ORGANIC CHEMISTRY Organic Chemistry • Study of carbon and carbon compounds • Organic compounds contain carbon atoms which covalently bond to each other in chains, rings, and networks to form a variety of structures General Characteristics of Organic Compounds • Nonpolar • Soluble in nonpolar solvents / insoluble in polar solvents (water) “Like dissolves Like” • Poor conductors of heat and electricity – Exception: aqueous organic acids conduct • Low melting and boiling points • React slower than inorganic compounds – High activation energies • Molecular Formulas – Indicates the kind and number of atoms of each element in the compound – Example: C2H6 • Empirical Formulas – Reduced formula, in lowest terms – Example: What is the empirical formula for C4H10 • Structural Formulas – Attempts to show the bonding patterns and approximate shapes – Ex: • Condensed Structural Formulas – Shows the connections without showing the shape and bonds – Ex: Bonding • Carbon- has 4 valence electrons, needs 4 more, forms 4 bonds • Oxygen – has 6 valence electrons, needs 2 more, forms 2 bonds • Hydrogen – has 1 valence electron, needs 1 more, forms 1 bond • Halogens (group 17) – has 7 valence electrons, needs 1 more, forms 1 bond Homologous Series (Families) • Group of related compound in which each member has one more group – Ex: CH3CH2CH3 and CH3CH2CH2CH3 • Members of a group will have similar structures and properties • As the members of a series increase in mass, their boiling (and melting) points increase – due to increased intermolecular forces Hydrocarbons • Organic compounds that contain only CARBON and HYDROGEN ALKANES... SINGLE bonds between Carbons Saturated hydrocarbon CxH2x+2 Family Name ALKENES... ONE DOUBLE bond between two Carbons ALKYNES... ONE TRIPLE bond between two Carbons Unsaturated hydrocarbon Unsaturated Hydrocarbon CxH2x CxH2x-2 PREFIXES …counting the CARBONS ALKANES • Contain all single bonds • Naming: carbon prefix + -ane Example: Ethane Butane Octane C4H10 ALKENES • Contain 1 double bond • Naming: carbon prefix + -ene – A number is used in front to indicate the location of the double bond – If a number is not indicated the double bond comes after the 1st carbon Example: 2-Pentene Diene • Contains 2 double bonds • Naming: location-carbon prefix-diene Propadiene • Example: 1,3-pentadiene C3H4 ALKYNES • Contains 1 triple bond • Naming: carbon prefix + -yne Example: Ethyne Ethyne Propyne • Saturated Compounds – contains all single carbon-carbon bonds • Unsaturated Compounds – contains at least multiple carbon-carbon bond Branched Hydrocarbons • Contain 1 or more branches off the main chain Methyl group on carbon 4 8 7 6 5 4 3 2 4-methyl-ocatane 1 Naming Branched Hydrocarbons • Find the longest continuous chain, name it • To name the branches: number of carbons + “-yl” – Examples: • CH3 = methyl • CH2CH3 = ethyl • The location of the alkyl (branched group) is indicated – If there is more than one of the same branch, use prefixes (di, tri, tetra, …) – The carbon chain must be numbered from the end that will give the lowest numbers for the branches Example: 2, 2, 3 – trimethyl pentane SAME…BUT DIFFERENT • Same – number and type of atoms • Different – structure and name ď‚·Have different physical and chemical properties 2 CARBONS 6 HYDROGENS 1 OXYGEN ETHANOL DIMETHYL ETHER a primary alcohol C2H5 OH CH3OCH3 GROUPS and COMPOUNDS • Functional Group: halogen (group 17 element) • Name: location-halide-carbon chain • Examples: 1. 2-bromobutane 2. 