A kind of preparation process of dimethyl silicone oil

Abstract

The present invention is a preparation process of dimethyl silicone oil. A preparation process of dimethyl silicone oil is: using octamethylcyclotetrasiloxane as a raw material and hexamethyldisiloxane as a capping agent, and preparing dimethyl silicone oil under the catalytic conditions of a solid acid catalyst and metal ions. The preparation process of dimethyl silicone oil described in the present invention improves the activation performance of the catalyst after using a solid acid catalyst in combination with iron ions, thereby increasing the output of dimethyl silicone oil under the premise of the same amount of catalyst.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical industry, and in particular relates to a preparation process of dimethyl silicone oil. Background Art

[0002] Dimethicone oil varies in appearance from colorless transparent volatile liquid to extremely high viscosity liquid or silica gel, depending on the relative molecular mass. It is odorless, highly transparent, and has properties such as heat resistance and cold resistance. Dimethicone oil is classified into different types according to its kinematic viscosity. It is used in pharmaceutical preparation, water repellent, anti-adhesive agent, lubricant, release agent, defoaming agent, and is also a component of emulsion or cream base.

[0003] At present, the production of dimethyl silicone oil uses organic silicon octamethylcyclotetrasiloxane as raw material. Under the catalytic conditions of solid acid catalyst, after cracking tetramethylcyclotetrasiloxane, the silicon and oxygen undergo linear rearrangement, and then hexamethyldisiloxane is used as a capping agent for preparation. However, after the solid acid catalyst has been used for a period of time, due to some structural characteristics of the solid acid catalyst, the polymerized linear polysiloxane will block the catalyst exchange channel, making it impossible to exchange catalysis, causing catalyst deactivation, affecting the polymerization effect, and reducing the output of dimethyl silicone oil.

[0004] In view of this, the present invention proposes a new preparation process of dimethyl silicone oil, which uses a solid acid catalyst in combination with metal ions to improve the yield of dimethyl silicone oil. Summary of the invention

[0005] The purpose of the present invention is to provide a preparation process of dimethyl silicone oil, which improves the activation performance of the catalyst and the output of dimethyl silicone oil by using a solid acid catalyst in combination with metal ions.

[0006] In order to achieve the above purpose, the technical solution adopted is:

[0007] The invention discloses a preparation process of dimethyl silicone oil, which comprises the following steps: using octamethylcyclotetrasiloxane as a raw material and hexamethyldisiloxane as a capping agent, and preparing the dimethyl silicone oil under the catalytic conditions of a solid acid catalyst and metal ions.

[0008] Furthermore, the preparation process is as follows: after octamethylcyclotetrasiloxane, hexamethyldisiloxane, a solid acid catalyst and metal ions are mixed and reacted, low molecular weight substances are removed to obtain the dimethyl silicone oil.

[0009] Furthermore, the solid acid catalyst is a sulfonic acid type solid acid catalyst.

[0010] Furthermore, the metal ions are iron ions.

[0011] Furthermore, the iron ions are present in an iron salt solution, and the concentration of the iron ions is 1000 mg / L.

[0012] Furthermore, the iron salt is one of ferric chloride, ferrous chloride and ferric nitrate;

[0013] The mass ratio of the solid acid catalyst to the iron salt solution is 28-32:0.001.

[0014] Furthermore, the iron salt is ferric nitrate;

[0015] The mass ratio of the solid acid catalyst to the iron salt solution is 30:0.001.

[0016] Furthermore, the temperature of the mixed reaction is 150-155° C. and the time is 0.5 h.

[0017] Furthermore, in the preparation process, low molecular weight substances are removed at 170-180° C. and a vacuum pressure of -0.01--0.03 MPa.

[0018] Furthermore, in the preparation process, low molecular weight substances are removed at 175° C. and a vacuum pressure of minus 0.02 MPa.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. The preparation process of dimethyl silicone oil described in the present invention improves the activation performance of the catalyst by using a solid acid catalyst in combination with iron ions, thereby increasing the output of dimethyl silicone oil under the premise of using the same amount of catalyst.

[0021] 2. The preparation process of dimethyl silicone oil described in the present invention adopts a solid acid catalyst in combination with iron ions, and the amount of metal ions added is very small, which has little impact on the cost and has no effect on product quality.

