Preparation method of cyano-terminated siloxane

Abstract

The invention discloses a preparation method of cyano-terminated siloxane, and belongs to the technical field of synthesis of terminated siloxane. Comprising the following steps: by taking a vinyl siloxane compound and a hydrocyanic acid compound as raw materials, adding a solvent under the action of a nickel-based metal catalyst and a bidentate phosphite ligand, and reacting at 40-180 DEG C by a one-step hydrogen cyanide method in a protective gas atmosphere to obtain the cyano-terminated siloxane. The cyano-terminated siloxane is prepared through the hydrocyanation reaction, and the method has the advantages that a precious metal platinum catalyst is not used, raw materials and the catalyst are cheap and easy to obtain, the step economy is high, and the reaction selectivity is high; according to the method for preparing the cyano-terminated siloxane, the technological process is simplified, the raw material cost, the equipment cost and the production cost are reduced, and certain feasibility is achieved for achieving industrial production of the cyano-terminated siloxane; the method provides a cheap, efficient and high-selectivity new way for the preparation of cyano-terminated siloxane.

Description

Technical Field

[0001] The present invention relates to the technical field of end-capped siloxane synthesis, and relates to a method for preparing cyano-end-capped siloxane, and specifically to a method for preparing cyano-end-capped siloxane by hydrocyanation of vinyl siloxane using nickel catalysis. Background Art

[0002] Organic silicon materials generally refer to compounds containing Si-C bonds and at least one organic group directly connected to the silicon atom. Because of their higher thermal stability, better flexibility and hydrophobicity, they are widely used in the fields of construction, machinery manufacturing, daily chemicals and textiles, and are known as "technological catalysts" and "industrial vitamins". There are many types of organic silicon materials, including polysiloxane, polycarbosilane, polynitrogen silane, etc. Among them, polysiloxane is the most widely used type of organic silicon compounds, accounting for more than 90%.

[0003] Polysiloxane refers to a class of compounds containing Si-O-Si bonds and having a unique semi-inorganic and semi-organic structure. Due to the long bond length and large bond angle of the silicon-oxygen bond, it has excellent molecular chain flexibility. Due to the high bond energy of the silicon-oxygen bond, it has excellent heat resistance and weather resistance, and has the prospect of being used in special environmental conditions. Introducing functional groups into the structure of polysiloxanes can usually obtain special properties. This strategy is an important method for siloxane modification. For example, amino, hydroxyl, acyloxy, carboxyl, etc., while retaining their own characteristics, different functional groups also give siloxanes various unique properties such as stable chemical properties and good lubrication and film formation. Therefore, it has broader application prospects in the fields of cosmetics, textiles, leather, and automobiles. Hydrosilylation is a traditional synthesis method for functionalized siloxanes. However, this method has obvious limitations, such as: using precious metals as catalysts, the reaction requires pre-protection and deprotection, and the step economy is poor. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing cyano-terminated siloxane, which uses a one-step hydrocyanation reaction of vinyl siloxane to efficiently and highly selectively prepare cyano-terminated siloxane, greatly shortening the process flow and reducing production costs, equipment investment and energy consumption.

[0005] In order to achieve the above purpose, the technical solution adopted in this application is:

[0006] The object of the present invention is to provide a method for preparing a cyano-terminated siloxane, comprising the following steps:

[0007] Vinyl siloxane compounds and hydrocyanic acid compounds are used as raw materials, a nickel-based metal catalyst and a bidentate phosphite ligand are used, a solvent is added, and a one-step hydrocyanation reaction is carried out at 40°C to 180°C in a protective gas atmosphere to obtain cyano-terminated siloxane.

[0008] The structural formula of the cyano-terminated siloxane is shown in Formula II or Formula II-1:

[0009]

[0010] Among them, R 1 , R 2 , R 3 Each is independently selected from hydrogen, C1-C8 alkyl, aryl, C1-C8 alkoxy, aryloxy, silyloxy, silyl, trifluoromethyl, carbonyl, C1-C8 alkenyl, C1-C8 alkynyl or hydroxyl.

