catalyst. The specific composition of the dehydrated catalyst was as follows: the content of Ca was 2.85wt%, and the balance was zirconia.

[0106] Preparation Example B2

[0107] Preparation was carried out in the same manner as in Preparation Example B1, except that the amount of calcium nitrate tetrahydrate was changed. The specific content composition of the obtained dehydrated catalyst was as follows: the content of Ca was 4.64wt%, and the balance was zirconia.

[0108] Preparation Example B3

[0109] Preparation was carried out in the same manner as in Preparation Example B1, except that the amount of calcium nitrate tetrahydrate was changed. The specific content composition of the obtained dehydrated catalyst was as follows: the content of Ca was 0.35wt%, and the balance was zirconia.

[0110] Preparation Example B4

[0111] Preparation was carried out in the same manner as in Preparation Example B1, except that the amount of calcium nitrate tetrahydrate was changed. The specific content composition of the obtained dehydrated catalyst was as follows: the content of Ca was 6.12wt%, and the balance was zirconia.

[0112] Example 1

[0113] (1) Hydrogenation reaction: 4-methyl-2-pentanone and hydrogen were mixed and preheated, and then introduced into a hydrogenation reactor in the presence of the hydrogenation catalyst obtained in Preparation Example A1 to carry out hydrogenation reaction, thereby obtaining a stream containing 4-methyl-2-pentanol. The specific conditions of the hydrogenation reaction included: the liquid phase volume space velocity of 4-methyl-2-pentanone was 1.25h -1, the molar ratio of hydrogen to 4-methyl-2-pentanone is 13:1, the temperature of the hydrogenation reaction is 120°C, and the pressure of the hydrogenation reaction is 1.9 MPa; then, the obtained stream containing 4-methyl-2-pentanol is sent to a gas-liquid separator to perform gas-liquid separation, to obtain a gas phase component containing hydrogen and a liquid phase component containing 4-methyl-2-pentanol; and the gas phase component containing hydrogen is returned to the hydrogenation reactor as the hydrogen source for the hydrogenation reaction; wherein the conversion rate of methyl isobutyl ketone is 99.8%, and the selectivity of methyl isobutyl carbinol is 100%.

[0114] (2) De-ketonization: the liquid phase component containing 4-methyl-2-pentanol is sent to a de-ketonization column to perform de-ketonization, to separate and obtain column top product (4-methyl-2-pentanone) of incompletely reacted 4-methyl-2-pentanone and column bottom product (4-methyl-2-pentanol crude product) containing 4-methyl-2-pentanol, and the column top product of incompletely reacted 4-methyl-2-pentanone is returned to the hydrogenation reactor of step (1) to be used as the starting material for the hydrogenation reaction, wherein the theoretical plate number of the de-ketonization column is 45, the feed inlet is located at the 19th plate, the operating temperature at the column top is 112.1°C, and the operating pressure at the column top is 0.05 MPa;

[0115] (3) Dehydration reaction: the column bottom product containing 4-methyl-2-pentanol obtained in the above Preparation Example B1 is sent to a dehydration reactor in the presence of the dehydration catalyst obtained in the above Preparation Example B1 to perform dehydration reaction, to obtain a stream containing 4-methyl-1-pentene; wherein the specific process conditions of the dehydration reaction are as follows: the liquid phase volume space velocity of 4-methyl-2-pentanol is 0.35 h -1 -1, the temperature of the dehydration reaction is 296°C, and the pressure of the dehydration reaction is normal pressure; wherein the conversion rate of 4-methyl-2-pentanol is 84.0%, and the selectivity of 4-methyl-1-pentene is 83.33%;

[0116] (4) De-light: the stream containing 4-methyl-1-pentene is sent to a de-light column to separate and obtain column top product (stream rich in 4-methyl-1-pentene) containing 4-methyl-1-pentene and column bottom product (stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone) containing 4-methyl-2-pentanol; wherein the theoretical plate number of the de-light column is 48, the feed inlet is located at the 22nd plate, the operating temperature at the column top is 61.2°C, and the operating pressure at the column top is 0.06 MPa;

[0117] (5) 4MP1 refining: the de-light column top product containing 4-methyl-1-pentene is sent to a 4MP1 refining column to perform refining, to separate and obtain 4-methyl-1-pentene product at the column top and components such as 4-methyl-2-pentene at the column bottom; wherein the theoretical plate number of the 4MP1 refining column is 55, the feed inlet is located at the 29th plate, the operating temperature at the column top is 51°C, and the operating pressure at the column top is 0.04 MPa.

