Organic Chemistry

Organic Chemistry The chemistry of life!

Organic Chemistry • The study of carbon and most carbon compounds. • Originally thought to only be made by living things, to get the name organic. • It is now known that organic chemistry has more compounds than that made by living things.

Why so many compounds? • Carbon can bond with carbon atoms to form rings, chains and networks • They then form with groups of other atoms to form many compounds

Bonding of Carbon Atoms • Carbon atoms covalently bond with other carbon atoms to form chains • Can be as little as 2 and as many as thousands ** Remember that covalent bonds • form molecules that are poor conductors • have low melting and boiling points • tend to be nonpolar.

CARBON ATOMS • Has 6 protons, 6 electrons • Electron dot diagram has 4 valence electrons • Can covalently bond with nonmetals • Can covalently bond with itself and can form single, double or triple bonds • The bonded substances are usually nonpolar

Shapes of Carbon Bonding • Forms single bonds with other elements at 109.5º • Long chains • Rings

Carbon Bonds • Single Bonds where only one pair of electrons are shared is saturated • Double and triple bonds where 2 and 3 pairs of electrons are shared are unsaturated • Can be open (chains), closed (rings) or networked (lattice) ex: Diamonds

Hydrocarbons • Hydrocarbons – organic compounds that contain only hydrogen and carbon • Homologous series – a group of related compounds in which each member differs from the one before by the number of carbons • Alkanes, Alkynes and Alkenes are 3 important homologous series of hydrocarbons ***listed in Table Q

Alkanes A homologous series of saturated hydrocarbons that release energy when burned • Made only of hydrogen and carbon • Homologous series – each Alkane differs from another by the number of carbons • Saturated means all carbons in Alkanes have single bonds

Examples of Alkanes • General Formula CnH2n+2 • Methane – 90% of natural gas CH4 • Ethane – 10% of natural gas C2H6 • Propane – used for outdoor grills C3H8 • Butane – used as lighter fluid C4H10 As the number of carbons increase the boiling point increases and bond strength increases ** Table P lists all organic prefixes

Alkenes A homologous series of unsaturated hydrocarbons that are used to make other items like plastics • Made only of hydrogen and carbon • Homologous series – each Alkene differs from another by the number of carbons • Unsaturated means all carbons in Alkenes have double bonds

Examples of Alkenes • General Formula CnH2n • Ethene – C2H4 • Propene – C3H6 • Butene – C4H8 ** Table P lists all organic prefixes

Alkynes A homologous series of unsaturated hydrocarbons that are used to make other items like fuels • Made only of hydrogen and carbon • Homologous series – each Alkyne differs from another by the number of carbons • Unsaturated means all carbons in Alkynes have triple bonds

Examples of Alkynes • General Formula CnH2n-2 • Ethyne – C2H2 • Propyne – C3H4 • Butyne – C4H6 ** Table P lists all organic prefixes

Isomers When hydrocarbons are formed there are more than one way to arrange the atoms

Facts on Isomers Isomers: • Have the same molecular formula • Different chemical and physical properties • As number of carbons increases so does the number of isomers for that molecule

Naming Hydrocarbon Compounds Naming the Normal Form (straight line) • Must have continuous straight chain of carbons • Count number of carbons • Choose prefix from table P • Check for # of bonds between carbons • Use n and then the name Ex: n- butane IUPAC (international union of pure and applied chemistry)

Naming Branched Chains of Hydrocarbons • Name the longest continuous hydrocarbon chain first • Check for each branch attached. • Branch names use the same prefix • Uses –yl ending • Has one less hydrogen • Carbons are numbered to give the lowest number in the name for the location • More than 1 of the same group use di-, tri- and tetra- prefixes before the branch name

Functional Groups Atoms or groups of atoms that replace one or more hydrogen atoms in a hydrocarbon. ***Listed on Table R Halides Amides Alcohols Amino Acids Aldehydes Amines Ketones Esters Ethers Organic Acids

Halides • A.k.a organic halides or halocarbon) • When group 17 atoms replace a hydrogen • Used as solvents and pesticides • Named by citing the location where it is attached to the hydrocarbon

Aldehydes • When an O atom is attached to a carbon chain by a double covalent bond • Called a carbonyl group • Carbonyl group formula is – C = O • The carbonyl group is on the end of a hydrocarbon • Named by substituting the e ending with -al • Often used as preservatives

Ketones • When the carbonyl group is found on an inside carbon • Named by replacing the e ending with –one • Often used as solvents

Ethers • A series of organic compounds where two carbon chains are joined together by an oxygen atom • Named by using alkyl groups and ending with ether

Organic Acids • Homologous series of organic compounds with a carboxyl group • Carboxyl group formula is – COOH • Named by replacing the e ending with –oic acid • Creates a weak electrolyte

Esters • Compounds whose formula is CO – O • Is part of an organic acid • Has strong fragrant aromas and is responsible for many smells in fruits

Amines • Derivative of ammonia • Formed when 1 or more hydrogen atoms of ammonia is replaced with an alkyl group • The Alkane chain is numbered to show the location • Named by replacing the e ending with –amine • Important for B vitamins, hormones and anesthetics

Amino Acids • Contains carboxyl groups and amine groups • The amine group is attached to the carbon atom that is adjacent to the acid group • The rest of the molecule is a hydrocarbon chain • Necessary for the building blocks of protein

Amides • A compound formed by the combination of two amino acids • When on of the hydrogen atoms of an amino group reacts with an –OH of an organic acid condensation occurs • Water and an amide is formed • Known as a peptide link • Eventually a polypeptide will form a protein

Alcohols When one or more of the hydrogen atoms are replaced by an –OH group • The -OH group is called a hydroxyl • Does not form electrolytes • Does not form hydroxide ions in water • Does not react with indicators • Forms polar molecules

Classification of Alcohols • Classified as primary, secondary or tertiary depending on where the hydroxyl group is located • Primary, attached to the carbon at the end of the chain • Secondary, attached to a carbon in the middle of a chain • Tertiary, attached to a carbon with a branching alkyl group

Dihydroxy and Trihydroxy Alcohols • Can also be classified by the number of hydroxyl groups • Dihydroxy alcohols have 2 groups attached to a carbon chain • Trihydroxy alcohols have 3 hydroxyl groups attached to a carbon chain

Types of Organic Reactions • Combustion • Substitution • Addition • Esterification • Saponification • Fermentation • Polymerization

Combustion • Almost all organic compounds will burn • Requires oxygen • Produces carbon dioxide and water C3H8(g) + 5O2(g) 3CO2(g) + 4H2O

Substitution • Similar to a replacement reaction • Substitutes one or more atoms or functional groups C2H6 + Cl2 C2H5Cl + HCl

Addition • Similar to a synthesis reaction • Adds one or more atoms or functional groups C2H4 + Cl2 C2H4Cl2

Esterification • A reaction between an organic acid and an alcohol • Produces an ester and water CH3OOH + CH3CH2OH H2O + CH3COOCH2CH3

Saponification • A reaction between an inorganic base and an ester • Produces an alcohol and a soap Fat + Base Glycerol + Soap

Fermentation • A reaction where yeast cells break down sugar • Produces carbon dioxide and Alcohol C6H12O6 2C2H5OH + 2CO2

Polymerization • Organic compound made up of log carbon chains bonded together • Each unit of polymer is called a monomer • Produces products like rayon, nylon, and polyethylene • Organic polymers include proteins, starches and cellulose

Addition & Condensation Polymerization • Addition is the joining of monomers of unsaturated compounds • Condensation is the removing of water from hydroxyl groups and joining by ether or ester linkage

Organic Chemistry