The present invention relates to compounds of the formula I ##STR00001##
where one or more of the radicals A.sup.1-5 denote a 1,4-naphthylene or 1,4- or 9,10-anthracenylene radical, and the other parameters are as defined in Claim 1. The invention additionally includes liquid-crystalline media which comprise the title compounds, and components for high-frequency technology which comprise these media, in particular phase shifters and microwave array antennae.

Provided is a method for industrially producing a conjugated Z-alken-yn-yl acetate such as Z-13-hexadecen-11-yn-yl acetate which is a sex pheromone component of a pine processionary moth, and an intermediate for the conjugated Z-alken-yn-yl acetate under mild conditions at a high yield. More specifically, provided is a method for producing a conjugated Z-alken-yn-yl acetate (5) comprising the steps of: reacting an -halo-2-alkynal (1) with an alkylidene triphenylphosphorane (3) through a Wittig reaction to obtain a conjugated Z-alken-yn-yl halide (4), and acetoxylating the conjugated Z-alken-yn-yl halide (4) into a conjugated Z-alken-yn-yl acetate (5). ##STR00001##

Provided is a method for industrially producing a conjugated Z-alken-yn-yl acetate such as Z-13-hexadecen-11-yn-yl acetate which is a sex pheromone component of a pine processionary moth, and an intermediate for the conjugated Z-alken-yn-yl acetate under mild conditions at a high yield. More specifically, provided is a method for producing a conjugated Z-alken-yn-yl acetate (5) comprising the steps of: reacting an -halo-2-alkynal (1) with an alkylidene triphenylphosphorane (3) through a Wittig reaction to obtain a conjugated Z-alken-yn-yl halide (4), and acetoxylating the conjugated Z-alken-yn-yl halide (4) into a conjugated Z-alken-yn-yl acetate (5). ##STR00001##

Processes are provided for (i) producing Z-1,1,1,4,4,4-hexafluoro-2-butene (ZCF.sub.3CHCHCF.sub.3) from E-1,1,1,4,4,4-hexafluoro-2-butene (E-CF.sub.3CHCHCF.sub.3), comprising the steps of (a) reacting the E-1,1,1,4,4,4-hexafluoro-2-butene (E-CF.sub.3CHCHCF.sub.3) with chlorine to form dichloro-1,1,1,4,4,4-hexafluorobutane (CF.sub.3CHClCHClCF.sub.3), (b) recovering the dichloro-1,1,1,4,4,4-hexafluorobutane from step (a), (c) reacting the recovered dichloro-1,1,1,4,4,4-hexafluorobutane with base to form 1,1,1,4,4,4-hexafluoro-2-butyne (CF.sub.3CCF.sub.3), (d) recovering the 1,1,1,4,4,4-hexafluoro-2-butyne from step (c) and (e) reacting the recovered hexafluoro-2-butyne with hydrogen to form said Z-1,1,1,4,4,4-hexafluoro-2-butene, optionally wherein said E-1,1,1,4,4,4-hexafluoro-2-butene starting material is obtained by converting 1,1,1,4,4,4-hexafluoro-2-butane (F.sub.3CHCl.sub.2) to a mixture of Z-1,1,1,4,4,4-hexafluoro-2-butene and E-1,1,1,4,4,4-hexafluoro-2-butene and recovering the E-1,1,1,4,4,4-hexafluoro-2-butene from said mixture, whereby the E-1,1,1,4,4,4-hexafluoro-2-butene used in step (a) is the recovered E-1,1,1,4,4,4-hexafluoro-2-butene, and (ii) step (a) as a subcombination of the process (i).

