共查询到19条相似文献,搜索用时 187 毫秒
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亚氯酸盐-硫代硫酸盐非缓冲体系的动力学 总被引:11,自引:0,他引:11
研究了亚氯酸盐-硫代硫酸盐反应体系在非缓冲条件下的复杂动力学行为.结果发现,在开放体系中反应的pH值和Pt电位存在准周期振荡分叉和混合模式振荡分叉通向混沌的过程,且pH峰与Pt电位峰反相位.当与起始浓度比相对较小时,随着流速的逐渐升高,体系的pH值和Pt电位从简单的小振幅振荡(S)经过准周期振荡分叉到混沌,最后回到简单大振幅振荡(L);而当与起始浓度比相对较高时,随着流速的降低,体系的pH值和Pt电位出现LS1、LS2、LS3…LSn的混合模式振荡,并在每对(LSn、LSn+1)振荡区间发现了LSn、LSn+1随机出现的非周期振荡行为.运用硫价态变化的一般动力学模型,模拟出了反应体系的混合模式振荡及非周期振荡. 相似文献
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Na_2S_2O_3与过氧化合物之间的非线性化学反应研究 总被引:1,自引:0,他引:1
研究了Na_2S_2O_3与过氧化合物(H_2O_2和Na_2S_2O_8)的反应在batch和CSTR中的动力学情况,发现无催化剂时在CSTR中Na_2S_2O_3被H_2O_2和Na_2S_2O_8氧化有稳态振荡出现,在Na_2S_2O_3-H_2O_2-H_2SO_4反应体系中振荡范围外高低流速体系稳定定态(Pt电位和pH)皆处在振荡反应同一极值状态边,Cu~(2+)催化反应中有可分离的催化振荡过程和无催化振荡过程.在实验的基础上提出3个阶段反应机制:氢离子正反馈反应、负反馈反应(非催化负反馈和催化负反馈)及过渡反应,可合理解释硫代硫酸钠被过氧化合物氧化过程中出现的非线性化学现象. 相似文献
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研究了在非缓冲介质中高碘酸盐氧化硫脲的复杂反应动力学。实验结果表明:高碘酸盐氧化硫脲的非线性反应不但呈现多种不同的化学计量方程式,而且体系的pH、[I-]、[I2]及Pt电极电位呈现封闭条件下的准振荡和单峰振荡以及开放条件下的双稳态和衰减振荡行为。综合考虑硫价态与碘价态变化的各自非线性过程及相互耦合,提出了包含质子快速预平衡反应、碘化合物自身反应、碘化合物-硫化合物反应以及硫-硫反应的12步反应机理,模拟出了封闭体系中pH、[I-]以及[I2]的准振荡和单峰振荡以及开放体系中的双稳态行为。 相似文献
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研究了 KIO3-KSCN-H+反应体系在连续搅拌流动反应器 ( CSTR)中的非线性动力学行为 .在 CSTR中 ,该反应体系的 Pt电极电位显示出持续振荡现象 ,振荡的浓度范围非常宽 .通过酸度及各种金属离子对体系振荡行为影响的研究发现 ,对振荡体系具有催化作用的可能物种是 H+ 离子而不是金属离子 相似文献
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研究了在非缓冲介质中碘酸盐氧化硫脲的复杂动力学行为, 结果发现在封闭条件下体系的pH, [I8722;]及铂电极电位呈现单峰或准振荡现象. 当碘酸盐过量时, 体系的pH首先快速上升, 然后自催化下降, 最后上升趋向平缓, 体系碘钟产生的诱导期与体系初始pH成正比; 而当硫脲过量时, 体系的pH呈现单峰振荡行为并伴随着I2瞬时产生与瞬时消耗的过程, [I2]到达极值的诱导期与体系初始pH呈线性关系. 运用包含质子平衡反应、碘钟反应、碘-硫反应以及硫-硫反应的14步反应机理模拟出了封闭体系中pH, [I8722;]以及[I2]的单峰振荡或准振荡行为. 相似文献
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KIO3-KSCN-H+反应体系的非线性动力学研究 总被引:1,自引:0,他引:1
研究了KIO3-KSCN-H+反应体系在连续搅拌流动反应器(CSTR)中的非线性动力学行为.在CSTR中,该反应体系的Pt电极电位显示出持续振荡现象,振荡的浓度范围非常宽.通过酸度及各种金属离子对体系振荡行为影响的研究发现,对振荡体系具有催化作用的可能物种是H+离子而不是金属离子. 相似文献
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Kinetics of reaction between Na2S2O3 and peroxide compound ( H2O2 or Na2S2O8) in a batch reactor and in a continuous stirring tank reactor (CSTR) were studied.Steady oscillations in uncatalyzed reactions in a CSTR were first discovered.In Na2S2O3-H2O2-H2SO4 reaction system,Pt potential and pH of higher and lower flow rutes beyond oscillation flow rates were in around the same extreme values.The reaction catalyeed by Cu2+ corsist of the catalyzed oscillation process and the uncatalyzed osciliation one.On the basis of experiment,a reaction mechanism consisting of three stages was put forward.The three stages are H positive-feedback reactions,proton negative-feedba k (uncatalyzed negative-feedback and catalyzed negative-feedback) reactions and transitional reactions.The mechanism is able to explain reasonably the nonlinear chemical phenomena appearing in the thiosulfatc oxidation reaction by peroxide-compounds. 相似文献
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Two kinds of different mechanistic oscillations can be displayed in the H_2O_2-KSCN-CuSO_4-NaOH system. One discovered by this study is the pH oscillation in a continuous flow stirred tank reactor(CSTR) resulting from the oxidation of KSCN. The other is the oscillation of H_2O_2 decomposition in both CSTR and batch reactors(reported by Orbáin in 1986). Under appropriate experimental conditions, the system exhibits a birhythmicity in a CSTR. Two different pH oscillations are reported here. The pH oscillations which accompany the decomposition of H_2O_2 exist in the batch reactor and the CSTR at a high flowrate, but the pH oscillations in a CSTR at a low flowrate originates from proton positive and negative feedback in the oxidation of KSCN. The oscillation of non-catalyzed oxidation of KSCN by hydrogen peroxide in a CSTR can be found. Also we have observed whether Cu~(2+) exists or not in the batch system, the pH increases to near neutral ultimately after pH drops twice. 相似文献
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高碘酸盐-硫脲-硫酸反应体系的非线性动力学 总被引:2,自引:0,他引:2
