A kind of preparation method of azosilane coupling agent

Abstract

The invention discloses a method for preparing an azosilane coupling agent, wherein amino ester is used as a raw material, and first reacts with chlorosilane to obtain amino ester silane, and then reacts with a hydrazine compound under the action of a catalyst to obtain an azosilane coupling agent precursor; finally, the precursor is reacted with an oxidant to obtain a final target product. The invention uses chlorosilane as a raw material, which is common and easy to obtain, has a low reaction temperature, mild operating conditions, a high reaction rate, few side reactions, a high and stable product yield and purity, and is easy to industrialize.

Description

Technical Field

[0001] The invention relates to a method for preparing an azosilane coupling agent, and belongs to the technical field of chemical synthesis. Background Art

[0002] Silane coupling agents are a class of low molecular weight organic silicon compounds with special structures, which are widely used in rubber, plastic, glass fiber, filling composite materials, epoxy packaging materials, elastomers, coatings, adhesives and sealants. Due to its special molecular structure, silane coupling agents can interact with both hydroxyl groups in inorganic substances and long molecular chains in organic polymers, coupling two materials with different properties, thereby improving various properties of biomaterials. Therefore, silane coupling agents have become one of the indispensable additives in the materials industry.

[0003] However, for rubber products that require high tensile strength and wear resistance, especially for tires and conveyor belts, etc., rubber products add silica as an effective reinforcing filler to improve the physical properties of rubber products. Since the surface of silica contains a large number of silanol groups, it has a high surface energy, can form hydrogen bonds, shows hydrophilicity, and is very easy to agglomerate with each other, resulting in a weakening of the rubber-filler interaction and a decrease in the reinforcement effect. Secondly, the hydroxyl groups will also cause the rubber to delay vulcanization. Therefore, it is necessary to modify the surface of silica. Generally, silane coupling agents can react with the hydroxyl groups of silica after hydrolysis to reduce the number of hydroxyl groups, thereby improving the physical and mechanical properties of the composite material. Among them, azosilane, with its unique azo structure, has a unique application in rubber modification.

[0004] CN105504370A and CN105001252A disclose an azo-silane coupling agent, the chemical formula of which is: (R 1 ) 3-a (R 2 ) a Si-R I -NH-C(O)-N=NR 4 (I), there are two methods for preparing the azo-silane coupling agent, one of which is to react hydrazine (such as ethyl carbazate, phenylhydrazine) and isocyanate silane (such as 3-isocyanatepropyl (triethoxysilane)) to obtain a precursor, and then oxidize the precursor with an oxidant (such as NBS / pyridine) to obtain the final azo-silane coupling agent; the other is to react hydrazine with acyl chloride, and then oxidize the reaction product with an oxidant, and the oxidized product reacts with aminosilane to obtain the final azo-silane coupling agent. The reagents such as isocyanate silane and oxidant used in these two methods are expensive, and the production cost is high; the yield of the obtained product is less than 90%, and the yield and purity are low. Summary of the invention

[0005] The object of the present invention is to provide a method for preparing an azosilane coupling agent, wherein the raw materials are common and easily available, the operating conditions are mild, the reaction rate is high, the side reactions are few, and the method is easy to industrialize.

[0006] The azosilane coupling agent of the present invention has the chemical formula shown in the following formula (I):

[0007] (R1) x (R2) 3-x -Si-R3-NH-C(O)-N=N-R4 (Ⅰ)

[0008] in:

[0009] --R1 is hydroxyl, C1-C 18 Alkyl, C1-C 18 Alkoxy, C5-C 18 Cycloalkyl, C6-C 18 For example: -OH; -CH3; -CH2CH3; -(CH2)2CH3; -(CH2)3CH3; -(CH2)5CH3; -(CH2) 10 CH3; -(CH2) 15 CH3; -(CH2) 17 CH3;-O-CH3;-O-CH2CH3;-O-(CH2)2CH3;-O-(CH2)5CH3;-O-(CH2) 10 CH3; -O-(CH2) 17 CH3; -C5H9; -C6H 11 ; -C6H5; -CH2-C6H5; -C6H4-CH3, etc.

[0010] --R2 is C1-C 18 Alkyl, C1-C 18 Alkoxy, C5-C 18 Cycloalkyl, C6-C 18 For example: -CH3; -CH2CH3; -(CH2)2CH3; -(CH2)3CH3; -(CH2)5CH3; -(CH2) 10 CH3; -(CH2) 15 CH3; -(CH2) 17 CH3;-O-CH3;-O-CH2CH3;-O-(CH2)2CH3;-O-(CH2)5CH3;-O-(CH2) 10 CH3; -O-(CH2) 17 CH3; -C5H9; -C6H 11 ; -C6H5; -CH2-C6H5; -C6H4-CH3, etc.

[0011] --x is equal to 1, 2, or 3.

