A process for the preparation of isopropyl tris(dimethylamino) tin

Abstract

The application discloses a preparation method of isopropyl tris(dimethylamino) tin, which comprises the following steps: under an inert gas atmosphere, tin dihalide and tetra(dimethylamino) tin are placed in an organic solvent to react, a mixed solution containing tris(dimethylamino) tin halide and dimethylamino tin halide dimer is obtained, the mixed solution is subjected to separation treatment, the dimethylamino tin halide dimer is removed, and tris(dimethylamino) tin halide is obtained; the tris(dimethylamino) tin halide is placed in an organic solvent to react with an isopropylating agent, and the obtained reaction product is subjected to distillation and purification, so that the isopropyl tris(dimethylamino) tin is obtained. The raw materials used in the application have a wide source and low cost, and the treatment process is simple; the preparation method only comprises two core reactions and one separation and purification, is short in reaction period, simple in operation, easy to be industrialized, and capable of stably preparing high-purity isopropyl tris(dimethylamino) tin.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of organic tin compound preparation, in particular to a preparation method of isopropyl tris(dimethylamino) tin. BACKGROUND

[0002] Atomic layer deposition (ALD) technology has become a core technology for preparing advanced nanometer thin film materials due to its atomic level film thickness control, excellent three-dimensional conformality and large-area uniformity. A high-activity tin source precursor is a key material for ALD deposition of tin-based semiconductor thin films, and tin-based semiconductors (especially tin oxide) have great application potential in the fields of sensors and photovoltaic devices due to their wide band gap, high carrier mobility and excellent chemical and thermal stability. Among them, isopropyl tris(dimethylamino) tin has the core characteristics of high activity, low boiling point and high vapor pressure, which can be applied to the preparation of tin-based semiconductor thin films as a tetravalent tin source precursor.

[0003] However, the existing preparation methods of isopropyl tris(dimethylamino) tin have significant defects and cannot meet the actual needs. The first method uses isopropyl tin chloride and dimethylamino lithium as raw materials, and the core is the preparation of isopropyl tin chloride: the reaction method of tin tetrachloride and tetra(isopropyl) tin has the defects of high raw material cost or complicated synthesis steps and long time consumption; the redistribution reaction method of triphenyl isopropyl tin and tin tetrachloride is prone to incomplete phenyl exchange and difficult impurity separation; and when triphenyl isopropyl tin and iodine or iodine monochloride are used, iodine-related substances can corrode equipment, cause ALD process "memory effect" to contaminate products, increase cleaning difficulty, and also may corrode active metal substrates. The second method uses dimethylamino tin dimer and 2-iodopropane to react, and the theoretical yield of the target product is only 50%, the by-product needs to be recovered and re-reacted, the process is complicated, the reaction needs to be continued for 70 h at 60 DEG C, the efficiency is extremely low, and there is also the problem of iodine-related pollution. The third method uses tin dichloride and dimethylamino lithium to prepare tris(dimethylamino) lithium tin, and then reacts with 2-iodopropane to prepare isopropyl tris(dimethylamino) tin, the first step reaction needs to be continued for 60 h at 55 DEG C, and the combination stability of tin and lithium is poor, which is easy to generate by-products, and also has the problems of equipment corrosion and product contamination due to the use of iodine-containing compounds. SUMMARY

[0004] The purpose of the present application is to solve the technical problems that the existing methods generally have a series of defects caused by iodine-containing compounds, the reaction time is long, the process is complicated, and the yield and purity are difficult to balance, and to provide a preparation method of isopropyl tris(dimethylamino) tin, which does not need to rely on iodine-containing raw materials, has a short reaction period, is simple to operate, can stably obtain high-purity isopropyl tris(dimethylamino) tin, and meets the application requirements of ALD process for tin source precursors.

[0005] The above object of the present application is achieved by the following technical solutions.

