Patent ID: 7351587
Filing Date: 2008-04-01
Classification: G01N,Y10T

Abstract:
1. A method for continuously oxidizing an alkene, in a synthesis plant comprising a process control system, the method comprising reacting the alkene with hydrogen peroxide in the presence of a catalyst in the synthesis plant, determining, selectively, the hydrogen peroxide content of the reaction mixture on-line by an apparatus for the selective on-line determination of hydrogen peroxide, thereby creating reaction hydrogen peroxide content data, evaluating the data determined by the apparatus by means of at least one data processing unit, and converting the data into control commands for process control of the synthesis plant, wherein the reaction conditions of the alkene with hydrogen peroxide in the presence of the catalyst are altered by the process control system to keep the residual hydrogen peroxide content of the reaction mixture within predetermined limits, wherein the selective on-line determining of the hydrogen peroxide content of the reaction comprises at least the following steps (1) admixing a sample of the reaction mixture comprising hydrogen peroxide with at least one reagent which forms a substance that can be detected by optical methods upon reaction of the reagent with the hydrogen peroxide, so as to form the substance, and (2) determining the amount of the substance present by measuring its specific absorption in an appropriate wavelength range, wherein the at least one reagent comprises a leuco dye and a peroxidase, or is selected from the group consisting of metals of transition groups IV to IX of the Periodic Table of the elements, or is at least one compound selected from the group consisting of titanium-, cobalt-, chromium-, zirconium-, hafnium-, vanadium-, niobium- and tantalum-containing compounds, wherein the apparatus for the selective on-line determining of the hydrogen peroxide comprises at least one sampling device for taking a sample from the reaction mixture formed in the course of the synthesis, at least one sample preparation apparatus, at least one instrument which is capable of determining the specific absorption of the sample in a suitable wavelength range, and at least one component which is connected to the at least one sampling device, the at least one sample preparation apparatus, and the at least one instrument, and performs a control function for, and coordinates the operation of, the at least one sampling device, the at least one sample preparation apparatus, and the at least one instrument, and wherein the at least one data processing unit for evaluating the data determined by the apparatus for the selective on-line determination of hydrogen peroxide and for converting the data into control commands is connected to the apparatus wherein the control commands are then passed on to the process control system of the synthesis plant, which process control system is connected to the at least one data processing unit.