Novel process for synthesizing bis-((triethoxysilyl) propyl)-disulfide in water phase

Abstract

The invention relates to a novel process for synthesizing bis-((triethoxysilyl) propyl)-disulfide in a water phase, which comprises the following steps: (1) adding deionized water, anhydrous sodium sulfide hydrate and powdered sulfur into a reaction container, and stirring for reaction; (2) respectively weighing 3-chloropropyltriethoxysilane and a deep eutectic solvent, and stirring the 3-chloropropyltriethoxysilane and the deep eutectic solvent to prepare a mixed solution; (3) adding the mixed solution into a four-mouth reaction container through a constant-pressure dropping funnel, and monitoring the reaction process through gas chromatography; and (4) after the reaction is completed, cooling to room temperature, standing for layering, and treating an organic phase to obtain a product. The bis-((triethoxysilyl) propyl)-disulfide is prepared by adopting an aqueous phase synthesis method, water is taken as a solvent, and a deep eutectic solvent is adopted to replace a conventional phase transfer catalyst, so that migration and contact of reactants between two phases can be promoted, and the yield of the reaction products is increased; and the problems of residual risk and environmental pollution possibly caused by a traditional phase transfer catalyst are effectively avoided.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of chemical preparation, and particularly relates to a new process for water-phase synthesis of bis-〔(triethoxysilyl)propyl〕-disulfide. BACKGROUND

[0002] Bis-〔(triethoxysilyl)propyl〕-disulfide is an important organosilicon coupling agent, which is widely used in surface modification and interface reinforcement in the fields of rubber, plastic, paint, adhesive and composite material. Its molecular structure contains both hydrolysable triethoxysilane groups and disulfide bonds capable of forming covalent bonds with organic materials, and has good amphiphilic properties. The triethoxysilane groups can form stable siloxane bonds with the hydroxyl groups on the surface of inorganic materials such as silica, glass fiber and metal oxide after hydrolysis, while the disulfide bonds can crosslink with the organic polymer chains during the vulcanization process of rubber, thereby improving the bonding strength of rubber and inorganic fillers. Especially in the green tire manufacturing, it plays a role in coupling internal inorganic and organic components, improving the wet skid resistance of tires and reducing the rolling resistance.

[0003] In the traditional preparation process of bis-〔(triethoxysilyl)propyl〕-disulfide, an organic phase reaction system is usually used and phase transfer catalysts are relied on to promote the migration and contact of reactants between the two phases. However, the phase transfer catalysts are often difficult to completely remove after the reaction, and are easily left in the product. Not only will it cause the purity of the target product to decrease, but also will put higher requirements on the subsequent separation and purification process. The residual catalysts may also inhibit the actual application performance of the product, resulting in a decrease in the effective yield. Moreover, the phase transfer catalysts generally have certain environmental toxicity and non-degradability, and their use may also cause potential environmental pollution problems, which limits the application of the process in green synthesis and large-scale production. SUMMARY

[0004] In view of the problems existing in the prior art, the present application provides a new process for water-phase synthesis of bis-〔(triethoxysilyl)propyl〕-disulfide.

[0005] The technical scheme for solving the above technical problems is as follows: a new process for water-phase synthesis of bis-〔(triethoxysilyl)propyl〕-disulfide, comprising the following steps: (1) adding deionized water into a reaction container, and then adding anhydrous sodium sulfide hydrate and sulfur powder successively, and stirring to perform temperature control reaction; (2) weighing 3-chloropropyl triethoxysilane and deep eutectic solvent respectively, and stirring to obtain a mixed solution, the mass ratio of 3-chloropropyl triethoxysilane to deep eutectic solvent being 1:(1.1-1.5), and the deep eutectic solvent being L-menthol and thymol, the molar ratio of L-menthol to thymol being 1:(0.8-1.5); (3) the mixed solution prepared in step (2) is added into the reaction container in step (1), the dropping time is controlled, and the reaction is completed when the mass fraction of 3-chloropropyltriethoxysilane residue is less than 0.5% by monitoring by gas chromatography; (4) after the reaction is completed by monitoring in step (3), heating is stopped, cooling is performed to room temperature, and layering is performed after standing; the organic phase is taken, washed with saturated sodium chloride solution three times, dried with anhydrous sodium sulfate, filtered, and then equal volume of toluene is added, and vacuum concentration and short path distillation are performed, respectively, to obtain (bis-〔(triethoxysil) propyl〕-disulfide).

