A combined catalyst and use thereof

Abstract

The application provides a combination catalyst and application thereof, and belongs to the technical field of fine chemical industry.The combination catalyst is composed of a phase transfer catalyst, an antioxidant and a buffer agent; the phase transfer catalyst is a crown ether phase transfer catalyst; the antioxidant is one or more of dilauryl thiodipropionate, dioctadecyl thiodipropionate, triphenyl phosphite and pentaerythritol diphosphite; and the buffer agent is one or more of potassium carbonate, sodium hydroxide and sodium bicarbonate.The combination catalyst has high activity, and when used in the reaction of synthesizing sodium thiocyanate and chloropropyl triethoxysilane, the combination catalyst has mild conditions, small dosage, easy control, simple operation, short reaction time, high yield, few by-products, reduced production cost, and improved product yield and quality.

Description

Technical Field

[0001] This invention relates to the field of fine chemical technology, and in particular to a combined catalyst and its application. Background Technology

[0002] Thiocyanopropyltriethoxysilane (trade name: Si-264) is a high-performance coupling agent. This coupling agent performs well in NBR, IR, BR, SBR, EPDM, and other rubbers. It not only increases the resistance of natural rubber vulcanizates to vulcanization reduction but also improves their tear resistance, abrasion resistance, and flexural crack resistance. Its properties are more stable than bis-(triethoxysilylpropyl)tetrasulfide, and it is less likely to cause rubber scorching. Thiocyanosilane itself has a light color, therefore it can be used in some light-colored rubber products, such as white rubber shoe soles.

[0003] In the catalytic synthesis of thiocyanopropyltriethoxysilane, typical catalysts include quaternary ammonium salts such as tetramethylammonium chloride, and quaternary phosphonium salts such as triphenylethylphosphorus bromide and tetraphenylphosphorus bromide. These catalysts effectively promote the reaction process and play an indispensable role in the synthesis of this compound. Studies have shown that tetrabutylammonium bromide exhibits superior catalytic activity compared to ammonium chloride catalysts, increasing the purity of thiocyanopropyltriethoxysilane to approximately 95%. However, the introduction of this catalyst has significant drawbacks: on the one hand, its residual components can adversely affect the application performance of subsequent products; on the other hand, it easily leads to yellowing of the product and significantly reduces its storage stability. Chinese patent document CN105061485A discloses a method for synthesizing thiocyanopropyltrialkoxysilane. In the process of synthesizing thiocyanopropyltrialkoxysilane, the catalyst treatment takes as long as 6.5-10.5 hours. The lengthy treatment cycle not only significantly prolongs the production cycle and reduces the output efficiency per unit time, but also greatly increases energy consumption and equipment occupation costs, which seriously restricts the advancement of industrial continuous production and makes it difficult to meet the actual needs of industrial production for high efficiency and economy.

[0004] Therefore, selecting suitable catalysts and additives to improve the conversion rate of raw materials and effectively suppress the yellowing phenomenon of the target product is the core point of this process. Summary of the Invention

[0005] In view of this, the present invention aims to provide a combined catalyst and its application. The synthesis of thiocyanopropyltriethoxysilane using the combined catalyst provided by the present invention can effectively suppress the yellowing phenomenon of the product.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] One of the technical solutions of this invention is a combined catalyst, which is composed of a phase transfer catalyst, an antioxidant, and a buffer.

[0008] The phase transfer catalyst is a crown ether-based phase transfer catalyst;

[0009] The antioxidant is one or more of dilaurate thiodipropionate, dioctadecyl thiodipropionate, triphenyl phosphite, and pentaerythritol diphosphite.

[0010] The buffer is one or more of potassium carbonate, sodium hydroxide, and sodium bicarbonate.

[0011] In a preferred embodiment of the present invention, the crown ether phase transfer catalyst is one or more of 18-crown ether-6, 15-crown ether-5, dibenzo-18-crown ether-6, di(tert-butylcyclohexane)-18-crown-6 and di(tert-butylbenzo)-18-crown-6.

[0012] In a preferred embodiment of the present invention, the mass ratio of the phase transfer catalyst, antioxidant and buffer is 70-75:20-25:1-5.

