Device for preparing hydroxyl silicone oil by using micro-channel reactor

Abstract

The utility model discloses a device for preparing hydroxyl silicone oil by using a micro-channel reactor, which is characterized in that a dimethyldichlorosilane storage tank and a hydrolysis medium storage tank are respectively connected with the micro-channel reactor through a first peristaltic pump and a second peristaltic pump, the discharge end of the micro-channel reactor is connected with a phase separator, and the upper part of the phase separator is connected with a falling film evaporator; the falling film evaporator is connected with the vacuum separator through a pipeline and then is connected with the hydroxyl silicone oil storage tank; by utilizing the excellent mass transfer and heat exchange performance of the micro-channel reactor, not only is the reaction time greatly shortened, but also compared with the traditional kettle reaction, the drop-by-drop feeding loss and the risk that the raw material dimethyldichlorosilane and the hydrolysis medium are subjected to violent hydrolysis reaction to release heat and are easy to spray are reduced, and the production efficiency is improved. And the method has the advantages of high efficiency, energy conservation, easiness in control, few three wastes and the like.

Description

Technical Field

[0001] The utility model belongs to the technical field of organic silicon synthesis, and particularly relates to a device for preparing hydroxy silicone oil by utilizing a microchannel reactor. Background Art

[0002] Currently, the main process for producing hydroxy silicone oil is to react dimethylcyclosiloxane with acetic anhydride under acidic catalyst conditions to first synthesize acetoxy-terminated silicone oil, then use water to remove the acidic catalyst, neutralize and hydrolyze with Na2CO3 or NaHCO3 to neutrality, remove water, and decolorize to obtain hydroxy silicone oil. This method has low conversion rate and high cost. Hydrolysis of dimethyldichlorosilane with ammonia to prepare hydroxy silicone oil has high hydroxyl content, high conversion rate, and low cost. CN 116589683A patent discloses the use of ammonia for hydrolysis, but due to insufficient hydrolysis in this process, the hydroxy silicone oil obtained by hydrolysis has a relatively low hydroxyl content.

[0003] Patent CN 109942820A discloses methylphenyl hydroxy silicone oil, but the obtained hydroxyl content is only 3-5%.

[0004] In the process of hydrolysis using alkali, the hydrolysis is carried out in a conventional pipeline or kettle reactor. Since the reaction is extremely rapid, the dimethyl raw material will dissolve into the prepared hydroxy silicone oil product, continue to react, and cause the hydroxyl group to continue to condense, resulting in incomplete hydrolysis. Summary of the Invention

[0005] In response to the above technical problems, the utility model provides a process for hydrolyzing dimethyldichlorosilane and ammonia water using a microchannel reactor, which effectively controls the degree of violent reaction of dimethyldichlorosilane and ammonia water, makes the hydrolysis reaction more complete, and obtains hydroxy silicone oil.

[0006] This new method utilizes a microchannel reactor with high mass and heat transfer performance and a unique microstructure to effectively control the concentration distribution of the hydrolysis medium, resulting in efficient mixing of materials during the reaction. Furthermore, it addresses safety issues associated with traditional kettle-type reactions, such as cumbersome operation, difficult temperature control, and the tendency for material spraying during the hydrolysis of the raw material dimethyldichlorosilane.

[0007] A device for preparing hydroxy silicone oil using a microchannel reactor, wherein a dimethyldichlorosilane storage tank and a hydrolysis medium storage tank are connected to the microchannel reactor via a first peristaltic pump and a second peristaltic pump respectively; the discharge end of the microchannel reactor is connected to a phase separator; the upper part of the phase separator is connected to a falling film evaporator; the falling film evaporator is connected to a vacuum separator via a pipeline and then to the hydroxy silicone oil storage tank.

[0008] A back pressure valve is provided at the rear end of the microchannel reactor.

[0009] The discharge end of the microchannel reactor is connected to the slurry mixing tank via a back pressure valve, and the slurry mixing tank is connected to the phase separator.

[0010] The bottom of the phase separator is connected to the ammonium chloride liquid phase storage tank.

