盐湖镁资源的开发和利用*

我国盐湖镁资源品位高、储量大、易于开采,但目前的开发利用明显滞后,在一定程度上影响了盐湖其它资源的可持续开发和综合利用。本文针对我国盐湖镁资源的特点,综述了和盐湖镁资源开发利用相关的氢氧化镁、氧化镁、金属镁、镁合金、氯氧镁水泥和镁质晶须的开发及研究进展,并对我国盐湖镁资源的开发利用提出了一些建议。     

盐湖资源的开发和综合利用技术

中国是世界上盐湖资源最丰富的国家之一,钾、钠、锉、镁资源储量巨大.随着我国国民经济特别是农业的持续发展,要以钾为龙头,注重资源的综合利用,加快盐湖资源的开发。本文评述了我国盐湖资源的特点、开发现状和现阶段盐湖资源开发和综合利用中有代表性的化工技术:冷结晶法生产氛化钾、从盐湖资源制取硫酸钾、卤水中锉的分离提取、水氯镁石脱水和热解技术以及盆湖资源的深加工和高值化。     

我国锂资源及其开发技术进展

介绍了我国盐湖锂资源的现状及其开发技术的进展情况,讨论了各种提锂工艺的优缺点,并对现阶段我国盐湖锂资源的开发提出了建议。     

盐湖资源开发利用进展

本世纪头十年里,国际上再度掀起盐湖资源开发热潮。这很大程度上是由于锂的开发热带动的,同时也是和钾肥的广泛施用、价格一路走高有关。南美安第斯高原地区盐湖蕴藏世界70%以上的锂资源,且卤水锂、钾、硼浓度高。该地区极度干旱,少雨多风,非常适合采用卤水盐田蒸发的节能浓缩工艺技术。老的盐湖开发企业则在钾肥需求的带动下,稳步发展。在我国,新疆罗布泊和青海柴达木盆地盐湖则钾锂镁硼产品多元化,经营多元化取得长足进步。本文对近十年来,国内外盐湖开发的新动向做了概括介绍,特别着重于南美"锂三角"地区这一新的生长点。     

忆纪如老师

纪如老师是我国盐湖资源研究开发的开拓者、最先的倡导人和组织者,他领导中国科学院化学研究所30年,创建了中国科学院青海盐湖研究所。在近60年的科研工作与科研组织领导工作中,先生以其渊博学识、科学远见、强烈社会责任感和献身科学事业的无私精神,为我国的化学发展与     

火焰原子发射光谱法测定卤水中锂

卤水是天然水中矿化度很高的水,也被称为液态矿。柴达木盆地具有非常丰富的盐湖资源,特别是锂资源,具有储量大、品位高、分布集中的特点,号称世界三大锂矿区之一。在利用盐湖锂资源开发制备锂盐的生产过程中,随着盐湖卤水的不断蒸发浓     

锂离子选择性吸附材料的制备与提取应用

近年来,随着锂电池技术和电动汽车的快速发展和大规模应用,锂资源的市场需求呈现出急剧增长的态势,矿石锂和卤水锂资源开发产量已无法满足市场需求。从地表盐湖卤水、深层卤水等液态资源中提锂具有巨大的市场开发潜力,是当前锂资源开发的重要研究方向。吸附法适用于我国低浓度大体积卤水中锂的提取,而锂离子选择性吸附材料是吸附提锂的核心。本文综述了有机(冠醚)、无机(铝基、锰基和钛基)以及复合型选择性锂吸附材料的制备方法、吸附性能和吸附机理,为研究新型锂吸附材料、克服材料缺陷以及改进吸附剂性能提供参考,以期推动盐湖卤水锂资源高效提取利用的进一步发展。     

当雄错盐湖卤水提钾盐田日晒工艺扩大试验研究

西藏现代钾锂硼特种盐湖的钾盐开发将对我国钾盐需求形成有利补充。本文首次采用蒸发结晶、分步分离的方法,进行了当雄错盐湖碳酸盐型卤水提钾多级盐田日晒工艺扩大试验研究。通过对卤水蒸发析盐全过程做化学分析和物料衡算,确定了钾、硼等重要无机元素的成盐类型和析盐阶段,以及锂、铷等稀有元素的富集规律,最终获得了较高品位钾混盐和高浓母卤,并取得了大量第一手数据资料,为今后实现当雄错盐湖卤水钾盐资源的产业化开发提供了切实可靠的中试基础和设计参考。     

必须重视盐湖资源的开发与利用

盐湖是我国丰富的资源,我国的盐湖具有数量多、储量大、稀散元素丰富、盐湖类型齐全的特点,应是我国无机化学研究的重要内容之一。在中国化学会无机化学论文报告会期间,举行了盐湖化学座谈会。中国化学会副理事长、青海盐湖研究所的首创人柳大纲同志参加了会议,与会代表进行了热烈的讨论,提供了不少有益的建议。     

从氯化镁饱和溶液中萃取锂的研究

一、前言锂是重要的战略物资,随着我国国民经济的发展,对锂的需要量日益增加。盐卤是锂的主要资源之一,我国有着极为丰富的盐湖资源,例如,青海有藏量很大的大柴旦等盐湖,四川有丰富的井卤资源。遵照伟大领袖毛主席关于“综合利用大有文章可做”的教导,开展盐湖     

