Formation Of Hydrogen Cyanide Research Articles

Kinetic analysis on the hydrogen cyanide formation in the premixed methane/ammonia flame

Hydrogen cyanide (HCN) is a highly toxic trace emission that may be generated during ammonia (NH3) blended hydrocarbon combustion. In this study, a new kinetic model was developed and validated to predict HCN formation in NH3-blended combustion. Key rate coefficients for nitrogen-substituted hydrocarbon species were critically reevaluated. Using a one-dimensional freely propagating flame model, the formation of HCN in laminar premixed CH4/NH3/air flames was systematically analyzed under various conditions. Results indicate that HCN emission increases with increasing equivalence ratio (ϕ) and non-monotonically changes with NH3 blending ratio (α). Under lean conditions, HCN is primarily formed from the decomposition of imine radicals and oxidized by O/OH inside the flame front. While under rich conditions, the HCN oxidation takes place in the post-flame region, making the emissions at the outlet highly dependent on the reaction residential time. Consequently, attention should be paid to HCN emissions under high NH3 blending fraction (α > 50 %), and ultra-rich conditions (ϕ > 1.2) at normal temperature and pressure. The peak emission of HCN occurred at α = 0.7 and ϕ = 1.45, reaching a lethal concentration (310 ppm) in 1D premixed flame. Complex CHi and NHi interaction reactions are exhibited in the formation of HCN. The overall formation route can be divided into methylamine oxidation routes and radical combinations routes, and the former is dominant under all conditions. Independently increasing temperature or pressure will reduce the HCN emission due to the increased post-oxidation of HCN and diminished reaction characteristic time, respectively. More complicated changes in HCN were shown when temperature and pressure were increased at the same time. However, emissions will fall to a negligible level when temperature and pressure exceed 600 K and 2 atm, suggesting minimal concern for HCN emissions in CH4/NH3 combustion under elevated pressure and temperature conditions.

The Complex (Organic) Puzzle of the Formation of Hydrogen Cyanide and Isocyanide on Interstellar Ice Analogues.

Aiming to constrain the surface formation of HCN and HNC in the dense interstellar medium on ice-covered dust grains, we investigate the interaction of CN radicals with H2O and CO ices and their subsequent reactivity with H and H2. CN radicals can physisorb on both ices. However, on H2O ice, a hemibond formation is the most common binding mode, while on CO ice, the CN-CO van der Waals complex can form NCCO with a small energy barrier. We show low barrier or barrierless pathways to the formation of HCN and HNC for the reaction H + CN on both ices. Reactivity with H2 involves activation energy barriers to form HCN, which may be overcome by quantum tunneling, while HNC formation is unlikely. The formation of HCN and HNC competes with the formation of NH2CHO on H2O and HCOCN on CO.

Predicting Cyanide Degradability and Destruction Using Artificial Neural Networks: A Case Study in West Azerbaijan, Iran”

ABSTRACT The presence of cyanide compounds in soil can lead to the formation and evaporation of hydrogen cyanide (HCN), while some of these compounds can undergo conversion by microorganisms present in the soil. However, high concentrations of cyanide can be toxic to soil microorganisms. During the gold extraction of mines, sodium cyanide (NaCN) solution is commonly used which results in a significant amount of cyanide waste that is regarded as an environmental pollutant. Previous studies have proposed physical, chemical, and biological methods to eliminate cyanide, but they have not achieved optimal efficiency. Unfortunately, the potential of artificial intelligence (AI) in this domain has been overlooked. Artificial Neural Network (ANN) models, specifically the multilayer perceptron (MLP) and simple linear regression, can significantly enhance and expedite the cyanide remediation process due to their remarkable predictive capabilities. In this study, an MLP and simple linear regression were employed to predict the biodegradation procedures of cyanide in soil. The study focused on cyanide waste generated by gold extraction factories and utilized environmental factors such as initial waste cyanide concentration, pH, soil and environmental temperature, humidity, chloride concentration, alkaline, electrical conductivity, precipitation, evaporation intensity, cyanide concentration, and initial pH as input data for the artificial neural network. The results of the MLP model revealed that electrical conductivity is the most influential factor in predicting the cyanide rate and initial pH of the waste soil. Conversely, the results of the simple linear regression indicated that the variables with the greatest impact on cyanide concentration are electrical conductivity (0.881), time (0.862), and alkalinity (0.724). By leveraging AI techniques such as ANN, this study demonstrates the potential for improved cyanide remediation. The integration of environmental factors and predictive models can contribute to more effective strategies for addressing cyanide pollution in soil.

