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Topic: Electrophilic substitution reaction

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Nucleophilic substitution reaction

Aromatic hydrocarbon

Organic chemistry

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	JEE Syllabus : IIT JEE Syllabus
		Preparation, properties and reactions of alkanes: Homologous series, physical properties of alkanes (melting points, boiling points and density); Combustion and halogenation of alkanes; Preparation of alkanes by Wurtz reaction and decarboxylation reactions.
		Reactions of benzene: Structure and aromaticity; Electrophilic substitution reactions: halogenation, nitration, sulphonation, Friedel-Crafts alkylation and acylation; Effect of o-, m- and p-directing groups in monosubstituted benzenes.
		Phenols: Acidity, electrophilic substitution reactions (halogenation, nitration and sulphonation); Reimer-Tieman reaction, Kolbe reaction.
	www.iitjee.org /iit-jee-syllabus.html (1806 words)

	Aromatic Reactivity
		A demonstration of bromine substitution and addition reactions is helpful at this point, and a virtual demonstration may be initiated by clicking here.
		This activation or deactivation of the benzene ring toward electrophilic substitution may be correlated with the electron donating or electron withdrawing influence of the substituents, as measured by molecular dipole moments.
		A practical concern in the use of electrophilic aromatic substitution reactions in synthesis is the separation of isomer mixtures.
	www.cem.msu.edu /~reusch/VirtualText/benzrx1.htm (2788 words)

	NationMaster - Encyclopedia: Electrophilic substitution reaction
		In the multistep Lehmstedt-Tanasescu reaction, one of the electrophiles is a N-nitroso intermediate.
		Organic substitution reactions are classified in several main organic reaction types depending on whether the reagent that brings about the substitution is considered an electrophile or a nucleophile, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical or whether the substrate is aliphatic or aromatic.
		Electrophiles are involved in electrophilic substitution reactions and particularly in electrophilic aromatic substitutions.
	www.nationmaster.com /encyclopedia/Electrophilic-substitution-reaction (285 words)

	Electrophilic aromatic substitution - Wikipedia, the free encyclopedia
		Electrophilic aromatic substitution or EAS is an organic reaction in which an atom, usually Hydrogen, in an aromatic system is replaced by an electrophile.
		In the multistep Lehmstedt-Tanasescu reaction, one of the electrophiles is a N-nitroso intermediate.
		Examples of electrophilic substitutions to pyrrole are the Pictet-Spengler reaction and the Bischler-Napieralski reaction.
	en.wikipedia.org /wiki/Electrophilic_substitution_reaction (1184 words)

	Substitution reaction - Wikipedia, the free encyclopedia
		In organic chemistry, the electrophilic and nucleophilic substitution reactions are of prime importance.
		Organic substitution reactions are classified in several main organic reaction types depending on whether the reagent that brings about the substitution is considered an electrophile or a nucleophile, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical or whether the substrate is aliphatic or aromatic.
		Electrophiles are involved in electrophilic substitution reactions and particularly in electrophilic aromatic substitutions.
	en.wikipedia.org /wiki/Substitution_reaction (215 words)

	Substitution reaction - Biocrawler (Site not responding. Last check: )
		In a substitution reaction, a group of a particular compound is replaced by another group.
		In organic chemistry, the electrophilic and nucleophilic substitution reactions are of prime importance.
		Organic substitution reactions are classified in several main organic reaction types depending on whether the reagent that brings about the substitution is considered a electrophile or a nucleophile, whether a reactive intermediate involved in the reaction is a carbocation, a carbanion or a free radical or whether the substrate is aliphatic or aromatic.
	www.biocrawler.com /encyclopedia/Substitution_reaction (172 words)

	Contents : (Site not responding. Last check: )
		Reactions of alkynes : hydrogenation - hydration - halogenation - hydrohalogenation - oxidation - ozonolysis - acidity of acetylenic protons.
		Reactions of benzene : the structure of benzene - aromaticity and Huckel rule - mechanism of electrophilic substitution - nitration - sulphonation - halogenation - Friedel-Craft’s alkylation and acylation.
		Electrophilic substitution of benzene derivatives : effect of different groups on the reactivity of the ring towards electrophilic substitution and orientation of the electrophile to the different positions - classification of the groups according to activation and orientation - oxidation and halogenation of alkylbenzenes.
	www.kaau.edu.sa /mmohamed/Contents.htm (511 words)

