JP2829438B2 - 3-halogeno-4-bicyclohexylbenzotrifluoride derivative - Google Patents

Description

The present invention relates to a novel 1-trifluoromethyl-3-halogeno-4- [trans-4- (trans-4-alkylcyclohexyl) cyclohexyl] benzene and a method for producing the same. The present invention relates to a liquid crystal composition containing a compound as an active ingredient.

[Conventional technology]

Liquid crystal display devices use the optical anisotropy and dielectric anisotropy of liquid crystal materials.
There are various types of liquid crystal materials, such as a liquid crystal type (twisted nematic type), a DS type (dynamic scattering type), a guest-host type, and a DAP type. However, it is common that all liquid crystal substances need to be stable to moisture, air, heat, light, etc., and exhibit a liquid crystal phase in a temperature range as wide as possible around room temperature. It is necessary to have an optimum value of dielectric anisotropy (Δε) which differs depending on the type. However, at present, no single compound satisfies such conditions, and at present, a liquid crystal composition obtained by mixing several types of liquid crystal compounds and non-liquid crystal compounds is used. Recently, a liquid crystal display element having a higher display quality is required. To meet such demands, display devices using TET (thin film transistor) have been developed. The liquid crystal required for this TET type liquid crystal display element is a compound having a large specific resistance value.
As a general liquid crystal compound, a compound having a cyano group is often used. It is known that a cyano group is decomposed when used in a TFT-type liquid crystal display device to which a high voltage is applied. The present inventors have previously disclosed in JP-A-57-64626 a compound of the following formula: Was disclosed. Δε (electrical conductivity anisotropy value) of this compound is about +2 times. Further, the present inventors have disclosed Japanese Patent Application Laid-Open No. 59-78129.
Compound of the formula Was disclosed. Δε of this compound was about +8.

Adjustment of the operating voltage is required for liquid crystal display devices, especially devices using TET. Therefore, the components of the liquid crystal used for these compounds have various Δε values required for them and are chemically stable compounds. Is required.

[Problems to be solved by the invention]

An object of the present invention is to provide a liquid crystal compound and a liquid crystal composition which are low in viscosity, have a large Δε of about +6, and are chemically stable.

[Means for solving the problem]

The present invention has the general formula (Wherein, R represents a straight-chain or branched alkyl group having 1 to 15 carbon atoms, X represents F or Cl) 1-trifluoromethyl-3-halogeno-
A liquid crystal composition containing 4- [trans-4- (trans-4-alkylcyclohexyl) cyclohexyl] benzene and the compound as an active ingredient.

The compound of the present invention exhibits a relatively large positive dielectric anisotropy value, has a low viscosity, is chemically stable, and is a compound that is stable to heat, air, moisture, light, etc. It is a compound extremely useful for obtaining a liquid crystal composition used for a liquid crystal display device.

Next, a method for producing the compound of the present invention will be described. 3-Halogeno-4-bromobenzotrifluoride is reacted with magnesium powder in a tetrahydrofuran solvent (abbreviated as THF),
A Grignard reagent was prepared. Next, this Grignard reagent was reacted with trans-4- (trans-4-alkylcyclohexyl) cyclohexanone to produce an alcohol (II). This (II) is subjected to a dehydration reaction using p-toluenesulfonic acid as a catalyst to give 1-trifluoromethyl-3-halogeno-4- [4- (trans-4-alkylcyclohexyl) cyclohexen-1-yl] benzene ( III) was prepared. Then, the desired 1-trifluoromethyl- was subjected to catalytic reduction under pressure using a platinum-carbon catalyst.
3-halogeno-4- [trans-4- (trans-4-
[Alkylcyclohexyl) cyclohexyl] benzene (I) was produced.

(Action and Effect of the Present Invention) The compound of the present invention has good compatibility with many other liquid crystal compounds, that is, liquid crystal compounds such as ester type, Schiff base type, biphenyl type, phenylcyclohexane type and heterocyclic type. By adding the compound of the present invention as a component of the liquid crystal composition, the magnitude of Δε can be adjusted without increasing the viscosity so much, and a liquid crystal composition having various threshold voltages can be obtained. Also, the NI point of the composition can be increased.

Therefore, it can be said that the compound of the present invention is a compound particularly suitable as a component of a liquid crystal composition for a TFT type liquid crystal device.

