Preparation method of ester-terminated siloxane

Abstract

The invention discloses a preparation method of ester-terminated siloxane, and belongs to the technical field of synthesis of terminated siloxane. Comprising the following steps: by taking a vinyl siloxane compound, carbon monoxide and an alcohol compound as raw materials, under the action of a palladium-based metal catalyst and a phosphine ligand, adding a solvent, and reacting in a reaction gas atmosphere at 40-180 DEG C by a one-step hydrogen esterification method to obtain ester-terminated siloxane, the reaction gas being carbon monoxide. According to the preparation method, ester-terminated siloxane is prepared through a hydrogen esterification reaction, side reactions in a traditional hydrosilylation method are avoided, work such as product separation and purification is simplified, and raw materials are cheaper and easier to obtain; the method for preparing the ester-terminated siloxane is simple and convenient in process and low in raw material cost, and has certain feasibility for realizing industrial production of the ester-terminated siloxane; the method provides a new way with high efficiency and high selectivity for the preparation of ester-terminated siloxane.

Description

Technical Field

[0001] The present invention relates to the technical field of synthesis of end-capped siloxanes, and relates to a method for preparing ester-end-capped siloxanes, and specifically to a method for preparing ester-end-capped siloxanes by hydrogen esterification of vinyl-end-capped siloxanes using palladium as a catalyst. Background Art

[0002] Since silicone materials have a special molecular structure and composition of Si-O-Si inorganic main chain and organic side chain, they have unique excellent properties, such as oxidation resistance, electrical insulation, radiation resistance, weather resistance, flame retardancy, and mildew resistance. They are widely used in fine chemical products, medical treatment, agriculture, coatings, paints and other fields.

[0003] Polysiloxane is the main organosilicon material, which can be generally divided into two categories: one is that most of the side chains or end chains are methyl groups, with a small amount of phenyl or hydrogen. However, due to the lack of functional groups, it has become a bottleneck that hinders its expansion into the high-end market; the other is to introduce organic functional groups into the side chains or end chains to obtain some special properties. This strategy is an important method for siloxane modification. For example, the introduction of ester groups into the polysiloxane molecular chain makes the polysiloxane carbon dioxide-philic, which can be used as an emulsifier for carbon dioxide in the supercritical field, or the carbonyl group in the ester group is used to coordinate with rare earth ions to prepare organosilicon luminescent materials. Therefore, it is of great significance to develop a method for the efficient synthesis of ester-terminated siloxanes.

[0004] The traditional method for preparing ester-terminated siloxanes is to use hydrogen silane (oxygen) alkane and acrylic ester compounds to prepare them by hydrosilylation reaction under cerium (Angew.Chem.Int.Ed.2017,56,628.) or platinum (J.Macromol.Sci.A.2014,51,16.) catalysts. Under the reaction conditions, the ester group is often further reduced, resulting in the production of by-products, which increases the difficulty of product separation and purification. The olefin hydroesterification reaction is an efficient method for preparing ester compounds in one step because of its advantages such as cheap and easy-to-obtain raw materials, no side reactions, and high selectivity. Hydroesterification reactions usually require the addition of acid as an additional additive to promote the reaction, which will cause corrosion of the equipment and will inevitably increase the investment cost for future industrial applications. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing ester-terminated siloxane, wherein the ester-terminated siloxane is prepared efficiently and highly selectively by a one-step dihydroesterification reaction of vinyl-terminated siloxane, which greatly shortens the process flow and reduces production costs, equipment investment and energy consumption.

