IB Organic Chemistry

Organic – What is it? Originally defined as the chemistry of all living things Now defined as the chemistry of carbon and its compounds Includes All biological molecules Fossil fuels Most synthetic materials plastics

Homologous Series There are so many organic molecules that we need a classification system Homologous series : a family of like organic molecules Members of the series have differing numbers of carbon atoms Have similar characteristics and functional groups

Series: Alkanes Carbon chains that have only single bonds Saturated hydrocarbons Name ends in -ane CnH2n+2 CH4 Methane C2H6 Ethane C3H8 Propane C4H10 Butane C5H12 Pentane

Naming: IUPAC This identifies the stem or root of the name International Union of Pure and Applied Chemistry Number of Carbons Stem for IUPAC name 1 meth- 2 eth- 3 prop- 4 but- 5 pent- 6 hex- Rule 1: Identify the longest straight or continuous chain of carbon atoms This identifies the stem or root of the name

Examples ethane methane hexane

Naming: IUPAC Rule 2: add a suffix based on the type of chain Type Alkane -ane Alkene -ene Alkyne -yne Rule 2: add a suffix based on the type of chain Alkanes have single bonds Alkenes have double bonds Alkynes have triple bonds The location of the double or triple bonds need to be specified

Examples 1-propyne propane 1-propene 2-butene

Naming: IUPAC Rule 3: Name the side chains as the prefix of the name (label the carbon that it is located on) Number of Carbons Branch name 1 methyl- 2 ethyl- 3 propyl- 4 butyl- 5 pentyl- 6 hexyl-

Examples 2-methylhexane 3-ethyl, 3-methylpentane

Series: Alkenes Carbon chains that contain a double bond Unsaturated hydrocarbons Name ends in -ene CnH2n C2H4 Ethene C3H6 Propene C4H8 1-Butene C5H10 1-Pentene

Series: Alkynes Carbon chains that contain a triple bond Unsaturated hydrocarbons Name ends in -yne CnH2n-2 C2H2 Ethyne C3H4 Propyne C4H6 1-Butyne C5H8 1-Pentyne

Functional Groups Alcohol Aldehyde Ketone Carboxylic acid Ester Halide Groups attached to the carbon framework that give the molecule certain characteristics Alcohol Aldehyde Ketone Carboxylic acid Ester Halide

R-OH Series: Alcohols Functional Group: hydroxyl group, -OH Name ends in -ol CH3OH Methanol CH3CH2OH Ethanol CH3CH2CH2OH 1-Propanol R-OH

Series: Carboxylic acids Functional Group: carboxyl group, -COOH Name ends in –oic acid No numbers needed! HCOOH Methanoic acid CH3COOH Ethanoic acid CH3CH2COOH Propanoic acid R-COOH

R-CHO Series: Aldehyde Functional Group: carbonyl group Name ends in -al H No numbers needed! CH2O Methanal CH3CHO Ethanal CH3CH2CHO Propanal R-CHO

Series: Ketone Functional Group: carbonyl group Name ends in -one Numbers needed when > 4 carbons CH3COCH3 Propanone CH3COCH2CH3 Butanone

R-COOR Series: Esters Functional Group: -COOR Name ends in –oate Propyl ethanoate CH3COOCH3 Methyl ethanoate CH3COOCH2CH3 Ethyl ethanoate CH3CH2COOCH3 Methyl propanoate CH3CH2COOCH2CH3 Ethyl propanoate R-COOR

R-X Series: Halides Functional Group: presence of halogen Name – suffix stays the same CH3CH2CH2Cl 1-chloropropane R-X

C2H5 C4H10 CH3CH2CH2CH3 Types of Formulas Empirical Molecular (simplest ratio) Molecular Full Structural Condensed Structural Line formula C4H10 CH3CH2CH2CH3

Naming: IUPAC This identifies the stem of the name International Union of Pure and Applied Chemistry Number of Carbons Stem for IUPAC name 1 meth- 2 eth- 3 prop- 4 but- 5 pent- 6 hex- Rule 1: Identify the longest straight or continuous chain of carbon atoms This identifies the stem of the name

