4.1 IUPAC Nomenclature of Alkyl Halides tinue to develop concepts of structure and bonding, and see how structure affects prop- erties. A review of acids and bases constitutes an important part of this chapter in which a qualitative approach to proton-transfer equilibria will be developed that will be used throughout the remainder of the text 4. 1 IUPAC NOMENCLATURE OF ALKYL HALIDES The IUPAC rules permit alkyl halides to be named in two different ways, called func- The IUPAC rules permit cer. tional class nomenclature and substitutive nomenclature. In functional class nomencla. ain common alkyl grou ture the alkyl group and the halide (fluoride, chloride, bromide, or iodide)are desig- clude n-propyl, isopropyl nated as separate words. The alkyl group is named on the basis of its longest continuous n-butyl, sec-butyl, isobutyl chain be ng at the carbon to which the halogen is attached CH3F CH3CH, CH, CHCH,CI CH3CH, CHCH, CH, CH Methyl fluoride Pentyl chloride 1-Ethylbutyl bromide Cyclohexyl iodide Substitutive nomenclature of alkyl halides treats the halogen as a halo-(fluoro- chloro bromo, or iodo-)substituent on an alkane chain. The carbon chain is numbered in the direction that gives the substituted carbon the lower locant. CH3CH, CH, CH2 CH,F CH3 CHCH,CH2 CH3 CH3CH,CHCH,CH3 1-Fluoropentane 3-lodopentane When the carbon chain bears both a halogen and an alkyl substituent, the two substituents are considered of equal rank, and the chain is numbered so as to give the lower number to the substituent nearer the end of the chain CH3 CHCH,CH, CHCH,CH3 CH3 CHCH, CH, CHCH-CH3 CH3 5-Chloro-2-methy heptane 2-Chloro-5-methy heptane PROBLEM 4.1 Write structural formulas, and give the functional class and sub stitutive names of all the isomeric alkyl chlorides that have the molecular formula CaHgCI Substitutive names are preferred, but functional class names are sometimes more convenient or more familiar and are frequently encountered in organic chemistry the IUPAC rules. the term 4.2 IUPAC NOMENCLATURE OF ALCOHOLS instead of "functional class Functional class names of alcohols are derived by naming the alkyl group that bears the hydroxyl substituent(OH) and then adding alcohol as a separate word. The chain is always numbered beginning at the carbon to which the hydroxyl group is attached Substitutive names of alcohols are developed by identifying the longest continu- Back Forward Main Menu Study Guide ToC Student OLC MHHE Websitetinue to develop concepts of structure and bonding, and see how structure affects prop￾erties. A review of acids and bases constitutes an important part of this chapter in which a qualitative approach to proton-transfer equilibria will be developed that will be used throughout the remainder of the text. 4.1 IUPAC NOMENCLATURE OF ALKYL HALIDES The IUPAC rules permit alkyl halides to be named in two different ways, called func￾tional class nomenclature and substitutive nomenclature. In functional class nomencla￾ture the alkyl group and the halide ( fluoride, chloride, bromide, or iodide) are desig￾nated as separate words. The alkyl group is named on the basis of its longest continuous chain beginning at the carbon to which the halogen is attached. Substitutive nomenclature of alkyl halides treats the halogen as a halo- ( fluoro-, chloro-, bromo-, or iodo-) substituent on an alkane chain. The carbon chain is numbered in the direction that gives the substituted carbon the lower locant. When the carbon chain bears both a halogen and an alkyl substituent, the two substituents are considered of equal rank, and the chain is numbered so as to give the lower number to the substituent nearer the end of the chain. PROBLEM 4.1 Write structural formulas, and give the functional class and sub￾stitutive names of all the isomeric alkyl chlorides that have the molecular formula C4H9Cl. Substitutive names are preferred, but functional class names are sometimes more convenient or more familiar and are frequently encountered in organic chemistry. 4.2 IUPAC NOMENCLATURE OF ALCOHOLS Functional class names of alcohols are derived by naming the alkyl group that bears the hydroxyl substituent (±OH) and then adding alcohol as a separate word. The chain is always numbered beginning at the carbon to which the hydroxyl group is attached. Substitutive names of alcohols are developed by identifying the longest continu￾ous chain that bears the hydroxyl group and replacing the -e ending of the 5-Chloro-2-methylheptane CH3CHCH2CH2CHCH2CH3 CH3 W Cl W 1 23 4 56 7 2-Chloro-5-methylheptane CH3CHCH2CH2CHCH2CH3 Cl W CH3 W 1 23 4 56 7 CH3CH2CH2CH2CH2F 1-Fluoropentane 2-Bromopentane CH3CHCH2CH2CH3 Br W 5 4 3 2 1 1 23 4 5 3-Iodopentane CH3CH2CHCH2CH3 I W 1 2 34 5 CH3CH2CH2CH2CH2Cl Pentyl chloride CH3F Methyl fluoride CH3CH2CHCH2CH2CH3 Br W 1-Ethylbutyl bromide H I Cyclohexyl iodide 12 3 4 4.1 IUPAC Nomenclature of Alkyl Halides 127 The IUPAC rules permit cer￾tain common alkyl group names to be used. These in￾clude n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl, tert-butyl, and neopentyl (Section 2.10). Prior to the 1993 version of the IUPAC rules, the term “radicofunctional” was used instead of “functional class.” Back Forward Main Menu TOC Study Guide TOC Student OLC MHHE Website