A method for preparing isocyanate group-containing alkoxysilane

Abstract

The present invention discloses a preparation method of isocyanate group alkoxysilane, which belongs to the field of synthesis of silane coupling agents. The preparation method comprises the following steps: using amino alkoxysilane and phosgene as reaction raw materials, and directly synthesizing isocyanate group alkoxysilane in one step without using an acid-binding agent during the phosgenation process. The present invention solves the problem of low yield in the existing method for preparing isocyanate group alkoxysilane, and the excessive phosgene and solvent can be recycled, improving the utilization efficiency of phosgene.

Description

Technical Field

[0001] The present invention belongs to the technical field of silane coupling agents, and particularly relates to an isocyanate group alkoxysilane and a preparation method thereof. Background Art

[0002] Silane coupling agents are an important part of adhesive materials, and isocyanate silane coupling agents are a special type of silane coupling agent that can adhere to various common and uncommon substrates and have very excellent effects in surface treatment of organic materials and inorganic metals, especially in glass fiber-reinforced composites, treatment of inorganic powder fillers, and tackifiers for coatings and inks. At the same time, isocyanate silane coupling agents have very good thermal stability, chemical stability, and anti-ultraviolet stability, and are widely used in polymer material fields such as adhesives and resin structure improvement of polyurethane materials. Among them, isocyanate group alkoxysilane is the most important isocyanate-containing silane coupling agent.

[0003] Currently, the chemical methods for synthesizing isocyanate-containing silane coupling agents are known;

[0004] For example, the reaction of haloalkyl alkoxysilane with metal cyanate gives isocyanate (CN110437273A, DE3524215A). However, raw materials such as sodium isocyanate or potassium salt are highly toxic raw materials and are prone to generating a large amount of waste salts, so it is not conducive to research or large-scale production;

[0005] Using amino silane and carbonate as raw materials, reacting under the action of a basic catalyst to generate a mixture of silicon-based organic carbamates, and after neutralizing with a neutralizing reagent, subjecting the mixed reaction solution to vacuum distillation cracking to obtain a silane containing an isocyanate group (CN1631893A, US5886205A). However, the disadvantages of this method are that the reaction steps are cumbersome, there are many by-products, and high-temperature cracking has high requirements for equipment;

[0006] Preparing isocyanate compounds by reacting phosgene with ammonia in an inert solvent (CN104203910A, DE3544601A), the process route is simple and the theoretical yield is high, but the reaction by-product hydrogen chloride is prone to undergo a substitution reaction with the silicon-oxygen bond to generate chloro impurities and alcohols. The chloro impurities will reduce the storage stability of the product, and the alcohols will react with the isocyanate to form carbamate, resulting in a low overall yield. Tertiary amine-based acid-binding agents can be used to neutralize the by-product hydrochloric acid in the phosgenation reaction to improve the yield of isocyanate (US4654428A, CN 104334565A), but tertiary amines are expensive and will generate a large amount of tertiary amine hydrochloride, which has small particle size and is not easy to separate and is hardly soluble in general inert organic solvents. Decantation and centrifugation will increase equipment investment and will have a serious environmental impact on the environment.

[0007] Therefore, a synthesis method suitable for isocyanate group alkoxysilanes still needs to be developed. It is necessary to control the by-products in the synthesis process, reduce the operation steps and increase the product yield. Summary of the Invention

[0008] To overcome the deficiencies of the prior art, the object of the present invention is to provide an isocyanate group alkoxysilane and a preparation method thereof. By adjusting the phosgene flux and reaction temperature, the generation of by-products in the phosgenation reaction is reduced without using an acid-binding agent, and the yield of isocyanate group alkoxysilane is increased.

[0009] To achieve the above object, the technical scheme adopted by the present invention is as follows:

[0010] An isocyanate group alkoxysilane having the general formula (I):

[0011]

[0012] Wherein, R1, R2, and R3 are the same or different, and are saturated alkyl or saturated alkoxy groups, and at least one group is a saturated alkoxy group. The carbon chain length of the alkyl or alkoxy group is C1-C6;

[0013] R4 is a branched or straight-chain alkylene or cycloalkylene or arylene or aralkyl group. The branched or straight-chain alkylene or cycloalkylene contains 1-12 carbon atoms, the arylene contains 6-10 carbon atoms, and the aralkyl group contains 7-10 carbon atoms. Preferably, it is a substituted or unsubstituted —(CH2)n—, and n is a positive integer from 1 to 6.

