Alumina-supported Molybdenum (VI) Oxide: An Efficient and Recyclable Heterogeneous Catalyst for Regioselective Ring Opening of Epoxides with Thiols, Acetic Anhydride, and Alcohols under Solvent-free Conditions
作者:Sweety Singhal、Suman L. Jain、Bir Sain
DOI:10.1246/cl.2008.620
日期:2008.6.5
An efficient and simple protocol for regioselective ring opening of epoxides with thiols, aceticanhydride, and alcohols using 16 wt % MoO3 supported on alumina as a recyclable catalyst is described.
Understanding the mechanism of N coordination on framework Ti of Ti-BEA zeolite and its promoting effect on alkene epoxidation reaction
作者:Xiaohang Liang、Xinxin Peng、Dan Liu、Changjiu Xia、Yibin Luo、Xingtian Shu
DOI:10.1016/j.mcat.2021.111750
日期:2021.7
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
摘要 详细研究了铵盐对Ti-BEA沸石环氧化性能的影响。设计了有或没有铵盐的烯烃环氧化、环氧化物副反应和H2O2分解的实验,并采用紫外-可见光谱分析了钛氢过氧化物的结构。结果表明,从铵盐中解离出来的氨(或胺)会与线性 Ti-η1(OOH) 物种螯合,形成桥接 Ti-η2(OOH)-R 物种,在环氧化物中更稳定,更弱吸附和酸度也一样。因此,副反应和 H2O2 分解会被抑制,同时烯烃转化率和环氧化物选择性都会得到提高。另一方面,过量的 NH3•H2O (NH3/Ti> 1) 或 NaOH 与 Ti-η2(OOH)-R 物种键合,生成盐状 Ti-η2(OO)-M+ 物种,导致 Ti 活性中心失活。而对于铵盐,例如 NH4Cl,有限的解离度以及酸性环境有助于 Ti 活性中心保持高活性。总之,这项工作为 Ti-BEA 沸石提供了一种实用的 Ti 活性中心调谐方法,以及对其 Ti-hydroperoxo
Oligonucleotides having A-DNA form and B-DNA form conformational geometry
申请人:——
公开号:US20030096979A1
公开(公告)日:2003-05-22
Modified oligonucleotides containing both A-form conformation geometry and B-from conformation geometry nucleotides are disclosed. The B-form geometry allows the oligonucleotide to serve as substrates for RNase H when bound to a target nucleic acid strand. The A-form geometry imparts properties to the oligonucleotide that modulate binding affinity and nuclease resistance. By utilizing C2′ endo sugars or O4′ endo sugars, the B-form characteristics are imparted to a portion of the oligonucleotide. The A-form characteristics are imparted via use of either 2′-O-modified nucleotides that have 3′ endo geometries or use of end caps having particular nuclease stability or by use of both of these in conjunction with each other.
[EN] USE OF SUBSTITUTED OXADIAZOLES FOR COMBATING PHYTOPATHOGENIC FUNGI<br/>[FR] UTILISATION D'OXADIAZOLES SUBSTITUÉS POUR LUTTER CONTRE DES FONGUS PHYTOPATHOGÈNES
申请人:BASF SE
公开号:WO2015185485A1
公开(公告)日:2015-12-10
The present invention relates to the use of novel oxadiazoles of the formula I or an N- oxide and/or their agriculturally useful salts for controlling phytopathogenic fungi, or to a method for combating phytopathogenic harmful fungi, which process comprises treating the fungi or the materials, plants, the soil or seeds to be protected against fungal attack, with an effective amount of at least one compound of formula I or an N- oxide or an agriculturally acceptable salt thereof; and to agrochemical compositions comprising at least one such compound and to agrochemical compositions further comprising seeds.
Reaction-Controlled Phase-Transfer Catalytic Oxidative Cleavage of Cyclopentene to Glutaraldehyde over Peroxy-niobic Acid
作者:Hao Chen、Wei-Lin Dai、An-Ren Jiang、Jing-Fa Deng
DOI:10.1246/cl.2002.220
日期:2002.2
The oxidative cleavage of cyclopentene to glutaraldehyde with aqueous H2O2 was performed over a peroxy-niobic acid catalyst with high yield (72%) and complete conversion of cyclopentene under mild reaction conditions. Peroxy-niobic acid has been shown as a “reaction-controlled phase-transfer” catalyst, which has the advantages of both homogeneous and heterogeneous catalysts.