A bidentate phosphine ligand, preparation method thereof and use thereof in catalyzing enol hydroformylation-hydrogenation reaction to prepare linear alcohol

Abstract

The present invention provides a bidentate phosphine ligand for preparing linear alcohol by hydroformylation-hydrogenation of enolate, and the structure thereof is shown in formula (1). The phosphine ligand has a strong chelating ability with metals, so that the metal active components in the catalyst are not easily lost, the catalyst has a long service life, good recyclability, high catalytic activity, high enolate conversion rate, and good linear selectivity.

Description

Technical Field

[0001] The invention relates to the field of catalysts, and in particular to a bidentate phosphine ligand, a preparation method thereof and use thereof in catalyzing enol hydroformylation-hydrogenation reaction to prepare linear alcohols. Background Art

[0002] Hydroformylation is a synthetic method for preparing aldehydes / alcohols with one more carbon atom using olefins or enols with a C=C double bond functional group as raw materials, and has broad application prospects in industrial production.

[0003] 1,4-Butanediol and 1,5-pentanediol are important organic chemical and fine chemical raw materials, and are the basic raw materials for the production of polyesters and plasticizers. The synthesis of linear hydroxyaldehydes by hydroformylation of enols and subsequent hydrogenation to prepare diols is a green synthesis method with high atom utilization and has good research prospects. At present, the commonly used catalyst is rhodium complex, and the ligand is usually a tertiary phosphine ligand such as triphenylphosphine, but the selectivity of the reaction is low, which increases the production cost.

[0004] Patent CN102428062A discloses a method for preparing 4-hydroxybutyraldehyde by catalyzing the hydroformylation of allyl alcohol using a combination of a rhodium complex and a diphosphine ligand, but the method has a low yield and poor economic efficiency. Patent US6127584 discloses a trialkylphosphine ligand having at least two methyl groups, which increases the ratio of linear products (e.g., 1,4-butanediol) to branched products (e.g., 2-methyl-1,3-propanediol), but the selectivity of the method is still low.

[0005] Therefore, there is an urgent need to develop a ligand that can be used for the enol hydroformylation-hydrogenation reaction to obtain linear alcohols with high selectivity. Summary of the invention

[0006] In view of the above problems existing in the prior art, one of the objects of the present invention is to provide a bidentate phosphine ligand for catalyzing the hydroformylation-hydrogenation reaction of enolate to prepare linear aldehydes, wherein the phosphine ligand has a strong chelating ability with metals, so that the metal active components in the catalyst are not easily lost, the catalyst has a long service life, good recyclability, high catalytic activity, high enolate conversion rate, and good linear selectivity.

[0007] The bidentate phosphine ligand provided by the present invention has a structure as shown in Formula 1:

[0008]

[0009] Another object of the present invention is to provide a method for preparing the bidentate phosphine ligand.

[0010] The method for preparing the bidentate phosphine ligand provided by the present invention comprises the following steps:

[0011] Step 1:

[0012] Dissolve (2-(difluoromethyl)phenyl)phosphoric acid in solvent 1, introduce carbon monoxide gas under the action of a catalyst, and stir to react to generate intermediate M1;

[0013]

[0014] Step 2:

[0015] Dissolve intermediate M1, chloroiodomethane, hexylsilane, tri(pentafluorophenyl)borane and methyl lithium in solvent 2, and stir to react to generate intermediate M2;

[0016]

[0017] Step 3:

[0018] 1) Dissolve carbazole, organic lithium reagent and tetramethylethylenediamine in solvent 3, stir and react to generate an intermediate with the following structure:

[0019]

[0020] 2) Adding the intermediate M2 to the above reaction solution, stirring and reacting to generate the bidentate phosphine ligand.

[0021] According to the method for preparing the bidentate phosphine ligand of the present invention, in step 1,

[0022] The catalyst is metal palladium / calcium carbonate and cuprous iodide; the amount of metal palladium / calcium carbonate added is 0.005-0.01 times the molar amount of (2-(difluoromethyl)phenyl)boric acid (calculated as palladium molar amount), preferably 0.005-0.007 times; the amount of cuprous iodide added is 0.015-0.03 times the molar amount of (2-(difluoromethyl)phenyl)boric acid, preferably 0.015-0.02 times;

[0023] The solvent 1 is selected from acetone and / or dimethyl sulfoxide, preferably dimethyl sulfoxide;

[0024] The reaction temperature is 50-70°C, preferably 50-60°C, and the reaction time is 6.0-12.0h, preferably 10.0-12h.

