JPS584746A - Nematic liquid crystal and manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a new nematic liquid crystal material for electro-optical devices for the modulation of transmitted or incident light and for the reproduction of numbers, symbols and figures, and to a method for their production. Due to its dielectric anisotropy, liquid crystals exhibit special alternating effects in the chamber and can therefore be oriented. Nematic liquid crystals with positive dielectric anisotropy are aligned parallel to the electric field, whereas those with negative dielectric anisotropy are aligned perpendicular to the electric field. In the case of some liquid crystals that exhibit positive dielectric anisotropy at low frequencies, negative dielectric anisotropy occurs above the relaxation frequency due to dielectric constant relaxation. Relaxation frequency (
The dielectric anisotropy is zero in the vicinity of the isotropic frequency (3) and it has already been proposed that it can be used in electro-optical displays by driving a ray (East German Economic Patent No. 107.561). ).

Control means of this type make it possible to change and switch only by changing the electric field strength, so that the very slow decay of dielectric information in normal operation can be significantly reduced. The previously known materials for this effect have troublesome high relaxation frequencies (in the LIH2 range), have too high melting points or are chemically and thermally unstable. Conventionally known 2-
Substituted-1,4-his[4-acylkoxy]-benzene (
East German Economic Patent No. 106.9! No. 13, No. 108
．． 732 to No. 022, No. 10B, No. 025, No. 11
No. 159,575, No. 139,592; and A, 0. Griff'in etc. 1Mol Cristo Liquid Cristo (Mol, 0rY8
t, Liq6c, 0r78j, )”, 44,
267 (197B); T, A, o Chinian (Ro
Listalographia (Kris
tal'logafya) 25”.

(4) 57B (197B)), in which the 2-substituent is very small, is likewise not suitable for the two-frequency method due to its high relaxation frequency. Therefore, substances of the h'A'tf+ class which do not have this drawback or only have it only to a small extent are constantly being investigated.

The liquid crystal compound produced by the method of the present invention is described in a new book, and its production method is not known.

2-[substituted-1, 4-bis-
[4-acyloxy]-benzenoha, 2- of the benzene ring
It has only short-chain substituents in position [East German Economic Patent No. 106.93! + No. 108.022, No. 1
No. 08.023, No. 116,752, (5) No. 133575, No. 139.592;
0. Griffin, D.L., Peltz (
Wertz), A.O., Griffey. Shunia (.ri
-6 moles of Christo Liquid
Christ (Mol, 0ryst, Liqu, C!ry
st, )″, 44°:!57 (1978); T, A, a
Rotinyan, Oh, Ront, A, P, Kovs-hik
) P, V, Aaomenes, Y
u, Yu, Dnngvila K, L
. Kristall-ogafya to 1 Kristall of Ryum-tseu 23
．． 578 (197B)'). However, these materials are not well suited for the two-frequency method. This is because its relaxation frequency is relatively high (in the range of Mu). The object of the present invention is to provide a low relaxation frequency, low melting point temperature, good chemical and thermal stability and electrical optical device,
The present invention relates to a new nematic liquid crystal particularly suitable for dual-frequency operation and a method for producing the same.

The present inventor has general formula (6) (where n is 1 to 16), RB is n, and Om H2m++ (m-3 to 14). ] pure or mixed 2-n-alkyl-1,
It has been found that 4-bis-[4-acyloxy]-benzene is very suitable for use in corresponding electro-optical devices.

The relaxation frequency of nematic liquid crystals with positive dielectric anisotropy is shifted to a significantly lower value by the addition of these substances7). The molecular weight of the 4-Si crystal has already been determined by Boarender's Kenken [J] and Boarender (Vor1 direct
), 1 Siemie Crystallography Def, 7/
l/-Suihikaitey (Ohemische Kr1
e -tall-Ographie d,er 'F'
Lassigheitθn)”, Leipzig 1924
) and new comprehensive literature [D, Demuth (Dθ+nus)
, H. Thames and H. Zaschk.
θ), ′Früsuige Crystallein Q Taberen (
Fluesige Kr1stalle in Tab
ellen] VE
B Dentscher Verlag fir Gr
It has a molecular structure that is elongated as much as possible, as shown in ``Unastoff-1ndustrie'', 2nd edition, Leipzig 1976).

