Formation of an Alkene by Alcohol Dehydration

Formation of an Alkene by intoxicantic beverage Dehydration Lab Report Balanced Chemical Equation for the primary(prenominal) Reaction Mechanism The savage-catalyzed dehydration of secondary and tertiary alcohols involves non-isolable carbocation intermediaries. In the inaugural step of the of the reaction mechanism below, a phosphorous venereal disease gun adds a proton to the oxygen atom of the alcohol to form an oxonium ion. The OH is converted to a better leaving mathematical group as the positive charge on the oxygen weakens the carbon-oxygen oblige. The carbon-oxygen bond breaks during heating giving water an unstable carbocation.Without a nucleophile, the carbocation intermediate loses a proton from a carbon and forms a carbon-carbon double bond from the carbon-hydrogen electrons. The formation of a carbocation intermediate from the loss of a leaving group classifies this as an Elimination Reaction. Table of Reagents Pertinent Safety Information The phosphoric acid in this lab is a corrosive acid. Caution must be used to not get the acid in feeling with skin or clothes. Gloves must be worn while effusive it. If there is a spill, wash the ara with large amounts of water.Cyclohexanol, and especially cyclohexene, are very flammable liquids. Do not use an open flame as a source of heat with these substances. Outline of the Procedure amount 20 mL of cyclohexanol and 5 mL of 85% phosphoric acid to a 50-mL round-bottom flask along with 1 or cardinal boiling chips Swirl the flask thinly to thoroughly mix the layers and check this into a unproblematic distillation column Heat the flask until distillation begins and slowly distills the mixture, controlling the heating so that the temperature of the distillation vapor does not go above 100-105 degrees C.Cool the receiver in an ice bath to reduce the loss of distillate to evaporation Continue the distillation until scarce 5-10 mL of high-boiling residue is left in the flask Allow the flask to cool and disconnect the apparatusTransfer the distillate to a separatory displace and shake it with 10 mL of saturated sodium chloride solution, then spill off lower aqueous layer work 5 mL of 10% sodium carbonate to solution to neutralize any acid, gently shake the mixture, and drain off the lower aqueous layer once more Pour the upper layer into a dry, clean Erlenmeyer flask Add 1-2 g of anhydrous calcium chloride, and allow the flask to stand for 15-20 proceeding with occasional stirring Clean and dry the condenser, distillation flask and adapters for the final exam distillation Decant or filter the dry cyclohexene from the calcium chloride into a dry distillation flask and set up a simple distillation apparatus Add 1-2 boiling chips to the flask and distill the cyclohexene, appeal the liquid that boils between 79 and 85 degrees C in a small graduated cylinder Data and Observations The purpose of this lab is to combine cyclohexene from cyclohexanol using phosphoric acid. Thi s student had difficulties maintaining the temperature of the distillation vapor between 100-105 degrees C. the distillate recovered that was between 79 and 85 degrees C was discarded. The receiver was located in an ice bath to reduce evaporation. A total of 21 mL was collected. Results and Discussion Volume of cyclohexene 2. 8 mL Weight from immersion of cyclohexene (0. 810 g/mL) / (2. 8 mL) = *0. 29 g cyclohexe*ne Percentage restoration of cyclohexene 20 mL x 0. 960 g/mL = 19. 2 g = 0. 192 mol 0. 192 mol x 82 g/mol = 15. g x 1mL/0. 81 g = 19. 4 mL (Theoretical Yield) 2. 8 mL/19. 4 mL x 100 = 14. 4% Yield (but of thin quality) In a small test tube, add 5 drops of cyclohexene to 1 mL of 0. 5% aqueous potassium permanganate solution The solution glowering brown immediately and then formed a dark, thick fall down within 1 minute 1 mL of a 2% solution of bromine in carbon tetrachloride The solution immediately morose clear, and remained that way throughout the lab Conclusions Th e dehydration of alcohols is one of several methods to elevate alkenes. This dehydration may be accomplished using a infrangible mineral acid such as sulfuric and phosphoric acid.The archetypical step in this transformation is protonation of the hydroxyl group by the acid yielding an excellent leaving group. Next water is eliminated from the molecule resulting in a carbocation intermediate, which then eliminates a proton to form an alkene. Questions Name and draw the social organisation of the alkenes that might be obtained by acid-catalyzed dehydration of 2-methylcyclohexanol 3-methyl-3-hexanol What would be the best alcohol to use in an acid-catalyzed dehydration to prepare 1, 3-dimethylcyclopentene? The most suitable alcohol to use is 2*, 5*-dimethylcyclopentanol. Write equations to show the products that form in the reactions of cyclohexene with potassium permanganate and bromine.