JPS59175454A - Ester of fluorinated alcohol - Google Patents

Abstract

NEW MATERIAL:A compound of formula I (R is 1-15C alkyl or alkoxy; ring A and ring B are formulas II or III; n is 0-5). EXAMPLE:2, 2, 2-Trifluoroethyl trans-4-( trans-4-propylcyclohexyl)cyclohexane-carboxylate. USE:A component for liquid crystal compositions: they have low viscosity, some of them show liquid crystal phase and the others do not. The addition of the product to a liquid crystal composition lowers the viscosity and threshold voltage of the composition. Further, they show high stability to moisture, heat, light and air. PREPARATION:A carboxylic acid of formula IV is allowed to react with thionyl chloride to form its acid chloride of formula V, which is allowed to react with a trifluoromethylalkyl alcohol in the presence of pyridine to give the compound of formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel low-viscosity liquid crystal substance and a liquid crystal composition containing the same.

Display elements using liquid crystals have come to be widely used in watches, calculators, etc. This liquid crystal display element utilizes the properties of optical anisotropy and dielectric anisotropy of liquid crystal materials, and liquid crystal phases include nematic 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 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.

However, in any case, it is desirable that the liquid crystal substances used in these display elements exhibit a liquid crystal phase over as wide a range as possible in nature, but there is currently no single substance that satisfies such conditions. Currently, materials that can be put to practical use are obtained by mixing several types of liquid crystal substances or non-liquid crystal substances. In addition, these materials must of course be stable against moisture, light, heat, air, etc., and the threshold voltage and saturation voltage necessary to drive the display element must be as low as possible, and the response speed must be as low as possible. In order to speed up the process, it is desirable that the viscosity be as low as possible. By the way, in order to widen the liquid crystal temperature range toward high temperatures, it is necessary to use a liquid crystal substance with a high melting point as a component, but liquid crystal substances with a high melting point generally have a high viscosity, so the liquid crystal composition containing it also has a high viscosity. As a result, the response speed of liquid crystal display elements that can be used at high temperatures, for example, about 80° C.1, especially at low temperatures, tends to be significantly slow. The compound of the present invention is a liquid crystalline compound useful for lowering the viscosity of a liquid crystal composition by adding it as a component in such a case.

That is, the present invention relates to a carboxylic acid represented by the general formula (in the above formula, R is hydrogen or alkyl having 1 to 15 carbon atoms, -+ is - or (), respectively, and n is O to 5) and trifluoro An ester of methylalkyl alcohol and a liquid crystal composition containing the same.

The compounds of the present invention may or may not exhibit a smectic liquid crystal phase, but they all have low viscosity, and by adding this as a component to a liquid crystal composition, the viscosity of the liquid crystal composition can be lowered. . It is also possible to lower the threshold voltage. It also has good stability against moisture, heat, light, and air.

Next, a method for producing the compound of the present invention will be described. First, a carboxylic acid corresponding to the final target product is converted into an acid chloride using thionyl chloride, and then reacted with trifluoromethylalkyl alcohol corresponding to the final target product in the presence of pyridine to obtain an ester of trifluoromethylalkyl alcohol of the target carboxylic acid. .

The above is expressed as a chemical formula: (J) Hereinafter, the manufacturing method and usage examples of the compound of the present invention will be explained in more detail with reference to Examples.

Example 1 [trans-4-(trans-4-propylcyclohequinyl)cyclohexanecarboxylic acid-2,2,2-]!
Preparation of I-fluoroethyl ester] 2.52 kg of trans-4-(trans-4-propylene clohequinyl)chlorhequitincarboxylic acid is heated with 20 ml of thionyl chloride at 80°C and 1 nicorothermic temperature. The reaction solution is 2
The mixture became homogeneous within a few hours, and the reaction was continued for another 1.5 hours.

Excess thionyl chloride is distilled off under reduced pressure. The remaining oil is the acid chloride. On the other hand, add acid chloride to 212.2-trifluoroethanol dissolved in pyridine 20-, then add 100 ml of toluene,
- Set up in the evening. First, remove the toluene layer with 6N in a separatory funnel.
Wash with hydrochloric acid, then with 2N caustic soda solution and finally with water until neutral. After drying it over anhydrous sodium sulfate, the toluene layer was distilled off under reduced pressure. The remaining oil was recrystallized from ethanol to obtain the desired trans-4-(trans-
4-brobylcyclohexanecarboxylic acid-212+2-) refluoroether was produced. Yield 1 t s Yield 43%.

Its C-8 point (numerical point) is 33.3℃, S-I
The point (clearing point) was 38.7°C.

Examples 2 to 5 In the same manner as in Example 1, the trans-
The compounds of Examples 2 to 5 in Table 1 were prepared by substituting the corresponding carboxylic acid of interest for 4-()lance-4-propylcyclohexyl)cyclohexanecarboxylic acid. Their physical property values are shown in Table 1 along with those of Example 1.

Table 1 Example 6 (Usage example) trans-4-propyl-(4'-cyanophenyl)cyclohexane 24-trans-4-pentyl-(4'-cyanophenyl)cyclohexane 36-di-trans-4-hebutyl-(4 The N-I point of a liquid crystal composition having the following composition: 25% cyclohexyl ('-cyanophenyl) 15% 4-anor 4'-() lance-4-pentylcyclohexynyl)piphenyl. When this liquid crystal composition was sealed in a TN cell (twisted nematic cell) with a cell thickness of 10 μm, the operating threshold voltage was 1.83.
V, the saturation voltage was 2.53 V. Also, the viscosity is 2
It was 28 Cp at 0°C.

To 90 parts of this liquid crystal composition, 10 parts of trans-4-(trans-4-propylcyclohexyl)cyclohexanecarboxylic acid 2 + 2 + 2-trifluoroether ester prepared in Example 1 was added. -I point is at 66°C, threshold voltage is 1.50 V, saturation voltage is reduced to 2.10 V, and viscosity is 24 Cp at 20°C.
It went down to .

that's all

Claims (2)

[Claims] (1) An ester of a carboxylic acid and trifluoromethylalkyl alcohol represented by the general formula (the middle of the above formula represents hydrogen or a having 1 to 15 carbon atoms, and n is ○ to 5). (2) Contains at least one type of ester of carboxylic acid and trifluoromethylalkyl alcohol represented by the general formula (in the above formula, R represents hydrogen or a having 1 to 15 carbon atoms, and n is O to 5) A liquid crystal composition characterized by: