4076-36-2Relevant academic research and scientific papers
Combustion characteristics of EMOFs/oxygenated salts novel thermite for green energetic applications
Boffito, Daria C.,Chaouki, Jamal,Dubois, Charles,Fahd, Ahmed,Wen, John Z.,Zorainy, Mahmoud Y.
, (2021)
Metal-based thermites, especially those based on aluminum, have been recently included in materials for energetic applications such as pyrotechnics, propellants, and explosives. In parallel, several advances in the field of Metal-Organic Frameworks (MOFs) and Coordination Polymers (CPs) have as well paved the road for their use in developing novel energetic materials. In this context, we are introducing new thermites compositions with low ignition temperature, stable propulsive force, and high reactivity. These thermites are based on the [Cu4Na(Mtta)5(CH3CN)]n (Mtta = 5-Methyl-1H-tetrazole) energetic metal-organic framework (EMOF-1) as a fuel instead of pure metals. We first report the synthesis of an energetic MOF via the microwave-assisted technique as a more rapid and greener method. The efficiency of composites based on EMOF-1 and Al together with various oxygenated salts were investigated. Multiple instruments are involved to characterize the morphology and the structure of EMOF-1 and the developed systems, such as SEM-EDX, FTIR, and XRD. The combustion behavior of the novel composites was evaluated by TGA/DSC, bomb calorimetry and laser ignition. Additionally, the apparent kinetic parameters (activation energy & frequency factor) were calculated by the Kissinger and Ozawa approaches. The results revealed that the new thermite mixtures exhibit superior combustion characteristics of one and half to two-folds the average heat of combustion compared to aluminum-based ones, at almost half the ignition temperature. In this sense, the combustion reaction proceeds faster, easier (reduced activation energy), the ignition temperatures are noticeably lowered, and the heat released has considerably improved. In addition, they exhibited stable force with longer burning time. Among them, EMOF-1/KIO4 thermite exhibits the highest heat release (4.7 kJ/g), while EMOF-1/NH4NO3 thermite shows the lowest onset reaction temperature (224 ?C). EMOF-1/KClO4 yields the highest average force (8.4 N), calculated pressure (1365 kPa), pressurization rate (0.32 kPa/μs) and the longest burning time assigned to EMOF-1/K2S2O8 (40 ms).
Catalytic conversion of 2,4,5-trisubstituted imidazole and 5-substituted 1H-tetrazole derivatives using a new series of half-sandwich (η6-p-cymene)Ruthenium(II) complexes with thiophene-2-carboxylic acid hydrazone ligands
Vinoth, Govindasamy,Indira, Sekar,Bharathi, Madheswaran,Archana, Govindhasamy,Alves, Luis G.,Martins, Ana M.,Shanmuga Bharathi, Kuppannan
, (2020/11/16)
A new series of half-sandwich (η6-p-cymene) ruthenium(II) complexes with thiophene-2-carboxylic acid hydrazide derivatives [Ru(η6-p-cymene)(Cl)(L)] [L = N'-(naphthalen-1-ylmethylene)thiophene-2-carbohydrazide (L1), N'-(anthracen-9-ylmethylene)thiophene-2-carbohydrazide (L2) and N'-(pyren-1-ylmethylene)thiophene-2-carbohydrazide (L3)] were synthesized. The ligand precursors and their Ru(II) complexes (1–3) were structurally characterized by spectral (IR, UV–Vis, NMR and mass spectrometry) and elemental analysis. The molecular structures of the ruthenium(II) complexes 1–3 were determined by single-crystal X-ray diffraction. All complexes were used as catalysts for the one-pot three-component syntheses of 2,4,5-trisubstitued imidazole and 5-substituted 1H-tetrazole derivatives. The catalytic studies optimized parameters as solvent, temperature and catalyst. The catalysts revealed very active for a broad range of aromatic aldehydes presenting either electron attractor or electron donor substituents and, although less active, moderate to high activities were observed for alkyl aldehydes.
Synthesis, structural and computational studies of new tetrazole derivatives
Klisuri?, Olivera R.,Oklje?a, Aleksandar M.
