AROMATIC COMPOUNDS

REFERS TO COMPOUNDS THAT CONTAIN A BENZENE RING OR RINGS DEFINITION REFERS TO COMPOUNDS THAT CONTAIN A BENZENE RING OR RINGS

RULE: Name the substituent and add the word benzene. NOMENCLATURE MONOSUBSTITUTED RULE: Name the substituent and add the word benzene.

Name: butylbenzene ethylbenzene chlorobenzene

Monosubstituted (common name) TOLUENE PHENOL ANILINE

disubstituted There are three different ways that two groups can be attached to a benzene ring. PREFIX POSITION Ortho (o) 1,2 Meta (m) 1,3 Para (p) 1,4

1,2-dichlorobenzene or o-dichlorobenzene 1-chloro-3-ethylbenzene or m-chloroethylbenzene 1-fluoro-4-isopropylbenzene or p-fluoroisopropylbenzene

disubstituted IF one of the substituents is part of a common root, name the molecule as a derivative of the monosubstituted benzene one with the higher priority is used as the root name for the compound and the other substituent is named as a prefix

disubstituted If two groups on the benzene ring are different, alphabetize the name of the substituents preceding the word BENZENE.

polysubstituted NUMBER TO GIVE THE LOWEST POSSIBLE NUMBERS TO THE SUBSTITUENTS. ALPHABETIZE THE SUBSTITUENTS. WHEN SUBSTITUENTS ARE PART OF COMMON ROOTS, NAME THE MOLECULE AS A DERIVATIVE OF THAT MONOSUBSTITUTED BENZENE. THE SUBSTITUENT THAT COMPRISES THE COMMON ROOT IS LOCATED AT C1, BUT “1” IS OMITTED FROM THE NAME.

AROMATIC COMPOUNDS WITH MORE THAN 1 RING

SAMPLE PROBLEM

EXERCISES

AROMATIC DRUGS, SUNSCREEN & CARCINOGENS

Sun Protection Factor SPF is a measure of how much solar energy (UV radiation) is required to produce sunburn on protected skin (i.e., in the presence of sunscreen) relative to the amount of solar energy required to produce sunburn on unprotected skin. As the SPF value increases, sunburn protection increases. http://www.fda.gov/AboutFDA/CentersOffices/CDER/ucm106351.htm In general, a sunscreen with: SPF 2 blocks 50 percent of UVB rays SPF 4 blocks 75 percent of UVB rays SPF 8 blocks 87 percent of UVB rays SPF 15 blocks 93 percent of UVB rays SPF 30 blocks 97 percent of UVB rays SPF 50 blocks 98 percent of UVB rays SPF 100 blocks 99 percent of UVB rays UVA Protection Ratings There is currently no easy way to know how effective a sunscreen is against UVA rays. New FDA sunscreen labeling, in addition to possibly placing a cap of SPF 50+, would introduce a new UVA four-star system so that parents could easily figure out if a sunscreen offered low UVA protection (one star) or the highest UVA protection (four stars). The new labels would also clearly state if a sunscreen offered 'no UVA protection.'

REACTIONS OF AROMATIC COMPOUNDS Like the alkenes, aromatic compounds undergo a characteristics type of reaction. Aromatic compounds undergo substitution reaction NOT addition reaction.

p Why? Substitution of H by X keeps the stable aromatic ring intact. Benzene does not undergo addition reaction like other unsaturated hydrocarbons because the product would not contain a benzene ring

Three specific reactions of benzene are considered: CHLORINATION (- Cl )  

NITRATION (- NO2)

SULFONATION (- SO3H)

SEATWORK