Geminal dimethylalkyl compounds, process for their preparation and their use in liquid-crystalline mixtures

US5366657A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Gerhard Illian · Frankfurt am Main, DE
• Ingrid Muller · Niedernhausen, DE
• Takamasa Harada · Oberursel, DE

Key dates

• Filing date: Jul 24, 1992
• Grant date: Nov 22, 1994
• Expiry date: Jul 24, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C09K19/3497
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Geminal dimethylalkyl compounds, process for their preparation and their use in liquid-crystalline mixtures Geminal dimethylalkyl compounds of the formula (I) ##STR1## in which: R.sup.1 is, for example, straight-chain or branched (with or without an asymmetric carbon atom) alkyl or alkenyl having 2 to 16 carbon atoms, PA1 A.sup.1, A.sup.2 and A.sup.3 are, for example, identical or different 1,4-phenylene, 1,4-cyclohexylene or pyrimidine-2,5-diyl, PA1 M.sup.1 and M.sup.2 are, for example, identical or different CO--O or O--CO, PA1 G is for example, identical or different straight-chain or branched alkylene having 1 to 16 carbon atoms, PA1 k, l, m and n are zero or 1, and PA1 R.sup.6 is straight-cain alkyl having 1 to 10 carbon atoms, can advantageously be employed in liquid-crystalline mixtures. In liquid-crystalline mixtures, said compounds result in a melting point depression, in a shift in the temperature limit of the S.sub.c phase in ferroelectric mixtures and in other improvements of important electrooptical characteristic values.