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A novel Pd-Fe/α-Al2O3 catalyst was synthesized by incipient-wetness impregnation method with bayberry tannin as chelating promoter and commercial hollow column Raschig ring α-Al2O3 as support for the synthesis of diethyl oxalate from CO and ethyl nitrite. A variety of characterization techniques including N2 physical adsorption, optical microscopy, scanning electron microscopy and energy dispersive system (SEM-EDS), inductively coupled plasma optical emission spectroscopy (ICP-OES), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), were employed to explore the relationship between the physicochemical properties and activity of catalysts. It indicated that a large number of phenolic hydroxyl groups in bayberry tannin can efficiently anchor the active component Pd, reduce the particle size and make the active Pd as a multi-ring distribution on the commercial α-Al2O3 support, which were beneficial to improve the catalytic activity for the production of diethyl oxalate from CO and ethyl nitrite. 0.3 wt% Pd-Fe/α-Al2O3 showed excellent catalytic activity and selectivity in a continuous flow, fixed-bed reactor with the loading amount of 10 mL catalysts. Under the mild reaction conditions, the space-time yield of diethyl oxalate was 978 g L−1 h−1 and CO conversion was 44% with the selectivity to diethyl oxalate of 95.5%.

The reactions of diaryl-, aryl-, and alkyl–arylcyclopropanes with ethyl nitrite in the presence of sulfur trioxide and sulfur trioxide dioxane complex, as well as the reactions of 1-alkyl-2-arylcyclopropanes with NOBF4 were studied. It was found that the attack of the nitrosonium cation, accompanied by the formation of a benzyl carbocation, leads to the formation of isoxazolines. The introduction of bulky alkyl substituents into the cyclopropane ring changes the regioselectivity of nitrosation, favoring the attack of the electrophilic particle on the benzyl position and leading to the competitive formation of an alkyl carbocation. Depending on the structure of the alkyl substituent, both products of intramolecular heterocyclization accompanied by skeletal rearrangements and products formed with the participation of an external nucleophile are formed.

The diethyl oxalate process features two reaction sections with two of the fresh feeds (oxygen and ethanol) and a recycle stream containing nitric oxide fed into the first reactor, which produces ethyl nitrite and water. Water is removed in a distillation column and the ethyl nitrite is fed to the second reactor along with the third fresh feed (carbon monoxide). Diethyl oxalate and nitric oxide are produced in this reactor. The product diethyl oxalate is recovered in a distillation column, and the nitric oxide is recycled back to the first reactor. The intermediate components (nitric oxide and ethyl nitrite) and inert nitrogen circulate between the two reaction sections. A recent paper proposed a plantwide control structure for this complex process that requires four on-line composition controllers to handle disturbances in throughput and the compositions of the three fresh feed streams. The purpose of this paper is to demonstrate that a less complex control structure with only one composition measurement can achieve stable regulatory control.

Diethyl oxalate (DEO) is widely used in fine chemical industry. In comparison with traditional esterification process, carbon monoxide coupling process is a novel routine for DEO production. This environmentally friendly process provides better selectivity and yield. Its unique feature is that a closed regeneration-coupling circulation is formed. Toxic byproduct-nitric oxide (NO) from coupling reaction is recycled to re-produce ethyl nitrite through regeneration reaction. This avoids significant amount of NOx emission. However, due to a few NOx emission, a contaminant handling system is applied for environmental protection. A systematical environmental analysis is also carried out to assess this process. Regeneration-coupling circulation brings interaction behaviors and some trade-offs including reactor size and recycle flowrate, regeneration and coupling reaction, loss of reactants and NO emission. Thus, a rigorous steady simulation is established to investigate these trade-offs. Then DEO process is optimized to obtain the optimal design. Finally a more economic flowsheet to produce DEO is proposed.

The method for assessing the level of nitric oxide (II) (NO) by voltammetric monitoring of nitrite ions was carried out on models M1 and M2 of polarized macrophages induced from monocytes of human peripheral blood with the addition of lipopolysaccharide (LPS) and interleukin-4 (IL-4), respectively. The model of induction of M1 and M2 macrophages was used in the work to achieve the corresponding shifts in the functional status of studied cells. Ethyl nitrite (EtONO) was used as a standard compound of nitrite ions for electrochemical measurements. Electrochemical determination of nitrite ions was performed by anodic linear sweep voltammetry in the first-order derivative mode (ALSV FOD) in Britton-Robinson (BR) buffer with pH 4.02 on carbon ink modified graphite electrode. EtONO calibrations were linear over a concentration range from 2 to 9 μmol L−1 with corresponding regression equation y = 0.768c − 0.048. Limit of detection (LOD) (S/N = 3) was 0.38 μmol L−1. The results of the study showed the fundamental possibility of using voltammetry to assess indirectly the production of nitric oxide by cells in supernatants of the monocytic macrophage lineage. The level of nitric oxide metabolites (nitrite ions) in supernatants was associated with the functional state of macrophages.

Diethyl carbonate (DEC) is a well-known linear organic carbonate that has wide applications. Besides its use as a fuel additive, DEC is an excellent electrolyte for lithium ion batteries and is used for the production of polycarbonates, which are globally used engineering plastics. The synthesis of DEC from CO2 helps in CO2 mitigation. It was earlier synthesized by phosgenation of ethanol, which is a toxic and dangerous process. Certain non-phosgene routes have been developed in recent years, which include oxidative carbonylation of ethanol, trans-esterification of carbonate, alcoholysis of urea, ethanolysis of CO2 and the ethyl nitrite route for DEC synthesis. This review underlines various non-phosgene methods for the synthesis of DEC by critically evaluating the catalysts used, operating conditions and mechanism of synthesis. The performances of various catalysts have been compared graphically along with the identification of problems and potential solutions. Certain engineering aspects, including kinetics and thermodynamics of the various routes, have also been highlighted. The shortcomings and research gaps have been explicitly mentioned and discussed along with required future developments and research work for DEC synthesis.

