Presentation on theme: "Chapter 23: Organic Chemistry, Polymers, and Biochemicals"— Presentation transcript:
1 Chapter 23: Organic Chemistry, Polymers, and Biochemicals Chemistry: The Molecular Nature of Matter, 6EJespersen/Brady/Hyslop
2 Carbon Chemistry Bonding Strong covalent bonding to itself and to other non- metal elementsCapable of forming extremely long carbon-carbon chainsMultiple arrangements ofidentical molecular formulaslead to numerous isomers.
3 Structural Formula Representations Lewis Structure of PentaneCondensed Structural FormulaCH3CH2CH2CH2CH3 pentane
4 Structural Formula Representations Lewis Structure of Pentan-1-olCondensed Structural FormulaCH3CH2CH2CH2CH2OH 1-pentanol
5 Chiral Isomers of Carbon Chirality exists when carbon has four unique constituents bond to itself|Non-superimposable mirror images
15 Learning Check 1. Write the abbreviated structure for benzoic acid. 2. What family does C6H5NH2 belong to?amine family
16 Your Turn! Which of the following is an example of an ester? CH3CH2CH2OHB.C.D.
17 Hydrocarbons Hydrocarbon compounds only contain C and H Alkanes CnH2n CH3CH2CH3 propaneAlkenes CnH2n CH3CHCH2 propeneAlkynes CnH2n-2 CH3CCH propyneAromatic C6H benzeneCharacterized by cyclic delocalized π bonding
18 Hydrocarbons Alkanes are defined as saturated compounds. All singles bond to carbonCannot add more hydrogen atomsAlkenes and alkynes are unsaturated compounds.Alkenes have double bonds and H atoms can be added to the double bond to create a saturated compound.Alkynes have triple bonds and H atoms can be added to create a saturated compound.CH2=CHCH3 + H CH3CH2CH3
19 AromaticityCharacterized by conjugated bonds in a ring such as benzene.π electrons are delocalized over the ringLeads to greater stability than expectedProperties are different than those of other hydrocarbon familiesPolycyclic examples:
20 Hydrocarbon Nomenclature Rules for naming alkanes Established by IUPAC 1. Name ends in “-ane” 2. Complete name uses that of parent compound with constituent groups added. 3. Parent is longest continuous carbon chain. 4. Name of longest chain based on the number of carbons. 5. Carbon atoms are numbered starting at the end that gives the lowest number for the first branch.
22 Alkyl GroupsAlkane type groups added to parent chain are known as alkyl groups. Consist of alkane, minus one H atom. Name always ends in –ylExampleCH4 : now remove one H which yields –CH3Naming of –CH3Start with parent name, which is methaneDrop –ane and add –ylSo methane becomes methyl group
23 Alkyl GroupsCH3CH2CH3 yields –CH2CH2CH3 when one H atom is removed from the end carbon.The name of the aryl group is propyl.Note, you can have another isomer of propyl.The other isomer’s aryl group is 1-methylethyl, or isopropyl, and is created when the H atom is removed from the non-terminal carbon.
24 Nomenclature6. Aryl groups names are prefixed to parent name. 7. Multiple aryl groups on a parent are numbered and named alphabetically. 8. When there are multiple identical groups add di, tri, tetra to the aryl name. 9. If multiple, identical aryl groups are attached to the same carbon repeat the carbon number.
25 Examples What is the name of the compound shown? The longest carbon chain (parent) is four. Parent name is butane.Start numbering from the left to get the smallest number for the attached group.
26 Examples 3. The attached alkyl group is a methyl group. Thus, the correct name is:2-methylbutaneWhat is the name of the following compound?
27 Examples The parent chain contains five carbons. Thus, the parent name is pentane.Number from the left to obtain the smallest number for the first alkyl group.The alkyl groups are at the 2 and 3 positions.The 2 and 3 positions each contain a methyl group.
