CHAPTER OUTLINE. I. Elemental Carbon II. Crude Oil : the Basic Resource III. Hydrocarbons IV. Separating Hydrocarbons by Fractional Distillation

Transcription

1 Carbon Chapter 12 CHAPTER UTLINE 9.2 I. Elemental Carbon II. Crude il : the Basic Resource III. Hydrocarbons IV. Separating Hydrocarbons by Fractional Distillation V. Processing Hydrocarbons VI. Typical Reactions of the Alkanes VII. The Functional Group Concept VIII. Ethene, the C=C Bond, and Polymers IX. Alcohols X. From Alcohols to Aldehydes, Ketones, and Carboxylic Acids XI. From Alcohols l and Carboxylic Acids to Esters XII. Condensation Polymers XIII. Polyethers XIV. Handedness in Molecules XV. rganic Chemistry and Modern Drug Discovery A. Taxol 1 2

2 What we Learn from Chap This chapter on the chemistry of carbon has the capacity to be the most applied one in the textbook because carbon is the basis of life, and sustains our industrialized life through crude oil, its derivatives, and products. We therefore approached the discussion from two standpoints; the first is a global one, which considers the processing and uses of oil and coal, and the second, discusses functional groups, which occur both naturally and as derivatives from crude oil. Throughout the chapter, we retain the over-arching chemistry theme that structure and properties are deeply connected. We open the chapter pointing out that oil and coal are carbon-based compounds and currently meet many of our energy and lifestyle needs. 1 3 rganic Compounds

3 12.1 Elemental Carbon -Allotropes of Carbon- 9.5 Diamond Tetrahedral network of covalently bonded atoms. Graphite a hexagonal network of atoms in layers. Fullerenes derivatives of C 60 in a geodesic dome structure Crude il

4 12.3 Hydrocarbons 9.7 Contain only carbon and hydrogen atoms. Saturated hydrocarbons (aliphatic) contain atoms of carbon bonded d to as many hydrogens as possible. Straight-chain Branched Cyclic 1 7 Alkanes 9.8 Single bonded carbons. Saturated with hydrogen. General formula: C n H 2n+2 May form straight chains (normal alkanes) branched chains or rings (C n H 2n ). -CH 2 - : methylene group Homologous group C: sp 3 hybrid orbital 1 8

5 Alkanes Isomers 9.10 Structural isomers : same formula but differ in the way of the atoms are attached Straight chain H 3 C-CH 2 -CH 2 -CH 2 -CH 3 ne isomer is: H 3 C CH 2 CH CH 3 CH

6 Practice 12.1) Isomer of heptane Naming Alkanes Name the longest straight chain using suffix ane. 2. Name the branch using the alkane name but change ane to yl (for example: two carbon ethane becomes ethyl). 3. Number the branch with the lowest possible number. 1 12

7 Sample Problem 9.13 Name the following alkane: H 3 C CH 2 CH CH 3 CH 3 2-methylbutane 1 13 Sample Problem 9.14 Name the following alkane: H 3 C CH 2 CH CH 2 CH CH 2 CH 2 CH 3 CH 3 CH3 3,5-dimethyloctane 1 14

8 Cyclic Alkanes Alkenes 9.16 Unsaturated t hydrocarbons Hydrocarbons containing at least one carboncarbon double bond. General formula is C n H 2n Named like alkanes except suffix is ene and double bond is given the lowest number. hydrogenation 1 16

9 Alkenes Alkynes 9.18 Hydrocarbons containing at least one carbon-carbon triple bond. General formula is C n H 2n-2 Named like alkenes except suffix is yne and triple bond is given the lowest number. Ethyne(acetylene), propyne, 1-Butyne 1 18

10 Geometric Isomers 9.19 H C CH H C 3 H 3 3 C C C C H H H CH 3 cis-2-butene trans-2-butene 1 19 Ex) A trans fatty acid 1 20

11 Aromatic Hydrocarbons Alkyl Groups 9.22 Alkyl groups are named from the alkane base. CH 3 methyl group C 2 H 5 ethyl group C 3 H 7 propyl group C 4 H 9 butyl group C 5H 11 pentyl group 1 22

12 12.4 Separating Hydrocarbons by Fractional Distillation Fractional Distillation

13 12.5 Processing Hydrocarbons 9.25 Cracking : breaking long-chain hydrocarbons into smaller ones thermal - heat alone. catalytic - uses a catalyst and heat. hydrocracking heat, a catalyst t in the presence of hydrogen. steam heat, steam and a catalyst Reforming :Convert into more useful forms (more aromatic & branched-chain chain HC) To avoid knocking 1 25 Gasoline 9.26 C5~C9 ctane value CH 3 CH 3 CH 3 CH 2 CH 2 CH 2 CH 2 CH 2 CH 3 CH 3 H 3 C C CH 2 C CH 3 H CH 3 Heptane (octane number = 0) bad fuel Isooctane (octane number = 100) good fuel ctane value 90 = isooctane 90% : heptane 10% Branched HC are more resistant to radical formation than straight chain HC. C-H in CH 3 - (423kJ) vs in CH 2 - (410kJ) 1 26

14 12.6 Typical Reactions of the Alkanes Substitution Reaction Cl Cl Cl h 2 + Free radical formation : Dehydrogenation 1 28

15 12.7 Functional Groups Functional Groups (cont.)