Disruption of microvascular blood flow is a common cause of tissue hypoxia in disease, yet no therapies are available that directly target the microvasculature to improve tissue oxygenation. Red blood cells (RBCs) autoregulate blood flow through S-nitroso-hemoglobin (SNO-Hb)-mediated export of nitric oxide (NO) bioactivity. We therefore tested the idea that pharmacological enhancement of RBCs using the S-nitrosylating agent ethyl nitrite (ENO) may provide a novel approach to improve tissue oxygenation. Serial ENO dosing was carried out in sheep (1–400 ppm) and humans (1–100 ppm) at normoxia and at reduced fraction of inspired oxygen (FiO(2)). ENO increased RBC SNO-Hb levels, corrected hypoxia-induced deficits in tissue oxygenation, and improved measures of oxygen utilization in both species. No adverse effects or safety concerns were identified. Inasmuch as impaired oxygenation is a major cause of morbidity and mortality, ENO may have widespread therapeutic utility, providing a first-in-class agent targeting the microvasculature.

This study investigates the autoignition behavior of two gasoline surrogates doped with an alkyl nitrate cetane enhancer, 2-ethyl-hexyl nitrate (2EHN) to better understand dopant interactions with the fuels, including influences of accelerating kinetic pathways and enhanced exothermicity. A primary reference fuel (PRF) blend of n-heptane/iso-octane, and a toluene reference fuel (TRF) blend of n-heptane/iso-octane/toluene are used where the aromatic fraction of the latter is set to 20% (liquid volume), while the content of n-heptane is adjusted so that the overall reactivity of the undoped fuels is similar, e.g., Anti-Knock Index (AKI) of ∼91, Cetane Number (CN) ∼25. Doping levels of 0.1, 1.0 and 3.0% (liquid volume basis) are used where tests are conducted within a rapid compression machine (RCM) at a compressed pressure of 21 bar, covering temperatures from 675 to 1025 K with stoichiometric fuel–oxygen ratios at O2 = 11.4%. At the experimental conditions, it is found that the doping effectiveness of 2EHN is fairly similar between the two fuels, though 2EHN is more effective in the aromatic blend at the lowest temperatures, while it is slightly more effective in the non-aromatic blend at intermediate temperatures. Kinetic modeling of the experiments indicates that although some of the reactivity trends can be captured using a detailed model, the extents of predicted Cetane Number enhancement by 2EHN are too large, while differences in fuel interactions for the two fuels result in excessive stimulation of the non-aromatic blend. Sensitivity analysis using the kinetic model indicates that the CH2O and CH3O2 chemistry are very sensitive to the dopant at all conditions. The rate of 2EHN decomposition is only important at low temperatures where its decomposition rate is slow due to the high activation energy of the reaction. At higher temperatures, dopant-derived 3-heptyl radicals are predicted to play an important role stimulating ignition. Finally, nitrogen chemistry is important through the ’NO – NO2 loop’ where this can generate substantial amounts of OH. However, at the highest doping levels the formation of methyl and ethyl nitrite, and nitric acid significantly competes with this so that less OH is generated and this constrains the reactivity enhancement of 2EHN.

Chirped-pulse (CP) Fourier transform rotational spectroscopy is uniquely suited for near-universal quantitative detection and structural characterization of mixtures that contain multiple molecular and radical species. In this work, we employ CP spectroscopy to measure product branching and extract information about the reaction mechanism, guided by kinetic modeling. Pyrolysis of ethyl nitrite, CH3CH2ONO, is studied in a Chen type flash pyrolysis reactor at temperatures of 1000-1800 K. The branching between HNO, CH2O, and CH3CHO products is measured and compared to the kinetic models generated by the Reaction Mechanism Generator software. We find that roaming CH3CH2ONO → CH3CHO + HNO plays an important role in the thermal decomposition of ethyl nitrite, with its rate, at 1000 K, comparable to that of the radical elimination channel CH3CH2ONO → CH3CH2O + NO. HNO is a signature of roaming in this system.

5-Amino-4-hydroxyiminopyrazoles and (E)-N1-aryl-3-aryl-4-[(substitutedpyrazolyl)diazenyl]pyrazoles derivatives were conveniently synthesized as the corresponding products by reacting 5-aminopyrazoles with ethyl nitrite or sodium nitrite in ∼10% aqueous HCl solution. All of 5-amino-4-hydroxyiminopyrazoles and diazenes were fully identified by spectroscopic methods. Based on the single-crystal X-ray diffraction study, 5-amino-4-hydroxyiminopyrazole structure first identified and presented in this work as opposed to a nitroso tautomer.

