TWI820516B - A kind of liquid crystal composition containing cyclohexene structure and its preparation method and application - Google Patents

Abstract

The invention belongs to the technical field of liquid crystal compounds, and specifically relates to a liquid crystal composition containing a cyclohexene structure and its preparation method and application. The liquid crystal composition containing a cyclohexene structure has a structure represented by general formula (I). The liquid crystal compound of the present invention has a higher clearing point, relatively high optical anisotropy, low rotational viscosity, good thermal stability, chemical stability, optical stability and mechanical properties, and can improve liquid crystal It displays the response speed of the device and has the characteristics of good charge retention rate.

Description

A kind of liquid crystal composition containing cyclohexene structure and its preparation method and application

The invention belongs to the technical field of liquid crystal compounds, and specifically relates to a liquid crystal composition containing a cyclohexene structure and its preparation method and application.

Since the discovery of commercially viable liquid crystal materials 30 years ago. The application of liquid crystal materials in information display materials, organic optoelectronic materials and other fields has great research value and bright application prospects. As a new display material, liquid crystal materials have many advantages, such as extremely low power consumption and low driving voltage. At the same time, compared with other materials, it also has the advantages of small size, light weight, long life, large amount of displayed information, and no electromagnetic radiation. It can adapt to almost all kinds of information display requirements, especially in TFT-LCD (Thin Film Transistor Technology) products. aspect.

In TFT active matrix systems, there are mainly TN (Twisted Nematic, twisted nematic structure) mode, IPS (In-Plane Switching, plane conversion) mode, FFS (Fringe Field Switching, fringe field switching technology) mode and VA ( Vertical Alignment, vertical orientation) mode and other main display modes.

At present, TFT-LCD product technology has gradually matured and successfully solved technical problems such as viewing angle, resolution, color saturation and brightness. Large-sized and small- and medium-sized TFT-LCD displays have gradually occupied the mainstream position of flat panel displays in their respective fields. . But for dynamic screen display applications, For example, mobile phones and TVs require liquid crystal materials to have a fast response speed in order to achieve high-quality display and eliminate image afterimages and smearing. Therefore, liquid crystal materials are required to have a rotational viscosity γ1 as low as possible.

In order to improve the properties of materials and adapt them to new requirements, the synthesis of new structural liquid crystal compounds and the study of structure-property relationships have become an important task in the field of liquid crystals.

The first object of the present invention is to provide a new type of liquid crystal composition containing a liquid crystal compound containing a cyclohexene structure, so as to improve the shortcomings of existing liquid crystal materials and enhance the application value of such liquid crystal compounds.

The liquid crystal compound of the present invention has a structure represented by general formula (I):

In the general formula (I), R ₁ and R ₂ are the same or different, and are each independently selected from -H, -Cl, -F, -CN, -OCN, -OCF ₃ , -CF ₃ , -CHF ₂ , -CH ₂ F, -OCHF ₂ , -SCN, -NCS, -SF ₅ , C ₁ -C ₁₂ alkyl group or C ₁ - ₁₂ alkoxy group, wherein the C ₁ -C ₁₂ alkyl group or C One or more hydrogens in the alkoxy groups of ₁ to ₁₂ may be optionally replaced by fluorine or chlorine, and one or more -CH ₂ - may be optionally replaced by cyclopentyl, cyclopropyl or cyclobutyl ;A1 is selected from a single bond or one of the following groups:

Preferably, in the general formula (I), R ₁ and R ₂ are the same or different, and each is independently selected from -H, a C ₁ -C ₇ alkyl group or a C ₁ -C ₇ alkoxy group, wherein the C One or more -CH ₂ - in the ₁ -C ₇ alkyl group or the C ₁ -C ₇ alkoxy group may be optionally replaced by a cyclopentyl, cyclopropyl or cyclobutyl group.