[0025] According to the method for preparing the bidentate phosphine ligand of the present invention, in step 2,

[0026] The amount of chloroiodomethane added is 1.5-2.0 times the molar amount of the intermediate M1, preferably 1.7-2.0 times; the amount of methyl lithium added is 1.3-1.8 times the molar amount of the intermediate M1, preferably 1.4-1.6 times; the amount of tri(pentafluorophenyl)borane added is 0.1-0.3 times the molar amount of the intermediate M1, preferably 0.1-0.2 times; the amount of hexylsilane added is 1.0-2.0 times the molar amount of the intermediate M1, preferably 1.0-1.3 times;

[0027] The solvent 2 is selected from tetrahydrofuran and diethyl ether, preferably tetrahydrofuran;

[0028] The reaction temperature is -10-0°C, preferably -10 to -5°C, and the reaction time is 1.0-5.0h, preferably 2.0-3.0h.

[0029] According to the method for preparing the bidentate phosphine ligand of the present invention, in step 3,

[0030] The organic lithium reagent is sec-butyl lithium or tert-butyl lithium; the solvent 3 is selected from methyl tert-butyl ether and diethyl ether, preferably methyl tert-butyl ether;

[0031] The amount of tetramethylethylenediamine added is 2.0-4.0 times the molar amount of carbazole, preferably 2.0-3.0 times; the amount of the organic lithium reagent added is 2.0-3.0 times the molar amount of carbazole, preferably 2.0-2.5 times; in sub-step 1) of step 3, the reaction temperature is 0-10°C, preferably 5-10°C, and the reaction time is 5.0-9.0h, preferably 7.0-8.0h;

[0032] The amount of intermediate M2 added is 2.0-3.0 times the molar amount of carbazole, preferably 2.0-2.5 times; in sub-step 2) of step 3, the reaction temperature is 10-30°C, preferably 15-30°C, more preferably room temperature, and the reaction time is 4.0-6.0 hours, preferably 4.5-5.0 hours. Unless otherwise specified, the room temperature described in the present invention is 25°C±5°C.

[0033] Another object of the present invention is to provide the use of the phosphine ligand in preparing linear alcohols by enol hydroformylation-hydrogenation.

[0034] Another object of the present invention is to provide a method for preparing linear alcohols by hydroformylation-hydrogenation of enolates.

[0035] The method for preparing linear alcohols by hydroformylation-hydrogenation of enolate provided by the present invention comprises the following steps:

[0036] A transition metal-containing catalyst and a bidentate phosphine ligand are dissolved in a solvent, and then enolate is added and synthesis gas is introduced to carry out a hydroformylation reaction, and then hydrogen is introduced to react to obtain a linear alcohol.

[0037] According to the preparation method of linear alcohol by hydroformylation-hydrogenation of enolate of the present invention, the transition metal-containing catalyst can be one or more salts of transition metal central atoms such as Fe, Mn, Pt, Pd, Rh, Ru, Ir, Co, etc., preferably one or more salts of Co and Rh. Preferably, the transition metal-containing catalyst is selected from one or more of rhodium acetate, rhodium octanoate, rhodium acetylacetonate, rhodium acetylacetonate carbonyl rhodium, rhodium dicarbonyl acetylacetonate, rhodium triphenylphosphine acetylacetonate, cobalt acetate, cobalt octanoate, cobalt acetylacetonate, triphenylphosphine cobalt acetylacetonate, preferably one or more of rhodium acetylacetonate carbonyl rhodium, triphenylphosphine cobalt acetylacetonate, rhodium octanoate, and cobalt acetate.

[0038] According to the method for preparing linear alcohols by hydroformylation-hydrogenation of enols, the enols are allyl alcohol, 3-butene-1-ol, or 4-pentene-1-ol.

[0039] According to the method for preparing linear alcohol by hydroformylation-hydrogenation of enolate of the present invention, wherein:

[0040] The synthesis gas is CO / H 2 A mixture of CO / H 2 The molar ratio is 1:1 to 1:2, for example, 1:1, 1:1.5, or 1:2;

[0041] The molar ratio of the ene alcohol to the transition metal-containing catalyst is 1:0.001-0.03, preferably 1:0.005-0.02;

[0042] The molar ratio of the transition metal-containing catalyst to the bidentate phosphine ligand is 1:30-100, preferably 1:50-80;

[0043] The solvent is selected from one or more of chlorobenzene, benzene and toluene, preferably benzene and / or toluene;

[0044] The amount of the solvent added is 100-500 times, preferably 100-200 times, more preferably 120-160 times the molar amount of the transition metal-containing catalyst;

