A hydrosilylation reaction catalyst and a method for producing the same

Abstract

The application relates to the technical field of silicone catalysis, and discloses a hydrosilylation reaction catalyst and a preparation method thereof. The catalyst is made of a platinum complex catalyst solution, maleic anhydride, triphenyl borate, tetraethyl orthosilicate, propylene carbonate and diethylene glycol dibutyl ether; the preparation method involves the steps of solvent dewatering, pre-assembly of an electronic relay adduct, active metal introduction and heat-induced aging. The application constructs an electron-deficient coordination center through a step-by-step process, lowers the electron cloud density of a platinum center by using the Lewis acid property of triphenyl borate, improves the high-temperature resistance of the catalyst by matching the solvent cage effect of propylene carbonate, and effectively inhibits the generation of platinum black; meanwhile, the solubilization bridging effect of diethylene glycol dibutyl ether is used to solve the compatibility problem of high-polarity components and non-polar silicone oil matrix, and the obtained catalyst has high activity, high regioselectivity and excellent long-term storage stability.

Description

Technical Field

[0001] This invention relates to the field of organosilicon catalysis technology, specifically to a hydrogen silaneation reaction catalyst and its preparation method. Background Technology

[0002] Hydrosilylation is a core method for constructing silicon-carbon bonds and is widely used in processes such as organosilicon monomer synthesis, silicone rubber crosslinking and curing, and the preparation of functional silanes. Among numerous catalytic systems, castor catalysts, represented by vinylsiloxane-platinum complexes, have become the mainstream choice for industrial applications due to their high room temperature activity and good compatibility with organosilicon systems. However, in actual industrial production scenarios involving high-temperature reactions or long-term storage, this catalyst system has revealed several inherent technical defects, limiting its further high-end applications.

[0003] Existing castor catalysts rely on vinylsiloxanes as ligands. These ligands exhibit relatively weak coordination with the central platinum metal, leading to thermodynamic instability. Under high-temperature reaction conditions, weakly coordinated ligands readily dissociate, exposing the bare zero-valent platinum atoms and causing irreversible collisional aggregation driven by Brownian motion, ultimately forming inactive platinum black precipitate. This thermal deactivation not only increases the consumption of the precious metal platinum but also causes the reaction to stall, impacting production efficiency. Although adding alkyne or alkenyl inhibitors such as maleic anhydride can delay activity to some extent, the inhibitory effect of a single ligand is significantly reduced at high temperatures due to decreased binding strength, making it difficult to meet the stringent requirements of high-temperature rapid curing processes for catalyst heat resistance and lifespan.

[0004] Furthermore, unmodified platinum catalytic centers often exhibit an electron-rich state and relatively low steric hindrance. In the catalytic reaction of long-chain α-olefins with hydrogen-containing siloxanes, this active center structure makes it difficult to effectively control the reaction pathway, easily initiating inward isomerization side reactions of the olefin double bonds. This leads to silylation of hydrogen bonds onto non-terminal carbon atoms, generating non-target products. This lack of regioselectivity directly reduces the yield and purity of the target β-addition product, thus affecting the physical properties of the final organosilicon material.

[0005] To address the aforementioned stability issues, existing technologies have attempted to introduce highly polar solvents or sterically hindered ligands to stabilize the platinum centers. However, organosilicon reaction systems are typically composed of nonpolar polysiloxanes. The introduction of highly polar components disrupts the solubility parameter matching between the catalyst and the matrix, leading to difficulties in catalyst dispersion in silicone oil and a high likelihood of phase separation, turbidity, and even the precipitation of effective components during storage. This contradiction between compatibility and stability makes it difficult for the catalyst to maintain high activity while simultaneously ensuring heat resistance and long-term dispersion stability in nonpolar matrices. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a hydrogenation silylation reaction catalyst and its preparation method, which solves the problems of easy agglomeration and deactivation of existing cassette catalysts at high temperatures, low regioselectivity, and poor compatibility between highly polar components and non-polar matrices.

[0007] To achieve the above objectives, the present invention provides the following technical solution:

[0008] In a first aspect, the present invention provides a catalyst for a hydrogenation silylation reaction, employing the following technical solution:

[0009] A hydrogenation silylation reaction catalyst, made from raw materials comprising the following parts by weight:

[0010] 10 to 15 parts of platinum complex catalyst solution;

[0011] Maleic anhydride 0.2 to 0.7 parts;

[0012] Triphenyl borate, 0.8 to 2.0 parts;

[0013] 0.2 to 0.7 parts of tetraethyl orthosilicate;

[0014] 10 to 25 parts of propylene carbonate;

[0015] 15 to 30 parts of diethylene glycol dibutyl ether.

[0016] By employing the above technical solution, this invention utilizes the synergistic effect of physical solvation and chemical electronic regulation to improve the heat resistance, storage stability, and regioselectivity of platinum catalysts. The specific synergistic mechanism is described below:

[0017] First, regarding the mechanism for improving thermal stability, this invention constructs an electron relay stabilizing system. Traditional maleic anhydride ligands exhibit reduced ability to suppress platinum activity at high temperatures, leading to platinum atoms easily detaching from the ligands and colliding and aggregating. This invention introduces triphenyl borate as a Lewis acid auxiliary. Through a stepwise pre-assembly process, the empty orbitals of boron atoms in triphenyl borate are used to coordinate with the lone pair electrons of the carbonyl oxygen atom in maleic anhydride, forming an electron-deficient maleic anhydride-boronate adduct. This adduct then coordinates with the zero-valent platinum center. Due to the electron-withdrawing effect of the boronate ester, it exerts an electron-inducing effect on the platinum center through the maleic anhydride framework, reducing the electron cloud density of the d orbitals of the platinum atoms and enhancing the back-bonding strength between the ligand and platinum. This reduction in electron density results in the platinum center exhibiting partial positron charge (Pt). δ+ This increases the reduction and aggregation of platinum atoms to form zero-valent platinum black (Pt). 0 The activation energy barrier of the active center is reduced, thereby maintaining the monodisperse state of the active center in a high-temperature environment.

