Method for increasing carbon number of straight-chain alpha-unsaturated olefin

Abstract

The invention provides a method for synthesizing a straight-chain alpha-unsaturated olefin product with increased carbon number by using straight-chain alpha-unsaturated olefin as a raw material, and the method comprises the following steps: carrying out hydroformylation reaction on CN alpha-olefin, carbon monoxide and hydrogen in the presence of a first catalyst to generate CN + 1 aldehyde; reducing the CN + 1 aldehyde obtained in the step 1 to obtain CN + 1 alcohol; and dehydrating at least a part of the CN + 1 alcohol obtained in the step 2 to obtain the CN + 1 alpha-olefin. According to the method disclosed by the invention, hydroformylation reaction can be carried out under relatively low gas pressure, and extremely high raw material conversion rate and target product selectivity are realized.

Description

Technical Field

[0001] The present application mainly relates to the field of catalysis, and more specifically to a method for synthesizing a linear α-unsaturated olefin product with an increased carbon number using a linear α-unsaturated olefin as a raw material. Background Art

[0002] Linear α-olefins (LAOs), also known as "straight-chain α-olefins," are olefins with carbon-carbon double bonds at their ends and a straight (unbranched) structure. They are a very important class of organic raw materials and chemical intermediates, widely used in the synthesis of polyethylene copolymers, surfactants, advanced synthetic lubricants (polyα-olefins), plasticizers, and fine chemicals. Compared to α-olefins with lower carbon numbers (such as ethylene, 1-propylene, and 1-butene), α-olefins with higher carbon numbers (such as 1-hexene, 1-heptene, 1-octene, 1-nonene, and 1-decene, especially those with odd carbon numbers) undoubtedly have greater economic value. For example, these higher carbon number α-olefins can be used as comonomers in the production of linear low-density polyethylene (LLDPE), high-density polyethylene (HDPE), and polyolefin elastomers (POE), achieving excellent impact resistance, tear resistance, and tensile strength. These properties are difficult to match with lower carbon number polyα-olefin copolymers such as poly(1-butene), and they have broader development prospects. Therefore, in recent years, the industry has increasingly demanded these higher carbon number linear α-olefins.

[0003] Paradoxically, there are always serious problems in the prior art for synthesizing linear α-olefins with higher carbon numbers.

[0004] For example, one synthetic route involves obtaining α-olefins through olefin metathesis, such as by ethenolysis of internal olefins. However, this process is severely constrained by reaction equilibrium and selectivity, and it can produce olefins with shorter carbon chains than the starting internal olefins, which is extremely disadvantageous for the synthesis of higher-carbon-number α-olefins mentioned above.

[0005] Another approach is to synthesize olefin products with higher carbon numbers by dimerizing, trimerizing, or polymerizing lower olefins (such as ethylene or butadiene). However, the problem with this method is that it is extremely difficult to control the type and structure of the generated products. The synthesized products contain a large amount of by-products, such as branched olefins, non-α-olefins, and olefins with unwanted carbon numbers. The separation and treatment of these impurities seriously reduce the practicality of this technology.

[0006] Another approach involves using linear α-olefins with a relatively low carbon number as feedstock and increasing their carbon number through hydroformylation, reduction, and dehydration steps to obtain linear α-olefin target products with higher carbon numbers. However, this technology currently suffers from numerous serious drawbacks, one of which is the high requirements for reaction conditions. For example, while the hydroformylation of 1-pentene using a cobalt-based catalyst can slightly improve selectivity for 1-hexanol, the reaction requires very high reaction pressures (total pressure of carbon monoxide and hydrogen >7 MPa), which significantly increases the capital construction and maintenance costs of the reaction equipment. Using low-pressure techniques, such as rhodium-based catalysts, while the reaction pressure can be slightly reduced, the n-to-isomer ratio of the product aldehyde is very low, resulting in a selectivity of only 75% for the target n-aldehyde product. 25% of the branched aldehyde products cannot be hydrogenated to alcohols, which are then further dehydrated to form linear α-olefins with a carbon number of +1, resulting in reduced reaction efficiency.

[0007] Therefore, the art is very eager to develop a technology that can achieve a high normal-to-isomer ratio of aldehyde synthesis at a lower pressure, so as to meet the needs of further hydrogenation and dehydration to obtain α-olefins with a carbon number of +1. This new technology can overcome the problems existing in the existing technology. Summary of the Invention

[0008] In response to the above problems, the inventors conducted extensive and in-depth research and developed a novel method to effectively solve the above problems that have been unresolved in the art so far, thereby completing the present invention.

[0009] The present invention provides a C N α-olefin preparation C N+1 A process for producing alpha-olefins, the process comprising the steps of:

[0010] Step 1: In the presence of a first catalyst, the C N α-olefins react with carbon monoxide and hydrogen to form C N+1 aldehyde;

[0011] Step 2: C obtained in step 1 N+1 Aldehyde is reduced to obtain C N+1 alcohol;

[0012] Step 3: C obtained in step 2 N+1 At least a portion of the alcohol is dehydrated to obtain the C N+1 α-olefins;

[0013] Among them C N Indicates that the molecule contains N carbon atoms, C N+1 Indicates that the molecule contains N+1 carbon atoms, where N is an integer from 3 to 16;

[0014] The first catalyst contains a metal element, a first organic ligand and a CO ligand, and the first catalyst optionally further contains a second organic ligand;

[0015] The metal element is selected from one or more of the following: rhodium, cobalt, iridium, ruthenium, iron, nickel, palladium, platinum, and osmium;

[0016] The first organic ligand has a structure shown in Formula I:

[0017]

[0018] In Formula I, R1-R 10 Each of them is independently selected from the group consisting of hydrogen, C1-C6 alkyl, C1-C6 alkoxy, C6-C16 aryl, amino, and halogen; R 11 -R 14 Each of the groups is independently selected from the group consisting of C1-C6 alkyl, C1-C6 alkoxy; A, B, C and D are each independently 0-5;

[0019] The second organic ligand has a structure shown in Formula II:

[0020]

[0021] In Formula II, each of R15, R16 and R17 is independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy; and P, Q and R are independently 1-5.