[0045] The reaction pressure of the hydroformylation reaction is 1.0-10.0 MPaG, preferably 1.0-6.0 MPaG, more preferably 1.0-3.0 MPaG; the reaction temperature is 60-150°C, preferably 60-100°C, more preferably 60-80°C, and the reaction time is 0.5-5.0h, preferably 0.5-3h, more preferably 0.5-1.0h;

[0046] The reaction pressure of the hydrogenation reaction is 1.0-4.0 MPaG, preferably 3.0-4.0 MPaG; the reaction temperature is 60-120°C, preferably 60-100°C, more preferably 60-80°C; the reaction time is 0.5-5.0h, preferably 0.5-3h, more preferably 0.5-1.0h.

[0047] Without being limited by any theory, the bidentate phosphine ligand of the present invention has a catalytic reaction in which multiple F atoms in the ligand unit can capture hydrogen in the alcoholic hydroxyl group of the enolate to produce hydrogen bonds, thereby coordinating the terminal double bond with the metal atom, and the large steric hindrance of the bidentate phosphine ligand connected to the carbazole causes the carbonyl group to migrate and can only be inserted into the terminal group to obtain a linear aldehyde, and then H is added to the aldehyde to generate an alcohol.

[0048] Beneficial Effects

[0049] The bidentate phosphine ligand of the present invention has a strong chelating ability with metals, so that the metal active components in the catalyst are not easy to be lost, the catalyst has a long service life, good recyclability, high catalytic activity, high ene alcohol conversion rate, and good linear selectivity. Moreover, in the present invention, the catalyst containing transition metals and the hydroformylation-hydrogenation catalyst of the bidentate phosphine ligand are used to obtain linear alcohol in a one-step method, which greatly reduces equipment investment, the ene alcohol conversion rate can reach more than 99.5%, and the linear alcohol selectivity can reach more than 95.5%, which is suitable for industrial large-scale production. DETAILED DESCRIPTION

[0050] The technical solution of the present invention is further described in detail below in conjunction with specific embodiments.

[0051] The sources of the reagent raw materials used in the embodiments of the present invention and the comparative examples are as follows:

[0052] (2-(Difluoromethyl)phenyl)phosphoric acid was purchased from Abovchem;

[0053] 3-Butene-1-ol, carbazole, tetramethylethylenediamine, chloroiodomethane, methyllithium, tris(pentafluorophenyl)borane, hexylsilane, and sec-butyllithium were purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0054] Allyl alcohol was purchased from Alfa Aesar (China) Chemical Co., Ltd.;

[0055] Triphenylphosphine was purchased from Beijing Bailingwei Technology Co., Ltd.;

[0056] Iodide was purchased from Sigma-Aldrich;

[0057] Palladium calcium carbonate was purchased from MacLean Company;

[0058] 4-Penten-1-ol was purchased from Eco Reagents;

[0059] Unless otherwise specified, other reagents and raw materials are common commercially available products.

[0060] The testing methods used in the embodiments of the present invention and the comparative examples are as follows:

[0061] The product structure was determined by nuclear magnetic resonance, and the spectrometer was Bruker AVANCE II 500 MHz;

[0062] Chromatographic analysis was performed using an Agilent 7890B gas chromatograph with an Agilent DB-5 column, injection temperature at 220°C, detector temperature at 50°C, and H 2 Flow rate: 40 / min; air flow rate: 360ml / min. Column box heating program: initial temperature 20℃, heating rate 20℃ / min, hold for 4min; 100-250℃, heating rate 15℃ / min, hold for 10min.

[0063] The present invention will be further described below in conjunction with specific examples. It should be understood that the following examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0064] Example 1

[0065] Example 1-1 Preparation of bidentate phosphine ligand

[0066] Step 1 Preparation of intermediate M1:

[0067] (2-(Difluoromethyl)phenyl)phosphoric acid (1719.4 g, 10 mol), 5% wt palladium calcium carbonate (106.42 g, 0.05 mol), and CuI (28.57 g, 0.15 mol) were dissolved in 2 L acetone, carbon monoxide was introduced, the temperature was raised to 50°C, the reaction was carried out for 10.0 h, the reaction was quenched with 200 ml of 5% wt ammonia water, and then extracted with dichloromethane. The organic phase was concentrated to obtain intermediate M1 (1486.17 g, 4.5 mol).

[0068] Structural characterization of intermediate M1:

[0069] 1 H NMR (500MHz, Chloroform-d): δ7.91(ddd,2H),7.44–7.28(m,6H),7.19(tt,1H),6.01-5.98(t,2H),3.30–3.06(m,4H).

