Continuous synthesis method of 3-aminopropyltriethoxysilane in a series of pipelining

Abstract

The present invention relates to a method for synthesizing a silane coupling agent, and specifically discloses a tandem pipelined continuous synthesis method for 3-aminopropyltriethoxysilane (KH-550): The synthesis device used includes a pipelined reactor I, a pipelined reactor II, and a collection tank that are connected in sequence; a lithium oxide catalyst coating is provided on the inner wall of the pipelined reactor I, and a nickel oxide catalyst coating is provided on the inner wall of the pipelined reactor II. The tandem pipelined continuous synthesis method includes the following steps: Triethoxysilane and acrylonitrile undergo an addition reaction in the pipelined reactor I; the reaction product flowing out of the pipelined reactor I and hydrogen undergo a hydrogenation reaction in the pipelined reactor II; the reaction product flowing out of the pipelined reactor II is collected and, after post-treatment, 3-aminopropyltriethoxysilane (KH-550) is obtained.

Description

Technical Field

[0001] The present invention relates to a synthesis method of a silane coupling agent, in particular to a tandem pipelining continuous synthesis method of 3-aminopropyltriethoxysilane. Background Art

[0002] 3-aminopropyltriethoxysilane (KH-550) is an important aminoalkylsilane, having two functional groups, namely an amino group and an ethoxy group. It has a wide range of uses and can be used as an excellent glass fiber treating agent, an excellent adhesion promoter, a filler additive for resins, etc., and is widely used in industries such as glass fiber reinforced plastics, coatings, casting, plastics, adhesives, sealants, textile printing and dyeing, etc.

[0003] The synthesis methods of KH-550 can be divided into three methods according to different starting materials:

[0004] 1. Using 3-chloropropyltriethoxysilane and liquid ammonia, through ammonolysis, KH-550 is produced, and hydrogen chloride is produced as a by-product. The reaction characteristics are high pressure, mainly batch reactions in a kettle. In patent CN104961762, Wu Bingbing et al. used a mass ratio of 3-chloropropyltriethoxysilane to liquid ammonia of 1:3, a reaction temperature of 90 °C, a reaction pressure of 4 MPa, and a reaction time of 8 h, and KH-550 was prepared intermittently. After purification, the yield was about 75.6%; Zhang Zhongfa used aluminum isopropoxide and phenyl diethanolamine as catalysts, toluene as a solvent, a mass ratio of 3-chloropropyltriethoxysilane to liquid ammonia of 2:1, a reaction temperature of 62 °C, a reaction pressure of 2.3 MPa, and a reaction time of 2.3 h. The main problems of the ammonolysis method are high reaction pressure and long reaction time. Even with the action of a catalyst, the reaction time and pressure are still relatively high, and it is still mainly an intermittent method at present; in addition, due to raw material reasons, the chlorine-containing salts (mainly ammonium chloride) generated by the reaction have high requirements for equipment and post-treatment.

[0005] (EtO)3Si(CH2)3CI + NH3 → (EtO)3Si(CH2)3NH2 + HCl

[0006] 2. An addition method using triethoxysilane and allylamine as raw materials. This method has an atomic utilization rate of 100%, but β-position addition by-products are easily generated during the reaction, resulting in poor reaction selectivity and low yield. Hu Jianghua et al. (CN105669739) developed a method in which acetone reacts with allylamine first to form a Schiff base ketimine to protect the amino group, and then only γ-position addition products are obtained. The purity of KH-550 in the product is about 99%, and the yield of this method can reach 96%. This method has the problems that the raw material allylamine is not easily available and has a high price.

[0007] (EtO)3SiH + H2C=HC-CH2NH2 → (EtO)3Si(CH2)3NH2

[0008] 3. The hydrogenation method using 2-cyanoethyltriethoxysilane as the raw material. This method is carried out in a batch reactor or a fixed-bed reactor and undergoes hydrogenation reduction under the catalysis of transitional metals such as Raney nickel and cobalt. Kazimierczuk reported that at 5 MPa and 150 °C, using a cobalt metal catalyst, the yield of KH-550 was close to 100% (PL187626B1). However, the raw material 2-cyanoethyltriethoxysilane used in this method has a relatively high price, the reaction pressure is 3 - 5 MPa, the reaction temperature is 120 - 150 °C, and the requirements for the reaction equipment are relatively high.

