金属铟促进的各类反应

金属铟在室温下不能被空气或氧气氧化,这与其它金属比起来是一个很大的优势。铟促进的反应在室温下在水中就可顺利进行,不需要加热也不需要超声波进行辅助。综述了金属铟近年来参与的各类有机反应,诸如烯丙基化反应、炔丙基化反应等,总结了这些化学反应的最新研究进展并介绍了金属铟促进的一些新型反应的特点及其优势。     

水相有机金属反应

水相有机金属反应具有很强的经济竞争力和实际应用的良好前景,它的发展及在有机合成中的应用具有重要的理论意义。综述了锌促进、铟促进等水相有机金属反应。     

金属铟促进下有机相中合成高烯丙基醇

主要研究了以四氢呋喃作为反应溶剂,三甲基氯硅烷作为活化剂,金属铟促进下醛与烯丙基溴生成高烯丙基醇的反应。讨论了三甲基氯硅烷的用量及了不同反应底物对反应的影响,得出反应的最佳条件是三甲基氯硅烷与醛的比2/1,并且发现只有吸电子基及卤素取代的芳香醛反应速度较快,收率好,其它醛的反应较复杂。     

过渡金属催化下醛的烯丙基化反应研究进展

烯丙基醇在有机合成中是一类重要中间体,醛的烯丙基化反应是制备烯丙基醇的一类重要方法,其中过渡金属作为催化剂,在该领域获得了突飞猛进的发展。文章综述了近两、三年来在过渡金属催化下金属烯丙基试剂及其替代品与醛的烯丙基化反应研究进展。     

从电炉炼锌烟尘及其酸浸出渣中综合回收有价金属的工艺研究

系统地研究了从电炉炼锌烟尘及其酸浸出渣中综合回收铟、锡、铅、锌等有价金属的新工艺,考察了硫酸浸取锌、铟,盐酸浸取铅、锡的最佳工艺控制条件。该工艺方法能够有效地回收电炉炼锌烟尘中的铟、锡、铅、锌等有价金属,工艺简单实用,原料综合利用率高,无环境污染等特点。铟、锡、铅、锌的回收率分别可达82%、98%、97%和95%。     

烟化法综合处理铅锑鼓风炉渣的工艺实践

因历史原因,河池地区有大量铅锑矿鼓风炉冶炼渣富集有价金属铅、锑、锌、铟等,以前受冶炼技术条件限制而无法回收,大量冶炼渣长期堆存。采用烟化炉还原挥发处理铅锑鼓风炉冷渣,可以综合回收其中锌、锑、铅、铟等有价金属。介绍了烟化炉全冷料还原挥发的操作条件和技术指标,对烟化炉生产过程中常见故障的发生原因及处理方式也进行了介绍。     

真空蒸馏法脱除金属铟中Cd、Zn、Tl、Pb的研究

通过理论论证了铟与镉、铊、铅、锌分离的可能性,研究了采用真空蒸馏的方法脱除镉、铊、铅、锌到4N精铟要求的工艺条件。实验表明,控制蒸馏温度1 000℃,恒温时间270 m in,可以将镉、铊、铅、锌的含量降到4N国家标准,整个过程中,金属铟的挥发率为9.44%。     

亚砜配体在金属催化烯丙基官能团化反应中的应用

过渡金属催化的烯丙基官能团化反应在有机合成中具有重要作用，是构建碳碳键和碳杂原子键的重要方法。亚砜配体以其独特的立体化学性质，不仅在传统的（Tsuji-Trost）烯丙基取代反应中取得优异结果，而且在烯丙基碳氢活化反应中展现出巨大潜力。本文根据产生烯丙基钯中间体的催化反应机理及亚砜配体配位模式的不同，总结了近些年亚砜配体在传统的烯丙基取代、烯丙基碳氢官能团化及不对称烯丙基碳氢官能团化领域的最新研究进展，指出影响各个催化体系的关键因素及所存的问题并对今后发展做出了展望。     

还原挥发氧化锌烟尘中有价金属分离工艺研究

针对含多种有价金属的还原挥发氧化锌烟尘,提出一条全湿法分离烟尘中有价金属的工艺路线。首先采用加双氧水氧化稀硫酸浸出,经过滤和洗涤,分别获得含硫酸锌、硫酸铟浸出液和含铅、铋浸出渣,实现锌、铟与铅、铋分离;对含硫酸锌和硫酸铟浸出液采用P204萃取,实现锌与铟的分离;对含铅、铋浸出渣采用碳酸氢铵转化生成碳酸铅,加硝酸溶解,实现铅与铋的分离。该工艺不仅可有效分离烟尘中的有价金属,而且获得的硫酸锌、硫酸铟、硝酸铅、富铋渣可用于生产其他化工产品,为氧化锌烟尘高效综合利用提供了一条新的途径。     