[0014] Its preparation method includes the following steps:

[0015] (A). Dissolve the amino alkoxysilane having the general formula (II) in an inert organic solvent and react with phosgene in a reaction device; the lower part of the reaction device is directly connected to a residual phosgene and hydrogen chloride separation device;

[0016] The structural formula of the amino alkoxysilane is:

[0017]

[0018] (B). Remove the excess phosgene before the reaction solution enters the separation device, and the reaction solution enters the separation device to further remove the residual phosgene and hydrogen chloride;

[0019] (C). Subsequently, the reaction solution enters an alcohol washing device to further process the reaction solution;

[0020] (D). The isocyanate containing an alkoxysilyl group and by-products obtained after the treatment in step (C) are obtained by vacuum distillation and / or rectification to obtain the product isocyanate group alkoxysilane.

[0021] In step (A) of the present invention, the reaction device can be a kettle reactor, a tower reactor, a fixed-bed reactor, or a tubular reactor, preferably a tubular reactor. There is no particular limitation on the aspect ratio of the reaction device, for example, it is 10 - 50, preferably 15 - 35. There is no particular limitation on the internal packing of the reaction device, and preferably it is a non-metallic packing, such as ceramic packing, glass packing, plastic packing like polypropylene (PP), polyethylene (PE), and polyvinyl chloride (PVC), etc. The concentration of the aminoalkoxysilane solution has no particular limitation, for example, it is 1.0 - 20% by mass, preferably 3.0 - 15% by mass.

[0022] In the reaction device, the temperature of the reaction section is -5 to 30 °C, preferably 0 to 25 °C, more preferably 5 to 20 °C.

[0023] The aminoalkoxysilane represented by the general formula (II) is preferably selected from 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropylmethyldimethoxysilane, 1-aminomethyltriethoxysilane, 1-aminomethyltrimethoxysilane, etc.

[0024] Regarding the supply ratio of phosgene in step (A), relative to the aminoalkoxysilane, the molar amount is preferably 1.5 - 30 times, more preferably 3 - 25 times, and further preferably 5 - 20 times.

[0025] The inert organic solvent is an aromatic hydrocarbon, a halogenated aromatic hydrocarbon, a halogenated aliphatic hydrocarbon, an aliphatic ester compound or an aromatic ester compound, an aliphatic hydrocarbon or an aromatic hydrocarbon organic solvent. Examples include aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as octane and decane; alicyclic hydrocarbons such as cyclohexane, methylcyclohexane, and ethylcyclohexane; halogenated aromatic hydrocarbons such as chlorotoluene, chlorobenzene, dichlorobenzene, dibromobenzene, and trichlorobenzene; nitrogen-containing compound classes such as nitrobenzene, N,N-dimethylformamide, N,N-dimethylacetamide, and N,N-dimethylimidazolidinone; ethers such as dibutyl ether, ethylene glycol dimethyl ether, and ethylene glycol diethyl ether; ketones such as heptanone, diisobutyl ketone, methyl isobutyl ketone, and methyl ethyl ketone; fatty acid esters such as ethyl acetate, butyl acetate, amyl acetate, and ethoxyethyl acetate; aromatic carboxylic esters such as methyl salicylate, dimethyl phthalate, dibutyl phthalate, and methyl benzoate, etc. Preferably benzene, toluene, xylene, chlorobenzene, dichlorobenzene, dichloromethane, etc. Using such solvents can significantly reduce the solubility of the polar molecule HCl in the system, improve the removal efficiency of HCl, and reduce the generation of by-products.

[0026] In some specific embodiments, in the reaction device, the feeding rate of the mixed solution of aminoalkoxysilane and inert solvent is 0.5 - 5 mL / min, preferably 1 - 3 mL / min. In the present invention, the residence time of the ammonia solution in the reaction section of the reaction device needs to be controlled according to the type of the reaction device. For example, in a tubular reactor, the residence time is 0.5 - 2 min. Some embodiments show that the reaction of aminoalkoxysilane with phosgene is a very rapid reaction. An excessively long residence time will cause more HCl to react with the reaction solution, resulting in an increase in the content of by-products and affecting the reaction yield;

[0027] In the reaction device, the feeding rate of phosgene is 5 L / h - 30 L / h, preferably 10 L / h - 25 L / h. It can be found in some embodiments that an appropriate phosgene flux can significantly improve the reaction result. Inside the reaction device, an appropriate phosgene flux can quickly remove the HCl produced as a by-product of the reaction, and can also accelerate the rate of removing the excess phosgene at the connection between the reaction device and the separation device, quickly removing the generated HCl, thereby reducing the contact time between hydrogen chloride and alkoxysilane and reducing the generation of by-products. When the rate at which phosgene flow removes HCl is in dynamic equilibrium with the generation rate of HCl, further increasing the phosgene flux will have no promoting effect on the reaction result.