[0118] (6) Water removal: The above column still product containing 4-methyl-2-pentanol (a stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone) is sent to a dehydration column for water removal to separate a column overhead product containing water and a column still product containing 4-methyl-2-pentanol and 4-methyl-2-pentanone, wherein the theoretical plate number of the dehydration column is 56, the feed inlet is located at the 32nd plate, the column overhead temperature is 101.2°C, and the column overhead pressure is 0.07 MPa; the above column still product containing 4-methyl-2-pentanol and 4-methyl-2-pentanone is then returned and sent to the deketonization column of step (2) for deketonization. The material analysis results of each operating unit are shown in Table 1 below:

[0119] Table 1

[0120]

[0121] Example 2

[0122] (1) Hydrogenation reaction: The 4-methyl-2-pentanone and hydrogen gas are mixed and preheated, and then introduced into a hydrogenation reactor in the presence of the hydrogenation catalyst obtained in the above Preparation Example A2 to perform hydrogenation reaction to obtain a stream containing 4-methyl-2-pentanol; the specific conditions of the hydrogenation reaction include: the liquid phase volume space velocity of 4-methyl-2-pentanone is 1.8 h -1 -1, the molar ratio of hydrogen gas to 4-methyl-2-pentanone is 6:1, the temperature of the hydrogenation reaction is 110°C, and the pressure of the hydrogenation reaction is 2.5 MPa; then, the above obtained stream containing 4-methyl-2-pentanol is sent to a gas-liquid separator to perform gas-liquid separation to obtain a gas phase component containing hydrogen gas and a liquid phase component containing 4-methyl-2-pentanol; and the gas phase component containing hydrogen gas is returned to the above hydrogenation reactor as the hydrogen source for the hydrogenation reaction; wherein the conversion rate of methyl isobutyl ketone is 99.9%, and the selectivity of methyl isobutyl carbinol is 100%.

[0123] (2) Deketonization: The above liquid phase component containing 4-methyl-2-pentanol is sent to a deketonization column for deketonization to separate a column overhead product of incompletely reacted 4-methyl-2-pentanone (4-methyl-2-pentanone) and a column still product containing 4-methyl-2-pentanol, and the column overhead product of incompletely reacted 4-methyl-2-pentanone is returned and sent to the hydrogenation reactor of step (1) as the starting material for the hydrogenation reaction, wherein the theoretical plate number of the deketonization column is 55, the feed inlet is located at the 23rd plate, the operating temperature of the column overhead is 107.6°C, and the operating pressure of the column overhead is 0.08 MPa;

[0124] (3) Dehydration reaction: In the presence of the dehydration catalyst obtained in Preparation Example B2 above, the product from the bottom of the column containing 4-methyl-2-pentanol was fed into a dehydration reactor for dehydration reaction to obtain a stream containing 4-methyl-1-pentene; wherein, the specific process conditions for the dehydration reaction were: the liquid hourly space velocity of 4-methyl-2-pentanol was 0.72 h⁻¹. -1 The dehydration reaction was carried out at a temperature of 323℃ and a pressure of 0.07 MPa; the conversion rate of 4-methyl-2-pentanol was 79.5%, and the selectivity of 4-methyl-1-pentene was 84.28%.

