CH. 9 & 10 CHEMISTRY STUDY GUIDE EXAM 3
CH305 Exam 3 Things to know: Chapter 9&10 only. A few ideas from the last exam may carry through, and some
concepts from CH304K of course. Again, this might not cover absolutely everything, but it gives you a good starting
point.
Know all the functional groups given in Ch 9 AND in Ch.10. Be able to spot them in a structure.
Chapter 9: The World of Polymers and Plastics
-POLYMERS are everywhere! are NATURAL and SYNTHETIC are made from non-renewable and (now
sometimes) renewable materials
-Most polymers (CDs, DVDs, plastic case around cell phone/pencil, calculator, computer) come
from a single raw material: petroleum (main feedstock for polymers)
- Petroleum: non-renewable resource 3% of petroleum is used as a raw material (some of this is
for pharmaceuticals)
-“Big Six” all made from petroleum
-Polymers can be made from any carbon-containing starting material (crude oil)
-Renewable resources to form polymers: materials such as wood, cotton fibers, straw, starch
and sugar
-Cargill Dow: “Nature Work PLA” from corn glucose
-DuPont: “Sonora”-family of polymers from corn based substances
Polymers: large molecules containing a long chain or chains of atoms covalently bonded
together; can contain 1000s of atoms
-referred to as macromolecules: molecules of high molecular mass that have characteristic
properties b/c of their large size
-Monomers: (mono- “one” meros- “unit”) small molecules used to synthesize the larger
polymeric chain
-polymers can be formed from the same type of monomer or from a combination
What is a Plastic?: “capable of being molded” (used as a noun or adjective)
PLASTICS are SYNTHETIC polymers. Other materials may have plastic properties (metals).
NOT ALL POLYMERS are PLASTICS! Some polymers occur naturally.
Adding Up the Monomers:
-Covalent chemical bonds connect the monomers
-polymer contains exactly the same number and kinds of atoms as did the monomers
-Addition polymerization: the monomers add to the growing polymer chain in such a way that
the product contains all the atoms of the starting material. No other products are formed
Polyethylene: found in plastic milk jugs, detergent containers, baggies, and packaging materials;
has wide variety of uses but all are made from the same starting material : H2C = CH2
-Dispersion forces: the intermolecular attractive forces holding polyethylene together; attractions between molecules that result from a distortion of the electron cloud that causes an
uneven distribution of the negative charge
-A strategy to control the molecular structure and physical properties of polymers is to regulate
the branching of the polymer chain ; used to produce high-density polyethylene (HDPE) and
low-density polyethylene (LDPE)
-LDPE: stretchy, transparent, not very strong; central polymer chain has many side branches
-HDPE: linear (unbranched) polyethylene chains consisting of 10,000 monomer units; long
chains can arrange more parallel w/o the branching; more crystalline than the irregular tangle of
the polymer chains in LDPE; GREATER DENSITY, RIGIDITY, STRENGTH, and a HIGHER
MELTING POINT than LDPE; OPAQUE
SEE WRITTEN NOTES ON POLYETHYLENE & THE BIG SIX!!
“The Big Six”: over 60,000 synthetic polymers are known; 6 synthetic polymers account for 75%
of those used in the U.S.; “THE BIG SIX”
1. Polyethylene (LDPE)
-soft, flexible, unreactive
-plastic bags, bubble wrap, electrical insulation, ‘dispenser’ type bottles
2. Polyethylene (HDPE)
-stiffer than LDPE
-stiff plastic bags, milk jugs
3. Polypropylene (PP)
-rigid, strong, shiny, impermeable
-battery cases, carpets, bottle caps
4. Polystyrene (PS)
-very clear, rigid, dissolves in many solvents
-Styrofoam insulation..AND drinking glasses
5. Polyvinyl chloride (PVC)
-rigid, strong, resists solvents and oils: used for pipe, siding, credit cards
-PLASTICIZER added to make it flexible for hose, shower curtains
6. Polyethylene terephthalate (PET)
-TWO different monomers
-transparent, strong, impervious to gases
-soda bottles, clear food containers, fleece fabrics, carpet yarns, beverage glasses
-Don’t all use different monomers! ; ALL are COLORLESS; all are INSOLUABLE in WATER,
however so dissolve/soften in the presence of hydrocarbons, fats, and oils
THERMAL PROPERTIES
-All 6 polymers are thermoplastic: with heat they can be melted and reshaped over and over
again VS. thermosetting: CANNOT be re-melted and shaped
PHYSICAL PROPERTIES
Some parts of the same polymer have varying degrees of toughness and strength
-crystalline regions: the long polymer molecules are arranged neatly and tightly in a regular
