E4

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University of California, San Diego *

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43A

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Chemistry

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Jan 9, 2024

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NAME: ___Qiutong Huang___________ EXPERIMENT 4 CHROMATOGRAPHY Summary of Points for Experiment 4: Item Possible Points Actual Points PRE-LAB 2 NOTEBOOK: Purpose/Table of Reagents 2 Corrections 2 Blank Spaces 2 Signatures 2 TLC’s (4x8 pts) 32 Coherent 2 Conclusions (absent here) 1 Sub-Total = 45 multiply Sub-Total x 2= 90 REPORT: Introduction 2 Data and Calculations 34 ID Analgesic 5 ID Column Components 6 Data Analysis / Conclusions 5 Sub-Total = 52 TOTAL 142 POINT DEDUCTIONS: minus any page over 4 (0) minus for late reports (0) minus for TA points (0) TOTAL POINTS 142 ADJUSTED TOTAL POINTS = Total Points x 50/142 50

INTRODUCTION (2 points) This experiment aimed to use thin layer chromatography to identify compounds through co-spotting and isolate the organic compounds in the unknown mixture through column chromatography. DATA AND CALCULATIONS PART A Below, draw the TLC that you ran of the two acetophenone isomers. (8 points) Rf for para-hydroxyacetophenone: 0.5 Rf for ortho-hydroxyacetophenone: 0.83 PART B Below, draw the TLC that you ran of your unknown analgesic versus the known standards. (8 points) 75% EtOAc/PE UV visualization Silica gel 30% EtOAc/PE UV Visualization Silica gel co P O Unk ac ib ca aa E2

Below, draw the TLC that you ran of your unknown analgesic co-spotting with the known standard. (8 points) 75% EtOAc/PE UV visualization Silica gel ANALGESIC UNKNOWN ID UNKNOWN #: ____300_______ IDENTITY OF UNKNOWN ANALGESIC: __acetaminophen and caffeine___ (5 points) VERIFICATION of EXPERIMENT 3 CAFFEINE ID Rf of authentic caffeine: _____0.077______ (1 point) Rf of sublimed material from E-2: ________0.077_______ (1 point) PART C Below, draw the TLC of the three component mixture that you separated via column chromatography. Draw the TLC for the beginning mixture and all fractions (similar to the TLC depicted on page 7 of the Experiment 4 document). (8 points) Fill out the Following Table with Data From Your Notebook Unk ac ca co spot Unk f af 9f 1 2 3 4 5 6 7 8 15% MtBE/PE UV Visualization

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Order of Elution From Column Rf Identity of Compound First 0.82 ferrocene Second 0.73 9-fluorenone Third 0.27 acerylferrocene MAX POSSIBLE: 6 points DATA ANALYSIS AND CONCLUSIONS (5 points) In part A, the co-spot for both isomers enabled us to practice proper use of TLC analysis. In part B, the unknown mixture #300 was identified as a mixture of acetaminophen and caffeine based on the co-spotting TLC plate using 75% of EtOAc/PE as solvent. The Rf values for sublimated caffeine from previous lab E2 was 0.077 which matched with the Rf value for authentic caffeine. This proved that the extraction and purification of caffeine in E2 was successful. In part C, the column chromatography indicated the order of elution from column started from ferrocene to 9-fluorenone and ended with acerylferrocene.