Abstract: The present invention provides a process for preparing 2,3,3,3-tetrafluoropropene, comprising the following steps: (a) catalytic reaction of 1,1,1,2,3-pentachloropropane and/or 1,1,2,2,3-pentachloropropane with HF into product 2-chloro-3,3,3-trifluoropropene; (b) catalytic reaction of the thus-obtained 2-chloro-3,3,3-trifluoropropene into 2,3,3,3-tetrafluoropropene.

Abstract: The present invention intends to provide a novel cyclohexane compound that can form a liquid crystal composition of which response speed is improved when mixed with a nematic liquid crystal and the like and to provide a specified liquid crystal composition in which a novel cyclohexane compound is mixed. The novel cyclohexane compound is represented by the following formula (1). (In the formula (1), R1 and R2 represent the same or different R, ROCO or RCOO, and the R represents an alkyl group. The alkyl group may have an unsaturated bond, and, in the group, —CH2— may be substituted with —O—, —CO— or —COO—, and a part of or an entirety of hydrogen atoms may be substituted with a halogen atom or a cyano group. X and Y each independently represents a halogen atom or a hydrogen atom and does not simultaneously represent a hydrogen atom. Further, alternatively, X represents an oxygen atom and Y represents a direct bond to the oxygen atom.

Abstract: Disclosed is a process for the manufacture of HFO-1234yf from TCP in three integrated steps that include hydrofluorination of TCP (tetrachloropropene) to HCFC-1233xf in the vapor phase followed by hydrofluorination of HCFC-1233xf to HCFC-244bb in the liquid phase which is then followed by dehydrochlorination in liquid or vapor phase to produce HFO-1234yf. The vapor phase hydrofluorination is carried out at a higher pressure than the liquid phase hydrofluorination, thereby eliminating the need for compression and/or intermediate recovery. Also, any HCl generated from this reaction is fed to the liquid phase hydrofluorination section to promote agitation and mixing. This results in a more economical process from an initial capital and operating cost versus conducting the 3-steps sequentially.

Abstract: The present invention intends to provide a novel cyclohexane compound that can form a liquid crystal composition of which response speed is improved when mixed with a nematic liquid crystal and the like and to provide a specified liquid crystal composition in which a novel cyclohexane compound is mixed. The novel cyclohexane compound is represented by the following formula (1). (In the formula (1), R1 and R2 represent the same or different R, ROCO or RCOO, and the R represents an alkyl group. The alkyl group may have an unsaturated bond, and, in the group, —CH2— may be substituted with —O—, —CO— or —COO—, and a part of or an entirety of hydrogen atoms may be substituted with a halogen atom or a cyano group. X and Y each independently represents a halogen atom or a hydrogen atom and does not simultaneously represent a hydrogen atom. Further, alternatively, X represents an oxygen atom and Y represents a direct bond to the oxygen atom.

Abstract: To provide a liquid crystal compound having general physical properties required for the compound, namely, a high stability to heat, light and so forth, a small viscosity, a refractive index anisotropy value having a suitable magnitude, a dielectric constant anisotropy value having a suitable magnitude and steep electro-optical characteristics, a wide temperature range of a nematic phase, and an excellent compatibility with other liquid crystal compounds, in particular, a liquid crystal compound having a wide temperature range of the nematic phase; the compound is represented by formula (1): wherein R is alkenyl having 2 to 20 carbons; ring A1 and ring A2 are independently 1,4-cyclohexylene, or 1,4-phenylene in which at least one of hydrogen may be replaced by fluorine; Z1 and Z2 are independently a single bond, —CH2CH2—, —CH?CH—, —CH2O— or —OCH2—; and n is 0 or 1.

Abstract: Disclosed is a process for producing tetrafluoropropene comprising: (a) catalytically fluorinating at least one tetrafluoropropene in a first reactor to produce HCFO-1233xf; (b) reacting said HCFO-1233xf with hydrogen fluoride in a second reactor to produce HCFC-244bb; (c) recycling at least a portion of said HCFC-244bb back to said first reactor as recycled HCFC-244bb; and (d) catalytically dehydrochlorinating said recycled HCFC-244bb in said first reactor to produce HFO-1234yf.

Abstract: A method for preparing 2,3,3,3-tetrafluoroprop-1-ene comprising (a) providing a starting composition comprising at least one compound having a structure selected from Formulae I, II and III: CX2?CCl—CH2X??(Formula I) CX3—CCl?CH2??(Formula II) CX3—CHCl—CH2X??(Formula III) wherein X is independently selected from F, Cl, Br, and I, provided that at least one X is not fluorine; (b) contacting said starting composition with a first fluorinating agent to produce a first intermediate composition comprising 2-chloro-3,3,3-trifluoropropene and a first chlorine-containing byproduct; (c) contacting said first intermediate composition with a second fluorinating agent to produce a second intermediate composition comprising 2-chloro-1,1,1,2-tetrafluoropropane and a second chlorine-containing byproduct; and (d) catalytically dehydrochlorinating at least a portion of said 2-chloro-1,1,1,2-tetrafluoropropane to produce a reaction product comprising 2,3,3,3-tetrafluoroprop-1-ene.

Abstract: Cyclopentadienyl and Indenyl barium/strontium metal precursors and Lewis base adducts thereof are described. Such precursors have utility for forming Ba- and/or Sr-containing films on substrates, in the manufacture of microelectronic devices or structures.

Abstract: The present invention relates to cyclobutane and spiro[3.3]heptane compounds, to a process for the preparation thereof, to the use thereof as components in liquid-crystalline media, and to electro-optical display elements which contain these liquid-crystalline media.

Abstract: A liquid crystal compound selected from a group of compounds represented by formula (a): wherein Ra and Rb are each independently alkyl having 1 to 10 carbons, alkoxy having 1 to 9 carbons, alkoxyalkyl having 2 to 9 carbons, alkenyl having 2 to 10 carbons, alkenyloxy having 2 to 9 carbons, fluoroalkyl having 1 to 10 carbons or fluoroalkoxy having 1 to 9 carbons; ring A1, ring A2 and ring A3 are each independently trans-1,4-cyclohexylene, trans-1,3-dioxane-2,5-diyl, trans-tetrahydropyran-2,5-diyl, 1,4-phenylene, 2-fluoro-1,4-phenylene, 2,3-difluoro-1,4-phenylene, 2,5-difluoro-1,4-phenylene, 2,6-difluoro-1,4-phenylene, pyridine-2,5-diyl, 6-fluoropyridine-2,5-diyl or pyridazine-2,5-diyl; Z1, Z2 and Z3 are each independently a single bond, —(CH2)2—, —CH?CH—, —C?C—, —CH2O, —OCH2—, —COO—, —OCO—, —OCF2—, —CF2O—, —CH2CH2OCF2— or —CF2OCH2CH2—; l, m and n are each independently 0, 1 or 2, provided that l+m+n is 0, 1, 2 or 3; one of X1 and X2 is fluorine, and the other is chlorine; Q is and atoms comprising the

Abstract: The present invention relates to cyclopenta[b]naphthalene derivatives to the use thereof in liquid-crystalline or mesogenic media, to liquid-crystalline or mesogenic media comprising at least one of these cyclopenta[b]naphthalene derivatives, and to electro-optical display elements containing these liquid-crystalline or mesogenic media.

Abstract: The present invention relates to compounds of the formula I where X1, X2, R1, R2, A1, A2, Z1, Z2, m, n and rings B and B? are as defined in claim 1.

Abstract: The present invention relates to compounds of the formula I where Y, X1, X2, X3, R1, R2, A1, A2, Z1, Z2, m and n are as defined in Claim 1, to the use thereof as components in liquid-crystalline media, and to electro-optical display elements containing the liquid-crystalline media according to the invention.

Abstract: The invention relates to a process for the preparation of compounds containing at least one —CF2—O— bridge in the molecule, in which a) an acid is added onto at least one ketene dithioketal, b) the resultant bis(alkylthio)carbenium salt is reacted with at least one compound having at least one hydroxyl group in the presence of a base, c) and subsequently, preferably in situ, the resultant dithioorthoester is subjected to oxidative fluorodesulfurisation using a fluorinating agent and an oxidant to give the compound containing at least one —CF2—O— bridge in the molecule.

Abstract: Compounds of the formula (I) in which the parameters are as defined herein, are suitable for use in liquid-crystal media and liquid-crystal displays which contain these media.

Abstract: Compounds that are useful as components in liquid crystal compositions, particularly in ferroelectric liquid crystal compositions. Compounds of the invention are rod-like molecules with a mesogenic (generally linear) core to which an alkene tail and an alkyl or alkoxy tail with a perfluoroalkyl terminal portion are bonded. Compounds of the invention can contain a variety of one, two or three ring cores, wherein the rings maybe aromatic or alicyclic. Alkenes of the invention are useful as components to improve LC properties of mixtures, for example, to lower melting point of lower freezing point, of LC compositions.

Abstract: The invention relates to compounds of the formula (I) having a fluorinated anthracene or fluorinated tetrahydroanthracene core structure and to liquid-crystal mixtures comprising these compounds and to the use thereof in liquid-crystal displays.

Abstract: The present invention relates to oxabicyclooctanes of the general formula I.

Abstract: Described are dialkyne compounds of the formula I in which n, m, R1, R2, X1, X2, X3, X4, Z1, Z2, A1, A2, Q, Y1 and Y2 are as defined herein and the use of such compounds in liquid-crystal media.

Abstract: Functional optical materials for optical systems that are typically useful in optical waveguides, optical switching systems, optical modulators, optical computing systems and the like. Included are polymer systems and electrooptical chromophores. Polymers are thermoplastic and/or thermosetting polymers and are blended or co-polymerized with the electrooptic chromophore. The thermoplastic or thermosetting polymer selected from an acrylic/methacrylic, polyester, polyurethane, polyimide, polyamide, epoxy resin, or hybrid (organic-inorganic) or nanocomposite polyester polymer. The electrooptic chromophore is selected from a substituted aniline, substituted azobenzene, substituted stilbene, or substituted imine. Methods for improving adhesion promotion for the various novel materials are also provided.

Abstract: Fluorinated naphthalene derivatives of the formula (I) R1(—A1—M1)a(—A2—M2)b—B—(—M3—A3)c—(M4—A4)d—R2  (I) where B is  having the meaning  and R1(—A1—M1)a(—A2—M2) and (—M3—A3)(M4—A4)R2 are mesogenic radicals, are suitable as components of liquid-crystal mixtures, in particular ferroelectric liquid-crystal mixtures.

Abstract: The present invention intends to provide a process for producing CF3CF3 with good profitability using CF3CHF2 containing a compound having chlorine atom within the molecule, and use thereof. In the process of the present invention, a gas mixture containing CF3CHF2 and a compound having chlorine atom within the molecule is reacted with hydrogen fluoride in the presence of a fluorination catalyst, thereby converting CClF2CF3 as a main impurity into CF3CF3, and CF3CHF2 containing CF3CF3 is reacted with fluorine gas in the gaseous phase in the presence of a diluting gas.

Abstract: Fluorocyclohexene derivatives of formula I R1—(A1—Z1)n—A—(Z2—A2)m—Z3—B—(Z4—A3)p—R2  I, in which n, m, p, R1, R2, Z1, Z2, Z3, Z4, A1, A2, A3, A and B are as defined herein, are suitable for use in liquid crystal mediums. Also, difluorocyclohexanes of formula III R3—A*—(Z6—A7)m—Z7—Qr—R7  III, where R3, A*, Z6, A7, m, Z7, Q, r, and R4 are as defined herein, are suitable for use in liquid crystal mediums.

