Elimination Of Molecular Nitrogen Research Articles

Chemical looping ammonia synthesis at atmospheric pressure benefiting from synergistic effect of Mn- and Fe-based nitrogen carriers

Chemical looping ammonia synthesis (CLAS) based on the synergistic effect of Mn- and Fe-based nitrogen carriers, is proposed as an environmental-friendly NH3 production alternative. This approach has superiority of intermittent and simplified operation, especially in locations where implementing sophisticated Haber-Bosch process is challenging. This work revealed that nitrogen carriers could yield up to 166.3 μmol NH3 per gram of Mn after conversion with H2 at 600 °C. NH3 production capacity was deteriorated by sintering and ammonia decomposition at high temperature. Pores resulting from the elimination of molecular nitrogen by bursting out of the surface were found at 700 °C, which could be explained by the parasitic conversion of N to N2 rather than NH3. N-carrier with 50% Al2O3 was the most interesting candidate with outstanding conversion ratio of lattice nitrogen. Generally, simple design, operational security and low cost make CLAS possible to scale up for industrial usage in the future.

Photoredox-catalyzed synthesis of N-unsubstituted enaminosulfones from vinyl azides and sulfinates

A metal-free visible light photoredox-catalyzed synthesis of N-unsubstituted enaminosulfones from vinyl azides and sodium sulfinates in moderate to high yields is described. The reaction proceeds in ethanol and uses eosin Y as a readily available photocatalyst in combination with nitrobenzene as an electron shuttle. Taking into account the number of steps involved (generation of the sulfonyl radical, its addition to the double bond, elimination of molecular nitrogen with formation of an iminyl radical, followed by its reduction and protonation) as well as the number of redox-active reaction partners involved, the selectivity of the process is quite impressive.

Influence of the Mechanism of the Initial Stages of the Ligand Decomposition on the Initiating Ability of Cobalt(III) Ammine Tetrazolate Complexes

The results of quantum chemical calculations for isolated molecules of pentaammine-(5-cyano-2H-tetrazolato-N2)cobalt(III) perchlorate, pentaammine-(5-nitrotetrazolato-N2)cobalt(III) perchlorate, tetraammine-cis-bis(5-nitro-2H-tetrazolato-N2)cobalt(III) perchlorate, and tetraammine-cis-bis(1-methyl-5-aminotetrazolo-N3,N4)cobalt(III) perchlorate, as well as of the products of their possible initial decomposition stage were presented. The energetics and pathways of such reactions were determined. For the first time with the use of quantum chemical calculations it was shown that the decomposition of cobalt amminates can start with destruction of the tetrazole ligand and elimination of molecular nitrogen, rather than with dissociation of the coordinated ammonia molecule from the inner sphere of the cobalt(III) complex. The activation and dissociation energies of these processes were determined.

Free Radical Synthetic Protocol for Benzothiazoles via Ring Opening of Benzotriazole: A Two‐step Organic Chemistry Experiment for Undergraduate and Postgraduate Students

The utility and advantages of benzotriazole methodology have been described for the practical synthesis of benzothiazoles. The two‐step synthetic procedure includes nucleophilic acyl substitution followed by benzotriazole ring cleavage under the free radical condition and subsequent cyclization via elimination of molecular nitrogen (N2). This protocol requires cheap and readily available reagents, and moreover easy to handle, thus can be used to teach undergraduate and postgraduate students about the importance of benzotriazole moiety in organic synthesis, ring cleavage chemistry, cyclization reactions, and use of industrial waste in free radical reactions. Students can also learn some important and common techniques useful in organic chemistry such as monitoring of organic reaction using thin‐layer chromatography and UV, microwave (MW) technique for the synthesis, and column chromatography for the product isolation and structure determination through NMR, MS, and IR spectral analysis of the pure compounds.

