JPS59141539A - Ester derivative - Google Patents

Abstract

NEW MATERIAL:A compound expressed by formula I (R and R' are 1-10C alkyl). EXAMPLE:Methyl trans-4-( trans-4-methoxymethylcyclohexyl )cyclohexanecarboxylate. USE:One component in liquid crystal compositions, having a low viscosity (about 10cP at 20 deg.C) and small dielectric anisotropy value, capable of reducing the viscosity without reducing N-I point (about 30 deg.C), usable without selecting the liquid crystal system due to easy mixing with another liquid crystal, and useful as display elements. PREPARATION:A 4-(trans-4-alkoxymethylcyclohexyl)benzoic acid expressed by formula II is reduced with metallic sodium in isopropyl alcohol solvent to form a compound expressed by formula III, which is then reacted with SOCl2 to give an acid chloride expressed by formula IV. The resultant acid chloride expressed by formula IV is then reacted with an alkyl alcohol expressed by the formula R'OH in pyridine to afford the aimed compound expressed by formula I .

Description

DETAILED DESCRIPTION OF THE INVENTION Display elements using a new liquid crystal with low viscosity and a small optical anisotropy value 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 the liquid crystal phases include a nematic liquid crystal phase, a smectic liquid crystal phase, and a cholesteric liquid crystal phase. The one that utilizes this is the most widely put into practical use. That is, they include TN (twisted nematic) type and DS type (dynamic scattering type).
, guest-host type, DAP type, etc., and the properties required of the liquid crystal materials used for each type are different. but,
In any case, it is desirable that the liquid crystal materials used in these display elements exhibit a liquid crystal phase over as wide a range as possible in nature, but at present there is no single material that satisfies such conditions, and there are only a few. Currently, materials that can be put to practical use are obtained by mixing liquid crystal materials or non-liquid crystal materials. 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 must be as low as possible. In order to increase the speed, it is desirable that the viscosity be as low as possible. 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 a result, the response speed of liquid crystal display elements that can be used at high temperatures, for example, up to about 80° C., especially at low temperatures, tends to become significantly slower. However, the present inventors found a low-viscosity liquid crystal material suitable for such purposes and arrived at the present invention.

That is, the present invention provides trans-4-(trans-4-alkoxymethylcyclohexyl)cyclohexanecarboxylic acid represented by the general formula % (in the above formula, R and R' represent an alkyl group having 1 to 10 carbon atoms). An alkyl ester and a liquid crystal composition containing the same.

The compound of the present invention has a viscosity of about 10 ep at 20°C, and has an N-I point of about 80'C, so the viscosity can be lowered without significantly lowering the N-I point. Also, since it can be mixed well with other liquid crystals, it can be used regardless of the liquid crystal type. Since the optical anisotropy value is small, it can also be used for display elements that take advantage of this characteristic.

Next, a method for producing the compound of the present invention will be described.

Trans-4-(trans-4-alkoxymethylcyclohexyl)cyclohexanecarboxylic acid is obtained by reducing 4-(trans-4-alkoxymethylcyclohexyl)benzoic acid produced by a known method in an isoamyl alcohol solvent under the action of metallic sodium. shall be. By reacting this with thionyl chloride to form an acid chloride, and then reacting with an alkyl alcohol in pyridine, the desired trans-4-
(Tone-4-alkoxymethylcyclohexyl)
A cyclohexanecarboxylic acid alkyl ester is obtained.

If the above is expressed as a chemical formula, (I) (R and R' in the above formula are the same as above) The present invention will be explained in more detail with reference to Examples below.

Example 1 (Production of trans-4-():7-methoxymethylcyclohexyl)cyclohexanecarboxylic acid methyl ester] (1) trans-4-(trans-
Production of 4-methoxymethylcyclohexyl) cyclohexanecarboxylic acid 4-()trans-4-methoxymethylcyclohexyl)
10 f of benzoic acid is stirred with 2500 g J of isoamyl alcohol and heated to 90°C. When 30y of metallic sodium is added, a violent reaction begins. While continuing to reflux, an additional 120% of metallic sodium was added over 3 hours.
When g is added, the reaction solution gradually becomes homogeneous. After the reaction is complete,
Leave to cool to 100℃. Next, isoamyl alcohol is distilled off while adding water. 2000 vtl of water was added. Next, add 21 hours of 6N hydrochloric acid to make it completely acidic. The precipitate that has separated out is filtered out and washed with water. This was thoroughly dried and used in the next reaction.

(2) To 2.6y (0.01 mol) of trans-4-(trans-4-methoxymethylcyclohexyl)cyclohexanecarboxylic acid obtained in esterification (1), 10ml'c of thionyl chloride was added.
Add and warm. It becomes uniform in about 1 hour, and after further heating for about 1 hour, the excess thionyl chloride is distilled off under reduced pressure, and the remaining oil is trans-t-(trans-4-methoxymethylcyclohexyl)cyclohexanecarboxylic acid. It is a chloride. On the other hand, dissolve in 5 tttl t methanol and 10 tBt pyridine, add the acid chloride from above, stir well, and leave overnight. Toluene 20 there
0πz was added, and the toluene layer was first treated with 6N hydrochloric acid.
It is then washed successively with a 2N aqueous sodium hydroxide solution and finally with water until it becomes neutral. After drying over anhydrous sodium sulfate, the toluene was completely distilled off under reduced pressure, and the remaining crystals were recrystallized from methanol to obtain the desired trans-4-(trans-4-methoxymethylcyclohexyl)cyclohexanecarboxylic acid methyl ester. 1.5 g of crystals were obtained. Yield 56%.

Melting point: 42.6-44.6°O, N-I point: 81.6°C Example 2 (Usage example) Trans-4-propyl-(4'-cyanophenyl)cyclohexane 28% Trans-4 -Pentyl-(4'-cyanophenyl)cyclohexane 42% Trans-4-heptyl-(4'-cyanophenyl)cyclohexane 30% The N-I point of the liquid crystal composition is 52°C. The threshold voltage of this liquid crystal composition sealed in a TN cell (twisted nematic cell) with a cell thickness of 10 μm was 1.58.
V, the supply voltage was 2.12V. The viscosity was 28 cp at 20°C, and the optical anisotropy value was 0.12.

To 90 parts of this liquid crystal composition was added the transformer produced in Example 1.
4-(trans-4-methoxymethylcyclohexyl)
The N-1 point of the liquid crystal composition containing 10 parts of cyclohexanecarboxylic acid methyl ester is 49°C. The threshold voltage measured in the same manner as above was 1.51 V, and the saturation voltage was 2.10 Vf. Also, the viscosity is 20'cte 20cp
.

The optical anisotropy value was 0.10.

that's all

Claims (2)

[Claims] (1) Trans-4-():7ance-4-alkoxymethylcyclohexyl)cyclohexane represented by the general formula (in the above formula, R and R' represent an alkyl group having 1 to 1° of carbon atoms) Carboxylic acid alkyl ester. (2) Alkyl trans-4-(trans-4-alkoxymethylcyclohexyl)cyclohexanecarboxylate represented by the general formula ' (in the above formula, R and R' represent an alkyl group having 1 to 10 carbon atoms) A liquid crystal composition containing at least one type of ester. The present invention relates to liquid crystal substances and liquid crystal compositions containing the same.