JPH03184932A - Alkenyloxyallylbenzenes - Google Patents

Abstract

NEW MATERIAL:Alkenyloxyallylbenzenes expressed by formula I (R<1> is straight- chain or branched 1-15C alkenyl; R<2> is straight-chain or branched 1-15C alkyl; 1 is 1 or 2). EXAMPLE:1-Allyloxy-2-allyl-4-(trans-4-propylcyclohexyl-trans-4-cyclohe xyl)benzene. USE:A compound of liquid crystal compositions. PREPARATION:For example, allyl bromide expressed by formula II is reacted with a 4-alkylcychohexylphenol or 4-alkylbicyclohexylphenol expressed by formula III and potassium hydroxide in ethanol to provide a phenyl allyl ether derivative expressed by formula IV, which is then heated in dimethylaniline while being refluxed to afford a 2-ally-4-alkylcyclohexylphenol according to the Claisen rearrangement. The resultant compound is subsequently reacted with an alkenyl bromide to provide the alkenyloxyallylbnnenzenes expressed by formula I.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to novel alkenyloxyallylbenzenes and liquid crystal compositions containing the compounds as active ingredients.

[Conventional technology]

Display elements using liquid crystals are widely used in watches, calculators, etc. These liquid crystal display elements utilize optical anisotropy and dielectric anisotropy of liquid crystal substances. There are three types of liquid crystal phases: nematic liquid crystal phase, smectic liquid crystal phase, and cholesteric liquid crystal phase. Among these, those using nematic liquid crystal are most widely put into practical use, and applications of smectic liquid crystal are being actively developed.

There are display elements such as TN (twisted nematic) type, DS (dynamic scattering) type, guest-host type, and DAP type, which correspond to the electro-optical effect applied to liquid crystal displays, and each type is used. It is desirable that the liquid crystal material used exhibits a liquid crystal phase over as wide a natural temperature range as possible.

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

In recent years, there has been a desire to increase the size of display elements, and large-screen displays using laser light writing using smectic liquid crystals have been developed.
Kahn, P. J., Appl Phys.

Lett, 22.111-113 (1973))
suggested. The liquid crystal compound used for this purpose must undergo a phase transition in the following order: smectic phase -> nematic phase <-> isotropic liquid.

On the other hand, the display quality of the conventional TN type method is inferior, so
A new series of 5TN (super twist) type display elements are available from M, Shut, F, Leanfoots (Appl, Phy
It was developed by John S., Lett, 50.286 (1987)), and the display quality remains the same even when it is enlarged.

The properties of the liquid crystal desired for this method are as follows:
It is desired that K2/Kl is small and Δε/ε□ is small (M, 5chadt, P, LeenhoutsS
Society for Information
Display International
Symposium Digest of T
electrical Papers Vol, X Mi
ll New 0rleans, Lousjana
May 12-14° (1987) 372-37
5).

Here, 1 is the elastic constant of spreading, R2 is the elastic constant of twisting, and R3 is the elastic constant of bending, which can be determined from the threshold voltage when a magnetic field or electric field is applied to a cell oriented in a negative direction.

If ε□ is the permittivity in the direction perpendicular to the orientation vector, and ε〃 is the permittivity in the direction parallel to the orientation vector, then Δε−ε〃
−ε□, and exhibits dielectric anisotropy.

[Problem to be solved by the invention]

The purpose of the present invention is to increase K3/ by 1 without increasing Δn so much.
It is an object of the present invention to provide a novel compound which has a large compatibility and excellent compatibility, which can be used in the above-mentioned STN type non-display element, and which is useful as a liquid crystal composition. Another object is to provide a liquid crystal composition containing the compound.

However, Δn is nn −1], which is the difference between the refractive index in the direction parallel to the orientation vector and the refractive index in the perpendicular direction.

[Means to solve the problem]

The present invention is based on (1) the general formula (in the above formula, R1 is a straight chain or branched alkenyl group having 1 to 15 carbon atoms;
-15 alkyl groups, and g represents 1 or 2); (2) a liquid crystal composition containing at least one alkenyloxyallylbenzene described in (1) above; It is.

Other components 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, for example, ester-based, -Schiff base-based, biphenyl-based, phenylcyclohexane-based, and heterocyclic-based liquid crystal compounds. .

