A process for the preparation of a hydrocarbylchlorosilane

Abstract

The application discloses a preparation method of hydrocarbon chlorosilane, and the preparation method comprises the following steps: carrying out a silicon-hydrogen addition reaction on 1-olefin and chlorosilane under the catalysis of a platinum catalyst to obtain hydrocarbon chlorosilane; wherein the 1-olefin is C3-C 20 The olefin is C3-C7, and the chlorosilane is hydrogen-containing chlorosilane; the temperature of the silicon-hydrogen addition reaction is 10-40 DEG C, and the pressure is normal pressure. The preparation method of the hydrocarbon chlorosilane can effectively simplify the preparation process of the hydrocarbon chlorosilane, improve the safety and the product quality.

Description

Technical Field

[0001] This invention relates to the field of organic synthesis technology, and in particular to a method for preparing a hydrocarbon-based chlorosilane. Background Technology

[0002] Chlorosilanes and their derivatives are important organic synthesis intermediates with wide applications in conductive polymer materials, new energy, and coatings. Specifically, in the synthesis of organosilicon, they can effectively protect the hydroxyl groups in organosilicon. At the same time, when long-chain alkyl chlorosilanes are linked to the hydroxyl groups on the side chains of polymer materials, they can effectively improve the flexibility, hydrophobicity, and solubility of the molecular materials in organic solvents.

[0003] Hydrochlorosilanes are derivatives of chlorosilanes, and their primary synthetic method is the hydrosilylation reaction of alkenes and hydrochlorosilanes. Typically, this hydrosilylation reaction is catalyzed by highly reactive chloroplatinic acid, resulting in a vigorous reaction that releases a large amount of heat. Therefore, even with high-pressure vessels, significant temperature and pressure surges can occur, posing significant safety hazards during production. To address these issues, some researchers have added a certain amount of solvent to the hydrosilylation reaction system to prevent a rapid rise in reaction temperature (the solvent absorbs some heat). However, the use of solvent not only reduces production efficiency and increases costs, but also requires large-scale post-processing, placing a burden on both the economy and the environment. To address the temperature and pressure surge problems, some researchers have attempted to adjust the order or rate of reactant addition, which can suppress rapid temperature rises and catalyst poisoning to some extent; however, this reduces the controllability of the types and amounts of byproducts.

[0004] In addition, existing hydrosilylation reactions usually require catalyst pretreatment and strict control of temperature and pressure during the process, which has disadvantages such as cumbersome operation and complicated preparation methods; most importantly, the yield and purity of the obtained products are low.

[0005] In summary, existing methods for preparing hydrocarbon-based chlorosilanes have drawbacks such as poor safety, complex operation, and poor product quality. Summary of the Invention

[0006] This invention aims to at least solve one of the technical problems existing in the prior art. To this end, this invention proposes a method for preparing hydrocarbon-based chlorosilanes, which can effectively simplify the preparation process of hydrocarbon-based chlorosilanes, improve safety and product quality.

[0007] According to a first aspect of the present invention, a method for preparing a hydrocarbon chlorosilane is provided, the method comprising performing a hydrosilylation reaction of a compound of formula I and a compound of formula II under the catalysis of a platinum catalyst to obtain a hydrocarbon chlorosilane of formula III;

[0008]

[0009] in:

[0010] In Equation I, R1 is C4~C 18 alkyl;

[0011] In Formula II, R2 and R3 are independently selected from C1 to C3 alkyl groups;

[0012] The molar ratio of the compound shown in Formula I to the compound shown in Formula II is 1:3.5 to 4;

[0013] The conditions for the hydrosilylation are room temperature and normal pressure; the room temperature is 10–40°C.

[0014] The preparation method according to embodiments of the present invention has at least the following beneficial effects:

[0015] (1) Traditional technology believes that high temperature or low temperature will promote side reaction and inhibit main reaction in hydrosilylation reaction. Therefore, in traditional preparation methods, the temperature of hydrosilylation reaction is usually controlled between 50 and 180°C to improve the yield of product.

