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目前聚羧酸减水剂大多由甲基丙烯酸合成,而马来酸酐因其结构对称、活性较低等特点而合成工艺简单、易于控制。本文研究以马来酸酐、甲氧基聚乙二醇、乙烯基磺酸钠、甲基丙烯酸为原料采用先酯化再共聚的方法合成出了含有羧酸基、磺酸基、聚氧乙烯基的马来酸酐类聚羧酸减水剂。酯化反应是极其关键的一步,通过研究表明马来酸酐甲氧基聚乙二醇单酯最佳合成条件为:酸醇比为1.15:1、催化剂用量为MPEG质量的6%,、反应时间4h,反应温度为110℃;马来酸酐聚羧酸减水剂的最佳合成配比为n(MPEG-MA):n(SVS):n(MAA)=1:0.75:5。马来酸酐聚羧酸减水剂最佳掺量为0.5%,与市场上的减水剂最佳掺量时的效果相当。 相似文献
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研究了马来酸酐-丙烯酸共聚物(MA-Co-AA)的微波辐射合成及其助洗性能,并与常规方法制得产品的助洗性能进行了比较.结果表明,微波辐射法合成MA-Co-AA的较佳工艺条件是:马来酸酐(MA)与丙烯酸(AA)的摩尔比为n(IA)∶n(AA)=1∶3.5,引发剂用量为单体总质量的7%,微波功率为600W,辐射时间为8mi... 相似文献
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《化学研究与应用》2017,(4)
对不同分子量的烯丙基聚乙二醇醚(APEG)进行封端改性,制得相应的磺酸基改性的APEG单体(APEGS),并与分子量为2400的甲基烯丙基聚氧乙烯醚TPEG和丙烯酸(AA)、马来酸酐(MA)、乙酸乙烯酯(EVAc)在氧化还原引发体系和链转移剂的作用下,进行水溶液自由基共聚,合成了一种磺酸基改性的聚羧酸减水剂SPCE,并对其性能进行了检测。试验结果表明:磺酸基改性的APEG-700为最佳共聚单体,且共聚体系中n(TPEG)∶n(APEGS)∶n(AA)∶n(MA)∶n(EVAc)的最佳配比为1.0∶0.25∶3.0∶2.0∶1.0,合成的聚羧酸减水剂不仅具有良好的分散性和保坍性,而且与不同水泥和矿物掺合料混凝土的适应性好。 相似文献
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将引发剂偶氮二异丁腈(AIBN)、共聚单体苯乙烯(St)和马来酸酐(MA)溶解于甲苯中,采用沉淀聚合法合成苯乙烯-马来酸酐共聚物(SMA).分别研究了反应温度、引发剂用量、反应时间、单体配比和单体浓度对聚合物得率和酸酐含量的影响.采用正交实验确定最优反应条件为:单体浓度20%,单体物质的量比为1∶1,引发剂用量为0.60%,反应温度为86℃,反应时间2h,产物得率为86.86%,酸酐含量为50.28%.并利用傅里叶变换红外光谱(FTIR)、核磁共振碳谱(~(13)C NMR)、凝胶渗透色谱(GPC)和热分析法分别研究聚合物的分子结构、相对分子质量及相对分子质量分布和热稳定性.结果表明产物是苯乙烯-马来酸酐交替共聚物,相对分子质量分布较窄,具有良好的热稳定性. 相似文献
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以靛红酸酐、醋酸铵和芳香腈为原料,在碘化亚铜的催化下合成得到一系列2-芳基取代喹唑啉-4(3H)-酮(1a~1j),产物结构经~1H NMR和ESI-MS表征。并以靛红酸酐和苯腈的反应为模型反应,考察影响产物1a收率的因素,确定最佳反应条件为:醋酸铵为反应溶剂;物料比为n(苯甲腈)∶n(靛红酸酐)=1.1∶1;碘化亚铜的量为n(CuI)∶n(靛红酸酐)=0.10∶1,在120℃反应4 h。在最佳反应条件下,化合物1a收率87%。采用MTT法测定所合成的化合物1a~1j对人肝癌细胞HepG2及人非小细胞肺癌A549的体外抗肿瘤活性。结果表明,化合物1h对A549细胞的体外生长具有较明显的抑制作用,IC_(50)为10.2μmol·L~(-1),可以作为抗肿瘤药物研究的先导化合物。 相似文献
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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%. 相似文献
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Toward new camptothecins. Part 6: Synthesis of crucial ketones and their use in Friedländer reaction
Laurent Gavara Thomas Boisse Jean-Pierre Hénichart Adam Daïch Philippe Gautret 《Tetrahedron》2010,66(38):7544-5571
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. 相似文献
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Uroš Grošelj Mojca Žorž Amalija Golobič Branko Stanovnik Jurij Svete 《Tetrahedron》2013,69(52):11092-11108
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. 相似文献
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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. 相似文献
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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. 相似文献
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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. 相似文献
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Rebecca J. Burton Mandy L. CrowtherNeal J. Fazakerley Shaun M. FilleryBarry M. Hayter Jason G. KettleCaroline A. McMillan Paula PerkinsPeter Robins Peter M. SmithEmma J. Williams Gail L. Wrigley 《Tetrahedron letters》2013
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. 相似文献
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N. A. Nedolya 《Chemistry of Heterocyclic Compounds》2008,44(10):1165-1219
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. 相似文献
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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%). 相似文献
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Shashikant U. Dighe Surya K. Samanta Shivalinga Kolle Sanjay Batra 《Tetrahedron》2017,73(17):2455-2467
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. 相似文献