Degradation of 3,5‐dimethyl‐tetrahydro‐2H‐1,3,5‐thiadiazine‐2‐thione in aqueous aerobic media

Abstract

Abstract-Decomposition of 3,5-dimethyl-tetrahydro-2H-1,3,5-thiadiazine-2-thione (DTTT) has been studied by UV-visible spectroscopy (UV-VIS), high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and fast atom bombardment-mass spectrometry (FAB-MS). Hydrolysis rate constants for DTTT and rate constants for product formation were measured. The partially hydrolyzed and aged DTTT solutions have been separated and analyzed by GC-MS. Formaldehyde, 1,3-dimethyl-2-thiourea, N-methyl dithiocarbamic methyl ester, N-methyldithiocarbamic perthiomethyl ester, 2-methyl-5-dihydro-3H-4-thia-1,2-isooxazolidine-3-thione, 1,3,5-trimethyl-hexahydro-2H-1,3,5-triazine-2-thione, 4-methyl-5-methylimino-1,2,4-dithiazolidine-3-thione, and 2,4-dimethyl-1,2,4-thiadiazolidine-3,5-dithione were identified from the hydrolyzed DTTT solution. Methyl isothiocyanate, which is one of the intermediates formed during the decomposition of DTTT, was also monitored by UV-VIS and HPLC for the formation of common products and characterized by GC-MS. The decomposition pathways for DTTT are presented and are in accord with the limited literature data. Environmental impact assessment of the DTTT and its metabolites is summarized.

Study on the Decomposition Products of Thiadiazinthione and their Anticancer Properties

“…The major compund (Ϸ 68 %) showed in its UV spectrum bands at 245 (sh) and 221 nm and a molecular weight of 236. The band at 245 nm was originated from C=S chromophore [16]. This compound was identified as N,N'-difurfurylthiourea (5) as previously reported [17].…”

“…Some papers on the decomposition products of tetrahydro-2H-1,3,5-thiadiazin-2-thione derivatives were reported. The presence of dithiocarbamate esters and isothiocynates [13], N,N'-disubstituted-thioureas, amines and 3,5-disubstituted-2H-1,3,5-thiadiazin-2-thiones [14], the product corresponding to the hydrolysis of C 4 -N 5 bond of thetrahydro-thiadiazinthione ring [15] and other six and five-membered heterocycles [16], were described as decomposition products. In order to clarify this point, a study using reverse high-performance liquid chromatography and mass spectrometries (HPLC-MS) was carried out.…”

Degradation of Dazomet by Thermal Fenton and Photo-Fenton Processes under UV and Sun lights at Different Temperatures

“…It has been found that the highest degradation of aqueous solution of Dazomet has been obtained from solar photo-Fenton reaction as shown in Table 3. The reasons for these results were explained from the mechanism described early by the equations (1)(2)(3)(4)(5). Irradiation of the Fenton reaction not only regenerates Fe +2 , the crucial catalytic species in the Fenton reaction, but also produces an additional hydroxyl radical, the species responsible for the degradation of organic material.…”

“…Dazomet (tetrahydro-3,5-dimethyl-1,3,5thiadiazine-2-tione ) (IUPAC) is a soil fumigant . It is also known as tetrahydro-3,5-dimethyl-2H-1,3,5thiadiazine-2-thione (1) Many researchers have studied the properties of Dazomet and its degradation in various methods such as UV-visible spectroscopy, high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), and fast atom bombardment-mass spectrometry (FAB-MS) (2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). In this work Dazomet pesticide has been used to study its degradation using Fenton processes (13).…”