Preparation method of diethylaminotrialkoxysilane

Abstract

The present invention relates to the technical field of synthesizing silane compounds containing nitrogen atoms, and more specifically, to a method for synthesizing diethylaminotrialkoxysilane. This method utilizes a stepwise initiation process using a non-protonic nucleophilic solvent and a non-polar solvent, thereby improving the synthesis yield of diethylaminotrialkoxysilane and alleviating technical difficulties encountered during salt treatment, such as residue filtration and the introduction of an acid-binding agent.

Description

Technical Field

[0001] The present invention relates to the technical field of synthesis of silane compounds containing N atoms, and more particularly to a method for synthesizing diethylaminotrialkoxysilane. Background Art

[0002] Diethylaminotrialkoxysilane, also known as diethylaminotrialkoxysilane, N-ethyl-N-trialkoxysilylethylamine or N,N-diethyl-trialkoxysilylamine, has the following structural formula:

[0003]

[0004] Wherein, R can be methyl, ethyl, propyl, isopropyl or n-butyl, isobutyl, tert-butyl, cyclopentyl, cyclohexyl or phenyl, and R can optionally be methyl or ethyl.

[0005] Diethylaminotrialkoxysilane can be used as an external electron donor in olefin polymerization and is an important raw material for olefin polymerization. Related research has found that using diethylaminotrialkoxysilane as an external electron donor in propylene polymerization can improve the hydrogen sensitivity of the polymerization reaction and produce polypropylene with high isotacticity and high melt index ("catalysts2022,12,864"). As an external electron donor with excellent performance, it is still necessary to develop a method for synthesizing diethylaminotrialkoxysilane with simple process, low cost and high yield. Summary of the Invention

[0006] Based on this, the inventors used a step-by-step initiation process using aprotic nucleophilic solvents and non-polar solvents, which not only improved the synthesis efficiency and yield of diethylaminotrialkoxysilane; but also this preparation method can improve the technical difficulties such as residue filtration during salt treatment and the introduction of acid binding agents.

[0007] To this end, the embodiments of the present invention disclose at least the following technical solutions:

[0008] The embodiment discloses a method for preparing diethylaminotrialkoxysilane, which comprises: preparing diethylaminomagnesium halide in a nitrogen atmosphere and an aprotic nucleophilic solvent; and reacting the diethylaminomagnesium halide with orthosilicate in a non-polar solvent.

[0009] In some embodiments, the diethylaminotrialkoxysilane is selected from at least one of diethylaminotrimethoxysilane, diethylaminotriethoxysilane, diethylaminotri-n-propoxysilane, diethylaminotriisopropoxysilane, diethylaminotri-n-butoxysilane, diethylaminotriisobutoxysilane, diethylaminotri-tert-butoxysilane, diethylaminotripentoxysilane, diethylaminotricyclopentoxysilane, diethylaminotricyclohexyloxysilane, and diethylaminotriphenoxysilane.

[0010] In some embodiments, the step of preparing diethylamino magnesium halide comprises: reacting a halogenated hydrocarbon and magnesium in the aprotic nucleophilic solvent via iodine initiation to obtain an alkyl magnesium halide; and reacting the alkyl magnesium halide with diethylamine to obtain the diethylamino magnesium halide.

[0011] In some embodiments, the aprotic nucleophilic solvent is a mixture of one or more polar solvents such as tetrahydrofuran and diethyl ether.

[0012] In some embodiments, the halogenated hydrocarbon is a linear, non-linear, or cyclic hydrocarbon containing halogen and having a carbon number greater than or equal to 1. The halogen is selected from chlorine, bromine, or iodine.