Endophytic Bacteria; Diversity, Characterization and Role in Agriculture

Entophytic bacteria have an important role in the growth process and health of the plant host. Nevertheless, also some endophytic bacteria are existing in seeds and have not been studied yet. In addition, some Entophytic bacteria are important in plant tolerance to environmental stresses. They can colonize the internal tissues of the host and are able to use a variety of different relations including symbiotic, mutualism, communalistic, and trophobiotic. They have the ability for plant hormone production like auxin, indole acetic acid, and gibberellin; also some endophytic bacteria have the ability for siderophore creation, phosphate solubilization, nitrogen fixation, protease, and hydrogen cyanide formation.. Moreover, they produce compounds that could have possible usage in drug, agriculture or engineering. They have the ability to removesoil toxins thus, improving phytoremediation and soil fertility. Further, most of endophytic bacteria are diazotrophs and associated with the Proteobacteria, and a varied range has been detected agreeing to the nifH gene which codes for nitrogenase enzyme, structures recovered from plant materials, however a limited part of these genes looks to be stated. The endophytes discussed in this review are isolated from surface-disinfested plant tissue, and that do not damage the plant. Moreover, endophytes appear to be in-between saprophytic bacteria and plant pathogens, they are either saprophytes growing to be pathogens, or extremely grown plant pathogens with protective accommodation and nutrient provisions, but not killing their host. Generally, endophytic bacteria are partial under biotic and abiotic influences, with the plant itself being one of the main prompting influences.

The nitrogen transformation and controlling mechanism of NH3 and HCN conversion during the catalytic pyrolysis of amino acid

Pyrolysis can convert biomass into sustainable chemicals and fuels, but the nitrogen compounds in its non-lignocellulosic components may produce hazardous NOx and its precursors. In this paper, catalytic pyrolysis of glutamic acid (Glu), used as a representing compound for biomass nitrogen source, was investigated at bench scale to study the transformation of the nitrogen element and the mechanism of Ammonia (NH3) and Hydrogen Cyanide (HCN) formation. The yields of the liquid, gaseous and solid products and the distribution of nitrogen compounds were systematically analysed. The experimental results showed that catalytic pyrolysis with H-ZSM-5 could increase the nitrogen compounds in the gas product from 38.54 % to 53.95 %, while it can reduce the nitrogen in the tar and char by 69.22 % and 58.07 %, respectively. The result of Density Functional Theory (DFT) study showed that the deamination to ternary cyclic ethers was the optimum pathway for NH3 formation. The formation of HCN has been dominated by the removal of side chain groups (reaction path 8). The energy barrier of the reaction path 9 was reduced to a level comparable to the energy barrier of path 8 during the catalytic pyrolysis, which may compete with each other. The 8T cluster model of the H-ZSM-5 catalyst revealed that the hydrogen bond formed between the acid sites and the reactants played an significant role in decreasing the reaction energy barrier. The experimental and computational results demonstrated the controlling mechanism of acid sites on the production of NH3 and HCN compounds and provided fundamental understanding to nitrogen transformation during the biomass pyrolysis.

Low-Temperature Activation of Methane with Nitric Oxide and Formation of Hydrogen Cyanide over an Alumina-Supported Platinum Catalyst

This study demonstrated methane activation with subsequent conversion to hydrogen cyanide (HCN) at low temperatures using nitric oxide (NO) as the sole oxidant together with an alumina-supported platinum catalyst (Pt/Al2O3). This process afforded HCN even at 300 °C, indicating that C–H bond cleavage, NO dissociation, and simultaneous C–N coupling all occurred at this reduced reaction temperature. The HCN yield increased with increasing temperature, resulting in a 3.2% yield with a selectivity of 49% at 425 °C. This yield was much greater than that obtained from the reaction of CH4 with NH3 and O2, which suggests a reaction mechanism different from the Andrussow process. The HCN production rate was 11.4 mmol g–1 h–1 and the corresponding turnover frequency was 253 h–1, both of which were far superior to those obtained in previous studies at similar reaction temperatures. The Pt catalyst was found to be stable and could continuously produce HCN for at least 100 h. In situ X-ray absorption fine structure analyses suggested that the high resistance of this material to deep oxidation facilitated HCN formation. The difference between X-ray absorption near-edge structure spectra before and during the reaction indicated that the specific adsorbates on the catalyst were dependent on the reaction temperature and that the extent of adsorbed Pt-CN species was correlated with the reactivity of the material.

