均甲甲苯改性沥青的化学结构特征

平均结构参数分析法是沥青类复杂分子体系化学结构的一种有效方法。通过分析比较热处理改性沥青和均甲甲苯改性沥青在化学结构上的不同,发现均甲甲苯改性沥青中有机分子的分子量较大,但氢含量较高,芳香度较小,主要表现为脂肪环结构的增多和甲基取代基的大量引入。氢转移、质子化、亚甲基桥的形成可能是导致这些结构特征的主要原因。     

均四甲苯和四氢萘亚甲基齐聚物中间相转化行为及其机理研究

利用动态热台显微镜法对比研究了两种合成亚甲基齐聚物（均四甲苯齐聚物和四氢萘齐聚物）的中间相形成及其转化行为，发现二者均可在中温热解过程中形成中间相小球并转化为大域体中间相织构，但均四甲苯齐聚物中间相形成及转化温度（３６０￣３９０℃）远低于四氢萘齐聚物（５００￣５３０℃）。通过进一步对比考察两种原料在中间相转化前后的结构变化，认为引起该热解行为差异的结构原因在于：均四甲苯齐聚物中大量的甲基含量和拥挤     

重质稠环芳烃的固体核磁共振光谱研究

以固体核磁共振光谱为主要分析手段,比较研究了两种合成中间相沥青吡啶不溶组分的结构。结果表明：均四甲苯基中间相沥青吡啶不溶组分具有较低的芳香度和缩合度,富含甲基和环烷结构,分子呈渺位结合实际合构型;与此相反,四氢萘基中间相沥青则呈现很高的芳香度和缩合度,芳环上仅带有一些甲基取代基,平均分子为完全迫位缩合构型,造成这种结构差异的原因在于前驱齐聚物的结构及缩聚程度的不同。     

芳香环上氢质子的化学位移最大差值与其芳香性的关系

利用化合物的氢质子的核磁共振谱图来研究化合物的分子结构,现在已经成为实验室中常规分析方法之一.有机化合物分子中氢质子的化学位移值除了和实验条件有关外,主要决定于化合物的分子结构.也就是说,是由试样分子中氢质子的结构环境决定的.因此,人们把核磁共振谱中的化学位移值和分子的红外光谱峰值都看成是一个化合物分子的“指纹”数     

煤液化沥青分析表征及结构模型

对从煤液化残渣中萃取出的沥青类物质进行了固体13C-CP/MAS NMR分析、元素分析、红外光谱分析(FT-IR)和光电子能谱(XPS)分析,得到煤液化沥青的芳香结构单元信息及相关结构参数信息。结果表明,煤液化沥青芳香桥碳与周碳之比为0.115,芳香碳原子的存在形式以苯结构为主;脂肪结构多以甲基和环状亚甲基形式存在;氧主要以羰基、酯基的形式存在;氮主要以吡咯的形式存在。利用结构参数和分析表征结果构建了煤液化沥青的大分子结构模型,并运用13C-NMR预测软件ACD/CNMR Predictor计算了煤精制沥青大分子结构模型的13C化学位移。根据计算结果对大分子结构模型进行了修正,获得了与实验谱图吻合较好的大分子结构模型。     

β-酞酰亚腔基-α-甲基丙酸甲酯的结构分析

为研究取代基对Michael式加成反应的影响,在相转移催化条件下酞酰亚胺与α-甲基丙烯酸甲酯进行加成反应,通过1H NMR、IR、MS和元素分析对产物结构进行分析,确证其为β-酞酰亚胺基-α-甲基丙酸甲酯;分析了所形成的手性碳结构对邻位亚甲基核磁共振氢谱的影响,并提出了产物分子的碎裂机理.     

镍铁氢化酶活性中心的结构、催化机理及化学模拟

镍铁氢化酶具有催化分裂重组氢分子的功能，由于其独特的活性中心结构和催化性能及方便、廉价利用氢能源的前景，引起生物学家和化学家的关注，他们对镍铁氢化酶活性中心结构、催化机理及化学模拟做了深入细致研究，本文对此做系统概述和总结。     

β-酞酰亚胺基-α-甲基丙酸甲酯的结构分析

为研究取代基对Michael式加成反应的影响，在相转移催化条件下酞酰亚胺与α-甲基丙烯酸甲酯进行加成反应，通过^1H NMR、IR、MS和元素分析对产物结构进行分析，确证其为β-酞酰亚胺基-α一甲基丙酸甲酯；分析了所形成的手性碳结构对邻位亚甲基核磁共振氢谱的影响，并提出了产物分子的碎裂机理。     

超声波处理对加氢反应前后沥青质单元分子结构的影响

以胜利减渣和沙轻减渣为原料,研究了超声波处理对加氢反应前后沥青质单元分子结构的影响,并结合1H-NMR数据、沥青质单元分子参数变化和红外光谱分析等结果,用Chem Bio Draw Ultra 2012模拟出不同条件下两种沥青质单元分子的结构。结果表明,超声波处理减少了沥青质的缔合数,使沥青质单元分子发生开环反应和脱烷基侧链反应加剧,改变了沥青质单元分子的结构,对加氢后沥青质单元分子的结构和组成产生重要影响。沥青质单元分子模型可形象体现超声波处理对加氢反应前后沥青质单元分子化学结构的影响,有助于在分子水平上解释超声波处理影响沥青质单元分子的原因。     

超声波处理对加氢反应前后沥青质单元分子结构的影响

以胜利减渣和沙轻减渣为原料,研究了超声波处理对加氢反应前后沥青质单元分子结构的影响,并结合¹H-NMR数据、沥青质单元分子参数变化和红外光谱分析等结果,用Chem Bio Draw Ultra 2012模拟出不同条件下两种沥青质单元分子的结构。结果表明,超声波处理减少了沥青质的缔合数,使沥青质单元分子发生开环反应和脱烷基侧链反应加剧,改变了沥青质单元分子的结构,对加氢后沥青质单元分子的结构和组成产生重要影响。沥青质单元分子模型可形象体现超声波处理对加氢反应前后沥青质单元分子化学结构的影响,有助于在分子水平上解释超声波处理影响沥青质单元分子的原因。     

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.     

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.     

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.     

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.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

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.