[0009] (EtO)3SiCH2CH2CN + 2H2 → (EtO)3Si(CH2)3NH2 Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a method for continuously preparing KH-550, which can achieve continuous and stable production and improve production efficiency.

[0011] To solve the above technical problem, the present invention provides a series of pipeline continuous synthesis method of 3-aminopropyltriethoxysilane (KH-550):

[0012] The synthesis device used includes a pipeline reactor I, a pipeline reactor II, and a collection tank that are connected in sequence;

[0013] The inner wall of the pipeline reactor I is provided with a lithium oxide catalyst coating, and the adhesion amount of lithium oxide on the inner wall of the pipeline reactor I is 0.02 - 0.05 g / cm 2 (preferably 0.02 - 0.04 g / cm 2 );

[0014] The inner wall of the pipeline reactor II is provided with a nickel oxide catalyst coating, and the adhesion amount of nickel oxide on the inner wall of the pipeline reactor II is 0.01 - 0.03 g / cm 2 (preferably 0.02 - 0.03 g / cm 2 );

[0015] The series of pipeline continuous synthesis method includes the following steps:

[0016] 1). Addition:

[0017] Pump triethoxysilane and acrylonitrile into the pipeline reactor I at a mass flow rate ratio of 2.2 - 3.2:1 (preferably 2.25 - 3.1:1), and react at a temperature of 100 - 150 °C and a pressure of 1 - 3 MPa (preferably 2.5 - 3 MPa) for 50 - 130 min (preferably 50 - 70 min);

[0018] 2). Hydrogenation:

[0019] The reaction product flowing out of the tubular reactor I and hydrogen enter the tubular reactor II separately, and react at a temperature of 90-120 °C and a pressure of 0.8-2.6 MPa (preferably 1.8-2.2 MPa) for 8-12 min. The mass flow rate ratio of hydrogen to acrylonitrile in step 1) is 0.07-0.13:1 (preferably 0.07-0.09:1);

[0020] 3), Collect the reaction product flowing out of the tubular reactor II, and after post-treatment, obtain 3-aminopropyltriethoxysilane (KH-550).

[0021] As an improvement to the tandem tubular continuous synthesis method of 3-aminopropyltriethoxysilane of the present invention: the inner diameter (diameter) of the tubular reactor I is 4-20 mm, and the tube length is 30-100 m; the inner diameter of the tubular reactor II is 10-50 mm, and the tube length is 10-120 m.

[0022] As a further improvement to the tandem tubular continuous synthesis method of 3-aminopropyltriethoxysilane of the present invention: the post-treatment in step 3) is: the reaction product flowing out of the tubular reactor II is purified by vacuum distillation, and the fraction at 120-122 °C under a pressure of -93.8 kPa is collected to obtain 3-aminopropyltriethoxysilane (KH-550, purity ≥ 99.5%).

[0023] As a further improvement to the tandem tubular continuous synthesis method of 3-aminopropyltriethoxysilane of the present invention:

[0024] The method for setting the lithium oxide catalyst coating on the inner wall of the tubular reactor I includes the following steps:

[0025] A. Preparation of lithium-containing catalyst sol:

[0026] A lithium-containing catalyst sol is prepared by mixing an aqueous lithium salt solution with a concentration of 1.4-1.6 mol / L (preferably 1.5 mol / L) and a nano-silica colloidal solution (i.e., nano-silica sol) with a solid content of 28-32% (preferably 30%) in a volume ratio of 1:1.2-2;

[0027] B. Impregnation:

[0028] The lithium-containing catalyst sol is added (injected) into the tubular reactor I. After filling the inner cavity of the tubular reactor I, it is left standing for 2-3 h, so that a lithium-containing catalyst sol layer is formed on the inner wall of the tubular reactor I; then the excess lithium-containing catalyst sol in the inner cavity of the tubular reactor I is purged with an inert gas (such as nitrogen) (the purging time is about 10-15 min);

[0029] C. Drying:

[0030] Control the temperature of the tubular reactor I at 120 - 180 °C and dry for 2 - 3 h;

[0031] D. After repeating the above impregnation and drying 3 - 5 times in sequence, heat-treat the tubular reactor I at 300 - 600 °C (preferably 450 ± 20 °C) for 5 - 8 h;

[0032] Obtain the tubular reactor I with a lithium oxide catalyst coating provided on the inner wall, and the adhesion amount of lithium oxide on the inner wall of the tubular reactor I is 0.02 - 0.05 g / cm 2 .

