The present invention relates to a process for preparing alpha-hydroxycarboxylic esters proceeding from hydrogen cyanide, wherein the ammonia formed in the step of alcoholysis of the corresponding alpha-hydroxycarboxamide is recycled into a hydrogen cyanide preparation process after a purification step.

Described herein is a gaslight multilayered composite tube having a heat transfer coefficient of >500 W/m.sup.2/K which in its construction over the cross section of the wall of the composite tube includes as an inner layer a nonporous monolithic oxide ceramic surrounded by an outer layer of oxidic fiber composite ceramic, where this outer layer has an open porosity of 5%<ε<50%, and which on the inner surface of the composite tube includes a plurality of depressions oriented towards the outer wall of the composite tube. Also described herein is a method of using the multilayered composite tube as a reaction tube for endothermic reactions, jet tubes, flame tubes or rotary tubes.

A reactor system for carrying out an endothermic reaction of a feed gas, including: a structured catalyst arranged for catalyzing the endothermic reaction of a feed gas, the structured catalyst including a macroscopic structure of electrically conductive material, the macroscopic structure supporting a ceramic coating, wherein the ceramic coating supports a catalytically active material; a pressure shell housing the structured catalyst; heat insulation layer between the structured catalyst and the pressure shell; at least two conductors electrically connected to the electrically conductive material and to an electrical power supply placed outside the pressure shell, wherein the electrical power supply is dimensioned to heat at least part of said structured catalyst to a temperature of at least 200° C. by passing an electrical current through the electrically conductive material. Also, a process for performing an endothermic reaction of a feed gas.

A device and a method are provided for reacting a starting material in at least two reactors connected to each other, including the reacting of the starting material in a first reactor to a first product, removing the first product from the first reactor using a jet pump, wherein a negative pressure zone of the jet pump is operationally connected to the first reactor, so that the first product of the first reactor moves through the negative pressure zone in a propulsion jet of a propulsion medium of the jet pump, conducting the propulsion medium having the first product into a second reactor, wherein the first product is allowed to react into a second product, separating the second product from the propulsion medium and discharging the separated second product.

Process for making purified hydrogen cyanide. The process includes feeding a reaction product including HCN, water, and organonitriles to a separation vessel; taking a liquid slip stream of HCN, water and organonitriles from the separation vessel; and feeding the liquid slipstream into a sidestream stripper to purge nitriles from the HCN reaction product.

The present invention relates to a process for preparing alpha-hydroxycarboxylic esters proceeding from hydrogen cyanide, wherein the ammonia formed in the step of alcoholysis of the corresponding alpha-hydroxycarboxamide is recycled into a hydrogen cyanide preparation process after a purification step.

Process for making purified hydrogen cyanide. The process includes feeding a reaction product including HCN, water, and organonitriles to a separation vessel; taking a liquid slip stream of HCN, water and organonitriles from the separation vessel; and feeding the liquid slipstream into a sidestream stripper to purge nitriles from the HCN reaction product.

A reactor system for carrying out an endothermic reaction of a feed gas, including: a structured catalyst arranged for catalyzing the endothermic reaction of a feed gas, the structured catalyst including a macroscopic structure of electrically conductive material, the macroscopic structure supporting a ceramic coating, wherein the ceramic coating supports a catalytically active material; a pressure shell housing the structured catalyst; heat insulation layer between the structured catalyst and the pressure shell; at least two conductors electrically connected to the electrically conductive material and to an electrical power supply placed outside the pressure shell, wherein the electrical power supply is dimensioned to heat at least part of said structured catalyst to a temperature of at least 200 C. by passing an electrical current through the electrically conductive material. Also, a process for performing an endothermic reaction of a feed gas.

Endothermic reactions (those whose heat of reaction is positive) may be controlled in a truly isothermal fashion with external heat input applied directly to the solid catalyst surface itself and not by an indirect means external to the actual catalytic material. This heat source can be supplied uniformly and isothermally to the catalyst active sites solely by conduction using electrical resistance heating of the catalytic material itself or by an electrical resistance heating element with the active catalytic material coating directly on the surface. By employing only conduction as the mode of heat transfer to the catalytic sites, the non-uniform modes of radiation and convection are avoided permitting a uniform isothermal chemical reaction to take place.

A process for carrying out an endothermic reaction of a feed gas in a reactor system including a pressure shell housing a structured catalyst arranged for catalyzing the endothermic reaction of a feed gas, the structured catalyst including a macroscopic structure of electrically conductive material, the macroscopic structure supporting a ceramic coating, the ceramic coating supporting a catalytically active material.