I. Objectives * Be able to prepare cyclohexene from the dehydration of cyclohexanol * Understand the mechanisms of the dehydration reaction (acid-catalyzed dehydration). * Know how to use the necessary equipment for this reaction, such as the fractioning column. * Obtain positive results in unsaturation tests for the presence of carbon-carbon double bond (cyclohexene).
II. Background
Cyclohexanol, the reagent of this experiment, is used in the production of nylon, paints, plastics, detergents, textiles and pesticides. The dehydration of cyclohexanol to cyclohexene can be accomplished by pyrolysis of the cyclic secondary alcohol with an acid catalyst at a moderate temperature or by distillation over
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X. Results * After distillation the product was divided into two test tubes: One adding Br2 and the other one KMnO4 * Both test resulted in a colorless liquid, meaning a positive result for carbon-carbon double bond presence (cyclohexene).
Test 1: Addition of Br2:
Test 2: Addition of KMnO4:
* Both tests resulted in a colorless liquid, giving positive results for carbon-carbon double bond presence (cyclohexene).
XI. Discussion/ Conclusion
An alcohol can be dehydrated to form an alkene in the presence of a strong acid. We used 85% phosphoric acid and the alcohol is cyclohexanol. The reaction is carried out in a fractional distillation apparatus. As the alcohol and acid are heated, alkene and water are produced and distilled into a collection vial. The distillation process was long and we needed to be careful to not get any other product that cyclohexene; that is, we had to observe temperature changes, so the temperature would not affect the product yield. The distillation was continued until the temperature rose well over the boiling point of cyclohexene. At this point we assumed that the product has distilled into the collection vial.
To test our product for the presence of cyclohexene in the product, we
1. The first experiment is Preparation of a Cobalt Amine Bromide Product ; Synthesis #3 was used to create the compound. Added 5 grams of cobalt carbonate to 20 mL of hrdrobromic acid in a beaker. Noticied a slight color change to dark purple. Solution frothed after it settled I mixed in 15mL water and
The objective of this lab was to create a ketone through an oxidation reaction using a using a secondary alcohol and oxidizing agent in order to use that ketone in a reduction reaction with a specific reducing agent to determine the affect of that reducing agent on the diastereoselectivity of the product. In the first part of this experiment, 4-tert-butylcyclohexanol was reacted with NaOCl, an oxidizing agent, and acetic acid to form 4-tert-butylcyclohexanone. In the second part of this experiment, 4-tert-butylcyclohexanone was reacted with a reducing agent, either NaBH4 in EtOH or Al(OiPr)3 in iPrOH, to form the product 4-tert-butylcyclohexanol. 1H NMR spectroscopy was used to determine the cis:trans ratio of the OH relative to the tert-butyl group in the product formed from the reduction reaction with each reducing agent. Thin-layer chromatography was used in both the oxidation and reduction steps to ensure that each reaction ran to completion.
A 0.5 g of sodium tungstate dihydrate was weighed and transferred into a 50-mL round-bottom flask with a magnetic stir bar. Approximately 0.6mL of Aliquat 336 was then transferred carefully into the round bottom flask using a 1mL syringe. The round bottom flask and its contents were then set up in an oil bath. 11mL of 30% hydrogen peroxide and 0.37 g of potassium bisulphate were added to the reaction mixture in the round bottom flask and stirred using a magnetic stirrer. Lastly, 2.5mL of cyclohexene was added using automatic dispenser and the mixture stirred. A condenser was fitted on the round bottom flask, clamped and attached to water horses. The reaction mixture was then heated on the oil bath and the reflux process initiated for an hour while stirring the mixture vigorously. Half way while rinsing, any trapped cyclohexene in the condenser was rinsed. After 1 hour, the round bottom flask was rinsed
In doing the lab, one was able to determine the characteristics of the given solutions, containing different macromolecules, whilst doing the multiple tests. The tests performed were,
14 mL of 9 M H2SO4 was added to the separatory funnel and the mixture was shaken. The layers were given a small amount of time to separate. The remaining n-butyl alcohol was extracted by the H2SO4 solution therefore, there was only one organic top layer. The lower aqueous layer was drained and discarded. 14 mL of H2O was added to the separatory funnel. A stopper was placed on the separatory funnel and it was shaken while being vented occasionally. The layers separated and the lower layer which contained the n-butyl bromide was drained into a smaller beaker. The aqueous layer was then discarded after ensuring that the correct layer had been saved by completing the "water drop test" (adding a drop of water to the drained liquid and if the water dissolves, it confirms that it is an aqueous layer). The alkyl halide was then returned to the separatory funnel. 14 mL of saturated aqeous sodium bicarbonate was added a little at a time while the separatory funnel was being swirled. A stopper was placed on the funnel and it was shaken for 1 minute while being vented frequently to relieve any pressure that was being produced. The lower alkyl halide layer was drained into a dry Erlenmeyer flask and 1.0 g of anhydrous calcium chloride was added to dry the solution. A stopper was placed on the Erlenmeyer flask and the contents were swirled until the liquid was clear. For the distillation
