Starting with benzene as the only aromatic organic starting material, outline a plausible synthesis route for each of the listed compounds showing all reagents, conditions and intermediate substitution products clearly. Aromatic compounds with only one group attached to the benzene ring. There are therefore 6 electrons in the circle of p orbitals. Huckels rule states that an aromatic compound must have pi electrons in the overlapping p orbitals in order to be aromatic n in this formula represents any integer. Aromatics are hydrocarbons, organic compounds that consist exclusively of the elements carbon and hydrogen without which life would not be possible on earth. Naming aromatic compounds isnt quite so straightforward as naming chain compounds. For each of the following structural diagrams, write the iupac name. Naming aromatic compounds aromatic compounds are cyclic hydrocarbons containing a benzene structure. Recognize the methods for naming aromatic compounds, including iupac nomenclature and historical names.
For substituted benzene rings where the substituent contains more than six carbons, the benzene ring is noted by using a phenyl prefix on the alkane name. But any planar cyclic hydrocarbon that contains 2, 6, 10, 14. We will be covering the naming of benzene derivatives, stability of aromatic compounds, electrophilic aromatic substitution, and nucleophilic aromatic substitution. Aromatic hydrocarbons are compounds that contain a benzene ring. Benzene derivatives were originally isolated from fragrant oils. The simplest example of this class of compounds, benzene, was isolated from illuminating gas by michael faraday in 1825. The goal of the system is to give each structure a unique and unambiguous name, and to correlate each name with a unique and unambiguous. The stability that results from a ring being aromatic. Aromatic compounds or arenes include benzene and benzene derivatives. Aromatic compounds early in the history of organic chemistry late.
The simplest organic compounds are composed of carbon and hydrogen and are known as hydrocarbons. Polycyclic aromatic hydrocarbons aromatic compounds can have rings that share a set of carbon atoms fused rings compounds from fused benzene or aromatic heterocyclic rings are themselves aromatic naphthalene. Aromatic compounds definition, example, properties. Nomenclature of organic compounds mainly three systems are adopted for naming an organic compound. Though trivial names are not recommended, iupac rules allow their use with common aromatic compounds, such as methylbenzene toluene, hydroxybenzene phenol, and aminobenzene. Nomenclature of aromatic compounds trivial names are more commonly used for aromatic compounds than is the case with other compound families in organic chemistry. Naming aromatic compounds introduction to chemistry. Naming aromatic compounds benzene and phenyl in organic. Aromatic compounds organic compounds containing one or more benzene rings and their functionalized derivatives are called aromatic compounds. Short summary of iupac nomenclature of organic compounds introduction the purpose of the iupac system of nomenclature is to establish an international standard of naming compounds to facilitate communication. Aromatic compounds are chemical compounds which consist of conjugated planar ring systems accompanied by delocalized pi electron clouds in place of individual alternating double and single bonds. For anti aromatic compounds, such as cyclobutadiene and cyclooctatetraene, there will be unpaired electrons in bonding, nonbonding or antibonding mos. Short summary of iupac nomenclature of organic compounds. I mentioned in the last video that 99% of the aromatic compounds that youll see in a chemistry or organic chemistry class is either going to be benzene or a molecule derived from benzene.
These compounds comprise a distinct class, called aromatic hydrocarbons. Aromatic compounds and aromaticity solomons 6 edition. Each corner of the hexagon has a carbon atom with a hydrogen attached. If the compound is branched, the name is determined similar to that used for the alkanes. Antiaromaticity is a characteristic of a cyclic molecule with a. The group of atoms remaining when a hydrogen atom is removed from an aromatic compound is called an aryl group. The main aromatics are benzene, toluene and the xylenes.
Aromatic compounds are also interesting because of their presumed role in the origin of life as precursors to nucleotides and amino acids. The structure of benzene in the resonance hybrid, the six electrons from the three. The cyclic oligoenes 1,3,5cycloheptatriene and 1,3,5,7cyclooctatetraene, for example, are nonaromatic compounds whose reactions, such as additions and hydrogenations, are typical for. The alkanes and cycloalkanes are also members of a larger class of compounds referred to as. Aromatic hydrocarbons are compounds that contain a benzene ring structure. The dashed lines inside the hexagon in the resonance hybrid of benzene. Test your knowledge of aromatic compounds in this interactive quiz and printable. Aromatic compounds are a class of hydrocarbons that possess much greater stability than their conjugated unsaturated system suggests. This longest chain may not be written in a straight line.
All the carboncarbon bonds are of equal length, and all the bond angles are 120. It was also quickly discovered that these aromatic compounds. In the years to follow, this compound and homologues. For substituted benzene rings where the substituent contains less than six carbons, the. Most, but not all, aromatic compounds are based on benzene, c 6 h 6, which has a ring of six carbon atoms and has the symbol.