[0028] The excess phosgene is removed at the connection between the reaction device and the separation device, and preferably N2 stripping is used for removal. Passing a stream of nitrogen gas at the connection between the reaction device and the separation device can effectively reduce the residual phosgene and HCl entering the subsequent separation device, and avoid the generation of chlorinated impurities during the separation process. To ensure the phosgene flux, the N2 flux is 2 - 10 L / h. For example, when the phosgene flux is 20 L / h, the N2 flux is 4 L / h; for example, when the phosgene flux is 25 L / h, the N2 flux is 5 L / h; for example, when the phosgene flux is 30 L / h, the N2 flux is 6 L / h.

[0029] The reaction equation is as follows:

[0030]

[0031] The side reaction is mainly the reaction of HCl with the alkoxy group on the alkoxysilane to form monochlorinated impurity a. If there are multiple alkoxy groups in the alkoxysilane, dichlorinated products and trichlorinated products will be gradually formed as the reaction residence time prolongs and the reaction temperature increases;

[0032] The reaction equation is as follows:

[0033]

[0034] where X is amino (-NH2) or isocyanate group (-NCO) or carbamate group

[0035] R is a saturated alkyl or saturated alkoxy group, and the carbon chain length of the alkyl or alkoxy group is C1-C6.

[0036] The separation device used in the present invention preferably uses a thin-film evaporation device, and the temperature of the thin-film evaporation is <50 °C, preferably <40 °C, and more preferably <30 °C.

[0037] The alcohol washing device used in the present invention can be a kettle reactor, a tower reactor, a fixed-bed reactor, or a tubular reactor. Preferably, it is a tower reactor. The aspect ratio of the reaction device has no particular limitation, for example, it is 10-50, preferably 15-35. There is no particular limitation on the internal packing of the reaction device. It can be without packing. Preferably, it is a non-metallic packing, such as ceramic packing, plastic packing polypropylene (PP), polyethylene (PE), and polyvinyl chloride (PVC), etc.

[0038] The temperature of the alcohol washing device is -10 °C to 45 °C, preferably 0 °C to 30 °C, and more preferably 5 °C to 20 °C.

[0039] As is well known, isocyanate groups can react with alcohols to form carbamates under appropriate temperature and catalyst conditions.

[0040] The reaction equation is as follows:

[0041]

[0042] However, the applicant found that due to the special properties of siloxanes, under low temperature and without using a catalyst, alcohols preferentially undergo substitution reactions with the groups on the siloxane group. Therefore, the chloro impurities generated during the reaction can be alcoholyzed back to the target product. During the alcoholysis process, the monochloro impurities generated during the reaction can be effectively converted. However, for the dichloro impurities that may appear during the reaction, they cannot be effectively converted through the alcoholysis process. Therefore, the separation process after the reaction section is necessary, and the separation process can effectively control the generation of dichloro impurities. The alcoholysis reaction equation is as follows:

[0043]

[0044] The selection of the alcohol in the alcohol washing device corresponds to the alkoxy group in the target isocyanate group alkoxysilane. For example, when the target product is 3-isocyanatopropyltriethoxysilane or 3-isocyanatopropylmethyldiethoxysilane, the selected alcohol is ethanol. For example, when the target product is 3-isocyanatopropyltrimethoxysilane or 3-isocyanatopropylmethyldimethoxysilane, the alcohol is methanol.

[0045] The alcohol washing device operates under negative pressure, and the operating pressure is, for example, 0.1 kPa - 6 kPa, preferably 0.15 kPa - 4 kPa. Inside the alcohol washing device, the alcohol substance undergoes a substitution reaction with the chloro impurity to obtain the target product and HCl. The generated HCl can be quickly removed through negative pressure operation. At the same time, the operating pressure can be controlled below the saturated vapor pressure of the alcohol substance at the corresponding operating temperature, and the volatilization of the alcohol substance in the alcohol washing device promotes the rapid removal of HCl, thereby reducing the contact time between hydrogen chloride and alkoxysilane.

