JPS6034932A - Ester of dihalogenophenol - Google Patents

Abstract

NEW MATERIAL:An ester of 4-substituted benzoic acid dihalogenophenol shown by the formula I (R is 1-10C alkyl or alkoxy; ring A is group shown by the formula VI or fomula VII; X, Y, and Z are F, Cl OR H, and two of X, Y, and Z are halogen). EXAMPLE:4-(trans-4-Butylcyclohexanoyloxy)benzoic acid-2-chloro-4-fluorophenyl ester. USE:One component for a liquid crystal composition. A liquid crystal having positive dielectric anisotropy, showing a liquid crystal phase in a wide temperature range, capable of driving a display element at low voltage. PREPARATION:4-Hydroxybenzoic acid shown by the formula II is reacted with a dihalogenophenol shown by the formula III in xylene in the presence of a catalyst of boric acid and sulfuric acid to give a 4-hydroxybenzoic acid-dihalogenophenyl ester shown by the formula IV, it is then reacted with a carboxylic acid chloride shown by the formula V in the presence of pyridine, to give a compound shown by the formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel liquid crystal material having positive dielectric anisotropy and a liquid crystal composition containing the same.

Display elements using liquid crystals are widely used in time openings, desks, etc. This liquid crystal display element utilizes the optical anisotropy and dielectric anisotropy of liquid crystal q3/J quality, and the liquid crystal phases include a nematic liquid crystal phase, a smectinic liquid crystal phase, and a cholesteric liquid crystal phase. The one used is the one most widely put into practical use. That is, they include TN (twisted nematic) type, DS (dynamic scattering type), guest-host type, DAP type, etc., and the properties required of the liquid crystal materials used for each type are different. It is desirable that the liquid crystal materials that can be used in these display elements exhibit a liquid crystal phase over as wide a temperature range as possible in nature.Currently, there is no single material that satisfies such conditions, and several types of liquid crystal materials or non-liquid crystal materials are available. It is put into practical use by mixing liquid crystal materials. These substances must be stable against moisture, light, heat, air, etc. f:
It is desirable that the required threshold voltage and saturation voltage for driving the display element be as low as possible.

An object of the present invention is to provide a novel liquid crystal compound that exhibits a liquid crystal phase over a wide temperature range and is suitable as a component of a liquid crystal composition that can drive a display element at low voltage.

That is, the present invention relates to the general formula (in the above formula, R represents an alkyl group or alkoxy group having 1 to 10 carbon atoms, and the cap is K) or (y, and x, y, and z are F, Ct, or H) and two of X, Y, and Z are halogen atoms.) Dihalogenophenol esters of 4-substituted benzoic acid represented by It is a thing.

The compound of the present invention can be used at the operating temperature of a liquid crystal display device using a liquid crystal composition prepared by mixing many other liquid crystal compounds, such as ester-based, Schiff base-based, biphenyl-based, phenylcyclohexane-based, and heterocyclic liquid crystal compounds. It is possible to widen the range and lower the driving voltage.

The compounds of the present invention are produced by the method described below.

W, W, Lowrance, Jr. (Te
trahedron Letters.

3453 (1971)), 4-hydroxybenzoic acid (compound (1)) and dihalogenophenol (
Compound G11)) is reacted in xylene with boric acid and sulfuric acid as catalysts to produce 4-hydroxybenzoic acid dihalogenophenyl ester (compound 't (ff)).

This is then reacted with the corresponding carboxyl modified chloride (Compound (V)) in the presence of pyridine to form the desired dihalogenophenyl ester of 4-substituted benzoic acid (Compound (I)).
can be manufactured.

The chemical formula for the above is as follows.

R()CCt )1 () (1) (In the above formula, rz, (), x, Y, and 2 are the same as above.) The compounds of the present invention will be explained in more detail with reference to Examples below.

ls Example 1 4-(trans-4-ethylcyclohexanoyloxy)benzoic acid-2-chloro-4-fluorophenyl ester C(1) where R is C2H5-+
+ l)' 0 , (Compound (II)) ttsl and 2-chloro-4-fluorophenol (Compound i+bGI
l) ) 2 3 9 f into a 24-inch flask, and after attaching a stirrer and a moisture meter, add 1.2 xylene.
4 was added, boric acid 18.6F, and 15,31 F of boric acid were added, and the mixture was heated to reflux with stirring. Refluxing was continued until no more water was present in the water meter (20 hours). After the reaction was completed, 0.84 g of xylene was distilled off under reduced pressure, cooled to room temperature, precipitated crystals = p, and washed with toluene to give 4-
Hydroxy'/benzoin&-2-chloro-4-fluorophenylnisder was obtained. After air drying, it was used directly for the next reaction.

