酚醛树脂基球形微-介双阶多孔炭的软模板法制备

将苯酚和甲醛在碱性条件下聚合,然后在酸性条件下与软模板剂F127自组装形成中间相,经高温煅烧合成球形微-介双阶多孔炭。 通过扫描电子显微镜、透射电子显微镜、氮气吸附-脱附和热重分析技术对样品进行了形貌观察和性能测试。 结果表明,pH值、软模板剂用量和活化温度对样品形貌有调控作用。 当软模板剂F127的质量分数为20%、pH值为0.5和活化温度为700 ℃时,可制备出直径为100～200 nm的球形炭,球形粒子分散均匀,排列规整,呈明显蠕虫状排列的孔隙结构,比表面积为503 m2/g,孔容积0.416 cm3/g,介孔孔径集中分布在2.9 nm,微孔主要分布在1.3 nm。 随着活化温度升高,炭球的比表面积和孔容积增大,平均孔径减小。 F127的热解形成介孔结构,碳前驱体高温下的径向收缩形成微孔结构。     

介孔炭的直接制备及其电化学性能研究

以柠檬酸镁为原料,采用直接碳化法制备介孔炭电极材料。N2吸附测试表明,所制备多孔炭的比表面积达2 000 m2·g-1左右,介孔孔容和平均孔径随着炭化温度的升高而增加,当炭化温度大于800℃时,能够制备出以介孔结构为主的多孔炭材料。电化学测试表明,MgC-800和MgC-900具有优异的电化学电容特性。与硬模板法制备的OMC相比,MgC-800和MgC-900在实验电流密度范围内具有更大的比电容值,这应当归功于它们巨大的比表面积以及有利于电解质离子扩散的介孔结构。     

KOH活化的炭干凝胶及其储氢性能(英文)

以苯二酚与甲醛为前驱体,赖氨酸作为催化剂,快速合成了有机溶胶。有机溶胶经碳化以及KOH进一步活化,获得了具有较高微孔率和较大比表面积的炭干凝胶。研究了多孔炭干凝胶的储氢性能,比较了不同活化程度的炭干凝胶的最大储氢容量与比表面积、微孔体积以及微孔孔径分布的关系。结果表明,KOH适度活化的炭干凝胶(ACX-5)具有较高的比表面积(2 204 m2.g-1)和较大的总孔容积(1.09 cm3.g-1),在77 K和1.1 MPa氢压下时其储氢量可达4.3wt%。     

稻壳制备多孔炭对肌酐的吸附

研究了具有高比表面积稻壳基多孔炭(简称RHC)对人体内代谢产物肌酐(简称CR)的吸附, 将采用氢氧化钠活化稻壳制备的四种多孔炭和二种商业活性炭对肌酐的吸附进行了对比, 同时考察了盐酸、硝酸和双氧水对多孔炭进行表面处理及其经过高温处理(800 ℃)后对肌酐的吸附. 结果表明稻壳基多孔炭对肌酐的吸附超过商业炭,经过表面处理后多孔炭的吸附能力增强, 无氧化性盐酸处理后的多孔炭对肌酐的吸附量最大, 氧化性最强的硝酸处理后的多孔炭对肌酐的吸附量最小, 双氧水居中, 高温处理后的多孔炭吸附能力有所降低. 实验证实了多孔炭对CR的吸附符合Freundlich方程.     

由稻壳制备高比表面积活性炭

以稻壳为原料,KOH为活化剂制备了高比表面积活性炭,其比表面积超过3000m₂/g,且孔径均一,孔分布较窄.     

KOH活化木屑生物炭制备活性炭及其表征

以木屑热裂解的生物质炭为原料,氢氧化钾为活化剂,采用化学活化法制备活性炭,探讨了碱炭比、活化温度和活化时间对活性炭吸附亚甲基蓝吸附值的影响。 利用N2吸附实验、XRD和FTIR等实验技术,对原料与制备活性炭的结构与性能进行了表征。 结果表明,在碱炭质量比为1.5、活化温度750 ℃、活化时间2 h的条件下,所制备的活性炭对亚甲基蓝吸附值为255 mg/g,BET总比表面积为1514 m2/g,中孔比表面积为110 m2/g,吸附总孔容为0.821 cm3/g,中孔孔容为0.117 cm3/g,吸附平均孔径为2.170 nm。     

KOH活化糠醛渣制备活性炭机理与表征

以糠醛渣为原料、KOH为活化剂,采用两步活化法制备了活性炭。考察了活化温度、活化时间、碱炭比和浸渍时间对活性炭孔结构及吸附性能的影响。采用低温N2吸附、BET、BJH及DFT理论对活性炭孔结构进行了表征分析,利用傅里叶变换红外-拉曼光谱仪检测其表面官能团,分别使用扫描电镜和X射线衍射对其进行表观形貌观察和晶型分析。结果表明,制备活性炭的最佳工艺条件为:活化温度800℃、活化时间3h、碱炭比3∶1、浸渍时间12h。所制备的糠醛渣活性炭的吸附孔径分布集中,吸附孔容为0.8825cm2/g,DFT总比表面积为3290.5m2/g,其碘吸附值和亚甲基蓝吸附值分别为2107.32mg/g和39.67mL/0.1g。     

