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Method used for purifying octamethylcyclotetrasiloxane

A technology of octamethylcyclotetrasiloxane and heptane, which is applied in the field of purifying octamethylcyclotetrasiloxane, can solve the problems that optical fiber preforms cannot be directly produced and the purity of D4 is not high, so as to improve the purity and good remove selective effects

Inactive Publication Date: 2018-12-04
合盛硅业(泸州)有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of the present invention is to provide a method for purifying octamethylcyclotetrasiloxane to solve the problem that the existing D4 has a low purity and cannot be directly used in the production of optical fiber preforms

Method used

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  • Method used for purifying octamethylcyclotetrasiloxane
  • Method used for purifying octamethylcyclotetrasiloxane
  • Method used for purifying octamethylcyclotetrasiloxane

Examples

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Embodiment 1

[0027] A method for purifying octamethylcyclotetrasiloxane, comprising the following steps:

[0028] (1) The dimethyldichlorosilane hydrolyzate cracks the crude ring through the de-lowering tower to remove D3 and low-boiling impurities with a boiling point below 134°C; then pass through the de-higher tower to remove D5 and the boiling point above 210°C The high-boiling impurity is obtained to obtain the first product D4.

[0029] (2) Add a heptane solution with a mass fraction of 20% to the primary product D4 as a crystallization solvent. The volume ratio of the heptane solution to the primary product D4 is 1:3. 60% of needle-like crystals can appear in 5 minutes at -10°C, smash the crystals in the solution at -10°C, and quickly obtain pure crystals through vacuum filtration;

[0030] (3) Transfer the crystals to an environment at 25°C to melt them. After the melted liquid is subjected to vacuum distillation through a vacuum rectification tower, the residual heptane is remove...

Embodiment 2

[0034] A method for purifying octamethylcyclotetrasiloxane, comprising the following steps:

[0035] (1) The dimethyldichlorosilane hydrolyzate cracks the crude ring through the de-lowering tower to remove D3, D5 and low-boiling impurities with a boiling point below 134°C; then pass through the de-higher tower to remove D5 and the boiling point at 210 The high-boiling point impurities above ℃ are obtained to obtain the first product D4.

[0036] (2) Pass the first product D4 through a 13X molecular sieve refining, adsorption and filtration system to remove most of the metal impurities. The metal impurity content before and after the 13X molecular sieve treatment is as shown in Table 2;

[0037] Metal impurity content control table of first product D4 in the embodiment 2 of table 2 before and after 13X molecular sieve treatment

[0038]

[0039] After the 13X molecular sieve treatment, although new impurities such as aluminum, calcium, phosphorus and lead will be brought in...

Embodiment 3

[0046] A method for purifying octamethylcyclotetrasiloxane, comprising the following steps:

[0047] (1) The dimethyldichlorosilane hydrolyzate cracks the crude ring through the de-lowering tower to remove D3, D5 and low-boiling impurities with a boiling point below 134°C; then pass through the de-higher tower to remove D5 and the boiling point at 210 The high-boiling point impurities above ℃ are obtained to obtain the first product D4.

[0048] (2) Pass the first product D4 through a 13X molecular sieve refining, adsorption and filtration system to remove most of the metal impurities. The metal impurity content before and after the 13X molecular sieve treatment is as shown in Table 4;

[0049] Metal impurity content comparison table of first product D4 in the embodiment 3 of table 4 before and after 13X molecular sieve treatment

[0050]

[0051] After the 13X molecular sieve treatment, although new impurities such as aluminum, calcium, phosphorus and lead will be brought...

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Abstract

The invention discloses a method used for purifying octamethylcyclotetrasiloxane (D4), and belongs to the technical field of chemical engineering. According to the method, 13X molecular sieve is adopted to remove most metal impurities in primary product D4; crystallization method is adopted to remove pentamethyl ethyl cyclotrisiloxane, heptamethyl ethyl cyclotetrasiloxane, and nonamethyl ethyl cyclopentasiloxane generated by co-hydrolysis of trace impurity ethyldichlorosilane with dimethyldichlorosilance in D4, impurities before D3 (hexamethyl cyclotrisiloxane), impurities between D4 (octamethylcyclotetrasiloxane) and D5 (decamethylcyclopentasiloxane) such as 2-ethyl-4, 4, 6, 6, 8, 8-hexamethyl cyclotetrasiloxane organic impurities and low boiling point impurities, increase D4 purity effectively. The purity of D4 after purification is 99.98% or higher, and the D4 can be directly used in optical fiber prefabricated rod production.

Description

technical field [0001] The invention relates to the technical field of chemical industry, in particular to a method for purifying octamethylcyclotetrasiloxane. Background technique [0002] Silicone material is a new type of chemical material developed in recent decades. It is a new type of material with excellent performance, unique function and wide application. The main products include silicone oil, silicone rubber, silicone resin, silane, etc., with its excellent performance It is widely used in aerospace, electronic appliances, automobiles, shipbuilding, light industry, machinery, agriculture, daily chemical and medical and health industries. [0003] Using silicon-containing substances through high-temperature pyrolysis to produce SiO 2 The fine powder is deposited on the mandrel to form loose SiO 2 The embryo body is sintered to form a quartz glass prefabricated rod, which is used to produce optical fiber products. Theoretically speaking, any silicon-containing co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07F7/21
CPCC07F7/21
Inventor 陈建刚刘凯张楠母清林张寅旭秦威
Owner 合盛硅业(泸州)有限公司