[0125] (4) Light weight removal: The stream containing 4-methyl-1-pentene is sent to the light weight removal tower to separate the top product containing 4-methyl-1-pentene (the stream rich in 4-methyl-1-pentene) and the bottom product containing 4-methyl-2-pentanol (the stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone); wherein, the theoretical number of plates of the light weight removal tower is 53, the feed inlet is located on the 25th plate, the operating temperature at the top of the tower is 52℃, and the operating pressure at the top of the tower is 0.03MPa;

[0126] (5) 4MP1 purification: The above-mentioned product from the light removal tower containing 4-methyl-1-pentene is sent to the 4MP1 purification tower for purification, and the 4-methyl-1-pentene product at the top of the tower and the 4-methyl-2-pentene and other components at the bottom of the tower are separated; wherein, the theoretical number of plates of the 4MP1 purification tower is 68, the feed inlet is located on the 36th plate, the operating temperature at the top of the tower is 52.3℃, and the operating pressure at the top of the tower is 0.09MPa;

[0127] (6) Dehydration: The bottom product containing 4-methyl-2-pentanol (a stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone) is fed into a dehydration tower for dehydration, separating a water-containing top product and a bottom product containing 4-methyl-2-pentanol and 4-methyl-2-pentanone. The dehydration tower has a theoretical number of 63 plates, with the feed inlet located on the 38th plate. The top temperature is 97.4℃, and the top pressure is 0.05MPa. The bottom product containing 4-methyl-2-pentanol and 4-methyl-2-pentanone is then returned to the deketination tower in step (2) for deketination. The material analysis results for each operating unit are shown in Table 2 below.

[0128] Table 2

[0129]

[0130] Example 3

[0131] (1) Hydrogenation reaction: the hydrogenation catalyst obtained in the above Preparation Example A3 was charged into a hydrogenation reactor, and a mixture of 4-methyl-2-pentanone and hydrogen was preheated and then introduced into the hydrogenation reactor to carry out hydrogenation reaction, thereby obtaining a stream containing 4-methyl-2-pentanol; the specific conditions of the hydrogenation reaction included: the liquid space velocity of 4-methyl-2-pentanone was 0.5 h -1 -1, the temperature of the hydrogenation reaction was 135°C, and the pressure of the hydrogenation reaction was 1.3 MPa; then, the above obtained stream containing 4-methyl-2-pentanol was sent into a gas-liquid separator to carry out gas-liquid separation, thereby obtaining a gas phase component containing hydrogen and a liquid phase component containing 4-methyl-2-pentanol; and the gas phase component containing hydrogen was returned to the above hydrogenation reactor as the hydrogen source for the hydrogenation reaction; wherein the conversion rate of methyl isobutyl ketone was 99.91%, and the selectivity of methyl isobutyl carbinol was 100%.

[0132] (2) Ketone removal: the above liquid phase component containing 4-methyl-2-pentanol was sent to a ketone removal column to carry out ketone removal, thereby separating and obtaining a column top product of unreacted 4-methyl-2-pentanone (4-methyl-2-pentanone) and a column bottom product containing 4-methyl-2-pentanol, and returning the column top product of unreacted 4-methyl-2-pentanone to the hydrogenation reactor of step (1) as the starting material for the hydrogenation reaction; wherein the theoretical plate number of the ketone removal column was 62, the feed inlet was located at the 27th plate, the operating temperature at the top of the column was 103.5°C, and the operating pressure at the top of the column was 0.06 MPa;

[0133] (3) Dehydration reaction: the above column bottom product containing 4-methyl-2-pentanol was sent to a dehydration reactor in the presence of the dehydration catalyst obtained in the above Preparation Example B3 to carry out dehydration reaction, thereby obtaining a stream containing 4-methyl-1-pentene; wherein the specific process conditions of the dehydration reaction included: the liquid space velocity of 4-methyl-2-pentanol was 0.95 h -1 -1, the temperature of the dehydration reaction was 345°C, and the pressure of the dehydration reaction was 0.04 MPa; wherein the conversion rate of 4-methyl-2-pentanol was 86.9%, and the selectivity of 4-methyl-1-pentene was 81.7%;

[0134] (4) Light removal: the stream containing 4-methyl-1-pentene was sent to a light removal column to separate and obtain a column top product containing 4-methyl-1-pentene (a stream rich in 4-methyl-1-pentene) and a column bottom product containing 4-methyl-2-pentanol (a stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone); wherein the theoretical plate number of the light removal column was 39, the feed inlet was located at the 20th plate, the operating temperature at the top of the column was 55.6°C, and the operating pressure at the top of the column was 0.08 MPa;