Abstract: The invention relates to pentafluorosulfuranylbenzene derivatives of the formula I 1

Abstract: Fluorine-containing, chiral liquid crystal compounds comprise (a) a chiral fluorochemical terminal portion comprising (i) at least one chiral center, which can optionally be heteroatom-substituted; (ii) a terminal fluoroalkyl, fluoroether, perfluoroalkyl, or perfluoroether group; and (iii) an alkylene or fluoroalkylene group optionally containing at least one catenary ether oxygen atom; (b) a chiral or achiral terminal portion consisting of a hydrocarbon or hydrocarbon ether group, and, when chiral, comprising at least one chiral center, which can optionally be heteroatom-substituted; and (c) a central core connecting the terminal portions; the alkylene or fluoroalkylene group of the chiral fluorochemical terminal portion having at least 3 in-chain atoms and being located between the chiral center of the chiral fluorochemical terminal portion and the central core. The compounds have smectic mesophases or latent smectic mesophases and are useful, for example, in liquid crystal display devices.

Abstract: The invention relates to acetylene derivatives of the formula I in which n, m, R1, R2, X1, X2, X3, X4, Z1, Z2, A1, A2, Q, Y1 and Y2 are as defined below, wherein at least one of the groups X1, X2, X3 and X4 is —C≡C—R3, R3 is H, alkyl(C1-C8), Cl, CN, SF5 or CF3.

Abstract: A compound represented by the following general formula (1) is provided. This has broader temperature range of nematic phase, lower viscosity and higher miscibility with other liquid crystal compounds at low temperature than those of conventional liquid crystal compounds, and the compounds have high chemical stability. ##STR1## wherein H.sub.1 to H.sub.8 represent independently a hydrogen atom or a halogen atom, provided that at least one of them is a halogen atom; R.sub.1 represents a moiety which is an alkyl group having 2 to 20 carbon atoms provided that one or more methylene groups (--CH.sub.2 --) which are not successive in the alkyl group are replaced with an oxygen atom (--O--) in the form of ether; Y.sub.1 represents an alkyl group having 1 to 20 carbon atoms, and one or more methylene groups in Y.sub.1 independently may be replaced with an oxygen atom, a sulfur atom, a dihydroxysilyl group, a dimethylsililene group, --CH.dbd.CH-- or --C.tbd.C--; X.sub.1 to X.sub.

Abstract: A process for the catalytic fluorination of hydrochlorocarbons and hydrochlorofluorocarbons in the liquid phase. The process is useful for fluorinating hydrochloropropanes, hydrochlorofluoropropanes, hydrochloropropenes and hydrochlorofluoropropenes and most particularly useful for fluorinating 1,1,1,3,3-pentachloropropane to 1,1,1,3,3-pentafloropropane.

Abstract: Fluorine-containing, chiral liquid crystal compounds comprise (a) a chiral fluorochemical terminal portion containing at least one methylene group and optionally containing at least one catenary ether oxygen atom; (b) a saturated, chiral or achiral, hydrocarbon terminal portion; and (c) a central core connecting the terminal portions. The compounds have smectic mesophases or latent smectic mesophases and are useful, for example, in liquid crystal display devices.

Abstract: Molecular bulding beams, liquid crystals, and surfactants in the form of compounds based on [1.1.1]propellane, including poly[1.1.1]propellanes. Molecular building beams having a telomeric or polymeric chain staff, and linking groups functionalized on one or both ends of the staff. A system for linking the beams to connecting units to construct molecular structures of various forms, such as whips, combs, scaffoldings, nets, or stars. Other broad aspects of the invention provide liquid crystals and surfactants. The liquid crystals include telomeric or polymeric compounds functionalized with flexible end groups, while the surfactant compounds are functionalized with surface active end groups. Methods of synthesizing the various compounds ar also provided.

Abstract: A process for producing an aromatic compound is disclosed, which comprises coupling an aromatic sulfinic acid or a salt thereof with an aromatic halogen compound having at least one halogen atom attached to the carbon atom of the aromatic nucleus thereof or a vinyl group-containing halogen compound having at least one halogen atom attached to the carbon atom of said vinyl group in the presence of a catalyst compound containing an element selected from platinum metals.

