十三氟辛基修饰的疏水有机-无机杂化二氧化硅膜孔结构、氢气分离及水热稳定性

采用1,2-双（三乙氧基硅基）乙烷（BTESE）和十三氟辛基三乙氧基硅烷（PFOTES）为前驱体,在酸性条件下通过溶胶-凝胶法制备了十三氟辛基修饰的有机-无机杂化SiO₂膜材料。利用接触角测量、红外光谱、动态光散射和N₂吸附等测试技术分别对膜材料的疏水性、溶胶粒径和孔结构进行表征,并深入研究有支撑膜材料的氢气渗透、分离性能以及长期水热稳定性。结果表明,十三氟辛基修饰后的膜材料由亲水性变成了疏水性,当n_PFOTES/n_BTESE=0.6时膜材料对水的接触角达到（110.4±0.4）°,膜材料还保持微孔结构,孔径分布在0.5~0.8nm。氢气在修饰后的膜材料中的输运遵循微孔扩散机理,在300℃时,氢气的渗透率达到8.5×10^-7mol·m^-2·s^-1·Pa^-1,H₂/CO₂,H₂/CO和H₂/SF₆的理想分离系数分别为5.49,5.90和18.36,均高于相应的Knudsen扩散分离因子。在250℃且水蒸气物质的量分数为5%水热环境下陈化250h,氢气渗透率和H₂/CO₂的理想分离系数基本保持不变,膜材料具有良好的水热稳定性。     

疏水介孔二氧化硅膜的制备与表征

用甲基三乙氧基硅烷(MTES)代替部分正硅酸乙酯(TEOS)作为前驱体，以聚乙烯醚-聚丙烯醚-聚乙烯醚三嵌段共聚物(P123)作有机模板剂，通过共水解缩聚反应制备了甲基修饰的介孔SiO₂膜。利用N₂吸附、FTIR、²⁹Si MAS NMR以及接触角测量仪对膜的孔结构和疏水性进行了表征。结果表明，修饰后的膜材料具有良好的介孔结构，最可几孔径为4.65 nm，孔体积为0.69 cm³·g^-1，比表面积为938.4 m²·g^-1；同时疏水性明显提高，当n_MTES/n_TEOS达到1.0时，其对水的接触角达到109°± 1.1°。气体渗透实验表明气体通过膜孔的扩散由努森机制所控制。     

两步变温晶种法制备丝光沸石膜及其渗透汽化乙酸脱水性能

在水热晶种法基础上采用两步变温晶化以高水硅比(n_H2O/n_SiO2)稀溶液配方为合成液,研制用于渗透汽化(PV)乙酸脱水的丝光沸石膜(MOR膜),考察了变温晶化各段时间、水硅比与氟离子对 MOR膜的形貌与分离性能的影响规律。结果表明：高温段晶化时间、水硅比与氟离子对MOR膜的形貌、结晶度和膜层厚度产生显著影响,并影响MOR膜渗透气化分离性能;在高温段(150 ℃)和低温段(120 ℃)的晶化时间分别为 18和 6 h,在水硅比为 60且含氟离子体系中所制备的 MOR膜的性能最佳,其对质量分数50%的乙酸水溶液的渗透通量和分离系数分别为1.45 kg·m^-2·h^-1和1 008。     

三氟丙基修饰的二氧化硅膜制备、氢气分离及其水热稳定性能

以三氟丙基三甲氧基硅烷(TFPTMS)和正硅酸乙酯(TEOS)作为前驱体,通过溶胶-凝胶法制备三氟丙基修饰的SiO2膜材料,研究了三氟丙基修饰对膜材料孔结构和疏水性的作用、疏水膜材料的氢气渗透和分离性能以及水热稳定性能。结果表明三氟丙基修饰后的膜材料仍保持良好的微孔结构,孔径狭窄分布在0.45~0.7 nm之间。修饰后膜材料疏水性明显提高,当nTFPTMS/nTEOS=0.6时,对水的接触角达到(102.7°±0.1°)。H2在修饰后膜材料的输运遵循微孔扩散机理,在300℃时,H2的单组份渗透率达到4.77×10-7mol.m-2.s-1.Pa-1,H2/CO2的理想分离系数以及双组份分离系数分别达到6.99和6.93,均高于其Knudsen扩散分离因子。在200℃水蒸气物质的量含量为5%的环境中陈化220 h后,H2的单组份渗透率仅在前3 h有轻微下降,然后基本保持不变,说明三氟丙基修饰的SiO2膜具有良好的水热稳定性。     

Al3+掺杂对Li2FeSiO4结构和电化学性能影响的研究

以CH₃COOLi·2H₂O、C₆H₈O₇·H₂O、FeC₆H₅O₇·5H₂O、Al₂(SO₄)₃·18H₂O和C₈H₂₀O₄Si为起始原料,采用水热辅助溶胶凝胶法及二次煅烧合成了Li₂Fe_1-xAl_xSiO₄/C(x=0.00、0.01、0.03、0.05)正极材料。用IR、XRD、FE-SEM、EDS等方法对材料的晶体结构进行了表征,用ZetaPAL粒度分析仪测量了其粒径分布范围,用SQUID(超导量子干涉仪)测定了样品的磁性,用恒流充/放电对其电化学性能进行了测试。结果表明：n_乙酸锂∶n_柠檬酸=4∶1、掺Al³⁺量为3%,80 ℃回流24 h,350 ℃恒温煅烧5 h,700 ℃恒温13 h,所得试样颗粒集中分布在150 nm左右且未出现团聚。在0.1C(16 mA·g^-1)、0.2C、0.5C下的首次放电比容量为127 mAh·g^-1、103.6 mAh·g^-1和91 mAh·g^-1,15次循环后无明显衰减,具有很好的循环稳定性。     