[0006] A preparation method of isopropyl tris(dimethylamino) tin, comprising the following steps:

[0007] S1. In an inert gas atmosphere, tin dihalide and tin tetra(dimethylamino) are reacted in an organic solvent to obtain a mixed solution containing tris(dimethylamino) tin halide and dimethylamino tin halide dimer, the mixed solution is subjected to separation treatment to remove the dimethylamino tin halide dimer, and tris(dimethylamino) tin halide is obtained; the tin dihalide is tin dichloride and / or tin dibromide;

[0008] S2. In an inert gas atmosphere, the tris(dimethylamino) tin halide is reacted with an isopropylating agent in an organic solvent, and the obtained reaction product is subjected to distillation purification to obtain the isopropyl tris(dimethylamino) tin; the isopropylating agent is selected from one or more of isopropylmagnesium chloride, isopropylmagnesium bromide and isopropyl lithium.

[0009] The present application selects high-activity tin tetra(dimethylamino) and low-activity tin dihalide as reaction raw materials, and the two react in accordance with the rule of ligand exchange one by one to generate tris(dimethylamino) tin halide intermediates and dimethylamino tin halide dimer byproducts. The present application realizes efficient separation by using the essential difference in solubility of the intermediates and byproducts in n-hexane: tris(dimethylamino) tin halide has good hydrophobicity and compatibility with n-hexane due to the three dimethylamino ligands in the molecular structure, and has large solubility; and the dimethylamino tin halide dimer is completely insoluble in the non-polar solvent n-hexane due to the formation of a dimer structure, the significant enhancement of molecular polarity, and the increase of steric hindrance. By means of desolventization, n-hexane dissolution and filtration, the byproducts can be completely removed, and high-purity tris(dimethylamino) tin halide intermediates are obtained. When the high-purity tris(dimethylamino) tin halide intermediates react with an isopropylating agent, the halide ions in the intermediates are replaced by isopropyl ligands, and since the intermediates have stable structure and high purity, no extra side reactions occur in the reaction, and high-purity isopropyl tris(dimethylamino) tin can be obtained through distillation purification, the whole process does not require iodine-containing raw materials, and the reaction steps are simple.

[0010] Further, in S1, the inert gas is nitrogen or argon.

[0011] Further, in S1, the molar ratio of the tin dihalide to the tin tetra(dimethylamino) is (0.8-1.2):1.

[0012] Further, in S1, the ratio of the amount of the tin dihalide to the amount of the organic solvent is 0.1 mol: 100-200 mL.

[0013] Further, in S1, the organic solvent is selected from one or more of tetrahydrofuran, ethylene glycol dimethyl ether and diethyl ether.

[0014] Further, in S1, the reaction temperature is 25-85 ℃ and the reaction time is 10-50 h.

[0015] Further, in S1, the separation process is specifically as follows: first, remove the organic solvent in the mixed solution, then add n-hexane to dissolve the tris(dimethylamino) tin halide, and then filter out the dimethylamino tin halide dimer.

[0016] The removal of the organic solvent can avoid the interference of the solvent on the solubility difference, ensure that the tris(dimethylamino) tin halide can be fully dissolved in n-hexane, and the dimethylamino tin halide dimer is completely precipitated, thereby realizing efficient separation; if n-hexane is directly added to the original solvent, the solubility difference will be reduced due to the change in solvent polarity, and the by-product cannot be completely removed.

[0017] Further, in S2, the inert gas is nitrogen or argon.

[0018] Further, in S2, the molar ratio of the tris(dimethylamino) tin halide to the isopropylating agent is (0.8-1.2):1.

[0019] Further, in S2, the amount ratio of the tris(dimethylamino) tin halide to the organic solvent is 0.1 mol: 80-150 mL.

[0020] Further, in S2, the organic solvent is selected from one or more of tetrahydrofuran, ethylene glycol dimethyl ether and diethyl ether.

[0021] Further, in S2, the reaction temperature is 40-80 ℃ and the reaction time is 3-5 h.

[0022] The isopropylating agent has high activity, so the reaction temperature is controlled at 40-80 ℃, which can ensure that the reaction proceeds quickly and the isopropyl ligand is not decomposed due to too high temperature.

[0023] Further, in S2, the distillation purification adopts two-step vacuum distillation.

[0024] Further, the temperature and vacuum degree of the two-step vacuum distillation are 30-80 ℃ and 1-5 Torr, respectively.