Therefore, in materials of the 2-substituted-1,4-bis-[4-acyloxy]-benzene type, the small 2-W
Liquid crystal properties can only be expected in the case of substituents. It is quite surprising that the M-substituted derivatives with a long n-alkyl chain in the 2-position have liquid-crystalline properties (8) and, moreover, the relaxation frequency decreases very markedly in the mixed state.

The materials of the invention have good thermal and chemical stability and some have very low transition temperatures.

The inventor has prepared the corresponding substituted benzoic acid or cyclohexanecarboxylic acid or its reactive conductor by converting it into
By reacting n-alkyl-hydroquinone, including its phenolate form, at a temperature between 0 and 250'0, optionally in the presence of an inert organic solvent.

2-, which is very suitable for electro-optical devices, especially dual-frequency operation.
It has been found that n-alkyl-1,4-bis-[acyloxy]-benzene can suppress appetite.

The reaction conditions of the method of the invention are determined by the reactivity of the derivative used. For example, free carboxylic acids are reacted with hydroquinones and water-dissociable reagents such as dicyclohexyl(9) carbodiimide in the presence of a suitable solvent (eg, tetrahydrofuran, pyridine, dimethylformamide). A particularly advantageous reaction method is to react a substituted benzoyl chloride with a 2-alkyl-hydroquinone using an organic base (e.g. pyridine, triethylamine, quinoline, etc.) or an inorganic base (e.g. potassium hydroxide-sodium, sodium carbonate, bicarbonate) IJ react in the presence of um).

The reaction is advantageously carried out in the presence of an inert solvent.

especially diethyl and dibutyl ether, dioxane,
Benzene and toluene are suitable. The A-sized organic bases used (eg pyridine, triethylamine, Norin) can simultaneously serve as bath agents.

The reaction temperature is 0° to 250°C, in particular 100 to 140°C. The esterification reaction generally takes place at a temperature of 30°C.
It ends in minutes to 24 hours.

The present invention will be explained in more detail by the following six examples.

Example 1 Some embodiments of the present invention in the first and second k below (10) Indicates the transition temperature of metal objects.

Table 1 2-n-alkyl-1,4-bis-[4-n-alkyloxybenzoyloxy]-benzene 3 R1=R2R3K N
TOH30a5H7・127・135.
50HSO04)I, ・122-1245
・(1055)OH, OaB H mouth ・98-
100 ・(85)OH50C6H+s ・
90-91.5 ・ (77) 0) 1,0
07HI5 ・ 81-82 ・ (7
0)OH3008H+7・81-82 1
(67)OH,OO9H,?・90-91
・(64-65) ・0H50010H21
・83-855 ・(6061) ・0H50
cl IH25・81-81.5・(58)
OR50Cl2H25・89-90・(56
)02H50CsHy -150-155・1s
s-15(S) ・02H50a4H9・14B-1
51・(130-151)・05H,OO5H,・
87-89 ・120-12i, 5 ・(
11) R1,,=Rg R”K
N l0HOOH・109
-111 ・(qq-1oo) ・3 7
4 9 0HOOH, R4-86・125.5-126
・4 9 37 ano OH, 104-1n5
・ 1104 9 49 0HOOH・ 81-83 ・ 106-106
．． 5 ・511 37 0HOOH, 85-86・ 94 511 49 01 (00H, 56-59・ 107-107.5
・6 +3 57 0HOOH, 67-68・ 96.5415
49 06H, 5005H,, 77-78, 5・8B06
T(,,OO6H,3,60-61・83061(,
300, H, 5・59-61・79-79.
5 ・06H,,OO8H,,・66-C5・
7706H,500,H,,,66-68・76.5
06H, 3Q O, question, , 67-68 -
7206H,,OO,,R2,・69-71・
6906H, 500, 2H25, 62-65・67
0HOOH・58-61・64-64
．． 5 ・6 13 +6 5K O, H, 5003)1. , 56-58
・99C,H,5004H,,65-67・900
, R15005H,, 74-75 860
,H,5006H,,・59-60・790
, H, 50C, H, 5, 54-56, 75, 50, ■,
50 06H+y ・59-60 ・74
07H, 5009H, ・ 60-61 ・ 7
3.5 (12) R”-R1R3K N I
OHOOH, 5a-60・69.5 7 15 To 2107H150C
IIH25・6low 675・6Z50HO
OH・61-615・65.57 1
5 12 25 0HOOH, 6 low 67 ・ (62) 7
15 +6 55 08H,,OO,H,,51-525,97,5-98
.

