共查询到19条相似文献,搜索用时 453 毫秒
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DL-苹果酸-丙酮-BrO~3^--Mn^2^+-H~2SO~4化学振荡 反应诱导期的新特征 及其动力学研究 总被引:1,自引:0,他引:1
在前文研究工作的基础上,较详细地研究了DL-苹果酸(以下简称DL-MA)、丙酮(以下简称Act)参与下的新型化学振荡反应及各种影响因素,对各主要参与反应物质在诱导期中的作用、起振原因、诱导期的新特征和可能反应机理进行了较为深入的研究,分别获得DL-MA,KBrO~3,MnSO~4的浓度对诱导期影响的拟合方程。以及诱导期的表观活化参数为E~I~N=68.50kJ·mol^-^1。 相似文献
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乳酸-丙酮-BrO3^——Mn^2^+-H2SO4化学振荡体系动力学研究 总被引:9,自引:0,他引:9
本文报道了与生命代谢过程密切相关的中间物参与的乳酸(以下简称LA)-丙酮(以下简称Act)-BrO3^--Mn^2^+-H2SO4新型化学振荡体系, 考察了振荡体系中诸反应物的初始浓度范围及影响因素, 获得诱导期、振荡周期、振荡寿命所对应的表观活化参数EIN, EP, EL分别为60.68kJ.mol^-^1, 61.03kJ.mol^-^1,135.80kJ.mol^-^1。分析了诱导期的新特征及可能的振荡反应机理。 相似文献
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首次报道了间歇釜中以丝氨酸(Ser)-BrO^-~3-Mn^2^+-H2SO4为体系(简称Ser-BZ体系)的新型BZ类振荡反应,其特征如下:(1)虽然Ser不能发生溴代反应,但即使在无丙酮或惰性气体流时也能在间歇釜中观察到持续振荡;(2)振荡诱导期极短(~0),振荡次数较少(<11次);(3)振荡反应受到Cl^-,Br^-,丙烯腈等的抑制;但当加入足够量Ag^+使[Br^-]的振荡抑制后,仍可在Pt电极上观察到振荡现象。根据上述特征和反应产物分析,推测Ser-BZ振荡反应可能是自由基-控制模型,而非Br^--控制模型。加入适量丙酮可诱导连续振荡反应,归因于两种控制模型的共存。通过对Mn^3^+-Ser和BrO^-~3-Mn^2^+反应的动力学研究,并结合FKN机理,对Ser-BZ振荡反应机理进行了初步讨论。 相似文献
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研究了Cu、K助剂对共沉淀型FeMn/SiO2催化剂还原行为、吸附行为及费托(F-T)合成活性和选择性的影响. Cu助剂以与Fe、Mn、SiO2共沉淀的方式引入, 而K助剂是在喷雾干燥前均匀加入沉淀浆料引入的. 结果表明, Cu可明显提高催化剂的还原性能, K助剂能促进催化剂在CO中的还原但抑制在H2中的还原, 而同时加入Cu和K会进一步促进催化剂在H2或CO中的还原; Cu助剂能促进H2吸附而K助剂对H2吸附无明显影响; Cu在一定程度上提高了F-T合成活性, 缩短了反应诱导期, K明显促进了CO的转化而相对抑制了H2的转化, 并且延长了反应的诱导期, Cu与K协同作用不仅提高反应的转化率而且缩短了反应的诱导期; K使得烃产物平均分子量增加, Cu单独对烃产物分布影响不明显, 而与K共同作用会进一步增加烃产物的分子量. 相似文献
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本文研究了BrO_3~--Br~--H~+-Mn~(2+)-衣康酸体系的振荡行为, 利用电位法及分光光度计对体系做了一系列测定, 根据FKN机理, 提出了本体系可能的反应进程, 同时测定了各种反应条件对振荡的诱导期及周期影响, 并根据机理分析把诱导期分成两个部分, 得到1/τ_(i1), 1/τ_(i2), 1/τ_p对各种反应物起始浓度的关系式。还发观葡萄糖能促进振荡进行。 相似文献
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丙酮酸作底物的BZ振荡体系 总被引:4,自引:0,他引:4
研究生命体系中物质参与的化学振荡对探索生物振荡规律,推动时间医药学的发展起着十分重要的作用。丙酮酸是动物体能量代谢过程和植物体光合过程的重要中间体。我们发现了以它作反应底物的BZ振荡体系:丙酮酸(Pyr)-溴酸钾(KBrO_3)-邻菲罗啉铁(Ⅱ)(Fe(phen)_3~(2+))-硫酸(H_2SO_4)体系。(以下简称Pyr-BZ体系)。并对这一振荡反应的影响因素及其 相似文献
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Ruhlmann L Canny J Vaissermann J Thouvenot R 《Dalton transactions (Cambridge, England : 2003)》2004,(5):794-800
Two new mixed-metal sandwich complexes [M(II)2(H2O)2Fe(III)2(P2W15O56)2]14- (abbreviated [M2Fe2P4W30], M(II) = Co(II), Mn(II)) were obtained at pH 3 by addition of M2+ to [Na2(H2O)2Fe(III)2(P2W15O56)2]16- (abbreviated [Na2Fe2P4W30]) without substitution in the alpha-[P2W15O56]12- (abbreviated [P2W15]) units. Their X-ray structures are reported. At lower pH, back conversion to [Na2Fe2P4W30] was followed by 31P NMR, electrochemistry and UV-visible spectroscopy. The preparation and the characterization in solution of the lacunary intermediate [NaCo(II)(H2O)2Fe(III)2(P2W15O56)2]15- (abbreviated [NaCoFe2P4W30]) is also described. 相似文献
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Low-frequency, high-amplitude pH-oscillations observed experimentally in the H2O2-HSO3(-)-S2O3(-) flow reaction system at 21.0 degrees C undergo period-doubling cascades to chemical chaos upon decreasing the temperature to 19.0 degrees C in small steps. Period-4 oscillations are observed at 20.0 degrees C and can be calculated on the basis of a simple model. A reverse transition from chaos to high-frequency limit cycle oscillations is also observable in the reaction system upon decreasing further the temperature step by step to 15.0 degrees C. Period-2 oscillations are measured at 18.0 degrees C. Such a temperature-change-induced transition between periodic and chaotic oscillatory states can be understood by taking into account the different effects of temperature on the rates of composite reactions in the oscillatory system. Small differences in the activation energies of the composite reactions are responsible for the observed transitions. Temperature-change-induced period doubling is suggested as a simple tool for determining whether an experimentally observed random behavior in chemical systems is of deterministic origin or due to experimental noise. 相似文献