[0025] Preferably, the temperature and vacuum degree of the two-step vacuum distillation are 40-70 ℃ and 1-3 Torr, respectively.

[0026] The temperature and vacuum degree parameters of the two-step vacuum distillation can be flexibly adjusted according to actual needs, which can be consistent or different from each other.

[0027] The above technical scheme of the present application has the following beneficial effects compared with the prior art:

[0028] 1. The present application selects high-activity tetra(dimethylamino)tin and low-activity tin dichloride to react, avoids the problem of reaction out of control caused by strong acidity and over-high activity of tin tetrachloride, realizes directional exchange of ligands, does not need to carry out multi-step chlorine displacement, greatly shortens the reaction period, and significantly improves the stability of the product. Under anhydrous and anaerobic conditions, through precise control of the reaction parameters and separation steps, the yield of the final product can reach 80%-85%, and the metal purity is as high as 6N (99.9999%).

[0029] 2. The present application does not need to use iodine-containing raw materials, avoids the corrosion of iodine vapor, hydrogen iodide and other substances to the equipment, the "memory effect" of the process and the damage to the base material, reduces the equipment maintenance cost and the process control difficulty, and avoids the influence of iodide impurities on the purity of the product.

[0030] 3. The raw materials used in the present application are widely available and low in cost, and the processing flow is simple; the entire preparation method only includes two core reactions and one separation and purification, is simple to operate and easy to scale up, and is suitable for industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0031] Figure 1 Nuclear magnetic hydrogen spectrum of isopropyl tris(dimethylamino)tin prepared in Example 1. DETAILED DESCRIPTION

[0032] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items.

[0033] The present application provides a preparation method of isopropyl tris(dimethylamino)tin, comprising the following steps:

[0034] S1. In an inert gas atmosphere, tin dihalide and tetra(dimethylamino)tin are placed in an organic solvent to react, to obtain a mixed solution containing tris(dimethylamino)tin halide and dimethylamino tin halide dimer, the mixed solution is subjected to separation treatment to remove the dimethylamino tin halide dimer, to obtain tris(dimethylamino)tin halide; the tin dihalide is tin dichloride and / or tin dibromide;

[0035] S2. The tris(dimethylamino)tin halide is reacted with an isopropylating agent in an organic solvent under an inert gas atmosphere, and the obtained reaction product is distilled and purified to obtain the isopropyl tris(dimethylamino)tin; the isopropylating agent is isopropylmagnesium chloride, isopropylmagnesium bromide or isopropyl lithium.

[0036] In one embodiment of the present application, the method for preparing isopropyl tris(dimethylamino)tin comprises the following steps:

[0037] S1. The tin dichloride is placed in a reaction bottle in a glove box, and after being taken out, a nitrogen atmosphere is built by a double-tube, and then anhydrous and oxygen-free tetrahydrofuran is added to the reaction bottle under the atmosphere, and then tetra(dimethylamino)tin is added, and stirred and reacted at 25-85 ℃ for 10-50 h, and the reaction time can be shortened by heating; after the reaction is completed, the organic solvent is removed under vacuum, and the intermediate tris(dimethylamino)tin chloride is dissolved in n-hexane, and the insoluble by-product dimethylamino tin chloride dimer is removed by filtration in the glove box;

[0038] S2. The solvent of the filtrate after filtration is removed, and anhydrous and oxygen-free tetrahydrofuran is added again, and isopropylmagnesium chloride is slowly added under a nitrogen atmosphere, and reacted at 40-80 ℃ for 3-5 h; after the reaction is completed, the solvent is removed, and the characteristics of the system with less solid content are used, and short-path vacuum distillation is carried out under the conditions of 30-80 ℃ and 1-5 Torr reduced pressure to obtain the crude isopropyl tris(dimethylamino)tin, and the crude product is further distilled and purified under the conditions of 30-80 ℃ and 1-5 Torr reduced pressure, and finally the high-purity finished product isopropyl tris(dimethylamino)tin is obtained.

[0039] In one embodiment of the present application, the reaction route for preparing isopropyl tris(dimethylamino)tin is as follows:

[0040] .

