scholarly journals PROPELLANS – PERSPECTIVE FRAME COMPOUNDS FOR THE CREATION OF HIGH-ENERGY SUBSTANCES

2021 ◽  
pp. 144-148
Author(s):  
А.А. Минакова ◽  
С.Г. Ильясов
Keyword(s):  
Gradual Increase ◽  
Theoretical Calculations ◽  
High Energy ◽  
Biologically Active ◽  
Reaction Products ◽  
Energy Characteristics ◽  
Alkyl Derivatives ◽  
Nitro Derivatives ◽  
Selective Formation ◽  
Competing Reactions

Важной задачей современной органической химии является открытие новых, ранее не известных науке веществ, которые могли бы расширить область наших знаний и пополнить номенклатуру высокоэнергетических или биологически активных продуктов. 3,7,10-Триоксо-2,4,6,8,9,11-гексааза[3.3.3|пропеллан и его нитропроизводные являются новейшими продуктами класса гетероциклов, их азотсодержащая полициклическая структура предполагает наличие интересных и полезных свойств, что обусловливает проявленный интерес к данной работе. Химия 3,7,10-триоксо-2,4,6,8,9,11-гексааза[3.3.3|пропеллана малоизучена и представлена лишь двумя алкилпроизводными и теоретическими расчетами энергетических характеристик нитропроизводных. В статье преставлены результаты исследования нитрования 3,7,10-триоксо-2,4,6,8,9,11-гексааза[3.3.3]пропеллана (THAP) концентрированнойазотной кислотой. Установлено, что в процессе нитрования наблюдается протекание двух конкурирующих реакций – лактам-лактимной перегруппировки и нитрования. Было показано, что продукты реакции сильно зависят от температуры реакционной массы. Установлено, что температуре -40 ºС протекает образование лактимной формы ТНАР, тогда как при постепенном увеличении температуры сначала образуется мононитропроизводное пропеллана, а при температуре 40 ºС идёт селективное образование 3,7,10-триоксо-2,6-динитро-2,4,6,8,9,11-гексааза[3.3.3]пропеллана с выходом 30%. An important task of modern organic chemistry is the discovery of new substances previously unknown to science, which could expand the area of our knowledge and replenish the range of high-energy or biologically active products. 3,7,10-Trioxo-2,4,6,8,9,11-hexaaza[3.3.3]propellane and its nitro derivatives are the newest products of the class of heterocycles; interest in this work. The chemistry of 3,7,10-trioxo-2,4,6,8,9,11-hexaaza[3.3.3]propellane is poorly understood and is represented by only two alkyl derivatives and theoretical calculations of the energy characteristics of nitro derivatives. The article presents the results of a study of the nitration of 3,7,10-trioxo-2,4,6,8,9,11-hexaaza[3.3.3]propellane (THAP) with concentrated nitric acid. It was found that in the process of nitration, there are two competing reactions - lactam-lactam rearrangement and nitration. It was shown that the reaction products strongly depend on the temperature of the reaction mixture. It was found that at a temperature of -40 ºС the formation of the lactimic form of THAP proceeds, whereas with a gradual increase in temperature, a mononitro derivative of propellane is first formed, and at a temperature of 40 ºС, the selective formation of 3,7,10-trioxo-2,6-dinitro-2,4,6,8,9,11-hexaaza[3.3.3]propellane in 30% yield.

scholarly journals PROPELLANS – PERSPECTIVE FRAME COMPOUNDS FOR THE CREATION OF HIGH-ENERGY SUBSTANCES

2021 ◽  
pp. 91-95
Author(s):  
А.А. Минакова ◽  
С.Г. Ильясов
Keyword(s):  
Theoretical Calculations ◽  
Research Work ◽  
High Energy ◽  
Biologically Active ◽  
Heats Of Formation ◽  
Nitro Derivatives ◽  
Successive Substitution ◽  
The Creation ◽  
Derivatives Of ◽  
Active Substances