[0012] --R3 is C1-C 18 Alkylene, C6-C 18 For example: -CH2-; -CH2 CH2-; -CH2CH2CH2-; -(CH2)5-; -(CH2) 10 -; -(CH2) 15 -; -(CH2) 18 -; -C6H4-; -CH2-C6H4-; -C6H4-CH2-, etc.

[0013] --R4 is C1-C 18 Alkyl, C1-C 18 Alkoxy, C5-C 18 Cycloalkyl, C6-C 18 The aromatic, acyl, or ester groups may also be substituted acyl or ester groups. For example: -CH3; -CH2CH3; -(CH2)2CH3; -(CH2)3CH3; -(CH2)5CH3; -(CH2) 10 CH3; -(CH2) 15 CH3; -(CH2) 17 CH3;-O-CH3;-O-CH2CH3;-O-(CH2)2CH3;-O-(CH2)5CH3;-O-(CH2) 10 CH3; -O-(CH2) 17 CH3; -C5H9; -C6H 11 ; -C6H5; -CH2-C6H5; -C6H4-CH3; -C(O)-CH3; -C(O)-CH2CH3; -CH2-C(O)-CH3; -C(O)-O-CH3; -C(O)-O-CH2CH3; -CH2-C(O)-O-CH3; -C(O)-CH2-O-CH3 (methoxyacetyl), etc.

[0014] The preparation method of the above-mentioned azosilane coupling agent comprises the following steps:

[0015] (1) reacting an amino ester of formula (II) with a chlorosilane of formula (III) to obtain an amino ester silane of formula (IV);

[0016] (2) reacting the amino ester silane of formula (IV) with the hydrazine compound of formula (V) in the presence of a catalyst to obtain an azosilane coupling agent precursor of formula (VI);

[0017] (3) Finally, the azosilane coupling agent precursor of formula (VI) is reacted with an oxidant to obtain the final target product, i.e., the azosilane coupling agent of formula (I).

[0018] Furthermore, in step (1), the structural formula of the amino ester is:

[0019] NH2-C(O)-O-R5(Ⅱ)

[0020] In formula (II), R5 is C1-C 18 Alkyl, C5-C 18 Cycloalkyl, C6-C 18 For example: -CH3; -CH2CH3; -(CH2)2CH3; -(CH2)3CH3; -(CH2)5CH3; -(CH2) 10 CH3; -(CH2) 15 CH3; -(CH2) 17 CH3; -C5H9; -C6H 11 ; -C6H5; -CH2-C6H5; -C6H4-CH3, etc.

[0021] Furthermore, in step (1), the structural formula of the chlorosilane is:

[0022] (R1) x (R2) 3-x -Si-R3-Cl(Ⅲ)

[0023] In formula (III), the definitions of R1, R2, R3 and X are consistent with those in the above formula (I).

[0024] Furthermore, in step (1), the structural formula of the aminoester silane obtained is:

[0025] (R1) x (R2) 3-x -Si-R3-NH-C(O)-O-R5(Ⅳ)

[0026] In formula (IV), the definitions of R1, R2, R3 and x are consistent with those in the above formula (I), and the definition of R5 is consistent with that in the above formula (II).

[0027] Furthermore, in step (1), the reaction is carried out in the presence of an organic solvent, and the organic solvent is used as a reaction medium, preferably an organic amine organic solvent, and at least one of pyridine, triethylamine, N,N-dimethylaniline (DMA), tri-n-butylamine, etc. can be selected. On the one hand, such organic solvents can improve the dispersibility of the reaction as an organic solvent and provide a reaction medium for the reaction. On the other hand, they can act as an acid binding agent to remove the hydrogen chloride generated by the reaction, promote the reaction to proceed in the forward direction, and improve the yield of the reaction.

[0028] Furthermore, in step (1), the mass ratio of the organic solvent to the amino ester of formula (II) can be (2-5):1, for example, 2:1, 3:1, 4:1, 5:1.

[0029] Furthermore, in step (1), the molar ratio of the chlorosilane of formula (III) to the amino ester of formula (II) is 1:(1-1.2), for example, 1:1, 1:1.1, 1:1.2.

[0030] Furthermore, in step (1), the chlorosilane of formula (III) is preferably added dropwise to the mixture of the amino ester of formula (II) and the organic solvent, the dropping temperature is 40°C to 70°C, for example, 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, and the dropping time is 30min to 45min, for example, 30min, 35min, 40min, 45min.

[0031] Furthermore, in step (1), after the dropwise addition is completed, the reaction is continued at 40°C to 70°C for 30min to 90min. The reaction time can be 40°C, 45°C, 50°C, 55°C, 60°C, 65°C, 70°C, and the reaction time can be 30min, 40min, 50min, 60min, 70min, 80min, 90min.

