【作者】 王欣；

【导师】 顾彦龙；

【作者基本信息】 华中科技大学 ， 物理化学， 2020， 硕士

【摘要】 低共熔溶剂(DES)是一种类离子液体,由氢键给体和氢键受体混合而成。由于其制备简单、廉价易得、组成可调,可作为溶剂应用于有机反应和萃取分离中。低共熔溶剂通常呈中性或弱碱性。尽管很多酸催化剂广泛用于有机合成中,寻找一种新的绿色酸催化剂仍然是绿色化学和催化化学的难点。目前,强酸性低共熔溶剂的研究报道很少。本论文制备了一种强酸性低共熔溶剂,并以其为催化剂考察了多种有机转化反应,获得了良好的应用效果。在反应模型一中,强酸性DES可重复使用多次而没有明显的催化活性的下降;在反应模型二中,DES重复使用五次活性降低约10%,可能是由于循环过程中DES有一定的物理损失。为了了解DES催化剂的物理化学性质,借助光谱学手段对该类DES催化剂进行了表征。红外光谱研究发现,该类DES相比于PEG4000及PTSA体系具有更强的氢键。TGA研究发现,该类强酸性DES在200°C以下具有良好的热力学稳定性。该强酸性DES本文中被应用在以下三个有机转化反应中:1.水杨醛、苯乙烯和小分子醇之间的三组分反应。在PEG4000/PTSA的催化作用下,该反应可以以中等到良好的产率得到3,4-二氢苯并吡喃类化合物。2.肉桂酸与苯酚之间的缩合环化反应。在PEG4000/PTSA的催化作用下,上述原料可被高效地转化为二氢香豆素类化合物。3.吲哚和1,2-邻二酮之间的缩合环化制备吲哚并咔唑类化合物。该论文工作不但发展了一类新型的强酸性DES均相催化体系,也实现了部分酸催化转化反应的绿色化。更多还原

【Abstract】 Deep eutectic solvent(DES)is a kind of solvent similar to ionic liquid,which is composed normally of a hydrogen bond donor and a hydrogen bond acceptor.Because of its simple preparation procedure,low cost and tunable composition and properties,they can usually be used as a new generation of green solvent for organic synthesis and separations.Deep eutectic solvent is usually neutral or weak alkaline.Although acidic catalysts have been widely used in organic synthesis,and searching for new and green alternative acid catalysts is also hard task of green and catalytic chemists.Until now,little attention has been paid to strongly acidic DES.In this thesis,a kind of strongly acidic DES was developed,which was then used as a catalyst in some organic transformations.The DES catalyst can be recycled and reused at least for five times with only little decrease of its catalytic activity in the first reaction,and in the second reaction,the activity of DES decreased about 10% which may d ue to the loss of DES in the transformation.Meanwhile,the DES catalyst was also characterized by FT-IR and TGA.And FT-IR investigation showed that hydrogen bond was indeed formed in the DES system composed of PTSA and PEG4000.TGA study revealed that the acidic DES is quite stable,and no decomposition was observed below 200 °C.The strongly acidic DES was examined in the following three organic transformations:1.Three-component reaction of salicylaldehyde,styrene and light alcohol.With the aid of the PEG4000/PTSA DES system,and 3,4-dihydrobenzopyran can be obtained in moderate to good yield.This reaction has not been reported before.2.Condensation of cinnamic acid and phenol to form coumarin.PEG4000/PTSA was proven to be an effective and recyclable catalyst for this transformation.3.Indole to carbazole transformation by using 2-arylindole and 1,2-diketone as starting materials.This paper not only develops a new type of homogeneous catalytic system of strongly acidic DES,but also realizes the green transformation of partial acid catalysis.更多还原