[0033] As a further improvement to the tandem tubular continuous synthesis method of 3-aminopropyltriethoxysilane of the present invention: the lithium salt is at least any one of lithium chloride (preferred), lithium perchlorate, lithium hypochlorite, and lithium nitrate (i.e., a mixture of one or more).

[0034] As a further improvement to the tandem tubular continuous synthesis method of 3-aminopropyltriethoxysilane of the present invention:

[0035] The method for providing a nickel oxide catalyst coating on the inner wall of the tubular reactor II includes the following steps:

[0036] a. Preparation of the nickel-containing catalyst sol:

[0037] Mix a nickel salt aqueous solution with a concentration of 0.9 - 1.1 mol / L (preferably 1.0 mol / L) and a nano-silica sol with a solid content of 28 - 32% (preferably 30%) in a volume ratio of 1:1.2 - 2 to prepare a nickel-containing catalyst sol;

[0038] b. Impregnation:

[0039] Add (inject) the nickel-containing catalyst sol into the tubular reactor II. After the inner cavity of the tubular reactor II is filled, let it stand for 2 - 3 h, so that a nickel-containing catalyst sol layer is formed on the inner wall of the tubular reactor II; then purge the excess nickel-containing catalyst sol with an inert gas (such as nitrogen) (the purging time is about 10 - 15 min);

[0040] c. Drying:

[0041] Control the temperature of the tubular reactor II at 150 - 200 °C and dry for 2 - 3 h;

[0042] d. After repeating the above impregnation and drying 3 - 5 times in sequence, heat-treat the tubular reactor II at 400 - 500 °C (preferably 450 ± 20 °C)

[0043] for 3 - 6 h;

[0044] Obtain a tubular reactor II with a nickel oxide catalyst coating on the inner wall, and the adhesion amount of nickel oxide on the inner wall of the tubular reactor II is 0.01 - 0.03 g / cm 2 .

[0045] As a further improvement of the tandem tubular continuous synthesis method of 3-aminopropyltriethoxysilane of the present invention:

[0046] The nickel salt is at least any one of nickel chloride (preferred), nickel nitrate, nickel sulfate (optionally preferred), nickel acetate (i.e., a mixture of one or more).

[0047] As a further improvement of the tandem tubular continuous synthesis method of 3-aminopropyltriethoxysilane of the present invention: the particle size of the nano-silica in the nano-silica colloidal solution is 30 - 50 nm.

[0048] The process route of the present invention is as follows. The present invention uses acrylonitrile and triethoxysilane as starting materials, and prepares KH-550 through two-step reactions of addition and hydrogenation:

[0049]

[0050] The present invention uses acrylonitrile and triethoxysilane as starting materials, completes the addition reaction of acrylonitrile and triethoxysilane through the tubular reactor I, and then completes the hydrogenation reaction through the tubular reactor II, and collects the crude KH-550 product. The product yield is between 82% and 99%. After purification by vacuum distillation, the KH-550 product is obtained.

[0051] In summary, the preparation method of 3-aminopropyltriethoxysilane of the present invention has the following technical advantages:

[0052] 1. The industrial price of 2-cyanoethyltriethoxysilane is high, and the storage and transportation requirements are high, and it is extremely easy to absorb water and deteriorate. The present invention uses easily available and cheap triethoxysilane and acrylonitrile as raw materials, and the directly generated 2-cyanoethyltriethoxysilane undergoes a hydrogenation reaction, avoiding the storage and transportation of 2-cyanoethyltriethoxysilane. At the same time, this reaction has the characteristics of fast reaction speed and high conversion rate. When reacting, triethoxysilane is slightly in excess, which can make acrylonitrile completely react and avoid the continuous hydrogenation of acrylonitrile in the next step.

[0053] That is, using acrylonitrile and triethoxysilane as raw materials, avoiding the use of chlorine-containing raw materials, the process route is more atomically economical, with low raw material unit consumption and environmentally friendly;

[0054] 2. The present invention uses two catalysts, namely, the lithium oxide catalyst used for the addition reaction of triethoxysilane and acrylonitrile; the nickel oxide catalyst used for the hydrogenation of 2-cyanoethyltriethoxysilane.

[0055] In the present invention, the catalyst is attached to the inner wall of the tubular reactor, which has the following advantages: it is convenient to use and not easy to fall off; it has a large specific surface area, can fully contact with the reactants, and has good catalytic effect; it is convenient for continuous production.