28 Examples Thus, the correct name is: 2,3-dimethylpentane Let’s consider an alkane with two substituents on the same carbon.
29 Examples The parent chain is six carbons long. The lowest correct numbering of positions is shown below.There are methyl and ethyl groups attached to carbon 3.
30 ExamplesThe correct name is:3-ethyl-3-methylhexane
31 Your Turn! What is the correct name for the molecule shown below? A. 3-butylpentaneB. 1,1-diethylpentaneC. 3-ethylheptaneD. 5-ethylheptane
32 Your Turn! What is the name of the compound shown below? A. 3-methyl-3-methyloctaneB. 3,3-dimethyloctaneC. 2-ethyl-2-methylheptaneD. 6,6-dimethyloctane
33 Chemical Properties of Alkanes Alkanes are relatively unreactiveNot reactive in conc. NaOH or H2SO4 at room temperature.React with hot HNO3Will react with Cl2 and Br2 to form halogenated hydrocarbons.Examples are CH3Cl, CH2Cl2 and CHCl3Can crack molecules like ethane under controlled conditions to form CH2CH2Will react with O2 to form CO2, CO, and H2O
34 Alkenes and Alkynes Alkenes contain one or more double bonds General form: CnH2nAlkynes contain one or more triple bondsGeneral form: CnH2n-2Non-polar compounds are not water solubleExamples:Ethene or ethyleneEthyne or acetylene
35 Alkenes and Alkynes Nomenclature The parent chain must contain the multiple bond even if it is a smaller chain length than one without a multiple bondNumber from end that gives the lowest number to the first carbon of the multiple bondThe number is given as -x- and placed just before the –ene or –yne of the parent name.For example, but-2-ene. The double bond starts on carbon 2 of the chain.
36 Alkene ExamplesStart numbering from the left to get the lowest number for the first carbon with the double bondThe parent is heptene and the correct naming including the double bond location would be hep-2-ene
37 Alkene Example The parent chain is four carbons 2,3-dimethylbut-2-ene We would not name this 2-methyl-3- methylbut-2-ene
38 Naming Polyenes How do we name compounds such as the following? This compound contains two double bonds and is known as a dieneWe want the lowest number for the first carbon of each of the double bondsStart numbering from the right
39 Naming Polyenes The correct name would be hex-1,3-diene Three double bonds would be a trienehex-1,3,5-triene
40 Cyclic AlkenesNumber ring to obtain lowest number for first carbon of the double bond
41 Cyclic Alkenes Correct name is 1,6-dimethylcyclohex-1-ene Other ring examplesCyclopenteneCyclooctene
42 Your Turn! What is the correct name for the compound shown below? A. 1,4-dimethylcyclopent-1-eneB. 1,3-dimethylcyclopent-1-eneC. 1-methyl-4-methylcyclopent-1-eneD. 1,3-dimethylcyclo-1-pentene
43 Your Turn!What is the correct structure for 3,3-dimethylpro-1-ene?A.B.C.D.
44 trans-1,2-dibromoethene Geometric IsomersGroups cannot freely rotate about a double bondTherefore, it is possible to have geometric isomersExamples:trans-1,2-dibromoethenecis-1,2-dibromoethene
45 Reactions of Alkene Alkenes readily add across the double bond Examples of an addition reaction:CH2CH2 + H CH3CH3 hydrogenationCH2CH HCl → CH3CH2ClCH2CH H2O → CH3CH2OHCH2CH Cl2 → CH2ClCH2Cl
46 Aromatic Hydrocarbons The most common aromatic compound is benzene and its derivativesRepresentation of bondingDelocalized π bonds create unique stability, called resonance stabilization. The circle in the ring represents delocalization.