[0006] Further, the molar ratio of 3-chloropropyltriethoxysilane, anhydrous sodium sulfide hydrate and sulfur powder is 2: (1-1.2): (1-1.2).

[0007] Further, the reaction temperature of the temperature-controlled reaction in step (1) is 20-40°C, and the reaction time is 30-40 minutes.

[0008] Further, the dropping time of the mixed solution prepared in step (2) into the reaction container in step (1) in step (3) is 30-50 min, and the reaction is stirred at a speed of 150-200 rpm for 1.5-2 hours.

[0009] Further, the layering time after standing in step (4) is 20-40 minutes, the vacuum concentration condition is 50°C, 80 rpm, and the short path vacuum distillation condition is 100°C, 1 mbar.

[0010] The present application has the following beneficial effects: the bis-〔(triethoxysil) propyl〕-disulfide is prepared by the aqueous phase synthesis method, the method is simple to operate, water is used as the solvent, a deep eutectic solvent is used instead of a conventional phase transfer catalyst, the migration and contact of reactants between two phases can be promoted, and the residual risk and environmental pollution problems caused by the traditional phase transfer catalyst can be effectively avoided; secondly, the reaction condition is mild, a complex organic solvent system is not needed, the raw material utilization rate is high, the by-products are few, the product yield and purity are greatly improved, and the economic benefit is remarkable. BRIEF DESCRIPTION OF DRAWINGS

[0011] Figure 1 The process flow chart for preparing the bis-〔(triethoxysil) propyl〕-disulfide of the present application is shown in the figure. DETAILED DESCRIPTION

[0012] The principles and characteristics of the present application are described below in combination with the drawings, and the examples are only used to explain the present application, and are not used to limit the scope of the present application, if not specially stated, the reagents of the present application are conventional reagents in the art, and can be obtained by commercial purchase.

[0013] Example 1: 1. Preparation of deep eutectic solvent Deep eutectic solvent was composed of L-menthol and thymol with a molar ratio of 1:1. The specific preparation steps were as follows: 50.96 g of L-menthol and 49.04 g of thymol were weighed respectively, placed in a 200 mL beaker, stirred at 150 rpm on a 70°C constant temperature hot plate for 40 min until a uniform transparent liquid was formed, then transferred to a desiccator, vacuum dried at 60°C for 2 h, cooled and sealed for standby.

[0014] 2. Preparation of Bis-〔(triethoxysilyl)propyl〕-disulfide (1) In a 1000 mL four-necked round-bottom flask equipped with a magnetic stirrer, a thermometer, a constant pressure dropping funnel, and a spherical condenser, 300 mL of deionized water was added, and the reaction temperature was controlled at 20°C. 26.55 g of anhydrous sodium sulfide hydrate and 3.54 g of sulfur powder were weighed and added to the flask, and stirring was carried out at 150 rpm for 30 min. (2) Another 200 mL beaker was taken, 48.4 g of 3-chloropropyl triethoxysilane and 60 g of pre-dried deep eutectic solvent were weighed into the beaker, heated at 30°C and slowly stirred for 10 min until the 3-chloropropyl triethoxysilane was completely dissolved, obtaining a uniform transparent mixed solution; (3) The temperature of the reaction flask was heated to 35°C, and the mixed solution obtained in step (2) was added to the reaction flask at a constant speed through the constant pressure dropping funnel, and the dropping time was controlled for 30 min; after the addition was completed, the temperature of the system was slowly raised to 42°C, and the stirring was continued at 150 rpm for 1.5 h. During the reaction, a small amount of sample was taken every 30 min, diluted with n-hexane, and analyzed by gas chromatography. When the mass fraction of 3-chloropropyl triethoxysilane was less than 0.5% and there was no obvious peak of mercapto silane intermediate, the reaction was determined to be completed; (4) After the reaction was completed, the heating was stopped, and the system was naturally cooled to room temperature. After standing for 20 min, the water phase and the organic phase were separated, the organic phase was washed with saturated sodium chloride solution for 3 times, each time with 50 mL, then dried with anhydrous sodium sulfate for 30 min, filtered to remove the drying agent, and then 50 mL of toluene was added to the filtrate. The reagent was concentrated under reduced pressure at 50°C and 80 rpm, and then distilled under short-path reduced pressure at 100°C and 1 mbar to obtain a light yellow transparent liquid, which was Bis-〔(triethoxysilyl)propyl〕-disulfide, with a yield of 38.88 g and a yield of 96.05%.

