JPS5927860A - Trans-4-(4'-(trans-4"-alkylcyclohexyl)phenyl) cyclohexanecarboxylic acid-3'''-cyanophenyl ester - Google Patents

Abstract

NEW MATERIAL:The compound of formula I (R is H or 1-10C alkyl). EXAMPLE:trans-4-[ 4'- ( trans-4''-Pentylchlohexyl ) phenyl ]cyclohexanecarboxylic acid-3'''-cyanophenyl ester. USE:A liquid crystal composition having positive dielectric anisotropy. It has broad and high liquid crystal temperature range for its low viscosity, and has high transparency. The stability to moisture, heat and light is also high. PROCESS:The compound of formula I can be prepared by (1) reducing the compound of formula II with metallic sodium in isoamyl alcohol, (2) converting the resultant compound of formula III to the acid chloride of formula IV with thionyl chloride, and (3) reacting the acid chloride with 3-cyanophenol in the presence of pyridine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel liquid crystal material exhibiting a liquid crystal phase over a wide temperature range and having positive dielectric anisotropy, and a liquid crystal composition containing the same.

Display elements using liquid crystals have come to be widely used in watches, trains, 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. Furthermore, there are different types of liquid crystals, such as TN (twisted nematic) type, DS (dynamic scattering type), guest-host type, and DAP type, and the properties required of the liquid crystal materials used for each type are different.

However, in any case, the liquid crystal materials used in these display elements exhibit liquid crystal phases over as wide a range as possible in nature.
However, at present there is no single substance that satisfies such conditions, and it is possible to obtain something that can be put to practical use by mixing several types of liquid crystal materials or non-liquid crystal materials. is the current situation. Of course, these substances must also be stable against moisture, light, heat, air, etc.
Furthermore, it is desirable that the threshold voltage and saturation voltage required to drive the display element be as low as possible, and that the viscosity be as low as possible in order to increase the response speed. 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 the temperature rises, the response speed of liquid crystal display elements that can be used at high temperatures, for example up to about 80 degrees Celsius, tends to become significantly slower, especially at low temperatures. However, the present inventors found a liquid crystal material with a high liquid crystal temperature range and low viscosity, and arrived at the present invention.

That is, the present invention provides trans-4-(4'-()trans+4) represented by the general formula (wherein R represents hydrogen or an alkyl group having 1 to 10 carbon atoms).
'-alkylcyclohexyl)phenylcocyclohexanecarboxylic acid-3'-cyanophenyl ester and a liquid crystal composition containing the same.

The compounds of the present invention have a high clearing point, for example, one of the compounds of the present invention, trans-4-(4'-()trans-
4'-pentylcyclohexyl)phenylcocyclohexanecarboxylic acid-3#/-cyanophenyl ester O
The -N point exhibits a liquid crystal phase over a wide temperature range of 125°C and the N-1 point is 179°C, and by adding this as a component to a liquid crystal composition, the clearing point is increased without increasing the viscosity of the liquid crystal composition. I can do it. Further, although the current visiting 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. Furthermore, the compound of the present invention has a small optical anisotropy value Δn, and can be applied to display cells that take advantage of this property.

Next, a method for producing the compound of the present invention will be described. First, 4I-(trans-4#-alkylcyclohexyl)biphenyl-4
-Trans-4-(4'-()trans-41-) by reducing carboxylic acid with sodium metal in isoamyl alcohol.
alkylcyclohexyl)phenylcocyclohexanecarboxylic acid is obtained. Next, this was converted into acid chloride with thionyl chloride, and reacted with 3-cyanophenol in the presence of pyridine to form the desired trans-c,-(4'-()trans-41-
Alkylcyclohexyl) phenylcocyclohexane carbon #, 3#-cyanophenyl ester was produced.

The above is expressed by a chemical formula: - (R is the same as above) Hereinafter, misfire 'Jll will be explained in more detail with reference to Examples.

Example 1 7f-lycyclohexyl)phenylcocyclohexanecarboxylic acid-3"'-cyanophenyl ester (1) Production of trans-4-(4'-()trans-41-pentylcyclohexyl)phenyl]cyclohexanecarboxylic acid 4' -() Lance-42-pengylcyclohexyl)
Biphenyl-4-carboxylic acid 102 is stirred with isoamyl alcohol 2500+d and heated to 90°. When metallic sodium 30F is added, a violent reaction begins. While continuing to reflux, an additional 120 f of metallic sodium was added over 3 hours, and the reaction solution gradually became homogeneous. After the reaction is completed, let it cool] and OOCK. Next, isoamyl alcohol is distilled off while adding water.

