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1.
A mixed gas of nitrogen, carbon dioxide, and hydrogen was discharged over 100 ml of 0.2M NaHCO3 solution in a 5 liter discharge apparatus which simulates the primitive Earth. The formation of cyanate, which is one of the possible primitive condensing agents, was demonstrated by the detection of [Cu(Py)2] (NCO)2 that was formed by the addition of copper sulfate-pyridine reagent to the solution. In a series of experiments the partial pressures of nitrogen and carbon dioxide in the starting gas were fixed at 10 cm Hg and 20 cm Hg, respectively, whereas that of hydrogen was varied between 5, 10, 15, 20, 25, and 30 cm Hg. The discharges were continued for one week. The rate of appearance of cyanate was strongly dependent upon the partial pressure of hydrogen. The maximum rate of the production of cyanate at the initial stage of the discharge was in the case of 10 cm Hg of hydrogen, in which condition the starting gas is in a predominantly oxidized state. In this case the concentration of cyanate reached about 0.012M after one day. Another discharge experiment was carried out with 0.2M phosphate solution, and the production of carbamyl phosphate was demonstrated through the formation of ATP by the incubation of the discharged solution with ADP and carbamyl phosphokinase. 相似文献
2.
N. S. Calgaroto G. Y. Castro D. Cargnelutti L. B. Pereira J. F. Gonçalves L. V. Rossato F. G. Antes V. L. Dressler E. M. M. Flores M. R. C. Schetinger F. T. Nicoloso 《Biometals》2010,23(2):295-305
Oxidative stress caused by mercury (Hg) was investigated in Pfaffia glomerata plantlets grown in nutrient solution using sand as substrate. Thirty-day-old acclimated plants were treated for 9 days with four Hg levels (0, 1, 25 and 50 μM) in the substrate. Parameters such as growth, tissue Hg concentration, toxicity indicators (δ-aminolevulinic acid dehidratase, δ-ALA-D, activity), oxidative damage markers (TBARS, lipid peroxidation, and H2O2 concentration) and enzymatic (superoxide dismutase, SOD, catalase, CAT, and ascorbate peroxidase, APX) and non-enzymatic (non-protein thiols, NPSH, ascorbic acid, AsA, and proline concentration) antioxidants were investigated. Tissue Hg concentration increased with Hg levels. Root and shoot fresh weight and δ-ALA-D activity were significantly decreased at 50 μM Hg, and chlorophyll and carotenoid concentration were not affected. Shoot H2O2 concentration increased curvilinearly with Hg levels, whereas lipid peroxidation increased at 25 and 50 μM Hg, respectively, in roots and shoots. SOD activity showed a straight correlation with H2O2 concentration, whereas CAT activity increased only in shoots at 1 and 50 μM Hg. Shoot APX activity was either decreased at 1 μM Hg or increased at 50 μM Hg. Conversely, root APX activity was only increased at 1 μM Hg. In general, AsA, NPSH and proline concentrations increased upon addition of Hg, with the exception of proline in roots, which decreased. These changes in enzymatic and non-enzymatic antioxidants had a significant protective effect on P. glomerata plantlets under mild Hg-stressed conditions. 相似文献
3.
