Preparation method for synthesizing vinyl silsesquioxane (POSS) by microwave method

Abstract

The invention relates to a preparation method for synthesizing vinyl silsesquioxane (POSS) by a microwave method. Methyl trimethoxy silane (MTS) and vinyl trimethoxy silane (VTS) serve as raw materials, and octavinyl silsesquioxane monomers and divinyl hexamethyl silsesquioxane monomers are synthesized through a hydrolytic condensation reaction in a microwave reactor under the acidic condition. Compared with the conventional heating chemical reaction, the method for synthesizing vinyl silsesquioxane by adopting the microwave reactor has the advantages of quicker chemical reaction, high reaction yield and the like.

Description

Technical Field

[0001] The invention provides a preparation method of vinyl silsesquioxane (POSS) synthesized by microwave method, which specifically adopts a microwave reactor to synthesize octavinyl silsesquioxane monomer and divinyl hexamethyl silsesquioxane monomer through hydrolysis condensation reaction under acidic conditions. Background Art

[0002] Nanomaterials have the characteristics of small particle size, large specific surface area, high surface energy, large proportion of surface atoms, and three unique effects: surface effect, small size effect and macro quantum tunneling effect, which make them have super research value and excellent application prospects in the field of materials. Nanomaterials have been developed for decades, and there are countless nanostructures to choose from. For example, nanoparticles such as SiO2, TiO2, MgO and γ-Al2O3 are often involved in the research of oil development and application. In practical applications, the selection of nanostructures must take into account many factors. In addition to having good performance, economic cost, environmental friendliness and biocompatibility must also be considered.

[0003] Polyhedral Oligomeric Silsesquioxane (POSS) is an organic-inorganic hybrid molecule with a cage structure. Its regular stereostructure, nanometer size, good compatibility and modifiability of peripheral groups make it the most promising choice for molecular structure design. In the past 20-25 years, RSiO 3 / 2 Silsesquioxanes of compounds with repeating units have made great progress in the field of chemical research of siloxanes. These compounds have structural units in the properties of inorganic ceramic materials and organosilicon polymers at the same time, that is, inorganic Si-O-Si structural units with chemical inertness and thermal stability and R-Si structural units with potential reactivity and easy modification, so this type of molecule has the properties of organic-inorganic hybridization. POSS is considered to be a particle of siloxane with the smallest size, and its three-dimensional size Si-O-Si length is about 0.50nm, and the length between organic functional groups is about 1.5nm. According to the difference in POSS structure, POSS can be divided into regular hexahedron POSS, regular octahedron POSS, regular dodecahedron POSS and other multiples. Regular hexahedron POSS has a cage-shaped skeleton, and the constituent unit of its skeleton is Si-O-Si, which has high symmetry and good thermal stability. Different substituents can be connected at each vertex, so that it is easy to modify and obtain abundant functional groups, which can make POSS have different properties. This means that in addition to its own special molecular structure, POSS also combines the excellent properties of organic and inorganic compounds. Its easy modification characteristics make it an excellent raw material for preparing new compounds or new materials.

[0004] The invention relates to a preparation method of vinyl hexahedral silsesquioxane (POSS) synthesized by microwave method. Methyltrimethoxysilane (MTS) and vinyltrimethoxysilane (VTS) are used as raw materials, and octavinyl silsesquioxane monomer and divinyl hexamethyl silsesquioxane monomer are synthesized by hydrolysis condensation reaction under acidic conditions in a microwave reactor. Compared with conventional heating chemical reactions, the synthesis of vinyl silsesquioxane by using a microwave reactor has the advantages of faster chemical reaction, high reaction yield, etc. In addition, the raw materials of the method are easily available, the operation is convenient, and the method has great development prospects. Summary of the invention

[0005] The purpose of the present invention is to design a preparation method of vinyl silsesquioxane (POSS) synthesized by microwave method. To achieve this requirement, the present invention mainly uses methyltrimethoxysilane (MTS) and vinyltrimethoxysilane (VTS) as raw materials, and synthesizes octavinyl silsesquioxane monomer and divinyl hexamethyl silsesquioxane monomer through hydrolysis condensation reaction under acidic conditions in a microwave reactor.

[0006] The synthesis methods of various types of POSS mainly include the following steps:

[0007] The first one: Synthesis of octavinyl silsesquioxane monomer. Take a 100mL three-necked flask, use anhydrous ethanol as solvent, concentrated hydrochloric acid as catalyst, drip vinyl trimethoxysilane into the constant pressure dropping funnel, stir and heat, react in the microwave reactor for several hours, stop heating and cool to room temperature, precipitate white precipitate, indicating that the reaction is complete, filter the precipitate to obtain octavinyl silsesquioxane monomer.

