25215-75-2Relevant articles and documents
Method for synthesizing hydrazine hydrate or carbodiimide at one step by using ammonia air oxidizing method
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Paragraph 0039; 0040; 0041, (2017/08/31)
The invention relates to a method for synthesizing hydrazine hydrate or carbodiimide at one step by using an ammonia air oxidizing method, and belongs to the technical field of chemical engineering processes. The method is characterized in that only ammonia and air are used as raw materials, and flow through a reactor which is filled with a solid catalyst, and gas and solid catalyzing reaction is performed, so as to synthesize the high-concentration hydrazine hydrate at one step; when methanol or formaldehyde is added into the raw materials, the carbodiimide is synthesized at one step. The method has the advantages that by fundamentally reforming the production of the two products, the production cost is greatly reduced, the production and environment-protection conditions are improved, and the product quality is improved.
Photochemistry of 1- and 2-Methyl-5-aminotetrazoles: Structural Effects on Reaction Pathways
Ismael,Fausto,Cristiano
, p. 11656 - 11663 (2016/12/09)
The influence of the position of the methyl substituent in 1- and 2-methyl-substituted 5-aminotetrazoles on the photochemistry of these molecules is evaluated. The two compounds were isolated in an argon matrix (15 K) and the matrix was subjected to in situ narrowband UV excitation at different wavelengths, which induce selectively photochemical transformations of different species (reactants and initially formed photoproducts). The progress of the reactions was followed by infrared spectroscopy, supported by quantum chemical calculations. It is shown that the photochemistries of the two isomers, 1-methyl-(1H)-tetrazole-5-amine (1a) and 2-methyl-(2H)-tetrazole-5-amine (1b), although resulting in a common intermediate diazirine 3, which undergoes subsequent photoconversion into 1-amino-3-methylcarbodiimide (H2N-N=C=N-CH3), show marked differences: formation of the amino cyanamide 4 (H2N-N(CH3)-C=N) is only observed from the photocleavage of the isomer 1a, whereas formation of the nitrile imine 2 (H2N-C-=N+=N-CH3) is only obtained from photolysis of 1b. The exclusive formation of nitrile imine from the isomer 1b points to the possibility that only the 2H-tetrazoles forms can give a direct access to nitrile imines, while observation of the amino cyanamide 4 represents a novel reaction pathway in the photochemistry of tetrazoles and seems to be characteristic of 1H-tetrazoles. The structural and vibrational characterization of both reactants and photoproducts has been undertaken.
Production of nanocatalyst from natural magnetite by glow discharge plasma for enhanced catalytic ozonation of an oxazine dye in aqueous solution
Taseidifar, Mojtaba,Khataee, Alireza,Vahid, Behrouz,Khorram, Sirous,Joo, Sang Woo
, p. 218 - 226 (2015/05/20)
Cheap natural magnetite (NM) was modified with oxygen plasma owing to its cleaning effect by chemical etching and with argon plasma due to its sputtering effect resulting in more surface roughness. These plasmas were utilized individually or in the order of first O2 and then Ar plasmas, respectively. The performance of the plasma treated magnetites (PTMs) was higher than NM for treatment of Basic Blue 3 (BB3) in catalytic ozonation (O3/PTM). The properties of NM and the most efficient treated magnetite (PTM4) samples were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Brunauer-Emmett-Teller (BET) and scanning electron microscopy (SEM) methods. The optimal values were chosen for operational parameters including ozone concentration (0.3 g/L), initial pH (6.7) and PTM4 dosage (600 mg/L). GC-Mass analysis was applied to detect intermediates. Environmentally-friendly treatment of the NM, simple separation of the catalyst, negligible leached iron concentration, successive reusability at milder pH and unaffected efficiency in the presence of inorganic salts are the main advantages of the PTM4.
Meteorites as catalysts for prebiotic chemistry
Saladino, Raffaele,Botta, Giorgia,Delfino, Michela,Di Mauro, Ernesto
, p. 16916 - 16922 (2014/01/06)
From outer space: Twelve meteorite specimens, representative of their major classes, catalyse the synthesis of nucleobases, carboxylic acids, aminoacids and low-molecular-weight compounds from formamide (see figure). Different chemical pathways are identified, the yields are high for a prebiotic process and the products come in rich and composite panels.
Synthesis and degradation of nucleic acid components by formamide and iron sulfur minerals
Saladino, Raffaele,Neri, Veronica,Crestini, Claudia,Costanzo, Giovanna,Graciotti, Michele,Di Mauro, Ernesto
experimental part, p. 15512 - 15518 (2009/03/12)
We describe the one-pot synthesis of a large panel of nucleic bases and related compounds from formamide in the presence of iron sulfur and iron-copper sulfur minerals as catalysts. The major products observed are purine, 1H-pyrimidinone, isocytosine, adenine, 2-aminopurine, carbodiimide, urea, and oxalic acid. Isocytosine and 2-aminopurine may recognize natural nucleobases by Watson-Crick and reverse Watson-Crick interactions, thus suggesting novel scenarios for the origin of primordial nucleic acids. Since the major problem in the origin of informational polymers is the instability of their precursors, we also investigate the effects of iron sulfur and iron-copper sulfur minerals on the stability of ribooligonucleotides in formamide and in water. All of the iron sulfur and iron-copper sulfur minerals stimulated degradation of RNA. The relevance of these findings with respect to the origin of informational polymers is discussed.
