JPH0232271B2 - OKUTADEKAHIDOROOPPTERUFUENIRUUTORANSUU44KARUBONSANN4 **** SHIANOFUENIRUESUTERU - Google Patents

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, calculators, 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: 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.
The properties required for the liquid crystal materials used in each case 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 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 high melting point generally have a high viscosity, and therefore the liquid crystal composition containing it also has a high viscosity. As the temperature increases, the response speed of liquid crystal display elements that can be used at high temperatures, for example, up to about 80° C., particularly at low temperatures, tends to become significantly slower. 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 is based on the general formula (In the above formula, R represents an alkyl group having 1 to 5 carbon atoms) trans-4''-alkyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester and a liquid crystal composition containing the same.

The compounds of the present invention have high clearing points, such as trans-4''-propyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophyl, which is one of the compounds of the present invention. The C-S point of enyl ester is 119.0S-N point is
At 194.3°C, the N-I point exhibits a liquid crystal phase over a wide temperature range of 300°C or higher. This can be combined with other liquid crystal compounds, such as
A ring assembly (fused By adding it as a component to a liquid crystal composition consisting of a liquid crystal compound or a liquid crystal substance or a non-liquid crystal substance having a functional group such as ester, azo, azoxy, or azomethine, the clearing point can be lowered without increasing the viscosity of the liquid crystal composition. It can be raised. Further, although the dielectric anisotropy value of the compound of the present invention is about +5, it does not change the threshold voltage and saturation voltage of the composition so much. Also moisture,
It also has good stability against heat, light, etc.

Next, a method for producing the compound of the present invention will be described. First, phenylmagnesium bromide is produced from promobenzene and metallic magnesium, and it is reacted with 4-(trans-4′-alkylcyclohexyl)cyclohexanone to produce 4′-(trans-4″-alkylcyclohexyl)cyclohexane-1. -All-
Let it be benzene (). Next, this was dehydrated using potassium hydrogen sulfate as a catalyst to produce 4′-(trans-4″-
alkylcyclohexyl)cyclohexene-1′-
yl-benzene (), which is then hydrogenated using a Raney-nickel catalyst to obtain trans-4′-(trans-4″-alkylcyclohexyl)cyclohexylbenzene (), which is ().
can also be obtained directly by hydrogenation using Raney nickel. Next, the compound () is halogenated with iodic acid or periodic acid to obtain 4-[trans-4''-alkylcyclohexyl)cyclohexyl]iodobenzene (), which is then cyanated with cuprous cyanide. Ba4-
[trans-4′-(trans-4″-alkylcyclohexyl)cyclohexyl]benzonitrile () is obtained. Next, this compound () is hydrolyzed in an aqueous potassium hydroxide solution-diethylene glycol system to form 4-[trans −4′− (trans−
4″-alkylcyclohexyl)cyclohexyl]
Manufacture benzoic acid. This benzoic acid derivative is reduced with metallic sodium in isoamyl alcohol to give trans-4''-alkyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid (). This is reduced with thionyl chloride. The acid chloride and then 4-cyanophenol reacted in pyridine to form the desired trans-
4″-alkyl-trans-octadecahydro-p
-Terphenyl-trans-4-carboxylic acid-
4″-cyanophenyl ester () is obtained.
If the above is expressed as a chemical formula, (In the above formula, R ₁ is the same as above.) The compounds of the present invention will be explained in more detail with reference to Examples below.

Example 1 [Production of trans-4″-propyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester] Three mouths of 3.6 g (0.14 mol) of magnesium shavings Place 50 ml of a solution of 23.2 g (0.148 cells) of promobenzene dissolved in tetrahydrofuran in a flask.
The reaction temperature is maintained at 30 to 35°C in a N ₂ stream, and the mixture is slowly added dropwise while stirring. The reaction takes place within 3 hours, and the magnesium dissolves and becomes homogeneous, producing phenylmagnesium bromide. To this, 26.2 g (0.118 mol) of 4-(trans-4'-propylcyclohexyl)cyclohexanone dissolved in tetrahydrofuran to make 50 ml was added dropwise as quickly as possible while keeping the reaction temperature below 10°C. 35℃ after dropping
Stir for 30 minutes, then add 100ml of 3N hydrochloric acid.
Add. The reaction solution was transferred to a separating funnel and extracted three times with 100 ml of n-heptane. The combined n-heptane layer was washed with water until the washings became neutral, and then extracted with n-heptane.
Heptane is removed under reduced pressure. The remaining oil is [4′-(trans-4″-propylcyclohexyl)]
cyclohexane-1′-ol]benzene,
Add 19 g of potassium hydrogen sulfate to this and add 170 g of potassium hydrogen sulfate in a _N2 stream.
Dehydrate at ℃ for 2 hours. After cooling, 200 ml of n-heptane was added, the potassium hydrogen sulfate was separated, and the n-heptane layer was washed with water using a separating funnel until the washing liquid became neutral. Next, n-heptane is distilled off under reduced pressure, and the remaining oil is recrystallized from n-heptane and acetone to obtain [4-(trans-4″-propylcyclohexyl)cyclohexen-1′-yl]benzene. Dissolve 7.5 g of this in 500 ml of ethanol, add 3.2 g of Raney-nickel catalyst, and perform catalytic reduction through hydrogen at 50°C and normal pressure. Both the raw material and the product are traced by gas chromatography, and when the raw material disappears, i.e. The reduction reaction was terminated after 8 hours.The amount of hydrogen absorbed at this time was 800 ml.After the catalyst was separated, the solvent was distilled off under reduced pressure, and the remaining crystals were recrystallized with ethanol. −
4″-propylcyclohexyl)cyclohexyl]
I got benzene. Dissolve 1.4g of this in 50ml of acetic acid,
Pure water 0.9ml, concentrated sulfuric acid 1.0ml, iodic acid 0.20g, iodine
A mixture of 0.50 g and 0.4 ml of carbon tetrachloride was refluxed at 80°C for 5 hours. The reaction solution was cooled, the precipitated crystals were separated, and the crystals were recrystallized with n-heptane to obtain 4-[trans-4′-(trans-4″-propylcyclohexyl)cyclohexyl]iodobenzene ( ).This product shows a liquid crystal state, with a C-S point of 119.0℃, an S-N point of 139.2℃, and a N
-I point was 189.2°C. This 1.2g is N,N′−
The mixture was dissolved in 50 ml of dimethylformamide, 0.63 g of cuprous cyanide was added, and the mixture was reacted at 130°C for 4 hours. n-
Add 100ml of heptane, transfer to a separating funnel, and add 30%
Separate the solution with aqueous ammonia, then wash with water, wash with 6N hydrochloric acid, and then wash with water until the washing solution becomes neutral.
The solvent was distilled off under reduced pressure and the product obtained by recrystallizing from n-heptane was 4-[trans-4'-(trans-
4″-propylcyclohexyl)cyclohexyl]
It is benzonitrile. The yield is 0.4g, the yield is 45% for the cyanation reaction, and the C-S point is
The temperature was 73.1°C, the SN point was 81.1°C, and the NI point was 242.5°C.