Distribution of mercury, methyl mercury and organic sulphur species in soil, soil solution and stream of a boreal forest catchment 总被引:3,自引:0,他引:3
Concentrations of methyl mercury, CH3Hg (II), total mercury, Hgtot = CH3Hg (II) + Hg (II), and organic sulphur species were determined in soils, soil solutions and streams of a small (50 ha) boreal forest catchment in northern Sweden. The CH3Hg (II)/Hgtot ratio decreased from 1.2–17.2% in the peaty stream bank soils to 0.4–0.8% in mineral and peat soils 20 m away from the streams, indicating that conditions for net methylation of Hg (II) are most favourable in the riparian zone close to streams. Concentrations of CH3Hg (II) bound in soil and in soil solution were significantly, positively correlated to the concentration of Hgtot in soil solution. This, and the fact that the CH3Hg (II)/Hgtot ratio was higher in soil solution than in soil may indicate that Hg (II) in soil solution is more available for methylation processes than soil bound Hg (II). Reduced organic S functional groups (Org-SRED) in soil, soil extract and in samples of organic substances from streams were quantified using S K-edge X-ray absorption near-edge structure (XANES) spectroscopy. Org-SRED, likely representing RSH, RSSH, RSR and RSSR functionalities, made up 50 to 78% of total S in all samples examined. Inorganic sulphide [e.g. FeS2 (s)] was only detected in one soil sample out of 10, and in none of the stream samples. Model calculations showed that under oxic conditions nearly 100% of Hg (II) and CH3Hg (II) were complexed by thiol groups (RSH) in the soil, soil solution and in the stream water. Concentrations of free CH3Hg+ and Hg2+ ions in soil solution and stream were on the order of 10–18 and 10–32M, respectively, at pH 5. For CH3Hg (II), inorganic bi-sulphide complexes may contribute to an overall solubility at concentrations of inorganic sulphides higher than 10–9M, whereas considerably higher concentrations of inorganic sulphides (lower redox-potential) are required to increase the solubility of Hg (II). 相似文献
4.
《Journal of inorganic biochemistry》1986,26(1):23-33
Interaction between D-glucuronic acid and Zn(II), Cd(II), and Hg(II) metal ion salts has been studied in solution and solid complexes of the type M(D-glucuronate)X · nH2O and M(D-glucuronate)2·nH2O, where M = Zn(II), Cd(II), and Hg(II), X = Cl− or Br−, and n = 0–2 were isolated and characterized. Spectroscopic and other evidence indicated that in the metal-halide-sugar complexes the Zn(II) and Cd(II) ions bind to two D-glucuronate moieties via 06, 05 of the carboxyl oxygen atoms of the first and 04, 06' of hydroxyl and carbonyl groups of the second as well as to two H2O molecules, whereas in the corresponding M(D-glucuronate)2 · nH2O salts, the metal ions are bonded to two sugar anions through 06 and 06' of the ionized carboxyl groups and two water molecules, resulting in a six-coordination around each metal cation. The Hg(II) ion binds to 06 and 05 oxygen atoms of a sugar anion and to a halide anion or water molecule, in the Hg(D-glucuronate)X·nH2O compounds, while in the corresponding metal-glucuronate salt mercury is bonded to 06 and 06' of the two glucuronate anions with four-coordination around the Hg(II) ion. The β-anomer sugar conformation is predominant in the free acid and in these series of metal-sugar complexes. 相似文献
5.
The effects of nonmetabolic bacterial cell wall adsorption and the presence of bacterial exudates on the precipitation of mineral phases from solution is not well constrained experimentally. In this study, we measured the extent of Hg(II) removal from solution, in the presence and absence of nonmetabolizing cells of Bacillus subtilis in both Cl-free and Cl-bearing systems with Hg concentrations ranging from undersaturation to supersaturation with respect to montroydite [HgO(s)]. Total Hg molalities ranged from 10?5.00 to 10?2.00 M at pH 4.50 and 7.00; the ionic strength of the experiments was kept constant using 0.01 M NaClO4, and the wet mass of bacteria was held constant at 5 g/L for each biotic experiment.The biotic systems exhibited enhanced Hg(II) removal from solution relative to the abiotic controls in undersaturated conditions. However, thermodynamic modeling of the experimental systems strongly suggests that all of this Hg removal can be ascribed to Hg adsorption onto cell envelope functional groups. There was no evidence for enhanced Hg removal due to precipitation in bulk solutions that were undersaturated with respect to the solid phase. Under the highest total Hg concentrations studied in both the Cl-free and Cl-bearing systems, bacteria inhibit precipitation, maintaining high concentrations of Hg in solution. Cell-free, exudate-bearing control experiments suggest that aqueous complexation between Hg and the bacterially-produced exudates accounts for at least some of the precipitation inhibition. However, a comparison of total available binding sites on the exudates with the concentration of Hg in solution suggests that aqueous complexation alone can not account for the observed elevated final aqueous Hg concentrations in solution, and that the exudates likely exert a kinetic inhibition on the precipitation reaction as well. 相似文献
6.