[0016] Traditional techniques have also shown that, between 50 and 180°C, bound water in platinum catalysts can trigger serious side reactions. Therefore, the platinum catalyst must be purified and activated during the hydrosilylation reaction.

[0017] Furthermore, since the compounds shown in Formula II (chlorosilanes) typically have low boiling points, heating them for hydrosilylation reactions may require the use of high-pressure, sealed reaction vessels, or may cause chlorosilanes to escape into the environment, which could pose safety hazards.

[0018] This invention limits the temperature of the hydrosilylation reaction, preventing the chlorosilane from evaporating violently during the reaction. Therefore, even without sealing or pressurization, it does not cause serious air pollution, ultimately simplifying the preparation process and improving safety. Furthermore, due to the reduced hydrosilylation reaction temperature and the limitation on the types and amounts of raw materials, the side reactions that water in the platinum catalyst can initiate are significantly reduced. Therefore, the pretreatment process for the platinum catalyst can be omitted, reducing the limitations of the preparation method and making it more suitable for industrial applications. Most importantly, this invention also demonstrates that the product yield can reach almost 100% at room temperature.

[0019] (2) In order to provide a liquid reaction environment and to suppress the sharp rise in temperature during the hydrosilylation reaction, a solvent is usually added to the reaction system in the traditional technology.

[0020] By limiting the selection of substituents in the compound shown in Formula II, this invention makes the chlorosilane shown in Formula II liquid at room temperature, thus enabling it to also function as a solvent. Therefore, the preparation method of this invention omits the use of solvent, saving costs and the subsequent solvent recovery and treatment process.

[0021] (3) In the system obtained by hydrosilylation reaction, in addition to the hydrocarbon chlorosilane shown in Formula III, there are also unreacted reactants and catalysts. Recrystallization or distillation is usually used to remove impurities. However, the boiling point of the compound shown in Formula I is high and close to that of the product, so it is difficult to remove by distillation. On the other hand, the product is highly sensitive to water, and it is inevitable to come into contact with air during recrystallization, which may affect the yield and purity. Therefore, the purification effect of recrystallization is usually not ideal.

[0022] This invention achieves a complete reaction of the compound shown in Formula I by adjusting the molar ratio of the compound shown in Formula II to the compound shown in Formula II. Therefore, the system obtained from the hydrosilylation reaction contains almost no compound shown in Formula I. Furthermore, since the boiling points of the compound shown in Formula II and the product are significantly different, impurities can be removed by a simple distillation method.

[0023] In other words, the present invention simplifies the impurity removal process of the product by selecting the types and proportions of raw materials.

[0024] (4) In summary, by limiting the types and amounts of raw materials used, this invention not only simplifies the preparation method and reduces safety hazards, but also overcomes the biases in traditional technology. Under room temperature (i.e., 10 to 40°C) conditions, it achieves a product yield of ≥99% (hydrochlorosilanes shown in Formula III) and a product purity of ≥97%, thus achieving unexpected technical effects.

[0025] According to some embodiments of the present invention, R1 in Formula I and R2 and R3 in Formula II may be the same, two of them may be the same, or all three may be different.

[0026] According to some embodiments of the present invention, in formula I, R1 is C 15 ~C 16 alkyl.

[0027] According to some preferred embodiments of the present invention, in formula I, R1 is C 16 alkyl.

[0028] According to some further preferred embodiments of the present invention, the compound shown in Formula I is selected from 1-octadecane (CAS: 112-88-9).

[0029] Therefore, terminal olefins, compared to intermediate olefins, can reduce steric hindrance, ultimately reducing the difficulty of the hydrosilylation reaction.

[0030] According to some embodiments of the present invention, in Formula II, R2 and R3 are independently selected from C1 or C2 alkyl groups.

[0031] According to some embodiments of the present invention, the compound represented by Formula II represents at least one of dimethylchlorosilane (CAS: 1066-35-9), diethylchlorosilane (CAS: 1609-19-4), and methylethylchlorosilane (CAS: 6374-21-6).

[0032] According to some preferred embodiments of the present invention, the compound represented by Formula II represents at least one of dimethylchlorosilane and methylethylchlorosilane.