Experimental-theoretical approach to calculating the partial density of hydrogen cyanide during fires at energy facilities

It is made analysis of toxic effect of hydrogen cyanide on people during fire evacuation at energy facilities premises. The critical value of the partial density of hydrogen cyanide is substantiated. An experimental and theoretical approach is proposed for calculating the partial density of hydrogen cyanide indoor fire. The proposed approach is based on the analytical dependence of the average volumetric partial density of HCN on the change in the volumetric average partial density of oxygen in the premises. The results of experiments on measuring the partial density of HCN in the case of combustion of modern cable products used at energy facilities are presented. The results of experimental and theoretical studies make it possible to determine the time variation of the average volumetric partial density of hydrogen cyanide in a fire in a full-scale premises using the experimental values of the specific coefficients of formation of hydrogen cyanide and oxygen absorption obtained in a small-scale experimental setup, and the change of the volumetric average partial density of oxygen obtained from the solution of the conservation law equation mass of oxygen. It is substantiated that the calculation can also be made without solving the differential equation of the law of conservation of the mass of hydrogen cyanide using only the experimental dependence of the HCN density on the change in O2 density.

One-Pot Hydrogen Cyanide-Based Prebiotic Synthesis of Canonical Nucleobases and Glycine Initiated by High-Velocity Impacts on Early Earth.

Chemical environments of young planets are assumed to be significantly influenced by impacts of bodies lingering after the dissolution of the protoplanetary disk. We explore the chemical consequences of impacts of these bodies under reducing planetary atmospheres dominated by carbon monoxide, methane, and molecular nitrogen. Impacts were simulated by using a terawatt high-power laser system. Our experimental results show that one-pot impact-plasma-initiated synthesis of all the RNA canonical nucleobases and the simplest amino acid glycine is possible in this type of atmosphere in the presence of montmorillonite. This one-pot synthesis begins with de novo formation of hydrogen cyanide (HCN) and proceeds through intermediates such as cyanoacetylene and urea.

Defining the specific formation coefficient and the critical partial density of hydrogen cyanide and carbon monoxide at the fire indoors

Introduction . Modern mathematical models of the distribution of toxic gases use the values of specific coefficients of formation of only three gases. It is not considered the whole spectrum of toxic gases produced during the combustion of synthetic materials. Therefore, the experimental study of the process of hydrogen cyanide formation is an important task. Aims and purposes. The purpose of this article is to develop a methodology for obtaining initial data on the release of hydrogen cyanide. These data are necessary to calculate the time of blocking evacuation ways. To achieve it, the value of the critical concentration of hydrogen cyanide was justified. The experimental unit was modernized and experimental studies of partial densities of hydrogen cyanide and carbon monoxide, as well as specific coefficients of their release, were carried out during combustion of modern cable products. Methods . An experimental method is used to study the process of formation of hydrogen cyanide and carbon mono­xide during the combustion of samples of cable products in a modernized small-size experimental unit. The results were analyzed. Results . The critical value of the partial density of hydrogen cyanide, presented in normative documents, on the basis of analysis of data given in the literature sources, is substantiated. Experimental dependences between the time of testing and partial densities of hydrogen cyanide and carbon monoxide, as well as their specific coefficients of release, were obtained. This study reveals that the experimental value of the partial density of hydrogen cyanide reaches a critical value. That fact justifies the need to calculate the time of blocking the escape routes with con­sidering influence of hydrogen cyanide. Conclusion . The modernization of the experimental unit makes it possible to obtain experimental dependencies on the time of partial densities of hydrogen cyanide and carbon monoxide, as well as specific coefficients of their separation. This makes it possible to update (by HCN and CO) the existing database of typical fire load and to calculate the time of blocking the escape routes in case of combined effects of the above mentioned gases. When calculating fire risks in case of the burning of modern cable products, it is necessary to determine the time of blocking evacuation routes by hydrogen cyanide.