[0006] In order to achieve the above purpose, the technical solution adopted in this application is:

[0007] The object of the present invention is to provide a method for preparing an ester-terminated siloxane, comprising the following steps:

[0008] Using vinyl siloxane compounds and alcohol compounds as raw materials, under the action of palladium-based metal catalysts and phosphine ligands, adding solvents, and reacting at 40°C to 180°C in a reaction gas atmosphere to obtain ester-terminated siloxane by a one-step hydroesterification method, wherein the reaction gas is carbon monoxide;

[0009] The structural formula of the ester-terminated siloxane is shown in Formula II or Formula II-1:

[0010]

[0011] Among them, R 1 , R 2 and R 3 R is independently selected from hydrogen, C1-C8 alkyl, aryl, C1-C8 alkoxy, aryloxy, silyloxy, silyl, trifluoromethyl or hydroxyl; 4 Selected from alcohol, phenol, polyol, polyphenol, polyol or sugar; n≥1.

[0012] The synthetic route of ester-terminated siloxane is as follows:

[0013]

[0014] Furthermore, the molar ratio of the vinyl siloxane compound to the alcohol compound is 1:1-10.

[0015] Furthermore, the amount of the palladium-based metal catalyst used is 0.1 mol% to 20 mol% of the total reaction system, and the molar ratio of the palladium-based metal catalyst to the phosphine ligand is 1-30:1-10.

[0016] Furthermore, the pressure of the hydroesterification reaction is 1 bar to 40 bar, and the reaction time is 2 h to 72 h.

[0017] Furthermore, an additive is added during the hydroesterification reaction, wherein the amount of the additive is 0 mol% to 20 mol% of the total reaction system, and the additive is selected from reagents that can provide a proton source.

[0018] Furthermore, the palladium-based metal catalyst is zero-valent palladium or divalent palladium-based metal.

[0019] Furthermore, the phosphine ligand is a monodentate or bidentate phosphine ligand.

[0020] Furthermore, the alcohol compound is selected from alcohol, phenol, polyol, polyphenol, polyol or sugar.

[0021] Furthermore, the structural formula of the vinyl siloxane compound is as shown in Formula I:

[0022]

[0023] Among them, R 1 , R 2 and R 3 Each is independently selected from hydrogen, C1-C8 alkyl, aryl, C1-C8 alkoxy, aryloxy, silyloxy, silyl, trifluoromethyl or hydroxyl.

[0024] Furthermore, the solvent is selected from at least one of C1-C6 alkane solvents, C1-C6 alcohol solvents, aromatic hydrocarbon solutions, ether solutions, amide solutions or nitrile solvents.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] The present invention provides a method for generating ester-terminated siloxane by using vinyl siloxane, carbon monoxide and alcohol compounds under the action of metal catalyst / ligand or metal catalyst / ligand / acid, and the ester-terminated siloxane is prepared efficiently and selectively by one-step dihydroesterification reaction of vinyl-terminated siloxane, which greatly shortens the process flow and reduces production cost, equipment investment and energy consumption. The advantages of this method are: the vinyl siloxane compound as a raw material is cheap and easy to obtain, the selectivity and yield of the target product are both high, the conditions are relatively mild, the experimental operation is simple, and no side reactions are generated. The method can be carried out without acid as an additive, which reduces production cost and equipment loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is the gel permeation chromatogram of compound 12 of the present invention. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] It should be noted that the professional terms used in the present invention are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention. Unless otherwise specifically stated, the various raw materials, reagents, instruments and equipment used in the following embodiments of the present invention can be purchased from the market or prepared by existing methods.

[0030] In the prior art, for example, ester-terminated siloxanes are prepared by hydrosilylation reaction of hydrogen silane and acrylic acid ester compounds under cerium or platinum catalysts. Under such reaction conditions, the ester groups are often further reduced, resulting in the production of by-products, which increases the difficulty of product separation and purification. Based on the above problems, the present invention provides a one-step hydroesterification method for synthesizing ester-terminated siloxanes without acid as an additive, comprising the following steps:

[0031] Vinyl siloxane compounds and alcohol compounds are used as raw materials, under the action of palladium-based metal catalysts and phosphine ligands, after adding solvent, a one-step hydroesterification reaction is carried out at 40°C to 180°C in a reaction gas atmosphere to obtain ester-terminated siloxane; wherein the reaction gas is carbon monoxide (CO).