[0033] Therefore, the compound shown in Formula II has a low melting point and can be used as a solvent at room temperature. At the same time, the compound shown in Formula II also has a low boiling point, so any unreacted chlorosilane compound can be separated from the hydrocarbon chlorosilane shown in Formula III by simple distillation, simplifying the product purification process.

[0034] According to some embodiments of the present invention, the molar ratio of the compound shown in Formula I to the compound shown in Formula II is approximately 1:4.

[0035] This ensures that the compound shown in Formula I reacts completely, and the mixture obtained from the hydrosilylation reaction contains almost no compound shown in Formula I, ultimately simplifying the product purification process. Simultaneously, the excess compound shown in Formula II competes with the platinum catalyst for reaction with the compound shown in Formula I, suppressing side reactions caused by the platinum catalyst (containing water of crystallization).

[0036] According to some embodiments of the present invention, the platinum catalyst comprises at least one of anhydrous chloroplatinic acid (CAS: 16941-12-1) and chloroplatinic acid containing crystallization water (CAS: 16941-12-1).

[0037] Although the water of crystallization in the platinum catalyst can react with the compound shown in Formula I (side reaction) and also promote side reactions in the product (hydrochlorosilane shown in Formula III), the present invention limits the temperature, and the above-mentioned side reactions are suppressed. Therefore, whether the platinum catalyst used in the present invention contains water of crystallization has almost no effect on the yield and purity of the product of the preparation method.

[0038] According to some embodiments of the present invention, the chloroplatinic acid containing crystallization water includes chloroplatinic acid hexahydrate.

[0039] According to some preferred embodiments of the present invention, the platinum catalyst is selected from anhydrous chloroplatinic acid.

[0040] According to some embodiments of the present invention, the molar ratio of the compound shown in Formula I to the platinum catalyst is 55,000 to 3,500,000:1.

[0041] The above ratios affect the rate of the hydrosilylation reaction to some extent:

[0042] When the above ratio is equal to 3,000,000:1, the hydrosilylation reaction can be completed within 24 hours;

[0043] When the above ratio is greater than 3,000,000:1, the hydrosilylation reaction can still proceed, but the time required is longer, for example, about 32 hours or 30 hours.

[0044] When the ratio is less than 3,000,000:1, the time required for the hydrosilylation reaction is greatly shortened, for example, it can be about 18 hours.

[0045] However, the amount of platinum catalyst added does not affect the yield and purity of the product obtained by the preparation method.

[0046] According to some preferred embodiments of the present invention, the molar ratio of the compound shown in Formula I to the platinum catalyst is 3,000,000 to 3,050,000:1.

[0047] According to some preferred embodiments of the present invention, the molar ratio of the compound shown in Formula I to the platinum catalyst is 59,000 to 60,000:1.

[0048] According to some embodiments of the present invention, the temperature of the hydrosilylation reaction is 10–30°C.

[0049] According to some embodiments of the present invention, the hydrosilylation reaction is carried out under water bath conditions; the water bath is not temperature controlled.

[0050] Therefore, although the water bath temperature is the same as room temperature at the beginning of the hydrosilylation reaction, the water bath can remove the heat generated by the hydrosilylation reaction to a certain extent, so that the temperature of the hydrosilylation reaction is maintained at a relatively constant level, effectively suppressing the escape of the compound shown in Formula II, and reducing the promotion of side reactions by temperature surge.

[0051] According to some embodiments of the present invention, the atmospheric pressure is approximately one standard atmosphere, or about 0.1 MPa. This pressure may vary slightly depending on the location where the preparation method is carried out, but such variations will not affect the implementation of the preparation method or the corresponding results.

[0052] According to some embodiments of the present invention, the order of material addition for the hydrosilylation reaction is as follows: the compound represented by Formula II, the platinum catalyst, and the compound represented by Formula I are added to the reaction vessel in sequence.

[0053] Therefore, the reaction between the water of crystallization in the platinum catalyst and the compound shown in Formula I can be effectively avoided, that is, side reactions can be effectively avoided, the main reaction can be promoted, and the yield of the compound shown in Formula III can be increased.