Chiral β-hydroxy-β-arylalanine and β-methoxy-β-arylalanine derivatives, which occur widely in marine nature products, were stereoselectively synthesized with 99 % ee values. The two erythro isomers were prepared by L- or D-aminoacylase-catalyzed resolution of the corresponding N-acetyl derivatives, whereas the two threo isomers were obtained only by D-aminoacylase-catalyzed resolution of the derivatives. erythro-β-Hydroxy-β-arylalanine derivatives were prepared by diastereoselective hydrogenation of ethyl 2-(hydroxyimino)-3-oxo-3-arylpropanoates, which were in turn acquired by the oximation of ethyl 3-oxo-3-arylpropanoates with ethyl nitrite in the presence of nano-K2CO3 with yields of 72 % to 80 %. β-Methoxy-β-arylalanine derivatives were synthesized through Williamson reactions between the corresponding β-hydroxy-β-arylalanines and iodomethane with silver oxide as base.

Addition of nitroalkanes into n-alkanes can lower the activation barriers of free-radical production and accelerate the decomposition of n-alkanes at relatively low temperatures. Four initial decomposition mechanisms of the n-butane/nitroethane binary mixture were proposed for the promoting effect and considered theoretically at the B3LYP, BB1K, BMK, MPW1K, and M06-2X levels with MG3S basis set. Energetics above was compared to high-level CBS-QB3 and G4 calculations. Calculated results confirm the feasibility of the four initial decomposition pathways: (I) the CNO2 bond rupture of nitroethane to produce ethyl and ·NO2, (II) HONO elimination from nitroethane followed by decomposition to ·OH and ·NO, (III) rearrangement of nitroethane to ethyl nitrite which further dissociates into CH3CH2O· and ·NO, and (IV) direct hydrogen-abstraction of nitroethane with n-butane.

Diethyl carbonate (DEC) is a well-known linear organic carbonate that has wide applications. Besides its use as a fuel additive, DEC is an excellent electrolyte for lithium ion batteries and is used for the production of polycarbonates, which are globally used engineering plastics. The synthesis of DEC from CO2 helps in CO2 mitigation. It was earlier synthesized by phosgenation of ethanol, which is a toxic and dangerous process. Certain non-phosgene routes have been developed in recent years, which include oxidative carbonylation of ethanol, trans-esterification of carbonate, alcoholysis of urea, ethanolysis of CO2 and the ethyl nitrite route for DEC synthesis. This review underlines various non-phosgene methods for the synthesis of DEC by critically evaluating the catalysts used, operating conditions and mechanism of synthesis. The performances of various catalysts have been compared graphically along with the identification of problems and potential solutions. Certain engineering aspects, including kinetics and thermodynamics of the various routes, have also been highlighted. The shortcomings and research gaps have been explicitly mentioned and discussed along with required future developments and research work for DEC synthesis.

Background It is well known that ethanol can cause significant morbidity and mortality, and much of the related toxic effects can be explained by its metabolic profile. Objective This work performs a complete review of the metabolism of ethanol focusing on both major and minor metabolites. Method An exhaustive literature search was carried out using textual and structural queries for ethanol and related known metabolizing enzymes and metabolites. Results The main pathway of metabolism is catalyzed by cytosolic alcohol dehydrogenase, which exhibits multiple isoenzymes and genetic polymorphisms with clinical and forensic implications. Another two oxidative routes, the highly inducible CYP2E1 system and peroxisomal catalase may acquire relevance under specific circumstances. In addition to oxidative metabolism, ethanol also originates minor metabolites such as ethyl glucuronide, ethyl sulfate, ethyl phosphate, ethyl nitrite, phosphatidylethanol and fatty acid ethyl esters. These metabolites represent alternative biomarkers since they can be detected several hours or days after ethanol exposure. Conclusion It is expected that knowing the metabolomics of ethanol may provide additional insights to better understand the toxicological effects and the variability of dose response.

The syntheses of dimethyl oxalate (DMO) and diethyl oxalate (DEO) by CO coupling reaction in gaseous phase were investigated in a fixed bed reactor over Pd-Fe/Al2O3 catalyst. The catalytic performance was characterized by CO conversion, space-time yield (STY) and selectivity of DMO (or DEO). The results showed that over Pd-Fe/Al2O3 catalyst, the STY of DMO was higher than that of DEO under the same reaction conditions. The optimum reaction temperatures for synthesizing DMO and DEO were 403 K and 393 K, respectively, at the molar ratio 1:1 of alkyl nitrite to CO. The difference in synthesizing DMO and DEO on the same catalyst was attributed to the decomposition performances of methyl nitrite (MN) and ethyl nitrite (EN), as density functional theory (DFT) calculation showed that EN decomposed more easily than MN.

High catalytic activity of a gold N-containing ligand complex in the homogenous carbonylation of alkyl nitrite to dialkyl carbonate with KI as the promoter is reported. [AuCl 2 (phen)]Cl/KI (phen = 1,10-phenanthroline) complex has been used as a catalyst in the carbonylation of ethyl nitrite. The use of iodide as a promoter resulted in a significant increase in activity (TOF: 35.8 mol•mol Au − 1 •h − 1 ) and selectivity (91.7%) for diethyl carbonate at 3.0 MPa, 80 °C and 5 h. Based on the results of ESI-MS, UV-Vis, and cyclic voltammetry (CV) experiments, a mechanism is proposed for the carbonylation of alkyl nitrite in a homogeneous system using a gold N-containing ligand complex as a catalyst.

