Presentation on theme: "CHAPTER 8 INTRODUCTION TO ORGANIC CHEMISTRY"— Presentation transcript:
1CHAPTER 8 INTRODUCTION TO ORGANIC CHEMISTRY BASIC CHEMISTRYCHM 138CHAPTER 8 INTRODUCTION TO ORGANIC CHEMISTRY
2ORGANIC CHEMISTRY Organic chemistry: The branch of chemistry that deals with carbons compounds.‘Organic’ – derived from living organismsStudy of compounds extracted from living organisms and their natural products.Examples: sugar, starch, urea, waxes, carbohydrates, fats and etcHuman are composed of organic molecules – proteins in skin, lipid in cell membranes, glycogen in livers and the DNA in the nuclei of cells.
3Chemistry of carbon:- Two stable isotops (13C and 12C)- electron configuration: 1s2 2s2 2p2- four valence electrons- can form more compounds than any other element- able to form single, double and triple carbon-carbon bonds, and to link up with each other in chains and ring structures
4HOMOLOGUE SERIES AND FUNCTIONAL GROUPS A group of atoms that is largely responsible for the chemical behavior of the parent molecule.Functional groups:- hydrocarbons- alcohols- aldehydes- ketones- carboxylic acids- alkyl halides
6ALKANES General formula: CnH2n+2, where n = 1, 2, …. Only single covalent bonds are presentKnown as saturated hydrocarbons because contain the maximum number of hydrogen atoms that can bond with the number of carbon atoms present.Can be assumed to be sp3-hydridized
8The melting and boiling points of the straight-chain isomers of the first 10 alkanes
9Homologous Series Definition: A series of compounds in which each member differs from the next by a specific number and kind of atoms.Alkanes: Differ only at number of (CH2)Series of compounds that has the same functional group.
10INITIAL NAMES OF THE HOMOLOGOUS SERIES Number of carbon atoms, nName1Meth2Eth3Prop4But5Pent6Hex7Hept8Oct9Non10Dec
11NAMING ALKANES Alkyl groups are used to name organic compounds. The general formula of an alkyl group is CnH2n+1.The letter “R” is often used in formulas to represent any of the possible alkyl groups.R= CnH2n+1 (any alkyl group)R = CH3 — methyl groupR = CH3CH2 — ethyl group
13IUPAC RULES International Union of Pure and Applied Chemistry RULE 1. Select the longest continuous chain of carbon atoms as the parent compound.Consider all alkyl groups attached to it as branch chains or substituents that have replaced hydrogen atoms of the parent hydrocarbon. If two chains of equal length are found, use the chain that has the larger number of substituents attached to it.The alkane’s name consists of the parent compound’s name prefixed by the names of the alkyl groups attached to it.
14This structure has 2 chains. This chain has 6 carbon atoms.123456This chain has 4 carbon atoms.1234
151 2 3 4 5 6 This is the longest continuous chain. Select this chain as the parent compound.123456
16123456This is a methyl group.It is a branch chain and can be considered to have replaced a hydrogen on the parent compound.
17The name of the compound is 3-methylhexane. 123456
18IUPAC RULESRULE 2. Number the carbon atoms in the parent carbon chain starting from the end closest to the first carbon atom that has an alkyl group substituted for a hydrogen atom.If the first subsitutent from each end is on the same-numbered carbon, go to the next substituent to determine which end of the the chain to start numbering.
19If the chain is numbered left to right, the isopropyl group is on carbon 5. 12537864isopropyl group
20If the chain is numbered right to left, the isopropyl group is on carbon 4. Use right to left numbering so that the isopropyl group is on the lowest numbered carbon.4-isopropyloctane87462135isopropyl group
215 4 2 1 3 2-isopropyl pentane IUPAC RULES RULE 3. Name each alkyl group and designate its position on the parent carbon chain by a number (e.g., 2-methyl means group attached to C-2).542132-isopropyl pentane
22The methyl group appears twice RULE 4. When the same alkyl-group branch chain appears more than once, indicate this repetition by a prefix (di-, tri-, tetra- and so forth) written in front of the alkyl group name (e.g. dimethyl indicates two methyl groups).–The numbers indicating the alkyl-group positions are separated by a command and followed by a hyphen and are placed in front of the name (e.g., 2,3-dimethyl).54213The methyl group appears twice2,3-dimethylpentane
23RULE 5. When several different alkyl groups are attached to the parent compound, list them in alphabetical order (e.g. ethyl before methyl in 3-ethyl-4-methyloctane). Prefixes are not included in alphabetical ordering (ethyl comes before dimethyl).