A theoretical and experimental analysis of facilitated transport of CO2 across membranes containing NaHCO3 and the enzyme carbonic anhydrase (carbonate hydro-lyase EC 4.2.1.1) is presented. The necessary diffusion reaction equations are derived and the system constraints defined. For the CO2HCO3? system, mathematical simplifications based on the magnitude of various reaction and concentration terms are made to make the equations tractable to solution. The resultant equations are solved by a number of analytical and numerical techniques, each having a limited, though useful, range of validity.The experimental arrangement consists of a liquid membrane (created by soaking a porous filter paper in the test solution), a diffusion chamber, and gas metering and analysis equipment. Conditions were selected to cover the range from diffusion- to reaction-dominated behavior.The flux of CO2 across a membrane containing 1 M NaHCO3 was measured at various partial pressures of CO2 (2–28 in Hg) and with membrane thicknesses of 0.02, 0.06 and 0.10 cm. The extent of facilitation (defined as the ratio of reaction-related flux to the expected Fick's Law flux in the absence of reaction) ranged from near zero to nearly 5 in these experiments. The agreement between model calculations and experimental observation was found to be excellent over the entire range of near-diffusion to near-equilibrium behavior.In the presence of enzyme carbonic anhydrase (0.10 mg/ml, activity approx. 80%) and 1 M NaHCO3, the CO2 flux across a 0.02 cm membrane was 3–10-fold higher than the corresponding flux in the absence of enzyme. From experiments at various enzyme concentrations and membrane thicknesses, it appeared that the apparent CO2 reaction rate was directly proportional to the enzyme concentration. The model calculations for the enzyme-catalyzed reactions agreed with the experimental observations to within . 相似文献
7.
Competition between Fe(III)-Reducing and Methanogenic Bacteria for Acetate in Iron-Rich Freshwater Sediments 总被引:3,自引:0,他引:3
The kinetics of acetate uptake and the depth distribution of [2-14C]acetate metabolism were examined in iron-rich sediments from a beaver impoundment in northcentral Alabama. The half-saturation constant (Km) determined for acetate uptake in slurries of Fe(III)-reducing sediment (0.8 µM) was more than 10-fold lower than that measured in methanogenic slurries (12 µM) which supported comparable rates of bulk organic carbon metabolism and Vmax values for acetate uptake. The endogenous acetate concentration (S n) was also substantially lower (1.7 µM) in Fe(III)-reducing vs methanogenic (9.0 µM) slurries. The proportion of [2-14C]acetate converted to 14CH4 increased with depth from ca 0.1 in the upper 0.5 cm to ca 0.8 below 2 cm and was inversely correlated (r2 = 0.99) to a decline in amorphous Fe(III) oxide concentration. The results of the acetate uptake kinetics experiments suggest that differences in the affinity of Fe(III)-reducing bacteria vs methanogens for acetate can account for the preferential conversion of [2-14C]acetate to 14CO2 in Fe(III) oxide-rich surface sediments, and that the downcore increase in conversion of [2-14C]acetate to 14CH4 can be attributed to progressive liberation of methanogens from competition with Fe(III) reducers as Fe(III) oxides are depleted with depth. 相似文献
8.
