电解法制备K_2FeO_4过程添加剂的筛选

应用电解法,并于阳极电解液中分别加入KIO4等不同种类添加剂制备K2FeO4,考察添加剂对电流效率以及FeO42-稳定性的影响规律,产品K2FeO4的结构形貌由XRD、SEM表征.结果表明,KIO4是比较理想的添加剂,在阳极液中添加质量比为0.02%的KIO4,电解1h后,电流效率可提高31.6%,K2FeO4产品的纯度相应提高了3.85%.     

高铁酸钾在中性、酸性介质中的稳定性

研究了温度、pH、醋酸钠、Fe(Ⅲ)、氯化钠等对K2FeO4,水溶液稳定性的影响.随着温度的升高,K2FeO4在酸性介质中的稳定性逐渐减弱,随pH的增大,K2FeO4的稳定性逐渐增强;在中性介质中醋酸钠能够增强K2FeO4的稳定性,而在酸性介质中,却能够加速K2FeO4的分解;在中性和酸性介质中,三价铁盐的存在能够加速K2FeO4的分解;氯化钠能增强K2FeO4的稳定性.     

高铁酸钾氧化脱除模拟轻质油中的含硫化合物

考察了K2FeO4对模拟轻质油中苯并噻吩（BT）及二苯并噻吩（DBT）的氧化性能。结果表明,水相中K2FeO4对BT、DBT的氧化活性比较低,水的存在使K2FeO4水解成黄色的Fe(OH)3而失去氧化有机硫化物的能力;在冰乙酸反应介质中,K2FeO4对BT及DBT的氧化活性有了明显的提高;固体催化剂KM的加入显著提高了乙酸反应介质中K2FeO4对BT及DBT的氧化活性。常温、常压,醋酸/模拟油体积比为1.0,K2FeO4/S摩尔比为1.0,KM/K2FeO4质量比为1.0的条件下,DBT的转化率达98.4%,BT的转化率为70.1%。     

CoTiO3改性K2FeO4电极的电化学行为

CoTiO3改性K2FeO4电极的电化学行为;K2FeO4;CoTiO3;改性电极; 放电电位     

电解合成Na2FeO4制备K2FeO4

复分解;电解合成Na2FeO4制备K2FeO4     

K2FeO4在稀KOH溶液中的稳定性研究

采用分光光度法对K2FeO4在初始pH=8.0～13.0的KOH溶液中的稳定性作了系统研究.研究发现,在恒定温度下,K2FeO4的稳定性受其浓度、溶液的碱度和其分解产物FeOOH的催化分解作用三方面影响.HO-离子浓度的增大将阻碍FeO2-4离子之间的碰撞,从而有利于增强K2FeO4的稳定性,但HO-离子浓度增大到一定程度后,K2FeO4的分解产物容易生成FeOOH,而FeOOH将催化K2EeO4的进一步分解.研究结果表明,0.5 mmol·L-1的K2Fe04在pH=10.0～11.0的KOH溶液中最稳定,其初始阶段分解过程为-级反应;溶液初始pH值不同,K2FeO4的稳定性随其浓度变化的规律亦不相同.     

Studies on the Electrochemical Characteristics of K2FeO4 Electrode

Discharge performance of K2FeO4 electrode under different conditions was studied by the constant electric current discharge method. The electrochemical characteristics of K2FeO4 electrode were investigated for the first time by means of cyclic voltammetry. The results show that the K2FeO4 electrode made at moderate pressure (20MPa) and discharged at lower current has better discharge performance. It is also found that K2FeO4 electrode is significantly rechargeable.     

高铁酸钾去除微污染水源水中氰化物的试验研究

以高铁酸钾(K2FeO4)为氧化剂,对微污染水源水中微量 CN- 的去除进行了研究,考察了 pH、温度、反应时间、K2FeO4 投加量、CN- 初始浓度等因素对 CN- 去除的影响;并对用 K2FeO4 氧化除 CN- 机理进行了初步探讨.结果表明,pH 在7～10.5范围内,CN- 去除率随着 pH 的上升而升高;温...     

FeO_4~(2-)在碱性缓冲水溶液中的稳定性

研究了在pH=9.40的碱性缓冲水溶液中,K2FeO4初始浓度、温度以及不同介质对42-稳定性的影响.结果表明,随K2FeO4初始浓度和温度升高,FeO42-稳定性下降;Fe3+使FeO42-稳定性迅速下降,且加入氯化铁的FeO42-比加入硝酸铁的FeO42-稳定;磷酸钠和草酸钠使FeO42-的稳定性降低,而氯化钾、氯化钠、醋酸钠能不同程度地增强FeO42-的稳定性,其中氯化钾的效果最好.     

电解条件对电化学法制备FeO42-的影响

以铁丝网作阳极,应用电解氧化法制备FeO42-溶液,并合成固体K2FeO4.研究电解条件(如搅拌、超声、静置、温度、电流密度等)对该制备过程电流效率的影响规律.结果表明:以14 mol/L NaOH作电解液,于30℃、10 mA.cm-2及搅拌作用下电解,可获得较高的电流效率.     

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.     

关于"对‘燃料电池物理及化学性能的有限时间热力学分析方法'的讨论”答复

把有限时间热力学理论用于化学过程的研究,将会得到一系列新的结论,开展这方面的研究是很有意义的.文献[1]以燃料电池为例,在同时考虑化学反应及传热不可逆性的情况下,研究了燃料电池的性能界限,文献[2]指出了文献[1]计算化学反应及传热不可逆性而引起系统与有关环境的总熵产生率的错误以及由此而导致的结论所存在的问题,并进行了富有启发性的分析与讨论.但文献[2]对于系统与有关环境的总熵产生率的计算也是不正确的,由此得到的其它结论自然不能成立.本文将就此情况下系统与有关环境的总熵产生率的计算再次进行讨论,并给出电池功率和效率的有限时间热力学性能界限.