2011年3月3日 · Niobic acid, Nb2O5·nH2O, has been studied as a heterogeneous Lewis acid catalyst. NbO4 tetrahedra, Lewis acid sites, on Nb2O5·nH2O surface immediately form NbO4−H2O adducts in the presence of water...

铌酸为氧化铌的水合物, 分子式为Nb₂O₅·nH₂O 。 铌酸或Nb₂O₅可通过铌的氯化物或醇盐水解制得。 铌酸在工业上是由碱法或酸法从铌铁矿和钽铁矿Fe [ (Nb , Ta)O3] 2 中制得的。例如, 酸法是将粉末状的矿物与硫酸氢钾共熔, 然后用水洗涤熔体, 并用盐酸除去铁等, 最后将熔体置于浓硫酸中煮沸, 钽酸仍留在熔体中, 铌酸则在溶液中;实验室一般是由可溶性铌 (Nb)化合物水解或由碱性铌酸盐酸化制得。 铌酸是一种独特的 固体催化剂。 较低温度加热时 (373~573 K), 铌酸酸强度颇高 (H0 = …

2011年3月30日 · Niobic acid, Nb (2)O (5)·nH (2)O, has been studied as a heterogeneous Lewis acid catalyst. NbO (4) tetrahedra, Lewis acid sites, on Nb (2)O (5)·nH (2)O surface immediately form NbO (4)-H (2)O adducts in the presence of water.

原料为：水合五氧化二铌(Nb2O5•nH2O，通常称铌酸)。不知道它能溶于什么溶液？溶液pH对它的影响如何？是不是碱性条件下就形成了沉淀？ 谢谢了解的解答。 [Last edited by linweiguo0 on 2007-6-6 at 08:57 ] 返回小木虫查看更多

2011年3月30日 · 铌酸，Nb (2)O (5)·nH (2)O，已被研究作为非均相路易斯酸催化剂。 NbO (4) 四面体、Lewis 酸位点，在 Nb (2)O (5)·nH (2)O 表面上立即形成 NbO (4)-H (2)O 加合物在水的存在下。 然而，部分加合物仍然可以作为有效的路易斯酸位点，催化苯甲醛与四烯丙基锡的烯丙基化以及葡萄糖在水中转化为 5-（羟甲基）糠醛。 Niobic acid, Nb (2)O (5)·nH (2)O, has been studied as a heterogeneous Lewis acid catalyst.

2009年8月31日 · Hydrated niobium oxide (niobic acid) was effectively supported on mesoporous silica SBA-15 by HCl treatment of colloidal niobium oxide solution. The obtained Nb/SBA-15 exhibited high thermal stability, with no crystallization of niobium oxide. The number of generated Brönsted and Lewis acid sites increased with the Nb 2 O 5 content.

Nb2O5·nH2O 表面即使在空气中加热 100 °C 后仍表现出强酸性（H0≤-5.6），但在更高温度下热处理时强酸位点消失。 根据吸附吡啶的 IR 研究，在中等温度下热处理的催化剂上的活性位点主要归因于布朗斯台德酸位点。

2010年2月1日 · Hydrous niobium oxide (Nb 2 O 5 · n H 2 O) nanoparticles had been successfully prepared by water-in-oil microemulsion.

2010年5月7日 · Mesoporous Nb2O5·nH2O was prepared using amphiphilic block copolymers (L64, P103, and P123) that acted as structure-directing agents. Mesoporous Nb2O5·nH2O exhibits much higher catalytic activity f...

2011年3月1日 · Nb2O5 showed outstanding potential as a catalyst support for FPO-LP HDO, taking into account the improved properties of the upgraded oil, such as higher carbon content and lower water and oxygen...