[0022] According to one embodiment of the present application, in the first catalyst, the molar ratio of the metal element to the first organic ligand is 1:0.5 to 1:5.

[0023] According to another embodiment of the present application, in the first catalyst, the molar ratio of the metal element to the second organic ligand is 1:0 to 1:1.

[0024] According to another embodiment of the present application, in the first catalyst, the molar ratio of the metal element to the CO ligand is 1:1 to 1:3.

[0025] According to another embodiment of the present application, in the first catalyst, the molar ratio of the first organic ligand to the second organic ligand is 10:0 to 10:1.

[0026] According to another embodiment of the present application, the C N α-olefins, C N+1 Aldehyde, C N+1 Alcohol and C N+1 α-olefins all have a straight chain structure and do not include a branched structure in the molecule. N+1 The aldehyde group of aldehyde and C N+1The hydroxyl groups of alcohols are located at the ends of their molecular chains.

[0027] According to another embodiment of the present application, the C N The α-olefin is 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene or 1-nonene.

[0028] According to another embodiment of the present application, in step 1, the molar ratio of hydrogen to carbon monoxide is 2:1 to 1:2.

[0029] According to another embodiment of the present application, in step 1, the total pressure of hydrogen and carbon monoxide is 0.5-5.0 MPaG.

[0030] According to another embodiment of the present application, in the step 1, the reaction temperature is 65-120°C.

[0031] According to another embodiment of the present application, in step 1, the reaction time is 20 minutes to 6 hours.

[0032] According to another embodiment of the present application, in the step 2, the C obtained in the step 1 is reacted with the catalyst in the presence of a second catalyst. N+1 Aldehyde reacts with hydrogen to obtain C N+1 alcohol; the second catalyst comprises a carrier, a main catalytic element supported on the carrier, and a promoter element supported on the carrier.

[0033] According to another embodiment of the present application, in the step 2, the carrier is selected from at least one of the following: alumina, silicon oxide, silicon-aluminum composite oxide, molecular sieve, zeolite, and diatomaceous earth.

[0034] According to another embodiment of the present application, in step 2, the main catalytic element is selected from at least one of the following: Cu, Cr, Ni, Mg, and Na.

[0035] According to another embodiment of the present application, in the step 2, the auxiliary element is selected from one or more of the following: Zn, Zr, Co, Ca, Sr, and Ba.

[0036] According to another embodiment of the present application, in the step 2, the weight ratio of the sum of the weight of the main catalytic element and the auxiliary element to the carrier is (main catalytic element + auxiliary element): carrier = 0.01:100 to 1.5:100.

[0037] According to another embodiment of the present application, in the step 2, the molar ratio of the main catalytic element to the auxiliary element is 1:0.2 to 1:5.

[0038] According to another embodiment of the present application, in step 2, the temperature of the reduction reaction is 180-250°C. According to another embodiment of the present application, in step 2, the hydrogen pressure is 1-5 MPa. According to another embodiment of the present application, in step 2, C N+1 Aldehyde for 0.1-1.5 hours -1 Feed at a space velocity of .

[0039] According to another embodiment of the present application, in the step three, the C obtained in step two is catalyzed in the presence of a third catalyst. N+1 The alcohol is dehydrated to obtain the C N+1 α-olefin; the third catalyst is alumina or a supported catalyst, wherein the supported catalyst comprises a carrier and a metal element supported on the carrier.

[0040] According to one embodiment of the present application, in the step three, the third catalyst is alumina, such as α-alumina, preferably activated α-alumina.

[0041] According to another embodiment of the present application, in step three, the third catalyst is a supported catalyst, and the support is selected from at least one of the following: alumina, silicon-aluminum composite oxide, molecular sieve, and zeolite.

[0042] According to another embodiment of the present application, in step three, the metal element is selected from at least one of the following: barium, vanadium, aluminum, and tungsten.

[0043] According to another embodiment of the present application, in the step three, the weight ratio of the metal element to the carrier is 0.03:100 to 1:100.

[0044] According to another embodiment of the present application, in step 3, the reaction temperature is 260-330°C. According to another embodiment of the present application, in step 3, the reaction pressure is 0.12-0.6 MPa. According to another embodiment of the present application, in step 3, C N+1 Alcohol for 0.05-1 hour -1 Feed at a space velocity of .

[0045] Some embodiments of the present application are introduced below with reference to the accompanying drawings, but the protection scope of the present application is not limited to these embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 A process flow chart according to one embodiment of the method of the present invention is shown, wherein 1-octene is used as an exemplary raw material, and the target product 1-nonene is obtained through hydroformylation, hydrogenation and dehydration processes;

[0047] Figure 2 shows a gas chromatogram of a liquid product obtained after a hydroformylation reaction according to one embodiment of the present application;

[0048] Figure 3 The catalyst complex in the reaction solution according to Example 1 is shown 31 P NMR spectrum, in which signal peaks related to the catalyst structure were shown at -17.2 ppm, 26.5 ppm and 24.5 ppm, respectively;

[0049] Figure 4 The results show that the reaction solution obtained in Example 1 was heated at 90°C for one week under N2 atmosphere. 31 P NMR spectrum;

[0050] Figure 5 The results show that the reaction solution obtained in Example 2 was heated at 90°C for one week under N2 atmosphere. 31 P NMR spectrum. DETAILED DESCRIPTION

[0051] To help those skilled in the art understand the features and effects of this application, the following provides a general description and definition of the terms and expressions used in the specification and claims. Unless otherwise indicated, all technical and scientific terms used herein have the ordinary meanings understood by those skilled in the art in connection with this application. In the event of any conflict, the definitions in this specification shall prevail.

