JPH0247981B2 - TERUSHIKUROHEKISANKARUBONSANN3 * 44JIHAROGENOFUENIRUESUTERU - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention exhibits a liquid crystal phase over a wide temperature range. This invention relates to a novel liquid crystal material using 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 the liquid crystal material, and the liquid crystal phases include a nematic liquid crystal phase, a smectic liquid crystal phase, and a cholesteric liquid crystal phase. The liquid crystal materials used for each type are the most widely used in practical use, i.e., TN (twisted nematic) type, DS (dynamic scattering type), guest-host type, DAP type, etc. The required properties 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 a result, 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, has tended 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 hydrogen or an alkyl group having 1 to 10 carbon atoms, and X and Y each represent either F or Cl.) trans-4''-alkyl-trans-octadecahydro-p -terphenyl-trans-4-carboxylic acid-3,4-dihalogenophenyl ester and a liquid crystal composition containing the same.

The compounds of the invention have a high clearing point, for example trans-4''-propyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-3-chloro-
The C-S point of 4-fluorophenyl ester is 84
℃, the S-N point is 162.4℃, the N-I point is 265.3℃, and exhibits a liquid crystal phase over a wide temperature range, and by adding it as a component of the composition, the clearing point can be lowered without increasing the viscosity of the liquid crystal composition. can be raised. Further, the dielectric anisotropy value of the compound of the present invention is about +2,
The threshold voltage and saturation voltage of the composition do not change much. It also has good stability against moisture heat, light, etc. There is also the possibility of applying the dual frequency method.

Next, a method for producing the compound of the present invention will be shown. first,
Phenylmagnesium bromide is produced from bromobenzene and metallic magnesium, and it is reacted with 4-(trans-4'-alkylcyclohexyl)cyclohexanone to produce 4'-(trans-4''-alkylcyclohexyl)cyclohexan-1-ol- Benzene () is then dehydrated using potassium hydrogen sulfate as a catalyst to form 4'-(trans-
4″-alkylcyclohexyl)cyclohexene-
1'-yl-benzene () was obtained, which was then hydrogenated using a Raney-nickel catalyst to form trans-4'-
(trans-4″-alkylcyclohexyl)cyclohexylbenzene () is obtained. This can also be obtained () directly by hydrogenation using Raney nickel. Compound () is then dissolved in iodic acid or periodic acid. By halogenating with etc., 4-[trans-4″-alkylcyclohexyl)cyclohexyl]iodobenzene ()
If this is cyanated with cuprous cyanide, 4
-[trans-4'-(trans-4''-alkylcyclohexyl)cyclohexyl]benzonitrile () is obtained. Next, this compound () is hydrolyzed in an aqueous potassium hydroxide solution-diethylene glycol system to obtain 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. Acid chloride and then reaction with 3,4-dihalogenophenol in pyridine yields the desired trans-4″-alkyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-3,4. -dihalogenophenyl ester ()
is obtained. If the above is expressed as a chemical formula, (In the above formula, R and X are the same as above.) The compounds of the present invention will be explained in more detail with reference to Examples below.