[0046] Meanwhile, the present invention needs to control the residence time of the reaction liquid in the alcohol washing device to be 2.5 - 15 min, preferably 5 - 10 min. Some embodiments show that too short a residence time will lead to insufficient alcoholysis reaction, and too long a residence time will cause more isocyanate groups to react with the alcohol substance, resulting in an increase in the content of carbamate impurity b and affecting the reaction yield.

[0047] The present invention preferably recovers the excessive alcohol substance after the alcohol washing operation in the step (C). The recovery method includes the following steps: removing the residual alcohol substance from the upper part of the alcohol washing device through N2 stripping and / or negative pressure operation and entering the alcohol substance recovery step, and purifying the alcohol substance through vacuum distillation and / or rectification. The recovered alcohol substance can re-enter the alcohol washing device.

[0048] The reaction liquid after being treated by the step C in the present invention is a composition containing isocyanate group alkoxysilane, with a chlorine level lower than 1.0% and a carbamate level lower than 1.0%, based on the weight of the isocyanate group alkoxysilane.

[0049] The present invention preferably distills off the non-active solvent from the reaction liquid using a known distillation column after the step (C) to recover the inert organic solvent. The steps are as follows: distilling the reaction liquid of the step (C) to collect the crude product of the inert organic solvent; the crude product is washed with water, dehydrated, and distilled for reuse.

[0050] The present invention needs to further implement the step (D) to provide purified isocyanate group alkoxysilane. The isocyanate group alkoxysilane is the isocyanate group alkoxysilane of the formula (I), which may include one or more of a uretdione structure, an isocyanurate structure, a carbamate structure, a urethane structure, an iminooxadiazinedione structure, a carbodiimide structure, a uretonimine, and a polysilane structure.

[0051] According to requirements, the intermediate product substance can be purified by distillation and / or rectification. When using distillation and / or rectification for purification, the distillation and / or rectification column can be a plate column or a packed column. Specifically, the number of theoretical plates of the distillation and / or rectification column (packed column) is, for example, 2 - 60, preferably 5 - 40. In addition, the top pressure of the distillation column is, for example, 0.1 kPa - 4 kPa, preferably 0.15 kPa - 2.5 kPa. In addition, the top reflux ratio of the distillation and / or rectification column is, for example, 0.01 - 60, preferably 0.1 - 40.

[0052] In the method for preparing the isocyanate group alkoxysilane of the present invention, after purification in step (D), the content of chloro impurity a in the isocyanate group alkoxysilane of formula (I) is less than 5000 ppm, and the content of carbamate impurity b is less than 5000 ppm, based on the weight of the isocyanate group alkoxysilane.

[0053] Compared with the prior art, the present invention has at least the following beneficial effects:

[0054] (1) The method for preparing isocyanate group alkoxysilane provided by the present invention can effectively separate by-products. Using the purge process, the residual amount of by-products can be reduced to ≤5000 ppm, and can reach below 4000 ppm under more optimal conditions; under more optimal conditions, the yield of the product isocyanate group alkoxysilane can reach more than 80%, and the conversion rate of the raw material aminoalkoxysilane can reach more than 98%;

[0055] (2) The method for preparing isocyanate group alkoxysilane provided by the present invention does not use an acid-binding agent, reduces the discharge of waste salts and waste water, and meets the environmental protection requirements.

[0056] (3) The method for preparing isocyanate group alkoxysilane provided by the present invention uses conventional equipment for combination, the equipment is simple, and it is easy to realize industrialization. BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 is a schematic diagram of an apparatus for preparing isocyanate group alkoxysilane provided by the present invention;

[0058] In the figure: 1 - Raw material premixing device; 2 - Raw material outlet; 3 - Reaction device raw material inlet; 4 - Phosgene inlet of reaction device; 5 - Reaction device; 6 - Nitrogen inlet of reaction device; 7 - Phosgene removal outlet of reaction device; 8 - Reaction liquid discharge outlet of reaction device; 9 - Reaction liquid inlet of separation device; 10 - Separation device; 11 - Light component discharge outlet of separation device; 12 - Discharge outlet of separation device; 13 - Reaction liquid inlet of alcohol washing device; 14 - Alcohol washing device; 15 - Alcohol discharge outlet of alcohol washing device; 16 - Reaction liquid discharge outlet of alcohol washing device; 17 - Reaction liquid inlet of rectification device; 18 - Rectification device; 19 - Product discharge outlet of rectification device; 20 - Heavy component discharge outlet of rectification device. Detailed implementation mode

[0059] The present invention will be further described below in conjunction with embodiments, but the present invention is not limited thereby.