25Alkanes can have many different types of substituents. For example:
26CYCLIC HYDROCARBONSA hydrocarbon that contains carbon atoms joined to form a ring.Cycloalkanes – all carbons of the ring are saturated
27NOMENCLATURE OF CYCLOALKANES Similar to that alkanes. For examples:
28Three isomers of pentane (C5H12) ISOMERISATIONStructural isomers:Molecules that have the same molecular formula, but different structureThree isomers of pentane (C5H12)
29STRUCTURE ISOMERS FOR ALKANES NAMEMOLECULAR FORMULATOTAL OF ISOMERSMethaneCH41EthaneC2H6PropaneC3H8ButaneC4H102PentaneC5H123HexaneC6H145HeptaneC7H169OctaneC8H1818NonaneC9H2035DecaneC10H2275
30ALKENES Also called olefins Contain at least one carbon-carbon double bond (C=C)General formula, CnH2n (n=2,3,…)Classified as unsaturated hydrocarbons (compound with double or triple carbon-carbon bonds that enable them to add hydrogen atoms.sp2-hybridizedFor example:C2H4 - ethylene
34This chain contains 6 carbon atoms IUPAC RULESRULE 1. Select the longest continuous carbon chain that contains a double or triple bond.This chain contains 6 carbon atoms
35This chain contains 8 carbon atoms RULE 2. Name this compound as you would an alkane, but change –ane to –ene for an alkene and to –yne for an alkyne.This chain contains 8 carbon atomsName the parent compound octene.This is the longest continuous chain. Select it as the parent compound.
36This chain contains a triple bond. Name the parent compound octyne. RULE 2. Name this compound as you would an alkane, but change –ane to –ene for an alkene and to –yne for an alkyne.This chain contains a triple bond. Name the parent compound octyne.
37RULE 3. Number the carbon chain of the parent compound starting with the end nearer to the double or triple bond. Use the smaller of the two numbers on the double- or triple-bonded carbon to indicate the position of the double or triple bond. Place this number in front of the alkene or alkyne name.
38IUPAC RULESThis end of the chain is closest to the double bond. Begin numbering here.
39IUPAC RULES The name of the parent compound is 1-octene. 4 3 2 1 5 6 7 8
40IUPAC RULES The name of the parent compound is 1-octyne. 8 7 4 3 2 1 6 5
41RULE 4. Branched chains and other groups are treated as in naming alkanes. Name the substituent group, and designate its position on the parent chain with a number.
42IUPAC RULES This is an ethyl group. The ethyl group is attached to carbon 4.4874321654-ethyl-1-octene
43IUPAC RULES 7 4 3 2 1 6 5 8 The ethyl group is attached to carbon 4. 4-ethyl-1-octyne
44must specify whether the molecule is cis or trans (geometric isomer) cis – two particular atoms (or groups of atoms) are adjacent to each othertrans – the two atoms (or groups of atoms) are across from each other
45CYCLOALKENES Contains C=C in the ring Nomenclature of cycloalkenes: Similar to that alkenesCarbons atoms in the double bond are designated C1 and C2
46AROMATIC HYDROCARBONS Contain one or more benzene ringsBenzene Kekulé Structure6 carbons in a ring3 double bonds
47The structure of benzene can be represented in two abbreviated ways. The corner of each hexagon represents a carbon and a hydrogen atom.
49A substituted benzene is derived by replacing one or more of benzene’s hydrogen atoms with an atom or group of atoms.A monosubstituted benzene has the formula C6H5G where G is the group that replaces a hydrogen atom.All hydrogens in benzene are equivalent.It does not matter which hydrogen is replaced by G.
51The name is written as one word. Some monosubstituted benzenes are named by adding the name of the substituent group as a prefix to the word benzene.The name is written as one word.nitro groupethyl groupnitrobenzeneethylbenzene
52phenol toluene Certain monosubstituted benzenes have special names. These are parent names for further substituted compounds.hydroxy groupmethyl groupphenoltoluene
56Three isomers are possible when two substituents replace hydrogen in a benzene molecule. The prefixes ortho-, meta- and para- (o-, m- and p-) are used to name these disubstituted benzenes.