[0052] "Range" disclosed herein is in the form of a lower limit and an upper limit. It can be one or more lower limits, and one or more upper limits, respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower limit and upper limit define the boundaries of a particular range. All ranges that can be defined in this way are inclusive and combinable, i.e., any lower limit can be combined with any upper limit to form a range. For example, a range of 60-120 and 80-110 is listed for a particular parameter, and it is understood that a range of 60-110 and 80-120 is also expected. In addition, if the minimum range values listed are 1 and 2, and if the maximum range values listed are 3, 4, and 5, then the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5.

[0053] In the present invention, unless otherwise specified, all embodiments and preferred embodiments mentioned herein can be combined with each other to form a new technical solution.

[0054] In the present invention, unless otherwise specified, all technical features and preferred features mentioned herein can be combined with each other to form a new technical solution.

[0055] In the present invention, unless otherwise specified, the term "comprising" as used herein may be open-ended or closed-ended. For example, the term "comprising" may mean that other components not listed may also be included, or only the listed components may be included.

[0056] The method of the present invention utilizes N ) of linear alpha olefins as raw materials, through hydroformylation, reduction and dehydration to provide carbon number increase (C N+1 ) of linear alpha olefins. The method steps of the present invention can be repeated to further increase the carbon number. For example, if the steps of the present invention are repeated twice, a carbon number of (C N+2 ) of linear α-olefins; repeat three times to obtain a carbon number of (C N+3 ) of linear α-olefins; repeat four times, then a carbon number of (C N+4 ) of a linear alpha olefin; and so on, until a linear alpha olefin having the desired carbon number is obtained.

[0057] In the present invention, C N The N in represents the total number of carbon atoms in the linear α-olefin as the initial reaction raw material. According to one embodiment of the present invention, N is an integer of 3-16, preferably N is an integer of 5-12, and more preferably N is an integer of 5-10.

[0058] In the present invention, α-olefin refers to an olefin compound in which the carbon-carbon double bond is located at the end of the molecular chain, and straight chain refers to a compound in which no branching structure exists in the molecule.

[0059] According to a preferred embodiment of the present application, the C N The linear alpha olefin is 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene or 1-nonene.

[0060] According to another embodiment of the present application, in the method of the present invention, step 1 (hydroformylation step) is first performed, in which C N Under the catalytic action of the first catalyst, the linear alpha olefin undergoes a hydroformylation reaction with a mixture of CO and H2 to generate C N+1 Aldehyde (target product is a linear C N+1 For example, Figure 1 In the embodiment shown, 1-octene undergoes hydroformylation to generate 1-nonanal. Next, step 2 (reduction step) is performed, in which the C N+1 The aldehyde reacts with hydrogen under the catalytic action of the second catalyst and is reduced to generate C N+1 Alcohol (target product is a straight chain C N+1alcohol, and the hydroxyl group is attached to the α-carbon). For example, Figure 1 In the embodiment shown, in the reduction step, nonanal undergoes a reduction reaction to generate 1-nonanol. Then, step three (dehydration step) is performed, in which the C N+1 The alcohol is dehydrated under the catalytic action of the third catalyst to generate C N+1 Olefins (target products are linear C N+1 olefins, and the double bond is located at the end of the molecule). For example, Figure 1 In the embodiment shown, in the dehydration step, 1-nonanol undergoes a dehydration reaction to produce 1-nonene.

[0061] According to one embodiment of the present application, the reduction reaction in step 1 can be carried out in a high-pressure reactor, in which the raw material C N The olefin, the first catalyst, CO, H2 and optionally a solvent and / or other reaction aids (if necessary) are mixed and contacted with each other to cause the desired hydroformylation reaction to occur.

[0062] According to one embodiment of the present application, the first catalyst used in the hydroformylation reaction contains a metal element, a first organic ligand, and a CO ligand, and the first catalyst may also optionally contain a second organic ligand. According to one embodiment of the present application, the first catalyst does not contain a second organic ligand and only contains the metal element, the first organic ligand, and the CO ligand. According to another embodiment of the present application, the first catalyst contains the metal element, the first organic ligand, the second organic ligand, and the CO ligand.

[0063] According to another embodiment of the present application, the metal element is selected from one or more of the following: rhodium, cobalt, iridium, ruthenium, iron, nickel, palladium, platinum, and osmium; preferably, the metal element in the first catalyst is rhodium. In the first catalyst, the metal element may be present as a zero-valent or positive-valent ion.

[0064] According to another embodiment of the present application, the first organic ligand has a structure shown in Formula I:

[0065]

[0066] According to one embodiment of the present application, in the formula I shown above, R1-R 10 Each of them is independently selected from: hydrogen, C1-C6 alkyl, C1-C6 alkoxy, C6-C16 aryl, amino, halogen; preferably R1-R 10 Each of R1-R2 is independently selected from the group consisting of hydrogen, C1-C4 alkyl, C1-C4 alkoxy, C6-C12 aryl, amino, and halogen; more preferably, R1-R10 Each of them is independently selected from the group consisting of hydrogen, C1-C3 alkyl, C1-C3 alkoxy, C6-C10 aryl, amino, and halogen.

[0067] In the present invention, "halogen" means fluorine, chlorine, bromine or iodine, preferably chlorine.

[0068] According to one embodiment of the present application, in Formula I shown above, A, B, C, and D respectively represent the number of substituents attached to the four benzene rings directly attached to the P atom at the bottom of Formula I, which can be independently 0, 1, 2, 3, 4, or 5. In other words, these benzene rings may have no substituents attached (that is, the benzene rings only have hydrogen atoms directly attached to the ring carbon atoms), or may have 1-5 substituents attached.

[0069] According to one embodiment of the present application, when one or more of A, B, C and D is not zero, R 11 -R 14 Each of them is independently selected from: C1-C6 alkyl, C1-C6 alkoxy; or R 11 -R 14 Each of them is independently selected from: C1-C4 alkyl, C1-C4 alkoxy; preferably R 11 -R 14 Each of them is independently selected from: C1-C2 alkyl, C1-C2 alkoxy.