[0060] The chloro - impurity a in isocyanate - group - alkoxysilane is qualitatively and quantitatively analyzed by liquid chromatography;

[0061] Instrument: Agilent 1260; Chromatographic column: Agilent Extend C18 RRHD 2.1×100mm 1.8μm; Column temperature: 40°C; Flow rate: 0.2ml / min; Mobile phase: A: pure water, B: pure acetonitrile; Injection volume: 20μL; Detection wavelength: 210nm.

[0062] Example 1

[0063] This example is a preparation method of isocyanate - group - propyltriethoxysilane, which specifically includes the following steps:

[0064] Photochemical process:

[0065] Use a tubular reactor with an inner diameter of 20mm and a length of 500mm, internally filled with regular glass packing;

[0066] Dissolve 30g of 3 - aminopropyltriethoxysilane in 270g of chlorobenzene, premix it in the premixing device - 1, and feed it from the raw material outlet - 2 to the reaction device raw material inlet - 3 through a peristaltic pump at a rate of 2ml / min;

[0067] Pass phosgene gas through the phosgene inlet of the reaction device - 4 at 20L / h, carry out a photochemical reaction in the reaction device - 5, control the reaction temperature of the reaction device at 15°C through a circulating water bath, and at the same time control the residence time of the reaction liquid in the reaction device at 1.5min. Nitrogen is introduced through the nitrogen inlet of the reaction device - 6, and the residual phosgene in the system is removed through the phosgene removal outlet of the reaction device - 7. The reaction liquid flows from the reaction liquid discharge outlet of the reaction device - 8 through the reaction liquid inlet of the separation device - 9 into the separation (thin - film evaporation) device - 10.

[0068] Separation process:

[0069] The reaction solution enters the thin-film evaporation device, and the evaporation temperature is controlled at 30 °C to quickly remove waste gases such as phosgene and hydrogen chloride remaining in the reaction solution. The light components and tail gas are removed through the light-component discharge port -11. The reaction solution enters the alcohol washing device -14 through the discharge port -12 of the separation (thin-film evaporation) device;

[0070] Alcohol washing process:

[0071] The reaction solution enters the alcohol washing device -14 through the reaction solution feed port -13 of the alcohol washing device. The alcohol washing temperature is controlled at 20 °C, the pressure is 2 kPa, and the residence time is 6 min. An alcoholysis substitution reaction is carried out on the chloro impurities generated in the reaction section. At the same time, waste gases such as phosgene and hydrogen chloride remaining in the reaction solution are quickly removed through negative pressure and the evaporation of alcohol substances. The alcohol substances and tail gas are removed through the alcohol discharge port -15 of the alcohol washing device. The reaction solution enters the solvent and tar removal process through the reaction solution discharge port -16 of the alcohol washing device;

[0072] Rectification (solvent and tar removal) process:

[0073] The obtained reaction solution is subjected to solvent removal using a Vigreux column at a pressure of 3 kPa and a bottom temperature of 110 °C. After the solvent removal is completed, the pressure is reduced to 100 Pa and the bottom temperature is raised to 140 °C for tar removal. The distillate is distilled to obtain the product isocyanatopropyltriethoxysilane, with a content of 97.1% and a yield of 88.1%. This finished product is a colorless liquid, and moisture influence needs to be avoided, and it should be stored at low temperature.

[0074] The conditions and results are shown in Table 2.

[0075] Examples 2-12 and Comparative Examples 1-6

[0076] Referring to the operation steps of Example 1, where: in Examples 2-7, parameters such as raw material flux, residence time in the reaction section, and reaction section temperature are changed; in Examples 8-9, the temperature of the alcohol washing step is changed, and in Examples 10-12, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, and 3-aminopropylmethyldimethoxysilane are used as raw materials respectively;

[0077] The conditions and results are shown in Table 2.

[0078] In Comparative Examples 1-4, the kettle-type liquid-phase phosgenation method is used. First, a 1-L reaction device equipped with a stirrer and a thermometer is placed in a water bath. Then, 30 g of aminopropyltriethoxysilane is dissolved in 270 g of chlorobenzene, and then added to the reaction device and stirred, and the temperature is controlled at 5 °C to 25 °C. Phosgene is introduced through the phosgene inlet pipe at a rate of 15-25 L / h for the phosgenation reaction. The subsequent separation operations are the same as those in the examples.

[0079] The difference between Comparative Example 5 and Comparative Example 1 is that the alcohol washing step is not carried out, and the reaction solution obtained in the separation process directly enters the rectification process.