[0013] In some embodiments, the alkyl magnesium halide is a compound formed by the halogenated hydrocarbon and the magnesium. The alkyl magnesium halide is selected from methyl magnesium chloride, methyl magnesium bromide, methyl magnesium iodide, ethyl magnesium chloride, ethyl magnesium bromide, ethyl magnesium iodide, n-propyl magnesium chloride, n-propyl magnesium bromide, n-propyl magnesium iodide, isopropyl magnesium chloride, isopropyl magnesium bromide, isopropyl magnesium iodide, n-butyl magnesium chloride, n-butyl magnesium bromide, n-butyl magnesium iodide, isobutyl magnesium chloride, isobutyl magnesium bromide, isobutyl magnesium iodide, tert-butyl magnesium chloride, tert-butyl magnesium bromide, tert-butyl magnesium iodide, cyclopentyl magnesium chloride, cyclopentyl magnesium bromide ... Pentylmagnesium chloride, cyclopentylmagnesium bromide, cyclopentylmagnesium iodide, cyclohexylmagnesium chloride, cyclohexylmagnesium bromide, cyclohexylmagnesium iodide, phenylmagnesium chloride, phenylmagnesium bromide, phenylmagnesium iodide, optionally at least one of methylmagnesium chloride, methylmagnesium bromide, n-propylmagnesium chloride, n-propylmagnesium bromide, isopropylmagnesium chloride, isopropylmagnesium bromide, isobutylmagnesium chloride, isobutylmagnesium bromide, cyclopentylmagnesium chloride, cyclopentylmagnesium bromide, cyclohexylmagnesium chloride and cyclohexylmagnesium bromide.

[0014] In some embodiments, the molar ratio of the halogenated hydrocarbon to the magnesium is 1:(0.8-1.3), optionally 1:(1.0-1.1).

[0015] In some embodiments, the molar ratio of the alkyl magnesium halide to the diethylamine is 1:(0.9-1.5), optionally 1:1.0-1.3.

[0016] In some embodiments, the orthosilicate is selected from one or more of methyl orthosilicate, ethyl orthosilicate, n-propyl orthosilicate, isopropyl orthosilicate, n-butyl orthosilicate, isobutyl orthosilicate, tert-butyl orthosilicate, tetracyclopentyl orthosilicate, tetracyclohexyl orthosilicate, and tetraphenoxysilane, optionally methyl orthosilicate and ethyl orthosilicate.

[0017] In some embodiments, the molar ratio of the orthosilicate to the diethylamine is (0.9-1.5):(0.6-1.0), optionally (1.0-1.3):(0.7-0.9).

[0018] In some embodiments, the non-polar solvent is selected from cyclohexane and / or petroleum ether.

[0019] The preparation method of diethylaminotrialkoxysilane provided in the embodiment avoids the use of corrosive raw materials such as chlorosilane to produce corrosive hydrogen chloride, has the advantages of simple process, no need to introduce acid binding agents, low cost and high yield (up to at least 90%), and has good economic value in industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 The schematic diagram of the process for preparing diethylaminotrialkoxysilane provided in the examples. Figure 1 A is a schematic diagram of the preparation process of diethylamino magnesium halide. Figure 1 B is a schematic flow diagram of the reaction of diethylamino magnesium halide and orthosilicate (Si(OR2)4) in a non-polar solvent. DETAILED DESCRIPTION

[0021] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the following examples. It should be understood that the specific examples described herein are merely illustrative of the present invention and are not intended to limit the present invention. Reagents not described in detail herein are all conventional reagents and are commercially available; methods not specifically described in detail are all conventional experimental methods and are known in the art.

[0022] The embodiment discloses a method for preparing diethylaminotrialkoxysilane, which comprises: preparing diethylaminomagnesium halide in a nitrogen atmosphere and an aprotic nucleophilic solvent; and reacting the diethylaminomagnesium halide with orthosilicate in a non-polar solvent.

[0023] Figure 1 A discloses a schematic flow diagram for preparing diethylamino magnesium halide. The steps include: reacting a halogenated hydrocarbon (R1-X) and magnesium in an aprotic nucleophilic solvent via iodine initiation to obtain an alkyl magnesium halide (R1-MgX); and reacting the alkyl magnesium halide with diethylamine to obtain the diethylamino magnesium halide. R1 is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopentyl, cyclohexyl, or phenyl. X is a halogen.

