Reactions Of Aromatic Compounds Research Articles

Reaction of Aromatic Compounds with Palladium(II) Salts Acetoxylation of Nucleus, Oxidation of Side Chain and Oxidative Coupling

酢酸溶媒申,硝酸パラジウム(II)と芳香族化合物の反応により,(1)芳香核のアセトキシル化,(2)側鎖メチル基の酸化,(3)芳香核の酸化的縮合,が起こった。主反応は(1)であったが,水,過旛素酸,硫酸鉄などを加えると(3)が主反応となり,塩素イオンを存在させるといずれの反応もほとんど起こらなかった。酢酸パラジウム(II)や硫酸パラジウム(II)を用いると(3)が主反応となった.核アセトキシル化反応は,パラジウム(II)塩と芳香族化合物の単核のπ型錯体における脱水素一アセトキシル化を経て進み,核の酸化的縮合反応はその複核錯体を通って起こるものと結論した。副反応としてニトロ化が起こったが,通常のニトロ化とは異なりトルエンからm-体がもっとも多く生成した。この反応もパラジウムと芳香族のπ錯体を通って進むものと思われる.

Electrophilic aromatic substitution. Part II. The nitration of some reactive aromatic compounds by nitric acid in sulpholan and nitromethane

The nitration in sulpholan, and to a lesser extent in nitromethane, of a number of aromatic compounds has been studied. In sulpholan zeroth-order, mixed-order, and first-order kinetics were observed with mesitylene, toluene, and benzene, respectively. A comparison is made of sulpholan with nitromethane and acetic acid, other solvents in which zeroth-order nitration has been observed.By adding water to sulpholan and to nitromethane it was possible to produce media in which all the compounds examined were nitrated according to the first-order law; rates relative to that of benzene were established. The relative rate of nitration of mesitylene in sulpholan, established by the competitive method, was the same as that in 7·5% aqueous sulpholan, established by the kinetic method.In both 7·5% aqueous sulpholan and 15% aqueous nitromethane a limit to the rate of nitration is reached which is about 300 times the rate for benzene under the same conditions. Thus, m-xylene and more reactive compounds are all nitrated at about the same rate, which is the rate of encounter of the nitronium ions and the aromatic molecules. The factors which determine the point in a series of aromatic compounds at which control of rate by encounter sets in are discussed.It is shown that a very reactive compound such as anthanthrene is extremely susceptible to nitration through nitrosation, though under appropriate conditions nitration according to the zeroth-order law could with difficulty be observed. Thus, nitration by nitronium ion and through nitrosation have both been observed. These results, combined with the establishment for organic media of a limiting rate of nitration set by encounter control, make it probable that the very high substrate selectivities reported by other authors for nitration of very reactive compounds in acetic anhydride refer, in fact, to nitration through nitrosation.

Electrophilic aromatic substitution. Part I. The nitration of some reactive aromatic compounds in concentrated sulphuric and perchloric acids

The nitration of benzene and some more reactive compounds in sulphuric acid (and to a smaller extent in perchloric acid) has been studied. In both media a limit is reached beyond which the introduction of further activating substituents does not increase the rate of nitration. This limit is the rate of encounter of the nitronium ions and the aromatic molecules. Up to 68% sulphuric acid the slope of the plot of the stoicheiometric second-order rate constant for the nitration of benzene against –(HR+ log aH2O) at 25° is unity, but above this acidity the slope increases. These facts diminish the value of a comparison of the rate of nitration of a given substrate with that of benzene as a means of studying aromatic reactivity, for the comparison would be dependent on the acidity. Further, at the higher end of the acidity range studied, the rate of nitration of benzene approaches to within a sixth of the observed encounter rate, and if the former is then to some degree encounter-controlled, the significance of comparison with other substrates is reduced.

Reactions of Aromatic Compounds in Liquid Ammonia.

Reactions of Aromatic Compounds in Liquid Ammonia.

The Reactivity of Aromatic Compounds toward Hydroxyl Radicals

The Reactivity of Aromatic Compounds toward Hydroxyl Radicals

Reactivity of Aromatic Compounds towards Hydrogen Atoms

THE reactivity of aromatic compounds toward hydrated electrons and hydroxyl radicals has been the subject of various recent investigations1,2. The effects of substituents on the reactivities of benzene and benzoate ion were correlated with the substituent constant (σ) of Hammett's equation. It has been shown that the mechanism of attack of hydroxyl radicals on aromatic compounds is analogous to electrophilic aromatic substitution2. On the other hand, the reactions of hydrated electrons followed a pattern analogous to nucleophilic substitution. The reactivity of aromatic compounds toward hydrogen atoms was investigated in order to study the nature of the PhX + H reaction.

Progress in the Reactions of Aromatic Compounds.

Progress in the Reactions of Aromatic Compounds.

