p-Xylene-selective metal-organic frameworks: a case of topology-directed selectivity.
Para-disubstituted alkylaromatics such as p-xylene are preferentially adsorbed from an isomer mixture on three isostructural metal-organic frameworks: MIL-125(Ti) ([Ti(8)O(8)(OH)(4)(BDC)(6)]), MIL-125(Ti)-NH(2) ([Ti(8)O(8)(OH)(4)(BDC-NH(2))(6)]), and CAU-1(Al)-NH(2) ([Al(8)(OH)(4)(OCH(3))(8)(BDC-NH(2))(6)]) (BDC = 1,4-benzenedicarboxylate). Their unique structure contains octahedral cages, which can separate molecules on the basis of differences in packing and interaction with the pore walls, as well as smaller tetrahedral cages, which are capable of separating molecules by molecular sieving. These experimental data are in line with predictions by molecular simulations. Additional adsorption and microcalorimetric experiments provide insight in the complementary role of the two cage types in providing the para selectivity.
Centre for Surface Chemistry and Catalysis, Katholieke Universiteit Leuven, Arenbergpark 23, B-3001 Leuven, Belgium.
Frederik
F
Vermoortele
Michael
M
Maes
Peyman Z
PZ
Moghadam
Matthew J
MJ
Lennox
Florence
F
Ragon
Mohammed
M
Boulhout
Shyam
S
Biswas
Katrien G M
KG
Laurier
Isabelle
I
Beurroies
Renaud
R
Denoyel
Maarten
M
Roeffaers
Norbert
N
Stock
Tina
T
Düren
Christian
C
Serre
Dirk E
DE
De Vos