Hydrogen cyanide in nitrogen-rich atmospheres of rocky exoplanets

Hydrogen cyanide (HCN) is a key feedstock molecule for the production of life's building blocks. The formation of HCN in an N2-rich atmospheres requires first that the triple bond between N≡N be severed, and then that the atomic nitrogen find a carbon atom. These two tasks can be accomplished via photochemistry, lightning, impacts, or volcanism. The key requirements for producing appreciable amounts of HCN are the free availability of N2 and a local carbon to oxygen ratio of C/O ≥ 1. We discuss the chemical mechanisms by which HCN can be formed and destroyed on rocky exoplanets with Earth-like N2 content and surface water inventories, varying the oxidation state of the dominant carbon-containing atmospheric species. HCN is most readily produced in an atmosphere rich in methane (CH4) or acetylene (C2H2), but can also be produced in significant amounts (>1 ppm) within CO-dominated atmospheres. Methane is not necessary for the production of HCN. We show how destruction of HCN in a CO2-rich atmosphere depends critically on the poorly-constrained energetic barrier for the reaction of HCN with atomic oxygen. We discuss the implications of our results for detecting photochemically produced HCN, for concentrating HCN on the planet's surface, and its importance for prebiotic chemistry.

CH3NO as a potential intermediate for early atmospheric HCN: a quantum chemical insight.

Hydrogen cyanide (HCN) has played a central role in the production of several biological molecules under prebiotic conditions on primitive Earth. Previously, K. J. Zahnle (J. Geophys. Res.: Atmos., 1986, 91, 2819) and Tian et al. (Earth Planet. Sci. Lett., 2011, 308, 417) emphasized that HCN production in the early Earth's CH4-rich atmosphere could have been possible through the reaction between active nitrogen atoms (N) and methane photolysis products. Here, we have proposed alternative pathways for the formation of early atmospheric HCN via the decomposition of CH3NO as an intermediate. In the early Earth's O2-free atmosphere, CH3˙ could preferentially attach to NO, which was generated via early atmospheric volcanism or lightning and photochemical processes. We have quantum chemically explored both unimolecular and bimolecular decomposition pathways of CH3NO via the assistance of another CH3NO molecule and via H2O, NH3, HCl, HCOOH, HNO3 and H2SO4 catalysis. Both energetic and kinetic analyses reveal that H2SO4 is more efficient in this regard than other atmospheric species. Overall, it has been suggested that the proposed bimolecular decomposition pathways might have been alternative pathways for the formation of HCN under certain conditions on prebiotic Earth, while the unimolecular decomposition of CH3NO could lead to the formation of HCN in the high temperature volcanic environment on early Earth.

Lewis adduct formation of hydrogen cyanide and nitriles with arsenic and antimony pentafluoride.

The reactions of hydrogen cyanide, butyronitrile, cyclopropanecarbonitrile, pivalonitrile and benzonitrile with arsenic pentafluoride and antimony pentafluoride result in the formation of 1 : 1 Lewis adducts, while malononitrile yielded both 1 : 1 and 1 : 2 Lewis adducts. All adducts were isolated and characterized by multinuclear NMR and vibrational spectroscopy, and in most cases by their X-ray crystal structures.

Isocyanates and hydrogen cyanide in fumes from heated proteins and protein-rich foods.

Toxic compounds in cooking fumes could cause respiratory problems. In the present study, the formation of isocyanic acid (ICA), methyl isocyanate (MIC), and hydrogen cyanide (HCN) was studied during the heating of proteins or frying of protein-rich foods. Heating was performed in an experimental setup using a tube oven set at 200-500°C and in a kitchen when foods with different protein content were fried at a temperature around 300°C. ICA, MIC, and HCN were all generated when protein or meat was heated. Individual amino acids were also heated, and there was a significant positive correlation between their respective nitrogen content and the formation of the measured compounds. Gas from heated protein or meat also caused carbamylation in albumin. ICA, MIC, and HCN were also present in fumes generated when meat, egg, and halloumi were fried in a kitchen pan. The levels of ICA were here twice that of the Swedish occupational exposure limit. If ICA, MIC, and HCN in fumes from heated protein-rich foods could contribute to the risk of airway dysfunction among those exposed is not clear, but it is important to avoid inhaling frying and grilling fumes and to equip kitchens with good exhaust ventilation.

