Yu. B. Tsaplev

Chemiluminescence Determination of Hydrogen Peroxide

An overview of literature on the procedures for the chemiluminescence determination of hydrogen peroxide is presented.

Chemiluminescence quantum yield in permanganate reduction reactions in acid medium

Chemiluminescence quantum yields for the reactions of permanganate with oxalic, tartaric, and citric acids; hydrazine; KBr; and FeSO4 in aqueous solutions of sulfuric acid have been measured. The maximum quantum yield reaches 1.2 × 10−5 einstein/mol with the chemiexcitation yield being 2%. Hence, the relatively low chemiluminescence quantum yield is due to a low yield of light emission by chemiexcited particles, rather than the low chemiexcitation yield.

Chemiluminescence in reactions of manganese(III) reduction by lactic acid: Two-electron mechanism of chemiexcitation

Chemiluminescence is generated during reduction of manganese(III) ions with lactic acid to have a quantum yield as high as 0.1, a record-breaking chemi-excitation value for inorganic emitters. Kinetic features of the chemiluminescence and a nonradical mechanism of lactic acid oxidation lead to the conclusion that chemiexcitation results from two-electron reduction of manganese(IV) ions in the complex with lactic acid.

Phenomenological features of chemiluminescence in manganese(III) reduction reactions

Chemiluminescence is generated in the reduction reactions of Mn(III) in sulfuric acid solutions; however, it is absent during the reduction of Mn(III) with iron(II) sulfate or potassium bromide. The dependences of the light yield and the kinetic parameters of chemiluminescence upon the concentration of reagents have been determined for the reactions of Mn(III) reduction with malonic acid. The rate of Mn(III) consumption during the light pathway of the reaction (i.e., reaction that results in chemiexcitation) depends on the squared Mn(III) concentration. The light pathway loses in competition with the dark pathway. The chemiexcitation of Mn2+ follows either one- or two-electron mechanism, but the complex character of the reaction does not allow making selection between these two routes.

Dimethyl sulfoxide structuring in the presence of aqueous manganese(II) sulfate solution

Mixing of an aqueous MnSO4 solution with liquid dimethyl sulfoxide leads to gelation and loss of fluidity of the mixture.

Efficient Generation of Chemiluminescence during the reduction of manganese(IV) ions with lactic acid

The kinetics and mechanism of chemiluminescence during the reduction of manganese(IV) ions with lactic acid in an H2SO4–AcOH medium are studied. Kinetic spectrophotometric measurements are used to determine the profiles of change in the concentrations of Mn(IV) and Mn(III) ions during the reaction. The results from kinetic spectrophotometric measurements are compared to the light yield kinetics. The quantum chemiluminescence and chemiexcitation yields reach record values.

Role of chemiexcited particles in permanganate reduction by citric acid: Investigation with spectrophotometric and chemiluminescence methods

Potassium permanganate reduction by citric acid in the presence of sulfuric acid includes stages of chemigeneration of electronically excited Mn(II) and emission of photons by it. The electronic absorption, reactant concentration, and chemiluminescence kinetics have been investigated. It has been shown that the chemiexcited species Mn(II) (chemiluminescence emitter) acts as a permanganate reduction catalyst.

Photochemical transformations of anthraquinone in polymeric alcohols

It is established that the photolysis of anthraquinone in both aerated and deoxygenated polymeric alcohols is not accompanied by reduction with the formation of anthrahydroquinone; as a result, an adduct of hydroxyanthracene and polymeric alcohol is formed.

Decomposition of cyclic acetone peroxides in acid media

The kinetics and stoichiometry of the formation of active oxygen (AO) in the acidic decomposition of trimeric (TATP) and dimeric (DADP) cyclic acetone peroxides are considered. Fe(III) produced as a result of Fe(II) oxidation with active oxygen has been determined using rhodanide procedure. The kinetics of the formation of active oxygen is described by a first order equation. The effective rate constant of TATP decomposition depends on the Hammett acidity function H0: log keff = −H0 − 2.6 (keff is in s−1). Consequently, the decomposition rate of TATP is limited by protonation. In the HCl and H2SO4 concentration range from 0.006 to 2.9 mol/L, the decomposition of DADP occurs with keff = 0.0010 ± 0003 s−1 at a Fe(II) concentration of 3.5 mmol/L and keff depends linearly on the concentration of Fe(II).

Chemiluminescence during the oxidation of homogentisic acid

Chemiluminescence (CL) that accompanies the autooxidation of homogentisic acid in the presence of an alkali was studied. Data on the red shift of the CL spectrum at increased medium polarity and the dependence of the luminescence intensity and light efficiency on the reagent concentration were obtained. A CL emitter is supposed to be an excimer formed by two radical dianion molecules of homogentisic acid. Chemiluminescence of an excimer occurs during coproportionation.