[0032] Furthermore, in step (1), after the reaction is completed, the by-products are filtered out, and the filtrate is subjected to reduced pressure distillation to recover the organic solvent to obtain the amino ester silane of formula (IV). The reduced pressure distillation temperature varies depending on the type of organic solvent selected, and the vacuum degree of the reduced pressure distillation is generally 0.08 MPa to 0.1 MPa.

[0033] Further, in step (2), the structural formula of the hydrazine compound is:

[0034] NH2-NH-R4(V)

[0035] In formula (V), R4 has the same definition as in the above formula (I).

[0036] Furthermore, in step (2), the structural formula of the azosilane coupling agent precursor is:

[0037] (R1) x (R2) 3-x -Si-R3-NH-C(O)-NH-NH-R4(VI)

[0038] In formula (VI), the definitions of R1, R2, R3, R4 and x are consistent with those in the above formula (I).

[0039] Furthermore, in step (2), the molar ratio of the hydrazino compound of formula (V) to the chlorosilane of formula (III) is (0.9-1.1):1, for example, 0.9:1, 1:1, 1.1:1.

[0040] Furthermore, in step (2), the catalyst is an ethanol solution of sodium ethoxide with a mass fraction of 25% to 30%, and the mass ratio of the ethanol solution of sodium ethoxide with a mass fraction of 25% to 30% to the hydrazine compound of formula (V) is (5% to 12%):1, for example, 5%:1, 6%:1, 7%:1, 8%:1, 9%:1, 10%:1, 11%:1, 12%:1. The catalyst is sodium ethoxide. Since sodium ethoxide is relatively active, it will quickly decompose into sodium hydroxide and ethanol when dissolved in water, and is relatively stable in ethanol solution. Therefore, it is selected to be added in the form of ethanol solution. The sodium ethoxide ethanol solution of this concentration is convenient for feeding and makes the reaction more gentle.

[0041] Furthermore, in step (2), the reaction is carried out in an organic solvent, and the organic solvent can be an aromatic hydrocarbon organic solvent, such as one or more of anhydrous toluene, isopropylbenzene, diisopropylbenzene, and benzene, and the mass ratio of the organic solvent to the hydrazine compound of formula (V) is (2 to 6):1, for example, 2:1, 3:1, 4:1, 5:1, 6:1.

[0042] Furthermore, in step (2), it is preferred that the amino ester silane of formula (IV), the catalyst and the organic solvent are first mixed, and then the hydrazine compound solution of formula (V) is added dropwise thereto.

[0043] Furthermore, in step (2), the temperature is maintained at 45°C to 65°C, for example, 45°C, 50°C, 55°C, 60°C, 65°C, during and after the raw materials are added. After all the raw materials are added, the reaction is continued at this temperature for 30min to 120min, for example, 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, 120min.

[0044] Further, in step (2), after the reaction is completed, a quencher is added to terminate the reaction, the quencher is pure acetic acid, and the mass ratio of acetic acid to the hydrazine compound of formula (V) is (0.5% to 5%): 1, for example 0.5%: 1, 1%: 1, 1.5%: 1, 2%: 1, 2.5%: 1, 3%: 1, 3.5%: 1, 4%: 1, 4.5%: 1, 5%: 1.

[0045] Furthermore, in step (2), the temperature of the quenching reaction is 20°C to 30°C, for example, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, and the time of the quenching reaction is 5 min to 15 min, for example, 5 min, 10 min, 15 min.

[0046] Furthermore, in step (2), after the quenching reaction is completed, the reaction solution is cooled and crystallized, and the obtained crystals are separated, washed, and dried to obtain an azosilane coupling agent precursor. The crystallization temperature is 20°C to 30°C, for example, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, and the crystallization time is 1h to 3h, for example, 1h, 1.5h, 2h, 2.5h, 3h. The obtained crystals are washed with isopropyl ether, and the mass ratio of isopropyl ether to the hydrazine compound of formula (V) is (2 to 4):1, for example, 2:1, 3:1, 4:1. Drying can be carried out by vacuum drying, with a drying temperature of 55°C to 65°C, for example 55°C, 56°C, 57°C, 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C, 65°C, a drying pressure of -0.08MPa to -0.1MPa, i.e., a vacuum degree of 0.08MPa to 0.1MPa, and a drying time of 0.5h to 3h, for example 0.5h, 1h, 1.5h, 2h, 2.5h, 3h.

[0047] Further, in step (3), the oxidant is one of dichloroisocyanuric acid (TCCA) / acid-binding agent oxidation system, sodium bromide / chlorine / acid-binding agent oxidation system, diacetoxyphenyliodide (PIDA), bis(trifluoroacetoxy)phenyliodide (PIFA), etc. Among them, the acid-binding agent can be an alkaline substance such as pyridine and triethylamine.