RESEARCH OF THE INFLUENCE OF THE COMPOSITION OF THE INITIAL GAS MIXTURE ON THE FORMATION OF HYDROGEN CYANIDE

The main results of research on the influence of the composition of the initial gas mixture on the formation of hydrogen cyanide by the oxidative ammonolysis of methane is considered. Industrial production of hydrogen cyanide is the basis for the production of one of the important components in gold mining, sodium cyanide. Today, the main method of production of sodium cyanide is based on the neutralization of hydrocyanic acid obtained by the catalytic synthesis of methane, ammonia and oxygen of the air on a platinum catalyst, with an alkali solution. This method has been little studied and has great prospects for its further improvement. The purpose of the study was to establish the optimal ratio of the components of the initial gas mixture and their influence on the output of hydrogen cyanide. In oxidative ammonolysis of methane, taking into account the uneven diffusion of gases and lower cost of methane, compared with ammonia, the process of producing hydrogen cyanide is carried out with a small excess of methane relative to ammonia. It has been established that with a reduced content of one of the reactants in the initial gas mixture after the reactor of hydrogen cyanide synthesis, a significant amount of unreacted components of the mixture is present in the contact gas. It was revealed that the degree of conversion of reagents into hydrogen cyanide depends not only on the initial concentration, but also on their ratio in the initial mixture. It is proved that the maximum degree of conversion of ammonia and methane is achieved when the ratio of ammonia / methane in the reaction mixture is 0.9-0.95. The maximum yield of hydrogen cyanide by oxidative ammonolysis of methane is 62–72 % and is achieved when the ratio of components in the initial reaction mixture when the ratio of ammonia / methane is 0.8–0.9. The effect of temperature on the formation of hydrogen cyanide by the Andrussov method has been investigated. It has been established that increasing the temperature of the process for producing hydrogen cyanide by the oxidative ammonolysis of methane has a positive effect on the yield of the target product. The results obtained can be used in modern nitrogen-fertilizer plants to optimize the process of synthesis of hydrocyanic acid.

Glutathione transferases catalyze recycling of auto-toxic cyanogenic glucosides in sorghum.

Cyanogenic glucosides are nitrogen-containing specialized metabolites that provide chemical defense against herbivores and pathogens via the release of toxic hydrogen cyanide. It has been suggested that cyanogenic glucosides are also a store of nitrogen that can be remobilized for general metabolism via a previously unknown pathway. Here we reveal a recycling pathway for the cyanogenic glucoside dhurrin in sorghum (Sorghum bicolor) that avoids hydrogen cyanide formation. As demonstrated invitro, the pathway proceeds via spontaneous formation of a dhurrin-derived glutathione conjugate, which undergoes reductive cleavage by glutathione transferases of the plant-specific lambda class (GSTLs) to produce p-hydroxyphenyl acetonitrile. This is further metabolized to p-hydroxyphenylacetic acid and free ammonia by nitrilases, and then glucosylated to form p-glucosyloxyphenylacetic acid. Two of the four GSTLs in sorghum exhibited high stereospecific catalytic activity towards the glutathione conjugate, and form a subclade in a phylogenetic tree of GSTLs in higher plants. The expression of the corresponding two GSTLs co-localized with expression of the genes encoding the p-hydroxyphenyl acetonitrile-metabolizing nitrilases at the cellular level. The elucidation of this pathway places GSTs as key players in a remarkable scheme for metabolic plasticity allowing plants to reverse the resource flow between general and specialized metabolism in actively growing tissue.

Identification of On-Surface Reaction Mechanism by Targeted Metalation

Chemical reactions occurring on surfaces may provide an alternate route to materials beyond traditional methods, for example, large polymers or compounds that would react further in ambient conditions or lack solubility. Many on-surface reactions yield atomic hydrogen that then desorbs swiftly from noble metals of group 11 (Cu, Ag, Au). Using a porphyrin-related macrocycle, so-called pyrphyrin, also bearing two cyano groups at the periphery, we show that dehydrogenation of the center of the macrocycle leads to selective formation of hydrogen cyanide, created from the rim-cyano groups and the hydrogen of the center imine (═NH). Formally, the surface-remaining reaction product is a dicarbene, bearing two divalent carbon atoms. It reacts readily with Fe atoms at room temperature, unlike its pyrphyrin precursor, which requires annealing for metalation with Fe. The hydrogen cyanide abstraction becomes suppressed when pyrphyrin is metalated with iron atoms because the absence of the two hydrogen atoms does not ...

