In this lab, the goal is to explore the idea of elimination reactions and investigate ways to synthesizes alkynes. The product that will be produced is diphenylacetylene and this will be done by starting with meso-stilbene dibromide using elimination reactions. The balanced reaction is:
For an E2 reaction to occur, strong bases should be utilized for this lab since E2 reactions favor well with strong bases. KOH is a strong base that is also acts as a strong nucleophile. This is because it contains a hydroxyl group and they are both strong bases and nucleophiles.
Heat will also be applied to encourage the chemicals to go through the elimination reaction. There will be two ways to apply heat so that the reaction can occur. The first way is through a thermal reaction process using sand baths to heat the reaction. The other method of heating is to microwave the product so that the elimination reaction can
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A flea stir bar and 4.0 mL of 95% ethanol were added to the microwave reactor vessel. The solution was then stirred using a magnetic stirrer until all the KOH dissolved. 1.0 g of meso-stilbene dibromide was added in the microwave reactor vessel. The cap of the vessel was placed, tightened and the vessel was placed in a microwave reactor carousel. After the reaction was complete, the vessel with the mixed reaction was placed in a tap water bath so that it may be cooled. After it cooled down, 10 mL of DI water was placed in a 50 mL and the reaction mixture was poured into there to precipitate the product. The product was then collected by vacuum filtration and Hirsch funnel. The product was rinsed with 3 mL of DI water three times. The product dried on the filter paper with the vacuum on for 5 minutes after the rinse. The product was then placed in a drawer so that it may completely dry so that the weight and the melting point may be recorded later. The final product was a light brown
And finally into test tube 3, I pipetted 1.0 ml turnip extract and 4.0 ml of water. The contents of test tube 1 was poured into a spectrometer tube and labeled it “B” for blank. “B” tube was now inserted it into the spectrometer. An adjustment to the control knob was made to zero the absorbance reading on the spectrometer since one cannot continue the experiment if the spectrometer is not zeroed. A combination of two people and a stop watch was now needed to not only record the time of the reaction, but to mix the reagents in a precise and accurate manner. As my partner recorded the time, I quickly poured tube 3 into tube 2. I then poured tube 2 into the experiment spectrometer tube labeled “E” and inserted it into the spectrometer. A partner then recorded the absorbance reading for every 20 seconds for a total of 120 seconds. After the experiment, a brown color in the tube should be observed to indicate the reaction was carried out. Using sterile techniques, any excess liquid left was disposed
3. Turned off the laboratory burner and observed the properties of the product in the evaporating dish.
Theory: One of the methods of preparing alkyl halides is via the nucleophilic substitution reactions of alcohols. Alcohols are inexpensive materials and easy to maintain. However, they are a poor leaving group the OH group is a problem in nucleophilic substitution, this problem is fixed by converting the alcohol into H2O.
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
The synthesis of acetaminophen involves the attraction of the electrophilic carbonyl group of acetic anhydride to the nucleophilic NH2
The product obtained had a melting point of approximately 107 °C and a weight of .324 grams. Some of the product would not dissolve in water and so was removed through vacuum filtration, which left .141 g not dissolved in solution. It took 13.2 mL of sodium hydroxide to turn the solution of the product dissolved in water pink. A molecular weight of 138.63 g/mol was calculated from the data. These results indicate that the product was 2-methylbenzoic acid, the Grignard reagent was 2-methylphenylmagnesium bromide, and the unknown bromide solution was 2-methylbromobenzene. Calculations showed that the limiting reagent of the Grignard preparation was magnesium and that the experiment had a 23.13 % yield.
After 10 minutes the reaction liquid was separated from the solid using a vacuum filtration system and toluene. The product was stored and dried until week 2 of the experiment. The product was weighed to be 0.31 g. Percent yield was calculated to be 38.75%. IR spectra data was conducted for the two starting materials and of the product. Melting point determination was performed on the product and proton NMR spectrum was given. The IR spectrum revealed peaks at 1720 cm-1, which indicated the presence of a lactone group, and 1730 cm-1, representing a functional group of a carboxylic acid (C=O), and 3300cm-1, indicating the presence of an alcohol group (O-H). All three peaks correspond with the desired product. A second TLC using the same mobile and stationary phase as the first was performed and revealed Rf Values of 0.17 and 0.43for the product. The first value was unique to the product indicating that the Diels-Alder reaction was successful. The other Rf value of 0.43 matched that of maleic anhydride indicating some
Purpose: The purpose of this experiment is to observe a variety of chemical reactions and to identify patterns in the conversion of reactants into products.
Once inverted, built-up gas was released by turning the stopcock to its opened and closed positions. This was repeated for about four times in one minute intervals. Then the layers were allowed to settle until a separation between liquids could be observed. Due to the low density of the product, the top layer was to be extracted. The bottom layer was carefully and slowly extracted out of the separatory funnel.
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 reaction is carried out in saturated aqueous ammonium chloride solution. Thus no special drying of solvents, reagents, or glassware is required. The reaction mechanism for this experiment can be seen below (Fig. 2)
The purpose of this experiment is to examine the reactivities of various alkyl halides under both SN2 and SN1 reaction conditions. The alkyl halides will be examined based on the substrate types and solvent the reaction takes place in.
The reaction took place in a conical vial and .2mL of each of the reactant samples were added to it along with some 95% ethanol. Two drops of NaOH were added shortly after and stirred at room temperature for fifteen minutes. The vial was cooled in and ice bath and crystallized. Vacuum filtration was performed to filter the crude product. The crude product was recrystallized using methanol and filtered again. We made one change to the procedure and instead of using .7mL of ethanol we
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.
Equipment, Materials, and Method The equipment used were a jacketed batch reactor beaker, cooling water circulation system, computer, LabPro temperature probe and conductivity probe, mixing stand and magnetic stir bar. The materials used for this reaction were a 0.08M NaOH solution and a 0.1M ethyl acetate solution. A 20% excess Ethyl acetate was used to ensure NaOH was the limiting reactant.[1] NaOH was chosen for the limiting reactant because of its high conductivity relative to Ethyl acetate. The extent of the reaction was monitored by measuring the conductivity throughout the reaction. With NaOH being the limiting reactant, the change in conductivity is more visible, and the termination of the reaction can