MLSINOR01, BSMT 1 - Lymphocytes
Mr. Clint Eleazer Ricarse
Short Background: Properties
A l d e h y d e s are c o m p o u n d s w i t h a terminal carbonyl
(H C = O ) m o i e t y, a n d a r e either u n s a t u r a t e d , c o n t a i n s o n e
o r m o r e c a r b o n -c a r b o n d o u b l e b o n d s , o r s a t u r a t e d t h a t
c o n t a i n s a single b o n d .
O n e of the oldest k n o w n aldehydes wa s first
produced in 1774 by Carl Wilhelm Scheele, although
its structure wa s not completely completely
understood until 60 years later wh e n Justus von
Liebig determined its constitution, described its
preparat i on f r o m e t h a n o l a n d g a v e t he n a m e
“aldehydes” to the chemical group
It is m ainly derived f r o m the dehydration of
a l c o h o l s a n d is actually c o n s i d e r e d t h e m o s t
important functional g ro u p . T h e reactivity of
these c o m p o u n d s arises largely t h r o u g h t w o
features of their structures: the polarity of the
carbonyl group and the acidity of any ahydrogens that are present.
Aldehydes are polar molecules and m a n y
reagents s eek a t o m s wi t h a deficiency of
electrons. The general formula for
aldehydes is CnH2n+1 C H O or C n H 2 n O .
Functional Groups
One of the most important
functional group in organic
chemistry is the carbonyl group:
The carbonyl group is present in the aldehydes and ketones.
The carbon of the carbonyl group must be connected to two
other atoms or groups. The compound is called an aldehyde
when it is connected to a hydrogen and an alkyl group or
aromatic ring (or to two hydrogens).
Proper IUPAC/Common Naming (Steps)
1 . Aldehydes take their n a m e f r o m their parent alkane
chains. T h e -e is r e m o v e d f r o m the e n d a n d is replaced
with -al.
2. T h e aldehyde functional group is given the #1
numbering location and this number is not included in
the n a m e .
3 . For the c o m m o n n a m e of aldehydes start
w i t h the c o m m o n p ar e n t c h a i n n a m e a n d a d d
the suffix -aldehyde. Substituent positions are
shown with Greek letters.
4 . W h e n the -C H O functional group is attached
to a ring the suffix -car
5 . b a l d e h y d e is a d d e d , a n d t h e c a r b o n
attached to that g r o u p is C 1 .
The IUPAC system names
are given o n top while
the c o m m o n n a me is
given o n the bottom in
parentheses:
There are s o me c o m m o n
n a m e s that are still us ed
and need to be
memorized.
R e c o g n i z i n g the
patterns c a n b e helpful.
T h e s e are the a l d e h y d e
c o m m o n names to
memorize.
Writing of Structures
A n aldehyde has a functional group of C H O .
W h e n writing the structure, carbon (C ) is
double
b o n d i n g with o x y g e n (O ) a n d single b o n d i n g
with hydrogen (H ). We should always k n o w that
the c a r b o n in the functional g r o u p is a l w a y s the
first carbon.
The general formula of alkene is C n H 2 n + 1 and as
aforementioned, the general formula for aldehyde
will be CnH2n+1CHO or CnH2nO which will be a
great basis in writing the structure.
T h e structure w e see above is an example of
a n aldehyde n a m e d as f or ma l de hyde w h i c h
is the simplest aldehyde. We can see that
the structure has a carbon a t o m w h i c h has
single bonds to two hydrogen atoms in
different sides a n d has a double b o n d with
oxygen.
In all other aldehydes, the carbonyl
g r o u p is b o n d e d to o n e h y d r o g e n a n d
o n e c a r b o n g r o u p . A carbonyl g r o u p is a
f unctional g r o u p c o m p o s e d o f a c a r b o n
a t o m d o u b l e -b o n d e d t o a n o x y g e n
atom: C =O
T h e structure w e see a b o v e is another
e x a m p l e of a n a l d e h y d e k n o w n as
acetaldehyde. W h e n writing its structure, the
c a r b o n y l g r o u p (C = O ) is b o n d e d to o n e
hydrogen and one carbon group.
EXAMPLES: COMMON/IUPAC NAMES, STRUCTURES & USES
Methanal ( IUPAC ) Formaldehyde (C o m m o n ): C H 2 O
- It is naturally used as an aqueous solution containing
37% methanal, known as formalin. It
contains a small a m o u n t of methanol a n d an inhibitor to
prevent aldehyde f r o m forming long
chain p o l y m e r s o n storage. It has o n e car b o n a t o m , t w o
hydrogen atoms and one oxygen atom.