[0041] The present application will be further described in conjunction with the drawings and specific embodiments so that those skilled in the art can better understand the present application and implement it, but the embodiments are not limiting to the present application.

[0042] In the following examples, the experimental methods used are conventional methods unless otherwise specified, and the materials, reagents, etc. used are commercially available unless otherwise specified.

[0043] Example 1

[0044] A method for preparing isopropyl tris(dimethylamino)tin comprises the following steps:

[0045] S1. In a glove box, tin dichloride (18.96 g, 0.1 mol) was weighed into a reaction flask, after which a nitrogen atmosphere was established using a double manifold. Anhydrous and oxygen-free tetrahydrofuran (150 mL) was added to the reaction flask under a nitrogen atmosphere. Tetra(dimethylamino)tin (29.5 g, 0.1 mol) was added under a nitrogen atmosphere, and the reaction was stirred at 60 °C for 25 h. After the reaction was complete, the solvent was removed under vacuum, and n-hexane (150 mL) was added to dissolve the intermediate product, tris(dimethylamino)tin chloride, which was filtered in a glove box to remove dimethylamino tin chloride dimer;

[0046] S2. The filtered filtrate was dried by removing the solvent, and anhydrous and oxygen-free tetrahydrofuran (100 mL) was added. Isopropylmagnesium chloride solution (2.0 M, 50 mL, solvent: tetrahydrofuran) was slowly added under a nitrogen atmosphere, and the reaction was carried out at 60 °C for 4 h. After the reaction was complete, the solvent was removed, and isopropyl tris(dimethylamino)tin was distilled under short-path reduced pressure (2 Torr) at 60 °C to obtain a crude product. The crude product was distilled under reduced pressure (2 Torr) at 40 °C to obtain a colorless solution of the finished product, isopropyl tris(dimethylamino)tin (25.00 g, 0.085 mol), with a yield of 85 %, a metal purity of 6N, and the following nuclear magnetic resonance data: 1 H NMR (400 MHz, C6D6): δ (ppm) = 1.26-1.27 (d, 6H, C(CH3)2), 1.61 (h, 1H, C(CH3)2), 2.85 (s, 18H, N(CH3)2), and the nuclear magnetic hydrogen spectrum is as shown in Figure 1 .

[0047] Example 2

[0048] A method for preparing isopropyl tris(dimethylamino)tin, comprising the following steps:

[0049] S1. In a glove box, tin dichloride (18.96 g, 0.1 mol) was weighed into a reaction flask, after which a nitrogen atmosphere was established using a double manifold. Anhydrous and oxygen-free tetrahydrofuran (150 mL) was added to the reaction flask under a nitrogen atmosphere. Tetra(dimethylamino)tin (29.5 g, 0.1 mol) was added under a nitrogen atmosphere, and the reaction was stirred at 60 °C for 25 h. After the reaction was complete, the solvent was removed under vacuum, and n-hexane (150 mL) was added to dissolve the intermediate product, tris(dimethylamino)tin chloride, which was filtered in a glove box to remove dimethylamino tin chloride dimer;

[0050] S2. The solvent of the filtered filtrate was drawn off, and anhydrous and oxygen-free tetrahydrofuran (100 mL) was added again. An isopropyl magnesium chloride solution (2.0 M, 50 mL, solvent: tetrahydrofuran) was slowly added under a nitrogen atmosphere, and the reaction was carried out at 40 °C for 5 h. After the reaction was completed, the solvent was drawn off, and isopropyl tris(dimethylamino)tin was distilled under short-path reduced pressure (2 Torr) at 60 °C heating conditions to obtain a crude product. The crude product was distilled under reduced pressure (3 Torr) at 45 °C heating conditions to obtain a colorless solution of finished isopropyl tris(dimethylamino)tin (25.11 g, 0.082 mol) at a yield of 82 %, a metal purity of 6N, and NMR data of: 1 H NMR (400 MHz, C6D6): δ (ppm) = 1.26-1.27 (d, 6H, C(CH3)2), 1.61 (h, 1H, C(CH3)2), 2.85 (s, 18H, N(CH3)2).