	Heteroaromatic Reaction Mechanisms
		Electrophiles react preferentially with the lone pair of the nitrogen to generate the pyridinium ion which, being positively charged, is unreactive towards electrophilic substitution.
		Substitution is preferred at C–5 and C–8 as the intermediates can profit from resonance stabilization without disrupting the aromaticity of the heteroaromatic ring.
		Electrophilic Aromatic Substitution of Indole Indole shows reactivity comparable with that of pyrrole with the exception that electrophilic substitution occurs at C–3 as this can involve stabilization of the intermediate carbocation by mesomeric donation from the nitrogen without destruction of the homoaromatic ring.
	users.ox.ac.uk /~mwalter/web_05/year2/arom2/hetarom_rxn_mech.shtml (586 words)

	Reference.com/Encyclopedia/Electrophilic aromatic substitution
		Electrophilic aromatic substitution or EAS is an organic reaction in which an atom, usually hydrogen, appended to an aromatic system is replaced by an electrophile.
		Other reactions that follow an electrophilic aromatic substitution pattern are a group of aromatic formylation reactions including the Vilsmeier-Haack reaction, the Gattermann Koch reaction and the Reimer-Tiemann reaction.
		In the first step of the reaction mechanism for this reaction, the electrophile A is attacked by the electron-rich aromatic ring which in the simplest case is benzene.
	www.reference.com /browse/wiki/Electrophilic_aromatic_substitution (1195 words)

	Encyclopedia :: encyclopedia : Organic chemistry (Site not responding. Last check: )
		Organic chemistry is the scientific study of the structure, properties, composition, reactions, and synthesis of organic compounds that by definition contain carbon.
		It is presumed that functional group F is bonded to one of the carbon atoms in R. R is often one of the hydrocarbon categories mentioned previously.
		The example above is a substitution reaction, since Y is substituted for F. Important concerns of a reaction include whether it will occur spontaneously determined by the Gibb's free energy, what heat is produced or needed in terms of Enthalpy and what unintended products are formed as well.
	www.hallencyclopedia.com /Organic_chemistry (1034 words)

	INTRODUCTION (Site not responding. Last check: )
		the intermediate of an electrophilic substitution reaction is a resonance stabilized carbocation.
		Friedel-Crafts reactions are electrophilic substitution reactions in which the attacking electrophile is a carbocation.
		Acylation reactions, where acyl groups sre attached to organic reagents is an easy method for the synthesis of aryl ketones.
	www.neiu.edu /~jhramire/Friedel-crafts/introduction.htm (217 words)

	OCHem
		This reaction is typical of the aromatic ring, and derivatives of benzene, C
		During this reaction a cyclohexadienyl cation intermediate is formed in which the positive charge is initially localized on the carbon atom to which the amino group is attached (This is called the ipso carbon.).
		The difference in the levels of the lower dashed blue line and the lower dashed red line is a measure of the resonance stabilization that the amino group affords the pi system of the aromatic ring relative to a hydrogen atom.
	www.usm.maine.edu /~newton/Chy251_253/Lectures/EASReactions/EASReactionsII.html (2688 words)

	Electrophilic substitution - Definition, explanation
		Electrophilic substitution reactions are chemical reactions in which an electrophile displaces another group, typically but not always hydrogen.
		The ΔG° is close to zero for an electrophilic substitution reaction with benzene.
		Electrophilic substitution on benzene results in a predictable outcome in the case of monosubstitution.
	www.calsky.com /lexikon/en/txt/e/el/electrophilic_substitution.php (693 words)