, (2020/10/08)
Herein, we report a synthesis of two new disubstituted tetrazoles, 2-(2,4-dinitrophenyl)-5-methyl-2H-tetrazole (2) and 1-(2,4-dinitrophenyl)-5-methyl-1H-tetrazole (3). The products were characterized by 1H and 13C NMR spectroscopy, as well as single-crystal X-ray diffraction. The intermolecular interactions in the crystals were investigated by Hirshfeld surface analysis, 2D fingerprint plots, and noncovalent interaction analysis (NCI). Tetrazole rings of both compounds were found to be involved in both strongest attractive and repulsive intermolecular interactions. DFT calculations were performed using the PW6B95-D3(BJ)/def2-TZVP level of theory in order to obtain information about the molecular electrostatic potential (MEP), and global and local reactivity (dual descriptor) indices of the studied tetrazoles. The calculated molecular electrostatic potentials correlated well with the Hirshfeld surface and NCI plots. The 1,5-disubstituted tetrazole exhibited lower kinetic stability and was slightly more electrophilic than the 2,5-regioisomer. The dual descriptor index was used to reveal electrophilic and nucleophilic sites for both molecules.
Igneous rock powder as a heterogeneous multi-oxide nano-catalyst for the synthesis of 5-substituted-1H-tetrazoles in polyethylene glycol
Javaherian, Mohammad,Movaheditabar, Parviz,Nobakht, Valiollah
, (2021/10/25)
The use of igneous rock nano-powder as a heterogeneous and recyclable multi-oxide nano-catalyst synthesizing of 5-substituted-1H-tetrazoles is reported. The igneous rock nano-powder was initially prepared by using the ball-milling method. Then, the structure, morphology, and magnetic properties of the prepared igneous rock nano-powder were characterized with some different spectroscopic, microscopic, and thermogravimetric techniques, such as FTIR, FESEM, XRF, XRD, Histogram, and EDS. The instrumental analyses showed that the prepared igneous rock powder is a mixture of metal oxides, such as Si, Al, Ca, Mg, Fe, Na, Mn, and Sr. It showed an excellent catalytic performance in synthesizing of 5-substituted-1H-tetrazoles through [3 + 2] cycloaddition reaction between sodium azide and nitrile compounds. Various aliphatic and aromatic nitriles and sodium azide were reacted in the presence of a catalytic amount of igneous rock nano-powder at 80 o C temperature in PEG-400. The protocol was simple and rapid, with suitable yields of the obtained tetrazoles. The igneous rock nano-powder is readily accessible, reusable, and holds potential for further application in acid-catalyzed organic syntheses and industrial requirements. Graphic abstract: [Figure not available: see fulltext.]
TMSN3-Bu2Sn(OAc)2: A modified and mild reagent system for Wittenberger tetrazole-synthesis
Yoneyama, Hiroki,Oka, Naoki,Usami, Yoshihide,Harusawa, Shinya
, (2020/01/21)
Treatments of various nitriles with TMSN3 and Bu2Sn(OAc)2 at 30 °C in benzene for 60 h yielded the corresponding 5-substituted 1H-tetrazoles in good to excellent yields. This method is a mild and efficient alternative reagent system for Wittenberger tetrazole-synthesis that uses TMSN3 and Bu2SnO in toluene at high temperature (93–110 °C) for 24–72 h.
A 5 - substituted four nitrogen azole compound of synthetic method (by machine translation)
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Paragraph 0016; 0017; 0018, (2019/04/04)
The invention discloses a 5 - substituted four nitrogen azole compound of synthetic method, the synthesis method of the process is as follows: to point pen in the autoclave (I) indicated by the nitrile compounds, sodium azide, nickel ferrite and carboxylic acid ammonium ion exchange resin, added with an organic solvent to the cyclization reaction, the reaction solution after the reaction is finished filter, pickling, desolvation and heavy after crystallization, as shown in formula (II) of the 5 - substituted tetrazole compounds, yield is 85 - 95%, purity ≥ 99%; Formula (I) in the formula (II), the substituent R1 Is phenyl, substituted phenyl, C1 - C3 alkyl or amino; substituted phenyl substituent is methyl, methoxy, F or nitro. The invention of 5 - substituted tetrazole compounds synthesis method, adopt the catalytic ferrous acid nickel and carboxylic acid ammonium ion exchange resin catalyst combination, the carboxylic acid [...], not only good general the reaction substrate, the reaction yield is high, and the catalyst is easily separated and recycled, the production cost is reduced and the three waste emissions. (by machine translation)
Batch Versus Flow Lithiation–Substitution of 1,3,4-Oxadiazoles: Exploitation of Unstable Intermediates Using Flow Chemistry
Wong, Jeff Y. F.,Tobin, John M.,Vilela, Filipe,Barker, Graeme
supporting information, p. 12439 - 12445 (2019/09/06)
1,3,4-Oxadiazoles are a common motif in pharmaceutical chemistry, but few convenient methods for their modification exist. A fast, convenient, high yielding and general α-substitution of 1,3,4-oxadiazoles has been developed using a metalation-electrophilic trapping protocol both in batch and under continuous flow conditions in contradiction to previous reports which suggest that α-metalation of this ring system results in ring fragmentation. In batch, lithiation is accomplished at an industrially convenient temperature, ?30 °C, with subsequent trapping giving isolated yields of up to 91 %. Under continuous flow conditions, metalation is carried out at room temperature, and subsequent in flow electrophilic trapping gave up to quantitative isolated yields. Notably, lithiation in batch at room temperature results only in ring fragmentation and we propose that the superior mixing in flow allows interception and exploitation of an unstable intermediate before decomposition can occur.
