A characterization and study of barium promoted silver catalysts for the partial oxidation of ethylene

Author

Robert Harold Pahl

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.

Advisor(s)

Mayhan, Kenneth G.

Committee Member(s)

Roach, D. Vincent
O'Keefe, T. J. (Thomas J.)
Crosser, Orrin K.
Bertrand, Gary L.
Levenson, L. L., 1928-1998

Department(s)

Chemical and Biochemical Engineering

Degree Name

Ph. D. in Chemical Engineering

Publisher

University of Missouri--Rolla

Publication Date

1974

Pagination

xiii, 166 pages

Note about bibliography

Includes bibliographical references (pages 125-126).

Rights

© 1974 Robert Harold Pahl, All rights reserved.

Document Type

Dissertation - Restricted Access

File Type

text

Language

English

Subject Headings

Ethylene -- oxidationSilver catalystsSurfaces -- Areas and volumes

Thesis Number

T 3045

Print OCLC #

6013392

Electronic OCLC #

913884674

Recommended Citation

Pahl, Robert Harold, "A characterization and study of barium promoted silver catalysts for the partial oxidation of ethylene" (1974). Doctoral Dissertations. 275.
https://scholarsmine.mst.edu/doctoral_dissertations/275