Reactions Of Aromatic Compounds Research Articles

Inhibition of Hydroxyl Radical Reaction with Aromatics by Dissolved Natural Organic Matter

Reaction of aromatic compounds with hydroxyl radical is inhibited by dissolved natural organic matter (NOM). The degree of inhibition is significantly greater than that expected based on a simple model in which aromatic compound molecules bound to NOM are considered to be unreactive. In this study, hydroxyl radical was produced at steady-state concentrations using Fenton chemistry (H2O2 + Fe2+ → Fe3+ + HO- + HO·). Suwannee River fulvic acid and humic acid were used as NOM. The most likely mechanism for the observed inhibition is that hydroxyl radical formation occurs in microenvironmental sites remote from the aromatic compounds. In addition to changes in kinetics, pyrene hydroxyl radical reaction also exhibited a mechanistic change in the presence of fulvic acid. The mechanism changed from a reaction that was apparently first-order in pyrene to one that was apparently second-order in pyrene, indicating that pyrene self-reaction may have become the dominant mechanism in the presence of fulvic acid. Dissol...

Reactivity of aromatic compounds toward diphenylcarbonyl oxide

The reactivity of organic compounds (PhH, PhMe, PhF, PhCl, PhOH, PhOEt, PhCHO, Ph2CO, PhCN, Ph2S, Ph2SO, Ph2SO2, andp-Me2C6H4) toward diphenylcarbonyl oxide Ph2COO was characterized by thek33/k31 ratio, wherek33 andk31 are the rate constants for the reactions of Ph2COO with the arene and diphenyldiazomethane Ph2CN2, respectively. The values ofk33/k31 vary from 2.6·10−3 (PhCN) to 0.65 (Ph2S) (70°C, MeCN). The reaction is preceded by formation of a complex with charge transfer from a substrate to Ph2COO. In the reactions with aromatic substances (except for Ph2SO, PhCHO, and Ph2CO), carbonyl oxide behaves as an electrophile.

Functional selectivity in Friedel–Crafts alkylations with allylic halides promoted by solid composite lead fluoride reagent

The composite lead fluoride reagent prepared from PbF2 and NaBr is a nonhygroscopic and efficient solid reagent for promoting Friedel–Crafts type reaction of aromatic compounds with allylic halides selectively to afford the monoallylated compounds.

Flash photolysis study of a Friedel–Crafts alkylation. Reaction of the photogenerated 9-fluorenyl cation with aromatic compounds

A combination of flash photolysis and product analysis is employed to investigate the reaction of aromatic compounds (ArH) with the 9-fluorenyl cation (Fl+) photogenerated from 9-fluorenol in 1,1,1,3,3,3-hexafluoroisopropyl alcohol (HFIP). The availability of the photochemical route to Fl+ means that the reaction of a benzylic-type cation with ArH can be directly followed by flash photolysis. An additional feature with electron-rich ArH is that the cyclohexadienyl cation is observed to grow as Fl+ decays. Thus both cationic intermediates of a Friedel–Crafts alkylation are observed in the same experiment. The formation of the cyclohexadienyl cation is demonstrated to be reversible, or at least quasi-reversible, with the kinetic analysis furnishing absolute rate constants for the formation of this cation, as well as for its loss of H+ and Fl+. Values of kH:kD for benzene: [2H6]benzene and toluene: [2H8]toluene are ∼ 1.5 and demonstrate that Fl+ addition is at least partly reversible with these compounds as well. The Hammett ρ+ value obtained for a series of the less electron-rich ArH is –8, indicative of a transition state with considerable cyclohexadienyl cation character. Anisole shows a negative deviation from the Hammett correlation line, explained by the addition of Fl+ to ArH becoming encounter-controlled. This behaviour is dramatically illustrated in a comparison of data for Fl+ and Br2. For the less electron-rich ArH, rate constants for the two electrophiles are parallel. However, from m-xylene through pentamethylbenzene, the rate with Fl+ is unchanged, while the rate with Br2 increases over 1000-fold. The concept of encounter control with Fl+ is strongly supported by the absolute rate constants, which for the the electron-rich ArH are all in the range 1–2 × 109 dm3 mol–1 s–1, a magnitude typical of diffusion-controlled reactions. The electron-rich ArH also show no intermolecular selectivity since their reactions are encounter-controlled, but have a high intramolecular selectivity. It is suggested that a factor influencing the latter is the reversibility of formation of the cyclohexadienyl cation from the encounter complex.

Persistent radical cation solutions from the reaction between aromatics and bromine, chlorine or iodine chloride in 1,1,1,3,3,3-hexafluoropropan-2-ol at room temperature

The treatment of reactive aromatic compounds by bromine, chlorine or iodine chloride in 1,1,1,3,3,3-hexafluoropropan-2-ol gives persistent solutions of the corresponding radical cations, in spite of the fact that a nucleophile, a chloride or bromide ion, is simultaneously generated.

Aluminium Chloride Promoted Carbohydroximoylation Reaction of Aromatic Compounds with Primary Nitroalkanes

Abstract The reaction of primary nitroalkanes with aromatic compounds in the presence of aluminium chloride afforded the corresponding carbohydroximoylated aromatic compounds.