[0013] In a preferred embodiment of the present invention, the water content of the combined catalyst is <0.05%.

[0014] The second technical solution of the present invention is the application of the above-mentioned combined catalyst in the preparation of thiocyanopropyltriethoxysilane.

[0015] The third technical solution of the present invention is a method for preparing thiocyanopropyltriethoxysilane, which uses chloropropyltriethoxysilane and sodium thiocyanate as raw materials and reacts them under the action of the above-mentioned combined catalyst to obtain thiocyanopropyltriethoxysilane (Si-264).

[0016] In a preferred embodiment of the present invention, the molar ratio of sodium thiocyanate to chloropropyltriethoxysilane is 1.0 to 1.2:1; and the amount of the combined catalyst is 0.05% to 0.15% of the total mass of chloropropyltriethoxysilane and sodium thiocyanate.

[0017] Specifically, the combined catalyst is used in an amount of 0.05%, 0.1%, or 0.15% of the total mass of chloropropyltriethoxysilane and sodium thiocyanate.

[0018] In a preferred embodiment of the present invention, the reaction temperature is 100-105°C and the reaction time is 0.5-1.5 h.

[0019] Specifically, the reaction temperature is 100℃, 103℃ or 105℃, and the time is 0.5h, 1h or 1.5h.

[0020] In a preferred embodiment of the present invention, after the reaction is completed, a post-processing step is further included.

[0021] In a preferred embodiment of the present invention, the post-processing is as follows: first, centrifugation is used to remove the salt from the obtained reaction solution, followed by distillation to collect the fraction at 140–145°C. Specifically: the obtained reaction solution is analyzed by gas chromatography. When the Si-264 content in the crude reaction product reaches 97% or more, the salt is removed by centrifugation; then, vacuum distillation is performed to first remove the fraction below 140°C (10 mmHg), and then vacuum distillation is performed to collect the fraction at 140–145°C (10 mmHg).

[0022] The present invention discloses the following technical effects:

[0023] 1. The combined catalyst of the present invention has high activity and is used in the synthesis of sodium thiocyanate and chloropropyltriethoxysilane. The reaction conditions are mild, the amount of combined catalyst is small and easy to control, the operation is simple, the synthesis reaction time is short, the yield is high, and the by-products are few, which reduces the production cost and improves the yield and quality of the product.

[0024] 2. The combined catalyst used in this invention effectively improves reaction efficiency and increases the yield of reaction products. The product quality is good, the stability is good, and no yellowing phenomenon occurs in the later stage, meeting the high standard requirements of mid- and downstream product applications.

[0025] 3. The combined catalyst of this invention requires a small amount (0.1%) and has a high yield (yield reaches 99%, and product content can reach over 99%). The synthesis of sodium thiocyanate and chloropropyltriethoxysilane involves almost no wastewater, waste residue, or waste liquid, making it an economical and environmentally friendly green chemical synthesis. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 The images show the appearance of Si-264 prepared in Example 1 and Comparative Example 2 after 3 months of storage. The left image is of Example 1 and the right image is of Comparative Example 1.

[0028] Figure 2 The image shows the gas chromatogram of Si-264 prepared in Example 1.

[0029] Figure 3 The image shows the gas chromatogram of Si-264 prepared in Comparative Example 1. Detailed Implementation

[0030] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0031] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0032] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0033] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0034] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0035] Unless otherwise specified, the technical solutions described in this invention are all conventional solutions in the field, and the reagents or raw materials used are all purchased from commercial channels or are publicly available unless otherwise specified.

[0036] In the embodiments, the preparation method of the combined catalyst is as follows: the phase transfer catalyst, antioxidant and buffer are mixed evenly.

[0037] To better understand the present invention, the following embodiments further illustrate the content of the present invention, but the content of the present invention is not limited to the following embodiments.

[0038] Example 1

[0039] A composite catalyst comprising a phase transfer catalyst, an antioxidant, and a buffer;

[0040] The phase transfer catalyst is 18-crown ether-6, the antioxidant is dilauryl thiodipropionate, and the buffer is potassium carbonate. The mass ratio of the phase transfer catalyst, antioxidant, and buffer is 70:25:5.

