Method for preparing long-chain fluoroalkylsiloxane

Abstract

The invention discloses a method for preparing long-chain fluoroalkylsiloxane. According to the method, long-chain fluoroalkylethylene and alkoxy silane are used as raw materials to prepare the long-chain fluoroalkylsiloxane through hydrosilylation. The method is characterized in that a hexafluoroisopropanol solution of chloroplatinic acid is used as a catalyst and the dosage of a platinum catalyst is 10<-5> to 10 <-4> of the molar amount of the alkoxy silane. The method comprises the following steps: under the protection of nitrogen, adding hexafluoroisopropanol into chloroplatinic acid hexahydrate to completely dissolve chloroplatinic acid so as to prepare a chloroplatinic acid / hexafluoroisopropanol solution with a concentration of 1-10 mM; sequentially adding alkoxy silane, long-chain fluoroalkylethylene and the prepared chloroplatinic acid / hexafluoroisopropanol solution into a reactor, and conducting reacting at 40-80 DEG C for 30-60 minutes; and carrying out reduced-pressure distillation on reaction liquid to obtain the target product, namely long-chain fluoroalkylsiloxane. The method is simple in process, mild in reaction conditions and high in product yield and purity.

Description

technical field [0001] The invention relates to a preparation method of long-chain fluoroalkylsiloxane, belonging to the field of fluorosilicon chemistry. Background technique [0002] Fluoroalkyl siloxane has important applications in special coating materials due to its super hydrophobic and oleophobic properties, durability and chemical stability. Long-chain (generally referring to more than 5 carbons) fluoroalkylsiloxanes have high fluorine content and flexible structure, which make them more excellent in superhydrophobicity and self-cleaning than short-chain fluoroalkylsiloxanes. , self-repair and other unique properties, it has extremely high application value and commercial value in high-end equipment and devices. [0003] The preparation of siloxane by noble metal-catalyzed hydrosilylation reaction is one of the most important means of organosilicon functionalization, especially in the industrial production of fluorine-containing alkyl siloxane and its derivatives. ...

AI Technical Summary

Problems solved by technology

However, the Speier catalyst still has the disadvantages of a large amount of catalyst, low selectivity to the target product, and no catalytic activity for some reactions.

Especially for the hydrosilylation reaction of fluoroalkylsiloxanes, especially long-chain fluoroalkylsiloxanes, the reactivity of long-chain fluorine-containing olefins is worse than that of small molecule olefins. In addition, because fluorocarbons and catalysts , Solvent miscibility is poor, so that hydrosilylation requires longer reaction time, higher reaction temperature and reaction pressure, which will increase the formation of silane self-coupling by-products on the one hand, and on the other hand, fluorine-containing olefins are prone to occur at high temperatures Isomerization, thereby reducing the yield and purity of the main product (Y. Furukawa, Journal of Polymer Science Part A: Polymer Chemistry)

[0004] Patent document CN 104497033 A adopts the method of polyvinyl siloxane immobilized chloroplatinic acid catalyst to improve catalyst activity, but the preparation process of immobilized catalyst in this method is complicated, which is not conducive to industrial application

[0005] The patent document CN103936782A adopts the addition of cocatalysts such as pyruvic acid to the chloroplatinic acid / isopropanol catalyst system to improve the yield of hydrosilylation reaction products, but this method is limited to the preparation of hydrocarbon long-chain alkylsiloxanes. Long-chain fluorocarbon-based siloxanes have little catalytic effect