A method for directly converting olefins and syngas into alcohols

Abstract

The present invention belongs to the direct conversion of olefins and syngas to alcohols, and particularly relates to a method for the direct conversion of olefins and syngas to alcohols. A catalyst therein consists of a metal active component A, a metal active component B and an organic ligand polymer. The metal active component A has the catalytic performance for olefin hydroformylation and is selected from one or more of metals Rh, Co, Ir, Ru or Fe; the metal active component B has the catalytic performance for aldehyde hydrogenation and is selected from one or more of metals Pd, Pt, Cu or Ni; the organic ligand polymer is a porous polymer formed by solvothermal polymerization of an organic P ligand containing vinyl groups. By means of a bifunctional catalyst in the method of the present invention, the raw material conversion rate and the target product yield in the reaction process are excellent. The olefin conversion rate can reach 95%, and the selectivity for higher alcohols is greater than 90%. The invention provides a method for directly converting olefins and syngas to high-value alcohol chemicals, which has broad industrial application prospects.

Description

Technical Field

[0001] The present invention relates to a method for directly converting olefins and syngas into alcohols, belonging to the technical field of heterogeneous catalysis. Background Art

[0002] Hydroformylation is a reaction in which an olefin reacts with syngas to form an aldehyde with one more carbon than the starting olefin. It is one of the most important industrial homogeneous catalytic reactions. The hydroformylation reaction is a typical atom-economic reaction, and the research on its catalytic process and catalysts has a history of more than 80 years. Currently, more than 22 million tons of aldehydes and alcohols are produced annually worldwide using olefin hydroformylation technology. This reaction can convert the starting olefin into an aldehyde under relatively mild conditions. However, in most cases, the product aldehyde is often not the final product. Utilizing the reactivity of the aldehyde group, it can be further converted into more valuable fine chemicals. For example, the most industrially applicable olefin hydroformylation-hydrogenation tandem reaction can directly obtain the target product alcohol in a "one-pot" reaction. The olefin hydroformylation-hydrogenation tandem reaction can avoid the separation and purification steps of intermediate products, effectively reduce the generation of by-products; at the same time, it can shorten the reaction process flow, effectively reduce the reaction energy consumption, thereby achieving the efficient and economic synthesis of alcohol products.

[0003] Homogeneous catalytic systems have high catalytic activity and selectivity for target products under mild reaction conditions, but the separation of the catalyst from the reaction materials is difficult, which hinders the large-scale industrial application of homogeneous catalytic systems. The biggest advantage of heterogeneous catalysis compared to homogeneous catalysis is that the catalyst is easily separated from the reaction materials. The main problems are harsh reaction conditions and relatively low reaction activity, etc. Developing a new type of heterogeneous catalyst that has both the advantages of easy separation of the catalyst from the reaction materials in heterogeneous catalysis and high reaction activity and mild reaction conditions in homogeneous catalysis is the direction that researchers have been working hard on.

[0004] At present, there are many research reports on the tandem hydroformylation-hydrogenation reaction of olefins. Patent CN107866282A discloses the application of a class of nitrogen-phosphorus ligands in the tandem hydroformylation-hydrogenation reaction of olefins. The nitrogen-phosphorus ligands disclosed in this invention have bifunctional characteristics. They have a phosphine ligand group that coordinates with transition metals rhodium or ruthenium, and a secondary amine or imine nitrogen-containing group that acts with protonic acid, and can achieve the tandem hydroformylation-hydrogenation reaction of olefins. However, the synthesis route of this nitrogen-phosphorus ligand is complex and the raw material price is relatively expensive. Nozaki et al. (J. Am. Chem. Soc. 2013, 135, 17393-17400) disclosed a composite catalyst system combining a Rh-bisphosphite complex system and a Ru-Shvo catalytic system, which can achieve the direct conversion of long-chain olefins to alcohols with one more carbon number. The reaction efficiency of this catalytic system is relatively high, but both catalysts are precious metals and the prices of related ligands are also very expensive. In summary, the above research results mainly use catalysts composed of precious metals and complex phosphine-nitrogen ligands to catalyze the tandem hydroformylation-hydrogenation reaction of olefins. The catalyst preparation process is cumbersome and expensive. Especially, the preparation synthesis route of complex phosphine-nitrogen ligands is cumbersome, the raw material price is expensive and the yield is low; moreover, the homogeneous catalytic process is not conducive to large-scale industrial applications.

[0005] Aiming at the deficiencies of the prior art, there is an urgent need for a catalytic system with a simple preparation method and low price and a heterogeneous catalytic reaction process to achieve the one-step direct conversion of olefins and syngas into product alcohols. In view of the characteristic that the tandem hydroformylation reaction of olefins is the coupling of two chemical reaction processes, the catalytic system required for catalyzing the tandem hydroformylation reaction of olefins needs to have hydroformylation-hydrogenation dual catalytic active centers in order to efficiently achieve the tandem hydroformylation-hydrogenation reaction of olefins. The catalyst system disclosed in this invention has hydroformylation and hydrogenation dual active centers. Under the action of the bifunctional catalyst, the one-step direct production of product alcohols from olefins and syngas is realized. Summary of the Invention

[0006] In order to solve the above problems, the purpose of this invention is to provide a method for directly converting olefins and syngas into alcohols. By using the above bifunctional catalyst, the one-step conversion of olefins and syngas can directly prepare high-value alcohol products.

[0007] To this end, the present invention provides a method for directly converting olefins and syngas into alcohols, which is characterized in that, in the presence of a catalyst, olefins and syngas are directly converted in one step to produce product alcohols; wherein the catalyst is composed of a metal active component A, a metal active component B and an organic ligand polymer, the metal active component A has the catalytic performance of olefin hydroformylation and is selected from one or more of metals Rh, Co, Ir, Ru or Fe; the metal active component B has the catalytic performance of aldehyde hydrogenation and is selected from one or more of metals Pd, Pt, Cu or Ni; the organic ligand polymer is a porous polymer formed by solvothermal polymerization of an organic P ligand containing vinyl groups.

[0008] In one embodiment, the reaction conditions for the direct conversion of olefins and syngas into alcohols are as follows: the reaction temperature is 293 - 573 K (preferably 353 - 453 K), the reaction pressure is 0.1 - 20 MPa (preferably 0.5 - 5 MPa), the syngas volumetric space velocity is 100 - 20000 h -1 (preferably 500 - 8000 h -1 ), and the molar ratio of the raw material olefins to syngas is 0.01:1 - 20:1 (preferably 0.1:1 - 10:1).

[0009] In one embodiment, the olefins refer to one or more of linear olefins of C 3-20 or aromatic olefins of C 6-20 ; the syngas source is a process for producing syngas using one or more of natural gas, coal, oilfield gas, coalbed methane or hydrocarbons as raw materials, and the main components of the syngas are H2 and CO, the volume contents of H2 and CO are 20% - 100% (preferably 80% - 100%), and the H2 / CO volume ratio is 0.5 - 20.0 (preferably 1.0 - 15.0).

[0010] In one embodiment, the metal active component A and the active component B are supported on the polymer, the metal active component A accounts for 0.05% - 20.0% of the total weight of the catalyst, preferably 0.1% - 5%; the metal active component B accounts for 0.05% - 20.0% of the total weight of the catalyst, preferably 0.5% - 10%.

[0011] In one embodiment, the organic ligand polymer is a polymer formed by solvothermal polymerization of an organic P ligand containing vinyl groups, and the organic P ligand containing vinyl groups is selected from one or more of the following:

[0012]

[0013] In one embodiment, the method includes:

[0014] a) 273 - 473 K (preferably 293 - 423 K), in a solvent containing a vinyl-functionalized P ligand, add a radical initiator and stir for 0.5 - 50 h (preferably 1 - 20 h);

[0015] b) At 273 - 473 K (preferably 323 - 423 K), let the mixed solution from step a) stand for 0.5 - 100 h (preferably 5 - 50 h) for polymerization reaction. After the polymerization ends, remove the solvent to obtain an organophosphorus ligand polymer;

[0016] c) To load active components A and B, one of the following three methods can be used:

[0017] c1) Place the polymer from step b) in a solvent containing metal active component B, stir at 273 - 473 K (preferably 293 - 423 K) for 0.5 - 100 h (preferably 5 - 50 h), and remove the solvent under vacuum; after removing the solvent, place the above solid powder in a solvent containing metal active component A, stir at 273 - 473 K (preferably 293 - 423 K) for 0.5 - 100 h (preferably 5 - 50 h), and remove the solvent under vacuum; thus, a catalyst with polymer-supported metal active components A and B is obtained;