[0018] Secondly, regarding the solvent effect and the mechanism for improving compatibility, this invention designs a composite system of a polar solvent and an amphiphilic solvent. Propylene carbonate has a high dielectric constant, enabling it to form a dense polar solvation layer around platinum complex molecules. This physical isolation layer hinders Brownian motion collisions between platinum complex molecules, suppressing physical aggregation. To address the poor miscibility between highly polar propylene carbonate and non-polar polysiloxane matrices, diethylene glycol dibutyl ether is introduced into the system. Diethylene glycol dibutyl ether molecules contain both lipophilic butyl segments and hydrophilic ether oxygen bonds. As an amphiphilic bridging solvent, it reduces the interfacial tension between the polar catalyst droplets and the non-polar matrix, achieving uniform dispersion of the catalyst in the silicone oil system and resolving the contradiction between high stability and high compatibility.

[0019] Furthermore, regarding the mechanism of enhanced regioselectivity, the electron-deficient platinum centers formed above increase steric hindrance and electronic effects, causing the silane-hydrogen bonds to tend to add to the terminal carbon atoms of the olefin double bond with less steric hindrance and higher electron cloud density during the hydrosilylation reaction. This increases the proportion of the target product β-addition product and suppresses the internal olefin isomerization side reaction.

[0020] Preferably, the catalyst is made from raw materials comprising the following parts by weight: 13.0 to 13.5 parts of platinum complex catalyst solution; 0.3 to 0.6 parts of maleic anhydride; 0.8 to 1.9 parts of triphenyl borate; 0.25 to 0.6 parts of tetraethyl orthosilicate; 12 to 24 parts of propylene carbonate; and 17 to 27 parts of diethylene glycol dibutyl ether.

[0021] By adopting the above technical solution and controlling the ratio of each component within the above range, the electronic regulating agent and ligand can achieve stoichiometric balance, avoid excessive precipitation of the agent affecting the appearance, and at the same time ensure the protection of the platinum center, thereby maximizing the heat resistance life of the catalyst.

[0022] Preferably, the molar ratio of maleic anhydride to triphenyl borate is 1:0.95 to 1.05, and the molar ratio of maleic anhydride to platinum atoms in the platinum complex catalyst solution is 15:1 to 30:1.

[0023] By employing the above-mentioned technical solution, controlling the molar ratio is crucial for constructing a uniform electron relay structure. When the molar ratio of maleic anhydride to triphenyl borate is close to 1:1, it facilitates the formation of a structurally simple Lewis acid-base adduct, avoiding interference from multiple coordinated or free species. This process mainly includes two stages: the first stage involves the combination of triphenyl borate and maleic anhydride to form an electron relay adduct; the second stage involves the combination of zero-valent platinum and the electron relay adduct to form an active-center coordination assembly. Under this stoichiometric ratio, the complex structure formed within the system is stable, exhibiting superior heat resistance and reaction selectivity.

[0024] Preferably, the platinum complex catalyst solution is a solution of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane-platinum complex in vinyl-terminated polydimethylsiloxane, wherein the mass fraction of platinum is 2000 ppm to 5000 ppm.

[0025] By adopting the above technical solution, this invention selects a cassiterite catalyst as the active source, which is essentially a zero-valent platinum (Pt) catalyst. 0 The complex formed by the α-vinylsiloxane and β-vinylsiloxane. Compared with high-valent platinum precursors such as chloroplatinic acid, this zero-valent platinum complex can directly participate in the catalytic cycle without in-situ reduction, and the vinyl silicone oil carrier endows it with excellent intrinsic compatibility with organosilicon reaction systems, avoiding safety hazards caused by solvent evaporation.

[0026] Preferably, the propylene carbonate is anhydrous and has a water content of less than 50 ppm; the diethylene glycol dibutyl ether serves as an amphiphilic bridging solvent to disperse the polar catalyst components and provide compatibility with the non-polar silicone oil matrix.

[0027] By employing the above technical solution, controlling the moisture content is to prevent the hydrolytic failure of triphenyl borate. Ethyl orthosilicate, as an in-situ chemical dehydrating agent, can react with trace amounts of residual moisture in the system to generate silanol and ethanol, thereby protecting the integrity of the borate ester structure. The amphiphilic structure of diethylene glycol dibutyl ether, as described above, serves as a solubilizer and bridge.

[0028] Preferably, the catalyst does not contain phosphorus-based or nitrogen-based ligands.

[0029] By adopting the above technical solution, phosphorus and nitrogen ligands are eliminated, avoiding potential catalyst poisoning or sulfidation inhibition problems caused by these ligands. The use of a closed-loop feedstock composition ensures the purity of the catalytic system, avoids side reactions caused by impurities, and guarantees consistent product quality.

