JPH0257533B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel colorless liquid crystal compound and a liquid crystal composition containing this liquid crystal compound as one component. There has been a demand for liquid crystal compounds that have a wide liquid crystal temperature range and low viscosity. Liquid crystal compositions in practical use are mixtures of several types of liquid crystal compounds. Each liquid crystal compound has its own characteristics (for example, a liquid crystal compound effective in reducing viscosity, a liquid crystal compound effective in improving viewing angle characteristics, etc.) to create a composition that satisfies the required performance. Among them, as liquid crystal compounds, for example, It has been known. This is used for the purpose of increasing the upper limit of the liquid crystal temperature range (the temperature at which the phase changes from a nematic phase to an isotropic liquid) in order to expand the liquid crystal temperature range of the liquid crystal composition. As a single item, for example, , and has a wide liquid crystal temperature range. However, although a liquid crystal composition containing this liquid crystal compound has a wide liquid crystal temperature range including room temperature, the viscosity tends to increase, which is not desirable. Therefore, the present inventors considered the molecular structure, liquid crystal temperature range, and viscosity of the liquid crystal compound having the above general formula. In the liquid crystal compound of the above general formula, two ester groups are directly bonded to three benzene rings, and the polarization effect by oxygen atoms is large, resulting in high viscosity. However, due to this polarization effect, there is a size where intermolecular interactions tend to become liquid crystal, so we thought that it might exhibit a liquid crystal phase over a wide temperature range. Based on these facts, we investigated a compound having a structure containing an ether group at the end, which is effective for reducing viscosity by reducing the number of ester groups that have a large polarization effect, and arrived at the present invention. An object of the present invention is to provide a liquid crystal compound and a liquid crystal composition that have a wide operating temperature range and excellent responsiveness. The liquid crystal compound of the present invention is colorless, has a wide liquid crystal temperature range (hereinafter abbreviated as MR), and has low viscosity.

[expression] or

[Formula] is shown. ) is a compound represented by The liquid crystal compound of the present invention also has excellent chemical stability. The liquid crystal composition of the present invention is characterized in that it contains this liquid crystal compound as one of its constituent components. The liquid crystal compound of the present invention can be blended with any type of liquid crystal compound and can be applied to all liquid crystal display methods. An example of a synthetic route for the liquid crystal compound represented by the above general formula will be explained next. First, X ² -X ¹ -COOH is reduced to alcohol X ² -X ¹ -CH ₂ OH. Next, it is etherified to form X ² -X ¹ -CH ₂ OR ¹ , and then acetylated to form CH ₃ OC-X ² -X ¹ -CH ₂ OR ¹ .
Hydrolyze this to HOOC―X ² ―X ¹ ―CH ₂ OR ¹
and then halogenated the acid halide ClOC
-X ² -X ¹ -CH ₂ OR ¹ is obtained. When this acid halide is reacted with HO-X-R ² to perform an esterification reaction, the desired product is obtained. is obtained. Examples of the present invention will be described below. Example 1 30.5g of lithium aluminum hydride in a flask
Add 200ml of tetrahydrofuran and suspend. to this

[Formula] 133 g of tetrahydrofuran solution 1 was added dropwise with stirring under ice cooling, and after the dropwise addition was completed, stirring was further continued at room temperature for 2 hours. Then, when the solvent is distilled off,

[Formula] is obtained. this

[Formula] 123g was dissolved in 700g of methyl iodide and 1.5g of dimethyl sulfoxide, and after stirring at 60℃ for 2 hours, the reaction solution was poured into dilute alkali and the solvent was distilled off.

