Influence of Brønsted acid ionic liquid structure on hydroxyacid polyesterification
摘要:
基于4-(3′-丁基-1′-咪唑鎓)-1-丁磺酸阳离子的Brønsted酸离子液体(BAILs)被发现是非常高效的不饱和聚酯溶剂和催化剂。仅在90–110 °C下5–30分钟就可以获得高摩尔质量的聚(12-羟基十二酸)(Mw高达40000 g mol−1)。在不饱和聚酯中含有双(三氟甲磺酰)亚胺阴离子(Tf2N)的BAILs中,不饱和聚酯化反应速度更快,但在最终聚合物中检测到少量由副反应产生的醚和双键。另一方面,在含有硫酸氢阴离子的BAILs中,除了形成磺酸酯中间体并进一步与羧酸基团反应生成预期的酯之外,没有发生副反应。这种中间体在基于Tf2N的BAILs中未被观察到,可能参与了保护羟基端基在基于硫酸氢的BAILs中免受醚化副反应的影响。为了解释这些BAILs的不同行为,并且由于H2SO4的酸性远高于Tf2NH,因此提出这些BAILs的结构可能不同:前者是烷基磺酸取代的咪唑鎓,而后者可能只是咪唑鎓-磺酸盐两性离子和Tf2NH的混合物。还讨论了反应温度、水的消除方法和BAIL浓度对不饱和聚酯化的影响。
The SO3H-tethered imidazolium and triazolium salts, nonvolatile and recyclable Brønstedacidicionicliquids, efficiently mediate intramolecular hydroalkoxylations of alkenyl alcohols. They have been successfully employed in the synthesis of (±)-centrolobine.
SO 3 H系咪唑鎓盐和三唑鎓盐,不挥发且可回收的布朗斯台德酸性离子液体,可有效介导链烯醇的分子内加氢烷氧基化反应。它们已成功地用于合成(±)-中心洛宾。
Selective palladium-catalysed arylation of 2,6-dibromopyridine using N-heterocyclic carbene ligands
作者:D. Prajapati、C. Schulzke、M. K. Kindermann、A. R. Kapdi
DOI:10.1039/c5ra10561g
日期:——
A selective palladium-catalysed arylation of 2,6-dibromopyridine has been developed by employing N-heterocyclic carbene ligands. Selective mono-arylation was performed in water/acetonitrile solvent system at ambient temperature with catalyst loading of 0.1 mol%. This reaction was also found to proceed smoothly in water although at a slightly elevated temperature of 80 °C. 2,6-Disubstituted and diversely
The carbon chain length of ILs has effect on its catalytic activity and [C6ImBS][HSO4]shows the best catalytic performance.
离子液体的碳链长度对其催化活性有影响,[C6ImBS][HSO4]表现出最佳的催化性能。
Improved solubilization of pyromellitic dianhydride and 4,4′-oxydianiline in ionic liquid by the addition of zwitterion and their polycondensation
作者:Masahiro Tamada、Takahiro Hayashi、Hiroyuki Ohno
DOI:10.1016/j.tetlet.2007.01.012
日期:2007.2
for polyimide synthesis. The solubility of 4,4′-oxydianiline and pyromelliticdianhydride as starting materials in ionic liquids was first evaluated, and then their polycondensation was carried out. Although these starting materials were hardly soluble in 1-benzyl-3-methylimidazolium bis(trifluoromethane sulfonyl)imide (3), addition of imidazolium type zwitterion, 1-(1-butyl-3-imidazolio)butane-4-sulfonate
制备了三种不同的离子液体,并将其用作聚酰亚胺合成的溶剂。首先评估了4,4'-羟基二苯胺和均苯四甲酸二酐在离子液体中的溶解度,然后进行了缩聚反应。尽管这些原料几乎不溶于1-苄基-3-甲基咪唑双(三氟甲烷磺酰基)酰亚胺(3),但添加咪唑类两性离子,1-(1-丁基-3-咪唑并)丁烷-4-磺酸酯(ZI) ,当然提高了它们的溶解度。当使用含有40mol%ZI的3时,冷却至室温后,没有从该包含两种原料的混合溶液中相分离。在3中制备预聚物后在室温下,在含有40mol%的ZI的情况下,在相同的溶液中于100、200,然后300℃下每1小时进行缩聚,从而得到聚酰亚胺。所获得的聚酰亚胺(在10ml浓硫酸中为0.05g)的固有粘度为1.3dL g -1,高于仅在3个中所制备的特性粘度(0.9dL g -1)。聚酰亚胺较高的平均分子量归因于原料的溶解度的提高,这是因为添加了ZI,从而可以在酰亚胺化前不加热的情况下制备预聚物聚(酰胺酸)。
Synthesis of 1‐Octanol and 1,1‐Dioctyl Ether from Biomass‐Derived Platform Chemicals
作者:Jennifer Julis、Walter Leitner
DOI:10.1002/anie.201203669
日期:2012.8.20
The happy medium: A new catalytic pathway for the synthesis of the linear primary C8 alcohol products 1‐octanol and dioctyl etherfrom furfural and acetone has been developed using retrosynthetic analysis. This opens a general strategy for the synthesis of medium‐chain‐length alcohols from carbohydrate feedstock.