Download R-OH

Organic Compounds
hydrocarbons (C,H)
heteroatomic (O, N, P, S, X, etc.)
or functional groups
aliphatic (fatty)
aromatic (pleasant smelling)
alkane
alkene
alkyne
C C
C C
C C
cyclic
Functional groups
• Functional groups are parts of
molecules that result in
characteristic features.
• Many functional groups exist, we
will focus on about 4.
Organic compounds having
functional groups
•
•
•
•
Alcohols
Carboxylic acids
Amino acids
carbohydrates
1. Alcohols
• a class of organic compounds with
an –OH (hydroxyl ) functional group.
• thus R-OH is the formula (The symbol “R”
is used to represent any carbon chains or
rings).
Alcohols
• condensed structural IUPAC
common
formula
formula name
name
H
CH4O
Methyl alc
methanol
H–C–O–H
C2H6O
H
H H
H–C–C-O–H
H
H
ethanol
Ethyl alcohol
Alcohols
• condensed structural IUPAC common
formula
formula name
name
C2H6O2
H
H
H–C–C–H
ethanediol
Ethylene gly
OH OH
H
C3H8O3
H
H
H–C– C- C–H
OH OH OH
propanetriol
glycerol
Naming alcohols
• For IUPAC:
–drop the -e ending of the parent
alkane name; add the ending -ol.
–Ethane
ethanol
H
H
H–C–C-O–H
H
H
Naming alcohols
• Alcohols containing 2, 3, and 4 of the - OH groups are named diols, triols,
and tetrols respectively.
H
H
H
H–C– C- C–H
OH OH OH
propanetriol
Naming alcohols
• Common names:
–name the alkyl group, then followed
by the word alcohol.
–One carbon alcohol = methyl alcohol
H
H–C–O–H
H
Properties of alcohols
• Much like water, alcohols are capable of
forming hydrogen bonding between
molecules. This means
–they will boil at a higher temp. than
alkanes with a comparable number of
C atoms.
–Alcohols of up to 4 carbons are
soluble in water in all proportions.
2. Carboxylic acids
O
• Functional group: - COOH or
- C – OH
(carboxyl group)
• General formula: R-COOH
• weak acids (ionize slightly)
Carboxylic acids
• Named by replacing the -e ending of
the corresponding alkane name with oic and followed by the word acid
• methanoic acid; ethanoic acid.
Carboxylic acids
• condensed structural IUPAC
formula
formula
name
CH2O2
C2H4O2
O
H - C – OH
H O
H – C -C – OH
H
common
name
methanoic
acid
Ethanoic acid
Formic acid
Acetic aci
3. Amino acids
• Functional groups: - NH2 (amino) and
O
- C – OH (carboxyl).
Amino acids
• condensed structural
formula
formula
H O
C2H5NO2 H2N - C - C – OH
H
C3H7NO2
H O
H2N - C - C – OH
CH3
common
name
glycine
alanine
4. Carbohydrates
O
• The functional group is
O
or -C – H
(aldehyde).
-C–
(carbonyl)
Carbohydrates
H
H–C–OH
C=O
HO – C – H
H – C – OH
H – C – OH
H – C – OH
H
fructose
H–C=O
H – C – OH
HO – C – H
H – C – OH
H – C – OH
H – C – OH
H
Glucose, C6H12O6
Hydrophilic groups
• Hydrophilic means “water loving.”
• Hydrophilic groups are electrically polarized.
This makes the substances including a
hydrophilic group soluble in polar solvents
like water.
• Examples: - OH, - COOH, - NH2
Hydrophobic groups
• Hydrophobic means “water hating.”
Hydrophobic groups are not electrically
polarized. Therefore, hydrophobic substances
are not soluble in water but soluble in nonpolar solvents like benzene.
• Examples: alkanes, ethylene, acetylene, CCl4,
oils, and fats.
Hydrophilic and hydrophobic groups
• The common soap is the Na salt of stearic
acid. Its formula is: CH3(CH2)16COONa.
• When it dissolves in water, it produces Na+
and CH3(CH2)16COO- ions.
–CH3(CH2)16 COO
Hydrophobic tail
Hydrophilic
- head
Hydrophilic and hydrophobic groups
oil
oil
Micelle
Hydrophobic tails dissolve oil. Hydrophilic heads stay
away from oil but attracted by water molecules. So, the
oil is washed away by soap and water.
Micelle
oil
References
• www.chalkbored.com/lessons/chemistry12/functional-groups.ppt
• www.cottonchemistry.bizland.com/.../Chapter
%2023%20Functional%20Groups.ppt
• http://www.hastings-on-hudsonfiredept.org/F500/images/f500_micelle.jpg