Basf Aktiengesellschaft

Manfred Braun

Gerd Kaibel

Sylke Haremza

Axel Nissen

Frank Prechtl

Walter Rebafka

Robert Parker

Lothar Arnold

Otto Woerz

Kathrin K&uuml;rschner

Ralf Fleischer

Antje Hahn

Improved liquid crystalline materials may be prepared by doping liquid crystalline materials with chiral, uncharged metal compounds of formula &lsqb;(P &mdash;Y &mdash;A &mdash;Y &mdash;M &mdash;Y &mdash;) L&rsqb; Me or &lsqb;(P &mdash;Y &mdash;A &mdash;Y &mdash;M &mdash;Y &mdash;) L&rsqb;Me(L&prime;(&mdash;Y &mdash;M &mdash;Y &mdash;A &mdash;Y &mdash;P ) ) . Groups P and P may be, independently, hydrogen, C -C -alkyl groups, polymerizable groups, or radicals containing a polymerizable group. Y to Y may be, independently, single chemical bonds, ether groups, thio groups, carbonyl groups, acid groups, etc. Groups A and A are spacers having from 1 to 30 carbon atoms, and M and M are mesogenic groups. Me may be a transition metal from the fourth, fifth or sixth period of the periodic table, except for technetium, silver, cadmium, gold, mercury, or any of the lanthanoids, or Me may be a main group element from group 14 (IUPAC system), except for carbon and lead. L is a tridentate ligand, and L&prime; is an organic group having up to 12 carbon atoms.

Use of chiral, uncharged metal compounds as dopants for liquid-crystalline materials

An improved process for the preparation of higher unsaturated ketones, such as geranylacetone and farnesylacetone, by reacting a .beta.,.gamma.-unsaturated alcohol and an alkyl acetoacetate at an elevated temperature in the presence of an organic aluminum compound, with elimination, and removal, of the alcohol derived from the alkyl acetoacetate in a reactor system carrying a fractionating column. The improvement in the purity, yield, and especially space-time yield of the product is achieved by starting from an alcohol having a higher boiling point than that of the alkyl acetoacetate used, carrying out the reaction in the presence of a small amount of an inert liquid which has a boiling point between that of the alkyl acetoacetate and the alcohol to be eliminated therefrom, and ensuring that the temperature at the bottom of the fractionating column is only slightly higher than the boiling point of the added liquid, under the prevailing pressure.

Preparation of higher unsaturated ketones

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Schifferstadt, Germany

Manfred Braun