JPS5980635A - Novel nematic liquid crystal composition - Google Patents

Abstract

NEW MATERIAL:The compound of formula I [R is 1-9C straight-chain alkyl; the configuration of two cyclohexane rings is trans (equatrial-equatrial)]. USE:A component of a liquid crystal composition. It has positive dielectric anisotropy and high compatibility. The viscosity increase can be suppressed to remarkably low level in the preparation of a mixture having an N-I point of >=65 deg.C, and the composition is useful as a raw material of dynamic light-scattering display cell or field-effect display cell. PROCESS:The compound of formula I can be prepared by (1) reacting the compound of formula II with acetyl chloride, (2) reacting the resultant compound of formula III with an NaOH solution of e.g. NaClO to obtain the compound of formula IV, (3) reducing the compound with hydrogen, and acidifying and thermally rearranging to obtain the compound of formula V, (4) converting the compound to the halide of formula VI with a halogenation agent, and finally (5) reacting the halide with p-fluorophenol in the presence of pyridine, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to novel nematic liquid crystal compounds of 4-fluorophenol derivatives useful as electro-optic display materials.

The novel nematic liquid crystal compound provided by the present invention has the general formula () where 1t is a chain alkyl A with 1 to 90 carbon atoms! 8
, and the configurations U of the two cyclohexane rings are each in the trans (ecatria-ecatrianoto) configuration.

M-Shirt is a typical liquid crystal display cell) (M@
5chadt) etc. [APPLIED P)lYsIc
8 LETTEI781B127~12B (1971
)] proposed a market-based cell (field,
effect, mode, cell) or G, H Beilmeyer (G@HHei1mei@r) etc. [PROCE
EDING OF THIE I, E, E, E,
561162-1171 (1968))
Mode Cell) or G-1H Beilmeyer (G
IIHHe11m5ier) etc. [APPLIED P
HYSIC8LETTER813, 91 (196B))
Or D.L.White
etc. [JOURNAL OF APPLIED P)IY
There is a guest-host type cell proposed by SIC 845, 4718 (1974).

The liquid crystal materials used in these liquid crystal cells are required to be custom-made in various ways, and having a nematic phase over a wide temperature range is an important property that is commonly required for all types of display cells. It is. Many of the practical materials with such properties are usually nematic 4 at around room temperature.
1) and a compound having a nematic phase in a temperature range higher than room temperature (a) is prepared by mixing several or more components. Many of the above-mentioned mixed liquid crystals currently in practical use have at least one temperature below 0°C.
It is required to have a nematic phase over the entire temperature range from ~+65C. 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'-[i9biphenylcyclohexane, a14''t, and benzoyloxybenzoyl]. Such as diphenyl ester, which has a crystal phase-nematic phase transition temperature (C-N point) of about 100C and a nematic phase-isotropic liquid phase transition temperature (C-N point) of about 200C.
In many cases, the compound having the N-I point can be used completely. However, when these compounds are mixed in an amount sufficient to bring the N-I point of the mixed liquid crystal to a temperature of 65C or higher, they reduce the viscosity of the resulting mixed liquid crystal, thereby decreasing the response speed. It has undesirable properties that cause it to deteriorate.

The compound of formula (I) according to the present invention is a regular compound in which this intermediary is improved. That is, when preparing a practically usable mixed liquid crystal having an N-I point of 65C or more by mixing the compound of formula (I) with one or more other nematic liquid crystal compounds, The increase in viscosity of the mixed liquid crystal can be suppressed to a much smaller extent than that of the liquid crystal compound. Furthermore, the compound of formula (I) has been disclosed by the applicant in Japanese Patent Application Laid-Open No.
4,4'-comb reverse cyclohexylcarboxylic acid phenyl ester, which was reported as an excellent nematic liquid crystal material for time-division drive in Japanese Patent Publication No. 83694, has good compatibility with these compounds. By mixing with a compound, a more depressed mixed liquid crystal can be obtained.

The compound of formula (1) according to the present invention can be produced according to the following production method.

