1184-90-3Relevant articles and documents
Kinetics and Mechanism of the Oxidation of Thiourea by Bromate in Acidic Solution
Simoyi, Reuben H.,Epstein, Irving R.,Kustin, Kenneth
, p. 551 - 557 (1994)
The reaction between bromate and thiourea has been studied in acidic medium.The stoichiometry of the reaction in excess thiourea is 4BrO3- + 3SC(NH2)2 + 3H20 -> 3SO42- + 3OC(NH2)2 + 4Br- + 6H+; in excess bromate the stoichiometry is 8BrO3- + 5SC(NH2)2 + H2O -> 5SO42- + 5OC(NH2)2 + 4Br2 + 2H+.No bromine is formed in excess thiourea.In excess bromate the reaction displays an initial induction period.At the end of the induction period, the redox potential of the reaction mixture rises sharply, sulfate appears (signaled by precipitation of BaSO4 when BaCl2 is initially added), and a yellow coloration (due to bromine) is first noticeable.Consequently, bromine is not formed until all thiourea is consumed.A 14-step mechanism is proposed and used to simulate the observed kinetics.The rate-determining step for bromine appearance is formation of HOBr from the BrO3--Br- reaction.The oxidation of thiourea proceeds via oxygen additions on sulfur, successively forming HOSC(NH)NH2, HO2SC(NH)NH2, HO3SC(NH)NH2, and SO42-.The mechanism requires that cleavage of the X-C bond to form urea and SO42- occur at the sulfonic acid level and not before, in agreement with experimental observation.
New and surprising experimental results from the oxidation of sulfinic and sulfonic acids
Makarov, Sergei V.,Mundoma, Claudius,Penn, John H.,Svarovsky, Serge A.,Simoyi, Reuben H.
, p. 6786 - 6792 (1998)
Thiourea, (H2N)2C=S, aminoiminomethanesulfinic acid, H2N(HN=)CSO2H (AIMSA), and aminoiminomethanesulfonic acid, H2N(HN=)CSO3H (AIMSOA) are all oxidized by mild oxidizing agents to a sulfate and an organic residue. AIMSA and AIMSOA are the postulated intermediates in the oxidation pathway of thiourea to sulfate. The oxidation of AIMSOA is accompanied by a cleavage of the C-S bond to form sulfate. Surprisingly, freshly prepared solutions of AIMSOA are oxidized by the common oxidants (oxyhalogens and halogens) at rates that are much slower than oxidation rates of AIMSA by the same oxidants. These results seem to suggest that AIMSOA may be structurally different from AIMSA and that the decomposition of AIMSOA to HSO3- is the prerequisite to its oxidation. The oxidation pathway of AIMSA to SO42- also proceeds through the formation of HSO3- and not predominantly through AIMSOA.
Oxyhalogen-Sulfur Chemistry: Oligooscillations in the Formamidinesulfinic Acid-Chlorite Reaction
Jones, Juan B.,Chinake, Cordelia R.,Simoyi, Reuben H.
, p. 1523 - 1529 (1995)
The reaction between chlorite and formamidinesulfinic acid has been studied in perchloric acid between pH 1 and 3.The stoichiometry of the reaction in excess chlorite is HO2SC(NH)NH2 + ClO2(-) + H2O --> SO4(2-) + OC(NH2)2 + Cl(-) + 2H(+) (A), while the stoichiometry in excess formamidinesulfinic acid is a mixture of (A) and (B): 2HO2SC(NH)NH2 + ClO2(-) --> 2HO3SC(NH)NH2 + Cl(-) (B).In excess chlorite at the end of the oxidation of formamidinesulfinic acid ClO2 is formed from the reaction 2ClO2(-) + HOCl + H(+) --> 2ClO2 + Cl(-) + H2O.The formation of ClO2 shows some oligooscillatory behavior in which, even in excess formamidinesulfinic acid, there is transient formation of ClO2.The reaction is autocatalytic in HOCl via the asymmetric Cl2O2 intermediate.The dynamics of the reaction are explained via a mechanism which is derived from the one used for the chlorite-thiourea reaction.