[0070] According to an exemplary embodiment of the present application, the first organic ligand is selected from:

[0071]

[0072]

[0073] wherein t-Bu represents a tert-butyl group, and Me represents a methyl group.

[0074] According to another embodiment of the present application, the second organic ligand contained in the first catalyst has a structure shown in Formula II:

[0075]

[0076] In Formula II, P, Q, and R represent the number of substituents attached to the phenyl ring, which are each independently 1, 2, 3, 4, or 5. According to another embodiment of the present application, each of R15, R16, and R17 is independently selected from: C1-C6 alkyl, C1-C6 alkoxy; or each of R15, R16, and R17 is independently selected from: C1-C4 alkyl, C1-C4 alkoxy; preferably, each of R15, R16, and R17 is independently selected from: C1-C3 alkyl, C1-C3 alkoxy.

[0077] According to an exemplary embodiment of the present application, the second organic ligand is selected from:

[0078]

[0079] According to one embodiment of the present application, the first catalyst can be formed by mixing a metal source with a corresponding organic ligand. The metal source is a water-soluble salt of the above-mentioned metal, a compound soluble in an aqueous solvent or an organic solvent, examples of which include metal nitrates, chlorides, phosphates, sulfates, sulfites, alkoxides (such as metal methoxides, ethoxides, etc.), carboxylates (such as metal formates, acetates, citrates, etc.), sulfonates (such as metal methanesulfonates, p-toluenesulfonates, etc.), metal hydrides, metal coordination compounds, metal-coordination-hydrides, metal-coordination-salts, metal-coordination-hydride-salts, etc. The metal-coordinate-hydride mentioned above refers to a compound formed by a metal simultaneously combining with a hydrogen ion and a ligand; the metal-coordinate-salt refers to a compound formed by a metal simultaneously combining with a ligand and an anion (such as the anion used to form a salt mentioned above); and the metal-coordinate-hydride-salt refers to a compound formed by a metal simultaneously combining with a ligand, a hydrogen ion and an anion (such as the anion used to form a salt mentioned above).

[0080] Taking rhodium metal as an example, examples of rhodium metal sources may include: dicarbonyl rhodium acetylacetonate, Rh2O3, Rh4(CO) 12 、Rh6(CO) 16 , Rh(NO3)3, rhodium trichloride, triphenylphosphine rhodium chloride, dichloro(pentamethylcyclopentadienyl)rhodium(III) dimer, (1,5-cyclooctadiene)chlororhodium(I) dimer, rhodium acetate, rhodium acetylacetonate, rhodium dicarbonyl acetylacetonate, rhodium trifluoroacetylacetonate(III), rhodium acetylacetonate(1,5-cyclooctadiene), rhodium acetylacetonate carbonyl, rhodium carbonyl hydride, rhodium hydride, or a mixture thereof.

[0081] The carbonyl group in the first catalyst may be provided by a metal source or may be derived from other ligand compounds containing a carbonyl group.

[0082] In the present invention, the ratio of the components (metal element, first organic ligand, second organic ligand, CO ligand) in the first catalyst is calculated according to the molar amounts of these components added when preparing the catalyst.

[0083] According to one embodiment of the present application, in the process of preparing the first catalyst, the molar ratio of the added metal element to the first organic ligand is 1:0.5 to 1:5, for example, 1:0.6 to 1:4, or 1:0.8 to 1:3, or 1:0.9 to 1:2, or 1:1 to 1:1.15.

[0084] According to one embodiment of the present application, in the process of preparing the first catalyst, the molar ratio of the added metal element to the second organic ligand is 1:0 to 1:1, for example, 1:0, or greater than 1:0 to 1:1, or 1:0.05 to 1:0.8, or 1:0.06 to 1:0.5, or 1:0.08 to 1:0.3, or 1:0.1 to 1:0.2.

[0085] According to another embodiment of the present application, during the preparation of the first catalyst, the molar ratio of the added first organic ligand to the second organic ligand is 10:0 to 10:1, preferably 10:0.5 to 10:1.

[0086] According to a particularly preferred embodiment of the present application, the inventors have further unexpectedly discovered that the introduction of a second organic ligand into the first catalyst not only does not affect the reaction rate but also stabilizes the first organic ligand / rhodium catalyst, improving catalyst stability during the highly selective synthesis of n-aldols. This allows the catalyst to be more stable, have a longer service life in the catalytic reaction, and further improve catalytic performance.

[0087] According to another embodiment of the present application, during the preparation of the first catalyst, the molar ratio of the added metal element to the CO ligand is 1:1 to 1:3, for example, 1:1 to 1:2.

[0088] According to one embodiment of the present invention, when performing the hydroformylation reaction in step 1, the catalyst used can be dissolved or dispersed in the reaction liquid mixture in a homogeneous state, or can be in a heterogeneous state, such as suspended in the reaction liquid mixture.

[0089] According to another embodiment of the present application, based on the total weight of all materials (including liquid materials and solid materials) in the hydroformylation reactor, the catalyst content may be 30-10000 ppm (weight / weight ratio), for example, 35-5000 ppm, or 40-1000 ppm, or 45-500 ppm, or 50-200 ppm, or 55-100 ppm, or 60-70 ppm, or within the range of values obtained by combining any two of the above end values.

[0090] The hydroformylation reaction may also optionally use an organic solvent to help dissolve or disperse the first catalyst and the linear C N Examples of suitable organic solvents for α-olefin raw materials may include various alcohols, alkanes, alkenes, ethers, aldehydes, acetals, ketones, esters, amides, aromatic hydrocarbons, etc., provided that these solvents do not have any negative impact on the reaction and do not adversely affect the quality of the product. Specific examples of organic solvents include, for example, acetone, methyl ethyl ketone, ethyl acetate, diethyl phthalate, di(2-ethylhexyl) phthalate, toluene, nitrobenzene, tetrahydrofuran, sulfolane, etc. According to a non-limiting embodiment, based on the total weight of all materials in the hydroformylation reactor, the content of the organic solvent may be 0-99 wt%, such as 1-95 wt%, or 5-90 wt%, or 10-80 wt%, or 20-70 wt%, or 30-60 wt%, or 40-50 wt%. According to another embodiment of the present application, no additional organic solvent is used in the hydroformylation reaction, and the linear C N The α-olefin also functions as a solvent.