[0011] The microchannel reactor is a Corning Microchannel special glass reactor with a heart-shaped microchannel and heat exchange plate layers on both the upper and lower surfaces.

[0012] The method for preparing hydroxy silicone oil using the above-mentioned device includes the steps of microchannel hydrolysis reaction:

[0013] Pumping dimethyldichlorosilane and a hydrolysis medium into a microchannel reactor respectively for hydrolysis reaction, and adjusting the reaction pressure in the microchannel reactor;

[0014] After the reaction is completed, the reaction liquid is separated into a hydrolyzate and an aqueous medium containing ammonium chloride through a phase separator;

[0015] The hydrolysis product is removed and hydroxy silicone oil is obtained.

[0016] The reaction formula is as follows:

[0017]

[0018] In some embodiments, the flow rates of dimethyldichlorosilane and the hydrolysis medium are 0.1-10.0 mL / min and 20-100.0 mL / min, respectively.

[0019] As a preferred embodiment, the flow rates of the dimethyldichlorosilane and the hydrolysis medium are 1.0-5.0 mL / min and 20-50.0 mL / min, respectively.

[0020] The hydrolysis medium is aqueous ammonia, and the mass concentration of the aqueous ammonia is 5-30%, preferably 15-30%.

[0021] The hydrolysis medium further contains ammonium salt, so that the ammonia water and the ammonium salt form a mixture, wherein the concentration of the ammonium salt is 10-35%, preferably 15-30%.

[0022] The concentration of ammonia plays a key role in the microchannel reaction. If the ammonia concentration is too low, such as less than 5%, the acid absorption will be insufficient, and the hydroxyl groups of the hydroxyl silicone oil will be lost; if the ammonia concentration is too high, such as higher than 30%, the alkalinity will be too high and the hydroxyl groups of the hydroxyl silicone oil will be lost.

[0023] The ammonium salt is selected from any one or more combinations of ammonium chloride, ammonium sulfate, ammonium nitrate, ammonium carbonate, and ammonium bicarbonate.

[0024] In this case, the addition of ammonium salt increases the density of the aqueous phase in the hydrolysis reaction, so that the oil phase of the hydrolysis product obtained during the hydrolysis reaction is separated from the aqueous phase.

[0025] However, if the salt concentration is too high, the microchannel may be blocked due to its high density, and if the salt concentration is too low, the oil-water separation will not be complete.

[0026] The back pressure valve adjusts the reaction pressure in the microchannel reactor to 0.1-0.5 MPa, preferably 0.3-0.4 MPa; the reaction temperature is controlled to 0°C~50°C, preferably 0°C~30°C.

[0027] At this temperature and pressure, dimethyldichlorosilane and the hydrolysis medium are fully mixed and react smoothly. If the temperature is too high under alkaline conditions, hydroxyl groups are easily lost.

[0028] The residence time in the microchannel is 1-20s, preferably 1-10s. The microchannel reactor is a microchannel reactor selected from Corning specialty glass reactors, with heart-shaped microchannels, heat exchange plate layers on both the upper and lower surfaces, and chilled water as the medium in the layer, and an external heat exchanger is used to achieve the set temperature control, and the glass reactor is selected from Shinwell.

[0029] The liquid holding capacity in the reaction coil is 50-90% of the coil volume, more preferably 50-80%.

[0030] The hydrolysis reaction is a violent reaction process. The liquid holding conditions in the process will make the reaction proceed violently in the microchannel, further realizing the full progress of the hydrolysis.

[0031] Using the technical solution, the prepared hydroxyl silicone has a linear to ring ratio of ≥9:1, a hydroxyl content of 8-14%, and a viscosity of 28-40cp. More preferably, the obtained hydroxyl silicone oil has a linear to ring ratio of 9:1 to 95:5, and more preferably, the obtained hydroxyl silicone oil has a linear to ring ratio of 9:1 and 19:1:45:1. More preferably, the hydroxyl content is 10-14%, and even more preferably, the hydroxyl content is 12-14%.

