Presentation on theme: "Chapter 26 “Functional Groups and Organic Reactions”"— Presentation transcript:
1Chapter 26 “Functional Groups and Organic Reactions” Charles Page High SchoolDr. Stephen L. Cotton
2Section 26.1 - Introduction to Functional Groups OBJECTIVES:Define a functional group, and give several examples.
3Section 26.1 - Introduction to Functional Groups OBJECTIVES:Describe halocarbons, and the substitution reactions they undergo.
4Functional Groups Most organic chemistry involves substituents often contain O, N, S, or Palso called “functional groups”- they are the chemically functional part of the molecule, and are the non-hydrocarbon part
5Functional GroupsFunctional group - a specific arrangement of atoms in an organic compound, that is capable of characteristic chemical reactions.What is the best way to classify organic compounds? By their functional groups.
6Functional GroupsThe symbol “R” is used to represent any carbon chains or ringsImportant: Table 26.1, page shows some of the major categories, and their functional groups - KNOW THESE.Table 26.2, p alkyl groups
7Halogen SubstituentsHalocarbons - class of organic compounds containing covalently bonded fluorine, chlorine, bromine, or iodineGeneral formula: R-XNaming? Name parent as normal, add the halogen as a substituent (or prefix) - Examples on page 774
8Halogen SubstituentsThe more highly halogenated the compound is, the higher the b.p. (see Table 26.3, page 775)Few halocarbons found in naturebut, readily prepared and usedhalothane (Fig. 26.3, p.776) and also the hydrofluorocarbons
9Substitution Reactions Organic reactions often much slower than inorganic reactionsmust break strong covalent bondtrying to find new catalysts to useSubstitution - an atom (or group of atoms) replaces another atom or group of atoms
10Substitution Reactions A halogen (shown as “X”) can replace a hydrogen to make a halocarbon:R-H + X2 R-X + HXSunlight is often a sufficient catalyst:CH4 + Cl CH3Cl + HClUV light
11Substitution Reactions Treating benzene with a halogen? Page 776Halogens on carbon chains are readily displaced by hydroxide ions (OH1-) to make an alcohol + a salt:R-X OH1- R-OH X1-CH3-Cl + NaOH CH3-OH + NaCl
13Section 26.2 Alcohols and Ethers OBJECTIVES:Describe the structures and naming of alcohols and ethers.
14Section 26.2 Alcohols and Ethers OBJECTIVES:Define an addition reaction, and give several examples.
15Section 26.2 Alcohols and Ethers OBJECTIVES:Compare the properties of alcohols and ethers.
16Alcohols Alcohols - a class of organic compounds with an -OH group The -OH functional group in alcohols is called a “hydroxyl” group; thus R-OH is the formulaHow is this different from the hydroxide ion? (covalent bonding with the carbon- not ionic with a metal like bases)
17AlcoholsArranged into categories according to the number of R groups attached to the carbon with the hydroxyl1 R group: primary alcohol2 R groups: secondary alcohol3 R groups: tertiary alcoholNote drawings on page 778
18Alcohols Both IUPAC and common names For IUPAC: drop the -e ending of the parent alkane name; add ending of -ol, number the position of -OHparent is the longest chain that contains the carbon with the hydroxyl attached.
19The hydroxyl is given the lowest position number AlcoholsThe hydroxyl is given the lowest position numberAlcohols containing 2, 3, and 4 of the -OH substituents are named diols, triols, and tetrols respectivelyExamples on page 779
20Alcohols Common names: similar to halocarbons, meaning name the alkyl group followed by the word alcoholOne carbon alcohol = methyl alcohol
21AlcoholsMore than one -OH substituents are called glycols (ethylene glycol?)** Examples on page 779 **Phenols - compounds in which a hydroxyl group is attached directly to an aromatic ring. Cresol is the common name of o, m, and p isomers of methylphenol
22Properties of Alcohols Much like water, alcohols are capable of hydrogen bonding between moleculesthis means they will boil at a higher temp. than alkanes and halocarbons with a comparable number of atoms
23Properties of Alcohols Alcohols are derivates of water; the -OH comes from water, and thus are somewhat solubleAlcohols of up to 4 carbons are soluble in all proportions; more than 4 carbons are usually less soluble, because…?
24Properties of Alcohols Many aliphatic alcohols used in laboratories, clinics, and industryIsopropyl alcohol (2-propanol) is rubbing alcohol; used as antiseptic, and a base for perfume, creams, lotions, and other cosmeticsEthylene glycol (1,2-ethanediol) - commonly sold as antifreeze
25Properties of Alcohols Glycerol (1,2,3-propanetriol) - used as a moistening agent in cosmetics, foods, and drugs; also a component of fats and oilsEthyl alcohol (ethanol) used in the intoxicating beverages; an important industrial solvent
26Properties of Alcohols Denatured alcohol- means it has been made poisonous by the addition of other chemicals, often methyl alcohol (methanol, or wood alcohol). As little as 10 mL of methanol has been known to cause permanent blindness, and 30 ml has resulted in death!!!