57ortho disubstituted benzene substituents on adjacent carbonsortho-dichlorobenzene (1,2-dichlorobenzene) mp –17.2oC, bp 180.4oC
58meta disubstituted benzene substituents on adjacent carbonsmeta-dichlorobenzene (1,3-dichlorobenzene) mp –24.82oC, bp 172oC
59para disubstituted benzene substituents are on opposite sides of the benzene ringpara-dichlorobenzene (1,4-dichlorobenzene) mp 53.1, bp 174.4oC
60When one substituent corresponds to a monosubstituted benzene with a special name, the monosubstituted compound becomes the parent name for the disubstituted compound.m-nitrophenolphenol
61m-nitrotoluene toluene When one substituent corresponds to a monosubstituted benzene with a special name, the monosubstituted compound becomes the parent name for the disubstituted compound.m-nitrotoluenetoluene
63When a benzene ring has three or more substituents, the carbon atoms in the ring are numbered. Numbering starts at one of the substituent groups.The numbering direction can be clockwise or counterclockwise.Numbering must be in the direction that gives the substituent groups the lowest numbers.
68ALCOHOLSAlcohols: Organic compounds containing hydroxyl (-OH) functional groups.Phenols: Compounds with hydroxyl group bonded directly to an aromatic (benzene) ring.
69CLASSIFICATIONAccording to the type of carbinol carbon atom (C bonded to the –OH group).Classes:i) Primary alcohol- -OH group attached to a primary carbon atomii) Secondary alcohol- -OH group attached to a secondary carbon atomiii) Tertiary alcohol- -OH group attached to a tertiary carbon atom
71Polyhydroxy AlcoholsAlcohols that contain more than one OH group attached to different carbons are called polyhydroxy alcohols.Monohydroxy: one OH group per molecule.Dihydroxy: two OH groups per molecule.Trihydroxy: three OH groups per molecule.
74IUPAC RULESSelect the longest continuous chain of carbon atoms containing the hydroxyl group.Number the carbon atoms in this chain so that the one bonded to the –OH group has the lowest possible number.Form the parent alcohol name by replacing the final –e of the corresponding alkane name by –ol. When isomers are possible, locate the position of the –OH by placing the number (hyphenated) of the carbon atom to which the –OH is bonded immediately before the parent alcohol name.Name each alkyl branch chain (or other group) and designate its position by number.
75This is the longest continuous chain that contains an hydroxy group. Select this chain as the parent compound.
764321This end of the chain is closest to the OH. Begin numbering here.
81EXAMPLE 1) Longest carbon chain = 4 carbons = root name: butanol 2) Position of –OH group = second carbon atom= 2-butanol3) Name of substituents = 1-bromo= 3-methylCOMPLETE IUPAC NAME = 1-bromo-3,3-dimethyl-2-butanol
83Ethers An ether has the formula ROR´. R and R´ can be the same or different groups.R and R´ can be saturated, unsaturated or aromatic.Saturated ethers have little chemical reactivity but are often used as solvents.
84Alcohols and ethers are isomeric. They have the same molecular formula but different structural formulas.An alcohol and its isomeric ether have different chemical and physical properties.
85CH3CH2OHethanol B.P. 78.3oC hydrogen bonds soluble in waterC2H6OCH3–O–CH3dimethyl ether B.P. –27.3oC does not hydrogen bond insoluble in waterC2H6O
87Common Names CH3CH2CH2 — O — CH2CH3 propyl ether ethyl Common names of ethers are formed from the names of the groups attached to the carbon atom in alphabetical order followed by the word ether.CH3CH2CH2 — O — CH2CH3propyletherethylethyl propyl ether
88IUPAC RULES RO– is an alkoxy group. Ethers are named as alkoxy derivatives of the longest carbon-carbon chain in the molecule
89IUPAC RULESSelect the longest carbon-carbon chain and label it with the name of the corresponding alkane.Change the –yl ending of the other hydrocarbon group to –oxy to obtain the alkoxy group name.Combine the names from steps 1 and 2, giving the alkoxy name first, to form the ether name.
90This is the longest carbon-carbon chain. Change the name of the other hydrocarbon group to –oxy.Label it with the name of the corresponding alkane.CH3CH2CH2 — O — CH2CH3ethoxypropaneethylIUPAC name: ethoxypropaneTrivial name: ethyl propyl ether
91ALDEHYDES AND KETONES Functional group: carbonyl group Aldehyde: one hydrogen atom is bonded to the carbon in the carbonyl group.Ketone: the carbon atom in the carbonyl group is bonded to two hydrocarbon groups.