[0018] c2) Place the polymer from step b) in a solvent containing metal active component A, stir at 273 - 473 K (preferably 293 - 423 K) for 0.5 - 100 h (preferably 5 - 50 h), and remove the solvent under vacuum; after removing the solvent, place the above solid powder in a solvent containing metal active component B, stir at 273 - 473 K (preferably 293 - 423 K) for 0.5 - 100 h (preferably 5 - 50 h), and remove the solvent under vacuum; thus, a catalyst with polymer-supported metal active components A and B is obtained;

[0019] c3) Place the polymer from step b) in a solvent containing metal active components A and B, stir at 273 - 473 K (preferably 293 - 423 K) for 0.5 - 100 h (preferably 5 - 50 h), and remove the solvent under vacuum; thus, a catalyst with polymer-supported metal active components A and B is obtained.

[0020] In one embodiment, the solvents used in steps a) and c) of the above catalyst preparation method are one or more of benzene, toluene, tetrahydrofuran, methanol, ethanol, dichloromethane, dichloroethane, or deionized water; the radical initiator used in step a) is one or more of cyclohexanone peroxide, benzoyl peroxide, tert-butyl hydroperoxide, azobisisobutyronitrile, or azobisisoheptonitrile; the weight ratio of the radical initiator to the P ligand is 1:500 - 1:5 (preferably 1:100 - 1:10).

[0021] In a preferred embodiment, in step c) of the catalyst preparation method, it is preferred to prepare the catalyst by step c1).

[0022] In one embodiment, the reaction of directly converting olefins and syngas into alcohols is carried out in a continuous or batch manner, and the reactor is a fixed bed, trickle bed or autoclave reactor.

[0023] In one embodiment, when the reactor is a fixed bed or trickle bed, the reaction of directly converting olefins and syngas into alcohols is continuously carried out on the catalyst, and the generated liquid product continuously flows out of the reactor and is collected through a product collection tank; when the reactor is an autoclave reactor, the reaction of directly converting olefins and syngas into alcohols is carried out intermittently on the catalyst, and the generated liquid product is obtained by separating from the catalyst through filtration; the above-obtained liquid product is further processed by distillation, flash evaporation or extraction to obtain a high-purity alcohol product.

[0024] The beneficial effects of the present invention include but are not limited to the following: 1) Compared with the existing industrial application of hydroformylation reaction technology, due to the use of a novel heterogeneous catalyst, the separation cost of the catalyst from the reactants and products is reduced, which is suitable for actual industrial production; 2) The olefin hydroformylation-hydrogenation tandem reaction can avoid the separation and purification steps of intermediate products and effectively reduce the generation of by-products; 3) At the same time, the reaction process flow can be shortened, and the reaction energy consumption can be effectively reduced, so as to realize the efficient and economic synthesis of alcohol products. By using the method of the present invention, olefins and syngas can be directly converted into product alcohols in one step under the action of a heterogeneous catalyst, and this method has high economic value and broad application prospects. Detailed implementation mode

[0025] In order to better illustrate the catalyst preparation method and its application in the one-step conversion of olefins and syngas to directly prepare alcohol products, some examples of the preparation of catalyst samples and their application in the reaction process are given below, but the present invention is not limited to the listed examples. Unless otherwise specifically stated, the contents and percentages in this application are calculated by "mass".

[0026] Example 1

[0027] At room temperature, 1 g of tris(4-vinylphenyl) phosphite, 1 g of tris(4-vinylphenyl)phosphine and 0.05 g of azobisisobutyronitrile were dissolved in 20 ml of tetrahydrofuran solvent. After stirring for 1 h, the above mixed solution was polymerized at 120 °C for 24 h. After polymerization, the solvent was removed under reduced pressure to obtain a porous organic polymer containing a phosphine ligand. At room temperature, 0.24 g of Cu(OAc)2 and 2 g of the above-prepared polymer were weighed and added to 50 ml of ethanol solvent. After stirring for 24 h, the solvent was removed under reduced pressure to obtain solid powder a. At room temperature, 50.13 mg of Rh(acac)(CO)2 and 2 g of solid powder a were weighed and added to 50 ml of ethanol solvent. After stirring for 24 h, the solvent was removed under reduced pressure to obtain catalyst a.

[0028] 1 g of catalyst a was loaded into the middle of a tubular reactor, and quartz sand was filled at both ends. A mixed feed gas (C2H4:CO:H2 = 1:1:8) was introduced, and the mixed feed gas was fed directly in the form of a gas. At 393 K, 1 MPa, and a mixed feed gas space velocity of 8000 h -1 The reaction was carried out under the conditions. The obtained liquid-phase product was analyzed by HP-7890N gas chromatography, and the internal standard method was used with anhydrous ethanol as the internal standard for analysis and calculation. The reaction results are listed in Table 1.

