DE2933544A1 - Cyclohexane-carboxylic acid ester with phenyl-phenol deriv. - useful as liq. crystal compsn. - Google Patents

Abstract

Ester cpds. are of formula (I) (where R is 1-8C straight chain alkyl gps.). Mixts. of the present cpds. provides liq crystal compsns. useful at room temp. They may be used with other liq. crystals such as biphenyl and ester cpds. The esters are produced by reducing 4-n-alkylbenzoic acids, heating the prod., trans-4-n-alkylcyclohexane-1-carboxylic acids and excess thionyl chloride under reflux, distilling away excess thiony chloride under reduced pressure, distilling the residue under reduced pressure, heating the acid chloride obtd. and 2-chloro-4-phenylphenol at 80 degrees C for 30 mins, recrystallising the reaction prod. with ethanol. The yield of the prod. is about 50% of the trans-4-n-alkylcyclohexane-1-carboxylic acid.

Description

Ester compound

Description: This invention is directed to ester compounds, which are useful for liquid crystal materials. For controlling, with liquid crystal materials working display elements, there are various methods, such as the FE method, the DSM method or the method exploiting the guest-host effect. Such display elements are used, for example, in electronic desktop computers, wristwatches and digital indicating instruments used. So that the usability of the display element is guaranteed, must the liquid crystal material used is stable and its liquid crystal temperature must cover the temperature range at which the element is used.

Suitable liquid crystal materials are mostly made by combining and mixing some independent liquid crystal compounds, which have a suitable chemical structure.

The object of this invention is to provide a new compound or to provide a new group of compounds that are used as constituents of liquid crystal materials are useful.

The compounds provided according to the invention for forming this object are compounds of the general structural formula below where R stands for a linear alkyl radical. These compounds can be referred to as trans-4-n-alkyl-cyclohexane-1-carboxylic acid 2'-chloro-4'-phenylphenyl ester. These compounds are produced by reacting 2-chloro-4-phenyl-phenol with an acid chloride of trans-4-n-alkyl-cyclohexane-1-carboxylic acid and thionyl chloride. The corresponding reaction can be reproduced as follows: The compounds produced in this way have a temperature range of the liquid crystal state from 20 to 400C and mostly melt between 50 and 600C.

Among these compounds, the compound with R = C5H11 is superior Properties as it melts at 4500 and the transition temperature is 870C.

A suitable combination with some of these compounds of the invention makes it possible to provide a liquid crystal material that operates at room temperature can be used. In addition, these compounds provided according to the invention can in a mixture with other liquid crystal compounds, for example biphenyl compounds or Eszer connections.

The following is the process for producing these according to the invention Connections are given in detail.

First, by reducing 4-n-alkyl-benzoic acid, the trans-4-n-alkyl-cyclohexane-1-carboxylic acid is obtained manufactured. A rule for this reduction is, for example, in 2.Chems, 12, (1972) No. 6.

Then this carboxylic acid with excess Thionyl chloride refluxed. Thereupon excess thionyl chloride at reduced Pressure removed, and the residue distilled under reduced pressure, the corresponding acid chloride is obtained. This acid chloride is made with 2-chloro-4-phenylphenol reacted in a flask, for which purpose the mixture is heated to 80.degree. C. for 30 minutes. In connection to this reaction is recrystallized from ethanol and then the reaction mixture obtained the compounds provided according to the invention. The yield is based on on trans-4-n-alkyl-cyclohexane-1-carboxylic acid about 50%. The following is in detail the preparation of exemplary compounds indicated.

Example 1: Preparation of trans-4-n-propyl-cyclohexane-1-carboxylic acid chloride.

