Vast majority of over 20 million known compounds are based on C: Generally contain C and H + other elements Great variety of compounds

Transcription

1 1

2 Vast majority of over 20 million known compounds are based on C: Generally contain C and + other elements Great variety of compounds 2

3 3 Isomers have identical composition but different structures Two forms of isomerism Constitutional (or structural) Stereoisomerism Constitutional Same empirical formula but different atom- to-atom connections Stereoisomerism Same atom-to to-atom connections but different arrangement in space.

4 4

5 5! Geometric isomers can occur when there is a C=C double bond. Cis-2-butene Trans-2-butene

6 6! are molecules with non-superimposable mirror images. Such molecules are called " Pairs of chiral molecules are. Chiral molecules in solution can rotate the plane of plane polarized light.

7 7 # $ %"#

8 8 Chirality generally occurs when a C atom has 4 different groups attached. Lactic acid

9 9 Lactic acid isomers are nonsuperimposable

10 #! 10 These molecules are non-superimposable mirror images.

11 #! 11 These amino acids are non- superimposable mirror images.

12 12 Right- and left- handed seashells The DNA here is right-handed handed

13 13 & Compounds of C and Subgroups: Alkanes: : C-C C C single bonds Alkenes: C=C double bonds Alkynes: carbon-carbon triple bonds Aromatic: based on benzene

14 14 & Alkanes have the general formula C n 2n+2 C 4 = methane C 2 6 = ethane C 3 8 = propane C 4 10 = butane C 5 12 = pentane

15 15

16 # ' ( ) * +, 16

17 # ' ( ) * +, 17

18 18 # ' ( ) * +, Gas hydrates have been known for many years, and combustion of a sample of methane hydrate is seen on the front cover. Recently, however, vast deposits of methane hydrate were discovered deep within sediments on the floor of the world s oceans. ow these deposits were formed is a mystery. But what is important is their size. It is estimated that the global methane hydrate deposits contain approximately tons of carbon, or about twice the combined amount in all reserves of coal, oil, and conventional natural gas. Now if scientists and engineers could only solve the problem of extracting the methane conveniently and safely!

19 C 3 C 2 C 2 C 2 C 3 Pentane C 3 C 3 CC 2 C 3 2-Methylbutane 19 & - Isomers of C 5 12? C 3 3 CCC 3 C 3 2,2-Dimethylpropane Note names of isomers C 5 12 has 3 structural isomers. C 6 14 has 5 C 7 14 has 9

20 20 &!. Alkanes are colorless gases, liquids, and solids Generally unreactive (but undergo combustion) Not polar (or low polarity) and so are not soluble in water.

21 &!. 21 All compounds are flexible. Cyclohexane,, C 6 12, has interconverting chair and boat forms. Axial ato m Eq u atorial atom Chair form Boat form Chair form

22 .! /# 22 01& 2 ow many isomers are possible for a compound with the formula C 4 8? 1 2 C C 3 4 C 2 C 3 1 C 2 C 3 C 3 C C 4 4 C 3 C C C C C 1 3 C 1-butene 2-methylpropene (isobutene) cis-2-butene trans-2-butene

23 23.3

24 .! Alkenes are more bonds can form to the C atoms Molecules such as Br 2, 2, Cl, Br,, and 2 to the double bond C C + Br 2 Br Br C C 1,2-dibromoethane

25 25 Fat placed in Br 2 vapor The fat in bacon is partially unsaturated. The fat adds Br 2 to the C=C bonds. Fats can be hydrogenated with 2.

26 26 Fat placed in Br 2 vapor

27 27 Fats can be hydrogenated with 2. Peanut butter has partially hydrogenated vegetable oil.

28 . 28 Alkynes have carbon-carbon triple bonds. C 2 2 : common name = acetylene systematic name = ethyne Preparation: CaC 2 (s) + 2 (liq) --> C 2 2 (g) + Ca() 2 (s) o fo (C 2 2, g) = kj/mol rxn rxn for C = 1300 kj/mol

29 29 Benzene, C 6 6, in the top 25 chemicals produced in the U.S. Starting point for hundreds of other compounds.

30 30 2% C 6 6 has two resonance structures with alternating double bonds. The electrons are % over the ring. C C C C C C C C C C C C Resonance structures of benzene, C 6 6 C C C C C C Abbreviated representation of resonance structures

31 31 2% CC bond order is C C C single bond = 154 pm C=C bond = 134 pm CC bonds in benzene = 139 pm electrons delocalized

32 # & 32 Toluene Naphthalene

33 33 2%144 Aniline C 6 5 N 2 Phenol C 6 5 TNT trinitrotoluene C 6 4 C 3 (N 2 ) 3

34 2% Cl rtho to Cl 5 3 Meta to Cl 4 Para to Cl 1,4-dimethylbenzene Common name: Para-xylene

35 35 & not additions are typical. C 3 + C 3 Cl AlCl 3 + Cl AlCl 3 is a catalyst. Catalysts typically used in aromatic substitutions.

36 36 5 See CD-RM Screens 11.5 & 11.6

37 37 # Characterized by group Name: add ol to name of hydrocarbon # 2

38 38 # C 3 5 : how many structural isomers? C C C C C C 1-propanol 2-propanol Naming: Add -ol to name of 3-C 3 C hydrocarbon. Indicate position of with number.

39 39 # $ Alcohols are a derivative of water Many alcohols dissolve in water Methanol dissolves in water. Butanol is NT soluble in water.

