Silicalite batch compositions

Silicalite was synthesized from a batch composition of 2.55Na20-5.0TPABr-100Si02-2800H20... 

ABE production was studied by Qureshi et al [3.91] in a laboratory PVMBR system, which coupled a fed-batch fermentor (using C. acetobutylicum) with an UF membrane and a PV product recovery system using a silicalite-silicone composite membrane. Cells of C. acetobutylicum were removed from the culture using the 500,000 molecular weight... 

Qureshi, N., Meagher, M. M., Huang, J., Hutkins, R. W. (2001). Acetone butanol ethanol (ABE) recovery by pervaporation using silicalite-silicone composite membrane from fed-batch reactor of Clostridium acetobutylicum. Journal of Membrane Science, 187, 93-102. 

Table 2 shows data from several sources in which the individual linear crystal growth rates for Al-free ZSM-5, or silicalite, were reported. The temperatures used in each study were very similar, except in [31], and the linear growth rates also were quite similar, except in the case of one of the systems used in [22]. The differences in that work were attributed to different synthesis conditions compared to that in [7], most notably the higher pH of ca. 12.5 in [22] compared to 10.6-11.6 in [7]. The growth rates reported for silicalite in [25] were almost identical to those found in [7], in spite of the fact that ethanol was used in one study, but not the other. Due to the similarities of the batch compositions in [22] and [25], except for ethanol, one would expect that the growth rates might be similar rather than different by an order of magnitude. 

Batch oxide molar chemical composition of the reaction mixture (hydrogel) for the synthesis was 1.0 AI2O3/IOO Si02/28 Na20/4000 H2O. A series of silicalite-1 nanocrystals having different mean diameters (90, 180, 220, 260 and 690 nm Fig. 2) were prep>ared by synthesis from clear solution and used as seeds for the further growth of ZSM-5 nanocrystals. 

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