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991.
一种氧化海藻酸钠基温敏凝胶的制备与性能 总被引:1,自引:0,他引:1
合成出一种具有温敏特性的多官能团的大分子聚(N-异丙基丙烯酰胺-丙烯酸甲酯-丙烯酰肼)(PNMH),用它交联氧化的海藻酸钠(OSA),得到可生物降解的温敏凝胶PNMH-OSA.分别以凝胶的透光率随温度变化和凝胶在磷酸盐缓冲液(PBS)中的溶胀比随时间变化来考察凝胶的温敏性能和降解性能,并采用傅立叶变换红外光谱(FTIR)和激光共焦拉曼光谱(LCRS)对样品进行了表征.结果表明,PNMH-OSA凝胶是通过PNMH上的—NHNH2和OSA上的—CHO反应生成C N键而形成的化学交联凝胶;随着凝胶中PNMH量的增加,PNMH-OSA凝胶的温敏性增强,降解时间延长;温敏组分的含量对PNMH-OSA凝胶的溶胀和降解性能与温度的关系影响显著. 相似文献
992.
《Journal of Coordination Chemistry》2012,65(16):1405-1412
The crystal structures of sodium 4-amino-2-hydroxybenzoate dihydrate [NaL·2H2O, L?= C6H3(NH2)(OH)COO] and potassium 2-aminobenzoate monohydrate [KL*·H2O, L*?=?C6H4(NH2)COO] were determined by X-ray diffraction methods. The compound NaL·2H2O crystallizes in the monoclinic system, space group P21/c with a?=?8.820(2), b?=?14.632(3), c?=?6.948(2)?Å, β?=?97.88(3)°. The structure consists of sodium ion pairs joined together by tridentate 4-amino-2-hydroxybenzoate moieties creating a polymeric chain. In the metal centres, two water molecules bridge the sodium atoms. Five oxygen atoms and one nitrogen atom form a distorted octahedral environment. The compound KL*·H2O crystallizes in the monoclinic system, space group P21/c with a?=?14.684(3), b?=?7.618(2), c?=?7.512(2)?Å, β?=?96.95(3)°. The structure consists of octacoordinated potassium atoms bonded with three water molecules and five carboxylate oxygen atoms. Water molecules appear as bridging ligands. The 2-aminobenzoate ligand acts as a pentadentate ligand with the molecular network stabilized by hydrogen bonds. Among the polymeric chains in both structures appear noncovalent interactions of type N?H···X. 相似文献
993.
《Journal of Coordination Chemistry》2012,65(8):843-850
The crystal structure, infrared spectrum and thermal stability of 3-(4-hydroxy-3-methoxyphenyl)-2-propenoic acid sodium salt have been studied. The compound of general formula {[Na2L2?·?3H2O]?·?H2O} n is a two-dimensional polymer, in which Na ions are bridged by one or two water molecules and additionally coordinated to oxygen atoms of carboxylate, hydroxy and methoxy groups. The structure is stabilized by a hydrogen bond network. The compound dehydrates at 75°C and then decomposes at 150°C. The IR spectra of the salt and free acid are discussed. 相似文献
994.
《Journal of Coordination Chemistry》2012,65(7):1005-1018
Solid compounds of Cd(II), Hg(II) and Pb(II) with the sodium salt of morin-5′-sulfonic acid (NaMSA) were obtained. The molecular formula of the complexes are: Cd(C15H8O10SNa)2?·?6H2O, CdOH(C15H8O10SNa)?·?4H2O, Hg(C15H8O10S)?·?4H2O and Pb(C15H8O10S)?·?3H2O. Some of their physicochemical properties such as UV-Vis, infrared, 13C NMR and mass spectra, thermogravimetric analysis, and solubility were studied. On the basis of spectroscopic data NaMSA was bound to Cd2+ via 4C=O and 3C?–?oxygen and the Hg2+ and Pb2+ ions by 5C–OH, 4C=O and 3C–OH. 相似文献
995.
Uniform sodium jarosite particles were obtained by forced hydrolysis of ferric salt solutions to which copper sulfate, sodium
sulfate, and sodium nitrate were added. It was found that at the same concentrations of ferric and sulfate ions the particle
size and yield decreased with the lowering of the concentration of sodium ions, but the morphology remained the same. At a
sufficiently small content of sodium in the reacting solution, no precipitation of sodium jarosite particles was observed.
Finally, chemical and XRD analyses showed that small amounts of copper ions are incorporated in the crystal lattice which,
with the change in the Na+/H3O+ ratio, slightly affected the structure of this mineral, but not its other properties.
Received: 12 July 2000 Accepted: 18 August 2000 相似文献
996.
The effect of aqueous binary mixtures of isomeric butanediols on the micellization of sodium dodecyl sulfate has been investigated.
Conductivity and fluorescence techniques were employed to determine the critical micellar concentration, the degree of dissociation
of the counterions and the aggregation numbers of the surfactants in these binary blends. Differential conductivity plots
were employed to distinguish between the cooperative and the stepwise aggregation process of the surfactant in each solvent
system. The mass-action model was employed to calculate the hydrophobic and the electrostatic contributions to the Gibbs energy
of micellization as well as the monomer and the counterion concentrations in the postmicellar region. The thermodynamic parameters
calculated for each system indicate that the micellization process occurs more readily in the presence of cosolvent owing
to the formation of mixed micelles.