[0051] Example 3

[0052] A method for preparing isopropyl tris(dimethylamino)tin, comprising the following steps:

[0053] S1. Tin dichloride (18.96 g, 0.1 mol) was weighed into a reaction bottle in a glove box, and after being taken out, a nitrogen atmosphere was established using a double-tube. Anhydrous and oxygen-free ethylene glycol dimethyl ether (150 mL) was added to the reaction bottle under a nitrogen atmosphere. Tetra(dimethylamino)tin (29.5 g, 0.1 mol) was added under a nitrogen atmosphere, and the reaction was stirred at 60 °C for 25 h. After the reaction was completed, the solvent was removed under vacuum, and n-hexane (150 mL) was added to dissolve the intermediate product tris(dimethylamino)tin chloride. The dimethylamino tin chloride dimer was removed by filtration in a glove box;

[0054] S2. The solvent of the filtered filtrate was drawn off, and anhydrous and oxygen-free tetrahydrofuran (100 mL) was added again. An isopropyl magnesium chloride solution (2.0 M, 50 mL, solvent: tetrahydrofuran) was slowly added under a nitrogen atmosphere, and the reaction was carried out at 40 °C for 5 h. After the reaction was completed, the solvent was drawn off, and isopropyl tris(dimethylamino)tin was distilled under short-path reduced pressure (2 Torr) at 60 °C heating conditions to obtain a crude product. The crude product was distilled under reduced pressure (3 Torr) at 45 °C heating conditions to obtain a colorless solution of finished isopropyl tris(dimethylamino)tin (25.11 g, 0.082 mol) at a yield of 82 %, a metal purity of 6N, and NMR data of: 1H NMR (400 MHz, C6D6): δ (ppm) = 1.26-1.27 (d, 6H, C(CH3)2), 1.61 (h, 1H, C(CH3)2), 2.85 (s, 18H, N(CH3)2).

[0055] Example 4

[0056] A method for preparing isopropyl tri(dimethylamino)tin, comprising the following steps:

[0057] S1. In a glove box, tin dibromide (27.85 g, 0.1 mol) was weighed into a reaction bottle, and after being taken out, a nitrogen atmosphere was constructed using a double-tube. Anhydrous and oxygen-free tetrahydrofuran (150 mL) was added to the reaction bottle under a nitrogen atmosphere. Tetra(dimethylamino)tin (29.5 g, 0.1 mol) was added under a nitrogen atmosphere, and the reaction was stirred at 40 °C for 40 h. After the reaction was completed, the solvent was removed under vacuum, and n-hexane (150 mL) was added to dissolve the intermediate product tri(dimethylamino)tin bromide. The dimethylamino tin bromide dimer was removed by filtration in a glove box;

[0058] S2. The solvent of the filtrate was removed by suction, and anhydrous and oxygen-free tetrahydrofuran (100 mL) was added again. Isopropyl magnesium bromide solution (2.0 M, 50 mL, solvent: tetrahydrofuran) was slowly added under a nitrogen atmosphere, and the reaction was carried out at 80 °C for 3 h. After the reaction was completed, the solvent was removed by suction, and isopropyl tri(dimethylamino)tin was distilled under short-path reduced pressure (2 Torr) at 60 °C heating condition to obtain a crude product. The crude product was distilled under reduced pressure (2 Torr) at 40 °C heating condition to obtain a colorless solution of the finished product isopropyl tri(dimethylamino)tin (24.87 g, 0.084 mol), with a yield of 84 %, a metal purity of 6N, and nuclear magnetic resonance data as follows: 1 H NMR (400 MHz, C6D6): δ (ppm) = 1.26-1.27 (d, 6H, C(CH3)2), 1.61 (h, 1H, C(CH3)2), 2.85 (s, 18H, N(CH3)2).