二氧化碳和丙烯直接合成甲基丙烯酸的NiPMo/TiO2催化剂的研究

用溶胶-凝胶法以磷钼酸(MPA)的镍盐溶液水解钛酸四丁酯制备了NiPMo/TiO2催化剂.使用ICP、 XRD、 TG-DTA、 IR、 TPD-MS和微反应技术研究了催化剂的化学组成、热稳定性、化学吸附性质和催化反应性能.杂多钼酸盐与TiO2通过O2-在TiO2表面发生了键合.在623 K下,杂多阴离子仍保持原有的Keggin结构.CO2在Lewis酸位Ni(Ⅱ)和Lewis碱位Ni-O-Mo的桥氧协同作用下生成CO2卧式吸附态Ni(Ⅱ)←O-(CO)←(O--Ni).丙烯有多种吸附态在催化剂上吸附.在563 K、 1 MPa和空速1500 h-1的反应条件下,丙烯的摩尔转化率为3.2%,产物MAA选择性为95%.     

Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction

In the context of the preparation of camptothecin and luotonin A analogs, the synthesis of some key keto-precursors and their use in Friedländer condensation are described. This paper also focuses on the stability of these keto intermediates and emphasizes the major differences between indolizinones and pyrroloquinazolinones series. Noteworthy is also the report of some original structures isolated as by-products of some experiments.     

CoFe2O4自形成磁性液体场致结构化对磁化的影响

The Langevin paramagnetic theory can’t describe the relation between magnetization of ferrofluids and applied magnetic field. The structuralization of ferrofluids, which is considered the main influence factor of the magnetization, is regarded. The part of magnetization works is deposited when the structure is forming. This action influences the magnetization of ferrofluids directly or indirectly. On the base of the “compressing” model, the Langevin function that usually describes the magnetization of ferrofluid is modified, and a well-fitted curve is obtained. An equation of the relation between the equivalent volume fraction after being “compressed” and the intensity of magnetic field is discovered, which approximately describes the process of magnetization. The relation between the approximate initial susceptibility and the volume fraction can be obtained from modified formula.     

KMnO4-mediated oxidative CN bond cleavage of tertiary amines: Synthesis of amides and sulfonamides

KMnO₄-mediated oxidative CN bond cleavage of tertiary amines producing secondary amine was introduced, which was trapped by electrophiles (acyl chloride and sulfonyl chloride) to form amides and sulfonamides. The reaction could take place at mild condition, tolerating a wide range of function groups and affording products in moderate to excellent yields.     

Highly regioselective Buchwald–Hartwig amination at C-2 of 2,4-dichloropyridine enabling a novel approach to 2,4-bisanilinopyridine (BAPyd) libraries

The highly regioselective Buchwald–Hartwig amination at C-2 of the cheap and readily accessible reagent, 2,4-dichloropyridine with a range of anilines and heterocyclic amines is described. This new methodology is robust and provides a facile access to 4-chloro-N-phenylpyridin-2-amines on 0.25 mol scale. These intermediates undergo a further Buchwald–Hartwig amination at higher temperature to enable rapid exploration of the chemical space at C-4 and to provide a library of 2,4-bisaminopyridines.     

Chemistry of heterocyclic compounds at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences, over 50 years (Review)

The review contains a concise historical account and information on the most significant researches undertaken by the staff at the A. E. Favorsky Irkutsk Institute of Chemistry, Siberian Branch of the Russian Academy of Sciences on the Chemistry of Heterocyclic Compounds. Dedicated to Academician of the Russian Academy of Sciences B. A. Trofimov on his 70th jubilee. Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 10, pp. 1443–1502, October, 2008.     

Sulfur-directed metal-free and regiospecific methyl C(sp3)–H imidation of thioanisoles

Regiospecific and direct imidation of the methyl C(sp³)–H bond of thioanisoles is realized under mild and metal-free conditions with N-fluorobis(benzenesulfonyl)imide as an oxidant and nitrogen source. Proposed mechanism suggests that thionium ion intermediates and a Pummerer-type reaction are involved. The imidation has advantages such as high step-economy, excellent functionality tolerance, and regiospecificity, giving structurally diverse imidation products.     

Selective syntheses of 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones via temperature-dependent Rh(II)-carbenoid-mediated 2H-azirine-ring expansion

The Rh(II)-catalyzed reaction of 2-carbonyl-substituted 2H-azirines with ethyl 2-cyano-2-diazoacetate or 2-diazo-3,3,3-trifluoropropionate provides an easy access to 2H-1,3-oxazines and 1H-pyrrol-3(2H)-ones. These compounds can be selectively prepared from the same starting material using temperature as the only varied parameter. The 2-azabuta-1,3-diene intermediate, a common precursor for both heterocyclic products, isomerizes into 2H-1,3-oxazine under kinetic control, while 1H-pyrrol-3(2H)-one is the sole product of the reaction at elevated temperatures. According to DFT-calculations a one-atom oxazine ring contraction involving ring-opening to a 2-azabuta-1,3-diene intermediate, followed by a 1,5- and 1,2-prototropic shift leads to the consecutive formation of imidoylketene and azomethine ylide, which then further undergo cyclization to the pyrrole derivative.     

Synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives

Different approaches for the synthesis of 1-benzyloxypyrazin-2(1H)-one derivatives from simple amino acids have been investigated. A library of 33 precursors for the preparation of N-hydroxy pyrazinones was obtained in moderate to good yields.