\"The catalyzed partial oxidation of ethylene using oxygen was studied. Six silver-based catalysts were prepared, and the effects of BaCO3 and BaO2 as moderators were investigated. Silver components of the catalysts were either AgO or Ag2CO3.
The catalysts were characterized before and after exposure to reaction conditions using scanning electron microscopy, Auger electron emission spectroscopy and X-ray spectroscopy. Thermal and elemental analyses of the unconditioned bulk catalysts were also obtained.
The activities of the six catalysts were compared using a flow reactor system. Reactor temperatures were varied from 180°C to 320°C with inlet gas compositions of oxygen/ethylene of 50/50, 70/30 and 90/10 mole percent, respectively.
Conditioning of the catalysts prior to reaction caused the silver compound to be reduced to metallic silver. The conditioning and reaction periods also caused all the catalysts to sinter which resulted in a reduction of catalyst surface area. The barium additives reduced the extent of sintering, especially in the case of the catalysts prepared by coprecipitation. Octanol, used in the catalyst preparation step as a mulling agent, reacted with and altered the unconditioned AgO catalysts. However, the conditioning procedure removed the octanol reaction residue.
The barium additives stabilize the silver surface allowing the catalyst to retain higher activity due to higher surface area. There was no evidence of a high surface area barium carbonate film covering the modified catalysts\"--Abstract, page ii.
","abstract_html":"<p>"The catalyzed partial oxidation of ethylene using oxygen was studied. Six silver-based catalysts were prepared, and the effects of BaCO<sub>3</sub> and BaO<sub>2</sub> as moderators were investigated. Silver components of the catalysts were either AgO or Ag<sub>2</sub>CO<sub>3</sub>.</p> <p>The catalysts were characterized before and after exposure to reaction conditions using scanning electron microscopy, Auger electron emission spectroscopy and X-ray spectroscopy. Thermal and elemental analyses of the unconditioned bulk catalysts were also obtained.</p> <p>The activities of the six catalysts were compared using a flow reactor system. Reactor temperatures were varied from 180°C to 320°C with inlet gas compositions of oxygen/ethylene of 50/50, 70/30 and 90/10 mole percent, respectively.</p> <p>Conditioning of the catalysts prior to reaction caused the silver compound to be reduced to metallic silver. The conditioning and reaction periods also caused all the catalysts to sinter which resulted in a reduction of catalyst surface area. The barium additives reduced the extent of sintering, especially in the case of the catalysts prepared by coprecipitation. Octanol, used in the catalyst preparation step as a mulling agent, reacted with and altered the unconditioned AgO catalysts. However, the conditioning procedure removed the octanol reaction residue.</p> <p>The barium additives stabilize the silver surface allowing the catalyst to retain higher activity due to higher surface area. There was no evidence of a high surface area barium carbonate film covering the modified catalysts"--Abstract, page ii.</p>","abstract_has_math":false,"creators":["Pahl, Robert Harold"],"institution":"University of Missouri--Rolla","degree_name":"Ph. D. in Chemical Engineering","degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2016,"date_issued":"2016-02-10T08:00:00Z","date_published":"2016-02-10T08:00:00Z","updated_at":"2026-07-24T03:20:12Z","subjects":["Chemical Engineering"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":"https://scholarsmine.mst.edu/doctoral_dissertations/275","outbound_label":"Repository record","outbound_source":"dc:identifier"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Pahl, Robert Harold"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.available","label":"Dc Date Available","values":["2016-02-10T08:00:00Z"]},{"key":"dc:type","label":"Dc Type","values":["Dissertation - Restricted Access"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Ph. D. in Chemical Engineering"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["University of Missouri--Rolla"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Chemical Engineering"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier","label":"Identifier","values":["https://scholarsmine.mst.edu/doctoral_dissertations/275"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["\"The catalyzed partial oxidation of ethylene using oxygen was studied. Six silver-based catalysts were prepared, and the effects of BaCO3 and BaO2 as moderators were investigated. Silver components of the catalysts were either AgO or Ag2CO3.
The catalysts were characterized before and after exposure to reaction conditions using scanning electron microscopy, Auger electron emission spectroscopy and X-ray spectroscopy. Thermal and elemental analyses of the unconditioned bulk catalysts were also obtained.
The activities of the six catalysts were compared using a flow reactor system. Reactor temperatures were varied from 180°C to 320°C with inlet gas compositions of oxygen/ethylene of 50/50, 70/30 and 90/10 mole percent, respectively.
Conditioning of the catalysts prior to reaction caused the silver compound to be reduced to metallic silver. The conditioning and reaction periods also caused all the catalysts to sinter which resulted in a reduction of catalyst surface area. The barium additives reduced the extent of sintering, especially in the case of the catalysts prepared by coprecipitation. Octanol, used in the catalyst preparation step as a mulling agent, reacted with and altered the unconditioned AgO catalysts. However, the conditioning procedure removed the octanol reaction residue.
The barium additives stabilize the silver surface allowing the catalyst to retain higher activity due to higher surface area. There was no evidence of a high surface area barium carbonate film covering the modified catalysts\"--Abstract, page ii.
"]},{"key":"dc:title","label":"Title","values":["A characterization and study of barium promoted silver catalysts for the partial oxidation of ethylene"]}]}],"canonical_facts":{"dc:creator":["Pahl, Robert Harold"],"dc:date.available":["2016-02-10T08:00:00Z"],"dc:description.abstract":["\"The catalyzed partial oxidation of ethylene using oxygen was studied. Six silver-based catalysts were prepared, and the effects of BaCO3 and BaO2 as moderators were investigated. Silver components of the catalysts were either AgO or Ag2CO3.
The catalysts were characterized before and after exposure to reaction conditions using scanning electron microscopy, Auger electron emission spectroscopy and X-ray spectroscopy. Thermal and elemental analyses of the unconditioned bulk catalysts were also obtained.
The activities of the six catalysts were compared using a flow reactor system. Reactor temperatures were varied from 180°C to 320°C with inlet gas compositions of oxygen/ethylene of 50/50, 70/30 and 90/10 mole percent, respectively.
Conditioning of the catalysts prior to reaction caused the silver compound to be reduced to metallic silver. The conditioning and reaction periods also caused all the catalysts to sinter which resulted in a reduction of catalyst surface area. The barium additives reduced the extent of sintering, especially in the case of the catalysts prepared by coprecipitation. Octanol, used in the catalyst preparation step as a mulling agent, reacted with and altered the unconditioned AgO catalysts. However, the conditioning procedure removed the octanol reaction residue.
The barium additives stabilize the silver surface allowing the catalyst to retain higher activity due to higher surface area. There was no evidence of a high surface area barium carbonate film covering the modified catalysts\"--Abstract, page ii.
"],"dc:identifier":["https://scholarsmine.mst.edu/doctoral_dissertations/275"],"dc:subject":["Chemical Engineering"],"dc:title":["A characterization and study of barium promoted silver catalysts for the partial oxidation of ethylene"],"dc:type":["Dissertation - Restricted Access"],"thesis:degree_name":["Ph. D. in Chemical Engineering"],"thesis:institution_name":["University of Missouri--Rolla"]},"updated_at":"2026-07-24T03:20:12Z"}