CHAPTER
ONE
INTRODUCTION
1.1 Background
of the study
Yams (Discorea spp) of the family Diocoreaceae are members
of the flowering plant. They are monocots, related to palms, grasses and
archids. Most yam species grow in the tropics and subtropics area with fairly
heavy total annual rainfall, but with a definite day season. During the rainy
season, they produced one or more underground tubers to store food and water
through the dry season the tubers are thickened stems. Most yam plant have
small flower with one plant having only male or female flower (Kay, 1987).
The tubers of most species of yam are poisonous to humans.
The cultivation of most yams is very labour intensive. Cultivated yams
generally do not produce seed and so tubers or pieces of tuber must be planted
in prepared soil, most often in wounds to grow new plants.
Yams are nutritious food, providing carbohydrate, some
protein, and mineral like phosphorus and potassium besides the use as food,
yams have been symbolically associated with culture and ritualism in some parts
of Africa, Asia and Latin Americas.
According to Ogbuka (2005) Ethanol can
be produce from starch –containing substances like maize, cassava and yam.
Ethanol is a monohydric alcohol that is colourless and flammable, it is a 2
–carbon alcohol with molecular formular CH3 CH2 OH, its
empirical formular is C2H6O. An alternative notation is
CH3CH2 OH which indicates that the carbon of a methyl
group (CH3) is attached to the carbon of an ethylene group (CH2-)
which is attached to the oxygen of a
hydroxyl group (OH). Ethanol is a colourless liquid that burns with a smokeless
blue flame. It has a choking smell and a boiling point of 780c. They
are characterized by the possessing of phydroxyl group (OH) as their functional
group. Alcohols can be classified as primary, secondary and tertiary. The
primary alcohols have only one or no alkyl group attached to the hydroxyl
bonded carbon atom, the secondary alcohol contain two alkyl group attached to
the hydroxyl bonded carbon atom while the tertiary alcohol contains three alkyl
groups but no hydrogen attached to the hydroxyl- bonded carbon atom while the
tertiary alcohol contains three alkyl groups but no hydrogen attached to the
hydroxyl-bonded carbon atoms:
According to West et.al (2007) ethanol
is a principle fuel that can be used as petrol substitute for vehicles. It is a
renewable energy source produced mainly by sugar fermentation process. It is
used in preservation of specimen, food e.t.c and even as a raw material in the
manufacturing of chemicals and pharmaceuticals like trichloromethane
1.2 Statement
of the Problems
Alcohol has been known to be produced
from fossile like maize, cassava, even yam tuber but there is still need to
search for other sources considering the usefulness of ethanol source, hence
the need for this study. Furthermore, yam peel are regarded as waste after
using the main yam tuber, therefore there is need to source for alcohol in this
peel which either are throw away. This study will also reduce environmental
pollution which is caused by the yam peel.
1.3 Objectives
of the Study
Objectives of this study include:
vTo extract ethanol from yam peel
vTo carry out qualitative test on the
produced ethanol
1.4 Significant
of the Study
The knowledge from this study will help
in creating awareness to the government as well as the society at large on the
need to grow more yams. Finally this study will also help the society to know
that ethanol is not just present in the yam tuber alone but also in the peels
(yam peels)
1.5 Scope
of Study
This study is concerned with the
production of ethanol using yam peel which involves
vCollection and identification of the
sample
vPreparation of the sample
vProduction of ethanol from the sample
vQualitative tests on the produced
ethanol.