27Addition Reactions Carbon-carbon single bond is not easy to break In double bonded alkenes, it is easier to break a bondAddition reaction- substance is added at the double or triple bond location, after it is broken
28Addition ReactionsAddition of water to an alkene is a hydration reaction - usually occurs with heat and an acid (such as HCl or H2SO4 acting as a catalyst)Note sample at bottom of page 781 for the formation of ethanol from ethene + water
29Addition ReactionsIf a halogen is added in an addition reaction, the result is a halocarbon that is disubstituted - top page 782The addition of bromine is often used as a test for saturation - p.782Addition of a hydrogen halide? -called monosubstituted halocarbon
30Addition ReactionsAddition of hydrogen to produce an alkane is a hydrogenation reaction, which usually involves a catalyst such as Pt or Pdcommon application is the manufacture of margarine from unsaturated vegetable oils (making them solid from a liquid)
31Addition ReactionsThe hydrogenation of a double bond is a reduction reaction, which in one sense is defined as the gain of HBottom- page 782, ethene is “reduced” to ethane; cyclohexene is “reduced” to cyclohexane
32EthersA class of organic compounds in which oxygen is bonded to 2 carbon groups: R-O-R is formulaNaming? The two R groups are alphabetized, and followed by etherTwo R groups the same? Use the prefix di Examples on page 783
33Ethers Diethyl ether is the one commonly called just “ether” was the first reliable general anestheticdangerous- highly flammable, also causes nauseaethers are fairly soluble in waterNote the LINK on page 784
34Section 26.3 Carbonyl Compounds OBJECTIVES:Distinguish among the carbonyl groups of aldehydes, ketones, carboxylic acids, and esters.
35Section 26.3 Carbonyl Compounds OBJECTIVES:Describe the reactions of compounds that contain the carbonyl functional group.
36Aldehydes and Ketones Review: alcohol has an oxygen bonded to a carbon group and a hydrogenether has an oxygen bonded to two carbon groupsAn oxygen can also be bonded to a single carbon by a double bond
37Aldehydes and Ketones The C=O group is called the “carbonyl group” it is the functional group in both aldehydes and ketonesAldehydes - carbonyl group always joined to at least one hydrogen (meaning it is always on the end!)
38Aldehydes and KetonesKetones - the carbon of the carbonyl group is joined to two other carbons (meaning it is never on the end)Structures - middle of page 785
39Aldehydes and Ketones Naming? Aldehydes: identify longest chain containing the carbonyl group, then the -e ending replaced by -al, such as methanal, ethanal, etc.Ketones: longest chain w/carbonyl, then new ending of -one; number itpropanone, 2-pentanone, 3-pentanone
40Aldehydes and Ketones Table 26.4, page 786 examples Neither can form intermolecular hydrogen bonds, thus a much lower b.p. than corresponding alcoholswide variety have been isolated from plants and animals; possible fragrant odor or taste; many common names
41Aldehydes and Ketones Benzaldehyde Cinnamaldehyde Vanillin Methanal (common: formaldehyde)40% in water is formalin, a preservative
42Aldehydes and KetonesPropanone (common: acetone) is a good solvent; miscible with water in all proportionswhy is it a good substance used in nail-polish removers? (a powerful solvent-able to dissolve both polar & nonpolar)
43Carboxylic AcidsAlso have a carbonyl group (C=O), but is also attached to a hydroxyl group (-OH) = “carboxyl” groupgeneral formula: R-COOHweak acids (ionize slightly)Named by replacing -e with -oic and followed by the word acidmethanoic acid; ethanoic acid
44Carboxylic AcidsAbundant and widely distributed in nature, many having a Greek or Latin word describing their originacetic acid (ethanoic acid) from acetum, meaning vinegarmany that were isolated from fats are called fatty acidsTable 26.6 page 789
45Esters General formula: RCOOR Derivatives of the carboxylic acids, in which the -OH from the carboxyl group is replaced by an -OR from an alcohol:carboxylic acid + alcohol ester + watermany esters have pleasant, fruity odors- banana, pineapple, perfumes
46EstersAlthough polar, they do not form hydrogen bonds (reason: there is no hydrogen bonded to a highly electronegative atom!)thus, much lower b.p. than the hydrogen-bonded carboxylic acids they came from
47EstersCan be prepared from a carboxylic acid and an alcohol; usually a trace of mineral acid added as catalyst (because acids are dehydrating agents)Note equation on bottom p. 790
48Esters Naming? It has 2 words: 1st: alkyl attached to single bonded oxygen from alcohol2nd: take the acid name, remove the -ic acid, add -ateexample on top of page 791
49Oxidation- Reduction Reactions All of the previous classes of organic compounds are related by oxidation and reduction reactionsWhat is oxidation-reduction?Oxidation: the gain of oxygen, loss of hydrogen, or loss of e-1Reduction: the loss of oxygen, gain of hydrogen, or gain of e-1
50Oxidation- Reduction Reactions Oxidation and reduction reactions (sometimes called redox) are coupled- one does not occur without the otherThe number of Oxygen and Hydrogen attached to Carbon indicates the degree of oxidation
51Oxidation- Reduction Reactions The fewer the # of H on a C-C bond, the more oxidized the bondThus, a triple bond is more oxidized than a double bond and a single bondAn alkane is oxidized (loss of H) to an alkene, and then to an alkyne
52Oxidation- Reduction Reactions Loss of hydrogen is called a dehydrogenation reactionmay require strong heating and a catalystNote equations on page 791
53Oxidation- Reduction Reactions Methane can be oxidized in steps to carbon dioxide (top page 792):methane methanol methanal methanoic acid CO2the more reduced (more H) a carbon compound, the more energy it can release upon oxidation
54Oxidation- Reduction Reactions Alcohols can also be oxidized into other products“Dr. Al K. Hall Mr. Al D. Hyde”Equations top of page 793Preparing aldehydes from a primaryf alcohol is a problem, because they are then easily oxidized to carboxylic acids
55Oxidation- Reduction Reactions Benedict’s test and Fehling’s test are commonly used for aldehyde detection - margin p. 793
56Section 26.4 Polymerization OBJECTIVES:Define polymer and monomer.