4-[trans-4'-
Add 5 g of (trans-4″-propylcyclohexyl)cyclohexyl]benzonitrile to 100 ml of diethylene glycol along with a solution of 5 g of potassium hydroxide dissolved in 10 ml of water, and heat in a flask at 200°C for 7 hours. After the reaction is complete, cool to room temperature. death,
Add 50ml of 6N-HCl and 100ml of water. Filter the precipitated crystals and wash thoroughly with water. 4-[trans-4′-(trans-4″-propylcyclohexyl)cyclohexyl]benzoic acid () obtained in this way
3 g are stirred with 1500 ml of isoamyl alcohol and heated to 90°C. Sodium metal there
When 10g is added, a violent reaction begins. While continuing to reflux, add another 80 g of metallic sodium over 3 hours. After the reaction, it gradually becomes uniform.
After the reaction is complete, let it cool to 100°C. Isoamyl alcohol is distilled off while adding water little by little. Added 1.5 liters of water. Add one portion of 6N hydrochloric acid to make it completely acidic, filter out the precipitate, and wash thoroughly with water. It was recrystallized from acetic acid to obtain trans-4-propyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid (). yield
1.9g, yield 63%. This one also shows liquid crystallinity and its C
-S point is approximately 170℃, S-N point is 282℃, N-I point is
The temperature was 290-300°C (with decomposition).

Carboxylic acid () produced in this way 0.5g
is heated to 80°C with 10 ml of thionyl chloride. 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 oil that remains is the acid chloride. On the other hand, 4-
Add acid chloride to 0.5 g of cyanophenol dissolved in 20 ml of pyridine, then add toluene.
Add 100ml and leave overnight. Wash the toluene layer in a separatory funnel first with 6N 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 precipitated crystals were recrystallized from ethanol and then from acetone to obtain the desired trans-4''-propyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester. Yield 0.3g, yield 46%. Its C-N point is 119.0, S-
The N point was 194.3°C, and the N-I point was 300°C or higher.

In a similar manner, 4-[trans-4′-(trans-
4-[trans-4′-(trans-4′-alkylcyclohexyl) with another alkyl group in place of 4″-propylcyclohexyl)cyclohexanone
The following target product can be obtained in exactly the same manner using cyclohexanone.

trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester, trans-4-methyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyano Phenyl ester, trans-4″-ethyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester, trans-4″-butyl-trans-octadecahydro-p- Terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester, trans-4″-pentyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester, trans-4 ″-hexyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester, trans-4″-heptyl-trans-octadecahydro-p-terphenyl-trans-4-carvone Acid-4-cyanophenyl ester, trans-4″-octyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester, trans-4″-nonyl-trans-octa Decahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester, trans-4″-decyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester ester.

Example 2 (Application example) Trans-4-propyl-(4'-cyanophenyl)cyclohexane 28% Trans-4-pentyl-(4'-cyanophenyl)cyclohexane 42% Trans-4-heptyl-(4'-cyanophenyl)cyclohexane The nematic clearing point of a liquid crystal composition with a composition of 30% is 52
It is ℃. This liquid crystal composition was used as a TN cell with a cell thickness of 10 μm.
When sealed in a cell (twisted nematic cell), the operating threshold voltage was 1.53V and the saturation voltage was 2.12V. The viscosity was 23 cp at 20°C.

A nematic composition was prepared by adding 3 parts of trans-4''-propyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester prepared in Example to 97 parts of this liquid crystal composition. The nematic clearing point was 61°C, the threshold voltage was 1.54V, and the saturation voltage was 2.13V.
The viscosity was 25 cp at 20°C.

Claims (1)

[Claims] 1. General formula (In the above formula, R represents an alkyl group having 1 to 5 carbon atoms) trans-4''-alkyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester .2 General formula (In the above formula, R represents an alkyl group having 1 to 5 carbon atoms) trans-4''-alkyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-4-cyanophenyl ester A liquid crystal composition characterized by containing at least one type of.