JP2516395B2 - 1,1-dihalogenocyclohexane derivative - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel 4-substituted-1,1-dihalogenocyclohexane derivative and a liquid crystal composition containing the compound as an active ingredient.

(Prior Art and Its Problems) Display elements using liquid crystals are widely used in watches, calculators, and the like. These liquid crystal display elements utilize the optical anisotropy and induced anisotropy of liquid crystal substances. The liquid crystal phase includes a nematic liquid crystal phase, a smectic liquid crystal phase, and a cholesteric liquid crystal phase. Among them, the nematic liquid crystal phase is most widely put into practical use, and smectic liquid crystal applications are being actively developed.

Corresponding to the electro-optic effect applied to liquid crystal displays, they are TN (twisted nematic) type, DS (dynamic scattering).
Type, guest-host type, DAP, etc. display devices, and it is desirable that the liquid crystal substance used for each display a liquid crystal phase in the widest temperature range in nature.

Many liquid crystal compounds have already been known, but at present, there is no single liquid crystal substance that satisfies such conditions, and several liquid crystal substances or non-liquid crystal substances are mixed for practical use. . These substances are required to be stable against moisture, light, heat, air and the like.

A mixture of such liquid crystal substances, that is, a liquid crystal composition is desired to be power-saving, have a wide viewing angle, have a fast response speed, and be resistant to deterioration. Therefore, a threshold voltage (Vth) is required.
Is desired to be low, the optical anisotropy value (Δn) is small, the viscosity is low, and chemically stable.

An object of the present invention is to provide a novel 4-substituted-1,1-dihalogenocyclohexane derivative, and a novel compound useful as a liquid crystal compound. Another object is to provide a liquid crystal composition containing the 4-substituted-1,1-dihalogenocyclohexane derivative.

(Means for Solving Problems) The present invention (second invention) is represented by the general formula (In the above formula, n represents 1 or 2, X represents F or Cl, and R represents a linear or branched alkyl group having 1 to 15 carbon atoms) 4-substituted-1,1-di A halogenocyclohexane derivative and a liquid crystal composition containing the compound as an active ingredient.

The liquid crystal composition of the present invention is characterized by containing at least one component of the compound of the present invention represented by the above formula.
Examples of the component other than the compound of the present invention that can be used as a component of the liquid crystal composition of the present invention include ester compounds, Schiff base compounds, biphenyl compounds, phenylcyclohexane compounds, and heterocyclic compounds.

Specific examples of these compounds include ester-based liquid crystal compounds such as trans-4-alkylcyclohexanecarboxylic acid-4-alkylphenyl ester, trans-4-alkylcyclohexanecarboxylic acid-4-alkoxyphenyl ester, and 4-alkoxybenzoate. Acid-4-
Alkylphenyl ester, 4-alkoxybenzoic acid-
Examples of Schiff base liquid crystal compounds such as 4-cyanophenyl ester and 4- (trans-4-alkylcyclohexyl) benzoic acid-4-cyanophenyl ester include 4-alkoxybenzylidene-4-alkanoyloxyaniline and 4-alkoxybenzylidene- Biphenyl-based liquid crystal compounds such as 4-alkylaniline and 4-alkoxybenzylidene-4-cyanoaniline include 4'-alkyl-4-cyanobiphenyl, 4'-alkoxy-4-cyanobiphenyl, 4'-alkoxy-4-. Examples of the phenylcyclohexane-based compound such as alkylbiphenyl include trans-4-alkyl- (4-cyanophenyl) cyclohexane, trans-4-alkyl- (4-alkoxyphenyl) cyclohexane and the like, and examples of the heterocyclic liquid crystal compound include 5- Archi 2- (4-cyanophenyl) -1,
Examples thereof include 3-dioxane, 5-alkyl-2- (4-cyanophenyl) pyrimidine and 5-cyano-2- (4-alkylphenyl) pyrimidine.

An example of the method for producing the compound of the present invention is shown by the following reaction formula.

(In the above formula, n and R are the same as above) That is, 4-substituted cyclohexanone was reacted with sulfuryl chloride in toluene to produce 1,1-dichloro-4-substituted cyclohexane. This 1,1-dichloro-4-substituted cyclohexane was prepared by AJ Bloodworth et al. (Tetrahedrun Lett.
ers, Vol. 28, No. 44, pp 5347-5350, 1987) to produce 1,1-difluoro-4-substituted cyclohexane by reacting with silver tetrafluoroborate in methylene chloride. Those which can be produced in this manner include 1,1-dichloro-4- (trans-4-alkylcyclohexyl) cyclohexane 1,1-dichloro-4- [trans-4- (trans-4
-Alkylcyclohexyl) cyclohexyl] cyclohexane 1,1-difluoro-4- (trans-4-alkylcyclohexyl) cyclohexane 1,1-difluoro-4- [trans-4- (trans-
4-alkylcyclohexyl) cyclohexyl] cyclohexane can be produced. (Here, alkyl is a straight-chain or branched alkyl group having 1 to 15 carbon atoms.) [Operation and effect of the invention] The compound of the present invention, which has two rings at room temperature, does not show a liquid crystal phase, It has good compatibility with many liquid crystal compounds such as ester type, Schiff base type, biphenyl type, phenylcyclohexane type, and heterocyclic type, and the addition of a small amount of the compound of the present invention to the liquid crystal composition reduces the viscosity. Response speed becomes faster. Further, although the dielectric anisotropy (Δε) is small, the threshold voltage (Vth) is low, and this low voltage driving is an important factor for power consumption. Further, the optical anisotropy value (Δn) is small and the viewing angle is wide.

