Organically Modified Titanium-Rich Ti-MCM-41, Efficient Catalysts for Epoxidation Reactions
Highly ordered, titanium-rich organically modified Ti-MCM-41 materials have been synthesized at 413 K using a mixture of organo-triethoxysilane and tetraethyl orthosilicate. Various organic substituents on Ti-MCM-41 used in the present study are methyl, vinyl, allyl, 3-chloropropyl, pentyl, and phenyl. The highest amount of Ti incorporated for a given Si/Ti mole ratio of 30 in the synthesis gel was 33.6 in the case of the 3-chloropropyl group. For methyl, vinyl, allyl, pentyl, and phenyl this ratio varied from 42 to 53, which is considerably lower than for unmodified Ti-MCM-41 reported earlier. Whereas incorporation of short chain organic functionality (C1–C3) causes an increase in the d spacing, resulting in wider pore openings, long chain (pentyl) and aromatic (phenyl) substituents cause a decrease in d spacing in these mesoporous molecular sieves. An increase in the organic content in the synthesis gel beyond a certain level also causes a decrease in d spacing. N2 and H2O adsorption studies revealed that these organically modified well ordered Ti-MCM-41 materials are more hydrophobic than that synthesized in the absence of organic modifiers. These organically modified Ti-MCM-41 materials are efficient catalysts in the epoxidation reaction of unsaturated alcohols followed by cyclization to cyclic ethers using TBHP as oxidant.
Share
Medical research
Medical
Fleming Research Institute of Life Sciences will...