Further preferably, in the general formula (I), R ₁ is selected from a C ₁ -C ₇ alkyl group or a C ₁ -C ₇ alkoxy group; R ₂ is selected from a C ₁ -C ₇ alkoxy group; wherein One or more -CH ₂ - in the C ₁ -C ₇ alkyl group or C ₁ -C ₇ alkoxy group may be optionally replaced by a cyclopentyl group, a cyclopropyl group or a cyclobutyl group.

Preferably, in general formula (I), said A1 is selected from one of the following groups:

。 Preferably, the liquid crystal compound of the present invention is selected from one or more of the following compounds:

.

The second object of the present invention is to provide a preparation method for the above-mentioned liquid crystal compound, and its synthesis route is as follows:

與丁基鋰製備鋰試劑，鋰試劑與

反應，制得

；2)

與對甲苯磺酸反應脫水，得

；其中，R₁、R₂、A1的定義同上。 Specifically, it includes the following steps: 1)

Prepare lithium reagent with butyllithium, lithium reagent with

react, make

;2)

React with p-toluenesulfonic acid and dehydrate to obtain

; Among them, the definitions of R ₁ , R ₂ and A1 are the same as above.

The method of the present invention will involve conventional post-processing when necessary. The conventional post-processing specifically includes: extraction with methylene chloride, ethyl acetate or toluene, liquid separation, water washing, drying, and evaporation with a vacuum rotary evaporator. The product can be purified by vacuum distillation or recrystallization and/or chromatographic separation.

The liquid crystal compound of the present invention can be obtained stably and efficiently using the above preparation method.

A third object of the present invention is to protect compositions containing said liquid crystal compounds. Among them, the addition amount of the above-mentioned liquid crystal compound is preferably 1 to 60%, more preferably 3 to 50%, and even more preferably 5~25%. Those skilled in the art can predict that the addition of the above-mentioned liquid crystal compounds can further improve the optical anisotropy of existing conventional liquid crystal compositions, and have the technical effect of shortening the response time.

The fourth object of the present invention is to protect the application of the above-mentioned liquid crystal compounds and compositions containing the above-mentioned liquid crystal compounds in the field of liquid crystal display, preferably in liquid crystal display devices. The liquid crystal display device is further preferably a VA or PSVA display. After the above liquid crystal composition is applied to a liquid crystal display device, it has the advantage of shortening the response time.

The invention has the following beneficial effects:

The liquid crystal compound of the present invention has a higher clearing point, relatively high optical anisotropy, low rotational viscosity, good thermal stability, chemical stability, optical stability and mechanical properties, and improves the performance of liquid crystals. It displays the response speed of the device and has the characteristics of good charge retention rate.

The liquid crystal compound of the present invention has a structure represented by general formula (I):

In the general formula (I), R ₁ and R ₂ are the same or different, and are each independently selected from -H, -C1, -F, -CN, -OCN, -OCF ₃ , -CF ₃ , -CHF ₂ , -CH ₂ F, -OCHF ₂ , -SCN, -NCS, -SF ₅ , C ₁ -C ₁₂ alkyl group or C ₁ - ₁₂ alkoxy group, wherein the C ₁ -C ₁₂ alkyl group or C One or more hydrogens in the alkoxy groups of ₁ to ₁₂ may be optionally replaced by fluorine or chlorine, and one or more -CH ₂ - may be optionally replaced by cyclopentyl, cyclopropyl or cyclobutyl ;A1 is selected from a single bond or one of the following groups:

Preferably, in the general formula (I), R ₁ and R ₂ are the same or different, and each is independently selected from -H, a C ₁ -C ₇ alkyl group or a C ₁ -C ₇ alkoxy group, wherein the C One or more -CH ₂ - in the ₁ -C ₇ alkyl group or the C ₁ -C ₇ alkoxy group may be optionally replaced by a cyclopentyl, cyclopropyl or cyclobutyl group.

