氢氧化镁-硼酸锌复合阻燃剂辅助制备产率高和电容性能优异的煤焦油沥青基多孔碳

以煤焦油沥青为前驱体，氢氧化镁-硼酸锌复合阻燃剂为助剂，直接在空气条件下高温碳化制备了煤沥青基多孔碳，并探究其电化学性能。得益于阻燃剂的阻燃作用协同其活化、掺杂功能化作用，得到了高产率(55.1%)、多原子(N、B、O)掺杂且具有分级多孔结构的多孔碳。将其作为超级电容器电极材料，在三电极体系中0.5 A·g^-1电流密度下比电容可达344 F·g^-1。此外，以制备的多孔碳和壳聚糖基氨基酸质子盐凝胶电解质组装的柔性对称电容器具有29.3 Wh·kg^-1的高能量密度，在50 000次循环后电容保持率为96.9%，且在-25~75℃温度区间内可正常工作，显示出宽的温度使用范围。     

超高比表面积氮掺杂多孔碳材料的制备及其超级电容性能

以蔗糖为碳源,尿素为氮源,草酸钾为活化剂,通过简单的研磨和高温碳化制备了具有超高比表面积(大于3 000 m²·g^-1)的氮掺杂多孔碳材料。采用多种手段对多孔碳材料的微观形貌、比表面积、孔结构和表面氮物种进行了表征,探究了不同温度下草酸钾和尿素对碳材料的比表面积、氮含量和超级电容性能的影响。结果表明,仅使用草酸钾作为活化剂制备的碳材料KC-800 的比表面积为 1 114 m2·g^-1,而同时使用草酸钾和尿素制备的样品 KNC-800 的比表面积高达 3 033 m²·g^-1。在以 6.0mol·L^-1 KOH 为电解液的三电极体系中,当电流密度为 0.5 A·g^-1时,KNC-800 的比电容为 405 F·g^-1,而 KC-800 的比电容仅为248 F·g^-1。这表明草酸钾和尿素的加入显著提高了多孔碳材料的比表面积和超级电容性能。电容贡献分析表明,KNC-800的双电层电容值和赝电容值均高于KC-800。KNC-800在电流密度为0.5 A·g^-1时经过10 000次循环后仍能保持98.3%的初始比电容,表现出优异的循环性能。     

用于高性能钠离子电容器的高氮掺杂多孔碳纳米纤维的简易合成

选择合适的生物质材料是获得功能碳材料的有效途径之一。通过柠檬酸钾和三聚氰胺一步热解法制备高氮掺杂多孔碳纳米纤维(NPCF)。在电流密度为0.1和1.0 A·g^-1时,NPCF电极的容量分别为218和140 mAh·g^-1。同时,具有NPCF阳极的钠离子电容器(SIC)在1.0 A·g^-1下表现出优异的倍率性能和超长的使用寿命,可循环超过2 500次。     

用于高性能钠离子电容器的高氮掺杂多孔碳纳米纤维的简易合成

选择合适的生物质材料是获得功能碳材料的有效途径之一。通过柠檬酸钾和三聚氰胺一步热解法制备高氮掺杂多孔碳纳米纤维(NPCF)。在电流密度为0.1和1.0 A·g^-1时,NPCF电极的容量分别为218和140 mAh·g^-1。同时,具有NPCF阳极的钠离子电容器(SIC)在1.0 A·g^-1下表现出优异的倍率性能和超长的使用寿命,可循环超过2 500次。     

硼、氮共掺杂多孔碳的制备及其超电容性能

分别以含氮菲咯啉、四硼酸钾和醋酸锌为碳源、活化剂和模板,制备了B、N共掺杂多孔碳(BN-PC),并探究模板质量对BN-PC结构和储电性能的影响。当醋酸锌质量为5g时,所得BN-PC₅中B、N杂原子含量分别为 20.21%、18.29%。电化学测试结果表明,以6 mol·L^-1 KOH为电解液,BN-PC₅电极展现出高的比电容(在0.05 A·g^-1电流密度下为255 F·g^-1)、优异的倍率性能(在20A·g^-1电流密度下为188F·g^-1)和卓越的循环稳定性(在5 A·g^-1的电流密度下循环10 000次比电容保持率为97%)。以3 mol·L^-1 ZnSO₄为电解液,在平均功率密度为56W·kg^-1时,BN-PC₅电容器的能量密度可达27Wh·kg^-1。     

低成本硫掺杂多孔碳材料的制备及其超级电容性能

以廉价的胶态二氧化硅为模板,蔗糖为碳源,硫酸为预碳化试剂和硫源,通过硬模板法制备了相对廉价的硫掺杂多孔碳(SSC-T,T℃代表碳化温度)材料。采用多种表征方法对多孔碳材料的微观形貌、孔道结构、比表面积和表面硫物种进行了表征,探究了硫酸和碳化温度对多孔碳材料的微观形貌、孔道结构和比表面积的影响。结果表明,碳化温度对碳的孔结构、比表面积和硫元素的含量有显著的影响,其中900℃碳化得到的样品SSC-900具有最大的比表面积、孔体积和比电容,远高于未加入硫酸制备的碳材料SC-900,表明硫酸的加入可以提高碳材料的比表面积、孔体积,进而提高碳材料的比电容。与昂贵的有序介孔碳CMK-3相比,SSC-900具有成本更低、孔径更大和电容性能更好的优点。在以6.0 mol·L^-1 KOH为电解质的三电极体系中,在0.5 A·g^-1的电流密度下,SSC-900的比电容可以达到357 F·g^-1,而SC-900和CMK-3的比电容分别仅为152和266 F·g^-1。电容贡献分析表明,SSC-900的双层电容值和赝电容值均高于SC-900。此外,SSC-900在0.5 A·g^-1的电流密度下循环10 000次后仍能保持98.4%的初始比电容。     

