JP2525213B2 - Ester derivative of α-methylallylphenol - Google Patents

Description

TECHNICAL FIELD The present invention relates to a novel ester compound and a liquid crystal composition containing the compound.

[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 dielectric 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, a liquid crystal phase using a nematic liquid crystal is most widely used.

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

At present, there is no single liquid crystal substance that satisfies such conditions, and several types of liquid crystal substances or non-liquid crystal substances are mixed for practical use. These substances are water,
It is required to be stable against light, heat, air, etc.

In recent years, multi-digit drive display of display elements has been desired, but since the display quality is inferior in the conventional TN type method, a new series of super twist nematic type display elements (abbreviated as STN)
Was proposed by M. Schadt et al. (Appl.Phys.
Lett., 50 , 236 (1987)), and has excellent quality even in multi-digit drive display.

The liquid crystal properties desired for this method are large K ₃ / K ₁ and K ₂ / K _1.
It is desired that K ₁ is small and Δε / ε⊥ is small (M.
Schadt et al., Society for Information Display Internati
onal Symposium Digest of Technical Papars Vol.X VI
II New Orleans, Louisiana May 12-14, (1987) 372-37
Five).

INDUSTRIAL APPLICABILITY The present invention is a compound having a large K ₃ / K ₁ and excellent compatibility, and is a compound suitable for the above-mentioned STN type display element, and an ester compound having three or more rings exhibits a liquid crystal phase in a wide temperature range up to a high temperature. Therefore, it is possible to raise the NI point of the liquid crystal composition.

As is clear from the above description, an object of the present invention is to provide a novel compound useful as a liquid crystal composition. Another object is to provide a liquid crystal composition containing the compound.

[Means for Solving Problems] The present invention (second invention) is represented by the general formula (In the above formula, R ¹ and R ² are each linear or branched carbon atoms 1
To 15 alkyl groups or alkoxy groups, 1 represents 0 or 1. A liquid crystal composition comprising an ester compound represented by the formula (1) selected from the group consisting of: and a compound containing the ester compound.

The liquid crystal composition of the present invention is characterized by containing the above-mentioned ester compound of the present invention. 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 type, Schiff base type, biphenyl type, phenylcyclohexane type, and heterocyclic type liquid crystal compounds.

The compounds of the present invention can be prepared as shown by the reaction of the formula:

(In the above formula, R ¹ , -A-, l, R ² are the same as above) That is, the 4-crokeloxyphenyl ether derivative is boiled under reflux in diethylaniline to give the 2- (α-methylallyl) phenol derivative. Manufactured. This 2- (α
The -methylallyl) phenol derivative was reacted with the carboxylic acid chloride corresponding to the desired product in the presence of pyridine to produce the desired compound.

EFFECTS OF THE INVENTION The compound of the present invention has good compatibility with many other liquid crystal compounds, that is, liquid crystal compounds of ester type, Schiff base type, biphenyl type, phenylcyclohexane type, heterocyclic type, etc. The NI point can be raised by adding a small amount of a compound having a ring or more to the liquid crystal composition.

Moreover, when the compound of the present invention is added to the liquid crystal composition, K ₃ / K ₁
It is a compound suitable for a liquid crystal composition for STN type display devices, since the value of can be increased.

[Examples] The compounds of the present invention will be described in more detail by the examples described below.

Example 1 Preparation of 2- (α-methylallyl) -4-hexyloxyphenol: 1-crotyloxy-4-hexyloxybenzene 2
4.8 g (0.1 mol) was dissolved in 40 ml of N, N-diethylaniline and refluxed under nitrogen atmosphere for 8 hours. After cooling, toluene 100m
l was added and transferred to a separating funnel. After the toluene layer was extracted 3 times with 100 ml of 6N hydrochloric acid, the toluene layer was washed until the washing liquid became neutral. The toluene layer was dried over anhydrous sodium sulfate and then filtered, and toluene was distilled off under reduced pressure. The remaining extract was vacuum distilled. Boiling point 130 ° C / 5mmHg, yield 13.5g (yield 54%) Similarly, from 1-crotyloxy-4-pentylbenzene to 2- (α-methylallyl) -4-pentylphenol boiling point 120 ° C / 5mmHg, 1-crotyloxy-4 2 from-(trans-4-heptylcyclohexyl) benzene
-(Α-Meryrylallyl) -4- (trans-4-heptylcyclohexyl) phenol Boiling point 140 ° C / 5mmHg, 1-
2 from crotyloxy-4- [trans-4- (transpropylcyclohexyl) cycloroxyl] benzene
-(Α-methylallyl) -4- [trans (trans-
4-Propylcyclohexyl) cyclohexyl] phenol melting point 103.5-104.5 ° C was prepared.