N‐Imidazolylation of Sulfoximines from N‐Cyano Sulfoximines, 1‐Alkynes, and N‐Sulfonyl Azides

AbstractThe rhodium‐catalyzed N‐imidazolylation of N‐sulfonyl‐1,2,3‐triazoles with a variety of N‐cyano sulfoximines has been developed for the synthesis of N‐imidazolyl sulfoximines via elimination of molecular nitrogen. Copper‐catalyzed [3+2] cycloaddition followed by rhodium‐catalyzed N‐imidazolylation from 1‐alkynes, N‐sulfonyl azides, and N‐cyano sulfoximines is also demonstrated for the synthesis of N‐imidazolyl sulfoximines in a one‐pot procedure.magnified image

Synthesis of 3,3-diphenyl-3H-pyrazoles applying vinyl sulfones as chemical equivalents of acetylenes in reaction of 1,3-dipolar cycloaddition to diphenyldiazomethane

Vinyl phenyl sulfone, methyl (E)-3-(phenylsulfonyl)- and methyl (E)-3-(p-tosyl)acrylates, (E)-3-(phenylsulfonyl)- and (E)-3-(p-tosyl)acrylonitriles react in ethyl ether at 20°C with diphenyldiazomethane leading to the formation of the corresponding 5,5-diphenyl-3-(arylsulfonyl)- Δ2-pyrazolines. Products containing a methoxycarbonyl or cyano group at treating with DBU in dichloromethane at 0°C suffer a dehydrosulfonation and are converted into 4-substituted 3,3-diphenyl-3H-pyrazoles. The oxidation of the mentioned Δ2-pyrazolines with activated manganese dioxide in benzene at 20°C leads to the formation of 4-methoxycarbonyl- and 4-cyano-substituted 5-arylsulfonyl- 3,3-diphenyl-3H-pyrazoles respectively. The reactions of α-bromovinyl phenyl sulfones and a-bromovinyl methyl sulfones with diphenyldiazomethane afforded the corresponding 3-bromo- 5,5-diphenyl-3-sulfonyl-Δ1-pyrazolines. The first among them at 20°C suffered spontaneous elimination of molecular nitrogen and converted into 1-bromo-2,2-diphenyl-1-(phenylsulfonyl)cyclopropane whose structure was established by X-ray diffraction analysis. The action of DBU on another Δ1-pyrazoline resulted in the formation of the product of the Ramberg–Backlund reaction, 5-methylene-3,3-diphenyl-Δ1- pyrazoline together with the product of hydrodebromination–isomerization, 5,5-diphenyl-3-(methylsulfonyl)- Δ2-pyrazoline.

1,3-Dipolar addition of diazocyclopropane to eudesmane-type methylidene lactones and thermolysis of the resulting spiro-fused pyrazolines

Reactions of alanto-, isoalanto-, and alloalantolactones, which are unsaturated eudesmane-type lactones, with diazocyclopropane generated in situ from N-cyclopropyl-N-nitrosourea under the action of sodium methoxide proceed alike, are highly regio- and stereoselective, and always give spiro-fused pyrazolines via cycloaddition to the exocyclic double bond of the methylidene group of the lactone ring. Their thermolysis at 195–210 °C results in elimination of molecular nitrogen, mainly yielding spiropentane-containing lactones. Minor thermolysis products (10–12%) are isomeric 13-cyclopropyl lactones.

Reactions of 4-phenyl-1,2,4-triazoline-3,5-dione with 2-pyrazolines

4-Phenyl-1,2,4-triazoline-3,5-dione (PTAD) acts as an efficient Michael acceptor in reactions with 1-unsubstituted 2-pyrazolines, giving substituted (3,5-dioxo-4-phenyl-1,2,4-triazol-idin-1-yl)-1-pyrazolines in quantitative yields. Through elimination of molecular nitrogen, the latter are easily transformed into the corresponding cyclopropanes. A reaction of methyl 5-methyl-2-pyrazoline-5-carboxylate with a twofold excess of PTAD leads to an intermediate bisadduct, which undergoes dediazotization to form a 1,3,5-triazabicyclo[3.3.0]octane-2,4-dione derivative. 1-Substituted 2-pyrazolines also add to PTAD with the exception that the 2-pyrazoline structure is retained in the product because of the migration of the C(3)H proton to PTAD.

Chemical transformations of 3-aminopyrrolidin-2-ones of the norbornane and cyclopropane series

3-Aminopyrrolidin-2-ones containing a fused norbornane or spirocyclopropane fragment react with benzaldehyde to give azomethines, which can be transformed into N-substituted 3-aminopyrrolidin-2-ones by reduction with sodium borohydride. Diazotization of amino-pyrrolidinones with NaNO2 in acetic acid results in the elimination of molecular nitrogen and in the formation of acetoxy or unsaturated derivatives (through stabilization of intermediate carbocations). 6-Methylidene4-azaspiro[2.4]heptan-5-one obtained by diazotization of 6-amino-6-methyl-4-azaspiro[2.4]heptan-5-one easily reacts with diazomethane, diazocyclo-propane, and benzonitrile oxide to yield heterocyclic spiranes by means of 1,3-dipolar cycloaddition.