离子交换纤维分离含铁铟和锌的混合溶液

正一、项目简介在湿法冶金中用于同时含有三价和二价金属离子的三价金属或二价金属的富集,浓缩和提纯。由北京理工大学自行开发的新材料。二、现状特点目前已完成实验室模拟样品的分离和富集。三、技术创新采用离子交换纤维柱逐个分离提纯含铁铟和锌混合溶液中的铁、铟和锌。四、应用范围在湿法冶金中用于同时含有三价和二价金属离子的三价金属或二价金属的富集,浓缩和提纯。     

Lewis Acid‐Catalyzed Oxidative Allylation: A New Approach for the Synthesis of Homoallylic Alcohols and Amines Directly from Alcohols

A new approach for the synthesis of homoallylic alcohols and amines directly from alcohols via one‐pot sequential oxidation–Barbier reaction and oxidation–condensation–Barbier reactions, respectively, is reported. The protocol involves the one‐pot ferric chloride‐catalyzed oxidation of alcohols to the corresponding aldehydes with chloramine‐T followed by indium‐mediated Barbier allylation with allyl bromide to afford homoallylic alcohols in 70–90% overall yields. The ferric chloride‐catalyzed condensation of aldehydes and oxidation by‐product p‐toluenesulfonamide followed by indium‐mediated Barbier‐type allylation of the resulting aldimines with allyl bromide affords homoallylic amines in 60–80% overall yields in the same reaction vessel. The present work demonstrates a new one‐pot approach toward homoallylic alcohol and amine synthesis directly from alcohols.     

Catalytic Use of Zinc Amide for Transmetalation with Allylboronates: General and Efficient Catalytic Allylation of Carbonyl Compounds,Imines, and Hydrazones

The efficient catalytic allylation of ketones, imines, and hydrazones with allylboronates using a catalytic amount of zinc amide is reported. In this reaction, the boron‐to‐zinc exchange process occurred smoothly to afford the corresponding allylzinc amides, and the desired allylation reactions proceeded in high efficiency (∼0.1 mol%). A mechanistic study revealed that transmetalation was a rate‐determining step in the catalytic cycle, and also that the amide ligand on the zinc center played a key role in preparing reactive allylzinc species. Catalytic asymmetric allylations were also investigated, and high enantioselectivities were obtained using chiral diamine ligands.     

含铟氧化锌烟尘加压硫酸浸出工艺优化

对含铟氧化锌烟尘加压浸出进行正交实验及单因素实验,考察各因素对浸出的影响. 结果表明,各因素对铟浸出率的影响显著程度为初始硫酸浓度>液固比>压力>温度>时间,对锌浸出率为初始硫酸浓度>液固比>温度>时间>压力. 优化工艺条件为温度140℃,釜内压力0.6 MPa,时间90 min,液固比8 mL/g,初始硫酸浓度160 g/L,搅拌速率500 r/min. 该条件下锌和铟浸出率分别达99%和91%以上,锌与铟可同时高效浸出,浸出液残酸低,工艺稳定性好     

Zinc deposition and dissolution in methanesulfonic acid onto a carbon composite electrode as the negative electrode reactions in a hybrid redox flow battery

Electrodeposition and dissolution of zinc in methanesulfonic acid were studied as the negative electrode reactions in a hybrid redox flow battery. Cyclic voltammetry at a rotating disk electrode was used to characterize the electrochemistry and the effect of process conditions on the deposition and dissolution rate of zinc in aqueous methanesulfonic acid. At a sufficiently high current density, the deposition process became a mass transport controlled reaction. The diffusion coefficient of Zn²⁺ ions was 7.5 × 10⁻⁶ cm² s⁻¹. The performance of the zinc negative electrode in a parallel plate flow cell was also studied as a function of Zn²⁺ ion concentration, methanesulfonic acid concentration, current density, electrolyte flow rate, operating temperature and the addition of electrolytic additives, including potassium sodium tartarate, tetrabutylammonium hydroxide, and indium oxide. The current-, voltage- and energy efficiencies of the zinc-half cell reaction and the morphologies of the zinc deposits are also discussed. The energy efficiency improved from 62% in the absence of additives to 73% upon the addition of 2 × 10⁻³ mol dm⁻³ of indium oxide as a hydrogen suppressant. In aqueous methanesulfonic acid with or without additives, there was no significant dendrite formation after zinc electrodeposition for 4 h at 50 mA cm⁻².     

