溶致性液晶高分子P（BZT—BZO）的合成性能与结构研究

在多聚磷酸介质中,用共缩聚的方法合成了苯撑苯并二噻唑(BZT)和苯撑并二恶唑(BZO)的共聚物P(BZT-BZO)。特性粘数测定结果表明所得共聚物分子量约为 20,000。用红外光谱及X-光衍射法测定了共聚物结构,表明共聚物是有两均聚物的结构的加和性。共聚物的多聚磷酸溶液具有搅拌乳光现象,表示该共聚物亦具有溶致性液晶高分子特征。由液晶相成膜的共聚物薄膜具有优异的力学性能及热稳定性。     

多聚磷酸/乙酸体系对PBO纤维表面改性的研究

采用多聚磷酸/乙酸体系并结合偶联剂处理方法对PBO纤维表面进行化学改性,采用扫描电镜和液滴形状法对处理前后纤维表面形态结构和纤维表面亲水性进行了表征,通过单丝拔出试验测定了改性前后PBO纤维与环氧树脂基体的界面剪切强度。利用X光电子能谱和热重分析等方法对纤维表面元素组成和热稳定性进行了分析。研究发现,多聚磷酸/乙酸体系偶联剂的方法改性后PBO纤维表面亲水性明显增强,与水的接触角从大于90°下降到42.8,°PBO纤维/环氧树脂的界面剪切强度较未处理样品提高了45%。     

聚苯撑苯并二噻唑(PBT)的耐热性和液晶性研究

PBT溶于甲基磺酸(MSA)和多聚磷酸(PPA)等强酸溶剂中时能形成液晶。用TGA法测定了PBT在氮气和空气中的热分解温度,分别高达690℃和585℃。计算了PBT在氮气中的分解活化能为161 kJ/mol。测定了PBT-MSA体系液晶的退偏振光强度-温度谱和浓度-温度二元液晶区域相图,并发现8％的PBT-PPA体系表现出特殊的退偏光强度-温度特性。液晶和PBT固体的X-衍射图表明液晶状态下沉积的薄膜保持了液晶态的结构,固体小角光散射的H_v图表明非液晶态下沉积的PBT薄膜有球晶结构。     

溶致性液晶高分子聚苯并■唑的合成和结构与性能研究

用对羟基苯甲酸甲酯（乙酯）为原料，合成了自缩聚型单体４ 羟基 ３ 胺基苯甲酸盐酸盐，在多聚磷酸介质中经溶液缩聚，制得高分子量的聚苯并唑（ＡＢＰＢＯ），在聚合后期观察到明显的溶致性液晶高分子所特有的搅拌乳光现象，经推膜及干喷湿纺技术得到了ＡＢＰ ＢＯ的薄膜和纤维．在甲基磺酸溶液中测定了ＡＢＰＢＯ的特性粘数，用Ｘ ｒａｙ平板照相及Ｘ ｒａｙ衍射、ＦＴＩＲ、ＴＧＡ、动态粘弹谱仪等测定和研究了ＡＢＰＢＯ薄膜和纤维的结构和性能，抗张强度为１５５ＧＰａ，抗张模量为９０ＧＰａ，在氮气中起始分解温度为６５７３℃．结果表明ＡＢＰＢＯ是一种高性能的半刚性的溶致性液晶高分子材料     

液晶高分子聚苯撑苯并二噁唑的合成、结构与性能

本文以间苯二酚为原料,合成了缩聚单体4,6-二胺基1,3-间苯二酚盐酸盐。在多聚磷酸介质中与对苯二甲酸经分段升温缩聚得聚苯撑苯并二噁唑(PBZO).用元素分析法,X-光衍射法、X-光平板照相、FTIR和C~(13)-NMR研究了PBZO的结构.测定了PBZO/MSA体系的特性粘数。测定了PBZO的力学性能和热稳定性。结果表明PBZO是继PBZT后又一种新型的高性能液晶高分子材料。     

溶致性液晶高分子聚苯并恶唑的合成和结构与性能研究

用对羟基苯甲酸甲酯为原料，合成了自缩聚型单体４－羟基－３胺基苯甲酸盐酸盐，在多聚磷酸介质中经溶液缩聚，制得高分子量的聚苯并恶唑，在聚合后期观察到明显的溶致性液晶高分子所特有的搅拌乳光现象，经携膜及干喷湿纺技术得到了ＡＢＰ－ＢＯ的薄膜和纤维。     

2-取代苯并眯唑合成工艺的改进

以邻苯二胺和有机酸为原料,在磷酸和多聚磷酸混合酸的催化下合成了四种2-取代苯并咪唑化合物。利用红外光谱、核磁氢谱、熔点测定等方法对产物进行了结构表征。讨论了反应温度、催化剂用量对收率的影响。该合成工艺较原有的工艺得以完善,收率有较大提高。     

纤维素基聚合物液晶溶液的发展、现状及展望

使用液晶溶液纺丝可以制得高强度、高模量的纤维.经大量研究发现,作为环保可再生的资源,纤维素及其衍生物在一定浓度和一部分合适的溶剂体系中能够形成各向异性溶液.但目前,纤维素基聚合物的液晶溶液纺丝并没有成功实现工业化.文章综述了纤维素基聚合物的液晶理论,其液晶溶液的发展过程与现状及独特的流变行为,并展望在少数能直接溶解纤维素并形成液晶溶液的溶剂体系中,磷酸是一种合适的溶剂体系,有很大的发展和应用空间.     

固相微萃取-气相色谱法测定水中的甲基膦酸

报道了应用固相微萃取-气相色谱法测定水中甲基磷酸的方法,研究了不同固相微萃取纤维、萃取温度和时间、解吸时间、pH值等萃取条件和衍生化温度和时间、衍生化程序等衍生条件对测定效果的影响;结果表明该法简便、快速、有效,其检出限为0．03mg/L。     

流动注射化学发光法测定针剂中的头孢唑啉钠

在多聚磷酸介质中,用KMnO4氧化头孢唑啉钠能产生强化学发光,据此本文建立了一种流动注射化学发光测定头孢唑啉钠的新方法.化学发光信号ICL与头孢唑啉钠质量浓度ρ在0～350 mg/L范围内呈良好线性关系,回归方程为ICL=1.415＋0.959ρ（r=0.9999,n=11）,方法的检出限为1.6 mg/L,相对标准偏差为0.6%（n=11,ρ=50.0 mg/L）.用本法对针剂中头孢唑啉钠进行测定.并初步探讨了该化学发光反应的发光机理.     

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.     

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.     

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.     

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.     

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.     

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.     

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.