Reactions of Transition Metal Azido Complexes and their Reaction Products

AbstractTransition metal azido complexes can undergo various reactions of their azido group to yield interesting products. The cleavage of the Naα‐Nβ bond and elimination of molecular nitrogen can generate nitrido complexes like MoNCl3 or WNCl3, chloroiminato complexes like Cl3VNCl, or phosphoraneiminato complexes like [Cl4NbNPPh3]2 with metal nitrogen multiple bonds. The reductive elimination of the complete azido group on the other hand may produce metal(0) fragments which in case of gold(I) azido complexes can combine to form clusters.

Theoretical Investigation of the Gas‐Phase Decomposition of Ga(N3)2Et as a Model for a Single‐Molecule GaN Precursor

AbstractDensity functional theory‐type calculations have been used to investigate possible decomposition pathways of the gallium azide Ga(N3)2Et, which served as a model for the working single‐molecule precursor Ga(N3)2[(CH2)3NMe2] (BAZIGA). Both kinetics and thermodynamics of radical and non‐radical reactions have been considered, focusing especially on the entropic effects at elevated temperatures. The β‐hydrogen elimination was found to be kinetically favored over the elimination of molecular nitrogen from the azide ligands. However, due to the strong entropic contributions that are able to compensate for bond energies, homolytic bond cleavage was calculated to be more facile than any non‐radical rearrangement reaction. A two‐step radical decomposition mechanism leading to the monoazide GaN3 (consistent with the available experimental results) is proposed.

THE EFFECT OF TRIETHANOLAMINE ON THERMAL DECOMPOSITION OF GAP

ABSTRACT The effect of triethanolamine (TEA) on thermal behavior of glycidyl azide polymer (GAP) has been investigated by direct pyrolysis mass spectrometry technique. It has been observed that thermal degradation of GAP-TEA mixture also begins with the cleavage of the side groups as in the case of GAP. Again, the main decomposition started with the elimination of molecular nitrogen from the azide functional group, and a quite similar degradation mechanism has been proposed. The increase in the thermal stability of GAP in the presence of TEA was attributed to formation of a crosslinked structure. The heating rate had little impact on the relative abundances of the degradation products of the GAP-TEA mixture contrary to what has been observed for GAP. Thus, it may be proposed that the effect of heating rate on thermal degradation behavior of a crosslinked polymer is negligible.

Thermal decomposition of glycidyl azide polymer by direct insertion probe mass spectrometry

Thermal decomposition reactions and products of glycidyl azide polymer (GAP), have been investigated by direct insertion mass spectrometry and evolved gas analyses by FTIR spectroscopy techniques. It has been observed that thermal degradation of GAP begins with cleavage of the side groups. Although the main decomposition started with the elimination of molecular nitrogen from the azide functional group, degradation initiated by loss of N 3 and CH 2N 3, depolymerization type reactions were also identified. Rearrangement reactions and/or H 2 evolution after the initiation step resulted in various polymeric structures that decompose subsequently. Furthermore, loss of low molecular weight, stable species such as CH 3N 3 and HN 3 directly from GAP and H 2CNH, and HCN from polymeric imine produced by the rearrangement reactions following elimination of N 2 from GAP have shown to be effective. Evolved gas analyses by FTIR spectroscopy confirmed formation of small molecular weight species such as CO, CH 4, C 2H 2, CH 2CO, and NH 3.