[0032] The structural formula of the ester-terminated siloxane is shown in Formula II or Formula II-1:

[0033]

[0034] Among them, R 1 , R 2 and R 3 R is independently selected from hydrogen, C1-C8 alkyl, aryl, C1-C8 alkoxy, aryloxy, silyloxy, silyl, trifluoromethyl or hydroxyl; 4 Selected from alcohol, phenol, polyol, polyphenol, polyol or sugar; n≥1.

[0035] The synthetic route of ester-terminated siloxane is as follows:

[0036]

[0037] The reaction mechanism is as follows:

[0038]

[0039] The palladium-based metal catalyst generates intermediate 1 under the action of alcohol and phosphine ligands, and intermediate 1 migrates and inserts into alkenyl silicon to form intermediate 2, and then intermediate 2 forms acyl palladium intermediate 3 through CO coordination and insertion, and intermediate 3 obtains the final product ester through alcoholysis. The present invention uses a method for generating ester-terminated siloxanes by using vinyl siloxane, carbon monoxide and alcohol compounds under the action of metal catalyst / ligand or metal catalyst / ligand / acid, and uses a one-step double hydrogen esterification reaction of vinyl-terminated siloxane to efficiently and selectively prepare ester-terminated siloxanes, avoiding the occurrence of side reactions in traditional hydrosilylation methods, simplifying product separation, purification and other work, and making raw materials cheaper and easier to obtain; the method provides a new efficient and highly selective way for the preparation of ester-terminated siloxanes, greatly shortens the process flow, and reduces production costs, equipment investment and energy consumption.

[0040] In some specific embodiments, vinyl-terminated siloxane, alcohol compound, metal catalyst precursor, ligand, carbon monoxide and solvent are necessary materials for the reaction, and the reaction can be completed in the presence of the necessary materials.

[0041] In some specific embodiments, the molar ratio of the vinyl siloxane compound to the alcohol compound is 1:1 to 10. As a preferred embodiment of the present invention, the molar ratio of the vinyl siloxane compound to the alcohol compound is 1:1.5 to 6.

[0042] In some specific embodiments, the amount of the palladium-based metal catalyst is 0.1 mol% to 20 mol% of the total reaction system, and the molar ratio of the palladium-based metal catalyst to the phosphine ligand is 1 to 30: 1 to 10. As a preferred embodiment of the present invention, the amount of the palladium-based metal catalyst is 5 mol% to 10 mol% of the total reaction system; the molar ratio of the palladium-based metal catalyst to the phosphine ligand is 1: 1 to 2.

[0043] In some specific embodiments, the hydroesterification reaction pressure is 1 bar to 40 bar, and the reaction time is 2 hours to 72 hours. As a preferred embodiment of the present invention, the hydroesterification reaction temperature is 50°C to 100°C, the reaction pressure is 15 bar to 30 bar, and the reaction time is 6 hours to 12 hours.

[0044] In some specific embodiments, an additive is added to the hydroesterification reaction, and the amount of the additive is 0 mol% to 20 mol% of the total reaction system. The additive is selected from a reagent that can provide a proton source. The reagent that provides a proton source includes but is not limited to hydrochloric acid, p-toluenesulfonic acid, hydroiodic acid, hydrobromic acid or water.

[0045] In some specific embodiments, the palladium-based metal catalyst is zero-valent palladium or divalent palladium-based metal.

[0046] In some specific embodiments, the phosphine ligand is a monodentate or bidentate phosphine ligand.

[0047] In some specific embodiments, the alcohol compound includes but is not limited to alcohol, phenol, polyol, polyphenol, polyol or sugar.