[Formula] is obtained. 51.8 g of acetyl chloride and 117 g of anhydrous aluminum chloride are placed in another flask and cooled on ice while stirring. next

[Formula] 89g was added dropwise little by little, and stirring was continued for 4 hours under ice cooling. Pour the reaction solution into dilute hydrochloric acid 1, distill off acetyl chloride, and then distill under reduced pressure to obtain is obtained. Prepare another flask and add sodium hypobromite and this Mix and stir with 50g I got it. Then this Add 100g of thionyl chloride to 30g under ice cooling,
After stirring for 4 hours

[Formula] is obtained It will be done. Furthermore,

Add 10 g of pyridine to 30 g of benzene solution (content: about 30%) of [Formula], and add the above-obtained

Add 8g of [Formula] dropwise. Thereafter, the mixture was refluxed for 2 hours, washed with water, ethyl ether was distilled off, and the residue was recrystallized from hexane and ethanol to obtain the desired product. The infrared absorption spectrum of the compound obtained here is shown in the drawing. As is clear from the figure, ester absorption appears at 1750 cm ^-1 and ether absorption appears at 1100 cm ^-1 . Furthermore, in the mass spectrum, a molecular ion peak appears at m/e366. Based on these two facts and the relationship with the raw material compounds, the compound synthesized here is 4-n-methoxymethyl-
4″ (propylphenyl) 4′-cyclohexyl phenyl carboxylate It was confirmed that Incidentally, the phase transition temperature of this compound was 103 to 166°C. The compounds shown below can also be synthesized in a similar manner. (1) 4-n-methoxymethyl-4'' (butylphenyl) 4'-cyclohexylphenyl carboxylate. (2) 4-n-methoxymethyl-4'' (pentylphenyl) 4'-cyclohexylphenyl carboxylate. (3) 4-n-methoxymethyl-4″ (heptyl phenyl) 4′-cyclohexylphenyl carboxylate. (4) 4-n-methoxymethyl-4″ (octyl phenyl) 4′-cyclohexylphenyl carboxylate. (5) 4-n-ethoxymethyl-4″ (propylphenyl) 4′-cyclohexylphenyl carboxylate. (6) 4-n-ethoxymethyl-4″ (butylphenyl) 4′-cyclohexylphenyl carboxylate. (7) 4-n-ethoxymethyl-4″ (pentylphenyl) 4′-cyclohexylphenyl carboxylate. (8) 4-n-ethoxymethyl-4″ (heptyl phenyl) 4′-cyclohexylphenyl carboxylate. (9) 4-n-ethoxymethyl-4″ (octylphenyl) 4′-cyclohexyl phenylcarboxylate. (10) 4-n-propoxymethyl-4″ (propylphenyl) 4′-cyclohexyl phenylcarboxylate rate. (11) 4-n-propoxymethyl-4″ (butylphenyl) 4′-cyclohexylphenyl carboxylate. (12) 4-n-propoxymethyl-4″ (bentylphenyl) 4′-cyclohexylphenyl carboxylate. (13) 4-n-propoxymethyl-4'' (heptyl phenyl) 4'-cyclohexylphenyl carboxylate. (14) 4-n-propoxymethyl-4'' (octylphenyl) 4'-cyclohexylphenyl carboxylate. Thereafter, other compounds can be synthesized in the same manner within the range shown by the above general formula. For example, etc. are synthesized. Incidentally, the phase transition temperature of this compound was 111 to 142°C. Example 2 Liquid crystal compound synthesized in Example 1 above (hereinafter referred to as the example compound) is an existing liquid crystal compound, e.g.

【formula】

【formula】

[Formula] 50:30:20 weight amount%), B(

【formula】

【formula】

【formula】

34:34:20:12% by weight) and the liquid crystal temperature range and viscosity were measured. The results are shown in the table. As is clear from the results, the viscosity of the liquid crystal composition according to this example increases only by 4 cp compared to A and B, and the upper limit of the liquid crystal temperature range can be raised by about 10 to 32°C.

【table】

[Table] As is clear from the above explanation, the present invention has the effect of significantly increasing the upper limit of MR without increasing the viscosity.

[Brief explanation of the drawing]

The figure is an infrared absorption spectrum diagram of a liquid crystal compound according to an example of the present invention.

Claims (1)

[Claims] 1. General formula A liquid crystal compound represented by the formula (wherein, X represents [formula] or [formula]).