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Chapter 20 Organic Chemistry 2008, Prentice Hall Chemistry: A Molecular Approach, 1 st Ed. Nivaldo Tro Roy Kennedy Massachusetts Bay Community College.

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Presentation on theme: "Chapter 20 Organic Chemistry 2008, Prentice Hall Chemistry: A Molecular Approach, 1 st Ed. Nivaldo Tro Roy Kennedy Massachusetts Bay Community College."— Presentation transcript:

1 Chapter 20 Organic Chemistry 2008, Prentice Hall Chemistry: A Molecular Approach, 1 st Ed. Nivaldo Tro Roy Kennedy Massachusetts Bay Community College Wellesley Hills, MA

2 Tro, Chemistry: A Molecular Approach2 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)

3 Tro, Chemistry: A Molecular Approach3 Bond Energies and Reactivities

4 Tro, Chemistry: A Molecular Approach4 Allotropes of Carbon - Diamond

5 Tro, Chemistry: A Molecular Approach5 Allotropes of Carbon - Graphite

6 Tro, Chemistry: A Molecular Approach6 Carbon Bonding mainly forms covalent bonds C is most stable when it has 4 single covalent bonds, but does form double and triple bonds C=C and C≡C are more reactive than C−C C with 4 single bonds is tetrahedral, 2 singles and 1 double is trigonal planar 2 doubles or 1 triple and 1 single is linear

7 Tro, Chemistry: A Molecular Approach7 Hydrocarbons hydrocarbons contain only C and H aliphatic or aromatic insoluble in water no polar bonds to attract water molecules aliphatic hydrocarbons saturated or unsaturated aliphatics  saturated = alkanes, unsaturated = alkenes or alkynes may be chains or rings chains may be straight or branched aromatic hydrocarbons

8 8 Uses of Hydrocarbons Number of C atoms StateMajor Uses 1-4gas heating and cooking fuel 5-7 liquids, (low boiling) solvents, gasoline 6-18liquidsgasoline 12-24liquids jet fuel; camp stove fuel 18-50 liquids, (high boiling) diesel fuel, lubricants, heating oil 50+solids petroleum jelly, paraffin wax 1-4gas heating and cooking fuel 5-7 liquids, (low boiling) solvents, gasoline 6-18liquidsgasoline 12-24liquids jet fuel; camp stove fuel 18-50 liquids, (high boiling) diesel fuel, lubricants, heating oil 50+solids petroleum jelly, paraffin wax

9 Tro, Chemistry: A Molecular Approach9 Saturated Hydrocarbons a saturated hydrocarbon has all C-C single bonds it is saturated with hydrogens saturated aliphatic hydrocarbons are called alkanes chain alkanes have the general formula C n H 2n+2

10 Tro, Chemistry: A Molecular Approach10 Unsaturated Hydrocarbons unsaturated hydrocarbons have one of more C=C double bonds or C  C triple bonds unsaturated aliphatic hydrocarbons that contain C=C are called alkenes the general formula of a monounsaturated chain alkene is C n H 2n remove 2 more H for each additional unsaturation unsaturated aliphatic hydrocarbons that contain C  C are called alkynes the general formula of a monounsaturated chain alkyne is C n H 2n-2 remove 4 more H for each additional unsaturation

11 Tro, Chemistry: A Molecular Approach11 Unsaturated Hydrocarbons

12 Tro, Chemistry: A Molecular Approach12 Aromatic Hydrocarbons contain benzene ring structure even though they are often drawn with C=C, they do not behave like alkenes

13 Tro, Chemistry: A Molecular Approach13 alkanes alkenes alkynes

14 Tro, Chemistry: A Molecular Approach14

15 15 Formulas molecular formulas just tell you what kinds of atoms are in the molecule, but they don’t tell you how they are attached structural formulas show you the attachment pattern in the molecule models not only show you the attachment pattern, but give you an idea about the shape of the molecule

16 Tro, Chemistry: A Molecular Approach16 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

17 Tro, Chemistry: A Molecular Approach17 Line-Angle Formulas each angle, and beginning and end represent a C atom H omitted on C included on functional groups multiple bonds indicated double line is double bond, triple line is triple bond

18 Tro, Chemistry: A Molecular Approach18 Formulas

19 Tro, Chemistry: A Molecular Approach19 Formulas

20 Tro, Chemistry: A Molecular Approach20 Isomerism Isomers = different molecules with the same molecular formula Structural Isomers = different pattern of atom attachment Constitutional Isomers Stereoisomers = same atom attachments, different spatial orientation