[0041] A method for preparing Si-264, comprising the following steps:

[0042] In a 1000ml high-pressure reactor equipped with an electric stirrer and thermometer, 240.8g (1mol) of chloropropyltriethoxysilane was added. After stirring was started, 81g (1mol) of sodium thiocyanate and 0.33g of the above-mentioned combined catalyst were added. The temperature was raised to 100-105℃ and the reaction was maintained for 1 hour. After the reaction was completed, a sample was taken and analyzed by gas chromatography. The crude product content was 97%. After salt separation, the fraction collected at 140-145℃ / 10mmHg was obtained by vacuum distillation, yielding Si-264 (thiocyanopropyltriethoxysilane) with a yield of 99.1% and a refined product content greater than 99%.

[0043] Figure 2 This is the gas chromatogram of Si-264 prepared in this embodiment.

[0044] Example 2

[0045] A composite catalyst comprising a phase transfer catalyst, an antioxidant, and a buffer;

[0046] The phase transfer catalyst is 15-crown ether-5, the antioxidant is dioctadecyl thiodipropionate, and the buffer is sodium hydroxide. The mass ratio of the phase transfer catalyst, antioxidant, and buffer is 75:20:5.

[0047] A method for preparing Si-264, comprising the following steps:

[0048] In a 1000 ml high-pressure reactor equipped with an electric stirrer and thermometer, 361.2 g (1.5 mol) of chloropropyltriethoxysilane was added. After stirring, 145.8 g (1.8 mol) of sodium thiocyanate and 0.507 g of the above-mentioned combined catalyst were added. The temperature was raised to 100-105 °C and the reaction was maintained for 1 h. Gas chromatography analysis of the sample showed that the crude product content was 98%. After salt separation, the fraction collected at 140-145 °C / 10 mmHg was obtained by vacuum distillation, yielding Si-264 (thiocyanopropyltriethoxysilane) with a yield of 99.3% and a refined product content greater than 99%.

[0049] Example 3

[0050] A composite catalyst comprising a phase transfer catalyst, an antioxidant, and a buffer;

[0051] The phase transfer catalyst is dibenzo-18-crown ether-6, the antioxidant is triphenyl phosphite, and the buffer is sodium bicarbonate. The mass ratio of the phase transfer catalyst, antioxidant, and buffer is 73:23:4.

[0052] A method for preparing Si-264, comprising the following steps:

[0053] In a 500ml high-pressure reactor equipped with an electric stirrer and thermometer, 120.4g (0.5mol) of chloropropyltriethoxysilane was added. After stirring, 44.6g (0.55mol) of sodium thiocyanate and 0.165g of the above-mentioned combined catalyst were added. The temperature was raised to 100-105℃ and the reaction was maintained for 1 hour. Gas chromatography analysis of the sample showed that the crude product content was 98%. After salt separation, the fraction collected at 140-145℃ / 10mmHg was obtained by vacuum distillation, yielding Si-264 (thiocyanopropyltriethoxysilane) with a yield of 99.1% and a refined product content greater than 99%.

[0054] Example 4

[0055] A composite catalyst comprising a phase transfer catalyst, an antioxidant, and a buffer;

[0056] The phase transfer catalyst is bis(tert-butylcyclohexane)-18-crown-6, the antioxidant is dilauryl thiodipropionate, and the buffer is sodium hydroxide. The mass ratio of the phase transfer catalyst, antioxidant, and buffer is 74:24:2.

[0057] A method for preparing Si-264, comprising the following steps:

[0058] In a 2000 ml high-pressure reactor equipped with an electric stirrer and thermometer, 722.4 g (3 mol) of chloropropyltriethoxysilane was added. After stirring, 291.6 g (3.6 mol) of sodium thiocyanate and 1.014 g of the above-mentioned combined catalyst were added. The temperature was raised to 100-105 °C and the reaction was maintained for 1 h. Gas chromatography analysis of the sample showed that the crude product content was 98%. After salt separation, the fraction collected at 140-145 °C / 10 mmHg was obtained by vacuum distillation, yielding Si-264 (thiocyanopropyltriethoxysilane) with a yield of 99.2% and a refined product content greater than 99%.