低成本硫掺杂多孔碳材料的制备及其超级电容性能

以廉价的胶态二氧化硅为模板，蔗糖为碳源，硫酸为预碳化试剂和硫源，通过硬模板法制备了相对廉价的硫掺杂多孔碳(SSC-T，T℃代表碳化温度)材料。采用多种表征方法对多孔碳材料的微观形貌、孔道结构、比表面积和表面硫物种进行了表征，探究了硫酸和碳化温度对多孔碳材料的微观形貌、孔道结构和比表面积的影响。结果表明，碳化温度对碳的孔结构、比表面积和硫元素的含量有显著的影响，其中900℃碳化得到的样品SSC-900具有最大的比表面积、孔体积和比电容，远高于未加入硫酸制备的碳材料SC-900，表明硫酸的加入可以提高碳材料的比表面积、孔体积，进而提高碳材料的比电容。与昂贵的有序介孔碳CMK-3相比，SSC-900具有成本更低、孔径更大和电容性能更好的优点。在以6.0 mol·L^-1 KOH为电解质的三电极体系中，在0.5 A·g^-1的电流密度下，SSC-900的比电容可以达到357 F·g^-1，而SC-900和CMK-3的比电容分别仅为152和266 F·g^-1。电容贡献分析表明，SSC-900的双层电容值和赝电容值均高于SC-900。此外，SSC-900在0.5 A·g^-1的电流密度下循环10 000次后仍能保持98.4%的初始比电容。     

惰性盐辅助合成介孔石墨化碳片及其电容性能

以惰性盐KCl为模板、硝酸镍为金属催化剂镍源、葡萄糖为碳源,通过碳化处理制备了介孔石墨化碳片。利用扫描电子显微镜、透射电子显微镜、X-射线衍射仪和比表面测试仪对介孔石墨化碳片进行了表征。探讨了碳片形成的机理,采用三电极测试体系研究了介孔石墨化碳片电极材料的电化学性能。结果表明,10gKCl制备的碳片比表面积最大（989m²·g^-1）,在6mol·L^-1KOH电解液中,当电流密度为0.5A·g^-1时,比电容达到180F·g^-1;当电流密度达到10A·g^-1时,比电容维持在148F·g^-1,显示了电极具有较好的倍率性能;在10A·g^-1条件下,2000次循环充放电测试后电容没有发生衰减,展示了在超级电容器方面的应用潜力。     

用于高性能锂硫电池的二维氮硫共掺杂多孔碳纳米片的快速合成

本工作基于工业炼油产品沥青,开发了一种无金属、氮和硫共掺杂多孔碳纳米片（NSPC）的合成方法。获得的多孔碳纳米片具有高比表面积（339 m²·g^-1）和优异的固硫能力。同时,高含量氮、硫共掺杂可以有效增强碳材料的导电性,同时促进多硫化物的高效催化转化。通过熔融法固硫后,制备得到的NSPC/S电极具有较高的比容量和优异的循环稳定性（在0.6C电流密度下,200次循环后容量为762 mAh·g^-1）,实现了高含量氮和硫共掺杂的二维多孔碳材料的快速批量生产并用于高性能锂硫电池正极材料。     

基于含锌有机配位聚合物的微孔碳的合成及其电化学性能

报道了一种基于含锌(II)有机配位聚合物制备微孔碳的新方法. 通过锌离子和酒石酸之间的配位作用获得含锌有机配位化合物, 并通过氢键作用将其引入到间苯二酚/甲醛低聚物溶胶的开放网络结构中. 使含锌有机配位化合物和酚醛低聚物溶胶体系发生共聚反应得到酚醛和含锌有机配位共聚物, 在950℃下热处理分解以及锌蒸气蒸发后制得微孔碳. 微孔碳材料典型样品具有相对较大以及比较规则的微孔, 其比表面积可以达到1260 m²·g^-1, 孔体积为0.63 cm³·g^-1. 所得微孔碳作为超级电容器电极材料的等效串联电阻为0.46 Ω, 其循环伏安曲线展示出较好的矩形性. 恒流充放电分析结果表明, 当电流密度为1 A·g^-1时, 微孔碳电极的比电容为196 F·g^-1; 在10 A·g^-1的大电流密度下, 比电容仍然达到137 F·g^-1. 该电极具有优良的循环稳定性, 1000次循环后比电容保持率达到98%. 这一研究结果表明, 所得微孔碳在超级电容器电极材料方面具有重要的应用前景.     

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.     

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.     

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.     

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.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

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.     

Microwave-assisted copper-catalyzed stereoselective ring expansion of three-membered heterocycles with α-diazo-β-dicarbonyl compounds

Microwave-assisted copper-catalyzed ring expansions of three-membered heterocycles with α-diazo-β-dicarbonyl compounds were investigated. Thiiranes generated 3-acyl-5,6-dihydro-1,4-oxathiines in the presence of copper sulfate and trans-3-acyl-5,6-dihydro-1,4-oxathiines as stereospecific products for 1,2-disubstituted cis-thiiranes through an intramolecular S_N2 process. Oxiranes gave rise to 2-acyl-5,6-dihydro-1,4-dioxines under the catalysis of copper hexafluoroacetylacetonate and cis-3-acyl-5,6-dihydro-1,4-dioxines as stereospecific products for 1,2-disubstituted cis-oxiranes via an intimate ion-pair mechanism. The current method provides a direct and simple strategy in efficient preparation of 3-acyl-5,6-dihydro-1,4-oxathiines and 2-acyl-5,6-dihydro-1,4-dioxines, important agents in medicinal and agricultural chemistry, from readily available thiiranes and oxiranes, respectively.     

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.