Preparation method of high-stability inhibitor modified white carbon black and application of high-stability inhibitor modified white carbon black in platinum catalytic system

Abstract

The invention belongs to the technical field of silicon rubber hydrosilylation reaction catalysis, and particularly relates to a preparation method of high-stability inhibitor modified white carbon black and application of the high-stability inhibitor modified white carbon black in a platinum catalytic system. The preparation method comprises the following specific steps: firstly, carrying out addition on o-propenyloxybenzaldehyde 1 and an ethynyl Grignard reagent to prepare an alkynol intermediate 2; then carrying out secondary addition on the alkynol intermediate 2 and trialkoxy hydrogen siloxane to prepare an intermediate 3; and finally modifying white carbon black with the intermediate 3 to prepare SG-0. The complex can be used as an inhibitor with high stability and high dispersion degree and can be compounded with a platinum catalyst for use, and an obtained platinum catalytic system is good in stability and high in catalytic activity. When the silicon rubber is applied to the field of silicon rubber, the silicon rubber can have excellent storage stability without adding an extra inhibitor.

Description

Technical Field

[0001] The invention relates to the technical field of catalytic technology of silicone rubber hydrosilylation reaction, and specifically to a method for preparing high-stability inhibitor-modified white carbon black and application thereof in a platinum catalytic system. Background Art

[0002] Silicone rubber has excellent properties such as high and low temperature resistance, oxygen resistance, weather resistance, and heat insulation. Therefore, silicone rubber is widely used in automobiles, food, medical treatment, etc. There are two main types of catalysts used in the silicone rubber molding process, namely peroxide catalysts and platinum catalysts. The platinum catalyst system can effectively catalyze the silane addition reaction between silicon-hydrogen bonds and unsaturated bonds. It has many advantages such as high catalytic activity, high processing efficiency, no by-product generation, and environmental friendliness, and is generally favored by the industry.

[0003] However, due to the high activity of platinum catalyst, it can catalyze the latent curing of silicone rubber at room temperature. In order to increase its operable time, platinum catalyst must be used in conjunction with inhibitors during use. Alkynol compounds, maleate compounds, phosphite compounds, and carbazole compounds are all commonly used reaction inhibitors. Among them, acetylene cyclohexanol is a commonly used acetylene alcohol inhibitor, which has many advantages such as low price, excellent inhibition performance and good compatibility with silicone rubber system, so it is widely used in the industry.

[0004] However, ethynyl cyclohexanol still has the following disadvantages:

[0005] First: It is volatile at room temperature, which will seriously affect the long-term storage stability of silicone rubber;

[0006] Second: Direct mixing of ethynyl cyclohexanol and Castel catalyst can easily lead to the precipitation of platinum black, thus reducing the catalytic efficiency of the catalyst.

[0007] Therefore, the present invention provides a method for preparing highly stable inhibitor-modified silica and application thereof in a platinum catalytic system. Summary of the invention

[0008] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0009] A method for preparing high-stability inhibitor-modified white carbon black comprises the following specific steps:

[0010] Step 1, synthesis of intermediate 2: dissolve substrate 1 in THF solvent, slowly add acetylene Grignard reagent at zero degrees, stir at zero degrees for 30 minutes, then warm to room temperature for reaction, after monitoring the completion of the reaction of the raw materials, quench with water, extract, and purify by column to obtain intermediate 2, whose specific structural formula is shown as follows:

[0011]

[0012] Step 2, synthesis of intermediate 3: intermediate 2 and alkoxyhydrosilane are added to an organic solvent, and then a Custer catalyst is added, and the temperature is raised to react for two hours. After monitoring the completion of the reaction of the raw materials, the intermediate 3 is obtained after cooling, filtering, and washing with alcohol;

[0013] Step 3, synthesis of SG-0: Take fumed silica, add it to dry toluene, drop intermediate 3 into it, then heat it for four hours, cool it to room temperature, filter, wash, concentrate and dry it, and then you can get the product SG-0.

[0014] As a preferred embodiment of the method for preparing high-stability inhibitor-modified white carbon black described in the present invention, the alkoxyhydrogensilane is a mixture of one or more of trimethoxyhydrogensilane and triethoxyhydrogensilane.

[0015] As a preferred embodiment of the method for preparing high-stability inhibitor-modified white carbon black described in the present invention, the organic solvent is a mixture of one or more of toluene, dichloromethane, petroleum ether, tetrahydrofuran, and N,N-dimethylformamide.