1,3 - dichloropentane ALCOHOLS • • • • • Functional Group: -OH No more than one –OH group can be attached to any one carbon The carbon to which the –OH group is attached must have all single bonds Alcohols are not bases (do not ionize in water) Name: hydrocarbon name, replace the final –e with –ol Examples: 1. Methanol 2. 2-Propanol Types of Alcohols • Monohydroxy – contain 1 –OH group – Primary – Secondary – Tertiary • Dihydroxy (Diol) – contain 2 –OH groups • Trihydroxy (Triol) – contain 3 –OH groups Primary Alcohols • • • Contain 1 –OH group -OH group is attached to the end of the chain Examples: 1. Ethanol 2. Propanol H SECONDARY ALCOHOL •Contain 1 –OH group R-C-R O H •Carbon that is attached to the –OH group is attached to 2 other carbon atoms 2-Butanol 4 CARBONS -OH GROUP ON SECOND CARBON FROM RIGHT R TERTIARY ALCOHOL R-C-R O •Contain 1 –OH group H •Carbon attached to the –OH group is attached to three other carbon atoms Methyl group 2METHYL,2-BUTANOL Ethyl group Methyl group -OH GROUP ON SECOND CARBON FROM RIGHT 4 CARBONS in sequence 2 -OH groups are present 1,2 ethanediol 3 -OH groups are present 1,2,3 propanetriol •Functional Group = -COOH •Name: Hydrocarbon name, drop the final “e” and replace it with “–oic” followed by the word “acid” •Examples: 1. Ethanoic Acid 2. Butanoic Acid CH3COOH • Functional Group: -CHO • Name: drop the final “e” and add “-al” ethanal 2 carbons alkane aldehyde Propanal CH3CHO • Functional Group: -CO• Name: Hydrocarbon name, drop the final “e”, add “one” Propanone CH3COCH3 2-Butanone • Functional group: -O- (chain-O-chain) • Name: 1. Name each hydrocarbon chain – drop the ending add “yl” 2. Add “ether” to the end diethyl ether Ethyl methyl ether C2H5OC2H5 • Functional Group: -COOR • Formed from a dehydration reaction of an alcohol and an acid • Fruity odor • Name: • Name each hydrocarbon chain – The part with the –CO gets the “-oate” ending – The other part gets the “-yl” ending Ester Examples • Ethyl Methanoate HCOOC2H5 • Ethyl Ethanoate • Functional Group: NH2 • Name the chain, add “amine” to the end ethanamine C2H5NH2 • Functional Group: R-CONH2 • Name: Name the chain, add “amide” to the end Butanamide Propanamide C3H7CONH2 • Functional Groups: -NH2 and –COOH • Just like an alcohol, but –SH instead of – OH Example: Methyl Thiol (CH3SH) ADDITION SUBSTITUTION ESTERIFICATION SAPONIFICATION POLYMERIZATION COMBUSTION FERMENTATION • Something takes the place of something else • Starts with a saturated hydrocarbon C2H 6 Cl2 C2H4 Cl2 H2 • Start with an unsaturated hydrocarbon • Break the double (or triple) bond • Add in an atom (or group) C 2H 4 Cl2 C2H4 Cl2 Concentrated H2SO4 acts as a dehydrating agent ORGANIC ACID + ALCOHOL C2H5 COOH H2SO4 CH3 OH ESTER + WATER C2H5 COOCH3 H 2O • Reverse of esterification, carried out in the presence of a base • See p.169 for an example FAT (glycerol ester) Strong base (NaOH or KOH) SOAP glycerol (trihydroxy alcohol) 1,2,3 propane triol C6H12 O6 GLUCOSE ZYMASE C2H5 OH ETHANOL CO2 CARBON DIOXIDE • Hydrocarbon + O2 • Exothermic Example: C2H6 + O2 CO2 + H2O Poly...poly...poly…poly...poly...polymerization • Chains of small units make up a MACROMOLECULE • Examples: Plastics, proteins Condensation Polymerization • Bonding of monomers by a dehydration reaction – OH groups of adjacent alcohols react, water is removed, the 2 molecules are connected by the remaining O • Examples: Nylon, Protein, Polyester Addition Polymerization • Bonding of monomers of unsaturated compounds by “opening” a multiple bond in the carbon chain • Example: polyethylene and many plastics n C 2H 4 (C2H4)n