研究了KIO4 SC(NH2)2 H2SO4反应体系在封闭、半封闭以及开放系统中的非线性动力学行为.发现在封闭体系中体系的吸光度、铂电极电位和pH值呈现单峰或准振荡现象;在半封闭和开放系统中体系的铂电极电位和碘电极电位均呈振荡现象.封闭、半封闭及开放系统的动力学曲线受体系酸度和初始浓度比值[KIO4]0/[SC(NH2)2]0的影响.对照其在封闭、半封闭和开放系统中的动力学行为,以碘单质产生和消耗驱使的反应动力学可解释该反应体系的复杂现象. 相似文献
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亚氯酸盐-硫脲反应体系的非线性动力学 总被引:2,自引:0,他引:2
The reaction between chlorite and thiourea could display batch oligooscillation and CSTR oscillation of pH.Batch pH peak has the same character with pH oscillation in a CSTR.The oxidation of thiourea produced intermediates such as HOSC(NH)NH2,HO2SC(NH)NH2,HO3S(NH)NH2 and bisulfite.The valence change of sulfur has close relation with pH dynamics.Through the mechanistic analysis,a general model of sulfur(- II) oxidation,which consists of negative hydrogen ion feedback(S(- II) to S(0)),a transition process of S(0) to S(IV) and positive proton feedback from S(IV) to S(VI),could simulate batch oligooscillation and CSTR oscillation.This result is setting up a new channel to uncover the reaction mechanism and simulate the nonlinear phenomena in the reactions between chlorite and Sulfur(- II). 相似文献
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Qingyu Gao Yaomin Wang Guichang Wang Songlin Zhang Yaru Zang Xuezhuang Zhao 《中国科学B辑(英文版)》1997,40(2):152-160
Kinetics of reaction between Na2S203 and peroxide compound (H202 or Na2S2O3) in a batch reactor and in a continuous stirring tank reactor (CSTR) were studied. Steady oscillations in uncatalyzed reactions
in a CSTR were first discovered. In Na2S203-H2O2-H2S04 reaction system, Pt potential and pH of higher and lower flow rates beyond oscillation flow rates were in around the
same extreme values. The reaction catalyzed by Cu2+ consists of the catalyzed oscillation process and the uncatalyzed osciliation one. On the basis of experiment, a reaction
mechanism consisting of three stages was put forward. The three stages are H+ positive-feedback reactions, proton negative-feedback (uncatalyzed negative-feedback and catalyzed negative-feedback) reactions
and transitional reactions. The mechanism is able to explain reasonably the nonlinear chemical phenomena appearing in the
thiosulfate oxidation reaction by peroxide compounds.
Project supported by the National Natural Science Foundation of China. 相似文献
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Furfural, a byproduct formed during the thermal/chemical pre-treatment of hemicellulosic biomass, was degraded to methane
and carbon dioxide under anaerobic conditions. The consortium of anaerobic microbes responsible for the degradation was enriched
using small continuously stirred tank reactor (CSTR) systems with daily batch feeding of biomass pretreatment liquor and continuous
addition of furfural. Although the continuous infusion of furfural was initially inhibitory to the anaerobic CSTR system,
adaptation of the consortium occurred rapidly with high rates of furfural addition. Addition rates of 7.35 mg furfural/700-mL
reactor/d resulted in biogas productions of 375%, of that produced in control CSTR systems, fed the biomass pretreatment liquor
only. The anaerobic CSTR system fed high levels of furfural was stable, with a sludge pH of 7.1 and methane gas composition
of 69%, compared to the control CSTR, which had a pH of 7.2 and 77% methane. CSTR systems in which furfural was continuously
added resulted in 80% of the theoretically expected biogas. Intermediates in the anaerobic biodegradation of furfural were
determined by spike additions in serum-bottle assays using the enriched consortium from the CSTR systems. Furfural was converted
to several intermediates, including furfuryl alcohol, furoic acid, and acetic acid, before final conversion to methane and
carbon dioxide. 相似文献
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比较了批式反应器和连续流动搅拌反应器中酶动力学拆分萘普生的不同之处。从宏观反应器平衡角度,推导出了在CSTR中不同于在批式反应器中的酶立体选择性,产物对映体过量值和反应转化率的定量关系式,并通过脂肪酶催化的萘一甲酯的不对称水解反应得到了证实。 相似文献
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