[0091] According to another embodiment of the present application, the total pressure of hydrogen and carbon monoxide in the hydroformylation reactor can be significantly lower than the pressure used in similar hydroformylation processes in the prior art. Specifically, the pressure (total pressure of CO and H2) used in similar hydroformylation processes in the prior art is usually as high as 5 bar (50 MPa), and in many cases even higher. The total pressure of hydrogen and carbon monoxide in the hydroformylation reactor used in the present invention is much lower, for example, 0.5-10 MPa, preferably 1-8 MPa, and more preferably 2-3 MPa. The molar ratio of hydrogen to carbon monoxide is 2:1 to 1:2, preferably 1.5:1 to 1:1.5, and more preferably 1:1. The reaction temperature of the hydroformylation is 65-120°C, for example, 70-110°C, or 75-100°C, or 80-90°C. The reaction time of the hydroformylation reaction is 20 minutes to 6 hours, for example, 1-4 hours.

[0092] In the hydroformylation reaction of the present invention, the raw material linear C N Excellent conversion of α-olefins and target product linear C N+1 Aldehyde selectivity: For example, the raw material conversion rate can be greater than 95%, and the target product selectivity can be 90-98%.

[0093] According to one embodiment of the present application, after the hydroformylation reaction in step 1, the product mixture is separated, specifically, CO and H2 gas are separated, and the liquid phase containing olefins (unreacted raw materials), aldehydes (products, and a small amount of by-products), solvents, and catalysts is purified (decompression, stripping, flash evaporation, etc.) to obtain the target product C N+1 The aldehyde is separated and then sent to the downstream step 2 for reduction. The solvent and catalyst are recycled back to the hydroformylation reactor, and the CO and H2 are pressurized and sent back to the hydroformylation reactor.

[0094] According to another embodiment of the present application, the reduction reaction in step 2 is carried out in a solid bed reactor (e.g., a tubular adiabatic bed reactor). Specifically, a reducing gas (e.g., hydrogen) and the linear C prepared in step 1 are introduced into the fixed bed reactor filled with the second catalyst. N+1 Aldehyde, so that the straight chain C N+1 The aldehyde is reduced to give C N+1 alcohol.

[0095] According to an independent embodiment of the present application, the second catalyst used in the step 2 comprises a carrier, a main catalytic element supported on the carrier, and an auxiliary element supported on the carrier. The carrier is selected from at least one of the following: alumina, silica, silicon-aluminum composite oxide, molecular sieve, zeolite, diatomaceous earth; preferably, the carrier is alumina. The main catalytic element in the second catalyst is selected from at least one of the following: Cu, Cr, Ni, Mg, Na; preferably, copper, nickel, magnesium, sodium, or any combination thereof. The auxiliary element in the second catalyst is selected from one or more of the following: Zn, Zr, Co, Ca, Sr, Ba; preferably, zinc and zirconium, or cobalt and calcium.

[0096] According to one embodiment of the present application, in the second catalyst, the weight ratio of the sum of the weight of the main catalytic element and the auxiliary element to the carrier is (main catalytic element + auxiliary element): carrier = 0.01:100 to 1.5:100; preferably 1.0:100.

[0097] According to another embodiment of the present application, in the second catalyst, the molar ratio of the main catalytic element to the auxiliary element is 1:0.2 to 1:5; preferably 1:0.4 to 1:3.

[0098] According to a preferred embodiment of the present application, the second catalyst comprises copper (main catalytic element), zinc and zirconium (promoter element) supported on an alumina carrier, wherein the molar ratio of Cu:Zn:Zr can be 1:(0.5-3):(0.5-3), for example, 1:(1-2):(1-1.5), or 1:1.5:1.

[0099] According to one embodiment of the present application, the second catalyst can be prepared by a conventional impregnation method, a coprecipitation method, a solid mixing method, or an equal volume impregnation method. According to a preferred embodiment of the present application, the second catalyst is prepared by an equal volume impregnation method, that is, the support is impregnated with a solution containing the desired metal ions, and then the liquid and solid are dried together and heat-treated to obtain the second catalyst. The second catalyst can be heat-treated and / or reduced as needed before use.

[0100] According to a specific embodiment of the present application, the reaction temperature of the reduction reaction in step 2 is 180-250°C, such as 190-220°C, or 200-210°C. According to a specific embodiment of the present application, the reaction pressure (hydrogen pressure) in the reduction range of step 2 is 1-5MPa, such as 2.5-4MPa, or 3-3.5MPa. According to a specific embodiment of the present application, the linear C N+1 Aldehyde for 0.1-1.5 hours -1 The feed space velocity is preferably 0.5-1.0 hours -1 According to another embodiment of the present application, the hydrogen and linear C N+1 The molar ratio of aldehyde is 1:1 to 3:1.

[0101] According to one embodiment of the present application, the linear C N+1 Alcohol is also a high-value product, and a portion of the linear C N+1 The alcohol is collected directly as the product without further proceeding to step 3; only the remaining linear C N+1 The alcohol is transported to step three to synthesize the linear C N+1 α-olefins.

[0102] According to another embodiment of the present application, the dehydration reaction in step 3 is carried out in a solid bed reactor. Specifically, the linear C prepared in step 2 is introduced into a fixed bed reactor filled with a third catalyst. N+1 alcohol, so that the straight chain C N+1 The alcohol undergoes dehydration to obtain a straight-chain C N+1 α-olefins.

