57794-08-8Relevant articles and documents
Enantiotopic Discrimination by Coordination-Desymmetrized meso-Ligands
Li, Yutang,Lidskog, Anna,Armengol-Relats, Helena,Pham, Thanh Huong,Favraud, Antoine,Nicolas, Maxime,Dawaigher, Sami,Xiao, Zeyun,Ma, Dayou,Lindb?ck, Emil,Strand, Daniel,W?rnmark, Kenneth
, p. 1575 - 1579 (2020/02/04)
The first examples of enantiopure catalysts that are chiral merely due to coordination of different metal ions at enantiotopic positions of an achiral meso-ligand are reported. These catalysts exhibit a pseudo-Cs symmetry and are able to catalyze reactions demanding simultaneous involvement of two catalytic sites. The latter was demonstrated by application in the asymmetric ring-opening of meso-epoxides.
Olefin reaction in the catalyst and the olefin production
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Paragraph 0147; 0149, (2020/10/31)
PROBLEM TO BE SOLVED: To provide a catalyst for obtaining an olefin in high selectivity with a vicinal diol as a raw material.SOLUTION: A catalyst for olefination reaction for use in a reaction to produce an olefin by a reaction of a polyol, having two adjacent carbon atoms each having a hydroxy group, with hydrogen comprises: a carrier; at least one oxide selected from the group consisting of oxides of the group 6 elements and oxides of the group 7 elements supported on the carrier; and at least one metal selected from the group consisting of silver, iridium, and gold supported on the carrier.SELECTED DRAWING: None
Epoxidation of cyclohexene with H2O2 over efficient water-tolerant heterogeneous catalysts composed of mono-substituted phosphotungstic acid on co-functionalized SBA-15
Jin, Manman,Niu, Qingtao,Guo, Zhenmei,Lv, Zhiguo
, (2019/07/31)
A series of Keggin-type heteropolyacid-based heterogeneous catalysts (Co-/Fe-/Cu-POM-octyl-NH3-SBA-15) were synthesized via immobilized transition metal mono- substituted phosphotungstic acids (Co-/Fe-/Cu-POM) on octyl-amino-co-functionalized mesoporous silica SBA-15 (octyl-NH2-SBA-15). Characterization results indicated that Co-/Fe-/Cu-POM units were highly dispersed in mesochannels of SBA-15, and both types of Br?nsted and Lewis acid sites existed in Co-/Fe-/Cu-POM-octyl-NH3-SBA-15 catalysts. Co-POM-octyl-NH3-SBA-15 catalyst showed excellent catalytic performance in H2O2-mediated cyclohexene epoxidation with 83.8% of cyclohexene conversion, 92.8% of cyclohexene oxide selectivity, and 98/2 of epoxidation/allylic oxidation selectivity. The order of catalytic activity was Co-POM-octyl-NH3-SBA-15?>?Fe-POM-octyl-NH3-SBA-15?>?Cu-POM-octyl-NH3-SBA-15. In order to obtain insights into the role of -octyl moieties during catalysis, an octyl-free catalyst (Co-POM-NH3-SBA-15) was also synthesized. In comparison with Co-POM-NH3-SBA-15, Co-POM-octyl-NH3-SBA-15 showed enhanced catalytic properties (viz. activity and selectivity) in cyclohexene epoxidation. Strong chemical bonding between -NH3 + anchored on the surface of SBA-15 and heteropolyanions resulted in excellent stability of Co-POM-octyl-NH3-SBA-15 catalyst, and it could be reused six times without considerable loss of activity.