[0030] Secondly, the present invention provides a method for preparing a hydrogenation silylation reaction catalyst, which adopts the following technical solution:

[0031] A method for preparing a catalyst for a hydrosilylation reaction includes the following steps:

[0032] S1. Under inert gas protection, propylene carbonate, diethylene glycol dibutyl ether and tetraethyl orthosilicate are mixed and stirred at 20-30℃ to remove water, thereby obtaining an anhydrous composite solvent system.

[0033] S2. Heat the system to 40-55℃, add maleic anhydride and triphenyl borate to the anhydrous composite solvent system, and stir at a constant temperature until the solid is completely dissolved and the solution is clear and transparent.

[0034] S3. Stop heating and cool the system to 20-30℃. Add the platinum complex catalyst solution dropwise while stirring. After the addition is complete, keep the temperature constant and continue stirring.

[0035] S4. Heat the system to 50-65℃ and age it at a constant temperature under sealed and light-proof conditions. Then cool and filter to obtain the hydrogen silanization reaction catalyst.

[0036] By adopting the above technical solution, this invention establishes a preparation process combining stepwise pre-assembly and in-situ dehydration. This process is crucial for constructing stable electron relay structures, avoiding coordination competition and structural disorder caused by traditional one-time mixing processes. The specific stepwise reaction mechanism is described below:

[0037] The first step is the chemical dehydration of the solvent system. Because the Lewis acid additive (triphenyl borate) introduced in subsequent steps is extremely sensitive to moisture, even trace amounts can cause it to hydrolyze and become ineffective. This process preferentially mixes tetraethyl orthosilicate with the solvent under an inert gas atmosphere. Utilizing the high reactivity of tetraethyl orthosilicate, it preferentially captures trace amounts of moisture from the solvent and the environment, converting it into harmless silanols and ethanol. This creates an absolutely anhydrous environment for subsequent reactions, ensuring the structural integrity of the active additive.

[0038] The second step is the thermally induced pre-assembly of the electron-relay adduct. This is the core innovative step of this preparation method. Before adding the platinum source, maleic anhydride and triphenyl borate are brought into full contact in a polar solvent by heating. Under these conditions, the boron atom in triphenyl borate, acting as a Lewis acid center, undergoes directional coordination with the oxygen atom on the carbonyl group of maleic anhydride, generating a stable boron-anhydride adduct. This step ensures that the ligand has undergone electronic modification before the platinum atom enters the system, preventing the platinum atom from directly binding with the unmodified maleic anhydride, thus guaranteeing the homogeneity of the final catalyst structure.

[0039] The third step involves the controlled introduction and coordination exchange of the active metal. A platinum complex solution is slowly added dropwise under low temperature and stirring conditions, allowing platinum atoms to undergo an ordered ligand exchange reaction with the pre-formed boron and anhydride adduct. The low temperature environment inhibits the reaction rate, preventing thermal aggregation of platinum atoms due to localized exothermic reactions; while the pre-assembled adduct, with its unique electronic effects, can smoothly replace the weak ligands in the original platinum complex, forming new active centers.

[0040] The fourth step is high-temperature aging and lattice stabilization. By aging at a higher temperature again, the rearrangement of the coordination structure and thermodynamic stability are promoted, metastable intermediates are eliminated, and the final catalyst solution reaches the lowest energy stable state at the microscopic level, thus possessing excellent aging resistance.

[0041] Preferably, in step S1, the stirring time is 30-60 minutes; the inert gas is nitrogen.

[0042] By adopting the above technical solution, sufficient stirring time ensures full contact and reaction between tetraethyl orthosilicate and water in the solvent, while the nitrogen atmosphere effectively isolates the re-intrusion of external moisture, providing a reliable anhydrous basis for the introduction of borate esters.

[0043] Preferably, in step S2, the constant temperature stirring time is 30-50 minutes, so that maleic anhydride and triphenyl borate complete Lewis acid-base coordination assembly.

[0044] By adopting the above technical solution, the specific temperature range and time control are to overcome the activation energy of the coordination reaction between borate ester and maleic anhydride, ensure that the two reach a chemical equilibrium state, form a sufficient amount of electron relay adduct, and avoid the presence of free triphenyl borate ester in the system due to incomplete reaction, which would affect the solubility and stability of the catalyst in silicone oil.

[0045] Preferably, step S3 is implemented as follows: the stirring speed is increased to 400-500 rpm, the constant pressure dripping device is used to control the dripping process for 10-20 minutes, and after the dripping is completed, the stirring is continued at 20-30℃ for 15-30 minutes, and then step S4 is performed, wherein the aging time of step S4 is 2.0-3.0 hours.

[0046] By adopting the above technical solution, since the stirring in steps S1 and S2 is mainly used to achieve liquid-liquid mixing and solid-liquid dissolution, the conventional stirring speed in this field is sufficient. However, when introducing the highly active platinum complex in step S3, a high stirring speed must be used. This combination of high-speed stirring and slow dropwise addition achieves uniformity at the microscopic mixing level. The high shear force rapidly disperses the dropwise platinum catalyst, avoiding the risk of agglomeration caused by excessively high local platinum concentration. The continuous stirring after dropwise addition and the subsequent long-term aging provide sufficient time for the sterically hindered ligands to adjust their configuration around the platinum center, which helps to form a dense solvation protective layer and a regular electronic coordination structure. This is a key process guarantee for the catalyst to obtain a long-lasting heat-resistant life.

