Dehydration is the process of removing water, and it is a commonly used process to produce carbon-carbon double bonds Brown et al, The distillate will be a mixture of water and cyclohexene. Gently heat the mixture to no more than oC degrees and continue heating. See Appendix 2. Aim: The objective of this exercise is to prepare cyclohexene from cyclohexanol and determine the efficiency of this conversion.
The mechanism of the Hickman Still is due to the different boiling points of the substances. Waste Disposal Dissolve or mix the material with a combustible solvent and burn in a chemical incinera- tor equipped with an afterburner and scrubber. When white fumes appear in the round bottom flask, and about 10 mL of distillate have been collected, discontinue the distillation. Targetorgans are the eyes, skin, and respiratorysystem. Procedure: Pour cyclohexanol
This is one of the most common methods of preparing alkenes. This causes the water to be removed, resulting in the unstable carbonium ion intermediate. Potential Exposure Cyclohexanol is used in making plac- ticizers, dry cleaning, dyebath; and textile finishing formu- lations; as a solvent for ethyl cellulose and other resins; it is used in soap manufacture; it is used as a raw material for adipic acid manufacture; as a nylon intermediate. Shipping UN Alcohols, toxic, flammable, n. Experimental 3 To begin this experiment, a Hickman Still was set up figure 3. You must wear eye protection at all times.
This carbocation can react in any of the ways shown below: 1. Figure 1: Dehydration of Alcohol Kho et al, In this experiment, cyclohexanol was dehydrated in the presence of phosphoric acid, which is a strong acid. Filtration by gravity will occur much more readily if you place a paper wedge between your funnel and your test tube. Use a collection flask or beaker that is no less than 50 mL in volume.
Transfer the cyclohexene into a clean dry conical flask and add a spatula full of calcium chloride. Allow the solution to stand over the drying agent for about fifteen minutes, then, by gravity filtration using cotton wool, filter the cyclohexene into a dried pre-weighed test-tube.
The completed distillate mixture was then transferred into a centrifuge tube, and then set standing upright for the mixture to separate. If the mixture is cloudy you will need to add another spatula full of calcium carbonate. Filtration by gravity will occur much more readily if you place a paper wedge between your funnel and your test tube. This exercise is termed "washing the cyclohexene with water".
Into a second test tube transfer approximately 2ml of cyclohexanol. Figure 2. To this mixture add NaCl until saturation no more will dissolve. Dicyclohexyl ether then is a probable side product of the dehydration of cyclohexanol.
Stopper your conical flask, swirl the mixture and allow to stand.
Immediately stopper the tube with a cork and discard the drying agent and cotton wool into the waste containers which are in the fume hood. The cyclohexanol used was provided by Fisher Scientific, the magnesium sulfate was provided by J. Now wash the cyclohexene where is it? This causes the water to be removed, resulting in the unstable carbonium ion intermediate. This carbocation can react in any of the ways shown below: 1. Note the color of each solution after addition of the bromine solution.
Run off the lower layer into a conical flask and set this aside. This causes the water to be removed, resulting in the unstable carbonium ion intermediate. Cover all containers of this compound and do not leave drying agent, glass wool or towels coated with the compound lying on the bench. The carbonium ion intermediate then quickly loses a proton to water to form the alkene Kho et al, To remove dicylcohexy ether completely a second distillation of the product is usually carried out.
A positive result for the formation of cyclohexene is indicated by a clear colorless solution upon addition of bromine to your product.
The completed distillate mixture was then transferred into a centrifuge tube, and then set standing upright for the mixture to separate. Redistil it from Na. Transfer the contents of the organic phase to a dry round bottom flask. Washing with water removes most of the impurities. Shelley Phu Synthesizing Cyclohexene from Cyclohexanol by Dehydration Abstract Cyclohexene was synthesized from cyclohexanol by dehydration in the presence of a strong acid, in this case, phosphoric acid. Falcone, Joe.