Chapter III
Materials and Methodology
A. Materials and Equipment
Materials
Equipment
Orange Peelings
Direct Steam Distillation Set-up
Appliance Styrofoam
thermometer
Water
Thermometer adapter
Sidearm adapter
Boiling flask
Heating mantle
Condenser
Vacuum adapter
Receiving flask
Wire or rubber band
Triple beam balance
Rules, cutter, scissors
B. Procedure
The conduct of the research will take four phases. These phases include the -
a)
preparation of samples to be investigated, b) determination of density, durability, and thermal
conductivity of the samples through calculations, c) determination of the color and texture
through a survey, and lastly d) comparison of the gathered characteristics using inferential
statistics. The detailed description of each phase is provided below.
Preparation of Samples
The researcher will get home appliance Styrofoam and cut six (6) rectangular prisms of
dimensions A”xB”XC” out of it. Three of the prisms will be used as the controlled variable
(undissolved sample). The other three will be dissolved using limonene as solvent (experimental
variable). The limonene will be extracted from the peelings of orange fruits. Extraction shall be
done using Direct Steam Distillation (Marmor, 1981). The procedure for such technique is given
in the section below.
However, as soon as limonene will be extracted from the orange peelings, ___ mL of
limonene shall be introduced into three of the of Styrofoam prisms. The prisms shall be allowed
to dissolve and solidify again. The combination of the limonene and Styrofoam shall now be the
experimental set-up.
Isolation of Limonene from Orange Peelings (Direct Steam Distillation)
Peel the skin off the oranges and weigh it. The best results are obtained if a fresh
Valencia orange is used. Construct an apparatus for "direct steam distillation", as shown below.
Place the peel in a blender with about 150 ml of water and blend for about 30 sec.
Transfer the slush to the 500 mL distillation flask, using an additional 50 ml of water as a rinse.
The flask should be no more than half full or it may boil over during distillation. Heat the
mixture to a boil and begin the distillation. Record the temperature after the 1st drop is collected
and again after around 20 drops have been collected. At the beginning of the distillation, the
mixture may come over cloudy as limonene separates from the water. Continue the distillation
until at least 25 ml has been collected and the distillate coming over is clear. The continued
presence of limonene in the distillate can best be determined by collecting approximately 1 ml in
a test tube and looking for small oil droplets as the test tube is agitated.
Transfer the distillate to a separatory funnel. Let the funnel stand for about 5 minutes to
allow complete separation of the layers. Carefully drain off and discard the lower, aqueous layer.
Transfer the oily organic layer out of the top of the funnel into a small, tared conical vial using a
9" Pasteur pipette and determine the weight of the limonene. Avoid transferring water with the
limonene. If water is transferred, decant the limonene into a new tared vial. If water is still
present treat with anhydrous magnesium sulfate of sodium sulfate, pipette the limonene to a dry
tared vial and weigh again. Calculate the percent recovery of limonene.
Obtain an infrared spectrum and either the refractive index or a microboiling point as
your lab instructor suggests. Correct the refractive index to the standard temperature of 20
degrees Celcius. Compare the corrected value with the literature value at 200C. Measure the
observed optical rotation by weighing limonene into a 10 ml volumetric flask and adding hexane
to the mark. After mixing, fill a 1-dm polarimeter cell with your solution, find the observed
optical rotation, and calculate an experimental specific rotation. Calculate the experimental
specific rotation as a percentage of the value reported in the literature (% optical purity).
Determination of Sample Characteristics
Density. The density of all the samples shall be determined by obtaining the mass of the
sample and dividing it to its volume. The mass shall be obtained using triple beam balance and
the volume shall be mathematically calculated using the formula:
𝑉𝑝𝑟𝑖𝑠𝑚 = (𝑙𝑒𝑛𝑔𝑡ℎ)(𝑤𝑖𝑑𝑡ℎ)(ℎ𝑒𝑖𝑔ℎ𝑡) (eq. 1)
Upon obtaining the mass and the volume, the researcher will use the density formula to get the
density for both the dissolved and undissolved samples. The said formula is given below:
𝐷𝑒𝑛𝑠𝑖𝑡𝑦 =
𝑚𝑎𝑠𝑠
𝑣𝑜𝑙𝑢𝑚𝑒
(eq. 2)
Durability. The durability of the samples will be determined base on the amount of
weight the samples could carry before it breaks. The samples will be elevated using planks on
both sides. Increasing weights shall be placed in the middle part of the sample where no support
is placed. The researchers will record their observations during a particular weight is being
placed in a table provided below.
Weight
Observation
10 N
20 N
30 N
40 N
Thermal Conductivity. In physics, thermal conductivity, k, is the property of a
material's ability to conduct heat. It appears primarily in Fourier's Law for heat conduction. Heat
transfer across materials of high thermal conductivity occurs at a faster rate than across materials
of low thermal conductivity. Correspondingly materials of high thermal conductivity are widely
used in heat sink applications and materials of low thermal conductivity are used as thermal
insulation.
A direct measurement may be made by taping a thermometer to the samples and then
submerging the item partially in hot water. The recommended tape to use is electrical or masking
or something similar. Every few seconds, record the temperature and the time. Make a graph of
temperature versus time for every item, and use the results to make a visual comparison on how
quickly each one became hot (www.ehow.com). The researcher will record the change in the
sample’s temperature per time interval.
Now, using the data gathered from the experiment, the researchers will now use the
formula for heat conduction to derive the value of the samples thermal conductivity, k. The
formula is given below.
𝑄
𝑡
=
𝑘𝐴(𝑇ℎ𝑜𝑡 − 𝑇𝑐𝑜𝑙𝑑 )
𝑑
(eq. 3)
Color and Texture. The color and texture of the samples shall be determined using
survey method. The researchers will gather 30 respondents; all are IDS students, through
convenience sampling. The researchers will present the dissolved and undissolved samples
before them. The respondents will then rate the samples base on its color and texture using a
scale. The results shall then be the basis of the representative color and texture of the samples.
Comparison of Characteristics
Comparison of characteristics shall be done using tools used in inferential statistics. Both
parametric and nonparametric tests are to be used in the comparison of the characteristics of the
samples. Parametric comparison of values shall be done for the density, durability, and thermal
conductivity of the samples. Non-parametric test shall be used, on the other hand, in comparing
the color and texture of both dissolved and undissolved samples. The two inferential tools that
will be used in this research are:
T – test. The t-test (or student's t-test) gives an indication of the separateness of two sets
of measurements, and is thus used to check whether two sets of measures are essentially different
(and usually that an experimental effect has been demonstrated). In the context of the research,
this text shall determine if there exist significant differences on the density, durability, and
thermal conductivity on Styrofoam without limonene and that with limonene.
Mann – Whitney U test. The test is a non-parametric statistical hypothesis test for
assessing whether two independent samples of observations have equally large values. It is one
of the most well-known non-parametric significance tests. In the context of the research, this test
shall determine if both samples will exhibit significant differences in terms of color and texture
as evaluated by the respondents.
All of the calculations that will be done in the research shall be carried through a software
called MegaStat Excel, an add-on software to Microsoft Excel that processes statistical
calculations.