93The IUPAC names of aldehydes are obtained by dropping the –e and adding -al to the name of the parent hydrocarbon.butanealbutanal
94The parent hydrocarbon is the longest chain that carries the –CHO group. This chain has 4 carbon atoms.3214
95The parent hydrocarbon is the longest chain that carries the –CHO group. This chain has 5 carbon atoms.54321
961The –CHO group is always at the beginning of the carbon chain. The carbonyl carbon is numbered as carbon 1.54323-methylpentanal
97The common names of aldehydes are derived from the common names of the carboxylic acids. The –ic acid or –oic acid ending of the acid name is dropped and is replaced with the suffix –aldehyde.butyric acidbutyraldehyde
99The IUPAC name of a ketone is derived from the name of the alkane corresponding to the longest carbon chain that contains the ketone-carbonyl group.The parent name is formed by changing the –e ending of the alkane to -one.propaneonepropanone
100If the carbon chain is longer than 4 carbons, it’s numbered so that the carbonyl carbon has the smallest number possible, and this number is prefixed to the name of the ketone.This end of the chain is closest to the C=O. Begin numbering here.
102ethyl propyl ketone ethyl propyl The common names of ketones are derived by naming the alkyl or aryl groups attached to the carbonyl carbon followed by the word ketone.ethylpropylethyl propyl ketone
103ALKYL HALIDESGeneral formula: CnH2n+1X where n = 1,2,… and X (halogen)Functional group: halogen, -X (X = F, Cl, Br, I)Naming alkyl halides:- same as nomenclature of alkanes
104AMINESAmines are organic compounds and functional groups that contain a basic nitrogen atom with a lone pairFunctional group:Classification of amines:Primary amineSecondary amineTertiary amine
105Primary (1o) amine: one hydrogen of ammonia is replaced by an alkyl or aryl group Secondary (2o) amine: two hydrogens of ammonia is replaced by an alkyl or aryl groupTertiary (3o) amine: three hydrogens of ammonia is replaced by an alkyl or aryl groupQuaternary (4o) amine: an ion in which nitrogen is bonded to four alkyl or aryl groups and bears a positive charge
106NAMING AMINES Common names: - formed from the names of the alkyl groups bonded to nitrogen, followed by the suffix –amine.- the prefixes di-, tri-, and tetra- are used to decribe two, three or four identical substituents.
107NAMING AMINES IUPAC names: - similar to that alcohols. - the longest continuous chain of carbon atoms determine the root name.- the –e in alkane name is changed to –amine, and a number shows the position of the amino group along the chain.- other substituents on the carbon chain are given numbers, and the prefix N- is used for each substituent on nitrogen.
108CARBOXYLIC ACIDS The carboxyl group can also be written as or Functional group: carboxyl group, -COOHThe carboxyl group can also be written asor
1093 2 1 Open-chain carboxylic acids form a homologous series. The carbonyl group ( ) is always at the beginning of a carbon chain.The carbonyl carbon atom is always designated as C-1.321
110methane oic acid methanone The IUPAC name of a carboxylic acid is derived from the name of the alkane corresponding to the longest carbon chain that contains the carboxyl group.The parent name is formed by changing the –e ending of the alkane to –oic acid.methaneoic acidmethanone
112acetic acid common name ethanoic acid formic acid common name Organic acids are usually known by common names.These names usually refer to a natural source of the acid.acetic acidcommon nameethanoic acidformic acidcommon namemethanoic acidIUPAC nameIUPAC name
116OR´ bonded to a carbonyl carbon. An ester is an organic compound derived from a carboxylic acid and an alcohol.carbonyl groupOR´ bonded to a carbonyl carbon.The ester functional group is –COOR.
