Patent number: 5630962
Abstract: 2-Fluoropyridines, processes for their preparation and their use in ferroelectric liquid crystal mixturesA 2-fluoropyridine of the formula (I) ##STR1## in which the symbols have the following meaning: R.sup.1, R.sup.2, independently of one another, are, for example, H or straight-chain or branched alkyl, A.sup.1, A.sup.2, A.sup.3, A.sup.4, identical or different, are, for example, 1-phenylene, pyrazine-2,5-diyl or trans-1,4-cyclohexylene, M.sup.1, M.sup.2, M.sup.3, M.sup.4, identical or different, are, for example, --O-- or --CO--O--, R.sup.3, R.sup.4, R.sup.6, R.sup.7, independently of one another, are, for example, H or straight-chain or branched alkyl, M.sup.5 is, for example, --O--CO-- or a single bond, k, l, m, n, o, p, q, r are zero or one, with the proviso that the sum of k+m+p+r is less than 4 and greater than zero, can advantageously be used as a component in ferroelectric liquid crystal mixtures.
Type:
Grant
Filed:
May 11, 1995
Date of Patent:
May 20, 1997
Assignee:
Hoechst Aktiengesellschaft
Inventors:
Hubert Schlosser, Rainer Wingen, Gerd Illian, Claus Escher
Patent number: 5354500
Abstract: Use of optically active carboxylic esters of oxygen-containing heterocycles as doping substances in liquid crystal mixtures and liquid crystal mixtures containing them.Optically active 1,3-dioxolane-4-carboxylic esters and oxirane-2-carboxylic esters of the general formula (I)R(--A.sup.1).sub.j (--M.sup.1).sub.k (--A.sup.2).sub.l (--M.sup.2).sub.m (--A.sup.3).sub.n --X--Acin whichR.sup.1 is, for example, (C.sub.1 -C.sub.16)-alkyl or (C.sub.1 -C.sub.16)-alkoxy,A.sup.1, A.sup.2, A.sup.3 are, for example, phenyl or pyrimidine-2, 5-diyl,M.sup.1, M.sup.2 are, for example, CO--O, CH.sub.2 --CH.sub.2,j, l are 0, 1, 2,k, m are 0, 1,n is 0, 1, 2,X is O, S andAc is ##STR1## in which R.sup.2, R.sup.3, R.sup.4, R.sup.5, R.sup.6 for example, H or methyl, are particularly suitable doping substances for liquid crystalline mixtures, since they induce a high spontaneous polarization and effect a substantial decrease in the melting point.
Type:
Grant
Filed:
April 17, 1992
Date of Patent:
October 11, 1994
Assignee:
Hoechst Aktiengesellschaft
Inventors:
Wolfgang Hemmerling, Ingrid Muller, Hans-Rolf Dubal, Claus Escher, Gerhard Illian, Mikio Murakami, Dieter Ohlendorf, Rainer Wingen