16 Practice 12.5) tyrosine Polymers 9.32 Polymerization of ethene forms polyethylene Monomer, polymer, HDPE vs. LDPE 1 32

17 Addition Polymer 9.33 Linear Polymer : CH 2 CH 2 (CH 2 ) n CH 2 CH 2 CH 2 : A section of polyethylene Branched Polymer : CH 2 CH(CH 2 )nch 2 CHCH 2 n (CH 2 ) n CH 3 (CH 2 ) n CH 3 n n 1 33 Polymers

18 12.9 Alcohols From Alcohols to Aldehydes, Ketones and Carboxylic Acids 9.36 xidation of primary alcohols leads to the formation o of aldehydes, while secondary alcohols o yield ketones. H oxidation 3 C CH 2 CH 2 H H 3 C CH 2 C H propanol 1 alcohol H 3 C CH 2 CH CH 3 H 2-butanol 2 alcohol oxidation propanal H 3 C CH 2 C CH 3 2-butanone 3 alcohol (xidation?) No reaction 1 36

19 9.37 From Alcohols to Aldehydes, Ketones and Carboxylic Acids Both aldehydes and ketones can be further oxidized to a carboxylic acid. H C H methanal oxidation H C H methanoic acid CH C H CH C H 3 3 Ethanoic acid Ethanoate From Alcohols and Carboxylic Acids to Esters 9.38 Reaction of a carboxylic acid with an alcohol forms an ester. H 3 C C H + H 3 C CH 2 H H 3 C C CH 2 CH 3 ethanoic acid ethanol ethyl ethanoate + H

20 Naming of esters Condensation Polymers 9.40 H(CH 2 ) n H + H C (CH 2 ) n C H (CH 2 ) n C (CH 2 ) n C -H A diol A diacid 2 A polyester Amide bond H 2 N(CH 2 ) n NH 2 + Cl C (CH 2 ) n C Cl HN(CH 2 ) n NH C (CH 2 ) n C A diamine A diacid chloride A polyamide(nylon) -HCl 1 40

21 12.13 Polyethers 9.41 Polymers containing C C linkage. Epoxy resins are examples of polyethers Condensation Polymer

22 Nylon Handedness in Molecules 9.44 Chiral compounds have nonsuperimposable mirror images. Chiral carbons have four different groups attached to them. left hand with right glove right hand with left glove 1 44

23 Chiral Molecules 9.45 The two mirror images of a chiral molecule are stereoisomers. Chiral molecules have the ability to rotate polarized light Enantiomer 9.46 Enantiomer : same physical & chemical propertiesp CHClBrI H H H H 3 C C CH HC C H CH 3 (+)-Lactic acid (-)-Lactic acid 1 46

24 Chirality in Nature 9.47 (+) lactic acid, [a] D = ; (-) lactic acid, [a] D = cf) racemic mixture Penicillin V Sucrose Camphor Monosodium glutamate [ ] D o Cholesterol o Morphine o Acetic acid o Benzene [ ] D o -132 o 0 0 o 0 o - the values and sighs of specific rotations depend on the types of compounds ; in general, unpredictable Chirality in Nature Enantiomers have the same physical properties, they usually have different biological properties. (+)-Limonene (in oranges) (-)-Limonene (in lemons) 1 48

25 9.49 Aspartame H 2 N C 2 H H N CH 3 H 3 C H 2 C H N NH 2 Aspartame Sweet II Bitter Chiral Drugs NH 2 CH 3 Amphetamine NH 2 Dexedrine CH 3 Me Me H C 2 H Naproxen (anti-inflammatory drug) The first chiral drug (1990s) 1 50

26 Thalidomide Tragedy 's and 60's: racemic thalidomide ( 입덧치료 ) N N N H N H (-)-S-Thalidomide Sedative ( 입덧치료제 ) (+)-R-Thalidomide 기형유발제 1 51 Modern Drug Discovery 9.52 rganic chemistry has a major impact on the pharmaceutical industry. The Taxol story. 1 52

27 Taxol 9.53 A biosynthetic intermediate 1g/Kg-needles Purification from the bark of the Pacific yew tree Synthesis from readily available materials Total synthesis 1 53 Problems , 14, 20, 30,40,64,70, 80, 86,96,