富马酸二异丙酯—富马酸二正庚酯共聚物的合成与气体透过性能

自Bengough等用自由基引发聚合的方法首次得到了较高分子量的聚富马酸二乙酯后,有关富马酸酯(DRFs)类单体的聚合反应及其结构性能已进行了许多研究。结果表明,这类单体的聚合物在聚合反应活性、聚合物结构及性能等方面均有某些独特的性质,如聚富马酸二异丙酯(PDiPF)和聚富马酸二特丁酯(PDtBF)两种聚合物具有良好的氧氮透过性。我们曾研究十几种DRFs单体的聚合反应,得出非正烷基酯基的单体如富马酸二异丙酯(DiPF),富马     

聚反丁烯二酸酯的结构与性能

采用自由基聚合法合成了的聚反丁烯二酸二特丁酯(PDtBF)、聚反丁烯二酸二异丙酯(PDiPF)、聚反丁烯二酸二仲丁酯(PDsBF)、聚反丁烯二酸二仲戊酯(PDsAF)、聚反丁烯二酸二环已酯(PDCHF)和聚反丁烯二酸甲基异丙基酯(PMiPF)这六种不同的反丁烯二酸酯类聚合物,利用~1H-NMR、~(13)C-NMR等表征手段对上述几种聚合物的链结构进行了分析表征。利用X-射线衍射方法对聚合物的聚集态结构进行了研究,结果表明,上述几种聚合物均具有较高的分子量,并表现出很强的脆性,聚合物的分子链间距随聚合物中酯基体积的增大而增加,对聚合物的热性能等进行了初步研究。     

反丁烯二酸酯的自由基共聚反应

<正> 对反丁烯二酸酯(DRPs)类单休的均实反应研究已有许多报道。研究结果表明,所有的正烷基酯基DRFs单体,如反丁烯二酸二王丙酯等,均表现出很低的聚合反应活性,因而得不到高分子量的均聚物;而某些非正烷基酯的DRFs单体,如反丁烯二酸二异丙酯则显示出很高的聚合反应活性并可形成高分子量的聚合物。对反丁烯二酸酯同其他乙烯类单体(如苯乙烯等)的共聚研究曾有一些报道,但对DRFs单体之间的共聚     

几种反丁烯二酸酯的自由基聚合反应研究

以 AIBN及BPO为引发剂,对几种自制的反丁烯二酸酯(DRFs)单体,如反丁烯二酸二环已酯(DCHCF)、反丁烯二酸二仲丁酯(DsBF)、反丁烯二酸二仲戊酯(DsAF)、反丁烯二酸甲基异丙基酯(MiPF)等单体的自由基聚合反应进行了研究。研究了它们的自由基聚合反应动力学,并求得它们的聚合反应表现活化能值在80.0～95KJ/mol之间。采用IR,~1H-NMR,~(13)C-NMR等手段对所得到的聚合物结构进行了表征。还对聚合物的溶解性及热性能进行了研究。     

反丁烯二酸酯类的自由基聚合反应研究

以AIBN或BPO为引发剂,采用自由基聚合方法研究了十几种反丁烯二酸酯类(DRFs)的聚合反应。结果表明,随着DRFs单体中酯基结构的不同,单体的聚合反应活性差别很大,其大小顺序为DCHF>DtBF>DiPF>MiPF,DEF,DsBF,DsAF>DEHF>DnHF>DiBF,DiAF,DnPF,DnBF,DnAF。结合实验结果及聚合物的结构分析,从单体的结构和链自由基的结构出发,对上述现象进行了初步的解释。采用IR,~1H-NMR等表征手段,对得到的DRFs聚合物进行了结构表征,研究了DRFs聚合物的表观形态及其成膜性能。     

聚DL-乳酸的合成及其热性能研究

以辛酸亚锡为催化剂催化丙交酯开环聚合DL-乳酸(PDLLA)。研究了影响PDLLA分子量的因素包括丙交酯单体的纯度、催化剂的浓度、反应温度、反应时间及真空度等。用DSC,TGA分析了不同分子量PDLLA的警警化转变和热失重。结果表明,PDLLA是热不稳定聚合物,残留的单体、催化剂及低聚物是影响PDLLA热稳定性的因素,除去其中残留的单体、催化剂及低聚物可以提高PDLLA的热稳定性。     