Example 2 Trans-4- (trans-4-propylcyclohexyl) cyclohexanecarboxylic acid 2- (α-methylallyl) -4- (trans-4-heptylcyclohexyl)
Production of phenyl ester: 2.7 g (0.01 mol) of trans-4- (trans-4-propylcyclohexyl) cyclohexanecarboxylic acid chloride was added to 2- (α-methylallyl) -4- (trans-4).
-Heptylcyclohexyl) phenyl ester 3.3 g (0.
(01 mol) was dissolved in 20 ml of pyridine, 100 ml of toluene was added, and the mixture was stirred well. After standing overnight, the reaction mixture is washed with water 1
The mixture was poured into 00 ml, and the toluene layer was separated, washed with 6N hydrochloric acid, 2N sodium hydroxide solution, water, and then dried over anhydrous sodium sulfate.

Toluene was distilled off from this toluene solution, and the remaining oily substance was subjected to an activated alumina column treatment using toluene as a solvent. Then recrystallize with ethanol to obtain the desired trans-4- (trans-4-propylcyclohexyl)
Cyclohexanecarboxylic acid 2- (α-methylallyl)-
4- (trans-4-heptylcyclohexyl) phenyl ester was prepared. CN point 67.5 to 68.5 ° C, NI point 148.9
° C. Yield 3.5 g (yield 62%) Examples 3 to 6 In place of trans-4- (trans-4-propylcyclohexyl) cyclohexanecarboxylic acid chloride in Example 2, the corresponding carboxylic acid chloride was replaced with 2- (α
Various ester compounds were prepared using the corresponding 2- (α-methylallyl) -4-substituted phenols instead of -methylallyl) -4- (trans-4-heptylcyclohexyl) phenol. The results are shown in Table 1 together with Example 2.

Application Example 1 trans-4-propyl- (4-cyanophenyl) cyclohexane 30% by weight trans-4-pentyl- (4-cyanophenyl) cyclohexane 40% by weight trans-4-heptyl- (4-cyanophenyl) cyclohexane 30% by weight % Of the liquid crystal mixture (A) with a composition of 52.1 ° C. and Δε of 1
1.2, viscosity at 20 ℃ is 23.4cp, Δn is 0.119, k ₃ / k ₁
Is 1.82. As a liquid crystal cell, a substrate having a tin oxide transparent electrode coated with silicon oxide and rubbed was assembled to face each other, and an electrode distance between electrodes was 10 μm, and the above liquid crystal composition (A) was sealed therein. When Vth was measured, it was 1.55V.

85% by weight of this liquid crystal composition (A) was added with trans-4- (trans-4-propylcyclohexyl) cyclohexanecarboxylic acid 2- (α-methylallyl) -4- (trans-4-heptyl) prepared in Example 2 of the present invention. Of a liquid crystal composition in which 15% by weight of cyclohexyl) phenyl ester is dissolved
NI point is 63.5 ℃, Δε is 9.4, Δn is 0.122, Vth is 1.66V.
Met. k ₃ / k ₁ increased to 1.95, which was suitable for STN and was able to raise the NI point.

Application Example 2 Trans-4-propylcyclohexanecarboxylic acid 2 prepared in Example 4 of the present invention was added to 85% by weight of the liquid crystal composition (A).
The composition in which 15% by weight of-(α-methylallyl) -4- (trans-4-pentylcyclohexyl) phenyl ester was dissolved had an NI point of 65.4 ° C, Δε of 9.6, Δn of 0.123 and V.
th was 1.66V. k ₃ / k ₁ was 1.93, which was suitable for STN and was able to raise the NI point.

Application Example 3 Trans-4- (trans-4-pentylcyclohexyl) prepared in Example 6 in 90% by weight of the liquid crystal mixture (A).
Cyclohexane carvone 2- (α-methylallyl) -4-
The composition in which 15% by weight of [trans-4- (trans-4-propylcyclohexyl) cyclohexyl] phenyl ester was dissolved had an NI point of 75 ° C., Δε of 9.7, and Δn of 0.12.
2, Vth was 1.65V. Moreover, k ₃ / k ₁ was 1.91, which was suitable for STN and was able to raise the NI point.

Continuation of front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C07C 69/773 C07C 69/773 69/92 69/92 69/94 69/94 C09K 19/20 9279-4H C09K 19/20 19/30 19/30 19/32 19/32 G02F 1/13 500 G02F 1/13 500

Claims (2)

(57) [Claims] 1. A general formula (In the above formula, R ¹ and R ² are each linear or branched carbon atoms 1
To 15 alkyl groups or alkoxy groups, 1 represents 0 or 1. Ester compound represented by one) selected from the group consisting of 2. General formula (In the above formula, R ¹ and R ² are each linear or branched carbon atoms 1
To 15 alkyl groups or alkoxy groups, 1 represents 0 or 1. A liquid crystal composition comprising an ester compound represented by the formula (1) selected from the group consisting of: