JPS5872527A - 1,4-disubstituted benzene - Google Patents

Abstract

NEW MATERIAL:The 1,4-disubstituted benzene of formulaI(R is 1-10C alkyl or alkoxy; the group of formula II is group of formula III, formula IV or formula V). EXAMPLE:1-(trans-4'-Cyclohexylcyclohexyl)-4-methoxybenzene. USE:A component of a liquid crystal composition. It is a smectic liquid crystal having low viscosity, and is suitable especially for improving the viscosity of the composition. The compound of formulaIwherein the group of formula II is formula III or formula V is especially stable to moisture, air, heat, light, etc. PROCESS:The compound of formulaIwherein the group of formula II is formula IV can be prepared by (1) reacting the 4-substituted bromobenzene of formula VI with metallic magnesium, (2) reacting the resultant compound of formula VII with 4-cyclohexylcyclohexanone of formula VIII to obtain the compound of formula IX, and (3) dehydrating the product using KHSO4 as a catalyst. Reduction of the product with Raney-nickel catalyst affords another compound of formulaIwherein the group of formula II is formula III.

Description

[Detailed description of the invention] The present invention relates to a new low-viscosity liquid crystal material.

Liquid crystal display elements utilize the optical anisotropy and dielectric anisotropy of liquid crystal materials, but depending on the display format, T
N type (twisted nematic type)%DS type (dynamic scattering type),
There are various types such as guest/host type and tDAP type, and the properties of liquid crystal materials suitable for each type of use are different. However, it is common for all liquid crystal materials to be stable to moisture, air, heat, and light. The optimal dielectric anisotropy value (, Δε
). However, at present, there is no single compound that satisfies these conditions, and the current situation is to use liquid crystal compositions obtained by mixing several types of liquid crystal compounds and non-liquid crystal compounds.

Recently, especially from low temperature (about -20℃) to high temperature (80 to 90℃)
Since there is an increasing demand for display elements that can operate over a temperature range of about 10.degree. C., there is a need for liquid crystal compositions that have excellent operating characteristics over a wider temperature range.

An object of the present invention is to provide a novel liquid crystal compound useful as a component of such a liquid crystal composition, particularly suitable for improving viscosity.

That is, the present invention provides 1,4- represented by the general formula (1) (in the above formula, R represents an alkoxy group having 1 to 10 carbon atoms, and XΣt represents -0-1U or minutes). It is a di-substituted benzene.

The compounds of the present invention mainly exhibit smectic liquid crystals, have low viscosity, and are particularly stable against moisture, air, heat, light, etc., especially those where -()- is -0- and -C=-.

Next, the method for producing the compound of the present invention is shown in which 4-substituted bromobenzene is reacted with metallic magnesium, and 4-
1-(1'
-hydroxy-4'-cyclohexylcyclohexyl)
-4-substituted benzene. This was then dehydrated using potassium hydrogen sulfate as a catalyst to produce 1-(4'-cyclohexylcyclohexen-1'-yl)-4-substituted benzene.

When this product is further reduced to normal pressure of 50°C using a Raney nickel catalyst in a mixed solvent of ethanol and n-hebutane, 1
- (4'-cyclohexylcyclohexyl)-4=substituted benzene is obtained. Since this is a mixture of trans and cis isomers, it is recrystallized from ethanol to obtain the desired 1-(
trans-4'-cyclohexylcyclohexyl)-4
-Substituted benzene was produced. (If oxidized with chloro2nyl instead of reducing 11, 4'-cyclohexyl-
4-substituted biphenyl (1) is obtained.

The above is expressed by a chemical formula. Hereinafter, the manufacturing method and usage examples of the compound of the present invention will be explained in more detail using Examples.

Example 1 (1-(4'-cyclohexylcyclohexane-1'-
[Preparation of 4-methoxybenzene] Three pieces of 3,6 t (0,149 mol) of magnesium turnings were placed in a flask, and 4-bromoanisole 2'/, 9 f (0
, 149 mol) in tetrahydro7rane 5
0-, keeping the reaction temperature at 30-35°C in a nitrogen stream,
If the solution is slowly added dropwise without stirring, the reaction will occur and the magnesium will dissolve in 3 hours to uniformly produce 4-methoxy-7enylmagnesium bromide. To this, 21,3 t (0,118 mol) of cyclohexylcyclohexanone dissolved in tetrahydro7rane to give 50d was added dropwise as quickly as possible while maintaining the reaction temperature at 5 to 10°C.

After the dropwise addition, the temperature was raised to 35°C and stirred for 30 minutes, and then 50° of 3N hydrochloric acid was added. The reaction solution was taken into a separator and extracted 3 times with 300-g of n-hebutane. The remaining oil is 1-(1'-hydroxy-4'-cyclohexylcyclohexyl)-4-
It is methoxybenzene. Add to this 6 tons of potassium hydrogen sulfate.
and dehydrated at 160°C for 2 hours in nitrogen gas and sulfur. After cooling 2
After adding 00- toluene, potassium hydrogen sulfate is separated by P, and the toluene layer is washed with water until the washing solution becomes neutral. Next, toluene was distilled off under reduced pressure, and the remaining oil was recrystallized from ethanol to obtain 1-(4'-cyclohexylcyclohexen-1'-yl)-4-methoxybenzene. The m and p of this are 115.8 to l l 6.8
It was ℃.

Yield 16f1 Yield 50%.

Examples 2-5 Preparation of 1-(4'-cyclohexylcyclohexen-1'-yl)-4-substituted benzenes in a similar manner using l-substituted promobenzene in place of 4-bromoanisole in Example 1 did.

These results are shown in Table 1 together with the results of Example 1.

Table 1 Example 6 (Production of 1-(trans-4'-cyclohexylcyclohexyl)-4-methoxybenzene) l-(4'-cyclohexylcyclohexene-1'- produced in Example 1)
Il)-4-) dtCybenzene 16F catalytic reduction was carried out at normal pressure at 50° C. by dissolving in ethanol zoosgK together with 5 tons of nickel catalyst and absorbing 500 mg of hydrogen.

The catalyst is separated from P and it is recrystallized. Since the obtained product is a mixture of cis and trans isomers, the recrystallization is repeated again with ethanol to isolate the trans isomer. This is,
1-() lance-4'-cyclohexylcyclohexyl)-4-methoxybenzene. This one is m, p
92.8°C, yield 51. The yield was 3196.

Examples 7 to 10 In the same manner as in Example 6, L*1-(
4/-cyclohexylcyclohexen-1'-yl)-
Using 4-substituted benzene 16f, the same operation was carried out using 200 wj of ethanol as the solvent and 200 wj of ethanol.
1-(trans-4'-cyclohexylcyclohexyl)-4- using a mixed solvent of - and n-heptane 50-
[Converted benzene was produced. The yield, physical properties, etc. of the obtained product are shown in Table 2 together with the results of Example 6.

Table 2 Example 11 [Production of 4'-cyclohexyl-4-methoxybiphenyl] 1' 7j 1- (4'-Cyclohexylcyclohexen-1'-yl)-4-methoxybenzene 5f produced in Example 1 was added to xylene. The mixture is reacted with chloranil 12F in 1 oosd under reflux on a heating mantle for 12 hours. After the reaction was completed, the mixture was allowed to cool, then 500 g of toluene was added thereto, and the mixture was washed with 3N hydrochloric acid. A precipitate is deposited, so after suction and filtration, the toluene layer is
Wash with N-caustic soda aqueous solution. As the precipitate is deposited again, suction is applied again. After washing with water, the toluene is distilled off and concentrated until the total concentration becomes 40-. If left to stand, crystals will precipitate and the desired 4'
-Cyclohexyl-4-methoxybiphenyl was obtained. The yield was 1.5 F, and the yield was 29. Also, the C-8 point of this product is 118.0°C, the 8m-I point is l 94,
It was 0°C.

Example 12 (Application example 1) 4-pentyl-4'-cyanobiphenyl 45-
4-Hebutyl-4'-cyanobiphenyl 29th-octyloxy-4'-cyanobiphenyl 15%
A liquid crystal mixture having a composition of 4-pentyl-4'-cyanoterphenyl 11 has an N-I point of 63.3°C and a viscosity of 48 cp at 20°C.

1-()? produced in Example 8 was added to 95 parts of this composition. N-I of a liquid crystal composition obtained by adding 5 parts of 4'-cyclohexylcyclohexyl)-4-propoxybenzene
The temperature was 61.8°C and the viscosity was 47.5 cp at 20°C.

Example 13 (Application example 2) 4-pentyl-4'-cyanobiphenyl 51%
4-Hebutyl-4'-cyanobiphenyl 32%
The N-I point of the composition 4-octyloxy-4'-cyanobiphenyl etch is 44.3°C, and the viscosity at 20°C is 4001). The N-I point of the liquid crystal composition prepared by adding 10 parts of cybenzene in 1-(trans-4'-cyclohexylcyclohexyl) methane prepared in Example 5 of the present invention to this composition 9015 has an N-I point of 44.1°C. The viscosity at 20°C was 39 cp.

that's all

Claims (1)

[Scope of Claims] 1,4-disubstituted benzene represented by the general formula (in the above formula, ``al'' having 1 to 10 carbon atoms).