[0070] Step 2 Preparation of intermediate M2:

[0071] Intermediate M1 (3302.6 g, 10 mol), chloroiodomethane (2998.5 g, 17 mol), methyl lithium (307.7 g, 14 mol), tri(pentafluorophenyl)borane (511.98 g, 1 mol), and hexylsilane (1162.8 g, 10 mol) were dissolved in 4 L of tetrahydrofuran, reacted at -10 °C for 2.0 h, and then the reaction solution was concentrated to obtain intermediate M2 (3417.36 g, 9.8 mol).

[0072] Structural characterization of intermediate M2:

[0073] 1 H NMR(500MHz,Chloroform-d)δ7.56(dt,2H),7.34–7.20(m,6H),6.09-5.82(t,2H),3.14(tdd,4H).

[0074] Step 3 Preparation of bidentate phosphine ligand:

[0075] Dissolve carbazole (1672.1 g, 10 mol) and tetramethylethylenediamine (2324.1 g, 20 mol) in 3 L of ether, add tert-butyl lithium (1281.0 g, 20 mol), react at 5 °C for 7.0 h, then add intermediate M2 (6974.2 g, 20 mol), react at room temperature for 4.5 h, concentrate the reaction solution, and recrystallize with methanol to obtain a bidentate phosphine ligand (7377.8 g, 9.0 mol).

[0076] Structural characterization of bidentate phosphine ligands:

[0077] 1 H NMR(500MHz,Chloroform-d)δ7.99(dd,2H),7.90(s,1H),7.40–7.33(m,4H),7.32 –7.19(m,14H),7.05(dd,2H),6.10-5.80(t,4H),4.16(d,2H),3.15-3.05(dd,8H).

[0078] Example 1-2 Preparation of 1,4-butanediol by hydroformylation-hydrogenation of allyl alcohol

[0079] Allyl alcohol, triphenylphosphine cobalt acetylacetonate, the bidentate phosphine ligand prepared in Example 1-1, and benzene were mixed uniformly in a molar ratio of 1:0.005:0.25:0.8, added to a reactor, and synthesis gas (CO / H 2The molar ratio is 1:1) the system pressure is controlled to 1.0 MPaG, the reaction is carried out at a temperature of 60°C for 0.5 h, and then hydrogen is introduced to control the system pressure to 3.0 MPaG, and the reaction is carried out at 80°C for 0.5 h. 1,4-butanediol is obtained by gas chromatography analysis, the allyl alcohol conversion rate is 99.5%, and the 1,4-butanediol selectivity is 97.8%.

[0080] Structural characterization of the product 1,4-butanediol:

[0081] 1 H NMR(500MHz,Chloroform-d)δ3.64-3.57(m,4H),2.74-2.68(m,2H),1.64–1.54(m,4H).

[0082] Example 2

[0083] Example 2-1 Preparation of bidentate phosphine ligand

[0084] Step 1 Preparation of intermediate M1:

[0085] (2-(Difluoromethyl)phenyl)phosphoric acid (1719.4 g, 10 mol), 5%wt palladium calcium carbonate (149.0 g, 0.07 mol), and CuI (38.09 g, 0.2 mol) were dissolved in 2L dimethyl sulfoxide, carbon monoxide was introduced, the temperature was raised to 60°C, the reaction was carried out for 12.0 h, the reaction was quenched with 200 ml of 5%wt ammonia water, and then extracted with dichloromethane. The organic phase was concentrated to obtain intermediate M1 (1519.2 g, 4.6 mol). 1 The H NMR characterization data were consistent with those of Example 1-1.

[0086] Step 2 Preparation of intermediate M2:

[0087] Intermediate M1 (3302.6 g, 10 mol), chloroiodomethane (3527.6 g, 20 mol), methyl lithium (351.66 g, 16 mol), tris(pentafluorophenyl)borane (1024.0 g, 2 mol), hexylsilane (1511.6 g, 13 mol) were dissolved in 4 L of ether and reacted at -5 °C for 3.0 h. The reaction solution was then concentrated to obtain intermediate M2 (3452.2 g, 9.9 mol). 1 The H NMR characterization data were consistent with those of Example 1-1.

[0088] Step 3 Preparation of bidentate phosphine ligand:

[0089] Carbazole (1672.1 g, 10 mol) and tetramethylethylenediamine (3486.1 g, 30 mol) were dissolved in 4 L of methyl tert-butyl ether, sec-butyl lithium (1601.2 g, 25 mol) was added, and the mixture was reacted at 10 °C for 8.0 h. Then, intermediate M2 (8711.75 g, 25 mol) was added, and the mixture was reacted at room temperature for 5.0 h. The reaction solution was concentrated and recrystallized from methanol to obtain a bidentate phosphine ligand (7541.8 g, 9.2 mol). 1 The H NMR characterization data were consistent with those of Example 1-1.