Effects of Salicylic Acid on Heavy Metal-Induced Membrane Deterioration Mediated by Lipoxygenase in Rice 总被引:17,自引:0,他引:17
Deterioration of membranes caused by lipoxygenase (LOX) activity under 10 μM PbCl2 or 10 μM HgCl2 was partially alleviated by the exogenous application of 100 μM salicylic acid (SA). In two cultivars of rice (Oryza sativa
L. cvs. Ratna and IR 36), the presence of SA ameliorated the increased leakage of electrolytes, injury index, and the content
of malondialdehyde caused by these heavy metals. Lead decreased H2O2 content whereas Hg increased it in both cultivars. Application of SA increased H2O2 in presence of Pb, while decreased it in presence of Hg. Both Pb and Hg decreased superoxide dismutase activity, while increased
peroxidase activity. The activity of catalase was decreased by Hg but increased by Pb and SA reversed their effects. Thus,
SA ameliorated the damaging effects of Pb and Hg on membranes.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
9.
《生物化学与生物物理学报:生物膜》1987,900(1):45-55
The rotational spectrum of yeast cells changed after pre-treatment of the cells with HgCl2 or Hg(NO3)2 and became indistinguishable from that of ultrasonically produced cell walls. The spectrum of the affected cells contained a peak which could only be explained by attributing a conductivity to the cell walls that was higher than that of the medium. Theoretical models of the rotational response are fully in accord with the experimental spectra. It is shown that the rotation method is capable of measuring even the low cell wall conductivity of yeast cells (which was found to be 33 μS/cm at 10 μS/cm medium conductivity). Knowledge of the spectra allowed a field frequency to be selected at which untreated cells showed no rotation, but at which cells affected by treatment with Hg(II) identified themselves by rotating in the same direction as the field. Calculation of the percentage of cells showing this co-field rotation gave an index (termed the co-field rotation value) of the proportion of the cells that were affected. Using this technique, effects of 25 nmol/l Hg(II) could be demonstrated. In media of low conductivity (10 μS/cm) the change in the rotational spectrum was usually ‘all-or-none’, whereas at 200 μS/cm a graded Hg(II)-mediated change became apparent. The co-field rotation method showed that the action of small quantities of Hg(II) was still increasing after 3 h of incubation and paralleled the Hg(II)-induced K+ release. A rapid reduction of the effects of Hg(II) was seen when 3–30 mM K+ (or Na+) or when 1 mM Ca2+ were present in the incubation medium, or as the pH was increased. At high incubation cell concentrations the toxic effect of Hg(II) was reduced, apparently due to binding by the cells. 相似文献
10.
Study of the Spatial Distribution of Mercury in Roots of Vetiver Grass (Chrysopogon zizanioides) by Micro-Pixe Spectrometry 总被引:1,自引:0,他引:1
Cristina Lomonte Yaodong Wang Augustine Doronila David Gregory Alan J. M. Baker Rainer Siegele 《International journal of phytoremediation》2014,16(11):1170-1182
Localization of Hg in root tissues of vetiver grass (Chrysopogon zizanioides) was investigated by micro-Proton Induced X-ray Emission (PIXE) spectrometry to gain a better understanding of Hg uptake and its translocation to the aerial plant parts. Tillers of C. zizanioides were grown in a hydroponic culture for 3 weeks under controlled conditions and then exposed to Hg for 10 days with or without the addition of the chelators (NH4)2S2O3 or KI. These treatments were used to study the effects of these chelators on localization of Hg in the root tissues to allow better understanding of Hg uptake during its assisted-phytoextraction. Qualitative elemental micro-PIXE analysis revealed that Hg was mainly localized in the root epidermis and exodermis, tissues containing suberin in all Hg treatments. Hg at trace levels was localized in the vascular bundle when plants were treated with a mercury solution only. However, higher Hg concentrations were found when the solution also contained (NH4)2S2O3 or KI. This finding is consistent with the observed increase in Hg translocation to the aerial parts of the plants in the case of chemically induced Hg phytoextraction. 相似文献
11.