[0016] As a preferred embodiment of the method for preparing a high-stability inhibitor-modified silica according to the present invention, the heating temperature in step 2 is 50-110°C, and the heating temperature in step 3 is 50-110°C.

[0017] As a preferred embodiment of the method for preparing high-stability inhibitor-modified silica described in the present invention, the alcohol is a mixture of one or more of methanol, ethanol and isopropanol.

[0018] According to the above-mentioned method for preparing high-stability inhibitor-modified silica and its application as an inhibitor in a platinum catalytic system.

[0019] The preparation method provided by the present invention is to prepare an acetylene alcohol intermediate by addition reaction of o-propyleneoxybenzaldehyde and acetylene Grignard reagent, then prepare a novel silane coupling agent by secondary addition reaction with trialkoxyhydrogensiloxane, and finally prepare SG-0 by modifying white carbon black.

[0020] Compared with existing technologies:

[0021] 1. The preparation method provided by the present invention is easy to operate and has a high reaction yield. Therefore, the industrial production efficiency is high and it is easy to realize industrial production;

[0022] 2. The SG-0 prepared by the preparation method provided by the present invention has good stability at room temperature and high temperature. In addition, since a monolayer of silane is formed on the surface of white carbon black, the dispersion is better, and the problem of platinum being oxidized after mixing with platinum can be avoided. Therefore, the catalytic efficiency is high when applied to platinum hydrosilylation catalysis. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of the preparation of the platinum flame retardant for silicone rubber. DETAILED DESCRIPTION

[0024] In order to make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be described in further detail below.

[0025] Embodiment 1:

[0026] The present invention provides a method for preparing high-stability inhibitor-modified white carbon black, comprising the following specific steps:

[0027] Step 1: 16.2 g of substrate 1 was dissolved in 160 mL of THF, 400 mL (0.5 M) of ethynylmagnesium bromide was slowly added at zero degrees, and the mixture was stirred at zero degrees for 30 min, and then the mixture was warmed to room temperature for reaction. After monitoring the completion of the reaction of the raw material, 20 mL of saturated ammonium chloride was added to quench the reaction, and the aqueous phase was extracted three times with ethyl acetate. The organic phase was then dried over anhydrous sodium sulfate, concentrated under reduced pressure, and purified by column to obtain 17 g of intermediate 2;

[0028] Step 2: Add 5.6 g of intermediate 2 and 4.9 g of triethoxysilane to 50 mL of toluene, then add 2 drops of 0.1 M Custer catalyst, react at 90 ° C for two hours, and after monitoring the completion of the reaction of the raw materials, cool, filter, and wash with methanol to obtain the target product 10 g 3-A;

[0029] Step 3: Take 30g of fumed silica, add it to 250mL of dry toluene, drop 2g of intermediate 3-A, then react at 110°C for four hours, cool to room temperature, filter, wash, concentrate and dry, and you can get 32g of product SG-0A.

[0030] Embodiment 2:

[0031] The present invention provides a method for preparing high-stability inhibitor-modified white carbon black, comprising the following specific steps:

[0032] Step 1: Same as step (1) in Example 1;

[0033] Step 2: Add 5.6 g of intermediate 2 and 3.6 g of trimethoxysilane to 50 mL of toluene, then add 2 drops of 0.1 M Custer catalyst, react at 90 ° C for two hours, and after monitoring the completion of the reaction of the raw materials, cool, filter, and wash with methanol to obtain the target product 9g 3-B;

[0034] Step 3: Take 30g of fumed silica, add it to 250mL of dry toluene, drop 2g of intermediate 3-B, then react at 110°C for four hours, cool to room temperature, filter, wash, concentrate and dry, and you can get 32g of product SG-0B.

[0035] Comparative Example 1:

[0036] Intermediate 2 was used as inhibitor.

[0037] Comparative Example 2:

[0038] As inhibitor, ethynylcyclohexanol was used.

[0039] a. Test of high temperature vulcanization performance

[0040] Take 100g of liquid silicone rubber (Dongguan Beiteli New Materials Co., Ltd.), then add 4.8% SG-0A, 4.8% SG-0B, 0.3% intermediate 2 and 0.3% ethynyl cyclohexanol inhibitor respectively, stir evenly for 5-10 minutes, then add Custer catalyst (10ppm), stir for five minutes, and vulcanize at a temperature of 160°C for 5 minutes to obtain silicone rubber samples A, B, C, and D.