[0054] According to some embodiments of the present invention, the preparation method further includes purifying the hydrocarbon chlorosilane of formula III after the hydrosilylation reaction.

[0055] According to some embodiments of the present invention, the purification includes sequential atmospheric distillation and rotary evaporation.

[0056] According to some embodiments of the invention, the temperature of the atmospheric distillation is greater than the boiling point of the compound represented by Formula II. This allows unreacted components of the compound represented by Formula II to be removed from the system.

[0057] According to some embodiments of the present invention, the temperature difference between the atmospheric distillation and the boiling point of the compound represented by Formula II is ≤10°C. Therefore, side reactions can be suppressed as much as possible during atmospheric distillation.

[0058] According to some embodiments of the present invention, the atmospheric distillation is carried out under water-resistant conditions. This avoids the formation of byproducts from the reaction of the hydrocarbon chlorosilane shown in Formula III with water.

[0059] According to some embodiments of the present invention, the atmospheric distillation further includes collecting the distilled compound represented by Formula II;

[0060] Furthermore, the yield of the compound shown in Formula II is ≥68%, for example, it could be 68.5% or 71.3%. Here, yield refers to the ratio of the mass of the recovered substance to the mass of the feed.

[0061] According to some embodiments of the present invention, the rotary evaporation temperature is 10-20°C higher than the boiling point of the compound shown in Formula II; thereby, the separation and removal of the compound shown in Formula II can be further achieved.

[0062] According to some embodiments of the present invention, the impurity removal further includes solid-liquid separation after the suspension evaporation; the obtained solid is the platinum catalyst, and the obtained liquid is purified hydrocarbon chlorosilane.

[0063] The platinum catalyst obtained from the solid-liquid separation can be reused 3 to 5 times without affecting the yield of the hydrocarbon chlorosilane; however, the time required for the hydrosilylation reaction increases with the number of reuses. The reason for this phenomenon is that the proportion of active components in the platinum catalyst gradually decreases (i.e., partial poisoning) as the number of reuses increases.

[0064] According to some embodiments of the present invention, in the preparation method, the yield of the hydrocarbon chlorosilane shown in Formula III is ≥99%. This indicates that the hydrosilylation reaction is almost proportional, the compound shown in Formula I reacts almost completely, and the purification process results in almost no loss of the hydrocarbon chlorosilane.

[0065] According to some embodiments of the present invention, in the preparation method, the purity of the hydrocarbon chlorosilane shown in Formula III is ≥97%.

[0066] Therefore, it can be seen that the preparation method did not cause serious side reactions due to the decrease in temperature or the presence of water of crystallization in the platinum catalyst, and the purification effect was good.

[0067] On the other hand, it is also known that if the purification process is further optimized, the purity of the obtained hydrocarbon chlorosilanes may be further improved.

[0068] Unless otherwise specified, “about” in this invention means that the allowable error is within ±2%. For example, about 100 means 100 ± 2% × 100.

[0069] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Detailed Implementation

[0070] The following will describe the concept and technical effects of the present invention clearly and completely with reference to embodiments, so as to fully understand the purpose, features and effects of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are all within the scope of protection of the present invention.

[0071] Unless otherwise specified, the yield in this invention is the ratio between the actual value and the theoretical value of the corresponding substance; the purity is the ratio of the mass of the target product to the total mass of the system containing the target product.

[0072] Example 1

[0073] In this embodiment, an octadecyldimethylchlorosilane was prepared, and the specific reaction formula is as follows:

[0074]

[0075] The specific reaction process is as follows:

[0076] S1. Under magnetic stirring in a water bath (room temperature approximately 25°C), dimethylchlorosilane (378.44 g, 4 mol), chloroplatinic acid hexahydrate (0.173 mg, 0.00033 mmol), and 1-octadecane (252.49 g, 1 mol) were added sequentially to a three-necked flask connected to a condenser, and the mixture was stirred continuously until the reaction was complete (approximately 32 h).

