JPS58172324A - 1,4-bis(4'-(trans-4"-alkylcyclohexyl)cyclohexene-1'-yl) benzene - Google Patents

Abstract

NEW MATERIAL:A 1,4-bis[4'-( trans-4''-alkylcyclohexyl )-cyclohexen-1'-yl]benzene shown by the formula I (R is H or 1-10C alkyl). USE:A liquid crystal substance. Showing liquid crystal phase in a wide temperature range, having low viscosity. PROCESS:p-Phenyldimagnesium bromide obtained from p-dibromobenzene and metallic magnesium is reacted with 4-(trans-4'-alkylcylohexyl)cyclohexanone, to give a 1,4-bis[4'-(trans-4''-alkylcyclohexyl)cyclohexanon-1'-ol]benzene, shown by the formula II which is dehydrated in the presence of potassium hydrogensulfate as a catalyst, to give a compound shown by the formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel liquid crystal substances that exhibit a liquid crystal phase over a wide temperature range and have low viscosity, and compositions containing them.

Liquid crystal display elements utilize the optical anisotropy and dielectric anisotropy of liquid crystal materials, and there are various display methods such as TN type, DS type, guest-host type, DAP type, and white-tiller type. There are several methods, and each method requires different materials for the liquid crystal material used. For example, depending on the type of display element, the liquid crystal material may have dielectric anisotropy ε.
``needs something positive'', ``needs something negative'',
Alternatively, an intermediate value may be suitable. However, in any case, the liquid crystal material used must exhibit a liquid crystal phase over as wide a temperature range as possible and be stable against moisture, heat, air, light, etc. At present, there is no single compound that satisfies all of these conditions, and the current state of affairs is to mix several types of liquid crystal compounds and non-liquid crystal compounds to obtain compounds that can withstand practical use.

Recently, there has been a demand for liquid crystal display elements that operate over a particularly wide temperature range, that is, from low temperatures to high temperatures. In order to meet these demands, a liquid crystal that exhibits a liquid crystal phase over a wider temperature range and has low viscosity is required.

The object of the present invention is to provide a compound useful as a component of such a liquid crystal.

That is, the present invention provides 1,4-bis(4'-(trans −4“−
alkylcyclohexyl)cyclohexen-1'-yl]benzene.

□::11 The compound of the present invention exhibits a smectic liquid crystal phase over a wide temperature range. For example, one of the compounds of the present invention, 1,4-bis(4'-()lans-47-propylcyclohexyl)
Cyclohexen-1'-yl]benzene exhibits a smectic liquid crystal phase over a wide temperature range, with a crystalline-smectic (C-8m) point of 98.5°C and a smectic-transparent (Sm-C) point of 300°C or higher. It is an ideal substance for creating low-viscosity nematic liquid crystal compositions with a wide temperature range by adding it. In addition, since there is a double bond, there are two cis and trans isomers [2], which makes production easy. Magnesium bromide is reacted with 4-(trans-4'-alkylcyclohexyl)cyclohexanone to form a mixture of 1.4-bis(4'-()trans-4"-alkylcyclohexyl)cyclohexan-11-ol]benzene (1 ).Next, this is dehydrated using potassium hydrogen sulfate as a catalyst to obtain the desired 1.4-bis(4'-(
) lance-4"-alkylcyclohexyl)cyclohexen-1'-yl]benzene (1) is obtained. The above is represented by the chemical formula: (1) Hereinafter, the compounds of the present invention will be explained in more detail with reference to Examples.

Example 1 (1,4-bis(4'-()lans-47-propylcyclohexyl)cyclohexen-1'-yl)
Production of benzene] 1.2 g (0,049 mol) of magnesium shavings and p-
5.6 f (0,024 mol) of dibromobenzene was dissolved in 200 ml of tetrahydrofuran (7 mL). The solution was subjected to WMF under a nitrogen stream to gently reflux.

After 7 hours the reaction is complete and produces magnesium bromide. To this, 10.9y (0,049 mol) of 4-(trans-4'-propylcyclohexyl)cyclohexanone was dissolved in 100w1 of tetrahydrofuran, and the solution was quickly added dropwise while keeping the reaction temperature below 80°C. After simple 1.
The mixture was allowed to flow for 5 hours, and then 8N hydrochloric acid was added. 5. The reaction solution was extracted with toluene (100 ss/x3), the combined toluene layer was washed with water, and the solvent was distilled off under reduced pressure. Remaining oily substance Fi
i,4-bis(4'-()lans-4''-propylcyclohexyl)cyclohexane-1'-ol]benzene, 2.5 g of potassium hydrogen sulfate was added thereto, and the mixture was heated at 200'C in a nitrogen stream for 2 hours. Dehydrate. After cooling, 3 Q
OtR/ of toluene is added, potassium hydrogen sulfate is filtered out, the toluene layer is washed with water, and the solvent is distilled off under reduced pressure. The residue was recrystallized with toluene to obtain the desired product 1.
4-bis(4'-()lance-4"-propylcyclohexyl)cyclohexen-1'-yl]benzene. Yield 0.9 fJ. C-8m point of this product is 98.5°C.
, Sm-I point was 300°C or higher.

Example 2 4-(trans-4'-propylcyclohexyl)cyclohexane in Example 1 was replaced by 4-(trans-
Using 1,4-bis(4'-pentylcyclohexyl)cyclohexanone and following the same procedure as in Example 1,
-() lance-4"-pentylcyclohexyl)cyclohexen-1'-yl)benzene was produced. The C-
The 47.7°C% S m -I point at 8 m was 300°C or higher.

Example 8 Trans-4-propyl-(4'-cyanophenyl)cyclohexane 25.5% trans-4-pentyl-(4'-cyanophenyl)cyclohexane
84.9'/.

The nematic liquid crystal temperature range of a liquid crystal composition with a composition of 25.5% trans-4-hebutyl-(4'-cyanophenyl)cyclohexane, 15.0% trans-4-pentyl-(4-cyanobia-1-enyl)cyclohexane is -6~72
．． The viscosity at 8°Cl2O°CK is 27.6 ep, the dielectric anisotropy value Δt is +11.5, the threshold voltage of the TN cell containing this is 1.69V, and the saturation voltage Fi is 2.45.
It is V.

11.4-bis(4'-(
) lance-4"-propylcyclohexyl)cyclohexen-1'-yl] The nematic temperature range of 1 part of benzene was extended from -6 to 75.0 °C, and 20 °C
The viscosity is 81ep, the dielectric anisotropy value is +10.9,
In addition, the threshold voltage of 9 TN cells sealed with this is F11.7.
1V, and the saturation voltage Fi was 2.4V.

that's all

Claims (2)

[Claims] (1) 1,4-bis(4'-() lance-4"-
alkylcyclohexyl)cyclohexen-11-yl]benzene (2) 1,4-bis(4'-() lance-4"-
1. A liquid crystal composition containing at least one type of alkylcyclohexyl)cyclohexen-1'-yl]benzene.