[0024] Figure 1 B discloses the step of reacting the diethylamino magnesium halide with orthosilicate (Si(OR2)4) in a non-polar solvent, wherein R2 is selected from methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclopentyl, cyclohexyl or phenyl.

[0025] Example 1

[0026] Example 1 discloses a method for preparing diethylaminotrimethoxysilane. Specifically, it includes:

[0027] 1) Preparation of diethylamino magnesium chloride

[0028] Under nitrogen protection, 250 ml of an equal volume mixed solvent of tetrahydrofuran and ether, 0.2 mol of 2-chloropropane and 1.1 mol of magnesium particles were added to a dry reaction flask respectively. The temperature was raised to reflux, and 0.001 mol of iodine was added to initiate the reaction. After the reaction stabilized, 0.8 mol of 2-chloropropane was added dropwise. After the addition was completed, the reaction temperature was controlled at 70°C and stirred for 8 hours to obtain a solution containing 0.95 mol of isopropylmagnesium chloride.

[0029] 1.08 mol of diethylamine was slowly added dropwise to a solution containing 0.95 mol of isopropylmagnesium chloride, and the reaction temperature was controlled at 70° C. and stirred for 8 hours to obtain a solution containing 0.892 mol of diethylaminomagnesium chloride.

[0030] 2) Preparation of diethylaminotrimethoxysilane

[0031] To a reaction flask containing a cyclohexane solution of 0.892 mol of methyl orthosilicate, a diethylamino magnesium halide solution containing 0.892 mol was slowly added dropwise via a titrator, and the reaction was stirred for 8 h. The reaction temperature was controlled not to exceed 70° C. by the dropping rate. The reaction was stopped when the methyl orthosilicate content in the reaction solution was less than 0.1% by gas GC detection. The reaction solution was filtered and distilled to obtain 0.853 mol of a colorless, transparent product, diethylaminotrimethoxysilane, with a GC purity of 99.1% and a yield (as the ratio of the product molar ratio to the silicate molar ratio, the same below) of 95.6%. The hydrogen nuclear magnetic spectrum data of diethylaminotrimethoxysilane were: 1H-NMR (400 MHz, CDCl3, δ): 1.02 ppm (6H, NCH2CH3), 2.59 ppm (4H, NCH2CH3), 3.55 ppm (9H, OCH3).

[0032] Example 2

[0033] Example 2 discloses a method for preparing diethylaminotrimethoxysilane. Specifically, it includes:

[0034] 1) Preparation of diethylamino magnesium chloride

[0035] Under nitrogen protection, 250 ml of an equal volume mixed solvent of tetrahydrofuran and ether, 0.2 mol of chlorocyclopentane, and 1.1 mol of magnesium particles were added to a dry reaction flask respectively. The temperature was raised to reflux, and 0.001 mol of iodine was added to initiate the reaction. After the reaction stabilized, 0.8 mol of chlorocyclopentane was added dropwise. After the addition was completed, the reaction temperature was controlled at 70°C and stirred for 8 hours to obtain a solution containing 0.915 mol of cyclopentylmagnesium chloride.

[0036] 1.01 mol of diethylamine was slowly added dropwise to a solution containing 0.915 mol of cyclopentylmagnesium chloride, and the reaction temperature was controlled at 70° C. and stirred for 8 h to obtain a solution containing 0.882 mol of diethylaminomagnesium chloride.

[0037] 2) Preparation of diethylaminotrimethoxysilane

[0038] In the second step, 0.882 mol of diethylamino magnesium halide solution prepared in the first step was slowly added dropwise to a reaction flask containing 0.882 mol of cyclohexane solution of methyl orthosilicate through a titration apparatus, and the reaction was stirred for 8 hours. The reaction temperature was controlled not to exceed 70° C. by the dropwise addition rate. The reaction was stopped when the methyl orthosilicate content in the reaction solution was less than 0.1% by gas GC detection. The reaction solution was filtered and distilled to obtain 0.843 mol of colorless and transparent product diethylaminotrimethoxysilane with a GC purity of 99.0% and a yield of 95.6%. The hydrogen nuclear magnetic spectrum data of diethylaminotrimethoxysilane were: 1H-NMR (400 MHz, CDCl3, δ): 1.02 ppm (6H, NCH2CH3), 2.59 ppm (4H, NCH2CH3), 3.55 ppm (9H, OCH3).