[0103] According to an independent embodiment of the present application, the third catalyst used in step 3 can be alumina (e.g., α-alumina, which can be activated with water, acid, etc.) or a supported catalyst. The supported catalyst comprises a carrier and a metal element supported on the carrier. The carrier is selected from at least one of the following: alumina, silicon-aluminum composite oxide, molecular sieve, zeolite, and heteropolyacid; preferably, the carrier is alumina. The metal element in the third catalyst is selected from at least one of the following: barium, vanadium, aluminum, and tungsten; preferably, barium.

[0104] According to one embodiment of the present application, in the third catalyst, the weight ratio of the carrier to the metal element is carrier:metal element=100:0.03 to 100:1; preferably 100:0.5.

[0105] According to one embodiment of the present application, the third catalyst can be prepared by a conventional impregnation method, a coprecipitation method, a solid mixing method, or an equal volume impregnation method. According to a preferred embodiment of the present application, the second catalyst is prepared by an equal volume impregnation method and can be subjected to a heat treatment and / or reduction treatment as needed before use.

[0106] According to a specific embodiment of the present application, the reaction temperature of the dehydration reaction in step 3 is 260-330°C, such as 280-310°C, or 290-300°C. According to a specific embodiment of the present application, the reaction pressure of the dehydration range in step 3 is 0.12-0.60MPa, such as 0.20-0.50Mpa, or 0.30-0.40MPa. According to a specific embodiment of the present application, the linear C N+1 Alcohol for 0.05-1 hour -1 The feed space velocity is preferably 0.3-0.5 hours -1 .

[0107] The method of the present invention can achieve excellent overall product selectivity, such as linear C N+1 The selectivity of alcohol can be as high as 98.5%, while the linear C N+1 The selectivity to α-olefins can be as high as 85%.

[0108] Example

[0109] The following examples specifically illustrate preferred embodiments of the present invention, but it should be understood that the scope of protection of the present invention is not limited thereto. The first organic ligand used in the following examples has the structure shown in Formula a, the second ligand has the structure shown in Formula b, and the triphenylphosphine used in the comparative example has the structure shown in Formula c. All three were purchased from Shanghai Sinopharm Reagent Co., Ltd.; dicarbonyl acetylacetonate rhodium was purchased from Hangzhou Kaida Co., Ltd.; all other chemical reagents were of analytical grade; and the synthesis gas used in the following examples was a mixture of hydrogen and carbon monoxide in a molar ratio of 1:1.

[0110]

[0111] Example 1

[0112] In this example, the hydroformylation reaction of step 1 of the process of the present invention was carried out.

[0113] Specifically, first, 0.058 grams of dicarbonyl acetylacetonate rhodium and 0.32 grams of the first organic ligand, and 100 grams of 1-octene were added to a stainless steel autoclave with a volume of 250 ml. The autoclave was closed, and the atmosphere in the autoclave was replaced 3 times with synthesis gas. The heating device was started, the temperature of the reactor was heated to 80°C and maintained at this temperature, and then synthesis gas was charged into the reactor to 1.5 MPa. During the reaction, synthesis gas was continuously added to the reactor through a flow meter so that the pressure in the reactor was maintained at about 1.5 MPa. The reaction continued for 4.5 hours, and then the heating was stopped so that the temperature of the reactor was reduced to room temperature. The reaction solution was removed from the reactor and the reaction solution composition was analyzed using gas chromatography ( Figure 2 ), using nuclear magnetic resonance 31 P spectrum analysis of the catalyst in the reaction solution ( Figure 3 ).like Figure 2 As shown in the figure, the reaction liquid mainly contains the target product n-nonanal (1-nonanal), and there are also small by-product (2-methyloctanal) peaks, unreacted raw material (1-octene) peaks and other impurity olefin peaks contained in the raw material. According to the gas chromatography results, the conversion rate of 1-octene is 95%, the nonanal selectivity is 97.5%, of which n-nonanal accounts for 95%. Figure 3 NMR 31 The P spectrum shows a characteristic peak at -17.2 ppm for the first ligand, peaks at 26.5 ppm and 24.5 ppm for the rhodium / first ligand catalyst, and a peak at -22.4 ppm for the first ligand's decomposition product. These characterization results demonstrate that while excellent catalytic performance can be achieved in this example, some decomposition of the first ligand occurs during the reaction.

[0114] Example 2

[0115] In this example, the hydroformylation reaction of step 1 of the process of the present invention was carried out.

[0116] Specifically, 0.058 g of rhodium dicarbonyl acetylacetonate, 0.32 g of a first organic ligand, 0.3 g of a second ligand, and 100 g of 1-octene were first added to a 250 ml stainless steel autoclave. The autoclave was sealed, and the atmosphere was replaced three times with synthesis gas. The heating device was then activated to heat the autoclave to 80°C and maintain this temperature. Synthesis gas was then introduced into the autoclave to a pressure of 1.5 MPa. During the reaction, synthesis gas was continuously added to the autoclave via a flowmeter to maintain the pressure at approximately 1.5 MPa. The reaction was continued for 4.5 hours, after which heating was stopped and the autoclave temperature was allowed to cool to room temperature. The reaction liquid was removed from the autoclave, and the liquid phase composition was analyzed using gas chromatography. Peak area integration of the gas chromatogram determined that the 1-octene conversion was 96%, the nonanal selectivity was 97.8%, and n-nonanal accounted for 95.2%. The above characterization results show that compared with Example 1, Example 2 can further improve the catalytic reaction effect by further introducing a second organic ligand into the catalyst.

[0117] Example 3

[0118] This Example 3 investigates the stability of the catalysts used in Examples 1 and 2 under continuous heating conditions.

[0119] In Example 3, the steps of Example 1 and Example 2 were repeated, and the obtained reaction solution was heated at 90° C. for one week under a nitrogen atmosphere, and then samples were taken for use. 31 The PNMR spectrum was characterized and the results were as follows: Figure 4 and Figure 5 shown.