Step 1 - A compound of formula (n) is reacted with acetyl chloride and anhydrous aluminum chloride in carbon divalent or nitrobenzene to produce a compound of formula (III).

Second step: A compound of formula (IV) is prepared by reacting the compound of formula (In) with a sodium hydroxide solution of sodium hypochlorite or sodium hypobromite in dioxane.

In the third step, the compound of the set (TV) is hydroxylated) Hydrogen reduction is performed using a reduction catalyst such as Ru-C in an IJium bath solution, acidified, and the liberated carboxylic acid is taken out. Produce the compound V).

Fourth step: A compound of formula (VI) (wherein X is a halogen atom) is produced by reacting the compound of formula (V) with a halogenating agent. In the compound of formula (VI), X is preferably a chlorine atom, and thionyl chloride may be used as the halogenating agent.

Step 5 - The compound of formula (VI) produced in Step 4 is reacted with P-fluorophenol in an inert organic bath medium such as ether, benzene, or toluene using a basic compound such as pyridine as a catalyst. The compound of formula (I) according to the present invention is prepared by

Table 1 lists the eaves transfer temperature of the compound of formula (1) prepared by deception.

Table 1 (In the table, C represents a crystalline phase, N represents a nematic phase, l represents an isotropic liquid phase, and the arrow represents a phase 4i1r8.) The compound of formula (I) according to the present invention is a weak It is a nematic liquid crystal compound with a positive dielectric anisotropy and therefore, for example, in a dynamic light scattering type display cell in the state of a mixture with a nematic liquid crystal compound having a negative or weakly positive dielectric constant. 2. This compound can be used as a material and can also be used as an advantage for field-effect display cells in the state of mixture with other nematic liquid crystal compounds with strong positive dielectric anisotropy. As such, preferred representative examples that can be mixed with the compound of formula (I) and administered to the stool are:
For example, 4, , i'-ttr-substituted benzoic acid phenyl ester, 4.4'-Okisakaki cyclohexanecarboxylic acid phenyl ester, 4.4'-if? Cyclohexanecarboxylic acid biphenyl ester, 4 (41'-Chu cyclohexane carbonyloxy)an, lW 4'-Ill phenyl ester 4 (4-substituted cyclohexyl)benzoic acid d'-
R4'15 phenyl ester, 4(4-substituted cyclohexyl)benzoic acid 4'-INN dicyclohexyl ester 4.4'-biphenyl, 4.4'-phenylcyclohexane, 4.4'-fftmterphenyl, 4.4'- Examples include biphenylcyclohexane, 2(4'-f17 substituted phenyl)5-substituted pyrimidine, and the like.

The second layer is a compound of formula (1) /461, /+62, shown in Table 1, with 80 weight percent of the parent liquid crystal (A), which is currently widely used as a nematic liquid crystal material with excellent time-division driving characteristics.
The N-I point and viscosity measured for each mixed liquid crystal consisting of 20 mf% of each of VL3 and Seat 4 are posted, and for comparison, the N-I point and viscosity determined for the base liquid crystal (A) itself are displayed.
The points and viscosity are displayed.

In addition, the parent liquid crystal (A) is 8% 8% oil amount 8% by weight 8% of vehicle volume 8N Yari duck as well as 8% by weight It consists of

Table 2 From the data listed in Table 2, it can be seen that the compound of formula (I) can raise the N-I point of the mixed liquid crystal to a practically sufficient level without significantly increasing the viscosity of the mixed liquid crystal. You will understand. The viscosity value of approximately 24 centivoise/20C is 65C or higher, which is the current average practical level.
Comparing the viscosity values of various mixed liquid crystals having the I point, the viscosity values are quite low. The ability to obtain a mixed liquid crystal with such a low viscosity is of great practical value during the compounding of formula (I).

The effects of the present invention are also clarified by the following comparative experiments. A known compound of the formula whose chemical structure is similar to the compound of formula (I) according to the present invention and which is used for the purpose of increasing the N-I point of the mixed liquid crystal is used as the base material (A). The mixture was mixed at random ratios. Similarly, one of the compounds according to the present invention, a compound of formula % (2), was mixed into the base liquid crystal (A) in various proportions. Regarding the two types of mixed liquid crystals obtained in this way, each N-
The I point and viscosity were measured. Based on these measurement results, the relationship between the NI point and the viscosity is shown in FIG. 1 of the entanglement drawing.