Гетероциклические соединения вызывают большой интерес у исследователей как потенциальные соединения в создании биологически активный веществ или веществ с высокой энергией. 3,7,10-Триоксо-2,4,6,8,9,11-гексааза[3.3.3]пропеллан (ТНАР) состоит из трех конденсированных колец, соединенных одинарной связью C1-C5 является новым, малоизученным веществом, синтезированным во втором десятилетии XXI века. Теоретические расчеты энергий нитропроизводных пропелланов с пятью или шестью атомами азота показали перспективность использования в качестве высокоэнергетических веществ. Целью работы было проведение квантово-химических расчетов теплоты образования и сгорания, а также длины пропеллановой связи нитро- и ацетилпроизводных 3,7,10-триоксо-2,4,6,8,9,11-гексааза[3.3.3]пропеллана и его восстановленного аналога 2,4,6,8,9,11-гексааза[3.3.3]пропеллана (НАР) с различным количеством заместителей. В результате исследовательской работы была выявлена следующая закономерность: последовательное введение нитрогрупп в изучаемую структуру увеличивает теплоты образования получаемых производных, тогда как для ацетильных групп тенденция противоположная. Оказалось, что гексанитропроизводное ТНАР по термодинамической стабильности сравнимо с гексанитробензолом, а восстановленный пропеллан НАР с шестью нитрогруппами сравним с CL-20. Поведение длины пропеллановой связи C1-C5 при последовательном замещении соединения ТНАР нитро- и ацетильными группами. Накопление ацетильных групп вызывает монотонное укорочение этой связи, вплоть до обычной длины C(sp3)-C(sp3). В случае нитрогрупп тенденция более сложная: сначала укорочение, а затем значительное удлинение, до 1.67 Å для шести нитрогрупп в 3,7,10-триоксо-2,4,6,8,9,11-гексанитро-2,4,6,8,9,11-гексааза[3.3.3]пропеллане. Гексаазапропеллан (НАР), несмотря на нежесткую структуру, имеет 22 стабильных конформера, тогда как у ТНАР их 2, и более короткие связи, что вероятно в дальнейшем позволит синтезировать его гексанитро производное. Heterocyclic compounds are of great interest to researchers as potential compounds in the creation of biologically active substances or substances with high energy. 3,7,10-Trioxo-2,4,6,8,9,11-hexaaza[3.3.3]propellane (THAP) consists of three condensed rings connected by a single C1-C5 bond, is a new, poorly studied substance synthesized in the second decade of the 21st century. Theoretical calculations of the energies of nitro-derivatives of propellanes with five or six nitrogen atoms have shown that they are promising for use as high-energy substances. The aim of the work was to carry out quantum-chemical calculations of the heats of formation and combustion, as well as the length of the propellane bond of nitro- and acetyl derivatives of 3,7,10-trioxo-2,4,6,8,9,11-hexaaza[3.3.3]propellane, as well as its reduced analogue 2,4,6,8,9,11-hexaaza[3.3.3]propellane (HAP) with a different number of substitutes. As a result of the research work, the following regularity was revealed: the successive introduction of nitro groups into the structure under study increases the heats of formation of the resulting derivatives, while the trend is opposite for acetyl groups. It turned out that the hexanitro derivative of THAP is comparable in thermodynamic stability to hexanitrobenzene, and the reduced propellane (HAP) with six nitro groups is comparable to CL-20. Behavior of the C1-C5 propellane bond length upon successive substitution of THAP compound with nitro- and acetyl groups. The accumulation of acetyl groups causes a monotonic shortening of this bond, up to the usual length of C(sp3)-C(sp3). In the case of nitro groups, the trend is more complex: first, shortening and then significant lengthening, up to 1.67 Å for six nitro groups in 3,7,10-trioxo-2,4,6,8,9,11-hexanitro-2,4,6, 8,9,11-hexaaza[3.3.3]propellane. Hexaazapropellane (HAP), despite its non-rigid structure, has 22 stable conformers, whereas THAP has two, and shorter bonds, which is likely to make it possible to synthesize its hexanitro derivative in the future.

Collision-induced dissociation of stable nitroxides: A combined tandem mass spectrometry and computational study of TEMPO• and SG1•

2019 ◽  
Vol 25 (2) ◽  
pp. 229-238
Author(s):  
Anouk Gaudel-Siri ◽  
Cathie Marchal ◽  
Vincent Ledentu ◽  
Didier Gigmes ◽  
Didier Siri ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Tandem Mass Spectrometry ◽  
Computational Study ◽  
Theoretical Calculations ◽  
Energy Transition ◽  
High Energy ◽  
Major Product ◽  
Tandem Mass ◽  
Reaction Products ◽  
Product Ions

The dissociation behavior of two stable nitroxides, namely 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO•) and N-tert-butyl-1-diethylphosphono-2,2-dimethylpropyl nitroxide (SG1•), subjected as protonated molecules to collisional activation was investigated using a combination of different mass spectrometry experiments and theoretical calculations. Elemental composition of reaction products was derived from accurate mass data measured in high resolution tandem mass spectrometry experiments, primary fragments were distinguished from secondary ions based on both breakdown curves and MS3 data, and H/D exchange experiments were performed to support proposed structures. Postulated fragmentation pathways were then studied in terms of energetic, using the standard B3LYP/6-31G(d) method. While protonation of TEMPO• mainly occurred on the oxygen atom of the nitroxyl function, a series of protomers were found for SG1• with the adducted proton preferentially located onto the P=O group of this phosphorylated species. For both protonated nitroxides, major product ions measured in tandem mass spectrometry arose from reactions occurring at low energy costs via elimination of radical species. Formation of secondary fragments that were detected with low abundance when raising the activation level of both precursor ions could be rationalized with pathways proceeding via high energy transition states.

