13. Arkham Legacy The Next Batman Video Game Is this a Rumor? The aryl halides are less reactive than benzene towards electrohilic substitution reactions because the ring it some what deactivated due to -I effect of halogens that shows tendency to withdraw electrons from benzene ring. The resonance energy of anthracene is less than that of naphthalene. Is gasoline a mixture of volatile alkanes and aromatic hydrocarbons? There is good evidence that the synthesis of phenol from chlorobenzene does not proceed by the addition-elimination mechanism (SNAr) described above. For example, treatment of para-chlorotoluene with sodium hydroxide solution at temperatures above 350 C gave an equimolar mixture of meta- and para-cresols (hydroxytoluenes). and other reactive functional groups are included in this volume. Yet gradually, as experimentally found, in this group of three, benzene is the most, anthracene the least aromatic compound. I guess it has to do with reactant based arguments that the atomic coefficients for the two center carbon atoms (C-9 and C-10) are higher than from the outer cycle (C-1 and C-4). In anthracene the rings are con- To see examples of this reaction, which is called the Birch Reduction, Click Here. It is worth noting that these same conditions effect radical substitution of cyclohexane, the key factors in this change of behavior are the pi-bonds array in benzene, which permit addition, and the weaker C-H bonds in cyclohexane. The products from substitution reactions of compounds having a reinforcing orientation of substituents are easier to predict than those having antagonistic substituents. Note: As the energy increases the stability of the system decreases and as a result of this that system becomes more reactive. The explanation for this curious repositioning of the substituent group lies in a different two-step mechanism we can refer to as an elimination-addition process. Chemical oxidation occurs readily, giving anthraquinone, C14H8O2 (below), for example using hydrogen peroxide and vanadyl acetylacetonate. Examples of these reductions are shown here, equation 6 demonstrating the simultaneous reduction of both functions. Benzene is 150 kJ mol-1 more stable than expected. Why anthracene is more reactive than benzene and naphthalene? Naphthalene has two aromatic rings, but only 10 pi electrons (rather than the twelve electrons that it would prefer). Can you lateral to an ineligible receiver? . The major product obtained for DHA was anthracene (80% yield) as analyzed by gas chromatography (GC, Figure S22). When applied to aromatic halides, as in the present discussion, this mechanism is called SNAr. In the bromination of benzene using Br_2 and FeBr_3, is the intermediate carbocation aromatic? For example, acetylation of aniline gives acetanilide (first step in the following equation), which undergoes nitration at low temperature, yielding the para-nitro product in high yield. The presence of electron-withdrawing groups (such as nitro) ortho and para to the chlorine substantially enhance the rate of substitution, as shown in the set of equations presented on the left below. Generally, central ring of anthracene is considered more reactive than the other two rings and -complex at the C9-position of anthracene could be stabilized by two benzene rings which might prevent rearomatization [28] . For example, with adding #"Br"_2#. By acetylating the heteroatom substituent on phenol and aniline, its activating influence can be substantially attenuated. How to tell which packages are held back due to phased updates. If you continue to use this site we will assume that you are happy with it. When a benzene ring has two substituent groups, each exerts an influence on subsequent substitution reactions. Legal. How many of the following compounds are more reactive than benzene towards electrophilic substitution. Due to this , the reactivity of anthracene is more than naphthalene. Electrophilic substitution occurs at the "9" and "10" positions of the center ring, and oxidation of anthracene occurs readily, giving anthraquinone . Phenanthrene has 17 kcal/mol less resonance energy than 3benzene rings . Similar exquisite degree of control at the individual polymeric chain level for producing functional soft nanoentities is expected to become a reality in the next few years through the full development of so-called &amp;amp;quot;single chain technology&amp;amp . Phenanthrene is more stable than anthracene due to the larger stability of the -system of the former, which is more aromatic. Aromatic hydrocarbons are cyclic, planar compounds that resemble benzene in electronic configuration and chemical behavior. c) It has a shorter duration of action than adrenaline. Molecular orbital . In previous studies, the origin of the higher stability of kinked polycyclic aromatic hydrocarbons (PAHs) was found to be better -bonding interactions, i.e., larger aromaticity, in kinked as compared . The resonance energy of anthracene is less than that of naphthalene. An early method of preparing phenol (the Dow process) involved the reaction of chlorobenzene with a concentrated sodium hydroxide solution at temperatures above 350 C. D = Electron Donating Group (ortho/para-directing)W = Electron Withdrawing Group (meta-directing). Phenanthrene has bb"17 kcal/mol" less resonance energy than 3xx"benzene rings". Why are azulenes much more reactive than benzene? Haworth synthesis is a multistep preparation of phenanthrenes from naphthalenes by means of the FriedelCrafts acylation with succinic anhydride, followed by a Clemmensen reduction or WolffKishner reduction, cyclization, reduction, and dehydrogenation. Sign Upexpand_more. A smaller HOMO-LUMO gap means a more reactive system, despite it having resonance throughout. { Characteristics_of_Specific_Substitution_Reactions_of_Benzenes : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Electrophilic_Aromatic_Substitution : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Electrophilic_Substitution_of_Disubstituted_Benzene_Rings : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Nucleophilic_Reactions_of_Benzene_Derivatives : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Reactions_of_Fused_Benzene_Rings : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Reactions_of_Substituent_Groups : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Substitution_Reactions_of_Benzene_Derivatives : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, { Benzene : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Electrophilic_Substitution_of_Disubstituted_Benzene_Rings : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Friedel-Crafts_Acylation" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "Halogenation_of_Benzene-The_Need_for_a_Catalyst" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Halogenation_of_Benzene_and_Methylbenzene : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Modifying_the_Influence_of_Strong_Activating_Groups : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Nitration_and_Sulfonation_of_Benzene : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Nitration_of_Benzene_and_Methylbenzene : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Other_Reactions_of_Benzene_and_Methylbenzene : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Reactions_of_Fused_Benzene_Rings : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Reactions_of_Substituent_Groups : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Substitution_Reactions_of_Benzene_and_Other_Aromatic_Compounds : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", Substitution_Reactions_of_Benzene_Derivatives : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, [ "article:topic-category", "authorname:wreusch", "showtoc:no", "license:ccbyncsa", "licenseversion:40" ], https://chem.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fchem.libretexts.org%2FBookshelves%2FOrganic_Chemistry%2FSupplemental_Modules_(Organic_Chemistry)%2FArenes%2FReactivity_of_Arenes%2FBenzene%2FReactions_of_Fused_Benzene_Rings, \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}}}\) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\), Nucleophilic Reactions of Benzene Derivatives, status page at https://status.libretexts.org. Direct bromination would give the 4-bromo derivative. The possibility that these observations reflect a general benzylic activation is supported by the susceptibility of alkyl side-chains to oxidative degradation, as shown in the following examples (the oxidized side chain is colored). . ASK. In most other reactions of anthracene, the central ring is also targeted, as it is the most highly reactive. The group which increase the electron density on the ring also increase the . ISBN 0-8053-8329-8. Anhydrides are highly reactive to nucleophilic attack and undergo many of the same reactions as . Naphthalene is more reactive than benzene, both in substitution and addition reactions, and these reactions tend to proceed in a manner that maintains one intact benzene ring. Benzene has the molecular formula C 6 H 6 and is the simplest aromatic hydrocarbon. Anthracene is a highly conjugated molecule and exhibits mesomerism. You can do the same analysis for anthracene, and you will probably find that nitration at position 9 (on the middle ring) is favored. menu. However, the addition products of nitration and halogenation readily undergo elimination to form the 9-substitution products: John D. Robert and Marjorie C. Caserio (1977) Basic Principles of Organic Chemistry, second edition. The sixth question takes you through a multistep synthesis. Homework help starts here! The strongly activating hydroxyl (OH) and amino (NH2) substituents favor dihalogenation in examples 5 and six. Phenols are highly prone to electrophilic substitution reactions due to rich electron density. This stabilization in the reactant reduces the reactivity (stability/reactivity principle). Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. However, ortho-chloroanisole gave exclusively meta-methoxyaniline under the same conditions. In this instance, it is more beneficial than "the ring" symbolizing the delocalised electron system, as this helps you to account for the precise number of -electrons before the reaction (starting materials), during the reaction (the mechanism), and after the reaction (the product). The C1C2 bond is 1.36 long, whereas the C2C3 bond length is 1.42 . Any of the alkenes will be readily converted to alcohols in the presence of a dilute aqueous solution of H 2 SO 4 , but benzene is inert. One can see that in both cases the marginal rings are ricer in -electrons than the middle ring, but for phenanthrene this unequal distribution is more pronounced than in anthracene. One example is sulfonation, in which the orientation changes with reaction temperature. Question 6. Which is more reactive naphthalene or anthracene? Because of their high nucleophilic reactivity, aniline and phenol undergo substitution reactions with iodine, a halogen that is normally unreactive with benzene derivatives. study resourcesexpand_more. In the absence of steric hindrance (top example) equal amounts of meta- and para-cresols are obtained. The C1C2 bond is 1.36 long, whereas the C2C3 bond length is 1.42 . What is the structure of the molecule named phenylacetylene? The reactions of the higher hydrocarbons with electrophilic reagents are more complex than of naphthalene. Their resonance form is represented as follows: Therefore, fluorobenzene is more reactive than chlorobenzene. An electrophile is a positively charged species or we can say electron deficient species. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Three canonical resonance contributors may be drawn, and are displayed in the following diagram. This means that naphthalene has less aromatic stability than two isolated benzene rings would have. By definition, alkenes are hydrocarbons with one or more carbon-carbon double bonds (R2C=CR2), while alkynes are hydrocarbons with one or more carbon-carbon triple bonds (R-CC-R). Anthracene is fused linearly, whereas phenanthrene is fused at an angle. Is it suspicious or odd to stand by the gate of a GA airport watching the planes? Just as an expert carpenter must understand the characteristics and limitations of his/her tools, chemists must appreciate the nature of their "tools" when applying them to a specific synthesis. The smallest such hydrocarbon is naphthalene. Benzene is less reactive as it is more stable due to the delocalised pi system where the six p electrons of the carbon atoms are delocalised above and below the ring, forming a continuous pi bond and giving the molecule greater stability compared to alkenes where the electrons are localised between certain atoms. Despite keen interest in the development of efficient materials for the removal of polycyclic aromatic hydrocarbons (PAHs) in wastewater, the application of advanced composite materials is still unexplored and needs attention. Since the HOMO-LUMO gap gets smaller when the system gets larger, it's very likely that the gap is so small for pyrene that the resonance stabilization (which increases this gap) isn't enough to make it unreactive towards electrophilic addition. Answer (1 of 4): benzene more stable than naphthalene So naphthalene is more reactive compared to single ringed benzene . Which position of phenanthrene is more reactive? The best answers are voted up and rise to the top, Not the answer you're looking for? I ran a calculation using http://www.chem.ucalgary.ca/SHMO and the coefficients on C-9 and C-10 were 0.44, whereas those on C-1 and C-4 were only 0.31. What are the steps to name aromatic hydrocarbons? Naphthalene is more reactive than benzene, both in substitution and addition reactions, and these reactions tend to proceed in a manner that maintains one intact benzene ring. The kinetically favored C1 orientation reflects a preference for generating a cationic intermediate that maintains one intact benzene ring. The permanganate oxidant is reduced, usually to Mn(IV) or Mn(II). As Anthracene is present naturally without any reaction with coal tar then it is neutral in nature. The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. Which results in a higher heat of hydrogenation (i.e. Compounds in which two or more benzene rings are fused together were described in an earlier section, and they present interesting insights into aromaticity and reactivity. PARTICIPATION OF HOMO & LUMO IN ELECTROPHILIC ADDITION. Why is maleic anhydride so reactive? Electrophilic substitution occurs at the "9" and "10" positions of the center ring, and oxidation of anthracene occurs readily, giving anthraquinone . Whereas chlorine atom involves 2p-3p overlap. Why is there a voltage on my HDMI and coaxial cables? When two electrons are removed, i.e., dicationic systems are analyzed, the reverse trend is obtained, so the linear isomer is more stable than the kinked one. Chemistry Stack Exchange is a question and answer site for scientists, academics, teachers, and students in the field of chemistry. In strong sunlight or with radical initiators benzene adds these halogens to give hexahalocyclohexanes. Electrophilic nitration and Friedel-Crafts acylation reactions introduce deactivating, meta-directing substituents on an aromatic ring. Bromination of both phenol and aniline is difficult to control, with di- and tri-bromo products forming readily. . 22.8: Substitution Reactions of Polynuclear Aromatic Hydrocarbons. order of stability (or RE): Benzene > Phenanthrene ~ Naphthalene > Anthracene. Metal halogen exchange reactions take place at low temperature, and may be used to introduce iodine at designated locations. Symmetry, as in the first two cases, makes it easy to predict the site at which substitution is likely to occur. WhichRead More Give reasons involved. I invite you to draw the mechanisms by yourself: It may be helpful to add that benzene, naphthalene and anthracene are of course Hckel-aromatic compounds; with 6, 10 or 14 -electrons they fit into the rule of $(4n + 2)$. Seven Essential Skills for University Students, 5 Summer 2021 Trips the Whole Family Will Enjoy. ; Naphthalene has two rings, but best 10 pi electrons as opposed to the twelve electrons that it might choose. A smaller HOMO-LUMO gap means a more reactive system, despite it having resonance throughout. The reactions of the higher hydrocarbons with electrophilic reagents are more complex than of naphthalene. CHAT. The following diagram shows three oxidation and reduction reactions that illustrate this feature. The resonance stabilization energy of benzene is greater than that of these heteroaromatic compounds. Why are azulenes much more reactive than benzene? Additionally, when you react these fused aromatic rings, they always react to generate the most benzene rings possible. The major product for CHD oxidation was benzene (82%) as analyzed by 1 H NMR spectroscopy (Figures S23-S25). The resonance stabilization power for each compound is again less than three times that of benzene, with that for anthracene being lower than . This apparent nucleophilic substitution reaction is surprising, since aryl halides are generally incapable of reacting by either an SN1 or SN2 pathway. TimesMojo is a social question-and-answer website where you can get all the answers to your questions. Why is stormwater management gaining ground in present times? Electrophilic substitution of anthracene occurs at the 9 position. The hydroxyl group also acts as ortho para directors. Note that if two different sites are favored, substitution will usually occur at the one that is least hindered by ortho groups. Why is anthracene a good diene? When one substituent has a pair of non-bonding electrons available for adjacent charge stabilization, it will normally exert the product determining influence, examples 2, 4 & 5, even though it may be overall deactivating (case 2). We use cookies to ensure that we give you the best experience on our website. The 1,2 bonds in both naphthalene and antracene are in fact shorter than the other ring bonds, However, the overall influence of the modified substituent is still activating and ortho/para-directing. is 84 Kcal/mol and for naphthalene and benzene rings are 61 and 36 Kcal/mol respectively. to 30.5 Kcal/mol for naphthalene, 30.3 Kcal/mol for phen. An example of this method will be displayed below by clicking on the diagram. Here resonance energy per benzene ring decreases from 36 Kcal/mol for benzene to 30.5 Kcal/mol for naphthalene, 30.3 Kcal/mol for phenanthene and 28 Kcal/mol for anthracene. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. MathJax reference. We have already noted that benzene does not react with chlorine or bromine in the absence of a catalyst and heat. The resonance energy for phenanthrene is 92 Kcal/mol, that for anthracene is 84 Kcal/mol and for naphthalene and benzene rings are 61 and 36 Kcal/mol respectively. The major product is 1-nitronaphthalene. Are there tables of wastage rates for different fruit and veg? This contrasts with the structure of benzene, in which all the CC bonds have a common length, 1.39 . Naphthalene is more reactive than benzene, both in substitution and addition reactions, and these reactions tend to proceed in a manner that maintains one intact benzene ring. Home | About | Contact | Copyright | Report Content | Privacy | Cookie Policy | Terms & Conditions | Sitemap. It is well-known that kinked phenacenes are more stable than their isomeric linear acenes, the archetypal example being phenanthrene that is more stable than anthracene by about 4-8 kcal/mol. How many pi electrons are present in phenanthrene? Naphthalene. ; This manner that naphthalene has less aromatic stability than isolated benzene ring would have. For additional information about benzyne and related species , Click Here. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Interestingly, if the benzylic position is completely substituted this oxidative degradation does not occur (second equation, the substituted benzylic carbon is colored blue). Some distinguishing features of the three common nucleophilic substitution mechanisms are summarized in the following table. Since N is less electronegative than O, it will be slightly more stable than O with that positive charge. The Birch Reduction Another way of adding hydrogen to the benzene ring is by treatment with the electron rich solution of alkali metals, usually lithium or sodium, in liquid ammonia. Is anthracene more reactive than benzene? Site design / logo 2023 Stack Exchange Inc; user contributions licensed under CC BY-SA. These pages are provided to the IOCD to assist in capacity building in chemical education. Asking for help, clarification, or responding to other answers. Which carbon of anthracene are more reactive towards