Processes are provided for (i) producing Z-1,1,1,4,4,4-hexafluoro-2-butene (ZCF.sub.3CHCHCF.sub.3) from E-1,1,1,4,4,4-hexafluoro-2-butene (E-CF.sub.3CHCHCF.sub.3), comprising the steps of (a) reacting the E-1,1,1,4,4,4-hexafluoro-2-butene (E-CF.sub.3CHCHCF.sub.3) with chlorine to form dichloro-1,1,1,4,4,4-hexafluorobutane (CF.sub.3CHClCHClCF.sub.3), (b) recovering the dichloro-1,1,1,4,4,4-hexafluorobutane from step (a), (c) reacting the recovered dichloro-1,1,1,4,4,4-hexafluorobutane with base to form 1,1,1,4,4,4-hexafluoro-2-butyne (CF.sub.3CCF.sub.3), (d) recovering the 1,1,1,4,4,4-hexafluoro-2-butyne from step (c) and (e) reacting the recovered hexafluoro-2-butyne with hydrogen to form said Z-1,1,1,4,4,4-hexafluoro-2-butene, optionally wherein said E-1,1,1,4,4,4-hexafluoro-2-butene starting material is obtained by converting 1,1,1,4,4,4-hexafluoro-2-butane (F.sub.3CHCl.sub.2) to a mixture of Z-1,1,1,4,4,4-hexafluoro-2-butene and E-1,1,1,4,4,4-hexafluoro-2-butene and recovering the E-1,1,1,4,4,4-hexafluoro-2-butene from said mixture, whereby the E-1,1,1,4,4,4-hexafluoro-2-butene used in step (a) is the recovered E-1,1,1,4,4,4-hexafluoro-2-butene, and (ii) step (a) as a subcombination of the process (i).

Processes for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene and intermediates for producing same. A process for producing 2-chloro-1,1,1,4,4,4-hexafluorobutane comprises contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with HF in the liquid phases. A process for producing E-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 2-chloro-1,1,1,4,4,4-hexafluorobutane with base. A process for producing 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane comprises contacting E-1,1,1,4,4,4-hexafluorobut-2-ene with a chlorine source. A process for producing 1,1,1,4,4,4-hexafluoro-2-butyne comprises contacting 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane with a base. A process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen and a catalyst.

Processes for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene and intermediates for producing same. A process for producing 2-chloro-1,1,1,4,4,4-hexafluorobutane comprises contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with HF in the liquid phases. A process for producing E-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 2-chloro-1,1,1,4,4,4-hexafluorobutane with base. A process for producing 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane comprises contacting E-1,1,1,4,4,4-hexafluorobut-2-ene with a chlorine source. A process for producing 1,1,1,4,4,4-hexafluoro-2-butyne comprises contacting 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane with a base. A process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 1,1,1,4,4,4-hexafluoro-2-butyne with hydrogen and a catalyst.

A process for producing E-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with hydrogen fluoride in the vapor phase in the presence of a fluorination catalyst. A process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene further comprises contacting E-1,1,1,4,4,4-hexafluoro-2-butene with chlorine in the presence of a catalyst to produce 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane, followed by reaction with base to produce 1,1,1,4,4,4-hexafluoro-2-butyne, and subsequently hydrogenating hexafluoro-2-butyne to produce Z-1,1,1,4,4,4-hexafluoro-2-butene.

A process for producing E-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with hydrogen fluoride in the vapor phase in the presence of a fluorination catalyst. A process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene further comprises contacting E-1,1,1,4,4,4-hexafluoro-2-butene with chlorine in the presence of a catalyst to produce 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane, followed by reaction with base to produce 1,1,1,4,4,4-hexafluoro-2-butyne, and subsequently hydrogenating hexafluoro-2-butyne to produce Z-1,1,1,4,4,4-hexafluoro-2-butene.

A process for producing E-1,1,1,4,4,4-hexafluorobut-2-ene comprises contacting 1,1,2,4,4-pentachlorobuta-1,3-diene with hydrogen fluoride in the vapor phase in the presence of a fluorination catalyst. A process for producing Z-1,1,1,4,4,4-hexafluorobut-2-ene further comprises contacting E-1,1,1,4,4,4-hexafluoro-2-butene with chlorine in the presence of a catalyst to produce 2,3-dichloro-1,1,1,4,4,4-hexafluorobutane, followed by reaction with base to produce 1,1,1,4,4,4-hexafluoro-2-butyne, and subsequently hydrogenating hexafluoro-2-butyne to produce Z-1,1,1,4,4,4-hexafluoro-2-butene.