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Sourisseau S Louvain N Bi W Mercier N Rondeau D Buzaré JY Legein C 《Inorganic chemistry》2007,46(15):6148-6154
The alpha1-(Br-(CH(2))(2)-NH(3))(2)PbI(4) hybrid perovskite undergoes a solid-state transformation, that is, the reaction between the organic cations and the perovskite layers to give the new hybrid perovskite (Br-(CH(2))(2)-NH(3))(2-x)(I-(CH(2))(2)-NH(3))(x)PbBr(x)I(4-x), based on mixed halide inorganic layers. This transformation has been followed by a conventional powder X-ray diffraction system equipped with a super speed detector, and both solid-state (13)C NMR and ESI/MS measurements have been adopted in the estimation of the rate of halide substitution. The first reaction step leads to the special composition of x approximately 1 (A phase), while the complete substitution is not achieved even at elevated temperature (x(max) approximately 1.85 (B phase)). This unprecedented solid-state reaction between organic and inorganic components of a hybrid perovskite can be considered as a completely new strategy to achieve interesting hybrid perovskites. 相似文献
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Srinivasa R. Pullela Jingyi Shen Manuel Marquez Zhengdong Cheng 《Journal of Polymer Science.Polymer Physics》2009,47(9):847-854
Environment‐sensitive poly(N‐isopropylacrylamide) (PNIPAM) microgel particles with covalently bonded ruthenium(4‐vinyl‐4′‐methyl‐2,2′‐bipyridine) bis (2,2′‐bipyridine) [Ru(vmbipy)(bipy)2] display periodic size changes when placed in Belousov‐Zhabotinsky (BZ) reaction substrates. The temperature dependency of the induction time and oscillatory frequency of the BZ reaction in this polymer‐immobilized catalyst system were compared to the bulk BZ reaction with the catalyst in the solution phase. Prolonged induction times are observed for the immobilized catalyst, compared with free catalyst, while little difference is observed on the oscillation frequency. The Arrhenius frequency factor calculated using the induction time for the immobilized catalyst BZ reaction is about seven times smaller than that for the free catalyst Ru(bipy) case. On the other hand, the Arrhenius frequency factors calculated using the oscillatory frequency are almost the same, showing similar reaction kinetics during the BZ oscillations. The tunability of the induction time using a polymer matrix, as we observed here, while maintaining similar oscillatory behavior, should provide a new dimension to control the self‐assembling of BZ active particles. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 47: 847–854, 2009 相似文献
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由Rossler反应系统的理论模型出发,构造一种具有外部周期扰动的新动力学系统,并采用逆算符法和数值分析法研究该系统的振荡态在周期扰动调制下的动力学行为.结果表明,在周期扰动的调制下,系统的状态由单周期振荡态(1p)变为周期2(2p)、周期4(4p)等多周期振荡态以及混沌态.扰动位相是系统呈现上述多种演化模式的控制参数,在扰动位相不同的数值区间,系统呈现的演化模式不同,而且扰动位相数值的微小改变,还影响每种演化模式的内部结构. 相似文献
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研究了显色剂4-氯-2-磺酸基苯基重氮氨基偶氮苯(CSDAA)的理化性质及其与Cd(Ⅱ)的高灵敏度显色反应。在TritonX-100存在下,于pH10.6的氨水-氯化铵缓冲介质中,该试剂与Cd(Ⅱ)形成31的红色络合物,最大吸收波长位于521nm处,Cd(Ⅱ)在0~20μg/25ml内符合比耳定律,表观摩尔吸光系教为2.0×10 相似文献