硫酸体系中P507对铟锌锰的萃取分离研究

根据软锰矿和闪锌矿在酸性条件下同槽浸出所得浸出液特点(含铟、锌、锰离子),用P507萃取浸出液中的铟,分离出锌和锰。考察了平衡水相酸度(氢离子浓度)、萃取剂体积分数、萃取温度、有机相与水相体积比、萃取时间等因素对铟萃取率的影响。研究结果表明:在室温下,在平衡水相酸度为2.5 mol/L、P507体积分数为30%(30%P507+70%磺化煤油)、有机相与水相体积比为1∶1、萃取时间为10 min条件下,铟的一级萃取率在99%以上,锌和锰一级萃取率在1.20%以下,铟与锌和锰的分离达到最佳效果;负载有机相经水洗,锌和锰洗涤率为99%,铟洗涤率为0;用2.0 mol/L盐酸进行反萃,铟反萃率在98%以上,达到了富集铟分离锌和锰的目的。     

Highly Enantioselective Allylation of Aromatic α‐Keto Phosphonates Catalyzed by Chiral N,N′‐Dioxide‐Indium(III) Complexes

The ramipril derivative N,N′‐dioxide 3g ‐indium(III) complex was found to be an efficient catalyst for the allylation of the aromatic α‐keto phosphonates. The corresponding α‐hydroxy phosphonates were obtained with high yields (up to 98 %) and high enantioselectivities (up to 91 % ee). A bifunctional catalyst system was described with an N‐oxide as Lewis base activating tetraallyltin and indium as Lewis acid activating aromatic α‐keto phosphonates. A possible catalytic cycle has been proposed to explain the mechanism of the reaction.     

Kinetics of the allylation of phenoxide by polyethylene glycol in a two-phase reaction

Polyethylene glycol (PEG) was used as the phase transfer catalyst in the two-phase allylation of phenoxide with allyl chloride. The kinetics of the reaction both in the organic phase and in the aqueous phase was studied in detail based on the ion-extraction mechanism. The reaction rates both in the organic and aqueous phases were increased by PEG. The concentration of phenoxide in the organic phase results from adding PEG followed by a reaction second order in the concentration of phenoxide in the aqueous phase. This is due to the ability of PEGs to form complexes with sodium cations. In the aqueous phase, the PEG will enhance the solubility of allyl chloride.     

Low-Oxidation State Indium-Catalyzed C-C Bond Formation

The development of innovative metal catalysis for selective bond formation is an important task in organic chemistry. The group 13 metal indium is appealing for catalysis because indium-based reagents are minimally toxic, selective, and tolerant toward various functional groups. Among elements in this group, the most stable oxidation state is typically +3, but in molecules with larger group 13 atoms, the chemistry of the +1 oxidation state is also important. The use of indium(III) compounds in organic synthesis has been well-established as Lewis acid catalysts including asymmetric versions thereof. In contrast, only sporadic examples of the use of indium(I) as a stoichiometric reagent have been reported: to the best of our knowledge, our investigations represent the first synthetic method that uses a catalytic amount of indium(I). Depending on the nature of the ligand or the counteranion to which it is coordinated, indium(I) can act as both a Lewis acid and a Lewis base because it has both vacant p orbitals and a lone pair of electrons. This potential ambiphilicity may offer unique reactivity and unusual selectivity in synthesis and may have significant implications for catalysis, particularly for dual catalytic processes. We envisioned that indium(I) could be employed as a metallic Lewis base catalyst to activate Lewis acidic boron-based pronucleophiles for selective bond formation with suitable electrophiles. Alternatively, indium(I) could serve as an ambiphilic catalyst that activates both reagents at a single center. In this Account, we describe the development of low-oxidation state indium catalysts for carbon-carbon bond formation between boron-based pronucleophiles and various electrophiles. We discovered that indium(I) iodide was an excellent catalyst for α-selective allylations of C(sp(2)) electrophiles such as ketones and hydrazones. Using a combination of this low-oxidation state indium compound and a chiral semicorrin ligand, we developed catalytic highly enantioselective allylation, crotylation, and α-chloroallylation reactions of hydrazones. These transformations proceeded with rare constitutional selectivities and remarkable diastereoselectivities. Furthermore, indium(I) triflate served as the most effective catalyst for allylations and propargylations of C(sp(3)) electrophiles such as O,O-acetals, N,O-aminals, and ethers, and we applied this methodology to carbohydrate chemistry. In addition, a catalyst system composed of indium(I) chloride and a chiral silver BINOL-phosphate facilitated the highly enantioselective allylation and allenylation of N,O-aminals. Overall, these discoveries demonstrate the versatility, efficiency, and sensitivity of low-oxidation state indium catalysts in organic synthesis.