Presentation is loading. Please wait.

Presentation is loading. Please wait.

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

Similar presentations


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 Allotropes of Carbon - Diamond

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

5 Tro, Chemistry: A Molecular Approach5 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

6 Tro, Chemistry: A Molecular Approach6 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

7 7 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 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 liquids, (high boiling) diesel fuel, lubricants, heating oil 50+solids petroleum jelly, paraffin wax

8 Tro, Chemistry: A Molecular Approach8 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

9 Tro, Chemistry: A Molecular Approach9 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

10 Tro, Chemistry: A Molecular Approach10 Unsaturated Hydrocarbons

11 Tro, Chemistry: A Molecular Approach11 Aromatic Hydrocarbons contain benzene ring structure even though they are often drawn with C=C, they do not behave like alkenes

12 Tro, Chemistry: A Molecular Approach12 alkanes alkenes alkynes

13 13 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

14 Tro, Chemistry: A Molecular Approach14 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

15 Tro, Chemistry: A Molecular Approach15 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

16 Tro, Chemistry: A Molecular Approach16 Formulas

17 Tro, Chemistry: A Molecular Approach17 Formulas

18 Tro, Chemistry: A Molecular Approach18 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

19 Tro, Chemistry: A Molecular Approach19 Structural Isomers of C 4 H 10 Butane, BP = 0°CIsobutane, BP = -12°C

20 Tro, Chemistry: A Molecular Approach20 Rotation about a bond is not isomerism

21 Tro, Chemistry: A Molecular Approach21 Possible Structural Isomers

22 Tro, Chemistry: A Molecular Approach22 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

23 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

24 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

25 Tro, Chemistry: A Molecular Approach25 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

26 Tro, Chemistry: A Molecular Approach26 Nonsuperimposable Mirror Images mirror image cannot be rotated so all its atoms align with the same atoms of the original molecule

27 Tro, Chemistry: A Molecular Approach27 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

28 Tro, Chemistry: A Molecular Approach28 Optical Isomers of 3-methylhexane

29 Tro, Chemistry: A Molecular Approach29 Plane Polarized Light light that has been filtered so that only those waves traveling in a single plane are allowed through

30 Tro, Chemistry: A Molecular Approach30 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

31 Tro, Chemistry: A Molecular Approach31 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

32 Tro, Chemistry: A Molecular Approach32 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

33 Tro, Chemistry: A Molecular Approach33

34 Tro, Chemistry: A Molecular Approach34 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

35 35 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

36 Tro, Chemistry: A Molecular Approach36 Alkyl Groups

37 Tro, Chemistry: A Molecular Approach37 More Alkyl Groups BUTYL

38 Tro, Chemistry: A Molecular Approach38 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

39 Tro, Chemistry: A Molecular Approach39 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

40 Tro, Chemistry: A Molecular Approach40 Example – Name the alkane 2) identify the substituent branches there are 2 substituents both are 1 C chains, called methyl

41 Tro, Chemistry: A Molecular Approach41 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 then assign numbers to each substituent based on the number of the main chain C it’s attached to

