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CN-122011392-A - Efficient synthesis process of high-hydrogen silicone oil

CN122011392ACN 122011392 ACN122011392 ACN 122011392ACN-122011392-A

Abstract

The invention relates to the technical field of organic silicon materials, in particular to a high-efficiency synthesis process of high-hydrogen silicone oil. Firstly, mixing methyl hydrogen ring body and hexamethyldisiloxane under inert atmosphere, filtering to obtain refined raw material liquid, dispersing a specially-made magnetically-separable carbon silicon sulfonate composite solid acid catalyst in part of raw material liquid to form stable suspension, pumping the stable suspension and the rest raw material liquid into a microchannel reactor for ring-opening polymerization and equilibration reaction, and then removing low-purity by three-stage gradient vacuum. The process effectively inhibits the side reaction of Si-H bonds, realizes the efficient magnetic separation and recovery of the catalyst, and the obtained product has high hydrogen content, narrow molecular weight distribution, light color and good stability and is suitable for high-end application.

Inventors

  • ZHOU HUOSHENG
  • WANG MEILING

Assignees

  • 广东中科鸿泰新材料有限公司

Dates

Publication Date
20260512
Application Date
20260302

Claims (9)

  1. 1. The efficient synthesis process of the high-hydrogen silicone oil is characterized by comprising the following steps of: Step S1, stirring and mixing 80-95 parts by mass of methyl hydrogen ring and 5-20 parts by mass of hexamethyldisiloxane under an inert atmosphere to form a raw material premix, filtering the premix by a polytetrafluoroethylene filter membrane with the diameter of 0.15-0.25 mu m to obtain a refined raw material liquid, and storing the refined raw material liquid in a pressurized raw material tank; S2, dispersing a carbon silicon sulfonate composite solid acid catalyst in the part of the refined raw material liquid obtained in the step S1 to form a stable suspension, wherein the mass fraction of the solid acid catalyst in the stable suspension is 5% -15%, respectively, synchronously and continuously pumping the rest refined raw material liquid and the stable suspension into a Y-type static mixing unit at the front end of a micro-channel reactor according to the flow ratio of 10:1-30:1, and carrying out ring-opening polymerization and balancing reaction on the materials in the micro-channel reactor under the conditions that the temperature is 40-70 ℃ and the residence time is 10-30 min to obtain a crude product; And step S3, removing unreacted monomers and oligomers under the conditions of absolute pressure of 100-500 Pa and temperature range of 60-100 ℃ after the crude product obtained in the step S2 is subjected to magnetic separation to recover the carbon silicon sulfonate composite solid acid catalyst, so as to obtain a high-hydrogen silicone oil finished product.
  2. 2. The efficient synthesis process of the high-hydrogen silicone oil according to claim 1, wherein in the step S1, the methyl hydrogen ring is a mixture of octamethyl cyclotetrasiloxane and tetramethyl tetrahydrocyclotetrasiloxane, and the mass ratio of the tetramethyl tetrahydrocyclotetrasiloxane is 85% -95%.
  3. 3. The efficient synthesis process of the high-hydrogen silicone oil according to claim 1, wherein in the step S1, the inert atmosphere is high-purity nitrogen or argon, the water content in the gas is lower than 10ppm, the oxygen content is lower than 5ppm, and the stirring and mixing speed of the pre-mixed reaction liquid is 300-600 rpm, and the time is 10-30 min.
  4. 4. The efficient synthesis process of the high-hydrogen silicone oil according to claim 1, wherein in the step S2, the preparation method of the carbon silicon sulfonate composite solid acid catalyst comprises the following steps: Dissolving glucose, tetraethyl orthosilicate and cetyltrimethylammonium bromide (10-20) in a mass ratio of (0.35-0.70) in an ethanol-water mixed solvent, stirring for 12-24 hours at 60-80 ℃, carrying out synchronous hydrothermal carbonization and silica sol-gel process, transferring the mixture to a high-pressure reaction kettle, carrying out hydrothermal reaction for 6-12 hours at 180-200 ℃, cooling, centrifuging, washing and drying to obtain a carbon/silica composite microsphere precursor; Heating the precursor prepared in the step (1) to 550-650 ℃ in an inert atmosphere, preserving heat for 4-6 hours, carbonizing and removing cetyl trimethyl ammonium bromide to form a carbon/silicon dioxide composite carrier; Dispersing the carrier prepared in the step (2) in a concentrated dichloroethane sulfate solution with the concentration of 1.0-3.0 mol/L under the protection of nitrogen and mechanical stirring, carrying out reflux reaction for 6-12 h at 60-80 ℃, carrying out sulfonation, washing with deionized water to be neutral after the reaction, and drying to obtain sulfonated carrier powder; Dispersing the sulfonated carrier powder prepared in the step (3) in ethanol, adding ferroferric oxide nano particles, stirring for 2-4 hours at 60-80 ℃ after ultrasonic dispersion is uniform, wherein the addition amount of the ferroferric oxide nano particles is 5-15% of the total mass of the final catalyst, separating a solid acid catalyst from a liquid phase through magnetic separation, and washing and drying to obtain the pure carbon silicon sulfonate composite solid acid catalyst.
  5. 5. The efficient synthesis process of the high-hydrogen silicone oil according to claim 1, wherein in the step S2, the specific surface area of the carbon silicon sulfonate composite solid acid catalyst is 500-800 m 2 /g, and the loading amount of sulfonic acid groups is 1.5-2.5 mmol/g.
  6. 6. The process for highly efficient synthesis of high-hydrogen silicone oil according to claim 1, wherein in the step S2, the microchannel reactor is made of stainless steel, the inner diameter is 0.5-2.0 mm, the channel length is 5-20 m, the operating pressure is 0.1-0.5 mpa, and the reynolds number of the reaction solution in the microchannel reactor is 100-500.
  7. 7. The efficient synthesis process of high-hydrogen silicone oil according to claim 1, wherein in the step S3, the magnetic field strength used for magnetic separation is 0.3-0.8 t, and the separation time is 2-5 min.
  8. 8. The high-efficiency synthesis process of the high-hydrogen silicone oil according to claim 1, wherein in the step S3, a low-temperature gradient stripping system is composed of three stages of short-path molecular distillers connected in series, the temperature of a first stage is 60-70 ℃ and the absolute pressure is 400-500 Pa, the temperature of a second stage is 75-85 ℃ and the absolute pressure is 300-350 Pa, the temperature of a third stage is 90-100 ℃ and the absolute pressure is 100-150 Pa, the first stage, the second stage and the third stage distillers are sequentially connected through heat preservation pipelines, a crude product automatically flows through each stage by means of pressure difference in the system, and each stage of distillers is provided with a film scraping rotor with the rotating speed of 200-400 rpm.
  9. 9. The efficient synthesis process of the high-hydrogen silicone oil according to claim 1, wherein in the step S3, an outlet of the low-temperature gradient dropping system is connected with a cold trap, and the temperature of the cold trap is-40 ℃ to-20 ℃.