[0135] (5) 4MP1 refining: the 4-methyl-l-pentene-containing overhead product of the light-removing column is sent to a 4MP1 refining column for refining, to separate 4-methyl-l-pentene product at the column top and 4-methyl-2-pentene and other components at the column bottom; the 4MP1 refining column has 72 theoretical plates, the feed inlet is at the 40th plate, the operating temperature at the column top is 49.2°C, and the operating pressure at the column top is 0.06 MPa;

[0136] (6) Water removal: the 4-methyl-2-pentanol-containing column bottom product (a stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone) is sent to a dehydration column for water removal, to separate water-containing overhead product and 4-methyl-2-pentanol and 4-methyl-2-pentanone-containing column bottom product, wherein the dehydration column has 52 theoretical plates, the feed inlet is at the 29th plate, the column top temperature is 104.3°C, and the column top pressure is 0.05 MPa; the 4-methyl-2-pentanol and 4-methyl-2-pentanone-containing column bottom product is then returned to the deketonization column of step (2) for deketonization. The material analysis results of each operating unit are shown in Table 3 below:

[0137] Table 3

[0138]

[0139]

[0140] Example 4

[0141] (1) Hydrogenation reaction: the 4-methyl-2-pentanone and hydrogen gas are mixed and preheated, and then introduced into a hydrogenation reactor in the presence of the hydrogenation catalyst obtained in the above Preparation Example Al, to perform hydrogenation reaction, to obtain a stream containing 4-methyl-2-pentanol; the specific conditions of the hydrogenation reaction include: the liquid phase volume space velocity of 4-methyl-2-pentanone is 1.25 h -1 -1, the molar ratio of hydrogen gas to 4-methyl-2-pentanone is 13:1, the temperature of the hydrogenation reaction is 120°C, and the pressure of the hydrogenation reaction is 1.9 MPa; then, the obtained stream containing 4-methyl-2-pentanol is sent to a gas-liquid separator for gas-liquid separation, to obtain a gas phase component containing hydrogen gas and a liquid phase component containing 4-methyl-2-pentanol; and the gas phase component containing hydrogen gas is returned to the hydrogenation reactor as the hydrogen source for the hydrogenation reaction; wherein the conversion rate of methyl isobutyl ketone is 99.8%, and the selectivity of methyl isobutyl carbinol is 100%.

[0142] (2) De-ketone: the liquid phase component containing 4-methyl-2-pentanol is sent to a de-ketone column to carry out de-ketone, to separate the overhead product of unreacted 4-methyl-2-pentanone (4-methyl-2-pentanone) and the bottom product containing 4-methyl-2-pentanol (4-methyl-2-pentanol crude product), and the overhead product of unreacted 4-methyl-2-pentanone is returned to the hydrogenation reactor of step (1) as the starting material for hydrogenation reaction, wherein the theoretical plate number of the de-ketone column is 45, the feed inlet is located at the 19th plate, the operating temperature at the top of the column is 112.1°C, and the operating pressure at the top of the column is 0.05 MPa;

[0143] (3) Dehydration reaction: the bottom product containing 4-methyl-2-pentanol is sent to a dehydration reactor to carry out dehydration reaction in the presence of zirconium oxide as the dehydration catalyst, to obtain a stream containing 4-methyl-1-pentene; wherein the specific process conditions of the dehydration reaction are: the liquid phase volume space velocity of 4-methyl-2-pentanol is 0.35 h -1 , the temperature of the dehydration reaction is 296°C, and the pressure of the dehydration reaction is normal pressure; wherein the conversion rate of 4-methyl-2-pentanol is 82.02%, and the selectivity of 4-methyl-1-pentene is 58.54%;

[0144] (4) De-light: the stream containing 4-methyl-1-pentene is sent to a de-light column to separate the overhead product containing 4-methyl-1-pentene (a stream rich in 4-methyl-1-pentene) and the bottom product containing 4-methyl-2-pentanol (a stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone); wherein the theoretical plate number of the de-light column is 49, the feed inlet is located at the 25th plate, the operating temperature at the top of the column is 60.8°C, and the operating pressure at the top of the column is 0.04 MPa;