《Journal of inorganic biochemistry》1986,27(1):65-74
Interaction between l-arabinose and the zinc group metal-ion salts has been studied in aqueous solution and solid complexes of the type M(l-arabinose)X2·nH2O, where M = Zn(II), Cd(II), and Hg(II) ions, X = Cl− or Br−, and n = 0–2 have been isolated and characterized. On comparison with the structurally known Ca(l-arabinose) Cl2·4H2O and the corresponding magnesium compounds, it is concluded that the Zn(II) and Cd(II) ions are six-coordinated, binding to two arabinose moieties via 03, 04 of the first and 01, 05 of the second sugar molecule as well as to two H2O molecules. The Hg(II) ion binds only to two sugar molecules in a similar fashion to zinc and cadmium ions, resulting in a four coordination around the mercury ion. The strong intermolecular hydrogen bonding network of the free arabinose is rearranged to that of the sugar OH...H2O...halide system upon metalation. The β-anomer sugar conformation is predominant in the free sugar, while the α-anomer conformation is preferred by the alkaline earth and Zn(II), Cd(II), and Hg(II) cations. 相似文献
12.
Cristiane Lenz Dalla Corte Angélica Ramos Clarissa Marques Moreira dos Santos Valderi Luiz Dressler João Batista Teixeira da Rocha 《Biometals》2016,29(3):543-550
Organoseleno-compounds have been investigated for its beneficial effects against methylmercury toxicity. In this way, diphenyl diselenide (PhSe)2 was demonstrated to decrease Hg accumulation in mice, protect against MeHg-induced mitochondrial dysfunction, and protect against the overall toxicity of this metal. In the present study we aimed to investigate if co-treatment with (PhSe)2 and MeHg could decrease accumulation of Hg in liver slices of rats. Rat liver slices were co-treated with (PhSe)2 (0.5; 5 µM) and/or MeHg (25 µM) for 30 min at 37 °C and Se and Hg levels were measured by inductively coupled plasma mass spectrometry (ICP-MS) in the slices homogenate, P1 fraction, mitochondria and incubation medium. Co-treatment with (PhSe)2 and MeHg did not significantly alter Se levels in any of the samples when compared with compounds alone. In addition, co-treatment with (PhSe)2 and MeHg did not decrease Hg levels in any of the samples tested, although, co-incubation significantly increased Hg levels in homogenate. We suggest here that (PhSe)2 could exert its previously demonstrated protective effects not by reducing MeHg levels, but forming a complex with MeHg avoiding it to bind to critical molecules in cell. 相似文献
13.
Yutaka Suzuki Yoshiteru Harada Akinori Ueno Makoto Katori Haruya Okabe 《Prostaglandins & other lipid mediators》1986,32(3)
Filling of the gastric lumen of rats with 1.0 M NaCl solution (5 ml) for 10 min under urethane anesthesia caused an increase in the gastric fluid concentrations of prostaglandin (PG) E2, 13, 14-dihydro-15-keto-PGE2 and 6-keto-PGF1α as determined by radioimmunoassay. PGE2 was the major PG generated. The levels of PGE2 in the gastric fluid were increased dose-dependently after filling the lumen with 0.3, 0.5, 0.7 or 1.0 M NaCl solutions. The pH of the gastric fluid increased similarly after 0.5 to 1.0 M NaCl solutions. Indomethacin (10 mg/kg, i.p.) suppressed the PGE2 increase caused by 1.0 M NaCl solution, but did not prevent the increase of the pH of the gastric fluid induced by intragastric 1.0 M NaCl. Infusion of tetragastrin (62.5 μg/kg/hr, i.v., for 10 min) caused a marked increase of acid secretion without modifying intragastic concentration of PGE2. The acid secretion due to tetragastrin was completely inhibited after intragastric administration of 1.0 M NaCl solution, while indomethacin restored the tetragastrin-induced acid secretion, with prevention of a rise of intragastric PGE2 levels. These observations suggest that 1.0 M NaCl solutions suppress basal intragastric acid through a mechanism which is independent of prostaglandins. In contrast, the suppression of tetragastrin-induced acid secretion by intragastric 1.0 M NaCl solution appears to be mediated through a release of prostaglandins 相似文献
14.
