Acid Base Extraction

Topics: Acid, Solvent, Acetic acid Pages: 8 (1625 words) Published: October 8, 1999
Acid Base Extraction

The purpose of this laboratory assignment was two-fold, first, we were to demonstrate the extraction of acids and bases, finally, determining what unknowns were present. Second, we were to extract caffeine from tea. These two assignment will be documented in two separate entities.

Introduction: Acid/base extraction involves carrying out simple acid/base reactions in order to separate strong organic acids, weak organic acids neutral organic compounds and basic organic substances. The procedure for this laboratory assignment are on the following pages.

3) Separation of Carboxylic Acid, a Phenol and a Neutral Substance

The purpose of this acid/base extraction is to separate a mixture of equal parts of benzoic acid(strong acid) and 2-naphthanol(weak base) and 1,4- dimethoxybenzene(neutral) by extracting from tert-butylmethyl ether(very volatile).The goal of this experiment was to identify the three components in the mixture and to determine the percent recovery of each from the mixture.

4) Separation of a Neutral and Basic Substance

A mixture of equal parts of a neutral substance containing either naphthalene or benzoin and a basic substance containing either 4-chloroaniline or ethyl 4-aminobenzoate were to be separated by extraction from an ether solution. Once the separation took place, and crystallization was carried out, it became possible to determine what components were in the unknown mixture, by means of a melting point determination.


Procedure Observations Inference

Dissolve 3.05g Phenol Mixture was a golden-Neutral acid in 30ml brown/yellow color t-butyl methyl ether in Erlenmeyer flask and transfer mixture to 125ml separatory funnel using little ether to complete the transfer

Add 10 ml of waterOrganic layer=mixture
aqueous layer=water(clear)

Add 10 ml saturated aqueous Sodium bicarbonateNaHCO3
dissolves in solution sodium bicarbonate
water. to funnel and mix cautiously with stopper on

Vent liberated carbonCarbon dioxide gas dioxide and shake the mixturewas released three times thoroughly with frequent venting of the funnel

Allow layers to separateLayer = H2O +NaHCO3 completely and draw off lower layer into 50ml Erlenmeyer flask 1

Add 10ml of 1.5 aqueous NaOHFlask 2 = H2O + NaHCO3 (5ml of 3M and 5ml H2O) to separatory funnel, shake mixture, allow layers to separate and draw off lower layer into a 25ml Erlenmeyer flask 2. Add additional 5ml of water to funnel, shake as before

Add 15 ml NaCl to funnel. ShakeBottom layer is white andNaCl was added to the mixture and allow layers to separate gooey. wash the ether and draw off lower layer, which is
layer and to remove discarded organic substances
NaOH and
NaHCO3 Pour ether layer into 50ml Erlenmeyer flask from the top of the separatory funnel (not allowing any water droplets to be transferred) Flask 3

Add anhydrous NaSO4 to ether extract until it no longer clumps together and set it aside

Acidify contents of flask 2Litmus went from
Acidification was now by dropwise addition of blue to pink. Flask complete concentrated HCl while 2 = creamy color testing with litmus paper and cool in ice

Acidify contents of flask 1Litmus went from
Acidification was now by adding HCl dropwiseblue to pink. Flask complete while testing with litmus2 = white solution paper and cool in ice

Decant ether from flask 3 into a tared flask

Boil ether with boiling chips

Do a vacuum filtration and Solution turns to a
Crystallization is now recrystallize ether by dissolving itsolid. complete in 5ml, taking out boiling chips, adding drops of Ligroin until the...
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