1. Alkyne combustion reaction: 2 C 2 H 2 + 5 O 2 4 CO 2 + 2 H 2 O The combustion reactions are all exothermic. 180

2. Substitution Reactions 181

3. Substitution Reactions Reaction with chlorine: 182

4. Substitution Reactions Reaction with chlorine: CH 4 + Cl 2 CH 3 Cl + HCl chloromethane 183

5. Substitution Reactions Reaction with chlorine: CH 4 + Cl 2 CH 3 Cl + HCl chloromethane CH 3 Cl + Cl 2 CH 2 Cl 2 + HCl dichloromethane 184

6. CH 2 Cl 2 + Cl 2 CHCl 3 + HCl trichloromethane 185

7. CH 2 Cl 2 + Cl 2 CHCl 3 + HCl trichloromethane CHCl 3 + Cl 2 CCl 4 + HCl tetrachloromethane 186

8. For organic reactions it is common practice to indicate the reaction conditions. That is, for the reaction with chlorine: 187

9. For organic reactions it is common practice to indicate the reaction conditions. That is, for the reaction with chlorine: CH 4 + Cl 2 CH 3 Cl + HCl 188

10. For organic reactions it is common practice to indicate the reaction conditions. That is, for the reaction with chlorine: heat (300 o C) CH 4 + Cl 2 CH 3 Cl + HCl 189

11. For organic reactions it is common practice to indicate the reaction conditions. That is, for the reaction with chlorine: heat (300 o C) CH 4 + Cl 2 CH 3 Cl + HCl or uv irrad. room temp. 190

12. Addition Reactions 191

13. dark Cl 2 + 25 o C 1,2- dichloroethane 192

14. CH 3 CCH + 2 Cl 2 CH 3 CCl 2 CHCl 2 propyne 1,1,2,2-tetrachloropropane CH 3 CHCH 2 + HBr CH 3 CHBrCH 3 propene 2-bromopropane It turns out that when a hydrogen halide add to an alkene, the more electronegative halogen atom always tends to end up on the carbon atom of the double bond that has fewer hydrogen atoms (Markovnikov’s rule). 193

15. H 2 SO 4 CH 2 CH 2 + H 2 O CH 3 CH 2 OH 194

16. Hydrogenation The following reaction is an example of hydrogenation of an alkene, addition of H 2 across a double bond. 195

17. + H 2 ethene ethane 196

18. Functional Group Concept 197

19. Functional Group Concept A great many organic molecules have complex structures. 198

20. Functional Group Concept A great many organic molecules have complex structures. Trying to predict the properties and possible reactions of a complex structure can be very difficult. 199

21. Functional Group Concept A great many organic molecules have complex structures. Trying to predict the properties and possible reactions of a complex structure can be very difficult. Chemists have found it very useful to characterize certain well defined fragments of an organic molecule. 200

22. Functional Group Concept A great many organic molecules have complex structures. Trying to predict the properties and possible reactions of a complex structure can be very difficult. Chemists have found it very useful to characterize certain well defined fragments of an organic molecule. These fragments (in isolation) have well defined reactive capabilities. 201

23. When these units are found in complex structures, predictions can be made as to the likely properties and reactions of the complex structure. 202

24. When these units are found in complex structures, predictions can be made as to the likely properties and reactions of the complex structure. These fragment units are called functional groups. 203

25. Some common functional groups Functional Name Example IUPAC Name Common Name group formula 204

26. Some common functional groups Functional Name Example IUPAC Name Common Name group formula R O H alcohol CH 3 OH methanol methyl alcohol 205

27. Some common functional groups Functional Name Example IUPAC Name Common Name group formula R O H alcohol CH 3 OH methanol methyl alcohol R C carboxylic CH 3 CO 2 H ethanoic acid acetic acid acid 206

28. Some common functional groups Functional Name Example IUPAC Name Common Name group formula R O H alcohol CH 3 OH methanol methyl alcohol R C carboxylic CH 3 CO 2 H ethanoic acid acetic acid acid R C ketone CH 3 COCH 3 propanone acetone 207

29. Some common functional groups Functional Name Example IUPAC Name Common Name group formula R O H alcohol CH 3 OH methanol methyl alcohol R C carboxylic CH 3 CO 2 H ethanoic acid acetic acid acid R C ketone CH 3 COCH 3 propanone acetone R and are alkyl (or more complicated groups). cannot be H. R cannot be H for the alcohol (that would be water!), nor for the ketone (that would give an aldehyde). 208