Cyclopropenylium Compounds and Cyclopropenones

AbstractThe predictions of Hückel's rule gave the incentive to numerous investigations which led ultimately to a new definition of aromatic character, and which have added greatly to our knowledge of the properties and reactivity of aromatic compounds. Increasing use was made of physical measurements as criteria for the aromaticity of a compound. The first member (n = O) in the series of Hückel's (4n + 2) π systems is the cyclopropenylium cation. The predictions regarding the stability of this system have been confirmed at least qualitatively by the synthesis of cyclopropenylium salts. Properties and reactions of cyclopropenylium compounds and cyclopropenones were investigated.

Kinetics and reactivity of aromatic compounds in halogenation over metal halides: Halogenation of benzene over chlorides of aluminum, tin, and titanium

In the view of long-term water sustainability and worldwide problems of environmental pollution, new and novel scientific studies on modern technologies and advance scientific processes, deep understanding of the mechanistic aspects of the processes and the circumstances affecting it, exhaustive research on the photocatalyst based wastewater treatment hold a great promise. Over the last decade, photon-mediated titanium dioxide, photo-Fenton processes, and their modifications have been widely investigated as an efficient, robust, and attractive photocatalytic system for wastewater treatment, however, the correlation between TiO2 based composites, treatment processes and photocatalytic performances remains still under debate. This review provides an overview of the development of TiO2 based photocatalytic systems and new functionalized photocatalysts, their kinetic studies, and role of scavengers related to the advance and modified processes in wastewater treatment. Furthermore, the treatment of real wastewater in industrial sector and the futuristic cost-effective alternative with high catalytic capacity have also been delineated.

Notes. Are Organic Group Influences Additive in All Reactions of Aromatic Compounds?

Notes. Are Organic Group Influences Additive in All Reactions of Aromatic Compounds?

Reaction of Aromatic Compounds with a Chlorinated Coal and Aluminium Chloride

VAN KREVELEN et al. 1 have reported on the coupling of pitch molecules by chloromethylation and subsequent condensation under the influence of a Friedel-Crafts catalyst, while Iyengar, Banerjee and Banerjee2 have claimed the alkylation of coals with benzyl chloride and aluminium chloride. But in these laboratories a similar type of reaction between a chlorinated low-rank coal (containing about 50 per cent of hydrolysable chlorine) and several aromatic compounds, in the presence of aluminium chloride, has given inconclusive results which suggest that alkylation may not have occurred during the reaction with benzyl chloride.

On the theory of aromatic substitution: I. A theoretical treatment of the effect of poles and dipoles on the substitution type

AbstractThe method previously described This is the second of a series of communications on the influence of substituents on the reactivity of aromatic compounds. For the first communication cf: F. L. J. Sixma, J. Chem. Phys. 19, 1209 (1951). for calculating the influence of the electric field of a substituent (inductive effect) on the energy content of the intermediate complex of substitution reactions in the benzene nucleus, proceeding from the known values of dipole moments, bond lengths and valency angles, is further elaborated.The theory is tested on the experimental results for electrophilic substitution reactions. The agreement between calculated and experimental values for the percentage meta‐substitution is very satisfactory for those substituents which show little or no resonance interaction (E‐effect) with the pentadienate cation.

N-Nitration and C-Nitration by the Nitronium Ion

AROMATIC C-nitration through attack by the nitronium ion was kinetically established by the work of Benford and Ingold1, and of Hughes, Ingold and Reed2. The central point in the evidence was the observation of zeroth-order kinetics in the nitration of suitably reactive aromatic compounds, for example, of toluene, by a constant excess of nitric acid, in organic solvents such as nitromethane or acetic acid. All those aromatic compounds which are sufficiently reactive to take up the nitronium ion as fast as it is formed from nitric acid obey this law, and, for the same medium and temperature, can be observed to become nitrated at an identical rate, which is simply the rate of formation of the nitronium ion.

353. Kationoid reactivity of aromatic compounds. Part VIII. The action of fused potassium hydroxide on 6 : 6′-dimesobenzanthronyl and a note on the properties of 6- and 8-chloromesobenzanthrones

353. Kationoid reactivity of aromatic compounds. Part VIII. The action of fused potassium hydroxide on 6 : 6′-dimesobenzanthronyl and a note on the properties of 6- and 8-chloromesobenzanthrones

232. Kationoid reactivity of aromatic compounds. Part VI. The direct amination of mesobenzanthrone

232. Kationoid reactivity of aromatic compounds. Part VI. The direct amination of mesobenzanthrone

Kationoid reactivity of aromatic compounds; the composition of the dimesobenzanthronyl formed by the action of alkaline condensing agents of mesobenzanthrone.

Kationoid reactivity of aromatic compounds; the composition of the dimesobenzanthronyl formed by the action of alkaline condensing agents of mesobenzanthrone.

375. Kationoid reactivity of aromatic compounds. Part IV. Hydroxylation of mesobenzanthrone

375. Kationoid reactivity of aromatic compounds. Part IV. Hydroxylation of mesobenzanthrone