[0145] (5) 4MP1 refining: the overhead product of the de-light column containing 4-methyl-1-pentene is sent to a 4MP1 refining column to carry out refining, to separate the 4-methyl-1-pentene product at the top and the components such as 4-methyl-2-pentene at the bottom; wherein the theoretical plate number of the 4MP1 refining column is 61, the feed inlet is located at the 34th plate, the operating temperature at the top of the column is 51.9°C, and the operating pressure at the top of the column is 0.04 MPa;

[0146] (6) Water removal: The above column still product containing 4-methyl-2-pentanol (a stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone) is sent to a dehydration column for water removal to separate a column top product containing water and a column still product containing 4-methyl-2-pentanol and 4-methyl-2-pentanone, wherein the theoretical plate number of the dehydration column is 54, the feed inlet is located at the 30th plate, the column top temperature is 100.9°C, and the column top pressure is 0.05 MPa; and then the above column still product containing 4-methyl-2-pentanol and 4-methyl-2-pentanone is sent back to the deketonization column of step (2) for deketonization. The material analysis results of each operating unit are shown in Table 4 below.

[0147] Table 4

[0148]

[0149] Example 5

[0150] (1) Hydrogenation reaction: The 4-methyl-2-pentanone and hydrogen gas are mixed and preheated, and then introduced into a hydrogenation reactor in the presence of the hydrogenation catalyst obtained in the above Preparation Example Al to perform hydrogenation reaction to obtain a stream containing 4-methyl-2-pentanol; the specific conditions of the hydrogenation reaction include: the liquid phase volume space velocity of 4-methyl-2-pentanone is 1.25 h -1 -1, the molar ratio of hydrogen gas to 4-methyl-2-pentanone is 13:1, the temperature of the hydrogenation reaction is 120°C, and the pressure of the hydrogenation reaction is 1.9 MPa; then, the above obtained stream containing 4-methyl-2-pentanol is sent to a gas-liquid separator to perform gas-liquid separation to obtain a gas phase component containing hydrogen gas and a liquid phase component containing 4-methyl-2-pentanol; and the gas phase component containing hydrogen gas is returned to the above hydrogenation reactor as the hydrogen source for the hydrogenation reaction; wherein the conversion rate of methyl isobutyl ketone is 99.8%, and the selectivity of methyl isobutyl carbinol is 100%.

[0151] (2) Deketonization: The above liquid phase component containing 4-methyl-2-pentanol is sent to a deketonization column for deketonization to separate a column top product of unreacted 4-methyl-2-pentanone (4-methyl-2-pentanone) and a column still product containing 4-methyl-2-pentanol (4-methyl-2-pentanol crude product), and the column top product of unreacted 4-methyl-2-pentanone is returned to the hydrogenation reactor of step (1) as the starting material for the hydrogenation reaction, wherein the theoretical plate number of the deketonization column is 45, the feed inlet is located at the 19th plate, the operating temperature of the column top is 112.1°C, and the operating pressure of the column top is 0.05 MPa;

[0152] (3) Dehydration: The column bottom product containing 4-methyl-2-pentanol obtained in the above step (2) was fed into a dehydration reactor in the presence of the dehydration catalyst obtained in the above Preparation Example B4 to perform a dehydration reaction, thereby obtaining a stream containing 4-methyl-l-pentene; wherein the specific process conditions of the dehydration reaction were as follows: the liquid space velocity of 4-methyl-2-pentanol was 0.35 h -1 -1, the temperature of the dehydration reaction was 296°C, and the pressure of the dehydration reaction was normal pressure; wherein the conversion rate of 4-methyl-2-pentanol was 79.03%, and the selectivity of 4-methyl-l-pentene was 48.1%;

[0153] (4) Light-ends removal: The stream containing 4-methyl-l-pentene was fed into a light-ends removal column to separate a column top product (a stream rich in 4-methyl-l-pentene) and a column bottom product (a stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone); wherein the theoretical plate number of the light-ends removal column was 49, the feed inlet was located at the 26th plate, the operating temperature at the column top was 62.3°C, and the operating pressure at the column top was 0.06 MPa;