A novel Pd–Fe/α-Al 2 O 3 /cordierite monolithic catalyst was prepared for the synthesis of diethyl oxalate from CO and ethyl nitrite. The palladium-based monolithic catalyst with an optimal thickness (15 μm) of Al 2 O 3 washcoat showed excellent catalytic activity and selectivity in a continuous flow, fixed-bed microreactor. The physicochemical properties of catalyst were studied by a variety of characterization techniques. Catalytic performances of Pd–Fe/α-Al 2 O 3 /cordierite monolithic catalysts were dependent on particle size of alumina-sol, thickness of Al 2 O 3 washcoat, pore structure, surface acidity of carrier, and distribution of active metal component on the Al 2 O 3 washcoat. Under the mild reaction conditions, CO conversion was 32% and the space–time yield of diethyl oxalate was 429 g/(L h). Pd efficiency (DEO(g)/Pd(g)/h) of the monolithic catalyst (274 h −1 ) was much higher than that of a reference pellet catalyst (46 h −1 ), probably due to high dispersion of the Pd nanoparticles on the surface of the monolithic catalyst.

Background and Purpose— S -nitrosylated hemoglobin ( S -nitrosohemoglobin) has been implicated in the delivery of O 2 to tissues through the regulation of microvascular blood flow. This study tested the hypothesis that enhancement of S -nitrosylated hemoglobin by ethyl nitrite inhalation improves outcome after experimental subarachnoid hemorrhage (SAH). Methods— A preliminary dosing study identified 20 ppm ethyl nitrite as a concentration that produced a 4-fold increase in S -nitrosylated hemoglobin concentration with no increase in methemoglobin. Mice were subjected to endovascular perforation of the right anterior cerebral artery and were treated with 20 ppm ethyl nitrite in air, or air alone for 72 hours, after which neurologic function, cerebral vessel diameter, brain water content, cortical tissue P o 2 , and parenchymal red blood cell flow velocity were measured. Results— At 72 hours after hemorrhage, air- and ethyl nitrite–exposed mice had similarly sized blood clots. Ethyl nitrite improved neurologic score and rotarod performance; abated SAH-induced constrictions in the ipsilateral anterior, middle cerebral, and internal carotid arteries; and prevented an increase in ipsilateral brain water content. Ethyl nitrite inhalation increased red blood cell flow velocity and cortical tissue P o 2 in the ipsilateral cortex with no effect on systemic blood pressure. Conclusions— Targeted S -nitrosylation of hemoglobin improved outcome parameters, including vessel diameter, tissue blood flow, cortical tissue P o 2 , and neurologic function in a murine SAH model. Augmenting endogenous P o 2 -dependent delivery of NO bioactivity to selectively dilate the compromised cerebral vasculature has significant clinical potential in the treatment of SAH.

The synthesis of ethyl nitrite by the reaction of C 2 H 5 OH, O 2 , and NO, called the regeneration reaction in the synthesis of ethylene glycol (EG) by the coupling reaction-hydrogenation process, is carried out in a trickle bed reactor filled with θ-mesh rings at 313–343 K and atmospheric pressure. It is shown that the conversion of O 2 increases with the NO/O 2 and the EtOH/NO molar ratios, and decreases with the N 2 volume fraction and the liquid hourly space velocity (LHSV). O 2 conversion reaches a maximum (∼90.9%) at 333 K, NO/O 2 molar ratio of 6:1, EtOH/NO molar ratio of 3:1, N 2 volume fraction of 50%, and LHSV of 2.65 h −1 . The synthesis reaction is a fast one and takes place in a liquid film. A kinetics model based on the two-film model of gas–liquid reaction is proposed. The experiment data fit the kinetics model very well and statistical tests also show their reliability.

Topological analysis of the ELF and ELI-D functions has been carried out using DFT and CASSCF methods for cis- and trans-isomers of methyl nitrite (CH 3 ONO), as well as three conformers of ethyl nitrite (C 2 H 5 ONO). The N–O central bond is of protocovalent type and is represented by the V(N) and V(O) attractors (basins), with a population of 0.79/1.15e in CH 3 ONO and 1.08/1.12e in C 2 H 5 ONO. The correspondence between the protocovalent N–O bond and the most favourable dissociation channel, previously observed for nitrous acid (HONO) [9] , has been confirmed.

A method to maintain organ blood flow during laparoscopic surgery has not been developed. Here we determined if ethyl nitrite, an S-nitrosylating agent that would maintain nitric oxide bioactivity (the major regulator of tissue perfusion), might be an effective intervention to preserve physiologic status during prolonged pneumoperitoneum. The study was conducted on appropriately anesthetized adult swine; the period of pneumoperitoneum was 240 minutes. Cohorts consisted of an anesthesia control group and groups insufflated with CO2 alone or CO2 containing fixed amounts of ethyl nitrite (1-300 ppm). Insufflation with CO2 alone produced declines in splanchnic organ blood flows and it reduced circulating levels of S-nitrosohemoglobin (i.e., nitric oxide bioactivity); these reductions were obviated by ethyl nitrite. In a specific example, preservation of kidney blood flow with ethyl nitrite kept serum creatinine and blood urea nitrogen concentrations constant whereas in the CO2 alone group both increased as kidney blood flow declined. The data indicate ethyl nitrite can effectively attenuate insufflation-induced decreases in organ blood flow and nitric oxide bioactivity leading to reductions in markers of acute tissue injury. This simple intervention provides a method for controlling a major source of laparoscopic-related morbidity and mortality: tissue ischemia and altered postoperative organ function.

Ethyl and sodium nitrite were studied for their genetic toxicity in bacteria and barley. At physiological pH the organic nitrite had a greater mutagenic effectiveness than the inorganic nitrite. Concurrent treatments with ethyl nitrite and primary amines resulted in enhanced effects. The implication of these results in the genetic health hazards due to environmental pollution is discussed.

