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Jan 9, 2024

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NAME: Qiutong Huang EXPERIMENT 6 FISCHER ESTERIFICATION Summary of Points for Experiment 6: Item Possible Points Actual Points PRE-LAB 2 NOTEBOOK: Purpose/Table of Reagents 2 Corrections 2 Blank Spaces 2 Signatures 2 TLC’s N/A Coherent 2 Conclusions (absent here) 1 Sub-Total = 13 multiply Sub-Total x 1= 13 REPORT: Introduction 2 Data and Calculations 59 Unknown ID 7 Data Analysis / Conclusions 5 Sub-Total = 73 TOTAL 86 POINT DEDUCTIONS: minus any page over 7 (0) minus for late reports (0) minus for TA points (0) minus for missing attachments (0) TOTAL POINTS 86 ADJUSTED TOTAL POINTS = Total Points x 60/86 60

INTRODUCTION (2 points) This experiment produce fischer ester through reaction between unknown alcohol and excess carboxylic acid using a reflux setup. The ester was characterized by Infrared Spectroscopy, Gas Chromatography, and boiling point analysis. IR was used to identify specific functional groups in compounds through vibrational bonding. Based on the graph of percent transmission versus the wavenumber, the functional group presented in ester could be verified. DATA AND CALCULATIONS GC DATA: RETENTION TIME FOR SYNTHESIZED ESTER: 0.829 (2 points) RETENTION TIME FOR REFERENCE STANDARD WITH CLOSEST RETENTION TIME: 0.853 DOES CO-INJECTION SHOW SINGLE GC ESTER PEAK? Yes BASED ON THIS GC DATA, THE PRESUMED IDENTITY OF SYNTHESIZED ESTER (FROM TABLE 1) IS: NAME: Isoamyl acetate SUPPORT FOR THIS ID IS FROM BP AND IR DATA: MEASURED BP of PRODUCT ESTER: N/A (2 points) LITERATURE BP : 142 / 756 mmHg (2 points) LITERATURE SOURCE of BP: www.sigmaaldrich.com (1 point) PRODUCT ESTER: YOUR DATA (6 points; 0.5 points per entry) Peak is due to the bond shown: Absorbance (cm -1 ) Strength (s,m,w) Shape (s,br) Peak is due to this bond motion: O-H absence absence absence O-H stretching C=O 1741.55 s s C=O stretching C-O 1229.65 m s C-O bending

PRODUCT ESTER: LITERATURE DATA (6 points; 0.5 points per entry) Peak is due to the bond shown: Absorbance (cm -1 ) Strength (s,m,w) Shape (s,br) Peak is due to this bond motion: O-H absence absence absence O-H stretching C=O 1800-1700 s s C=O stretching C-O 1300-1200 m s C-O bending Source of literature data : https://www.chemicalbook.com/SpectrumEN_123-92-2_IR2.htm (1 point) ACETIC ACID: LITERATURE DATA (6 points; 0.5 points per entry) Peak is due to the bond shown: Absorbance (cm -1 ) Strength (s,m,w) Shape (s,br) Peak is due to this bond motion: O-H 3300-2500 m br O-H stretching C=O 1800-1700 s s C=O stretching C-O 1300-1200 m s C-O bending Source of literature data : https://www.chemicalbook.com/SpectrumEN_64-19-7_IR2.htm (1 point) ALCOHOL: LITERATURE DATA (6 points; 0.5 points per entry) Peak is due to the bond shown: Absorbance (cm -1 ) Strength (s,m,w) Shape (s,br) Peak is due to this bond motion: O-H 3500-3100 m br O-H stretching C=O absence absence absence C=O stretching C-O 1100-1000 m s C-O bending Source of literature data :https://www.chemicalbook.com/SpectrumEN_123-51-3_IR1.htm (1 point) FINAL CONFIRMED IDENTITY OF SYNTHESIZED ESTER (FROM TABLE 1): UNKNOWN ALCOHOL NUMBER: #411 UNKNOWN ESTER ID (name): Isopentyl acetate UNKNOWN STRUCTURE: (7 points) YIELD CALCULATION Balanced equation for Fischer esterification:

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acetic acid alcohol H 2 SO 4 ester water Fill in the table below using the appropriate data for your alcohol: (12 points; 0.5 points per correct entry) Acetic Acid Alcohol H 2 SO 4 Ester* Water H 2 SO 4 volume 1.5 mL 0.5 mL 1 drop 0.682 mL 0.0827 mL 1 drop density** 1.049 g/mL 0.809 g/mL N/A 0.876 g/mL 1.00 g/mL N/A grams 1.5735 g 0.4045 g N/A 0.5975 g 0.0827 g N/A mol wt 60.05 88.15 N/A 130.18 18.02 N/A moles 0.0262 0.00459 N/A 0.00459 0.00459 N/A equivalent s 5.7 1.0 catalyst 1.0 1.0 catalyst * these are the theoretical amounts (assuming 100% conversion) ** literature source for density values: www.chemicalbook.com/ProductChemicalProperties (1 point) Theoretical yield of ester ( in moles ; show calculations; be sure to determine and utilize the limiting reagent for your calculation): Mol Alcohol = m/MW = 0.4045g/88.15 = 0.00459 mol Mol acetic acid = 1.5735g/60.05 = 0.0262 mol > 0.00459 mol; Alcohol is limiting reagent Theoretical yield of ester in moles = mol alcohol = 0.00459 mol THEORETICAL YIELD: 0.00459 mol (7 points) Actual yield of ester ( as a percentage ): actual mol/ theoretical mol *100%= (0.6858g/130.18)mol/ 0.00459 mol *100% = 115% % YIELD: 115% (7 points)

DATA ANALYSIS AND CONCLUSIONS (5 points) Based on the IR spectrum of the Fischer product, the strong characteristic peak at 1741.55 cm -1 verified the C=O stretching of this ester and the peak at 1229.65 cm -1 verified the C-O stretching. On the other hand, the IR spectrum of the starting material (unknown alcohol #411) had broad peak at 3323.68 cm -1 indicating its O-H stretching and the sharp peak at 1056.58 cm -1 verified the C-O stretching of the alcohol. Comparing these two spectra, the conversion from alcohol to ester through Fischer esterification was pretty successful. The IR technique can efficiently identify the characteristic functional groups of unknown compound but it was not so effective in determining the purity of compounds. Mixed melting point and TLC plates would be better at finding purity of unknowns. ATTACHMENTS: GC TRACE Attach your GC trace to this report You should have a total of 2 GC traces for your product ester from the Fischer esterification (product ester alone and co-injection with known reference). First, record the GC instrument parameters below: loss of 2 points for each missing GC parameter GC Parameters: Column packing material: 10% SE30 LIQUID PHASE ON CHROMOSORB WHP SOLID SUPPORT, 80/100 MESH Mobile phase (name of gas): Helium, flow rate 30mL/min Injector temperature: 150 ℃ Column temperature: 130 ℃ Detector temperature: 180 ℃ ATTACHMENTS: IR SPECTRUM

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