The gaseous oxidation of tertiary aliphatic amines II. Trimethylamine

1958 ◽  
Vol 246 (1244) ◽  
pp. 91-98 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Oxides ◽  
Major Part ◽  
Aliphatic Amines ◽  
Inert Gas ◽  
Primary Amines ◽  
Present System ◽  
Peroxy Radicals ◽  
Heterogeneous Process ◽  
Powerful Effect

A study of the slow oxidation of trimethylamine shows that the reaction has no autocatalytic character and rapidly becomes inhibited as the products accumulate, eventually ceasing completely while the major part of the initial reactants remains unchanged. Both the rate and extent of oxidation are reduced by increased surface but additions of an inert gas have no influence on the reaction. The main stable products are formaldehyde and dimethylamine together with smaller amounts of nitrogen and carbon monoxide; neither methylamine nor ammonia nor nitrogen oxides can be detected at any stage of reaction. Separate experiments on the influence of additives show that dimethylamine, although it acts as an inhibitor, does not exert a sufficiently powerful effect to account for the observed results, and it is clear that some other compound with more pronounced inhibiting properties must also be formed in small quantities. It is suggested that NN -dimethylhydroxylamine, which is an exceptionally powerful inhibitor, may be formed either by oxidation of (CH 3 ) 2 N. radicals or by some heterogeneous process. The absence in the present system of primary amines, which are among the principal products of triethylamine oxidation, may be due to the fact that for steric reasons intramolecular attack of intermediate peroxy-radicals derived from trimethylamine cannot take place.

The thermal oxidation of methylamine

1951 ◽  
Vol 209 (1097) ◽  
pp. 218-238 ◽  
Keyword(s):  
Carbon Monoxide ◽  
Reaction Mechanism ◽  
Nitrogen Oxides ◽  
Major Part ◽  
Close Agreement ◽  
Inert Gases ◽  
Rate Of Reaction ◽  
Secondary Reactions ◽  
Kinetics Of ◽  
Oxidation Analysis

A study has been made of the kinetics of the reaction of gaseous methylamine with oxygen. Since the nitrogen atom is eliminated from the molecule in the course of the oxidation, analysis of the products formed at various stages yields evidence about the reaction mechanism which is not available in the study of hydrocarbons. The variation of oxidation rate with time may be represented by the equation dp / dt ═ B e ct + D , and the influence of reactant pressures and of temperature on C and D has been determined. Inert gases do not affect the course of the oxidation, but an increase in surface inhibits the reaction to an extent dependent on the composition of the reactant mixture. Since the later stages of the oxidation are complicated by secondary reactions, the analytical results for the early stages provide the most useful information about the main chemical reactions occurring. The greater part of the combined nitrogen is initially converted to ammonia, but small quantities of nitrogen oxides are also formed. The fact that the concentration of ammonia is lowered and that of nitrogen oxides is raised by increasing oxygen pressure suggests that both products arise from reaction of NH 2 radicals with the original reactants. One source of these radicals is probably the breakdown of intermediate peroxides such as NH 2 CH 2 —O—O—H, the concentration of which largely controls the rate of reaction. Such a decomposition should give rise to formaldehyde and ammonia in approximately equal amounts. The non-equivalence of these products suggests, however, that the major part of the ammonia is formed in some other way, and it is supposed that peroxide radicals such as NH 2 CH 2 —O—O— may, instead of reacting with methylamine to give the peroxide as usually postulated, themselves decompose unimolecularly to give ammonia and carbon monoxide. An attempt is made to construct a simplified theory of the oxidation, to estimate the relative frequencies of some of the proposed reaction stages and hence to calculate certain ratios of velocity constants. The suggested mechanism leads to kinetic relationships in close agreement with those found experimentally.

The oxidation of iso butene catalyzed by hydrogen bromide

1962 ◽  
Vol 268 (1334) ◽  
pp. 405-423 ◽  
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Double Bond ◽  
Small Proportion ◽  
Main Chain ◽  
Hydrogen Bromide ◽  
Inert Gas ◽  
Static System ◽  
Peroxy Radicals ◽  
Methyl Group