scholarly journals Insights on forming N,O-coordinated Cu single-atom catalysts for electrochemical reduction CO2 to methane

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yanming Cai ◽  
Jiaju Fu ◽  
Yang Zhou ◽  
Yu-Chung Chang ◽  
Qianhao Min ◽  
...  
Keyword(s):  
Energy Barrier ◽  
Active Sites ◽  
Theoretical Calculations ◽  
High Energy ◽  
Single Atom ◽  
Faradaic Efficiency ◽  
High Energy Barrier ◽  
Catalytic Sites ◽  
Electron Reduction ◽  
First Time

AbstractSingle-atom catalysts (SACs) are promising candidates to catalyze electrochemical CO2 reduction (ECR) due to maximized atomic utilization. However, products are usually limited to CO instead of hydrocarbons or oxygenates due to unfavorable high energy barrier for further electron transfer on synthesized single atom catalytic sites. Here we report a novel partial-carbonization strategy to modify the electronic structures of center atoms on SACs for lowering the overall endothermic energy of key intermediates. A carbon-dots-based SAC margined with unique CuN2O2 sites was synthesized for the first time. The introduction of oxygen ligands brings remarkably high Faradaic efficiency (78%) and selectivity (99% of ECR products) for electrochemical converting CO2 to CH4 with current density of 40 mA·cm-2 in aqueous electrolytes, surpassing most reported SACs which stop at two-electron reduction. Theoretical calculations further revealed that the high selectivity and activity on CuN2O2 active sites are due to the proper elevated CH4 and H2 energy barrier and fine-tuned electronic structure of Cu active sites.

Angle and energy characteristics of neutrons produced by a high-energy ion beam

1989 ◽  
Vol 66 (3) ◽  
pp. 249-251
Author(s):  
A. Polyanski ◽  
A. N. Sosnin
Keyword(s):  
Ion Beam ◽  
High Energy ◽  
Energy Characteristics

scholarly journals Carbon Substitution on N24Cages: Crossover between Triangular and Hexagonal Structures

2013 ◽  
Vol 2013 ◽  
pp. 1-6
Author(s):  
Carrie Sanders ◽  
Douglas L. Strout
Keyword(s):  
Theoretical Calculations ◽  
High Energy ◽  
Energy Materials ◽  
Cylindrical Structures ◽  
High Energy Materials ◽  
Energy Applications ◽  
Carbon Substitution ◽  
Complex Forms ◽  
The Stability ◽  
Carbon Inclusion

Complex forms of nitrogen are of interest for their potential as high-energy materials, but many all-nitrogen systems lack the stability for practical high-energy applications. Inclusion of carbon atoms in an otherwise all-nitrogen structure can increase stability. Nitrogen cages are known for energetically preferring cylindrical structures with triangular endcaps, but carbon cages prefer the pentagon-hexagon structure of the fullerenes. Previous calculations on N22C2have shown that carbon inclusion narrows the gap between triangular and fullerene-like structures. In the current study, three isomers of N24are used as frameworks for carbon substitution. Theoretical calculations are carried out on isomers of N20C4, N18C6, and N16C8, with the goal of determining what level of carbon substitution causes the carbon fullerene-like structures to become energetically preferred.

COMPRESSIVE STRENGTH AND EXPLOSIVE CHARACTERISTICS OF POLYMER-BONDED EXPLOSIVES BASED ON HEXOGEN AND FLUOROELASTOMERS

2020 ◽  
pp. 76-83
Author(s):  
Nguyen Trung Toan
Keyword(s):  
Compressive Strength ◽  
Vinylidene Fluoride ◽  
High Energy ◽  
High Chemical ◽  
Energy Characteristics ◽  
Coating Method ◽  
Polymer Bonded Explosives ◽  
Friction Sensitivity ◽  
The Impact ◽  
High Chemical Stability

This paper describes the formulation of two polymer-bonded explosives based on RDX (hexahydro-1,3,5- trinitro-1,3,5-triazine) and fluoroelastomer binders by the water-slurry coating method. The fluoroelastomers are poly(VDF-HFP) (vinylidene fluoride-hexafluoropropene copolymer) and poly(VDF-CTFE) (vinylidene fluoride-chlorotrifluoroethylene copolymer). It has been observed that the impact sensitivity and the friction sensitivity of PBX samples were significantly lower than that of the single RDX. Results also showed that two PBX formulations have high chemical stability, high energy characteristics, and equivalent to some PBX in the world. Finally, the compressive strength of these PBX compositions was found in the range of 8-12 MPa.