After taking alcoholic beverages, the ethanol is mixed with saliva and then gastric juice. As pH of gastric juice is around 2, the ethanol might be transformed to ethyl nitrite in the stomach by reacting with salivary nitrite. In this study, reactions between ethanol and nitrite in acidified saliva were investigated. The result indicates that nitrite in acidified saliva reacted with ethanol producing ethyl nitrite. It is discussed that ethyl nitrite might be formed in the stomach after drinking alcoholic beverages and that the ethyl nitrite might function as a donor of NO in intestinal and gastric tissues.

Rationale: Inhaled nitric oxide (NO) has been used to prevent bronchopulmonary dysplasia, but with variable results. Ethyl nitrite (ENO) forms S-nitrosothiols more readily than does NO, and resists higher-order nitrogen oxide formation. Because S-nitrosylation is a key pathway mediating many NO biological effects, treatment with inhaled ENO may better protect postnatal lung development from oxidative stress than NO.Objectives: To compare inhaled NO and ENO on hyperoxia-impaired postnatal lung development.Methods: We treated newborn rats beginning at birth to air or 95% O2 ± 0.2–20.0 ppm ENO for 8 days, or to 10 ppm NO for 8 days. Pups treated with the optimum ENO dose, 10 ppm, and pups treated with 10 ppm NO were recovered in room air for 6 more days.Measurements and Main Results: ENO and NO partly prevented 95% O2–induced airway neutrophil influx in lavage, but ENO had a greater effect than did NO in prevention of lung myeloperoxidase accumulation, and in expression of cytokine-induced neutrophil chemoat...

CO catalytic synthesis of diethyl carbonate in vapor phase had been studied in a continuous flow system and a fixed-bed reactor at atmospheric pressure. PdCl 2 –CuCl 2 /AC (activated carbon) catalyst exhibited better catalytic activity compared with other Wacker-type catalyst systems using SiO 2 , α-Al 2 O 3 and hexagonal mesoporous silica (HMS) as the carriers. The catalytic activity of the catalyst could be effectively improved by chemical pretreatment with H 2 . The suitable Pd content was 2.0 wt.% considering both factors of DEC production and DEC selectivity, and an optimum Pd/Cu mole ratio existed for catalytic activity, which was 1/2. The study also revealed that CH 3 OH was an excellent solvent for PdCl 2 –CuCl 2 /AC catalyst preparation.

From the inception of the Boston Medical and Surgical Journal in 1828 until the prominent public demonstration of surgical anesthesia on Ether Day of 1846, ether was often mentioned in the journal. Many of the examples were related to obstetrics. Because molecular structures were not available in the early 1800s, diverse volatile liquids were termed ethers. In addition to sulphuric ether, so-called ethers included cyanide-releasing propionitrile and ethanolic solutions of chloroform and of the potent vasodilator ethyl nitrite. Familiarity with anesthetically unsuitable ethers may have long deterred consideration of inhaled sulphuric ether for analgesia and anesthesia.

Photodissociation of gaseous nitroethane at 266 nm has been studied by monitoring the NO(X2Π) product using laser-induced fluorescence technique. Rotational state distributions of the NO(X2Π1/2 and X2Π3/2, v″ = 0) photofragment have been measured and characterized by Boltzmann temperature of 810 ± 100 K. Only the NO photoproduct in v″ = 0 state can be observed in the present work. The geometries of the nitroethane, the ethyl nitrite and the transition state connecting the two isomeric structures have been investigated using ab initio method. The photodissociation dynamics of nitroethane is discussed on the basis of experimental observation and calculation results.

A multistep mechanism has been elucidated for the reduction of NOx in the presence of added ethanol over Ag/γ-Al2O3 at 320 °C. Under these conditions, ethanol principally reacts with oxygen to form acetaldehyde. Surface acetate ions, which are formed from adsorbed acetaldehyde, react with NO2 to yield nitromethane. Evidence is presented indicating that the aci-anion of nitromethane is an intermediate. In contrast, NOx reduction with ethanol over Ag/γ-Al2O3 at 200 °C is inefficient, because surface acetate ions are much less reactive at 200 °C than at 320 °C. At 200 °C, the dominant pathway for ethanol oxidation is reaction with NO2, producing ethyl nitrite, which decomposes into a number of products, including N2O, which is stable under reaction conditions. On the basis of these mechanistic data, conditions can be defined under which NOx reduction with ethanol may be viable.

Monomethylhydrazine (MMH)/nitrogen tetroxide (NTO) is a well-known bipropellant combination system, the main advantage of which is low temperature ignition without ignition device, also called hypergolicity. The use of other chemical systems, less toxic, less hazardous, less corrosive, and more environmentally friendly than MMH/NTO are nowadays desirable. The replacement of the fuel MMH by ethanol (EtOH) is examined here. It is shown that ethanol/NTO mixtures are not hypergolic, but that reactions take place at room temperature and that these reactions form ethyl nitrite. Chemical reasons able to explain this reactivity, which does not lead to ignition, are discussed. In particular, it is shown that the EtOH/NTO initiation reactions going through H abstraction by NO2, whatever this initiation reaction is, and especially the one leading to ethyl nitrite, are considerably more endothermic than the corresponding MMH/NTO initiation reactions.

