Abstract: The present invention relates to a liquid-crystalline medium (LC medium), to the use thereof for electro-optical purposes, and to LC displays containing this medium.

Abstract: The present disclosure relates to a process for producing chlorosilanes by reaction of a reaction gas containing hydrogen, tetrachlorosilane and optionally at least one further chlorosilane in a reactor and optionally in the presence of a catalyst. The chlorosilanes have the general formula HnSiCl4-n, and the reactor design is described by an index K1, the composition of the reaction gas before entry into the reactor is described by an index K2, and the reaction conditions are described by an index K3.

Abstract: The invention relates to a process for hydrogenating silicon tetrachloride in a reactor, wherein a reactant gas containing hydrogen and silicon tetrachloride is heated to a temperature between 850° C. and 1600° C. by means of at least one heating element, which comprises a graphite surface, wherein the temperature of the heating element is between 850° C. and 1600° C. The process is characterized in that a nitrogen compound is added to the reactant gas in a substance amount fraction of 0.1 to 10% based on hydrogen.

Abstract: The invention relates to a process bit hydrogenating silicon tetrachloride in a reactor, wherein a reactant gas containing hydrogen and silicon tetrachloride is heated to a temperature between 850° C. and 1600° C. by means of at least one heating element, which comprises a graphite surface, wherein the temperature of the heating element is between 850° C. and 1600° C. The process is characterized in that a nitrogen compound is added to the reactant gas in a substance amount fraction of 0.1 to 70% based on hydrogen.

Abstract: The invention provides a process for endothermic gas phase reaction in a reactor, in which reactant gases are introduced into the reactor via a gas inlet apparatus and distributed homogeneously into a heating zone by means of a gas distribution apparatus, wherein the reactant gases are heated in the heating zone to a mean temperature of 500-1500° C. by means of heating elements and then conducted into a reaction zone, the reactant gases reacting in the reaction zone to give a product gas which is conducted out of the reactor via a gas outlet apparatus. Further subject matter of the invention relates to a process for endothermic gas phase reaction in a reactor, wherein the heating of the heating elements is controlled by temperature measurements in the reaction zone, at least two temperature sensors being present in the reaction zone for this purpose, and reactor for performance of the process.

Abstract: The invention provides a process for hydrogenating silicon tetrachloride in a reactor, in which reactant gas containing hydrogen and silicon tetrachloride is heated to a temperature of greater than 900° C. at a pressure between 4 and 15 bar, first by means of at least one heat exchanger made from graphite and then by means of at least one heating element made from SiC-coated graphite, the temperature of the heating elements being between 1150° C. and 1250° C., wherein the reactant gas includes at least one boron compound selected from the group consisting of diborane, higher boranes, boron-halogen compounds and boron-silyl compounds, the sum of the concentrations of all boron compounds being greater than 1 ppmv based on the reactant gas stream.

Abstract: The invention provides a process for endothermic gas phase reaction in a reactor, in which reactant gases are introduced into the reactor via a gas inlet apparatus and distributed homogeneously into a heating zone by means of a gas distribution apparatus, wherein the reactant gases are heated in the heating zone to a mean temperature of 500-1500° C. by means of heating elements and then conducted into a reaction zone, the reactant gases reacting in the reaction zone to give a product gas which is conducted out of the reactor via a gas outlet apparatus. Further subject matter of the invention relates to a process for endothermic gas phase reaction in a reactor, wherein the heating of the heating elements is controlled by temperature measurements in the reaction zone, at least two temperature sensors being present in the reaction zone for this purpose, and reactor for performance of the process.