Oxidation of isobutane to TBHP – a chemical process with high energy saving potential.


Oxidation of isobutane to TBHP – a chemical process with high energy saving potential.

Willms, T.; Kryk, D. H.; Hampel, U.

Tertiary butyl hydroperoxide (TBHP), as an intermediate for the production of propylene oxide according to the Oxirane process, is currently produced at industrial scale by the partial oxidation of liquid isobutane using bubble columns or bubble tray reactors. In this process, liquid isobutane reacts with oxygen under two phase conditions at temperatures of 120 to 140 °C and pressures of 25 to 37 bars at high residence times of up to 12 hours. The conversion is limited to 35 to 50 % in order to obtain a TBHP selectivity of 50 to 60 % minimizing the formation of by-products, which are caused by the decomposition of the TBHP due to the complex reaction mechanism. Besides safety aspects, the high reaction enthalpy of the oxidation as well as heat and mass transport problems are further issues of this process. In the frame of the Helmholtz-Energy-Alliance project “Energy efficient chemical multiphase processes“, this reaction is investigated for the first time at supercritical conditions using DTBP as an initiator in a broad range of flow rates, temperatures and pressures in a micro reactor with the aim to enhance the space-time yield of the process. The advantage of micro reactors are the high surface – volume ratio for an efficient heat transfer, the related, improved – nearly inherent – safety and the resulting possibility to investigate unusual process windows, for instance within the explosive region of a reaction mixture using high oxygen concentrations. Besides two phase flow conditions, super¬critical conditions i.e. pressures above 40 bars and temperatures above 140°C are especially interesting because of the higher reaction rate and lacking mass transfer limitations. The reaction has been performed in both regimes at different conditions and the results compared. Furthermore, the influence of process parameters on the start-up time has been investigated. For all experiments, the selectivity and conversion of the reaction have been studied. Therefor, the reaction course is followed by sampling and analyzing the reaction by GC/MS and GC–TCD where analytical methods have been developed to detect a maximum of by-products and inter¬mediates.

Keywords: isobutane; oxidation; energy efficiency; t-butyl hydroperoxide; micro reactor

  • Poster
    Jahrestreffen Frankfurt I Jahrestreffen der ProcessNet-Fachgruppen Hochdruckverfahrenstechnik, Mikroverfahrenstechnik, Molekulare Modellierung, 08.-10.03.2017, Frankfurt, Deutschland
  • Contribution to proceedings
    Jahrestreffen Frankfurt I Jahrestreffen der ProcessNet-Fachgruppen Hochdruckverfahrenstechnik, Mikroverfahrenstechnik, Molekulare Modellierung, 08.-10.03.2017, Frankfurt, Deutschland

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Publ.-Id: 25786