JPS59167540A - Ester derivative - Google Patents

Abstract

NEW MATERIAL:An ester derivative having 3-alpha,alpha,alpha-trifluoromethylphenolic group expressed by formula I (R is H, 1-15C alkyl and alkoxyl group; rings A and B are formulas II and III). EXAMPLE:3-alpha,alpha,alpha-Trifluorophenyl trans-4-( trans-4-propylcyclohexyl )cyclohexylcarboxylate. USE:One component in liquid crystal compositions, having a weak positive dielectric anisotropy and high clear point, capable of reducing the viscosity without reducing the clear point, and scarcely changing the threshold voltage and saturation voltage through about +1 dielectric ansotropy value with good stability to moisture, heat, light, etc. PREPARATION:A carboxylic acid chloride expressed by formula IV is reacted with a 3-alpha,alpha,alpha-trifluoromethylphenol expressed by formula V in the presence of pyridine to give the aimed compound expressed by formula I .

Description

[Detailed description of the invention] The present invention relates to a crystal substance and a liquid crystal composition containing the same.

Display elements using liquid crystals are widely used in watches, electronic clocks, etc. This liquid crystal display element utilizes the properties of optical anisotropy and dielectric anisotropy of liquid crystal materials, and there are three liquid crystal phases: i-matic liquid crystal phase, smectic liquid crystal phase, and cholesteric liquid crystal phase, among which nematic liquid crystal is used. The one that has been put into practical use is the most widely used. That is, they have TN
There are various types of liquid crystal materials, including twisted nematic (twisted nematic), DS (dynamic scattering), guest-host, and DAP types, and the properties required of the liquid crystal materials used for each type are different. It is desirable for the liquid crystal substances used in these display elements to exhibit a liquid crystal phase over as wide a range as possible in the natural world.Currently, there is no single substance that satisfies this condition, but there are several types of liquid crystal substances. Alternatively, it is used in practical use by mixing non-liquid crystal substances. These substances are required to be stable against moisture, light, heat, air, etc., and in addition, the threshold voltage and saturation voltage required to drive the display element must be as low as possible, and the response speed must be fast. It is desirable that the viscosity be as low as possible.

Furthermore, in order to widen the liquid crystal temperature range toward higher temperatures, it is necessary to use a liquid crystal substance with a high melting point as a component, but liquid crystal substances with a generally high melting point have a high viscosity If, so liquid crystal compositions containing it must also be used. Since the viscosity increases, high crystallization, e.g. 80
The response speed of liquid crystal display devices that can be used at low temperatures, especially at low and high temperatures, tends to be significantly slower. The present inventors discovered a liquid crystal substance that has low viscosity and makes it difficult for liquid crystals to precipitate when added as a component of a composition, leading to the present invention.

The present invention relates to an ester derivative having a 3-α,α,α-trifluoromethylphenol group represented by the general formula (in which R is a hydrogen atom or a carbon number of 1 to 15) and a liquid crystal containing the same. It is a composition.

The compound of the present invention has a high clearing point, for example, one of the compounds of the present invention has a trans-4-(trans-4-propylene clohequinine) point of 44.8°C. As a component of the composition, the viscosity of the composition can be lowered without appreciably lowering the nematic clearing point. Further, although the dielectric anisotropy value of the compound of the present invention is about +1, it does not change the threshold voltage and saturation voltage of the composition so much. It also has good stability against moisture, heat, light, etc.

Next, a method for producing the compound of the present invention will be described. In the presence of the corresponding carboxylic acid chloride and pyridine, 3-α, α,
React with α-trifluoromethylphenol to form the respective ester derivatives. The chemical formula shown below is as follows: The compound of the present invention will be explained in more detail with reference to Examples.

In each work, the crystal phase is abbreviated as C, the smectic phase as Sm, the transparent phase as I, the melting point as m, p, and the nematic phase as N.

Example 1 [4-pentylbiphenyl-4'-carboxylic acid-3-
Production of α,α,α-trifluoromethylphenyl ester] 3-α,α,α-trifluoromethylphenol 1.6
7 is pyridine 107! 4. Dissolve in the water and shake well.
-pentylbiphenyl-4'-carboxylic acid chloride 2
．． 91 was added. Immediately after leaving the reaction solution overnight, it was poured into 100 ml of water, and the oil was extracted with 100 ml of toluene. The toluene layer was washed with 5N-HCJ, then with 2N-NaOH, and then washed with water until neutral, filtered, and the toluene was distilled off under reduced pressure. The remaining crystals are recrystallized with ethanol to obtain the target product, 4-pentylbiphenyl-
4'-carboxylic acid-3-α,α,α-trifluorocomethylphenyl ester was obtained.

Yield 2H01f s Yield 51chi, C-Sm point 68.6
°C, Sm-I point was 76.1 °C.

Examples 2 to 4 In place of 4-pentylbiphenyl-4'-carboxylic acid chloride in Example 1, 0.01 mol of the corresponding carboxylic acid chloride was used to carry out the operation according to Example 1. The compound was obtained. The results are shown in Example 1.
It is also shown in Table 1.

Table 1 Example 6 (Usage example) The N-I point 1 of the liquid crystal mixture is 44°C and the viscosity is 2.
The 40 cps dielectric anisotropy at 0°C was +12.4. When it is used in a twisted nematic cell, the threshold voltage is 1.65 V and the saturation voltage is 2.31 V.
It is.

All 90 doses of this liquid crystal mixture were added to 10 parts of trans-4-(trans-4-hephthylonclohexanecarboxylic acid-3-α,α,α-triple orophenyl ester) of Example 3 of the present invention. N- of the liquid crystal mixture with added
The I point rose to 46°C, the dielectric anisotropy was +11.2, and the viscosity was 39 cp at 20°C. Also, Twisted
When used as a nematic cell, the threshold voltage is 1°60V.
, the saturation voltage was slightly lower at 2.30V.

that's all

Claims (1)

[Claims] (1) General formula (in the above formula, R represents a hydrogen atom, an alkyl group having 1 to 15 carbon atoms, or an alkoxy group, represented by 3-α, α, α
- Ester derivatives having a trifluoromethylphenol group. (3-α, α, α
- A liquid crystal composition containing at least one ester derivative having a trifluoromethylphenol group.