Ethanal ( IU PA C ) Acetaldehyde
(C o m m o n ):C H 3 C H O or C 2 H 4 O
- used as starting mater ial a n d it h a s b e e n
m a n u f a c t u r e d b y hydr ation of acetylene
a n d oxidation o f e t h a n o l
Benzenecarbaldehyde (I U PA C )
Benzaldehyde (c o m m o n ): C 6 H 5 C H O
- A n organic c o m p o u n d consisting of a
benzene ring with a formyl substituent. It is
used in the production of d y e s , soaps a n d
p e r f u m e s . It is also used in cakes a n d b a k e d
g o o d s a s a l m o n d extract.
Pentanal ( I U PA C ) Valeraldehyde
(common): C5H10O
-It is a s at u r at ed fatty a l d e h y d e c o m p o s e d
from five carbon in a straight chain. It is
used in flavorings, resin chemistry and
rubber accelerators. Its smell is described
as fermented, bready, fruity, nutty and
berry.
Butanal (IUPAC) butyraldehyde
( common): C H 3 (C H 2 )2 C H O
- A p p e a r s as a clear liquid w i t h a p u n g e n t
odor. Less dense that water an d insoluble in
water, vapor heavier that air. It is also
m a i n l y u s e d as a n intermediate in the
production of synthetic resins, rubber
vulcanization accelerators, solvents a n d
plasticizers.
Propanal ( I U PA C ) Propionaldehyde (
common ): C H 3 C H 2 C H O
- It is the 3 carbons aldehyde. It is a
colorless, flammable liquid with a slightly
fruity odour. It is used in the manufacture of
plastics, in the synthesis of rubber chemicals
a n d a s a disinfectant a n d p r e s e r v a t i v e .
2- Chloropentanal (I U PA C ) achlorovaleraldehyd( c o m m o n ):C 5 H 9 C I O
- S o m e h o w used to m a k e insulation and
plastic d i n n e r w a r e .
3- Methylbutanal ( IUPAC )
isovaleraldehyde ( c o m m o n ):
(C H3 )2 C H C H 2 C H O
- It is butanal substituted by a methyl
group at position 3 . It occurs as volatile
constituent in olives. Also produced
c o m m e r c i a l l y a n d is u s e d as a reagent for
the p r o d u c t i o n o f p h a r m a c e u t i c a l s a n d
pesticides.
4- Hydroxybutanal ( IUPAC ) Bhydroxybutyraldehyde ( c o m m o n ):
C4H8O2
- T h e hydroxybutanal molecule contains
a total of 1 3 b o n d s , 3 rotatable b o n d s , 1
d o u b l e b o n d (s), a a l d e h y d e (aliphatic ),
1 hydroxyl groups and 1 primary
alcohols. It was formerly used in
m e d i c i n e a s a h y p n o t i c a n d sedative.
2-Chlorobutanal (IUPAC ) B chlorobutyraldehyde ( c o m m o n ):
C4H7CIO
- A n alcohol based preservatives with
no surfactant activity. It also elicits
sedative- h y p n o t i c a n d w e a k local
anesthetic actions. It is widely used as a
c h e m i c a l preservative for injectable
drugs, eye drops, m o u t h washes and
cosmetics.
Members:
Exija, Lester John C.
Managuit, Thrilla Dawn L.
Paredes, May Catherine A.
Pascual, Oriel D.
Pillo, Aennylou
Rojo, Aj Vhert
Esmeralda, Myrel Joy A.
Balitor, Glovin Adrian V.
Genolos, Ronest Angel N.
Guarino, Ana Mariel S.
Isio, Carl John M.
Magon, Angel Ann F.
Navales, Henryl Jane A.
General References:
h t t p s : / / w w w. v e d a n t u . c o m / c h e m i s t r y / p h y s i c a l - p r o p e r t i e s - o f - a l d e h y d e s , h t t p s : / / w w w 2 . c h e m i s t r y. m s u . e d u / f a c u l t y / r e u s c h / v i r t t x t j m l / a l d k e t 1 . h t m
h t t p s : / / s t u d y. c o m / a c a d e m y / l e s s o n / a l d e h y d e - d e f i n i t i o n - r e a c t i o n s - f o r m u l a - s t r u c t u r e . h t m l , h t t p s : / / b y j u s . c o m / c h e m i s t r y / a l d e h y d e s
h t t p s : / / g u i d e s . h o s t o s . c u n y. e d u / c h e 1 2 0 / c h a p t e r 3