[0154] (5) 4MP1 purification: The column top product of the light-ends removal column containing 4-methyl-l-pentene was fed into a 4MP1 purification column to perform purification, thereby separating a 4-methyl-l-pentene product at the column top and components such as 4-methyl-2-pentene at the column bottom; wherein the theoretical plate number of the 4MP1 purification column was 58, the feed inlet was located at the 30th plate, the operating temperature at the column top was 51.2°C, and the operating pressure at the column top was 0.05 MPa;

[0155] (6) Water removal: The column bottom product (a stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone) was fed into a dehydration column to perform water removal, thereby separating a column top product containing water and a column bottom product containing 4-methyl-2-pentanol and 4-methyl-2-pentanone; wherein the theoretical plate number of the dehydration column was 52, the feed inlet was located at the 28th plate, the temperature at the column top was 101.0°C, and the pressure at the column top was 0.04 MPa; and then the column bottom product containing 4-methyl-2-pentanol and 4-methyl-2-pentanone was fed back into the deketonization column of step (2) to perform deketonization. The material analysis results of each operation unit were as shown in Table 5:

[0156] Table 5

[0157]

[0158] The preferred embodiments of the present application are described in detail above, but the present application is not limited thereto. Within the technical concept of the present application, various simple modifications can be made to the technical solutions of the present application, including that each technical feature is combined in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the present application and fall within the protection scope of the present application.

Claims

1. A process for the preparation of 4-methyl- 1-pentene from 4-methyl-2-pentanone, characterized in that, The method comprises the following steps: (1) hydrogenating 4-methyl-2-pentanone in the presence of a hydrogenation catalyst to obtain a stream containing 4-methyl-2-pentanol; the hydrogenation catalyst comprises a carrier and Ni and La supported on the carrier; the content of the Ni is 10-15 wt% based on the total weight of the hydrogenation catalyst, and the weight ratio of the Ni to the La is (10-20):1; the carrier of the hydrogenation catalyst is selected from at least one of alumina, silica and titania; The conditions of the hydrogenation reaction include: the liquid phase volume space velocity of 4-methyl-2-pentanone is 0.2-2.0h -1 -1, the molar ratio of hydrogen to 4-methyl-2-pentanone is (5-15):1, the temperature of the hydrogenation reaction is 100-120℃, and the pressure of the hydrogenation reaction is 0.5-2.5MPa. (2) deketonizing the stream containing 4-methyl-2-pentanol to obtain 4-methyl-2-pentanone and 4-methyl-2-pentanol crude product; the deketonization is performed in a deketonization tower, the deketonization tower has a theoretical plate number of 40-65, the feed inlet of the deketonization tower is located in the middle upper part of the deketonization tower, the operating temperature at the top of the deketonization tower is 90-125 ℃, and the operating pressure at the top of the deketonization tower is 0.01-0.2 MPa; (3) dehydrating the 4-methyl-2-pentanol crude product obtained in step (2) in the presence of a dehydration catalyst to obtain a stream containing 4-methyl-1-pentene; the dehydration catalyst comprises calcium oxide and zirconium oxide, and the content of the calcium oxide, in terms of metal elements, is 0.1-5 wt% based on the total weight of the dehydration catalyst.

2. The method of claim 1, wherein, The method further comprises a step of gas-liquid separation between step (1) and step (2), the stream containing 4-methyl-2-pentanol is subjected to gas-liquid separation to obtain a gas phase component containing hydrogen and a liquid phase component containing 4-methyl-2-pentanol, and the liquid phase component containing 4-methyl-2-pentanol obtained by the gas-liquid separation is subjected to deketonization.

3. The method of claim 1 or 2, wherein, In step (2), the deketonization is performed in a deketonization tower, the operating temperature at the top of the deketonization tower is 100-115 ℃, and the operating pressure at the top of the deketonization tower is 0.01-0.1 MPa.

4. The method of claim 1 or 2, wherein, In step (3), the dehydration reaction conditions include: the liquid phase volume space velocity of 4-methyl-2-pentanol is 0.05-1.5h -1 -1, the dehydration reaction temperature is 250-450℃, and the dehydration reaction pressure is normal pressure to 0.5MPa.

5. The method of claim 1 or 2, wherein, In step (3), the conditions of the dehydration reaction include: the liquid phase volume space velocity of 4-methyl-2-pentanol is 0.2-1.0 h -1 , the dehydration reaction temperature is 290-360℃, and the dehydration reaction pressure is normal pressure.

