Abstract:
A process for monitoring and/or controlling a nitrating process, having the following steps: measuring inline infrared spectra of nitric acid content in a reaction mixture stream downstream of the nitration reaction, preferably near-infrared spectra, evaluating the measured spectra by means of a computer-assisted, matrix-specific calibration model for the purpose of determining the content of nitric acid, transmitting the results of spectrometric examination to a process control system, inputting the results of spectrometric examination for the purpose of specifying the content of nitric acid in the acid phase into a regulator (224) for control of the metering (207,217) of nitric acid into a nitrating reactor.
Abstract:
Optical fibres, and a process for their production, are described which comprise tubular plastic cladding and a core of a polymer whose refractive index is at least 1% greater than that of the cladding material. The core is obtained from a polymerisable mixture which comprises compounds containing epoxy groups, of which at least 10% by weight are siloxanes containing epoxy groups.