21 Tro, Chemistry: A Molecular Approach21 Structural Isomers of C 4 H 10 Butane, BP = 0°CIsobutane, BP = -12°C

22 Tro, Chemistry: A Molecular Approach22 Rotation about a bond is not isomerism

23 Tro, Chemistry: A Molecular Approach23 Possible Structural Isomers

24 Tro, Chemistry: A Molecular Approach24 Ex 20.1 – Write the structural formula and carbon skeleton formula for C 6 H 14 start by connecting the carbons in a line determine the C skeleton of the other isomers

25 fill in the H to give each C 4 bonds Ex 20.1 – Write the structural formula and carbon skeleton formula for C 6 H 14

26 convert each to a carbon skeleton formula – each bend and the ends represent C atoms Ex 20.1 – Write the structural formula and carbon skeleton formula for C 6 H 14

27 Tro, Chemistry: A Molecular Approach27 Stereoisomers stereoisomers are different molecules whose atoms are connected in the same order, but have a different spatial direction optical isomers are molecules that are nonsuperimposable mirror images of each other geometric isomers are stereoisomers that are not optical isomers

28 Tro, Chemistry: A Molecular Approach28 Nonsuperimposable Mirror Images mirror image cannot be rotated so all its atoms align with the same atoms of the original molecule

29 Tro, Chemistry: A Molecular Approach29 Chirality any molecule with a nonsuperimposable mirror image is said to be chiral any carbon with 4 different substituents will be a chiral center a pair of nonsuperimposable mirror images are called a pair of enantiomers

30 Tro, Chemistry: A Molecular Approach30 Optical Isomers of 3-methylhexane

31 Tro, Chemistry: A Molecular Approach31 Plane Polarized Light light that has been filtered so that only those waves traveling in a single plane are allowed through

32 Tro, Chemistry: A Molecular Approach32 Optical Activity a pair of enantiomers have all the same physical properties except one – the direction they rotate the plane of plane polarized light each will rotate the plane the same amount, but in opposite directions dextrorotatory = rotate to the right levorotatory = rotate to the left an equimolar mixture of the pair is called a racemic mixture rotations cancel, so no net rotation

33 Tro, Chemistry: A Molecular Approach33 Chemical Behavior of Enantiomers a pair of enantiomers will have the same chemical reactivity in a non-chiral environment but in a chiral environment they may exhibit different behaviors enzyme selection of one enantiomer of a pair

34 Tro, Chemistry: A Molecular Approach34 Alkanes aka 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 chains may be straight or branched saturated branched or unbranched

35 Tro, Chemistry: A Molecular Approach35

36 Tro, Chemistry: A Molecular Approach36 Naming each name consists of 3 parts ü prefix  indicates position, number, and type of branches  indicates position, number, and type of each functional group ü parent  indicates the length of the longest carbon chain or ring ü suffix  indicates the type of hydrocarbon –ane, ene, yne  certain functional groups

37 37 Naming Alkanes 1)Find the longest continuous carbon chain 2)Number the chain from end closest to a branch if first branches equal distance use next in 3)Name branches as alkyl groups locate each branch by preceding its name with the carbon number on the chain 4)List branches alphabetically do not count n-, sec-, t-, count iso 5)Use prefix if more than one of same group present di, tri, tetra, penta, hexa do not count in alphabetizing

38 Tro, Chemistry: A Molecular Approach38 Alkyl Groups

39 Tro, Chemistry: A Molecular Approach39 More Alkyl Groups BUTYL

40 Tro, Chemistry: A Molecular Approach40 Examples of Naming Alkanes 2-methylpentane H H H H H H C C C C C H H CH 3 H H H 3-isopropyl-2,2-dimethylhexane H CH 3 H H H H H C C C C C C H H CH 3 CH H H H CH 3 CH 3

41 Tro, Chemistry: A Molecular Approach41 Example – Name the alkane 1) find the longest continuous C chain and use it to determine the base name since the longest chain has 5 C the base name is pentane

42 Tro, Chemistry: A Molecular Approach42 Example – Name the alkane 2) identify the substituent branches there are 2 substituents both are 1 C chains, called methyl

