Sunday, August 18, 2019
Acid Base Extraction Essay -- essays research papers
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. Results 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 water               Organic layer=mixture                          aqueous layer=water(clear) Add 10 ml saturated aqueous           Sodium bicarbonate          NaHCO3 dissolves in solution sodium bicarbonate           ... ...sp;      Caffeine salicylate is a Pasteur pipette while the     isolated(white color)          formed. beaker is in the ice bath then vacuum filter. Caffeine beaker:     51.61g           -51.56g                .05g = 50mg % yield = .05g x 100% = 20%      .25g Caffeine salicylate:     17.198g           -17.036g                .062g % yield = .062g x 100% = 25%      .25g Conclusion      According to the HPLC graph that follows, my product was very pure. The actual melting point of caffeine salicylate is 137 degree(C), my product was found to have a melting point of 138 degrees (C). As before, of course this experiment was not done completely error-free, the error is due almost entirely on human error.
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