聚甲基丙烯酸甲酯－聚四氢呋喃两嵌段共聚物／聚四氢呋喃共混体系的相容性和结晶行为

报道了对嵌段共聚物结晶型共混体系结晶行为的研究．通过对聚甲基丙烯酸甲酯－聚四氢呋喃两嵌段共聚物／聚四氢呋喃共混体系的研究，我们发现１．微相分离结构的存在，可使相容的这类体系形成多种特殊的结晶形态；２．共混体系的相容性可以方便地由其结晶行为来判断；３．共混体系中共聚物的结晶能力显著提高．这些特点都明显不同于一般的聚合物共混体系．     

含间位取代苯基聚醚酮酮的结晶与晶体结构研究

通过差示扫描法（ＤＳＣ）及广角Ｘ 射线衍射（ＷＡＸＤ）技术研究了含间位取代苯基聚醚酮酮（ＰＥＫｍＫ）的结晶行为与晶体结构．Ｘ 射线结果表明，从熔融态及玻璃态结晶时，ＰＥＫｍＫ只有一种晶型，其晶胞参数为：ａ＝０７６７２ｎｍ，ｂ＝０６１４９ｎｍ，ｃ＝１５９９ｎｍ．ＤＳＣ结果表明，ＰＥＫｍＫ热分析曲线都出现了熔融双峰，低熔融峰（ＤＯＷｎ）热焓占总热焓４～７％，它源于初始结晶形成的同一晶型不同厚度片晶．低熔融峰在２５０℃以上结晶转化成高熔融峰（Ｉ），ＰＥＫｍＫ平衡熔点为２９５℃     

聚合物结晶成核剂作用的表征方法的比较和研究

用聚合物的等速降温过程的结晶温度，等温结晶过程的半结晶时间（ｔ１／２）或结晶速度常数（Ｋ），结晶过程的晶核密度或球晶尺寸大小和聚合物结晶成核界面自由能（σσｅ或σｅ）大小等方法描述了碳酸钙、对苯二甲酸、苯甲酸钠对聚丙烯成核结晶过程的影响．通过对不同方法的比较，结果表明不同方法是从不同角度来反映助剂对聚合物成核结晶过程的影响，聚合物结晶温度的高低和等温结晶过程的半结晶时间或结晶速度常数是描述聚合物整体结晶速度的参数；而聚合物结晶过程中晶核密度或结晶完了时聚合物球晶尺寸，和聚合物结晶成核界面自由能大小与聚合物的成核难易程度直接相关，是判断聚合物结晶成核速度的方法．但不同方法之间存在一定的相关性，所以用不同方法测定的结果之间有较好的可比性，可根据具体条件选用一种方法．多种方法的配合使用可以较全面的了解成核剂的作用．     

测定高聚物动力学结晶能力的非等温DSC方法

研究了从非等温ＤＳＣ结晶曲线计算高聚物动力学结晶能力的方法．从高聚物非等温结晶动力学微分方程出发导出了计算高聚物动力学结晶能力的新方程．以含有不同催化剂的聚对苯二甲酸乙二酯为例，对其结晶进行了测试与计算．发现合理地选定最快结晶速率温度是计算动力学结晶能力的关键．本方法所得动力学结晶能力能正确反映高聚物的整体结晶信息     

HE－1型催化剂异相聚合乙烯结晶性能研究 Ⅱ．超高分子量PE结晶行为

用小角Ｘ－射线散射，广角Ｘ－射线衍射，差示扫描量热法，研究了ＨＥ－１型钛系催化剂异相聚合超高分子量聚乙烯的稀溶液的结晶和熔融结晶的熔点，熔化热，结晶度，长周期，晶区厚度和非昌区厚度随分子量与结晶温度的关系．并着重讨论了熔融结晶和初生态结晶的不同过程机理．结果表明：ＵＨＭＷＰＥ稀溶液结晶的结晶度（Ｘｃ％），长周期（Ｌ）和晶区厚度（Ｌｃ）与分子量Ｍｗ无关，随结晶温度升高而增加，非晶区厚度（Ｌａ）与分子量和结晶温度均无关，熔点Ｔｍ随分子量增大稍有升高．熔融结晶样品长周期与分子量无关，却和结晶温度和时间有关．其结晶度和晶区厚度随分子量增大而下降，非昌区厚度和熔点均随分子量增大而增大，初生态粉末中没发现长周期，却发现有较高熔点．     