[0039] Example 3

[0040] Example 3 discloses a method for preparing diethylaminotriethoxysilane, which specifically includes:

[0041] 1) Preparation of diethylamino magnesium chloride

[0042] The same steps as in Example 1 were used to prepare diethylamino magnesium chloride.

[0043] 2) Preparation of diethylaminotriethoxysilane

[0044] To a solution containing 0.895 mol of ethyl orthosilicate and petroleum ether, a solution containing 0.895 mol of diethylamino magnesium halide was added dropwise, and the reaction was stirred for 8 h. The reaction temperature was controlled not to exceed 70° C. by the dropping rate. The reaction was stopped when the ethyl orthosilicate content in the reaction solution was less than 0.1% by gas GC detection. The reaction solution was filtered and distilled to obtain 0.843 mol of colorless, transparent product diethylaminotriethoxysilane with GC purity of 99.0% and a yield of 94.2%. The hydrogen nuclear magnetic spectrum data of diethylaminotriethoxysilane were: 1H-NMR (400 MHz, CDCl3, δ): 1.02 ppm (6H, NCH2CH3), 2.60 ppm (4H, NCH2CH3), 1.21 ppm (6H, OCH2CH3), 3.83 ppm (9H, OCH2CH3).

[0045] Example 4

[0046] Example 4 discloses a method for preparing diethylaminotriethoxysilane. Specifically, it includes:

[0047] 1) Preparation of diethylamino magnesium chloride

[0048] Under nitrogen protection, 250 ml of tetrahydrofuran, 0.2 mol of isobutyl chloride, and 1.1 mol of magnesium particles were added to a dry reaction flask respectively. The temperature was raised to reflux, and 0.001 mol of iodine was added to initiate the reaction. After the reaction stabilized, 0.8 mol of isobutyl chloride was added dropwise. After the addition was completed, the reaction temperature was controlled at 70 ° C and stirred for 8 hours to obtain a solution containing 0.937 mol of isobutylmagnesium chloride.

[0049] 1.03 mol of diethylamine was slowly added dropwise to a solution containing 0.937 mol of isobutylmagnesium chloride, and the reaction temperature was controlled at 70° C. and stirred for 8 h to obtain a solution containing 0.852 mol of diethylaminomagnesium chloride.

[0050] 2) Preparation of diethylaminotriethoxysilane

[0051] To a petroleum ether solution containing 0.852 mol of ethyl orthosilicate was slowly added dropwise a solution containing 0.852 mol of diethylamino magnesium halide, and the reaction was stirred for 8 h. The reaction temperature was controlled by the dropwise addition rate so as not to exceed 70° C. The reaction was stopped when the ethyl orthosilicate content in the reaction solution was less than 0.1% as determined by gas GC. The reaction solution was filtered and distilled to obtain 0.788 mol of a colorless, transparent product, diethylaminotriethoxysilane, with a GC purity of 99.2% and a yield of 92.5%. The hydrogen nuclear magnetic spectrum data of diethylaminotriethoxysilane were: 1H-NMR (400 MHz, CDCl3, δ): 1.02 ppm (6H, NCH2CH3), 2.60 ppm (4H, NCH2CH3), 1.21 ppm (6H, OCH2CH3), 3.83 ppm (9H, OCH2CH3).