[0047] This invention provides a catalyst for hydrogenation silylation reaction and its preparation method. It has the following beneficial effects:

[0048] 1. This invention utilizes the electron relay adduct formed by triphenyl borate and maleic anhydride, combined with a high dielectric constant solvent environment constructed by propylene carbonate. By leveraging the Lewis acid properties of triphenyl borate, the electron cloud density of the platinum active center is reduced, increasing the energy barrier for the reduction and aggregation of platinum atoms. Simultaneously, the physical isolation effect of the polar solvent hinders the aggregation of platinum colloids, thereby avoiding the problem of deactivation caused by the formation of platinum black at high temperatures, which is common in conventional catalysts, and extending the catalyst's lifespan.

[0049] 2. By constructing an electron-deficient platinum coordination center, this invention utilizes the synergistic regulation of steric hindrance and electronic effects to enable the silicon-hydrogen bond to tend to add to the terminal carbon atom of the olefin double bond, which has less steric hindrance and higher electron cloud density, during the hydrosilylation reaction. This regulation mechanism increases the proportion of β-addition products, reduces the generation of isomerization impurities, and helps to improve the purity of the final organosilicon product.

[0050] 3. This invention introduces diethylene glycol dibutyl ether into the solvent system, utilizing the lipophilic alkyl chain and hydrophilic ether oxygen bond in its molecular structure to reduce the interfacial tension between the propylene carbonate catalytic droplets and the polysiloxane matrix. This solvent system acts as a solubilizer, allowing the catalyst to be uniformly dispersed in the silicone oil system and maintain a uniform single-phase state during long-term storage, avoiding stratification or precipitation and ensuring the uniformity of curing during application. Detailed Implementation

[0051] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to comparative examples and test cases. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0052] Examples 1-3: Example 1

[0053] This embodiment provides a catalyst for hydrogenation silylation reaction, the preparation process of which includes the following steps:

[0054] (1) Solvent system pretreatment: In a dry reaction vessel equipped with a mechanical stirrer, reflux condenser and nitrogen protection interface, add 15 mL (i.e. 15 parts by weight) of anhydrous propylene carbonate and 30 mL (i.e. 30 parts by weight) of diethylene glycol dibutyl ether, mix evenly and then add 0.45 g (i.e. 0.45 parts by weight) of tetraethyl orthosilicate, stir for 40 minutes at 25°C under nitrogen protection to obtain an anhydrous composite solvent system.

[0055] (2) Pre-assembly of electron relay adduct: The temperature inside the reactor is raised to 48°C, and 0.44 g (i.e. 0.44 parts by weight) of maleic anhydride and 1.30 g (i.e. 1.30 parts by weight) of triphenyl borate are added to the above solvent system in sequence. The temperature is kept at 48°C and stirred for 40 minutes until the solid is completely dissolved and the solution is clear and transparent. At this time, the molar ratio of maleic anhydride to triphenyl borate is about 1:1.

[0056] (3) Introduction of active metal: Stop heating and let the system cool naturally to 25°C. Increase the stirring speed to 450 rpm and slowly add 13.30 g (i.e. 13.30 parts by weight) of a platinum complex catalyst solution with a platinum content of 3000 ppm using a constant pressure dropping funnel. The dropping process takes 15 minutes. After the dropping is completed, continue stirring at 25°C for 20 minutes. At this time, the molar ratio of maleic anhydride to platinum atoms is about 22:1.

[0057] (4) Thermal induced aging: The reaction system was heated to 58°C and aged at a constant temperature for 2.5 hours under sealed and light-proof conditions. Then it was naturally cooled to room temperature. The resulting liquid was filtered through a 0.22μm polytetrafluoroethylene filter membrane to obtain a finished hydrogen silanization reaction catalyst with a platinum content of about 680ppm. Example 2

[0058] This embodiment provides a catalyst for hydrogenation silylation reaction, the preparation process of which includes the following steps:

[0059] (1) Solvent system pretreatment: In a dry reaction vessel equipped with a mechanical stirrer, a reflux condenser and a nitrogen protection interface, add 20 mL (i.e. 20 parts by weight) of anhydrous propylene carbonate and 20 mL (i.e. 20 parts by weight) of diethylene glycol dibutyl ether, mix evenly and then add 0.25 g (i.e. 0.25 parts by weight) of tetraethyl orthosilicate, stir for 30 minutes at 20°C under nitrogen protection to obtain an anhydrous composite solvent system.

[0060] (2) Pre-assembly of electron relay adduct: The temperature inside the reactor is raised to 45°C, and 0.30 g (i.e. 0.30 parts by weight) of maleic anhydride and 0.84 g (i.e. 0.84 parts by weight) of triphenyl borate are added to the above solvent system in sequence. The temperature is kept at 45°C and stirred for 30 minutes until the solid is completely dissolved and the solution is clear and transparent. At this time, the molar ratio of maleic anhydride to triphenyl borate is about 1:0.95.

[0061] (3) Introduction of active metal: Stop heating and let the system cool naturally to 20°C. Increase the stirring speed to 400 rpm and slowly add 13.30 g (i.e. 13.30 parts by weight) of a platinum complex catalyst solution with a platinum content of 3000 ppm using a constant pressure dropping funnel. The dropping process takes 10 minutes. After the dropping is completed, continue stirring at 20°C for 15 minutes. At this time, the molar ratio of maleic anhydride to platinum atoms is about 15:1.

