Exp. 3 Euclyptus Oil PDF

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Exp #3 Section AB1 10/14/2012 Identification of a Conjugated Diene in Eucalyptus Oil Introduction: In this lab the components of Eucalyptus dives oil were isolated then identified. The components were separated by using a Diels-Alder reaction to form a solid that was purified by recrystallization. Reaction/ Table of Reagents

Potential Products:

allo-ocimene

α-terpinene β-myrcene

Mechanisms-

C4H6 + C4H2O3  C8H8O3 C4H6 + C10H18O  C14H24O Table of Reagents

α-phellandrene

Eucalyptol Petroleum Ether Acetone Maleic Anhydride Diethyl Ether

MW (g/mol) 154.249 N/A 58.08 98.1

MP(ºC) 1.5 N/A -95-(-93) 53

Density (g/ml) 0.9225 Vapor: 3.9 0.791 N/A

Formula C10H8O C6H6 C3H6O C4H2O3

74.1

-116

0.714

C4H10O

Theoretical Yield: 98.057 4.004 g of Eucalyptus dives ×

g Maleic Anhydride mol =0.6340 g 136.234 Diene

Experimental Procedure: A GC chromatogram of Eucalyptus dives oil was given and used to find the theoretical yield which came out to be 0.6340g of maleic anhydride. 4.004g of eucalyptus dives oil was poured in to 10 mL of petroleum ether in a 25 ml round bottom flask. The calculated amount of maleic anhydride was poured into the same round bottom flask. A condenser was set up with the round bottom flask. The round bottom flask was heated for 62 minutes. When the reflux was done the solution was cooled to room temperature. No crystals were forming so a stirring rod was used to scratch the sides of the flask, and some crystals started to form. Once crystallization was completed, the flask was cooled in an ice bath and the crystals were collected by vacuum filtration. The remaining crystals in the flask were washed out with 10 mL of cold petroleum ether. The crude product collected was weighed to be 0.228g before recrystallizing with acetone and water. Once the crude product was recrystallized, the product was vacuum filtered and washed with cold water. About 0.333g of product was collected. Then the measuring point was found along with the IR spectrum. Results: Heating Reflux at 150ºC for 62 minutes. Crude Product:

Filter Paper without Crude Product: 0.203g Filter Paper with Crude Product: 0.431g Crude Product: 0.228g Recrystallized Product: Percent Yield: 0.333 g ×100 %=52.52 % 0.6340 g Experimental Yield 0.333g

Percent Yield 52.52%

Melting Point 120.1-126.9ºC

Filter Paper: 0.205g Filter Paper with Product: 0.538g Mass of Product: 0.333g Melting Point Range: 120.1ºC-126.9ºC IR Summary Bond Type C-H Phenyl C-H Alkane Cyclopentanone C-O

IR Spectrum 3055.16 2963.93 1777.75 1265.47

Discussion: From the experimental data collected for the melting point of the final product. The diene melting point range came out to be 120.1ºC-126.9ºC. This was very close to the melting point of α- phellandrene. The melting point for α- phellandrene is 127ºC. This data collected helped the most with identifying which diene was used. Also from the experimental yield was calculated to be 0.333g. The theoretical yield came out to be 0.6340g of the percent yield was 52.52%. I think

that I may have refluxed the solution for too long along with the temperature being too high. The suggested temperature at which it was suppose to reflux was 70º-75ºC. Because of the higher temperature and longer reflux time, some of the vapors may have escaped from the reflux apparatus. Also during the recrystallization there may have been poor quality in transferring the crude product into the vacuum filter. The loss of the product can certainly affect the final mass of the product. The purity of the final product based on the melting point seems to be very pure due to the fact that the melting point range just barely missed the theoretical melting point. The IR spectrum shows most of the bonds represented but there are some outliers on the IR.

Post Lab Questions: 1. A couple big similarities are the peak at around 1770 cm-1 and 3100 cm-1. Some differences include the impurities that are found on my IR spectrum. There is an impurity on my IR at 2963.93 cm-1. And the peaks after 1800 are much longer on my graph than the maleic acid graph. 2. The stirring rod was dipped in to and used to scratch the side of the flask in order to agitate the molecules to clump and precipitate. 3. a. If the calculated amount of maleic anhydride is based on the total mass of the oil, nothing would be changed; it would just be the same to this experiment. b. If the reaction flask was not dry the product formed would not be a pure substance. It would have traces of what was left in the flask. c. If no water is running through the condenser then the vapors will not condense and reflux back into the reaction flask. It would create more pressure and some of the vapors may escape and the product may leave as well giving a low percent yield. d. A lower melting point would be recorded due to the fact that the impurities will get in between the crystalline structure bonds and make it easier for the bond to break.

e. Washing the crude crystals with hot petroleum ether would dissolve some of the crystals as it was being washed. Therefore some of the final product would be lost and lower the percent yield....