Direct allylation of aromatic compounds with allylic chloride using the supported reagents system ZnCl2/SiO2–K2CO3/Al2O3

Although the reaction of aromatic compounds with allylic chlorides using ZnCl2/SiO2 gives 2-chloro-1-arylalkanes accompanied with diarylalkanes, similar reaction using ZnCl2/SiO2–K2CO3/Al2O3 produces the monoallylated compound as the major product in good yield.

Mechanisms of aromatic lithiation: Influence of aggregation and directing groups

High level ab initio calculations (MP2(fc)/6-31+ G*/MP2(fc)6-31G*Δ+ZPE/6-31IG* show that the reaction of aromatic compounds with methyllithium is not an electrophilic substitution, but a hydrogen transfer along an almost linear path, with the (coordinatively highly unsaturated) “active” lithium cation bridging the methyl carbanion and the carbon atom being lithiated. Aggregation (modelled with lithium hydride) does not change the mechanism. However, intra-aggregate bonding stabilizes the “active” lithium ( i.e., the one directly undergoing transfer). The mixed dimer of methyllithium and lithium hydride is predicted to be more reactive than methyllithium monomer in the lithiation of benzene, due to interaction of the “passive” lithium with the aromatic π-system and the carbon atom being lithiated. The accelerating and ortho-directing effect of Lewis base substituents is due to stabilization of the “active” lithium in the transition state by intramolecular coordination and favorable electrostatic interactions. These stabilizing effects are strongest for reaction of a monomer, but are also significant in the reaction of anisole with the mixed dimer of methyllithium and lithium hydride.

ChemInform Abstract: Thioalkylation of Reactive Aromatic Compounds with α‐( Benzotriazol‐1‐yl)benzyl Phenyl Sulfide.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Thermal polymerization of diaryl disulfides to yield poly(arylene sulfides)

The reaction of aromatic compounds and sulfur monochloride is investigated as a convenient route to prepare disulfides. Bis[4-[(4-bromophenyl)oxy]phenyl] disulfide (1), bis[4-[(4-bromophenyl)thio]-phenyl] disulfide (II), and bis-[[[(4-bromophenyl)sulfonyl]phenyl]oxy]phenyl] disulfide (III) were prepared through the electrophilic reaction of sulfur monochloride with aromatic compound catalyzed by SiO 2 . The thermal polymerization of the disulfide I results in the formation of high molecular weight poly(thio-1,4-phenyleneoxy-1,4-phenylene) (PPOS; M w =141 000) which is a high crystalline polymer with high stability after melting. The crystallographic data reveal that the resulting PPOS and poly(phenylene sulfide) both possess an orthorhombic unit cell

Thioalkylation of Reactive Aromatic Compounds with α-(Benzotriazol-1-yl)benzyl Phenyl Sulfide

1-[α-(Phenylthio)benzyl]- and 1-[(4-methylphenyl)(phenylthio)methyl]benzotriazole, readily available from benzotriazole, an aldehyde and thiophenol, react with a variety of active aromatic compounds under mild conditions to give the thioalkylation products in moderate to good yields

Radicals in flames: Analysis via scavenging reaction

Radicals in flames can be quantitatively analyzed by condensing flame gases along with a radical scavenger. Gas phase samples were taken from fuel-rich and sooting premixed low-pressure flames (27 mbar) by a nozzle beam. They were frozen simultaneously with an excess of dimethyl disulfide (DMDS) at liquid nitrogen temperature. High condensing efficiencies were achieved when both sample and scavenger alike had condensed on the inner surface of a hollow sphere. The scavenging reaction between a radical and the DMDS had taken place in the condensed phase and yielded a stable methylthio compound. The products were separated and identified by using the GC/MS-technique. This novel method was applied to ethyne/oxygen (=2.50) and benzene/oxygen (=1.80_ flames. Aside from the stable condensable flame products, such as polyynes and aromatic hydrocarbons, mono- and poly-methylthio compounds could be analyzed depending on the number of radical sites per molecule. Among the scavenged radicals aromatic radicals like phenyl, benzyl, indenyl, naphthyl, and the phenoxy radical, as well as a number of aliphatic radicals, including ethynyl, C 2 , C 3 H, and the carbenes CH 2 , C 3 H 2 , and C 5 H 2 , could be detected. Concentration profiles of radicals in both flames are reported and subsequently discussed. Conclusions are drawn concerning the polyynes, the formation of aromatic structures by the combustion of aliphatic fuels, and the reactions of aromatic compounds in sooting flames.

ChemInform Abstract: Convenient Synthesis of Primary Amides (III) by Friedel‐Crafts Reaction of Aromatic Compounds (I) with Trimethylsilyl Isocyanate (II).

