Download Lex 4.1 Alcohols Thiols Ethers

Ch 12 Alcohols, Ether, Thiols
1. Naming
Functional Groups containing Oxygen
Functional Groups
• -OH hydroxyl group
• -O- ether
“
• C=O carbonyl
“
carboxyl “
Molecule Class
Alcohols
Ethers
Aldehydes, Ketones
Carboxylic Acid
Molecules and Functional Groups
containing oxygen
• have a bent shape
• are polar, soluble in water
• form H-bonds
I. Alcohols
• industrial ethanol production
Alcohol Naming -OH
5
4
3
2
H3C -CH2- CH2 –CH- CH2-CH3
1 CH2-OH
1. Find longest C-chain containing -OH group.
2. Name: drop the alkane ‘e’ replace with ‘-ol’
pentanol
3. Number: –OH is attached to lowest C number
Name: location-alkan-ol: 1-pentanol
4. Locate/list other substituents in front
2-ethyl-1-pentanol
Multiple Hydroxyls
• Include Carbon number
• add –di, -tri, -tetra….ol
• 1,2-propandiol
1,1-propandiol
Warm-up
A.)
B.)
A.) 3-methyl-2-pentanol
B.) 4-methyl-2,3-pentandiol
OH
Hydroxyls on alkenes/ynes
• OH group location overides double/triple
bond numbering
• Use the functional group name: Hydroxyl
• List alpha
• 2-Hydroxyl-4,4-dimethyl-trans-3-pentene
Phenol
• Benzene + Alcohol Group, must be called
Phenol
• Hydroxyl is always on C#1
Practice
2-methylphenol
Classification of Alcohols: Primary,
secondary, tertiary
-OH attached to
carbon with one other
carbon and two H
-OH attached to
carbon with two
other carbon and
one H
-OH attached to carbon
with three other carbon
and no H
Practice
• Draw the following alcohols in Kekule
1. 1-Hexanol
2. 3-Hexanol
3. 1,2,3-Hexantriol
• Name and classify as 1st, 2nd, 3rd alcohol
A
B
Sulfur Instead of Oxygen
• Same number of valence e• Same number of bonds as oxygen
• -SH is called a Sulfhydryl/Thiol group
Polarities
• EN of O: 3.5, S: 2.5, H: 2.1
Evaluate the polarities of the following bonds
1. O-H
2. C-O
3. C-S
4. S-H
5. C-H
C-S produces a ____ polar bond than C-O
Thiols -SH
• Longest carbon chain including thiol: lowest number
• Name: location-alkanethiol 1-propanethiol
• multiple: locations- alkanedithiol, -trithiol
1-propanethiol
2-methyl-1-propanethiol
2- propanethiol
-SH on complex Hydrocarbons
• List alpha as thiol, the highest oxidized group
determines numbering (O beats S)
SH
2-hydroxyl- 3-methyl- 4-thiol-trans-2-pentene
Ethers -O• Carbon chains on either side of ether are named
alkyls according to length followed by etherlocation not necessary!!!
• List alphabetically or use di- if identical
• diethyl ether
ethyl phenyl ether
ethyl methyl ether
2. Alcohols, Ethers and Thiols in
Nature
Alcohols in Nature
• Methanol: smallest alcohol in nature, toxic
• Ethanol: byproduct of alcoholic fermentation
(degradation of sugar in the absence of oxygen)
C6H12O6 → 2C2H5OH + 2CO2
Glucose
Ethanol
CO2 causes fizzing, leavening bread…
• Isopropanol: alcohol for disinfection, rubbing
alcohol
• Many flavors and aromas are alcohols: vanilla,
thymol (thyme) eugenol (cloves), menthol
Thiols in Nature
• Strong, borderline smells in nature are usually
Thiols: onion, garlic, aged cheese: break down
of amino acid Methionine
Ethers in Nature
• First anesthesia was done with diethyl ether
• Inhalation anesthesia
• Very volatile, and explosive
• Many side effects
• Not in use anymore
history of ether anesthesia
3. Polarity of Alcohols, Thiols and
Ethers
The Role of Oxygen
• Oxygen has the second highest
electronegativity of the PT: 3.5
Complete the table below: (EN: H: 2.1 and C: 2.5)
bond
C-H
∆EN
Polar/
nonpolar?
O-H
C-O
Polar Bonds = Polar Molecules!
• In order to be a polar molecule it needs to
have both:
a. Polar bonds and b. Polar symmetry
Polar Symmetries:
Net Dipole
Dipole
Bent
Pyrimidal
δδ+ δδ+
Characteristics of Alcohols, Thiols and
Ethers
• Oxygen containing functional groups makes
molecules polar!
(Sulfur is not very electronegative (2.5) so does not
make hydrocarbons very polar – only structural
asymetry)
• Hydroxyl will change the Melting, Boiling Point
and Solubility
Example:
• Methane: gas
• Methanol: liquid
4. Characteristics of Alcohols,
Thiols and Ethers
Melting/Boiling Point, Solubility in
Water
Characteristics of Hydrocarbons
•
•
•
•
Non-polar
Have low Melting/Boiling points
Do not dissolve in water
Only attractive forces are Van-de-Waals
Characteristics of Alcohols (to some
degree Thiols and Ether)
•
•
•
•
Are polar
Have a higher Melting/Boiling Point
Dissolve in water
Attractive forces include: H-bonds, Dipole
Interactions and Van-de-Waals
3 Intermolecular Attractions:
how they influence MP/BP and
solubility in water
1. Hydrogen bonds – strongest
intermolecular attraction
• Intermolecular attraction of adjacent polar
points (δ+, δ-) involving a Hydrogen
• Indicated by a dotted line
2. Dipole Interactions
• attraction of adjacent polar points δ+, δ- not
involving H
3. Van-De-Waals
attractions caused by very weak EN differences
(0.4 and lower)
Solubility in Water -A
• Requires Hydrogen Bonds
group polar
HC chain length vs # of OH-groups
 Long HC chains reduce polarity/solubility in
water
alkane chain: non-polar
alcohol group: polar
not soluble
so soluble
forms H-bonds
Solubility of alcohols vs HC
Dissolving Molecules in H2O
1. Draw the molecule in VSEPR
2. Draw in all partial charges (δ+, δ+)
3. Associate 1 (one) H2O molecule per each
δ+/- in the correct orientation (+ attracts -)
4. Draw in dotted lines
5. Example: Methanol
Type and number of intermolecular
attractions between molecules
determines MP/BP
Hydrocarbon
VdW
Dipole
H-Bond
+
-
Ether
Alcohols
+
+
-
+
+
+
Comparison of Alkanes, Ethers and
Alcohols
Compound
Molar mass
g/mole
BP
Soluble in H2O
Butane
58 g/mol
0 Celcius
no
Ethyl methyl ether
60 g/mol
8 Celcius
yes
Propanol
60 g/mol
97 Celcius
yes
Melting and Boiling Points
Fermentation
Fermentation
Warm-up
10 minute summary
How and why does alcohol affect the body and
how does the body deal with it.
You may want to address the following….
a) which organs/tissues are affected by alcohol?
b) which organs/tissues are responsible for
break down?
c) What are the long term affects of chronic
alcohol abuse?