2ORGANIC CHEMISTRY: The study of compounds containing CARBON There are more than a 10 million organic compounds!
3AllotropesLonsdaleiteOne of two or more different molecular forms of the same element in the same physical state
4HYDROCARBONSHYDROCARBON PREFIXESThe simplest organic compounds that contain only carbon and hydrogenCarbon has 4 valence electrons, and therefore always forms 4 covalent bonds!Prefix# of CarbonsMeth-1Eth-2Prop-3But-4Pent-5Hex-6Hept-7Oct-8Non-9Dec-10
6Alkanes A hydrocarbon in which there are only single bonds In an alkane all the carbon-carbon bonds are single covalent bondsAll other bonds are carbon-hydrogen bondsThe carbon atoms in an alkane can be arranged in a straight chain or in a chain that has branches.Alkanes are called saturated compounds because they contain only single covalent bonds
7Straight Chain Alkanes Contain any number of carbon atoms, one after the other, in a chainHomologous Series: A constant increment of change in molecular structure from one compound in the series to the nextIn an alkane a CH2 group is the increment of change
8Naming Straight-Chain Alkanes Naming AlkanesDrawing a Structural FormulaFor all alkanes the name ends in -aneWrite the symbol for carbon as many times as necessary to get the proper chain lengthCount the carbon atoms and add the appropriate prefixComplete each carbons bonds with hydrogenName: C6H14Draw the structural formula for octane.
9Branched Chain Alkanes An alkane with one or more alkyl groupsSubstituent: An atom or group of atoms that can take the place of a hydrogen atom on a parent hydrocarbon moleculeParent Alkane: The longest continuous carbon chain of a branched–chain hydrocarbonAlkyl Group: A hydrocarbon substituent
10NAMING BRANCHED ALKANES EXAMPLE:Find the largest chain of carbons in the molecule (the parent structure)# the carbons in the main chain in sequence, starting so that the substituents will be on the carbons of the lowest possible numbersAdd numbers to the name of the substituent groups to identify their positionsUse prefixes to indicate the appearance of the same group more than once in the structural formulaList the names of the alkyl substituents in alphabetical orderCommas are used to separate #s. Hyphens to separate numbers and words. Entire name without spaces.
11PROPERTIES OF ALKANES Molecules of hydrocarbons are nonpolar molecules Attraction between nonpolar molecules are weak van der Waals forcesAlkanes of lower molar mass tend to be gases or liquids that boil at low temperaturesWill form a solution with nonpolar compounds because “Like dissolves Like”Will not form solutions with polar compounds
12UNSATURATED COMPOUNDS: Compounds that contain double or triple carbon-carbon bonds AlkenesAlkynesHydrocarbons that contain one or more carbon-carbon double-covalent bondsHydrocarbons that contain one or more carbon-carbon triple covalent bondsExamples:
13To Name Alkenes/Alkynes ExampleFind the longest chain in the molecule that contains the double/triple bond (parent chain). Name with the appropriate prefix and the ending –ene (for alkenes) or –yne (for an alkyne)Number the chain so the carbon atoms with the double-triple bonds have the lowest numbers. Include the number in the name if there is more than one possible location for the double-triple bond.Substituents are numbered and named as they are with alkanes
14Draw the structural formulas for: Propyne Propane Propene
15ISOMERS Compounds that have the same molecular formula but different molecular structures
16Structural Isomers Compounds that have the same molecular formulas but the atoms are joined in a different wayStructural isomers differ in physical properties such as melting/boiling pointsHave different chemical reactivities
17PROPERTIES Butane Structure Melting Point (C) -60 -217 MethylpropaneButaneStructureMelting Point (C)-60-217Boiling Point (C)3031StabilityReactively stable. Extremely flammableHighly flammableThe more highly branched the hydrocarbon, the lower the boiling point hydrocarbon
18STEREOISOMERS Molecules in which the atoms are joined in the same order, but the positions of the atoms inspace are different.1) Geometric Isomers: Atoms are joined in the same order but differ in orientation around a double bond.trans: Similar groups are on opposite sides of the double bondcis: Similar groups are on the same side of the double bond
20STEREOISOMERSOptical Isomers: Differ in the way that four different groups are arranged around a central carbon atom.Asymmetric Carbon: A carbon with 4 different atoms or groups attached
21FUNCTIONAL GROUPSOrganic compounds can be classified according to their functional group.Functional Group: A specific arrangment of atoms in an organic compound that is capable of characteristic chemical reactionsOrganic compounds can be classified by their functional groups!