[0059] Comparative Example 1

[0060] A method for preparing isopropyl tri(dimethylamino)tin, comprising the following steps:

[0061] S1. In a glove box, tin dichloride (18.96 g, 0.1 mol) was weighed into reaction flask A and lithium dimethylamide (10.20 g, 0.2 mol) was weighed into reaction flask B. After removal, a nitrogen atmosphere was provided using double manifold. Anhydrous and oxygen-free tetrahydrofuran (150 mL) was added to reaction flask A under nitrogen atmosphere. The tetrahydrofuran solution of tin dichloride was introduced into reaction flask B at -20 ℃ and stirred at room temperature overnight. After the reaction was completed, the solvent was removed by suction and n-hexane (150 mL) was added as the reaction solvent. 2-iodopropane (8.5 g, 0.05 mol) was added at room temperature under nitrogen atmosphere and stirred at 60 ℃ for 70 h. After the reaction was completed, lithium chloride and dimethylamino tin iodide dimer were removed by filtration, the solvent was removed by suction, and a crude product was obtained. The crude product was distilled under reduced pressure (2 Torr) at 40 ℃ to obtain a colorless solution of the finished product isopropyl tris(dimethylamino)tin (10.7 g, 0.0364 mol), with a yield of 36.4 %, a metal purity of 4N, and NMR data of: 1 H NMR (400 MHz, C6D6): δ(ppm) = 1.26-1.27 (d, 6H, C(CH3)2), 1.61 (h, 1H, C(CH3)2), 2.85 (s, 18H, N(CH3)2).

[0062] Comparative Example 2

[0063] A method for preparing isopropyl tris(dimethylamino)tin, comprising the following steps:

[0064] In a glove box, tin dichloride (18.96 g, 0.1 mol) was weighed into reaction flask A and lithium dimethylamide (15.30 g, 0.3 mol) was weighed into reaction flask B. After removal, a nitrogen atmosphere was provided using double manifold. Anhydrous and oxygen-free tetrahydrofuran (150 mL) was added to reaction flask A under nitrogen atmosphere. The tetrahydrofuran solution of tin dichloride was introduced into reaction flask B at -20 ℃ and stirred at 55 ℃ for 60 h. After filtration, 2-iodopropane (17.00 g, 0.1 mol) was added under nitrogen atmosphere and stirred at 60 ℃ for 5 h. After the reaction was completed, the solvent was removed by suction, n-hexane was added, and the filtrate was filtered in a glove box. The filtrate was removed by suction to obtain a crude product. The crude product was distilled under reduced pressure (2 Torr) at 40 ℃ to obtain a colorless solution of the finished product isopropyl tris(dimethylamino)tin (14.7 g, 0.05 mol), with a yield of 50 %, a metal purity of 4N, and NMR data of: 1H NMR (400MHz, C6D6): δ (ppm) = 1.26-1.27 (d, 6H, C(CH3)2), 1.61 (h, 1H, C(CH3)2), 2.85(s, 18H, N(CH3)2).

[0065] Comparative Example 1-2 is a conventional preparation method reported in the prior art, which can generate the target product isopropyl tris(dimethylamino) tin, but uses iodine-containing compounds, and the yield is only 36.4%, 50%, and the metal purity is only 4N.

[0066] Comparative Example 3

[0067] In the glove box, tin tetrachloride (26.05 g, 0.1 mol) was weighed into reaction bottle A, and after being taken out, a double-tube was used to provide a nitrogen atmosphere. Under the nitrogen atmosphere, anhydrous and oxygen-free n-hexane (200 mL) was added to reaction bottle A. Under the nitrogen atmosphere, isopropyl magnesium chloride solution (2.0 M, 50 mL, solvent: tetrahydrofuran) was slowly added at -78 °C, and the cold bath was reacted for 2 h, and then the cold bath was removed and reacted at room temperature for 6 h, and heated at 60 °C for 2 h. In the glove box, lithium dimethylamide (15.3 g, 0.3 mol) was weighed into reaction bottle B, and after being taken out, a double-tube was used to provide a nitrogen atmosphere. Under the nitrogen atmosphere, anhydrous and oxygen-free n-hexane (300 mL) was added to reaction bottle B and stirred uniformly. The mixture in reaction bottle B was transferred to reaction bottle A under the nitrogen atmosphere at -20 °C, and after being stirred for 2 h with a cold bath, the cold bath was removed and stirring was continued at room temperature for 10 h. After the reaction was completed, the solvent was dried, n-hexane (200 mL) was added and shaken uniformly, and the filtrate was obtained by filtering in the glove box. After the filtrate was dried, about 15 g of liquid product was obtained. The liquid product was characterized by nuclear magnetic resonance hydrogen spectrum, and the results confirmed that it was tetra(dimethylamino) tin, and the nuclear magnetic data was: 1 H NMR (400 MHz, C6D6): δ (ppm) = 2.82 (s, 24H, N(CH3)2).