Naming: IUPAC Rule 2: Use the functional group ending as the suffix of the name (-ane, -ene, -yne, -ol, -al, -one, -oic acid, -oate) Side chain Prefix -CH3 methyl -C2H5 ethyl -C3H7 propyl -F, -Br, -I, -Cl fluoro-, chloro-, iodo-, bromo- -NH2 amino- -OH hydroxy- Rule 3: Name the side chains as the prefix of the name (label the carbon that it is located on)

ID ONLY O CH3-O-CH2-CH3 methoxyethane (ether) CH3—CH2—NH2 ethylamine (amine) CH3—CH2—C—NH2 Propanamide (amide) O

Review Activity Part I Part II Part III Come up with 10 names and 10 structures…. Place them in random order Part II Switch papers with someone else and solve Part III Check each others answers Check another group’s answers if time…

Rings Add the word cyclo- to the stem Examples cyclopropane cyclobutane cyclopentane cyclohexane

Aromatic Molecules Contain the benzene ring Unsaturated cyclohexene

Isomers C4H10 Molecules that have the same kinds and numbers of atoms, but different arrangements 2-methylpropane butane CH3CHCH3 CH3CH2CH2CH3 CH3

Cis-Trans Isomers Alkenes Rotation at c-c double bonds restricted cis = same side of double bond trans = opposite sides

Primary, Secondary, & Tertiary Primary carbon atoms: attached to functional group and 1 other carbon Secondary carbon atoms: attached to the functional group and 2 carbons Tertiary carbon atoms: attached to functional group and 3 other carbons

Activity Determine the strongest IMF present for: Alcohols halides Ketones Aldehydes C. acids alkanes Determine the polarity. (high/medium/low) Cut out and arrange your pieces by physical properties…

Physical Properties Boiling point: As the carbon chain lengthens, the boiling point increases Solubility: Length of hydrocarbon chain: chains are nonpolar Solubility decreases as chain increases Functional group: ability to form hydrogen bonds and interact with water Alcohols, aldehydes, ketones, and carboxylic acids soluble Halogenalkanes are not soluble in water

Halogenoalkanes… Very slightly soluble in water. Only slightly polar Do not effectively break the hydrogen bonds between water molecules. Soluble in nonpolar or less polar organic solvents such as alcohol and benzene .

Physical Properties Volatility: ease of changing into the gaseous state Chain length: As the chain increases, the boiling point increases: Smaller chains likely to be gases or liquids Larger chains likely to be solids

Physical Properties Volatility Branching of the chain: more branches = more space around the molecule = weaker IMFs = lower boiling points Functional groups: Polar groups have higher boiling points- stronger intermolecular forces- harder to break apart

Most volatile Least volatile Aldehyde Alkane Alcohol Ketone Halogenoalkane Aldehyde Ketone Alcohol Carboxylic acid Increasing boiling points Increasing strength of intermolecular attraction

Alkane Reactivity Low reactivity! C-C and C-H bonds are very strong Combustion Complete produces carbon dioxide and water Incomplete  limited oxygen – new products formed Carbon monoxide (limited oxygen) Carbon (extremely limited oxygen)

Alkane Combustion Carbon dioxide – greenhouse gas Water – greenhouse gas (absorb radiation and contribute to global warming) Carbon monoxide – toxic to us (absorbed by the body and bonds to hemoglobin preventing oxygen from being carried) Carbon – particulates formed in the air, and is harmful to respiratory system

Cl2 + CH4  CH3Cl + HCl Alkane Reactivity Substitution reactions – main type of reaction alkanes undergo An incoming species takes the place of a H atom Often called free radical substitutions Cl2 + CH4  CH3Cl + HCl

Three Basic Steps in a Free Radical Mechanism Chain initiation- The chain is initiated by UV light breaking a chlorine molecule into free radicals. Cl2  2Cl. 39

Homolytic Fission Free radicals are formed if a bond splits evenly - each atom getting one of the two electrons. The name given to this is homolytic fission. 40

Three Basic Steps in a Free Radical Mechanism Chain propagation reactions- These are the reactions which keep the chain going Have to have free radicals in the system to keep the chain going CH4  +  Cl.  CH3.  +  HCl CH3.  +  Cl2  CH3Cl  +  Cl . 41

Three Basic Steps in a Free Radical Mechanism Chain termination reactions These are reactions which remove free radicals from the system without replacing them by new ones – terminating the rxn 2 Cl.  Cl2 CH3. + Cl.  CH3Cl CH3. + CH3.  CH3CH3 42

