Trans-Cinnamic Acid Results
Yield Data
The reaction of 0.139 grams of trans-cinnamic acid, 0.8 mL of glacial acetic acid, and 1.0 mL of 1.0 M of Bromine in acetic acid was recrystallized to form a solid, clear, crystal- like product. The melting was taken from the recrystallized product to determine what had been obtained. The melting point was found to be 130.5°C-133.7°C. Concluding that the product formed from the addition of bromine was a mixture of the erythro-2, 3-dibromo-3-phenylpropanoic acid, which has a known melting point of 204°C, and threo-2,3-dibromo-3-phenylpropanoic acid, which has a known melting point of 95°C. Meaning the recrystallized product was a racemic mixture. I obtained .204 grams of the racemic mixture product, meaning my percent yield is 66.23%.
Percent yield= experimental yield (the amount obtained) = 0.204 X 100= 66.23% …show more content…
The melting point range is less than five degrees apart, meaning there were not many impurities in the final product. The H’ NMR of the starting material, trans cinnamic acid, is almost the exact same as the he H’ NMR of the final product. The only difference was the extra signal around 5 ppm. The reason behind the extra signal is the addition of the Bromine to the trans-cinnamic acid.
The H’ NMR matched my predictions almost exactly, meaning the product is what was suppose to be obtained. All of the signals (b.c.e.d.f) were where they were projected- except for signal a. Signal a was the projection for the hydrogen in the carboxylic acid. I did not see a signal in the projected region, which was 9.5-10.1. The cause of the signal being missing may be because there is still water present in the mixture, or trans-cinnamic acid in the solid product that was formed. (see attached paper for viewing of
The reaction of 0.139 grams of trans-cinnamic acid, 0.8 mL of glacial acetic acid, and 1.0 mL of 1.0 M of Bromine in acetic acid was recrystallized to form a solid, clear, crystal- like product. The melting was taken from the recrystallized product to determine what had been obtained. The melting point was found to be 130.5°C-133.7°C. Concluding that the product formed from the addition of bromine was a mixture of the erythro-2, 3-dibromo-3-phenylpropanoic acid, which has a known melting point of 204°C, and threo-2,3-dibromo-3-phenylpropanoic acid, which has a known melting point of 95°C. Meaning the recrystallized product was a racemic mixture. I obtained .204 grams of the racemic mixture product, meaning my percent yield is 66.23%.
Percent yield= experimental yield (the amount obtained) = 0.204 X 100= 66.23% …show more content…
The melting point range is less than five degrees apart, meaning there were not many impurities in the final product. The H’ NMR of the starting material, trans cinnamic acid, is almost the exact same as the he H’ NMR of the final product. The only difference was the extra signal around 5 ppm. The reason behind the extra signal is the addition of the Bromine to the trans-cinnamic acid.
The H’ NMR matched my predictions almost exactly, meaning the product is what was suppose to be obtained. All of the signals (b.c.e.d.f) were where they were projected- except for signal a. Signal a was the projection for the hydrogen in the carboxylic acid. I did not see a signal in the projected region, which was 9.5-10.1. The cause of the signal being missing may be because there is still water present in the mixture, or trans-cinnamic acid in the solid product that was formed. (see attached paper for viewing of