[0048] Further, in step (3), in the dichloroisocyanuric acid (TCCA) / acid binding agent oxidation system, dichloroisocyanuric acid (TCCA) acts as an oxidant, and the acid binding agent can better promote the oxidation reaction. The molar ratio of dichloroisocyanuric acid (TCCA) to the hydrazine compound of formula (V) is (0.5-2.5):1, for example, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1. The mass ratio of the acid binding agent to the hydrazine compound of formula (V) is (5%-10%):1, for example, 5%:1, 6%:1, 7%:1, 8%:1, 9%:1, 10%:1.

[0049] Further, in step (3), when the oxidant is a sodium bromide / chlorine / acid binding agent oxidation system, the bromine generated by the reaction of sodium bromide and chlorine acts as an oxidant, and the acid binding agent can better promote the oxidation reaction. The molar ratio of sodium bromide to the hydrazine compound of formula (V) is (0.5-2.5):1, for example, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1. Chlorine is continuously introduced into the reaction system, and the pressure in the reaction system is ensured to be below 0.1Mpa to ensure safety. The mass ratio of the acid binding agent to the hydrazine compound of formula (V) is (5%-10%):1, for example, 5%:1, 6%:1, 7%:1, 8%:1, 9%:1, 10%:1.

[0050] Furthermore, in step (3), the molar ratio of diacetoxyphenyliodoacetyl (PIDA) to the hydrazine compound of formula (V) is (0.5-2.5):1, for example, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1.

[0051] Furthermore, in step (3), the molar ratio of bis(trifluoroacetoxy)phenyliodopropene (PIFA) to the hydrazine compound of formula (V) is (0.5-2.5):1, for example, 0.5:1, 1:1, 1.5:1, 2:1, 2.5:1.

[0052] Furthermore, in step (3), the reaction is carried out in the presence of an organic solvent, and the organic solvent may be at least one of halogenated hydrocarbons, ethers, nitriles, amides, etc., for example, one or more of dichloromethane, tetrahydrofuran, N,N-dimethylamide, acetonitrile, methyl tert-butyl ether, diethyl ether, etc., and the mass ratio of the organic solvent to the azosilane coupling agent precursor of formula (VI) is (1.5-4):1, for example, 1.5:1, 2:1, 2.5:1, 3:1, 3.5:1, 4:1.

[0053] Furthermore, in step (3), there is no special requirement for the mixing order of the reactants. Preferably, dichloroisocyanuric acid (TCCA), diacetoxyphenyliodoacetyl (PIDA), and bis(trifluoroacetoxy)phenyliodoacetyl (PIFA) are added dropwise, and sodium bromide is added in the form of solid powder.

[0054] Furthermore, in step (3), the reaction temperature is 20°C to 35°C, for example, 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C, 30°C, 31°C, 32°C, 33°C, 34°C, 35°C, and the reaction time is 30min to 60min, for example, 30min, 35min, 40min, 45min, 50min, 55min, 60min.

[0055] Furthermore, in step (3), after the reaction is completed, the reaction solution is post-treated to obtain the final product, and the post-treatment includes: recovering the organic solvent by vacuum rotary evaporation, washing the residue with a mixture of heptane and isopropyl ether (volume ratio of 1:1), filtering after washing, and vacuum rotary evaporating the filtrate to obtain the final product.

[0056] Furthermore, in step (3), the mass ratio of the mixture of heptane and isopropyl ether to the mass ratio of the azosilane coupling agent precursor of formula (VI) is (0.5-2):1, for example, 0.5:1, 1:1, 1.5:1, 2:1.

[0057] Furthermore, in step (3), the drying temperature of the two vacuum rotary dryings is 55° C. to 65° C., and the drying pressure is -0.08 MPa to -0.1 MPa. The purpose of the first vacuum rotary drying is to remove the organic solvent, and the purpose of the second vacuum rotary drying is to remove the detergent (a mixture of heptane and isopropyl ether).

[0058] Furthermore, in steps (1), (2) and (3), the reaction processes are all carried out under the protection of an inert gas such as nitrogen.

[0059] The present invention has the following beneficial effects:

[0060] (1) The present invention uses chlorosilane as a raw material. This raw material is common and easily available, is the raw material for a variety of organosilane products, and has high reaction activity, which is more conducive to industrial production.

[0061] (2) The present invention uses pyridine, triethylamine, N,N-dimethylaniline (DMA), tri-n-butylamine and other organic amines as the organic solvent for the first step reaction, which can also serve as an acid binding agent to neutralize the hydrochloric acid generated by the reaction, thereby promoting the reaction to proceed in the forward direction.

[0062] (3) The present invention uses an ethanol solution of sodium ethoxide as a strong catalyst for the second step reaction, which has a mild reaction, helps to improve the reaction efficiency, shortens the reaction time, and reduces the production cost.