47 ReactionsSubstitution reactions maintain benzene’s resonance structure.Addition reactions, like those of alkenes, destroy resonance structureSubstitution reaction:
48 Addition ReactionNotice that you have reduced the double bonding in the ring and altered the resonance stabilization of the ring
49 Learning Check: What product would form if benzene reacted with nitric acid using an appropriate catalyst?Sulfuric acid is the catalystA substitution reaction occurs
50 Your Turn! Which product is most likely formed when sulfuric acid reacts with benzene?A. B.C. D.
51 Organic Compounds Containing Oxygen Important functional groups:AlcoholEtherAldehydeKetoneCarboxylic acidEster
52 Alcohols and Ethers Common alcohols: names end in –ol CH3OH methanol CH3CH2OH ethanolCH3CH2CH2OH propan-1-olIf the –OH group was attached to the central carbon then the alcohol would be propan-2-olAlcohols form hydrogen bonds, causing their boiling points to be higher than predicted.
53 Alcohols and Ethers Primary alcohols: Secondary alcohols: Tertiary alcohols:
54 Alcohols and Ethers Common ethers: CH3OCH3 dimethyl ether CH3CH2OCH2CH3 diethyl etherCH3OCH2CH3 methyl ethyl etherNo hydrogen bonding occurs, thus, boiling points are lower than corresponding alcoholsLike alkanes, ethers are not very reactive
55 Reactions of AlcoholsAlcohols can undergo oxidation to form a variety of products. Oxidation removes an H atom from the alcoholic carbon as well as the H on the –OH group.Primary alcohols can be oxidized to aldehydes and carboxylic acids
56 Reactions of AlcoholsAldehydes are more readily oxidized than alcoholsSecondary alcohols can be oxidized to ketones
57 Reactions of Alcohols Ketones are not further oxidized Tertiary alcohols have no H atom on the alcoholic carbon and thus, do not undergo oxidationAlcohols undergo elimination reactions in the presence of concentrated H2SO4 forming water and alkenes–OH group readily accepts a proton from sulfuric acid
58 Elimination Reaction Dehydration of an alcohol During the reaction a very unstable carbocation is formed. This ion eliminates a proton to form the alkene.
59 Substitution Reactions of Alcohols Using heat and concentrated HBr, HI, or HCl, a halogen will replace the –OH groupA proton adds to the –OH forming –OH2+Water leaves and the halogen ion attaches to the carbon site where the –OH was attached2-bromo-2-methylpropane
60 Aldehydes and Ketones Naming aldehydes Parent name ends in –al, replacing –e in the alkane nameThe aldehyde group is always at the end of a chain and numbering starts with that end of the chainAldehyde groupKeto group
61 Naming Aldehydes Number from the aldehyde end Do not use -1- for aldehyde:3-methylpropan-1-al, or 3-methyl-1-propanal would be wrong3-methylpentanal
62 Learning Check What is the name of the following aldehyde? 4-ethylhexanal
63 Naming Ketones Parent name ends in –one Parent chain must contain carbonyl groupNumbering so carbonyl carbon has lowest possible number4-ethylheptan-3-oneNOT: 4-ethylheptan-5-one
64 Your Turn! What is the correct name for the aldehyde shown below? A. 2,4-dimethylpentanalB. 2,4-dimethyl-1-pentanalC. 2-methyl-4-methylpropanalD. 2,4-dimethyl-5-pentanal
65 Your Turn! - SolutionAldehydes are numbered from the aldehyde end of the moleculeThere are two identical groups, (methyl) so we use –di in the naming2,4-dimethylpentanal
66 Your Turn! What is the correct name for the ketone shown below? A. 4-methyl-3-ethylhexan-2-oneB. 4-ethyl-3-methylhexan-5-oneC. 3-ethyl-4-methylhexan-2-oneD. 3,4-diethylpentan-2-one
67 Your Turn! - SolutionNumber to give lowest number to keto group so you start from the rightAlkyl groups are ordered alphabetically so ethyl comes before methyl
68 Reactions of Aldehydes and Ketones Aldehydes and ketones add hydrogen across the C=O bondProcess is hydrogenation or reduction