[0077] The method to determine whether the reaction is complete is as follows: use a gas chromatography-mass spectrometry (GC-MS) instrument to monitor the mixture of the reaction system in real time. When 1-octadecane is completely consumed, the reaction is considered complete.

[0078] S2. Purification: Under dry conditions, the mixture obtained in step S1 is subjected to atmospheric distillation (temperature approximately 40°C) to remove excess dimethylchlorosilane, and 259.23 g of dimethylchlorosilane is recovered (recovery rate 68.5%, the ratio of recovered mass to feed mass, this parameter is calculated in the same way in the following embodiments). Then, the remaining liquid is dried by rotary evaporation at 50°C and then quickly filtered to obtain the target compound in liquid form. The solid part is solid particles of chloroplatinic acid.

[0079] In this step, the standard for rotary evaporation is a sudden temperature rise in the suspended system. The instrument used in this step is the same as that used in step S1. During the rotary evaporation process, the mouths of the flasks on both sides are sealed.

[0080] Example 2

[0081] This embodiment prepares an octadecyldimethylchlorosilane. The specific process differs from that in Example 1 in that:

[0082] In step S1, the dosage of chloroplatinic acid hexahydrate is 8.63 mg, 1.67 * 10 -5 mol.

[0083] Correspondingly, in step S1 of this embodiment, the reaction takes approximately 18 hours to complete.

[0084] In this embodiment, the yield of dimethylchlorosilane is comparable to that in the previous embodiment.

[0085] Example 3

[0086] This embodiment prepares an octadecylmethylethylchlorosilane, and the specific process differs from that in Example 1 in that:

[0087] In step S1, dimethylchlorosilane is replaced with an equal amount of methylethylchlorosilane;

[0088] Correspondingly, in step S1 of this embodiment, the time required for the reaction to be complete is approximately 30 hours.

[0089] Correspondingly, in step S2 of this embodiment, the mass of methyl ethyl chlorosilane recovered is 309.84 g, corresponding to a yield of 71.3%.

[0090] Example 4

[0091] This embodiment prepared an octadecyldimethylchlorosilane, which differs from Example 1 in that:

[0092] This embodiment uses the chloroplatinic acid catalyst recovered in Example 1;

[0093] The results obtained differ from those of Example 1 in the following ways:

[0094] When chloroplatinic acid is used for the second time (when the recovered chloroplatinic acid is used for the first time), the total reaction time is extended to 43 hours;

[0095] When chloroplatinic acid was used for the third time, the total reaction time was extended to 59 hours;

[0096] When chloroplatinic acid was used for the fourth time, the total reaction time was extended to 96 hours.

[0097] However, the yield of octadecyl dimethylchlorosilane obtained with each repeated use was the same as in Example 1.

[0098] In this embodiment, the method for determining the reaction time is the same as in Example 1.

[0099] Comparative Example 1

[0100] This embodiment prepares an octadecylmethylethylchlorosilane, and the specific process differs from that in Example 1 in that:

[0101] In step S1, the amount of dimethylchlorosilane used is 3 mol.

[0102] Comparative Example 2

[0103] This embodiment prepares an octadecylmethylethylchlorosilane, and the specific process differs from that in Example 1 in that:

[0104] In step S1, the reaction temperature is 50°C, and the reaction vessel is a sealed, pressure-resistant container.

[0105] Test case

[0106] In this test example, the purity of the products obtained in Examples 1-4 and Comparative Examples 1-2 was quantitatively tested using gas chromatography-mass spectrometry (GC-MS). The test results showed that the purity of the product obtained in Example 1 was 99%, the purity of the product obtained in Example 2 was 98.5%, the purity of the product obtained in Example 3 was 98.8%, and in Example 4, the purity of the product was 98.2%, 97.9%, and 97.3% respectively when chloroplatinic acid was used for the 2nd to 4th times. In Comparative Examples 1-2, the purity of the product was 89.1% and 93.6% respectively. This demonstrates that the preparation method provided by the present invention can obtain hydrocarbon-based chlorosilanes with high purity.

