Extraction Extraction with acid and alkali
EXPERIMENT 13： Extraction: Extraction with acid and alkali
Objective
1. To recover the benzoic acid and p-dichlorobenzene from its mixture from its mixture by using acid-alkali extraction.
2. To determine the percentage recovery and melting point of the recovered benzoic acid and p-dichlorobenzene.
Introduction
Acid-base extraction is a process which purifying the acids and bases from mixtures based on their chemical properties. Acid-base extraction is performed to isolate the compounds and natural products from crude extracts. One of the salt of the mixture should be ionic and tend to be water soluble while the another neutral molecules tend not to be water soluble. Laurence M. Harwood, Christopher J. Moody (13 June 1989) said that the addition of an acid to a mixture of an organic base and acid will result in the acid remaining uncharged, while the base will be protonated. If the organic acid, such as a carboxylic acid is sufficiently strong to self-ionization that can be suppressed by adding the acid. Conversely, the addition of a base to a mixture of an organic acid and base will result in the base remaining uncharged, while the acid is deprotonated to give the corresponding salt. Once again, the self-ionization of a strong base is suppressed by the added base. The acid-base extraction can also be used to separate very-weak acids from stronger acids and very-weak bases from stronger bases as long as the difference of their pKa or pKb constants is large enough.
In this experiment, we would like to carry out the extraction to extract out the benzoic acid p-dichlorobenzene. Benzoic acid is a colourless crystalline solid and the simplest aromatic carboxylic acid. While, the d-dichlorobenzene is an organic compound which is colourless. Its melting point is in the range of 52-54 °C
Experimental procedure
1. 40ml of dichloromethane with contain 1g of p-dichlorobenzene and 1g of benzoic acid are pour into a dry 100ml conical flask.
2. Mix and dissolve the solid
Objective
1. To recover the benzoic acid and p-dichlorobenzene from its mixture from its mixture by using acid-alkali extraction.
2. To determine the percentage recovery and melting point of the recovered benzoic acid and p-dichlorobenzene.
Introduction
Acid-base extraction is a process which purifying the acids and bases from mixtures based on their chemical properties. Acid-base extraction is performed to isolate the compounds and natural products from crude extracts. One of the salt of the mixture should be ionic and tend to be water soluble while the another neutral molecules tend not to be water soluble. Laurence M. Harwood, Christopher J. Moody (13 June 1989) said that the addition of an acid to a mixture of an organic base and acid will result in the acid remaining uncharged, while the base will be protonated. If the organic acid, such as a carboxylic acid is sufficiently strong to self-ionization that can be suppressed by adding the acid. Conversely, the addition of a base to a mixture of an organic acid and base will result in the base remaining uncharged, while the acid is deprotonated to give the corresponding salt. Once again, the self-ionization of a strong base is suppressed by the added base. The acid-base extraction can also be used to separate very-weak acids from stronger acids and very-weak bases from stronger bases as long as the difference of their pKa or pKb constants is large enough.
In this experiment, we would like to carry out the extraction to extract out the benzoic acid p-dichlorobenzene. Benzoic acid is a colourless crystalline solid and the simplest aromatic carboxylic acid. While, the d-dichlorobenzene is an organic compound which is colourless. Its melting point is in the range of 52-54 °C
Experimental procedure
1. 40ml of dichloromethane with contain 1g of p-dichlorobenzene and 1g of benzoic acid are pour into a dry 100ml conical flask.
2. Mix and dissolve the solid