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生物体液可看作是由多种离子与氨基酸、蛋白质组成的混合电解质溶液,研究电解质或离子与这些氨基酸、蛋白质间的相互作用对了解生物体液内复杂的作用机理,揭示许多生命现象具有重要意义。1978年以来,Kelley采用有液体接界的电池研究了几种氨基酸或肽与一些碱金属氯化物的相互作用自由能,为研究电解质与氨基酸、蛋白质间的相互作用奠定了基础。研究溶质的迁移热力学性质是了解溶质-溶剂间相互作用以及溶液微观结构的常用手段。以氨基酸水溶液作为含水离子溶剂,用电动势法研究电解质从水到该溶液中的迁移热力学性质,进而研究电解质与氨基酸间的相互作用是可行的,目前这方面的研究工作很少见文献报导。本文通过测定电池: 相似文献
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NaIO4-H2O2-盐酸异丙肾上腺素-Cu2+体系化学发光测定盐酸异丙肾上腺素 总被引:1,自引:0,他引:1
在磷酸介质中,过氧化氢存在下,加入少量Cu2+的盐酸异丙肾上腺素试液经80℃水浴加热处理后与高碘酸钠反应产生强烈的化学发光.据此,结合流动注射技术建立了一种测定盐酸异丙肾上腺素的化学发光分析新方法.方法的线性范围为1.0×10-9~7.0×10-7 g/mL,检出限为4.0×10-10g/mL,相对标准偏差为3.0%(1.0×10-8g/mL盐酸异丙肾上腺素,n=11).该法用于注射液中盐酸异丙肾上腺素的测定,回收率为97%~103%. 相似文献
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盐酸中La3+与NO3-离子对铝的缓蚀作用 总被引:1,自引:0,他引:1
用失重法和电化学方法研究了La^3 与NO3^-对铝的缓蚀作用。研究表明:铝在加有Lan的盐酸介质中,腐蚀受到轻微抑制,并且La^3 浓度对铝缓蚀的影响不显著。而若盐酸溶液中同时存在有La^3 与NO3^-,铝的腐蚀则大大地受到抑制,表面覆盖度与缓蚀剂浓度的关系符合Langmuir等温吸附方程,动电位极化实验表明La^3 与NO3^-主要抑制了铝腐蚀的阴极反应,La^3 与NO3^-的存在与否并没改变H^ 阴极放电的机理。不同浓度HCl介质中,La^3 与NO3^-在相同腐蚀时间下对铝的缓蚀率不同;在一定浓度HCl介质中,La^3 与NO3^-在不同腐蚀时间下对铝的缓蚀率亦不同。 相似文献
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盐酸之用途甚广,为重要工业原料之一;如酱油、味精之制造,铁板(?)除锈,氯化物及医药之制造皆用以为原料。盐酸之制法很多,如;1.食盐加硫酸分解法:2NaCl+H_2SO_4→Na_2SO_4+2HCl↑2.哈革来夫(Hargreaves)法:2NaCl+SO_2+O+H_2O→Na_2SO_4+2HCl(?)3.水蒸汽分解氯化物法:MgCl_2+H_2O→MgO+2HCl↑4.合成法:Cl_2+H_2→2HCl↑5.副生法:有机化合物氯化时副产大量盐 相似文献
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盐酸在国民經济中具有重大作用,它在化学工業中有着广闊的用途,它被用为基本原料来制造更多的产物,例如,氯化銨、氯化鋇、氯化鎂、氯化鋅等一些氯化物的制造。而盐酸的更大价值是用於白金、黄金、銀的水力冶金电铸中的浸蝕,木質纖維的水解,酒精的生产,皮革的鞣制和染色,棉布的染印,和在染料、醋酸、可塑物等等的生产中。 相似文献
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氟化钠及氯化钠由水至水与二氧六圜混合溶剂的标准转移Gibbs能及活度系数的测定——应用离子选择电极研究溶液热力学 总被引:4,自引:2,他引:4
本文应用钠离子玻璃电极分别和氟离子及氯离子选择性电极组成无液接界可逆电池Na~+玻璃电极| MX(m) | |H_2O或混合溶剂|X~-选择性电极测定电池在NaF-H_2O-1,4-(CH_2)_4O_2(二氧六圜)及NaCl-H_2O-1,4-(CH_2)_4O_2体系的标准电动势, 计算NaF及NaCl由水至水-二氧六圜混合溶剂的转移Gibbs能及盐在不同组成溶液中的活度系数。并将NaCl-H_2O-1,4-(CH_2)_4O_2体系的△E_t~·的测定值与文献值进行比较, 结果进一步表明应用离子选择性电极进行溶液热力学研究是可靠的, 此外, 将本文的结果与以前的工作比较, 讨论了溶剂对△G_t°的影响。 相似文献
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本文在恒定异丙醇摩尔分数x=0.05的条件下, 应用电动势法测定无液体接界电池(A)和电池(B)的电动势:Pt, H_2(latm)|HCl(m), 2-propanol(x), H_2O(1-x)|Agcl-Ag (A)和Pt, H_2(latm)|HCl(m_A), NaCl(m_B), 2-propanol(x), H_2O(1-x)|AgCl-Ag (B)根据电池(A)电动势确定混合溶剂中的Ag-AgCl电极的标准电极电势, 讨论了HCl的迁移性质; 利用电池(B)电动势确定HCl在该体系中的活度系数γ_A, 在恒定总离子强度下, HCl的活度系数遵守Harned规则。在溶液组成恒定时, logγ_A是温度倒数1/T的线性函数, 讨论了混合物中HCl的相对偏摩尔焓, 计算了HCl的一级、二级和总介质效应。 相似文献
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水-醋酸体系中HCl的热力学性质研究 总被引:1,自引:0,他引:1
人们对混合溶剂中的电解质热力学性质虽然已进行了较广泛的实验研究,并提供了许多实验数据,为理论研究提供了方便,但还很不全面,即使象水-醋酸这样的混合溶剂体系,至今尚未见较全面的报道,为此,本文设计了如下电池:玻璃电极(H+)|HCl(m),HAc+H2O|AgCl-Ag并测定该电池的电动势,以了解HCl在水-醋酸中的热力学行为及离子-溶剂相互作用特点。 相似文献
