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合成了两种新的C60侧链线性聚硅氧烷,并用作毛细管气相色谱固定相.该类固定相柱效高,使用温度范围宽,热稳定性好,最高柱温达360℃,基线漂移量为3×10-14~4×10-14nm,对各类位置异构体有独特的分离效果,尤其对高沸点化合物如糖、多环芳烃和邻苯二甲酸酯类有良好的分离选择性. 相似文献
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在含氟聚芳醚侧链引入磺化萘酚基团,制备了一类侧链磺化型含氟聚芳醚(s SPFAE),采用溶液浇铸法制膜并对膜进行了表征和分析.制备的膜材料离子交换容量达到1.42~2.03 mmol/g,均透明柔韧,杨氏模量高于1.0 GPa,拉伸应变达到66%~105%.吸水性及膨胀性测试结果表明该系列膜具有较低的吸水率和良好的尺寸稳定性,在测试温度范围内(30~90℃)吸水率为21%~51%,尺寸变化率低于7%.s SPFAE膜具有良好的热稳定性及氧化稳定性,TGA测试中320~360℃时的重量损失低于5%,在Fenton溶液中80℃处理1 h后的失重率小于2%.同时,该系列膜表现出较高的电导率水平,如SPFAE-0.8膜(IEC=2.03 mmol/g)在80℃时电导率达到217 m S/cm. 相似文献
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NP-HPLC分离氨氯地平对映体及其含量测定 总被引:1,自引:0,他引:1
建立直接拆分氨氯地平对映体的HPLC方法,并用于其含量测定.以CHIRALPAK AD-H为固定相,在正相条件下考察了流动相组成、流速、柱温等因素对氨氯地平对映体分离度的影响.在优化条件下,分别测定了氨氯地平对映体的含量.实验表明,以正己烷-乙醇-二乙胺(95 : 5 : 0.1,体积比)为流动相,流速 1.0 Ml/min,检测波长 360 nm,柱温 30 ℃,氨氯地平对映体的质量浓度均在0.01 ~0.06 g/L范围内线性关系良好(Rr=0.998 3,Rs=0.998 7).高、中、低3个浓度平均回收率(n=3)分别为99%、101%、101%,相对标准偏差依次为0.76%、0.68%、0.98%.该分析方法准确可靠、快速、简单、重复性好,可用于左旋氨氯地平工业化制备中动态拆分过程的跟踪分析及产品质量控制. 含量.实验表明,以正己烷-乙醇-二乙胺(95 : 5 : 0.1,体积比)为流动相,流速 1.0 Ml/min,检测波长 360 nm,柱温 30 ℃,氨氯地平对映体的质量浓度均在0.01 ~0.06 g/L范围内线性关系良好(r_R=0.998 3,r_S=0.998 7).高、中、低3个浓度平均 收率(n=3)分别为99%、101%、101%,相对标准偏差依次为0.76%、0.68%、0.98%.该分析方法准确可靠、快速、简单、重复性好, 相似文献
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为了研究合成温度对聚铝碳硅烷(PACS)结构的影响, 采用具有Si—C骨架结构的低分子量液态聚碳硅烷(LPCS)与乙酰丙酮铝[Al(AcAc)3]为原料, 在300, 360和420 ℃下分别合成了固态PACS, 并对合成的PACS样品进行元素组成及结构表征. 表征结果显示, 合成温度明显影响样品的Al, O含量及Si—H键数量. 合成温度升高, Al含量与O含量增大, 但PACS中的Si—H键数量急剧减少, 在360 ℃下合成的样品具有理论Al含量, 而在300和420 ℃下合成的样品的Al含量分别小于和大于理论Al含量. 27Al MAS NMR结果显示, Al与O形成AlO4, AlO5和AlO6 三种配位形式. 反应过程中消耗Si—H键形成Si—O—Al交联结构是PACS数均分子量及多分散系数增加的主要原因. 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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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. 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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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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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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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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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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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. 相似文献
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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. 相似文献
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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. 相似文献