GB2059949A - ip-cyanobenzoic acid-trans-4- substituted-cyclohexyl esters - Google Patents
ip-cyanobenzoic acid-trans-4- substituted-cyclohexyl esters Download PDFInfo
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- GB2059949A GB2059949A GB8024447A GB8024447A GB2059949A GB 2059949 A GB2059949 A GB 2059949A GB 8024447 A GB8024447 A GB 8024447A GB 8024447 A GB8024447 A GB 8024447A GB 2059949 A GB2059949 A GB 2059949A
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- United Kingdom
- Prior art keywords
- trans
- liquid crystal
- ester
- cyanobenzoic acid
- substituted
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C255/00—Carboxylic acid nitriles
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/17—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrogenation of carbon-to-carbon double or triple bonds
- C07C29/19—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrogenation of carbon-to-carbon double or triple bonds in six-membered aromatic rings
- C07C29/20—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring by hydrogenation of carbon-to-carbon double or triple bonds in six-membered aromatic rings in a non-condensed rings substituted with hydroxy groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/88—Separation; Purification; Use of additives, e.g. for stabilisation by treatment giving rise to a chemical modification of at least one compound
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- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K19/00—Liquid crystal materials
- C09K19/04—Liquid crystal materials characterised by the chemical structure of the liquid crystal components, e.g. by a specific unit
- C09K19/06—Non-steroidal liquid crystal compounds
- C09K19/08—Non-steroidal liquid crystal compounds containing at least two non-condensed rings
- C09K19/30—Non-steroidal liquid crystal compounds containing at least two non-condensed rings containing saturated or unsaturated non-aromatic rings, e.g. cyclohexane rings
- C09K19/3001—Cyclohexane rings
- C09K19/3066—Cyclohexane rings in which the rings are linked by a chain containing carbon and oxygen atoms, e.g. esters or ethers
- C09K19/3068—Cyclohexane rings in which the rings are linked by a chain containing carbon and oxygen atoms, e.g. esters or ethers chain containing -COO- or -OCO- groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
- C07B2200/00—Indexing scheme relating to specific properties of organic compounds
- C07B2200/09—Geometrical isomers
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C2601/00—Systems containing only non-condensed rings
- C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
- C07C2601/14—The ring being saturated
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Crystallography & Structural Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Liquid Crystal Substances (AREA)
Abstract
p-cyanobenzoic acid-trans-4- substituted-cyclohexyl esters expressed by the general formula <IMAGE> (wherein R represents an alkyl or alkoxy group of 1 to 10 carbon atoms) are new liquid crystal compounds having a positive dielectric anisotropy and are suitable for use as a component of liquid crystal compositions.
Description
SPECIFICATION
P-Cyanobenzoic acid-trans-4-substituted-cyclohexyl esters
This invention relates to novel liquid crystal compounds having a positive dielectric anisotropy and to liquid crystal compositions containing them.
Nematic liquid crystals with a positive dielectric anisotropy have been utilized as twisted nematic mode display elements or liquid crystal display elements utilizing the guest host effect. For the liquid crystals employed in such display elements, stabilities against moisture, air, light, heat, etc, have been required, and also it has been desired that the liquid crystals exhibit their liquid crystal state within as broad a temperature range as possible extending over lower temperatures to high temperatures, not to mention room temperature. However, single compounds satisfying these requirements have not been found to date, and it is the present state of the art that the object has been achieved by mixed compositions consisting of combination of compounds of different kinds.On the other hand, for display elements which utilize liquid crystal compositions, a higher display rate has been required. In order to obtain such a higher rate, it is desirable to employ compounds having a lower viscosity, but, of the liquid crystal compounds having a positive dielectric anisotropy, those having the above-mentioned properties are few. Indeed, only cyanophenylcyclohexane derivatives have been known (Japanese patent application No. 23957/1978) which might fulfil the requirements. The preparation of these derivatives is considerably difficult.
The object of the present invention is to provide novel liquid crystal compounds which can to a certain extend satisfy the above requirements and which are useful as components of liquid crystal mixed compositions.
The present invention resides in:
p-Cyanobenzoic acid-trans-4-substituted-cyclohexyl esters expressed by the general formula
(wherein R represents an alkyl or alkoxy group of 1 to 10 carbon atoms),
and liquid crystal compositions containing one or more of them.