0HOO4H,・57-58・91 17 0HOO5H,・68-695・8451
7 0HOO6H, 5・61-62・81.5
17 0 HOO, H, 5・52-55 ・7a517 C8H570C8H47・57-585 ・
77.508H17009H19・65-67
・77C8H570C4゜R21・59-60
・ 7408HI 70CI +1125 ・
49-515 ・7208H,,OO,□H
25・55-56 ・6950HOOI(・6
5-67 ・69-69.5゜8 17
1635 08003H, 49-51 91-91
5゜ 19 0HOO,H,・ 58-61 ・84-85゜ 19 0HOO5H,・ 64-66 ・7819 0HOO6H, 3・ 64-65 “ 7 Low 7
6.5 ・ 19 Gt (OOH ・ 53-54 ・ 73-75
．． 5゜9 +9 7 15 0HO08H,, 54-56 72.5
19 0? H790C9H1, ・60-41 ・73
0HOOH・60-61・70?
+9 To II (13) R1,,,R2R"K,
N IC9H19CH'25
・41-43 ・660,H,,OH,
64-66・6low 66.5-6 33 CIQH210SH7・60-63・92-
92.5 ・OHOH,63,S5 ・(33
-33,5) ・57 6 15 0HOH・ 59-62 ・(18-19)
-496+1i CH-31-33,5・4[],5-41・
05H116111 H 613C3H7° 46-48 ・ 51-52
．． 6 lit C4H9.54-57
・(37-38) ・OH 06H,30,H,,,48-51・(50-31)
・OHOH, 27-29・ 28 6 13 6 +! 6 15 C7H15・ 44-45 ・(
23,5)OH OHC! H・4B-49,5・(20-5-21)
・6 15 8 17 0HOH・ 52-5!1,5 ・(18)6 1
S? I? OHOH-56-56,5・(17) 6 15 10 21 06H,30,, R2,, 62-64, (15-15,
5) ・061(,5C,2H2,,45-47-(
15)06H,,OH・41-43 1(15)6
33 C7H1557 0H・45-47・60-62
・0)1 0H, 18-19・405-41.
5 ・7 15 6 14108
H,,Coo O,H,,,70-72,94-95
・0HOOOOH・ 78-79.5 ・ R17
-89.

11 17 7 150 H000
00H, 79-82, 81-84・49
6 1B OH00000H Italy 6S-65173-75・49
715, - crystalline solid state, N - nematic state S - smectic state f7M, I - isotropic liquid state (same for the second coating) Table 2 2 - n-alkyl-1,4-bis -[4-n-pentyl-cyclohexanecarbonyloxy]-benzeneOH・
5B-58, 5・99-100-57. O7 0H・59-60・79・5
1/+9 05H,, 64-65 66.5-67
・46.50H・41-45 ・58.5
・38.113 0H・46-48 ・52 ・4
4A 15 Example 2 High viscosity causes low relaxation frequency of nematic liquid crystals.