[0056] That is, the present invention adopts a series of tubular reactors with the catalyst attached to the inner wall, and the catalyst has good stability and simple operation. The continuous preparation process of KH-550 by addition and hydrogenation is realized. Compared with the original batch process, the production efficiency is higher, the separation and storage of intermediate materials are avoided, and the process conditions are mild. Compared with the "transition metals such as Raney nickel and cobalt" used as catalysts reported by Kazimierczuk, the nickel oxide catalyst adopted in the present invention has the technical advantages of good stability, high dispersion and not easy to agglomerate. Description of the Drawings

[0057] The following further elaborates on the specific implementation manners of the present invention in conjunction with the drawings.

[0058] Figure 1 It is a schematic diagram of the KH550 preparation device. Specific Embodiments

[0059] The following further describes the present invention in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto:

[0060] Device Example 1: A continuous tubular device for preparing KH550, the structure of which is as Figure 1 shown,

[0061] It includes tubular reactor I and tubular reactor II. The outlet of tubular reactor I is connected to the inlet of tubular reactor II through back pressure valve I and check valve; back pressure valve I is used to control the reaction pressure of tubular reactor I; the function of the check valve is to prevent material backflow; the hydrogen inlet is connected to the inlet of tubular reactor II through a pipeline provided with stop valve 6;

[0062] The outlet of the triethoxysilane raw material tank is successively connected to stop valve 5 through stop valve 1, pump I and stop valve 3;

[0063] The outlet of the acrylonitrile raw material tank is successively connected to stop valve 5 through stop valve 2, pump II and stop valve 4;

[0064] Stop valve 5 is connected to the inlet of tubular reactor I;

[0065] The outlet of tubular reactor II is connected to the inlet of the collection tank through back pressure valve II, and back pressure valve II is used to control the reaction pressure of tubular reactor II; the outlet of the collection tank is connected to the reaction liquid outlet through a pipeline with stop valve 7.

[0066] Both the tubular reactor I and the tubular reactor II are tubular reactors with catalysts attached to their inner walls. Specifically:

[0067] The steps for attaching the catalyst to the inner wall of the tubular reactor I include:

[0068] Preparation of the lithium-containing catalyst sol: Mix a 1.5 M (1.5 mol / L) aqueous lithium salt solution and a nano-silica sol (solid content 30%, particle size range 30 - 50 nm) in a volume ratio of 1:1.2 - 2 to prepare a lithium-containing catalyst sol (with certain adsorption and permeability);

[0069] The lithium salt is, for example, lithium chloride;

[0070] Impregnation: Inject the lithium-containing catalyst sol into the tubular reactor I. After filling the pipeline, let it stand for 2 - 3 h, and then blow out the excess lithium-containing catalyst sol with nitrogen for 10 - 15 min;

[0071] Drying: Control the temperature of the tubular reactor I at 120 - 180 °C and dry for 2 - 3 h;

[0072] After repeating the above impregnation and drying 3 - 5 times, place the tubular reactor I in an electric resistance furnace and conduct high-temperature heat treatment in an air atmosphere at a temperature of 300 - 600 °C for 5 - 8 h. Finally, a lithium oxide catalyst coating is attached to the inner wall of the tubular reactor I, and its attachment amount is about 0.02 - 0.05 g / cm 2 .

[0073] Taking lithium chloride as an example, after the lithium chloride solution is mixed with the silica sol and dried, a coating of lithium chloride and silica is formed. After high-temperature treatment, lithium chloride is converted into lithium oxide, and under the action of silica, it adheres to the inner wall of the tubular reactor I.

[0074] The steps for attaching the catalyst to the inner wall of the tubular reactor II include:

[0075] Preparation of the nickel-containing catalyst sol: Mix a 1 M (1 mol / L) aqueous nickel salt solution and a nano-silica colloidal solution (30%, particle size range 30 - 50 nm) in a volume ratio of 1:1.2 - 2 to prepare a nickel-containing catalyst sol;

[0076] The nickel salt is, for example, nickel chloride.

