TY - GEN
T1 - Environmental friendly and highly regioselective oxybromination in an aqueous system using SBA-15 supported sulfated zirconia catalyst
AU - Chen, Ai Jan
AU - Chen, Xiao Rong
AU - Mou, Chung Yuan
PY - 2010
Y1 - 2010
N2 - Brominated aromatic compounds have been widely used in synthetic organic chemistry for the manufacturing of many bulk and fine chemicals. In contrast to direct bromination by toxic elemental bromine or HBr, we developed a safe system for oxybromination using hydrogen peroxide and ammonium bromide in the aqueous phase under mild temperature and near neutral conditions over a SBA-15 supported sulfated zirconia (SZ) catalyst. The ready availability of the catalyst and the nearly neutral aqueous solution are the salutary features of this approach. Bromination of aromatics with electron-withdrawing group took place readily, and bromoproducts were produced in moderate to excellent yields. A good to excellent para-selectivity was observed. The SZ/SBA-15 catalyst may be re-used several times without substantial loss of activity. We also studied the catalytic activity of SZ which were supported on mesoporous SBA-15 silica or mesoporous SZ. On bromination silica supported sulfated zirconia (SZ/SBA-15) showed much better catalytic ability for bromination then self-supported SZ (m-SZ). Furthermore, we found the catalytic activity of SZ decreased as the calcinations temperature increased. The good catalytic performance of the SZ/SBA-15 materials was attributed to the well dispersed of sulfate groups to give sulfated silica-zirconia of with (1) very good redox property and (2) high strength and high density of acid sites.
AB - Brominated aromatic compounds have been widely used in synthetic organic chemistry for the manufacturing of many bulk and fine chemicals. In contrast to direct bromination by toxic elemental bromine or HBr, we developed a safe system for oxybromination using hydrogen peroxide and ammonium bromide in the aqueous phase under mild temperature and near neutral conditions over a SBA-15 supported sulfated zirconia (SZ) catalyst. The ready availability of the catalyst and the nearly neutral aqueous solution are the salutary features of this approach. Bromination of aromatics with electron-withdrawing group took place readily, and bromoproducts were produced in moderate to excellent yields. A good to excellent para-selectivity was observed. The SZ/SBA-15 catalyst may be re-used several times without substantial loss of activity. We also studied the catalytic activity of SZ which were supported on mesoporous SBA-15 silica or mesoporous SZ. On bromination silica supported sulfated zirconia (SZ/SBA-15) showed much better catalytic ability for bromination then self-supported SZ (m-SZ). Furthermore, we found the catalytic activity of SZ decreased as the calcinations temperature increased. The good catalytic performance of the SZ/SBA-15 materials was attributed to the well dispersed of sulfate groups to give sulfated silica-zirconia of with (1) very good redox property and (2) high strength and high density of acid sites.
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M3 - Conference contribution
AN - SCOPUS:77956109296
SN - 9781605111902
T3 - Materials Research Society Symposium Proceedings
SP - 107
EP - 112
BT - Catalytic Materials for Energy, Green Processes and Nanotechnology
T2 - 2009 MRS Fall Meeting
Y2 - 30 November 2009 through 3 December 2009
ER -