Example 1 [trans-4″-propyl-trans-octadecahydro-p-terphenyl-trans-4
-Production of carboxylic acid-3-chloro-4-fluorophenyl ester] Place 3.6 g (0.148 mol) of magnesium turnings in a three-necked flask, and add 23.2 g of bromobenzene.
(0.148 mol) in tetrahydrofuran in a _N2 atmosphere, keeping the reaction temperature at 30-35 °C.
If you slowly drop it while stirring, it will react and 3
Over time, the magnesium dissolves and becomes homogeneous, producing phenylmagnesium bromide. 4-
(trans-4'-propylcyclohexyl)cyclohexanone (26.2 g (0.118 mol)) was dissolved in tetrahydrofuran to make 50 ml, and the reaction temperature was
Drop as quickly as possible while keeping the temperature below 10℃.
After dropping, the temperature was raised to 35℃, stirred for 30 minutes, and then
Add to 100ml of 3N hydrochloric acid. The reaction solution was transferred to a separating funnel and extracted three times with 100 ml of n-heptane.
- The heptane layer is washed with water until the washings become neutral, and then the n-heptane is distilled off under reduced pressure. The remaining oil was [4'-(trans-4''-propylcyclohexyl)cyclohexane-1'-ol]benzene, and 19 g of potassium hydrogen sulfate was added to it.
Dehydrate for 2 hours at 170°C in a stream of _N2 . 200ml after cooling
of n-heptane is added, the potassium hydrogen sulfate is separated, and the n-heptane layer is washed with water using a separating funnel until the washing liquid becomes neutral. Next, n-heptane was distilled off under reduced pressure, and the remaining oil was recrystallized from n-heptane and acetone to obtain [4-(trans-4″-
propylcyclohexyl)cyclohexene-1'-
benzene. Add 7.5g of this to ethanol
Dissolve in 500ml and add 3.2g of Raney nickel catalyst.
Catalytic reduction is carried out through hydrogen at 50°C and normal pressure. Both raw materials and products are tracked by gas chromatography,
The reduction reaction was terminated when the raw materials disappeared, that is, after 8 hours. The amount of hydrogen absorbed at this time was 800 ml. After separating the catalyst, the solvent was distilled off under reduced pressure, and the remaining crystals were recrystallized from ethanol [trans-
4′-(trans-4″-propylcyclohexyl)
cyclohexyl]benzene was obtained. This 1.4 g was dissolved in 50 ml of acetic acid, and a mixture of 0.9 ml of pure water, 1.0 ml of concentrated sulfuric acid, 0.20 g of iodic acid, 0.50 g of iodine, 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 substance exhibits a liquid crystal state, with a C-S point of 119.0℃,
The SN point was 139.2°C and the NI point was 189.2°C. Add 1.2g of this to N,Z'-dimethylformamide
Dissolve in 50ml, add 0.63g of cuprous cyanide,
Add 100 ml of n-heptane that was reacted at 130℃ for 4 hours, transfer to a separating funnel, separate the liquid with 30% ammonia water, then wash with water, wash with 6N hydrochloric acid, and then wash with water until the washing liquid becomes neutral. do. The solvent was distilled off under reduced pressure and the product obtained by recrystallizing with n-heptane was 4
-[trans-4′-(trans-4″-propylcyclohexyl)cyclohexyl]benzonitrile. Yield: 0.4 g, yield is based on cyanation reaction.
The C-S point was 731°C, the SN point was 81.1°C, and the N-I 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 hydrochloric acid and 100ml of water. Filter the precipitated crystals and wash thoroughly with water. 4 obtained in this way
-[trans-4′-(trans-4″-propylcyclohexyl)cyclohexyl]benzoic acid ()3
g with 1500 ml of isoamyl alcohol and heated to 90°C. Metal sodium 10 there
When g is added, a violent reaction begins. While continuing to reflux, an additional 80 g of metallic sodium was added over 3 hours. The reaction solution gradually becomes homogeneous. After the reaction is complete, let it cool to 100°C. Isoamyl alcohol is distilled off while adding water little by little. The water is
Added 1.5. 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 1.9
g, yield 63%. This material also exhibits liquid crystallinity and its C-
The S point is approximately 170℃, the S-N point is 282℃, and the N-I point is
The temperature was 290-300°C (with decomposition).

Carboxylic acid produced in this way ()0.5
g 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. Meanwhile, add 0.5 g of 3-chloro-4-fluorophenol to pyridine.
Add the acid chloride to 20ml of the solution, then add 100ml of toluene and leave it overnight. In a separatory funnel, remove the toluene layer first with 6N hydrochloric acid, then with
Wash 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 are recrystallized from ethanol and then from acetone to obtain the desired trans-4″-propyl-trans-octadecahydro-p-terphenyl-trans-4.
-Carboxylic acid-3-chloro-fluorophenyl ester was obtained. The yield was 0.4 g, yield 28%, and the C-S point was 84°C, the S-N point was 162.4°C, and the N-I point was 265.3°C.

The following compound was obtained in a similar manner using 3,4-dichlorophenol in place of 3-chloro-4-fluorophenol.

trans-4″-propyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-3,4-dichlorophenyl ester,
C-S point is 107℃, S-N point is 123.2℃, N-I point is
268.0℃.

Example 2 (Application example) Trans-4-propyl-(4'-cyanophenyl)
Cyclohexane 28% trans-4-pentyl-(4'-cyanophenyl)
Cyclohexane 42% trans-4-heptyl-(4'-cyanophenyl)
The nematic clearing point of a liquid crystal composition containing 30% cyclohexane is 52.
It is ℃. This liquid crystal composition was made into 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 21.2V. The viscosity was 23 cp at 20°C.

Trans-4″-propyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-2-chloro-4-fluorophenyl ester 3 prepared in the example was added to 97 parts of this liquid crystal composition.
The clearing point of the nematic composition is 58°C, the threshold voltage is 1.49V, and the saturation voltage is
It was 2.09V. The viscosity was 24 cp at 20°C.

Claims (1)

[Claims] 1. General formula (In the above formula, R represents an alkyl group having 1 to 10 carbon atoms,
trans-4″-alkyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-3,4-dihalogenophenyl ester represented by .2 General formula (In the above formula, R represents an alkyl group having 1 to 10 carbon atoms,
trans-4″-alkyl-trans-octadecahydro-p-terphenyl-trans-4-carboxylic acid-3,4-dihalogenophenyl ester represented by A liquid crystal composition characterized by containing at least one type of.