pattern; very orderly and repeating pattern; make polymers rigid and strong
-dominant in HDPE, PP
- plasticizers: disrupt crystallinity, making a polymer more flexible
-amorphous regions: the long polymer molecules are found in a random, disordered
arrangement and their packing is much looser; make polymers flexible
-dominant in PET, PS, PVC
ADDITION POLYMERS: Polyethylene (HDPE, LDPE), Polyvinyl chloride (PVC),
Polypropylene (PP), Polystyrene (PS)
CONDENSING THE MONOMERS
Functional groups: common groups of atoms different monomers contain; distinctive
arrangements of groups of atoms that impart characteristic chemical properties to the molecules
that contain them
-Hydroxyl
-carboxylic acid
-ester
-amine
-amide
-phenyl
condensation polymerization: process in which the monomers join by eliminating (splitting out)
a small molecule such as water
-TWO PRODUCTS: the polymer itself & molecules released during the polymer’s
formation
-AMINO ACIDS/PROTEINS, NYLON, PET/PETE
copolymer: a combination of two of more different monomers
-POLYETHYLENE TEREPHTHALATE (PET) : made of ethylene glycol & terephthalic
acid
-POLYAMIDES: NATURAL AND NYLON
-Two other classes of polymers
1. Proteins (natural polymers)
2. Nylon (synthetic substitute)
amino acids: the monomers from which our body builds proteins; each amino acid molecule
contains two functional groups: an amine group (-NH2) and a carboxylic acid group (-COOH)
-20 different amino acids occur naturally
polyamides: PROTEINS/NYLON are polyamides: condensation polymers that contain the amide
functional group
peptide bond: the covalent bond that forms when the –COOH group of one amino acid reacts
with the –NH2 group of another, thus joined the two amino acids.
RECYLCING: THE BIG PICTURE
Municipal solid water (MSW): includes everything you discard or throw into your trash
including food scraps, grass clippings, and old appliances. MSW does not include industrial waste
or waste from construction sites.
Disposal of Plastics : Most of our plastic ends up in a landfill! Alternatives: Incineration
Biodegradation Reuse Recycle Reduction
Incineration of Plastics Your Turn 9.22 Per pound contains more energy than coal! Does generate CO2
and may also generate HCl, phosgene (COCl2) and leave ash with heavy metals Resulting ash
however is a MUCH smaller volume - and metals can be extracted from it, if profitable.
Biodegradation
Consider This 9.19, 9.21 Big Six not broken down by bacteria. Biodegradable versions
being developed but questions continue about how well they degrade and the toxity of the degradation
products. These 'compostable plastics' (see Fig 9.15) must be composted done under the right conditions.
EVEN NATURALLY OCCURRING polymers do NOT break down in landfills! See Fig 9.16. This is due
to the anaerobic (oxygen-free) conditions that exist in landfills. “Paper vs Plastic” (Consider This 9.26)
Volume is the biggest problem: 11% of landfill trash is plastic, 35%, paper. (by mass: see Fig 9.14) Plastic
bags take up less room than paper! (See Fig 9.21 page 417)
RECYCLING PLASTICS: THE DETAILS
Recycling Plastics ALL of the Big Six, can be recycled...........................in theory BUT: Unlike
aluminium, more energy is used than in synthesizing new! The idea is to reduce the dependency on fossil
fuels. See Fig 9.17, 9.18, 9.19 and Table 9.3: The US is recycling more of everything now than in the past..
but the overall percent of plastics recycled in the US is DROPPING!! We recycle more each year... but
EVEN more is being manufactured!
Bottle bills are a way to encourage compliance.. but are hotly
debated.
Why Recycling Plastic is not always done: Must be a good alternative to virgin plastic: Consistent
availability requires reliable collection facilities. Consistent purity requires thoroughly sorting AND
cleaning . Price of crude oil also affects demand.. cheap crude means cheaper virgin plastic. Often ends up
as flowerpots or plastic lumber – downgraded. (Consider This 9.28, 9.29)
Recycling “Success”:
PET (1) bottles can become polyester fabrics: fleece, carpeting, tops of running shoes LPDE (4) grocery
bags – return to store, becomes more bags
Reduce, Reuse, Recycle: RECYCLED - CONTENT: has recycled materials IN it. Two kinds:
PRECONSUMER CONTENT: Recycled materials are from manufacturing process (scraps, trimmings i.e., 'cleaner' - easier for the manufacturer to do) POSTCONSUMER CONTENT: Recycled materials are
those which would have ended up in the trash - industrial or consumer - this is the best one!!