[0041] Table 1 below shows the vulcanization results of silicone rubber samples A, B, C, and D prepared in the examples and comparative examples.

[0042] Table 1 High temperature catalytic results of examples and comparative examples

[0043]

[0044] As can be seen from Table 1, the inhibitors SG-0A and SG-0B prepared in Examples 1 and 2 have similar vulcanization effects on the high-temperature catalytic silicone rubber composition as the inhibitor 2 and ethynyl cyclohexanol in Comparative Examples 1 and 2, and do not affect the catalytic activity and sulfur transformation performance of the platinum catalyst.

[0045] b. Room temperature stability test

[0046] Take 100g of liquid silicone rubber (Dongguan Beiteli New Materials Co., Ltd.), then add 4.8% SG-0A, 4.8% SG-0B, 0.3% intermediate 2 and 0.3% ethynyl cyclohexanol inhibitor and stir evenly for 5-10min, then add Custer catalyst (10ppm), stir for five minutes, and mark as samples A1, B1, C1, D1 respectively. All samples are sealed and placed in an environment of 25°C, and the viscosity of the composition is measured regularly with a rotational viscometer (Shanghai Changji Geological Instrument Co., Ltd., model: NDJ-8S).

[0047] The viscosity of the above samples was measured at room temperature, as shown in Table 2.

[0048] Table 2 below shows the viscosity changes of silicone rubber samples A1, B1, C1, and D1 prepared in the examples and comparative examples.

[0049]

[0050]

[0051] As shown in Table 2, under the same molar ratio, when 4.8% SG-0A, 4.8% SG-0B, 0.3% intermediate 2 and 0.3% ethynyl cyclohexanol are added to liquid silicone rubber, the viscosity of silicone rubber samples C1 and D1 increases rapidly and cannot be used in industrial production. By comparison, it is found that after the inhibitors SG-0A and SG-0B prepared by the method of the present invention are added to liquid silicone rubber, the liquid silicone rubber can have an operating time of more than 60 days and has high stability.

[0052] From Table 1 and Table 2, it can be seen that the inhibitors SG-0A and SG-0B prepared by the method of the present invention can be applied to the hydrosilylation platinum catalyst. At room temperature, the platinum catalyst can be well inhibited, and no additional inhibitors need to be added during use. The room temperature stability is good; in addition, the cross-linking reaction can be quickly achieved under high temperature conditions; therefore, this type of inhibitor can be conveniently applied to the silicone rubber field.

[0053] Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for preparing high-stability inhibitor-modified white carbon black, characterized in that: The specific steps are as follows: Step 1, synthesis of intermediate 2: dissolve substrate 1 in THF solvent, slowly add acetylene Grignard reagent at zero degrees, stir at zero degrees for 30 minutes, then warm to room temperature for reaction, after monitoring the completion of the reaction of the raw materials, quench with water, extract, and purify by column to obtain intermediate 2, whose specific structural formula is shown as follows: Step 2, synthesis of intermediate 3: intermediate 2 and alkoxyhydrosilane are added to an organic solvent, and then a Custer catalyst is added, and the temperature is raised to react for two hours. After monitoring the completion of the reaction of the raw materials, the intermediate 3 is obtained after cooling, filtering, and washing with alcohol; Step 3, synthesis of SG-0: Take fumed silica, add it to dry toluene, drop intermediate 3 into it, then heat it for four hours, cool it to room temperature, filter, wash, concentrate and dry it, and then you can get the product SG-0.

2. The method for preparing a high-stability inhibitor-modified silica according to claim 1, characterized in that: The alkoxyhydrogensilane is a mixture of one or more of trimethoxyhydrogensilane and triethoxyhydrogensilane.

3. The method for preparing a high-stability inhibitor-modified silica according to claim 1, characterized in that: The organic solvent is a mixture of one or more of toluene, dichloromethane, petroleum ether, tetrahydrofuran, and N,N-dimethylformamide.

4. The method for preparing a high-stability inhibitor-modified silica according to claim 1, characterized in that: The heating temperature in step 2 is 50-110°C, and the heating temperature in step 3 is 50-110°C.

5. The method for preparing a high-stability inhibitor-modified silica according to claim 1, characterized in that: The alcohol is a mixture of one or more of methanol, ethanol and isopropanol.

6. A method for preparing a highly stable inhibitor-modified silica according to any one of claims 1 to 5, and its use as an inhibitor in a platinum catalytic system.

Images