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By treating sodium sulphite or bisulphite
with dilute sulphuric acid or
hydrochloric acid
The apparatus is set up as shown in figure 7.1.
Sodium sulphite or bisulphite is taken in a round
bottom flask. Dilute sulphuric or hydrochloric acid is
added through the dropping funnel and heated gently.
SO
2
vapors get displaced upwards and are passed
into a jar containing concentrated sulphuric acid. The
gas is dried here and is collected by the upward
displacement of air in the second jar.
By treating copper with hot concentrated
sulphuric acid
The apparatus is set as shown in figure 7.2. Copper
turnings are taken in a round bottom flask.
Concentrated sulphuric acid is added through the
dropping funnel and the flask is carefully heated.
Chemical reaction occurs and SO
2
vapours get
displaced upwards.
The sulphur dioxide formed is then passed through

concentrated sulphuric acid, to dry the gas. The gas is
collected by the upward displacement of air.
Note:-
• At the end of the reaction the residue left behind
is copper sulphate, which is normally blue in color.
In the presence of excess concentrated sulphuric
acid, it may get dehydrated into grayish white color.
• However, in practice the residue left behind is
black in color! This is due to the partial reduction of
copper sulphate into copper sulphide, which is black
in color.
/>Function
The pellets are preheated and crystallized in the crystallizer (1), which is also used as an
intermediate storage for the preheating unit (2). With the reactor connected to the vacuum
unit (3), the pellets are transported in batches from the crystallizer to the preheating unit
on top of the reactor, where the pellets are heated above reaction temperature und
subsequently transferred to the vessel (4).The specially designed reactor outlet floor (5)
guarantees constant treatment times and therefore a consistent iV increase. After the
reaction time, which can be adjusted, the material is transported in batches to the cooler
(6), where it is cooled either below reaction temperature and dispatched directly without
additional drying to a processing machine or, after further cooling, dispatched to an
intermediate storage silo.


Chemistry 331 - Fall 1996
Homework, Chapter 2 - Alkanes
McMurry, pp 65 - 69:
Problems 2.24, 25, 28, 29, 33, 34, 35, 38, 40, 41, 46, 48, 50, 53, 54
See the Study Guide for help with the text problems.

1. Each of the names shown below is incorrect. Deduce the compound to which the
name refers, and give its correct IUPAC name.
a) 4-methylhexane
b) 2-ethylpropane
c) 1,1,2-trimethylbutane
d) isopropylethane
e) 2-chloro-2-ethylpentane
2. Give complete IUPAC names for each of the following compounds:
(note-the bonds have been shifted to the left on the lines below, but you should be
able to figure out where the substituent on the lower line attaches to the upper line -
or see your real homework handout, of course)
a) CH3-CHCl-CH2-C(CH3)2-CBrCl-CH-C(CH3)3
|
CH2-CH2-CHCl-CH3
b) Cl3C-CH2-CHF-C(CH3)-CCl3
|
CH2-CH(CH3)2
3. Write out structural formulas for all of the
isomers that have the molecular formulas
shown below. Identify each of the functional
groups present, but you need not name any of
the compounds.
a) C3H6Cl2
b) C3H6O
c) C2H3N

Common or trivial system
The monohalogen derivatives of alkanes are called
alkyl halides. Their names are derived by naming the
attached alkyl group to halogen and adding the name

of the halide. For example,
The name of the alkyl and halide is written as two
separate words. The prefixes n-, iso-, sec-, tert-, etc.
are also used for alkyl groups and are written as:
The prefix n- is used for alkyl group having continuous
chain of C-atoms with no branching.
The prefix iso- is used for those alkyl groups wherein
one methyl group is attached next to the end C-atom.
The prefix neo- is used for those alkyl groups which
have two methyl groups attached next to the end C-
atom.
IUPAC System
Here, the monohalogen derivatives of alkanes are
named as haloalkanes. While writing the names, the
word 'halo' is prefixed to the name of the alkane
corresponding to the longest continuous carbon chain
holding the halogen atom. In case of branched chain
alkanes, the following rules are followed:
• The longest continuous chain containing the
carbon attached to halogen group is selected as the
parent alkane.
• The carbon atom is numbered in a way that the
carbon atom carrying the halogen atom gets the
lowest number.
• The position of the halogen atom and other
substituents (alkyl groups) are indicated by suitable
numbers i.e., 1,2,3 etc. Other common rules of
alkanes are followed. For example,
The common and IUPAC names of a few
alkyl halides are given below

