A kind of purification method of cyclohexene liquid crystal intermediate

A purification method and intermediate technology, which is applied in the field of purification of cyclohexene liquid crystal intermediates, can solve the problems of multi-noble metal catalyst usage, excessive reaction time, affecting product yield and purity, etc., so that the catalyst is not easy to be poisoned and applied mechanically repeatedly , Fewer alkene impurity residues, improved purification effect

Active Publication Date: 2022-02-18
江阴市华亚化工有限公司
View PDF8 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] However, in the current preparation process of liquid crystal monomers containing cyclohexane groups, the main problem is: when synthesizing cyclohexenyl intermediates through Grignard reactions, the purification of crude products is not enough, resulting in hydrogenation and reduction by metal catalysts in the next step. For cyclohexene, the noble metal catalyst is poisoned due to the impurity of the hydrogenation substrate, which makes the hydrogenation reaction incomplete, the reaction is too long, and the cyclohexenyl intermediate remains too much; in addition, some cyclohexane liquid crystals containing fluorine benzene The intermediate will also produce fluorine impurities due to the long hydrogenation reaction time, which will affect the product yield and purity; at the same time, the substrate of the hydrogenation reaction is impure, which will cause excessive consumption of precious metal catalyst usage, and the precious metal catalyst will be used because of It is easy to be poisoned, the activity is greatly reduced, and basically cannot be applied again, which increases the cost of the process
[0007] At present, when processing and purifying liquid crystal intermediates containing cyclohexene groups in the liquid crystal material industry, the crude cyclohexene intermediates are mainly dissolved and then filtered by column chromatography through silica gel polar adsorbents. The dissolved cyclohexene When the crude olefin intermediate flows through the chromatographic column, the time for the adsorption and removal of impurities by the chromatographic column is not enough, and various impurities cannot be effectively adsorbed and removed, thereby affecting the subsequent hydrogenation reaction; at the same time, only a single method for removing polar impurities is used Silica gel-based adsorbents cannot effectively remove non-polar impurities with low polarity. Substrates after these conventional purification treatments generally suffer from slow hydrogenation, incomplete reaction, many residual alkene impurities, and easy catalysts in subsequent hydrogenation reactions. Problems such as poisoning cannot be applied mechanically, which increase the preparation cost of this type of liquid crystal monomer

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

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • A kind of purification method of cyclohexene liquid crystal intermediate
  • A kind of purification method of cyclohexene liquid crystal intermediate
  • A kind of purification method of cyclohexene liquid crystal intermediate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Add 100g of propylcyclohexylcyclohexenylethane (GC: 99.5%) to the 1L three-necked flask to purify the crude product, add 200ml of non-polar solvent n-hexane, add 25g of active silica gel, add 25g of active powder activated carbon, start stirring, and rotate 50hz, control the temperature of the material system at 60°C, stir and adsorb for 1 hour, and cool down to 25°C; use a filter funnel to filter and separate the solid adsorbent and liquid product, and the liquid product is rotary evaporated to concentrate the solvent. After concentration, add 1 times absolute ethanol to the product and cool down Refrigerate and recrystallize at -30°C for 2 hours, filter out the solid product, and test the product (GC: 99.9%).

[0033] The obtained intermediate after stirring, adsorbing and purifying the mixed adsorbent of silica gel and activated carbon, added 2 times the volume of absolute ethanol, 5% palladium carbon catalyst with 5% weight ratio of the substrate, 0.1MPa hydrogen pre...

Embodiment 2

[0039]Add 100g of propylcyclohexylcyclohexenyl-3,4,5-trifluorobenzene (GC: 99.7%) to a 1L three-neck flask to purify the crude product, add 300ml of non-polar solvent n-hexane, 100ml of toluene, and 25g of active silica gel , add 25g of active powder activated carbon, start stirring, rotate at 50hz, control the temperature of the material system at 60°C, stir and adsorb for 1 hour, then cool down to 25°C; use a filter funnel to filter and separate the solid adsorbent and liquid product, and the liquid product is rotary evaporated to concentrate the solvent and concentrate Finally, 5 times of absolute ethanol was added to the product, cooled to -20°C for 2 hours of freezing and recrystallization, and the solid product was filtered out, and the product was tested (GC: 99.9%).