[0011] Furthermore, the molar ratio of the vinyl siloxane to the hydrocyanic acid compound is 1:1-10.

[0012] Furthermore, the amount of the nickel-based metal catalyst used is 0.1 mol% to 20 mol% of the total reaction system, and the molar ratio of the nickel-based metal catalyst to the bidentate phosphite ligand is 1-30:1-10.

[0013] Furthermore, the reaction time of the hydrocyanation method is 2h to 72h.

[0014] Furthermore, the hydrocyanic acid compound is hydrocyanic acid gas, hydrocyanic acid solution or butanone cyanohydrin.

[0015] Furthermore, the nickel-based metal catalyst is zero-valent nickel or divalent nickel-based metal.

[0016] Furthermore, the bidentate phosphite ligand structure is shown in III:

[0017]

[0018] Among them, R 1 -R 16 The groups are independently selected from hydrogen, C1-C8 alkyl, C1-C8 alkoxy, silicon, halogen, benzyl and aryl.

[0019] Furthermore, R 4 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 and R 16 Not hydrogen at the same time.

[0020] Furthermore, the structural formula of the vinyl siloxane compound is as shown in Formula I:

[0021]

[0022] Among them, R 1 , R 2 , R 3 Each is independently selected from hydrogen, C1-C8 alkyl, aryl, C1-C8 alkoxy, aryloxy, silyloxy, silyl, trifluoromethyl, carbonyl, C1-C8 alkenyl, C1-C8 alkynyl or hydroxyl.

[0023] Furthermore, the solvent is a C1-C6 alkane solvent, a C1-C6 alcohol solvent, an aromatic hydrocarbon solution, an ether solution, an amide solution, a nitrile solvent, or a combination thereof.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] The present invention realizes the efficient and highly selective preparation of cyano-terminated siloxane by one-step hydrocyanation reaction of vinyl siloxane, greatly shortens the process flow, and reduces production cost, equipment investment and energy consumption. The advantages of the method are: the vinyl siloxane compound and nickel catalyst as raw materials are cheap and easy to obtain, the selectivity and yield of the target product are both high, the experimental operation is simple, and no side reaction is generated. The method can be carried out under the condition of no Lewis acid as a co-catalyst, reducing production cost and equipment loss. The method can use equivalents such as butanone cyanide source instead of highly toxic hydrocyanic acid, which is not only conducive to storage and convenient feeding operation, but also can reduce catalyst recovery costs and potential safety risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is the gel permeation chromatogram of the compound of formula II-1 of the present invention. DETAILED DESCRIPTION

[0027] 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.

[0028] 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.

[0029] The cyano group is an important synthon in organic synthesis and can be easily converted into functional groups such as acids, esters, aldehydes, amines and amides. If a method for efficiently synthesizing cyano-terminated siloxanes can be developed, the resulting product can also achieve the synthesis of a variety of functionalized siloxanes through cyano conversion. Although transition metal-catalyzed olefin hydrocyanation is the most direct and atom-economical method for preparing cyanide-containing compounds, however, this strategy has not yet been used for the preparation of functionalized siloxanes at home and abroad. Therefore, if energy innovation is made, breaking through the traditional idea of ​​synthesizing functionalized siloxanes by precious metal-catalyzed functionalized olefin hydrosilylation reaction, it is of great research value to develop a hydrogen functionalization reaction using abundant metals as catalysts and simple and easily available olefins as substrates to synthesize functionalized siloxanes. Based on this, the present invention provides a method for preparing cyano-terminated siloxanes, comprising the following steps:

[0030] Vinyl siloxane compounds and hydrocyanic acid compounds are used as raw materials, a nickel-based metal catalyst and a bidentate phosphite ligand are used, a solvent is added, and a one-step hydrocyanation reaction is carried out at 40°C to 180°C in a protective gas atmosphere to obtain cyano-terminated siloxane.