[0063] (4) The oxidant used in the present invention is one of the oxidation system of dichloroisocyanuric acid (TCCA) / acid-binding agent (pyridine or triethylamine), the oxidation system of sodium bromide / chlorine / acid-binding agent (pyridine or triethylamine), diacetoxyphenyliodide (PIDA), and bis(trifluoroacetoxy)phenyliodide (PIFA). The oxidation system has a low price, high oxidation efficiency, short reaction time, and a more gentle and controllable oxidation process, so that the oxidation reaction proceeds more thoroughly in the forward direction. Among them, the more preferred oxidant is the oxidation system of dichloroisocyanuric acid (TCCA) / acid-binding agent, because the oxidant not only has a high oxidation efficiency, but is also cheap and easy to obtain, and the yield and product purity of the obtained azosilane coupling agent are higher.

[0064] (5) The preparation method provided by the present invention has low reaction temperature, mild operating conditions, high reaction rate, few side reactions, high and stable product yield and purity, and is easy for industrial production.

[0065] (6) The azosilane coupling agent obtained by the present invention can be used alone or in combination with other types of coupling agents in rubber, especially tire rubber, which greatly improves the mechanical properties, weather resistance, dispersibility, formability and process operability of the rubber. DETAILED DESCRIPTION

[0066] The following is a description of exemplary embodiments of the present invention, including various details of the embodiments of the present invention to facilitate understanding, which should be considered as merely exemplary. Therefore, it should be recognized by those of ordinary skill in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the present invention. Similarly, for the sake of clarity and conciseness, descriptions of well-known functions, operations and structures are omitted in the following description. The methods described in the following embodiments, unless otherwise specified, are conventional methods; the materials, unless otherwise specified, can be obtained from commercial sources.

[0067] In the following examples and comparative examples, unless otherwise specified, the concentrations are all mass percentage concentrations.

[0068] Example 1

[0069] (CH3-0)3-Si-(CH2)3-NH-C(O)-N=N-C6H5 (Ⅰ-1)

[0070] A method for preparing an azosilane coupling agent of formula (I-1) comprises the following steps:

[0071] 1) 49.20 g of ethyl carbamate was dissolved in 150 g of triethylamine, and the reactor was placed under a nitrogen atmosphere; the temperature was raised to 55° C., 100 g of 3-chloropropyltrimethoxysilane was added dropwise to the reactor, and the reaction was carried out at a temperature of 55° C. to 60° C. for 1 h; after the reaction was completed, the by-product was filtered out, and the filtrate was distilled under reduced pressure at 60° C. and -0.090 MPa to recover triethylamine to obtain [3-(trimethoxysilyl)propyl]ethyl carbamate.

[0072] 2) All the [3-(trimethoxysilyl)propyl]urethane obtained in step 1) was added to a reactor, which was placed under a nitrogen atmosphere, and then 4 g of an ethanol solution of sodium ethoxide with a mass fraction of 25% was added, and then 189.95 g of an anhydrous toluene solution of phenylhydrazine with a mass fraction of 30% was added dropwise thereto, and the temperature was kept at 55° C. to 60° C. during the whole process, and the reaction was carried out at this temperature for 90 minutes after the dropwise addition; after the reaction was completed, the temperature was cooled to room temperature and 0.5 g of acetic acid was added to terminate the reaction, and then the crystallization was continuously stirred at room temperature, filtered, washed with isopropyl ether, and vacuum dried at 60° C. and a vacuum degree of 0.090 MPa to obtain 154.41 g of azosilane precursor.

[0073] 3) 154.41g of azosilane precursor and 4g of pyridine obtained in step 2) are dissolved in 300g of tetrahydrofuran, and then placed in a clean reactor, which is placed under a nitrogen atmosphere; 122.4g of a tetrahydrofuran solution of 60% dichloroisocyanuric acid (TCCA) is added dropwise to the reactor at 25°C, and reacted at room temperature for 45min. After the reaction is completed, the organic solvent is recovered by vacuum rotary drying at 60°C and a vacuum degree of 0.09MPa, and the residual paste is washed with a mixture of heptane and isopropyl ether (volume ratio of 1:1) and filtered. The filtrate is vacuum rotary evaporated at 60°C and a vacuum degree of 0.09MPa to remove the detergent to obtain the final azosilane coupling agent product.

[0074] Example 2

[0075] An azosilane coupling agent of formula (I-1) was prepared according to the method of Example 1, except that in step (1), "49.20 g of ethyl carbamate was dissolved in 150 g of triethylamine" was replaced by "53.67 g of ethyl carbamate was dissolved in 150 g of triethylamine".

[0076] Example 3

[0077] An azosilane coupling agent of formula (I-1) was prepared according to the method of Example 1, except that in step (2), "then 189.95 g of a 30% by mass solution of phenylhydrazine in anhydrous toluene was added dropwise" was replaced by "then 198.99 g of a 30% by mass solution of phenylhydrazine in anhydrous toluene was added dropwise".