[0062] (4) Thermal induced aging: The reaction system was heated to 55°C and aged at a constant temperature for 2.0 hours under sealed and light-proof conditions. Then it was naturally cooled to room temperature. The resulting liquid was filtered through a 0.22μm polytetrafluoroethylene filter membrane to obtain a finished hydrogen silane reaction catalyst with a platinum content of about 750ppm. Example 3

[0063] This embodiment provides a catalyst for hydrogenation silylation reaction, the preparation process of which includes the following steps:

[0064] (1) Solvent system pretreatment: In a dry reaction vessel equipped with a mechanical stirrer, reflux condenser and nitrogen protection interface, add 10 mL (i.e. 10 parts by weight) of anhydrous propylene carbonate and 30 mL (i.e. 30 parts by weight) of diethylene glycol dibutyl ether, mix evenly and then add 0.60 g (i.e. 0.60 parts by weight) of tetraethyl orthosilicate, stir for 60 minutes at 25°C under nitrogen protection to obtain an anhydrous composite solvent system.

[0065] (2) Pre-assembly of electron relay adduct: The temperature inside the reactor is raised to 50°C, and 0.60 g (i.e. 0.60 parts by weight) of maleic anhydride and 1.86 g (i.e. 1.86 parts by weight) of triphenyl borate are added to the above solvent system in sequence. The temperature is kept constant at 50°C and stirred for 45 minutes until the solid is completely dissolved and the solution is clear and transparent. At this time, the molar ratio of maleic anhydride to triphenyl borate is about 1:1.05.

[0066] (3) Introduction of active metal: Stop heating and let the system cool naturally to 25°C. Increase the stirring speed to 500 rpm and slowly add 13.30 g (i.e. 13.30 parts by weight) of a platinum complex catalyst solution with a platinum content of 3000 ppm using a constant pressure dropping funnel. The dropping process takes 20 minutes. After the dropping is completed, continue stirring at 25°C for 30 minutes. At this time, the molar ratio of maleic anhydride to platinum atoms is about 30:1.

[0067] (4) Thermal induced aging: The reaction system was heated to 60°C and aged at a constant temperature for 3.0 hours under sealed and light-proof conditions. Then it was naturally cooled to room temperature. The resulting liquid was filtered through a 0.22μm polytetrafluoroethylene filter membrane to obtain a finished hydrogen silane reaction catalyst with a platinum content of about 650ppm.

[0068] Comparative Examples 1-6:

[0069] Comparative Example 1:

[0070] Compared with Example 1, the difference is that in step (2), triphenyl borate was not added, only maleic anhydride was added, and the amount of other raw materials and preparation steps were the same as in Example 1.

[0071] Comparative Example 2:

[0072] Compared with Example 1, the difference is that in step (1), xylene is used instead of propylene carbonate in an equal volume, that is, the solvent system becomes a mixture of xylene and diethylene glycol dibutyl ether, and the amount of other raw materials and preparation steps are the same as in Example 1.

[0073] Comparative Example 3:

[0074] Compared with Example 1, the difference is that the preparation process sequence is changed. Specifically, propylene carbonate, diethylene glycol dibutyl ether, tetraethyl orthosilicate, maleic anhydride, triphenyl borate and platinum complex catalyst solution are added to the reactor at one time, mixed evenly, and then heated directly to 58°C and stirred for 3.5 hours. The pre-assembly in step (2) and the step-by-step addition in step (3) are not performed. All other steps are the same.

[0075] Comparative Example 4:

[0076] Compared with Example 1, the difference is that in step (1), an equal volume of propylene carbonate is used instead of diethylene glycol dibutyl ether, that is, the solvent system is entirely propylene carbonate, and the amount of other raw materials and preparation steps are the same as in Example 1.

[0077] Comparative Example 5:

[0078] Compared with Example 1, the difference is that in step (1), tetraethyl orthosilicate was not added, and the solvent was not specially anhydrous. The amount of other raw materials and the preparation steps are the same as in Example 1.

[0079] Comparative Example 6:

[0080] Compared with Example 1, the difference is that triphenyl borate and tetraethyl orthosilicate were not added, and the solvent system was replaced with an equal volume of xylene (i.e., only a simple physical mixing of platinum complex catalyst and maleic anhydride in xylene). The other process parameters (such as stirring time and temperature) were performed as in Example 1.

[0081] Test Example 1-3:

[0082] Test Example 1: Accelerated Aging Test for High Temperature Heat Resistance

[0083] 20g of each of the catalyst composition samples prepared in Examples 1-3 and Comparative Examples 1-6 were placed in clean, dry 25mL borosilicate glass vials, filled with nitrogen, and then sealed with caps to eliminate interference from external oxygen and humidity on the test results.

[0084] The sealed sample bottles were placed simultaneously in a constant temperature drying oven set at 120°C, with a distance maintained between the sample bottles to ensure uniform heating. The accelerated thermal aging test was then started.

[0085] During the test, the appearance of the sample was visually inspected through the observation window every hour, and the changes in the state of the solution were recorded. When obvious black particles were observed to be suspended inside the solution, or the bottom was precipitated, or the whole solution was transformed into a colloidal turbid state, it was determined that the catalyst was deactivated (i.e., platinum black agglomeration occurred), and the cumulative heating time at this time was recorded as the heat resistance life data of the sample.

