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1.
L 苏糖酸作为金属离子的载体,可使金属离子易于与氨基酸或蛋白质结合而被动物吸收和利用[1-3],钒在1971年被确定为生物体必需的微量元素[4],具有多种生理作用和药理活性,与糖尿病的关系十分密切。近年来国内外用于抗糖尿病生物学研究的钒化合物绝大多数为简单的盐类化合物,脂溶性小,难以吸收,同时对胃肠道刺激性大[5]。本文以L 苏糖酸钙与草酸氧钒(VOC2O4)反应后的溶液加无水乙醇制得[VO(C4H6O5)]2·3H2O,并进行等离子发射光谱(ICP)、元素分析、IR光谱、TG DTG表征。1 实验部分1.1 试剂与仪器L 抗坏血酸(Vc),H2C2O4·2H2O… 相似文献
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以L-苏糖酸钙与草酸的复分解反应得到的L-苏糖酸溶液,在80℃下与过量 CoO反应较长时间,滤液浓缩后加无水乙醇制得L-苏糖酸钴粉红色粉末。用化学分 析及元素分析确定其组成为Co(C4H7O5)·H2O,IR光谱分析结果表明新化合物中苏糖 酸以羧基氧原子与Co^+配位。TD-DTG结果说明,它在热分解中有一定稳定性,经 脱水生成Co-(C4H7O5)2,最后生成CoO。用转动弹热量计测得其恒容燃烧能ΔcE为( -3504.47±1.64)kJ·mol^-1,计算得其标准燃烧焓和标准生成焓ΔfHm^θ分别为 (-3501.99±1.64)和(-2170.67±1.97)kJ·mol^-1。 相似文献
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L-苏糖酸作为金属离子的载体 ,可使金属离子易与氨基酸或蛋白质结合而被动物吸收和利用 [1] 。镍是人体必需微量元素之一 ,它参与金属特异酶的各种功能 ,形成活性中心 ,通过形成络合物参与底物与酶的结合 ,通过抑制或促进其它金属元素的作用控制酶活性。目前已知镍有促进红细胞的再生 ,刺激生血机能作用 ,它还可能是胰岛素分子中的辅酶成分 ,与增强胰岛素效应、降低血糖水平有关 [2 ]。因此 ,研究镍 ( )与 L -苏糖酸的化合作用很有必要。文献 [3,4]报道了 Fe2 +、Zn2 +、K+、Na+、Mg2 +和 Cr3+与L-苏糖酸所形成的化合物的制备方法。而… 相似文献
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以L-苏糖酸钙与草酸的复分解反应得到的L-苏糖酸溶液,在80 ℃下与过量MgO反应较长时间, 滤液浓缩后加无水乙醇制得L-苏糖酸镁白色粉末.用化学分析及元素分析确定其组成为Mg(C4H7O5)2•H2O. IR光谱分析表明,化合物中苏糖酸以羧基氧原子与Mg2+配位,Mg2+为sp3杂化态,配位数为4. TD-DTG结果说明,它在热分解中有一定稳定性,而经脱水和生成Mg(OAc)2,最后生成MgO.用转动弹热量计测得其恒容燃烧能ΔE为 (-10407.34±4.67) kJ•mol-1,计算其标准燃烧焓ΔcHm和标准生成焓ΔfHm分别为(-3 249.49±1.46) kJ•mol-1和(-2 786.23±1.84) kJ•mol-1. 相似文献
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含铜类水滑石催化材料热分解过程的研究 总被引:2,自引:0,他引:2
共沉淀法合成了Cu0.13Mg0 6Al0.27(OH)2(CO3)0.135·xH2O类水滑石物质 (CuHTlc) ,采用XRD、DTA TG、BET、TEM和27AlMASNMR技术对其热分解过程进行了表征。结果表明 ,在较低焙烧温度时 (低于300℃ ),氢氧根和层间水部分脱除 ,但水滑石仍保持其层状结构 ;500℃时 ,其层状结构被完全破坏 ,出现氧化镁晶相结构 ,随着焙烧温度的进一步升高 ,尖晶石晶相生成。500℃时的焙烧产物具有最大比表面 (193m2·g-1)。当温度高于500℃ ,焙烧产物组成可表示为Cu0.13Mg0.6Al0.27O0.135,CuHTlc的热分解过程可表示为 :Cu0.13Mg0.6Al0.27(OH)2(CO3)0.135·xH2O→Cu0.13Mg0.6Al0.27O0.135 (1 x)H2O 0.135CO2。 相似文献
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L-苏糖酸与金属离子的配位性能 总被引:9,自引:0,他引:9
本文在298K、I=0.1 mol·L-1 KNO3条件下测定了L-苏糖酸的质子化常数及其与钙(Ⅱ)、镉(Ⅱ)、锌(Ⅱ)、钴(Ⅱ)、铜(Ⅱ)二元配合物的生成常数。L-苏糖酸的质子化常数与葡萄糖酸的质子化常数一致,pKa为3.56。其与金属离子的配位方式也与葡萄糖酸一致,但其二元配合物的生成常数明显比葡萄糖酸大。L-苏糖酸与不同金属离子作用的方式不同,与钙(Ⅱ)、镉(Ⅱ)、锌(Ⅱ)、钴(Ⅱ)配位时不解离出醇羟基质子,而与铜(Ⅱ)配位时则 相似文献
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Cu-Ni-Mg-Al-CO_3四元水滑石的合成及结构分析 总被引:4,自引:0,他引:4
以Cu(NO3)2 ·3H2 O,Ni(NO3)2 ·6H2 O,Mg(NO3)2 ·6H2 O和Al(NO3)3·9H2 O为原料,以NaOH和Na2 CO3为沉淀剂,采用成核/晶化隔离法合成了Cu Ni Mg Al CO3四元水滑石,通过XRD,FT IR,TG DTA,ICP等手段对样品进行测试和表征,并且对水滑石结构的层板和层间阴离子相互作用进行分析和讨论.结果表明,控制Cu2 +离子与其它二价金属离子的配比,可制备晶体结构规整的M(II)4 M(III)2 (OH)12 CO3·4H2 O型水滑石;Cu2 +离子的引入导致了明显的Jahn Teller效应;且随Mg2 +量的增加,使得这种效应更加显著,另一方面Mg2 +量的增加有利于Cu Ni Mg Al CO3四元水滑石晶体在a方向上生长,增强其热稳定性 相似文献
