JPS6033411B2 - 1-cyclohexyl-2-cyclohexyl phenylethane derivative - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel nematic liquid crystal compounds comprising ethane derivatives useful as electro-optic display materials.

The novel nematic liquid crystal compound provided by the present invention has the general formula [wherein R and R2 each independently have 1 to 1 carbon atoms]
5 represents a straight-chain alkyl group. ] 11 {
trans(equatorial-ecatorial)-4-n-alkylcyclohexyl}-121{4-trans(equatorial-ecatorial)-4'-n-alkylcyclohexyl phenyl}ethane.

M・S is a typical type of liquid crystal display cell.
chadt) etc. [APPLIED PHYSICSLE
TTERS 18 127-128 (1971)] or the field effect mode cell proposed by G. H. Heilmeier et al.
PROCEEDINGOFTTHEI. E. E. E. 56
1162-1171 (1968)] or the dynamic scattering mode cell proposed by G.H.
H Heilmejer) etc. [APPLmD PHY
SICSLETTERS I 91 (1968)] or D L White
e) etc. [JOURNAL OF APPLIED PH
YSICS 45, 4718 (1974)].

The liquid crystal materials used in these liquid crystal display cells are required to have various properties, but having a nematic phase over a wide temperature range including room temperature is an important property that is commonly required for all types of display cells. .

Most of the materials that can be used for practical purposes have such properties by mixing several or more components, usually consisting of a compound that has a nematic phase near room temperature and a compound that has a nematic phase above room temperature. prepared. Many of the above mixed liquid crystals currently in practical use are required to have a nematic phase over the entire temperature range of at least 130qC to +65qC. In order to meet such requirements, compounds having a nematic phase in a temperature range higher than room temperature include 4,4-substituted terphenyl, 4,4' monolayer biphenylcyclohexane, and 4,4'
-substituted penzoyloxybenzoic acid phenyl ester, which has a crystalline phase-nematic phase transition temperature (C1N point) of about 100°C and a nematic phase one-isotropic liquid phase transition temperature (N-1 Compounds having a point) are often used. However, these compounds have the unfavorable property of increasing the viscosity of the resulting mixed liquid crystal, thereby decreasing the response speed. The compound of formula (1) according to the present invention is a novel compound with improved properties.

That is, when preparing a practically usable mixed liquid crystal having an N-1 point of 60 or more by mixing it with one or more other nematic liquid crystal compounds, in many cases the above-mentioned known liquid crystal compounds are mixed. The compound of formula (1) has the favorable property of being able to reduce the viscosity of mixed liquid crystals, as opposed to significantly increasing the viscosity of liquid crystals. The compound of formula (1) according to the present invention can be produced, for example, according to the following production method.

First step - Compound (W) is prepared by reacting the compound of formula (0) with the compound of formula (m) and anhydrous aluminum chloride in carbon disulfide or nitrobenzene.

Second step - The compound of formula (W) produced in the first step is reacted with hydrazine and potassium hydroxide in diethylene glycol or triethylene glycol to produce a compound of formula (1).

Table 1 lists the transition temperatures of representative compounds among the compounds of formula (1) thus produced. In Table 1, 0
is crystalline phase, S is smectic phase, N is nematic phase, 1
represent isotropic liquid phases, respectively.

The compound of formula (1) according to the present invention is a nematic liquid crystal compound having weak negative dielectric constant anisotropy, and therefore, for example,
It can be used as a material for dynamic light scattering display cells in a mixture with other nematic liquid crystal compounds that have negative or weak positive dielectric anisotropy, and also has strong positive dielectric anisotropy. It can be used as a material for field effect display cells in the form of a mixture with other nematic liquid crystal compounds. As described above, preferred representative examples that can be used in combination with the compound of formula (1) include, for example, 4.4'
Monolayer benzoic acid phenyl ester, 4,4 monosubstituted cyclohexanecarboxylic acid phenyl ester, 4,4 monosubstituted cyclohexanecarboxylic acid biphenyl ester, 4(4-
Substituted cyclohexanecarbonyloxy)benzoic acid 4'-substituted phenyl ester 4(4-monosubstituted cyclohexyl)benzoic acid 4-substituted phenyl ester, 4(4-substituted cyclohexyl)benzoic acid 4'-substituted cyclohexyl ester, 4.4 -biphenyl, 4,4-phenylcyclohexane, 4,4'-monosubstituted terphenyl, 4,4-biphenylcyclohexane, 2(4'-monosubstituted phenyl)5-monosubstituted pyrimidine, and the like.

Table 2 shows the 80% by weight and
Compound No. of formula (1) shown in the table. 1.No. 2.No
．． 3 No. 4.No. et al. No. 6, No. The N-1 point and viscosity measured for each mixed liquid crystal consisting of 2% by weight of each of 7 are displayed, and for comparison, the N-1 point and viscosity measured for the base liquid crystal itself are displayed. It is.

In addition, the base liquid crystal contains 3% by weight of 4% by weight. 15% by weight as well as 15% by weight It consists of

Table 2 1 tablet weight % 1 turtle weight % 8 weight % 8 weight % 8 weight % 8 weight % 8 weight % and 8 weight % Similarly, Table 3 shows the mother fluid Salmon B} 8% by weight of compound No. 8 of formula (1) shown in Table 1. 1.No. 2.No.
3.No. 4.No. Fu No. 6, No. 2 of each of 7
N− measured for each mixed liquid crystal consisting of 0% by weight
1 point and the viscosity are displayed, and for comparison, the N-1 point and the viscosity measured for the base liquid crystal B itself are displayed.