43 Tro, Chemistry: A Molecular Approach43 Example – Name the alkane 3) number the chain from the end closest to a substituent branch if first substituents equidistant from end, go to next substituent in both substituents are equidistant from the end 1 2 3 4 5 2 4 then assign numbers to each substituent based on the number of the main chain C it’s attached to

44 Tro, Chemistry: A Molecular Approach44 Example – Name the alkane 4) write the name in the following order 1)substituent number of first alphabetical substituent followed by dash 2)substituent name of first alphabetical substituent followed by dash if it’s the last substituent listed, no dash use prefixes to indicate multiple identical substituents 3)repeat for other substituents alphabetically 4)name of main chain 2 4 2,4 – dimethylpentane

45 Tro, Chemistry: A Molecular Approach45 Practice – Name the Following

46 Tro, Chemistry: A Molecular Approach46 Practice – Name the Following 3-ethyl-2-methylpentane

47 Tro, Chemistry: A Molecular Approach47 Drawing Structural Formulas draw and number the base chain carbon skeleton add the carbon skeletons of each substituent on the appropriate main chain C add in required H’s 4-ethyl-2-methylhexane 1 2 3 4 5 6

48 Tro, Chemistry: A Molecular Approach48 Practice – Draw the structural formula of 4- isopropyl-2-methylheptane

49 Tro, Chemistry: A Molecular Approach49 Practice – Draw the structural formula of 4- isopropyl-2-methylheptane

50 Tro, Chemistry: A Molecular Approach50 Alkenes also known as olefins aliphatic, unsaturated C=C double bonds formula for one double bond = C n H 2n subtract 2 H from alkane for each double bond trigonal shape around C flat much more reactive than alkanes polyunsaturated = many double bonds

51 Tro, Chemistry: A Molecular Approach51

52 Tro, Chemistry: A Molecular Approach52 Alkenes ethene = ethylenepropene

53 Tro, Chemistry: A Molecular Approach53 Physical Properties of Alkenes

54 Tro, Chemistry: A Molecular Approach54 Alkynes also known as acetylenes aliphatic, unsaturated C  C triple bond formula for one triple bond = C n H 2n-2 subtract 4 H from alkane for each triple bond linear shape more reactive than alkenes

55 Tro, Chemistry: A Molecular Approach55

56 Tro, Chemistry: A Molecular Approach56 Alkynes ethyne = acetylenepropyne

57 Tro, Chemistry: A Molecular Approach57 Physical Properties of Alkynes

58 Tro, Chemistry: A Molecular Approach58 Naming Alkenes and Alkynes change suffix on main name from -ane to -ene for base name of alkene, or to -yne for the base name of the alkyne number chain from end closest to multiple bond number in front of main name indicates first carbon of multiple bond

59 Tro, Chemistry: A Molecular Approach59 Examples of Naming Alkenes 2-methyl-1-pentene 3-isopropyl-2,2-dimethyl-3-hexene H H H H C C C C C H H CH 3 H H H H CH 3 H H H C C C C C C H H CH 3 CH H H H CH 3 CH 3

60 Tro, Chemistry: A Molecular Approach60 Examples of Naming Alkynes 3-methyl-1-pentyne 4-isopropyl-5,5-dimethyl-2-hexyne H H H H C C C C C H CH 3 H H H CH 3 H H H C C C C C C H H CH 3 CH H CH 3 CH 3

61 Tro, Chemistry: A Molecular Approach61 Name the Alkene 1) find the longest, continuous C chain that contains the double bond and use it to determine the base name since the longest chain with the double bond has 6 C the base name is hexene

62 Tro, Chemistry: A Molecular Approach62 Name the Alkene 2) identify the substituent branches there are 2 substituents one is a 1 C chain, called methyl the other one is a 2 C chain, called ethyl

63 Tro, Chemistry: A Molecular Approach63 Name the Alkene 3) number the chain from the end closest to the double bond then assign numbers to each substituent based on the number of the main chain C it’s attached to 1234 56 4 3

64 Tro, Chemistry: A Molecular Approach64 Name the Alkene 4) write the name in the following order 1)substituent number of first alphabetical substituent – substituent name of first alphabetical substituent – use prefixes to indicate multiple identical substituents 2)repeat for other substituents 3)number of first C in double bond – name of main chain 3–ethyl–4–methyl–2–hexene 1234 56 4 3

