摘要:
The invention relates to a process for preparing aromatic amines by hydrogenation of nitroaromatics in the presence of catalysts, in which a fluid reaction mixture which comprises amines and from which the catalysts are separated off is formed in a reactor. After the catalysts have been separated off, a measurement of the absorption of UV/VIS radiation by the reaction mixture is carried out to determine the concentration of nitro and nitroso compounds in the reaction mixture.
摘要:
The invention relates to a process for preparing aromatic amines by hydrogenation of nitroaromatics in the presence of catalysts, in which a fluid reaction mixture which comprises amines and from which the catalysts are separated off is formed in a reactor. After the catalysts have been separated off, a measurement of the absorption of UV/VIS radiation by the reaction mixture is carried out to determine the concentration of nitro and nitroso compounds in the reaction mixture.
摘要:
The disclosure is a probelike apparatus (16) for spectroscopic analysis of a fluid medium (19) by attenuated reflection. Two light beams from a light source (11) impinge upon the boundary (18) between a prism (17) and the medium (19) to be analyzed and the intensities of the light beams reflected at the boundary are measured in a detector unit (22). The two light beams differ in their angle of incidence on the boundary and/or in their polarization state. Measurement is preferably carried out under total reflection.
摘要:
A process for the on-line determination of the hydrogen peroxide content of a mixture obtained in a chemical reaction comprises at least the following steps: (1) admixing the mixture comprising hydrogen peroxide with at least one reagent which is capable of forming a substance which can be detected by optical methods on reaction with hydrogen peroxide, so as to form this substance, (2) determining the amount of the substance present by measuring its specific absorption in an appropriate wavelength range.