[0078] Example 4

[0079] An azosilane coupling agent of formula (I-1) was prepared according to the method of Example 1, except that: in step (2), "after the reaction is completed, the temperature is cooled to room temperature and 0.5 g of acetic acid is added to terminate the reaction" is replaced by "after the reaction is completed, the temperature is cooled to room temperature and 2.5 g of acetic acid is added to terminate the reaction".

[0080] Example 5

[0081] An azosilane coupling agent of formula (I-1) was prepared according to the method of Example 1, except that in step (2), "the temperature is maintained at 55°C to 60°C during the entire process" was replaced by "the temperature is maintained at 60°C to 65°C during the entire process".

[0082] Example 6

[0083] An azosilane coupling agent of formula (I-1) was prepared according to the method of Example 1, except that: in step (3), "154.41 g of the azosilane precursor obtained in step 2) and 4 g of pyridine were dissolved in 300 g of tetrahydrofuran" was replaced by "the azosilane precursor obtained in step 2) and 4 g of triethylamine recovered in step 1) were dissolved in 300 g of tetrahydrofuran".

[0084] Example 7

[0085] The azosilane coupling agent of formula (I-1) was prepared according to the method of Example 1, except that: in step (3), "122.4 g of a 60% by mass solution of dichloroisocyanuric acid (TCCA) in tetrahydrofuran was added dropwise to the reactor at 25°C" was replaced by "32.61 g of solid sodium bromide was added to the reactor at 25°C, and chlorine gas was continuously bubbled into the bottom of the reactor to keep the pressure in the reactor below 0.1 MPa".

[0086] Example 8

[0087] The azosilane coupling agent of formula (I-1) was prepared according to the method of Example 1, except that: in step (3), "154.41 g of the azosilane precursor obtained in step 2) and 4 g of pyridine were dissolved in 300 g of tetrahydrofuran, and then placed in a clean reactor, and the reactor was placed in a nitrogen atmosphere; 122.4 g of a 60% by mass solution of dichloroisocyanuric acid (TCCA) in tetrahydrofuran was added dropwise to the reactor at 25°C, and the mixture was reacted at room temperature for 45 min." was replaced by "The azosilane precursor obtained in step 2) was dissolved in 300 g of tetrahydrofuran, and then placed in a clean reactor, and the reactor was placed in a nitrogen atmosphere; 169.90 g of a 60% by mass solution of diacetoxyphenyliodide (PIDA) in tetrahydrofuran was added dropwise to the reactor at 25°C, and the mixture was reacted at room temperature for 45 min.".

[0088] Example 9

[0089] The azosilane coupling agent of formula (I-1) was prepared according to the method of Example 1, except that: in step (3), "154.41 g of the azosilane precursor obtained in step 2) and 4 g of pyridine were dissolved in 300 g of tetrahydrofuran, and then placed in a clean reactor under a nitrogen atmosphere; 122.4 g of a 60% by mass solution of dichloroisocyanuric acid (TCCA) in tetrahydrofuran was added dropwise to the reactor at 25°C, and the mixture was reacted at room temperature for 45 min." was replaced by "The azosilane precursor obtained in step 2) was dissolved in 300 g of tetrahydrofuran, and then placed in a clean reactor under a nitrogen atmosphere; 226.88 g of a 60% by mass solution of bis(trifluoroacetoxy)phenyliodoacetyl (PIFA) in tetrahydrofuran was added dropwise to the reactor at 25°C, and the mixture was reacted at room temperature for 45 min.".

[0090] Example 10

[0091] (CH3-CH2-0)3-Si-(CH2)3-NH-C(O)-N=NC(O)-CH2-O-CH3 (Ⅰ-2)

[0092] The azosilane coupling agent of formula (I-2) was synthesized according to the method of Example 1, except that: in step (1), "raising the temperature to 55°C and dropping 100g of 3-chloropropyltrimethoxysilane into the reaction kettle" was replaced by "raising the temperature to 55°C and dropping 121.11g of 3-chloropropyltriethoxysilane into the reaction kettle"; in step (2), "then dropping 189.95g of a 30% by mass solution of phenylhydrazine in anhydrous toluene" was replaced by "then dropping 182.91g of a 30% by mass solution of methoxyacetohydrazide in anhydrous toluene".

[0093] Comparative Example 1

[0094] An azosilane coupling agent of formula (I-1) was prepared according to the method of Example 1, except that: in step (2), "after the reaction is completed, the temperature is cooled to room temperature and 0.5 g of acetic acid is added to terminate the reaction, and then stirring and crystallizing are continued at room temperature" is replaced by "after the reaction is completed, the temperature is cooled to room temperature and stirring and crystallizing are continued at room temperature".