30. Functional Name Example IUPAC Name Common Name group formula R C aldehyde HCHO methanal formaldehyde 209

31. Functional Name Example IUPAC Name Common Name group formula R C aldehyde HCHO methanal formaldehyde R C ester CH 3 CO 2 CH 2 CH 3 ethyl ethanoate ethyl acetate 210

32. Functional Name Example IUPAC Name Common Name group formula R C aldehyde HCHO methanal formaldehyde R C ester CH 3 CO 2 CH 2 CH 3 ethyl ethanoate ethyl acetate R NH 2 amine CH 3 NH 2 aminomethane methylamine 211

33. Functional Name Example IUPAC Name Common Name group formula R C aldehyde HCHO methanal formaldehyde R C ester CH 3 CO 2 CH 2 CH 3 ethyl ethanoate ethyl acetate R NH 2 amine CH 3 NH 2 aminomethane methylamine R and are alkyl (or more complicated groups). cannot be H (that would give an acid). R cannot be H for the amine (that would be ammonia!). 212

34. Functional Name Example IUPAC Name Common Name group formula R O ether CH 3 OCH 3 methoxymethane dimethyl ether 213

35. Functional Name Example IUPAC Name Common Name group formula R O ether CH 3 OCH 3 methoxymethane dimethyl ether R C amide CH 3 CONH 2 ethanamide 214

36. Functional Name Example IUPAC Name Common Name group formula R O ether CH 3 OCH 3 methoxymethane dimethyl ether R C amide CH 3 CONH 2 ethanamide R and are alkyl (or more complicated groups). cannot be H (that would give an alcohol). R cannot be H for the ether (that would also give an alcohol). 215

37. Summary of name endings 216

38. Summary of name endings Functional group Parent alkane name ending 217

39. Summary of name endings Functional group Parent alkane name ending alcohol change e to ol 218

40. Summary of name endings Functional group Parent alkane name ending alcohol change e to ol carboxylic acid change e to oic acid 219

41. Summary of name endings Functional group Parent alkane name ending alcohol change e to ol carboxylic acid change e to oic acid ketone change e to one 220

42. Summary of name endings Functional group Parent alkane name ending alcohol change e to ol carboxylic acid change e to oic acid ketone change e to one aldehyde change e to al 221

43. Summary of name endings Functional group Parent alkane name ending alcohol change e to ol carboxylic acid change e to oic acid ketone change e to one aldehyde change e to al amide change e to amide 222

44. Summary of name endings Functional group Parent alkane name ending alcohol change e to ol carboxylic acid change e to oic acid ketone change e to one aldehyde change e to al amide change e to amide amine insert amino in front of alkane name 223

45. Summary of name endings Functional group Parent alkane name ending alcohol change e to ol carboxylic acid change e to oic acid ketone change e to one aldehyde change e to al amide change e to amide amine insert amino in front of alkane name ester insert alkyl name then change e to oate 224

46. Summary of name endings Functional group Parent alkane name ending alcohol change e to ol carboxylic acid change e to oic acid ketone change e to one aldehyde change e to al amide change e to amide amine insert amino in front of alkane name ester insert alkyl name then change e to oate ether change ane to oxy then add in second alkane name. 225

47. Key comment on a functional group The carboxylic acid is a combination of two functions groups: O O C C plus O H O H carboxylic acid ketone alcohol 226

48. Key comment on a functional group The carboxylic acid is a combination of two functions groups: O O C C plus O H O H carboxylic acid ketone alcohol HOWEVER, a compound such as 227

49. CH 3 CH 2 CCH 2 CH 2 OH O would NOT function like a carboxylic acid, but as an alcohol in some reactions and a ketone in some other reactions. 228

50. Comparison of some properties 229

51. 230

52. 231

53. 232

54. Some simple representative reactions of a few functional groups. 233

55. Formation of an ester: O O CH 3 C + CH 3 CH 2 OH CH 3 C + H 2 O O H OCH 2 CH 3 carboxylic acid alcohol ester 234

56. Formation of an ester: O O CH 3 C + CH 3 CH 2 OH CH 3 C + H 2 O O H OCH 2 CH 3 carboxylic acid alcohol ester ethanoic acid ethanol ethyl ethanoate 235