[0077] Impregnation: Inject the nickel-containing catalyst sol into the tubular reactor II. After filling the pipeline, let it stand for 2 - 3 h, and then blow out the excess nickel-containing catalyst sol with nitrogen for 10 - 15 min;

[0078] Drying: Control the temperature of the tubular reactor II at 150 - 200 °C and dry for 2 - 3 h;

[0079] After repeating the impregnation and drying process 3 to 5 times, the tubular reactor II is placed in an electric resistance furnace and subjected to high-temperature heat treatment under a hydrogen atmosphere at a temperature of 400 to 500 °C for 3 to 6 hours. Finally, a nickel catalyst coating is attached to the inner wall of the tubular reactor II, and the attachment amount is about 0.01 to 0.03 g / cm 2 。

[0080] Taking nickel chloride as an example, after mixing the nickel chloride solution with the silica sol and drying, a coating of nickel chloride and silica is formed. After further high-temperature treatment, nickel chloride is converted into nickel oxide, which adheres to the inner wall of the tubular reactor II under the action of silica.

[0081] During actual operation, the stop valves 1 to 6 are all in the open state; when the reaction ends, pump I and pump II, as well as stop valve 6, are closed, and the material in the pipeline is purged with nitrogen; and stop valve 7 is opened to achieve discharging.

[0082] Triethoxysilane and acrylonitrile materials are transported to the tubular reactor I by their respective raw material pumps, and the reaction liquid flowing out of the tubular reactor I flows into the tubular reactor II through a one-way valve and a back pressure valve I. Finally, after the reaction liquid flows into the collection tank, it is purified by vacuum distillation to obtain the product KH-550.

[0083] The products obtained in the following cases are verified by conventional nuclear magnetic resonance, and it is confirmed that they are indeed KH-550.

[0084] Example 1-1. A preparation method of KH-550 includes the following steps:

[0085] I. A catalyst is attached to the inner wall of the tubular reactor I by sequentially performing the following steps:

[0086] Preparation of the lithium-containing catalyst sol: A 1.5 M aqueous lithium salt solution and a nano-silica sol (solid content 30%, particle size range 30 - 50 nm) are mixed in a volume ratio of 1:1.5 to prepare the lithium-containing catalyst sol;

[0087] The lithium salt is lithium chloride;

[0088] Impregnation: Inject the lithium-containing catalyst sol into the tubular reactor I, let it stand for 2 to 3 hours after filling the pipeline, and then purge the excess lithium-containing catalyst sol with nitrogen for 10 to 15 minutes to remove it;

[0089] Drying: Control the temperature of the tubular reactor I at 150 °C and dry for 3 hours;

[0090] After repeating the above impregnation and drying 4 times, the tubular reactor I was placed in an electric resistance furnace for high-temperature heat treatment in an air atmosphere at a temperature of 450 °C for 6 h. Finally, a lithium oxide catalyst coating was attached to the inner wall of the tubular reactor I, and the attachment amount was about 0.03 g / cm 2 .

[0091] Note: Lithium oxide attachment amount = molar consumption of lithium chloride × 42.4 ÷ inner wall area of the tubular reactor I.

[0092] II. The steps for attaching a catalyst to the inner wall of the tubular reactor II are as follows:

[0093] Preparation of the nickel-containing catalyst sol: A 1M nickel salt aqueous solution and a nano-silica sol (30%, particle size range 30 - 50 nm) were mixed in a volume ratio of 1:1.5 to prepare the nickel-containing catalyst sol;

[0094] The nickel salt was nickel chloride.

[0095] Impregnation: Inject the nickel-containing catalyst sol into the tubular reactor II, wait for 2 - 3 h after filling the pipeline, and then blow the excess nickel-containing catalyst sol with nitrogen for 10 - 15 min to remove it;

[0096] Drying: Control the temperature of the tubular reactor II at 180 °C and dry for 2.5 h;

[0097] After repeating the impregnation and drying 4 times, the tubular reactor II was placed in an electric resistance furnace for high-temperature heat treatment in a hydrogen atmosphere at a temperature of 450 °C for 5 h. Finally, a nickel catalyst coating was attached to the inner wall of the tubular reactor II, and the attachment amount was about 0.02 g / cm 2 .

[0098] III. Settings:

[0099] The inner diameter of the tubular reactor I is 10 mm, and lithium oxide is attached to the inner wall as a catalyst (the lithium salt used for catalyst attachment is lithium chloride), and the catalyst (lithium oxide) attachment amount is about 0.03 g / cm 2 .

[0100] The diameter of the tubular reactor II is 30 mm, and nickel is attached to the inner wall as a catalyst (the nickel salt used for catalyst attachment is nickel chloride), and the catalyst (nickel oxide) attachment amount is about 0.02 g / cm 2 .