[0048] In some specific embodiments, the structural formula of the vinyl siloxane compound is as shown in Formula I:

[0049]

[0050] Among them, R 1 , R 2 and R 3Each of them is independently selected from one of the group including but not limited to hydrogen, C1-C8 alkyl, aryl, C1-C8 alkoxy, aryloxy, silyloxy, silicon, trifluoromethyl and hydroxyl.

[0051] Furthermore, the solvent includes but is not limited to at least one of a C1-C6 alkane solvent, a C1-C6 alcohol solvent, an aromatic hydrocarbon solution, an ether solution, an amide solution or a nitrile solvent.

[0052] The invention is further described below through specific examples.

[0053] Example 1

[0054] A method for preparing an ester-terminated siloxane comprises the following steps:

[0055] A bidentate phosphine ligand such as formula III, divalent palladium, p-toluenesulfonic acid, vinyl-terminated siloxane compound a and methanol are added to a reactor in a molar ratio of 0.2:0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as a solvent. After nitrogen protection, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times, and then carbon monoxide is filled until the pressure of the reactor is 20ba. The reaction temperature is controlled to 80°C, and the reaction is carried out for 24 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 1 is obtained by column chromatography separation, with a yield of 54% and a selectivity of 80%.

[0056]

[0057] The H-NMR spectrum characterization of the ester-terminated siloxane compound of formula 1: 1 HNMR (500MHz, CDCl 3 )δ3.67(s,6H),2.32-2.24(m,4H),0.88-0.82(m,4H),0.07(s,12H).

[0058] Example 2

[0059] A method for preparing an ester-terminated siloxane comprises the following steps:

[0060] A bidentate phosphine ligand such as formula V, divalent palladium, p-toluenesulfonic acid, vinyl-terminated siloxane compound a and methanol are added into a reactor in a molar ratio of 0.2:0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor is 20 bar. The reaction temperature is controlled to 80°C, and the reaction is carried out for 24 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 75% and a selectivity of 92%.

[0061]

[0062] Example 3

[0063] A method for preparing an ester-terminated siloxane comprises the following steps:

[0064] A bidentate phosphine ligand such as formula VI, divalent palladium, p-toluenesulfonic acid, vinyl-terminated siloxane compound a and methanol are added into a reactor in a molar ratio of 0.2:0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor is 20 bar. The reaction temperature is controlled to 80°C, and the reaction is carried out for 24 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 1 is obtained by column chromatography separation, with a yield of 41% and a selectivity of 74%.

[0065]

[0066] Example 4

[0067] A method for preparing an ester-terminated siloxane comprises the following steps:

[0068] A bidentate phosphine ligand such as formula VII, divalent palladium, p-toluenesulfonic acid, vinyl-terminated siloxane compound a and methanol are added into a reactor in a molar ratio of 0.2:0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor is 20 bar. The reaction temperature is controlled to 80°C, and the reaction is carried out for 24 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 1 is obtained by column chromatography separation, with a yield of 61% and a selectivity of 83%.

[0069]

[0070] Example 5

[0071] A method for preparing an ester-terminated siloxane comprises the following steps:

[0072] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound a and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor is 20 bar. The reaction temperature is controlled to 80°C, and the reaction is carried out for 24 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 1 is obtained by column chromatography separation, with a yield of 83% and a selectivity of 99%.

[0073] Example 6

[0074] A method for preparing an ester-terminated siloxane comprises the following steps:

[0075] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound a and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor is 20 bar. The reaction temperature is controlled to 80°C, and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 1 is obtained by column chromatography separation, with a yield of 82% and a selectivity of 99%.

[0076] Example 7

[0077] A method for preparing an ester-terminated siloxane comprises the following steps:

[0078] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound a and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor reaches 30 bar. The reaction temperature is controlled to 80°C, and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 1 is obtained by column chromatography separation, with a yield of 94% and a selectivity of 99%.

[0079] Example 8

[0080] A method for preparing an ester-terminated siloxane comprises the following steps:

[0081] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound a and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor reaches 30 bar. The reaction temperature is controlled at 60°C, and the reaction is carried out for 24 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 1 is obtained by column chromatography separation, with a yield of 72% and a selectivity of 92%.