[0031] The structural formula of the cyano-terminated siloxane is shown in Formula II or Formula II-1:

[0032]

[0033] Among them, R 1 , R 2 and R 3 Each of them is independently selected from one of the group including but not limited to hydrogen, C1-C8 alkyl, aryl, C1-C8 alkoxy, aryloxy, siloxy, silyl, trifluoromethyl, carbonyl, C1-C8 alkenyl, C1-C8 alkynyl and hydroxyl.

[0034] The synthetic route of cyano-terminated siloxane is as follows:

[0035]

[0036] The reaction mechanism is shown below:

[0037]

[0038] Nickel generates nickel complex I under the action of phosphine ligand, and oxidative addition with HCN generates intermediate II, intermediate II migrates and inserts into alkenyl silicon to form intermediate III, and finally obtains cyanosiloxane through reduction elimination to complete the cycle. Based on this, the present invention uses vinyl siloxane one-step hydrocyanation reaction to efficiently and selectively prepare cyano-terminated siloxane, which greatly shortens the process flow, reduces production cost, equipment investment and energy consumption; wherein the vinyl siloxane compound and nickel catalyst used as raw materials are cheap and easy to obtain, the selectivity and yield of the target product are both high, the experimental operation is simple, and no side reaction is generated. It can be carried out without Lewis acid as a co-catalyst, reducing production cost and equipment loss; butanone cyanide source and other equivalents can be used instead of highly toxic hydrocyanic acid, which is not only conducive to storage and convenient feeding operation, but also can reduce catalyst recovery cost and potential safety risks.

[0039] In some specific embodiments, the molar ratio of the vinyl siloxane to the hydrocyanic acid compound is 1:1 to 10. As a preferred embodiment of the present invention, the molar ratio of the vinyl siloxane to the hydrocyanic acid compound is 1:1.5 to 6.

[0040] In some specific embodiments, the amount of the nickel-based metal catalyst is 0.1 mol% to 20 mol% of the total reaction system, and the molar ratio of the nickel-based metal catalyst to the bidentate phosphite ligand is 1 to 30: 1 to 10. As a preferred embodiment of the present invention, the amount of the nickel-based metal catalyst is 5 mol% to 10 mol% of the total reaction system; the molar ratio of the nickel-based metal catalyst to the bidentate phosphite ligand is 1: 1 to 2.

[0041] In some specific embodiments, the reaction time of the hydrocyanation method is 2 hours to 72 hours. As a preferred embodiment of the present invention, the reaction time of the hydrocyanation method is 12 hours to 24 hours.

[0042] In some specific embodiments, the hydrocyanic acid compound includes but is not limited to hydrocyanic acid gas, hydrocyanic acid solution or butanone cyanohydrin.

[0043] In some specific embodiments, the nickel-based metal catalyst is zero-valent nickel or divalent nickel-based metal.

[0044] In some specific embodiments, the bidentate phosphite ligand structure is shown in III:

[0045]

[0046] Among them, R 1 -R 16 The groups independently include but are not limited to one of hydrogen, C1-C8 alkyl, C1-C8 alkoxy, silicon, halogen, benzyl, and aryl. 4 , R 8 , R9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 and R 16 Not at the same time hydrogen; R 1 -R 16 The groups include, but are not limited to, hydrogen, C1-C8 alkyl, alkoxy, silicon, halogen, benzyl, and aryl. 1 -R 16 The substituent groups can be randomly combined; in the ligand formula III, R 1 With R 2 , R 2 With R 3 , R 3 With R 4 , R 5 With R 6 , R 6 With R 7 , R 7 With R 8 , R 9 With R 10 , R 10 With R 11 , R 11 With R 12 , R 12 With R 13 , R 13 With R 14 , R 14 With R 15 , R 15 With R 16 Including but not limited to the cyclization of all-carbon structure or non-all-carbon structure into conjugated structure or non-conjugated structure. In the specific ligand, it can be randomly combined. As a preferred embodiment of the present invention, as shown in formula IV, R 4 With R 8 This includes but is not limited to cyclization of all-carbon chains or non-all-carbon structures into conjugated structures or non-conjugated structures.