〔Example〕

Hereinafter, the production method and use examples of the compound of the present invention will be described in more detail with reference to Examples.

Example 1 [1-trifluoromethyl-3-fluoro-4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] benzene (wherein R = C ₃ H ₇
-, X = F)] 2.6 g (0.108 mol) of magnesium powder and 10 ml of tetrahydrofuran were placed in a flask, and 3-fluoro-4 was added thereto.
A solution of 25.0 g (0.103 mol) of -bromobenzotrifluoride in 50 ml of tetrahydrofuran was added dropwise over 30 minutes under ice-cooling, followed by reaction at room temperature. The result is 2-
Fluoro-4-trifluoromethylphenylmagnesium bromide. This Grignard reagent is added to 4- (trans-4-propylcyclohexyl) cyclohexanone
A solution of 24.0 g (0.108 mol) of tetrahydrofuran (50 ml) was added dropwise over 40 minutes while maintaining the temperature at 5 ° C. or lower under ice-cooling. After completion of the reaction, ice-cooled 2N-hydrochloric acid 300 ml
I fell into the navel. The precipitated oil was extracted with 200 ml of toluene, and the toluene layer was washed with water until neutral. Thereafter, the solvent was distilled off under reduced pressure to obtain a yellow liquid. This is 1-trifluoromethyl-3-fluoro-4- [4- (trans-
4-propylcyclohexyl) cyclohexyl-1-ol] benzene (yield 77%).

Next, the 1-trifluoromethyl-3-fluoro-
4- [4- (trans-4-propylcyclohexyl)
Cyclohexyl-1-ol] benzene was directly dissolved in 100 ml of toluene without purification, 1.0 g of p-toluenesulfonic acid was added, and the mixture was heated under reflux for 3 hours to perform a dehydration reaction.
After the reaction was completed, the reaction solution was allowed to cool to room temperature, and the reaction solution was washed with 2N-sodium hydroxide, and then washed with water until neutral. Thereafter, the solvent was distilled off under reduced pressure to obtain a brown oily substance. This oil was recrystallized from a mixed solution of ethanol and normal heptane to obtain colorless crystals. This is 1-trifluoromethyl-3-fluoro-4- [4- (trans-4-propylcyclohexyl) cyclohexen-1-yl] benzene (yield 10 g, 35%, CN point 78.8-79.9 ° C, N
I point 91.6-91.7 ° C).

Next, the 1-trifluoromethyl-3-fluoro-
4- [4- (trans-4-propylcyclohexyl)
Cyclohexen-1-yl] benzene in ethanol 150m
l and toluene (50 ml).
A carbon catalyst was added, and a catalytic reduction reaction was performed at 30 ° C. and a hydrogen pressure of 5 to 10 kg / cm ² . After completion of the reaction, the catalyst was separated, the solvent was distilled off under reduced pressure, and the remaining oil was recrystallized from ethanol to obtain colorless crystals. This is 1-trifluoromethyl-3-fluoro-4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] benzene (yield
5 g, yield 45%, C-SB point 47.2-47.9 ° C, SB-N point 91.4-
92.0 ° C, NI point 94.1 to 94.5 ° C).

Using 4- (trans-4-alkylcyclohexyl) cyclohexanone having a different alkyl group instead of 4- (trans-4-propylcyclohexyl) cyclohexanone, the following 1-trifluoromethyl-3-fluoro-
4- [trans-4- (trans-4-alkylcyclohexyl) cyclohexyl] benzene can be produced.

1-trifluoromethyl-3-fluoro-4- [trans-4- (trans-4-methylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-fluoro-4- [trans-4- (trans-4 -Ethylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-fluoro-4- [trans-4- (trans-4-butylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-fluoro-4- [ Trans-4- (trans-4-pentylcyclohexyl)
Cyclohexyl] benzene, 1-trifluoromethyl-3-fluoro-4- [trans-4- (trans-4-hexylcyclohexyl)
Cyclohexyl] benzene, 1-trifluoromethyl-3-fluoro-4- [trans-4- (trans-4-heptylcyclohexyl)
Cyclohexyl] benzene, 1-trifluoromethyl-3-fluoro-4- [trans-4- (trans-4-octylcyclohexyl)
Cyclohexyl] benzene, 1-trifluoromethyl-3-fluoro-4- [trans-4- (trans-4-nonylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-fluoro-4- [trans-4- (Trans-4-decylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-fluoro-4- [trans-4- (trans-4-undecylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3- Fluoro-4- [trans-4- (trans-4-dodecylcyclohexyl)
[Cyclohexyl] benzene, 1-trifluoromethyl-3-fluoro-4- [trans-4- (trans-4-tridecylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-fluoro-4- [trans-4 -(Trans-4-tetradecylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-fluoro-4- [trans-4- (trans-4-pentadecylcyclohexyl) cyclohexyl] benzene.