In addition, the weight% of the mother liquid crystal housing It consists of

Table 3 From the data posted in Tables 2 and 3, the compound of formula (1) lowers the viscosity of the mixed liquid crystal and reduces the N-
You can understand that it increases the score by 1 point.

The viscosity value of approximately 20 centiboise/20 qo in Table 3 is
This value is considerably lower than the viscosity value of various mixed liquid crystals having an N-1 point of 65° C. or higher, which is at the current average practical level. The practical value of the compound of formula (1) lies in the fact that mixed liquid crystals with such low viscosity can be obtained. The effects of the present invention are also clarified by the following comparative experiments.

Known compounds of the formula whose chemical structure is similar to the compound of formula (1) according to the present invention and which are widely used for the purpose of increasing the N-1 point of the mixed liquid crystal are used in various proportions according to the above-mentioned parent liquid crystal. mixed with.

Similarly, one of the compounds according to the invention, ie the compound of formula, was mixed in various proportions with the parent liquid crystal (B).

Regarding the two types of mixed liquid crystals obtained in this way, each N
-1 point and viscosity were measured. Based on these measurement results,
FIG. 1 of the attached drawings shows the relationship between the N-1 point and the amount added, FIG. 2 shows the relationship between the viscosity and the amount added, and FIG. 3 shows the relationship between the N-1 point and the viscosity. These results, especially the results shown in Figure 3, show that when typical known similar compounds are added, the viscosity of the resulting mixed liquid crystal increases significantly as the N-1 point increases; It will be understood that when the compound of formula (1) according to the present invention is added, the viscosity of the resulting mixed liquid crystal decreases as the N-1 point increases. Next, the present invention will be specifically explained using examples.

Example 1 Anhydrous aluminum chloride 16% in 100% carbon disulfide.
0.0 mol (0.12 mol) was added thereto, and 20.3 mol (0.10 mol) of trans-4-n-propylcyclohexyl acetate chloride was added dropwise while stirring at room temperature.

Cool this to -5℃, and while holding the trans-41n
-Propyl-1-phenylcyclohexane 20.2 hours (
0.10° C.) was added dropwise, and the mixture was allowed to react at -5° C. for 5 hours, then returned to room temperature and allowed to react for 2 hours. After the reaction, carbon disulfide was removed, and the mixture was added to ice water and stirred at 60°C for 1 hour. After cooling, it was extracted with ether, washed with water, dried, and after distilling off the ether, it was purified by recrystallization with n-hexane-ethanol to obtain the following compound 28.6 (0.0777 mol). This compound contains triethylene glycol 80',
Hydrazine hydride 6.22 mol (0.124 mol)
), add 12.9 liters of potassium hydroxide (0.23 dens hol), gradually raise the temperature while worshiping, and bring it to 18,000 ml.
Allowed time to react.

After cooling, 200ml of water was added and extracted with ether. After washing with water and drying over anhydrous sodium sulfate, the ether was removed and recrystallization was carried out with n-hexane-ethanol to obtain the following compound 23.8 mol (0.0672 hol).

Yield 67.2% Transition temperature 460 (C→S)
10 units ○ (SZN) 131°C (N 1) Example 2 The following compound was obtained in the same manner as in Example 1.

Yield 65.0% Transition temperature 12600 (C→
S) 131qo (S) 134q C (N) Example 3 The following compound was obtained in the same manner as in Example 1.

Yield 59.8% Transition temperature 58qo (C→S
) 7 0 (S 0 N) 10 ○ (N 1) Example 4 The following compound was obtained in the same manner as in Example 1.

・Yield 64.2% Transition temperature 3yo (C→S
)11700(SkoN)12bi○(Nko1) Example 5 The following compound was obtained in the same manner as in Example 1.

Yield 60.8% Transition temperature 7130 (C→S
)8r0(SkoN)103q○(N21) Example 6 The following compound was obtained in the same manner as in Example 1.

Yield 61.8% Transition temperature 24qo (C→S
) 11400 (SN) 128 ○ (N 1) Example 7 The following compound was obtained in the same manner as in Example 1.

Yield 62.9% Transition temperature 23qo (C→S
) 13500 (SkoN) 13 is ○ (Nko1)

[Brief explanation of the drawing]

The drawing shows No. 1, one of the compounds according to the present invention. No. 3 is a known compound having a chemical structure similar to No. 3.
Figure 1 shows the N-1 point and the amount added, and Figure 2 shows the changes in the physical properties of the mixed liquid crystal that occur when compound No. 8 is added in various proportions to the currently widely used base liquid crystal. shows the relationship between the viscosity and the amount added, and FIG. 3 shows the relationship between the N-1 point and the viscosity. Purple'Figure 2Figure 3

Claims (1)

[Claims] 1 General formula ▲ Numerical formula, chemical formula, table, etc. ▼ [In the formula, R_1 and R_2 each independently represent a linear alkyl group having 1 to 5 carbon atoms. ] A compound represented by