[0047]

[0048] As a preferred embodiment of the present invention, the bidentate phosphite ligand structure contains all monomers of existing racemates, enantiomers, diastereomers and atropisomers. The bidentate phosphite ligand can use a single isomer or an isomer mixture with a specific stereo configuration.

[0049] In some specific embodiments, the structural formula of the vinyl siloxane compound is as shown in Formula I:

[0050]

[0051] Among them, R 1 , R 2 and R 3 Each of them is independently selected from one of the group including but not limited to hydrogen, C1-C8 straight or branched alkyl, aryl, alkoxy, aryloxy, siloxy, silicon, trifluoromethyl, carbonyl, alkenyl, alkynyl and hydroxyl.

[0052] Furthermore, the solvent includes but is not limited to C1-C6 alkane solvents, C1-C6 alcohol solvents, aromatic hydrocarbon solutions, ether solutions, amide solutions, nitrile solvents, or combinations thereof.

[0053] The invention is further described below through specific examples.

[0054] Example 1

[0055] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0056] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 84% and a selectivity of 97%.

[0057]

[0058] The nuclear magnetic hydrogen spectrum characterization of the cyano-terminated siloxane compound formula 1 is as follows: 1 H NMR (500MHz, Chloroform-d) δ2.35 (t, J = 6.4 Hz, 4H), 0.94 (t, J = 6.4 Hz, 4H), 0.16 (s, 12H).

[0059] Example 2

[0060] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0061] A bidentate phosphite ligand such as Formula VI, zero-valent nickel, a vinyl siloxane compound such as Formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent (0.3 mL). The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as Formula 1 is obtained by column chromatography separation with a yield of 76% and a selectivity of 65%.

[0062]

[0063] Example 3

[0064] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0065] A bidentate phosphite ligand such as Formula VII, zero-valent nickel, a vinyl siloxane compound such as Formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as Formula 1 is obtained by column chromatography separation with a yield of 86% and a selectivity of 81%.

[0066]

[0067] Example 4

[0068] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0069] A bidentate phosphite ligand such as formula VIII, zero-valent nickel, a vinyl siloxane compound such as formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 62% and a selectivity of 61%.

[0070]

[0071] Example 5

[0072] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0073] A bidentate phosphite ligand such as Formula IX, zero-valent nickel, a vinyl siloxane compound such as Formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as Formula 1 is obtained by column chromatography separation with a yield of 77% and a selectivity of 76%.

[0074]

[0075] Example 6

[0076] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0077] A bidentate phosphite ligand such as formula X, zero-valent nickel, a vinyl siloxane compound such as formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 60% and a selectivity of 52%.

[0078]

[0079] Example 7

[0080] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0081] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled to 80°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 30% and a selectivity of 90%.

[0082] Example 8

[0083] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0084] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 100°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 77% and a selectivity of 86%.

[0085] Example 9

[0086] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0087] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled to be 100°C and the reaction is carried out for 12 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 64% and a selectivity of 82%.

[0088] Example 10

[0089] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0090] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 36 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 59% and a selectivity of 95%.

[0091] Embodiment 11

[0092] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0093] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 72 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 59% and a selectivity of 99%.

[0094] Example 12

[0095] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0096] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.2:0.2:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 86% and a selectivity of 87%.

[0097] Embodiment 13

[0098] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0099] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.05:0.05:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 68% and a selectivity of 87%.

[0100] Embodiment 14

[0101] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0102] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.05:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 45% and a selectivity of 91%.

[0103] Embodiment 15

[0104] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0105] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula a and butanone cyanohydrin are added into a reactor in a molar ratio of 0.05:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 1 is obtained by column chromatography separation with a yield of 79% and a selectivity of 83%.

[0106] Example 16

[0107] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0108] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula b and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 2 is obtained by column chromatography separation with a yield of 81% and a selectivity of 96%.