Further preferably, in the general formula (I), R ₁ is selected from a C ₁ -C ₇ alkyl group or a C ₁ -C ₇ alkoxy group; R ₂ is selected from a C ₁ -C ₇ alkoxy group; wherein One or more -CH ₂ - in the C ₁ -C ₇ alkyl group or C ₁ -C ₇ alkoxy group may be optionally replaced by a cyclopentyl group, a cyclopropyl group or a cyclobutyl group.

Preferably, in general formula (I), said A ₄ 1 is selected from one of the following groups:

。 Preferably, the liquid crystal compound of the present invention is selected from one or more of the following compounds:

.

The present invention provides a preparation method for the above-mentioned liquid crystal compound, and its synthesis route is as follows:

與丁基鋰製備鋰試劑，鋰試劑與

反應，制得

；2)

與對甲苯磺酸反應脫水，得

；其中，R₁、R₂、A1的定義同上。 Specifically, it includes the following steps: 1)

Prepare lithium reagent with butyllithium, lithium reagent with

react, make

;2)

React with p-toluenesulfonic acid and dehydrate to obtain

; Among them, the definitions of R ₁ , R ₂ and A1 are the same as above.

The method of the present invention will involve conventional post-processing when necessary. The conventional post-processing specifically includes: extraction with methylene chloride, ethyl acetate or toluene, liquid separation, water washing, drying, and evaporation with a vacuum rotary evaporator. The product can be purified by vacuum distillation or recrystallization and/or chromatographic separation.

The liquid crystal compound of the present invention can be obtained stably and efficiently using the above preparation method.

The composition of the liquid crystal compound of the present invention. Among them, the addition amount of the above-mentioned liquid crystal compound is preferably 1 to 60%, more preferably 3 to 50%, and further preferably 5 to 25%. Those skilled in the art can It is foreseen that the addition of the above-mentioned liquid crystal compounds can further improve the optical anisotropy of existing conventional liquid crystal compositions and have the technical effect of shortening the response time.

The application of the composition containing the above-mentioned liquid crystal compound of the present invention in the field of liquid crystal display is preferably used in a liquid crystal display device, and the liquid crystal display device is further preferably a VA or PSVA display. After the above liquid crystal composition is applied to a liquid crystal display device, it has the advantage of shortening the response time.

The invention has the following beneficial effects:

The liquid crystal compound of the present invention has a higher clearing point, relatively high optical anisotropy, low rotational viscosity, good thermal stability, chemical stability, optical stability and mechanical properties, and improves the performance of liquid crystals. It displays the response speed of the device and has the characteristics of good charge retention rate.

The following examples are used to illustrate the invention but are not intended to limit the scope of the invention.

Unless otherwise stated, the raw materials can be obtained from open commercial channels (such as those provided by Beijing 800 Million Time and Space).

Example 1

This embodiment relates to a liquid crystal compound whose structural formula is as follows:

Its synthesis route is as follows:

The specific synthesis steps are as follows:

1. Synthesis of BYLC-01

Add 0.2L anhydrous tetrahydrofuran to a 1L four-neck flask, and replace and evacuate 31.6g (0.2mol) of 2,3-difluorophenylethyl ether (BYLC-01-1) with nitrogen three times. Cool down to -70 degrees. Add butyllithium 2.5M 80ml dropwise to control the dropping speed and the temperature at -70~-80℃. After the dropwise addition is completed, continue to keep warm for 1 hour.

Add dropwise a mixed solution of 44.8g propyltetrahydropyrancyclohexanone (BYLC-01-2) and 150L tetrahydrofuran, keeping the reaction temperature at -70~-80°C. After the dropwise addition is completed, take samples for tracking after another 3 hours of incubation. When the remaining raw materials are <0.5%, stop the reaction.

Add 200mL toluene to the reaction solution, distill tetrahydrofuran under normal pressure at 80~90°C, distill out most of the tetrahydrofuran, cool the reaction solution to room temperature (20~30°C), and slowly pour 0.2L hydrochloric acid and 0.5 Hydrolyze in dilute hydrochloric acid solution prepared with L ice water, cool externally with freezing liquid, and control the temperature at 15~25°C. After pouring, stir, let stand, and separate. Extract the aqueous phase twice with 1L*2 toluene, combine the organic layers, and wash the organic layer twice with 1L*2 saturated brine until neutral.