[0052] Example 5

[0053] Example 5 discloses a method for preparing diethylaminotriethoxysilane. Specifically, it includes:

[0054] 1) Preparation of diethylamino magnesium chloride

[0055] Under nitrogen protection, 250 ml of an equal volume mixed solvent of tetrahydrofuran and ether, 0.2 mol of chlorocyclohexane, and 1.1 mol of magnesium particles were added to a dry reaction flask respectively. The temperature was raised to reflux, and 0.001 mol of iodine was added to initiate the reaction. After the reaction stabilized, 0.8 mol of chlorocyclohexane was added dropwise. After the addition was completed, the reaction temperature was controlled at 70°C and stirred for 8 hours to obtain a cyclohexane magnesium chloride solution containing 0.95 mol.

[0056] Slowly add 1.05 mol of diethylamine dropwise to a 0.95 mol cyclohexane magnesium chloride solution, control the reaction temperature at 70°C and stir for 8 hours to obtain a 0.851 mol diethylamino cyclohexyl magnesium chloride solution;

[0057] 2) Preparation of diethylaminotriethoxysilane

[0058] To a petroleum ether solution containing 0.851 mol of ethyl orthosilicate, a diethylamino magnesium halide solution containing 0.851 mol was slowly added dropwise, and the reaction was stirred for 8 h. The reaction temperature was controlled not to exceed 70° C. by the dropping rate. The reaction was stopped when the ethyl orthosilicate content in the reaction solution was less than 0.1% by gas GC detection. The reaction solution was filtered and distilled to obtain 0.803 mol of colorless, transparent product, diethylaminotriethoxysilane, with a GC purity of 99.2% and a yield of 94.4%. The hydrogen nuclear magnetic spectrum data of diethylaminotriethoxysilane were: 1H-NMR (400 MHz, CDCl3, δ): 1.02 ppm (6H, NCH2CH3), 2.60 ppm (4H, NCH2CH3), 1.21 ppm (6H, OCH2CH3), 3.83 ppm (9H, OCH2CH3).

[0059] Example 6

[0060] Example 6 discloses a method for preparing diethylaminotri-n-propoxysilane. Specifically, it includes:

[0061] 1) Preparation of diethylamino magnesium chloride

[0062] Under nitrogen protection, 250 ml of tetrahydrofuran, 0.2 mol of isobutyl chloride, and 1.1 mol of magnesium particles were added to a dry reaction flask respectively. The temperature was raised to reflux, and 0.001 mol of iodine was added to initiate the reaction. After the reaction stabilized, 0.8 mol of isobutyl chloride was added dropwise. After the addition was completed, the reaction temperature was controlled at 70 ° C and stirred for 8 hours to obtain a solution containing 0.931 mol of isobutyl magnesium chloride.

[0063] Slowly add 1.00 mol of diethylamine dropwise to a solution containing 0.931 mol of isobutylmagnesium chloride, control the reaction temperature at 70°C, and stir the reaction for 8 hours to obtain a solution containing 0.861 mol of diethylaminomagnesium chloride;

[0064] 2) Preparation of diethylaminotri-n-propoxysilane

[0065] To a petroleum ether solution containing 0.861 mol of propyl orthosilicate, a solution containing 0.861 mol of diethylamino magnesium halide was slowly added dropwise, and the reaction was stirred for 8 h. The reaction temperature was controlled not to exceed 70° C. by the dropping rate. The reaction was stopped when the content of propyl orthosilicate in the reaction solution was less than 0.1% by gas GC detection. The reaction solution was filtered and distilled to obtain 0.783 mol of colorless, transparent product, diethylaminotri-n-propoxysilane, with a GC purity of 98.9% and a yield of 90.9%. The hydrogen nuclear magnetic spectrum data of diethylaminotri-n-propoxysilane were: 1H-NMR (400 MHz, CDCl3, δ): 1.02 ppm (6H, NCH2CH3), 2.60 ppm (4H, NCH2CH3), 0.91 ppm (9H, OCH2CH2CH3), 1.51 ppm (6H, OCH2CH2CH3), 3.79 ppm (6H, OCH2CH2CH3).

