应用化学专业英语 教学课件 ppt 作者 黄忠 谢普会 付颖 主编lesson 7 Nomenclature of organic compounds 2课件.ppt

Lesson 7 Organic Nomenclature Compounds in which carbon is the principal element. Writing formulas. . . Condensed: CH3CH(CH3)CH = CHCH(CH3)CH3 Kekule’ Skeletal Hydrocarbons. . . Contain only hydrogen and carbon. Types: Alkane: single bonds; saturated (largest possible number of hydrogens/carbon atom. [CnH2n+2] Alkene: one or more carbon-carbon double bond. Unsaturated hydrocarbon. Alkyne: one carbon-carbon triple bond. Unsaturated hydrocarbon. Aromatic: carbon atoms connected in a planar ring. Unsaturated hydrocarbon. Hydrocarbons. . . Relatively nonpolar. (covalent bonds) Insoluble in water. (like dissolves like) Less volatile with increasing molar mass. (because of London dispersion forces) Alkanes. . . [CnH2n+2] Methane: CH4 major component of natural gas; home heating; gas stoves; hot water heaters Ethane: C2H6 Propane: C3H8 used for home cooking and heating; gas grills Butane: C4H10 disposable lighters and fuel canisters for gas camping stoves. Name consists of. . . 1. Prefix Where are the substituents? 2.Parent How many carbons in the longest chain? 3. Suffix Which family? If two different chains of equal length are present: choose the one with the larger number of branch points as the parent. Rules for naming alkanes. . . Longest continuous chain of carbon atoms gives the root name 1. For alkanes, add –ane to the root: Meth: C Eth: C2 Prop: C3 But: C4 2. For alkanes beyond butane, use the Greek root for the number of carbons then add -ane to the end. C-C-C-C-C-C = hexane pent=5; hex=6; hept=7; oct=8; non=9; dec= 10 Substituent Group(s) added in place of a removed hydrogen. Alkanes as a substituent group. . . Alkyl substituents: 1. Remove a hydrogen from the alkane. C2H6 is ethane 2. Drop the -ane and add -yl. -C2H5 is ethyl Positions of substituent groups are specified by numbering the longest chain sequentially. (Use the lowest number for the position of the substituent group) The l