Me and my lab partner, obtained a mixture of a un known proportion from the instructor and then flow the guide line in our lab manual to separate the mixture by applying the separation method motioned in our lab manual pages 33-40 . In this experiment, the separation methods were decantation,
Alcohol dehydrations are widely used in many industries to produce alkene. In this experiment 2-methylcyclohexanol was dehydrated to three possible products using phosphoric acid as a catalyst. The main tool for this experiment is the Hickman still. First, Drierite was added to the Hickman still so that any excess water formed during the experiment will be absorbed. It also acted as a boiling stone and addition surface to increase surface area. Next, 0.75 mL of 2-methylcyclohexanol is added to the still and right after 1 mL of phosphoric acid is added. The phosphoric acid (H3PO4) acts as a catalyst in order for the reaction to occur. The mixture is heated up to between 120o Celsius and 160o Celsius. If the temperature goes above 165oC then
Whereas for simple distillation, the compounds need to be around 80C apart in order for proper separation to occur. Thus, cyclohexane and toluene were not able to be properly separated since the boiling point for cyclohexane was 80.74C while the boiling point of toluene was 110.6C—there two boiling points are fairly close to one another. Thus, the mole fraction for cyclohexane and toluene were fairly low when compared to cyclohexane and
Part 1: Obtain some 0.200M Fe(NO3)3 solution and some 0.00020M KSCN solution. Starting from the first solution, pour and mix 8.0mL of Fe(NO3)3 solution and 2.0mL of KSCN solution into a test tube, where as the second solution has 7.0mL of Fe(NO3)3 solution and 3.0mL of KSCN solution. Continue this process until 5 test tubes have been filled. Pour
7. Plan: Each student in a group of three will work to purify the product of the reaction with cis-stilbene, trans-stilbene, or styrene. The crude products will be purified through recrystallization. This purification process will be performed several times. When the recrystallization is complete, a vacuum filtration will be executed to filter out the crystals. An NMR spectrum will be taken of the recrystallized product.
The purpose of this lab was to carry out a dehydration reaction of 2-methylcyclohexanol by heating it in the presence of phosphoric acid and determining which alkene product would be the major product. Methylcyclohexanols were dehydrated in an 85% phosphoric acid mixture to yield the minor and major alkene product by elimination reaction, specifically E1. The alkenes were distilled to separate the major and minor products and gas chromatography was used to analyze the results and accuracy of the experiment. The hypothesis was the major product of the reaction would be the most substituted product. This conclusion was made because of
To tube 3 a piece of litmus paper was placed into the tube. Then as is tube 2 concentrated HCl was added drop wise until the litmus paper indicated that it is acidic. No CO2 gas will evolve.
The boiling range of the 1-pentyl ethanoate distillate was approximately between 149-151°C. This was indicated by the formation of the distillate and when the mixture of the purified 1-pentyl ethanoate started to vigorously
The purpose of this lab is to understand the process of eliminating an alkyl halide to form an alkene. The experiment is carried out by first converting the alcohol, 2-methy-2-butanol, into the alkyl halide of 2-chloro-2-methylbutane that will then be put through dehydrohalogenation that favors elimination reaction (E2) to create a mixture of 2-methyl-2-butene and 2-methyl-1-butene. A fractional distillation will be taken to purify the mixture and an additional gas chromatography will be done to further analyze the mixture composition. A bromide test will be done to determine the product of an alkene in the experiment.
The investigation stage of this report will focus on comparing fermentation and hydration as methods on producing ethanol. The report will detail each method on their physical production, hazards, environmental impacts and global production. From this the author will gain a clear understanding on each key area and then form a solid and justified opinion on which is the most effective method of producing ethanol.