分子量分布对等规聚丙烯卷绕丝织构形成的影响

本文研究了分子量分布对聚丙烯卷绕丝结构和性能的影响。结果表明,聚丙烯树脂中的高分子量尾端对卷绕丝的结构有明显影响。在通常的纺丝条件下,用控制降解的聚丙烯树脂纺得的卷绕丝具有低取向的次晶结构;而在相同的粘均分子量和纺丝条件下,高分子量尾端的存在使聚丙烯易于在纺丝线上生成结晶性较高的α-晶型,卷绕丝的取向也随高分子量尾端而显著增大。高分子量尾端对卷绕丝结构的影响,导致卷绕丝牵伸性能和成品纤维力学性能变差。     

细旦尼龙6纤维加工过程中的晶型转化行为

通过引入富镧稀土化合物等添加剂,成功实现了细旦尼龙6纤维的熔融纺丝．考察了在纺丝卷绕成型以及牵伸过程中尼龙6纤维的晶型变化．借助XRD和FT－IR等研究手段,发现尼龙6在纺丝过程中可以生成亚稳态的B晶型晶体．这种β晶型经过沸水处理后很容易转化为α晶型,而γ晶型尼龙6经沸水处理后不发生相转变．因此可以通过沸水热处理的方法区分尼龙6的β和γ晶型．在纤维的卷绕过程中,当熔体拉伸倍数较高时,尼龙6可能产生β晶型;当熔体拉伸倍数较低时,则以γ晶型为主．在纤维的牵伸过程中,γ晶型经过β晶型中间态向α晶型相转变．上述结果对于指导改进细旦尼龙6纤维的加工工艺以及提高产品性能有指导意义．     

钇与亚胺基二乙酸配合物的合成及晶体结构

合成了钇与亚胺基二乙酸的配合物，用Ｘ射线衍射法测定了配合物的单晶结构，化学式为［Ｙ２｛Ｈ２Ｎ（ＣＨ２ＣＯＯ）２｝（Ｈ２Ｏ）４］（ＣｌＯ４）２·１．２５Ｈ２Ｏ。晶体属三斜晶系，Ｐ１↑－空间群。晶胞参数：ａ＝０．９２５４（１）ｎｍ，ｂ＝０．９９２２（１）ｎｍ，ｃ＝１．０６５８（２）ｎｍ，α＝７１．４８１（１０）°，β＝７７．９５０（１０）°，γ＝６５．３５０（１０）°，Ｖ＝０．８４０１（２）＾３，Ｚ＝     

关于超高分子量聚丙烯超拉伸膜的结构性能的研究——Ⅱ.形态结构变化对力学性能的影响

 用X-射线衍射、动态力学测定等手段研究了不同拉伸倍数的超高分子量聚丙烯薄膜的力学性能的变化.以X-射线衍射法并基于串联力学模型的假设得到的各样品的表观晶区模量E_c^app约为34-38GPa.样品模量E_b随拉伸倍数增加而逐渐增大,其变化趋势与非晶区取向因子的变化相类似,说明非晶区取向是左右样品模量的重要因素.室温下,69倍拉伸样品的模量为27GPa,约为表观结晶模量的3/4,且其值在-150-160℃的温度范围内没有急剧变化,说明超拉伸明显改善了材料的力学性能及热稳定性.在各拉伸样品中,考虑伸直链结晶生成的可能性,利用并串联力学模型对伸直链结晶的体积分数做了估算,并对X-射线衍射法所得表观结晶模量进行了修正,认为室温下聚丙烯的真正晶区模量约为47GPa.     

FRS—XRSA表征双轴取向PET的结晶度

全倒易空间Ｘ－射线散射理论分析（ＦＲＳ—ＸＲＳＡ）是研究与表征择优取向高聚物结晶度与取向分布的一种新方案，它可以解决粉沫法测定结晶度时取向试样难以消取向的困难，测定拉伸和回复过程中正在形变的取向试样的结晶度．在以前的工作中，对双轴取向的薄膜，仅进行了幅度β＝０°（ＭＤ）与９０°（ＴＤ）两个轴向，△α＝１０°的ＸＲＳ测定，这样推得的结晶度事实上是ＭＴ双轴ＸＲＳ的结晶度，即ＭＴ－ＸＲＳ结晶度Ｘ，这种处理包含着ＸＲＳ沿ＭＴ方向作均匀分布的近似．本文为了澄清这一问题，作了下述三点改进：第一，利用ＦＲＳ中ＸＲＳ的强度分布，内插计算αｉ；，βｉ＝０°～９０°，△βｉ＝１０°的ＸＲＳ，由此求得较符合理论要求的ＦＲＳ－ＸＲＳ结晶度Ｘ；第二，进行了ＦＲＳ－ＸＲＳ的极角因子ｃｏｓαｉ；校正；第三，合理地处理了当极角αｉ＝９０°时出现奇点的困难．结果较合理．同时亦获得了晶粒度在ＦＲＳ中的分布情况．     