[0120] Depend on Figure 4 It can be seen that after the reaction solution obtained in Example 1 was heated at 90°C for one week under a nitrogen atmosphere, the characteristic peaks at 26.5 ppm and 24.5 ppm remained stable, but the characteristic peak at -17.2 ppm had completely disappeared. This demonstrates that in the absence of a second organic ligand in the catalyst, significant catalyst decomposition and loss occurred during the prolonged heating process.

[0121] Figure 5The results show that after heating the reaction solution obtained in Example 2 at 90°C for one week under a nitrogen atmosphere, not only the characteristic peaks at 26.5 ppm and 24.5 ppm remained stable, but also the characteristic peak of the free first ligand at -17.2 ppm remained stable. This demonstrates that when the catalyst contains a second organic ligand, the catalyst exhibits excellent stability during the prolonged heating process, without significant decomposition or loss.

[0122] Comparative Example 1

[0123] Specifically, 0.058 grams of dicarbonyl acetylacetonate rhodium, 0.32 grams of the first organic ligand, 0.3 grams of triphenylphosphine, and 100 grams of 1-octene were first added to a stainless steel autoclave with a volume of 250 ml. The triphenylphosphine used here is similar to the compound structure of Formula 2 used in Example 2, but is not within the scope of protection of the present invention. The autoclave is closed, and after the atmosphere in the autoclave is replaced 3 times with synthesis gas, the heating device is started, the temperature of the reactor is heated to 80°C and maintained at this temperature, and then synthesis gas is charged into the reactor to 1.5 MPa. During the reaction, synthesis gas is continuously added to the reactor through a flow meter so that the pressure in the reactor is maintained at about 1.5 MPa. The reaction is continued for 4.5 hours, and then heating is stopped so that the temperature of the reactor is reduced to room temperature. The reaction solution is removed from the reactor and the liquid phase composition is analyzed using gas chromatography. By integrating the peak area of the gas chromatogram, it was determined that the 1-octene conversion was 66%, the nonanal selectivity was 98.9%, of which n-nonanal accounted for 85.3%.

[0124] Example 4

[0125] In this example, the reaction liquid prepared in Example 2 was further purified. Specifically, the nonanal mixture was introduced into a distillation column, where unreacted olefins, alkanes, and other light components were first removed at a pressure of 2 kPa and a tower top temperature of 30°C. The mixture was then transferred to a de-weighting column, where n-nonanal with a purity of 99.9% was obtained at the tower top at a pressure of 2 kPa and a tower top temperature of 85°C.

[0126] Example 5

[0127] In this example, the nonanal prepared in Example 4 was subjected to hydrogenation reduction.

[0128] The second catalyst was prepared by the following steps: 90 g of nickel nitrate hexahydrate, 17 g of magnesium nitrate hexahydrate, 0.5 g of cobalt nitrate hexahydrate, and 3 g of calcium nitrate tetrahydrate were weighed and added to 1 L of deionized water to form a solution. The mixture was heated to 80 ° C in a three-necked flask under stirring, and 800 g of 10% anhydrous sodium carbonate solution was added dropwise to allow the materials in the flask to undergo a coprecipitation reaction. After the addition was completed, stirring and aging was continued at 80 ° C for 1 hour. Subsequently, 500 g of 25% silica sol solution was added, and after continuing to stir for 1 hour, the mixture was filtered, washed, dried, and calcined at 500 ° C for 2 hours to obtain a hydrogenation catalyst precursor (the above reagent raw materials were all purchased from Shanghai Sinopharm Reagent Co., Ltd.). In the hydrogenation micro-reactor evaluation device, 7.3 g of hydrogenation catalyst precursor was added to the middle of the hydrogenation bed, and the bed was filled with quartz sand above and below. The reduction conditions are as follows: maintain at 30°C for 120 minutes, increase to 150°C at 1°C / min, maintain at 150°C for 240 minutes (4 hours), maintain at 150°C for 100 minutes, increase to 250°C at 1°C / min, maintain at 250°C for 120 minutes (2 hours), and then decrease from 250°C to the reaction temperature of 160°C. The reaction can then be used for hydrogenation reduction reaction.

[0129] The hydrogenation reaction steps and conditions are as follows: n-nonanal obtained in Example 4 is mixed with n-nonanol to prepare a 5% (volume concentration) n-nonanal / n-nonanol mixed solution. The mixed solution is preheated to 120° C. and then transferred together with hydrogen to the above-mentioned reaction apparatus filled with the above-mentioned catalyst. The hydrogen / aldehyde molar ratio is 1.05:1, the reaction pressure is 2.5 MPa, and the liquid hourly space velocity (based on the n-nonanal / n-nonanol mixed solution) is 0.6 h. -1 .

[0130] The materials produced by the hydrogenation reaction were characterized by gas chromatography, and the conversion rate of n-nonanal was measured to be 99% and the selectivity of n-nonanol was 99.2%.

[0131] The liquid phase after the reaction was distilled and purified through light and heavy degassing distillation towers. The light degassing tower pressure was 15 kPa and the bottom temperature was 160°C. The heavy degassing tower pressure was 10 kPa and the bottom temperature was 160°C. 20 theoretical plates were used, using M252Y packing, to obtain n-nonanol with a purity of 99.9%.

[0132] Example 6

[0133] In Example 6, the n-nonanol prepared in Example 5 was subjected to catalytic dehydration to prepare the target product α-nonene.