Lewis酸碱对在聚合中的应用

自从Stephan和Erker两位科学家提出“位阻型(Frustrated)Lewis酸碱对”概念以来,Lewis酸碱对的催化化学得到极大的关注。近年来,人们也发现Lewis酸碱对在催化极性乙烯基单体和内酯单体聚合中有着重要的应用。Lewis酸碱对催化极性乙烯基单体聚合可形成具有高分子量和窄分子量分布的聚合物,而催化活性与所使用的Lewis酸碱对关系密切,最有效的Lewis酸是Al(C₆F₅)₃和B(C₆F₅)₃,Lewis碱是有机磷、氮杂环卡宾和氮杂环卡宾烯和膦腈超强碱,可聚合的单体包括甲基丙烯酸甲酯、γ-甲基-α-亚甲基-γ-丁内酯、α-亚甲基-γ-丁内酯、 丙烯酸正丁酯、 N,N-二甲基丙烯酰胺、 N,N-二苯基丙烯酰胺、 乙烯基磷酸二乙酯、2-乙烯基吡啶、2-异丙烯基-2-氧 NFDA1 唑林以及非对称的极性二乙烯基单体。聚合过程包括:链引发、链增长和链终止。链引发过程是通过Lewis酸、Lewis碱和单体相互作用形成两性离子,链增长是通过双金属活化单体加成方式进行,链终止通过两种途径:1)增长聚合物链中活化的酯氧负离子对相邻酯中羰基碳原子的亲核进攻形成δ-戊内酯;2)增长聚合物链中活化的烯酯碳负离子对倒数第三个酯中羰基碳原子的亲核进攻形成β-酮酸酯。Lewis酸碱对催化内酯单体聚合可形成线形和环状聚合物,所使用的Lewis酸为Zn(C₆F₅)₃、有机铝、氯化铟,Lewis碱为有机胺。     

甲基丙烯酸N,N-二甲氨基乙酯/丙烯酸N,N-二甲氨基乙酯的可逆加成断裂链转移聚合研究

合成了二硫代苯甲酸2- (乙氧基羰基)异丙酯(ECPDB)、二硫代苯甲酸异丙苯酯(CDB)、二硫代苯甲酸1 苯基乙酯(PEDB) 3种二硫代苯甲酸酯链转移剂.以这3种转移剂为基础,用凝胶渗透色谱和核磁共振测试了甲基丙烯酸N ,N 二甲氨基乙酯(DMAEMA)和丙烯酸N ,N 二甲氨基乙酯(DMAEA)两种碱性单体的可逆加成断裂链转移(RAFT)聚合的聚合物分子量、分子量分布和结构.发现有的聚合体系聚合物分子量分布较窄,但实验数均分子量与理论数均分子量相差较大;有的体系则转化率很低,聚合物分子量很小.这些可能是由聚合体系中单体活性和链转移剂链转移能力之间的匹配不太协调,使可逆加成断裂链转移快速平衡反应发生偏移或破坏造成的.因此,可通过更换单体或链转移剂来调节这种匹配,从而使可逆加成断裂链转移快速平衡保持稳定,达到聚合更可控,实验分子量与理论分子量更接近,分子量分布更窄的目的.     

非手性席夫碱-异丙氧基铝引发外消旋丙交酯的立构选择性聚合

摘要以非手性的席夫碱-异丙氧基铝(Ⅱ)引发外消旋丙交酯(rac-LA)的立构选择性聚合. 其聚合动力学研究结果表明, 聚合反应对于单体符合一级反应动力学. 所得聚合物的数均分子量与单体转化率成正比, 并且分子量分布很窄, 表明该聚合反应具有良好的可控性. 此外所得的聚外消旋乳酸是tm为179 ℃的结晶性聚合物. 13C NMR和同核去偶1H NMR谱表明, 所得的聚乳酸是一种立构嵌段聚合物, 平均嵌段长度为11个乳酸单元.     

反丁烯二酸酯类共聚物的透气性能

反丁烯二酸酯类聚合物的气体分离性能研究已有许多报道。聚反丁烯二酸二叔丁酯(Po_2=130barrer,ao_2/N_2=3.7)和聚反丁烯二酸二异丙酯(Po_2=51barrer,ao_2/N_2=2.9)等都具有较好的氧氮分离性能。但是,由于这类聚合物的脆性很大,使其应用受到较大的限制。本文报道不同系列的反丁烯二酸酯类共聚物的合成和它们的氧氮透过性能。 实验部分     

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.     

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.     

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.