42 Tro, Chemistry: A Molecular Approach42 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

43 Tro, Chemistry: A Molecular Approach43 Practice – Name the Following

44 Tro, Chemistry: A Molecular Approach44 Practice – Name the Following 3-ethyl-2-methylpentane

45 Tro, Chemistry: A Molecular Approach45 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

46 Tro, Chemistry: A Molecular Approach46 Practice – Draw the structural formula of 4- isopropyl-2-methylheptane

47 Tro, Chemistry: A Molecular Approach47 Practice – Draw the structural formula of 4- isopropyl-2-methylheptane

48 Tro, Chemistry: A Molecular Approach48 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

49 Tro, Chemistry: A Molecular Approach49

50 Tro, Chemistry: A Molecular Approach50 Alkenes ethene = ethylenepropene

51 Tro, Chemistry: A Molecular Approach51 Physical Properties of Alkenes

52 Tro, Chemistry: A Molecular Approach52 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

53 Tro, Chemistry: A Molecular Approach53

54 Tro, Chemistry: A Molecular Approach54 Alkynes ethyne = acetylenepropyne

55 Tro, Chemistry: A Molecular Approach55 Physical Properties of Alkynes

56 Tro, Chemistry: A Molecular Approach56 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

57 Tro, Chemistry: A Molecular Approach57 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

58 Tro, Chemistry: A Molecular Approach58 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

59 Tro, Chemistry: A Molecular Approach59 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

60 Tro, Chemistry: A Molecular Approach60 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

61 Tro, Chemistry: A Molecular Approach61 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

62 Tro, Chemistry: A Molecular Approach62 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

63 Tro, Chemistry: A Molecular Approach63 Practice – Name the Following

64 Tro, Chemistry: A Molecular Approach64 Practice – Name the Following 3,4-dimethyl-3-hexene

65 Tro, Chemistry: A Molecular Approach65 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

66 Tro, Chemistry: A Molecular Approach66 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

67 Tro, Chemistry: A Molecular Approach67 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

68 Tro, Chemistry: A Molecular Approach68 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

69 Tro, Chemistry: A Molecular Approach69 Practice – Name the Following

70 Tro, Chemistry: A Molecular Approach70 Practice – Name the Following 3,3-dimethyl-1-pentyne

71 Tro, Chemistry: A Molecular Approach71 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

72 Tro, Chemistry: A Molecular Approach72 Free Rotation Around C─C

73 Tro, Chemistry: A Molecular Approach73 Cis-Trans Isomerism

74 Tro, Chemistry: A Molecular Approach74 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)

75 Tro, Chemistry: A Molecular Approach75 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

76 76 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

77 Tro, Chemistry: A Molecular Approach77 Addition Reactions

78 Tro, Chemistry: A Molecular Approach78 Aromatic Hydrocarbons contain benzene ring structure even though they are often drawn with C=C, they do not behave like alkenes

79 Tro, Chemistry: A Molecular Approach79 Resonance Hybrid the true structure of benzene is a resonance hybrid of two structures

80 Tro, Chemistry: A Molecular Approach80 Naming Monosubstituted Benzene Derivatives (name of substituent)benzene halogen substituent = change ending to “o” or name of a common derivative fluorobenzene propylbenzene

81 Tro, Chemistry: A Molecular Approach81 Naming Benzene as a Substituent when the benzene ring is not the base name, it is called a phenyl group 4-phenyl-1-hexene

82 Tro, Chemistry: A Molecular Approach82 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 bromo-3-fluorobenzene 1 2 1,2-dimethylbenzene

83 Tro, Chemistry: A Molecular Approach83 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

84 Tro, Chemistry: A Molecular Approach84 Practice – Name the Following

85 Tro, Chemistry: A Molecular Approach85 Practice – Name the Following 1-chloro-4-fluorobenzene1,3-dibromobenzene or meta-dibromobenzene or m-dibromobenzene

86 Tro, Chemistry: A Molecular Approach86 Polycyclic Aromatic Hydrocarbons contain multiple benzene rings fused together fusing = sharing a common bond

87 Tro, Chemistry: A Molecular Approach87 Reactions of Aromatic Hydrocarbons most commonly, aromatic hydrocarbons undergo substitution reactions – replacing H with another atom or group

88 Tro, Chemistry: A Molecular Approach88 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

89 89

90 Tro, Chemistry: A Molecular Approach90 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

91 Tro, Chemistry: A Molecular Approach91 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 ethyl-4-methyl-3-hex-5-enol

92 Tro, Chemistry: A Molecular Approach92 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

93 Tro, Chemistry: A Molecular Approach93 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

94 94 Aldehyde Odors and Flavors butanal = butter vanillin = vanilla benzaldehyde = almonds cinnamaldehyde = cinnamon

95 95 Ketone Odors and Flavors acetophenone = pistachio carvone = spearmint ionone = raspberries muscone = musk

96 Tro, Chemistry: A Molecular Approach96 Reactions aldehydes and ketones are generally synthesized by the oxidation of alcohols therefore, reduction of an aldehyde or ketone results in an alcohol

97 Tro, Chemistry: A Molecular Approach97 Carbonyl Group C=O group is highly polar many reactions involve addition across C=O, with positive part attached to O

98 Tro, Chemistry: A Molecular Approach98 Addition to C=O

99 Tro, Chemistry: A Molecular Approach99 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

100 Tro, Chemistry: A Molecular Approach100 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

101 Tro, Chemistry: A Molecular Approach101 Naming Carboxylic Acids

102 Tro, Chemistry: A Molecular Approach102 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

103 Tro, Chemistry: A Molecular Approach103 Naming Esters

104 Tro, Chemistry: A Molecular Approach104 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

105 Tro, Chemistry: A Molecular Approach105 Synthesis of Aspirin (Acetylsalicylic Acid)

106 Tro, Chemistry: A Molecular Approach106 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

107 Tro, Chemistry: A Molecular Approach107 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

108 Tro, Chemistry: A Molecular Approach108 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

109 Tro, Chemistry: A Molecular Approach109 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


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

Similar presentations


Ads by Google