The method for producing the compound of the present invention includes, for example, the following formula (II) (m)
This is shown by the reaction of

(In the above formula, R, R2, and D are the same as above, EtOH represents ethanol, PhNMe2 represents dimethylaniline, and DMF represents N,N-dimethylformamide.) That is, allyl bromide and 4- Alkylcyclohexylphenol (Q=1) or 4-alkylbicyclohexylphenol (Ill-2) is reacted with potassium hydroxide in ethanol to form a phenylallyl ether, and then heated under reflux in dimethylaniline, Claisen rearrangement yields 2allyl-4-alkylcyclohexylphenol.

This allylphenol and alkenyl bromide are N.

A reaction was carried out with anhydrous potassium carbonate in N-dimethylformamide (hereinafter abbreviated as DMF) to obtain the target alkenyloxyallylbenzenes.

〔Example〕

The present invention will be explained in more detail with reference to Examples below.
The present invention is not limited in any way by this example.

(Example 1) 1-allyloxy-2-allyl-4-(trans-4-
Production of propylcyclohexyl-trans-4cyclohexyl)benzene.

2 (Formula I, R-CH=CHCH2-, R-C3H7-1N
= 2) 1-hydroxy-2-allyl-4-(trans-4-propylcyclohexyl-trans-4-cyclohexyl)
200 ml of DMF was added to 3.4 g (0.01 mol) of benzene, and 50 g of anhydrous potassium carbonate was added thereto. Allyl bromide 3.6 g (0.03 mol) while stirring
was added, and the reaction was carried out at 80°C for 12 hours.

After the reaction was completed, water was added to the reaction solution, and the precipitated oil was extracted with toluene. The toluene layer was washed with 2N sodium hydroxide and then with water until neutral.

After drying the toluene layer with anhydrous sodium sulfate, toluene was distilled off under reduced pressure. The remaining crystals were recrystallized from ethanol-〇-hexane. Crystal smectic A point 37℃
, smectic A-nematic point 54.9°C, nematic clearing point 65.1°C. The yield was 2.7 g (yield 67%).

(Application example 1) trans-4-propyl-(4-cyanophenyl)cyclohexane 30% by weight trans-4-pentyl-(4-cyanophenyl)cyclohexane
The N-I point of liquid crystal mixture (A) having a composition of 40% by weight of trans-4-hebutyl-(4-cyanophenyl)cyclohexane and 30% by weight is 52.1°C.
, Δε is 11.2.The viscosity at 20℃ is 23,4, Δ
n is 0.119 and K/KL is 1.82. A liquid crystal cell was prepared in which substrates coated with silicon oxide and having transparent electrodes of rubbed tin oxide were assembled to face each other, and the distance between the electrodes was 10 μm, and the above liquid crystal composition (A) was sealed. When its characteristics were measured at 20°C, the threshold voltage (hereinafter abbreviated as vth) was 1,
．． It was 55V.

The present invention was added to 85% by weight of this liquid crystal composition (A) - 1-allyloxy-2-allyl 4- produced in Example 1.
(trans-4-propylcyclohexyltrans-4
The N-1 point of the composition in which 15% by weight of -cyclohexyl)benzene is dissolved is 52.4°C, Δε is 9.5, and Δn is 0.
120, vth was 1.60V.

Further, K/1 is large as 1.92, and the N-I point can also be increased, making it suitable for STN applications.

(Example 2) DMF and CHCH-CHCH2Br were added to react. The obtained compound is, and the crystal-nematic (C-N) point of this compound is 66.5-67.5°C, and the nematic transparent (N-I
) point was 80.4°C.

0 [Effects of the Invention] The compound of the present invention has good compatibility with many other liquid crystal compounds, such as ester-based, Schiff base-based, biphenyl-based, phenylcyclohexane-based, and heterocyclic-based liquid crystal compounds. By adding the compound to the liquid crystal composition,
Since the value of K 3 / K t can be increased without increasing Δn or the threshold voltage that much, S
A compound suitable for liquid crystal compositions for TN type display elements,
In addition, the 1-alkenyloxy-2-allyl-4-trans-4-(trans-4-propylcyclohexyl)cyclohexylbenzene produced here undergoes a phase transition from smectic A phase←→nematic phase→liquid, so it forms smectic A phase. It is suitable for laser writing type display devices using.

Claims (1)

[Claims] 1. General formula ▲ There are mathematical formulas, chemical formulas, tables, etc. ▼ (I
) (In the above formula, R^1 is a straight chain or branched alkenyl group having 1 to 15 carbon atoms, R^2 is a straight chain or branched alkyl group having 1 to 15 carbon atoms, and l represents 1 or 2). 2. A liquid crystal composition containing at least one alkenyloxyallylbenzene according to claim 1.