extraction and crystallization
Discussion:
Extraction and crystallization-
The purpose of this lab was to extract and crystallize compounds in a mixture using acids and bases. 1 gram of the unknown was dissolved into 30 mL of ethyl acetate. The mixture was then transferred to a separatory funnel. Using aqueous solutions of different pH we were able to separate organic acids, bases and neutral compounds from each other. Using three 10 mL portions of HCl, we reacted the HCl with the base in solution. This made it possible to extract the base from the mixture. Organic acids are highly soluble in aqueous NaOH. This reaction that the acid has with the dilute NaOH helps the acid compound be extracted from the mixture. We again used three 10 mL portions this time of NaOH. It is noted that after adding each portion, whether it was HCl or NaOH, the mixture was shaken for about five minutes, this helped the added HCl or NaOH mix thoroughly through out the mixture and react with the acid or base in the mixture. After the separatory funnel stopped being swished around, the mixture in it would separate into two layers, the aqueous and organic layer, the layer extracted for the acid and base would be the bottom aqueous layer. After we gathered and labeled the “acid extract” and the “base extract”, the remaining organic layer in the separatory funnel was gathered and labeled “neutral compound”. At this point the acid, base and neutral compounds had been successfully extracted from the mixture. The neutral compound was put to “dry” with Na2SO4 , once a salt type precipitate formed at the bottom, and was able to stir around without sticking to the bottom the neutral compound would be “dry”. The acid and base extracts were then placed in an ice-water bath. The acidic extract was neutralized with 6M NaOH and a little excess was added in order to make it a bit basic to pH paper. The basic extract was also neutralized with 6M HCl and a little excess was added in order to make it a bit acidic to pH paper.
Extraction and crystallization-
The purpose of this lab was to extract and crystallize compounds in a mixture using acids and bases. 1 gram of the unknown was dissolved into 30 mL of ethyl acetate. The mixture was then transferred to a separatory funnel. Using aqueous solutions of different pH we were able to separate organic acids, bases and neutral compounds from each other. Using three 10 mL portions of HCl, we reacted the HCl with the base in solution. This made it possible to extract the base from the mixture. Organic acids are highly soluble in aqueous NaOH. This reaction that the acid has with the dilute NaOH helps the acid compound be extracted from the mixture. We again used three 10 mL portions this time of NaOH. It is noted that after adding each portion, whether it was HCl or NaOH, the mixture was shaken for about five minutes, this helped the added HCl or NaOH mix thoroughly through out the mixture and react with the acid or base in the mixture. After the separatory funnel stopped being swished around, the mixture in it would separate into two layers, the aqueous and organic layer, the layer extracted for the acid and base would be the bottom aqueous layer. After we gathered and labeled the “acid extract” and the “base extract”, the remaining organic layer in the separatory funnel was gathered and labeled “neutral compound”. At this point the acid, base and neutral compounds had been successfully extracted from the mixture. The neutral compound was put to “dry” with Na2SO4 , once a salt type precipitate formed at the bottom, and was able to stir around without sticking to the bottom the neutral compound would be “dry”. The acid and base extracts were then placed in an ice-water bath. The acidic extract was neutralized with 6M NaOH and a little excess was added in order to make it a bit basic to pH paper. The basic extract was also neutralized with 6M HCl and a little excess was added in order to make it a bit acidic to pH paper.