Abstract: Carbocyclic compounds of the formula I ##STR1## wherein Q is a benzene or cyclohexane ring or a naphthalene system, X is in each case --CH.sub.2 --(CH.sub.2).sub.p -- where it is also possible for one or two non-adjacent CH.sub.2 groups to be replaced by --O--, --S--, --CO--, --O--CO--, --CO--O-- or --CH.dbd.CH--,p is 0, 1 or 2,A.sup.1 and A.sup.2 independently of one another are each a 1,4-phenylene group which is unsubstituted or monosubstituted or polysubstituted by halogen atoms and/or CH.sub.3 groups and/or CN groups and in which it would also be possible for one or more CH groups to be replaced by N atoms, a 1,4-cyclohexylene group wherein it would also be possible for one or two non-adjacent CH.sub.2 groups to be replaced by --O-- and/or --S--, a piperidine-1,4-diyl group or a 1,4-bicyclo[2.2.2]octylene group,Z is --CO--O--, --O--CO--, --O--, --CH.sub.2 --, --CH.sub.2 O--, --OCH.sub.2 --, --CH.sub.2 CH.sub.2 --, --CHCN--CH.sub.2 --, --CH.sub.2 --CHCN--, --CH.dbd.CH--, --CH.dbd.N--, --N.dbd.CH--, --NO.

Abstract: Cyclohexane derivatives of formula I ##STR1## wherein R is an alkyl group which has 1-12 C atoms and in which one or two non-adjacent CH.sub.2 groups can also be replaced by O, --CO--O-- or --OCO--,A.sup.1 and A.sup.2 each independently of one another are trans-1,4-cyclohexylene or unsubstituted or fluorine-substituted 1,4-phenylene, and one of the groups A.sup.1 and A.sup.2 can also be a single bond,X is --CN, halogen, OH, --COOR.sup.1, --OOCR.sup.1, --COR.sup.1, --OR.sup.1 or R.sup.1 andR.sup.1 is an alkyl group which has 1-12 C atoms and in which one or two CH.sub.2 groups can also be replaced by O, but excluding direct links between two O atoms,with the proviso that, in the case of X=CN, A.sup.2 is trans-1,4-cyclohexylene or fluorine-substituted, 1,4-phenylene, are suitable as components of liquid-crystalline phases.

Abstract: Dispirotetradecanes of the formula I ##STR1## wherein R.sup.1 and R.sup.2 are each independently of each other alkyl containing 1 to 12 carbon atoms wherein one or more non-adjacent CH.sub.2 groups may also be replaced by --O--, --CO--, --CO--O--, --O--CO--, --O--COO-- and/or --CH.dbd.CH-- (trans), one of the radicals R.sup.1 and R.sup.2 also being H, F, Cl, Br, I, CN, NO.sub.2, NCS,A.sup.1 and A.sup.2 are each independently of each other trans-1,4-cyclohexylene wherein one or two non-adjacent CH.sub.2 groups may be replaced by --O-- and/or --S--, or 1,4-phenylene wherein one or more CH groups may also be replaced by N, with it also being possible optionally for A.sup.1 and A.sup.2 to be substituted laterally or axially by F, Cl, CN, CH.sub.3,Z.sup.1 and Z.sup.2 are each independently of each other --C--O--, --O--CO--, --CH.sub.2 CH.sub.2 --, --CH.sub.2 O--, --OCH.sub.2 -- or a single bond,m and n are each 0, 1 or 2,(m+n) 0, 1 or 2,X.sup.1, X.sup.2, X.sup.3 and X.sup.

Abstract: Cyclohexane derivatives of the formula IR.sup.1 --A.sup.1 --Z.sup.1 --A.sup.2 --R.sup.2 Iin whichR.sup.1 and R.sup.2 are each an alkyl group having 1-10 C atoms, in which one or two non-adjacent CH.sub.2 groups can also be replaced by O atoms and/or --CO-- groups and/or --CO--O-- groups and/or --CH.dbd.CH-- groups, one of the radicals R.sup.1 and R.sup.2 also being H, F, Cl, Br, CN or R.sup.3 --A.sup.3 --Z.sup.2 --,A.sup.1 is --A--, A.sup.4 --A-- or --A--A.sup.4 --,A is a trans-1,4-cyclohexylene group which can be substituted in the 2-, 3-, 5- and/or 6-position one or more times by F and/or Cl and/or Br and/or CN and/or an alkyl group or a fluorinated alkyl group which each have 1-10 C atoms and in which one or two non-adjacent CH.sub.2 groups can also be replaced by 0 atoms and/or --CO-- groups and/or --CO--O-- groups, and which may also be substituted in the 1- and/or 4-position,A.sup.2, A.sup.3 and A.sup.