57. Oxidation of an alcohol: H 2 SO 4,K 2 Cr 2 O 7 CH 3 CH 2 OH alcohol warm 236

58. Oxidation of an alcohol: H 2 SO 4,K 2 Cr 2 O 7 O CH 3 CH 2 OH CH 3 C alcohol warm H aldehyde 237

59. Oxidation of an alcohol: H 2 SO 4,K 2 Cr 2 O 7 O CH 3 CH 2 OH CH 3 C alcohol warm H aldehyde further warming O carboxylic acid CH 3 C O H 238

60. Note: In organic reactions, the side products (e.g. Cr 3+ in the preceding reaction) are often not given. Here is the complete chemical equation: 239

61. Note: In organic reactions, the side products (e.g. Cr 3+ in the preceding reaction) are often not given. Here is the complete chemical equation: 16 H + + 2 Cr 2 O 7 2- + 3 CH 3 CH 2 OH 4 Cr 3+ +3CH 3 CO 2 H + 11 H 2 O 240

62. Note: In organic reactions, the side products (e.g. Cr 3+ in the preceding reaction) are often not given. Here is the complete chemical equation: 16 H + + 2 Cr 2 O 7 2- + 3 CH 3 CH 2 OH 4 Cr 3+ +3CH 3 CO 2 H + 11 H 2 O (orange) (green) 241

63. The intermediate reaction would be: 8 H + + Cr 2 O 7 2- + 3 CH 3 CH 2 OH 2 Cr 3+ + 3 CH 3 CHO + 7 H 2 O (orange) (green) 242

64. Oxidation of an alcohol: OH H 2 SO 4,K 2 Cr 2 O 7 O CH 3 CHCH 3 CH 3 CCH 3 alcohol or KMnO 4 ketone 243

65. Aromatic Compounds 244

66. Aromatic Compounds Aromatic – from aroma – a number of these compounds have strong and sometimes pleasant odors. 245

67. Aromatic Compounds Aromatic – from aroma – a number of these compounds have strong and sometimes pleasant odors. The most important compound in this family is benzene. 246

68. Benzene C 6 H 6 This is a very important example in organic chemistry – an example of resonance: C C C C C C C C C C C C 247

69. The two resonance structures are averaged leading to the following structure: C C C C C C 248

70. If resonance were not important for benzene, i.e. only one of the two preceding resonance structures were required to describe the structure of benzene, then we might expect benzene to have a reactivity similar to 249

71. If resonance were not important for benzene, i.e. only one of the two preceding resonance structures were required to describe the structure of benzene, then we might expect benzene to have a reactivity similar to CH 2 CH CH CH CH CH 2 250

72. If resonance were not important for benzene, i.e. only one of the two preceding resonance structures were required to describe the structure of benzene, then we might expect benzene to have a reactivity similar to CH 2 CH CH CH CH CH 2 1,3,5-hexatriene 251

73. If resonance were not important for benzene, i.e. only one of the two preceding resonance structures were required to describe the structure of benzene, then we might expect benzene to have a reactivity similar to CH 2 CH CH CH CH CH 2 1,3,5-hexatriene This is not the case! 252

74. If resonance were not important for benzene, i.e. only one of the two preceding resonance structures were required to describe the structure of benzene, then we might expect benzene to have a reactivity similar to CH 2 CH CH CH CH CH 2 1,3,5-hexatriene This is not the case! 1,3,5-hexatriene is fairly reactive with a variety of reagents (e.g. HBr, Cl 2, etc. in the dark). These reagents react only slowly with benzene. 253

75. Benzene is more stable than might be expected by examination of the individual resonance structures. 254

76. Naming benzene compounds 255

77. Naming benzene compounds chlorobenzene 256

78. 1,2-dibromobenzene 257

79. 1,2-dibromobenzene 1,3-dibromobenzene 258

80. 1,2-dibromobenzene 1,3-dibromobenzene 1,4-dibromobenzene 259

81. o-dibromobenzene m-dibromobenzene p-dibromobenzene 260

82. o-dibromobenzene m-dibromobenzene o = ortho m = meta p = para p-dibromobenzene 261