[0107] The second aspect of this test example calculated the yields of the products obtained in Examples 1-4 and Comparative Examples 1-2. Specifically, the yield was calculated as (mass of the target product × purity of the product) / theoretical mass of the target product. The theoretical mass of the target product represents the mass of the target product that could be obtained by reacting according to the proportions in the chemical reaction formula. The results showed that the yields of the products in Examples 1-4 were almost 100%, i.e., the yield was calculated as follows: (yield after purification; the sum of the mass of the three-necked flask and its contents after purification, minus the mass of the three-necked flask, equals the mass of the target product; the ratio of the target product mass to the theoretically obtainable mass is the yield). This demonstrates that the preparation method provided by this invention significantly suppresses the occurrence of side reactions. In Comparative Example 1, because the compound obtained from Formula I did not react completely, the product yield was only about 95%. In Comparative Example 2, because the increased temperature promoted the formation of complex side reactions to some extent, the product yield was only about 93%.

[0108] The third aspect of this test example involves testing the NMR results of the products obtained in Examples 1-3. The results show no impurity peaks in the NMR results, which further corroborates the high purity of the products obtained by this invention. Specifically:

[0109] The NMR results of the product obtained in Example 1 are as follows:

[0110] 13 C NMR (CDCl3) δ: 33.05, 32.00, 29.78, 29.76, 29.74, 29.60, 29.44, 29.32, 23.07, 22.74, 22.07, 22.74, 19.03, 14.13, 1.72.

[0111] 1 H NMR(CDCl3)δ: 0.39(s,6H),0.79-0,81(t,2H),0.86-0.88(m,3H),1.24-1.41(m,32H).

[0112] The NMR results of the products obtained in Examples 2 and 4 are almost the same as those in Example 1.

[0113] The NMR results of the product obtained in Example 3 are as follows:

[0114] 1 H NMR (CDCl3) δ: 0.41 (s, 3H), 0.60-0.81 (t, 7H), 0.86-0.94 (m, 5H), 1.24-1.41 (m, 32H).

[0115] 13 C NMR (CDCl3) δ: 33.15, 32.07, 29.78, 29.76, 29.73, 29.64, 29.44, 29.35, 23.12, 22.55, 22.10, 22.77, 19.04, 13.40, 14.12, 2.05, 1.85.

[0116] In summary, the preparation method provided by this invention can indeed improve the yield and purity of the target product while simplifying the preparation process and enhancing preparation safety.

[0117] The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention. Furthermore, the embodiments of the present invention and the features thereof can be combined with each other unless otherwise specified.

Claims

1. A method for preparing a hydrocarbon-based chlorosilane, characterized in that, The preparation method includes performing a hydrosilylation reaction of the compound shown in Formula I and the compound shown in Formula II under the catalysis of a platinum catalyst to obtain the hydrocarbon chlorosilane shown in Formula III; in: In Formula I, R1 is a C4 to C18 alkyl group; In Formula II, R2 and R3 are independently selected from C1 to C3 alkyl groups; The molar ratio of the compound shown in Formula I to the compound shown in Formula II is 1:3.5 to 4; The molar ratio of the compound shown in Formula I to the platinum catalyst is 55,000 to 3,000,000:1; The conditions for the hydrosilylation are room temperature and normal pressure; the room temperature is 10–40°C. The platinum catalyst is at least one of anhydrous chloroplatinic acid and chloroplatinic acid containing crystal water; The yield of the hydrocarbon-based chlorosilane shown in Formula III is ≥99%, and the purity is ≥97%.

2. The preparation method according to claim 1, characterized in that, In Formula I, R1 is a C15 to C16 alkyl group.

3. The preparation method according to claim 1, characterized in that, In Formula II, R2 and R3 are independently selected from C1 or C2 alkyl groups.

4. The preparation method according to any one of claims 1 to 3, characterized in that, The molar ratio of the compounds shown in Formula I to those shown in Formula II is 1:

4.

5. The preparation method according to any one of claims 1 to 3, characterized in that, The preparation method further includes purifying the hydrocarbon chlorosilane of Formula III after the hydrosilylation reaction.

6. The preparation method according to claim 5, characterized in that, The purification process includes sequential atmospheric distillation and rotary evaporation.

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