Thursday, February 21, 2019

Preparation and Reactivity of Sn1 2-Bromobutane

Preparation and SN1 responsiveness of 2-Bromobutane capital of Minnesota DeJong De deviatement of Chemistry, Illinois State University, Normal, IL 61790-4160 Submitted April 4, 2013 Introduction The purpose of part 1 of the research lab is to prep atomic number 18 2-Bromobutane using SN1 reactions. The purpose of part 2 of the lab is to determine the relative reactivity of alkyl halides under SN1 conditions. Results and Discussion The general Reaction The Proposed Mechanism Experimental Procedure To prepare 2-bromobutane in part one of the lab, you have to set up a flaskful frame-up with a thermowell and a Claisen adapter.Attached to the Claisen adapter is a thermometer measuring the temperature in the flask and a vertical condenser for reflux. Add in the reactants to the flask, sulfuric acid, 2-butanol, and ammonium bromide. Heat to 95OC and then maintain temperature for 30 minutes. Then, water was added and simple distillate began. The aqueous layer of the distillate was removed leaving the product, 2-bromobutane. For part 2, cardinal drops of each of the following were placed in 3 different seek tubes 2-bromobutane, 1-bromoutane and 2-bromo-2-methylpropane.In each of the tubes an even amount of silver nitrate is added. Observations of the reactions precipitate are recorded. Same process is done with 2-chlorobutane, 2-iodobutane, and 2-bromobutane. Experimental Stoichiometry Compound Molecularweight Quantity Moles 2-butanol 74. 12 g 7. 4 mL (6. 0 g) 0. 081 Sulfuric acid 98. 08 g 20 mL (12M) 0. 24 Ammonium bromide 97. 94 g 8. 0 g 0. 082 The limiting reactant is 2-butanol. Yield Data 2-bromobutane Molecular metric weight unit 137. 02 gTheoretical Yield (moles) 0. 081 mol Theoretical Yield (grams) 11. 10 g Actual Yield 10. 11 g NMR remand Signal Chemical Shift Multiplicity Integration A 4. 11 Multiplet 1H B 1. 85 Pentet 2H C 1. 60 Doublet 3H D 1. 08 Triplet 3H Reactivity of Alkyl Halides Compound Observations at Room Temp Observations upon Heating 1-bromo butane sink Very little change but whatever white ppt 2-bromobutane actualize Moderately cloudy white ppt 2-bromo-2-methylpropane Brown tint Very whitish white pptCompound Observations at Room temp Observations upon heating 2-chlorobutane lightsome No ppt at all 2-bromobutane Clear Moderately white and some yellow ppt 2-iodobutane Dark brown Thick, milky white and yellow ppt closing Overall, the first part of the lab produced 2-bromobutane using SN1 reactions. This product was then employ in the second part of the experiment to determine the relative reactivities of alkyl halides. Reactivity increases as follows 1O 2O 3O and Cl- Br- I

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