83. Steroids 262

84. 263

85. 264

86. IUPAC name (10R, 13R)-10,13-dimethyl-17-(6-methylheptan-2- yl)-2,3,4,7,8,9,11,12,14,15,16,17-dodecahydro-1H- cyclopenta[a]phenanthren-3-ol 265

87. 266

88. 267

89. 268

90. 269 oral contraceptive

91. 270

92. 271

93. Theobromine (replace the CH 3 at the arrow by H) is the stimulant found in 272

94. Theobromine (replace the CH 3 at the arrow by H) is the stimulant found in chocolate. 273

95. 274

96. 275

97. 276

98. Stereochemistry 277

99. Stereochemistry Stereochemistry: Deals with the 3- dimensional arrangement of atoms in space for a particular chemical structure. 278

100. Stereochemistry Stereochemistry: Deals with the 3- dimensional arrangement of atoms in space for a particular chemical structure. It also deals with how molecules react in 3- dimensions. 279

101. Isomers 280

102. Isomers Two or more compounds with the same molecular formulas but different arrangements of the atoms in space. 281

103. Isomers Two or more compounds with the same molecular formulas but different arrangements of the atoms in space. Three different types of isomerism will be considered. 282

104. Isomers Two or more compounds with the same molecular formulas but different arrangements of the atoms in space. Three different types of isomerism will be considered. 1. Structural isomers (constitutional isomers) 283

105. Isomers Two or more compounds with the same molecular formulas but different arrangements of the atoms in space. Three different types of isomerism will be considered. 1. Structural isomers (constitutional isomers) 2. Geometric isomers 284

106. Isomers Two or more compounds with the same molecular formulas but different arrangements of the atoms in space. Three different types of isomerism will be considered. 1. Structural isomers (constitutional isomers) 2. Geometric isomers 3. Optical isomers 285

107. Structural isomers 286

108. Structural isomers Structural isomers (constitutional isomers): Compounds with the same molecular formulas but different arrangements of the atoms. 287

109. Structural isomers Structural isomers (constitutional isomers): Compounds with the same molecular formulas but different arrangements of the atoms. Example: Draw the structural isomers for C 4 H 10 288

110. CH 3 CH 2 CH 2 CH 3 butane 289

111. CH 3 CH 2 CH 2 CH 3 butane CH 3 CHCH 3 2-methylpropane CH 3 (the 2 is redundant in this name) 290

112. Example: Draw the structural isomers for C 5 H 12 291

113. Example: Draw the structural isomers for C 5 H 12 CH 3 CH 2 CH 2 CH 2 CH 3 pentane 292

114. Example: Draw the structural isomers for C 5 H 12 CH 3 CH 2 CH 2 CH 2 CH 3 pentane CH 3 CH 2 CHCH 3 2-methylbutane CH 3 (2 is redundant) 293

115. Example: Draw the structural isomers for C 5 H 12 CH 3 CH 2 CH 2 CH 2 CH 3 pentane CH 3 CH 2 CHCH 3 2-methylbutane CH 3 (2 is redundant) CH 3 CH 3 CCH 3 2,2-dimethylpropane CH 3 (each 2 is redundant) 294

116. 295

117. 296

118. Example: Draw the structural isomers for C 2 H 6 O 297

119. Example: Draw the structural isomers for C 2 H 6 O CH 3 CH 2 OH ethanol 298

120. Example: Draw the structural isomers for C 2 H 6 O CH 3 CH 2 OH ethanol CH 3 OCH 3 methoxymethane (dimethyl ether) 299

121. Exercise: Draw and name all the structural isomers for C 6 H 14 (Answer there are 5). 300

122. Exercise: Draw and name all the structural isomers for C 6 H 14 (Answer there are 5). The number of structural isomers increases significantly as the number of carbon atoms increases. For example, C 20 H 42 has 366,319 isomers. 301

123. Number of carbons Number of isomers for alkanes 1 1 2 1 3 1 4 2 5 3 6 5 7 9 8 18 9 35 10 75 20 366,319 30 4,111,846,763 40 62,491,178,805,831 302

124. Stereoisomerism 303

125. Stereoisomerism Stereoisomerism: Isomers having the same molecular formula and the same atom-to- atom bonding, but the atoms differ in their arrangement in space. 304

