Title: Dehydration Of An Alcohol: Cyclohexene From Cyclohexanol Objective: To produce cyclohexene through the acid catalyzed elimination of water from cyclohexanol. To understand mechanism involved in the reaction. To learn the technique of distillation. Introduction: A secondary alcohol, such as cyclohexanol, undergoes dehydration by an E1 mechanism. The key intermediate in the mechanism is a cyclohexyl cation, which can undergo substitution as well as elimination. To prepare a cyclohexene (olefin) in good yield, it is necessary to suppress the substitution reaction. In this experiment, the substitution reaction is suppressed by: (1) the use of strong acids with anions that are relatively poor nucleophiles ; (2) a high reaction temperature, …show more content…
Specifically, the side products are dicyclohexyl ether, polymer, mono and dicyclohexyl sulphate, and degradation products such as carbon, sulphur dioxide and carbon dioxide. The dehydration of cyclohexanol is carried out in such a way that the product, cyclohexene, distils from the reaction mixture as it is formed, the distillation technique serves to remove the olefin from contact with the sulphuric acid before polymerization can set in and it also serves as a first stage in the eventual purification of the olefin. The products and side products fall three categories: (a) gases, composed of sulphur dioxide and carbon dioxide and carbon dioxide, (b) distillate, composed of cyclohexene, un-reacted cyclohexanol, water and traces of sulphurous acid; and (c) residue, composed of high-boiling or non-volatile substances such as dicyclohexyl ether, mono- and dicyclohexyl sulphate, polymer and …show more content…
Experimental Procedure: 10.0 g of cyclohexanol and 2 mL of conc.(85%) phosphoric acid were placed in a 50 mL ST round bottomed flask and the two were mixed by swirling. Several carborundum porcelain or anthracite boiling chips (do not use marble chips) were added, the flask was clamped to a ring stand at Bunsen burner height, and a take-off distillation adapter was attached, a thermometer, a condenser, and a small receiving flask. The reaction mixture was heated so that it boils gently and distillate boiling in the range 85-90 ℃ was obtained. When the distillate was exhausted, the heat was increasing gradually. The same receiver was using; the distillate boiling was collected in the range of 90-100℃. The two liquid layers were tested in the receiving flask to see which the aqueous layer was. With the aid of a 9-in disposable pipette, the aqueous layer was drawn off and discarded the aqueous layer. The organic layer remaining in the receiving flask was dried by adding to it 0.1-0.2g of anhydrous magnesium
When the liquid level is above the calibration line on the pipette, remove the bulb quickly and put your thumb or index finger over the pipette. Carefully “roll” finger to the side and allow the liquid to drop until the meniscus is level with the mark. Then hold the pipette over the flask to receive the liquid and remove the finger. Allow the liquid to drain out.
The first procedure requires one 10mL volumetric pipette, one 50mL buret, two small beakers, one labeled “vinegar” and the other labeled “NaOH”, three 250mL Erlenmeyer flasks, labeled one, two and three, and one large beaker for waste collection. Collect 50mL of vinegar in the beaker labeled “vinegar” and record the brand and listed concentration of vinegar. Then collect about 60mL of NaOH in the beaker labeled “NaOH” and record its concentration.
If the elimination happens with either protons in the terminal methyl group, the resultant product is 1-butene, a Hoffman product (monosubstituted alkene). In contrast, elimination of either -hydrogens by the conjugate base of sulfuric acid (HSO4) on the methylene group leads to an alkene that is dissubstituted. Either the cis- or trans-2-butene can form depending on which hydrogen is deprotonated. These are the Saytzeff products since they are the most popular ones. In this case, the trans-alkene is the most stable, thus one should see the greatest area for the second peak when analyzing the gaseous products under gas chromatography.
Variables --------- During the experiments, the water will be heated using different spirit burners containing different alcohols. I will be able to change different parts of the experiment. These are the. Volume of water heated:
Plan 1. Collect 4 different sized beakers 2. Boil some water in the kettle 3. Pour 50ml into each beaker 4. After 1 minute check temperature 5.
Then the reaction tube was capped but not tightly. The tube then was placed in a sand bath reflux to heat it until a brown color was formed. Then the tube was taken out of the sand bath and allowed to cool to room temperature. Then the tube was shaken until a formation of a white solid at the bottom of the tube. After formation of the white solid, diphenyl ether (2 mL) was added to the solution and heated until the white solid was completely dissolved in the solution. After heating, the tube was cooled to room temperature. Then toluene (2 mL) was added to the solution. The tube was then placed in an ice bath. Then the solution was filtered via vacuum filtration, and there was a formation of a white solid. Then the product was dried and weighed. The Final product was hexaphenylbenzene (0.094 g, 0.176 mmol,
Once the mixture had been completely dissolved, the solution was transferred to a separatory funnel. The solution was then extracted twice using 5.0 mL of 1 M
The product was made from 4-methylcyclohexanol. The chemical, 4-methylcyclohexanol is used in industrial settings. In 2014, West Virginia was exposed to this chemical in drinking water. Since this chemical is used to wash coal of its impurities, it was unsafe to drink the water as well as take a shower (CNN). Similarly, 4-methylcyclohexanol has a strong smell which may cause people to have symptoms like vomiting, skin irritation, and trouble breathing. Diesel is also replaced by 4-methylcyclohexanol (National Geographic).
The first step taken within the experiment was to obtain and label three 400 mL beakers with the numbers 1 through 3 using a wax pencil. Once labeled, each beaker needed to be filled with a corresponding solution. The beaker marked with a “1” was filled with 200 mL of distilled water and
A condenser and heat reflux was used to prevent reagents from escaping. Then the solid product was vacuum filtered. The product was recrystallized to purify it and the unknown
The experiment required that a 250 mL beaker be filled with 75-85 mL of distilled water. Then between 25-30 grams of borax was weighed out using the electric analytical balance and added into the beaker of distilled water. To ensure that all of the borax was transferred from the weigh boat, it was washed with distilled water a few times and also added into the beaker. The beaker was place on to the hot plate and the stir bar was put inside the beaker. The thermometer was then place into the beaker close to its side; making sure it was not touching the bottom. The stirrer was turned on low and the borax was allowed to dissolve and reach saturation. After about five minutes, the stirrer was turned off to allow the solid to settle at the bottom of the beaker. The temperature of the borax solution was then recorded. A glass rod was used to carefully pour 5-7 mL of the solution from the beaker into a dry, clean 10mL graduated cylinder. The volume of the aliquot was recorded then poured into a 125 mL Erlenmeyer flask. To make sure all of the solution was successfully ...
The crucible and lid are heated at the beginning of the experiment before being weighed so that any moisture in the crucible is burned away.
2. In the large beaker, put water and boil it completely. After that, remove the beaker from heat. 3. Sample tubes (A-D) should be labeled and capped tightly.