模板分子诱导的微孔镧系-2-羧基肉桂酸超分子配合物的合成与结构

由水热法合成了2个微孔镧系超分子配合物[Ln(CCA)(OH)(phen)(H₂O)]_n·n(phen)·nH₂O(Ln=Yb, 1;Er, 2;H₂CCA=2-羧基肉桂酸;phen=1, 10-菲啰啉), 并用元素分析、IR及X-射线单晶衍射对其进行了表征。晶体结构研究表明, 2个配合物都是由配体2-羧基肉桂酸连接而形成的一维双链结构, 该链状结构通过氢键和π-π堆积作用扩展为具有微孔结构的超分子。1, 10-菲啰啉在微孔结构的形成过程中起到了模板剂的作用。     

间歇式水热合成制备丝光沸石膜及其异丙醇脱水应用

采用市售廉价大孔α-Al₂O₃管作为基质材料，通过热浸渍法在管外表面涂敷晶种，随后在无模板剂体系下，利用新型的间歇式水热合成法制备丝光沸石膜。对比了传统加热和间歇式加热对丝光沸石膜形貌、结构及渗透蒸发异丙醇脱水分离性能的差异。考察了合成液中Na₂O/SiO₂、SiO₂/Al₂O₃和NaF/SiO₂物质的量之比在间歇式水热合成下对丝光沸石膜的影响。研究结果表明，当合成液中Na₂O/SiO₂、SiO₂/Al₂O₃和NaF/SiO₂物质的量之比分别为0.24、16.7和0.25时，制备的丝光沸石膜渗透蒸发异丙醇脱水分离性能最佳，在75℃下，对异丙醇/水(9∶1，w/w)的渗透通量达5.60 kg·m^-2·h^-1，水对异丙醇的分离因数大于10 000。     

碳酸盐共沉淀法可控制备超高倍率锂离子电池正极材料LiNi1/3Co1/3Mn1/3O2

采用碳酸盐共沉淀法通过调节NH₃·H₂O用量来实现可控制备超高倍率纳米结构LiNi_1/3Co_1/3Mn_1/3O₂正极材料。NH₃·H₂O用量会对颗粒的形貌、粒径、晶体结构以及材料电化学性能产生较大的影响。X射线衍射（XRD）分析和扫描电镜（SEM）结果表明,随着NH₃·H₂O用量的降低,一次颗粒形貌由纳米片状逐渐过渡到纳米球状,且n_NH3·H2O：（n_Ni+n_Co+n_Mn）=1：2样品晶体层状结构最完善、Li⁺/Ni²⁺阳离子混排程度最低。电化学性能测试结果也证实了n_NH3·H2O：（n_Ni+n_Co+n_Mn）=1：2样品具有最优异的循环稳定性和超高倍率性能。具体而言,在2.7~4.3 V,1C下循环300次后的放电比容量为119 mAh·g^-1,容量保持率为81%,中值电压基本无衰减（保持率为97%）。在100C（18 Ah·g^-1）的超高倍率下,放电比容量还能达到56 mAh·g^-1,具有应用于高功率型锂离子电池的前景。此NH₃·H₂O比例值对于共沉淀法制备其他高倍率、高容量的正/负极氧化物材料具有一定的工艺参考价值。     

刚性双(三氮唑)和羧酸混合配体构建的两种金属有机骨架材料及其在CO2环加成反应中的催化性质

通过酸碱混合配体策略合成了 2 例含刚性双三氮唑配体的金属有机骨架(MOF)材料：{[Zn₂(L)(TP)₂(H₂O)·H₂O]}_n (1)和[Zn(L)(HTMA)]_n (2),其中L=4,4''-(3,3''-dimethyl-(1,1''-biphenyl)-4,4''-diyl)bis(4H-1,2,4-triazole),H₂TP=对苯二甲酸,H₃TMA=1,3,5-均苯三甲酸。用单晶 X 射线衍射表征其结构。结构分析表明,MOF 1显示出 3,6-双节点的二维结构,其拓扑符号为(4²·6)₂(4⁸·6⁶·8),MOF 2呈现为经典的 sql二维拓扑结构。在温和条件下,2对 CO₂与环氧化物的环加成反应具有优异的催化活性,且重复使用至少3次后仍然保持其催化性能。     

刚性双(三氮唑)和羧酸混合配体构建的两种金属有机骨架材料及其在CO2环加成反应中的催化性质

通过酸碱混合配体策略合成了 2 例含刚性双三氮唑配体的金属有机骨架(MOF)材料：{[Zn₂(L)(TP)₂(H₂O)·H₂O]}_n (1)和[Zn(L)(HTMA)]_n (2),其中L=4,4''-(3,3''-dimethyl-(1,1''-biphenyl)-4,4''-diyl)bis(4H-1,2,4-triazole),H₂TP=对苯二甲酸,H₃TMA=1,3,5-均苯三甲酸。用单晶 X 射线衍射表征其结构。结构分析表明,MOF 1显示出 3,6-双节点的二维结构,其拓扑符号为(4²·6)2(4⁸·6⁶·8),MOF 2呈现为经典的 sql二维拓扑结构。在温和条件下,2对 CO₂与环氧化物的环加成反应具有优异的催化活性,且重复使用至少3次后仍然保持其催化性能。     

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.