	Defintion of electrophile_electrophilic - Chemistry Dictionary
		An electrophile (or electrophilic reagent) is a reagent that forms a bond to its reaction partner (the nucleophile) by accepting both bonding electrons from that reaction partner.
		An "electrophilic substitution reaction" is a heterolytic reaction in which the reagent supplying the entering group acts as an electrophile.
		The term "electrophilic" is also used to designate the apparent polar character of certain radicals, as inferred from their higher relative reactivities with reaction sites of higher electron density.
	www.chemicool.com /definition/electrophile_electrophilic.html (92 words)

	Electrophilic Aromatic Discount
		Electrophilic aromatic substition reactions are among the most common and most important in organic synthesis.
		Slide of Since the reagents and conditions employed in these reactions are electrophilic these discount reactions are commonly referred to as Electrophilic Aromatic Substitution.
		This is in contrast to electrophilic addition reactions Since the reagents and conditions employed in these jar reactions are electrophilic these reactions are commonly referred to as.
	www.youseek.org /electrophilic-aromatic-substitution.htm (0 words)

	Benzene ring - Benzenering
		The aromatic products of the reaction are then separated from the reaction mixture by extraction with any one of a number of solvents, including diethylene glycol or sulfolane, and benzene is then separated from the other aromatics by distillation.
		Electrophilic aromatic substitution is a general method of substituting aromatic rings such as benzene.
		The reaction is the acylation of an aromatic ring (such as benzene) with an acyl chloride using a strong Lewis acid catalyst.
	www.kopete.org /Benzene-ring.html (1932 words)

	Emphasis Topics for the Third Exam
		You should be able to derive a TS model for the rds of a general electrophilic substitution reaction.
		You should be able to explain the deactivation effect by applying the Method of Competing TS's to the TS's for substitution of an electrophile (E+)meta to an EWG such as nitro with that for the substitution of the same electrophile upon benzene, itself, where there is no substituent present to destabilize the positive charge.
		This works, in contrast to the reaction of the previous part(involving ammonia), because the alkyl azide is not a good enough nucleophile to react with an alkyl halide.
	research.cm.utexas.edu /nbauld/teach/emphtopB3.html (2995 words)

	The MACiE Dictionary
		An electrophile is a chemical species that forms a bond to its reaction partner (the nucleophile) by accepting both bonding electrons.
		A nucleophilic substitution reaction is a heterolytic reaction in which the reagent supplying the entering group acts as a nucleophile.
		A reaction, either elementary or stepwise, in which one atom or group in a molecular entity is replaced by another atom or group.
	www-mitchell.ch.cam.ac.uk /macie/glossary.html (3307 words)

	Lab Reports - Chemistry 110 and Chemistry 210 & 211
		The reaction of the aromatic ring and the electrophile is characterized as an electrophilic substitution reaction.
		The first is the attack on the ring by an electrophilic reagent to form a carbocation (this is characterized as the rate deteriming or the slow step).
		However the text revealed that since this electrophilic aromatic substitution reaction occurs in acidic media, the basic amino group is converted into the cationic ammonium group (-NH) which is electron withdrawing and would be meta not para directing.
	www.miracosta.cc.ca.us /home/dlr/report03.htm (1480 words)

	BENZENE
		The characteristic reactions of saturated hydrocarbon are substitution reaction.
		Therefore when any electrophillic reagent reacts with benzene then the hydrogen atom is replaced by attacking molecule to form substituted benzene.
		As a result of these reactions, the aeromatic character of ring is lost and benzene is reduced to saturated cyclic compound.
	www.awamimarkaz.com /education/members/NOTES/CHEMXII/Benzene.asp (2111 words)

	[No title]
		Aromatic substitution reactions are important synthetic reactions that are used to make a variety of products including high-performance plastics and acetylsalicylic acid (more commonly known as aspirin).
		Another example of electrophilic aromatic substitution is the Kolbe reaction, where carbon dioxide is used as the electrophile (instead of the nitro group, which would be nitration).2 This reaction is used in the synthesis of aspirin.
		Nitric acid isn’t a strong enough electrophile to react with the aromatic benzene ring, but the nitronium ion with the positive charge on the nitrogen is a strong electrophile and can react with the double bond of the methyl benzoate.
	www.plu.edu /~iversoai/doc/ochem-ii.doc (1260 words)