[0059] Example 5

[0060] A composite catalyst comprising a phase transfer catalyst, an antioxidant, and a buffer;

[0061] The phase transfer catalyst is bis(tert-butylphenyl)-18-crown-6, the antioxidant is pentaerythritol diphosphite, and the buffer is sodium hydroxide. The mass ratio of the phase transfer catalyst, antioxidant, and buffer is 72:24:4.

[0062] A method for preparing Si-264, comprising the following steps:

[0063] In a 2000ml high-pressure reactor equipped with an electric stirrer and thermometer, 481.6g (2mol) of chloropropyltriethoxysilane was added. After stirring was started, 162g (2mol) of sodium thiocyanate and 0.66g of the above-mentioned combined catalyst were added. The temperature was raised to 100-105℃ and the reaction was maintained for 1 hour. Gas chromatography analysis of the sample showed that the crude product content was 98%. After salt separation, the fraction collected at 140-145℃ / 10mmHg was obtained by vacuum distillation, yielding Si-264 (thiocyanopropyltriethoxysilane) with a yield of 99.4% and a refined product content greater than 99%.

[0064] Comparative Example 1

[0065] A method for preparing Si-264, comprising the following steps:

[0066] In a 1000ml high-pressure reactor equipped with an electric stirrer and thermometer, 240.8g (1mol) of chloropropyltriethoxysilane was added. After stirring, 81g (1mol) of sodium thiocyanate and 0.5g of catalyst SC550 (tetrabutylammonium bromide) were added. The temperature was raised to 100-105℃ and maintained for 1 hour. After the reaction was completed, a sample was taken and analyzed by gas chromatography. The crude product content was 96%. After salt separation, the fraction collected at 140-145℃ / 10mmHg was obtained by vacuum distillation, yielding Si-264 (thiocyanopropyltriethoxysilane) with a yield of 97% and a refined product content greater than 98%.

[0067] Figure 3 The gas chromatogram of Si-264 prepared in this comparative example is shown.

[0068] Figure 1 The images show the appearance of Si-264 prepared in Example 1 and Comparative Example 2 after 3 months of storage. The left image is from Example 1, and the right image is from Comparative Example 1. It can be seen that the Si-264 prepared using the catalyst of this application did not show any yellowing after 3 months of storage.

[0069] Depend on Figure 2 and Figure 3 The comparison shows that the catalyst of this application can successfully catalyze the reaction of sodium thiocyanate with chloropropyltriethoxysilane to obtain Si-264.

[0070] Comparative Example 2

[0071] A catalyst, namely 18-crown ether-6.

[0072] A method for preparing Si-264, comprising the following steps:

[0073] In a 1000 ml high-pressure reactor equipped with an electric stirrer and thermometer, 240.8 g (1 mol) of chloropropyltriethoxysilane was added. After stirring, 121.5 g (1.5 mol) of sodium thiocyanate and 0.33 g of 18-crown ether-6 were added. The temperature was raised to 100-105 °C and maintained for 1 h. After the reaction was completed, a sample was taken and analyzed by gas chromatography. The crude product content was 75%. After salt separation, the fraction collected at 140-145 °C / 10 mmHg was obtained by vacuum distillation, yielding Si-264 (thiocyanopropyltriethoxysilane) with a yield of 70%.

[0074] Comparative Example 3

[0075] A catalyst, differing from the combined catalyst of Example 1 only in that the buffer is omitted.

[0076] A method for preparing Si-264, comprising the following steps:

[0077] In a 1000 ml high-pressure reactor equipped with an electric stirrer and thermometer, 240.8 g (1 mol) of chloropropyltriethoxysilane was added. After stirring was started, 81 g (1 mol) of sodium thiocyanate and 0.33 g of the above catalyst were added. The temperature was raised to 100-105 °C and the reaction was maintained for 1 h. After the reaction was completed, a sample was taken and analyzed by gas chromatography. The crude product content was 82%. After salt separation, the fraction collected at 140-145 °C / 10 mmHg was obtained by vacuum distillation, yielding Si-264 (thiocyanopropyltriethoxysilane) with a yield of 76%.