[0032] The microchannel reactor and hydrolysis process of the utility model eliminate the acidity of the dimethyl dichloride material in the intermittent process, and weaken the influence of the alkalinity of ammonia in the reaction solution on the hydroxyl content of the hydroxyl silicone oil product, thereby avoiding the problem of easy polycondensation between hydroxyl groups in the obtained hydroxyl silicone oil product due to excessive hydroxyl content, and stabilizing the hydroxyl content of the product.

[0033] The utility model provides a device for preparing hydroxyl silicone oil using a microchannel reactor. In this device, dimethyldichlorosilane is used as the starting material and the hydroxyl silicone oil is synthesized using a microchannel reactor. Subsequently, the raw materials and the hydrolysis medium are fed sequentially through a pipeline reactor. After the reaction is completed, the hydroxyl silicone oil is obtained through oil-water separation, evaporation using a falling film evaporator, and vacuum separation. In the synthesis of the hydroxyl silicone oil provided by the utility model, the use of a microchannel reactor shortens the reaction time and increases the reaction rate. In addition, the safety risks caused by the hydrolysis exothermic reaction are greatly reduced.

[0034] Hydrolysis of dimethyldichlorosilane with ammonia water to prepare hydroxy silicone oil has high hydroxyl content, high conversion rate and low cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0036] Figure 1 This is a simplified structural diagram of the preparation of hydroxy silicone oil using a microchannel reactor.

[0037] Dimethyldichlorosilane storage tank 1, hydrolysis medium storage tank 2, first peristaltic pump 10-1, second peristaltic pump 10-2, microchannel reactor 3, slurry mixing tank 4, phase separator 5, falling film evaporator 6, vacuum separator 7, hydroxy silicone oil storage tank 8, ammonium chloride liquid phase storage tank 9, back pressure valve 10.

[0038] Figure 2 This is the infrared image of the product obtained in Example 2. DETAILED DESCRIPTION

[0039] The present invention will be further described below with reference to the embodiments. However, the scope of protection claimed by the present invention is not limited to the scope described in the embodiments.

[0040] The hydroxyl content detection conditions in this utility model are: gas quantification method, which uses lithium aluminum hydride to convert the active hydrogen on the hydroxyl group into hydrogen gas, and measures the volume of hydrogen gas to calculate the amount of hydroxyl group. This is thermal gravimetric characterization.

[0041] The viscosity content detection conditions in the present invention are: using a Brookfield DVNext rotary viscometer, and the measurement is carried out at 25°C.

[0042] Example 1

[0043] An apparatus for preparing hydroxyl silicone oil using a microchannel reactor. A dimethyldichlorosilane storage tank 1 and a hydrolysis medium storage tank 2 are connected to a microchannel reactor 3 via a first peristaltic pump 10-1 and a second peristaltic pump 10-2, respectively. The microchannel reactor 3 is connected to a slurry mixing tank 4, which is then connected to a phase separator 5. The upper portion of the phase separator 5 is connected to a falling film evaporator 6. The falling film evaporator 6 is connected via a pipeline to a vacuum separator 7, which is then connected to a hydroxyl silicone oil storage tank 8. A back pressure valve 10 is provided at the rear end of the microchannel reactor 3. The bottom of the phase separator 5 is connected to an ammonium chloride liquid phase storage tank 9. Microchannel reactor 3 is a Corning Microchannel G1 glass reactor with heart-shaped microchannels and heat exchange plate layers on both the top and bottom surfaces. The Corning Microchannel G1 was purchased from Beijing Obel Scientific Instrument Co., Ltd.

[0044] Example 2

[0045] The following process is carried out using the device of Example 1

[0046] A method for preparing hydroxy silicone oil using a microchannel reactor, comprising: pumping dimethyldichlorosilane and a hydrolysis medium (the hydrolysis medium contains 19 wt% ammonia water) into the microchannel reactor via a peristaltic pump at flow rates of 20.0 mL / min and 100.0 mL / min, respectively, for a hydrolysis reaction; adjusting the reaction pressure in the microchannel reactor to 0.1 MPa via a back pressure valve, and controlling the temperature to 10°C; the liquid holdup of the reaction coil is 80% of the coil volume, and the residence time is 10 seconds;

[0047] After the reaction is completed, the reaction liquid is separated into a hydrolyzate and an aqueous medium containing ammonium chloride in a phase separator;

[0048] The hydrolysis product is then subjected to impurity removal to obtain hydroxy silicone oil. The impurity removal step includes evaporating water and ammonia using a falling film evaporator and separating unavoidable color (such as rust) to obtain the hydroxy silicone oil. The linear to ring ratio is 11:1, the hydroxyl content is 10.5%, and the viscosity is 30 cp.