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The thermodynamic properties of HCl-NaCl-d-Glueose-H_2O system was studied by emf measurement without liquid junction. Pt, H_2(1.013×10~5 Pa)|Hel(m), d-Glucose(x), H_2O(1-x)| Agel-Ag (A) Pt, H_2(1.013×10~5Pa)|HCl(m_A), NaCl(m_B), d-Glucose(x), H_2O(1-x)|AgCl-Ag (B) at the mass percentage of d-Glucose x=5%, 15% and 20% in the mixed solution, from 5 to 45 ℃, for cell (B) at constant total ionic strength I=1.00 mol·kg~(-1). The standard electrode potential of Ag-AgCI in the mixed solution have been determined from cell (A). The activity coefficients of HCl, γ_A, in the mixed solution system have been determined from cell (B). The results show that the activity coefficients of HCl in HCl-NaCl solutions still obeye Harned Rule. The standard transfer Gibbs free energies of HCl have calculated. The primary, secondary and total medium effect of HCl have been calculated. 相似文献
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Nielsen TB Hvidt S Keiding SR Petersen C Westh P Keiding K 《Physical chemistry chemical physics : PCCP》2011,13(3):1182-1188
Interactions between methyl tert-butyl ether (MTBE) and water have been investigated by scanning calorimetry, isothermal titration calorimetry, densitometry, IR-spectroscopy, and gas chromatography. The solubilization of MTBE in water at 25 °C at infinite dilution has ΔH° = -17.0 ± 0.6 kJ mol(-1); ΔS° = -80 ± 2 J mol(-1) K(-1); ΔC(p) = +332 ± 15 J mol(-1) K(-1); ΔV° = -18 ± 2 cm(3) mol(-1). The signs of these thermodynamic functions are consistent with hydrophobic interactions. The occurrence of hydrophobic interaction is further substantiated as IR absorption spectra of MTBE-water mixtures show that MTBE strengthens the hydrogen bond network of water. Solubilization of MTBE in water is exothermic whereas solubilization of water in MTBE is endothermic with ΔH° = +5.3 ± 0.6 kJ mol(-1). The negative mixing volume is explained by a large negative contribution due to size differences between water and MTBE and by a positive contribution due to changes in the water structure around MTBE. Henry's law constants, K(H), were determined from vapor pressure measurements of mixtures equilibrated at different temperatures. A van't Hoff analysis of K(H) gave ΔH(H)° = 50 ± 1 kJ mol(-1) and ΔS(H)° = 166 ± 5 J mol(-1) K(-1) for the solution to gas transfer. MTBE is excluded from the ice phase water upon freezing MTBE-water mixtures. 相似文献
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乙二醇和水混合溶剂多组分电解质热力学 总被引:4,自引:0,他引:4
在乙二醇和水混合溶剂中恒定乙二醇质量分数w=0.1的条件下,应用经典的电动势方法测定无液体接界电池的电动势:
Pt,H2 (105 Pa )│HCl (质量摩尔浓度m), C2H6O2 (w), H2O (1-w)│AgCl-Ag (A)
Pt,H2 (105 Pa )│HCl (mA), NaCl(mB), C2H6O2 (w), H2O (1-w)│AgCl-Ag (B)
根据测得电池(A)的电动势,确定混合溶剂中AgCl-Ag电极的标准电极电势,讨论了HCl的迁移性质.利用电池(B)的电动势,计算出HCl的活度系数γA.结果表明,在溶液中总离子强度保持恒定, HCl的活度系数服从Harned规则.在溶液组成恒定时, lgγA是温度倒数1/T的线性函数. 进一步讨论了混合物中HCl的相对偏摩尔焓和介质效应. 相似文献