"RECYCLABLE" DOES NOT MEAN THE SAME THING as the above statements!!! Look for “%
post consumer waste” on label.
Consumers must create demand for products made with it!!!
Alternative Plastics Recycling DuPont has developed a process to break PET back into monomers!!
Reuse / Reduce Examples: Styrofoam Peanuts: donate to smaller shipping stores (call first and ask!) Many
bottles / food containers are now made with less plastic - look for these. Avoid excessively packaged
products.
Which two of the BIG SIX are the same monomer? Polyethylene (LDPE) & Polyethylene (HDPE)
Chapter 10:MANIPULATING MOLECULES & DESIGNING DRUGS
-Prescription Drugs, Over the Counter (OTC) Drugs, Herbal Alternatives, Illicit Drugs and Abused
Prescription Drugs
-Early Drugs; Folk remedies, Discovered by trial and error, Passed on by word of mouth (China, India,
Egypt, Rome/Greece)
-Willow Bark Tea (ASPIRIN): Folk remedy - known in several cultures Reduced fevers
(ANTIPYRETIC), inflammation (ANTI-INFLAMMATORY) and pain: (ANALGESIC)
- 4th century B.C. : Hippocrates documents “willow bark tea”
- 1763: Edmund Stone (England) investigates willow tree bark (Salix alba) - reports to Royal Society.
Active ingredient isolated from willow bark tea: - two compounds were found, only one was
effective.
o The active one which became an acid in the body was named salicin. Salicin was
synthesized and used.. with SIDE EFFECTS! It tastes terrible, and can cause stomach
irritation.
-Felix Hoffman's father took salicin for his arthritis - got nauseous. In 1898 (while a chemist at Bayer),
Hoffman modified salicin:
-reacted the alcohol part with acetic acid: made an ESTER.
-The salicin still had another acid group: so the end result was called acetylsalicylic acid : or
ASPIRIN ESTER part: lessened effect of the remaining acid group so: tasted better; irritated
stomach less BUT.. in body, this splits back into salicin and acetic acid - works just as well as salicin!
STILL has side effects: (drowsiness, rash/hives/itch, nausea/vomiting/abdominal pain, heartburn,
black/bloody vomit, jaundice, shortness of breath)
-chemical name: 2-(acetyloxy)-benzoic acid or acetylsalicylic acid
-World’s most widely used drug
- analgesic: anti-pain medications
- anti-inflammatory
- antipyretic: fever-reducing
Organic Chemistry: devoted to the study of carbon compounds
-when bonded, each carbon atom has a share in 8 electrons, an octet :OCTET RULE
Carbon: 4 bonds
Nitrogen: 3 bonds
Oxygen: 2 bonds
Hydrogen: 1 bond
Chemical formulas: (C4H10); indicated the kinds and numbers of atoms present in a molecule;
do not show how the atoms are arranged or connected
Structural formulas: used to show the atoms and their arrangement with respect to one another
in a molecule ex. n-butane C4H10
HHHH
H-C-C-C-C-H
HHHH
Condensed Structural Formulas: where carbon-to-hydrogen bonds are not drawn our explicitly,
but simply understood to be single bonds
Ex. for n-butane
CH3-CH2-CH2-CH3 or CH3CH2CH2CH3
Isomers: are molecules with the same chemical formula (same number and kinds of atoms), but
with different structures and properties
Structural Isomers: Different ways of arranging the same number of atoms
Different chemical and physical properties
The more C’s in the molecule the more isomers!
Example: Recall Chapter 4: There are only TWO isomers for butane, but more for octane. Just two are:
HHHHHHHH
HCC C C C C C CH
HH HH H HH H
n-octane (BP 125oC )
H CH3 H CH3 H
HC C C C C H
H CH3 H H H
Isooctane
(BP 99oC)
Line-angle drawing: a simplified version of a structural formula that is most useful for
representing larger molecules
TABLE 10.2 from the Book:
FUNCTIONAL GROUPS
-distinctive arrangements of groups of atoms that impart characteristic physical and
chemical properties to the molecules that contain them.
SEE SEPARATE WRITTEN NOTES OF FUNCTIONAL GROUPS/ DIAGRAMS (TABLE 10.3)
-you should recognize functional groups and know ones are polar (Water, Methanol, Acetic acid),
and know the presence of polar functional groups (-OH , -COOH) encourages the drug to be more
water soluble, the more polar the molecules, the more water soluble it will be, etc.
Organic Prefixes Used for a length of carbon atoms in a chain:
Meth- one
Hexsix
Ethtwo
Hept- seven
Prop- three
Octeight
Butfour
nonnine
Pent- five
decten
Naming Practice: SEE 10.3 TABLE:
Dipropyl ether
Ethyl methanoate
Butylamine
Methanal
Methyl ethyl ketone
Returning to ASPIRIN:
We can now show how it is made:
ESTER FORMATION REACTION:
Salicin
Reacts with Ethanoic (Acetic) Acid gives Acetylsalicylic acid: “ASPIRIN” and water
Solubility of Organic Molecules
Functional groups like: alcohol, carboxylic acid, amine add polar bonds to an organic compound
-- make the molecule more polar - more likely to be water soluble
Molecules without polar groups or mostly just C,H tend to be NON polar.
-- tend to NOT be soluble in water -- tend to dissolve in oils or fats:cell membranes, fatty tissue
Increasing Solubility of Organic Molecules
Convert the molecule into a SALT: Increases stability, water solubility, less odor
Acid + BaseSalt + Water
Nitrogen in an amine or amide can accept a proton from water or acid – make a +ve ion.
Remember ammonia? These look similar.
‘Freebase”: the drug before it accepts the H from acid .
Example: pseudophedrine:
Now make it into a salt: Add HCl
Salt: Pseudophedrine Hydrochloride salt.
Back to Aspirin: Side effects significant! Need alternatives: molecules with similar shapes have similar
physiological effects. Most common: (see Fig 10.7) Ibprofen (Advil), Acetominophen (Tylenol)
Molecular Structure and Drug Activity
Messages in body between cells relayed by: electrical impulses and chemical processes (more common)
Hormones: the chemical messengers produced by the body’s endocrine glands
HORMONES: Chemical messengers. (Fig 10.8)
Produced by ENDOCHRINE GLANDS. Received by receptor sites on the target cell. EXAMPLES:
Hormone
Thyroxine
Insulin
Adrenaline
Steroids
Gland
thyroid
pancreas
adrenal
various
Effect
regulate metabolism
using glucose for energy
fight/flight
various
Prostaglandins: Hormone-like molecules made by cyclooxygenase (COX) enzymes*.
COX-2: makes prostaglandins which cause fever & swelling, increase sensitivity of pain receptors, prevent
blood vessels dilating
COX-1: make prostaglandins that regulate kidney and stomach function (acid, mucus production)
ENZYME* = PROTEIN THAT ACTS AS A BIOLOGICAL CATALYST
Encourages a reaction to go faster OR Encourages one product / set of products to form vs. different ones.
How Aspirin Works
Blocks COX enzymes: reduces fever & swelling, suppresses pain receptors
Aspirin's benzene ring makes it also fat-soluble: absorbed into cell membranes and partly taken into
"specialized cells". These cells blocks transmission of signals triggering inflammation.
This cell uptake is also thought to factor into aspirin's function as a pain reliever.
NSAIDS: Non Steroidal Anti Inflammatory Drugs. Includes aspirin, ibuprofen, acetaminophen
Compare the three:
Aspirin: blocks COX enzymes: partly taken into specialized cells.
Acetominophen: blocks COX enzymes NOT taken into specialized cells.
Ibuprofen: blocks COX enzymes better than aspirin: taken into specialized cells more than aspirin.
SO:
Aspirin: pain & fever reduction, good antiinflammatory.
Acetominophen: pain & fever reduction, poor antiinflammatory.
Ibuprofen: better* pain & fever reduction, better* antiinflammatory.
*than aspirin
Other Uses of Aspirin prevents blood clotting – uniquely. Regular doses prevent heart attacks / stroke ....
but this is why you don’t want to use it post surgery or if you have ulcers!
Why not just block COX-2?
1992: COX-2’s structure found
New “superaspirins” created, e.g.:Vioxx and Celebrex Should be safer! and more effective. They aren’t!
Vioxx has been withdrawn (inc. risk heart attack and stroke)
Dr. Idiotbox: Aggressive ads by makers of Vioxx and Celebrex netted huge sales:
$2.5 billion Vioxx $2.9 billion Celebrex.
Who should decide which drug is best to use?
Buyer Beware: Not all aspirins are equal. Generic drugs required to have same active ingredient
but Active ingredient usually small % of the tablet!
e.g. buffered aspirin: contains weak base
coated aspirin: keeps tablet intact
these & other factors affect efficacy
DRUG DESIGN:
Penicillin Discovered by Alexander Fleming in 1928
Culture dishes with the bacteria Staphylococcus were exposed to Penicillin notatum spores.