23Halocarbons A class of organic compounds containing covalently bonded fluorine, chlorine, bromine oriodine.Naming: The halogen groups are named as substituents
24Halocarbons Properties: Weak van der Waals interactions called dispersion forcesForces increase with halogen substitutionMore highly halogenated organic compounds have higher boiling pointsVery few are found in nature
25Halocarbons1987 Montreal Protocol on Substances that Deplete the Ozone Layer and its Amendments, which have both high ozone depleting potentials (ODPs)
26Alcohols An organic compound with an –OH group Hydroxyl Group: The –OH functional group“In many ways, prohibition was the catalyst for the first (and arguably biggest) large-scale Do-It-Yourself science movement in the nation's history”. Robert T. Gonzalez, BBC
27Naming Alcohols1) Drop the –e ending of the parent alkane name and add the ending –ol2) Parent alkane is the longest continuous chain that includes the carbon attached to the hydroxyl group3) If the hydroxyl group can occur at more than one position, its position is designated with the lowest possible number.4) Alcohols containing 2, 3, or 4 –OH substituents are named diols, triols, and tetrols
28Properties of Alcohols Capable of intermolecular hydrogen bondingHigher boiling points than alkanes & halocarbons containing comparable numbersAlcohols up to 4 carbon atoms are soluble in waterSolubility with 4 carbons or more is much lowerCarbon chain is nonpolar (not attracted to water)…more carbons = more nonpolar parts to the moleculeHydroxyl part is polar…that’s why small alcohols are soluble in water
29Uses of Alcohols Common Name: Isopropyl Alcohol IUPAC Name: Rubbing alcoholBase for perfumes, creams & lotionsCommon Name: Ethylene glycolIUPAC Name:Main ingredient in antifreezeSoluble in waterFreezes at -17.4CCommon Name: EthanolIUPAC Name:Alcoholic BeveragesA depressantIn industry: denatured alcohol
30Aldehydes An organic compound in which the carbon of the carbonyl group is always joined to at leastone hydrogenCarbonyl Group: a CO group
31Ketones An organic compound in which the carbon of the carbonyl group is joined to two othercarbons
32Naming Aldehydes & Ketones Identify the longest hydrocarbon chain containing the functional group2. For aldehydes, replace the –e of the hydrocarbon with –al3. For ketones, replace the –e of the hydrocarbon with –one4. If the functional group can occur at more than one place, designate its position with the lowest possible number.
33Properties of Aldehydes & Ketones Form weak hydrogen bonds between the carbonyl oxygen and the hydrogen atoms of waterLow molar mass compounds are soluble in waterAbove 5 or 6 carbon atoms, solubility is lowSoluble in nonpolar solventsBoiling points are lower than alcoholsBoiling points are higher than alkanesBecause of polar ends they can have polar-polar interactionsTypically liquids or solids at room temperature
34Uses of Aldehydes & Ketones High molar mass aldehydes & ketones have fragrant or penetrating odorsAromatic aldehydes often used as flavoring agentsAlmond odor (benzaldehyde) & Cinnamon odor (cinnamonaldehyde)Formaldehyde (methanal)Acetone (propanone)Solvent for plastics, nail polish removers, etc.
35Esters Contain a carbonyl group and an ether link (C-O-C) to the carbonyl group
36Properties of Esters Uses of Esters Pleasant, fruity odors Give blueberries, pineapples, apples, pears, bananas and many other fruits their characteristic odorsGive many perfumes their fragrances