126. Stereoisomerism Stereoisomerism: Isomers having the same molecular formula and the same atom-to- atom bonding, but the atoms differ in their arrangement in space. Geometric isomers: Isomers having the same atom-to-atom bonding, but the atoms differ in their arrangement in space. 305

127. Examples: The trans and cis isomers of 1,2-dichloroethene. 306

128. Examples: The trans and cis isomers of 1,2-dichloroethene. trans- 1,2-dichloroethene. 307

129. Examples: The trans and cis isomers of 1,2-dichloroethene. trans- 1,2-dichloroethene. cis- 1,2-dichloroethene. 308

130. Examples: The trans and cis isomers of 1,2-dichloroethene. trans- 1,2-dichloroethene. (b.p. 48 o C, m.p. -50 o C) cis- 1,2-dichloroethene. (b.p. 60 o C, m.p. -80 o C) 309

131. An example from inorganic chemistry. NH 3 Cl NH 3 Cl Pt Pt NH 3 Cl Cl NH 3 cis isomer trans isomer 310

132. An example from inorganic chemistry. NH 3 Cl NH 3 Cl Pt Pt NH 3 Cl Cl NH 3 cis isomer trans isomer common name: cisplatin 311

133. An example from inorganic chemistry. NH 3 Cl NH 3 Cl Pt Pt NH 3 Cl Cl NH 3 cis isomer trans isomer common name: cisplatin Only the cis isomer is an effective chemotherapy agent. 312

134. Optical Isomers - Chirality 313

135. Optical Isomers - Chirality Polarized Light: Plane polarized light consists of electromagnetic waves with the electric component vibrating in one direction. 314

136. 315

137. Optical Isomer: An isomer that causes rotation of the plane of polarization of light when passed through the substance. 316

138. 317

139. Chiral (sounds like ki ral): An object that cannot be superimposed on its mirror image is called chiral. 318

140. 319

141. 320

142. mirror plane 321

143. mirror plane Can superimpose these two molecules; trichloromethane is achiral. 322

144. mirror plane 323

145. mirror plane Cannot superimpose these two molecules; bromochlorofluoromethane is chiral. 324

146. Enantiomers: A chiral molecule and its non- superimposable mirror image are called enantiomers. 325

147. Enantiomers: A chiral molecule and its non- superimposable mirror image are called enantiomers. The simplest case is a tetrahedral carbon bonded to four different groups. 326

148. Enantiomers: A chiral molecule and its non- superimposable mirror image are called enantiomers. The simplest case is a tetrahedral carbon bonded to four different groups. Chiral molecules lack molecular symmetry. 327

149. 328

150. Lactic acid has optical isomers. 329

151. One optical isomer is sometimes represented by a D (for dextrorotatory: Latin dexter, right) if the rotation of the plane of polarization is to the right; or L (for levorotatory: Latin laevus, left), if the rotation of the plane of polarization is to the left. 330

152. One optical isomer is sometimes represented by a D (for dextrorotatory: Latin dexter, right) if the rotation of the plane of polarization is to the right; or L (for levorotatory: Latin laevus, left), if the rotation of the plane of polarization is to the left. The symbols + for rotation to the right and - rotation to the left, are also fairly commonly used. 331

153. One optical isomer is sometimes represented by a D (for dextrorotatory: Latin dexter, right) if the rotation of the plane of polarization is to the right; or L (for levorotatory: Latin laevus, left), if the rotation of the plane of polarization is to the left. The symbols + for rotation to the right and - rotation to the left, are also fairly commonly used. The lactic acid from muscle tissue is D -lactic acid or (+)-lactic acid. 332

154. A 50:50 mixture of the + and – isomers of the same compound is called a racemic mixture. There is no rotation of the plane of polarization for a racemic mixture. 333

155. Polymers 334

156. Polymer: (Greek: poly meros many parts) 335

157. Polymer: (Greek: poly meros many parts) Very large molecules with molar masses ranging from thousands to millions. 336

158. Polymer: (Greek: poly meros many parts) Very large molecules with molar masses ranging from thousands to millions. Applications: clothes, food packaging, appliances with plastic components, etc., etc., …. Plastics are polymers. 337

159. Two basic types of polymer: 338

160. Two basic types of polymer: 1. Thermoplastics: When heated these soften and flow, when cooled, they harden again. This process can be repeated. 339