[0015] Example 2: The difference between Example 2 and Example 1 is that the deep eutectic solvent is prepared, in which the molar ratio of L-menthol to thymol is 1:0.8, and the other steps are the same as those in Example 1. The specific preparation process of the deep eutectic solvent is as follows: Take 33.92 g L-menthol and 26.08 g thymol respectively, put them in a 100 mL beaker, stir at 150 rpm on a constant temperature hot plate at 70 °C for 40 min until a uniform transparent liquid is formed, transfer it to a desiccator while hot, dry it under vacuum at 60 °C for 2 h, cool and seal for later use. The yield of bis-〔(triethoxysilyl)propyl〕-disulfide prepared by Example 2 is 38.59 g, with a yield of 95.21%.

[0016] Example 3: The difference between Example 3 and Example 1 is that a deep eutectic solvent is prepared, in which the molar ratio of L-menthol to thymol is 1:1.5, and the other steps are the same as Example 1. The specific preparation process of the deep eutectic solvent is as follows: Take 24.57 g L-menthol and 35.43 g thymol respectively, put them in a 100 mL beaker, stir at 150 rpm on a constant temperature hot plate at 70 °C for 40 min until a uniform transparent liquid is formed, transfer it to a desiccator while hot, dry it under vacuum at 60 °C for 2 h, cool and seal for later use. The yield of bis-〔(triethoxysilyl)propyl〕-disulfide prepared by Example 3 is 38.82 g, with a yield of 95.90%.

[0017] Example 4: 1. Preparation of deep eutectic solvent The molar ratio of L-menthol to thymol is 1:1. The specific preparation steps are as follows: take 50.96 g L-menthol and 49.04 g thymol respectively, put them in a 200 mL beaker, stir at 150 rpm on a constant temperature hot plate at 70 °C for 40 min until a uniform transparent liquid is formed, transfer it to a desiccator while hot, dry it under vacuum at 60 °C for 2 h, cool and seal for later use.

[0018] 2. Preparation of bis-〔(triethoxysilyl)propyl〕-disulfide (1) In a 1000 mL four-necked round-bottomed reaction flask equipped with a magnetic stirrer, a thermometer, a constant-pressure dropping funnel, and a spherical condenser, 300 mL of deionized water was added, and the reaction temperature was controlled at 25 °C. 24.14 g of anhydrous sodium sulfide hydrate and 3.22 g of sulfur powder were added to the reaction flask, and stirring was carried out at 180 rpm for 35 min. (2) Take another 200 mL beaker, weigh 48.4 g of 3-chloropropyl triethoxysilane and 48.4 g of pre-dried deep eutectic solvent into the beaker, heat and stir slowly at 30 °C for 10 min until the 3-chloropropyl triethoxysilane is completely dissolved, and a uniform transparent mixed solution is obtained; (3) The temperature of the reaction bottle was heated to 35°C, and the mixed solution obtained in step (2) was added at a constant rate through a constant pressure dropping funnel. The dropping time was controlled for 40 min. After the dropping was completed, the temperature of the system was slowly increased to 42°C, and the reaction was continued for 1.8 h under the condition of 180 rpm stirring. During the reaction, a small amount of sample of the upper organic phase was taken every 30 min, diluted with n-hexane, and then analyzed by gas chromatography to monitor the residual mass fraction of 3-chloropropyltriethoxysilane. When the mass fraction was less than 0.5% and there was no obvious peak of the mercapto silane intermediate, it was determined that the reaction was completed; (4) After the reaction was completed, the heating was stopped, and the system was naturally cooled to room temperature. The water phase and the organic phase were separated by standing for 30 min. The organic phase was washed with saturated sodium chloride solution for 3 times, 50 mL each time, and then dried with anhydrous sodium sulfate for 30 min. The drying agent was removed by filtration, and the same volume of toluene as the filtrate was added to the filtrate. The reagent was concentrated under reduced pressure at 50°C and 80 rpm, and then distilled under short-path reduced pressure at 100°C and 1 mbar to obtain a light yellow transparent liquid, which was bis-〔(triethoxysil)propyl〕-disulfide, with a yield of 37.28 g and a yield of 96.39%.