Example 2 [1-trifluoromethyl-3-chloro-4- [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] benzene (where R = C ₃ H ₇ , X =
Production of Cl)] In the same manner as in Example 1, 3-chloro-4-bromobenzotrichloride was used instead of 3-fluoro-4-bromobenzotrifluoride to give 1-trifluoromethyl- 3-chloro-4- [trans-4- (trans-4
-Propylcyclohexyl) cyclohexyl] benzene was obtained.

The following 1-trifluoromethyl-3 was similarly prepared using 4- (trans-4-alkylcyclohexyl) cyclohexanone having a different alkyl group instead of 4- (trans-4-propylcyclohexyl) cyclohexanone.
-Chloro-4- [trans-4- (trans-4-alkylcyclohexyl) cyclohexyl] benzene can be produced.

1-trifluoromethyl-3-chloro-4- [trans-4- (trans-4-methylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-chloro-4- [trans-4- (trans-4 -Ethylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-chloro-4- [trans-4- (trans-4-butylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-chloro-4- [ Trans-4- (trans-4-pentylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-chloro-4- [trans-4- (trans-4-hexylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl -3-chloro-4- [trans-4- ( Lance-4-heptylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-chloro-4- [trans-4- (trans-4-octylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-chloro- 4- [trans-4- (trans-4-nonylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-chloro-4- [trans-4- (trans-4-decylcyclohexyl) cyclohexyl] benzene, 1- Trifluoromethyl-3-chloro-4- [trans-4- (trans-4-undecylcyclohexyl)
Cyclohexyl] benzene, 1-trifluoromethyl-3-chloro-4- [trans-4- (trans-4-dodecylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-chloro-4- [trans-4- (Trans-4-tridecylcyclohexyl)
Cyclohexyl] benzene, 1-trifluoromethyl-3-chloro-4- [trans-4- (trans-4-tetradecylcyclohexyl) cyclohexyl] benzene, 1-trifluoromethyl-3-chloro-4- [trans-4 -(Trans-4-pentadecylcyclohexyl) cyclohexyl] benzene.

Use Example 3 (Composition) trans-4-propyl- (4'-cyanophenyl)
Cyclohexane 28% (weight, same hereafter) trans-4-pentyl- (4'-cyanophenyl)
Cyclohexane 42% trans-4-heptyl- (4'-cyanophenyl)
Nematic liquid crystal of a liquid crystal composition having a composition of 30% cyclohexane-clearing point is 52 ° C
It is. Although the liquid crystal composition was sealed in a TN cell (twisted nematic cell) with a cell thickness of 10 μm, the operating threshold voltage was
1.60V, Δε is +10.7, Δn is 0.119, and viscosity is 2 at 20 ° C.
It was 1.7 mPas · s.

In 85 parts of this liquid crystal composition, 1-trifluoromethyl-3-fluoro-4- [trans-4- produced in Example 1 was used.
(Trans-4-propylcyclohexyl) cyclohexyl] Nematic of liquid crystal composition to which 15 parts of benzene was added
The clearing point was 55 ° C. and Δε was +10.0. The threshold voltage is
1.58 V, Δn was not much different from 0.115, and the viscosity was 2
5.3 mPas · s, and the NI point could be increased without increasing the viscosity so much.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-2-44290 (JP, A) JP-A-2-44289 (JP, A) (58) Fields investigated (Int.Cl. ⁶ , DB name) C07C 25/18 C09K 19/30 C09K 19/42 G02F 1/13 CA (STN)

Claims (2)

(57) [Claims] (1) General formula (Wherein R represents hydrogen or a linear or branched alkyl group having 1 to 15 carbon atoms, and X represents F or Cl) 1-trifluoromethyl-3-halogeno-
4- [trans-4- (trans-4-alkylcyclohexyl) cyclohexyl] benzene. 2. A liquid crystal composition comprising at least one compound according to claim 1.