Kinetic study of chemical bath deposition of silver sulfide thin films
Meherzi Maghraoui, H.,Cowache,Lincot,Dachraoui
, p. 259 - 271 (2007/10/03)
The growth kinetics of silver sulfide films chemically deposited from aqueous silver nitrate-thiourea solutions at pH around 9 is studied as a function of the concentrations in solution, temperature (40 to 80°C) and hydrodynamic regime. It is found that the growth takes place in a narrow pH window (8.8 to 9.4). It is activated by temperature with an apparent activation energy of 20.4 kJ.mol-1, which is coherent with a diffusion control evidenced by experiments at different hydrodynamic regimes. The overall rate equation has been determined. The ultimate thickness of the films (around 1-2 microns) is actually limited by a parasitic process attributed to unsticking.
Investigation of the redox interaction between iron(III) 5,10,15,20-tetrakis(p-sulfonatophenyl)porphyrinate and aminoiminomethanesulfinic acid in aqueous solution
Lepentsiotis, Vasilios,Van Eldik, Rudi,Stulov, Dimitri M.,Makarov, Sergei V.
, p. 2915 - 2920 (2007/10/03)
Stability studies have been made on aminoiminomethanesulfinic acid [aimsa, thiourea dioxide, (NH2)2CSO2] and the reactions of aimsa and its decomposition product (dithionite, S2O42-) with iron(III) 5,10,15,20-tetrakis-(p-sulfonatophenyl)porphyrinate [FeIII(tpps)] in the presence of oxygen have been investigated. Application of NMR and stopped-flow spectrophotometry revealed direct evidence for the existence of two different forms of aimsa in aqueous solution. The slow formation of one of these forms, NH2NHCSO2H, is shown to determine the strong dependence of the reactivity of aimsa on the age of the stock solutions. Both aimsa and dithionite react in a similar way with FeIII(tpps) in alkaline solutions. The SO2?- radical plays a key role in the redox reactions. The ratio of the oxygen and radical concentration determines which kind of reaction (oxidation, reduction or decomposition) will dominate. In general a high oxygen concentration and a low radical concentration favour the oxidation and decomposition of the metalloporphyrin, whereas a high radical concentration and a low oxygen concentration favour the reduction. In strongly basic solutions ([NaOH] = 0.5 M) a redox cycle between FeIII(tpps) and FeII(tpps) is observed at low aimsa and dithionite concentration. Possible mechanisms for the decomposition of aimsa in alkaline solutions, as well as for the reactions between FeIII(tpps) and aimsa or dithionite, are proposed.
Photochemical fragmentation of unsubstituted tetrazole, 1,2,3-Triazole, and 1,2,4-triazole: First matrix-spectroscopic identification of nitrilimine HCNNH
Maier, Guenther,Eckwert, Juergen,Bothur, Axel,Reisenauer, Hans Peter,Schmidt, Christiane
, p. 1041 - 1053 (2007/10/03)
Equilibria between the tautomers of heterocyclic azoles like 1, 2, and 4 have been studied many times. We here show that the application of density functional methods in combination with matrix IR spectroscopy is a useful tool for determining which protomer is preferred in rare gas matrices and thus also can be assumed to dominate in the gas phase. Photolysis of tetrazole (4) in cryogenic matrices allows the IR-spectroscopic identification of a new CH2N2 isomer, the long sought-after nitrilimine HCNNH (6). Flash pyrolysis of 4 also yielded nitrilimine. Upon irradiation this species is converted to a second, previously unknown "isomer", an HCN/NH complex 13. Nitrilimine (6) can also be generated by photolyzing 1,2,3- (1) and 1,2,4-triazole (2) in Ar matrices. The complex photochemistry of all three heterocyclic precursor compounds was unveiled. Our findings were supported by isotopic substitution experiments and by high-level ab initio calculations. Moreover, the IR bands of iminocyanide HNCN were tentatively assigned. This radical has up to now not been observed in a matrix. VCH Verlagsgesellschaft mbH, 1996.
Infrared Spectrum of Matrix-Isolated Hexamethylenetetramine in Ar and H2O at Cryogenic Temperatures
Bernstein, Max P.,Sanford, Scott A.,Allamandola, Louis J.,Chang, Sherwood
, p. 12206 - 12210 (2007/10/02)
The infrared spectra of hexamethylenetetramine (HMT) isolated in an argon matrix at 12 K, frozen in H2O at temperatures from 12 to 200 K, and as a pure solid, are reported.The results of ultraviolet photolysis of matrix-isolated HMT and HMT frozen in H2O ice are also presented, and implications for infrared astronomy and astrochemistry are discussed.Furthermore, a simple technique for incorporating large nonvolatile organic molecules into a matrix is described.
Methoxy- and Aminoisocyanate
Teles, Joaquim Henrique,Maier, Guenther
, p. 745 - 748 (2007/10/02)
Methoxyisocyanate (1) can be prepared by photolysis of methyl azidoformate (3) or pyrolysis of N-methoxycarbonyl-O-methylhydroxylamine (4).Aminoisocyanate (2) is similarly formed on photolysis of carbamoyl azide (12) and pyrolysis of either methyl carbazate (13) or 3,4-diaminofurazan (14).The infrared spectra of 1 and 2 in an argon matrix at 10 K have been measured, and some of their properties are discussed. - Keywords: Flash pyrolysis/ Matrix IR spectroscopy/ Photolysis