Received: 5 July 2000 Accepted: 25 July 2000 相似文献
997.
对小麦粉中甲醛提取方法、甲醛与2,4-二硝基苯肼的衍生化反应条件以及甲醛衍生物的提取净化方法进行了研究, 建立了一种小麦粉中甲醛(吊白块)的高压液相色谱测定方法.该方法在甲醛浓度为0.026~0.832 μg/mL范围内与其衍生物的色谱峰面积呈显著线性相关, 相关系数r=0.9986. 小麦粉中甲醛不同添加量的平均回收率>99%;吊白块不同添加量的平均回收率>94%(以甲醛量计). 重复测定相对标准偏差平均为4.5%, 甲醛的检出限为9.6 μg/L, 相当于小麦粉中甲醛的最小检出量为0.24 mg/kg. 相似文献
998.
研究了钠、钾助剂对FeMn 合成低碳烯烃催化剂结构及性能的影响. 低温N2吸附、X射线光电子能谱(XPS)、X射线衍射(XRD)、H2程序升温还原(H2-TPR)、CO/CO2程序升温脱附(CO/CO2-TPD)、Mössbauer 谱和CO+H2反应的研究结果表明,增加Mn助剂含量促进了活性相的分散和低碳烯烃的生成,而过多锰助剂在催化剂表面的富集则降低了费托合成反应的CO转化率;钾助剂和钠助剂的加入均抑制了催化剂的还原并且促进了CO2和CO的吸附. 比较还原后(H2/CO摩尔比为20)和反应后(H2/CO摩尔比为3.5)催化剂的体相结构可以发现,在FeMn、FeMnNa和FeMnK催化剂中,由于钾助剂的碱性和CO吸附能力较强,因此体相中FeCx的含量相对较高;而活性测试结果表明,FeMnNa催化剂拥有最好的CO转化率(96.2%)和低碳烯烃选择性(30.5%,摩尔分数). 相似文献
999.
提出了离子色谱法同时测定卷烟纸中钠、钾、镁和钙含量的方法。卷烟纸试样经硝酸-过氧化氢-氢氟酸微波消解,以IonPac CS16阳离子交换柱为固定相,用0.027 mol.L-1甲烷磺酸溶液作流动相。钠、钾、镁和钙4种元素在30 min内可完全分离;各离子的检出限(3S/N)分别为13,15,8.1,97 mg.L-1。方法的加标回收率在100.9%~108.8%之间,测定值的相对标准偏差(n=5)在0.87%~3.4%之间。 相似文献
1000.
Mononuclear neutral arene ruthenium(II) β-diketonato complexes of the general formula (η6-arene)Ru(LL)Cl [LL = 1-phenyl-3-methyl-4-benzoyl pyrazol-5-one (L1), arene = C6H6 (1), p-iPrC6H4Me (2), C6Me6 (3); arene = p-iPrC6H4Me, LL = 1-benzoylacetone (L3) (8); arene = p-iPrC6H4Me, LL = dibenzoylmethane (L4) (9)] have been synthesized and their subsequent substitution reactions with NaN3 in alcohol at room temperature yielded the corresponding neutral terminal azido complexes (η6-arene)Ru(LL)N3 [LL = 1-phenyl-3-methyl-4-benzoyl pyrazol-5-one (L1), arene = C6H6 (4), p-iPrC6H4Me (6), C6Me6 (7); arene = p-iPrC6H4Me, LL = dibenzoylmethane (L4) (10)] as well as a cationic complex [(η6-p-iPrC6H4Me)Ru(L4) (PPh3)]BF4 (12) with PPh3. The [3 + 2] cycloaddition reaction of selective azido complexes with the activated alkynes dimethyl and diethyl acetylenedicarboxylates produced the arene triazolato complexes [(η6-arene)Ru(LL){N3C2(CO2R)2}] [arene = p-iPrC6H4Me, LL = L1, R = Me (13); arene = C6Me6, LL = L1, R = Me (14); arene = C6Me6, LL = acetyl acetone (L2), R = Me (15); arene = C6Me6, LL = L3, R = Me (16); arene = p-iPrC6H4Me, LL = L1, R = Et (17); arene = C6Me6, LL = L1, R = Et (18); arene = C6Me6, LL = L2, R = Et (19); arene = C6Me6, LL = L3, R = Et (20)]. With fumaronitrile the reaction yielded the triazoles [(η6-arene)Ru(LL)(N3C2HCN)] [arene = p-iPrC6H4Me, LL = L1 (21), arene = C6Me6, LL = L1 (22), arene = C6Me6, LL = L2 (23), arene = C6Me6, LL = L3 (24)]. In the above triazolato complexes only N(2) isomer was obtained. The complexes were characterized on the basis of spectroscopic data. Crystal structure of representatives complexes were determined by single crystal X-ray diffraction. 相似文献