40 40 67 Alcohols burn in air A mixture of ethanol + calcium acetate = STERN

41 "" # /#/ 41 Ethylene glycol Propylene glycol

42 42 # Substitution Elimination the the reverse of addition

43 43! # Sugars are carbohydrates, compounds with the formula C x ( 2 ) y α-d-glucose 1 C C β-d-glucose pen chain form What is the difference between α and β D-glucose?

44 44 & α-d-glucose Fructose C 2 C 2 Ribose, a pentose in the DNA backbone

45 45 Alcohols are derivatives of 2 (R ) and are derivatives of N 3. Methylamine Dimethylamine Trimethylamine

46 46 Amines generally have terrible odors! Cadaverine Pyridine

47 47 Amines, like N 3, are bases 2 C 6 5 N 2 (aq) + 2 S 4 (aq) 2 C 6 5 N 3 + (aq) + S 4 2- (aq) Aniline Anilinium ion

48 48 + Nicotine Many natural products and drugs (such as nicotine and cocaine) are bases.

49 C /# & 49 Aldehyde Carboxylic acid Ketone

50 50 # Cinnamaldehyde dors from aldehydes and ketones

51 &, 51 Acetic acid Benzoic acid Acids are found in many natural substances: bread, fruits, milk, wine Carboxylic acid group with acidic + All are WEAK acids

52 &, 52 Formic acid, C 2, gives the sting to ants. C C C 3 Aspirin, acetylsalicylic acid

53 : # ;; ;;< 53 #4

54 : # ;; ;;< 54 C 3 C + C 3 C 2 + C 3 CC 2 C Acetic acid Ethanol Ethyl acetate RC + + R' RC R' + 2 Carboxylic acid Alcohol Ester # =

55 : # ;; ;;< 55 Acetic acid 3-methylbutanol C 3 3 C C C 2 C 2 CC 3 3-methylbutylacetate

56 # /#> 56 Combine this with long chain acids > >??? Fatty acids ---> > fats and oils

57 C CR C CR 2 C CR What is the functional group in a fat or oil? R = organic group with N C=C bonds C 12 = Lauric acid C 16 = Palmitic acid C 18 = Stearic acid C 18 R = organic group with C=C bonds C 18 = oleic acid C 18

58 2 C C 2 C CR CR CR 5 58 Fats with C=C bonds are usually LIQUDS leic acid: a monounsaturated fatty acid C=C bond

59 2 C C 2 C CR CR CR 5 Fats with saturated acids (no C=C bonds) are SLIDS. 59 Saturated fats are more common in animals.

60 60 5$ 2 Bears gorge on blubber in the winter. During the summer bears rely on stored fat for energy. Burn kg of fat per day. Water for metabolism comes from fat burning.

61 61 5 leic acid is a mono unsaturated cis- fatty acid Trans fatty acids have deleterious health effects. Trans fatty acids raise plasma LDL cholesterol and lower DL levels. C=C bond

62 5! Glyceryl stearate, a fat + Na C 2 C C 2 CR CR CR + 3 Na 62 R = (C 2 ) 16 C 3 C 2 C C 2 Glycerol + 3 RC - Na + Sodium stearate, a soap

63 : ;; ;;<1 63 N-methylacetamide

64 : ;; ;;<1 64 C C C C Amide link C N C C C Acetoaminophen Tylenol, Datril,, Momentum,...

65 65 #; 2 N C C Amine R Acid Alanine 3 C C Chiral α-carbon N 3 C 2

66 66 3 N $$ Š C 3 Alanine + C 2 3 N Serine C 2 3 N Š peptide bond N C 3 Adding more peptide links ---> > PRTEIN Š

67 67 $ Giant molecules made by joining many small molecules called Average production is 150 kg per person annually in the U.S.

68 68 $ Thermoplastics (polyethylene) soften and flow when heated Thermosetting plastics soft initially but set to solid when heated. Cannot be resoftened. ther classification: '&' ''#4

69 69 $ $ polymers directly adding monomer units together polymers combining monomer units and splitting out a small water (water)

70 $ #!$ 70 n 2 C C 2 C C Ethylene n Polyethylene A polymer with a molar mass of 1e6 has about 36,0000 units.

71 # $ % 71

72 72 $ # Linear, high density PE (DPE) Branched, low density PE, LDPE Cross-linked PE, CLPE

73 73 $ # Polymers based on Substituted Ethylenes, C 2 =CX C 2 C C 2 C C 2 C n CC 3 n n polyvinyl alcohol polyvinyl acetate polystyrene Table 11.12: others are PVC, acrylonitrile, polypropylene, polymethyl methacrylate

74 $ 74 Polystyrene is nonpolar material and dissolves in organic solvents. PS foam is mostly air, and when it dissolves it collapses to a much smaller volume.

75 75 = Slime is polyvinylalcohol cross-linked with boric acid

76 76 $ n C C + n C 2 C 2 terephthalic acid ethylene glycol C CC 2 C 2 n + 2 Polyethylene terephthalate (PET), a polyester

77 77 $ '$ Jackets made from recycled PET soda bottles Soda bottles, mylar film.

78 $!# 78

79 $! 79

80 80 $! # #9 # $ $

81 81 $ & LDPE = Low density PE = g/cm 3 DPE = igh density PE = PP = Polypropylene = 0.90 V = PVC (Vinyl chloride) =