[0066] Example 7

[0067] Example 7 discloses a method for preparing diethylaminotriisopropoxysilane, which specifically includes:

[0068] 1) Preparation of diethylamino magnesium chloride

[0069] Diethylamino magnesium chloride was prepared by the method of Reference Example 6.

[0070] 2) Preparation of diethylaminotriisopropoxysilane

[0071] To a petroleum ether solution containing 0.876 mol of isopropyl orthosilicate, a solution containing 0.876 mol of diethylamino magnesium halide was slowly added dropwise, and the reaction was stirred for 8 h. The reaction temperature was controlled not to exceed 70° C. by the dropping speed. The reaction was stopped when the isopropyl orthosilicate content in the reaction solution was less than 0.1% by gas GC detection. The reaction solution was filtered and distilled to obtain 0.790 mol of colorless and transparent product diethylaminoisopropoxysilane with GC purity of 98.9% and a yield of 90.2%. The hydrogen nuclear magnetic spectrum data of diethylaminoisopropoxysilane were: 1H-NMR (400 MHz, CDCl3, δ): 1.02 ppm (6H, NCH2CH3), 2.60 ppm (4H, NCH2CH3), 1.25 ppm (18H, OCH(CH3)2), 3.57 ppm (3H, OCH(CH3)2).

[0072] Example 8

[0073] Example 8 discloses a method for preparing diethylaminotricyclohexyloxysilane. Specifically, it includes:

[0074] 1) Preparation of diethylamino magnesium chloride

[0075] Diethylamino magnesium chloride was prepared by the method of Reference Example 6.

[0076] 2) Preparation of diethylaminotricyclohexyloxysilane

[0077] To a petroleum ether solution containing 0.877 mol of tetracyclohexyl orthosilicate was slowly added dropwise a solution of diethylamino magnesium halide. The mixture was stirred for 8 hours. The reaction temperature was controlled to not exceed 70°C by the addition rate. The reaction was terminated when the tetracyclohexyl orthosilicate content in the reaction solution fell below 0.1% as determined by gas chromatography (GC). The reaction solution was filtered and distilled to obtain 0.789 mol of a colorless, transparent product, diethylaminotricyclohexyloxysilane, with a GC purity of 98.1% and a yield of 90.0%. H NMR data for diethylaminotricyclohexyloxysilane: 1H-NMR (400 MHz, CDCl3, δ): 1.02 ppm (6H, NCH2CH3), 2.60 ppm (4H, NCH2CH3), 1.43-1.72 ppm (30H, CH2), 3.17 ppm (3H, OCH3). Comparative Example 1: Grignard reagent catalyzed reaction of orthosilicate and Synthesis of diethylamine to prepare diethylaminotriethoxysilane

[0078] CN1675255A is a method for synthesizing diethylaminotriethoxysilane in Comparative Example 1 as follows:

[0079] First, 100mL toluene, 10mL tetrahydrofuran, 0.2mol diethylamine are introduced into a four-necked flask equipped with a magnetic sealed stirrer and a dropping funnel, and mixed and stirred. On the other hand, 0.22mol Grignard reagent is added to the dropping funnel, and after the addition is completed, it is stirred at 60°C for 1 hour. Then, 0.2mol tetraethoxysilane, which has been previously introduced into the dropping funnel, is added dropwise to the flask over 15 minutes. After the addition is completed, the reaction is carried out at 60°C for 2 hours. At this time, ethoxymagnesium chloride solid is precipitated in the flask. Under a nitrogen atmosphere, the reaction solution in the flask is all transferred to a container equipped with a G4 glass filter and filtered under pressure with low-pressure nitrogen (0.01MPa). Further, the residue (ethoxymagnesium chloride) is washed with toluene until no target is confirmed in the filtrate, and repeated washing and filtering are performed. The mixture of the filtrate and the residue washing solution was concentrated under reduced pressure, and the solvent components such as toluene were distilled off. Then, the mixture was purified by distillation to recover 0.102 mol of a colorless transparent liquid product with a GC purity of 98.0% and a yield of 51.0%.