addition reaction? . The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. In most other reactions of anthracene, the central ring is also targeted, as it is the most highly reactive. This content is copyrighted under the following conditions, "You are granted permission for individual, educational, research and non-commercial reproduction, distribution, display and performance of this work in any format.". Compared with anthracene, K region may be an important electronic structure of phenanthrene for activation of CAR. The following equation illustrates how this characteristic of the sulfonic acids may be used to prepare the 3-bromo derivative of ortho-xylene. This means that naphthalene hasless aromatic stability than two isolated benzene rings would have. These equations are not balanced. Electrophilic substitution reactions take place more rapidly at C1, although the C2 product is more stable and predominates at equilibrium. Why are aromatic compounds such as toluene and oxygenated hydrocarbons such as ethanol generally How are the aromatic rings represented? Phenanthrene is more stable than anthracene due to the larger stability of the -system of the former, which is more aromatic. Therefore, o-hydroxy toluene is most reactive towards electrophilic reagent. The fifth question asks you to draw the products of some aromatic substitution reactions. Among PAHs, phenanthrene and anthracene are isomers consisting of three benzene rings. This is more favourable then the former example, because. The two structures on the left have one discrete benzene ring each, but may also be viewed as 10-pi-electron annulenes having a bridging single bond. Therefore the polycyclic fused aromatic . when the central ring opened, two benzene ring had been formed, this action leads to increase the stability (as we know the benzene . The recent ability to manipulate and visualize single atoms at atomic level has given rise to modern bottom-up nanotechnology. Explanation: Methyl group has got electron repelling property due to its high. Nitrogen nucleophiles will also react, as evidenced by the use of Sanger's reagent for the derivatization of amino acids. This means that naphthalene has less aromatic stability than two isolated benzene rings would have. This difference in fusions causes the phenanthrene to have five resonance structures which is one more than anthracene. The two structures on the left have one discrete benzene ring each, but may also be viewed as 10-pi-electron annulenes having a bridging single bond. To provide a reason for the observed regioselectivity, it is helpful to draw anthracene's aromatic -electron system in alternance of single and double bonds.In this instance, it is more beneficial than "the ring" symbolizing the delocalised electron system, as this helps you to account for the precise number of -electrons before the reaction (starting materials), during the reaction (the . Why anthracene is more reactive than naphthalene? Why is anthracene a good diene? Fluorine donates its lone pair of electrons by resonance better than the chlorine atom because the fluorine atom involves 2p-2p overlap. Thus, the groups may be oriented in such a manner that their directing influences act in concert, reinforcing the outcome; or are opposed (antagonistic) to each other. . That is why it pushes electron towards benzene ring thus the benzene ring in toluene molecule becomes activated for having higher density of negative charge compared to simple benzene molecule. As the number of fused aromatic rings increases, the resonance energy per ring decreases and the compounds become more reactive. therefore electron moves freely fastly than benzene . As expected from an average of the three resonance contributors, the carbon-carbon bonds in naphthalene show variation in length, suggesting some localization of the double bonds. Comments, questions and errors should be sent to whreusch@msu.edu. The structure and chemistry of more highly fused benzene ring compounds, such as anthracene and phenanthrene show many of the same characteristics described above . Hence, order of stability (or RE): Benzene > Phenanthrene ~ Naphthalene > Anthracene.In fact other fused polycyclic aromatic hydrocarbons react faster than benzene. As both these energies are less than the resonance energy of benzene, benzene is more stable than anthracene and phenanthrene. The structure and chemistry of more highly fused benzene ring compounds, such as anthracene and phenanthrene show many of the same characteristics described above. The strongest activating and ortho/para-directing substituents are the amino (-NH2) and hydroxyl (-OH) groups. I and III O B. I and V NH Diels-Alder adduct II III NH IV V NH View all products of Market Price & Insight. Surly Straggler vs. other types of steel frames. Following. Which is more reactive naphthalene or benzene? . Answer (1 of 5): The resonance energy for phenanthrene is 92 Kcal/mol, that for anthracene is 84 Kcal/mol and for naphthalene and benzene rings are 61 and 36 Kcal/mol respectively. More stable means less reactive . The order of aromaticity is benzene > thiophene > pyrrole > furan.

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