[0022] 3. The preparation process of the dimethyl silicone oil described in the present invention is simple. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 Schematic diagram of the device used in the preparation process of the present invention. DETAILED DESCRIPTION

[0024] In order to further illustrate the preparation process of a dimethyl silicone oil of the present invention and achieve the intended purpose of the invention, the following is a detailed description of the preparation process of a dimethyl silicone oil proposed according to the present invention, its specific implementation, structure, characteristics and efficacy in combination with the preferred embodiments. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0025] The following is a detailed description of the preparation process of a dimethyl silicone oil according to the present invention in conjunction with specific embodiments:

[0026] Aiming at the technical problem that the catalyst in the prior art of preparing dimethyl silicone oil is easy to deactivate, resulting in a decrease in the yield of dimethyl silicone oil, the present invention proposes a preparation process for dimethyl silicone oil, by adding ultra-trace amounts of iron ions to improve the activation performance of the catalyst, thereby increasing the yield of dimethyl silicone oil. The technical solution of the present invention is:

[0027] The invention discloses a preparation process of dimethyl silicone oil, which comprises the following steps: using octamethylcyclotetrasiloxane as a raw material and hexamethyldisiloxane as a capping agent, and preparing the dimethyl silicone oil under the catalytic conditions of a solid acid catalyst and metal ions.

[0028] Preferably, the preparation process is: after mixing octamethylcyclotetrasiloxane, hexamethyldisiloxane, a solid acid catalyst and metal ions for reaction, low molecular weight substances are removed to obtain the dimethyl silicone oil.

[0029] Preferably, the solid acid catalyst is an important type of acid-base catalyst. The catalytic function comes from the acidic sites with catalytic activity existing on the solid surface, called acid centers, which are formed by attaching a liquid acid to a solid carrier. The acid center in the solid acid catalyst used in the present invention is a sulfonic acid group, and the carrier is a mesoporous silicon molecular sieve.

[0030] Preferably, the metal ion is iron ion.

[0031] Further preferably, the iron ions are present in an iron salt solution, and the concentration of the iron ions is 1000 mg / L.

[0032] Further preferably, the iron salt is one of ferric chloride, ferrous chloride and ferric nitrate;

[0033] The mass ratio of the solid acid catalyst to the iron salt solution is 28-32:0.001.

[0034] Further preferably, the iron salt is ferric nitrate;

[0035] The mass ratio of the solid acid catalyst to the iron salt solution is 30:0.001.

[0036] More preferably, the temperature of the mixed reaction is 150-155° C. and the time is 0.5 h.

[0037] Further preferably, in the preparation process, low molecular weight substances are removed at 170-180° C. and a vacuum pressure of -0.01--0.03 MPa.

[0038] Further preferably, in the preparation process, low molecular weight substances are removed at 175° C. and a vacuum pressure of minus 0.02 MPa.

[0039] Example 1.

[0040] Combination Figure 1 The specific operation steps of the device shown are as follows:

[0041] (1) A solid acid catalyst (the carrier is a mesoporous silicon molecular sieve, and the acid center is a sulfonic acid group) is added to a 5L reactor, octamethylcyclotetrasiloxane with a purity greater than 99%, hexamethyldisiloxane, and an iron ion solution are added, stirring is turned on, the solid acid catalyst is evenly dispersed in the raw materials, and a reaction is carried out.

[0042] Preferably, the mass volume ratio of octamethylcyclotetrasiloxane, hexamethyldisiloxane, solid acid catalyst and iron ion solution is 3000-4000ml:25-35ml:140-160g:5mg;

[0043] The reaction temperature is 150-155°C;

[0044] The iron ion solution is one of ferric chloride, ferrous chloride and ferric nitrate solutions, and the concentration of iron ions is 1000 mg / L.

[0045] Further preferably, the mass volume ratio of octamethylcyclotetrasiloxane, hexamethyldisiloxane, solid acid catalyst and iron ion solution is 3500ml:30ml:150g:5mg;

[0046] The iron ion solution is ferric nitrate solution.

[0047] (2) After 30 minutes, take a sample and measure the viscosity.

[0048] (3) Raise the temperature to 170-180°C and control the vacuum pressure to -0.01--0.03MPa to remove low molecular weight substances (referring to unpolymerized, short-chain and other low molecular weight substances). The substances are removed from the upper part of the reactor through the low boiling point component pipeline and the cooler to the low boiling point component recovery tank. Finally, dimethyl silicone oil with a certain viscosity is obtained in the reactor.

[0049] Preferably, the low molecular weight substances are removed at 170-180° C. and a vacuum pressure of -0.01--0.03 MPa.

[0050] Example 2.

[0051] use Figure 1 The specific operation steps are as follows:

[0052] (1) In a 5L reactor, 150g of a solid acid catalyst, 3.5L of octamethylcyclotetrasiloxane with a purity greater than 99%, and 30ml of hexamethyldisiloxane were added. Stirring was started to evenly disperse the solid acid catalyst in the raw materials and react at a reaction temperature of 155°C.