[0049] from Figure 2 It can be seen that the hydroxy silicone oil prepared in Example 2 has a -1 There is an obvious hydroxyl peak.

[0050] Example 3

[0051] The following process is carried out using the device of Example 1

[0052] A method for preparing hydroxy silicone oil using a microchannel reactor, comprising: pumping dimethyldichlorosilane and a hydrolysis medium (the hydrolysis medium contains 15 wt% ammonia water and 10 wt% ammonium chloride) into a microchannel reactor via a peristaltic pump at flow rates of 5.0 mL / min and 20.0 mL / min, respectively, for a hydrolysis reaction. The reaction pressure in the microchannel reactor is adjusted to 0.1 MPa via a back pressure valve, and the temperature is controlled at 10°C. The liquid holdup of the reaction coil is 80% of the coil volume, and the residence time is 5 seconds.

[0053] After the reaction is completed, the reaction liquid is separated into a hydrolyzate and an aqueous medium containing ammonium chloride through a phase separator;

[0054] The hydrolysis product is then subjected to impurity removal to obtain hydroxy silicone oil. This impurity removal step involves removing water and ammonia through a falling film evaporator and separating out unavoidable color (such as rust) to obtain the hydroxy silicone oil. The hydroxy silicone oil has a linear to linear ratio of 19:1, a hydroxyl content of 11.9%, and a viscosity of 33 cp.

[0055] Example 4

[0056] The following process is carried out using the device of Example 1

[0057] A method for preparing hydroxy silicone oil using a microchannel reactor, comprising: pumping dimethyldichlorosilane and a hydrolysis medium (the hydrolysis medium contains 25 wt% ammonia water and 26 wt% ammonium sulfate) into a microchannel reactor via a peristaltic pump at flow rates of 10.0 mL / min and 60.0 mL / min, respectively, for a hydrolysis reaction. The reaction pressure in the microchannel reactor is adjusted to 0.1 MPa via a back pressure valve, and the temperature is controlled at 10°C. The liquid holdup of the reaction coil is 80% of the coil volume, and the residence time is 4 seconds.

[0058] After the reaction is completed, the reaction liquid is separated into a hydrolyzate and an aqueous medium containing ammonium chloride through a phase separator;

[0059] The hydrolysis product is then subjected to impurity removal to obtain hydroxy silicone oil. This impurity removal step involves removing water and ammonia via a falling film evaporator and separating out unavoidable color (such as rust) to obtain the hydroxy silicone oil. The hydroxy silicone oil has a linear to linear ratio of 37:1, a hydroxyl content of 13.1%, and a viscosity of 34 cp.

[0060] Example 5

[0061] The following process is carried out using the device of Example 1

[0062] A method for preparing hydroxy silicone oil using a microchannel reactor, comprising: pumping dimethyldichlorosilane and a hydrolysis medium (the hydrolysis medium contains 19 wt% ammonia water and 28 wt% ammonium sulfate) into a microchannel reactor via a peristaltic pump at flow rates of 20.0 mL / min and 100.0 mL / min, respectively, for a hydrolysis reaction. The reaction pressure in the microchannel reactor is adjusted to 0.1 MPa via a back pressure valve, and the temperature is controlled at 10°C. The liquid holdup of the reaction coil is 80% of the coil volume, and the residence time is 5 seconds.

