Grignard Synthesis Lab Report
Grignard Synthesis of Tirphenylmethanol
David Szuminsky
Organic Chemistry Lab II
Shaopeng Zhang
Monday 1PM
2/10/14 & 2/24/14
- Abstract A sample of triphenylmethanol was prepared using Grignard synthesis techniques. Reflux was used in order to speed up the reaction and the final product was purified using recrystallization methods. The percent recovery and percent yield were 80.46% and 47.526%, respectively. A melting point range of 85-87oC was obtained from the purified product.
- Introduction A Grignard reaction adds an alkyl-magnesium halide to an aldehyde or ketone carbonyl carbon. The alkyl-magnesium halide is known as the Grignard reagent. The carbon bonded to the magnesium …show more content…
The reaction mixture initially was a brown color which then turned a milky white color with the addition of bromobenzene and ether. The mixture turned back to a brown color with the addition of the remaining bromobenzene and ether added at a dropwise rate. The reaction vessel became warm at this point. The mixture then turned a reddish, pink color with the addition of 9.1g benzophenone in 100mL anhydrous ethyl ether. During the reflux the reaction mixture first turned a “pepto bismal” pink color then became a thick white liquid/solid. When the sulfuric acid was added the solution turned a yellow …show more content…
The first peak at 3058.86cm-1 indicates an alcohol functional group present in the compound. The other two peaks correspond to the peaks of aromatic carbon-carbon double bonds. The proton NMR acquired indicates two different hydrogen’s present in the compound which correctly corresponds to triphenylmethanol. The peak at about 7.4ppm is the peak for the aromatic hydrogens on the three phenyl rings. The peak at about 3.6ppm is the hydrogen part of the hydroxyl group. The carbon NMR acquired also corroborates the conclusion that the final compound is triphenylmethanol. The peak at about 82ppm corresponds with the carbon bonded to the alcohol functional group. The other four peaks correspond respectively to the carbons of the phenyl groups as indicated on the attached carbon NMR. The purified sample provided a melting point range of 85-87oC which is rather far off of the desired theoretical value of about 160oC. This large skew on the melting point range is most likely due to impurity being present in the final product producing a melting point depression. A Grignard synthesis must be initially prepared in the absence of water in order to ensure the highest yield possible because water will quench the reaction ultimately affecting the yield. This is one of several sources of error that could have been encountered in this experiment. During the
David Szuminsky
Organic Chemistry Lab II
Shaopeng Zhang
Monday 1PM
2/10/14 & 2/24/14
- Abstract A sample of triphenylmethanol was prepared using Grignard synthesis techniques. Reflux was used in order to speed up the reaction and the final product was purified using recrystallization methods. The percent recovery and percent yield were 80.46% and 47.526%, respectively. A melting point range of 85-87oC was obtained from the purified product.
- Introduction A Grignard reaction adds an alkyl-magnesium halide to an aldehyde or ketone carbonyl carbon. The alkyl-magnesium halide is known as the Grignard reagent. The carbon bonded to the magnesium …show more content…
The reaction mixture initially was a brown color which then turned a milky white color with the addition of bromobenzene and ether. The mixture turned back to a brown color with the addition of the remaining bromobenzene and ether added at a dropwise rate. The reaction vessel became warm at this point. The mixture then turned a reddish, pink color with the addition of 9.1g benzophenone in 100mL anhydrous ethyl ether. During the reflux the reaction mixture first turned a “pepto bismal” pink color then became a thick white liquid/solid. When the sulfuric acid was added the solution turned a yellow …show more content…
The first peak at 3058.86cm-1 indicates an alcohol functional group present in the compound. The other two peaks correspond to the peaks of aromatic carbon-carbon double bonds. The proton NMR acquired indicates two different hydrogen’s present in the compound which correctly corresponds to triphenylmethanol. The peak at about 7.4ppm is the peak for the aromatic hydrogens on the three phenyl rings. The peak at about 3.6ppm is the hydrogen part of the hydroxyl group. The carbon NMR acquired also corroborates the conclusion that the final compound is triphenylmethanol. The peak at about 82ppm corresponds with the carbon bonded to the alcohol functional group. The other four peaks correspond respectively to the carbons of the phenyl groups as indicated on the attached carbon NMR. The purified sample provided a melting point range of 85-87oC which is rather far off of the desired theoretical value of about 160oC. This large skew on the melting point range is most likely due to impurity being present in the final product producing a melting point depression. A Grignard synthesis must be initially prepared in the absence of water in order to ensure the highest yield possible because water will quench the reaction ultimately affecting the yield. This is one of several sources of error that could have been encountered in this experiment. During the