[0090] Example 2-23-Butene-1-ol hydroformylation-hydrogenation to prepare 1,5-pentanediol

[0091] 3-Butene-1-ol, acetylacetonato carbonyl rhodium (Rh(acac)(CO) 2 ), the bidentate phosphine ligand prepared in the above Example 2-1 and toluene were mixed uniformly in a molar ratio of 1:0.02:1.6:2.4, added to the reactor, and the synthesis gas (CO / H 2 The molar ratio is 1:1) the system pressure is controlled at 3.0 MPaG, the reaction is carried out at 80°C for 1.0 h, and then hydrogen is introduced to control the system pressure to 4.0 MPaG, the reaction is carried out at 60°C for 1.0 h, and 1,5-pentanediol is obtained by gas chromatography analysis. The conversion rate of 3-butene-1-ol is 99.5%, and the selectivity of 1,5-pentanediol is 95.8%.

[0092] Structural characterization of the product 1,5-pentanediol:

[0093] 1 H NMR(500MHz,Chloroform-d)δ3.56(q,4H),2.64(t,2H),1.61–1.52(m,4H),1.47–1.37(m,2H).

[0094] Example 3

[0095] Example 3-1 Preparation of bidentate phosphine ligand

[0096] Step 1 Preparation of intermediate M1:

[0097] (2-(Difluoromethyl)phenyl)phosphoric acid (1719.4 g, 10 mol), 5%wt palladium calcium carbonate (127.7 g, 0.06 mol), and CuI (34.3 g, 0.18 mol) were dissolved in 2L dimethyl sulfoxide, carbon monoxide was introduced, the temperature was raised to 55°C, the reaction was continued for 11.0 h, the reaction was quenched with 200 ml of 5%wt ammonia water, and then extracted with dichloromethane. The organic phase was concentrated to obtain intermediate M1 (1519.2 g, 4.6 mol). 1The H NMR characterization data were consistent with those of Example 1-1.

[0098] Step 2 Preparation of intermediate M2:

[0099] Intermediate M1 (3302.6 g, 10 mol), chloroiodomethane (3174.8 g, 18 mol), methyl lithium (329.68 g, 15 mol), tris(pentafluorophenyl)borane (768.0, 1.5 mol), hexylsilane (1395.3 g, 12 mol) were dissolved in 4 L of tetrahydrofuran and reacted at -8 °C for 2.5 h. The reaction solution was then concentrated to obtain intermediate M2 (3382.5 g, 9.7 mol). 1 The H NMR characterization data were consistent with those of Example 1-1.

[0100] Step 3 Preparation of bidentate phosphine ligand:

[0101] Carbazole (1672.1 g, 10 mol) and tetramethylethylenediamine (2905.1 g, 25 mol) were dissolved in 4 L of methyl tert-butyl ether, sec-butyl lithium (1473.1 g, 23 mol) was added, and the mixture was reacted at 8 °C for 7.5 h. Then, intermediate M2 (8014.8 g, 23 mol) was added, and the mixture was reacted at room temperature for 5.0 h. The reaction solution was concentrated and recrystallized from methanol to obtain a bidentate phosphine ligand (7459.8 g, 9.1 mol). 1 The H NMR characterization data were consistent with those of Example 1-1.

[0102] Example 3-23-Butene-1-ol hydroformylation-hydrogenation to prepare 1,5-pentanediol

[0103] 3-Butene-1-ol, Rh(acac)(CO) 2 The bidentate phosphine ligand prepared in Example 3-1 and toluene were mixed uniformly in a molar ratio of 1:0.02:1.6:2.4, added to the reactor, and the synthesis gas (CO / H 2 The molar ratio is 1:1) the system pressure is controlled at 3.0 MPaG, the reaction is carried out at a temperature of 80°C for 1.0 h, and then hydrogen is introduced, the system pressure is controlled at 3.5 MPaG, and the reaction is carried out at 75°C for 1.0 h. According to gas chromatography analysis, 1,5-pentanediol is obtained, the conversion rate of 3-butene-1-ol is 99.6%, and the selectivity of 1,5-pentanediol is 96.8%. The product 1,5-pentanediol 1 The H NMR characterization data were consistent with those of Example 2-2.