With this effect, the liquid crystal composition is power-saving and is suitable for a liquid crystal display device having a wide viewing angle.

 The present invention will be described in more detail below with reference to examples.

Example 1 Preparation of 1,1-dichloro-4- (trans-4-pentylcyclohexyl) cyclohexane (when R = C5H11-, n = 1, X = Cl in (Formula I)) 4- (trans-4- 24 g of pentylcyclohexyl) cyclohexane was dissolved in 300 ml of dry toluene. The reaction solution was ice-cooled, and 26 g of excess sulfuryl chloride was gradually added while stirring well. 80 after reacting at room temperature for 3 hours
The reaction was carried out at 0 ° C for 5 hours. After cooling, the reaction solution was poured into ice water and the toluene layer was separated with a separating funnel. Toluene layer
After washing 3 times with 2N NaOH, it was washed with water until neutral.
After drying over anhydrous sodium sulfate, toluene was distilled off under reduced pressure. A column of activated alumina was passed through using dried toluene as a solvent. After the toluene was distilled off under reduced pressure, the residual oily substance was distilled under reduced pressure twice. Boiling point 170 ℃ / 3mmHg Yield 14g
(Yield 45%).

Example 2 Preparation of 1,1-difluoro-4- (trans-4-pentylcyclohexyl) cyclohexane ((Formula I) where R = C5H11-, n = 1, X = F) 3.1 g of 1,1-dichloro-4- (trans-4-pentylcyclohexyl) cyclohexane was dissolved in 100 ml of dry methylene chloride, and the mixture was cooled to 0 ° C under a nitrogen stream.
While vigorously stirring, 5 g of silver tetrafluoroborate was added. After reacting for 1 hour and further for 3 hours at room temperature, the reaction solution was filtered under reduced pressure on a funnel having a tightly packed layer of activated alumina.

The filter cake was washed with 2N sodium hydroxide for 2 days and then with water until neutral. After drying over anhydrous sodium sulfate, methylene chloride was distilled off, and the remaining oily substance was reduced under reduced pressure to 2
Distilled once. The boiling point was 160 ° C./3 mmHg, and the yield was 0.9 g (yield 33%).

Example 3 Instead of 4- (trans-4-pentylcyclohexyl) cyclohexanone in Example 1, 4- [trans-4-
(Trans-4-propylcyclohexyl) cyclohexyl] cyclohexanone was used to prepare 1,1-dichloro-4-
[Trans-4- (trans-4-propylcyclohexyl) cyclohexyl] cyclohexane can be produced.

Example 4 In Example 2, 1,1-dichloro-4- (trans-pentylcyclohexyl) cyclohexane was replaced by 1,1-dichloro-4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] cyclohexane. It can be used to produce 1,1-difluoro-4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] cyclohexane.

Application Example 1 Liquid crystal composition (A) trans-4-propyl- (4-cyanophenyl) cyclohexane 24% by weight trans-4-pentyl- (4-cyanophenyl) cyclohexane 36% by weight trans-4-heptyl- (4- Cyanophenyl) cyclohexane 25% by weight trans-4-pentyl- (4-cyanobiphenyl) cyclohexane 15% by weight The liquid crystal composition (A) has a N-1 point of 72.3 ° C. and Δε.
Is +11.3, the viscosity at 20 ° C. is 26.8 cp, and Δn is 0.135. As a liquid crystal cell, a substrate having tin oxide transparent electrodes coated with silicon oxide and subjected to a rubbing treatment was made to face each other and assembled. When the distance between the electrodes was 10 μm, the above liquid crystal composition (A) was sealed and the characteristics were measured at 20 ° C., and the threshold voltage (Vth) was 1.83V.

N-1 point of a composition prepared by dissolving 5% by weight of 1,1-dichloro-4- (trans-4-pentylcyclohexyl) cyclohexane prepared in Example 1 of the present invention in 95% by weight of this liquid crystal composition (A). Was 57.1 ° C, Δε was +10.7, the viscosity at 20 ° C was 27.5 cp, and Δn was 0.124. The Vth was 1.50 V in the characteristics of the liquid crystal cell filled with the same composition as described above using the composition. Even though the liquid crystal composition Δε becomes small in this way, Vth is lowered, and Δn
Was able to be reduced.

Application Example 2 N- of a composition obtained by dissolving 5% by weight of 1,1-difluoro-4- (trans-4-pentylcyclohexyl) cyclohexane prepared in Example 2 of the present invention in 95% by weight of the liquid crystal composition (A). One point is 57.5 ° C, Δε is +10.6, the viscosity at 20 ° C is 26.5 cp, and Δn is 0.125. The Vth was 1.50 V in the characteristics of the liquid crystal cell filled with the same composition as described above using the composition. In this way, the viscosity of the liquid crystal composition was decreased, Δn was decreased, and Vth could be decreased even though Δε was decreased.

Claims (2)

(57) [Claims] 1. A general formula (Wherein n represents 1 or 2, X represents F or Cl, and R represents a straight-chain or branched alkyl group having 1 to 15 carbon atoms). A halogenocyclohexane derivative. 2. General formula (Wherein n represents 1 or 2, X represents F or Cl, and R represents a straight-chain or branched alkyl group having 1 to 15 carbon atoms). A liquid crystal composition containing at least one halogenocyclohexane derivative.