[0080] In Comparative Example 6, an acid-binding agent was used. The type of acid-binding agent used was triethylamine. First, a 1L reaction device equipped with a stirrer and a thermometer was placed in a water bath. Then, 30g of aminopropyltriethoxysilane was dissolved in 190g of chlorobenzene, and then added to the reaction device and stirred. The temperature was controlled at 15°C. Phosgene was introduced from the phosgene inlet pipe at a rate of 20L / h, and 16g of triethylamine dissolved in 80g of chlorobenzene was introduced into the reaction kettle at a rate of 5ml / min simultaneously with phosgene for the photochemical reaction. After the reaction, the reaction solution was centrifuged and filtered to separate the generated acid-binding agent hydrochloride. The subsequent separation operations were the same as those in the examples.

[0081] The conditions and results are shown in Table 3.

[0082] Table 2 Conditions and Results of Examples 1-12 and Table 3 Conditions and Results of Comparative Examples 1-6

[0083] Table 2 Conditions and Results of Examples 1-12

[0084]

[0085] Table 3 Conditions and Results of Comparative Examples 1-6

[0086]

[0087] It can be seen from the above data that the isocyanate group alkoxysilane product prepared by the method of the present invention can effectively reduce the generation of chlorinated impurities without using an acid-binding agent. In some embodiments, the purity of the final product > 95%, the content of chlorinated impurities < 5000ppm, and the overall yield > 75%. In some preferred embodiments, the overall yield > 80%. It effectively avoids the treatment of the acid-binding agent hydrochloride in the traditional photochemical route.

[0088] It should be understood that the specific embodiments described above are only used to explain the present invention and are not used to limit the present invention. Those skilled in the art can understand that under the teaching of this specification, some modifications or adjustments can be made to the present invention. These modifications or adjustments should also be within the scope defined by the claims of the present invention.

Claims

1. A method for preparing isocyanate group alkoxysilane of general formula (Ⅰ), comprising: wherein, R1, R2, and R3 are the same or different, being saturated alkyl or saturated alkoxy groups, and at least one group is a saturated alkoxy group, and the carbon chain length of the alkyl or alkoxy group is C1 - C6; R4 is —(CH2)n—, and n is a positive integer from 1 to 6; (A). Dissolve the amino alkoxysilane of general formula (Ⅱ) in an inert organic solvent and react with phosgene in a reaction device; wherein, in the reaction device, the temperature of the reaction section is -5 to 30 °C; in the reaction device, the feeding rate of the mixed solution of amino alkoxysilane and inert organic solvent is 0.5 - 5 mL / min, and the feeding rate of phosgene is 5 L / h - 30 L / h; the residence time of the ammonia solution in the reaction section of the reaction device is 0.5 - 2 min; wherein, the reaction device is a tubular reactor; (B). Remove the excess phosgene before the reaction solution enters the separation device, and the reaction solution enters the separation device to further remove the residual phosgene and hydrogen chloride; (C). Subsequently, the reaction solution enters the alcohol washing device to further process the reaction solution; wherein, the alcohol selected in the alcohol washing device corresponds to the alkoxy group in the target isocyanate group alkoxysilane, and the temperature of the alcohol washing device is -10 °C to 45 °C; (D). The reaction solution obtained after the treatment in step (C) is obtained by vacuum distillation and / or rectification to obtain the product isocyanate group alkoxysilane.

2. The method according to claim 1, wherein In step (A), the molar amount of phosgene is 1.5 - 30 times that of the amino alkoxysilane.

3. The method according to claim 2, wherein, In step (A), the molar amount of phosgene is 5 - 20 times that of the amino alkoxysilane.

4. The method according to claim 1, wherein In step (A), the reaction temperature is 5 - 20 °C.

5. The method according to claim 1, wherein, In step (B), the separation device is a thin-film evaporation device, and the temperature of the thin-film evaporation is <50 °C.

6. The method according to claim 1, wherein In step (C), the temperature of the alcohol washing device is 0 °C to 30 °C.

7. The method according to claim 1, wherein In step (C), the pressure in the alcohol washing device is 0.1 kPa - 6 kPa.

8. The method according to claim 7, wherein, In step (C), the pressure in the alcohol washing device is 0.15 kPa - 4 kPa.

9. The method according to any one of claims 1 to 7, wherein In step (C), the residence time of the reaction solution in the alcohol washing device is 2.5 - 15 min.

10. The method according to claim 9, wherein, In step (C), the residence time of the reaction solution in the alcohol washing device is 5 - 10 min.

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