[0086] For samples that do not show significant changes at the observation point, continue heating until the above-mentioned inactivation phenomenon occurs, with a test cutoff time of 200 hours.

[0087] The test results are recorded in Table 1.

[0088] Table 1: Heat resistance life test data of various hydrogenation silylation catalysts at 120℃

[0089]

[0090] Conclusion Analysis:

[0091] According to the data in Table 1, the catalysts prepared in Examples 1-3 exhibit excellent thermal stability at a high temperature of 120°C, with a heat resistance life exceeding 140 hours, which is significantly higher than that of the conventional cassette catalyst system shown in Comparative Example 6 (5 hours). This indicates that the composite stable system constructed in this invention can effectively inhibit the aggregation and deactivation of platinum colloids under high temperature conditions.

[0092] Comparing the data from Example 1 (163 hours) and Comparative Example 2 (11 hours), it is evident that the catalyst's thermal lifetime decreases by orders of magnitude when the solvent system lacks propylene carbonate, a high-dielectric-constant polar component. This result confirms the importance of a polar solvent environment: in polar solvents, a dense solvation shell can form around the platinum complex, providing crucial physical isolation and hindering collisions between platinum atoms and the formation of metallic bonds; once replaced with a non-polar solvent (such as xylene), this physical barrier disappears, leading to rapid aggregation of active centers under high-temperature thermal motion.

[0093] Comparing the data from Example 1 and Comparative Example 1 (58 hours), it can be seen that in the absence of the electron-regulating agent (triphenyl borate), although a polar solvent environment still exists, the catalyst stability is still reduced. This indicates that simple physical isolation is insufficient to maintain long-term stability; electronic effects are equally crucial. The electron relay structure formed by triphenyl borate and the ligand can regulate the electron cloud density of the platinum center, making it electron-deficient. This state increases the energy barrier for the reduction and aggregation of platinum atoms, thereby improving heat resistance at the chemical level.

[0094] Comparative data from Example 1 and Comparative Example 3 (43 hours) show that the catalyst prepared using a one-time mixing and heating process for each component exhibits a significant decrease in thermal stability. This confirms the necessity of the stepwise pre-assembly process: if a stable boronic ester and maleic anhydride adduct is not formed beforehand, disordered competitive coordination easily occurs between the boronic ester, maleic anhydride, and platinum centers in the reaction system, making it impossible to effectively construct an ordered electron relay transport chain. This results in a loose complex structure that is difficult to withstand high-temperature environments.

[0095] Furthermore, data from Comparative Example 5 (67 hours) showed that, without the addition of a dehydrating agent and without rigorous dehydration, trace amounts of moisture in the system could lead to the hydrolysis of borate esters, disrupting the electron relay structure and thus shortening the catalyst lifetime. While Comparative Example 4 (94 hours) maintained good single-phase stability, the lack of a bridging effect from an amphiphilic solvent could lead to microphase separation at high temperatures, resulting in the disruption of the local polar environment and lower stability than Example 1. In summary, this invention improves the thermal stability of the catalyst through the synergistic effect of physical solvent cages and chemical electronic effects.

[0096] Test Example 2: Evaluation of the activity and regioselectivity of the hydrogenation silylation reaction

[0097] In a 100mL three-necked flask equipped with a magnetic stirrer, thermometer, and reflux condenser, add 11.2g (0.1mol) of 1-octene and 6.0g of polymethylhydrosiloxane (PMHS, active hydrogen content approximately 1.6%). At this point, the molar ratio of vinyl groups to silane bonds in the system is controlled at 1.1:1. High-purity nitrogen is introduced to purge the air in the flask three times, and then stirring is started under nitrogen protection.

[0098] The reaction system was heated to 80°C and kept at a constant temperature. The catalyst compositions prepared in Examples 1-3 and Comparative Examples 1-6 were taken into the reaction system using a microsyringe and added to the reaction system at a dosage of 10 ppm of platinum atoms relative to the mass of 1-octene. The addition time was recorded as the reaction start point.

[0099] Maintain a constant temperature of 80°C and stir the reaction for 4 hours. After the reaction is complete, immediately place the flask in an ice-water bath to cool to room temperature to terminate the reaction.

[0100] Take a small amount of the reaction mixture and perform a 1H NMR spectrum ( 1 ¹H-NMR analysis was performed using deuterated chloroform as solvent and tetramethylsilane as internal standard. The conversion rate was determined by integrating the remaining amount of silane-hydrogen bonds (Si-H, δ4.6-4.8ppm). β-selectivity was calculated by the integral area ratio of the terminal addition product (β-addition, Si-CH2-, δ0.5-0.6ppm) to the end-position addition product (α-addition, Si-CH(CH3)-, δ1.0-1.1ppm). The formation of internal olefin isomerization byproducts was monitored simultaneously.

[0101] The test results are recorded in Table 2.

[0102] Table 2: Performance data of the catalyst in the hydrosilylation reaction of 1-octene with PMHS

[0103]

[0104] Conclusion Analysis:

[0105] Based on the data analysis in Table 2, the catalysts prepared in Examples 1-3, while maintaining high catalytic activity (conversion rates all exceeding 96%), exhibited extremely high regioselectivity, with the β-addition ratio of the target product remaining stable at over 94.5%, and also suppressed olefin isomerization side reactions.

