M. Hartmann et C. Bischof, Mechanical stability of mesoporous molecular sieve MCM-48 studied by adsorption of benzene, n-heptane, and cyclohexane, J PHYS CH B, 103(30), 1999, pp. 6230-6235
The synthesis of MCM-48 has been performed in a 5 L autoclave, and the prog
ress of the synthesis has been monitored by X-ray powder diffraction and Si
-29 MAS NMR. The formation of MCM-48 progresses via an intermediate phase,
whose conversion into the cubic phase is triggered by condensation of the s
ilanol groups. The mechanical stability of silica mesoporous material MCM-4
8 has been investigated employing powder X-ray diffraction, nitrogen adsorp
tion, and subcritical organic vapor (benzene, n-heptane, and cyclohexane) a
dsorption isotherms and breakthrough curves. The adsorption capacity is aff
ected considerably by mechanical compression between 20 and 400 N mm(-2), w
hile the material is destroyed to a large extend at 480 and 600 N mm(-2), w
hich is reflected by a dramatic decrease in adsorption capacity and poor X-
ray diffraction patterns. As a result of its three-dimensional structure, t
he mechanical stability of MCM-48 is larger compared to that of MCM-41 but
still low compared to that of crystalline structures such as zeolites.