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Unformatted text preview: recrystallization. After
allowing the vial to recrystallize on ice for 10 minutes, a glass stirring rod was used to scratch
the inside of the conical vial and a white slush liquid appeared while crystals formed. The
solution containing the crystals was then put through the vacuum filter. The vial and crystals
were rinsed with 1 mL of cold petroleum ether. White crystals resulted with a brown tint due to
the heating of the boiling stones. The crystals were then emptied into a pre-weighed aluminum
The tray weighed 1.369 grams without the crystals and 1.416 grams with the crystals.
The mass of the crystals was 0.047 grams when weighed the first time and a week later they
were reweighed and totaled 0.046 grams. The solid crystalline product is cyclohex-4-ene-1,2dicarboxylic anhydride and the melting point was also measured and determined to be 92.794.2oC. The limiting reagent was determined to be maleic anhydride at 9.68x10-4 mols, this was
then multiplied by 152.15 g/mol, the molecular weight of cyclohex-4-ene-1,2-dicarboxylic
anhydride, to give the theoretical yield of 0.147 grams cyclohex-4-ene-1,2-dicarboxylic
anhydride. The mass of the dried crystals, 0.046 g was then divided by the theoretical yield of
0.147 g and multiplied by 100 to give the percent yield of the product which was approximately
31.3%. All physical data can be seen in Data Table 2 and calculations are below.
Figure 3: Reflux Apparatus4 Calculations and Data:
Maleic Anhydride: (0.095 g) / (98.06 g/mol) = 9.68 x 10-4 mol = limiting reagent
Butadiene: (0.207 g) / (118.11 g/mol) = 1.75 x 10-3 mol
Theoretical Yield: 9.68 x 10-4 mol x 152.15 g/mol C8H8O3 = 0.147 g Cyclohex-4-ene-1,2dicarboxylic Anhydride
Percent Yield: (0.046 g obtained product) / (0.147 g) x 100 = 31.3% Data Table 2:
Compound Mass Crystals Week 1 Cyclohex-4-ene-1,2dicarboxylic
0.047 g Mass Crystals Week 2 0.046 g Melting Point 1 92.7-94.2 oC Melting Point 2 93.2-94.3 oC Literature Melting
Percent Yield 103-104 oC
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