2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P. Atkins / L. Jones, Chemical Principles, 4th ed., Freeman (2008) Chapter 19 CHAPTER 19 ORGANIC CHEMISTRY II: POLYMERS AND BIOLOGICAL COMPOUNDS COMMON FUNCTIONAL GROUPS 19.1 Haloalkanes R–X ◈ Nucleophilic substitution reaction (친핵치환반응,親核置換反應) Æ C–X bond is polar Æ Nucleophile replaces X – Ex: OH ion (– charge), H2O (lone pair) Æ Hydrolysis in EtOH(aq) solution −− CH33Br +⎯OH ⎯→+CH OH Br 19.2 Alcohols R–OH ◆ –OH group, –ol Ex: CH3OH: methanol (methyl alcohol) C2H5OH: ethanol (ethyl alcohol) CH3CH2CH2OH: 1-propanol CH3CH(OH)CH3: 2-propanol CH3CH(OH)CH2CH3: Fig. 19.1 The charge distribution in 2-butanol or 2-hydroxybutane an ethanol molecule. Æ Less volatile than alkanes due to hydrogen bonds: Ex: ethanol(l) vs. butane(g) 1 2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P. Atkins / L. Jones, Chemical Principles, 4th ed., Freeman (2008) Chapter 19 ◆ Classification of alcohols according to the number of organic groups attached to the C atom connected to the –OH group: Primary alcohol: RCH2–OH ex: ethanol Secondary alcohol: R2CH–OH ex: 2-butanol Tertiary alcohol: R3C–OH ex: 2-methyl-2-propanol, (CH3)3COH or tertiary-butyl alcohol or tert-butanol ◆ Synthesis of alcohols Æ Nuclear substitution of haloalkanes ▶ Methanol o CO(gg) + 2 H ( ) ⎯catal⎯⎯⎯⎯⎯⎯⎯⎯yst, 250 C,50-100 atm⎯→CH OH(g) 23 synthesis gas Catalyst: mixture of Cu, ZnO, Cr2O3 ▶ Ethanol • Fermentation of carbohydrates. • Hydration of ethane o HP34O, 300C CH22=CH (gg) + H2O( ) ⎯⎯⎯⎯⎯⎯→CH3CH2OH ▶ Ethylene glycol 1,2-ethanediol Diol, two –OH groups Antifreeze component Synthetic fiber 1,2-ethanediol, HOCH2CH2OH 19.3 Ethers R – O – R’ CH32CH −−O CH2CH3, diethyl ether Lower boiling points than alcohols due to lack of hydrogen bonds Fig. 19.2 The lower boiling points of ethers than those of alcohols. 2 2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P. Atkins / L. Jones, Chemical Principles, 4th ed., Freeman (2008) Chapter 19 ▶ Crown ethers : cyclic ethers, Pedersen (1960) 18-crown-6 (1,4,7,10,13,16-hexaoxacyclooctadecane) m–crown–n m: number of atoms in the cycle 18-crown-6 n: number of O atoms Strong binding with metal cations Æ ‘Trojan horse’ for K+ ions Æ soluble in nonpolar sovents 18-crown-6-K Ex. KMnO4(crown ether) ★ Nobel Laureates in Chemistry (1987) "for their development and use of molecules with structure-specific interactions of high selectivity" 出生地: 釜山 父: Norwegian marine engineer Steam-ship to far-east (釜山) Worked at Custom service Worked at Unsan mine Donald J. Cram Jean-Marie Lehn (美,1919-2001) (佛,1939 - ) (平北 雲山金鑛, 미국인 채굴권) Charles J. Pedersen (美,1904-1989) 母: Japanese ◆ Phenols ▶ Phenol, C6H5OH or Carbolic acid Weak acid, but stronger than EtOH Partial oxidation of benzene, Distillation of coal Toxic: lethal dosage,1g WWII Reaction with chlorine in tap water Æ foul smell of C6H5Cl Contamination of Nakdong river in 1991 3 2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P. Atkins / L. Jones, Chemical Principles, 4th ed., Freeman (2008) Chapter 19 ▶ Substituted phenols Essential oils: concentrated, hydrophobic liquids containing volatile aroma compounds from plants. Thymol: Oil of thyme Eugenol: Oil of clove Distillation of herbal plants Used for cosmetics, perfumes – ▶ Resonance structures of phenoxide ion, C6H5O ←⎯→ ←⎯→ ←⎯→ Æ Conjugate base of phenol stabilizes the anion 4 2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P. Atkins / L. Jones, Chemical Principles, 4th ed., Freeman (2008) Chapter 19 – Æ Weaker conjugate base than ethoxide, CH3CH2O Æ Phenol is insoluble in water but soluble in basic solution. ☻ Phenyl methanol, C6H5CH2OH: Benzyl alcohol Æ alcohol, not a phenol 19.4 Aldehydes and Ketones ◆ Aldehyde: –al ▶ Formaldehyde, HCHO methanal 600o C, Ag 2 CH32OH(gg) +⎯O ( ) ⎯⎯⎯⎯→+2 HCHO(g) 2 H2O(g) Destructive effect on bacteria Wood smoke contains HCHO Æ preservation of smoked foods (훈제,燻製) “Formalin” : aqueous solution of HCHO Æ preservation of biological specimens Sick house syndrome (새집증후군,새집症候群) ► Tollens test: ‘Silver mirror’ formation by aldehyde + CH32CH CHO(g) + Ag (in Tollens reagent) ⎯⎯→+CH32CH COOH Ag(s) Tollens reagent: ammoniacal silver nitrate [Ag(NH3)2]NO3 (aq) aldehyde ketone Fig.19.3 The results of Tollens test ▶ Acetaldehyde, CH3CHO ethanal ▶ Aldehydes in essential oils cherry, almond cinnamon (계피,桂皮) vanilla 5 2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P. Atkins / L. Jones, Chemical Principles, 4th ed., Freeman (2008) Chapter 19 ◆ Ketone: –one ▶ Acetone, propanone Good solvent, miscible with water Oxidation of secondary alcohol: CH3CH(OH)CH3(aq) + NaOCl (aq) ⎯⎯→ CH3(CO)CH3 (aq) + NaCl (aq) + H2O (l) ▶ Other ketones: CH3CH2CH2COCH3, 2-pentanone CH3CH2COCH2CH3, 3-pentanone ☻ No reaction with Tollens reagent 19.6 Carboxylic Acids, R–COOH, -oic acid ▶ Carboxyl group, ◆ Formic acid, HCOOH metanoic acid ◆ Acetic acid, CH3COOH ethanoic acid ▶ Oxidation of primary alcohols and aldehydes with a strong oxidizing agent, acidic KMnO4(aq) ▶ Direct oxidation of alkyl groups to carboxyl group RC−−O−R' 19.7 Ester, || , -oate O Æ Product of the reaction between a carboxylic acid and an alcohol Æ Fragrant odors, flavors of fruits ▶ Ethyl acetate, ethyl ethanoate 6 2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P. Atkins / L. Jones, Chemical Principles, 4th ed., Freeman (2008) Chapter 19 ←⎯→ ▶ Benzyl acetate, CH3COOCH2C6H5 Å Oil of jasmine ▶ Tristearin, C57H110O6 Å animal fat Product of the reaction between glycerol and stearic acid, CH3(CH2)16COOH ◆ Condensation reaction Fig. 19.4 Two molecules are linked in a condensation reaction. ★ Trans fats (트랜스지방脂肪) ► Hydrogenation of oils (ester of cis-unsaturated fatty acids) Æ saturated fats with higher m. p. : solid, good for baking and extended shelf-life Æ remaining double bonds converted from cis to trans isomers Å bad for health! ► Transesterification (에스터교환): Switching of the long carboxylic acid chains from one alcohol location to another in a fatty acid by an enzyme. Å acid catalyst Æ double bonds remained with high m.p. but no trans fats 7 2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P. Atkins / L. Jones, Chemical Principles, 4th ed., Freeman (2008) Chapter 19 19.8 Amines, Amino Acids, and Amides | ◆ Amines: R–NH2 (primary), R–NH–R’ (secondary), N (tertiary) / \ ammonia methylamine dimethylamine trimethylamine (primary) (secondary) (tertiary) ► Quaternary ammonium ions: tetrahedral structure + Tetramethylammonium ion, (CH3)4N + Trimethylammonium ion, (CH3)3NH ► Functional group: amino group, –NH2 ► Weakly basic except quaternary ammonium ions ► Foul smell of decaying flesh (along with sulfur compounds) putrescine, NH2(CH2) 4H2 cadaverine, NH2 (CH2) 5NH2 ☻ putrefy : 부패시키다 ☻ cadaver: (해부용)시체(屍體) ◆ Amino Acids NH2 – R – COOH Æ Carboxylic acids containing an amino group (basic) and a