[0104] Example 4

[0105] Example 4-1 Preparation of bidentate phosphine ligand

[0106] Step 1 Preparation of intermediate M1:

[0107] (2-(Difluoromethyl)phenyl)phosphoric acid (1719.4 g, 10 mol), 5%wt palladium calcium carbonate (127.7 g, 0.06 mol), and CuI (34.3 g, 0.18 mol) were dissolved in 2L dimethyl sulfoxide, carbon monoxide was introduced, the temperature was raised to 55°C, the reaction was continued for 11.0 h, the reaction was quenched with 200 ml of 5%wt ammonia water, and then extracted with dichloromethane. The organic phase was concentrated to obtain intermediate M1 (1519.2 g, 4.6 mol). 1 The H NMR characterization data were consistent with those of Example 1-1.

[0108] Step 2 Preparation of intermediate M2:

[0109] Intermediate M1 (3302.6 g, 10 mol), chloroiodomethane (3174.8 g, 18 mol), methyl lithium (329.68 g, 15 mol), tris(pentafluorophenyl)borane (768.0, 1.5 mol), hexylsilane (1395.3 g, 12 mol) were dissolved in 4 L of tetrahydrofuran and reacted at -8 °C for 2.5 h. The reaction solution was then concentrated to obtain intermediate M2 (3382.5 g, 9.7 mol). 1 The H NMR characterization data were consistent with those of Example 1-1.

[0110] Step 3 Preparation of bidentate phosphine ligand:

[0111] Carbazole (1672.1 g, 10 mol) and tetramethylethylenediamine (2905.1 g, 25 mol) were dissolved in 4 L of methyl tert-butyl ether, sec-butyl lithium (1473.1 g, 23 mol) was added, and the mixture was reacted at 8 °C for 7.5 h. Then, intermediate M2 (8014.8 g, 23 mol) was added, and the mixture was reacted at room temperature for 5.0 h. The reaction solution was concentrated and recrystallized from methanol to obtain a bidentate phosphine ligand (7459.8 g, 9.1 mol). 1 The H NMR characterization data were consistent with those of Example 1-1.

[0112] Example 4-24-Hydroformylation of pentenol to prepare 1,6-hexanediol

[0113] 4-Pentenol, cobalt acetate, the bidentate phosphine ligand prepared in Example 4-1, and toluene were mixed uniformly in a molar ratio of 1:0.02:1.6:2.4, added to a reactor, and synthesis gas (CO / H 2 The molar ratio is 1:2) the system pressure is controlled at 3.0 MPaG, the reaction is carried out at 80°C for 1.0 h, and then hydrogen is introduced to control the system pressure to 4.0 MPaG, the reaction is carried out at 60°C for 0.5 h, and 1,6-hexanediol is obtained by gas chromatography analysis, the conversion rate of 4-pentenol is 99.8%, and the selectivity of 1,6-hexanediol is 97.2%.

[0114] Structural characterization of the product 1,6-hexanediol:

[0115] 1 H NMR(500MHz,Chloroform-d)δ3.56(q,4H),2.65(t,2H),1.60–1.51(m,4H),1.47–1.37(m,4H).

[0116] Comparative Example 1

[0117] 3-Butene-1-ol hydroformylation-hydrogenation to prepare 1,5-pentanediol:

[0118] Refer to Example 3-2, the only difference is that the bidentate phosphine ligand is replaced by an equimolar amount of triphenylphosphine, and other raw materials and operating conditions remain unchanged.

[0119] After the reaction, 1,5-pentanediol was obtained by gas chromatography analysis; the conversion rate of 3-butene-1-ol was 95.2%, and the selectivity of 1,5-pentanediol was 75.2%.

[0120] Comparative Example 2

[0121] Allyl alcohol hydroformylation-hydrogenation to prepare 1,4-butanediol:

[0122] Referring to Example 1-2, the only difference is that the bidentate phosphine ligand is replaced by an equimolar amount of triphenyl phosphate, and other raw materials and operating conditions remain unchanged.

[0123] After the reaction, 1,4-butanediol was obtained by gas chromatography analysis; the allyl alcohol conversion rate was 97.2%, and the 1,4-butanediol selectivity was 78.2%.

[0124] Experimental Example Catalyst Performance Investigation

[0125] 1. Reaction solution extraction

[0126] 1,4-Butanediol in the reaction solution of Example 1-2 was distilled off at 1.33 KPa and 88° C. to obtain a remaining reaction solution.