The compounds of the formula (I) of the present invention typically have a low viscosity (n25Oc) of 30 cp, and their synthesis is relatively simple. Furthermore, since they are easily miscible with other liquid crystal compounds such as those the biphenyl, ester, azoxy, cyclohexylcarboxylic acid or other groups, it is possible to use them for various fields of application. Specific examples of other liquid crystal compounds with which he present compounds can be used include the p-alkyl-p'-cyanobiphenyls and the p-methoxy-p'alkylazoxybenzenes.
As a particular instance of the favourable characteristics of the present compounds, when R in the formula (I) is C7H15, the compound has a C-N point (solid-nematic point) of 61.5 - 62.3"C, a N-l point (nematic-clear point) of 71 .3 C and a nematic temperature range of 1 0 C; the N-l point is suitable for various display apparatus.
Thep-cyanobenzoic acid-trans-4-substituted-cyclohexy esters of the present invention can be synthesized as follows:
Firstly, the trans-4-substituted-hexanols which are one of the raw materials employed herein can be prepared in the same manner as that described in Japanese Patent Application No. 131352/1978, that is, by the successive steps of reduction of an alkylphenol, acetylation, epimerization and hydrolysis.However, in the present preferred process of the invention, these steps have been simplified as is explained as follows: In the method of the Japanese Patent Application No. 131352/1978, N-methylpyrolidone is employed as solvent and sodium ethoxide is employed as catalyst, in the epimerization after the acetylation, whereas in the presently preferred process of the invention a cyclohexanol is epimerized as it is, without acetylation, and in this epimerization, diethylene glycol is employed as solvent and sodium hydroxide is employed as catalyst. The above process is expressed by the following equations:
HO oR 'a'alytlc reduction -HO-rS-R Trans-cis mixture Oiethylene glycol HaOH (wherein R represents an alkyl or alkoxy group of 1 - 10 carbon atoms).
Next, p-cyanobenzoic acid is converted to its chloride with thionyl chloride, and the trans-4-substitutedcyclohexanol corresponding to the objective product is reacted with the chloride in the presence of pyridine to give the objective compound of the formula (I). The process is expressed by the following equations:
The physical properties of the compounds of the formula (I) prepared as above are shown in Table 1.
TABLE 1
R C - N or C - I point N - I point ( C) ( C) CH3 82.0 ~ 82.4
C2H5 77.0 ~ 80.0
C3H7 86.5 ~ 87.4 59.7
C4H9 80.2 ~ 81.1 55.5 C5H11 73.6 ~ 74.4 67.4
C6H13 63.1 ~ 63.5 66.6
C7H15 61.5 ~ 62.3 71.3
The preparation method and uses of the compounds of the present invention will be described below in more detail way of Examples.
Examples 1-7 (i) Preparation of trans-4-substituted cyclohexanols: p-Substituted phenols are hydrogenated in an autoclave with Raney nickel in the presence of ethanol as solvent and a small amount of sodium ethoxide under conditions of 150"C and 80 kg/cm2 to give trans-cis-mixed 4-substituted cyclohexanols. The 4-substituted cyclohexanols thus obtain (50 g) are introduced into a flask together with 200 mt of diethylene glycol and 20 g of NaOH and they are heated.A portion of the reaction solvent is distilled off so that the temperature of the reacton solution reaches 200 to 21 00C. At that time, in case where the starting 4-substituted cyclohexanols have an alkyl group of less carbon atoms, the objective products are also distilled off together with the solvent; hence it is necessary to pay attention.