Thermogravimetric and qualitative analysis of thermal decomposition characteristics of polyurethane foams based on polyols with carbamide or oxamide and borate groups

The thermal stability and the kinds of products of thermal decomposition of polyurethane foams modified with urea or oxamide and borate groups were studied. Incorporation of urea or oxamide groups and borate groups enhances the thermal stability of polyurethane foams compared to polyurethane foams based on typical polyols. Thermal stability of foams modified with oxamide groups is somewhat higher that of foams modified with urea groups. In turn, simultaneous incorporation of borate groups results in an increase in thermal stability of the foams modified with urea. The temperature of thermal decomposition of the foams with oxamide and borate groups does not change or undergoes a slight decrease. The thermal degradation products of investigated foams are similar and they are usually water, ammonia, carbon dioxide and/or nitrous oxide. Additionally, hydrogen cyanide can be released during thermal decomposition of polyurethane foams modified with urea groups. The presence of borate groups prevents the formation of hydrogen cyanide. The opposite situation is observed in the case of the foams modified with oxamide and borate groups. Thus, from the point of view of a fire hazard, the use of the foams modified with urea and borate groups is safer. © 2017 Society of Chemical Industry

A DFT Investigation of the Mechanism of Propene Ammoxidation over α-Bismuth Molybdate

The mechanisms and energetics for the propene oxidation and ammoxidation occurring on the (010) surface of Bi2Mo3O12 were investigated using density functional theory (DFT). An energetically feasible sequence of elementary steps for propene oxidation to acrolein, propene ammoxidation to acrylonitrile, and acrolein ammoxidation to acrylonitrile is proposed. Consistent with experimental findings, the rate-limiting step for both propene oxidation and ammoxidation is the initial hydrogen abstraction from the methyl group of propene, which is calculated to have an apparent activation energy of 27.3 kcal/mol. The allyl species produced in this reaction is stabilized as an allyl alkoxide, which can then undergo hydrogen abstraction to form acrolein or react with ammonia adsorbed on under-coordinated surface Bi3+ cations to form allylamine. Dehydrogenation of allylamine is shown to produce acrylonitrile, whereas reaction with additional adsorbed ammonia leads to the formation of acetonitrile and hydrogen cyanide....

A revision in hydrogen isotopic composition of USGS42 and USGS43 human-hair stable isotopic reference materials for forensic science

The hydrogen isotopic composition (δ2HVSMOW-SLAP) of USGS42 and USGS43 human hair stable isotopic reference materials, normalized to the VSMOW (Vienna-Standard Mean Ocean Water)–SLAP (Standard Light Antarctic Precipitation) scale, was originally determined with a high temperature conversion technique using an elemental analyzer (TC/EA) with a glassy carbon tube and glassy carbon filling and analysis by isotope-ratio mass spectrometer (IRMS). However, the TC/EA IRMS method can produce inaccurate δ2HVSMOW-SLAP results when analyzing nitrogen-bearing organic substances owing to the formation of hydrogen cyanide (HCN), leading to non-quantitative conversion of a sample into molecular hydrogen (H2) for IRMS analysis. A single-oven, chromium-filled, elemental analyzer (Cr-EA) coupled to an IRMS substantially improves the measurement quality and reliability of hydrogen isotopic analysis of hydrogen- and nitrogen-bearing organic material because hot chromium scavenges all reactive elements except hydrogen. USGS42 and USGS43 human hair isotopic reference materials have been analyzed with the Cr-EA IRMS method, and the δ2HVSMOW-SLAP values of their non-exchangeable hydrogen fractions have been revised:USGS42(Tibetan Hair) δ2HVSMOW−SLAP=−72.9±2.2 mUr (n=6)USGS43(Indian Hair) δ2HVSMOW−SLAP=−44.4±2.0 mUr (n=6)where mUr=0.001=‰. On average, these revised δ2HVSMOW-SLAP values are 5.7mUr more positive than those previously measured. It is critical that readers pay attention to the δ2HVSMOW-SLAP of isotopic reference materials in publications as they may need to adjust the δ2HVSMOW–SLAP measurement results of human hair in previous publications to ensure all results are on the same isotope-delta scale.

The Problems of Emission of Hydrogen Cyanide Reduction in the Production of Coke

Escaped in the production of coke hydrogen cyanide is toxic dangerous substance. And control of its content during the process is very difficult. There were considered urgent tasdks associated with a reduction in the negative impact of hydrogen cyanide emissions generated in the production of coke-chemical production that are solved with the help of mathematical modelling. There was offered sert of effective measures to ensure the reduction of hydrogen cyanide emissions by chimneys of coke battareis. There was elaborated mathematical model of formation of hydrogen cyanide, which provides the relationship of vhemical kinetics and thermodynamics of the process, wehich allows to identify ways to ensure stable operation of coke battareis.