[0082] Example 9

[0083] A method for preparing an ester-terminated siloxane comprises the following steps:

[0084] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound a and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M dichloroethane is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor is 30 bar. The reaction temperature is controlled to 80°C, and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 1 is obtained by column chromatography separation, with a yield of 66% and a selectivity of 99%.

[0085] Example 10

[0086] A method for preparing an ester-terminated siloxane comprises the following steps:

[0087] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound a and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M 1,4-dioxane is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor is 30 bar. The reaction temperature is controlled to 80°C, and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 1 is obtained by column chromatography separation, with a yield of 26% and a selectivity of 99%.

[0088] Embodiment 11

[0089] A method for preparing an ester-terminated siloxane comprises the following steps:

[0090] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound b and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor reaches 30 bar. The reaction temperature is controlled to 80°C, and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 2 is obtained by column chromatography separation, with a yield of 26% and a selectivity of 99%.

[0091]

[0092] The H-NMR spectrum characterization of the ester-terminated siloxane compound of formula 2: 1 HNMR (400MHz, CDCl 3 )δ7.53-7.46(m,4H),7.43-7.31(m,6H),3.60(s,6H),2.31-2.26(m,4H),1.16-1.09(m,4H),0.36(d,J=1.8Hz,6H).

[0093] Example 12

[0094] A method for preparing an ester-terminated siloxane comprises the following steps:

[0095] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound c and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor reaches 30 bar. The reaction temperature is controlled at 80°C and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 3 is obtained by column chromatography separation with a yield of 87% and a selectivity of 98%.

[0096]

[0097] The H-NMR spectrum characterization of the ester-terminated siloxane compound of formula 3: 1 HNMR (500MHz, CDCl 3 )δ7.55-7.49(m,4H),7.44-7.33(m,6H),3.63(s,3H),3.61(s,3H),2.37-2.31 (m,2H),2.28-2.21(m,2H),1.47-1.36(m,2H),0.94-0.84(m,2H),0.08(s,6H).

[0098] Embodiment 13

[0099] A method for preparing an ester-terminated siloxane comprises the following steps:

[0100] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound d and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor reaches 30 bar. The reaction temperature is controlled at 80°C and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 4 is obtained by column chromatography separation with a yield of 86% and a selectivity of 98%.

[0101]

[0102] The H-NMR spectrum characterization of the ester-terminated siloxane compound of formula 4: 1 H NMR (400 MHz, CDCl 3)δ7.49(d,J=8.4Hz,4H),7.01(d,J=8.4Hz,4H),3.65(s,6H),2.33-2.25(m,4H),0.91-0.84(m,4H),0.32(s,12H),0.08(s,12H).

[0103] Embodiment 14

[0104] A method for preparing an ester-terminated siloxane comprises the following steps:

[0105] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound e and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor reaches 30 bar. The reaction temperature is controlled to be 80°C, and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 5 is obtained by column chromatography separation, with a yield of 91% and a selectivity of 97%.

[0106]

[0107] The H-NMR spectrum characterization of the ester-terminated siloxane compound of formula 5: 1 H NMR (400 MHz, CDCl 3 )δ7.52(s,4H),3.65(s,6H),2.34-2.25(m,4H),0.92-0.85(m,4H),0.32(s,12H),0.09(s,12H).

[0108] Embodiment 15

[0109] A method for preparing an ester-terminated siloxane comprises the following steps:

[0110] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound f and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor reaches 30 bar. The reaction temperature is controlled at 80°C and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 6 is obtained by column chromatography separation with a yield of 93% and a selectivity of 98%.