Nd34Fe60O6合金的显微组织研究

采用扫描电镜、俄歇探针、Ｘ射线衍射、热磁分析、热磁分析等方法深入研究了Ｎｄ３４Ｆｅ６０Ｏ６合金的显微组织。发现合金的平衡组织由Ｎｄ２Ｆｅ１７主相、含氧的富钕相和一个Ｎｄ－Ｆｅ－Ｏ三元铁磁性相（记为Ｔ１相）组成。该相在８４０℃通过Ｎｄ２Ｆｅ１７相与富Ｎｄ液相的包晶反应形成。它的成分约为Ｎｄ３４Ｆｅ５０Ｏ１０，居里温度为１８０℃。其Ｘ射线衍射峰可用点阵常数α＝０．７７１ｎｍ、ｃ＝２．２２８ｎｍ的四方晶     

K_3Sb_3P_2O_（14）·5H_2O的水热合成与表征

利用水热晶化法合成了磷锑酸钾Ｋ３Ｓｂ３Ｐ２Ｏ１４·５Ｈ２Ｏ，并通过ＸＲＤ、３１ＰＭＡＳＮＭＲ、ＩＲ、ＤＴＡ－ＴＧ及组成分析等多种手段对其进行了表征。该化合物属六方晶系，晶胞参数为：ａ＝０．７１３７７ｎｍ，ｂ＝０．７１３７７ｎｍ，ｃ＝３．０８０４７ｎｍ，α＝９０°，β＝９０°，γ＝１２０°，具有层状结构，钾离子具有可交换性。     

含质子柠檬酸氧钒（V）配合物中间体的合成和晶体结构

合成了含质子柠檬酸氧钒（Ｖ）配合物中间体ＮａＫ３［ＶＯ２（Ｈｃｉｔ）］２·７Ｈ２Ｏ，用红外光谱和Ｘ射线衍射进行了结构表征。结果表明：晶体属单斜晶系，Ｐ２１／ｎ空间群。晶胞参数ａ＝１．１２５８（２）ｎｍ，ｂ＝１．５７７４（３）ｎｍ，ｃ＝１６５５９（１）ｎｍ，β＝９８．５６８（９）°，Ｖ＝２．９０８（１）ｎｍ＾３，Ｚ＝４，Ｄｃ＝１．８５１ｇ·ｃｍ＾－３，Ｆ（０００）＝１６４０，μ（Ｃｕ Ｋα）＝１０４     

三羰基环戊二烯基钼负离子与1，3－二卤丙烷的反应

三羰基环戊二烯基钼负离子与１，３－二卤丙烷在一缩二乙二醇二甲醚介质中反应，生成环卡宾配合物ＣｐＭｏＸ（ＣＯ）＿２ＣＯ（ＣＨ＿２）＿２ＣＨ２（Ｘ＝Ｂｒ，Ｉ）．硅桥连双环戊二烯基三羰基钼负离子与１，３－二卤丙烷顺利地进行类似反应，生成相应的硅桥连双［环卡宾钼配合物］──Ｅ［Ｃ＿５Ｈ＿４ＭｏＸ（ＣＯ）＿２］ＣＯ（ＣＨ＿２）＿２ＣＨ＿２］＿２（Ｅ＝Ｍｅ＿２Ｓｉ，Ｍｅ２ＳｉＳｉＭｅ＿２，Ｍｅ２ＳｉＯＳｉＭｅ＿２）．化合物硅氧硅桥联二茂二钼环卡宾配合物１１的晶体结构经Ｘ射线衍射测定，晶体属三斜晶系，Ｐ１空间群，晶体学数据：ａ＝０．８１８８（１）ｎｍ，ｂ＝１．０４５（３）ｎｍ，ｃ＝２．３２５２（４）ｎｍ，α＝９４．１４（２）°，β＝９４．０９（１）°，γ＝１０２．４８（２）°，Ｖ＝１．９３０６ｎｍ￣３，Ｚ＝２，Ｄ＿ｃ＝１．８５４ｇ／ｃｍ￣３。     

PP—g—MAZn离聚物的固相法合成与表征

以ＤＣＰＯ为引发剂，将ＰＰ粉末通过固相法与马为酸锌发生接枝反应，合成不同接枝率的ＰＰ－ｇ－ＭＡＺｎ离聚物。考察反应温度，引发剂浓度，单体的用量对接枝率的影响，研究表明，（１）ＰＰ－ｇ－ＭＡＺｎ离聚物的ＦＴＩＲ图中，１５４０ｃｍ＾－１－１６４３ｃｍ＾－１之间出现宽的峰，说明ＭＡＺｎ与ＰＰ发生了接枝反应；（２）ＰＰ－ｇ－ＭＡＺｎ的ＷＡＸＤ谱中在２θ＝１０．６°，３１．２°，３３．２°，处有衍射峰，表明     

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%.     

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.     

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.     

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.     

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.     

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.     

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.