[0068] In Comparative Example 3, isopropyl trichloride tin was first prepared by reacting tin tetrachloride with isopropyl magnesium chloride, and then the amino reaction was carried out with lithium dimethylamide, and the final product was confirmed by nuclear magnetic resonance to be only tetra(dimethylamino) tin, and the target product isopropyl tris(dimethylamino) tin was not generated.

[0069] Comparative Example 4

[0070] In a glove box, lithium dimethylamide (15.3 g, 0.3 mol) was weighed into reaction flask A, and after being taken out, a nitrogen atmosphere was provided by double-tube, and anhydrous and oxygen-free n-hexane (350 mL) was added to reaction flask A under the atmosphere. In a glove box, tin tetrachloride (26.05 g, 0.1 mol) was weighed into reaction flask B, and after being taken out, a nitrogen atmosphere was provided by double-tube, and anhydrous and oxygen-free n-hexane (100 mL) was added to reaction flask B and stirred until uniform. Under a nitrogen atmosphere at -78 ℃, the mixture in reaction flask B was slowly added dropwise into reaction flask A, the cold bath was kept and stirring was continued for 2 h, and then the cold bath was removed and the reaction was stirred at room temperature for 10 h. Then under a nitrogen atmosphere at -20 ℃, isopropyl magnesium chloride solution (2.0 M, 50 mL, solvent: tetrahydrofuran) was slowly added to the system, and the reaction was carried out at room temperature for 1 h, and then the temperature was raised to 60 ℃ and the reaction was continued for 5 h. After the reaction was completed, the solvent was removed by suction, n-hexane (200 mL) was added to the residue and shaken until uniform, and the filtrate was obtained by filtering in a glove box. The filtrate was dried by suction to obtain about 5 g of liquid product, and the yield was 17% according to the molecular weight of the product.

[0071] Example 4 aims to introduce isopropyl ligand by first constructing a stable tin tris(dimethylamino) chloride intermediate, and then carrying out isopropylation reaction with isopropyl magnesium chloride. However, nuclear magnetic resonance characterization of the product shows that the main peak position of the nuclear magnetic resonance deviates from that of the target product isopropyl tris(dimethylamino) tin, and two groups of isopropyl characteristic peaks with different areas appear, indicating that the obtained product is a mixture. This may be because the activity of tin tetrachloride is too high, and the ligand exchange is out of control when reacting with lithium dimethylamide, generating a mixture of various amino tin chloride intermediates, and the subsequent isopropylation reaction further aggravates the complexity of the product.

[0072] Example 5

[0073] In a glove box, tin tetrakis(dimethylamino) (29.5 g, 0.1 mol) was weighed into a reaction flask, and after being taken out, a nitrogen atmosphere was provided by double-tube, and anhydrous and oxygen-free n-hexane (150 mL) was added to the reaction flask. Then under a nitrogen atmosphere, tin tetrachloride (26.05 g, 0.1 mol) was added to the system, and only a small amount of dropwise addition immediately generated a precipitate and was accompanied by obvious heat release; subsequently, the reaction flask was placed in a -78 ℃ cold bath and continued to be added dropwise, and a large amount of precipitate was still rapidly generated, and the reaction progress was completely uncontrollable.

[0074] This is because tin tetrachloride has strong acidity and high reactivity, and immediately reacts violently after contacting with tin tetrakis(dimethylamino), rapidly generating a large amount of precipitate and being accompanied by obvious heat release, even under the condition of -78 ℃, the reaction progress cannot be controlled, and the intermediates cannot be synthesized directionally, which does not follow the rule of ligand exchange one by one.