[0111]

[0112] The H-NMR spectrum characterization of the ester-terminated siloxane compound of formula 6: 1 H NMR (400 MHz, CDCl 3)δ7.57-7.49(m,2H),7.41-7.33(m,3H),3.65(s,3H),2.33-2.26(m,2H),0.91-0.84(m,2H),0.32(s,6H),0.08(s,6H).

[0113] Example 16

[0114] A method for preparing an ester-terminated siloxane comprises the following steps:

[0115] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound g and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor reaches 30 bar. The reaction temperature is controlled at 80°C and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 7 is obtained by column chromatography separation with a yield of 73% and a selectivity of 54%.

[0116]

[0117] H-NMR characterization of ester-terminated siloxane compound 7: 1 HNMR (500MHz, CDCl 3 )δ3.66(s,12H),2.35-2.26(m,8H),0.89-0.83(m,8H),0.14-0.08(m,12H).

[0118] Embodiment 17

[0119] A method for preparing an ester-terminated siloxane comprises the following steps:

[0120] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound h and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor reaches 30 bar. The reaction temperature is controlled at 80°C and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 8 is obtained by column chromatography separation with a yield of 93% and a selectivity of 98%.

[0121]

[0122] The H-NMR spectrum characterization of the ester-terminated siloxane compound of formula 8: 1 HNMR (400MHz, CDCl 3)δ7.46-7.37(m,2H),6.97-6.87(m,2H),3.83(s,3H),3.65(s,3H),2.32-2.23(m ,2H),2.05-1.93(m,2H),0.99-0.85(m,4H),0.35(s,3H),0.09(d,J=1.5Hz,6H).

[0123] Embodiment 18

[0124] A method for preparing an ester-terminated siloxane comprises the following steps:

[0125] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound a and phenylethanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor reaches 30 bar. The reaction temperature is controlled to be 80°C, and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 9 is obtained by column chromatography separation, with a yield of 93% and a selectivity of 98%.

[0126]

[0127] The H-NMR spectrum characterization of the ester-terminated siloxane compound of formula 9: 1 H NMR (400 MHz, CDCl 3 )δ7.34-7.27(m,4H),7.26-7.19(m,6H),4.28(t,J=7.1Hz,4H),2.94(t,J=7.1Hz,4H),2.32-2.22(m,4H),0.87-0.77(m,4H),0.06(s,12H).

[0128] Embodiment 19

[0129] A method for preparing an ester-terminated siloxane comprises the following steps:

[0130] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound a and diacetone galactose are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor is 30 bar. The reaction temperature is controlled to 80°C, and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 10 is obtained by column chromatography separation, with a yield of 38% and a selectivity of 98%.

[0131]

[0132] The H-NMR spectrum characterization of the ester-terminated siloxane compound of formula 10: 1 H NMR (500 MHz, CDCl 3 )δ5.53(d,J=5.0Hz,2H),4.62(dd,J=7.9,5.4Hz,2H),4.33-4.28(m,4H),4.25-4.22(m,2H),4.20-4.15(m,2H),4.04 -3.99(m,2H),2.35-2.27(m,4H),1.51(s,6H),1.45(s,6H),1.33(d,J=5.4Hz,12H),0.88-0.81(m,4H),0.06(s,12H).

[0133] Embodiment 20

[0134] A method for preparing an ester-terminated siloxane comprises the following steps:

[0135] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated siloxane compound i and methanol are added into a reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After protection by nitrogen, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times. Then, carbon monoxide is charged until the pressure of the reactor reaches 30 bar. The reaction temperature is controlled at 80°C and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 11 is obtained by column chromatography separation with a yield of 99% and a selectivity of 98%.

[0136]

[0137] The H-NMR spectrum characterization of the ester-terminated siloxane compound of formula 11: 1 H NMR (400 MHz, CDCl 3 )δ3.68(s,24H),2.41-2.33(m,16H),0.99-0.92(m,16H).