The organic phase was concentrated (at normal pressure) and the temperature was raised to 110°C. The resulting concentrated liquid, with a purity of 88% as the main GC product, was directly used in the next step of dehydration reaction.

Add the concentrated solution, 10g p-toluenesulfonic acid, 1.5g BHT, and 100mL ethylene glycol to a 51L four-neck bottle, raise the temperature to 110°C, reflux the reaction solution, and use a water separator to separate the water. Control the reflux speed, start sampling after 3 hours, and separate out about 50g of water. Stop heating and stir until temperature drops to room temperature.

Add 1L pure water to the reaction solution while stirring, stir, and separate the lower aqueous phase after letting it stand. Add 0.2L pure water to the upper organic phase, stir, let it stand, and separate the liquids. The combined aqueous phases are extracted once with 100 mL of toluene, and the two phases are extracted once. The obtained organic phases were combined and washed three times with 0.2L*3 saturated brine, and the aqueous phase was discarded. Add 50g of anhydrous sodium sulfate to the obtained organic phase, dry for 2 hours, filter, and rinse the filter cake with 100 mL of toluene.

Pour the filtrate liquid into a silica gel column made of 100g silica gel, and start to pass through the column at normal pressure. After passing through the column, the light yellow liquid passing through the column will be concentrated under reduced pressure.

The obtained liquid was passed through the column, the temperature was raised to 60.0~70.0℃, the vacuum degree was -0.08~-0.09MPa, concentrated, and recrystallized twice with absolute ethanol to obtain 54.6g of white solid, BYLC-01. The purity is 99.9% and the yield is 75%.

The obtained white solid BYLC-01 was analyzed by GC-MS, and the m/z of the product was 3364.2 (M+).

Example 2

This embodiment relates to a liquid crystal compound whose structural formula is as follows:

Compared with Example 1, the synthetic route only involves a simple replacement of raw materials; the obtained white solid BYLC-02 was analyzed by GC-MS, and the m/z of the product was 366.2 (M+).

Example 3

採用GC-MS對所得白色固體BYLC-03進行分析，產物的m/z為364.2(M+)。 This embodiment relates to a liquid crystal compound whose structural formula is as follows:

The obtained white solid BYLC-03 was analyzed by GC-MS, and the m/z of the product was 364.2 (M+).

Example 4

其合成路線與實施例3相比僅進行原料的簡單替換；採用GC-MS對所得白色固體BYLC-04進行分析，產物的m/z為366.2(M+)。 This embodiment relates to a liquid crystal compound whose structural formula is as follows:

Compared with Example 3, the synthetic route only involves a simple replacement of raw materials; the obtained white solid BYLC-04 was analyzed by GC-MS, and the m/z of the product was 366.2 (M+).

Example 5

其合成路線與實施例3相比僅進行原料的簡單替換；採用GC-MS對所得白色固體BYLC-05進行分析，產物的m/z為392.2(M+)。 This embodiment relates to a liquid crystal compound whose structural formula is as follows:

Compared with Example 3, the synthetic route only involves a simple replacement of raw materials; the obtained white solid BYLC-05 was analyzed by GC-MS, and the m/z of the product was 392.2 (M+).

Example 6

採用GC-MS對所得白色固體BYLC-06進行分析，產物的m/z為418.2(M+)。 This embodiment relates to a liquid crystal compound whose structural formula is as follows:

The obtained white solid BYLC-06 was analyzed by GC-MS, and the m/z of the product was 418.2 (M+).

Experimental example

This experimental example involves the measurement of relevant properties of the compounds described in Examples 1 to 6.

According to the conventional detection methods in this field, for example, γ1 is detected using a viscometer, Δn is detected using an Abbe refractometer, and Cp is detected using a differential calorimeter scanner.

