1. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 1 Introductory Chemistry: A Foundation FIFTH EDITION by Steven S. Zumdahl University of Illinois

2. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 2 Organic Chemistry Chapter 19

3. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 3 Structure Determines Properties Organic compounds all contain carbon –CO, CO 2, carbonates and carbides are inorganic –Other common elements are H, O, N, (P, S) Carbon has versatile bonding patterns –Chains, rings, multiple bonds –Chain length nearly limitless Carbon compounds generally covalent –Molecular; Gases, liquids or low melting solids; Varying solubilities; Nonconductive in liquid C - C bonds unreactive (very stable)

4. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 4 Carbon Bonding Carbon can bond to other carbon atoms in an almost infinite chain Bond to a maximum of four other atoms –Carbon or other elements –Carbon with 4 single covalent bonds = tetrahedral –Carbon with 2 single & 1 double covalent bond = trigonal planar –Carbon with 1 single & 1 triple covalent bond = linear

5. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 5 Hydrocarbons Hydrocarbons contain only C & H – Aliphatic or aromatic Aliphatic hydrocarbons – Saturated or unsaturated aliphatics Saturated = alkanes, unsaturated = alkenes or alkynes Unsaturated have double or triple bonds – May be chains or rings Ring molecules have two less H than chain so that ends can join – Chains may be straight or branched

6. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 6 Alkanes a.k.a paraffins Aliphatic General formula C n H 2n+2 for chains Very unreactive Come in chains or/and rings –CH 3 groups at ends of chains, CH 2 groups in the middle Saturated Branched or Straight-Chain –Straight-chain = normal –Condensed formula has CH 3 on each end and CH 2 in middle

7. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 7 Condensed Structural Formulas attached atoms listed in order – central atom with attached atoms follow normal bonding patterns – use to determine position of multiple bonds () used to indicate more than 1 identical group attached to same previous central atom – unless () group listed first in which case attached to next central atom

8. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 8 Structural Isomers Isomers are molecules with the same molecular formula but different arrangements of the atoms –Different chemical and physical properties Structural isomers are isomers in which the atoms are attached differently –Different bonding pattern –Different properties –a.k.a constitutional isomers

9. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 9 Naming each name consist of 3 parts ¶ prefix indicates position, number and type of branches indicates position, number and type of each functional group · parent indicates the length of the longest carbon chain or ring ¸ suffix indicates the type of hydrocarbon –ane, ene, yne certain functional groups

10. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 10 Naming Alkanes The first 4 alkanes are methane (C 1 ), ethane (C 2 ), propane (C 3 ), butane (C 4 ) After that the names come from adding Greek prefix to –ane dec10 non9 oct8 hept7 hex6 pent5 PrefixNumber of Carbons

11. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 11 Naming Alkanes ÊFind the longest, continuous carbon chain ËNumber the chain from end closest to a branch –if first branches equal distance use next in ÌName branches as alkyl groups –Branch name related to number of C –End in -yl –locate each branch by preceding its name with the carbon number on the chain ÍList branches alphabetically –do not count n-, sec-, t-, count iso ÎUse prefix if more than one of same group present –di, tri, tetra, penta, hexa –do not count in alphabetizing

12. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 12 Petroleum Formed when ocean microorganisms died 500 million year ago, were buried, and subjected to large pressures A dark, thick liquid composed mainly of hydrocarbons Natural gas normally found with petroleum deposits –Mostly methane with some ethane, propane and butane Petroleum separated into various fractions by distillation –Separation based on boiling point

13. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 13 Alkane Reactions Combustion Substitution Dehydrogenation 2 CH 3 CH 2 CH 2 CH 3 + 13 O 2  8 CO 2 + 10 H 2 O CH 3 CH 2 CH 2 CH 3  CH 3 CH = CHCH 3 + H 2  cat. CH 3 CH 2 CH 2 CH 3 + Cl 2  CH 3 CH 2 CHClCH 3 + HCl h

14. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 14 Alkenes Also known as olefins Aliphatic, unsaturated Formula of chain alkenes - subtract 2 H from alkane formula for each double bond C=C double bonds Trigonal shape around C –Flat No rotation –Cis - trans isomerism Much more reactive than alkanes Polyunsaturated = many double bonds

15. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 15 Reactions of Alkenes Combustion Addition Reactions Hydrogenation Hydrohalogenation Hydration

16. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 16 Naming Alkenes change suffix on main name from -ane to -ene number from end closest to double bond number in front of main name indicates first carbon of double bond Naming Alkynes change suffix on main name from -ane to -yne number from end closest to triple bond number in front of main name indicates first carbon of triple bond

17. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 17 Alkynes Also known as acetylenes Aliphatic, unsaturated Formula of chain alkynes - subtract 4 H from alkane for each triple bond C  C triple bond Linear shape No rotation More reactive than alkenes

18. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 18 Aromatics Contain 1 or more 6 C unsaturated rings –Benzene rings Chemical reactions different than alkenes –Burn sooty instead of clean –Undergo substitution instead of addition Benzene –Liquid, BP = 80°C –All C-C bond lengths and bond angles identical 120° Bond lengths between C-C and C=C –Planar molecule –Resonance hybrid

19. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 19 Naming Benzene Derivatives main name either benzene or one of the common derivatives ring numbered from position of main group or 2 = ortho (o), 3 = meta (m), 4 = para (p)

20. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 20 Functional Groups In many organic compounds, C-to-H bonds are replaced by bonds to other atoms –C-Halogen, C-to-O, C-to-N, occasionally (C-to-S) These compounds are generally considered hydrocarbon derivatives –Basically hydrocarbons with a few substitutions These substituted bonds are more reactive than C-H bonds Therefore, when molecules with the substituted bonds react, the reaction site is generally at the substituted bonds These substituted atoms or groups of atoms are called functional groups, and they generally determine the chemical reactions an organic molecule will undergo –And also have influences on intermolecular attractions and therefore physical properties

21. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 21 Alcohols Have an –OH group in place of a H Form H-bonds –To alcohol molecules and water Solubility in water decreases as length of carbon chain increases Common reactions include substitution for OH, elimination, oxidation Naming Alcohols Select the longest chain of carbon atoms containing the –OH group Number the chain from the end closest to the –OH group Determine the parent name from the number of C in the chain, replace the final -e with -ol Name alkyl branches as usual

22. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 22 Classifying Carbons Carbons in an organic molecule are classified based on the number of other carbons they are attached to Primary Carbon, 1°, = carbon attached to one other carbon Secondary Carbon, 2°, = carbon attached to 2 other carbons Tertiary Carbon, 3°, = carbon attached to 3 other carbons Quaternary Carbon, 4°, = carbon attached to 4 other carbons –Very unreactive Hydrogens are classified based on carbon they are attached to –The hydrogens on a 1° carbon are called 1° hydrogens

23. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 23 Classifying Alcohols alcohols are classified based on the carbon they are attached to Primary Alcohol, 1°, = OH group on 1° C Secondary Alcohol, 2°, = OH group on 2° C Tertiary Alcohol, 3°, = OH group on 3° C

24. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 24 Aldehydes and Ketones Both contain C=O, carbonyl group In ketones, the carbonyl group is attached to 2 carbon atoms –In middle of a chain or ring In aldehydes, the carbonyl group is attached to a carbon and a hydrogen –Or 2 H in the case of formaldehyde –Must be on the end of a chain

25. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 25 Ketones Often used as polar solvent when presence of OH cause problems Acetone – R1 = R2 = CH 3 –Nail polish remover, paint solvent MEK = methyl ethyl ketone – R1= CH 3, R2 = CH 2 CH 3 –Paint solvent, gasoline additive Aldehydes Often strong odors, Used as fragrances and food additives Formaldehyde – R1 = R2 = H Gas, when dissolved in water = formalin Suspected carcinogen Used in the production of foams and adhesives Acetaldehyde – R1 = H, R2= CH 3

26. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 26 Naming Aldehydes Select the longest chain of carbon atoms containing the aldehyde group Number the chain calling the carbonyl C position 1 Determine the parent name from the number of C in the chain, replace the final -e with -al Name alkyl branches as usual Naming Ketones Select the longest chain of carbon atoms containing the carbonyl group Number the chain from the end closest to the carbonyl group Determine the parent name from the number of C in the chain, replace the final -e with -one Name alkyl branches as usual

27. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 27 Carboxylic Acids Have carboxyl group, R1-COOH Always on end of chain Acid functional group –Weak acid Made by oxidation of 1° alcohols –under stronger conditions Formic Acid, R1 = H –Bee and ant stings Acetic Acid, R1 = CH 3 –vinegar

28. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 28 Esters Replace acid H of carboxy group with R group, R1-COOR2 Sweet, fruity odors Made by reacting carboxylic acid with an alcohol R1-COOH + R2-OH  R1-COOR2 + H 2 O –Not like neutralization, alcohol not a base!

29. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 29 Naming Carboxylic Acids Select the longest chain of carbon atoms containing the carboxy group Number the chain calling the carboxy C position 1 Determine the parent name from the number of C in the chain, replace the final -e with –oic acid Name alkyl branches as usual Naming Esters Select the longest chain of carbon atoms containing the ester group Name R2 as alkyl group Name R1 and carboxy C like acid except change the –ic ending to -ate Put the pieces together, alkyl group first

30. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 30 Polymers Generally organic molecules Very large, molar masses 10,000+ Chain-like molecules made by linking together small molecules called monomers –Monomer units usually indicated in name with the prefix “poly-” –polyethylene, polypropylene, polystyrene

31. Copyright©2004 by Houghton Mifflin Company. All rights reserved. 31 Linking Monomers Addition Polymerization = monomers linked by each molecule attaching to chain by a synthesis type reaction Condensation Polymerization = monomers linked when a reaction occurs that splits out a small molecule, like water Homopolymers all monomer units alike Copolymers have multiple monomer units