161. Two basic types of polymer: 1. Thermoplastics: When heated these soften and flow, when cooled, they harden again. This process can be repeated. Examples: polyethylene and polystyrene 340

162. Two basic types of polymer: 1. Thermoplastics: When heated these soften and flow, when cooled, they harden again. This process can be repeated. Examples: polyethylene and polystyrene 2. Thermosetting plastics: When first heated they are plastic, but further heating forms a highly cross-linked structure. Cannot be softened by reheating. 341

163. Two basic types of polymer: 1. Thermoplastics: When heated these soften and flow, when cooled, they harden again. This process can be repeated. Examples: polyethylene and polystyrene 2. Thermosetting plastics: When first heated they are plastic, but further heating forms a highly cross-linked structure. Cannot be softened by reheating. Example: formica. 342

164. Monomers: The small (low molar mass) molecules used to synthesize polymers. 343

165. Synthetic Polymers 344

166. Synthetic Polymers Two principal reaction types: Addition and condensation. 345

167. Synthetic Polymers Two principal reaction types: Addition and condensation. Addition Polymers: Made by monomer units directly joining together. 346

168. Synthetic Polymers Two principal reaction types: Addition and condensation. Addition Polymers: Made by monomer units directly joining together. Condensation Polymers: Made by monomer units combining so that a small molecule, usually water, is split out. 347

169. Addition Polymers 348

170. Addition Polymers The monomer for addition polymers normally contains one or more double bonds. 349

171. Addition Polymers The monomer for addition polymers normally contains one or more double bonds. The polymerization reaction is initiated using an organic peroxide. 350

172. Addition Polymers The monomer for addition polymers normally contains one or more double bonds. The polymerization reaction is initiated using an organic peroxide. R O O R R O. +. O R 351

173. Addition Polymers The monomer for addition polymers normally contains one or more double bonds. The polymerization reaction is initiated using an organic peroxide. R O O R R O. +. O R organic peroxide free radicals 352

174. Initiation step: +. OR. 353

175. Initiation step: +. OR. 354

176. Then 355

177. Etcetera: where n would typically range from 1000 to 50,000. 356

178. Different experimental conditions give different polymers. 357

179. Different experimental conditions give different polymers. 358

180. Different experimental conditions give different polymers. + 359

181. Different experimental conditions give different polymers. + branched polymer chain 360

182. Cross linked polymers are formed in the following manner: 361

183. Cross linked polymers are formed in the following manner: 362

184. Cross linked polymers are formed in the following manner: 363

185. Cross linked polymers are formed in the following manner: 364

186. Cross linked polymers are formed in the following manner: 365

187. 366

188. 367

189. cross linked polymer 368

190. Polyethylene is the most widely used polymer. 369

191. Polyethylene is the most widely used polymer. The long linear chain version is called high density polyethylene (HDPE) (d = 0.97 g/ml). 370

192. Polyethylene is the most widely used polymer. The long linear chain version is called high density polyethylene (HDPE) (d = 0.97 g/ml). It is hard, tough, and rigid. Used for milk and detergent containers. 371

193. The branched chain version is called low density polyethylene (LDPE) (d=0.92 g/ml). The branched chains of polyethylene prevent close packing – hence the density is lower. 372

194. The branched chain version is called low density polyethylene (LDPE) (d=0.92 g/ml). The branched chains of polyethylene prevent close packing – hence the density is lower. This polymer is soft and flexible. Used for grocery bags, bread bags, etc. 373

195. The cross linked polymer is called cross-linked polyethylene (CLPE). This is a very tough material. Used for plastic caps on soft drink bottles. 374

196. 375

197. Condensation Polymers 376

198. Condensation Polymers A condensation reaction occurs when two molecules react by splitting out or eliminating a small molecule such as water. 377

199. Ester formation reaction: CH 3 CO 2 H + CH 3 CH 2 OH CH 3 CO 2 CH 2 CH 3 + H 2 O acetic acid ethanol ethyl acetate

200. Polyesters 379 terephthalic acid ethylene glycol +22 +2 H 2 O

201. Polyesters 380 terephthalic acid ethylene glycol +22 +2 H 2 O Now consider another terephthalic acid molecule reacting with the indicated alcohol functional group.

202. 381 This is an example of the repeat unit for a polyester. In this case it is poly(ethylene terephthalate) called PET.