+ H2  Alkene Addition Rxns Moves from unsaturated to saturated Hydrogenation – addition of hydrogen on the double bond Margarine is solid at room temperature because it has been hydrogenated and is saturated (higher melting points) + H2 

+ Br2  Alkene Addition Rxns Halogenation: occur at room temperature Accompanied by the loss of color of the reacting halogen + Br2 

+ HBr  Alkene Addition Rxns Hydrohalogenation: occur at room temperature + HBr 

+ H2O  Alkene Addition Rxns Hydration Addition of water turns the alkene into an alcohol Water splits into H and OH + H2O 

+ H2O  Markovnikov’s Rule Hydrogens add to the carbon that has the most hydrogens already! + H2O 

Polymers Types of synthetic and natural polymers.

Polymerization of Alkenes Alkene acts as the monomer (building block of a polymer) Plastics are polymers of alkenes polyethene polypropene

Polymerization of Alkenes -PVC Polymerization of chloroethene into polychloroethene aka: PVC (polyvinylchloride)

Polymer Recycling Codes Common household polymers

Polymers The number code indicates the polymer type

Alcohols 2CH3OH(l) + 3O2(g) 2CO2(g) + 4H2O(g) Increased solubility in water CnH2n+1OH Oxidation: Complete oxidation: combustion reactions Potassium Dichromate (VI) 2CH3OH(l) + 3O2(g) 2CO2(g) + 4H2O(g)

Alcohols O and heat can be added to oxidize the OH group (in the form of Potassium dichromate VI) Primary alcohols-oxidized to carboxylic acids 2ndary alcohols- oxidized to ketones Tertiary alcohols- NR

Oxidation Alcohols are oxidized to alkanals (aldehydes) or alkanones (ketones)

Oxidation: Primary Alcohols Oxidizing agent: Potassium dichromate VI Ethanol is oxidized to ethanal Can be further oxidized to ethanoic acid Wine left exposed to air starts to smell of vinegar – this is the ethanoic acid

Oxidation: Secondary Alcohols Propanol oxidized to propanone

Oxidation: Tertiary Alcohols There is no hydrogen attached to the tertiary carbon. It is not possible for the tertiary acid to have a carbonyl group attached.

Primary Halogenoalkanes SN2 Mechanism Substitution nucleophilic bimolecular Bimolecular: depends on the concentration of both reactants (halogenoalkane and –OH)

Tertiary Halogenoalkanes SN1 Mechanism Substitution nucleophilic unimolecular Depends only on the concentration of the halogenoalkane Steric hindrance caused by three alkyl groups around carbon Bulky groups makes it difficult for an incoming group to attack the carbon atom

Tertiary Halogenoalkanes SN1 Mechanism Both reactions involve heterolytic fission of C-Cl bond

Secondary Halogenoalkanes mechanisms Secondary halogenoalkanes undergo a mixtures of SN1 and SN2 reactions, depending on reaction conditions

M&D questions The structures of morphine and diamorphine (heroin) are shown in Table 20 of the Data Booklet. State the name of a functional group present in diamorphine (heroin) but not in morphine.

State the differences between the structures of morphine and diamorphine (heroin). State the names of all functional groups in the molecule of morphine.

Examples of strong analgesics are morphine, codeine and diamorphine (heroin). Their structures are shown in Table 20 of the Data Booklet. (i) Identify two functional groups present in all three of these analgesics. (ii) Identify one functional group present in morphine, but not in diamorphine.

Identify two functional groups present in the side chain (R) of ampicillin by comparing its structure to that of penicillin in Table 20 in the Data Booklet.

ID ONLY O CH3-O-CH2-CH3 methoxyethane (ether) CH3—CH2—NH2 ethylamine (amine) CH3—CH2—C—NH2 Propanamide (amide) O

Objective: SWBAT demonstrate their knowledge of organic chemistry Warm up: What is a homologous series? Quiz today

Foldable… You need 5 sheets of paper Separate them by about ½ to 1 inch Fold and staple Labels: Title: Homologous Series Alkanes - Ketones Alkenes - Carboxylic acids Alkynes - Esters Alcohols - Halides Aldehydes