ISOPENTYL ACETATE SYNTHESIS Post-Lab Submitted by Vivian M. Chan Teaching Fellow: Long Nguyen Calculations and Conclusion: In this lab, isopentyl acetate was synthesized by combining isopentyl alcohol and acetic acid. In this reaction, molecules were joined through the intermolecular elimination of water. A method of liquid extraction was used to wash the product with water, Sodium Bicarbonate and Sodium Chloride. Simple Distillation was used to retrieve a more pure product. The final crude product yield was 0.91g and the pure product yield was 0.36g.
The mobile phase used in this particular experiment was Methanol and 0.1M sodium dihydrogen phosphate at a ratio of 30:70 and a pH of 4.5, slightly acidic. The stationary phase is the silica based particles packed within the column. The key characteristic of HPLC is the sheer pressure it works under. In fact HPLC is often referred to as high pressure liquid chromatography. The pressure at which the machine used in this investigation works is around 1900psi (pounds per square inch) which is the equivalent of 129.29 atmospheres!
Dileepa Galagedera 02/14/14 Chemistry 106LB – 03 Ms. C. Chrissian Lab 2 – A Library for Chemists * Part I - Warm Up Questions; * Graph #1: a plot made from an equation. * Graph #2: a plot made from supplied data and an equation derived from the plot. * Graph #3: A plot made from an equation; If the value of y is 0.12, the value of x would be (0.12 + 0.01)/ 0.008, or 16.25. * Graph #4 – A straight line plot generated from a made up equation. * Graph #5 – An equation generated from a made up straight line plot.
Determining the Concentration of a Solution: Beer’s Law Purpose: The purpose of this lab was to measure absorbance value of standard solutions. And to find the relationship between absorbance and concentration. Then determine the concentration and the formula of the unknown CO(NO3)2*nH2O solution. Introduction: The reason we conducted this experiment was to determine the concentration and formula of an unknown solution. We used a calorimeter to monitor the light received by the photocell to determine the absorbance of different concentrations of cobalt chloride hexahydrate.
This may have been low due to not all of the condensed product being removed from the Hickman still, some product being lost during transfer of the product from the reaction tube into the Hickman still, or the loss of some product due to evaporation during distillation. Infrared spectrum analysis of the product indicated that the product was isopentyl acetate, as expected, and thus that the reaction was successful. Preparing Isopentyl Acetate by the Fischer Esterification Introduction: The purpose of this experiment is to synthesize isopentyl acetate via an esterification reaction between acetic acid and isopentyl alcohol, using concentrated sulfuric acid as a catalyst. The product will be washed, distilled, then characterized using infrared spectroscopy. Materials Used: Paraffin sand bath test tube clamp 50-mL Erlenmeyer flask Hickman still cork Pasteur pipettes with bent ends microspatula Kim-wipes sand bath vial Pasteur pipettes Rubber bulbs Reagents and Properties: Reaction and its Mechanism: Substances Formula Weight g/mol Quantity Moles Used Mole Ratio Melting Point °C Boiling Point °C Density g/mL Acetic Acid 60.05 2 mL 0.0349 1 to 1 118 N/A 1.049
Purpose: • To produce cis-endo-Bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride from cyclopentadiene and Malic Anhydride, using cycloaddition as the mechanism. • To find the purity using the melting point Procedure: Reference: Experiment 10.Cycloadditions: The Diels-Alder Reaction. Hart, H., Crane, L. E., Hart, D. J., and Vinod, T. K., Laboratory Manual for Organic Chemistry: A Short Course, 12th ed., Brooks/Cole, Cengage Learning: Belmont, 2007,pages 133-142. Modifications: - Maleic anhydride weighed in an Erlenmeyer flask - Warm on a hotplate - Wash product with a little ice cold ether - Dry product on large filter paper Observations: Table 1: measured values Compound/Item Measured value Maleic Anhydride 4.4917g Product 4.8398g Product melting point 123.5-141.6 oC Table 2: observed reactions Reaction Observation Warmed Maleic anhydride + ethyl acetate -Maleic anhydride (white powder) dissolved into a clear colourless liquid Adding Ligroin and cooling -Turns to a clear liquid with a white precipitate Adding Cyclopentadiene -Cloudy white liquid during mixing -settled to a bottom layer of white precipitate and a top clear colourless liquid Product White powder During melting point White powder slowly melted to clear colourless liquid Conclusion: In this experiment cis-endo-Bicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic anhydride was made, and there was a final mass of 4.8398g. Also, the product was light white fluffy crystals.
The Fajan method is named after American physical chemist Kazimierz Fajans and a dichloroflourescein indicator is used to indicate the equivalence point. The equivalence point in noted when the solution changes to a pink colour. The Mohr method is named after German chemist after Karl Friedrich Mohr and uses potassium chromate (K2CrO4). The colour of the solution at the equivalence point changes to a brownish red colour2. The following reaction has taken place to completion by the equivalence point: 2Ag+ (aq) + CrO42- (aq) → Ag2CrO4 (s)2 The second technique used in the experiment is the gravimetric technique.
Each test (for Iodine (I2), for Iodide (I-), and for Triiodide (I3-)) match the standard for each reactant (I2, I-, I3-). For example, when testing for I2 we mixed 1/3 of our home-made tincture and added the reagent mineral oil. Mineral oil, unlike water, is nonpolar and when mixed with nonpolar iodine, like dissolves like. Iodine mixes with mineral oil and a purple color is observed. Therefore our standard results matched our home-made results.
This is a neutralization reaction between a strong acid and strong base. Therefore the heat of reaction (∆H2) is called as the heat of neutralization of HCl and NaOH solutions. The ∆H2 calculated from this experiment is -6.6944KJ/mol. This is because the enthalpy changes when one mole of H+ ions from an acid (HCl) reacts with one mole of OH- from an alkali (NaOH) to form one mole of water molecules under the stated conditions of the experiment. In the final reaction of the experiment (Part C), solid NaOH will react with an aqueous solution of HCl.
Essential to the effectiveness of many of these anesthetics is the aromatic ring at one end and possibly a secondary or tertiary amine at the other end of the molecule, seperated by a one- to four-unit hydrocarbon chain. In this experiment, we will synthesize benzocaine, one of the simpler local anesthetics, from para-amino benzoic acid and ethanol in the presence of conc. sulfuric acid. Benzocaine is an odorless, white, rhombohedric crystal with low water solubility. It is sensitive to light exposure and to temperatures above 30° C. As a drug, it has a low potency and low systemic toxicity.