a) Write the equation for the esterification of 3-pentanol with acetic acid and

Question

a) Write the equation for the esterification of 3-pentanol with acetic acid and give a catalyst for the reaction. b) Given the equilibrium constant, K=2.0, calculate how many moles of esters you would obtain, at equilibrium, from 1 mole of 3-pentanol and 1 mole of acetic acid, and express the result in terms of & yield. c) What improvement in % yield would result by tripling the amount of acetic acid in this experiment? Please help me. I am very confused and am not sure how to go about this. Thank you SO much!!

Explanation / Answer

ORGANIC SYNTHESIS: MICROWAVE-ASSISTED FISCHER ESTERIFICATION Materials Needed ? 1.0-2.0 mL of an alcohol to be chosen from the following: 3-methyl-1-butanol (isoamyl alcohol, isopentyl alcohol), 1-octanol (n-octyl alcohol), phenylmethanol (benzyl alcohol) ? 2.0 mL acetic acid ? 10 drops concentrated sulfuric acid ? 0.2 g silica beads ? saturated aqueous sodium chloride (sat NaCl(aq)) ? 10% aqueous sodium bicarbonate (NaHCO3(aq)) ? anhydrous sodium sulfate pellets (Na2SO4(s)) ? 10 mL diethyl ether ? 1 GlassChem™ pressure vessel and torque tool for tightening cap ? 1 very large test tube, several small test tubes, 1 screw-cap vial, Pasteur Pipettes Textbook Reading Assignment Smith, Chapter 13.6 INTRODUCTION A carboxylic acid and an alcohol react in the presence of an acid catalyst to form an ester and water as shown in equation 1. This reaction, termed Fischer esterification in honor of its discoverer, can be used to prepare a variety of esters. The esterification reaction is reversible with an equilibrium constant that favors the products only slightly. Therefore, in order to get a decent yield of the ester product, an excess of one of the reactants is usually used to drive the equilibrium to the right (Le Chatelier's Principle). In addition, a drying agent, such as silica beads can be used to absorb the water side product as it is formed and again drive the equilibrium toward the products. However, this reaction is rather slow (even at elevated temperatures with the acid catalyst added); too slow to allow us to carry it out in a 2-hour lab period using standard heating methods. Luckily, WSU recently purchased a Microwave Assisted Reaction System (MARS) which will allow us to use microwave heating to speed the process. In this experiment you will choose one of the following three esters -- isopentyl acetate, benzyl acetate, n-octyl acetate -- and synthesize it by reacting acetic acid with the appropriate alcohol (3-methyl-1-butanol, benzyl alcohol, or 1-octanol) under microwave irradiation at 130 °C for 15 minutes. Concentrated H2SO4 will be used as a catalyst and silica beads added to absorb the water side product and drive the equilibrium. Once the reaction period is over you will need to carry out a several-step procedure designed to isolate the ester product as a pure substance (free from any leftover starting materials). This is a typical, though relatively simple, organic synthesis procedure. The weight of the product obtained (i.e. the yield) will be measured and the percent yield determined. The synthesized esters will also be assessed for their fragrance.

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