[0109]

[0110] The nuclear magnetic hydrogen spectrum characterization of the cyano-terminated siloxane compound 2: 1 HNMR (400MHz, Chloroform-d) δ7.51–7.36 (m, 10H), 2.30-2.21 (m, 4H), 1.22-1.15 (m, 4H), 0.45 (d, J = 1.6Hz, 6H).

[0111] Embodiment 17

[0112] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0113] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula c and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 3 is obtained by column chromatography separation with a yield of 73% and a selectivity of 97%.

[0114]

[0115] The nuclear magnetic hydrogen spectrum characterization of the cyano-terminated siloxane compound formula 3: 1 H NMR (500MHz, Chloroform-d) δ7.55–7.38(m,10H),2.32(t,J=8.3Hz,2H),2.21(t,J=8.2Hz,2H),1.49(t,J=7.8Hz,2H),0.93(t,J=8.1Hz,2H),0.16(s,6H).

[0116] Embodiment 18

[0117] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0118] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula d and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 4 is obtained by column chromatography separation with a yield of 86% and a selectivity of 90%.

[0119]

[0120] The nuclear magnetic hydrogen spectrum characterization of the cyano-terminated siloxane compound formula 4: 1 H NMR (400MHz, Chloroform-d) δ7.58–7.50(m,4H),7.49–7.43(m,2H),7.43–7.36(m,4H),2.25–2.14(m,4H),0.98–0.87(m,4H),0.16(s,12H).

[0121] Embodiment 19

[0122] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0123] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula e and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 5 is obtained by column chromatography separation with a yield of 87% and a selectivity of 94%.

[0124]

[0125] The nuclear magnetic hydrogen spectrum characterization of the cyano-terminated siloxane compound formula 5: 1 H NMR (400MHz, Chloroform-d) δ7.50 (d, J = 8.4Hz, 4H), 7.03 (d, J = 8.4Hz, 4H), 2.29 (t, J = 8.3Hz, 4H), 0.93 (t, J = 8.3Hz, 4H), 0.35 (s, 12H), 0.14 (s, 12H).

[0126] Embodiment 20

[0127] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0128] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula f and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 6 is obtained by column chromatography separation with a yield of 73% and a selectivity of 93%.

[0129]

[0130] The nuclear magnetic hydrogen spectrum characterization of the cyano-terminated siloxane compound formula 6: 1 H NMR (500MHz, Chloroform-d) δ7.53 (s, 4H), 2.28 (t, J = 8.3 Hz, 4H), 0.93 (t, J = 8.3 Hz, 4H), 0.35 (s, 12H), 0.14 (s, 12H).

[0131] Embodiment 21

[0132] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0133] A bidentate phosphite ligand such as Formula V, zero-valent nickel, a vinyl siloxane compound such as Formula g and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:1.5. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as Formula 7 is obtained by column chromatography separation with a yield of 86% and a selectivity of 93%.

[0134]

[0135] The nuclear magnetic hydrogen spectrum characterization of the cyano-terminated siloxane compound formula 7: 1 H NMR (400MHz,) δ7.57-7.49(m,2H),7.44-7.34(m,3H),2.27(t,J=8.3Hz,2H),0.93(t,J=8.3Hz,2H),0.36(s,6H),0.14(s,6H).

[0136] Embodiment 22

[0137] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0138] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula g and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:1.5. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 8 is obtained by column chromatography separation with a yield of 59% and a selectivity of 99%.

[0139]

[0140] The nuclear magnetic hydrogen spectrum characterization of the cyano-terminated siloxane compound formula 8: 1 H NMR (500MHz, Chloroform-d) δ4.26-4.17 (m, 3H), 2.42-2.33 (m, 2H), 1.19 (d, J = 6.1Hz, 18H), 0.99-0.90 (m, 2H).

[0141] Embodiment 23

[0142] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0143] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula I and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:4.5. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 9 is obtained by column chromatography separation with a yield of 74% and a selectivity of 91%.