[0101] Triethoxysilane and acrylonitrile materials are pumped into the tubular reactor I through pump I and pump II at flow rates of 45 g / min and 20 g / min respectively. The reaction temperature is 150 °C, and the reaction residence time is about 60 min. The pressure in the tubular reactor I is stabilized at 2.5 MPa by controlling the back pressure valve I after the tubular reactor I. The reaction liquid flows through the check valve and then into the tubular reactor II. The hydrogen pumping rate is 0.019 m 3 / min (1.6 g / min), the reaction temperature is 110 °C, and the reaction residence time is 10 min. The pressure is stabilized at 2.2 MPa by controlling the back pressure valve II after the tubular reactor II. Finally, the reaction liquid flows into the collection tank and is purified by vacuum distillation. The fraction at 120 - 122 °C under a pressure of -93.8 kPa is collected to obtain the KH-550 product (purity ≥ 99.5%).

[0102] The lengths of the two tubular reactors can be calculated based on the reaction residence time and flow rate. For example, the length of the tubular reactor I is about 58 m; the length of the tubular reactor II is about 100 m.

[0103] When the dosages of triethoxysilane and acrylonitrile are 90 g and 40 g respectively, 165 g of KH-550 is obtained. The calculation formula for the yield of KH-550 is as follows:

[0104]

[0105] Among them, m2 is the product mass of KH-550, and m1 is the dosage of acrylonitrile.

[0106] Examples 1-2 to 1-8

[0107] By changing the reaction temperatures of the tubular reactors I and II, the product yields are detected, and the following data (Table 1) are obtained.

[0108] Table 1. Influence of reaction temperature on the yield of KH-550

[0109]

[0110] The purity of the KH-550 product obtained in the above cases is ≥ 99.5%.

[0111] Examples 2-1 to 2-4

[0112] Relative to Example 1-1, the tube lengths of the tubular reactor I and the tubular reactor II are changed, thereby correspondingly changing the reaction residence time; while the catalyst attachment density remains unchanged, that is, the attachment amount of the catalyst (lithium oxide) in the tubular reactor I is still about 0.03 g / cm 2 ; the attachment amount of the catalyst (nickel oxide) in the tubular reactor II is still about 0.02 g / cm 2The rest is the same as in Example 1-1. The product yield was detected, and the following data was obtained (Table 2).

[0113] Table 2. Influence of reaction residence time on the yield of KH-550

[0114] Group <![CDATA[τ1(min)]]> <![CDATA[τ2(min)]]> Yield of KH-550 (%) Example 2-1 60 10 99 Example 2-2 70 10 99 Example 2-3 50 10 95 Example 2-4 60 8 93 Example 2-5 60 12 98

[0115] The purity of the KH-550 product obtained in the above case is ≥99.5%.

[0116] Examples 3-1 to 3-4

[0117] Compared with Example 1-1, by adjusting the backpressure valves after the tubular reactor I and the tubular reactor II, the reaction pressure was changed, and the rest was the same as in Example 1-1. The product yield was detected, and the following data was obtained (Table 3).

[0118] Table 3. Influence of reaction pressure on the yield of KH-550

[0119]

[0120] The purity of the KH-550 product obtained in the above case is ≥99.5%.

[0121] Examples 4 series and Comparative Example 1 series

[0122] Compared with Example 1-1, the flow rates of triethoxysilane and acrylonitrile materials were changed, but the total flow rate (the sum of the flow rates of triethoxysilane and acrylonitrile materials) was kept constant, so as to ensure that the residence time of the reaction in the tubular reactors I and II remained basically unchanged, and the rest was the same as in Example 1-1. Thus, corresponding Examples 4-1 to 4-2 (the purity of the product is ≥99.5%) were obtained, and Comparative Examples 1-1 and 1-2 were obtained. The product yield was detected, and the following data was obtained (Table 4).

[0123] Table 4. Influence of the material flow rate ratio on the yield of KH-550

[0124]

[0125] Examples 5 series and Comparative Example 2 series

[0126] Compared with Example 1-1, the flow rate of triethoxysilane was kept constant, the usage ratio of hydrogen to triethoxysilane raw materials was changed, and the tube length II of the tubular reactor was adjusted accordingly, so as to ensure that the residence time of the reaction remained basically unchanged, and the rest was the same as in Example 1-1. Thus, corresponding Examples 5-1 to 5-2 (the purity of the product is ≥99.5%) were obtained, and Comparative Examples 2-1 and 2-2 were obtained. The product yield was detected, and the following data was obtained (Table 5).