[0134] Specifically, the dehydration reaction uses a hydrothermally activated α-Al2O3 catalyst. Unactivated α-Al2O3 was purchased from Shanghai Sinopharm Reagent, and the catalyst particle size was between 10-80 mesh. Before the formal feeding reaction, 4 grams of α-Al2O3 was loaded into a fixed bed reactor and calcined at 500°C for 4 hours under an air atmosphere. After the calcination, nitrogen was introduced while the temperature was lowered to 100°C. Under the condition of maintaining the pressure at 0.5MPa with N2, the reactor was heated at a space velocity of 0.5h. -1 Deionized water was introduced at a feed rate of 100 mL / min, with the pressure controlled by a tail gas regulating valve. After continuously introducing deionized water for 5 hours, the temperature was raised again under a nitrogen atmosphere at a controlled heating rate of 2°C / min and a nitrogen introduction rate of 500 ml / h. After 4 hours of continuous introduction, n-nonanol was introduced at a feed rate of 15 ml / h, maintaining the pressure at 0.5 MPa through the tail gas regulating valve. The liquid product was analyzed by gas chromatography, revealing a n-nonanol conversion of 95.5% and a n-nonene selectivity of 96.8%.

[0135] The product was post-treated to obtain α-nonene, and the total yield of α-nonene was calculated to be 81.15%.

[0136] Comparative Example 2

[0137] The steps of Examples 4-6 above were repeated for the product obtained in Comparative Example 1 to obtain α-nonene. The total yield of α-nonene was calculated to be 50.5%.

Claims

1. A kind of N α-olefin preparation C N+1 A process for producing alpha-olefins, the process comprising the steps of: Step 1: In the presence of a first catalyst, the C N α-olefins react with carbon monoxide and hydrogen to form C N+1 aldehyde; Step 2: C obtained in step 1 N+1 Aldehyde is reduced to obtain C N+1 alcohol; Step 3: C obtained in step 2 N+1 At least a portion of the alcohol is dehydrated to obtain the C N+1 α-olefins; Among them C N Indicates that the molecule contains N carbon atoms, C N+1 Indicates that the molecule contains N+1 carbon atoms, where N is an integer from 3 to 16; The first catalyst contains a metal element, a first organic ligand and a CO ligand, and the first catalyst optionally further contains a second organic ligand; The metal element is selected from one or more of the following: rhodium, cobalt, iridium, ruthenium, iron, nickel, palladium, platinum, and osmium; The first organic ligand has a structure shown in Formula I: In Formula I, R1-R 10 Each of them is independently selected from the group consisting of hydrogen, C1-C6 alkyl, C1-C6 alkoxy, C6-C16 aryl, amino, and halogen; R 11 -R 14 Each of the groups is independently selected from the group consisting of C1-C6 alkyl, C1-C6 alkoxy; A, B, C and D are each independently 0-5; The second organic ligand is a triphenylphosphine derivative having the structure shown in Formula II: In Formula II, each of R15, R16 and R17 is independently selected from the group consisting of C1-C6 alkyl and C1-C6 alkoxy; and P, Q and R are independently 1-5.

2. The method according to claim 1, characterized in that In the first catalyst, the molar ratio of the metal element to the first organic ligand is 1:0.5 to 1:5; and the molar ratio of the metal element to the CO ligand is 1:1 to 1:

3.

3. The method according to claim 2, characterized in that In the first catalyst, the molar ratio of the metal element to the second organic ligand is 1:0 to 1:1; and the molar ratio of the first organic ligand to the second organic ligand is 10:0 to 10:

1.

4. The method according to claim 1, wherein The C N α-olefins, C N+1 Aldehyde, C N+1 Alcohol and C N+1 α-olefins all have a straight chain structure and do not include a branched structure in the molecule. N+1 The aldehyde group of aldehyde and C N+1 The hydroxyl groups of alcohols are located at the ends of their molecular chains.

5. The method according to claim 4, characterized in that The C N The α-olefin is 1-butene, 1-pentene, 1-hexene, 1-heptene, 1-octene or 1-nonene.

6. The method according to claim 1, characterized in that In the step 1, the molar ratio of hydrogen to carbon monoxide is 2:1 to 1:2, the total pressure of hydrogen and carbon monoxide is 0.5-5.0 MPaG, the reaction temperature is 65-120° C., and the reaction time is 20 minutes to 6 hours.

7. The method according to claim 1, characterized in that In the step 2, the C obtained in step 1 is reacted with the catalyst in the presence of a second catalyst. N+1 Aldehyde reacts with hydrogen to obtain C N+1 alcohol; The second catalyst comprises a carrier, a main catalytic element supported on the carrier, and a promoter element supported on the carrier; The carrier is selected from at least one of the following: alumina, silicon oxide, silicon-aluminum composite oxide, molecular sieve, zeolite, and diatomaceous earth; The main catalytic element is selected from at least one of the following: Cu, Cr, Ni, Mg, and Na; The auxiliary element is selected from one or more of the following: Zn, Zr, Co, Ca, Sr, Ba; The weight ratio of the sum of the weight of the main catalytic element and the auxiliary element to the carrier is (main catalytic element+auxiliary element):carrier=0.01:100 to 1.5:100; The molar ratio of the main catalytic element to the auxiliary element is 1:0.2 to 1:

5.

8. The method according to claim 1, characterized in that In the step 2, the reduction reaction temperature is 180-250°C, the hydrogen pressure is 1-5MPa, C N+1 Aldehyde for 0.1-1.5 hours -1 Feed at a space velocity of .

9. The method according to claim 1, characterized in that In the step 3, the C obtained in step 2 is reacted with the catalyst in the presence of a third catalyst. N+1 The alcohol is dehydrated to obtain the C N+1 α-olefins; The third catalyst is alumina or a supported catalyst, wherein the supported catalyst comprises a carrier and a metal element supported on the carrier; The carrier is selected from at least one of the following: alumina, silicon-aluminum composite oxide, molecular sieve, and zeolite; The metal element is selected from at least one of the following: barium, vanadium, aluminum, and tungsten; The weight ratio of the metal element to the carrier is 0.03:100 to 1:

100.

10. The method according to claim 1, characterized in that In the step 3, the reaction temperature is 260-330°C, the reaction pressure is 0.12-0.6 MPa, C N+1 Alcohol for 0.05-1 hour -1 Feed at a space velocity of .

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