57Section 26.4 Polymerization OBJECTIVES:Name and describe the uses of some important addition and condensation polymers.
58Addition PolymersPolymers are giant molecules, not small like the ones studied earlier in this chapterexamples are plasticsPolymer- large molecule formed by the covalent bonding of smaller molecules called monomers
60Addition PolymersAn addition polymer forms when unsaturated monomers react to form a polymerethene will form polyethylene, shown on page 795polyethylene is easy to clean, chemically resistant- milk bottles, plastic wrap, refrigerator dishes
62Addition PolymersPolypropylene is a stiffer polymer, used in utensils and containersPolystyrene is formed from styrene (phenylethene), and is a poor heat conductor (styrofoam – Dow Chemical)molded coffee cups and picnic coolers, insulates homesPolyvinyl chloride (PVC) used for pipes in plumbing
63Addition PolymersPolytetrafluoroethene (PTFE, or “Teflon”) is very resistant to heat and chemical corrosionfound on nonstick cookware; coating on bearings and bushings used in chemical reactors
64Condensation Polymers Condensation polymers are formed by the head-to-tail joining of monomer unitsusually accompanied by the loss of water from the reacting monomers, and forming water as a product
65Condensation Polymers Ex: polyethylene terephthalate (PETE)Dacron, Fortrel, Polyesters: permanent press clothing, tire cordsSheets of polyester called Mylar, used as magnetic tape in tape recorders and computers, as well as balloonsNylon: carpet, fishing line, hosiery
66Condensation Polymers Examples:aromatic rings form Nomex, which is a poor electrical conductor; makes parts for electrical fixtures; flame resistant clothing for race car drivers; flame resistant building materialsKevlar: strong and flame resistant
67Plastic container code system. MATERIALPERCENT OF TOTALPolyethylene Terephthalate (PETE)20-30 percentHigh Density Polyethylene50-60 percentPolyvinyl Chloride (PVC)5-10 percentLow Density PolyethylenePolypropylenePolystyreneAll other resins
68What Do the Numbers Mean? 1 -- PETE (Polyethylene terephthalate)PET is used in the production of soft drink bottles, peanut butter jars...PET can be recycled into fiberfill for sleeping bags, carpet fibers, rope, pillows...
69What Do the Numbers Mean? 2 -- HDPE (High-density polyethylene)HDPE is found in milk jugs, butter tubs, detergent bottles, motor oil bottles...HDPE can be recycled into flower pots, trash cans, traffic barrier cones, detergent bottles...
70What Do the Numbers Mean? 3 -- V (Polyvinyl chloride)PVC is used in shampoo bottles, cooking oil bottles, fast food service items...PVC can be recycled into drainage and irrigation pipes...
71What Do the Numbers Mean? 4 -- LDPE (Low-density polyethylene)LDPE is found in grocery bags, bread bags, shrink wrap, margarine tub tops...LDPE can be recycled into new grocery bags...
72What Do the Numbers Mean? 5 -- PP (Polypropylene)PP is used in most yogurt containers, straws, pancake syrup bottles, bottle caps....PP can be recycled into plastic lumber, car battery cases, manhole steps...
73What Do the Numbers Mean? 6 -- PS (Polystyrene)PS is found in disposable hot cups, packaging materials (peanuts), and meat trays...PS can be recycled into plastic lumber, cassette tape boxes, flower pots...
74What Do the Numbers Mean? 7 -- OtherThis is usually a mixture of various plastics, like squeeze ketchup bottles, "microwaveable" dishes...
75Timeline of Plastics 1862 – First man-made plastic 1866 – Celluloid makes it’s debut1891 – Rayon is discovered1907 – Bakelite is invented1913 – Cellophane causes the plastics craze
76Timeline of Plastics 1926 – PVC is invented 1933 – Polyethylene is discovered1933 – Saran makes it’s debut1938 – Teflon is discovered1939 – Nylon stockings hit market1957 – Here comes velcro