[0127] Table 5. Influence of material flow rate ratio on the yield of KH-550

[0128]

[0129] Example 6 series: Compared with Example 1-1, only the type of salt used for attaching the catalyst to the inner walls of the tubular reactor I and the tubular reactor II is changed, the molar concentration of the lithium aqueous solution remains unchanged, and the volume ratio to the nano-silica sol remains unchanged; the molar concentration of the nickel aqueous solution remains unchanged, and the volume ratio to the nano-silica sol remains unchanged; the rest is the same as Example 1-1. The product yield was detected, and the following data was obtained (Table 6).

[0130] Table 6. Influence of lithium salt and nickel salt on the yield of KH-550

[0131]

[0132] The purity of the product ≥ 99.5%

[0133] Note: Precursors of different metal salts have a great influence on the morphology of the formed metal oxides, and the morphology of the metal oxides is directly related to the catalytic activity.

[0134] Example 7 series and Comparative Example 3 series, change the attachment amount of lithium oxide in the tubular reactor I in Example 1-1 from 0.03 g / cm 2 to 0.02 g / cm 2 , 0.04 g / cm 2 , 0.01 g / cm 2 , 0.015 g / cm 2 , that is, during the process of attaching the catalyst to the inner wall of the tubular reactor I, the number of repetitions of impregnation and drying is adjusted accordingly, and the rest is the same as Example 1-1; the results are as follows in Table 7.

[0135] Table 7. Influence of lithium attachment amount in the tubular reactor I on the yield of KH-550

[0136]

[0137] Example 8 series and Comparative Example 4 series, change the attachment amount of nickel oxide in the tubular reactor II in Example 1-1 from 0.02 g / cm 2 to 0.03 g / cm 2 , 0.005 g / cm 2 , 0.035 g / cm 2 , that is, during the process of attaching the catalyst to the inner wall of the tubular reactor II, the number of repetitions of impregnation and drying is adjusted accordingly, and the rest is the same as Example 1-1. The results are as follows in Table 8.

[0138] Table 8. Effect of nickel adhesion on KH-550 yield in pipeline reactor II

[0139]

[0140] Comparative Example 5-1: In the lithium attachment treatment of the pipeline reactor I in Example 1-1, the high-temperature heat treatment temperature was changed from 450°C to 280°C and 650°C, and the rest was the same as Example 1-1. The results are shown in Table 9 below.

[0141] Table 9. Effect of catalyst heat treatment temperature on reaction in pipeline reactor I

[0142]

[0143] Note: The high-temperature heat treatment process affects the formation process of lithium oxide. Too high or too low temperature may cause changes in the particle size of lithium oxide, ultimately affecting the activity of the catalyst.

[0144] Comparative Example 6-1: In the nickel attachment treatment of the pipeline reactor II in Example 1-1, the high-temperature heat treatment temperature was changed from 450°C to 300°C and 550°C, and the rest was the same as Example 1-1. The results are shown in Table 10 below.

[0145] Table 10. Effect of Catalyst Heat Treatment Temperature on the Reaction in Pipeline Reactor 1

[0146]

[0147] Finally, it should be noted that the above examples are only some specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and there are many variations. All variations that can be directly derived or associated with the content disclosed by a person skilled in the art should be considered as the protection scope of the present invention.

Claims

1. A tandem pipelined continuous synthesis method of 3-aminopropyltriethoxysilane, characterized in that: The synthesis device used includes a pipelined reactor I, a pipelined reactor II, and a collection tank that are connected in sequence; The inner wall of the tubular reactor I is provided with a lithium oxide catalyst coating, and the adhesion amount of lithium oxide on the inner wall of the tubular reactor I is 0.02 - 0.05 g / cm 2 ; The inner wall of the tubular reactor II is provided with a nickel oxide catalyst coating, and the adhesion amount of nickel oxide on the inner wall of the tubular reactor II is 0.01 to 0.03 g / cm 2 ; The tandem pipelined continuous synthesis method includes the following steps: 1). Addition: Pump triethoxysilane and acrylonitrile into the pipelined reactor I according to a mass flow rate ratio of 2.2 - 3.2:1, and react at a temperature of 100 - 150 °C and a pressure of 1 - 3 Mpa for 50 - 130 min; 2). Hydrogenation: The reaction product flowing out of the pipelined reactor I and hydrogen enter the pipelined reactor II respectively, and react at a temperature of 90 - 120 °C and a pressure of 0.8 - 2.6 Mpa for 8 - 12 min. The mass flow rate ratio of hydrogen to acrylonitrile in step 1) is 0.07 - 0.13:1; 3). Collect the reaction product flowing out of the pipelined reactor II, and after post-treatment, obtain 3-aminopropyltriethoxysilane.