[0080] Comparative Example 2

[0081] CN117624215A discloses a method for synthesizing N,N-diethyl-trialkoxysilylamines, primarily by reacting thionyl chloride with TEOS and then reacting with ethylenediamine. Although this method avoids the release of HCl by using silicon tetrachloride to prepare trialkoxysilyl chloride, the synthesis process still requires excessive diethylamine to react with HCl (to avoid HCl release), resulting in the production of a large amount of ammonium salt, increasing the subsequent salt disposal problem. Furthermore, the raw material thionyl chloride is highly toxic and easily decomposes to release irritating gases such as HCl and SO2, potentially posing a hazard to the equipment. Example 2 of CN117624215A specifically discloses: Under nitrogen protection, 76.11g (0.5mol) of methyl orthosilicate is heated to 50°C, 60.07g of thionyl chloride is added dropwise, and the mixture is kept at 54-56°C for 2h. The methyl orthosilicate content is 1.24% by gas chromatography. The mixture is kept warm for 0.5h, and unreacted thionyl chloride is removed by heating a water pump at -0.06--0.05MPa and 60°C under reduced pressure until no bubbles are left. The mixture is cooled to room temperature, and 91.43g of thionyl chloride is slowly added dropwise through a constant pressure dropping funnel. Ethylamine reacted with 46 g of n-hexane with a water content of 463 ppm in an exothermic reaction. The material temperature was controlled not to exceed 70°C by the dropwise addition rate. After addition, the material temperature was lowered to room temperature with stirring and filtered. The filtrate was distilled under atmospheric pressure to recover unreacted diethylamine and solvent n-hexane. The product was collected by heating under reduced pressure distillation at -0.08 to -0.07 MPa and 100 to 105°C to obtain 79.36 g (0.41 mol) of the product N,N-diethyl-trimethoxysilylamine with a content of 98.65% (GC), with a yield of 82.1%.

[0082] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed by the present invention should be covered by the scope of protection of the present invention.

Claims

1. A method for preparing diethylaminotrialkoxysilane, comprising: Under nitrogen atmosphere, a halogenated hydrocarbon and magnesium are reacted in tetrahydrofuran or a mixed solution of tetrahydrofuran and diethyl ether in equal volumes with iodine to obtain an alkyl magnesium halide; reacting the alkyl magnesium halide with diethylamine to obtain diethylamino magnesium halide; and reacting the diethylamino magnesium halide with orthosilicate in a reaction system using cyclohexane or petroleum ether as a solvent; wherein the halogenated hydrocarbon is selected from 2-chloropropane, chlorocyclopentane, chloroisobutane or chlorocyclohexane; Wherein, the alkyl magnesium halide is selected from isopropyl magnesium chloride, isobutyl magnesium chloride, cyclopentyl magnesium chloride or cyclohexyl magnesium chloride; Wherein, the molar ratio of the halogenated hydrocarbon to the magnesium is 1:(0.8-1.3); Wherein, the molar ratio of the alkyl magnesium halide to the diethylamine is 1:(0.9-1.5); Wherein, the orthosilicate is selected from one of methyl orthosilicate, ethyl orthosilicate, orthopropyl orthosilicate, isopropyl orthosilicate, and tetracyclohexyl orthosilicate; Wherein, the molar ratio of the orthosilicate to the diethylamine is (0.9-1.5):(0.6-1.0); Wherein, the diethylaminotrialkoxysilane is selected from diethylaminotrimethoxysilane, diethylaminotriethoxysilane, diethylaminotri-n-propoxysilane, diethylaminotriisopropoxysilane or diethylaminotricyclohexyloxysilane.

2. The preparation method according to claim 1, wherein the molar ratio of the halogenated hydrocarbon to the magnesium is 1:(1.0-1.1).

3. preparation method according to claim 1, the mol ratio of described alkyl magnesium halide and described diethylamine is 1:1.0~1.

3.

4. The preparation method according to claim 1, wherein the molar ratio of the orthosilicate to the diethylamine is (1.0-1.3):(0.7-0.9).

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