[0144]

[0145] The nuclear magnetic hydrogen spectrum characterization of the cyano-terminated siloxane compound formula 9: 1 H NMR (500MHz, Chloroform-d) δ2.49-2.35(m,6H),1.05-0.89(m,6H),0.31-0.20(m,9H).

[0146] Embodiment 24

[0147] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0148] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula j and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:6. Under a nitrogen atmosphere, 0.3 M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula 10 is obtained by column chromatography separation with a yield of 78% and a selectivity of 82%.

[0149]

[0150] The nuclear magnetic hydrogen spectrum characterization of the cyano-terminated siloxane compound formula 10: 1 H NMR (400MHz, Chloroform-d) δ2.50-2.32(m,8H),1.04-0.89(m,8H),0.33-0.18(m,12H).

[0151] Embodiment 25

[0152] A method for preparing a cyano-terminated siloxane comprises the following steps:

[0153] A bidentate phosphite ligand such as formula V, zero-valent nickel, a vinyl siloxane compound such as formula K and butanone cyanohydrin are added into a reactor in a molar ratio of 0.1:0.1:1:3. Under a nitrogen atmosphere, 0.3M toluene is used as a solvent. The reaction temperature is controlled at 120°C and the reaction is carried out for 24 hours. After the reaction is completed, a cyano-terminated siloxane compound such as formula II-1 is obtained by column chromatography with a yield of 58%, a selectivity of 82%, and Mn=6892.

[0154]

[0155] The H-NMR spectrum characterization of the polycyano-terminated siloxane compound of formula II-1: 1 HNMR (500MHz, Chloroform-d) δ2.40 (t, J = 8.3Hz, 4H), 0.95 (m, J = 8.3Hz, 4H), 0.16 (s, 12H), 0.07 (s, 441H). The gel permeation chromatogram of compound II-1 is shown in Figure 1 The relative peak value table is shown in Table 1.

[0156] Table 1 Relative peak value table

[0157]

[0158] As shown in Table 1, the number average molecular weight (Mn) of the compound of formula II-1 is 6892, and the polydispersity is between 1.3 and 1.5, and the polydispersity can still be maintained at a good level after the reaction.

[0159] 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.

[0160] 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 a cyano-terminated siloxane, characterized in that: The following steps are involved: Vinyl siloxane compounds and hydrocyanic acid compounds are used as raw materials, under the action of nickel-based metal catalysts and bidentate phosphite ligands, solvents are added, and a one-step hydrocyanation reaction is carried out at 40°C to 180°C in a protective gas atmosphere to obtain cyano-terminated siloxane.

2. The method for preparing a cyano-terminated siloxane according to claim 1, characterized in that: The molar ratio of the vinyl siloxane to the hydrocyanic acid compound is 1:1-10.

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

4. The method for preparing cyano-terminated siloxane according to claim 1, characterized in that: The reaction time of the hydrocyanation method is 2h to 72h, and the protective gas is nitrogen.

5. The method for preparing cyano-terminated siloxane according to claim 1, characterized in that: The hydrocyanic acid compound is hydrocyanic acid gas, hydrocyanic acid solution or butanone cyanohydrin.

6. The method for preparing cyano-terminated siloxane according to claim 1, characterized in that: The nickel-based metal catalyst is zero-valent nickel or divalent nickel-based metal.

7. The method for preparing cyano-terminated siloxane according to claim 1, characterized in that: The bidentate phosphite ligand structure is shown in III: Among them, R 1 -R 16 The groups are independently selected from hydrogen, C1-C8 alkyl, C1-C8 alkoxy, silicon and aryl.

8. The method for preparing the cyano-terminated siloxane according to claim 7, characterized in that: R 4 , R 8 , R 9 , R 10 , R 11 , R 12 , R 13 , R 14 , R 15 and R 16 Not hydrogen at the same time.

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

10. The method for preparing cyano-terminated siloxane according to claim 1, characterized in that: The solvent is 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.

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