13036-89-0Relevant articles and documents
Compound heavy metal chelating agent containing dithiocarboxylate functionalized ethoxylated pentaerythritol core hyperbranched polymer
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Paragraph 0033-0035, (2020/12/13)
A compound heavy metal chelating agent, which relates to the field of chemical and environmental protection technology, includes dithiocarboxylate functionalized ethoxylated pentaerythritol core hyperbranched polymer and alkylene diamine-N,N′-sodium bisdithiocarboxylate with a molar ratio in a range of 1:1.0 to 1:10.0. The two different structural types of components have the synergistic positive effect. While chelating heavy metals, the compound heavy metal chelating agent alternately combine with heavy metals to form insoluble chelating super-molecular deposits, which has both chelation and flocculation functions. The compound heavy metal chelating agent provided by the present invention is able to reach the standard for treating heavy metal wastewater, and especially low concentration heavy metal wastewater. It has a wide adaptability range, and does not need to add coagulant. Moreover, it is simple in preparation method, easily available for raw materials, low in cost, and easy to be industrialized.
Mechanisms of acid decomposition of dithiocarbamates. 2. Efficiency of the intramolecular general acid catalysis
Humeres, Eduardo,Debacher, Nito A.,Sierra, M. Marta De S.
, p. 1807 - 1813 (2007/10/03)
The acid decomposition of ethylenebis(dithiocarbamate) (EbisDTC) and glycinedithiocarboxylate (glyDTC) was studied in water at 25 °C in the range of rio -5 to pH 5. The acid dissociation constants of all species involved were calculated from LFER and from the pH-rate profiles. According to the pK(a) of the parent amine of the reactive species, both compounds decompose through the dithiocarbamate anion and a zwitterion intermediate. The intermolecular N-protonation rate constant of the carboxylic conjugate acid of glyDTC anion is 12.6 M-1 s-1, slower than the C-N breakdown. This species also cleaves through an intramolecular general acid-catalyzed mechanism where the rate constant for the N-protonation is (7.1 ± 4.2) x 103 s-1 and the efficiency of the proton-transfer step as measured by the effective molarity is (5.6 ± 3.3) x 102 M. The acid decomposition of the dithiocarbamic conjugate acid of EbisDTC anion proceeds through a fast N- protonation and a slower C-N breakdown. The intramolecular general acid catalysis rate constant is (8.2 ± 2.8) x 106 s-1, but the efficiency of this fast proton transfer is only (14.3 ± 4.9) M. The intramolecular general acid catalysis of the free acid forms of the carboxylic and dithiocarbamic groups is unfavorable for about 4 kcal mol-1 with respect to the protonation of the external hydron, and consequently, no external buffer catalysis is expected to be observed for dithiocarbamates that decompose through a zwitterion intermediate. The difference between the pK(b) of the proton acceptor and the pK(a) of the donor follows the order of the proton efficiency. Estimation of the strength of the hydrogen bonding in the reagent and product supports the assumption that a thermodynamically favorable change of hydrogen bonding from reagent to product increases the efficiency of proton transfer.
Fungicidal compositions employing synergistic mixtures of phenylacetamide derivatives and Zineb or Mancozeb
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, (2008/06/13)
Synergistic mixtures of fungicidal N-(2,6-dimethyl-phenyl)-N-(1-methoxycarbonyl-ethyl)-phenylacetamide with other selected fungicides which are ethylene-bis-dithiocarbamates, N-trichloromethylthio-imides or copper oxychloride are disclosed as are compositions comprising the synergistic mixtures. Said mixtures and compositions are effective in controlling fungi infections of useful plants.