[0053] After 30 minutes, a sample was taken to measure the viscosity, which was 240 mPa·s.

[0054] The temperature was raised to 175°C, and the vacuum pressure was controlled to be minus 0.02 MPa for degassing to obtain 3.3 L of dimethyl silicone oil with a viscosity of 288 mpa·s.

[0055] (2) After the dimethyl silicone oil was vented, the original solid acid catalyst was maintained, and 3.5 L of octamethylcyclotetrasiloxane with a purity greater than 99% was added, and 30 ml of hexamethyldisiloxane was added. Stirring was turned on to evenly disperse the solid acid catalyst in the raw materials and react at a reaction temperature of 155°C.

[0056] After 30 minutes, a sample was taken to measure the viscosity, which was 225 mPa·s.

[0057] The temperature was raised to 175°C and the vacuum pressure was controlled at -0.02 MPa for degassing to obtain 3.1 L of dimethyl silicone oil with a viscosity of 279 mpa·s.

[0058] (3) After the dimethyl silicone oil was emptied again, the original solid acid catalyst was maintained and 3.5 L of octamethylcyclotetrasiloxane with a purity greater than 99% was added, and 30 ml of hexamethyldisiloxane was added. The stirring was turned on to evenly stir the solid acid catalyst in the raw materials and react at a reaction temperature of 155°C.

[0059] After 30 minutes, a sample was taken to measure the viscosity, which was 195 mPa·s.

[0060] The temperature was raised to 175°C, and the vacuum pressure was controlled to -0.02 MPa for degassing to obtain 2.8 L of dimethyl silicone oil with a viscosity of 271 mpa·s.

[0061] (4) After the dimethyl silicone oil is vented, 3.5 L of octamethylcyclotetrasiloxane with a purity greater than 99% is added while maintaining the original solid acid catalyst, and 30 ml of hexamethyldisiloxane is added. Stirring is started to evenly disperse the catalyst in the raw materials and react. The reaction temperature is 155°C.

[0062] After 30 minutes, a sample was taken to measure the viscosity, which was 188 mPa·s.

[0063] The temperature was raised to 175°C, and the vacuum pressure was controlled to -0.02 MPa for degassing to obtain 2.6 L of dimethyl silicone oil with a viscosity of 275 mpa·s.

[0064] It can be seen that after the solid acid catalyst is continuously used, the yield of dimethyldichlorosilane shows a significant downward trend.

[0065] Example 3.

[0066] The specific steps are as follows:

[0067] (1) The catalyst and product in Example 1 were emptied, 150 g of the solid acid catalyst was replaced in a 5 L reactor, 3.5 L of octamethylcyclotetrasiloxane with a purity greater than 99% was added, 30 ml of hexamethyldisiloxane was added, 5 mg of iron ion solution (1000 mg / L ferric nitrate solution) was added, stirring was turned on, the solid acid catalyst was evenly dispersed in the raw materials, and the reaction was carried out at a reaction temperature of 155° C.

[0068] After 30 minutes, a sample was taken to measure the viscosity, which was 261 mPa·s.

[0069] The temperature was raised to 175°C, and the vacuum pressure was controlled to -0.02 MPa for degassing to obtain 3.4 L of dimethyl silicone oil with a viscosity of 295 mpa·s.

[0070] (2) After the dimethyl silicone oil was vented, the original solid acid catalyst was maintained, and 3.5 L of octamethylcyclotetrasiloxane with a purity greater than 99% was added, and 30 ml of hexamethyldisiloxane was added. Stirring was turned on to evenly disperse the solid acid catalyst in the raw materials and react at a reaction temperature of 155°C.

[0071] After 30 minutes, a sample was taken to measure the viscosity, which was 255 mPa·s.

[0072] The temperature was raised to 175°C, and the vacuum pressure was controlled to -0.02 MPa to obtain 3.3 L of dimethyl silicone oil with a viscosity of 289 mpa·s.

[0073] (3) After the dimethyl silicone oil was emptied again, the original solid acid catalyst was maintained and 3.5 L of octamethylcyclotetrasiloxane with a purity greater than 99% was added, and 30 ml of hexamethyldisiloxane was added. Stirring was turned on to evenly disperse the solid acid catalyst in the raw materials and react at a reaction temperature of 155°C.

[0074] After 30 minutes, a sample was taken to measure the viscosity, which was 240 mPa·s.

[0075] The temperature was raised to 175°C, and the vacuum pressure was controlled to -0.02 MPa to obtain 3.1 L of dimethyl silicone oil with a viscosity of 271 mpa·s.

