GB363028A - A process and apparatus for subjecting one or more components of mixtures of hydrocarbons to exothermic chemical reactions - Google Patents

Abstract

Exothermic chemical reactions between a mixture of hydrocarbons and a reagent having a preferential affinity for one or more components of the mixture are effected by introducing the mixture in the liquid state into a reaction zone in which it is treated with liquid reagent, causing part of the hydrocarbon mixture to evaporate in the reaction zone, the reagent remaining liquid, wholly or partly condensing the vapours evolved, and introducing a whole or part of the condensate into the reaction zone in order to control the temperature therein, if desired, maintaining it below atmospheric temperature. The process may be carried out in apparatus comprising a reaction vessel, a reflux condenser, which may be either a heat-exchanger of the usual type, or a compresser and cooler, and means for introducing the hydrocarbons condensed therein into the reaction vessel at a plurality of points to control the reaction temperature.ALSO:<PICT:0363028/IV/1> Alkyl sulphates; mono-nitrobenzene. --Exothermic chemical reactions between a mixture of hydrocarbons and a reagent having a preferential affinity for one or more components of the mixture are effected by introducing the mixture in the liquid state into a reaction zone in which it is treated with the liquid reagent, causing part of the hydrocarbon mixture to evaporate in the reaction zone, the reagent remaining liquid, wholly or partly condensing the vapours evolved, and introducing a whole or part of the condensate into the reaction zone in order to control the temperature therein. If desired, the temperature in the reaction zone may be maintained in this way below atmospheric temperature without the use of external refrigeration. The process is applicable to reactions between sulphuric acid and mixtures of hydrocarbons containing paraffins and olefines, for example, a mixture of propane and propylene or a mixture of butane and butylene, or to the treatment of a mixture of benzene and n-butane with nitric acid to convert the benzene into mono-nitrobenzene. Suitable apparatus for carrying out the process comprises a reaction vessel, a reflux condenser, which may either be a heat-exchanger of the usual type or a compresser and cooler, and means for introducing the hydrocarbons condensed therein into the reaction vessel at a plurality of points in regulated quantities to control the reaction temperature. According to an example, a mixture of propylene and propane is treated with sulphuric acid in a column 6 which is packed with rings or other suitable packing material, except for a space 7 into which the hydrocarbon mixture is introduced in liquid form through a spray nozzle from a pipe 8. The sulphuric acid is introduced into the column from lines 9, 11. The heat produced in the reaction between the sulphuric acid and propylene vaporizes some of the hydrocarbon mixture, which leaves the column by a line 18 and is condensed in a condenser 16. The condensate passes down a line 19, and may be in part removed from the system through a valve 22, in part returned to the column 6 through a line 23 and valve 26, and in part through a line 24 and valve 27. The propylene-sulphuric acid is withdrawn from a settling tank 31 through a valve 33. A heating coil 34 is provided in the tank 31 to vaporize any unreacted hydrocarbon contained therein; or the layer of unreacted hydrocarbon may be drawn off through a valve 35. An inert volatile diluent may be introduced into the reaction zone if sufficient cooling is not obtained by circulating some of the volatile reactant, in this case propylene, or by allowing the hydrocarbon diluent to accumulate in the system. Suitable reaction temperatures and pressures are -5 DEG F. and 20 lbs. per square inch in the case of a propane-propylene mixture, and 90 DEG F. and 30 lbs. per square inch in the case of a butane-butylene mixture.