Veb Werk Fur Fernsehelektronik Im Veb Kombinat Mikroelektronik

Veb Werk Fuer Fernsehelektronik Im Veb Kombinat Mikroelektronik

Veb Werk Fur Fernsehdektronik Im Veb Kombinat Mikroelektronik

Hans-Matthias Vorbrodt

Dietrich Demus

Horst Zaschke

Horst Kresse

Wolfgang Weissflog

Adelbert Wiegeleben

Anton Hauser

Wilfried Fuchs

Sylvia Deresh

Jorg Vogel

2-Substituted-5-(1-alkyl-piperid-yl)-1,3-dioxanes of the formula I ##STR1## wherein R= ##STR2## R.sup.1 =--C.sub.n H.sub.2n+1, --OC.sub.n H.sub.2n+1, --OOCC.sub.n H.sub.2n+1, --COC.sub.n H.sub.2n+1, --OOCOC.sub.n H.sub.2n+1, --F, --Cl, --Br, --I, --NO.sub.2, --CN --(CH.sub.2).sub.2 CN, ##STR3## and n=1 to 10, are novel liquid crystalline compounds, which can be produced in high yields by means of reacting 2-(1-alkyl-piperid-4-yl)-propane-1,3-diols with aldehydes in the presence of acid catalysts, such as p-toluenesulfonic acid, mineral acids and Lewis acids. Because of their high thermal and chemical stability, which is also transferred to mixtures, the compounds of the formula I are very well suited for utilization in optoelectronic displays.

Liquid crystalline 2-substituted-5-(1-alkyl-piperid-4-yl)-1,3-dioxanes

Liquid crystal substituted 1,3-dioxanes and mixtures containing the same. The invention relates to liquid crystal substituted 1,3-dioxanes and substances containing the same, for electro-optical arrays for the modulation of incident or transmitted light as well as for the reproduction of figures, symbols and images. The object of the invention is nematic liquid-crystal substances with favorable properties with respect to melting and clear points, stability toward thermal stress, effect of light, chemicals and electric fields as well as loss of color and processes for their production. The object is accomplished by the creation of new nematic liquid-crystal substances. According to the invention, liquid crystal 2,5-disubstituted derivatives of 1,3-dioxane of the general formula ##STR1## are proposed, wherein ##STR2## The new substances may be used in mixtures containing at least one of the substances according to the invention.

Liquid crystal substituted 1,3-dioxanes and mixtures containing them

The invention relates to nematic liquid crystals, especially for electro-optical components for the modulation of transmitted or reflected light, as well as for the display of numbers, symbols and images, exhibiting favorable physical characteristics, as well as to a method for the production of the new substances. It has been found that new liquid crystal 2-substituted-1,3-dioxane-5-carboxylic acid esters of the general formula ##STR1## are suited for use in electro-optical components for the modulation of the light, as well as for the display of numbers, symbols and images, and can be used alone, in mixtures with each other and/or in mixtures with additional liquid crystal or non-liquid crystal substances. In the method for the production of the new liquid crystal trans-2-substituted-1,3-dioxane-5-carboxylic acid esters, 2-substituted-1,3-dioxane carboxylic acids, with halogen donors such as thionyl chloride, sulfuryl chloride or phosphoric halides, preferably in the absence of organic bases, are converted into the corresponding acid chlorides, which are subsequently esterified in well-known fashion with alcohols or substituted phenols.

Nematic liquid crystals and method for production thereof

The invention relates to liquid crystal nematic substances based on new derivatives of 1,3-dioxanes in electro-optical components, which are used, for instance, as displays in electronic clocks and computer systems. The subject of the invention is nematic liquid crystal substances with favorable properties concerning melting and clear temperatures, stability against thermal stress and electrical fields, low viscosity and low threshold voltage. It was found that liquid crystal 2,5-di-substituted cyclohexyl derivatives of 1,3 dioxanes, having the general formula ##STR1## R.sup.1 =C.sub.n H.sub.2n+1 ; C.sub.n H.sub.2n+1 O; C.sub.n H.sub.2n+1 COO; CN; NO.sub.2 ; F; Cl; Br

Liquid crystalline nematic substances

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Quedlinburg, Germany

Hans-Matthias Vorbrodt