6. The method of claim 1 or 2, wherein, The method further comprises the following steps: (4) separating the stream containing 4-methyl-1-pentene obtained in step (3) to obtain a stream rich in 4-methyl-1-pentene and a stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone; (5) refining the stream rich in 4-methyl-1-pentene obtained in step (4) to obtain 4-methyl-1-pentene product; (6) returning the stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone obtained in step (4) to step (2) after water removal.

7. The method of claim 6, wherein, The separation in step (4) is performed in a light-removing tower, the light-removing tower has a theoretical plate number of 30-65, the feed inlet of the light-removing tower is located in the middle lower part of the light-removing tower, the operating temperature at the top of the light-removing tower is 45-70 ℃, and the operating pressure at the top of the light-removing tower is 0.01-2 MPa.

8. The method of claim 7, wherein, the light-removing tower has a theoretical plate number of 35-60, the operating temperature at the top of the light-removing tower is 50-65 ℃, and the operating pressure at the top of the light-removing tower is 0.01-0.1 MPa.

9. The method of claim 8, wherein, The refining is performed in a refining tower, the refining tower has a theoretical plate number of 45-80, the feed inlet of the refining tower is located in the middle upper part of the refining tower, the operating temperature at the top of the refining tower is 40-60 ℃, and the operating pressure at the top of the refining tower is 0.01-0.2 MPa.

10. The method of claim 9, wherein, The number of theoretical plates of the refining tower is 50-75, the operating temperature at the top of the tower is 45-55 ℃, and the operating pressure at the top of the tower is 0.01-0.15 MPa.

11. The method of claim 6, wherein, The water removal is performed in a dewatering tower, The number of theoretical plates of the dewatering tower is 40-60, the feed inlet of the dewatering tower is located at the lower part of the dewatering tower, the operating temperature at the top of the tower is 95-103 ℃, and the operating pressure at the top of the tower is 0.01-0.20 MPa.

12. The method of claim 1, wherein, The method further comprises a system for preparing 4-methyl-1-pentene from 4-methyl-2-pentanone, the system comprising: a hydrogenation reactor (1), a deketonization tower (3), and a dewatering reactor (4), wherein, The hydrogenation reactor (1) is used for mixing 4-methyl-2-pentanone with hydrogen to perform a hydrogenation reaction, to obtain a stream containing 4-methyl-2-pentanol; The deketonization tower (3) is connected to the hydrogenation reactor (1) and is used for performing deketonization on the stream containing 4-methyl-2-pentanol from the hydrogenation reactor (1), to obtain 4-methyl-2-pentanone and 4-methyl-2-pentanol crude product; The dewatering reactor (4) is connected to the deketonization tower (3) and is used for performing dewatering reaction on the 4-methyl-2-pentanol crude product from the deketonization tower (3), to obtain a stream containing 4-methyl-1-pentene.

13. The method of claim 12, wherein, The system further comprises: a gas-liquid separator (2), a light-removing tower (5), a refining tower (6), and a dewatering tower (7), The gas-liquid separator (2) is connected to the hydrogenation reactor (1) and the deketonization tower (3) and is used for performing gas-liquid separation on the stream containing 4-methyl-2-pentanol from the hydrogenation reactor (1), to obtain a gas phase component containing hydrogen and a liquid phase component containing 4-methyl-2-pentanol, and to send the liquid phase component containing 4-methyl-2-pentanol into the deketonization tower (3); The light-removing tower (5) is connected to the dewatering reactor (4) and is used for separating the stream containing 4-methyl-1-pentene from the dewatering reactor (4), to obtain a stream rich in 4-methyl-1-pentene and a stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone; The refining tower (6) is connected to the light-removing tower (5) and is used for refining the stream rich in 4-methyl-1-pentene from the light-removing tower (5), to obtain 4-methyl-1-pentene product; The dewatering tower (7) is connected to the light-removing tower (5) and is used for removing water from the stream rich in 4-methyl-2-pentanol and 4-methyl-2-pentanone from the light-removing tower (5) and returning the stream to the deketonization tower for deketonization.

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