Studies of nitrosation of norbornene and norbornadiene derivatives and dimethyl tricyclo[4.2.2.02,5]deca-3,7-diene-9,10-cis-endo-dicarboxylate demonstrated that nitrosation of alkenes with EtONO-PHal3, EtONO-POHal3 (Hal = Cl or Br), and EtONO-SOCl2 systems can afford nitroso halides in high yields without the formation of by-products (ketones and oximes). The reactions with 5-substituted norbornenes are nonregioselective. The trans dimer of endo-5-trifluoromethyl-cis-exo-2-chloro-3-nitrosobicyclo[2.2.1]heptane was studied by X-ray diffraction.

The mechanism for the reaction of CO coupling to diethyl oxalate (DEO) over Pd–Fe/α-Al2O3 in gaseous phase at normal pressure was studied by X-ray photoelectron spectroscopy (XPS) and in situ diffuse reflectance infrared spectroscopy (DRIRS) techniques. The adsorption of two reactants, carbon monoxide and ethyl nitrite, on the catalyst was observed, respectively with in situ DRIRS as well as the catalysts after ethyl nitrite adsorption and after in situ reaction were also characterized by XPS measurement. These observational results show that (1) The ethyl nitrite on the catalyst surface has a dissociative chemisorption which leads to the oxidation of Pd0 to Pd2+ (active component on the catalyst). So the reaction is a redox process; (2) Two intermediates, palladium complexes, in the reaction process are involved. From this, the mechanism steps of the reaction were proposed and the two intermediates were inferred.

A vapor phase synthesis of diethyl carbonate (DEC) from carbon monoxide and ethyl nitrite (EN) was studied in a continuous flow micro fixed-bed reactor at atmospheric pressure. PdCl 2 –CuCl 2 /AC (activated carbon) catalyst exhibited better catalytic activity compared with other binary catalyst systems. The suitable Pd-loading is about 2.0 wt%, and some additives (LaCl 3 , CeCl 3 , PrCl 3 ) are benefit for the DEC yield and selectivity. Influences of various reaction parameters on the DEC yield and selectivity were tested. The optimum reaction temperature lies in 378–388 K and the suitable gas hourly space velocity (GHSV) range is 2500–3000 h −1 considering both factors of DEC production and CO conversion. An optimum CO/C 2 H 5 ONO mole ratio exists for catalytic activity, which is about 1/1. The stability of PdCl 2 –CuCl 2 /AC catalyst and PdCl 2 –CuCl 2 –CeCl 3 /AC catalyst was also investigated. The possible reason of the deactivation behavior of catalysts was discussed with the help of XRD.

The coupling reaction of carbon monoxide to diethyl oxalate in the presence of ethyl nitrite at atmospheric pressure over supported palladium catalyst was investigated in a continuous flow integral-type fixed-bed reactor with the aim of kinetic modeling and reactor performance studies. The effect of reaction conditions on the global rate and selectivity was studied. The main products formed were diethyl oxalate (DEO) and diethyl carbonate (DEC). The results at dp

The reaction kinetics of the catalytic coupling reaction of carbon monoxide to diethyl oxalate was studied in the presence of ethyl nitrite over supported palladium catalyst in gaseous phase at atmospheric pressure. The experiments were performed in a continuous flow fixed-bed differential type reactor. It was discovered that the rate-determining step is the surface reaction between adsorbed species and that ethyl nitrite dissociates into ethoxy radical (EtO−) and NO species and are adsorbed on two active sites. The kinetic model was proposed, with which some observations concerning with the reaction behaviors of the system can be readily accounted for. In the presence of hydrogen, the kinetics of the reaction system was also investigated. It was revealed that hydrogen, with adsorption and dissociation, reacts with adsorbed ethoxy radical to ethanol.

The mid-IR spectrum of gas-phase C2H5OO has been measured over the spectral range of 800−4000 cm-1. The employed experimental technique was long-path-length absorption in which a White cell was coupled to an FTIR spectrometer. Radicals were generated in a mixing manifold prior to the absorption cell by passing an F2/He mixture through a microwave discharge to create fluorine atoms followed by the reaction of atomic fluorine with an ethane/oxygen mixture. A number of absorption bands were observed to increase in intensity with increasing atomic fluorine concentration. Verification that the observed bands originated from the ethyl peroxy radical was done first by comparing measured band frequencies with the spectra of possible secondary reaction products and second by titrating C2H5OO• with excess nitric oxide and observing the nitrogen dioxide and ethyl nitrite products that ultimately result from the titration reaction. Bands were assigned to normal modes of C2H5OO• through comparing the observed band pos...

The synthesis of diethyl oxalate from ethyl nitrite and carbon monoxide in gaseous phase has been studied at atmospheric pressure. Kinetics of coupling - regeneration reaction has been determined and the optimization of the reaction has been simulated. The influences of gas impurities has also been studied. Scale-up circulating shows that the concentrate and selectivity were stable in the product and the process is suitable for industrial production.