[0040] After stirring and adsorbing the purified intermediate of silica gel and active carbon mixed adsorbent, add 2 times of volume of absolute ethanol, 3 times of volume of toluene, 5% palladium carbon c...

Embodiment 3

[0046] Add 100g of propylcyclohexylcyclohexenyl-4-trifluoromethoxybenzene (GC: 99.8%) to a 1L three-neck flask to purify the crude product, add 400ml of non-polar solvent n-hexane, add 25g of active silica gel, and add active powder Activated carbon 25g, start stirring, speed 50hz, control material system temperature 60°C, stir and adsorb for 1 hour, cool down to 25°C; use filter funnel to filter and separate solid adsorbent and liquid product, liquid product is rotary evaporated to concentrate solvent, after concentration, add 4 times absolute ethanol, cooled to -20°C, frozen and recrystallized for 2 hours, the solid product was filtered out, and the product was tested (GC: 99.9%).

[0047] After stirring and adsorbing the purified intermediate of silica gel and active carbon mixed adsorbent, add 3 times of volume dehydrated alcohol, 2 times of volume of toluene, 5% palladium carbon catalyst of substrate 5% by weight, 0.1MPa hydrogen pressure, and add Hydrogen reaction for 8 ...

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

No PUM Login to view more

Abstract

The invention relates to a method for purifying a cyclohexene-based liquid crystal intermediate, which is suitable for the liquid crystal intermediate containing a cyclohexene group that needs to be catalytically hydrogenated and reduced by precious metals, specifically the liquid crystal intermediate containing a cyclohexene group Put the crude product to be purified into a kettle-type container with stirring, heating, and heat preservation functions, add a non-polar solvent to dissolve, put in a mixture of polar adsorbent and non-polar adsorbent for adsorption, and absorb at the set temperature and speed of stirring and adsorption Purification is carried out under the time; after stirring adsorption purification, the adsorbent and the product solution are separated by filtration, the product solution is concentrated to remove the solvent, and then recrystallized and purified to obtain the final product. The purification method of the cyclohexene liquid crystal intermediate of the present invention adopts a temperature-controllable and time-controlled kettle-type container, and adopts a polar adsorbent and a non-polar adsorbent at the same time, and the liquid crystal intermediate obtained by it is in the catalytic hydrogenation reaction It can be hydrogenated faster, has less residue of olefinic impurities, and is not easy to catalyze poisoning.

Description

technical field [0001] The invention belongs to the technical field of purification of liquid crystal compounds, and in particular relates to a method for purifying a cyclohexene liquid crystal intermediate. Background technique [0002] Liquid crystal displays using liquid crystal compositions are widely used in displays such as instruments, computers, and televisions, and liquid crystal compositions, as one of the important optoelectronic materials of liquid crystal displays, play an important role in improving the performance of liquid crystal displays. At present, a large number of liquid crystal compounds with different molecular structures have appeared on the market, from biphenylnitriles, esters, oxygen-containing heterocycles, and pyrimidine ring liquid crystal compounds to cyclohexylbenzenes, phenylacetylenes, and ethyl bridges. Class, terminal alkenyl liquid crystals and various fluorine-containing aromatic ring liquid crystal compounds, etc., continuously meet th...

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 Patents(China)
IPC IPC(8): C07C7/12C07C17/38C07C17/389C07C41/34C07C41/36C07C7/00C07C13/28C07C23/18C07C43/225C07B63/00
CPCC07C7/12C07C7/005C07C17/38C07C17/389C07C41/36C07C41/34C07B63/00C07C2601/14C07C2601/16
Inventor 谭建新李玉柱高鑫滕超周小勇
Owner 江阴市华亚化工有限公司
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Try Eureka
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap