• EugenolSiezing
• Experimental

Materials - Investigation One

The materials needed to complete the experimentation includes a 200.00 g balance, plastic cups, carnauba wax, eugenol from Aldrich, 3 vials with caps, 12 ppt sodium hydroxide solution, distilled water, a beaker, a hot plate, a sonic bath, plastic pipettes, a pH meter, ethanol supplied by Aldrich, palm oil, 333 ppt sodium hydroxide solution, mixing jar, oven, calculator, and a notebook.

Methods and Discussion - Investigation One

The figure below depicts the proposed emulsification to produce microcapsules.

<figure id="lab_emulsification"><title>Emulsification to Produce Microcapsules</title> <mediaobject><imageobject><imagedata fileref="lab_emulsification1.pdf" format="PDF" scale="50"/></imageobject></mediaobject></figure>

The first step to begin the production of a physical microcapsule is to prepare a 12 ppt lye solution, standardize the 12 ppt sodium hydroxide solution, determine the endpoint of eugenol, and then proceed to the production of microcapsules.

To prepare the 12 ppt sodium hydroxide solution, mix 998 g of distilled water with 12.XX g of sodium hydroxide. Standardize the 12 ppt solution with KHP. In our experimentation, we standardized 3 times to get mean and standard deviation for 12 ppt dilute NaOH concentration in mol solute/kg solution (molamity). <xref linkend="R7"/> The average molamity was .3206 mol NaOH/ kg lye solution with a standard deviation of .7 ppt.

Because eugenol is a very weak acid, the endpoint is not sharp.

<figure id="lab_titrationcurve"><title>Simulated Titration Curve for 0.5 g eugenol with .3 m NaOH</title> <mediaobject><imageobject><imagedata fileref="lab_titrationcurve1.pdf" format="PDF" scale="50"/></imageobject></mediaobject></figure>

Therefore, we need to determine the endpoint of 0.5XXX g eugenol. Using the calculation below, the expected endpoint should be reached after 9.5XXX g 12 ppt sodium hydroxide solution is titrated.

<figure id="lab_endpointcalc"><title>Example Calculation for the Endpoint of Eugenol</title> <mediaobject><imageobject><imagedata fileref="lab_endpointcalc1.pdf" format="PDF" scale="50"/></imageobject></mediaobject></figure>

Since gravimetric titrations are being employed, we must know the endpoint pH of 0.5XXX g eugenol. Therefore, titrate 0.5XXX g eugenol with 12 ppt sodium hydroxide solution and record the pH. Add 0.5XXX g eugenol, 50 g of distilled H20, and 50 g of ethanol (to dissolve oil) to a flask. Place a cup of 20 g of 12 ppt NaOH solution on a balance and tare balance. Remove NaOH from cup to flask and record pH at each interval. Pay close attention to pH from 9-11 grams because we want to know the pH when 9.5XXX g of sodium hydroxide have been added to the flask! From our results, it was determined the pH for the endpoint of 0.5XXX g of eugenol is 12.46 with a standard deviation of .005. We used our results to complete an interpolation. At a pH of 12.46 the average amount of 12 ppt sodium hydroxide was interpolated to be 9.55 g 12 ppt sodium hydroxide.

<figure id="lab_curve"><title>Actual Titration Curve for 0.5 g eugenol with .3 m NaOH</title> <mediaobject><imageobject><imagedata fileref="lab_curve1.pdf" format="PDF" scale="50"/></imageobject></mediaobject></figure>

Knowing the pH for the endpoint of 0.5 g of eugenol we can create our first emulsion using microencapsulation. The first step is to weigh out 0.50XX g of eugenol into a vial. Next, add 2.00 g of carnauba wax to the vial. Then, add 4.00 g of distilled water the vial. Add 1 drop of 12 ppt lye to the vial; in this case one drop is equivalent to 0.10 g. Place the cap on the vial and add to a hot water bath to melt the mixture. Once the mixture is fully liquefied shake the vial to create and emulsion. The emulsion should appear creamy yellow. After the vial has cooled add to the sonic bath. Remove the vial from the sonic bath. Next, add a 50/50 solution of ethanol and distilled water (50 g / 50 g) into a beaker. Add the emulsion mixture (microcapsules) to the plastic cup. Use gravimetric titrations to titrate the emulsion to a pH of 12.46 with the 12 ppt NaOH solution. Once a pH of 12.46 has been reached use the corresponding amount of 12 ppt lye solution to determine the amount of free eugenol.

<figure id="lab_freecalc"><title>Sample Calculation of % Free Eugenol</title> <mediaobject><imageobject><imagedata fileref="lab_freecalc1.pdf" format="PDF" scale="50"/></imageobject></mediaobject></figure>

From 3 trials, we found that there was an average of about 32.3% <quote>free eugenol</quote> +/- 5.5%. In other words about 70% of the eugenol was protected by the wax.

Next, we wanted to test out the microcapsules in real soap making conditions. Three different 100 g palm oil bars of soap were produced. Add 100 g Palm Oil, 42 g 333 ppt NaOH, and our emulsion to mixing jar. Seizing should not occur! Mix until trace is reached. Pour mixture in mold, place in oven for 4 hours at 150°C. Remove from oven and weigh bar of soap. Next, add 100 g Palm Oil, 42 g 333 ppt NaOH, and 1 g eugenol to mixing jar. Mix until trace is reached. Pour mixture in mold, place in oven for 4 hours at 150°C. Remove from oven and weigh bar of soap. Lastly, add 100 g Palm Oil, 42 g 333 ppt NaOH to mixing jar. Mix until trace is reached. Pour mixture in mold, place in oven for 4 hours at 150°C. Remove from oven and weigh bar of soap. From our results, we calculated that the bar of palm oil soap with the microcapsules weighed 84.9% of original weight, the bar of palm oil soap without any form of scent weighed 87.5% of original weight, and the bar of palm oil soap with eugenol added directly without protection weighed 73.1% of original weight.<xref linkend="T1"/>

<table id="T1"><title>100 g Palm Oil Soap Bars</title>

</table>

<bibliomixed id="R7">Ramette, Richard W. <citetitle>In Support of Weigh Titration Techniques</citetitle>, Chemical Education Today: 81:12, 2004.</bibliomixed>

Materials - Investigation Two

Saponification Value Determination

A 200 g balance, palm oil, 6% ethanolic KOH solution, 6% methanolic KOH solution, 500.0 ppt citric acid solution, six clean 500-mL Erlenmeyer flasks (labeled Blank A, Blank B, Blank C, Soap A, Soap B, Soap C), three watch glasses, three plastic weighing cups (labeled Oil, Acid, and Base), three pipets (labeled Oil, Acid, and Base), and a soap oven.

Residual Total Alkali Determination

A 200 g balance, sample of soaps, distilled wather, 500-mL Erlenmery flask, a soap oven, a knife, 100.0 ppt citric acid standard, two plastic cups (labeled Soap and Acid), a pipet (labeled Acid), 1% Phenolphthalein solution.

Methods and Discussion - Investigation Two

Saponification Value Determination

The first part of this experiment involved determining whether to use an ethanolic KOH solution or a methanolic KOH solution. Therefore, two experiments were completed: the AOCS Recommended Practice Cd 3c-91 - Saponification Value Modified Method Using Methanol and the AOCS Official Method Cd 3-25 Saponification Value experiment. It was found that the AOCS Official Method Cd 3-25 Saponification Value experiment should be the preferred choice of procedure. As for the ease of each each experiment, the ethanol and methanol techniques are very similar. In addition, one experiment does not take any longer than the other experiment. As for the cost of materials to complete each experiment, methanol is much higher in cost than ethanol. In fact, methanol usually cost about double compared to ethanol. In addition, ethanol can be purchased from Wal-Mart for about $7.00 a liter. Lastly, using the methanol technique does not always guarantee the same results when an experiment is repeated whereas, the ethanol technique is reliable for reproduction. Therefore, all saponification values were determined in our experimentation using 6% ethanolic KOH.

A number of SAP determinations were completed using the following technique: first, the oven was preheated to 170 degrees Farenheight. Using the base weighing cup and base pipet, 100.00 g of the 6% ethanolic KOH solution was synthetically weighed into the Blank A flask. Identical amounts of ethanolic KOH solution was weighed into Blank B, Blank C, Soap A, Soap B, and Soap C flasks. Using the oil cup and the oil pipet, 20.00 g of palm oil was weighed into Soap A flask. Identical portions of oil were weighed to Soap B and Soap C flasks. All soap flasks were placed into the soap oven for 1 hour to ensure complete soaponification. Add two or three drops of indicator to each Blank flask. While the soaps were cooking, all Blank flasks were titrated with 500.0 ppt citric acid using the gravimetric titration technique. After an hour, the soap flasks were removed from the oven. Immediately add two or three drops of indication to each soap flask and titrate with 500 ppt citric acid solution. From these titrations, SAP values were calculated using the following calculation:

? g NaOH = 312.3 (YY.YY - ZZ.ZZ / 20.XX) g NaOH, where 20.XX is the exact amount of oil used for each Soap flask, YY.YY is the endpoint for the blank flask, and ZZ.ZZ is the endpoint for the Soap flask.

For our palm oil, our SAP value was determined to be 145.78 +/- .39 g or 145.78 +/- .39 ppt. These values were used to create a number of soaps, which an RTA value was then determined. See the next experiment for results.

Residual Total Alkali Determination

A residual total alkali determination was conducted on soaps produced using the saponification value calculated in the previous experiment. This experiment began by preheating the oven to 200 degrees Fahrenheit. The soap was placed in a cup onto the balance and balance was tarred. The knife was used to carefully shave more than 10.00 grams into the cup. With the Soap cup still on the balance, the balanced was once again tarred. The contents of the soap cup were poured into the Erlenmeyer flask. The amount of soap transferred was recorded. About 250 mL of distilled water was added to the soap flask. The soap was placed into the oven for about 1 hour. The soap was removed from the oven and allowed to cool to room temperature. Two or three drops of indicator were added to the flask. 100.0 ppt citric acid standard was used to titrate by the gravimetric titration technique.

The RTA Value of each soap was calculated and the results are as follows: ? g NaOH = 62.47 (0.YY/10.XX) g NaOH, where 0.YY is the endpoint and 10.XX is the amount of soap used.

<table id="T3"><title>RTA Calculations of Palm Oil Soap Bars</title>

</table>