scholarly journals REACTIVITY OF NUCLEOPHILES AND α-EFFECT IN SUBSTITUTION PROCESSES AT ELECTRON - DEFICIENCY CENTERS

2020 ◽  
Vol 86 (7) ◽  
Author(s):  
Anatolii Popov ◽  
Illia Kapitanov ◽  
Anna Serdyuk ◽  
Aleksandr Sumeiko
Keyword(s):  
Organic Phosphorus ◽  
Organophosphorus Pesticides ◽  
Reaction Rates ◽  
Hydroxamic Acids ◽  
Phosphorus Compounds ◽  
Reaction Products ◽  
Electron Pairs ◽  
Alkyl Derivatives ◽  
Solvent Type ◽  
Electron Deficiency

The review analyzes issues related to the reactivity of nucleophiles and the manifestation of the α-effect in substitution processes at electron-deficient centers. The fundamental aspects of this phenomenon, as well as the possibilities and prospects of using α-nucleophiles in systems for the highly efficient degradation of substrates - ecotoxicants of various natures, are discussed. In the first part of the review such aspects were observed: inorganic α-nucleophiles as the most effective class of reagents for the decomposition of organic phosphorus compounds, hydroxylamine, its N-alkyl derivatives, oximes, and hydroxamic acids, reactivity of the НОО– anion in the processes of acyl group transfer, reactivity of oximate ions, inorganic α-nucleophiles as the basis of formulations for the degradation of neurotoxins, vesicants, and organophosphorus pesticides, design of inhibited acetylcholinesterase reactivators based on hydroxylamine derivatives, ways of structural modification of α-nucleophiles and systems based on them. The data on the reactivity of typical inorganic α-nucleophiles in the cleavage of acyl-containing substrates, including phosphorus acid esters, which provide abnormally high reaction rates in comparison with other supernucleophiles, are analyzed. Various types of such α-nucleophiles, features of their structure and reactivity are considered. It was shown that an important feature of hydroxylamine, oximes, and hydroxamic acids is the presence of a fragment with adjacent O and N (–N – O – H) atoms containing one or more lone electron pairs, which determines their belonging to the class of α-nucleophiles. It has been shown that a many of factors can be responsible for the manifestation of the α-effect and its magnitude, the main of which is the destabilization of the ground state of the nucleophile due to repulsion of lone electron pairs, stabilization of the transition state, the unusual thermodynamic stability of reaction products, solvation effects of the solvent, type of hybridization of the electrophilic center, etc.

scholarly journals Preparation of isocyanates by carbamates thermolysis on the example of butyl isocyanate

2019 ◽  
Vol 58 (4) ◽  
pp. 40-47
Author(s):  
Ratmir R. Dashkin ◽  
◽  
Dmitry A. Gordeev ◽  
Khusrav Kh. Gafurov ◽  
Sergey N. Mantrov ◽  
...  
Keyword(s):  
Gas Phase ◽  
High Performance ◽  
Gas Flow ◽  
Flow Reactor ◽  
Packed Column ◽  
Biologically Active ◽  
Dibutyltin Dilaurate ◽  
Reaction Products ◽  
Uv Detector ◽  
Laboratory Setup

Butyl isocyanate is widely distributed as a precursor for the production of a number of biologically active substances: fungicides, preservatives, insecticides, personal care products, etc. Nowadays, there are a number of methods for the preparation of isocyanates, which can be divided into liquid phase and gas phase. One of the perspective methods for the production of isocyanates is the thermolysis of carbamate and/or the actions of various reaction activating agents, accompanied by the elimination of alcohol, but this process is reversible, which greatly complicates its use in industry. The paper presents the results of studies of non-catalytic thermal decomposition of N-alkylcarbamates with the formation of alkylisocyanates on the example of butylisocyanate in the gas phase, flow reactor in a wide temperature range (200 to 450 °C). In addition, a series of experiments was carried out using a catalyst, dibutyltin dilaurate, in order to reduce the thermolysis temperature and increase the yield of the final product. To implement the isocyanate production process, an experimental laboratory setup, consisting of a gas flow meter (argon) regulator, a packed column (for heating) and a sorption solution tank, was developed and tested. The thermolysis of N-n-butylcarbamate was carried out in two variations: the preparation of an individual n-butylisocyanate and the passage of reaction products through a sorption solution linking the n-butyl isocyanate to N-n-butyl-N '-(1-phenylethyl)urea, which allows to estimate the yield of the target n-butylisocyanate without additional losses. The analysis of the obtained substances was carried out by high performance liquid chromatography with a UV detector (target product) and a mass detector (analysis of by-products). According to the results of research, a modification of the laboratory facility was proposed, as well as n-butylisocyanate was obtained with a yield of 49% on the basis of a new technique.

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