After the above-mentioned materials were heated at 200 to 210 C for 3 to 4 hours, the resulting residual oily substances are distilled under reduced pressure to give the objective trans-4-substituted cyclohexanois with a yield of 60 ~ 75%. The boiling points of the compounds having the respective alkyl group are as follows::
Trans-4-methylcyclohexanol 170- 175"C Trans-4-ethylcyclohexanol 85 ~ 90 C/10 mmHg
Trans-4-propylcyclohexanol 100 ~ 1100C/10 mmHg
Trans-4-butylcyclohexanol 110 C/3 mmHg
Trans-4-pentylcyclohexanol 1 180C/3 mmHg Trans-4-hexylcyclohexanol 1200C/3 mmHg
Trans-4-heptylcyclohexanol 122 C/3 mmHg
(ii) Preparation of p-cyanobenzoic acid-trans-4-heptylcyclohexyl ester:
p-Cyanobenzoic acid (15 g) and thiopyl chloride (50 g) are introduced into an eggplant type flak and heated to 700C on a water bath for 4 hours during which p-cyanobenzoic acid dissolves gradually. If crystals are remaining, thionyl chloride is further added and heating is continued. Next, when excessive thionyl chloride is distilled off under reduced pressure, a remaining oily substance becomes crystals, which are dissolved in dry toluene. The resulting solution is added with stirring to a solution obtained by dissolving 20 g of trans-4-heptylcyclohexanol obtained above in (i) in 50 mb of pyridine. The reaction temperature is in the range of 60 to 80 C. The resulting material is allowed to stand over night and poured into water to give an oily substance which is subjected to extraction with 200 mt of toluene. The resulting toluene layer is washed with 6N hydrochloric acid and then 2N sodium hydroxide solution. After water-washing till washing water becomes neutral, toluene is distilled off under reduced pressure and an oily substance remains. When this oily substance is allowed to stand, it solidifies.The resulting solid is recrystallized twice with 40 - 60 mf of methanol to give 15 g of the objective product, i.e. p-cyanobenzoic acid-trans-4-heptylcyclohexyl ester. This product had a C-N poirt of 61.5 - 62.3"C and a N-l point of 67.4"C as shown in Table 1, and the observed values of its elemental analysis also accorded well with the theoretical values of the objective product, as shown in Table 2.
In the same manner, crystals of compounds of the general formula (I) having an alkyl group of 1 - 6 carbon atoms, respectively were obtained from 15 g of p-cyanobenzoic acid and 12 - 18 g of the corresponding trans-4-alkylcyclohexanols. C-N points, N-l points, etc. of these compounds are shown in
Table 1. Further their yields, values of elemental analysis, etc. are shown in Table 2.
TABLE 2
Example Rof Amount Yield of Values of elemental
formula of compounds analysis
(I) hexanol (I) (g) Observed Calculated
used value value (9) (%) (%)
C 74.1 74.04
2 CH3 12 16 H 7.0 7.04
N 5.8 5.76
C 74.5 74.68
3 C2H5 13 7 H 7.5 7.44
N 5.6 5.44
C 75.1 75.24
4 C3H7 15 13 H 7.7 7.80
N 5.2 5.16
C 75.5 75.72
5 C4H9 16 12 H 8.1 8.12
N 5.0 4.91
C 76.3 76.22
6 C5H11 18 14 H 8.4 8.42
N 4.7 4.68
C 76.6 76.64
7 C6H13 19 14 H 8.8 8.68
N 4.5 4.47
C 77.0 77.02
1 C7Hr5 20 15 H 9.0 8.93
N 4.1 4.28
Examples 8 11
Examples of mixtures containing compounds of formula (I) are shown in Table 3.
The liquid crystal materials shown in the Table 3, per se can be actuated as liquid crystals for twisted nematic type display elements. A liquid crystal cell obtained by pouring a liquid crystal material of Example 8 into a cell (distance: 10 microns) prepared by combining transparent electrodes of tin oxide subjected to silicon oxide coating and then rubbing treatment, exhibited a threshoid voltage of 1.8 V and a saturated voltage of 2.7 V at 250C, and when a square wave of 3 V and 32 Hz was impressed to the above cell, the resulting response time was 150 msec in terms of rise time and 100 msec in terms of decay time. This liquid crystal mixture can be sufficiently employed as a display element if this element is employed in a room where temperature is controlled to a certain extent.
However, since the lower limit of the nematic temperature range of this liquid crystal is insufficient for general application fields, it is desirable to add other liquid crystal compounds thereto to prepare a liquid crystal composition, and among combinations, those with liquid crystals of p-alkyl-p'-cyanobiphenyl group and p-methoxy-p'-alkylazoxybenzene group are preferably. Examples of such combinations are Examples 9
11.
Liquid crystal materials of Examples 9 and 10 were poured into the same cell as employed in Example 8 to prepare liquid crystal cells for either of which 4.5 V multiplex drive in the range of 0 to 40"C according to 1/3 duty, 1/3 bias voltage method was possible. In this case, the rise time and decay time were 150 msec and 100 msec, respectively.
Similarly, for liquid crystal cell obtained by pouring the liquid crystal material of Example 11 into the same cell as employed in Example 8, 3 V multiplex drive in the range of 0 to 40 C according to 1/3 duty, 1/3 bias voltage method was possible. In this case, the rise time and decay time were 100 msec and 90 msec, respectively.