[0076] (4) After continuing to vent the dimethyl silicone oil, the original solid acid catalyst was maintained, 3.5 L of octamethylcyclotetrasiloxane with a purity greater than 99% was added, 30 ml of hexamethyldisiloxane was added, stirring was turned on, the solid acid catalyst was evenly dispersed in the raw materials, and the reaction was carried out at a reaction temperature of 155°C.

[0077] After 30 minutes, the sample was taken to measure the viscosity, which was 200 mpa·s. The temperature was raised to 175°C, and the vacuum pressure was controlled to -0.02 MPa to obtain 2.8 L of dimethyl silicone oil with a viscosity of 275 mpa·s.

[0078] The production comparison results of Examples 2-3 are shown in the following table:

[0079] Table 1 Comparative data of dimethyl silicone oil production

[0080]

[0081] Note: (3.5L of octamethylcyclotetrasiloxane feed, 150g of catalyst feed)

[0082] By comparing Examples 2-3, it can be seen that under the same production process and conditions, the yield of dimethyl silicone oil is significantly increased after adding ultra-trace iron ions in the present invention. After using the new process, the output of dimethyl silicone oil can be increased by 6.8% with the same amount of catalyst.

[0083] The present invention can also obtain similar results by scaling up the feed in equal proportions.

[0084] Example 4.

[0085] The specific steps are as follows:

[0086] (1) In a 5L reactor, 140g of a solid acid catalyst, 3.0L of octamethylcyclotetrasiloxane with a purity greater than 99%, 25ml of hexamethyldisiloxane, and 5mg of an iron ion solution (1000mg / L of ferric chloride solution) were added. Stirring was started to evenly disperse the solid acid catalyst in the raw materials and react at a reaction temperature of 154°C.

[0087] (2) The reaction was completed after 30 minutes.

[0088] (3) Raising the temperature to 170° C. and controlling the vacuum pressure to -0.03 MPa to remove the residue, thereby obtaining dimethyl silicone oil.

[0089] Example 5.

[0090] The specific steps are as follows:

[0091] (1) In a 5L reactor, 160g of a solid acid catalyst, 4.0L of octamethylcyclotetrasiloxane with a purity greater than 99%, 35ml of hexamethyldisiloxane, and 5mg of an iron ion solution (1000mg / L of ferrous chloride solution) were added. Stirring was started to uniformly disperse the solid acid catalyst in the raw materials and react at a reaction temperature of 150°C.

[0092] (2) The reaction was completed after 30 minutes.

[0093] (3) Raising the temperature to 180° C. and controlling the vacuum pressure to -0.01 MPa to remove the residue, thereby obtaining dimethyl silicone oil.

[0094] The above is only a preferred embodiment of the embodiment of the present invention, and does not impose any form of limitation on the embodiment of the present invention. Any simple modification, equivalent changes and modifications made to the above embodiment based on the technical essence of the embodiment of the present invention are still within the scope of the technical solution of the embodiment of the present invention.

Claims

1. A process for preparing dimethyl silicone oil, characterized in that: The preparation process is as follows: using octamethylcyclotetrasiloxane as a raw material and hexamethyldisiloxane as a capping agent, and preparing dimethyl silicone oil under the catalytic conditions of a solid acid catalyst and metal ions; The solid acid catalyst is a sulfonic acid type solid acid catalyst; The metal ion is an iron ion; The iron ions are present in an iron salt solution, and the concentration of the iron ions is 1000 mg / L; The iron salt is one of ferric chloride, ferrous chloride and ferric nitrate; The mass ratio of the solid acid catalyst to the iron salt solution is 28-32:0.

001.

2. The preparation process according to claim 1, characterized in that: The preparation process comprises the following steps: mixing octamethylcyclotetrasiloxane, hexamethyldisiloxane, a solid acid catalyst and metal ions for reaction, and removing low molecular weight substances to obtain the dimethyl silicone oil.

3. The preparation process according to claim 1, characterized in that: The iron salt is ferric nitrate; The mass ratio of the solid acid catalyst to the iron salt solution is 30:0.

001.

4. The preparation process according to claim 2, characterized in that: The temperature of the mixed reaction is 150-155° C. and the time is 0.5 h.

5. The preparation process according to claim 2, characterized in that: In the preparation process, low molecular weight substances are removed at 170-180° C. and a vacuum pressure of minus 0.01-minus 0.03 MPa.

6. The preparation process according to claim 5, characterized in that: In the preparation process, low molecular weight substances are removed at 175° C. and a vacuum pressure of minus 0.02 MPa.

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