Method for removing impurities from organic siloxane mixed ring body

Abstract

The invention discloses a method for removing impurities from methyl siloxane mixed ring DMC, and the method comprises: mixing hydrogen peroxide, activated carbon fiber and the DMC under the heating condition to remove hydroxyl compounds, unsaturated group compounds, metal ions and other impurities in the DMC, then filtering by an ultrafiltration membrane, standing, layering, and removing water from the upper-layer DMC by bubbling through nitrogen to obtain refined DMC. In the process, the hydrogen peroxide can oxidize the impurities such as the hydroxyl, unsaturated group compounds and the like in the DMC, and the active carbon fiber is modified, so that oxygen-containing groups are increased, and the selective adsorption effect on the metal ions is enhanced. The method has the advantagesthat the process flow is simple, hydrogen peroxide decomposition products are pollution-free, the activated carbon fiber and the ultrafiltration membrane can be repeatedly used, the content of the impurities can be reduced by more than 70%, and the quality of the DMC is improved.

Description

technical field [0001] The invention relates to a process for removing impurities of organic silicon chemical raw material DMC. Background technique [0002] 1. DMC is an important organic silicon intermediate product, which is widely used in the synthesis of silicone oil and silicone rubber. It is mainly composed of hexamethylcyclotrisiloxane, octamethylcyclotetrasiloxane, decamethylcyclopentasiloxane Oxygen composition. DMC is mainly prepared by halosilane hydrolysis, cracking and then rectification. Due to the production process and other reasons, DMC products often contain impurities such as water, hydroxyl compounds, and unsaturated group compounds. In addition, they also contain trace amounts of iron ions, aluminum ions, Metal ions such as manganese ions and titanium ions, and heavy metal ions such as lead impurities. The presence of these impurities will affect the activity of the catalyst during the production process and affect the performance of the final silicon...

AI Technical Summary

Problems solved by technology

[0003] 2. Various methods can be used to reduce DMC impurities. Patent CN103450249A introduces a DMC impurity removal method, which mixes activated carbon, flocculant, and industrial alkali and presses it into a filter cake. DMC is removed by filtration. Although the miscellaneous method is simple and easy, and the energy consumption is lower than that of rectification, it can only decolorize DMC and remove particles, but cannot further remove water, and has poor adsorption to ions and is easy to introduce carbon black and flocculants. Other impurities

CN103374027A has introduced a kind of washing method to remove the impurity of DMC, and this method is by adding certain water, precipitant, neutralizing agent in DMC, leaves standstill after stirring, and obtains refined DMC after exhausting water, although this method reaction time Short, low power consumption, but easy to introduce water and other ionic impurities

CN101376662B adopts the resin adsorption method to refine the ring body. Although the resin can be reused and the cost is low in this method, the adsorption effect is not very satisfactory, and the impurity content after adsorption is as high as 450PPM or more

CN105481891A introduces a rectification method for organosiloxane mixed rings, which uses four times of molecular distillation to treat different components separately, but this method consumes a lot of energy and some ion impurities are difficult to remove

CN1271017C has introduced a kind of method of extracting moisture impurity in DMC, and it extracts moisture by the method for heating and nitrogen bubbling, and this method is high to the extracting efficiency of water, but has no effect to ion impurity

CN105061490A Combination of peroxide oxidation and molecular sieve drying and filtration to remove impurities under alkaline conditions, the advantage is that impurities such as hydroxyl and unsaturated group compounds are reduced through peroxide oxidation, and the water in the peroxide solution dissolves Part of the ionic impurities were removed, and finally the moisture in the raw material was controlled by molecular sieves. However, before molecular sieve filtration, DMC had a large water content and the contact time between DMC and molecular sieves was short during filtration. Although the moisture content was reduced, the metal ion content could not be effectively controlled. In addition, Peroxide decomposes slowly at room temperature, and the free oxygen content in the mixture is low, which affects the oxidation effect

Images