extraction of unknown

Topics: Hydrochloric acid, Acetic acid, Sodium chloride Pages: 3 (907 words) Published: October 5, 2014

Procedure:
First of all it was carried out an acid-base extraction to separate out the components of the mixture of three unknowns, one neutral, one carboxylic acid and one phenolic. In order to make this extraction it was weight 360 mg of each sample of unknown mixture. Also we labeled a tube called “mixture” where we dissolve the unknown in about 4 mL of ether.

Separation of the organic acid: We added and mixed, and repeated, 2 mL of 1M Sodium Bicarbonate into the ether mixture. Then a pipet is used to separate the lower layer into the tube labeled “unknown acid”. The we used 10 drops of DI water into the mixture tube to wash and then put in the unknown acid tube. Finally the organic acid portion was washed with a few drops of ether to remove any unwanted organic compounds. Separation of the phenol: We added 2 mL of 0.5 M NaOH and we checked that pH was less than 10. Then two layers had mixed and it was separated the lower layer into the pre-weighed test tube for the unknown phenol. Finally we just added about 10 drops of DI water, mixed them and added the aqueous layer to unknown phenol test. Then we added 10 drops of ether to mix two layers and the ether layer was discarded into the waste beaker. At this point, the components of the unknowns were separated but not isolated. The neutral compound remained in the mixture tube, and the others were in their respective acid or phenol tubes.

Isolation of the neutral compound: It is added 2 mL of saturated sodium chloride solution to the mixture of the neutral compound, mixed the layers and removed the aqueous layer to the waste baker. After that it is added anhydrous magnesium sulfate to the test tube until after mixing, the sulfate like snow globe, that means that the solution was dry. To finish the isolation of the neutral compound it was decanted the ether into the test tube labeled unknown neutral, and then it was there until the ether was evaporated. Isolation of the phenol: the unknown phenol...
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