[0029] Example 2

[0030] At room temperature, 1 g of tris(4-vinylphenyl) phosphite, 1 g of tris(4-vinylphenyl)phosphine and 0.05 g of azobisisobutyronitrile were dissolved in 20 ml of tetrahydrofuran solvent. After stirring for 1 h, the above mixed solution was polymerized at 120 °C for 24 h. After polymerization, the solvent was removed under reduced pressure to obtain a porous organic polymer containing a phosphine ligand. At room temperature, 50.13 mg of Rh(acac)(CO)2 and 2 g of the above-prepared polymer were weighed and added to 50 ml of ethanol solvent. After stirring for 24 h, the solvent was removed under reduced pressure to obtain solid powder b. At room temperature, 0.24 g of Cu(OAc)2 and 2 g of solid powder b were weighed and added to 50 ml of ethanol solvent. After stirring for 24 h, the solvent was removed under reduced pressure to obtain catalyst b.

[0031] 1 g of catalyst b was loaded into the middle of a tubular reactor, and quartz sand was filled at both ends. A mixed feed gas (C2H4:CO:H2 = 1:1:8) was introduced, and the mixed feed gas was fed directly in the form of a gas. At 393 K, 1 MPa, and a mixed feed gas space velocity of 8000 h -1 The reaction was carried out under the conditions. The obtained liquid-phase product was analyzed by HP-7890N gas chromatography, and the internal standard method was used with anhydrous ethanol as the internal standard for analysis and calculation. The reaction results are listed in Table 1.

[0032] Example 3

[0033] At room temperature, 1 g of tris(4-vinylphenyl) phosphite, 1 g of tris(4-vinylphenyl)phosphine and 0.05 g of azobisisobutyronitrile were dissolved in 20 ml of tetrahydrofuran solvent. After stirring for 1 h, the above mixed solution was polymerized at 120 °C for 24 h. After polymerization, the solvent was removed under reduced pressure to obtain a porous organic polymer containing a phosphine ligand. At room temperature, 50.13 mg of Rh(acac)(CO)2, 0.24 g of Cu(OAc)2 and 2 g of the above-prepared polymer were weighed and added to 50 ml of ethanol solvent. After stirring for 24 h, the solvent was removed under reduced pressure to obtain catalyst c.

[0034] 1 g of catalyst c was loaded into the middle of a tubular reactor, and quartz sand was filled at both ends. A mixed feed gas (C2H4:CO:H2 = 1:1:8) was introduced, and the mixed feed gas was directly fed in the form of a gas. At 393 K and 1 MPa, the space velocity of the mixed feed gas was 8000 h -1 The reaction was carried out under the conditions. The obtained liquid-phase products were analyzed by HP-7890N gas chromatography, and calculated by the internal standard method using anhydrous ethanol as the internal standard. The reaction results are listed in Table 1.

[0035] Example 4

[0036] In Example 4, except that 2 g of tris(4-vinylphenyl)phosphine was weighed to replace 1 g of tris(4-vinylphenyl) phosphite and 1 g of tris(4-vinylphenyl)phosphine under the reaction evaluation conditions, other procedures were the same as those in Example 1. The reaction results are listed in Table 1.

[0037] Example 5

[0038] In Example 5, except that 2 g of tris(4-vinylphenyl) phosphite was weighed to replace 1 g of tris(4-vinylphenyl) phosphite and 1 g of tris(4-vinylphenyl)phosphine, other procedures were the same as those in Example 1. The reaction results are listed in Table 1.

[0039] Example 6

[0040] In Example 6, except that 0.12 g of Pd(acac)2 was weighed and added to the solvent to replace 0.24 g of Cu(OAc)2 added to the solvent, other procedures were the same as those in Example 1. The reaction results are listed in Table 1.

[0041] Example 7

[0042] In Example 7, except that 100.26 mg of Rh(acac)(CO)2 was weighed and added to the solvent to replace 50.13 mg of Rh(acac)(CO)2 added to the solvent, other procedures were the same as those in Example 1. The reaction results are listed in Table 1.

