2Organic ChemistryOrganic Chemistry is the chemistry of carbon containing moleculesOriginally thought to be produced only by living things… organicChemistry is the study of the composition, structure and reactions of matterThe Structure of molecules is very important in organic and biochemistry
3IUPAC Names: Organic Molecule Prefixes The names of organic compounds are determined by the IUPAC rules (International Union of Pure and Applied Chemistry). The stem of the name states the number of carbon atoms in the carbon chain of the compounds. The suffix, in this case –ane, indicates the alkane family.
4Structural Formulas Revisited Alkanes are written as structural formulas:Revisit Chapter 6 for more detailsExpanded Structure shows each bondCondensed Structures show each carbon atom and the attached hydrogen atomsIn methane, CH4 the four valence electrons of carbon are shared with the single electrons of four hydrogen (H) atoms. Each pair of electrons is a single bond, which can be drawn as a line. When a structure is drawn to show each bond, it is called a complete structural formula.
5Drawing Structural (Line) Formulas Carbon atoms in a chain:maintain their tetrahedral shapeare connected in a zigzag patternare drawn as two dimensionalcan be written in many wayshave free rotation in straight chain
6ConformersRemember, organic compounds have free rotation around sp3 carbon atoms, this leads to a variety of spatial orientations for the same structureConformers: different orientations of the same molecule:
7ConformersLet’s consider different conformers of pentane, C5H12:
8IsomersIsomers:Compounds with the same molecular formula but different atomic arrangementsFor Example:Butane (C4H10) has a straight chain and a branched chain form
9IsomersLet’s consider different isomers of pentane, C5H12:
10Alkanes with Substituents In the IUPAC system:a carbon branch is named an alkyl-grouphalogen atoms are named as halo-group
11Naming Alkanes Find longest alkane chain Name and number substituents Substituents are numbers to give the lowest number possibleSubstituents are named in alphabetical order, ignore prefixes di-, tri-, etc…
13Learning Check Provide the IUPAC name for the following: Cl CH3 | | | |CH3─CH2─CH─CH2─C─CH2─CH3|Cl
14Drawing Alkanes from Names 2,2,3-trimethylpentane 2,4-dibromo-3-ethylhexane
15Take Home Draw the condensed and line structure for 2-bromo-4-chlorobutane.
16Classifying Carbon Atoms Primary (1°): attached to one other carbon Secondary (2°): attached to two other carbons Tertiary (3°): attached to three other carbons Quaternary (4°): attached to four other carbons
17Cycloalkanes Saturated compounds with a ring structure Have a loss of free rotationFormed by removal of a H atom form each end carbonButane, C4H10Cyclobutane, C4H8
18CycloalkanesSaturated compounds with a ring structure that have a loss of free rotationPractice drawing cyclohexane, C6H12
19Unsaturated Hydrocarbons Alkenes contain a carbon-carbon double bond (C = C)Have a fixed structure around the C=CNamed for the longest carbon chain which includes the base alkeneAlkynes contain a carbon-carbon triple bond (C ≡ C)Named for the longest carbon chain which includes the base alkyne
21cis and trans Isomers of Alkenes Alkenes have two different isomers that are determined by what groups lie on each side of the double bond:cis: substituent groups are on the same side of the double bondtrans: substituent groups are on the opposite side of the double bondMUST have two different groups on C
23AlkynesNO rotation around the C≡C and have a straight line structure at the triple bond:EXAMPLE:
24Reactions of Alkenes Addition Reactions (Combination Reactions): Reactants add across the double bondH2 (hydrogenation) and halogens (F2, Br2, Cl2)+ 3 H2
25Reactions of Alkenes Addition Reactions (combination reactions) HF, HCl, HBr, HIH2O, creates an alcohol+ HCl+ H2O
26Polymerization of Alkenes Polymerization is an Addition Reaction:Addition reaction where one alkene combines with another alkenePolymer: A molecule with a high molar mass made up of thousands of repeating units.Monomer: individual molecules used to produce the polymer.