2. The tandem pipelined continuous synthesis method of 3-aminopropyltriethoxysilane according to claim 1, characterized in that: The inner diameter of the pipelined reactor I is 4 - 20 mm, and the pipe length is 30 - 100 m; the inner diameter of the pipelined reactor II is 10 - 50 mm, and the pipe length is 10 - 120 m.

3. The tandem pipe continuous synthesis method of 3-aminopropyltriethoxysilane according to claim 1 or 2, characterized in that The post-treatment in step 3) is: The reaction product flowing out of the pipelined reactor II is purified by vacuum distillation, and the fraction at 120 - 122 °C under a pressure of -93.8 kPa is collected to obtain 3-aminopropyltriethoxysilane.

4. The tandem pipelined continuous synthesis method of 3-aminopropyltriethoxysilane according to claim 3, characterized in that: The method for setting the lithium oxide catalyst coating on the inner wall of the pipelined reactor I includes the following steps: A. Preparation of lithium-containing catalyst sol: Mix an aqueous lithium salt solution with a concentration of 1.4 - 1.6 mol / L and a nano-silica colloid solution with a solid content of 28 - 32% in a volume ratio of 1:1.2 - 2 to prepare a lithium-containing catalyst sol; B. Impregnation: Add the lithium-containing catalyst sol into the pipelined reactor I. After filling the inner cavity of the pipelined reactor I, let it stand for 2 - 3 h, so that a lithium-containing catalyst sol layer is formed on the inner wall of the pipelined reactor I; then blow away the excess lithium-containing catalyst sol in the inner cavity of the pipelined reactor I with an inert gas; C. Drying: Control the temperature of the pipelined reactor I at 120 - 180 °C and dry for 2 - 3 h; D. Repeat the above impregnation and drying 3 - 5 times in sequence, and then heat-treat the pipelined reactor I at a high temperature of 300 - 600 °C for 5 - 8 h; Obtain a tubular reactor I with a lithium oxide catalyst coating on the inner wall, and the adhesion amount of lithium oxide on the inner wall of the tubular reactor I is 0.02 to 0.05 g / cm 2 .

5. The tandem pipe-in-pipe continuous synthesis method of 3-aminopropyltriethoxysilane according to claim 4, characterized in that: The lithium salt is at least any one of lithium chloride, lithium perchlorate, lithium hypochlorite, and lithium nitrate.

6. The tandem pipelined continuous synthesis method of 3-aminopropyltriethoxysilane according to claim 5, characterized in that: The method for setting the nickel oxide catalyst coating on the inner wall of the pipelined reactor II includes the following steps: a. Preparation of nickel-containing catalyst sol: Mix an aqueous nickel salt solution with a concentration of 0.9 - 1.1 mol / L and a nano-silica colloid solution with a solid content of 28 - 32% in a volume ratio of 1:1.2 - 2 to prepare a nickel-containing catalyst sol; b. Impregnation: Add the nickel-containing catalyst sol into the tubular reactor II. After the inner cavity of the tubular reactor II is filled, let it stand for 2 to 3 hours, so that a nickel-containing catalyst sol layer is formed on the inner wall of the tubular reactor II; then blow off the excess nickel-containing catalyst sol with an inert gas; c. Drying: Control the temperature of the tubular reactor II at 150 to 200 °C and dry for 2 to 3 hours; d. After repeating the above impregnation and drying 3 to 5 times in sequence, heat-treat the tubular reactor II at a high temperature of 400 to 500 °C for 3 to 6 hours; Obtain a tubular reactor II with a nickel oxide catalyst coating on the inner wall, and the adhesion amount of nickel oxide on the inner wall of the tubular reactor II is 0.01 - 0.03 g / cm 2 .

7. The tandem pipelining continuous synthesis method of 3-aminopropyltriethoxysilane according to claim 6, characterized in that: The nickel salt is at least any one of nickel chloride, nickel nitrate, nickel sulfate, and nickel acetate.

8. The tandem tubular continuous synthesis method of 3-aminopropyltriethoxysilane according to claim 7, characterized in that: The particle size of the nano-silica in the nano-silica sol solution is 30 to 50 nm.

Images