Unlock instant, AI-driven research and patent intelligence for your innovation.

Method for purifying liquid crystal intermediate 3,4,5-trifluorophenol

A technology of trifluorophenol and purification method, which is applied in chemical instruments and methods, organic chemistry, preparation of organic compounds, etc.

Inactive Publication Date: 2018-02-02
常州润联化工有限公司
View PDF0 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] So far, there is no domestic and foreign literature report about separating near-boiling impurities from crude product 3,4,5-trifluorophenol

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] 2.5kg 3,4,5-trifluorophenol crude product, wherein the content of toluene is 2%, the content of near-boiling impurities 3,5-difluorophenol is 0.05%, the content of 3,4-difluorophenol is 0.03%, and the content of 2,4-difluorophenol Phenol content 0.025%, 2,3,5-trifluorophenol content 0.07%, 2,3,4-trifluorophenol content 0.042%, 2,4,6-trifluorophenol content 0.01%, product 3, 4, 5 - Trifluorophenol content is 97.8%.

[0032] Put this crude material into a 5L rectifying still, and add 1.5kg of p-tert-butyltoluene. After reducing the pressure to 100 mmHg and refluxing for 1 hr, the fraction of p-tert-butyltoluene was collected from the top of the tower with a reflux ratio of 1:1. After collection, GC analysis of tower still samples, the toluene content was not detected, 3,5-difluorophenol contained 50ppm, 3,4-difluorophenol 62ppm, 2,4-difluorophenol 2ppm, 2,3,5- Trifluorophenol 3ppm, 2,3,4-trifluorophenol 2ppm, this material is steamed out from tower top, the high-purity ...

Embodiment 2

[0034] 300kg 3,4,5-trifluorophenol crude product, wherein the content of toluene is 3%, the content of near-boiling impurities 3,5-difluorophenol is 0.06%, the content of 3,4-difluorophenol is 0.02%, and the content of 2,4-difluorophenol Content 0.03%, 2,3,5-trifluorophenol content 0.06%, 2,3,4-trifluorophenol content 0.03%, 2,4,6-trifluorophenol not detected, product 3,4,5- The content of trifluorophenol is 96.8%. Put this crude material into a 500L rectification column kettle, and add 1,2,4-trimethylbenzene 180kg. After reducing the pressure to 120 mmHg and refluxed for 2 hours, the 1,2,4-trimethylbenzene fraction was distilled from the top of the tower with a reflux ratio of 1.5:1.0. After evaporating, GC analysis of tower kettle sample, no toluene was detected, 3,5-difluorophenol contained 60ppm, 3,4-difluorophenol contained 55ppm, 2,4-difluorophenol contained 3ppm, 2,3,5- Trifluorophenol contains 2ppm, and 2,3,4-trifluorophenol contains 2ppm. This material is steamed fr...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
melting pointaaaaaaaaaa
Login to View More

Abstract

The invention relates to a method for purifying a liquid crystal intermediate 3,4,5-trifluorophenol. The method comprises the following steps: carrying out azeotropic rectification on an inert solventand crude 3,4,5-trifluorophenol containing various impurities having similar boiling points in a rectifying tower, discharging the inert solvent entraining the various impurities having similar boiling points, being low boiling point substances, from the top of the tower, and distilling off highly-pure 3,4,5-trifluorophenol with the purity reaching 99.95% or above. The method has the advantagesof simplicity in operation, simple device, low production cost and high yield, and is suitable for large-scale industrial production.

Description

technical field [0001] The present invention relates to a kind of purification method of liquid crystal intermediate 3,4,5-trifluorophenol, specifically a method for separating liquid crystal intermediate 3,4,5-trifluorophenol near boiling point by using inert solvent azeotropic distillation impurity method. Background technique [0002] 3,4,5-Trifluorophenol is an important liquid crystal intermediate, mainly used in the production of fourth-generation TFT color liquid crystal materials. [0003] When synthesizing 3,4,5-trifluorophenol, a variety of impurities will be produced, some of which will seriously affect the quality of liquid crystal materials if not removed, these impurities include 3,5-difluorophenol, 3,4-difluorophenol, Fluorophenol, 2,4-difluorophenol, 2,3,5-trifluorophenol, 2,3,4-trifluorophenol, 2,4,6-trifluorophenol, etc. The boiling points of these impurities are very close to those of the product 3,4,5-trifluorophenol, some only differ by 1-2°C, and thei...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): C07C37/78C07C39/27
CPCC07C37/78C07C37/685C07C39/27
Inventor 言兆福
Owner 常州润联化工有限公司