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279
highest conversion of phenol was obtained over TS-1-TPAOH-6-48,
due to the smallest crystal size, the higher crystallinity and larger
surface area. The smallest crystal size of TS-1-TPAOH-6-48 also led
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3.3. Different modification time of TPAOH
The cyclohexane adsorption curves of the six samples are almost
the same, except TS-1-TPAOH-6-24 (Fig. 5), and the saturation
adsorption amount of each sample is less than that of TS-1-Null,
due to the increasing crystal size.
The catalytic properties of phenol hydroxylation over small-
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With the increase of modification time, the conversion of phe-
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When the modification time increased, the amount of dissolution of
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Modification of small-crystal TS-1 with different organic bases
is a process of partly dissolution and partly recrystallization. Using
TPAOH to modify the TS-1, the recrystallization preferred to occur
a-oriented, while using TBAOH, it was b-oriented. TPA+ and TBA+
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The modification can improve the catalytic activity for the
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This work was financially supported by the program for New
Century Excellent Talent in University (Grant NCET-04-0268) and
the Plan 111 Project of the Ministry of Education of China. The
authors also thank Prof. Roel Prins for his thoughtful discussion.
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