Application of Photoclick Chemistry for the Synthesis of Pyrazoles via 1,3-Dipolar Cycloaddition between Alkynes and Nitrilimines Generated In Situ
Remy, Richard,Bochet, Christian G.
, p. 316 - 328 (2018/01/27)
The photochemical extrusion of gaseous nitrogen from 2,5-disubstituted tetrazoles to generate reactive nitrilimines in situ represents an efficient and attractive way to form dipoles that can be used to provide useful chemicals via 1,3-dipolar cycloadditions. The concept of “photoclick chemistry” already inspired numerous researchers, who exploited photochemical processes involving alkenes for the synthesis of adducts or the functionalization of biocompatible materials. The approach requires bioorthogonality, ease of access to the starting materials and operational simplicity. We report herein our investigations toward a photoclick reaction involving 2,5-disubstituted tetrazoles and alkynes as the dipolarophile for the synthesis of pyrazole derivatives. In addition to the numerous reports recently published on the synthesis of pyrazoles, we wish to add to the list a photochemical procedure that represents a mild and atom-economical alternative. Moreover, considering that such nitrilimines precursors can be accessed in one step from inexpensive and abundant starting materials and given the commercial availability of a broad spectrum of alkynes, we examined the scope of the photoclick reaction with respect to reactive partners, enabling the synthesis of a library of useful heteroaromatics.
[3 + 2] Cycloaddition promoted by zinc oxide nanoparticles anchored on reduced graphene oxide using green solvent
Clarina, Thanaraj,Rama, Velladurai
supporting information, p. 175 - 187 (2018/01/01)
ZnO anchored on RGO-catalyzed [3 + 2] cycloaddition of nitriles and sodium azide in the synthesis of 5-substituted 1H-tetrazoles in water is an efficient and simple protocol with low catalyst loading under reflux condition. It is applied to a wide range of substrates with an excellent yield, simple workup procedure, recovery, and reusability of catalyst with consistent activity and high turnover number. It is proposed that the functional groups present in RGO surface are effective for preventing the aggregation of catalytically active ZnO species during the reaction. Moreover, the excellent performance of ZnO–RGO nanocomposite is ascribed to the excellent dispersity of catalyst in water, hydrophilic nature of the RGO for the accumulation of organic substrates in water, and the “Breslow effect.”.
A zinc Lewis acid surface active agent for the preparation of 5' - substituted tetrazole compounds
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Paragraph 0136-0144, (2018/09/08)
The invention belongs to the field of organic synthetic technology, and specifically relates to a zinc Lewis acid surfactant as catalysts for preparing the 5' - substituted compound four azole class method. The method comprises the following steps: 1) to zinc Lewis acid surfactant Zn (OSO2 Cn H2 N + 1 )2 As the catalyst, R cyanide and sodium azide in water reaction to obtain the 5' - R base four nitrogen zuo compound of zinc salt and by-product NaOSO2 Cn H2 N + 1 ; 2) In the step 1) of the obtained 5 '- R base four nitrogen zuo compound of zinc salt in the acidification is carried out under acidic conditions, to obtain the 5' - R base four nitrogen zuo compounds and by-product zinc bromide; 3) by-product NaOSO2 Cn H2 N + 1 And by-product zinc bromide in the substitution reaction under acidic conditions, to obtain zinc Lewis acid surfactant Zn (OSO2 Cn H2 N + 1 )2 . Method can be used in "one-pot" strategy, the starting material by continuous cyclization reaction, the acidification reaction directly preparation containing the tetrazole compound of the structural unit; the method used in the zinc Lewis acid surfactant can be recovered after the reaction.