[0127] 2. Preparation of 1,4-butanediol by hydroformylation-hydrogenation of reaction liquid

[0128] Add an equal amount of allyl alcohol as in Example 1-2 to the remaining reaction solution and mix well, then add it to the reactor and introduce synthesis gas (CO / H 2 The molar ratio is 1:1) the system pressure is controlled to 1.0 MPaG, the reaction is carried out at a temperature of 60°C for 0.5 h, and then hydrogen is introduced to control the system pressure to 3.0 MPaG, and the reaction is carried out at 80°C for 0.5 h. The conversion rate and selectivity of allyl alcohol are analyzed by gas chromatography, as shown in Table 1 below:

[0129] Table 1 Cyclic performance of catalysts

[0130] Cycle times (times) Allyl alcohol conversion rate (%) 1,4-Butanediol selectivity (%) 1 99.4 97.8 5 99.2 97.8 10 98.8 97.5 15 98.5 97.4 20 98.4 97.0 25 98.0 96.5 30 97.6 96.1

[0131] As can be seen from Table 1, the bidentate phosphine ligand of the present invention has a strong chelating ability with metals, so that the metal active components in the catalyst are not easy to be lost, the catalyst has a long service life, and the catalyst can be recycled for 30 times, the ene alcohol conversion rate can still reach 97.6%, and the linear alcohol selectivity can still reach 96.1%. Therefore, it has very good recyclability.

Claims

1. A bidentate phosphine ligand, the structure of which is shown in Formula 1:

2. A method for preparing a bidentate phosphine ligand as claimed in claim 1, characterized in that: The following steps are involved: Step 1: Dissolve (2-(difluoromethyl)phenyl)phosphoric acid in solvent 1, introduce carbon monoxide gas under the action of a catalyst, and stir to react to generate intermediate M1; Step 2: Dissolve intermediate M1, chloroiodomethane, hexylsilane, tri(pentafluorophenyl)borane and methyl lithium in solvent 2, and stir to react to generate intermediate M2; Step 3: 1) Dissolve carbazole, organic lithium reagent and tetramethylethylenediamine in solvent 3, stir and react to generate an intermediate with the following structure: 2) adding the intermediate M2 to the above reaction solution, stirring and reacting to generate the bidentate phosphine ligand; in, In step 1, the catalyst is metal palladium / calcium carbonate and cuprous iodide; the solvent 1 is selected from acetone and / or dimethyl sulfoxide; In step 2, the solvent 2 is selected from tetrahydrofuran and / or diethyl ether; In step 3, the solvent 3 is selected from methyl tert-butyl ether and / or diethyl ether.

3. The preparation method according to claim 2, wherein In step 1, The amount of metal palladium / calcium carbonate added is 0.005-0.01 times the molar amount of (2-(difluoromethyl)phenyl)phosphoric acid calculated as the molar amount of palladium; the amount of cuprous iodide added is 0.015-0.03 times the molar amount of (2-(difluoromethyl)phenyl)phosphoric acid; The solvent 1 is dimethyl sulfoxide; The reaction temperature is 50-70°C, and the reaction time is 6.0-12.0h.

4. The preparation method according to claim 2, wherein In step 2, The amount of chloroiodomethane added is 1.5-2.0 times the molar amount of the intermediate M1; the amount of methyl lithium added is 1.3-1.8 times the molar amount of the intermediate M1; the amount of tri(pentafluorophenyl)borane added is 0.1-0.3 times the molar amount of the intermediate M1; the amount of hexylsilane added is 1.0-2.0 times the molar amount of the intermediate M1; The solvent 2 is tetrahydrofuran; The reaction temperature is -10-0°C, and the reaction time is 1.0-5.0h.

5. The preparation method according to claim 2, wherein: In step 3, The organic lithium reagent is sec-butyl lithium or tert-butyl lithium; the solvent 3 is methyl tert-butyl ether; The amount of tetramethylethylenediamine added is 2.0-4.0 times the molar amount of carbazole; the amount of the organic lithium reagent added is 2.0-3.0 times the molar amount of carbazole; in sub-step 1) of step 3, the reaction temperature is 0-10°C and the reaction time is 5.0-9.0h; The amount of the intermediate M2 added is 2.0-3.0 times the molar amount of carbazole; in sub-step 2) of step 3, the reaction temperature is 10-30° C., and the reaction time is 4.0-6.0 hours.

6. The preparation method according to claim 3, wherein: In step 1, The amount of metal palladium / calcium carbonate added is 0.005-0.007 times the molar amount of (2-(difluoromethyl)phenyl)phosphoric acid calculated as the molar amount of palladium; the amount of cuprous iodide added is 0.015-0.02 times the molar amount of (2-(difluoromethyl)phenyl)phosphoric acid; The reaction temperature is 50-60°C and the reaction time is 10.0-12h.

