聚芳醚酮类聚合物晶体结构醚酮等效性的研究

半结晶的聚芳醚酮类聚合物 ( PAEKs)因其性能优异而在机械、航天等高技术领域中得到广泛应用 .有关其晶体结构的研究亦有许多文献报道[1～ 11] ,而醚基与酮基在晶体结构方面是否等效一直存在争议 .虽然醚酮等效性的观点已被广泛接受 [4～ 8] ,但对于聚合物主链中含联苯基团的 PAEKs的醚酮等效性的研究则复杂得多 .文献 [1 ]报道醚酮等效性在主链含有联苯基团时不再成立 .本文首次发现醚酮等效性在主链含有联苯基团时在适当条件下仍可成立 ,并对聚芳醚酮类聚合物晶体结构的醚酮等效性问题进行了系统阐述 .1　实验部分　　样品联苯聚醚酮 …     

聚醚醚酮分子结构对流动性和热性能的影响

本文用稍过量４、４’－二氯苯酮合成的聚醚醚酮（ＰＥＥＫ）样品，利用ＵＶ、ＭＩ、ＤＳＣ和ＴＧＡ等研究本氧阴离子及其相对浓度在树脂合成和加工过程中对ＰＥＥＫ分子结构和性能的影响．结果表明：苯氧阴离子端基引起支化交联反应，且随着其相对浓度增加而增加．采用过量４、４’－二氯苯酮合成ＰＥＥＫ，不仅能控制产物的分子量，而且有利于抑制支化交联反应，提高ＰＥＥＫ的流动性和热稳定性．本文还初步探讨了ＰＥＥＫ支化反应机理和支化高分子热分解机理．     

AM1半经验方法研究苯环在PEEK模型分子内的运动

本文使用ＡＭ１半经验量子化学计算研究了苯环在ＰＥＥＫ链内的运动，结果表明，不论以醚桥相连的苯环或以酮桥相连的苯环均优先取与骨架面成３０°的倾斜位置，晶态ＰＥＥＫ中苯环的取向主要是链内相互作用的结果，求得了３种可能的大幅度苯环运动及其相应的活化能，并与γ－松弛的实验结果进行了比较。     

有机化学试题选登

有机化学试题选登一、完成下列反应二、合成１．自苯合成２－苯基吲哚２．自硝基苯合成６，６’联喹啉３．自丙二酸二乙酯及必要试剂合成２－甲基－４－异丙基１，３环己二酮４．自丙二酸二乙酯及必要试剂合成β－（３－环己烯基）丙酸５．自乙酰乙酸乙酯合成４－甲基－４...     

含联苯核和取代基液晶聚甲亚胺醚的合成

含联苯核和取代基液晶聚甲亚胺醚的合成张其震，薛庆斌，李小放（山东大学化学系，济南，２５０１００）关键词聚甲亚胺醚，相转移催化，双－（３－甲氧基－４－羟基苄叉）－４，４’－二亚胺基联苯，条带织构高分子液晶中聚酷胺和聚酯研究较多，聚甲亚胺醚研究较少，Ｗｏ...     

含两种不同介晶基团的半刚性共聚酯液晶态的结构研究

用Ｘ－光衍射，偏光显微镜及ＤＳＣ对含两种不同长度介晶基团４，４’－联苯二酚（Ⅰ）和对苯二甲酸二（对羟苯基）酯（Ⅱ）的系列共聚酯的液晶态进行了表征，据其液晶态中两种介晶单元的堆砌方式提出了可能的模型，这种模型很好地解释了液晶态的Ｘ－光衍射分布．     

高性能聚芳醚酮的合成与性能(Ⅰ)——对苯二酚、联苯二酚、4,4′,-二氟二苯酮三元共聚体系

聚醚醚酮(PEEK)具有突出的耐高温水解和耐辐照性能以及良好的断裂韧性,现已在核能、宇航等高技术领域得到应用。研制新型聚芳醚酮是目前十分活跃的课题。本文采用亲核取代路线,以对苯二酚、联苯二酚、4,4′-二氟二苯酮为单体合成了一系列含亚联苯结构的新型聚芳醚酮,并对基基本性能进行了测定。     

具有液晶性新型聚芳醚酮的合成与表征

通过联苯二酚(介晶基元)、取代对苯二酚(破坏结晶基元)与4,4'-二氟二苯酮的亲核取代反应合成了一系列具有液晶性的新型聚芳醚酮,采用DSC、PLM和WAXD等方法对聚合物的研究表明:联苯含量为70%时聚合物表现为向列相,联苯含量为50%时聚合物出现近晶相,在外力场作用下,向列相液晶容易形成明暗交替的条带织构.     

2,4—二甲氧基苯基荧光酮荧光熄灭法测定痕量钨

１引言荧光光度法测定钨所用的荧光酮类试剂有：二溴羟基苯基荧光酮、５’－硝基水杨基荧光酮、水杨基荧光酮等．２，４－二甲氧基苯基荧光酮（ＤＭＰＦ）自合成以来，已应用于荧光熄灭法测定钛、铁等．作者详细地研究了在混合表面活性剂（ＣＴＭＡＢ＋ＯＰ－１０）协同增敏作用下，钨与２，４－二甲氧基苯基荧光酮的荧光熄灭体系．该法显色迅速，荧光强度稳定，线性范围宽．在混合掩蔽剂ＥＤＴＡ和盐酸羟胺存在下，测定合金钢中的钨，结果满意。２实验部分２．对主要仪器与试剂９３０型荧光光度计；钨标准溶液（ｌ．００ｍｇ／Ｌ）；２，４…     

分散红掺杂高Tg聚合物母体的非线性光学性质的研究

利用具有非线性光学（ＮＬＯ）活性的分散红（ＤＲＩ）掺杂高玻璃化转变温度的酚酞聚羟基醚（ＰＨＰ）和酚酞－联苯二酚－二氯二苯酮三元共聚物（ＰＰＨＢＰ－ＤＣＢＰ ｃｏｐｏｌｙｍｅｒ），得到了两种掺杂型非线性光学材料。升温电晕极化（ＣＯＰＥＴ）表明有较高的取向和较慢松驰，并推算了极化场强度Ｅｐ和二阶非线性系数ｄ３３。     

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.     

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.     

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.     

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%).