80717-22-2Relevant articles and documents
Understanding the mechanism of N coordination on framework Ti of Ti-BEA zeolite and its promoting effect on alkene epoxidation reaction
Liang, Xiaohang,Liu, Dan,Luo, Yibin,Peng, Xinxin,Shu, Xingtian,Xia, Changjiu
, (2021/07/31)
The function of ammonium salts on the epoxidation performance over Ti-BEA zeolite was investigated in detail. Experiments of alkene epoxidation, side reactions of epoxide and decomposition of H2O2 with or without ammonium salts were designed, and the UV-Vis spectroscopy was employed to analyze the structure of Ti-hydroperoxo species. It is revealed that the ammonia (or amines) dissociated from the ammonium salt would chelate with the linear Ti-η1(OOH) species and form a bridged Ti-η2(OOH)-R species, which is more stable, more weaker in epoxide adsorption and acidity as well. Therefore, side reactions and H2O2 decomposition would be suppressed, and both alkene conversion and epoxide selectivity would be promoted simultaneously. On the other hand, the excessive NH3?H2O (NH3/Ti>1) or NaOH bond with the Ti-η2(OOH)-R species and generate salt-like Ti-η2(OO)-M+ species, resulting in the deactivation of Ti active center. While for ammonium salts, e.g. NH4Cl, the limited dissociation degree along with the acidic environment help the Ti active center to maintain in highly active. In short, this work provides a practical Ti active center tuning method for Ti-BEA zeolite, as well as a thorough understanding of its Ti-hydroperoxo species.
Synthesis of a silicalite-1-coated titanium silicalite-1 (TS-1) zeolite and its catalytic activity in liquid-phase oxidation
Sugiura, Yusuke,Hirota, Yuichiro,Uchida, Yoshiaki,Nishiyama, Norikazu
supporting information, p. 477 - 479 (2015/05/27)
Silicalite-1/titanium silicalite-1 (TS-1) composites were synthesized by growing silicalite-1 on the surface of TS-1. Oxidation of 1-hexene was studied using both the silicalite-1/TS-1 composite and uncoated TS-1. The silicalite-1/TS-1 composite showed a higher selectivity toward 1,2-epoxyhexane than uncoated TS-1 because sequential reactions on the external surface of TS-1 were inhibited. The catalytic activity of the silicalite-1/TS-1 composite was almost the same as that of TS-1, suggesting that the silicalite-1 layer is very thin and that the diffusion resistance is negligibly small.
Cyclopentadienyl and pentamethylcyclopentadienyl ruthenium complexes as catalysts for the total deoxygenation of 1,2-hexanediol and glycerol
Thibault, Michelle E.,Dimondo, Domenico V.,Jennings, Michael,Abdelnur, Patricia Verardi,Eberlin, Marcos N.,Schlaf, Marcel
supporting information; experimental part, p. 357 - 366 (2011/04/18)
The ruthenium aqua complexes [cp*Ru(OH2)(N-N)](OTf) (cp* = η5-pentamethylcyclopentadienyl, N-N = 2,2′-bipyridine, phen = 1,10-phenanthroline, OTf- = trifluoromethanesulfonate) and the acetonitrile complex [cpRu(CH 3CN)(bipy)](OTf) (cp = η5-cyclopentadienyl) are water-, acid-, and thermally stable (>200°C) catalysts for the hydrogenation of aldehydes and ketones in sulfolane solution. In the presence of HOTf as a co-catalyst, they effect the deoxygenation of 1,2-hexanediol to 1-hexanol and hexane. Glycerol is deoxygenated to 1-propanol in up to 18% yield and under more forcing conditions completely deoxygenated to propene. The structure of the acetonitrile pro-catalyst [cpRu(CH3CN)(bipy)](OTf) has been determined by X-ray crystallography (space group P1 (a = 9.3778(10) A; b = 10.7852(10) A; c = 11.1818(13) A; α = 101.718(5)°; β = 114.717(4)°; γ = 102.712(5)°; R = 3.95%).