Bente Christiansen Jens Pete Lomholt Kjell Johansen 《Environmental Biology of Fishes》1982,7(3):291-296
Synopsis Oxygen uptake (Vo
2) was measured in carp of approximately 40 cm length swimming at controlled variable oxygen tensions (Po
2). At Po
2> 120 mm Hg Vo
2 increased with an increase in swimming speed from 5.6 to 11.3 cm · sec–1. Extrapolation of Vo
2 to zero activity at Po
2 = 140 mm Hg revealed a standard O2 uptake of 36.7 ml O2 · kg–1 · h–1 at 20° C. At the lowest swimming speed (5.6 cm · s–1) the oxygen uptake increased when the water Po
2 was reduced. A near doubling in Vo
2 was seen at Po
2 = 70 mm Hg compared to 140 mm Hg. At higher swimming speeds in hypoxic water Vo
2 decreased relative to the values at low swimming speeds. As a result the slope of the lines expressing log Vo
2 as a function of swimming speed decreased from positive to negative values with decreasing Po
2 of the water. pH of blood from the caudal vein drawn before and at termination of swimming at Po
2 = 70 mm Hg and 100 mm Hg did not show any decrease in relation to rest values at Po
2 = 140 mm Hg. Blood lactate concentration did not increase during swimming at these tensions. 相似文献
15.
Mehdi Bouchouit Sofiane Bouacida Bachir Zouchoune Hocine Merazig Silvia Bua Zouhair Bouaziz 《Journal of enzyme inhibition and medicinal chemistry》2018,33(1):1150-1159
Three coordination compounds of formula {M(bmim)2Cl2} were synthetised (M?=?Co, Zn, and Hg) and fully characterised. Each complex incorporates 1-benzyl-2-methylimidazole (bmim) as ligand. The coordination polyhedron around the metal center for all complexes has a quasi-regular tetragonal geometry. Density functional theory calculations were carried out on the title compounds and as well on hypothetical complexes (Cu, Ni), in order to elucidate their electronic and molecular structure. The calculations reproduced the Co, Zn, and Hg experimental structures and could predict stable complexes in the case of Ni(II) and Cu(II) ions. The carbonic anhydrase (CA, EC 4.2.1.1) inhibitory effects of the three complexes were investigated. Only compound {Hg(bmim)2Cl2} (3) exhibited a modest inhibitory effect against hCA I, probably due to the affinity of Hg(II) for His residues at the entrance of the active site cavity. 相似文献
16.
Bernal-Uruchurtu MI Metta-Magaña AJ Guerrero-Álvarez JA Reyes-Martínez R Tlahuext H 《Carbohydrate research》2008,343(16):2804-2812
The reactivity of N-(2-aminophenyl)-d-glycero-d-gulo-heptonamide (adgha), with the group 12 cations, Zn(II), Cd(II), and Hg(II), was studied in DMSO-d6 solution. The studied system showed a selective coordination to Hg(II), and the products formed were characterized by 1H and 13C NMR in DMSO-d6 solution and fast atom bombardment (FAB+) mass spectra. The expected coordination compounds, [Hg(adgha)](NO3)2 and [Hg(adgha)2](NO3)2, were observed as unstable intermediates that decompose to bis-[2-(d-glycero-d-gulo-hexahydroxyhexyl)-benzimidazole-κN]mercury(II) dinitrate, [Hg(ghbz)2](NO3)2. The chemical transformation of the complexes was followed by NMR experiments, and the nature of the species formed is sustained by a theoretical study done using DFT methodology. From this study, we propose the structure of the complexes formed in solution, the relative stability of the species formed, and the possible role of the solvent in the observed transformations. 相似文献
17.
