Catalytic formation of acetic anhydride over tungstophosphoric acid modified SBA-15 mesoporous materials

Cited 68 time in Web of Science Cited 75 time in Scopus

He, Nong-Yue; Woo, Chang-Soo; Kim, Hyeon-Gook; Lee, Ho-In

Issue Date
Applied Catalysis A: General 281 (2005) 167–178
Tungstophosphoric acidMesoporous materialAcetic anhydrideImpregnationDirect synthesis
Tungstophosphoric acid H3PW12O40 (TPA) was impregnated on mesoporous materials SBA-15 with pore sizes 91.9 and 63.9 A ° at
different loadings. TPA-containing SBA-15 samples were synthesized with various TPA contents. The samples were characterized by means
of XRD, FTIR, TEM, ICP, and N2 adsorption. For the impregnated samples, TPA species was finely dispersed. TPA IR spectrum was not
detected for loading up to 1:5 (TPA:SBA-15, w:w) and became obvious with the increase in loading. The XRD diffraction peaks of HPAwere
not found for samples with loading up to 1:4 and were very weak for the samples with loading 2:3, while the TPA XRD diffraction peaks of
physical mixtures of TPA and mesoporous (1:10, w:w) were very strong. The chemically high-dispersed TPA species thus favored the
selectivity of acetic anhydride catalytically condensed from acetic acid at 823 K. The bigger the pore size, the better the selectivity. For the
directly synthesized TPA-containing samples, the chemically bound TPA species remained after hot water extraction at 373 K for 3 h. The
selectivity of acetic anhydride was further increased to 96% over the TPA-containing sample with 6.37 wt.% of chemically bound TPA
species, regardless of the smaller pore size (30.4 A ° ) compared to those of the TPA-impregnated samples, but the activity was decreased at low
TPA content ( 3.37 wt.%). Generally, results revealed that the finely dispersed and chemically bound TPA species and pore size were
responsible for the enhanced selectivity in our systems, bigger pore size favored both the activity and selectivity over samples with TPA
loading 5 wt.%, while the pure bulk TPA showed no selectivity for acetic anhydride under investigation.
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College of Engineering/Engineering Practice School (공과대학/대학원)Dept. of Chemical and Biological Engineering (화학생물공학부)Journal Papers (저널논문_화학생물공학부)
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