US EPA

1494726 

Journal Article 

HIGH-PRESSURE HYDROGENATION OF NAPHTHALENE USING A REDUCED IRON CATALYST 

Zhan, XD; Guin, JA 

1994 

Yes 

Energy and Fuels
ISSN: 0887-0624
EISSN: 1520-5029 

8 

6 

1384-1393 

English 

10.1021/ef00048a030 

WOS:A1994PR94000031 

http://://WOS:A1994PR94000031
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Based upon the interest in iron as a potential dispersed
phase catalyst for synfuels production, the high-pressure hydrogenation of naphthalene in mineral
oil and cyclohexane solvents was studied in trickle flow and vapor-phase reactors, respectively,
with an unsupported iron oxide powder as catalyst. Several forms of iron catalyst were examined
including the original iron oxide, hydrogen prereduced, and in-situ sulfided forms. A commercial
Ni-Mo/Al2O3 catalyst was used for comparison. Iron oxide was not active for hydrogenation;
however, in situ reduction by hydrogen yielded a remarkably active hydrogenation catalyst. The
secondary hydrogenation reaction to form decalins from tetralin occurred only with the hydrogen
reduced iron. Kinetic behavior was determined in the vapor phase at 6.9 MPa and at temperatures
over a range of 160-300 degrees C. Trickle bed experiments showed the iron oxide catalyst to be
much more rapidly deactivated than the baseline NiMo/Al2O3. In vapor-phase operation using
reduced iron as catalyst, rapid deactivation occurred with a 2.0 wt % naphthalene feed, whereas
little deactivation was found with a 0.2% feed. Transport limitations found with NiMo/Al2O3
catalyst extrudates were consistent with estimated effectiveness factors, and were eliminated by
crushing the extrudates to 40-50 mesh. Sulfur rapidly poisoned the hydrogenation function of the
iron catalyst with the order of decreasing activity being Fe much greater than FeSx or Fe2O3. A
proposed Langmuir-Hinshelwood rate expression, which reduced to a first-order dependence on both
naphthalene and hydrogen, was found to satisfactorily fit the data. Although the reduced iron
catalyst exhibited high hydrogenation activity under certain conditions, its propensity toward
deactivation and poisoning would limit its application in direct coal liquefaction.