(2) Esterification 2.0N (0,0075 mol) of 4-hydroxybenzoic acid-2-chloro-4-fluorophenyl ester described above was dissolved in 10 ml of pyridine and stirred.
1.511' (0,0085 mol) of 4-ethylcyclohexanecarboxylic acid chloride (compound Osu) was added. After the reaction, 50 ml of toluene was added and the mixture was poured into water. The toluene layer separated into layers was washed with 6N salt iiZ, 2N sodium hydroxide solution, then water, and finally dried with anhydrous sodium sulfate. The toluene was then distilled off under reduced pressure to obtain an oil, which was re-distilled with ethanol;
Purpose 11: Obtain 1.2 tons of 4-(trans-4-ethylcyclohexanoyloxy)benzoic I-j2-2-chloro-4-fluorophenyl ester, 7 tons.
. Yield t 4-hydroxybenzoic e -2-chloro-4
-10% calculated from fluorophenyl ester. The crystal-nematic point of this substance is 1152°C,
Nematic-clearing point was 128.0°C.

Examples 2 to 29 The procedure of Example 1 was followed to prepare 4-hydroxybenzoic acid v-2,4-difluorophenyl ester or 4-hydroxybenzoic acid v-2,4-difluorophenyl ester instead of 4-hydroxybenzoic acid-2-chloro-4-fluorophenyl ester. -Hydroxybenzoic acid-2-fluoro-4-chlorophenyl ester or 4-hydroxybenzoic acid-2,4-dichlorophenyl ester is 4-
Hydroxy antonym 8 [J-8-chloro-4=fluorophenyl ester or 4-hydroxybenzoic R-a, 4
- Hydrofluorophenyl ester or 4-hydroxybenzoic acid-3-fluoro-4-chlorophenyl ester or 4-hydroxybenzoic acid? jl'J'l-3,4-difluorophenyl ester (0,0075 mol) and the corresponding rucarphonic acid chloride (0,0085 mol) were completely reacted to produce a compound of formula (1). These results are shown in Table 1 together with the results of Example 1.

Hereinafter, the crystal-nematic point 7 C-N point at the phase transition point,
Smectic-nematic point is S-N point, nematic-
The isotropic liquid point is abbreviated as the N-I point, and () indicates the monotropic phase. The yield is a value calculated based on compound (g).

Table 1 Table 1 (continued) * indicates crystal-smectic point.

*Ne indicates smectic-clearing point.

Application example 1 The N-I point of liquid crystal composition (A) having the following composition is 52.1°C
The viscosity at 520°C is 23.4 cp, and the dielectric anisotropy value (hereinafter abbreviated as Δε) icj: 11.2. The optical anisotropy value (hereinafter abbreviated as Δn) is 0.119.

7.20 Prepare a silicon oxide coating for a liquid crystal cell, and fill it with a liquid crystal composition to form a liquid crystal cell.7.20
Its at ℃! The characteristics were measured and the threshold voltage (hereinafter abbreviated as vth) was 1.55V, and the saturation voltage (hereinafter abbreviated as VsaL) was 2.15V.

This liquid crystal composition + a composition in which 10 wt. The N-I point of the object is 55
, 5°C viscosity at 120°C is 27.8CI), △
ε is 1O13, △n is 0.118, Vth is 1.46V
, Vsat was 2.08V.

Application Examples 2 to 5 A composition in which 10 to 15 gI-'J"a% of the compound of formula (1) of the present invention was dissolved in 85 to 90% by weight of the liquid crystal composition (A) having the same composition as Example 30. Regarding the material, a+:+ was determined for the same question, and the results are shown in Table 2 along with the results of Application Example 1.

As described above, by using the compound of the present invention, the upper limit of the operating temperature range of the liquid crystal display crystal can be increased, and the vth%
I was able to lower Vsat.

that's all

Claims (2)

[Claims] (1) General formula (in the above formula, R represents an alkyl group or alkoxy group having 1 to 10 carbon atoms, ÷ is K) or (x, y, z are F or Ct or id I-I esters of dino-10-genophenol of 4-substituted benzoic acid, and two of x, y, and z are ).logen atoms. (2) General formula (in the above formula, R represents an alkyl group or an alkoxy group having 1 to 10 carbon atoms, (represents 0 or (y), x, y, z are F;
1 indicates that two of x, y, and z are halogen atoms. ) A liquid crystal composition comprising an ester of dihalogenophenol of 4-substituted benzoic acid represented by: