Functional Groups

1
Functional Groups
2
Functional Groups

• Functional group - a specific arrangement of
  atoms in an organic compound, that is capable of
  characteristic chemical reactions.
• The symbol R is used to represent any carbon
  chains or rings (i.e. the REST of the compound)

3
Functional Groups

• Most organic chemistry involves substituents
• often contain O, N, S, or P
• also called functional groups- they are the
  chemically functional part of the molecule, and
  are the non-hydrocarbon part

4
Halogen Substituents

• Halocarbons - class of organic compounds
  containing covalently bonded fluorine, chlorine,
  bromine, or iodine
• General formula R-X (X halogen)
• CH3-I Iodomethane
• CH3CH2Br Bromoethane

5
Alcohols

• 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 formula
• How is this different from the hydroxide ion?
  (covalent bonding with the carbon- not ionic with
  a metal like bases)

6
Alcohols

• Naming
• drop the -e ending of the parent alkane name add
  ending of -ol, number the position of OH
• The one carbon alcohol, CH3-OH is called methyl
  alcohol or methanol

7
Alcohols
8
Alcohols

• Phenols - compounds in which a hydroxyl group is
  attached directly to an aromatic ring (benzene).

9
Properties of Alcohols

• Much like water, alcohols are capable of hydrogen
  bonding between molecules
• they will boil at a higher temp. than alkanes and
  halocarbons with a comparable number of atoms

10
Properties of Alcohols

• Alcohols are derivates of water the -OH comes
  from water, and are somewhat soluble
• the longer carbon chain the more non-polar the
  molecule which makes it less soluble in water.

11
Properties of Alcohols

• Many aliphatic alcohols used in laboratories,
  clinics, and industry
• Isopropyl alcohol (2-propanol) is rubbing
  alcohol used as antiseptic, and a base for
  perfume, creams, lotions, and other cosmetics
• Ethylene glycol (1,2-ethanediol) - commonly sold
  as antifreeze

12
Properties of Alcohols

• Glycerol (1,2,3-propanetriol) - used as a
  moistening agent in cosmetics, foods, and drugs
  also a component of fats and oils
• Ethyl alcohol (ethanol) CH3CH2OH used in the
  intoxicating beverages also an important
  industrial solvent

13
Properties of Alcohols

• Denatured alcohol- means it has been made
  poisonous by the addition of other chemicals,
  often methyl alcohol (methanol, or wood alcohol).
  We use denatured alcohol in lab!!!!
• As little as 10 mL of methanol has been known to
  cause permanent blindness, and 30 ml has
  resulted in death!

14
Ethers

• An ether is a class of organic compounds in which
  oxygen is bonded to 2 carbon groups
• R-O-R is formula
• Naming? The two R groups are alphabetized, and
  followed by ether

15
Ethers

• Diethyl ether is the one commonly called just
  ether
• was the first reliable general anesthetic
• dangerous- highly flammable, also causes nausea
• ethers are fairly soluble in water

16
Aldehydes and Ketones

• An oxygen can also be bonded to a single carbon
  by a double bond
• The CO group is called the carbonyl group
• it is the functional group in both aldehydes and
  ketones

17
Aldehydes and Ketones

• Aldehydes - carbonyl group always joined to at
  least one hydrogen (meaning it is always on the
  end!)
• -e ending replaced by -al, such as methanal,
  ethanal

18
Aldehydes and Ketones

• Ketones - the carbon of the carbonyl group is
  joined to two other carbons (meaning it is never
  on the end)
• ending of one such as propanone, 2-pentanone,
  3-pentanone

19
Aldehydes and Ketones

• Neither can form intermolecular hydrogen bonds,
  thus a much lower b.p. than corresponding
  alcohols
• wide variety have been isolated from plants and
  animals possible fragrant odor or taste many
  common names

20
Aldehydes and Ketones

• Benzaldehyde
• Cinnamaldehyde
• Vanillin
• Methanal (the common name is formaldehyde)
• 40 in water is formalin, a preservative