carboxyl group (acidic) ▶ Glycine NH2CH2COOH α -amino acid + – “Zwitterion” in aqueous solution (pH=7): H3NCH2CO2 ▶ Alanine CH3CH(NH2)COOH α -amino acid + + – – NH3CH(CH2)COOH Æ NH2CH(CH2)COOH ( NH3CH(CH2) CO2 ) Æ NH2CH(CH2) CO2 acidic solution neutral solution basic solution 8 2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P. Atkins / L. Jones, Chemical Principles, 4th ed., Freeman (2008) Chapter 19 Fig. 19.5 The fractional composition of alanine species as a function of pH. γ β α ▶ GABA (gamma-aminobutyric acid): NH22C H C H2C H2COOH Æ γ -amino acid Æ One of Neurotransmitters (신경전달물질): GABA, Dopamine, Acetylcholine, … ◆ Amide Æ Condensation product of an amine with a carboxylic acid R – (CO) – NHR’ from a primary amine ⎯⎯→ ▶ Mechanism of amide formation (1) An amine (base) accepts a proton from a carboxylic acid, forming quaternary ammonium salt. − + CH33COOH +⎯CH NH2⎯→+CH3CO2CH3NH3 (2) Upon heating to 200oC, Attacking of amine (nucleophile) to the carboxyl carbon Æ Reverse proton transfer ⎯⎯→ ⎯⎯→ ⎯⎯→ 9 2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P. Atkins / L. Jones, Chemical Principles, 4th ed., Freeman (2008) Chapter 19 Caprolactam Nylon-6 Å polyamide Ex. 19.1 Naming compounds with functional groups 3-methyl-2-butanol 4-chloro-2-pentanone diethylpropylamine CH3CH(CH3)CH(OH)CH3 CH3CHClCH2COCH3 (CH3CH2) 2NCH2CH2CH3 THE IMPACT ON MATERIALS ◈ Macromolecules ◆ Polymers: chains or networks of small repeating units forming giant molecules Æ Made by addition reaction and condensation reaction 19.9 Addition Polymerization ◆ Alkenes: Ex: Ethene (monomer, repeating unit) Æ Polyethylene, – (CH2CH2)n – ◆ Substituted ethene monomer, CHX=CH2 X=Cl : CHCl=CH2, vinyl Æ Polyvinyl chloride (PVC), – (CHClCH2)n – X=CH3 : CH3CH=CH2, propene Æ Polypropylene, – (CH(CH3)CH2)n – 10 2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P. Atkins / L. Jones, Chemical Principles, 4th ed., Freeman (2008) Chapter 19 ◆ Radical polymerization ● Initiation: ● Propagations: ● Termination: no more monomers, linkage of two radical chains ★ Problem ! : Random orientation and side-chain growth of polypropylene Æ Poor packing ▶ Ziegler-Natta catalyst : TiCl4 + (CH3CH2)3Al Fig. 19.6 Substituents in a polymer with (a) random and (b) stereoregular (with Z-N catalyst) orientations. 11 2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P. Atkins / L. Jones, Chemical Principles, 4th ed., Freeman (2008) Chapter 19 ★ Nobel Laureate in Chemistry (1963) "for their discoveries in the field of the chemistry and technology of high polymers" Karl Ziegler Giulio Natta (獨,1898-1973) (伊,1903-1979) ● Ziegler: organoaluminum compound catalyst Æ control polymerizations and to obtain molecular chains of the required length ● Natta: Æ a certain Ziegler catalyst leads to a steroregular isotactic polymer Å High-density polymer Å The floating PE, produced from high pressure polymerization. Å The bottom one, produced with a Z-N catalyst. Fig. 19.7 The two samples of polyethylene in a test tube. ▶ Rubber: a polymer of isoprene Isoprene Fig. 19.8 Collecting latex from a rubber tree. ► Natural rubber: obtained from latex from the bark of rubber tree ► Artificial rubber: obtained with Z-N catalyst Æ cis-polyisoprene Naturally occurring material, “gutta-percha” (a plant’s name in Malay, “getah perca”) Æ trans-polyisoprene (golf ball, filling dental canals) 12 2009년도 제2학기 화 학 2 담당교수: 신국조 Textbook: P.