[0043] Example 8

[0044] In Example 8, except for the reaction conditions of 408K, 3MPa, and a mixed feed gas space velocity of 8000 h -1 replacing the reaction conditions of 393K, 1MPa, and a mixed feed gas space velocity of 8000 h -1 , other processes are the same as those in Example 1. The reaction results are listed in Table 1.

[0045] Example 9

[0046] In Example 9, except that the olefin C3H6 in the mixed feed gas replaces the olefin C2H4 in the mixed feed gas, and the composition change of the mixed gas remains unchanged. After replacement, the composition of the mixed feed gas is C3H6:CO:H2 = 1:1:8. Other processes are the same as those in Example 1. The reaction results are listed in Table 1.

[0047] Example 10

[0048] In Example 10, except that the olefin C8H 16 replaces the olefin C2H4 in the mixed feed gas, and the composition change of the mixed gas remains unchanged. After replacement, the composition of the mixed feed gas is a molar ratio of C8H 16 :CO:H2 = 1:1:8. The liquid olefin C8H 16 is input into the reaction system through a high-pressure pump, and the syngas enters the reaction system in gas form. Other processes are the same as those in Example 1. The reaction results are listed in Table 1.

[0049] Table 1. Reaction results of direct conversion of olefins and syngas to alcohols

[0050]

[0051] Examples 1 - 10 give the experimental data of the direct conversion of olefins and syngas to alcohol products. The differences in the catalysts prepared in Examples 1 - 3 lie in the different ways of loading the active components A and B, and the other reaction condition parameters are the same. In Example 1, when the active component B is loaded first and then the active component A is loaded, the olefin conversion rate is 93.5% and the alcohol selectivity is 91.6%; in Example 2, when the active component A is loaded first and then the active component B is loaded, the olefin conversion rate is 68.5% and the alcohol selectivity is 76.2%; in Example 3, when the active components A and B are loaded simultaneously, the olefin conversion rate is 79.3% and the alcohol selectivity is 81.7%. The results of Examples 1 - 3 show that when the method of loading the active component B first and then the active component A is used to prepare the catalyst by loading the active components, the reaction of direct conversion of olefins and syngas to alcohol has the best reaction activity and target product selectivity.

[0052] As can be seen from the above results, a catalyst and a method for directly converting olefins and syngas into alcohols provided by the present invention have the following main advantages: 1) Compared with the existing industrial hydroformylation reaction technology, due to the use of a novel heterogeneous catalyst, the separation cost of the catalyst from the reactants and products is reduced, making it suitable for actual industrial production; 2) The tandem reaction of olefin hydroformylation-hydrogenation can avoid the separation and purification steps of intermediate products and effectively reduce the generation of by-products; 3) At the same time, the reaction process flow can be shortened, effectively reducing the reaction energy consumption, thereby realizing the efficient and economic synthesis of alcohol products. Using the method of the present invention, olefins and syngas can be directly converted into product alcohols in one step under the action of a heterogeneous catalyst. This method has high economic value and broad application prospects.

[0053] The present invention has been described in detail above, but the present invention is not limited to the specific embodiments described herein. Those skilled in the art understand that other changes and modifications can be made without departing from the scope of the present invention. The scope of the present invention is defined by the appended claims.

Claims

1. A method for directly converting olefins and syngas into alcohols, characterized in that, At room temperature, 1 g of tris(4-vinylphenyl) phosphite, 1 g of tris(4-vinylphenyl)phosphine and 0.05 g of azobisisobutyronitrile were dissolved in 20 ml of tetrahydrofuran solvent. After stirring for 1 h, the above mixed solution was polymerized at 120 °C for 24 h. After polymerization, the solvent was removed under reduced pressure to obtain a porous organic polymer containing a phosphine ligand; At room temperature, 0.24 g of Cu(OAc)2 and 2 g of the polymer prepared above were added to 50 ml of ethanol solvent. After stirring for 24 h, the solvent was removed under reduced pressure to obtain solid powder a; At room temperature, 50.13 mg of Rh(acac)(CO)2 and 2 g of solid powder a were added to 50 ml of ethanol solvent. After stirring for 24 h, the solvent was removed under reduced pressure to obtain catalyst a; 1 g of catalyst a was loaded into the middle of a tubular reactor, quartz sand was filled at both ends, and the mixed feed gas C2H4:CO:H2 = 1:1:8 was introduced. The mixed feed gas was directly fed in the form of gas, and the reaction was carried out at 393 K, 1 MPa, and a mixed feed gas space velocity of 8000 h -1 under the conditions.

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