Added 2000ml of water. Next, add two portions of 6N hydrochloric acid to make it completely acidic. The deposited precipitate is washed with PM and water. Furthermore, it was recrystallized with acetic acid to obtain trans-4-(4'-)trans-41.
-pentylcyclohexyl)phenyl]cyclohexanecarboxylic acid 4.52 was obtained. This carboxylic acid also exhibits liquid crystallinity, and its a-S point is 239.1°C, and S-1J is 274.3°C (decomposition).
Met.

(2) trans-4-(4'-()trans- produced by esterification (1))
4N-pentylcyclohexyl) phe = A, '37
9 hexanecarboxylic acid 1 y thionyl chloride 30
Heat to 80°C with rattan. The reaction solution became homogeneous in 2 hours, and the reaction was continued for an additional 1.5 hours. Excess thionyl chloride is distilled off under reduced pressure. The remaining oil is filtered with acid chloride. On the other hand, 3-cyanophenol 0.5 y 't<
After adding the acid chloride to the solution dissolved in 20 ml of pyridine, 100 g of toluene was added, and the mixture was allowed to stand overnight. In a separatory funnel, remove the toluene layer first with 6N hydrochloric acid, then with 2
Wash with N hydroxide solution and finally with water until neutral. After drying it over anhydrous sodium sulfate, the toluene layer was distilled off under reduced pressure. The precipitated crystals are recrystallized with ethanol and then with acetone to obtain the desired trans-4-(4'-
() lance-4'-pentylcyclohexyl)phenyl]7chlorohexanecarvone fi1 3m-cyanophenyl ester was obtained. Yield 0.5f, yield 39%.

Its O-N point is 125. '7 to 128.1°C, and the N-1 point was 79.5°C. Further, it was confirmed by infrared absorption spectrum and NMR that this compound was the target compound.

Trans-4-(4'-(trans-4
trans-4-(4'-()trans-41-alkylcyclohexyl)phenylcocyclohexanecarboxylic acid having another alkyl group instead of I-pentylcyclohexyl)phenylcocyclohexanecarboxylic acid having another alkyl group Trans-4-(4'-()trans-41-alkylcyclohexyl)phenylcocyclohexanecarboxylic acid-3''-cyanophenyl ester can be produced.

Example 2 (use example) trans-4-propyl-(4'-cyanophenyl)cyclohexane 28thitrans-4-pentyl-(4'-cyanophenyl)cyclohexane 42% trans-4-heptyl-(4'-cyanophenyl) ) The N-1 point of a liquid crystal composition having a composition of 30% cyclohexane is 52°C. The threshold voltage of this liquid crystal composition sealed in a TN cell (twisted nematic cell) with a cell Ig of 10 μm was 1.53.
V, the saturation voltage was 2.12 V. Also, the viscosity is 20℃
The optical anisotropy value was 0.120.

To 97 parts of this liquid crystal composition was added the trans-transformer produced in Example 1.
N-1 of a liquid crystal composition to which 3 parts of 4-(4′-()lans-4#-pentylcyclohexyl)phenyl]cyclohegysancarbonrR-3”-cyanophenyl ester was added
The point is 54°C.

The threshold voltage measured in the same manner as above was 1.55V,
The saturation voltage was 2.14V. Also, the viscosity is 24 at 20℃.
The cp and optical anisotropy values were 0.120, which was almost unchanged.

that's all

Claims (1)

[Claims] (1) trans-4-(4'-()trans-4' represented by the general formula (in the above formula, R represents hydrogen or an alkyl group having 1 to 10 carbon atoms))
-alkylcyclohexyl)phenylcocyclohexanecarvone 37'/-cyanophenyl ester. (In the above formula, R represents hydrogen or an alkyl group having 1 to 10 carbon atoms) trans-4-(4'-()trans-41
A liquid crystal composition comprising at least one type of -alkylcyclohexyl)phenylcocyclohexanecarbonit-3''-cyanophenyl ester.