(15) Viscosity of 2-di)-octyl-1,4-bis=(4-n-octyloxybenzoyloxy]-benzene (nematic phase state model) t/'0 25 56 64 76 80ν,
/c8t 96o 167 115 72 87 In comparison, 4-n-alkyloxy-benzoic IW
The viscosity of -4-n-alkyloxyphenyl ester is 10 times smaller.

Example 5 60 moles of 2-n-octyl-1,4-bis-(4-n
-octyloxybenzoyloxy]-benzene and 40
momol's 4-n-octyloxybenzoic acid-4-(β-
Isotropic frequency f of the mixture with cyanethyl)-phenyl ester. =t/'0 20 25 33
48i'O/KH281647250 The static temperature γ point d of this mixture is 68°C. The threshold voltage in the low frequency range at room temperature is 2.5V.

Example 4 (16) A mixture according to Example 3 is used in a cell of the following structure. A thin layer of liquid crystal (layer thickness of 5-60 μm) is applied between two glass sheets with a transparent conductive layer (SnO2 or ■n203) on the inside and the distance between them is It is kept constant by sandwiching the retaining material. The device is placed between a cross of polarizing material, and under a voltage of 5 V 150 KH, the cell completely extinguishes the light, whereas at 5 V/12 KH2 it becomes transparent.

Example 5 Preparation of 2-n-butyl-bis-[4-n-hexyloxy-benzoyloxy]-benzene: 1.66 g (0.01 mol) of 2-n-butyl-hydroquinone in 50 ml of distilled pyridine. 4.81 g (0.02 mol) of 4-n-hexyloxy-benzoyl chloride are added dropwise to the dissolved solution under stirring at 0°C. Leave for 24 hours at room temperature with exclusion of moisture, then 110" for 30 minutes.
heated to 0 and after cooling 100my with 2oog of ice,
Pour into the mixture with concentrated hydrochloric acid. The precipitate (17) is filtered with suction, washed with water and a little cold ethanol and recrystallized several times with ethanol. Yield: 4
．． 15 g - 72.3% of theory. Melting point 67-68'
Nematic state at 0096.5℃.

Example 6 2-n-hexyl-1,4-bis-(4-n-heptyl-benzoyloxy)-benzene 1 to 50 toluene
．． 94 g (0.01 mob) of 2-n-hexyl-hydroquinone and 3 g of pyridine are added to a solution of 1
4.7 in 20 liters of toluene under stirring at 00°C.
79 (0.02 mol) of 4-n-hebutyl-benzoyl chloride in kI solution is added dropwise. The reaction mixture with is then heated to the boiling point and filtered after cooling. The solution was washed with 50 g each of water, 5% sodium bicarbonate solution and water, dried over sodium bicarbonate and concentrated under reduced IE. The remaining oil is dissolved in ethanol and crystallized at -15°C. The recrystallization is repeated at a temperature that keeps the melting point and clearing point constant. Yield: (18) 3.70 g - 61.9% of theory. Melting point 18-19℃
. Quiet and smooth point 40.5-41.5°0° (19) Continued from page 1 G O9F 9100 9/35 Priority claim ■ June 25, 1981 (3 ■ East Germany (DD) ■ W P C07C/231120C [Inventor] Wolfgang Weisfrogg German Democratic Republic Harley Neustadt Block 223 /” 1@Inventor
Horst KreseGerman Democratic RepublicHalle-Buschkin-Strasse18

Claims (2)

[Claims] (1) General formula %formula%) Nematic liquid crystal represented by . (1) (2) In preparing a new liquid crystal 2-n-alkyl/I/-1,4-bis-[acyloxy]-henzene for drowsy optical devices represented by the general formula %) , the corresponding substituted benzoic acid or cyclohexanecarboxylic acid or a reactive derivative thereof, in particular an acid flor(2) ide, with a suitable '1-n-alkyl-hydroquinone, including its phenolate form, from 0°O to 250°C.
The method for producing a nematic liquid crystal as described above, characterized in that the reaction is carried out at 0°C in the presence of an inert organic solvent and, if an acid chloride is used, a base.