Baixe IUPAC Nomenclatura de Quim. Orgânica (1979) e outras Notas de estudo em PDF para Engenharia Química, somente na Docsity! IUPAC Nomenclature of Organic Chemistry Recommendations 1979 Acyclic Hydrocarbons Rule A-1. Saturated Unbranched-chain Compounds and Univalent Radicals 1.1 - The first four saturated unbranched acyclic hydrocarbons are called methane, ethane, propane and butane. Names of the higher members of this series consist of a numerical term, followed by "-ane" with elision of terminal "a" from the numerical term. Examples of these names are shown in the table below. The generic name of saturated acyclic hydrocarbons (branched or unbranched) is "alkane". Examples of names: (n = total number of carbon atoms) n n n n 1 Methane 11 Undecane 21 Henicosane 31 Hentriacontane 2 Ethane 12 Dodecane 22 Docosane 32 Dotriacontane 3 Propane 13 Tridecane 23 Tricosane 33 Tritriacontane 4 Butane 14 Tetradecane 24 Tetracosane 40 Tetracontane 5 Pentane 15 Pentadecane 25 Pentacosane 50 Pentacontane 6 Hexane 16 Hexadecane 26 Hexacosane 60 Hexacontane 7 Heptane 17 Heptadecane 27 Heptacosane 70 Heptacontane 8 Octane 18 Octadecane 28 Octacosane 80 Octacontane 9 Nonane 19 Nonadecane 29 Nonacosane 90 Nonacontane 10 Decane 20 Icosane 30 Triacontane 100 Hectane 1.2 - Univalent radicals derived from saturated unbranched acyclic hydrocarbons by removal of hydrogen from a terminal carbon atom are named by replacing the ending "-ane" of the name of the hydrocarbon by "- yl". The carbon atom with the free valence is numbered as 1. As a class, these radicals are called normal, or unbranched chain, alkyls. Examples to Rule A-1.2 Acyclic Hydrocarbons Rule A-2. Saturated Branched-chain Compounds and Univalent Radicals 2.1 - A saturated branched acyclic hydrocarbon is named by prefixing the designations of the side chains to the name of the longest chain present in the formula. Example to Rule A-2.1 The following names are retained for unsubstituted hydrocarbons only: Isobutane Neopentan e Isopentane Isohexane 2.2 - The longest chain is numbered from one end to the other by Arabic numerals, the direction being so chosen as to give the lowest numbers possible to the side chains. When series of locants containing the same number of terms are compared term by term, that series is "lowest" which contains the lowest number on the occasion of the first difference. This principle is applied irrespective of the nature of the substituents. Examples to Rule A-2.2 2.25 - Univalent branched radicals derived from alkanes are named by prefixing the designation of the side chains to the name of the unbranched alkyl radical possessing the longest possible chain starting from the carbon atom with the free valence, the said atom being numbered as 1. Examples to Rule A-2.25 1-Methylpentyl 2-Methylpentyl 5-Methylhexyl The following names may be used for the unsubstituted radicals only: Isopropyl Isobutyl sec-Butyl tert-Butyl Isopentyl Neopentyl tert- Pentyl 2.3 - If two or more side chains of different nature are present, they are cited in alphabetical order. The alphabetical order is decided as follows: (i) The names of simple radicals are first alphabetized and the multiplying prefixes are then inserted. Examples to Rule A-2.3(i) ethyl is cited before methyl, thus 4-Ethyl-3,3-dimethylheptane (ii) The name of a complex radical is considered to begin with the first letter of its complete name. Examples to Rule A-2.3(ii) dimethylpentyl (as complete single substituent) is alphabetized under "d", thus 7-(1,2-Dimethylpentyl)-5-ethyltridecane (iii) In cases where names of complex radicals are composed of identical words, priority for citation is given to that radical which contains the lowest locant at the first cited point of difference in the radical. Examples to Rule A-2.3(iii) 2.4 - If two or more side chains are in equivalent positions, the one to be assigned the lower number is that cited first in the name. Examples: to Rule A-2.4 2.5 - The presence of identical unsubstituted radicals is indicated by the appropriate multiplying prefix di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, deca-, undeca, etc. 3.6 - When there is a choice for the fundamental chain of a radical, that chain is selected which contains (1) the maximum number of double and triple bonds; (2) the largest number of carbon atoms; and (3) the largest number of double bonds. Examples to Rule A-3.6 Acyclic Hydrocarbons Rule A-4. Bivalent and Multivalent Radicals 4.1 - Bivalent and trivalent radicals derived from univalent acyclic hydrocarbon radicals whose authorized names end in "-yl" by removal of one or two hydrogen atoms from the carbon atom with the free valences are named by adding "-idene" or "-idyne", respectively, to the name of the corresponding univalent radical. The carbon atom with the free valence is numbered as 1. The name "methylene" is retained for the radical Examples to Rule A-4.1 Methylidyne Ethylidene Ethylidyne Vinylidene Isopropylidene 4.2 - The names of bivalent radicals derived from normal alkanes by removal of a hydrogen atom from each of the two terminal carbon atoms of the chain are ethylene, trimethylene, tetramethylene, etc. Examples to Rule A-4.2 Pentamethylene Hexamethylene Names of the substituted bivalent radicals are