The reaction of 2-(tetrazol-5-yl)alkyl ketones and of 2-(tetrazol-5-yl)alkanoic acid derivatives with lead tetraacetate. A novel method of preparation of alk-2-ynyl ketones and alk-2-ynoic acid derivatives †

The majority of tetrazolylacetyl derivatives 2 and 7, when treated with lead tetraacetate in dry 1,4-dioxane at room or lower temperature, are oxidized with elimination of molecular nitrogen mainly to the corresponding alkynoyl derivatives 4 and 8, respectively. Vinylidenes (25) have been shown to be the intermediates of the reaction. The reaction does not take place when either the tetrazolyl group is N-substituted or the carbon atom separating the tetrazolyl and the carbonyl groups is disubstituted or these two groups are separated by two carbon atoms as in compound 17. The reaction offers a convenient method for the conversion of 2-cyanoacetyl derivatives into alk-2-ynoyl derivatives via intermediate tetrazolylacetyl derivatives. The 4-methoxyanilide 7o reacts differently, affording the fused heterocyclic compounds 19o and 20o.

A New Synthetic Route to 1-Halogeno-1-cyclopropanecarboxylates

Substituted bicyclic 1-halogeno-1-cyclopropanecarboxylates have been prepared by elimination of molecular nitrogen from 4-halogeno-7-aryl-1-methyl-2,3,7-triazabicyclo[3.3.0]oct-2-en-4-carboxylates, which were obtained by the reaction of 7-aryl-1-methyl-2,3,7-triazabicyclo[3.3.0]oct-3-encarboxylates with halogens (Cl2, Br2).

Laser Photodissociation and Thermal Pyrolysis of Energetic Polymers

Decomposition reactions of glycidyl azide polymer (GAP) and poly(glycidyl nitrate) (PGN) have been investigated by pulsed infrared laser pyrolysis and ultraviolet laser photolysis of thin films at 17−77 K. Reactions are monitored by transmission FTIR spectroscopy. Photolysis of GAP at 266 nm shows that the initial reaction steps are elimination of molecular nitrogen with subsequent formation of imines. Warming leads to loss of the imines, most likely as a result of secondary polymerization reactions. Thermal decomposition of GAP by infrared laser pyrolysis reveals products similar to the UV experiments after warming. Laser pyrolysis of PGN indicated that the main steps of decomposition are elimination of NO2 and CH2O from the nitrate ester functional group, followed by rearrangement of the polymer backbone to form carbonyl functional groups. Higher order reactions form numerous small molecule products including NO, CO, CO2, N2O, H2O, HNCO, HCN, HCNO, HONO, and CH4. UV laser photolysis of PGN shows the maj...

Detonation Chemistry Of Glycidyl Azide Polymer

AbstractThe initial step of chemical reaction initiated by laser-generated shock waves has been observed in glycidyl azide polymer (GAP) in condensed phase. Shocks are generated by pulsed laser vaporization of thin aluminum films and launched into adjacent films of GAP at 77 K. Comparison of FIIR spectra obtained before and after shock passage shows that initial reaction involves elimination of molecular nitrogen from the azide functional groups of the polymer. The shock arrival time has been measured by a velocity interferometer as a function of thickness of GAP and laser fluence. The shock pressure has been calculated by using a universal liquid state Hugoniot. A simple model is proposed to calculate shock velocity and pressure as a function of laser fluence. The results are in agreement with experimental data.

ChemInform Abstract: Formation of α‐Enamino Ketones from α‐Azido Ketones: An Elimination of Molecular Nitrogen from α‐Azido Ketones.

ChemInformVolume 19, Issue 20 Preparative Organic Chemistry ChemInform Abstract: Formation of α-Enamino Ketones from α-Azido Ketones: An Elimination of Molecular Nitrogen from α-Azido Ketones. K. VAN SANT, K. VAN SANT Monsanto Agric. Co., St. Louis, MO 63167, USASearch for more papers by this authorM. S. SOUTH, M. S. SOUTH Monsanto Agric. Co., St. Louis, MO 63167, USASearch for more papers by this author K. VAN SANT, K. VAN SANT Monsanto Agric. Co., St. Louis, MO 63167, USASearch for more papers by this authorM. S. SOUTH, M. S. SOUTH Monsanto Agric. Co., St. Louis, MO 63167, USASearch for more papers by this author First published: May 17, 1988 https://doi.org/10.1002/chin.198820093Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume19, Issue20May 17, 1988 RelatedInformation

Formation of α-enaminoketones from α-azidoketones: An elimination of molecular nitrogen from α-azidoketones

α-Enaminoketones are readily accessible through reaction of α-bromoketones with sodium azide followed by an elimination of molecular nitrogen. The reaction is base catalyzed and proceeds under relatively mild conditions. An anionic mechanism is proposed.