《Inorganica chimica acta》1988,150(1):113-118
Addition compounds of Hg(CF3)2 with [Ph4P]X and [Ph4As]X in the 1:1 ratio for X = Cl, Br, I as well as in the 1:2 ratio for X = SCN, were isolated from aquaeous solution and identified by elemental analysis and infrared spectroscopy. Molar conductance of the thiocyanate compounds in nitrobenzene solution points to its complex-salt nature defined as [Ph4P]2[Hg(CF3)2(SCN)2] and [Ph4As]2[Hg(CF3)2-(SCN)2], but not for the halide compounds. However, in the monoclinic crystals of the chloride ccompound, as shown by X-ray diffractometry, pairs of [Hg(CF3)2 molecules are bridged over by two chlorides in a centro-symmetrical dimer with the CHgC bond angle of 160.5(8)° and the Hg…Cl bond length of 2.823(3) and 2.837(4) Å. The structure was refined to the R factor of 0.053. When X = CN no addition compounds were obtained, the reaction products were HCF3 and the complex salts [Ph4P]2- [Hg(CN)]4 and [Ph4As]2[Hg(CN)]4, not described so far. 相似文献
18.
The potentiation or antagonistic effects of Cu, Hg, Pb and Cd salts in the presence of a long-acting anti-rheumatic drug, D-penicillamine (D.P.) were studied on cultured chondrocytes. CuSO4 (10–4M), HgCl2 (10–5M), Pb(CH3COO)2 (10–3M) and D.P. (10–3M) when used alone caused a small decrease in cell proliferation. The addition of D.P. with Cu, Hg or Pb salts resulted in a marked increase in the extent of growth inhibition. In contrast, CdCl2 (10–5M) produced an important growth inhibitory effect, and D.P. antagonized CdCl2 action. The CuSO4 D.P. toxicity was probably due to production of H2O2
in situ. To verify this hypothesis, catalase, responsible for H2O2 metabolism was used, and was found to partially reverse the inhibitory effect of CuSO4-D.P. 相似文献
19.
A Density Functional Theory method has been employed in this research to conduct an in-depth study of the correlation between the conversion of acetylene to vinyl chloride catalysed by MCl2 (M=Hg, Cd, Zn, Mn) and the electron affinity. From the analysis of the adsorption energy and energy profile of acetylene hydrochlorination reaction, combined with Fukui indices and outer-shell Mulliken population change alongside reaction pathway, it can be concluded that, the outermost electron migration is the main factor affecting the catalytic property of MCl2 (M=Hg, Cd, Zn, Mn) catalyst. The Mulliken population change of the central atom M2+ (M=Hg, Cd, Zn) share similar tendency along the reaction pathway, the only difference is Hg2+ gained more electrons than the other two when acetylene got absorbed, and that proved that Hg(II) got better electron withdrawing, which is a main motivator of better catalytic properties in acetylene hydrochlorination reaction. 相似文献
20.
A mixed gas of nitrogen, carbon dioxide, and hydrogen was discharged over 100 ml of 0.2 M NaHCO3 solution in a 5 liter discharge apparatus which simulates the primitive Earth. The formation of cyanate, which is one of the possible primitive condensing agents, was demonstrated by the detection of [Cu(Py)2] (NCO)2 that was formed by the addition of copper sulfate-pyridine reagent to the solution. In a series of experiments the partial pressures of nitrogen and carbon dioxide in the starting gas were fixed at 10 cm Hg and 20 cm Hg, respectively, whereas that of hydrogen was varied between 5, 10, 15, 20, 25, and 30 cm Hg. The discharges were continued for one week. The rate of appearance of cyanate was strongly dependent upon the partial pressure of hydrogen. The maximum rate of the production of cyanate at the initial stage of the discharge was in the case of 10 cm Hg of hydrogen, in which condition the starting gas is in a predominantly oxidized state. In this case the concentration of cyanate reached about 0.012 M after one day. Another discharge experiment was carried out with 0.2 M phosphate solution, and the production of carbamyl phosphate was demonstrated through the formation of ATP by the incubation of the discharged solution with ADP and carbamyl phosphokinase. 相似文献