Description

Efficient synthesis process of high-hydrogen silicone oil Technical Field The invention relates to the technical field of organic silicon materials, in particular to a high-efficiency synthesis process of high-hydrogen silicone oil. Background The high-hydrogen silicone oil, namely the polymethylhydrosiloxane with high active hydrogen content, is a key intermediate in an organosilicon material system, and the molecular main chain or side chain of the polymethylhydrosiloxane is rich in Si-H bonds with high reactivity, thereby playing an irreplaceable role in textile finishing agents, paper isolating agents, silicone rubber cross-linking agents, surface hydrophobic treatment and various functional organosilicon synthesis. Currently, the mainstream method for industrially synthesizing high-hydrogen silicone oil generally takes methyl hydrogen ring and end capping agent, such as hexamethyldisiloxane, as raw materials, and carries out ring-opening polymerization and equilibration reaction under the action of an acidic or alkaline catalyst. However, this conventional process faces a series of interrelated technical challenges in pursuing high efficiency, high quality and green safety production. Firstly, the chemical nature of Si-H bond is active, and under the catalysis of strong acid (such as concentrated sulfuric acid) or strong base (such as KOH) and higher temperature conditions, side reactions such as rearrangement, oxidation, hydrolysis and the like are easy to occur, which not only leads to the reduction of the hydrogen content of the target product, but also can cause the crosslinking of molecular chains to generate gel, or generate low molecular weight annular byproducts, so that the molecular weight distribution of the product is widened and the uniformity is poor. Secondly, although the traditional homogeneous catalyst has higher activity, the traditional homogeneous catalyst is difficult to thoroughly separate from a high-viscosity product, trace residues can continuously catalyze side reactions, so that the color of the product is deepened, the hydrogen content is attenuated and even gelled in the storage process, and the application performance and the stability of the product are seriously influenced. In addition, the traditional batch kettle reaction has the problems of uneven mixing, low mass and heat transfer efficiency and the like, local overheating or uneven material concentration can aggravate side reactions, and safety risks are brought, such as the reaction of Si-H bonds and trace moisture to release hydrogen. Finally, post-reaction treatments, such as distillation under reduced pressure to remove low boiling point substances, are generally high in energy consumption and long in time consumption, and the high temperature environment may further destroy Si-H bonds, thereby affecting the quality of the final product. Chinese patent publication No. CN112679736B discloses a phenyl hydrogen silicone oil and a preparation method thereof. The preparation process of phenyl hydrogen containing silicone oil includes the synthesis reaction of siloxane material and end capping agent in the presence of heteropoly acid catalyst. The heteropolyacid catalyst is prepared by loading phosphomolybdic heteropolyacid on attapulgite. By taking the heteropolyacid catalyst as the catalyst for the synthesis reaction, the phenyl hydrogen-containing silicone oil can be synthesized under mild reaction conditions, thereby being beneficial to energy conservation and consumption reduction, simultaneously, the use of a neutralizer can be avoided, the operation process is simplified, the preparation cost is reduced, and in addition, the method can also improve the yield and the quality of the phenyl hydrogen-containing silicone oil. The phenyl hydrogen-containing silicone oil obtained by the method has higher yield and lower viscosity. However, the technical scheme focuses on phenyl hydrogen-containing silicone oil, the introduced phenyl structure changes the basic physicochemical property of the product, and the general high hydrogen-containing silicone oil has differences in application scenes and performance indexes. Disclosure of Invention The invention aims to provide a high-efficiency synthesis process of high-hydrogen silicone oil, which aims to solve the problems that Si-H bonds are easily damaged, a product is unstable due to catalyst residues and the mass and heat transfer efficiency is low in the reaction process in the traditional high-hydrogen silicone oil synthesis process provided by the background technology. In order to achieve the above purpose, the present invention provides the following technical solutions: an efficient synthesis process of high-hydrogen silicone oil comprises the following steps: Step S1, stirring and mixing 80-95 parts by mass of methyl hydrogen ring and 5-20 parts by mass of hexamethyldisiloxane at 25-35 ℃ in an inert atmosphere to form a raw material premix, filtering the premix b