28PolymerizationIn polymerization, small repeating units called monomers join to form a long-chain polymer
29Learning CheckWhat is the structure of polypropylene?
30Take HomeWhat is the structure of polystyrene (polyphenylethene)?
31Recycling PlasticsRecycling is simplified by using codes found on plastic items:
32Reactions of AlkynesAlkynes react very similarly to alkenes but often can add two moles of reactant per mole of alkyne (due to triple bond)
33Aromatic Compounds Benzene (C6H6): has six electrons shared equally among six carbon atoms in a ringis written as two possible ring structuresis also represented as a hexagon with a circle drawn inside (common line structure shorthand)
35Learning Check Select the correct name for the following structure: 1) chlorohexane2) chlorobenzene3) 1-chlorobenzene
36Learning CheckWrite the IUPAC name of the following compound:
37Take HomeDraw the condensed structural formula for 1-bromo-3,4-dichlorobenzene.
38Alcohols and EthersAn alcohol contains the hydroxyl (-OH) functional groupIn an ether, an oxygen atom is bonded to two carbon atoms
39Aldehydes and Ketones Contain a carbonyl group (C=O) In an aldehyde, the carbonyl group is attached to another carbon atom and one hydrogen atomIn a ketone, the carbonyl group attached to two other carbon atoms
40Oxidation Reactions In organic chemistry (and biochemistry): Oxidation Reactions typically involve the addition of bonds to oxygenReduction Reactions typically involves a gain of hydrogen
41Classification of Alcohols Alcohols are:classified by the number of carbon groups attached to the carbon atom bound to the -OH group:Primary Alcohol when one carbon group attachedSecondary Alcohols when two carbon groups are attachedTertiary Alcohols when three carbon groups are attached
42Classification of Alcohols Alcohols are:classified by the number of carbon groups attached to the carbon atom bound to the -OH group:
43Learning Check Classify the following as 1°, 2°, or 3° alcohols: OH │ CH3─CH2─CH2─OH B. CH3─CH─CH2─CH3C OHCH3─C─CH2─CH3CH3
44Oxidation of 1 Alcohols form Aldehydes In the oxidation [O] of a primary alcohol (1):one H is removed from the –OH groupanother H is removed from the C bonded to the –OHprimary alcohol aldehydeOH O│ ║CH3─C─H CH3─C─H + HOH│HEthanol Ethanal(ethyl alcohol) (acetaldehyde)
45Oxidation of 2 Alcohols The oxidation of 2 alcohols is similar, but a ketone is formed:secondary alcohol ketoneOH O│ ║CH3─C─CH CH3─C─CH HOH│H2-propanol(isopropanol)2-propanone(acetone)
46Oxidation of 3 Alcohols Tertiary (3) alcohols do not readily oxidize:Tertiary alcoholOH│CH3─C─CH no productCH3NO H on the C─OH to oxidize2-Methyl-2-propanol
47Oxidation of Ethanol in the Body Enzymes (proteins) in the liver oxidize ethanolthe aldehyde product impairs coordinationblood alcohol over 0.4% can be fatalO O║ ║CH3CH2OH CH3CH CH3COH CO2 + H2OEthanol Acetaldehyde Acetic acid
48Percent Blood Alcohol Concentration A breathalyzer test is used to determine blood level of ethanol
49Carboxylic Acids and Esters Both contain a carboxyl group, a carbonyl group attached to a hydroxyl groupA carboxylic acid contains a terminal carboxyl groupAn ester contains the carboxyl group between carbon atomsThe H on the hydroxyl is replaced by the C-C bond
50Amines and Amides Contain a nitrogen atom or nitrogen containing group In an amine, the functional group is a nitrogen atomIn amides, the hydroxyl group of a carboxylic acid is replaced by a nitrogen group