Y. Liu et al. / Journal of Catalysis 225 (2004) 381–387
387
Although the rates of alkylation are slower over 2% Al-HMS
and 2% Al-MSU-G, resulting in DCDPA yields of 71.3 and
73.7% after 6.0 h reaction times, the AMS dimerization rates
for these catalysts also are lower. Thus, increasing the re-
action time over these latter catalysts to 24 h boosts the
yields of DCDPA to values of 90.1 and 91.3% (cf. Table 2).
Thus, the mesostructure-supportedH3PW12O40 catalysts are
substantially less selective alkylation catalysts than the cor-
responding aluminated mesostructures. It appears that the
high acid strength of the supported H3PW12O40 catalysts,
which compromises the alkylation of both DPA and MCDPA
through AMS dimerization, causes the catalytic properties to
be similar to those of the strong acid F-20 clay catalyst.
parison to the commercial F-20 clay catalyst by being less
prone to the masking of acidity through the adsorption of
reaction products.
Acknowledgment
The support of this research by the National Science
Foundation through CRG Grant CHE-0211029 is gratefully
acknowledged.
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