[0078] Comparative Example 4

[0079] A catalyst, which differs from the combined catalyst of Example 1 only in that the antioxidant is omitted.

[0080] A method for preparing Si-264, comprising the following steps:

[0081] In a 1000 ml high-pressure reactor equipped with an electric stirrer and thermometer, 240.8 g (1 mol) of chloropropyltriethoxysilane was added. After stirring was started, 81 g (1 mol) of sodium thiocyanate and 0.33 g of the above catalyst were added. The temperature was raised to 100-105 °C and the reaction was maintained for 1 h. After the reaction was completed, a sample was taken and analyzed by gas chromatography. The crude product content was 78%. After salt separation, the fraction collected at 140-145 °C / 10 mmHg was obtained by vacuum distillation, yielding Si-264 (thiocyanopropyltriethoxysilane) with a yield of 73%.

[0082] Comparative Example 5

[0083] A catalyst, differing from the combined catalyst of Example 1, is provided in that the mass ratio of phase transfer catalyst, antioxidant, and buffer is 65:26:9.

[0084] A method for preparing Si-264, comprising the following steps:

[0085] In a 1000 ml high-pressure reactor equipped with an electric stirrer and thermometer, 240.8 g (1 mol) of chloropropyltriethoxysilane was added. After stirring, 81 g (1 mol) of sodium thiocyanate and 0.33 g of the above catalyst were added. The temperature was raised to 100-105 °C and maintained for 1 h. After the reaction was completed, a sample was taken and analyzed by gas chromatography. The crude product content was 90%. After salt separation, the fraction collected at 140-145 °C / 10 mmHg was obtained by vacuum distillation, yielding Si-264 (thiocyanopropyltriethoxysilane) with a yield of 92%.

[0086] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing thiocyanopropyltriethoxysilane, characterized in that, Using chloropropyltriethoxysilane and sodium thiocyanate as raw materials, a reaction was carried out under the action of a combined catalyst to obtain thiocyanopropyltriethoxysilane; The reaction temperature is 100-105℃; After the reaction is completed, a post-processing step is also included. The post-processing is as follows: the obtained reaction solution is analyzed by gas chromatography. When the Si-264 content in the crude product reaches more than 97%, the salt is removed by centrifugation. Then, vacuum distillation is performed to first remove the fraction below 140℃ (10 mmHg), and then the fraction at 140-145℃ (10 mmHg) is collected by vacuum distillation. Almost no wastewater, waste residue, or waste liquid is generated in the whole process. The combined catalyst consists of a phase transfer catalyst, an antioxidant, and a buffer. The phase transfer catalyst is a crown ether-based phase transfer catalyst; The antioxidant is one or more of dilaurate thiodipropionate, dioctadecyl thiodipropionate, triphenyl phosphite, and pentaerythritol diphosphite. The buffer is one or more of potassium carbonate, sodium hydroxide, and sodium bicarbonate; The mass ratio of the phase transfer catalyst, antioxidant and buffer is 70-75:20-25:1-5; The combined catalyst has a water content of <0.05%; The combined catalyst is used in an amount of 0.05%-0.15% of the total mass of chloropropyltriethoxysilane and sodium thiocyanate.

2. The method for preparing thiocyanopropyltriethoxysilane according to claim 1, characterized in that, The crown ether phase transfer catalyst is one or more of 18-crown ether-6, 15-crown ether-5, dibenzo-18-crown ether-6, di(tert-butylcyclohexane)-18-crown-6 and di(tert-butylbenzo)-18-crown-6.

3. The method for preparing thiocyanopropyltriethoxysilane according to claim 1, characterized in that, The molar ratio of sodium thiocyanate to chloropropyltriethoxysilane is 1.0 to 1.2:

1.

4. The method for preparing thiocyanopropyltriethoxysilane according to claim 1, characterized in that, The reaction time is 0.5-1.5 hours.

Images