Aromatic compounds must have a p orbital on every atom. What is the difference between antiaromatic and non. This is a very good class starter, and also an assessment to check and challenge students understanding of the topic. Aromatic compounds are a large class of molecules that include a planar ring of atoms attached with alternating single and double bonds. Predict whether compounds and ions are aromatic, nonaromatic, or antiaromatic. Huckels rule is strictly for monocyclic aromatic compound, its application to polycyclic aromatic compounds is tenuous. A resonance picture of bonding in benzene resonance hybrid 6. Nonbenzenoid aromatic compounds do not contain benzene rings examples are cyclopentadienyl anion and the aromatic annulenes except 6 annulene azulene has substantial resonance energy and also substantial separation of charge, as shown in the electrostatic potential map. Molecular orbitals of benzene the aromatic system of benzene. There have been many conventions for naming organic compounds some have. We start to see that aromatic compounds are cyclic compounds, containing a certain number of. The odors we smell everyday are made up of aromatic compounds. Aromatic compounds ppt and worksheet with answers teaching. Document in microsoft internet explorer people ubcs.
Organic compounds containing one or more benzene rings and their functionalized derivatives are called aromatic compounds. First check to see if the compound has a planar, cyclic pi. Simply put, aliphatic compounds are compounds that do not incorporate any. Heterocyclic compounds alkaloids medical chemistry lecture 8 200 7 j. Ch 3chchchch3 ch3 this compound is named 4methyl2pentene. Poly aromatic hydrocarbons are components of atmospheric pollution and are known carcinogens. Next we consider a class of hydrocarbons with molecular formulas like those of unsaturated hydrocarbons, but which, unlike the alkenes, do not readily undergo addition reactions. Feb 11, 2017 this aromatic hydrocarbons benzene type compounds naming ppt and worksheet with answers provided will help students in the nomenclature of aromatic compounds. Apr 02, 2015 common aromatic compounds study guide cheat sheet includes the names and structures of various substituted benzene compounds that you are required to know throughout your organic chemistry course. Some representative aromatic compounds and their uses are listed in table. Aromatic compounds are produced from a variety of sources, including petroleum and coal tar. Start by checking that you can do all those which involve groups that you know about, and. The alkanes are classified as continuous chain that is, unbranched if all the carbon atoms in the chain are linked to no more than two other car.
What is the difference between antiaromatic and nonaromatic. At least the first row since they are more common, and you will encounter them all them when dealing with aromatic compounds. Some disubstituted benzene rings also have common names. For a compound to be considered aromatic, it must be flat, cyclic, and conjugated and it must obey huckels rule. Nomenclature of aromatic compounds nh2 ch3 1 6 2 cl 5 1 6 a b c 3 4. Our mission is to provide a free, worldclass education to anyone, anywhere. All of the organic substances we have looked at so far have been aliphatic benzene belongs to the aromatic class. Naming benzene derivatives introduction video khan academy.
Often, more than one name is acceptable and its not uncommon to find the old names still in use as well. Aromatic compounds organic chemistry science khan academy. Unfortunately, there are no other options and you need to memorize these names. Elucidation of the structure posed a problem the molecular formula c6h6 indicated a highly unsaturated compound double andor triple bonds but benzene. Polyaromatic hydrocarbons are components of atmospheric pollution and are known carcinogens. So what i want to do in this video is just familiarize you with some of these molecules and how to name them. This is a simple example of a halogen attached to the benzene ring. Heterocyclic compounds are organic compounds that contain rings composed of carbon and other atoms heteroatoms in natural heterocycles mostly nitrogen, sulfur, and oxygen. Introduction it is important that organic compounds are corrrectly and unambiguously named so that there can be absolutely no confusion about what compounds are actually being reported or described. Naming rules for organic compounds the names of organic molecules are divided into three parts.
Nomenclature of organic compounds th t t f ithere are two systems of naming 1. However, cyclic oligoenes do not universally have benzenelike chemical and physical properties. Consult your textbook for more details and examples. Sometimes an aromatic group is found as a substituent bonded to a nonaromatic entity or to another aromatic ring. You can recognize the aromatic compounds in this text by the presence of one or more benzene rings in their structure. Hydrocarbons are further identified as being aliphatic or aromatic nothing to do with smell. The distinctive electronic structure of aromatic leads to some distinctive reactivity. Name each compound using both the common name and the iupac name. All aromatic compounds are based on benzene, c 6 h 6, which has a ring of six carbon atoms and has the symbol. In this type of reaction, the electrophile must be especially reactive electron deficient. There are,however, examples of aromatic compounds which do not contain a benzene ring but instead contain other highly unsaturated ring. Common aromatic compounds study guide cheat sheet includes the names and structures of various substituted benzene compounds that you are required to know throughout your organic chemistry course.
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