65 Tro, Chemistry: A Molecular Approach65 Practice – Name the Following

66 Tro, Chemistry: A Molecular Approach66 Practice – Name the Following 3,4-dimethyl-3-hexene 12 34 56

67 Tro, Chemistry: A Molecular Approach67 Name the Alkyne 1) find the longest, continuous C chain that contains the triple bond and use it to determine the base name since the longest chain with the triple bond has 7 C the base name is heptyne

68 Tro, Chemistry: A Molecular Approach68 Name the Alkyne 2) identify the substituent branches there are 2 substituents one is a 1 C chain, called methyl the other one is called isopropyl

69 Tro, Chemistry: A Molecular Approach69 Name the Alkyne 3) number the chain from the end closest to the triple bond then assign numbers to each substituent based on the number of the main chain C it’s attached to 4 6 1234567

70 Tro, Chemistry: A Molecular Approach70 Name the Alkyne 4) write the name in the following order 1)substituent number of first alphabetical substituent – substituent name of first alphabetical substituent – use prefixes to indicate multiple identical substituents 2)repeat for other substituents 3)number of first C in double bond – name of main chain 4–isopropyl–6–methyl–2–heptyne 4 6 1234567

71 Tro, Chemistry: A Molecular Approach71 Practice – Name the Following

72 Tro, Chemistry: A Molecular Approach72 Practice – Name the Following 3,3-dimethyl-1-pentyne 123 45

73 Tro, Chemistry: A Molecular Approach73 Geometric Isomerism because the rotation around a double bond is highly restricted, you will have different molecules if groups have different spatial orientation about the double bond this is often called cis-trans isomerism when groups on the doubly bonded carbons are cis, they are on the same side when groups on the doubly bonded carbons are trans, they are on opposite sides

74 Tro, Chemistry: A Molecular Approach74 Free Rotation Around C─C

75 Tro, Chemistry: A Molecular Approach75 Cis-Trans Isomerism

76 Tro, Chemistry: A Molecular Approach76 Reactions of Hydrocarbons all hydrocarbons undergo combustion combustion is always exothermic about 90% of U.S. energy generated by combustion 2 CH 3 CH 2 CH 2 CH 3 (g) + 13 O 2 (g) → 8 CO 2 (g) + 10 H 2 O(g) CH 3 CH=CHCH 3 (g) + 6 O 2 (g) → 4 CO 2 (g) + 4 H 2 O(g) 2 CH 3 C  CCH 3 (g) + 11 O 2 (g) → 8 CO 2 (g) + 6 H 2 O(g)

77 Tro, Chemistry: A Molecular Approach77 Other Alkane Reactions Substitution replace H with a halogen atom initiated by addition of energy in the form of heat or ultraviolet light  to start breaking bonds generally get multiple products with multiple substitutions

78 78 Other Alkene and Alkyne Reactions Addition reactions adding a molecule across the multiple bond Hydrogenation = adding H 2 converts unsaturated molecule to saturated alkene or alkyne + H 2 → alkane Halogenation = adding X 2 Hydrohalogenation = adding HX HX is polar when adding a polar reagent to a double or triple bond, the positive part attaches to the carbon with the most H’s

79 Tro, Chemistry: A Molecular Approach79 Addition Reactions

80 Tro, Chemistry: A Molecular Approach80 Aromatic Hydrocarbons contain benzene ring structure even though they are often drawn with C=C, they do not behave like alkenes

81 Tro, Chemistry: A Molecular Approach81 Resonance Hybrid the true structure of benzene is a resonance hybrid of two structures

82 Tro, Chemistry: A Molecular Approach82 Naming Monosubstituted Benzene Derivatives (name of substituent)benzene halogen substituent = change ending to “o” or name of a common derivative fluorobenzene propylbenzene

83 Tro, Chemistry: A Molecular Approach83 Naming Benzene as a Substituent when the benzene ring is not the base name, it is called a phenyl group 4-phenyl-1-hexene

84 Tro, Chemistry: A Molecular Approach84 Naming Disubstituted Benzene Derivatives number the ring starting at attachment for first substituent, then move toward second order substituents alphabetically use “di” if both substituents the same 1 2 3 1-bromo-3-fluorobenzene 1 2 1,2-dimethylbenzene

85 Tro, Chemistry: A Molecular Approach85 Naming Disubstituted Benzene Derivatives alternatively, use relative position prefix ortho- = 1,2; meta- = 1,3; para- = 1,4 2-chlorotoluene ortho-chlorotoluene o-chlorotoluene 3-chlorotoluene meta-chlorotoluene m-chlorotoluene 4-chlorotoluene para-chlorotoluene p-chlorotoluene