[0095] Comparative Example 2

[0096] An azosilane coupling agent of formula (I-1) was prepared according to the method of Example 1, except that: in step (3), "122.4 g of a 60% by mass solution of dichloroisocyanuric acid (TCCA) in tetrahydrofuran was added dropwise to the reaction kettle at 25°C" was replaced by "93.92 g of a 60% by mass solution of N-bromosuccinimide (NBS) in tetrahydrofuran was added dropwise to the reaction kettle at 25°C".

[0097] Comparative Example 3

[0098] The azosilane coupling agent of formula (I-1) was prepared according to the method of Comparative Example 2, except that: in step (3), "154.41 g of the azosilane precursor obtained in step 2) and 4 g of pyridine were dissolved in 300 g of tetrahydrofuran" was replaced by "the azosilane precursor obtained in step 2) and 4 g of pyridine were dissolved in 300 g of dichloromethane".

[0099] Comparative Example 4

[0100] The azosilane coupling agent of formula (I-1) was prepared according to the method of Example 1, except that in step 2), 25% ethanol solution of sodium ethoxide was not added.

[0101] The purity of the azosilane precursor and the final azosilane coupling agent obtained in the examples of the present invention and the comparative examples was detected by gas chromatography, and the yields of the two were calculated by the following formulas. The specific results are shown in Table 1.

[0102]

[0103] Table 1

[0104]

[0105]

[0106] The above embodiments are only used to help understand the method and core idea of ​​the present invention. It should be noted that, for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing an azosilane coupling agent, characterized in that include: In the first step, the amino ester of formula (II) NH2-C(O)-O-R5(Ⅱ) With chlorosilane of formula (III) (R1) x (R2) 3-x -Si-R3-Cl(Ⅲ) The reaction yields an aminoester silane of formula (IV): (R1) x (R2) 3-x -Si-R3-NH-C(O)-O-R5(Ⅳ); In the second step, the amino ester silane of formula (IV) and the hydrazine compound of formula (V) are reacted with each other. NH2-NH-R4(V) The azosilane coupling agent precursor of formula (VI) is obtained by reaction under the action of a catalyst: (R1) x (R2) 3-x -Si-R3-NH-C(O)-NH-NH-R4(Ⅵ); In the third step, the azosilane coupling agent precursor of formula (VI) is reacted with an oxidant to obtain an azosilane coupling agent of formula (I): (R1) x (R2) 3-x -Si-R3-NH-C(O)-N=N-R4 (Ⅰ); In formula (I), formula (II), formula (III), formula (IV), formula (V), and formula (VI), R1 is hydroxyl, C1-C 18 Alkyl, C1-C 18 Alkoxy, C5-C 18 Cycloalkyl, C6-C 18 The aromatic group; R2 is C1-C 18 Alkyl, C1-C 18 Alkoxy, C5-C 18 Cycloalkyl, C6-C 18 The aromatic group; R3 is C1-C 18 Alkylene, C6-C 18 arylene; R4 is C1-C 18 Alkyl, C1-C 18 Alkoxy, C5-C 18 Cycloalkyl, C6-C 18 The aromatic, acyl, and ester groups; R5 is C1-C 18 Alkyl, C5-C 18 Cycloalkyl, C6-C 18 The aromatic group; x is an integer from 1 to 3.

2. The preparation method according to claim 1, characterized in that: R1 is -OH, -CH3, -CH2CH3, -(CH2)2CH3, -(CH2)3CH3, -(CH2)5CH3, -(CH2) 10 CH3, -(CH2) 15 CH3, -(CH2) 17 CH3, -O-CH3, -O-CH2CH3, -O-(CH2)2CH3, -O-(CH2)5CH3, -O-(CH2) 10 CH3, -O-(CH2) 17 CH3, -C5H9, -C6H 11 , -C6H5, -CH2-C6H5, -C6H4-CH3; R2 is -CH3, -CH2CH3, -(CH2)2CH3, -(CH2)3CH3, -(CH2)5CH3, -(CH2) 10 CH3, -(CH2) 15 CH3, -(CH2) 17 CH3, -O-CH3, -O-CH2CH3, -O-(CH2)2CH3, -O-(CH2)5CH3, -O-(CH2) 10 CH3, -O-(CH2) 17 CH3, -C5H9, -C6H 11 , -C6H5, -CH2-C6H5, -C6H4-CH3; R3 is -CH2-, -CH2 CH2-, -CH2CH2CH2-, -(CH2)5-, -(CH2) 10 -、-(CH2) 15 -、 -(CH2) 18 -、-C6H4-、-CH2-C6H4-、-C6H4-CH2-; R4 is -CH3, -CH2CH3, -(CH2)2CH3, -(CH2)3CH3, -(CH2)5CH3, -(CH2) 10 CH3, <h2 style=";text-align:left;direction:ltr">-(CH2)<h2 style=";text-align:left;direction:ltr"> 15 <h2 style=";text-align:left;direction:ltr"> CH3、-(CH2)<h2 style=";text-align:left;direction:ltr"> 17 <h2 style=";text-align:left;direction:ltr"> CH3、-O-CH3、-O-CH2CH3、-O-(CH2)2CH3、-O-(CH2)5CH3、 -O-(CH2) 10 CH3、-O-(CH2) 17 CH3、-C5H9、-C6H 11 、-C6H5、-CH2-C6H5、-C6H4-CH3、-C(O)-CH3、 -C(O)-CH2CH3, -CH2-C(O)-CH3, -C(O)-O-CH3, -C(O)-O-CH2CH3, -CH2-C(O)-O-CH3, -C(O)-CH2-O-CH3; R5 is -CH3; -CH2CH3; -(CH2)2CH3; -(CH2)3CH3; -(CH2)5CH3; -(CH2) 10 CH3; -(CH2) 15 CH3;-(CH2) 17 CH3;-C5H9;-C6H 11 ;-C6H5;-CH2-C6H5;-C6H4-CH3。 3. The preparation method according to claim 1, characterized in that: in the first step, at least one of the following conditions is included: Condition 1: the molar ratio of the chlorosilane of formula (III) to the amino ester of formula (II) is 1: (1-1.2); Condition 2: the reaction is carried out in the presence of an organic solvent, and the organic solvent is preferably an organic amine, more preferably at least one of pyridine, triethylamine, N,N-dimethylaniline, and tri-n-butylamine; Condition 3, the reaction temperature is 40°C to 70°C; Condition 4: The reaction time is 30 min to 90 min.