The oxidation of iso butene catalyzed by hydrogen bromide in a static system between 100 and 200 °C has been investigated. In a boric oxide coated vessel below about 170 °C the pressure decreased continually during the reaction, the rate accelerating rapidly to a maximum and then falling gradually and the main products being BrCH 2 .C(CH 3 ) 2 .OOH and a diperoxide. The reaction ceased after only a small proportion of the olefin was oxidized owing to the HBr being used up. At 145 °C ρ max. ∝ [C 4 H 8 ] 0.35 [O 2 ] 0.5 [HBr] 1.76 . Added inert gas or packing the vessel had little effect on the rate, but the reaction was accelerated by added bromine, t .-butyl hydroperoxide and di- t .-butylperoxide and retarded by added alcohols. At 195 °C the pressure decreased to a minimum and then rose, most of the iso butene being now oxidized and other products, CH 2 =C(CH 3 )CH 2 OOH, methacrolein, acetone, carbon monoxide, carbon dioxide and water being formed in appreciable yields. It is suggested that autocatalysis is due to the reaction of a small proportion of the hydroperoxides produced with HBr to give radicals, and that the main chain carriers are bromine atoms and peroxy radicals, the former either adding to the double bond of the olefin or at the higher temperatures abstracting hydrogen from a methyl group and the latter abstracting hydrogen from HBr to give the hydroperoxides, adding to the double bond of iso butene to give eventually diperoxides or at the higher temperatures decomposing.

Efficient Copper-Catalysed Synthesis of Carbazoles by Double N-Arylation of Primary Amines with 2,2′-Dibromobiphenyl in the Presence of Air

Synlett ◽  
2021 ◽  
Author(s):  
Tran Quang Hung ◽  
Tuan Thanh Dang ◽  
Peter Langer ◽  
Ha Nam Do ◽  
Nguyen Minh Quan ◽  
...  
Keyword(s):  
Aromatic Amines ◽  
Aliphatic Amines ◽  
Primary Amines ◽  
Coupling Reactions ◽  
Carbazole Derivatives ◽  
High Yields

AbstractAn efficient Cu-catalyzed synthesis of carbazole derivatives is reported, which proceeds by double C–N coupling reactions of 2,2′-dibromobiphenyl and amines in the presence of air. The reaction is robust, proceeds in high yields, and tolerates a series of amines including neutral, electron-rich, electron-deficient aromatic amines and aliphatic amines.

OPTIMIZATION OF GAS-DIESEL ENGINE REGULATION AS A METHOD OF IMPROVING ITS ECOLOGICAL CHARACTERISTICS

2021 ◽  
pp. 28-32
Author(s):  
VALERIY L. CHUMAKOV ◽  
Keyword(s):  
Carbon Monoxide ◽  
Diesel Engine ◽  
Nitrogen Oxides ◽  
Diesel Fuel ◽  
Hydrocarbon Fuel ◽  
Load Range ◽  
Engine Operation ◽  
Exhaust Gases ◽  
Wide Range ◽  
Diesel Cycle

The paper shows some ways to improve the environmental characteristics of a diesel engine using gaseous hydrocarbon fuel and operating the engine in a gas-diesel cycle mode. Some possibilities to reduce toxic components of exhaust gases in a gas-diesel engine operating on liquefi ed propane-butane mixtures have been studied. Experiments carried out in a wide range of load from 10 to 100% and speed from 1400 to 2000 rpm showed that the gas-diesel engine provides a suffi ciently high level of diesel fuel replacement with gas hydrocarbon fuel. The authors indicate some eff ective ways to reduce the toxicity of exhaust gases. The engine power should be adjusted by the simultaneous supply of fuel, gas and throttling the air charge in the intake manifold. This method enriches the fi rst combusting portions to reduce nitrogen oxides and maintains the depletion of the main charge within the fl ammability limits of the gas-air charge to reduce carbon monoxide and hydrocarbons. The authors found that when the engine operates in a gas-diesel cycle mode, the power change provides a decrease in nitrogen oxide emissions of gas-diesel fuel only due to gas supply in almost the entire load range as compared to the pure diesel. At high loads (more than 80%) stable engine operation is ensured up to 90% of diesel fuel replaced by gas. Even at 10% of diesel fuel used the concentration of nitrogen oxides decreases by at least 15…20% as compared with a diesel engine in the entire load range. However, there is an increased emission of hydrocarbons and carbon monoxide in the exhaust gases. Further experimental studies have shown that optimization of the gas diesel regulation can reduce the mass emission of nitrogen oxides contained in exhaust gases in 2…3 times and greatly reduce the emission of incomplete combustion products – carbon monoxide and hydrocarbons.

scholarly journals The study on decreasing of nitrogen oxides emission carried out on DKVR 10-13 industrial heating boilers

2018 ◽  
Vol 44 ◽  
pp. 00056 ◽  
Author(s):  
Sylwia Janta-Lipińska ◽  
Alexander Shkarovskiy
Keyword(s):  
Carbon Monoxide ◽  
Nitrogen Oxides ◽  
Experimental Studies ◽  
Steam Injection ◽  
Reference Level ◽  
Optimal Parameters ◽  
End Caps ◽  
Atmosphere Pollution ◽  
Industrial Heating ◽  
Study Plan