Kinetic study on hydrolysis and oxidation of formamidine disulfide in acidic solutions
Hu, Ying,Feng, Jiamin,Li, Yanwei,Sun, Yanyan,Xu, Li,Zhao, Yuemin,Gao, Qingyu
, p. 235 - 241 (2012)
Hydrolysis and oxidation of formamidine disulfide in acidic medium were investigated using high-performance liquid chromatography (HPLC) and mass spectrometry (MS) at 25 °C. By controlling the slow reaction rate and choosing appropriate mobile phase, HPLC provides the unique advantages over other methods (UV-Vis, chemical separation) in species tracking and kinetic study. In addition to thiourea and formamidine sulfinic acid, two unreported products were also detected in the hydrolysis reaction. Mass spectrometry measurement indicates these two products to be formamidine sulfenic acid and thiocyanogen with mass weights of 92.28 and 116.36, respectively. In the oxidation of formamidine disulfide by hydrogen peroxide, besides thiourea, formamidine sulfenic acid, formamidine sulfinic acid, thiocyanogen and urea, formamidine sulfonic acid and sulfate could be detected. The oxidation reaction was found to be first order in both formamidine disulfide and hydrogen peroxide. The rate constants of hydrolysis and oxidation reactions were determined in the pH range of 1.5-3.0. It was found both rate constants are increased with the increasing of pH. Experimental curves of different species can be effectively simulated via a mechanism scheme for formamidine disulfide oxidation, including hydrolysis equilibrium of formamidine disulfide and irreversible hydrolysis of formamidine sulfenic acid.
MONOSUBSTITUTED GUANIDINES FROM PRIMARY AMINES AND AMINOIMINOMETHANESULFONIC ACID
Kim, Keekyung,Lin, Yi-Tsong,Mosher, Harry S.
, p. 3183 - 3186 (1988)
Aminoiminomethanesulfonic acid, H2N-C(=NH)SO3H, converts primary amines to the corresponding guanidine derivatives at 20 deg C.This crystalline reagent is readily prepared by the peracetic acid oxidation of formamidinesulfinic acid, H2N-C(=NH)SO2H.The synthesis is illustrated by a representative group of simple monosubstituted guanidines shown in Table I.
Synthetic method for organic intermediate formamidine sulfinic acid
-
Paragraph 0023-0026, (2018/07/30)
The invention discloses a synthetic method for the organic intermediate formamidine sulfinic acid. The synthetic method comprises the following steps: adding 1-chloro-1-sulfo-diaminomethane and a potassium bromide solution into a reaction vessel, controlling a stirring speed to be 210-230 rpm, controlling a solution temperature to be 15-21 DEG C, adding a diethylene glycol diacetate solution and N-bromoacetamide and continuing a reaction for 90-120 min; and adding nickel nitrate powder, controlling a stirring speed to be 310-330 rpm, continuing a reaction for 2-4 h, lowering a temperature to 5-9 DEG C, then carrying out standing for 20-40 min, adding a sodium sulfate solution, subjecting the solution to layering to separate an oil layer, carrying out washing with a nitroethane solution for30-50 min, then carrying out recrystallization in a hexanediol solution, and carrying out dehydration with a dehydrating agent so as to obtain the finished formamidine sulfinic acid.
Efficient synthesis of 2-arylamino-2-imidazolines and 2-aminobenzimidazoles with aminoiminomethanesulfonic acid derivatives
Mohanazadeh, Farajollah,Nami, Navabe,Hosseini, Samine Sadat
experimental part, p. 1055 - 1058 (2012/01/04)
A highly efficient synthesis of 2-arylamino-2-imidazolines and 2-aminobenzimidazoles from aminoiminomethanesulfonic acid derivatives is described. The method is simple and practical, generating imidazoline and benzimidazoline derivatives in excellent isolated yields.