7. The preparation method according to claim 4, wherein In step 2, The amount of chloroiodomethane added is 1.7-2.0 times the molar amount of the intermediate M1; the amount of methyl lithium added is 1.4-1.6 times the molar amount of the intermediate M1; the amount of tri(pentafluorophenyl)borane added is 0.1-0.2 times the molar amount of the intermediate M1; the amount of hexylsilane added is 1.0-1.3 times the molar amount of the intermediate M1; The reaction temperature is -10 to -5°C, and the reaction time is 2.0-3.0h.

8. The preparation method according to claim 5, wherein In step 3, The amount of tetramethylethylenediamine added is 2.0-3.0 times the molar amount of carbazole; the amount of the organic lithium reagent added is 2.0-2.5 times the molar amount of carbazole; in sub-step 1) of step 3, the reaction temperature is 5-10° C. and the reaction time is 7.0-8.0 h; The amount of the intermediate M2 added is 2.0-2.5 times the molar amount of carbazole; in sub-step 2) of step 3, the reaction temperature is 15-30° C., and the reaction time is 4.5-5.0 hours.

9. Use of the bidentate phosphine ligand as claimed in claim 1 in the preparation of linear alcohols by hydroformylation-hydrogenation of enols, wherein the enols are allyl alcohol, 3-butene-1-ol or 4-pentene-1-ol.

10. A method for preparing linear alcohols by enol hydroformylation-hydrogenation, comprising the following steps: The catalyst containing transition metal and bidentate phosphine ligand are dissolved in a solvent, and then enolate is added, and synthesis gas is introduced to carry out hydroformylation reaction, and then hydrogen is introduced to react to obtain linear alcohol. The bidentate phosphine ligand is the bidentate phosphine ligand according to claim 1, or the bidentate phosphine ligand obtained according to the preparation method according to any one of claims 2 to 5; The transition metal-containing catalyst is selected from one or more of rhodium acetate, rhodium octanoate, rhodium acetylacetonate, carbonyl rhodium acetylacetonate, rhodium dicarbonyl acetylacetonate, rhodium triphenylphosphine acetylacetonate, cobalt acetate, cobalt octanoate, cobalt acetylacetonate, and cobalt triphenylphosphine acetylacetonate; The enol is allyl alcohol, 3-butene-1-ol or 4-pentene-1-ol; The synthesis gas is a mixture of CO / H2.

11. The method according to claim 10, wherein: The transition metal-containing catalyst is one or more of acetylacetonato carbonyl rhodium, triphenylphosphine cobalt acetylacetonate, rhodium octanoate, and cobalt acetate.

12. The method according to claim 10, wherein: CO / H2 molar ratio of 1:1 to 1:2; The molar ratio of the enolate to the transition metal-containing catalyst is 1:0.001-0.03; The molar ratio of the transition metal-containing catalyst to the bidentate phosphine ligand is 1:30-100; The solvent is selected from one or more of chlorobenzene, benzene and toluene; The amount of the solvent added is 100-500 times the molar amount of the transition metal-containing catalyst; The reaction pressure of the hydroformylation reaction is 1.0-10.0 MPaG; the reaction temperature is 60-150° C., and the reaction time is 0.5-5.0 h; The reaction pressure of the hydrogenation reaction is 1.0-4.0 MPaG; the reaction temperature is 60-120° C.; and the reaction time is 0.5-5.0 h.

13. The method according to claim 12, wherein: The molar ratio of the enolate to the transition metal-containing catalyst is 1:0.005-0.02; The molar ratio of the transition metal-containing catalyst to the bidentate phosphine ligand is 1:50-80; The solvent is benzene and / or toluene; The amount of the solvent added is 100-200 times the molar amount of the transition metal-containing catalyst; The reaction pressure of the hydroformylation reaction is 1.0-6.0 MPaG, the reaction temperature is 60-100° C., and the reaction time is 0.5-3 h; The reaction pressure of the hydrogenation reaction is 3.0-4.0 MPaG, the reaction temperature is 60-100° C., and the reaction time is 0.5-3 h.

14. The method according to claim 13, wherein: The amount of the solvent added is 120-160 times the molar amount of the transition metal-containing catalyst; The reaction pressure of the hydroformylation reaction is 1.0-3.0 MPaG; the reaction temperature is 60-80°C, and the reaction time is 0.5-1.0h; The reaction temperature of the hydrogenation reaction is 60-80° C., and the reaction time is 0.5-1.0 h.

Images