Abstract: New bicyclohexylethanes of formula IR1--Cy--Cy--CH2CH2--A--(Cy)n--R2 (I)wherein R1 is alkyl; R2 is alkyl, in which one or two non-adjacent CH.sub.2 groups can be replaced by 0 atoms, or is F, Cl, Br, CN, --COOalkyl or --O--CO--alkyl; or one of the radicals R.sup.1 and R.sup.2 can also be H; A is Cy, or 1,4-phenylene which is unsubstituted or substituted by one or two F and/or Cl atoms and/or CH.sub.3 groups or by a CN group; Cy is 1,4-cyclohexylene and n is 0 or 1; the alkyl groups in each case containing 1-10 C atoms, with the proviso that n is 1 if A is Cy and R2 is CN, can be used as constituents of dielectrics for electrooptical display elements.

Abstract: New anisotropic compounds of the formula (1) are useful in liquid crystal mixtures for electrooptical displays; at least one of the end groups of the compounds (1) is an alkyl group which carries cyano or halogen in a terminal or non-terminal position. This offers advantages for longitudinal polarization and/or cross-polarization of the anisotropic compounds with the aid of the comparatively highly polarizing cyano or halogen substituents, in particular high clear points, low .DELTA..epsilon./.epsilon..perp. values and/or negative .DELTA..epsilon. values.

Abstract: Bicyclooctane derivatives of the formula IR.sup.1 --A.sup.1 --A.sup.2 --R.sup.2 IwhereinR.sup.1 and R.sup.2 independently of one another are each an alkyl group which has 1-12 C atoms and in which it is also possible for one or two non-adjacent CH.sub.2 groups to be replaced by O atoms and/or CO groups and/or --O13 CO groups and/or --CO--O groups and/or --CH.dbd.CH-- groups, one of the radicals R.sup.1 and R.sup.2 being also --A.sup.3 --R.sup.3,A.sup.1 is a 1,4-cyclohexylene group which is unsubstituted or substituted in the 1-position and/or 2-position and/or 3-position and/or 4-position by alkyl which has in each case 1-5 C atoms and is unsubstituted or substituted or fluorinated, and in which it is also possible for one or two non-adjacent CH.sub.2 groups to be replaced by one or two different groupings from the group --O--, --CO--, --CH.dbd.CH--, --S--, --SO-- or --SO.sub.2 --, or is substituted by F, Cl, Br, CN and/or CHO,A.sup.2 is a 1,4-bicyclo[2.2.2] octylene group,--A.sup.3 --R.sup.3 is --Cy--R.sup.

Abstract: New anisotropic compounds with a cross-polarizing substituent have the formula (1) ##STR1## The increase in .epsilon..perp. is achieved by the polarizing group X, preferably the cyano group or a halogen atom, which is not laterally on the ring, as with the known compounds, but is on the bridge, that is to say is part of the main bridge bonding rings A and B to one another. Ring A has the formula (1a) or (1b) given herein and is always cycloaliphatic, while ring B can be identical to ring A or is an aromatic ring of the formula (1c) or (1d) herein. R.sup.1 and R.sup.2 are identical or different end groups of the formula (1e) herein.The radical X on the bridge causes less widening of the molecule than a radical X on a ring, which provides comparatively higher clear points and moreover enables aromatic rings to be omitted from the anisotropic compounds.