From these facts, it can be understood that the compound of formula (1') according to the present invention exhibits a much smaller increase in viscosity with an increase in the N-I point than typical known similar compounds.

Example: Carbon ≠; Anhydrous benium chloride 160 m / 100m
I (0,120 mol) was added at room temperature (while stirring, 7.85 g (0,100 mol) of acetyl chloride was added from A. This was cooled to 1 DC, and while stirring, the formula % formula %) was added to carbon divalent. The solution dissolved in 3ml of 5r was added to Sei-FL,
After reacting at 10 tL' for 5 hours, the mixture was returned to the room and reacted for 2 hours. After the reaction, carbon di1W was distilled off, and then added to ice water and stirred at 60C for 1 hour. After cooling, it was extracted with toluene, washed with water, dried, toluene distilled off, recrystallized with W ethanol, and purified to obtain the lower fc' (hypothecide 22.9Ji' (0, L).
1842 mol) was obtained.

This compound was dissolved in dioxane 23 omlKf8 30
Keep at ~35C. While stirring, add 150 g of 125 sodium hypochlorite, 17 um of sodium hydroxide, and 13.4.9 g of sodium hydroxide.
, a solution of 13.7 CC of water was quickly added dropwise. Dripping fk
After reacting for 2 hours at 4°C to 50°C, the reaction mixture was further heated to 80C. After the reaction is completed, the mixture is cooled and made acidic, and the precipitated crystals are filtered, washed with water, and dried.
79 (0,0682 mol) was obtained.

This compound is 85% sodium hydroxide 3.5'5I! (
0,0750 mol) 300 CCK of water was dissolved, 15 g of a catalyst of 5% Ru-C1 water and 70% was added thereto, and the mixture was reduced with 80 U and 3 atm of hydrogen. After completion of the reduction, the reaction product was filtered to remove the catalyst, the filtrate was made acidic with dilute hydrochloric acid, and the precipitate was extracted with ether, washed with water, dried, and the ether was distilled off. This was heated at 200C for 24 hours in a nitrogen stream.

The thermal transition precipitation was recrystallized from ethanol to form the following compound 13.
5& (0,0482 mol) was obtained.

This compound has 100% thionyl chloride. li' was added and the mixture was rapidly flowed for 6 hours. The reaction complex thionyl chloride was removed by distillation, and the solution was poured into a bath solution of 30 cents of static water.

This bath solution was dissolved in 50 cc of anhydrous ether at 5.40.9 (0
, 0482 mol) of P-fluorophenol and 7.6
, V was added dropwise to the bath solution with stirring at 1 DC. After the completion of the dropwise addition, the reaction was carried out at reflux temperature for 2 hours, and after the completion of the reaction, the reaction product was extracted with ether. The extract was washed with water and dried, the ether was distilled off from this solution, and the obtained reaction product was recrystallized from ethanol to obtain the following compound 1.
3.211 (0,0353 mol) was obtained.

Yield rate: 35.3% Rotation temperature 81C (C→N) 156C (N4I) Example 2 The following compound was obtained in the same manner as in Example 1 (2).

Yield rate: 36.7% Transition temperature 70CCC→N) 136U (N,!I) Example 3 The following compound was obtained in the same manner as in Example 1.

Yield rate: 34.7% Rotation 44 temperature 67U (C-+N) 148U (Nco I) Example 4 The following compound was obtained in the same manner as in Example 1 and li1.

Income car 37.2% Transition temperature 83iC (C-4N) 152C (N:I)

[Brief explanation of drawings]

Figure 1 shows the compounds obtained by adding compound /162, which is one of the compounds according to the present invention, and a known compound (a) having a structure similar to this to a currently widely used base liquid crystal (A). It is a chart showing the relationship between the NI point and viscosity of mixed liquid crystal.

Claims (1)

[Claims] general formula ) A compound represented by