21
Aldehydes and Ketones

• Propanone (common acetone) is a good solvent
  miscible with water in all proportions
• why is it a good substance used in nail-polish
  removers? (a powerful solvent-able to dissolve
  both polar nonpolar)

22
The Carboxylic Acids

• A Carboxyl group has a carbonyl group (CO)
  attached to a hydroxyl group (-OH) formula
  R-COOH
• weak acids (ionize
  slightly)
• Named by replacing -e with -oic and followed by
  the word acid
• methanoic acid ethanoic acid

23
Carboxylic Acids

• Abundant and widely distributed in nature, many
  having a Greek or Latin word describing their
  origin
• acetic acid (ethanoic acid) from acetum, meaning
  vinegar
• Many isolated from fats are called fatty acids

24
The Esters

• Esters formula RCOOR
• Condensation reaction
• carboxylic acid alcohol ? ester water
• usually a trace of mineral acid added as catalyst
  (because acids are dehydrating agents)
• many esters have pleasant, fruity odors- banana,
  pineapple, perfumes

25
Esters

• Although polar, they do not form hydrogen bonds
  thus, much lower b.p. than the hydrogen-bonded
  carboxylic acids they came from

26
Esters

• Naming? It has 2 words
• remove the -ic acid, add -ate

27
Functional Group Review
28
Polymers

• Polymers are giant molecules, not small like the
  ones studied earlier in this chapter
• examples are plastics
• Polymer- large molecule formed by the covalent
  bonding of smaller molecules called monomers

29
Polymers from Monomers
30
Addition Polymers

• An addition polymer forms when unsaturated
  monomers react to form a polymer
• ethene will form polyethylene
• polyethylene is easy to clean, chemically
  resistant- milk bottles, plastic wrap,
  refrigerator dishes

31
High Density Polyethylene
32
Addition Polymers

• Polypropylene is a stiffer polymer, used in
  utensils and containers
• Polystyrene is formed from styrene
  (phenylethene), and is a poor heat conductor
  (styrofoam Dow Chemical)
• molded coffee cups and picnic coolers, insulates
  homes
• Polyvinyl chloride (PVC) used for pipes in
  plumbing

33
Addition Polymers

• Polytetrafluoroethene (PTFE, or teflon DuPont)
  is very resistant to heat and chemical corrosion
• found on nonstick cookware coating on bearings
  and bushings used in chemical reactors

34
Condensation Polymers

• Condensation polymers are formed by the
  head-to-tail joining of monomer units
• usually accompanied by the loss of water from the
  reacting monomers, and forming water as a product

35
Condensation Polymers

• Ex polyethylene terephthalate (PET)
• Dacron ( DuPont), Fortrel ( Wellman),
  Polyesters permanent press clothing, tire cords
• Sheets of polyester called Mylar ( DuPont), used
  as magnetic tape in tape recorders and computers,
  as well as balloons
• Nylon carpet, fishing line, hosiery

36
Condensation Polymers

• Examples
• aromatic rings form Nomex ( DuPont), which is a
  poor electrical conductor makes parts for
  electrical fixtures flame resistant clothing for
  race car drivers flame resistant building
  materials
• Kevlar ( DuPont) strong and flame resistant

37
Plastic container code system.
38
What Do the Numbers Mean?

• 1 -- PETE (Polyethylene terephthalate)
• PET (or PETE) 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...

39
What 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...
  

40
What 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...

41
What 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...

42
What 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...

43
What 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...

44
What Do the Numbers Mean?

• 7 -- Other
• This is usually a mixture of various plastics,
  like squeeze ketchup bottles, "microwaveable"
  dishes...

45
Timeline of Plastics
1862 First man-made plastic 1866 Celluloid
makes its debut 1891 Rayon is discovered 1907
Bakelite is invented 1913 Cellophane causes
the plastics craze
46
Timeline of Plastics
1926 PVC is invented 1933 Polyethylene is
discovered 1933 Saran makes its debut 1938
Teflon is discovered 1939 Nylon stockings hit
market 1957 Here comes velcro