[0075] Comparative Example 6

[0076] Tetrakis(dimethylamino)tin (29.5 g, 0.1 mol) was weighed into a reaction flask and a nitrogen atmosphere was established via a double manifold. Under a nitrogen atmosphere, anhydrous and oxygen-free n-hexane (300 mL) was added to the reaction flask, followed by the slow addition of 2-bromopropane (12.3 g, 0.1 mol). No exotherm was observed during the entire addition and no physical or chemical changes were observed in the system. It was confirmed that tetrakis(dimethylamino)tin did not react with 2-bromopropane. This is likely because 2-bromopropane is not sufficiently reactive to break the stable Sn-N bond in tetrakis(dimethylamino)tin and replace the ligands.

[0077] Comparative Example 7

[0078] Tetrakis(dimethylamino)tin (29.5 g, 0.1 mol) was weighed into a reaction flask and a nitrogen atmosphere was established via a double manifold. Under a nitrogen atmosphere, anhydrous and oxygen-free n-hexane (300 mL) was added to the reaction flask, followed by the slow addition of isopropylmagnesium chloride solution (2.0 M, 50 mL, solvent: tetrahydrofuran). A large amount of solid was rapidly formed upon the start of the addition, and the reaction was completely out of control due to the strong exotherm. This is likely because isopropylmagnesium chloride is too reactive and reacts non-selectively with tetrakis(dimethylamino)tin, which can break the Sn-N bond and trigger a polymerization or precipitation reaction, and cannot achieve directional ligand exchange.

[0079] Comparative Examples 6 and 7 were intended to simplify the preparation method by directly reacting tetrakis(dimethylamino)tin with isopropylating reagents (2-bromopropane, isopropylmagnesium chloride) to achieve ligand exchange and prepare the target product in one step, but both experiments failed.

[0080] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. Those skilled in the art should understand that on the basis of the above description, other different forms of changes or variations can also be made. Here, it is not necessary and also impossible to exhaust all the embodiments. Any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the claims of the present application.

Claims

1. A process for the preparation of isopropyl tris(dimethylamino) tin, characterized in that, The method comprises the following steps: S1. Reacting tin dihalide with tin tetra(dimethylamino) in an organic solvent under an inert gas atmosphere to obtain a mixed solution containing tin tris(dimethylamino) halide and dimethylamino tin halide dimer, removing the dimethylamino tin halide dimer by separation treatment to obtain tin tris(dimethylamino) halide; the tin dihalide is tin dichloride and / or tin dibromide; S2. Reacting the tin tris(dimethylamino) halide with an isopropylating agent in an organic solvent under an inert gas atmosphere, and distilling and purifying the obtained reaction product to obtain the isopropyl tin tris(dimethylamino); the isopropylating agent is selected from one or more of isopropylmagnesium chloride, isopropylmagnesium bromide and isopropyl lithium.

2. The production method according to claim 1, characterized by, In S1, the inert gas is nitrogen or argon; in S2, the inert gas is nitrogen or argon.

3. The preparation method according to claim 1, characterized in that, In S1, the molar ratio of the tin dihalide to the tin tetra(dimethylamino) is (0.8-1.2):

1.

4. The production method according to claim 1, characterized by, In S1, the organic solvent is selected from one or more of tetrahydrofuran, ethylene glycol dimethyl ether and diethyl ether.

5. The preparation method according to claim 1, characterized in that, In S1, the reaction temperature is 25-85 ℃, and the reaction time is 10-50 h.

6. The method of claim 1, wherein, In S1, the specific separation treatment is: first removing the organic solvent in the mixed solution, then adding n-hexane to dissolve the tin tris(dimethylamino) halide, and then filtering to remove the dimethylamino tin halide dimer.

7. The preparation method according to claim 1, characterized in that, In S2, the molar ratio of the tin tris(dimethylamino) halide to the isopropylating agent is (0.8-1.2):

1.

8. The method of claim 1, wherein, In S2, the organic solvent is selected from one or more of tetrahydrofuran, ethylene glycol dimethyl ether and diethyl ether.

9. The method of claim 1, wherein, In S2, the reaction temperature is 40-80 ℃, and the reaction time is 3-5 h.

10. The method of claim 1, wherein, In S2, the distillation and purification is performed by two-step vacuum distillation; the temperature and the vacuum degree of the two-step vacuum distillation are 30-80 ℃ and 1-5 Torr, respectively.

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