[0063] After the reaction is completed, the reaction liquid is separated into a hydrolyzate and an aqueous medium containing ammonium chloride through a phase separator;

[0064] The hydrolysis product is then subjected to impurity removal to obtain hydroxy silicone oil. This impurity removal step involves removing water and ammonia through a falling film evaporator and separating out unavoidable color (such as rust) to obtain the hydroxy silicone oil. The hydroxy silicone oil has a linear to linear ratio of 41:1, a hydroxyl content of 13.2%, and a viscosity of 32 cp.

[0065] Example 6

[0066] The following process is carried out using the device of Example 1

[0067] A method for preparing hydroxy silicone oil using a microchannel reactor, comprising: pumping dimethyldichlorosilane and a hydrolysis medium (the hydrolysis medium contains 30 wt% ammonia water and 18 wt% ammonium carbonate) into a microchannel reactor via a peristaltic pump at flow rates of 2.0 mL / min and 40.0 mL / min, respectively, for a hydrolysis reaction. The reaction pressure in the microchannel reactor is adjusted to 0.1 MPa via a back pressure valve, and the temperature is controlled at 10°C. The liquid holdup of the reaction coil is 80% of the coil volume, and the residence time is 3 seconds.

[0068] After the reaction is completed, the reaction liquid is separated into a hydrolyzate and an aqueous medium containing ammonium chloride through a phase separator;

[0069] The hydrolysis product is then subjected to impurity removal to obtain hydroxy silicone oil. This impurity removal step involves removing water and ammonia via a falling film evaporator and separating and removing unavoidable color (such as rust) to obtain the hydroxy silicone oil. The hydroxy silicone oil has a linear to linear ratio of 45:1, a hydroxyl content of 13.5%, and a viscosity of 30 cp.

[0070] Comparative Example 1

[0071] A method for preparing hydroxy silicone oil involves continuously introducing dimethyldichlorosilane and aqueous ammonia (the concentration of the aqueous ammonia is 8% by weight. Due to acid-base neutralization, the concentration cannot be increased, and the reaction is too violent when the concentration exceeds 10% by weight, so it is controlled at 8% in this case) into a tank reactor for hydrolysis. The mass ratio of dimethyldichlorosilane to aqueous ammonia is 2 kg:40 kg (i.e., 1:20). The hydrolysis product is separated into an oil phase and an aqueous phase containing ammonium chloride via a phase separator. The oil phase is then cleaned of impurities to obtain the hydroxy silicone oil. The cleanup step involves removing water and ammonia by evaporation in a falling film evaporator, and removing unavoidable color (such as rust) to obtain the hydroxy silicone oil. The hydroxy silicone oil has a linear ratio of 8:2, a hydroxyl content of 6.8%, and a viscosity of 28 cp.

Claims

1. A device for preparing hydroxy silicone oil using a microchannel reactor, characterized in that: The dimethyldichlorosilane storage tank (1) and the hydrolysis medium storage tank (2) are connected to the microchannel reactor (3) via a first peristaltic pump (10-1) and a second peristaltic pump (10-2), respectively. The discharge end of the microchannel reactor (3) is connected to a phase separator (5), and the upper part of the phase separator (5) is connected to a falling film evaporator (6). The falling film evaporator (6) is connected to a vacuum separator (7) via a pipeline and then connected to a hydroxy silicone oil storage tank (8).

2. The device for preparing hydroxy silicone oil using a microchannel reactor according to claim 1, characterized in that: A back pressure valve (10) is provided at the rear end of the microchannel reactor (3).

3. The device for preparing hydroxy silicone oil using a microchannel reactor according to claim 2, characterized in that: The discharge end of the microchannel reactor (3) is connected to the slurry mixing tank (4) via a back pressure valve (10), and the slurry mixing tank (4) is connected to the phase separator (5).

4. The device for preparing hydroxy silicone oil using a microchannel reactor according to claim 2, characterized in that: The bottom of the phase separator (5) is connected to the ammonium chloride liquid phase storage tank (9).

5. The device for preparing hydroxy silicone oil using a microchannel reactor according to claim 1, characterized in that: The microchannel reactor (3) is a Corning microchannel G1 glass reactor with a heart-shaped microchannel and heat exchange plate layers on both the upper and lower surfaces.

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