Background. Nitric oxide ( ∙ NO), a ubiquitous molecule involved in a plethora of signaling pathways, is produced from dietary nitrate in the gut through the so-called nitrate–nitrite–NO pathway. In the stomach, nitrite derived from dietary nitrate triggers a network of chemical reactions targeting endogenous and exogenous biomolecules, thereby producing new compounds with physiological activity. Objective. The aim of this study was to ascertain whether compounds with physiological relevance are produced in the stomach upon consumption of nitrate- and ethanol-rich foods. Design. Human volunteers consumed a serving of lettuce (source of nitrate) and alcoholic beverages (source of ethanol). After 15 min, samples of the gastric headspace were collected and ethyl nitrite was identified by GC–MS. Wistar rats were used to study the impact of ethyl nitrite on gastric smooth muscle relaxation at physiological pH. Result. Nitrogen oxides, produced from nitrite in the stomach, induce nitrosation of ethanol from alcoholic beverages in the human stomach yielding ethyl nitrite. Ethyl nitrite, a potent vasodilator, is produced in vivo upon the consumption of lettuce with either red wine or whisky. Moreover, at physiological pH, ethyl nitrite induces gastric smooth muscle relaxation through a cGMP-dependent pathway. Overall, these results suggest that ethyl nitrite is produced in the gastric lumen and releases ∙ NO at physiological pH, which ultimately may have an impact on gastric motility. Systemic effects may also be expected if ethyl nitrite diffuses through the gastric mucosa reaching blood vessels, therefore operating as a ∙ NO carrier throughout the body. Conclusion. These data pinpoint posttranslational modifications as an underappreciated mechanism for the production of novel molecules with physiological impact locally in the gut and highlight the notion that diet may fuel compounds with the potential to modulate gastrointestinal welfare.

The annihilation of the most extended conformer on the comformational potential energy surface of ethyl nitrite is studied and analyzed in terms of the principles of stereoelectronic effects. The dynamic chirality of the prochiral CH 2 moiety in Me–CH 2 –ONO is investigated.

The synthesis of diethyl oxalate from ethyl nitrite and carbon monoxide was studied in a continuos flow micro fixed-bed reactor at atmospheric pressure. Two palladium catalysts supported on α-Al2O3 of different pore structures were studied under mild conditions. One catalyst (1 wt.% Pd/α-Al2O3-1) showed higher catalytic activity and selectivity than the other catalyst (1 wt.% Pd/α-Al2O3-2). X-ray diffraction patterns have confirmed that both supports are well-defined α-Al2O3. Palladium dispersions were greater on the 1 wt.% Pd/α-Al2O3-1 catalyst than that on the 1 wt.% Pd/α-Al2O3-2 catalyst as determined by hydrogen chemisorption. The FTIR spectroscopy study indicated that the 1 wt.% Pd/α-Al2O3-1 catalyst adsorbed CO easily in the linear form (band at 2089 cm−1) and bridge form (bands at 1950 and 1880 cm−1), and as carbonate species (at 1628 cm−1). There was little CO adsorption on 1 wt.% Pd/α-Al2O3-2. The average pore size of the support α-Al2O3-1 was 41.6 A, and 14.0 A for α-Al2O3-2. This study reveals that the pore structure of the supports remarkably affects the palladium dispersion of the catalysts and alters the CO adsorption behavior, therefore, dramatically affect the catalytic performance. In the case of CO+C2H5ONO reactions, diethyl oxalate was efficiently formed over the 1 wt.% Pd/α-Al2O3-1 catalyst.

The effect of hydrogen on catalytic coupling reaction of CO was tested at a temperature of 120 o C and residence time of 1.8 s. It was found that after introducing hydrogen to this system, ethanol was produced by H2 reaction with ethyl nitrite. With the increase of hydrogen concentration, the conversion of CO and H2 decreased and the selectivity of diethyl oxalate decreased too. The regeneration of the catalyst after removing hydrogen from the system was tested to prove reversible poisoning. The results show that the hydrogen concentration should be kept below 2 mol%.

Nitrosonium ethyl sulfate (1), which is generated in situ from ethyl nitrite and sulfur trioxide, is a convenient reagent for the one-pot transformation of olefins and dienes into substituted aldeh...

The microwave spectrum of ethyl nitrite (C2H5ONO) shows the presence of three rotational isomers, corresponding to cis–trans, cis–gauche, and trans–gauche structures. We have performed an investigation of the internal rotation of the methyl group in the cis–trans and cis–gauche rotamers and the motion of the ethyl group in the trans–gauche structure by using molecular beam-Fourier transform microwave (MB-FTMW) spectroscopy. Rotational spectra of these three isomers were recorded in the frequency regions 1–4 GHz and 7–26 GHz with two different spectrometers. For cis–trans ethyl nitrite we observed µa- and µb-type and for the cis–gauche form we detected µa-, µb-, and µc-type spectra. Due to the internal rotation of the methyl group, some lines were split and the torsional barriers could be determined, V3(CH3)=1082(2) cm-1 for the cis–trans and V3(CH3)=918(10) cm-1 for the cis–gauche form. For the trans–gauche form we found µa-, µb-, and µc-type spectra. The µb- and µc-type lines showed a doubling due to the interconversion between the two equivalent gauche conformers through rotation about the C–O axis. We determined the difference between the two lowest energy levels of the torsion around the C–O bond axis to be 68(3) kHz. Based on the observed splittings and the rotational constants, the Fourier coefficients of the potential hindering this internal rotation were determined to be V1=-1322 cm-1, V2=-1048 cm-1, V3=-412 cm-1, and V4=-109 cm-1 with a low barrier of 183(3) cm-1 in the trans position and a higher barrier of 1916(100) cm-1 in the cis position. Rotational, centrifugal distortion, and quadrupole coupling constants and some structural parameters have also been obtained from the analysis of spectra.