4. The preparation method according to claim 1, characterized in that: in the second step, at least one of the following conditions is included: Condition 1: The molar ratio of the hydrazine compound of formula (V) to the chlorosilane of formula (III) is (0.9-1.1):1; Condition 2: The catalyst is an ethanol solution of sodium ethoxide with a mass fraction of 25% to 30%; The reaction is carried out in the presence of an organic solvent, wherein the organic solvent is preferably an aromatic hydrocarbon organic solvent, more preferably one or more of toluene, cumene, diisopropylbenzene, and benzene; Condition 3, the reaction temperature is 45°C to 65°C; Condition 4: The reaction time is 30 min to 120 min.

5. The preparation method according to claim 4, characterized in that: In the second step, the mass ratio of the ethanol solution of sodium ethoxide with a mass fraction of 25% to 30% to the hydrazine compound of formula (V) is (5% to 12%):

1.

6. The preparation method according to claim 1, characterized in that: in the third step, the oxidant is one of dichloroisocyanuric acid / acid binding agent oxidation system, sodium bromide / chlorine / acid binding agent oxidation system, diacetoxybenzyl iodide, and bis(trifluoroacetoxy)benzyl iodide.

7. The preparation method according to claim 6, characterized in that: in the third step, at least one of the following conditions is included: Condition 1: In the dichloroisocyanuric acid (TCCA) / acid-binding agent oxidation system, the molar ratio of dichloroisocyanuric acid to the hydrazine compound of formula (V) is (0.5-2.5):1, and the mass ratio of the acid-binding agent to the hydrazine compound of formula (V) is (5%-10%):1; Condition 2: In the sodium bromide / chlorine / acid-binding agent oxidation system, the molar ratio of sodium bromide to the hydrazine compound of formula (V) is (0.5-2.5):1, the mass ratio of the acid-binding agent to the hydrazine compound of formula (V) is (5%-10%):1, and the chlorine gas maintains the system pressure below 0.1 MPa; Condition 3: the molar ratio of diacetoxybenzene iodide to the hydrazine compound of formula (V) is (0.5-2.5):1; Condition 4: The molar ratio of bis(trifluoroacetoxy)benzene iodoacetyl to the hydrazine compound of formula (V) is (0.5-2.5):

1.

8. The preparation method according to claim 1, 6 or 7, characterized in that: in the third step, at least one of the following conditions is included: Condition 1: The reaction is carried out in the presence of an organic solvent, and the organic solvent is preferably one or more of dichloromethane, tetrahydrofuran, N,N-dimethylamide, acetonitrile, methyl tert-butyl ether, and diethyl ether; Condition 2: reaction temperature is 20°C to 35°C; Condition 3: The reaction time is 30 min to 60 min.

9. The preparation method according to claim 1, characterized in that: In the second step, after the reaction is completed, a quencher is added to terminate the reaction; preferably, the quencher is acetic acid, and the mass ratio of acetic acid to the hydrazine compound of formula (V) is (0.5% to 5%): 1; preferably, the temperature of the quenching reaction is 20°C to 30°C, and the time of the quenching reaction is 5min to 15min.

10. The preparation method according to any one of claims 1 to 9, characterized in that: In the first step, the second step and the third step, the reaction processes are all carried out under the protection of inert gas.

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