TABLE 3
Nematic
Example Composition temperature range p-Cyanobenzoic acid-trans-4-ethylcyclohexyl ester 40% p-Cyanobenzoic acid-trans-4-propylcyclohexyl ester 15% 8 p-Cyanobenzoic acid-trans-4-butylcyclohexyl ester 15% 10 ~ 46.5 C p-Cyanobenzoic acid-trans-4-pentylcyclohexyl ester 15% p-Cyanobenzoic acid-trans-4-heptylcyclohexyl ester 15% p-Methoxy-p'-ethylazoxybenzene 10% p-Methoxy-p'-butylazoxybenzene 10% - 10 ~ 66.5 C 9 p-Cyanobenzoic acid-trans-4-ethylcyclohexyl ester 40% p-Cyanobenzoic acid-trans-4-propylcyclohexyl ester 20% p-Cyanobenzoic acid-trans-4-butylcyclohexyl ester 20% p-Methoxybenzoic acid-p'-penthylphenyl ester 10%
Trans-4-butylcycloheanercarboxylic acid-p'-ethoxyphenyl ester 10% - 5 ~ 48.5 C 10 p-Cyanobenzoic acid-trans-4-ethylcyclohexyl ester 40% p-Cyanobenzoic acid-trans-4-butylcyclohexyl ester 20% p-Cyanobenzoic acid-trans-4-pentylcyclohexyl ester 20% p-Cyanobenzoic acid-trans-4-propylcyclohexyl ester 10% p-Cyanobenzoic acid-trans-4-butylcyclohexyl ester 20% 11 p-Cyanobenzoic acid-trans-4-heptylcyclohexyl ester 20% - 3 ~ 66 C p-Pentyl-p'-cyanobiphenyö 20% p-Heptyl-p'-cyanobiphenyl 20% p-Pentyl-p'-cyanoterphenyl 10%
Claims (7)
1. Ap-cyanobenzoic acid-trans-4-substituted-cylohexyl ester expressed by the general formula
wherein R represents an alkyl or alkoxy group of 1 to 10 carbon atoms.
2. An ester according to claim 1, wherein the group R represents an alkyl group of 3 to 7 carbon atoms.
3. p-cyanobenzoic acid-trans-heptylcyclohexyl ester.
4. A liquid crystal composition comprising as one component among other a p-cyanobenzoic acid-trans-4-substituted-cyclohexyl ester as defined in claim 1.
5. A liquid crystal composition according to claim 4, comprising as main components thereof, at least one ester as defined in claim 1 and at least one liquid crystal p-alkyl-p'-cyanobiphenyl.
6. A liquid crystal compositions according to claim 4, comprising as main componenets thereof, at least one of ester as defined in claim 1, and at least one liquid crystal p-methoxy-p'-alkylazoxybenzenes.
7. A process for preparing an ester as defined in claim 1, the process involving reacting p-cyanobenzoyl chloride with the appropriate trans-4-substituted-hexanol.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP11631481A JPS5767143A (en) | 1980-07-25 | 1981-07-24 | Nickel-major alloy for single crystal casting |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP9914679A JPS5622759A (en) | 1979-08-03 | 1979-08-03 | P-cyanobenzoic acid-trans-4-substituted cyclohexyl ester |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2059949A true GB2059949A (en) | 1981-04-29 |
| GB2059949B GB2059949B (en) | 1983-07-06 |
Family
ID=14239549
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8024447A Expired GB2059949B (en) | 1979-08-03 | 1980-07-25 | P-cyanobenzoic acid-trans-4-substituted-cyclohexyl esters |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS5622759A (en) |
| DE (1) | DE3029378C2 (en) |
| GB (1) | GB2059949B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS58191781A (en) * | 1982-04-30 | 1983-11-09 | Sharp Corp | Liquid crystal composition |
| US5888421A (en) * | 1991-03-13 | 1999-03-30 | The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom Of Great Britain And Northern Ireland | Anisotropic organic compounds |
-
1979
- 1979-08-03 JP JP9914679A patent/JPS5622759A/en active Granted
-
1980
- 1980-07-25 GB GB8024447A patent/GB2059949B/en not_active Expired
- 1980-08-01 DE DE3029378A patent/DE3029378C2/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3029378A1 (en) | 1981-02-12 |
| JPS5741461B2 (en) | 1982-09-03 |
| GB2059949B (en) | 1983-07-06 |
| JPS5622759A (en) | 1981-03-03 |
| DE3029378C2 (en) | 1982-07-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |