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Catalysis Research Center - Seminars

Preparation and Structures of Metal Anion “Cubes” in Zeolites. Implications for Application Including Catalysis

Chemistry Department, University of Hawaii

Lead easily forms Pb4O4 cubes (distorted cubes with tetrahedral symmetry) in the sodalite cavities of zeolite X upon ion exchange with Pb2+ and vacuum dehydration at ca. 400 oC.  Similarly La3+ and water form La4O4 cubes laced together at each La3+ corner by an oxide ion, leaving many H+ ions free for acid catalysis, which is important to the petrochemical industry.  Cd6S44+ cations with Cd4S4 cores have been prepared in zeolite A, as have the photosensitive Ag4X4 clusters (X = Cl-, Br-, I-).  Ni8O48+ clusters with Ni4O4 cores have been found in zeolite Y, together with three-coordinate Ni2+.  Ni-Y is effective in the oxidation of NOx and both the hydrogenation and oxidation of CO.  Cubic clusters of In4(OH)48+ in zeolite Y may participate directly in catalysis by donating H+ ions and accepting them back later in a catalytic cycle, and they may do the same with pairs of electrons, much like the Fe4S4 cubes in enzymes.  In zeolites, indium catalyzes alkylation and alkyl transfer in aromatics, the benzoylation of naphthalene, the conversion of methane to higher hydrocarbons, and the reduction of NOx by hydrocarbons at practical conditions.

 

Autobiosketches

 

KARL SEFF, a curriculum vitae

Chemistry Department, University of Hawaii

2545 The Mall, Honolulu, Hawaii  96822-2275

e-mail:  seff@hawaii.edu

B. Education

1.

U.C.

Berkeley

1955 to 1959

B.S.

6/59

Physical Chemistry

2.

M.I.T.

Cambridge,

Mass.

1959 to 1964

Ph.D. with

D.P. Shoemaker

9/64

Physical Chemistry

and crystallography

3.

M.I.T.

Cambridge,

Mass.

1964

Postdoctoral work

with D.P. Shoemaker

11/64

Zeolite powder

crystallography

4.

U.C.

Los Angeles

1965 to 1967

Postdoctoral work

with K.N. Trueblood

6/66

Single-crystal

crystallography

C.  Positions held

1.

7/66 - 1/68

Assistant Research Chemist

U.C.L.A.

Computer liaison

X-ray crystallography

2.

2/68 - 6/73

Assistant Professor

U. Hawaii

Chemical crystallography

3.

7/73 - 6/75

Associate Professor with tenure

U. Hawaii

Chemical crystallography

4.

10/74 - 2/75

Visiting Scholar

Princeton

Zeolite catalysis

5.

7/75 - 12/06

Professor

U. Hawaii

Chemical crystallography

6.

10/81 - 5/82

Associate Researcher

U. Mexico

Crystallography

7.

7/88 - 12/88

6/89 -12/89

Visiting Scholar

Oxford,UK

Zeolite crystallography

Rietveld refinement

8.

1/89 - 6/89

Visiting Professor

Dartmouth

Crystallography

9.

7/96 -12/96

Visiting Scholar

Korean Univs.

Zeolite crystallography

10.

1/00 - 6/00

Associate Chair, Chemistry

U. Hawaii

 

11.

12.

7/00 - 6/03

1/07 - present

Chair, Chemistry

Professor Emeritus

U. Hawaii

U. Hawaii

 

Zeolite chem. & crystallogr.

 

E. Membership in societies

  1. American Crystallographic Association, since 1962
  2. American Chemical Society, since 1972
  3. International Zeolite Association, since 1973

F. Theses by students working under my direction: 12 Ph.D. and 19 M.S.

G. 3 US Patents and over 240 publications

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