	Azo Dye Formation (Site not responding. Last check: )
		Coupling reaction: The diazotized sulfanilic acid reacts with 2-naphthol and 1-naphthylamine to produce an acidic and basic azo dye alternatively (2).
		The diazonium kation is a relatively weak electrophile.
		Electrophilic substitution of 2-naphthol occurs preferentially at the 1-position.
	www.uni-regensburg.de /Fakultaeten/nat_Fak_IV/Organische_Chemie/Didaktik/Keusch/D-Azo-Dyes-e.htm (304 words)

	Organic Chemistry at Penn State: Reactions (Site not responding. Last check: )
		Electrophilic addition of halogens to alkenes in the presence of water.
		equivalent to ozonolysis of the corresponding olefins (reaction 10)
		E1 mechanism for tertiary or secondary allylic or benzylic substrates: the leaving group departs in a unimolecular rate-limiting step, generating the carbocation, which in the second step is deprotonated (with base) on the carbon adjacent to the cationc center, yielding the olefin; carbocation rearrangements may compete
	courses.chem.psu.edu /chem38/reactions/reactions.html (993 words)

	Untitled Document (Site not responding. Last check: )
		Other proposed reaction mechanisms for electrophilic substitution reactions in ferrocene involve a pi-complex between the Cp ring and the electrophile or a radical intermediate (2).
		Nucleophilic substitution is useful on ferrocene derivatives such as bromoferrocene in making derivatives that cannot be made using electrophilic substitution such as hydroxy- and aminoferrocene (8).
		An electrophilic substitution reaction is then used to replace the lithium, resulting in a disubstituted ring.
	www.nd.edu /~bbodnar/ferrocene.htm (7461 words)

	Ch328_Lec_16
		Electrophilic attack on the ring is the most important type of aromatic reaction, as we might expect.
		A reaction coordinate diagram for this reaction is shown below (note that it has the same shape and general characteristics as the halogenation of ethylene we saw earlier).
		However, in these reactions there is such a difference in the transition state energies that we just don't see equilibrium being achieved, so from a practical point of view it is the transition state energy which determines final product.
	www.humboldt.edu /~rap1/C328.Su04/C328Notes/C328nLec16.htm (1125 words)

	PSIgate - Physical Sciences Information Gateway: Search/Browse Results (Site not responding. Last check: )
		In it, the mechanism for the formation of nitrobenzene from benzene by an electrophilic substitution reaction between benzene and a mixture of concentrated nitric acid and concentrated sulphuric acid is explained.
		An illustrated outline is provided of the electrophilic substitution reaction between benzene and alkenes in the presence of a mixture of aluminium chloride and hydrogen chloride as catalysts.
		An illustrated outline is provided of the electrophilic substitution reaction between benzene and chlorine or bromine in the presence of a catalyst such as aluminium chloride or iron.
	www.psigate.ac.uk /roads/cgi-bin/psisearch.pl?term1=benzene&subject=All&limit=0 (1328 words)

	[No title] (Site not responding. Last check: )
		An important electrophilic aromatic substitution reaction is the Friedel-Crafts alkylation which forms alkyl benzenes.
		In this reaction an alkyl halide reacts with an aromatic compound in the presence of a Lewis Acid catalyst, often AlCl
		Rearrangement of intermediate electrophile occurs by a shift of a hydrogen atom.
	people.uis.edu /gtram1/organic/aromatics/friedel-crafts.htm (165 words)

	E
		An electrophile (or electrophilic reagent) is a reagent that forms a bond to its reaction partner (the nucleophile) by accepting both bonding electrons from that reaction partner.
		An "electrophilic substitution reaction" is a heterolytic reaction in which the reagent supplying the entering group acts as an electrophile.
		The term "electrophilic" is also used to designate the apparent polar character of certain radicals, as inferred from their higher relative reactivities with reaction sites of higher electron density.
	www.chem.qmul.ac.uk /iupac/gtpoc/E.html (2409 words)

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