Electrochemical oxidation reactions of L ascorbic acid(AA) at a copper cobalt hexacyanoferrate modified electrode(CoCuHCF/Pt) in neutral solutions were studied in comparison with that at a bared Pt electrode by in sit...Electrochemical oxidation reactions of L ascorbic acid(AA) at a copper cobalt hexacyanoferrate modified electrode(CoCuHCF/Pt) in neutral solutions were studied in comparison with that at a bared Pt electrode by in situ FTIR reflection absorption spectroscopy(FTIRRAS). The results indicated that the electrode oxidation of AA at both the electrodes CoCuHCF followed by chemical processes. AA is oxidized to dehydro L ascorbic acid(DHA) followed by a chemical hydration process. At Pt electrode, the DHA underwent hydration reaction to form bicyclic product, which then further was transformed into 2,3 diketogulonic acid and its enol form via an opening of lactone ring. However, at CoCuHCF/Pt electrode, the DHA undergoes ring opening reaction and then degradation reaction.展开更多
It is reported in this paper that a tetraazamacrocyclic nickel complex NiL(CIO4,)2, where L is 2, 4, 4, 9, 11, 11-hexamethyl-1, 5, 8, 12 -tetraazacyclotetradeca- 1, 5, 8, 12- tetraene, can serve as oscillating catalys...It is reported in this paper that a tetraazamacrocyclic nickel complex NiL(CIO4,)2, where L is 2, 4, 4, 9, 11, 11-hexamethyl-1, 5, 8, 12 -tetraazacyclotetradeca- 1, 5, 8, 12- tetraene, can serve as oscillating catalyst in the system of NaBrO3-Pyr-H2SO4. The ranges of initial concentration of main reactants in the system were obtained. The influence of temperature, Vc, Br-, Ag+, Hg2+, acetonitrile or acrylamide on the oscillations were discussed. The results indicated that Br- played an important role controlling reaction progress and some free radicals.Br2 may be involved in the reaction process. The stirring rate can affect oscillating reactions. The oscillation trajectories of this system were recorded. They are different from classical BZ reactions and some other tetraazamacrocyclic complexes catalyzed systems. The mechanism is briefly discussed.展开更多
A novel dioxime, N,N bis[2 (2 iminohydroxyphenoxy)ethyl] toluenesulfonamide(BIHET), was synthesized and characterized, and a carbon paste electrode modified with BIHET was employed for electroanalysis of iron(Ⅲ) from...A novel dioxime, N,N bis[2 (2 iminohydroxyphenoxy)ethyl] toluenesulfonamide(BIHET), was synthesized and characterized, and a carbon paste electrode modified with BIHET was employed for electroanalysis of iron(Ⅲ) from aqueous solutions. The electrochemical redox reaction of the dioxime with the modified CPE and the electrochemical behavior of iron(Ⅲ) on the CPE were investigated.展开更多
New oscillating reactions catalyzed by a bistetraazacrocyclic nickel (Ⅱ) complex Ni2L(ClO4), where L is bis(11,13 dimethyl 1,4,7,10 tetraza 10,13 cyclotridecadien 12 ylidene), in acidic bromate medium have been studi...New oscillating reactions catalyzed by a bistetraazacrocyclic nickel (Ⅱ) complex Ni2L(ClO4), where L is bis(11,13 dimethyl 1,4,7,10 tetraza 10,13 cyclotridecadien 12 ylidene), in acidic bromate medium have been studied. We obtained the concentration ranges of main reactant within which the oscillations were observed in the system. We discussed the influence of temperature, Vc ,Br-, Ag+, Hg2+, acetonitrile or acrylamide on the oscillations. The results indicated that Br-played an important role in the control reaction progress and free radical might be involved in the reaction process. We recorded the oscillation trajectories of this system. It was different from classical BZ reaction and some other tetraazamacrocyclic complexes catalyzed system.展开更多
文摘Electrochemical oxidation reactions of L ascorbic acid(AA) at a copper cobalt hexacyanoferrate modified electrode(CoCuHCF/Pt) in neutral solutions were studied in comparison with that at a bared Pt electrode by in situ FTIR reflection absorption spectroscopy(FTIRRAS). The results indicated that the electrode oxidation of AA at both the electrodes CoCuHCF followed by chemical processes. AA is oxidized to dehydro L ascorbic acid(DHA) followed by a chemical hydration process. At Pt electrode, the DHA underwent hydration reaction to form bicyclic product, which then further was transformed into 2,3 diketogulonic acid and its enol form via an opening of lactone ring. However, at CoCuHCF/Pt electrode, the DHA undergoes ring opening reaction and then degradation reaction.
文摘It is reported in this paper that a tetraazamacrocyclic nickel complex NiL(CIO4,)2, where L is 2, 4, 4, 9, 11, 11-hexamethyl-1, 5, 8, 12 -tetraazacyclotetradeca- 1, 5, 8, 12- tetraene, can serve as oscillating catalyst in the system of NaBrO3-Pyr-H2SO4. The ranges of initial concentration of main reactants in the system were obtained. The influence of temperature, Vc, Br-, Ag+, Hg2+, acetonitrile or acrylamide on the oscillations were discussed. The results indicated that Br- played an important role controlling reaction progress and some free radicals.Br2 may be involved in the reaction process. The stirring rate can affect oscillating reactions. The oscillation trajectories of this system were recorded. They are different from classical BZ reactions and some other tetraazamacrocyclic complexes catalyzed systems. The mechanism is briefly discussed.
文摘A novel dioxime, N,N bis[2 (2 iminohydroxyphenoxy)ethyl] toluenesulfonamide(BIHET), was synthesized and characterized, and a carbon paste electrode modified with BIHET was employed for electroanalysis of iron(Ⅲ) from aqueous solutions. The electrochemical redox reaction of the dioxime with the modified CPE and the electrochemical behavior of iron(Ⅲ) on the CPE were investigated.
文摘New oscillating reactions catalyzed by a bistetraazacrocyclic nickel (Ⅱ) complex Ni2L(ClO4), where L is bis(11,13 dimethyl 1,4,7,10 tetraza 10,13 cyclotridecadien 12 ylidene), in acidic bromate medium have been studied. We obtained the concentration ranges of main reactant within which the oscillations were observed in the system. We discussed the influence of temperature, Vc ,Br-, Ag+, Hg2+, acetonitrile or acrylamide on the oscillations. The results indicated that Br-played an important role in the control reaction progress and free radical might be involved in the reaction process. We recorded the oscillation trajectories of this system. It was different from classical BZ reaction and some other tetraazamacrocyclic complexes catalyzed system.