[0019] Example 5: The molar ratio of L-menthol to thymol was 1:1. Specifically, 50.96 g of L-menthol and 49.04 g of thymol were weighed into a 200 mL beaker, stirred at 150 rpm on a constant temperature hot plate at 70°C for 40 min until a uniform transparent liquid was formed, transferred to a desiccator while hot, vacuum dried at 60°C for 2 h, and then cooled and sealed for use.

[0020] 2. Preparation of bis-〔(triethoxysil)propyl〕-disulfide: (1) In a 1000 mL four-necked round-bottomed reaction bottle equipped with a magnetic stirrer, a thermometer, a constant pressure dropping funnel, and a spherical condenser, 300 mL of deionized water was added, and the reaction temperature was controlled at 30°C. 28.97 g of anhydrous sodium sulfide hydrate and 3.87 g of sulfur powder were sequentially weighed into the reaction bottle, and stirred at 200 rpm for 40 min. (2) Another 200 mL beaker was taken, 48.4 g of 3-chloropropyltriethoxysilane and 72.6 g of pre-dried deep eutectic solvent were weighed into the beaker, heated and slowly stirred at 30°C for 10 min until the 3-chloropropyltriethoxysilane was completely dissolved, and a uniform transparent mixed solution was obtained; (3) The temperature of the reaction bottle was heated to 35°C, and the mixed solution obtained in step (2) was added at a constant rate through a constant pressure dropping funnel, and the dropping time was controlled for 50 min; after the dropping was completed, the temperature of the system was slowly increased to 42°C, and the reaction was continued for 2 h at 200 rpm, and every 30 min, a small amount of sample of the upper organic phase was taken, diluted with n-hexane, and analyzed by gas chromatography to monitor the residual mass fraction of 3-chloropropyl triethoxysilane, and when the mass fraction was less than 0.5% and there was no obvious peak of mercaptosilane intermediate, the reaction was determined to be completed; (4) After the reaction was completed, the heating was stopped, and the system was naturally cooled to room temperature, and the water phase and the organic phase were separated by standing for 40 min, and the organic phase was washed with saturated sodium chloride solution for 3 times, 50 mL each time, and then dried with anhydrous sodium sulfate for 30 min, and the drying agent was removed by filtration, and the same volume of toluene as the filtrate was added to the filtrate, and the reagent was concentrated under reduced pressure at 50°C and 80 rpm, and then short-path vacuum distillation was carried out at 100°C and 1 mbar, and a light yellow transparent liquid was obtained, which was bis-〔(triethoxysil) propyl〕-disulfide, with a yield of 39.46 g and a yield of 97.48%.

[0021] Comparative Example 1 In a 1000 mL four-necked round-bottom reaction bottle equipped with a magnetic stirrer, a thermometer, a constant pressure dropping funnel, and a spherical condenser, 19.2 g of sodium hydrosulfide and 7.6 g of sulfur powder were weighed, and then 300 mL of deionized water was added, and the reaction temperature was controlled at 25°C, and stirred at 180 rpm for 30 min, and 5.52 g of tetrabutylammonium chloride was added, and stirred at 180 rpm for 10 min; then 48.6 g of 3-chloropropyl triethoxysilane was slowly added in three portions, and the reaction temperature was controlled at 30°C, and stirred at 180 rpm for 3 h, and continuously monitored by gas chromatography, and samples were taken every 30 min, and until the 3-chloropropyl triethoxysilane was completely consumed; after the 3-chloropropyl triethoxysilane was consumed, the temperature was lowered to 15°C, deionized water was added, and the two phases were separated by standing for 20 min, and the organic phase was extracted with 30 mL of ethyl acetate for three times, and the organic phase was combined and cooled to -15°C, and filtered and dried with anhydrous sodium sulfate, and the organic phase was concentrated under reduced pressure at 90°C and 80 rpm to obtain a light yellow transparent liquid, which was the product bis-〔(triethoxysil) propyl〕-disulfide, with a yield of 34.26 g and a yield of 84.30%.

