Continuous Liquid-Phase Epoxidation of Ethylene with Hydrogen Peroxide on a Titanium-Silicate Catalyst

Abstract

Ethylene epoxidation with hydrogen peroxide was studied in a laboratory-scale trickle bed reactor under a broad range of experimental conditions (15–80 °C, 2.5–8.5 bar) utilizing a commercial titanium-silicate catalyst (TS-1). The catalyst was very stable and selective over 150 h time-on-stream. The main reaction product was ethylene oxide, while 2-methoxyethanol and ethylene glycol were observed as kinetic byproducts. In most of the experiments, ethylene glycol was not detected at all. An increase in temperature and pressure affected negatively the ethylene oxide selectivity, while an increase in the hydrogen peroxide concentration improved both the ethylene oxide selectivity and ethylene conversion. Ethylene epoxidation was comparable with propylene epoxidation, displaying, however, important differences in activity and selectivity, which were attributed to the partial pressures studied in the present work. It was demonstrated that TS-1 is a very selective and active catalyst for the selective epoxidation of ethylene with hydrogen peroxide.

Molecular Structure Effect on the Epoxidation of 1-Butene and Isobutene on the Titanium Silicate Catalyst under Transient Conditions in a Trickle Bed Reactor

“…The standard deviation in the conversion measurements was higher during the first 4 h and it was defined to be less than 5% after that period, whereas for the selectivity results, the deviations were less than 0.1%. The TOS behavior of 1-butene displayed to be different from ethene and propene epoxidation. In ethene and propene, the steady state was reached after 2.5 h. , However, 1-butene reached stability after 12 h, almost five times longer than shorter olefins.…”

“…Commercial titanium silicalite (TS-1) of ACS (Advance Chemical Supplier) material type B was the catalyst employed: CAS No. 13463-67-7 (titanium dioxide)/7621-86-9 (silicon dioxide); the microporous Ti–Si molecular sieve was prepared by a hydrothermal method . The surface area, pore size distribution, and pore volume of the catalyst material were measured with nitrogen physisorption using Micromeritics 3 Flex equipment.…”

Process Intensification in Chemical Reaction Engineering

“…Thus, it is possible to obtain the intrinsic kinetics of the system. When surface reactions are under investigation, transient operations can be of high impact, as they allow for collection of a large amount of steady-state data in one experiment [133,134] in order to distinguish between reaction mechanisms.…”

Cyclic carbonates as building blocks for non‐isocyanate polyurethanes

“…Cyclic carbonates, such as EC, propylene carbonate (PC), and butylene carbonate (BC), can be synthetized from CO 2 and diols 16 or epoxides 17 when a right catalyst is used 18 . Furthermore, it is possible to achieve fully bio‐ or CO 2 based cyclic carbonates if the epoxide is manufactured from bio‐ethanol, bio‐naphtha, 19 or epoxidized light olefin produced from CO 2 20 . Light olefins can be synthetized directly from CO 2 and hydrogen with a novel reverse water gas shift (RWGS) reaction followed by a Fischer–Tropsch (FT) reaction 21 .…”

“…18 Furthermore, it is possible to achieve fully bio-or CO 2 based cyclic carbonates if the epoxide is manufactured from bio-ethanol, bio-naphtha, 19 or epoxidized light olefin produced from CO 2 . 20 Light olefins can be synthetized directly from CO 2 and hydrogen with a novel reverse water gas shift (RWGS) reaction followed by a Fischer-Tropsch (FT) reaction. 21 Therefore, these monocyclic carbonates enable an attractive way of making more environmentally benign NIPU with the polycondensation method.…”