“Their Structures, Physical Properties
Structure and Physical
An organic compound containing a
hydroxyl group attached to an alkyl group.
a non-polar (alkane-like) chain.
a polar hydroxyl group.
Alcohols have the general formula: R-OH, where ―R‖ involves a saturated
C-atom (bound to hydrogen's and/or other carbons).
Classification of alcohols
• Alcohols may be classified as 1o (Primary), 2o (Secondary), or 3o
(Tertiary), by considering the number of carbons bound to the
•Ethanol is a primary alcohol because there is only one alkyl
group attached to the carbon that carries the OH substituent.
•The isopropyl alcohol found in rubbing alcohol is a secondary
•An example of a tertiary alcohol is tert-butyl (or t-butyl) alcohol or
R-O-H has a structure similar to that of water
Higher boiling points.
Classification of alcohols
We already saw that the boiling points of alkanes increase with increasing
chain length. The same is true for alcohols.
Alcohols with more than one hydroxyl group (polyhydroxyl alcohols) have
higher boiling points than monohydroxyl alcohols.
The Lower the molecular weight of alcohols, the higher the
solubility in water.
The water-solubility of alcohols depends on the length of the
alkyl chain in the alcohol.
alcohols having chains longer than four carbons are not very
3-4 carbons or less— ARE soluble in water
Alcohols having chains SHORTER than four carbons are very watersoluble…
Methanol is Soluble and Miscible in water…
Alcohols having chains LONGER than
Three carbons are not very watersoluble…
Butanol is Soluble but not Miscible in
Solubilities of ALCOHOL in water
Water (g/100 g)
insoluble in water
Comparison between the Boiling points and
Solubility of ALKANES and ALCOHOLs
Structu ral Formula
ins olub le
CH3 CH2 OH
CH3 CH2 CH3
CH3 CH2 CH2 OH
CH3 CH2 CH2 CH3
ins olub le
CH3 CH2 CH2 CH2 OH
8 g/100 g
CH3 CH2 CH2 CH2 CH3
ins olub le
ins olub le
Phenols are compounds in which the hydroxyl group is attached to a
Phenol is the simplest member of a family of compounds in which an OH group is attached directly to a benzene ring.
Structure Of Phenol
Pure phenol is a white crystalline solid, smelling of disinfectant. The
crystals are often rather wet and discolored.
Phenols have the formula Ar-OH
Ar must be an aromatic ring (e.g., Benzene)
Widely used in healthcare as:
Melting and boiling points
high melting and boiling points
filesmy academic files (2013-2014)MY chem reports (organic Chem)ACTUAL REPORTattachment.pptx
Hydrogen bonds can form between a lone pair on an
oxygen on one molecule and the hydrogen on the -OH
group of one of its neighbors.
Solubility in water
Phenol is moderately soluble in water - about 8 g of
phenol will dissolve in 100 g of water.
Phenol is somewhat soluble in water because of its
ability to form hydrogen bonds with the water.
Ethers are a class of organic compounds characterized by an oxygen
atom connected to two hydrocarbon groups.
Ethers do not H-bond with themselves, so have boiling points similar
Ethers are only slightly soluble in water and are highly flammable
An ether is a characterized by an oxygen bonded to two alkyl or aryl
groups, represented here by R and R'.
The substituent's can be, but do not need to be, the same.
Ethers can act as a hydrogen-bond acceptor,
as shown in the figure on the right. But, they can't
act as hydrogen-bond donors.
Less likely to be soluble in water than the alcohol with the same
The absence of an -OH group in an ether also has important
consequences for its chemical properties.
Ethers are essentially inert to chemical reactions. They don't react with
most oxidizing or reducing agents, and they are stable to most acids
and bases, except at high temperatures.
However, extremely FLAMMABLE explode if exposed to air for longer
periods of time, to form EXPLOSIVE PEROXIDES.
Melting and Boiling points
Boiling points and melting points are dictated by intermolecular forces.
Compared with alkane of similar molar mass, an ether will have a
similar boiling point.
Compared to an alcohol of the same molar mass, the ether will have a
much lower boiling point.
Medical use of Ethers
Ethers are often used as anesthetics
Accumulate in the lipid material of nerve cells
interfering with nerve impulse transmission.
Today halogenated ethers are used routinely
as general anesthetics
Safer to store and to work with
Name the C-atoms of a single alkyl group as for alkanes.
Add the word ―alcohol‖ following a space after the alkyl name.
2) CH3 CH2--OH
Alcohols with more than one OH group
Polyhydroxyl alcohols possess more than one OH group.
Alcohols which possess two OH groups are called ―diols‖ and those
with three OH groups are called ―triols‖
Naming this kind of Compound is simple, just follow this:
Alkane name + the number of the OH
Name the parent compound.
Replace the –e with –ol.
Number the ring to minimize number of carbon with the –OH group
Identify, name, and number all substituent/s.
Six Carbon ring= Cyclohexane
OH must be at C-1
methyl on C-3
Compounds with additional substituent's are named as substituted
when there is only one other substituent, Ortho, Meta or Para are
Mono-substituted phenols are characterized using the prefix ortho
(o-), meta (m-) or para (p-) depending on the placement of the
substituent from the hydroxyl group.
para : (1,4-)
The simplest member of phenol is called phenol itself or
hydroxybenzene and the rest are named as its derivatives.
If there are two or more additional substituent's, each must be
numbered, beginning at the OH and going in direction that gives
substituent's lowest numbers (or alphabetical if same in both
Functional group suffix = -common - phenol, systematic benzenol
Functional group prefix = hydroxy
di , tri and so forth are used to denote the number of substituent.
NOTE: Many have common or trivial names that do not at all suggest
For common names:
name each alkyl group
attached to the oxygen followed by ether.
Ethyl methyl Ether
Methyl phenyl Ether
For complex ethers IUPAC names are used
Step1: Name as an alkane, with larger alkyl group being the parent
Step 2: Find the smaller alkyl group and the O are named together
as an alkoxy group (replace -yl with -oxy)
e.g., CH3CH2O = ethoxy
Step 3: Number chain starting at end nearest alkoxy group
Step 4: Use a number to give location of alkoxy group
Try this one:
Naming Cyclic Ethers
Cyclic ethers are generally named by their common
A cyclic ether containing two carbons is called ethylene
oxide (generally known as epoxides)
A cyclic ether containing 4 carbons (with 2 double
bonds) is called a furan
A cyclic ether containing 5 carbons (with 2 double
bonds) is called a pyran
A cyclic ether containing 4 carbons and 2 oxygens is
called a dioxane
PHENOLS are next-generation anti-oxidant found throughout
nature in some of the healthiest foods.
PHENOLS are the common health-giving link that ties together
foods, such as Red Wine, Green Tea, Dark Chocolate, and SuperBerries.
In human health these compounds are thought to be instrumental in
combating oxidative stress, a process associated with some
neurodegenerative diseases and some cardiovascular diseases.
Approximately 600,000 students per year are assaulted
by a drinking student.
Research suggests that women are more vulnerable than
men to many alcohol- induced problems. Some of these
include, Organ Damage, Trauma, Legal and interpersonal
Alcohol affects men and women differently. Women become
more impaired than men from drinking the same amount of
alcohol. This is because women:
• Are generally smaller in size
• Have less body water
• Have less dehydrogenase.
• Have more estrogen
Alcohol is a central nervous system depressant. In small
amounts it can have a relaxing effect.