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M.M. Elsemongy 《Journal of Electroanalytical Chemistry》1978,90(1):87-95
The electromotive force measurements of the cell Pt, H2 (gas, 1 atm); HCl (m), X % Bu tOH, Y% H2O; AgCl, Ag, at nine different temperatures ranging from 15 to 55°C at 5° intervals, have been used to determine the standard potentials of the silver-silver chloride electrode in eighteen tert-butyl alcohol+water solvent mixtures containing up to 90 wt. % alcohol. The standard molal potentials in each solvent have been represented as a function of temperature. The standard thermodynamic functions for the cell reaction, the primary medium effects of various solvents upon HCl, and the standard thermodynamic quantities for the transfer of one mole of HCl from water to tert-butyl alcohol+water media have been evaluated. The results have been discussed in the light of ion-solvent interactions as well as the structural changes of the solvents. 相似文献
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用量子化学从头计算方法研究了2-羟基-1-氧基乙烯自由基的质子转移反应。首先, 在UHF/3-21G的水平上, 采用能量梯度法优化了反应物和过渡态的几何构型, 然后利用这两个优化的构型做了振动分析, 找出相应的振动频率和模式, 从而得到质子转移反应的活化熵值。此外, 又做了内禀反应坐标途径(IRC)。为了求得比较准确的反应势能剖面, 以便进行隧道效应校正, 用多体微扰法(二级微扰)同时在参加转移的氢原子上附加了扩散函数p(UMP_2/3-21G~+)在IRC的各点上进行能量校正。根据从以上计算结果拟合的抛物线势, 求出质子转移的隧道效应校正系数为19.9, 然后由过渡状态理论计算了此反应的比速常数为7.4×10~(11)s~(-1)。此外, 还得到了该自由基的分子内氢键键能和键长分别为19.2 kJ mol~(-1)和0.2057 nm(UMP_2/3-21G~+结果)。 相似文献
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Hanken BE Shvareva TY Grønbech-Jensen N Stanek CR Asta M Navrotsky A 《Physical chemistry chemical physics : PCCP》2012,14(16):5680-5685
Cation mixing energetics in urania-ceria solid solutions with stoichiometric oxygen concentrations (U(1-y)Ce(y)O(2)) have been measured by high-temperature oxide-melt drop-solution calorimetry. Measurements have been performed on eight samples with compositions spanning y = 0.119 to y = 0.815. The measured mixing enthalpies (ΔH(mix)) range from -0.6 ± 3.3 to 3.9 ± 3.0 kJ mol(-1). These values are discussed in the context of results from atomistic modeling which take into consideration the possibility of charge transfer between uranium and cerium cations to form solid solutions with mixed charge states. A comparison between measured and calculated results for ΔH(mix) suggests that such charge transfer takes place to a limited extent in the most concentrated mixtures studied. 相似文献
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在恒定丙三醇质量分数x=0.1的条件下,测定了无液接电池(A)和电池(B)的电动势根据电池(A)电动势确定了丙三醇和水混合溶剂中的Ag-AgCl电极的标准电极电势,讨论了HCl的迁移性质;由电池(B)测得的电动势计算了HCl在该体系中的活度系数γA,计算的结果表明,对于所讨论的体系,在溶液中总离子强度保持恒定,HCl的活度系数服从Harned规则.在溶液组成恒定时,IgγA是温度倒数1/T的线性函数,讨论了混合物中HCl的相对偏摩尔焓及介质效应. 相似文献