[0138] Embodiment 21

[0139] A method for preparing an ester-terminated siloxane comprises the following steps:

[0140] A bidentate phosphine ligand such as formula V, divalent palladium, vinyl-terminated silicone oil j and methanol are added to the reactor in a molar ratio of 0.1:0.1:1:3, and 0.3M tetrahydrofuran is used as solvent. After nitrogen protection, the reactor is placed in an autoclave, and the gas is replaced with carbon monoxide three times, and then carbon monoxide is filled until the pressure of the reactor is 30 bar. The reaction temperature is controlled to be 80°C, and the reaction is carried out for 6 hours. After the reaction is completed, an ester-terminated siloxane compound such as formula 12 is obtained by column chromatography separation, with a yield of 93% and a selectivity of 95%. n≈42. Mn=4259.

[0141]

[0142] The H-NMR spectrum characterization of the ester-terminated siloxane compound of formula 12: 1 H NMR (400 MHz, CDCl 3 )δ3.66(s,6H),2.37-2.26(m,4H),0.96-0.75(m,4H),0.09(s,12H),0.07(s,242H). The gel permeation chromatogram of compound 12 is shown in Figure 1 The relative peak values ​​are shown in Table 1.

[0143] Table 1 Relative peak value table

[0144]

[0145] As shown in Table 1, the number average molecular weight (Mn) of the ester-terminated siloxane compound Formula 12 is 4259, and the polydispersity (Polydispersity) is between 1.3 and 1.5, and the polydispersity can still be maintained at a good level after the reaction.

[0146] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0147] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A method for preparing an ester-terminated siloxane, It is characterized in that The following steps are involved: Vinyl siloxane compounds and alcohol compounds are used as raw materials. Under the action of palladium-based metal catalysts and phosphine ligands, after adding solvents, a one-step hydrogenation reaction is carried out at 40°C to 180°C in a reaction gas atmosphere to obtain ester-terminated siloxanes, and the reaction gas is carbon monoxide.

2. The method for preparing the ester-terminated siloxane according to claim 1, It is characterized in that The molar ratio of the vinyl siloxane compound to the alcohol compound is 1:1-10.

3. The method for preparing the ester-terminated siloxane according to claim 1, It is characterized in that The amount of the palladium-based metal catalyst used is 0.1 mol% to 20 mol% of the total reaction system, and the molar ratio of the palladium-based metal catalyst to the phosphine ligand is 1 to 30:1 to 10.

4. The method for preparing the ester-terminated siloxane according to claim 1, It is characterized in that The pressure of the hydroesterification reaction is 1 bar to 40 bar, and the reaction time is 2 h to 72 h.

5. The method for preparing the ester-terminated siloxane according to claim 1, It is characterized in that An additive is added during the hydroesterification reaction, wherein the amount of the additive is 0 mol% to 20 mol% of the total reaction system, and the additive is selected from reagents that provide a proton source.

6. The method for preparing the ester-terminated siloxane according to claim 1, It is characterized in that The palladium-based metal catalyst is zero-valent palladium or divalent palladium-based metal.

7. The method for preparing the ester-terminated siloxane according to claim 1, It is characterized in that The phosphine ligand is a monodentate or bidentate phosphine ligand.

8. The method for preparing the ester-terminated siloxane according to claim 1, It is characterized in that The alcohol compound is selected from alcohol, phenol, polyol or sugar.

9. The method for preparing the ester-terminated siloxane according to claim 1, It is characterized in that The structural formula of the vinyl siloxane compound is shown in Formula I: Among them, R 1 , R 2 and R 3 Each is independently selected from hydrogen, C1-C8 alkyl, aryl, C1-C8 alkoxy, aryloxy, silyloxy, silyl, trifluoromethyl or hydroxyl.

10. The method for preparing the ester-terminated siloxane according to claim 1, It is characterized in that The solvent is selected from at least one of C1-C6 alkane solvents, C1-C6 alcohol solvents, aromatic hydrocarbon solutions, ether solutions, amide solutions or nitrile solvents.

Images