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L-苏糖酸作为金属离子的载体 ,可使金属离子易于与氨基酸或蛋白质结合而被动物吸收和利用[1] ,L -苏糖酸钙就是一种优秀的钙补充剂 ,其吸收率达 95%以上 ,是传统钙补充剂的 2~ 3倍 ,无任何毒副作用 ,1 %的 L -苏糖酸钙能使维生素 C的吸收增加 1 .8倍[2 ,3 ] .国外已有苏糖酸产品及专利[4 ] ,国内也有苏糖酸钙产品问世 .文献 [5]报道 0 .1 mol/ L苏糖酸钙在生理 p H下 ,将有 87%钙为分子状态 ,这一结果显然支持了“分子补钙”的理论 ,也是其成为优秀钙补充剂的原因 .锌是人体中必需的 1 4种微量元素之一 ,与人体中不下2 0 0种金属酶有关 … 相似文献
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Copper oxides were prepared by direct heating and decomposing copper(Ⅱ) salts, such as Cu 2(OH) 2CO 3, Cu(NO 3) 2·3H 2O, Cu 2C 6H 4O 7·2 5H 2O, CuC 2O 4·2H 2O and CuAc 2·H 2O. The phase, surface area and catalytic activity of the oxides for H 2O 2 decomposition were investigated by means of XRD and BET measurements. It has been demonstrated that the characteristics of copper oxides obtained from different precursors are much different from each other. Monocomponent nano CuO, which has higher catalytic activity for H 2O 2 decomposition, can be prepared by direct heating and decomposing Cu 2(OH) 2CO 3. On the other hand, CuO in the decomposition products of the organic acid copper can be partially reduced to Cu 2O and Cu in the reducing atmosphere, and the Cu 2O component in the products has higher catalytic activity for H 2O 2 decomposition. 相似文献
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Three novel complexes [Cu(L1)2(H2O)2] (1), [Ni(L1)2(H2O)2]·(H2O)4(2,HL1=5-methyl-1-(4-methylphenyl)-1,2,3-triazole-4-carboxylic acid) and [Ni2 (HL2)2(CH3OH)6]·(CH3OH)2(3,H3L2=1,2,3-triazole-4,5-dicarboxylic acid) were synthesized and characterized by elemental analysis, IR and X-ray diffraction. Complexes 1 and 2 are mononuclear structures, and are assembled into a two-dimensional sheet by C(7) H(7)···O(3) weak interactions or hydrogen-bonding interaction. Complex 3 is a centrosymmetric dinuclear structure, and is assembled into a three-dimensional supramolecular structure by hydrogen-bonding interaction. 相似文献
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The spectral-polarization characteristics of absorption and phosphorescence of molecules of the initial form of nitro-substituted
indolinospirobenzothiopyran were studied in oriented polyethylene films and in solutions with different polarity. An oscillator
model of the electron transitions responsible for the formation of absorption and luminescence spectra was suggested. It was
established that the principal differences in the spectral and photophysical properties of the compound studied and its oxygen-containing
analog are associated with the fact that the electronegativity of the S atom is lower than that of the O atom.
Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1143–1146, June, 1997. 相似文献
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Two vanilloids, (5E)-8-(4-hydroxy-3-methoxyphenyl)oct-5-en-4-one (1) and 4-[3-hydroxydecyl]-2-methoxyphenol (2), isolated from the dried seeds of Grains of Paradise (Aframomum melegueta), were synthesized; the latter compound was made as the S-enantiomer and the material derived from the seeds was found to be a 1:1.7 mixture of the R and S isomers. The synthetic route used should allow the preparation of analogs having extended alkyl chains and consequently different lipophilicity, and 3, a homolog of 2, was also prepared. 相似文献
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Cotton cellulose was swollen in a sodium hydroxide solution and carboxymethylated by a two-bath method for different periods of time for each process. The kinetics of acid hydrolysis and the crystallinity of the swollen and carboxymethylated samples were measured. The proportion of broken bonds, rate constants for hydrolysis, and permeability of cellulose to hydrolyzing agents were calculated. The susceptibility of glycosidic linkages to acid hydrolysis was improved by carboxymethylation more than by swelling in alkali. The increased accessibility of carboxymethylcellulose to acid was regarded as a consequence of increased intra-and intercrystalline swelling and of the glycosidic bonds' weakness caused by the electron-attracting carboxymethyl group on the C-6 position. 相似文献
15.
Stepkowska E. T. Perez-Rodriguez J. L. Jimenez de Haro M. C. Sayagues M. J. 《Journal of Thermal Analysis and Calorimetry》2002,69(1):187-204
Main hydration products of two cement pastes, i.e. CSH-gel, portlandite (P) (and specific surface S) were studied by static heating, and by SEM, TEM and XRD, as a function of cement strength (C-33 and C-43) hydration time (th) and subsequent hydration in water vapour.Total change in mass on hydration and air drying, Mo, increased with strength of cement paste and with hydration time. Content of water escaping at 110 to 220°C, defined as water bound with low energy, mainly interlayer and hydrate water, was independent on cement strength but its content increased with (th). Content of chemically bound (zeolitic) water in CSH-gel, escaping at 220-400°C, was slightly dependent on strength and increased with (th). It was possibly derived from the dehydroxylation of CSH-gel and AFm phase. Portlandite water, escaping at 400-500°C, was independent on cement strength and was higher on longer hydration. Large P crystals were formed in the weaker cement paste C-33. Smaller crystals were formed in C-43 but they increased with (th). Carbonate formated on contact with air (calcite, vaterite and aragonite), decomposed in cement at 600-700oC. It was high in pastes C-33(1 month) and C-43(1 month), i.e. 5.7 and 3.3%, respectively; it was less than 1% after 6 hydration months (low sensitivity to carbonation) in agreement with the XRD study showing carbonates in the air dry paste (1month), and its absence on prolonged hydration (6 months) and on acetone treatment. Water vapour treatment of (6 months) pastes or wetting-drying increased this sensitivity.Nanosized P-crystals, detected by TEM, could contribute to the cement strength; carbonate was observed on the rims of gel clusters.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
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The aim of the presented work was the investigation of thermal oxidation of ilmenite in static air atmosphere. The investigations
were carried out by use of a derivatograph (MOM, Hungary). The changes of crystallographic structure of investigated samples
were identified by X-ray diffractometry on Philips PW-1710 diffractometer. In temperature above 500°C appears structure of
hematite Fe2O3. On the basis of the thermogravimetric measurements, the contracting area and contracting volume models were found as the
best fitting experimental data.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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Cyclopropyl derivative of 2,6-di-tert-butylphenol is synthesized as a probe to investigate the mechanism of base-catalyzed autooxidation of phenol derivatives. Our study indicates that one electron reduction of molecular oxygen from phenolate gives phenoxyl radical 3, a key intermediate of autooxidation. The coupling of phenoxyl radical and superoxide radical gives peroxylate anion 4 and produces the final epoxy alcohol adduct 6. 相似文献
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