[0022] Comparative Example 2 In a 1000 mL four-necked round-bottom flask equipped with a magnetic stirrer, a thermometer, a constant pressure dropping funnel, a spherical condenser, 19.2 g of sodium hydrosulfide and 7.6 g of sulfur powder were weighed and added into 300 mL of deionized water, the reaction temperature was controlled at 25 °C, and stirred at 180 rpm for 30 min, then 6.4 g of tetrabutylammonium bromide was added and stirred at 180 rpm for 10 min; then 48.6 g of 3-chloropropyltriethoxysilane was slowly added in three portions, the reaction temperature was controlled at 30 °C, and stirred at 180 rpm for 3 h, continuously monitored by gas chromatography until the complete consumption of 3-chloropropyltriethoxysilane; after the complete consumption of 3-chloropropyltriethoxysilane, the temperature was lowered to 15 °C, deionized water was added, and the two phases were allowed to separate for 20 min, the organic phase was extracted with 30 mL of ethyl acetate for three times, the organic phases were combined and cooled to -15 °C, filtered and dried with anhydrous sodium sulfate, and the organic phase was concentrated under reduced pressure at 90 °C and 80 rpm to obtain a light yellow transparent liquid, which was the product bis-〔(triethoxysilyl)propyl〕-disulfide, the yield was 34.59 g, and the yield was 85.11%.

[0023] Comparative Example 3 In a 1000 mL four-necked round-bottom flask equipped with a magnetic stirrer, a thermometer, a constant pressure dropping funnel, a spherical condenser, 19.2 g of sodium hydrosulfide and 7.6 g of sulfur powder were weighed and added into 300 mL of deionized water, the reaction temperature was controlled at 25 °C, and stirred at 180 rpm for 30 min, then 6.4 g of tetrabutylammonium bromide was added and stirred at 180 rpm for 10 min; then 48.6 g of 3-chloropropyltriethoxysilane was slowly added in three portions, the reaction temperature was controlled at 30 °C, and stirred at 180 rpm for 3 h, continuously monitored by gas chromatography until the complete consumption of 3-chloropropyltriethoxysilane; after the complete consumption of 3-chloropropyltriethoxysilane, the temperature was lowered to 15 °C, deionized water was added, and the two phases were allowed to separate for 20 min, the organic phase was extracted with 30 mL of ethyl acetate for three times, the organic phases were combined and cooled to -15 °C, filtered and dried with anhydrous sodium sulfate, and the organic phase was concentrated under reduced pressure at 90 °C and 80 rpm to obtain a light yellow transparent liquid, which was the product bis-〔(triethoxysilyl)propyl〕-disulfide, the yield was 34.59 g, and the yield was 85.11%.

[0024] Sample purity detection Gas chromatography was used, an Agilent 7890A gas chromatograph was used, equipped with an FID detector, the chromatographic column was Agilent HP-5 (30 m × 0.32 mm × 0.25 μm), the carrier gas was high-purity nitrogen, the injection volume was 1 μL, and the flow rate was 1.0 mL / min to determine the purity of each example and comparative example.

[0025] The density of each example and comparative example product was determined according to GB / T 472-2011 "Determination of density, relative density of chemical products" by measuring the density of the liquid using the density bottle method.