ChemInformVolume 20, Issue 50 Isocyclic Compounds ChemInform Abstract: Convenient Synthesis of Primary Amides (III) by Friedel-Crafts Reaction of Aromatic Compounds (I) with Trimethylsilyl Isocyanate (II). V. P. KOZYUKOV, V. P. KOZYUKOV Gos. NII khim. i tekhnol. elementoorg. soed., MoskvaSearch for more papers by this authorVIK. P. KOZYUKOV, VIK. P. KOZYUKOV Gos. NII khim. i tekhnol. elementoorg. soed., MoskvaSearch for more papers by this authorE. V. MUZOVSKAYA, E. V. MUZOVSKAYA Gos. NII khim. i tekhnol. elementoorg. soed., MoskvaSearch for more papers by this authorV. F. MIRONOV, V. F. MIRONOV Gos. NII khim. i tekhnol. elementoorg. soed., MoskvaSearch for more papers by this author V. P. KOZYUKOV, V. P. KOZYUKOV Gos. NII khim. i tekhnol. elementoorg. soed., MoskvaSearch for more papers by this authorVIK. P. KOZYUKOV, VIK. P. KOZYUKOV Gos. NII khim. i tekhnol. elementoorg. soed., MoskvaSearch for more papers by this authorE. V. MUZOVSKAYA, E. V. MUZOVSKAYA Gos. NII khim. i tekhnol. elementoorg. soed., MoskvaSearch for more papers by this authorV. F. MIRONOV, V. F. MIRONOV Gos. NII khim. i tekhnol. elementoorg. soed., MoskvaSearch for more papers by this author First published: December 12, 1989 https://doi.org/10.1002/chin.198950144AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume20, Issue50December 12, 1989 RelatedInformation

ChemInform Abstract: Manganese(III)‐Mediated Formylation of Aromatic Compounds in the Presence of Malonic Acid.

AbstractWhile the known reaction of aromatic compounds with Mn(III) acetate (V) gives mainly acetoxymethylated products (by attack of carboxymethyl radicals), aldehydes such as (II)/(VII) and/or acids such as (III)/(VIII) are obtained in the presence of malonic acid (IV).

Anodic reactions of aromatic compounds

Anodic reactions of aromatic compounds

ChemInform Abstract: Acid‐Catalyzed Reactions of Aromatic Compounds with Alkanes and Cycloalkanes.

AbstractFriedel‐Crafts alkylations are accelerated by ultrasound ifthe initial reaction temp. are sufficient to start an ionic fragmentation chain.

ChemInform Abstract: Synthesis of 1‐(Substituted‐Aryl)methylthiomethanephosphonates by Friedel‐Crafts Reaction of Aromatic Compounds with Chloro(methylthio)methanephosphonate.

AbstractDie im Titel genannten Verbindungen (IV) werden in hohen Ausbeuten durch Friedel‐Crafts‐Alkylierung der Aromaten (III) mit dem Chlormethylphosphonat (II) erhalten.

Electrochemical reactivity of aromatic compounds for use in Li cells

The electrochemical reactivity of aromatic compounds coupled with Li in LiClO4-propylene carbonate was studied. Simple aromatic compounds, triphenylmethane compounds and quinone imine dyes were used. Discharge results for aromatic cathode-Li cells indicated that the relation between discharge voltage measured and reduction potential reported was approximately linear, which suggested that the discharge products were ion complexes. Also, the discharge voltage increased with an increase of their electron accepting groups and with a decrease of the electron donating strength of alkyl groups in their amino end groups. Among these compounds, rosaniline derivatives, bromo-substituted phenol red and thiazine dyes showed higher discharge voltages than 2.5 V. Methylene blue (MB) showed the largest energy density of 363 Wh kg−1. Details of MB charge-discharge behavior were examined. The dynamic charge-discharge tests and cyclic voltammetry results suggested that the MB-Li cell could be cycled up to 2e per mol of MB depth. Direct reaction between the Li anode and dissolved MB seemed to be small as indicated by the Li+ ion conductive film formation on the Li anode.

ChemInform Abstract: AROMATIC IODINATION WITH ALUMINUM AND COPPER(II) CHLORIDES AND IODINE

Aryl iodides have been synthesized by a simple reaction of aromatic compounds with iodine and an equimolecular mixture of aluminum and copper(II) chlorides. The reaction is widely capable of application, especially to liquid aromatic substrates, with fair to excellent yields.

Nitration in aqueous nitric acid: the rate profile and the limiting reaction rates

Rate coefficients for the nitration of a series of quaternary ammonium ions have been used to establish a rate profile for reaction in 63.7–100% nitric acid at 25 °C and to estimate the concentration of nitronium ions in the aqueous media. The kinetics of nitration of a series of reactive aromatic compounds (mainly phenolic ethers) in aqueous nitric acid have been analysed in terms of a first-order rate coefficient and the zeroth-order rate of formation of the nitronium ion. The first-order rate coefficients approach a limiting value as the reactivity of the aromatic substrate is increased and this value is as expected for the rate-limiting formation of an encounter pair (ArH·NO2+). The lifetime of nitronium ions in 60.4% nitric acid (t½ca. 5 × 10–8 s) has been calculated from the zeroth-order rate at 25 °C and used to show that the formation of the encounter pair (ArH·NO2+) occurs by the diffusion together of the components, not by pre-association. The studies on the more reactive aromatic compounds were carried out in the presence of hydrazine since this was shown to prevent the nitrous-acid catalysed reactions previously observed.