Various performance parameters of the liquid crystal compound are obtained through linear fitting. The specific meanings of each performance parameter are as follows:

△n represents optical anisotropy (25℃); γ1 represents rotational viscosity (mPa.s, 25℃); Cp represents clearing point.

The performance parameter data of the liquid crystal compounds prepared in Examples 1 to 6 and the liquid crystal compounds of Comparative Examples 1 to 3 were compared and organized. The test results are as shown in Table 1:

It can be clearly seen from the test results in Table 1 that compared with traditional compounds with similar chemical structures, the liquid crystal compound provided by the present invention has lower rotational viscosity γ1, larger optical anisotropy Δn, and higher clarity. The highlight Cp can improve the response time and increase the working temperature of the liquid crystal composition.

Although the present invention has been described in detail above with general descriptions, specific embodiments and tests, it is obvious to those skilled in the art that some modifications or improvements can be made on the basis of the present invention. . Therefore, these modifications or improvements made without departing from the spirit of the present invention all fall within the scope of protection claimed by the present invention.

Claims (9)

A liquid crystal composition containing a cyclohexene structure, characterized in that it has a liquid crystal compound having a structure represented by general formula (I):

In the general formula (I), R ₁ and R ₂ are the same or different, and are each independently selected from -H, -Cl, -F, -CN, -OCN, -OCF ₃ , -CF ₃ , -CHF ₂ , -CH ₂ F, -OCHF ₂ , -SCN, -NCS, -SF ₅ , C ₁ -C ₁₂ alkyl group or C ₁ - ₁₂ alkoxy group, wherein the C ₁ -C ₁₂ alkyl group or C One or more hydrogens in the alkoxy groups of ₁ to ₁₂ may be optionally replaced by fluorine or chlorine, and one or more -CH ₂ - may be optionally replaced by cyclopentyl, cyclopropyl or cyclobutyl ;A1 is selected from one of the following groups:

The liquid crystal composition containing a cyclohexene structure as described in claim 1, wherein R ₁ and R ₂ are the same or different, and each is independently selected from -H, a C ₁ -C ₇ alkyl group or a C ₁ -C ₇ an alkoxy group; wherein one or more -CH ₂ - in the C ₁ -C ₇ alkyl group or C ₁ -C ₇ alkoxy group may optionally be replaced by a cyclopentyl group, a cyclopropyl group or a cyclopropyl group. Butyl substitution. The liquid crystal composition containing a cyclohexene structure as described in claim 2, wherein R ₁ is selected from a C ₁ -C ₇ alkyl group or a C ₁ -C ₇ alkoxy group; R ₂ is selected from a C ₁ -C ₇ alkoxy group; wherein one or more -CH ₂ - in the C ₁ -C ₇ alkyl group or C ₁ -C ₇ alkoxy group may optionally be replaced by cyclopentyl, cyclopropyl or cyclobutyl substitution. The liquid crystal composition containing a cyclohexene structure as claimed in claim 1, wherein the liquid crystal compound represented by the general formula (I) is selected from one or more of the following structures:

. A method for preparing the liquid crystal compound of the liquid crystal composition described in any one of claims 1 to 4, wherein the synthesis route is as follows:

Specifically, it includes the following steps: 1)

Prepare lithium reagent with butyllithium, lithium reagent with

react, make

;2)

React with p-toluenesulfonic acid and dehydrate to obtain

; Among them, the designations of R ₁ , R ₂ and A1 are the same as those described in any one of claims 1-3. A liquid crystal composition, which includes the liquid crystal compound described in any one of claims 1 to 4. The liquid crystal composition according to claim 6, wherein the mass percentage of the liquid crystal compound in the liquid crystal composition is 1 to 60%. An application in the field of liquid crystal display, which contains the liquid crystal compound described in any one of claims 1-4 or the liquid crystal composition described in claim 6 or 7. The application as claimed in claim 8, wherein the liquid crystal display field is a liquid crystal display device, and the liquid crystal display device is a VA or PSVA display.