86 Tro, Chemistry: A Molecular Approach86 Practice – Name the Following

87 Tro, Chemistry: A Molecular Approach87 Practice – Name the Following 1-chloro-4-fluorobenzene1,3-dibromobenzene or meta-dibromobenzene or m-dibromobenzene

88 Tro, Chemistry: A Molecular Approach88 Polycyclic Aromatic Hydrocarbons contain multiple benzene rings fused together fusing = sharing a common bond

89 Tro, Chemistry: A Molecular Approach89 Reactions of Aromatic Hydrocarbons most commonly, aromatic hydrocarbons undergo substitution reactions – replacing H with another atom or group

90 Tro, Chemistry: A Molecular Approach90 Functional Groups other organic compounds are hydrocarbons in which functional groups have been substituted for hydrogens a functional group is a group of atoms that show a characteristic influence on the properties of the molecule generally, the reactions that a compound will perform are determined by what functional groups it has since the kind of hydrocarbon chain is irrelevant to the reactions, it may be indicated by the general symbol R CH 3 —OH R groupfunctional group

91 91

92 Tro, Chemistry: A Molecular Approach92 Alcohols R-OH ethanol = CH 3 CH 2 OH grain alcohol = fermentation of sugars alcoholic beverages  proof number = 2X percentage of alcohol gasohol isopropyl alcohol = (CH 3 ) 2 CHOH 2-propanol rubbing alcohol poisonous methanol = CH 3 OH wood alcohol = thermolysis of wood paint solvent poisonous

93 Tro, Chemistry: A Molecular Approach93 Naming Alcohols main chain contain OH number main chain from end closest to OH give base name ol ending and place number of C on chain where OH attached in front name as hydroxy group if other higher precedence group present 123456 4-ethyl-4-methyl-3-hex-5-enol

94 Tro, Chemistry: A Molecular Approach94 Reactions of Alcohols Nucleophilic Substitution CH 3 OH + HCl  CH 3 Cl + H 2 O Acid Catalyzed Elimination (Dehydration) CH 3 CH 2 OH  CH 2 CH 2 + H 2 O H 2 SO 4 Oxidation CH 3 CH 2 OH  CH 3 CHO  CH 3 COOH - 2 H with Reactive Metals CH 3 OH + Na  CH 3 O − Na + + ½ H 2

95 Tro, Chemistry: A Molecular Approach95 Aldehydes and Ketones contain the carbonyl group aldehydes = at least 1 side H ketones = both sides R groups many aldehydes and ketones have pleasant tastes and aromas some are pheromones formaldehyde = H 2 C=O pungent gas formalin = a preservative wood smoke, carcinogenic acetone = CH 3 C(=O)CH 3 nail-polish remover formaldehydeacetone

96 96 Aldehyde Odors and Flavors butanal = butter vanillin = vanilla benzaldehyde = almonds cinnamaldehyde = cinnamon

97 97 Ketone Odors and Flavors acetophenone = pistachio carvone = spearmint ionone = raspberries muscone = musk

98 Tro, Chemistry: A Molecular Approach98 Reactions aldehydes and ketones are generally synthesized by the oxidation of alcohols therefore, reduction of an aldehyde or ketone results in an alcohol

99 Tro, Chemistry: A Molecular Approach99 Carbonyl Group C=O group is highly polar many reactions involve addition across C=O, with positive part attached to O

100 Tro, Chemistry: A Molecular Approach100 Addition to C=O

101 Tro, Chemistry: A Molecular Approach101 Carboxylic Acids RCOOH sour tasting weak acids citric acid found in citrus fruit ethanoic acid = acetic acid vinegar methanoic acid = formic acid insect bites and stings

102 Tro, Chemistry: A Molecular Approach102 Carboxylic Acids made by the oxidation of aldehydes and alcohols OH on the end of the chain always on main chain has highest precedence C of group always C1 position not indicated in name change ending to oic acid

103 Tro, Chemistry: A Molecular Approach103 Naming Carboxylic Acids

104 Tro, Chemistry: A Molecular Approach104 Esters R–COO–R sweet odor made by reacting carboxylic acid with an alcohol R a COOH + R b OH  R a COOR b + H 2 O name alkyl group from alcohol, then acid name with oate ending precedence over carbonyls, but not carboxylic acid number from end with ester group aspirin methyl butanoate