10 g of trans-4-n-propyl-cyclohexane-1-carboxylic acid and 20 ml of thionyl chloride are placed in a 100 ml flask and refluxed until the evolution of HCl has ended. Excess thionyl chloride is then removed under reduced pressure; then the residue at reduced Distilled pressure. formed trans-4-n-propyl-cyclo- hexane-1-carbQnuyl chloride zin a 100 ml piston. give and reacted with H2-chloro-4-phenyl-phenol, for which it is heated to 80 ° C. for 30 minutes. After cooling, the reaction mixture recrystallized from Athancl, after which ifg trans-4-n-propyl-cyclohexane-1-carboxylic acid 2'-chloro-4'-phenylphenyl ester is obtained. This compound forms white crystals with a melting point of 6100 and a clearing point of 870C. The infrared absorption spectrum of this compound is shown with FIG.

Examples 2, 3 and 4 are analogous to Example 1 according to the invention Compounds produced, with only differing instead of trans-4-n-propyl-cyclohexane-1-carboxylic acid Dialkyl homologues are used, namely trans-4-n-butyl-cyclohexane-1-carbon acid or trans-4-n-hexyl-cyclohexane-1-carboxylic acid. The compounds obtained in this way and their melting point and clearing point are given below in tabular form.

trans-4-n-propyl-cyclohexane-1-carboxylic acid chloride: boiling point 1120C / 10 mm Hg column; Yield 80; trans-4-n-propyl-cyclohexane-1-carboxylic acid 2'-chloro-4'-phenylphenyl ester Melting point 61 ° C; Clearing point 870C; Yield 70 *; For the IR spectrum, see FIG. 1.

trans-4-n-utyl-cyclohexane-1-carboxylic acid chlori: boiling point 86 bis 89 ° C / 1 mm Hg column; Yield 75%; trans-4-n-butyl-cyclohexane-1-carboxylic acid-2'-chloro-4 ' -phenylphenyl ester: Melting point 590C; Clearing point 81,500; yield 75%; For the IR spectrum, see FIG. 2.

trans-4-n-amyl-cyclohexane-1-carboxylic acid chloride: boiling point 82 bis 860C / 0.5 mm Hg column; Yield 83%; trans-4-n-amyl-cyclohexane-1-carboxylic acid 2'-chloro-4'-phenylphenyl ester Melting point 480C; Clearing point 870C; Yield 74%; For the IR spectrum, see FIG. 3.

trans-4-n-hexyl-cyclohexane-1-carboxylic acid chloride: boiling point 103 up to 106 ° C / 0.5 mm Hg column; Yield 81; trans-4-n-hexyl-cyclohexane-1-carboxylic acid-2'-chloro-4 ' phenylphenyl ester: melting point 48 ° C; Clearing point 77.50C; Yield 78%; IR spectrum see Fig. 4.

Note: The yields relate to what is used 2-chloro-4-phenylphenol.

Example 5: From the following components in the specified proportions (Wt. ° A) a liquid crystal material is produced.

4-n-Butyl-benzoic acid-4'-cyanophenyl ester 10% by weight of 4-n-amyl-benzoic acid-4 ' -cyanophenyl ester 14% by weight 4-n-heptyl-benzoic acid 4'-cyanophenyl ester 22% by weight » 4-n-Octyl-benzoic acid 4'-cyanophenyl ester 24% by weight of 4-n-amyl-benzoic acid 4'-n-hexyl-oxyphenyl ester 10% by weight of 4-n-hexyl-oxybenzoic acid 4-n-heptylphenyl ester, 10% by weight of 4-n-amyl-cyclohexane-1-carboxylic acid 2'-chloro-4'-phenylphenyl ester 10 wt .- * This liquid crystal material has for the clearing point or

° the transition point a temperature of 59 ° C. The voltage-dependent Permeability of this liquid crystal material in a conventional liquid crystal cell at 200C is shown in FIG. If this cell is powered by alternating current of 3V and 32 Hz are controlled at 200C, the setting time is 325 msec and the stop time 190 msec.

Claims (2)

Ester compound Patent claims: 1. Ester compound of the following general structural formula where R is a linear C1 to C8 alkyl radical. 2. Use of an ester compound according to claim 1 as a component of liquid crystal materials for liquid crystal displays.