derived in accordance with Rules A-2.2 and A-2.25. Example to Rule A-4.2a The following name is retained: 4.3 - Bivalent radicals similarly derived from unbranched alkenes, alkadienes, alkynes, etc., by removing a hydrogen atom from each of the terminal carbon atoms are named by replacing the endings "-ene", "-diene", "-yne", etc., of the hydrocarbon name by "-enylene", "-dienylene", "-ynylene", etc., the positions of the double and triple bonds being indicated where necessary. Example to Rule A-4.3 The following name is retained: Names of the substituted bivalent radicals are derived in accordance with Rule A-3.4. Example to Rule A-4.3 4.4 - Trivalent, quadrivalent and higher-valent acyclic hydrocarbon radicals of two or more carbon atoms with the free valences at each end of a chain are named by adding to the hydrocarbon name the terminations "-yl" for a single free valence, "-ylidene" for a double, and "-ylidyne" for a triple free valence on the same atom (the final "e" in the name of the hydrocarbon is elided when followed by a suffix beginning with "- yl"). If different types are present in the same radical, they are cited and numbered in the order "-yl", "- ylidene", "-ylidyne". Examples to Rule A-4.4 Butanediylidene Butanediylidyne 1-Propanyl-3-ylidene Propadienediylidene 2-Pentenediylidyne 1-Butanyliden-4-ylidyne 4.5 - Multivalent radicals containing three or more carbon atoms with free valences at each end of a chain and additional free valences at intermediate carbon atoms are named by adding the endings "-triyl", "- tetrayl", "-diylidene", "diyl-ylidene", etc., to the hydrocarbon name. Examples to Rule A-4.5 Monocyclic Hydrocarbons Rule A-11. Unsubstituted Compounds and Radicals 11.1 - The names of saturated monocyclic hydrocarbons (with no side chains) are formed by attaching the prefix "cyclo" to the name of the acyclic saturated unbranched hydrocarbon with the same number of carbon atoms. The generic name of saturated monocyclic hydrocarbons (with or without side chains) is "cycloalkane". Examples to Rule A-11.1 11.2 - Univalent radicals derived from cycloalkanes (with no side chains) are named by replacing the ending "-ane" of the hydrocarbon name by "-yl", the carbon atom with the free valence being numbered as 1. The generic name of these radicals is "cycloalkyl". Examples to Rule A-11.2 11.3 - The names of unsaturated monocyclic hydrocarbons (with no side chains) are formed by substituting "-ene", "-adiene", "-atriene", "-yne", "-adiyne", etc., for "-ane" in the name of the corresponding cycloalkane. The double and triple bonds are given numbers as low as possible as in Rule A-3.3. Examples to Rule A-11.3 The name "benzene" is retained. 11.4 - The names of univalent radicals derived from unsaturated monocyclic hydrocarbons have the endings "-enyl", "-ynyl", "-dienyl", etc., the positions of the double and triple bonds being indicated according to the principles of Rule A-3.3. The carbon atom with the free valence is numbered as 1, except as stated in the rules for terpenes (see Rules A-72 to A-75). Examples to Rule A-11.4 The radical name "phenyl" is retained. 11.5 - Names of bivalent radicals derived from saturated or unsaturated monocyclic hydrocarbons by removal of two atoms of hydrogen from the same carbon atom of the ring are obtained by replacing the endings "- ane", "-ene", "-yne", by "-ylidene", "-enylidene" and "-ynylidene", respectively. The carbon atom with the free valences is numbered as 1 except as stated in the rules for terpenes. Examples to Rule A-11.5 11.6 - Bivalent radicals derived from saturated or unsaturated monocyclic hydrocarbons by removing a hydrogen atom from each of two different :carbon atoms of the ring are named by replacing the endings "- ane", "-ene", "-diene", "-yne", etc., of the hydrocarbon name by "-ylene", "-enylene", "-dienylene", "- ynylene", etc., the positions of the double and triple bonds and of the points of attachment being indicated. Preference n lowest numbers is given to the carbon atoms having the free valences. Examples to Rule A-11.6 The following name is retained: Monocyclic Hydrocarbons Rule A-12. Substituted Aromatic Compounds 12.1 - The following names for monocyclic substituted aromatic hydro carbons are retained: Examples to Rule A-12.1 12.2 - Other monocyclic substituted aromatic hydrocarbons are named as derivatives of benzene or of one of the compounds listed in Part .1 of this rule. However, if the substituent introduced into such a compound is identical with one already present in that compound, then the substituted compound is named as a derivative of benzene (see Rule 61.4). 12.3 - The position of substituents is indicated by numbers except that o- (ortho), m- (meta) and p- (para) may be used in place of 1,2-, 1,3-, and 1,4-, respectively, when only two substituents are present. The lowest numbers possible are given to substituents, choice between alternatives being governed by Rule A-2 so far as applicable except that when names are based on those of compounds listed in Part .1 of this rule the first priority for lowest numbers is given to the substituent(s) already present in those compounds. Examples to Rule A-12.3 12.4 - The generic name of monocyclic and polycyclic aromatic hydrocarbons is "arene".