72 Naming Esters Name begins with alkyl group attached to the –O Name of parent acid is separate from the alkyl group name and –oic is replaced with –ateEthyl propanate
73 Learning Check What is the name of the following ester? Alkyl group is propylNumber, starting withthe ester carbonPropyl 4-methylpentanate
74 Your Turn!What is the correct name for the product when 3- methylbutan-1-ol is completely oxidized? A. 3-methylbutanoic acid B. 2-methyl-1-butanoic acid C. 2-methlybutan-1-oic acid D. 3-methylbutan-1-oic acid
75 Reactions of Carboxylic Acids The –COOH is weakly acidic and therefore reacts with baseRCOOH + OH– → RCOO– + H2O
76 Formation of EstersEsters give fruits their characteristic odor
77 SaponificationStrong base reacts with an ester to form alcohol and the ester’s anion formspentanoate ion
78 Your Turn!Name the ester formed when methanol reacts with hexanoic acid. A. 1-methyl hexanoate B. methylhexanoate C. methyl hexanoate D. methyl hexan-1-oate
79 Organic Derivatives of Ammonia Amines are derived from ammonia with one or more H atoms replaced with organic groupsLike ammonia, amines are weakly basicAmines react with acids
80 Acid Property of Protonated Amines Ethylmethylammonium ion is the conjugate acid of ethylmethylaminepKa = pKb= 3.24
81 AmidesGeneral formWhere (H)R indicates either an H atom or an R group attachedNamingThe name of the parent acid is amended dropping the –oic ending and replacing it with –amide
82 Example Names of Amides Propanamide4-ethylhexamideThese are examplesof simple amides
83 Synthesis of Simple Amides An organic acid reacts with aqueous NH3 to form an amide2-methylpropanoic acid yields 2-methylpropanamide
84 Amide ReactionsAmides can be hydrolyzed back to their acid form producing ammonia in the process
85 Amide ReactionsUrea, an amide, ultimately hydrolyzes to NH3, CO2 and waterCarbonic acid is formed, which then decomposes to carbon dioxide and waterThe overall reaction is:
86 Basicity of Amides Amides are not basic like amines The lone pair on the N atom is delocalized and thus not readily available for donation to a protonAmides are neutral in an acid-base sense
87 Your Turn! What is the correct name for the molecule shown below? A. 4,5-dimethylhexanamideB. 2,3-dimethyl-6-hexanamideC. 4-methyl-5-methylhexanamideD. 4-isopropyl-4-methylpropanamide
88 Organic Polymers Macromolecule made up of small, repeating units Example, polypropyleneStarting material
89 Polymers Repeating unit is called a monomer The reaction to create a polymer is known as polymerizationChain Growth PolymersPolymers created by the addition of one monomer to another monomerPolypropylene is an example of a chain growth polymer
91 General Repeat Unit for Polyvinyl Chloride This unit is repeated n times to create the polymer
92 Step-Growth Polymers Condensation reaction A small molecule such as water is eliminated when the monomers are joined: Nylon 6,6, for exampleNylon is a copolymer, two different molecules combined
93 Dacron-A PolyesterAnother example of a condensation copolymer
94 Physical Properties Dependent on how polymers pack Branching polymers create non-crystalline, amorphous solids
95 Physical PropertiesAmorphous polymer of polyethylene is known as low density polyethelene or LDPELow molecular mass and low structural strengthUsed to make plastic grocery bagsNon-branching polyethylene forms high density polyethylene or HDPEStrong London forces between chainsStrong fibers are formed
96 Physical PropertiesHDPE is lightweight, water repellent, resists tearsCommon usesStrong mailing envelopesTyvekUltrahigh molecular weight polyethlene3 to 6 million molar massUHMWPEUsed to make very strong polymersSails, bullet proof vests, bike helmets
97 Biochemical molecules CarbohydratesStructures of glucose, a monosaccharideBuilding unit for cellulose and starch