Amyl is used for CH- group.
The halo compounds have other names too based on
the type of structural and substituent effects.
Hydrogen atoms
Sometimes hydrogen atoms have special names such
as vinylic hydrogen (attached to double bonded C-
atom), allylic hydrogen (attached next to double
bonded C-atom). The replacement of halogen atom
for these types of hydrogen atoms results in alkyl
halides having the corresponding common names.
Dihalogen alkanes
These alkanes also have special common names
when both the halogen atoms are attached to the
same C-atom. These are called 'gem-dihalides', or
are also called alkylidene dihalides or simply,
alkylidene halides.
Also, when two halogen atoms are at adjacent C-
atoms, they are called vicinal dihalides. These are
named as the dihalide of the alkene from which they
may be prepared by the addition of halogen atoms i.e.
alkylene dihalide or simply alkylene halide. For
example,
Polyhalogen derivatives are named as per IUPAC
system.
Classification of alkyl halides
Depending upon the nature of carbon atom to which
the halogen is attached alkyl halides or haloalkanes
are classified as :
Primary (1
o

) haloalkanes
These are alkyl halides that have one or no alkyl
group on the carbon linked to the halogen atom.

Secondary (2
o
) haloalkanes
These are alkyl halides that have two alkyl groups on
the carbon linked to the halogen atom.

Tertiary (3
o
) haloalkanes
These are haloalkanes that have three alkyl groups
on the carbon linked to the halogen atom.
Haloarenes or aryl halides are named by adding the
prefix 'halo' (fluoro, chloro, bromo, iodo) before the
name of the aromatic hydrocarbon. In case of di-
substituted compounds, the relative positions of the
substituents 1,2; 1,3 and 1,4 are indicated by the
prefixes ortho (o-), meta (m-) and para (p-)
respectively. For example,
/> />ORGANIC CHEMISTRY
II
CHEM 2325
ALDEHYDES and KETONES
INTRODUCTION
Aldehydes are easily oxidized and more reactive than ketones.
Ketones are more difficult to oxidize and are less reactive than aldehydes.
The structure of the aldehyde and ketone is a sp

2
NOMENCLATURE
Aldehydes: common names
The common names of aldehydes end with the word aldehyde and are based on the name of the carboxylic acid
they are derived from.
Aldehydes: IUPAC names
The IUPAC names end with -al.
Aldehydes: Aromatics
The aromatic names of aldehydes are often derived from the common
names. If there are two names listed, the first is the common and the
second is IUPAC. If only one name is listed, it serves as both the IUPAC
and common.
Aldehydes: More complex
Many times it is too difficult to name an aldehyde using the common
names, so it defaults to the IUPAC system. But, many times the common
name system of numbering is used in which Greek letters are substituted
for the numbers. The carbonyl group always gets the number one position,
while the Greek letters (a,b,g,d) are used in the common names starting at
the second carbon (first available carbon for a side group).
Ketones: Common names
The simplest ketone is called acetone. The other names of ketones list the
two groups on each side of the carbonyl group followed by the word
ketone. A ketone in which the carbonyl group is attached to a benzene ring
is named a -phenone.
Ketones: IUPAC names
The longest chain containing the carbonyl group is considered the parent
structure and the -e is replaced by -one. The carbonyl group is given the
lowest possible number.
PHYSICAL PROPERTIES
The polar carbonyl group makes ketones and aldehydes polar.

As the molecular weights increase, so do their melting and boiling points.
They have lower boiling points than comparable alcohols or carboxylic
acids.
The lower aldehydes and ketones are appreciably soluble in water and
borderline solubility is reached at about five carbons. They are soluble in
the normal organic solvents.
Formaldehyde is a gas at room temperature (BP -21
o
C) and is used either
as an aqueous solution (formalin - formaldehyde dissolved in methanol), or
one of its solid polymers: paraformaldehye or trioxane (when heated they
break down into formaldehyde).
PREPARATION OF ALDEHYDES
1. Oxidation of primary alcohols
2. Oxidation of methyl benzenes
3. Reduction of acid chlorides
PREPARATION OF KETONES
1. Oxidation of secondary alcohols
2. Friedel-Crafts acylation
3. Reaction of acid chlorides with organocopper compounds
MECHANISM OF FRIEDEL-CRAFTS ACYLATION