[0106] Comparing the data from Example 1 and Comparative Example 6, it can be seen that although the conventional unmodified castor catalyst has extremely high activity (conversion rate of 99.2%), its β-selectivity is only 72.5%, accompanied by a high rate of 15.2% of internal olefin isomerization byproducts. This indicates that the unregulated platinum active center is prone to initiating double bond migration or α-addition during catalysis. Example 1, by introducing an electronic regulation system, reduced the isomerization rate to 1.3%, confirming the catalyst's effective control over the reaction pathway.

[0107] Comparing the data differences between Example 1 (β-selectivity 96.2%) and Comparative Example 1 (β-selectivity 88.4%) directly confirms the core role of the electronic modifier triphenyl borate in improving regioselectivity. In Comparative Example 1, maleic anhydride was used alone as a ligand, which, while suppressing side reactions to some extent, had limited effect. In Example 1, however, triphenyl borate, as a Lewis acid, formed an adduct with maleic anhydride, further reducing the electron cloud density of maleic anhydride, and subsequently reducing the electron density of the platinum center through back-bonding π-bonding. This electron-deficient platinum center increases steric hindrance and electronic effects, making the silane-hydrogen bond more inclined to add to the terminal carbon atom with lower steric hindrance and higher electron cloud density, thereby increasing the proportion of anti-Markovnikov addition (β-addition).

[0108] Comparative data from Example 1 and Comparative Example 3 (β-selectivity 89.5%) show that the catalyst prepared using a one-step mixing process did not achieve optimal selectivity. This indicates that without a pre-assembly step, the borate ester cannot form a uniform and stable electron relay structure with maleic anhydride, resulting in the presence of platinum species in multiple coordination states in the system. Some platinum centers are not effectively electronically regulated, thus lowering the overall selectivity.

[0109] Furthermore, comparing the data from Example 1 with Comparative Examples 2 and 4 shows that the solvent environment also has a fine-tuning effect on selectivity. The polar and amphiphilic composite solvent system used in Example 1 may be more conducive to stabilizing the specific active intermediate configuration, or may affect the energy level of the reaction transition state through solvation, thereby helping to improve the regioselectivity of the product while ensuring high activity. Comparative Example 5, due to inadequate dehydration leading to partial hydrolysis and failure of the borate ester, showed data close to that of Comparative Example 1 without borate ester, further demonstrating the necessity of maintaining the integrity of the auxiliary agent structure.

[0110] Test Example 3: Compatibility and Storage Stability Test of Catalyst in Silicon Oil System

[0111] Measure 50g of vinyl-terminated polydimethylsiloxane (viscosity 500cSt, vinyl content 0.45%) and place it in a 100mL clean, dry glass beaker as a dispersion matrix.

[0112] Using a micropipette, 0.5 g of the catalyst compositions prepared in Examples 1-3 and Comparative Examples 1-6 were respectively added dropwise to the above-mentioned silicone oil, and mechanically stirred at 300 rpm for 5 minutes at room temperature of 25°C to ensure that the catalyst was fully dispersed in the silicone oil.

[0113] After stirring, immediately observe the appearance of the mixture under strong flashlight illumination, record its initial transparency and whether there are oil droplets suspended or phase separation; then transfer each sample to a sealed glass bottle and store it in a light-protected environment at 25°C for 30 days.

[0114] After the storage period, the appearance of each sample was observed again to check for turbidity, precipitation, or stratification, in order to assess the long-term compatibility and stability of the catalyst and the silicone oil matrix.

[0115] The test results are recorded in Table 3.

[0116] Table 3: Compatibility and long-term storage stability of the catalyst in vinyl silicone oil

[0117]

[0118] Conclusion Analysis:

[0119] According to the data in Table 3, the hydrogenation silylation catalysts prepared in Examples 1-3 exhibited excellent initial solubility and long-term storage stability in vinyl silicone oil, maintaining a clear, transparent, and homogeneous single-phase state even after 30 days of storage. This result verifies the rationality of the composite solvent system design in this invention, especially the successful introduction of the amphiphilic bridging solvent in solving the interfacial tension problem between the highly polar component and the non-polar silicone oil matrix.

[0120] Comparing the experimental phenomena of Example 1 and Comparative Example 4 (severe stratification) clearly reveals the crucial role of the amphiphilic bridging solvent (diethylene glycol dibutyl ether). In Comparative Example 4, only propylene carbonate was used as the solvent. Due to the extremely high dielectric constant and polarity of propylene carbonate, its solubility parameters differ greatly from those of the non-polar polydimethylsiloxane, resulting in the catalyst failing to disperse after addition, rapidly undergoing phase separation and settling to the bottom. This phase separation can lead to excessively high or low local catalyst concentrations in practical applications, severely affecting the uniformity of curing. In contrast, Example 1 introduced diethylene glycol dibutyl ether with an ether bond structure. Utilizing the lipophilic alkyl chain and hydrophilic ether oxygen bond in its molecular structure, it acts as a solubilizing bridge between propylene carbonate and silicone oil, achieving nanoscale dispersion of polar catalyst droplets in non-polar silicone oil.

