Gryn S. Structure and catalytic properties of the mesoporous molecular sieves with siloxytitanate and ethylenephenylene groups in the silica framework.

The properties of the titanosiliceous and organosiliceous mesoporous molecular sieves (MMS) synthesized by the template-directed method using the frame-forming substances which act as the structural building blocks are considered. The using of the tert-butoxy siloxytitanate (the general formula is Ti(O-Si(O-t-C4H9)3)x(OR)4-x ; х=2 or 3, R=C3H7, і-C3H7 or -C4H9) leads to the formation of ordered titanosiliceous MMS with high content of TiO2 (up to 27 % mol.), large surface area (270 - 730 m2/g) and pore volume (0,3 - 0,77 сm3/g) as well as narrow pore size distribution (D = 2,4 - 2,8 nm). It was shown that Ti atoms are uniformly distributed in the SiO2 matrix as tetrahedral and octahedral titan-oxide sites as well as small titania clusters. These properties resulted in higher catalytic activity in the oxidation of benzene with Н2О2 as compared to Ti-МСМ-41 obtained by co-precipitation method. It was shown that the use of the TS-1 zeoilite nanoparticles (in the form of sol) as building blocks for the synthesis of MMSs allows an introduction of "zeolite-type" micropores with diameter ~1 nm and with pore volume up to 0,1 сm3/g into the MCM-41 structure. Resulted TS-1/MCM-41 materials are more efficient catalysts of the cyclohexane oxidation by Н2О2 than TiSi-МСМ-41. The incorporation of 1,5-bis-(2'-ethyl)-2,4-diethylphenilene bridging groups allows to obtain the organosilicas with large surface area (up to 600 m2/g), hexagonal-ordered mesopores (D = 2,5 - 4 nm), larger secondary pores (D = 8 - 17 nm), high pore volume (up to 1,7 сm3/g) and low density (0,10 - 0,15 g/сm3). The sulfonation of aforementioned samples resulted in MMS with arylsulfonic acid groups, which exceeds other tested organosulfonic silicas as catalysts of ethyl-tert-butyl ether synthesis from isobutylene and ethanol.