Ab initio and density functional (DFT) methods were used to investigate the rotamers of ethyl nitrite. The potential energy surface for rotations around the C-O and the N-O bonds was calculated at different levels of theory. From the four geometrically possible conformers, only three were found to be stable when correlation effects are taken into account in the calculations. This result is consistent with a microwave study of Turner (J. Chem. Soc., Faraday Trans. 2 1979, 317.) as well as with the presented IR spectrum of matrix-isolated ethyl nitrite which clearly distinguishes three different N dO stretching modes. A simulated IR spectrum generated from the results of the DFT calculations is in good agreement with this matrix spectrum and allows us to tentatively assign groups of frequencies.

Inhaled nitric oxide is used to alleviate pulmonary hypertension and hypoxaemia, but generates toxic free radicals and oxides of nitrogen (NO(x)), which can cause rebound-hypoxia and additional pulmonary and other morbidity. To address these problems, we assessed the efficacy of inhaled O-nitrosoethanol gas (ENO) as a novel alternative means of providing nitric oxide bioactivity in the treatment of persistent pulmonary hypertension of newborns. We administered ENO over 4 h to seven neonates who required assisted ventilation, and who had an oxygenation index of 25 or more. ENO was then shut off for 15 min before start of treatment with inhaled nitric oxide. Our results show that ENO produced sustained improvements in postductal arterial oxygenation and systemic haemodynamics, which were maintained during the off-drug observation period. Increases in methaemoglobinaemia were modest and toxic NO(x) were not detected. Thus, ENO can improve oxygenation and systemic haemodynamics in neonates, and seems to reduce rebound hypoxaemia and production of toxic byproducts.

Although both organic and inorganic nitrates/nitrites mediate their principal effects via nitric oxide, there are many important differences. Inorganic nitrate and nitrite have simple ionic structures and are produced endogenously and are present in the diet, whereas their organic counterparts are far more complex, and, with the exception of ethyl nitrite, are all medicinally synthesised products. These chemical differences underlie the differences in pharmacokinetic properties allowing for different modalities of administration, particularly of organic nitrates, due to the differences in their bioavailability and metabolic profiles. Whilst the enterosalivary circulation is a key pathway for orally ingested inorganic nitrate, preventing an abrupt effect or toxic levels of nitrite and prolonging the effects, this is not used by organic nitrates. The pharmacodynamic differences are even greater; while organic nitrates have potent acute effects causing vasodilation, inorganic nitrite's effects are more subtle and dependent on certain conditions. However, in chronic use, organic nitrates are considerably limited by the development of tolerance and endothelial dysfunction, whereas inorganic nitrate/nitrite may compensate for diminished endothelial function, and tolerance has not been reported. Also, while inorganic nitrate/nitrite has important cytoprotective effects against ischaemia-reperfusion injury, continuous use of organic nitrates may increase injury. While there are concerns that inorganic nitrate/nitrite may induce carcinogenesis, direct evidence of this in humans is lacking. While organic nitrates may continue to dominate the therapeutic arena, this may well change with the increasing recognition of their limitations, and ongoing discovery of beneficial effects and specific advantages of inorganic nitrate/nitrite.

1,4-Diaryl-1-aza-1, 3-butadienes (I) undergo a stereospecific 1,4-cycloaddition reaction with aryl sulphonyl nitrosites (II) generated ‘in situ’ by the reaction of aryl sulphinic acid and ethyl nitrite to yield six-membered cycloadducts characterized as 2-aryl sulphonyl-3, 6-diaryl-2H, 3H, 6H-[1, 2, 3] oxadiazine derivatives (III) in good yield.

Nitrosonium ethyl sulfate (1), which is generated in situ from ethyl nitrite and sulfur trioxide, is a convenient reagent for the one-pot transformation of olefins and dienes into substituted aldeh...

Reactions of salivary nitrite with components of wine were studied using an acidic mixture of saliva and wine. The formation of nitric oxide (NO) in the stomach after drinking wine was observed. The formation of NO was also observed in the mixture (pH 3.6) of saliva and wine, which was prepared by washing the oral cavity with wine. A part of the NO formation in the stomach and the oral cavity was due to the reduction of salivary nitrite by caffeic and ferulic acids present in wine. Ethyl nitrite produced by the reaction of salivary nitrite and ethyl alcohol in wine also contributed to the formation of NO. In addition to the above reactions, caffeic acid in wine could be transformed to the oxathiolone derivative, which might have pharmacological functions. The results obtained in this study may help in understanding the effects of drinking wine on human health.

The pathway by which inhaled NO gas enters pulmonary alveolar epithelial cells has not been directly tested. Although the expected mechanism is diffusion, another route is the formation of S-nitroso-L-cysteine, which then enters the cell through the L-type amino acid transporter (LAT). To determine if NO gas also enters alveolar epithelium this way, we exposed alveolar epithelial-rat type I, type II, L2, R3/1, and human A549-cells to NO gas at the air liquid interface in the presence of L- and D-cysteine+/-LAT competitors. NO gas exposure concentration dependently increased intracellular NO and S-nitrosothiol levels in the presence of L- but not D-cysteine, which was inhibited by LAT competitors, and was inversely proportional to diffusion distance. The effect of L-cysteine on NO uptake was also concentration dependent. Without preincubation with L-cysteine, NO uptake was significantly reduced. We found similar effects using ethyl nitrite gas in place of NO. Exposure to either gas induced activation of soluble guanylyl cylase in a parallel manner, consistent with LAT dependence. We conclude that NO gas uptake by alveolar epithelium achieves NO-based signaling predominantly by forming extracellular S-nitroso-L-cysteine that is taken up through LAT, rather than by diffusion. Augmenting extracellular S-nitroso-L-cysteine formation may augment pharmacological actions of inhaled NO gas.