Sulfated nanozirconia: an investigation on acid-base properties and n-butane isomerization activity.
Hydrated zirconia was synthesized by an organo-inorganic route employing surfactant and was sulfated using aqueous ammonium persulfate, followed by drying at 110 degrees C. The sample thus obtained was calcined at 600 degrees C to obtain sulfated zirconia and was characterized by several physicochemical methods. Crystallite sizes of sulfated zirconia were calculated from X-ray line broadening using the Debye-Scherer equation and were found to be in the range of 25 nm. When pretreated in air, the catalyst was found to exhibit butane isomerization activity at a temperature as low as 35 degrees C under atmospheric pressure. It showed conversion as high as 37% at 100 degrees C under normal pressure when pretreated in air, whereas nitrogen-pretreated catalyst showed zero activity under similar conditions. NH(3) and CO(2) temperature-programmed desorption studies on air- and helium-pretreated samples indicated that the catalyst surface changes appreciably during air pretreatment. Results on butane isomerization in conjunction with TPD studies suggest that zirconium-oxy sites play an important role in butane activation during the reaction.
Mishra
H K
HK
Catalysis and Chemical Reaction Engineering Laboratories, Department of Chemical Engineering, University of Saskatchewan, 105 Maintenance Road, S7N 5C5 Saskatoon, Canada.
Dalai
A K
AK
Das
D D
DD
Parida
K M
KM
Pradhan
N C
NC
D002073:Butanes / Q000737:chemistry*; D007536:Isomerism; D016062:Porosity; D013431:Sulfates / Q000138:chemical synthesis / Q000737:chemistry*; D013499:Surface Properties; D013696:Temperature; D015040:Zirconium / Q000737:chemistry*
D002073:Butanes; D013431:Sulfates; C046888:butane; D015040:Zirconium; C028541:zirconium oxide