[0008] The second method: Synthesis of divinyl hexamethylsilsesquioxane monomer. At 60°C, add a certain amount of a mixed solution of methyltrimethoxysilane and vinyltrimethoxysilane, use anhydrous ethanol as a solvent, stir magnetically, react in a microwave reactor for a period of time, and then white turbidity appears. Then stop the reaction within a specified time and cool to room temperature. Filter and dry to obtain a white powder product.

[0009] In the present invention, in the first preparation process, the raw material is only vinyltrimethoxysilane, the reaction time is 3h, the reaction temperature is 60°C, the microwave power is 400W, and octavinylsilsesquioxane monomer is obtained.

[0010] In the present invention, the molar ratio of methyltrimethoxysilane to vinyltrimethoxysilane in the second preparation process is 3:1, the reaction time is 4 hours, the reaction temperature is 60° C., and the microwave reaction power is 400 W. The product is filtered and dried to obtain a white powder.

[0011] The present invention is the first to use a microwave reactor to prepare vinyl silsesquioxane, and has the following outstanding advantages in the preparation process:

[0012] 1. The three-dimensional dimensions of nanoscale POSS are all within the nanoscale range. It is a typical nanocompound with nanoparticle small size effect, surface and interface effect, quantum size effect, and macroscopic quantum tunneling effect, thus having strong comprehensive performance.

[0013] 2. The hexahedral POSS has a cage-shaped skeleton, the constituent units of which are Si-O-Si, with high symmetry and good thermal stability. Different substituents can be connected to each vertex, making it easy to modify and obtain rich functional groups, thereby producing different properties.

[0014] 3. Compared with conventional heating chemical reactions, the synthesis of vinyl silsesquioxane using a microwave reactor has the advantages of faster chemical reactions and higher reaction yields. In addition, the raw materials of this method are easily available and the operation is convenient, which has great development prospects. DETAILED DESCRIPTION

[0015] The present invention is further described below by way of implementation examples, the purpose of which is to provide a better understanding of the content of the present invention.

[0016] Embodiment 1:

[0017] Synthesis of octavinyl silsesquioxane monomer. Take a 100mL three-necked flask equipped with a thermometer and a condenser, add 50mL of anhydrous ethanol, 2.15g of double distilled water and 2.23g of concentrated hydrochloric acid, mix and put into a rotor, heat and stir to 60°C, then add 2.78g of vinyl trimethoxysilane dropwise with a constant pressure dropping funnel, and after the addition is complete, transfer the three-necked flask to a microwave reactor at 400W and 60°C for 3h. After the reaction is completed, cool to room temperature and observe the three-necked flask. If a precipitate is precipitated in the three-necked flask, it means that the reaction is good. Filter and dry the precipitate to obtain the octavinyl silsesquioxane monomer.

[0018] Embodiment 2:

[0019] Synthesis of divinyl hexamethylsilsesquioxane monomer. 50 mL of anhydrous ethanol, 1.62 g of single-distilled water and 1.095 g of concentrated hydrochloric acid were added to a 100 mL three-necked flask equipped with a reflux condenser and a constant temperature heating magnetic force, respectively. After mixing, the reaction system was heated to 60°C. Using a constant pressure dropping funnel, 2.04 g of methyltrimethoxysilane and 0.74 g of vinyltrimethoxysilane were mixed in a molar ratio of 3:1 and slowly added to the three-necked flask. After the addition was completed, the three-necked flask was transferred to a microwave reactor at 400 W and 60°C for 4 hours. After the reaction was completed, it was cooled to room temperature, filtered and dried to obtain the divinyl hexamethylsilsesquioxane monomer.

[0020] Embodiment 3:

[0021] Synthesis of the same series of products: Under the same conditions, the molar ratio of methyltrimethoxysilane to vinyltrimethoxysilane was changed to 7:1, and the remaining processing steps were the same as those in Example 2 to synthesize monovinylheptamethylsilsesquioxane.

Claims

1. A method for preparing vinyl silsesquioxane (POSS) by microwave synthesis, which is achieved by hydrolysis and condensation reaction, characterized in that Follow these steps: The first method is to hydrolyze and condense vinyltrimethoxysilane (VTS) in a microwave reactor to obtain octavinyl POSS monomer. The second method: methyltrimethoxysilane (MTS) and vinyltrimethoxysilane (VTS) undergo hydrolysis and condensation reaction under the action of a microwave reactor to obtain a divinyl hexamethyl POSS monomer.

2. The preparation method of type 1 according to claim 1, characterized in that: The raw material is only vinyltrimethoxysilane (VTS), the reaction time is 3h, the reaction temperature is 60℃, and the reaction power is 400W.

3. The preparation method of type 2 according to claim 1, characterized in that: The molar ratio of methyltrimethoxysilane (MTS) to vinyltrimethoxysilane (VTS) is 3:1, the reaction time is 4h, the reaction temperature is 60°C, and the reaction power is 400W.