Nitrogen oxides are considered to be much more toxic than, for example, carbon monoxide. For this reason, the Authors developed and implemented a method for decrease of NOX emission into the atmosphere from DKVR 10-13 boilers. As an effective method for boilers propose injection of steam into the combustion zone. After series of experimental studies an optimal design of the head for steam injection was developed, according to the proprietary technology. The injector head was kept unchanged while the spraying end caps were modified (Fig. 2). Three levels of possible impact of emissions from boiler on the atmosphere pollution were taken into account during studies. After the analysis, it was assumed that the level of the real maximum emission should be taken as the reference level in relation to which the decrease of NOX emission should be determined. The results obtained by the Authors calculated into mass emission and as objective values of nitrogen oxides concentration calculated into α = 1 (Figures 3 and 4). Realization of the study plan, assumed by the Authors, allowed to determine the optimal parameters of the NOx emission decrease method, assuming the expected 30% level of emission decrease at a limited consumption of injected.

ChemInform Abstract: The “Benzostabase” Protecting Group for Primary Amines. Application to Aliphatic Amines.

ChemInform ◽  
2010 ◽  
Vol 23 (15) ◽  
pp. no-no
Author(s):  
R. P. BONAR-LAW ◽  
A. P. DAVIS ◽  
B. J. DORGAN ◽  
M. T. REETZ ◽  
A. WEHRSIG
Keyword(s):  
Aliphatic Amines ◽  
Primary Amines ◽  
Protecting Group

Molekülinterne Dipolorientierung und dielektrische Absorption in verdünnter Lösung bei Mikro- und Submillimeter-Wellen. I. Primäre Amine / Intramolecular Dipole Reorientation and Dielectric Loss of Microwaves and, Submillimetrewaves in Diluted Solution I. Primary Amines

1982 ◽  
Vol 37 (2) ◽  
pp. 102-112
Author(s):  
G. Klages ◽  
E. Wieczorek
Keyword(s):  
Dipole Moment ◽  
Dielectric Loss ◽  
High Frequency ◽  
Aliphatic Amines ◽  
Primary Amines ◽  
High Frequency Region ◽  
Debye Relaxation ◽  
Diluted Solution ◽  
Wave Region ◽  
Molecular Resonances

Abstract The dielectric loss of very diluted solutions of four aromatic and three aliphatic amines in three non polar aliphatic solvents at 20 °C has been measured. The wave numbers cover 0.1 to 200 cm-1 . It is shown, how to analyse the microwave spectra of the loss factor ε″ in terms of three absorption areas, two of Debye relaxation type and the high frequency one of Lorentz resonance type. To limit the latter at its high frequency side, the extinction coefficient a has been used to determine and separate the lowest molecular resonances. From the analysis, dispersion steps and the components of the dipole moment due to the three absorption regions are calculated. Comparison with the so called optical dispersion step insures within the limits of experimental error that the absorption due to orientation of the permanent dipole moment is covered by the measured band. The long wave region belongs to the rotation of the molecules, the two others to intramolecular reorientation. In aromatic amines not all molecules of the sample are able to invert their NH2 group, but slower orientation by hindered inversion happens. On the other hand, in aliphatic amines the group is rotating and the high frequency region may be due to Foley absorption.

Photolysis of ketene. I

1968 ◽  
Vol 46 (14) ◽  
pp. 2353-2360 ◽  
Author(s):  
A. N. Strachan ◽  
D. E. Thornton
Keyword(s):  
Carbon Monoxide ◽  
Quantum Yield ◽  
Triplet State ◽  
Singlet State ◽  
Inert Gases ◽  
Inert Gas ◽  
Excited Singlet State ◽  
Intersystem Crossing ◽  
Excited Singlet ◽  
Increasing Temperature

Ketene has been photolyzed at 3660 and 3130 Å both alone and in the presence of the inert gases C4F8 and SF6. The quantum yield of carbon monoxide has been determined at both wavelengths as a function of pressure and temperature. At 3660 Å the quantum yield decreases with increasing pressure but increases with increasing temperature. At 3130 Å the quantum yield with ketene alone remains 2.0 at both 37 and 100 °C at pressures up to 250 mm. At higher pressures of ketene or with added inert gas the quantum yield decreases with increasing pressure. The results are interpreted in terms of a mechanism in which intersystem crossing from the excited singlet state to the triplet state occurs at both wavelengths, and collisional deactivation of the excited singlet state by ketene is single stage at 3660 Å but multistage at 3130 Å.

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