Author(s):
1. Rada Petrovic, Faculty of Technology Banja Luka, Republic of Srpska, Bosnia and Herzegovina
2. Jelena Penavin-Škundrić, Prirodno-matematički fakultet Banja Luka, Republic of Srpska, Bosnia and Herzegovina
3. Branko Škundrić, Akademija nauka i umjetnosti Republike Srpske, Republic of Srpska, Bosnia and Herzegovina
4. Nedeljko Cegar, Faculty of Technology Banja Luka, Republic of Srpska, Bosnia and Herzegovina

Abstract:
The speed of diethyl ether dehydration reaction was examined in the static system on H-forms of mordenite (HM) and ZSM-5 (HZSM-5) zeolites as catalysts. The reaction was observed in the gas phase in the temperature interval from 407 to 480 K. The reaction products on both catalysts were ethene and water, whose concentration during the reaction was not observed. In the observed temperature interval the reaction of dehydration is not of the first rank, it has the initial period and gets sped up in time. By the increase of temperature the initial period gradually disappears and the reaction gets transferred to the first rank reaction on HM (at T=473 K), while on HZSM-5 zeolite at all observed temperatures the reaction has its initial period. Based on the obtained kinetic parameters it was determined that HM demonstrated a bigger catalytic activity for the diethyl ether dehydration reaction than it was the case with HZSM-5 zeolite. The adsorption of diethyl ether from the gas phase on HM and HZSM-5 zeolite at T=300 K provided an insight into the hydrophilic-hydrophobic characteristics of the surface, but also an insight into the character and intensity of the active centers of these zeolites. The obtained adsorption isotherms of diethyl ether on both zeolites are of a „mixed“ character and represent a combination of adsorption isotherms of Type III and Type V (in accordance with IUPAC classification), which indicated that both the inner and outer surface of these zeolites are to a certain degree hydrophobic. The adsorption isotherms of Type III (Type V) are characteristic of a weak adsorbent-adsorbate interaction. Since the diethyl ether molecule is to a certain extent polar, and since it prefers more acid active centers for adsorption, we can say based on the quantity of adsorbed diethyl ether on both zeolites that HM possesses a bigger number of acid active centers than HZSM-5 zeolite, while HZSM-5 zeolite possesses more acid (of a stronger acidity) active centers than HM. The obtained adsorption data are in accordance with the obtained kinetic data.

Key words:
dehydration, diethyl ether, mordenite, ZSM-5 zeolite, adsorption

Thematic field:
SYMPOSIUM A - Science of matter, condensed matter and physics of solid states

Date of abstract submission:
13.06.2015.

Conference:
Contemporary Materials 2015 - Savremeni Materijali

Abstract