Abstract: Compounds of the formulaR.sup.1 --Q.sup.1 --(CH.sub.2).sub.m --(COO).sub.n --(CH.sub.2).sub.p --Q.sup.2 --R.sup.2whereinR.sup.1 and R.sup.2 are each independently alkyl or alkoxy each of 1-12 C atoms, F, Cl, Br, CN or --Q.sup.3 --R.sup.3, or one of R.sup.1 and R.sup.2 can also be H;Q.sup.1, Q.sup.2 and Q.sup.3 are each independently 1,4-phenylene, 1,4-cyclohexylene, 1,4-bicyclo(2,2,2)-octylene or 1,3-dioxane-2,5-diyl, each of which is unsubstituted or substituted by 1-4 fluorine, chlorine or bromine atoms;R.sup.3 is alkyl or alkoxy each of 1-8 C atoms, H, F, Cl, Br or CN;m is 1, 2, 3, 4, 5 or 6; n is 0 or 1; and p is 0, 1, 2, 3, 4 or 5; the sum of (m+p) being 2, 4 or 6 and the sum of (m+n+p) being at least 3;but with the proviso that Q.sup.3 is unsubstituted 1,4-phenylene or 1,4-phenylene substituted by a fluorine, chlorine or bromine atom, only when n=1 or (m+p)=6 or at least one of R.sup.1 or R.sup.3 is F, Cl or Br or none of R.sup.1 to R.sup.3 is CN or two of the radicals R.sup.1 to R.sup.

Abstract: New bicyclohexylethanes of formula IR.sup.1 --Cy--Cy--CH.sub.2 CH.sub.2 --A--(Cy).sub.n --R.sup.2 (I)wherein R.sup.1 is alkyl; R.sup.2 is alkyl, in which one or two non-adjacent CH.sub.2 groups can be replaced by O atoms, or is F, Cl, Br, CN, --COOalkyl or --O--CO-alkyl; or one of the radicals R.sup.1 and R.sup.2 can also be H; A is Cy, or 1,4-phenylene which is unsubstituted or substituted by one or two F and/or Cl atoms and/or CH.sub.3 groups or by a CN group; Cy is 1,4-cyclohexylene and n is 0 or 1; the alkyl groups in each case containing 1-10 C atoms, with the proviso that n is 1 if A is Cy and R.sup.2 is CN,can be used as constituents of dielectrics for electrooptical display elements.

Abstract: New polyhalogenoaromatic compounds of Formula I ##STR1## wherein Y and Z are each independently alkyl, alkoxy or alkanoyl each of 1 to 12 C atoms, --COOR.sup.1, --O--CO--R.sup.1, CN, NO.sub.2, NH.sub.2 or OH;Q is one or two identical or different radicals selected from Ph, Cy, 1,4-bicyclo[2,2,2]octylene or 1,3-dioxane-2,5-diyl;X.sup.1 to X.sup.4 are each independently H, F, Cl or Br;R.sup.1 is alkyl of 1 to 4 C atoms, Ph--R.sup.2 or Cy--R.sup.2 ;R.sup.2 is alkyl or alkoxy each of 1-12 C atoms or CN;Ph is 1,4-phenylene; and Cy is 1,4-cyclohexylene,can be used as components of liquid-crystal dielectrics.

Abstract: Liquid crystal compounds which exhibit a liquid crystal phase within a broad temperature range and have a high clearing point and nevertheless a low viscosity, and liquid crystal compositions containing the same are provided, which liquid crystal compounds have positive dielectric anisotropy values and are expressed by the general formula ##STR1## wherein R represents hydrogen atom or an alkyl group of 1 to 10 carbon atoms; ##STR2## Y represents H or F; and X represent a halogen atom or CN.

Abstract: Perhydrophenanthrene derivatives of formula I ##STR1## wherein R.sub.1 is alkyl of 1-10 C atoms and R.sub.2 is alkyl, alkoxy or alkanoyloxy each of 1-10 C atoms, H, Br, Cl or CN, have an extremely low optical anisotropy and are particularly suitable as components of liquid-crystalline dielectrics.

Abstract: New liquid crystal compounds having a low viscosity and nevertheless having a high transparent point and a broad nematic temperature range, and liquid crystal compositions containing the same are provided. The compounds are liquid-crystalline halogenobenzene derivatives expressed by the general formula ##STR1## wherein R represents an alkyl group having 1 to 10 carbon atoms; ##STR2## and X and Y each are H, F or Cl, at least one of X and Y being F or Cl.