99 Disaccharide Reactions Disaccharide molecules split into monosaccharidesGal-O-Glu + H2O → galactose + glucosePolysaccharidesStarch is a large polymeric sugar moleculeCan be broken down into glucose, which is used for energy in biochemical reactionsAmylose is the structurally simpler glucose polymer portion of starch
100 Disaccharide Reactions AmyloseAmylose +n H2O → n glucose
101 PolysaccharidesThe majority of starch is made up of a more complex polysaccharide known as amylopectin
102 CelluloseA polymer of glucose with different oxygen bridge orientationsWe lack an enzyme to digest cellulose
103 Lipids Water insoluble natural products Dissolve in non-polar solvents Relatively non-polar with large segments that are hydrocarbon-likeCholesterol
104 LipidsFats and oilsTriacylglycerols-esters of glycerol and long chain carboxylic acids (fatty acids)
107 Reactions of Triacylclycerols DigestionBreaks down the triacylclycerol into its three component fatty acids and glycerol. Takes place in base so in fact the fatty acids are in their anion formHydrogenationThe addition of hydrogen to the double bondsTurns oils into solids
108 Soap Castile soap is made from olive oil Olive oil has many different fatty acidsTwo major fatty acid constituents are oleic acid, %, and linoleic acid, 4-20%Saponification of triacylglcerols using NaOH or other base, and heat, results in salts of the fatty acid components plus glycerolSodium oleate and sodium linoleate, for exampleThis product mixture, soap, is thus the result of saponification of triacylglcerols
109 Cell Membranes Glycerophospholipids Diacylclcerols with phosphate unit which is attached to a amino alcohol unitContain a hydrophobic, water avoiding, unit and a hydrophilic, water loving, unitAggregate together to form lipid bilayers with hydrophilic layers oriented to the outside and inside layers of the membrane
111 Cell MembranesMembrane also contains protein units, some which act as ion channels to move select ions in and out of cellsOther proteins act as molecular recognition sites for hormones and neurotransmitters
112 Proteins Polypeptides made up of α-amino acids Serve as hormones, neurotransmitters, and enzymesEssential amino acids are those the body does not synthesizeBasic amino acidstructure:
116 Polypeptides Combining two amino acids forms a dipeptide Often the amino acids are abbreviatedGlycine – GlyAlanine – AlaA dipeptide of these would then be shown as:Gly-AlaA few amino acids can be arranged in a very large number of orders leading to many different proteinsGly-Ala-Arg Gly-Arg-Ala Ala-Gly-ArgPlus three more
117 Polypeptides and Proteins How many ways can you arrange n different objects?n ! Therefore 3 amino acids have 6 arrangementsYou can also use the same amino acid more than once in a polypeptideProteinsConsist of polypeptides and usually small organic moleculesThey may also incorporate metal ions into their structure
121 Basic Nucleic Acid Structure Where G is a placeholder for a unique nucleic acid side chainThe sugars are ribose for RNA and deoxyribose for DNAThe groups, G, are:adenine (A), thymine (T), uracil (U), guanine (G), and cytosine(C)
122 DNA - Double Helix Structure A unique arrangement of amino acids maximized hydrogen bonding resulting in a pairing of strands to form a double helixBase Pairing A only with TC only with G
123 DNA Replication Enzyme catalyzed process unzips the two strands Arrangement of base pairs dictates replication pattern
124 Polypetide SynthesisControlled formation of peptide bonds to make a polypeptideRepeated many times to form polypeptides and proteinsGenetic information is transcribed from DNA in the nucleus onto RNA (m RNA)This messenger RNA moves outside the nucleus and through a complex process, using other RNA types, synthesizes a specific proteinThe order of amino acid synthesis is coded so that the correct amino acids are made available in the proper sequence