105 Tro, Chemistry: A Molecular Approach105 Naming Esters

106 Tro, Chemistry: A Molecular Approach106 Condensation Reactions a condensation reaction is any organic reaction driven by the removal of a small molecule, like water esters are made by the condensation reaction between a carboxylic acid and an alcohol the reaction is acid catalyzed acid anhydrides are made by the condensation reaction between 2 carboxylic acid molecules the reaction is driven by heat

107 Tro, Chemistry: A Molecular Approach107 Synthesis of Aspirin (Acetylsalicylic Acid)

108 Tro, Chemistry: A Molecular Approach108 Ethers R– O – R ether = diethyl ether = CH 3 CH 2 OCH 2 CH 3 anesthetic to name ethers, name each alkyl group attached to the O, then add the word ether to the end diethyl ether

109 Tro, Chemistry: A Molecular Approach109 Amines N containing organic molecules very bad smelling form when proteins decompose organic bases name alkyl groups attached to the N, then add the word amine to the end ethylamineethylmethylamine cadaverine putrescine

110 Tro, Chemistry: A Molecular Approach110 Amines many amines are biologically active dopamine – a neurotransmitter epinephrine – an adrenal hormone pyridoxine – vitamin B 6 alkaloids are plant products that are alkaline and biologically active toxic coniine from hemlock cocaine from coca leaves nicotine from tobacco leaves mescaline from peyote cactus morphine from opium poppies

111 Tro, Chemistry: A Molecular Approach111 Amine Reactions weak bases react with strong acids to form ammonium salts RNH 2 + HCl → RNH 3 + Cl − react with carboxylic acids in a condensation reaction to form amides RCOOH + HNHR’  RCONHR’ + H 2 O

112 Tro, Chemistry: A Molecular Approach112 Macromolecules polymers are very large molecules made by repeated linking together of small molecules monomers natural modified natural polymers synthetic plastics, elastomers (rubber), fabrics, adhesives composites additives such as graphite, glass, metallic flakes

113 Tro, Chemistry: A Molecular Approach113 Natural Polymers polysaccharides cellulose (cotton) starch proteins nucleic acids (DNA) natural latex rubber, etc. shellac amber, lignin, pine rosin asphalt, tar

114 Tro, Chemistry: A Molecular Approach114 Modified Natural Polymers Cellulose Acetate Rayon film Vulcanized Rubber Gun Cotton Celluloid ping-pong balls Gutta Percha fill space for root canal Casein buttons, mouldings, adhesives

115 Tro, Chemistry: A Molecular Approach115 Polymerization the process of linking the monomer units together two processes are addition polymerization and condensation polymerization monomers may link head-to-tail, or head-to-head, or tail-to-tail head-to-tail most common regular pattern gives stronger attractions between chains than random arrangements

116 116 Head-to-Tail Head-to-Head, Tail-to-Tail Cl CCH HH H CC HH H HeadTailHeadTail H CCH HH Cl CC HH H Tail Head

117 Tro, Chemistry: A Molecular Approach117 Addition Polymerization monomers add to the growing chain in such a manner that all the atoms in the original monomer wind up in the chain no other side products formed, no atoms eliminated first monomer must “open” to start reaction done with heat or addition of an initiator chain reaction each added unit ready to add another

118 Addition Polymerization initiator CC H H H Cl CCH HH H CCH HH H + CC H H H CCH HH H CC HH H Cl CCH HH H CC HH H + CC H H H CCH HH H CC HH H CC HH H initiator etc.

119 Tro, Chemistry: A Molecular Approach119 Condensation Polymerization monomer units are joined by removing small molecules from the combining units polyesters, polyamides lose water no initiator needed chain reaction each monomer has two reactive ends, so chain can grow in two directions

120 Tro, Chemistry: A Molecular Approach120 Condensation Polymerization ++ + CC OO HOOH HOCH 2 CH 2 OH HCC OO O OCH 2 CH 2 OH + H 2 O

121 Tro, Chemistry: A Molecular Approach121 Nylon polyamides good physical properties affected by moisture very good heat resistance excellent chemical resistance excellent wear resistance nylon 6,6 made by condensing 1,6–hexandiamine, H 2 N–(CH 2 ) 6 –NH 2, with hexandioic acid, HOOC–(CH 2 ) 4 –COOH (CH 2 ) 6 NHC O (CH 2 ) 4 C O HN

122 Tro, Chemistry: A Molecular Approach122


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