含间苯连接的聚醚醚酮酮的等温结晶过程和形态结构

用透射电子显微镜和电子衍射方法研究了含间苯连接的聚醚醚酮酮（PEEKmK）溶液浇铸薄膜的等温结晶过程和形态结构．结果表明，PEEKmK无论从玻璃态结晶还是从熔体结晶均能形成2种不同取向的结晶形态结构，即平放片晶和侧放片晶；前者c轴垂直于膜平面，后者c轴平行于膜平面．其结晶发展过程为先形成平放单晶状片晶，随着时间的增长，在单晶上开始生长侧放片晶，逐渐发展形成球晶，最终形成2种不同取向的单晶和球晶共存的结晶形态结构．     

热处理对尼龙1010结构影响研究

采用ＷＡＸＤ，ＳＡＸＳ方法研究了热处理对尼龙１０１０聚集态结构的影响．结果表明，在温度为１７５℃左右对样品进行退火处理可获得较完善的结晶．利用Ｗｃ．ｘ~Ｔ关系曲线外推法得到尼龙１０１０样品的Ｔｇ大约为５８℃．根据一维电子密度相关函数法求得了系列样品在所研究条件下的结晶片层厚，过渡层厚，长周期和结晶非晶相间的密度差．得到了不同退火条件尼龙１０１０样品的结晶相密度ρｃ．     

盐卤硼酸盐化学ⅩⅩⅥ．MgO·2B_2O_3－18％MgCl_2－H_2O产过饱和溶液结晶动力学研究

ＭｇＯ·２Ｂ２Ｏ３－１８％ＭｇＣｌ２－Ｈ２Ｏ过饱和溶液于２０℃恒温静置，其结晶过程分为两个阶段．第一阶段结晶析出三方硼镁石（ＭｇＯ·３Ｂ２Ｏ３·７．５Ｈ２Ｏ），第二阶段析出章氏硼镁石（ＭｇＯ·２Ｂ２Ｏ３·９Ｈ２Ｏ）．未得到多水硼镁石和库水硼镁石．探讨了两种析出团相的结晶机理并拟合出结晶动力学方程．结果表明，两种固相结晶机理均为多核表面反应控制生长．     

结晶条件对聚丙烯晶胞参数影响的研究

研究了不同方式和条件下形成的等规聚丙烯结晶的晶胞参数，用步进扫描测定试样的宽角Ｘ 射线衍射，用广义逆矩阵法编的计算机分峰程序和晶胞参数拟合计算程序对测定结果进行计算和数据处理．结果表明结晶方式和条件对晶胞参数的影响是明显的，结晶密度依以下次序减小：１４５℃结晶５ｈ＞初生态＞熔融后冰水淬火＞溶液结晶．用差示扫描量热（ＤＳＣ）考察了这些试样的热行为，表明熔融吸热峰Ｉ与结晶密度相关．     

流动注射—结晶紫—磷钼杂多酸离子缔合体系光度法测定水中痕？…

在一定的酸度条件下，结晶紫与磷钼杂多酸离子缔合物的流动注射分光光度法可直接测定痕量磷。灵敏度高，重现性和选择性好。水中常见离子不干扰痕量磷的测定，工作曲线的线性范围为０￣５００μｇ·Ｌ＾－１的磷，检出下限达１．０μｇ·Ｌ＾－１，以１２０ｈ＾－１采样频率，对各种天然水样进行测定，回收率为９２．５％￣１０５．０％，相对标准偏差为０．１％￣６．７％。     

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.