[0026] Sulfur content detection of sample 0.10 g of the liquid sample was weighed and taken up with a pipette onto a pre-dried quantitative filter paper, so that the sample was uniformly dispersed in the center of the filter paper. After the filter paper was naturally dried, the filter paper bundle containing the sample was hung in the center of a 500 mL oxygen bomb. 10 mL of 0.1 mol / L sodium hydroxide solution and 1 mL of 30% hydrogen peroxide solution were pre-added to the bomb, the oxygen bomb was sealed, and high-purity oxygen was filled into the bomb to a pressure of 0.5 MPa. After confirming that there was no gas leakage, the filter paper was burned by an electronic ignition device; after the burning was completed, the oxygen bomb was cooled to room temperature for 30 min, and then the pressure was slowly released and the cap was opened. The inner wall, ignition cap and accessories of the oxygen bomb were thoroughly rinsed with a small amount of distilled water and combined with the absorption solution in a 100 mL conical flask. 2 mL of 30% hydrogen peroxide solution was added dropwise to the conical flask, and it was left to stand for 5 min. Then 2 mL of 5% N,N-dimethyl-p-phenylenediamine hydrochloride solution was added, and the reaction was allowed to stand for 5 min. Then 2 mL of 0.5% potassium ferricyanide solution was added, and the blue-green complex formed was allowed to develop color. The absorbance was measured at 665 nm using a UV-visible spectrophotometer. A series of 0-50 μg / mL sodium sulfate solutions were prepared to obtain a standard curve, and the sulfur content in bis-〔(triethoxysilyl)propyl〕-disulfide was calculated.

[0027] The product purity, density, sulfur content, yield and yield of Examples 1-5 and Comparative Examples 1-3 were detected, and the results are shown in Table 1.

[0028] Table 1 Performance detection results of compounds prepared in each example and comparative example As can be seen from the results in Table 1, the bis-〔(triethoxysilyl)propyl〕-disulfide obtained in Examples 1-5 is superior to Comparative Examples 1-3 in terms of purity, and the yield and yield are also significantly improved. Among them, the results of Example 5 are particularly significant, and the product purity and yield are significantly better than Examples 1-4, indicating that the ratio used in this example is more reasonable, which is beneficial to the efficient preparation of the target product.

[0029] The above description is only the preferred embodiment of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A new process for the aqueous phase synthesis of bis-〔(triethoxysilyl)propyl〕-disulfide, characterized in that, The method comprises the following steps: (1) adding deionized water into a reaction container, and then adding anhydrous sodium sulfide hydrate and sulfur powder into the reaction container in sequence, and stirring and performing temperature control reaction; (2) respectively weighing 3-chloropropyltriethoxysilane and deep eutectic solvent, and stirring to obtain a mixed solution, wherein the mass ratio of the 3-chloropropyltriethoxysilane to the deep eutectic solvent is 1:(1.1-1.5), the deep eutectic solvent is L-menthol and thymol, and the molar ratio of the L-menthol to the thymol is 1:(0.8-1.5); (3) dropping the mixed solution prepared in the step (2) into the reaction container in the step (1), controlling the dropping time, and monitoring the reaction completion through gas chromatography when the mass fraction of residual 3-chloropropyltriethoxysilane is less than 0.5%; (4) after the reaction completion is monitored in the step (3), stopping heating, cooling to room temperature, and standing and separating; taking an organic phase, washing the organic phase with saturated sodium chloride solution three times, drying the organic phase with anhydrous sodium sulfate, adding toluene with the same volume as the filtrate, and respectively performing vacuum concentration and short-path distillation to obtain the (bis-((triethoxysilyl)propyl]-disulfide.

2. The novel process for aqueous phase synthesis of bis-〔(triethoxysilyl)propyl〕-disulfide as claimed in claim 1 wherein, The molar ratio of the 3-chloropropyltriethoxysilane, the anhydrous sodium sulfide hydrate and the sulfur powder is 2:(1-1.2):(1-1.2).

3. The novel process for aqueous phase synthesis of bis-〔(triethoxysilyl)propyl〕-disulfide as claimed in claim 1 wherein, The reaction temperature of the temperature control reaction in the step (1) is 20-40°C, and the reaction time is 30-40 minutes.

4. The novel process for aqueous phase synthesis of bis-〔(triethoxysilyl)propyl〕-disulfide as claimed in claim 1 wherein, The dropping time of the mixed solution prepared in the step (2) into the reaction container in the step (1) is 30-50 minutes, and the stirring speed is 150-200 rpm, and the reaction time is 1.5-2 hours.

5. The novel process for aqueous phase synthesis of bis-〔(triethoxysilyl)propyl〕-disulfide as claimed in claim 1 wherein, The standing and separating time in the step (4) is 20-40 minutes, the vacuum concentration condition is 50°C and 80 rpm, and the short-path vacuum distillation condition is 100°C and 1 mbar.

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