[0121] The comparison between Example 1 and Comparative Example 3 (microemulsification, followed by crystallization) indicates that the preparation process directly affects the final morphology of the product. When a one-time mixing process was used, the triphenyl borate failed to form a stable adduct with maleic anhydride under high-concentration polar conditions. This resulted in some free triphenyl borate or borate gradually precipitating out after dilution in silicone oil due to changes in solubility, manifesting as needle-like crystals after storage. This demonstrates that the stepwise pre-assembly process not only affects heat resistance but also the physical stability of the catalyst within the matrix.

[0122] Furthermore, although Comparative Example 2 (xylene system) and Comparative Example 6 (conventional system) also performed well in the compatibility test (clear and transparent), considering the heat resistance data of Test Example 1, they could not simultaneously guarantee heat resistance stability. Comparative Example 2 achieved compatibility by relying on xylene, but sacrificed the thermal protection provided by the polar solvent cage; while Example 1 of the present invention, while retaining propylene carbonate (which provides thermal stability), overcomes its incompatibility shortcomings through compounding technology, thereby simultaneously achieving the dual technical indicators of high temperature resistance and easy dispersibility, which is a comprehensive performance that a single solvent system cannot achieve.

Claims

1. A catalyst for hydrogenation silylation reaction, characterized in that, Made from the following ingredients in parts by weight: 10-15 parts of platinum complex catalyst solution; Maleic anhydride 0.2-0.7 parts; Triphenyl borate 0.8-2.0 parts; 0.2-0.7 parts of tetraethyl orthosilicate; 10-25 parts of propylene carbonate; 15-30 parts of diethylene glycol dibutyl ether; The molar ratio of maleic anhydride to triphenyl borate is 1:0.95-1.05, and the molar ratio of maleic anhydride to platinum atoms in the platinum complex catalyst solution is 15:1-30:

1. The propylene carbonate is anhydrous and has a water content of less than 50 ppm; the diethylene glycol dibutyl ether serves as an amphiphilic bridging solvent to disperse the polar catalyst components and provide compatibility with the non-polar silicone oil matrix. The preparation method of the hydrogenation silylation reaction catalyst includes the following steps: S1. Under inert gas protection, propylene carbonate, diethylene glycol dibutyl ether and tetraethyl orthosilicate are mixed and stirred at 20-30℃ to remove water, thereby obtaining an anhydrous composite solvent system. S2. Heat the system to 40-55℃, add maleic anhydride and triphenyl borate to the anhydrous composite solvent system, and stir at a constant temperature until the solid is completely dissolved and the solution is clear and transparent. S3. Stop heating and cool the system to 20-30℃. Add the platinum complex catalyst solution dropwise while stirring. After the addition is complete, keep the temperature constant and continue stirring. S4. Heat the system to 50-65℃ and age it at a constant temperature under sealed and light-proof conditions. Then cool and filter to obtain the hydrogen silanization reaction catalyst.

2. The hydrogenation silylation reaction catalyst according to claim 1, characterized in that, Made from the following ingredients in parts by weight: 13.0-13.5 parts of platinum complex catalyst solution; Maleic anhydride 0.3-0.6 parts; Triphenyl borate 0.8-1.9 parts; 0.25-0.6 parts of tetraethyl orthosilicate; 12-24 parts of propylene carbonate; 17-27 parts of diethylene glycol dibutyl ether.

3. The hydrogenation silylation reaction catalyst according to claim 1, characterized in that, The platinum complex catalyst solution is a solution of 1,3-divinyl-1,1,3,3-tetramethyldisiloxane-platinum complex in vinyl-terminated polydimethylsiloxane, wherein the mass fraction of platinum is 2000-5000 ppm.

4. The hydrogenation silylation reaction catalyst according to claim 1, characterized in that, The hydrogenation silylation catalyst does not contain phosphorus-based or nitrogen-based ligands.

5. A method for preparing a catalyst for a hydrosilylation reaction, characterized in that, The preparation of a hydrogenation silylation reaction catalyst as described in any one of claims 1-4 comprises the following steps: S1. Under inert gas protection, propylene carbonate, diethylene glycol dibutyl ether and tetraethyl orthosilicate are mixed and stirred at 20-30℃ to remove water, thereby obtaining an anhydrous composite solvent system. S2. Heat the system to 40-55℃, add maleic anhydride and triphenyl borate to the anhydrous composite solvent system, and stir at a constant temperature until the solid is completely dissolved and the solution is clear and transparent. S3. Stop heating and cool the system to 20-30℃. Add the platinum complex catalyst solution dropwise while stirring. After the addition is complete, keep the temperature constant and continue stirring. S4. Heat the system to 50-65℃ and age it at a constant temperature under sealed and light-proof conditions. Then cool and filter to obtain the hydrogen silanization reaction catalyst.

6. The method for preparing a hydrogenation silylation reaction catalyst according to claim 5, characterized in that, In step S1, the stirring time is 30-60 minutes; the inert gas is nitrogen.

7. The method for preparing a hydrogenation silylation reaction catalyst according to claim 5, characterized in that, In step S2, the constant temperature stirring time is 30-50 minutes, so that maleic anhydride and triphenyl borate can complete Lewis acid-base coordination assembly.

8. The method for preparing a hydrogenation silylation reaction catalyst according to claim 5, characterized in that, The specific implementation method of step S3 is as follows: Increase the stirring speed to 400-500 rpm, use a constant pressure dripping device to control the dripping process for 10-20 minutes, and continue stirring at 20-30℃ for 15-30 minutes after the dripping is completed, and then proceed to step S4, where the aging time of step S4 is 2.0-3.0 hours.

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