KOH活化糠醛渣制备活性炭及其表征

以糠醛渣为原料、KOH为活化剂,采用两步活化法制备了活性炭。考察了活化温度、活化时间、碱炭比和浸渍时间对活性炭孔结构及吸附性能的影响。采用低温N2吸附、BET、BJH及DFT理论对活性炭孔结构进行了表征分析,利用傅里叶变换红外-拉曼光谱仪检测其表面官能团,分别使用扫描电镜和X射线衍射对其进行表观形貌观察和晶型分析。结果表明,制备活性炭的最佳工艺条件为:活化温度800℃、活化时间3h、碱炭比3∶1、浸渍时间12h。所制备的糠醛渣活性炭的吸附孔径分布集中,吸附孔容为0.8825cm2/g,DFT总比表面积为3290.5m2/g,其碘吸附值和亚甲基蓝吸附值分别为2107.32mg/g和39.67mL/0.1g。     

多孔聚苯胺-稻壳基白炭黑复合物的制备及循环伏安特性

以工业生产废弃的稻壳灰为原料,采用化学沉淀法制备了大孔径多孔稻壳基白炭黑,并在多孔白炭黑(RHSi)分散体系中,采用原位聚合法制备了聚苯胺(PAn)-稻壳基白炭黑复合物.采用热重分析、傅里叶红外光谱、透射电镜、低温氮吸附法和循环伏安法研究了复合物的结构及电化学性能.结果表明:聚苯胺-稻壳基白炭黑复合物具有多孔聚集体结构.当m_(PAn)/m_(RHSi)＝0.434时,复合物的比表面积为42.1 m~2/g,最可几孔径约为22 nm,适宜负载生物大分子,且在酸性及中性溶液中具有良好的电化学可逆性.     

以稻壳热解炭制备镧负载多孔炭复合电极材料

利用稻壳热解炭为原料制备镧负载多孔炭复合电极材料(La/PCs),先将稻壳热解炭分离出炭前驱体,再采用原位活化/负载的方法制备一系列镧负载多孔炭复合电极材料,分别考察了煅烧温度和浸渍比对其吸附性能和电化学性能的影响.采用X射线衍射(XRD)、 X射线光电子能谱(XPS)、扫描电子显微镜/X射线能谱仪(SEM-EDS)和Brunauer-Emmett-Teller比表面积(BET)法研究了该系列镧负载多孔炭复合电极材料的金属结构与价态、元素组成及表面形貌,并分析了孔结构与电容值之间可能存在的关系.结果表明,在6 mol/L KOH电解液中, La/PC＿900/10材料的电容值为269.45 F/g.在电流密度为0.5 A/g时,由其组装的对称超级电容器具有23.45 W·h/kg的能量密度,此时的功率密度为0.70 kW/kg,并且循环5000次后的电容保持率为86.41%.La/PC＿900/10良好的电容性能显示了其作为碳基电极应用于高性能超级电容器的潜力.研究结果为稻壳热解炭的利用和镧在新能源材料领域的应用提供了一条可行路径.     

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%.     

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.     

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.     

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.     

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.     

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.     

A general and convenient synthesis of 4-(tosylmethyl)semicarbazones and their use in amidoalkylation of hydrogen,heteroatom, and carbon nucleophiles

A general synthesis of previously unknown semicarbazone-based α-amidoalkylating reagents, 4-(tosylmethyl)semicarbazones, has been developed. The synthesis involved three-component condensation of semicarbazones of aliphatic or aromatic aldehydes with the same or other aldehydes and p-toluenesulfinic acid. The scope and limitations of this reaction were investigated. The compounds obtained were demonstrated to be an efficient α-(4-semicarbazono)alkylating agents. They were reacted with H- (sodium borohydride), O- (sodium methylate), S- (sodium phenylthiolate), N- (pyrrolidine, sodium succinimide), P- (trialkyl phosphites), and C-nucleophiles (sodium diethyl malonate) to give the corresponding products of the tosyl group substitution, 4-substituted semicarbazones, including analogues of nitrofurazone. Among the prepared compounds tested in vitro for antibacterial and antifungal activity, three nitrofuryl-containing semicarbazones exhibited high biological activities with minimum inhibitory concentration (MIC) values of 8–32 μg/mL.     

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.     

Synthesis of novel chiral bidentate hydroxyalkyl-N-heterocyclic carbene ligands and their application in palladium-catalyzed Mizoroki–Heck couplings and asymmetric addition of diethylzinc to benzaldehyde

A small library of new chiral bidentate hydroxyalkyl-imidazolium salts 1 is conveniently synthesized on multi-gram scale from inexpensive and commercially available chiral pool amino acids. The corresponding carbenes, generated by deprotonation of imidazolium salts 1, in combination with palladium(II) chloride were tested in the Mizoroki–Heck coupling reaction. The most significant results in terms of yields and reactivities were achieved with low catalyst loading. The catalytic activities of these imidazolium salts were also investigated in the asymmetric addition of diethylzinc to benzaldehyde. The use of MgO nanoparticles as an additive in conjunction with these ligands played a crucial role in increasing the efficiency of these reactions.