117Esterification is the reaction of an acid and an alcohol to form an ester. acetic acid (ethanoic acid)ethyl alcohol (ethanol)ethyl acetate (ethyl ethanoate)
118IUPAC NAMEAccording to the IUPAC system the alcohol part of the ester (R΄) is named first.ethyl
119IUPAC NAMEThis is followed by the name of the acid where the –ic ending of the acid has been changed to –ate.ethanoate
120IUPAC NAME ethyl ethanoate According to the IUPAC system the alcohol part of the ester (R΄) is named first.This is followed by the name of the acid where the –ic ending of the acid has been changed to –ate.ethyl ethanoate
121acetic acid → acetate ethyl COMMON NAME The alcohol part is named first (derived from the common names of alcohol).The common names of esters are derived by adding –ate to the name of the acid.acetic acid →acetateethyl
122ethyl acetate COMMON NAME The alcohol part is named first (derived from the common names of alcohol).The common names of esters are derived by adding –ate to the name of the acid.ethyl acetate
124Amide Amide: a composite of a carboxylic acid and ammonia or an amine. Classification of amide:i) primary amide: RCONH2 (two H atoms bonded to N atom)ii) secondary amide: RCONHR’ (one H atomsbonded to N atom)iii) tertiary amide: RCONR’R” (no H atoms bonded to N atom)
125NAMING AMIDE IUPAC name: i) primary amide - first name the corresponding acid. Drop the –ic acid or oic acid, and add the suffix –amide.ammoniaIUPAC nameethanoic acidethanamideCommon nameacetic acidacetamide
126NAMING AMIDE IUPAC name: i) secondary and tertiary amide - treat the alkyl groups on nitrogen as substituents, and specify their position by the prefix N-.
127Acyl halide / acid halides Naming acid halides:- replacing the –ic acid suffix of the acid name with –yl and the halide name.
128Acid anhydride Naming acid anhydride: - the word acid is changed to anhydride in both the common and the IUPAC name
130POLYMERSA polymer is a high molar mass molecular compound made up of many repeating chemical units.Naturally occurring polymersProteinsNucleic acidsCelluloseRubberSynthetic polymersNylonDacronLucite
131The simple repeating unit of a polymer is the monomer. Homopolymer is a polymer made up of only one type of monomer( CF2 CF2 )nTeflon( CH2 CH2 )nPolyethylene( CH2 CH )nClPVC
132Copolymer is a polymer made up of two or more monomers ( CH CH2 CH2 CH CH CH2 )nStyrene-butadiene rubber
133Formation of Polyethylene ethylene monomernCH2=CH2 →CH2 CH2[CH2 CH2]n CH2 CH2 CH2 CH3n = the number of monomer units.n ranges from 2,500 to 25,000
134SOME MONOMERS AND THEIR COMMON SYNTHETIC POLYMERS
135USES AND IMPORTANCE OF ORGANIC COMPOUNDS NYLONNylons are condensation copolymers formed by reacting equal parts of a diamine and a dicarboxylic acids, so that peptide bonds form at both ends of each monomer in a process analogous to polypeptides biopolymers.General reactions:NylonDicarboxylic acidsDiamines
136Basic concepts of nylon production The first approach:combining molecules with an acid (COOH) group on each end are reacted with two chemicals that contain amine (NH2) groups on each end.Form nylon 6,6, made of hexamethylene diamine with six carbon atoms and acidipic acid, as well as six carbon atoms.The second approach:a compound has an acid at one end and an amine at the other and is polymerized to form a chain with repeating units of (-NH-[CH2]n-CO-)x.Form nylon 6, made from a single six-carbon substance called caprolactam.
137Uses and important of nylon Apparel: Blouses, dresses, foundation garments, hosiery, lingerie, raincoats, ski apparel, windbreakers, swimwear, and cycle wearHome Furnishings: Bedspreads, carpets, curtains, upholsteryIndustrial and Other Uses: Tire cord, hoses, conveyer and seat belts, parachutes, racket strings, ropes and nets, sleeping bags, tarpaulins, tents, thread, monofilament fishing line, dental floss
138AZO-DYES Azo compounds: - compounds bearing the functional group R-N=N-R',in which R and R' can be either aryl or alkyl.- N=N group is called an azo group- HNNH is called diimideAryl azo compounds have vivid colors, especiallyreds, oranges, and yellowsYellow azo dye
139Uses and important of azo dye Methyl orange - used as acid-base indicators due to the different colors of their acid and salt formsArtist’s paints – clays, yellow to red rangeDye in food and textiles
140EXAMPLES OF AZO DYES USED IN FOOD E102: TartrazineE107 : Yellow 2GE110 : Sunset YellowE122 : AzorubineEXAMPLES OF AZO DYES USED IN FOOD
141E123 : AmaranthE124 : Ponceau 4RE129 : Allura RedE151 : Brilliant Black
142FUELAny material that is burned or altered to obtain energy and to heat or to move an objectIts energy can be stored to be released only when needed, and that the release is controlled in such a way that the energy can be harnessed to produce workExamples: Methane, petrol and oil.Application of energy released from fuels:- cooking- powering weapons to combustion- generation of electricityFuel oil: generate heat or used in an engine for the generation of power