Slide Number 1Slide Number 2Slide Number 3Hydrocarbons:Petroleum Industry Alkanes and GasolineAlkanes and GasolineSlide Number 8Slide Number 9Alkanes AlkanesSlide Number 12Slide Number 13Slide Number 14Slide Number 15Slide Number 16Slide Number 17Slide Number 18Common Branched Alkyl GroupsSlide Number 20Slide Number 21Slide Number 22Slide Number 23Slide Number 24Slide Number 25Slide Number 26Slide Number 27Slide Number 28Slide Number 29Slide Number 30Slide Number 31Slide Number 32Slide Number 33Slide Number 34Slide Number 35Nomenclature of AlkynesAlkenolsVinyl and Allyl GroupsAlkenes: Cis & TransSlide Number 40Slide Number 41Slide Number 42Slide Number 43Slide Number 44Slide Number 45Slide Number 46Slide Number 47Slide Number 48Slide Number 49Slide Number 50Conformations of Cyclohexane: Chair & Boat Slide Number 52Cyclohexane : Boat Conformation Slide Number 54A Conformational Analysis of MethylcyclohexaneSlide Number 56Slide Number 57Slide Number 58Slide Number 59Slide Number 60Slide Number 61Slide Number 62Reactivity of Alkanes: OverviewSlide Number 64Slide Number 65Slide Number 66Structural Information: Index of Hydrogen DeficiencySlide Number 68AnnouncementsReviewSlide Number 71Slide Number 72Slide Number 73Slide Number 74Slide Number 75Slide Number 76Slide Number 77Slide Number 78Slide Number 79Slide Number 80Slide Number 81Extra slidesSlide Number 83Slide Number 84Slide Number 85Slide Number 86Slide Number 87Slide Number 88Slide Number 89Slide Number 90Slide Number 91Slide Number 92Slide Number 93Slide Number 94Slide Number 95Slide Number 96Slide Number 97Slide Number 98Chapter 4 Alkanes: Nomenclature, Conformational Analysis, and an Introduction to Synthesis 1In this chapter : 1. How to name many simple organic molecules 2. The flexible, three-dimensional nature of organic molecules 3. An organic reaction that can convert alkenes and alkynes to alkanes 2Reminder: • Alkanes and cycloalkanes are hydrocarbons in which all the carbon-carbon (C–C) bonds are single bonds • Hydrocarbons that contain C═C: Alkenes • Hydrocarbons that contain C≡C: Alkynes 3Hydrocarbons: Max length hydrocarbon chain 4 ~390oC Crude Oil 44 60-80 12-16 36 6-8 4Petroleum Industry • Distillation is the first step in refining petroleum. Its components are separated based on different volatility • More than 500 different hydrocarbons compounds are contained in petroleum distillates boiling below 200oC • The fractions taken contain mixture of alkanes of similar boiling points • Mixtures of alkanes can be used as fuels, solvents and lubricants 5catalysts~ 500oCmixture of alkanes(C12 and higher)highly branchedhydrocarbons(C5 - C10)Alkanes and Gasoline • Converting hydrocarbons from other fractions of petroleum into gasoline by “catalytic cracking” • Isooctane burns smoothly in combustion engines 2,2,4-Trimethylpentane (isooctane)(C12H18)CH3CCH3CH3CH2C CH3CH3H6Alkanes and Gasoline • Octane rating describe the ratio of isooctane to heptane • 87% isooctane and 13% heptane • Rated as 87-octane gasoline isooctaneheptane"octanerating"100 07Shapes of Alkanes All carbon atoms in alkanes and cycloalkanes are sp3 hybridized, and they all have a tetrahedral geometry “Straight-chain” alkanes have a zig-zag orientation when they are in their most straight orientation. Straight chain alkanes are also called unbranched alkanes. 8Branched alkanes have at least one carbon which is attached to more than two other carbons. 9Alkanes • Distillation is used to separate components based on different volatility in refineries. The fractions taken contain mixture of alkanes of similar boiling points • Constitutional Isomers have different physical properties (melting point, boiling point, densities etc.). 10The number of constitutional isomers possible for a given molecular formula increases rapidly with the number of carbons. Alkanes 11IUPAC Nomenclature of Alkanes, Alkyl Halides and Alcohols Before the end of the 19th century compounds were named using nonsystematic nomenclature. These “common” or “trivial” names were often based on the source of the compound or a physical property. The International Union of Pure and Applied Chemistry (IUPAC) started devising a systematic approach to nomenclature in 1892. The fundamental principle in devising the system was that each different compound should have a unique unambiguous name. The basis for all IUPAC nomenclature is the set of rules used for naming alkanes. Each different compound shall have a unique name 12Nomenclature of Unbranched Alkanes • The ending for all the names of alkanes is –ane • The names of most alkanes stem from Greek and Latin one meth- two eth- three prop- four but- five pent- 13Nomenclature of Unbranched Alkyl groups The unbranched alkyl groups are obtained by removing one hydrogen from the alkane and named by replacing the -ane of the corresponding alkane with –yl. 14Nomenclature of Branched-Chain Alkanes (IUPAC) 1. Locate the longest continuous chain of carbons; this is the parent chain and determines the parent name. 2. Number the longest chain beginning with the end of the chain nearer the substituent. Designate the location of the substituent. 3. When two or more substituents are present, give each substituent a number corresponding to its location on the longest chain. Substituents are listed alphabetically. CH3CH2CH2CH2CHCH37654321(3-Methylheptane)CH2CH3CH3CH2CH2CH2CHCH3654321(2-Ethylhexane)CH2CH3CH3CH2CH2CH2CHCH37654321(3-Methylheptane)CH2CH3CH3CH2CH2CH2CHCH31 23456(5-Methylheptane)CH2CH37154. When two or more substituents are identical, use the prefixes di-, tri-, tetra- etc. Commas are used to separate numbers from each other. The prefixes are used in alphabetical prioritization. When two chains of equal length compete to be parent, choose the chain with the greatest number of substituents . 5. When branching first occurs at an equal distance from either end of the parent chain, choose the name that gives the lower number at the first point of difference 161 35 72(6-Ethyl-2-methyloctane)4 6 886 4 27(3-Ethyl-7-methyloctane)5 3 11 3 5 72(2-Methyl-6-ethyloctane)4 6 8In Class Practice: Which one is the correct name? 1) 2) 3) 176. When two chains of equal length compete for selection as parent chain, choose the chain with the greater number of substituents 6425(2,3,5-Trimethyl-4-propylheptane)31764