Where Penicillin notatum was growing, Staphylococcus was killed off (see Fig 10.10)
Named the stuff killing the bacteria “Penicillin”
Penicillin alternatives
About 20% of people are allergic to penicillin G. Common Alternatives are:
Ampicillin, Oxacillin, Cloxacillin, Penicillin O, Amoxicillin - very broadly used
Cephaosporins: cephalexin (Keflex) for resistant bacteria
Cyclosporine prevents tissue rejection in organ transplants
Salvarsan 606 : Start of Modern Drug Design
Paul Ehrlich: Knew arsenic kills syphilis, but kills victim!
SYSTEMATIC variation of structures of many arsenic compounds
Success: Compound 606: Arsphenamine
Drug Design Drugs come under two categories:
1. a physiological effect e.g., aspirin, hormones, “drugs”
2. inhibiting growth of infectious substances e.g., antibiotics: penicillin & alternatives
Many work only on specific diseases / infections
Why are drugs specific? The “Lock and Key” mechanism:
Action of Drug: A receptor site 'lock' accepts a hormone or protein ‘keys’, etc.
Some of these ‘keys’ are substrates : substances whose reactions are catalyzed by an enzyme.
Drug acts as dummy key; substrate cannot reach receptor site, so enzyme unable to act on substrate:
reaction stopped. A Hormone (or Drug imitating it) equal ‘keys’ which fit into the receptor site ‘lock’.
Effects of activation vary: open OR close a channel in cell, or affect chemistry inside cell, or may even kill
cell! Specific effect determines design of drug.
Drug Design: Pharmacophore
Three dimensional arrangement of atoms responsible for biological action of molecule
Once found, design / make simpler molecules with SAME pharmacophore.
COMPUTERS very widely involved!
Make a key - doesn’t have to be perfect!
Combinatorial Chemistry
Pharmaceutical companies create libraries of molecules to be screened for activity. A "Shotgun" approach.
The general approach can be shown considering just a two step reaction (see Fig 10.16). Use of computers
to optimize this (screen out poor candidates) means more compounds, more rapidly, for less $$.
CHIRALITY (Optical Isomerism) (Fig 10.17) Caused by a carbon atom bonded to FOUR DIFFERENT
groups. Two NONSUPERIMPOSABLE isomers form: called chiral/optical isomers or enantiomers
Labelled “L or - (left) ” and “D or + (right)” WILL BE MIRROR IMAGES of each other The two
enantiomers are affected DIFFERENTLY by polarized light
CHIRALITY and Drug Design- (Your Turn 10.16, Figs 10.19, 10.20, 10.21). Gives an added
complication! Synthesis often makes RACEMIC MIXTURE (equal amounts of each isomer) Often very
difficult to separate physically.
Often VERY different physiological effects!
Examples of Chiral Drugs Your Turn 10.7
Name
Active (desired) Form
Action
Effect of other form
Methorphan
D or +
non-addictive cough suppressant addictive opiate
Ibuprofen
L or pain reliever
no effect
Naproxen
?
pain reliever
liver damage
Dopa
D or +
treatment for Parkinson’s
much greater side effects
STEROIDS: a class of naturally occurring or synthetic fat-soluble organic compounds that share
a common carbon skeleton arranged in four rings
SEE NOTES ATTATCHED
Know about and be able to recognize structural isomers and optical isomers. What do you need for a
compound to be optically active (exist as a pair of structural isomers)? Can you find this feature in the
molecule?
Steroids: what are they, where are they made, and what do they do? How do "the pill" and RU486 work?
What do anabolic steroids do and what happens when you abuse them? Herbal Remedies: have a rough
idea what the claimed effect is for those mentioned in the table. Some are known to work to some degree
because of their active ingredients, others are still being verified.
What are the main concerns for taking a herbal remedy vs. a prescription or an OTC medication? How well
are these remedies regulated?
Generic vs. Brand name: know the active ingredient is the same, but the delivery method, coatings, binders
etc may vary.
Drug Testing: FDC approval process: have a rough idea of how this works: at what stage in the process do
we get to try this out on animals? people? sick people? Is the approval process 100% foolproof? How does
the timing of the approval process complicate things for a pharmaceutical company once they have
patented the drug (how long do they get to be the sole manufacturer?)
Drug Abuse: Which ones are considered the worst, Schedule 1 or 5 ?
Have a brief idea of the examples of prescription drug abuse given in class.
Know what a stimulant, narcotic, depressant, tranquilizer and halllucinogen are and some examples of
these.