For this experiment, an addition mechanism for the bromination of an alkene was observed along with studying chirality. The bromination of the substituted alkenes was known as an oxidation reaction and it produced different stereoisomers based on the alkene’s geometry. The E-stilbene when exposed to bromine produced dibromostilbene. Three products can potentially form from this reaction which are meso, D, and L stilbene bromide. The goal of this experiment was to identify which stereoisomer predominated in the reaction and determine the most favored cation intermediate. The first step of the mechanism was to break the alkene pi bond and form a new C-Br bond. When the alkene broke, a secondary carbocation formed. The bromide anion attached to …show more content…
In a round bottom flask, both the E-stilbene and the DCM were added along with a rice stir bar. When stirring the solution containing the bromine, it is safer to place a keck clamp on the top of the round bottom flask and rest the stopper on top, so no solution flies out of the round bottom flask. This prevents sealing to occur and protects against bromine exposure. Sealing is dangerous because DCM is a high vapor pressure and if the system is sealed then this can lead to a pressurized system which is not safe. The stir bar was used to dissolve the solid. Then bromine was also added to the solution. Then the solution was stirred once more for ten to fifteen minutes or until the orange color had mostly disappeared and a white solid had formed in a colorless solution. After this, the precipitate product was isolated and filtered by using a Buchner funnel and was washed with cold DCM to ensure the removal of most of the bromine and any unreacted starting material as well as most of the D/L isomer. Once the product has dried, the weight of the product was recorded and the percent yield. The melting point was also taken to ensure that all of the unreacted starting material along with the D/L isomers had been removed from the
In a test tube, 0.5mL of the sample will be added with 0.5 mL of water and shaken vigorously. Take note for its solubility by parts (0.5mL is one part). Keep adding parts of the solvent until the sample is soluble. If not, add until ten parts of the solvent and determine its solubility. To separate test tubes, water will be replaced with ethanol, chloroform, ether, and acetone as solvents. Same procedures were
For the Bromination of Toluene lab the ratio of the ortho, meta and para ratio in the bromotoluene product mixture was determined using quantitative IR spectroscopy. For the toluene to be mixed with bromine it must undergo Electrophilic Aromatic Substitution and it needs to be in the presence of a Lewis acid catalyst. Additionally, a metal staple must be used to generate a ferric bromide catalyst. The three products of brominating toluene are ortho-bromotoluene, meta-bromotoluene, and para-bromotoluene. There are five reactive sites on the aromatic ring where the hydrogen atom is replaced by a bromine, the ratio for this is 2:2:1 ortho, meta and para.
The results of our TLC plate for point B is consistent with the nature of the sample, which is a mixture of the trans and cis isomers. Two spots were observed with considerable differences in their polarities. Point C produced two spots after our TLC plate procedure; that is an indication of impurity, since point C was supposed to be only composed by cis isomers. The second spot, was observed to have similar factors to point A, it is possible that the impurity is due to the isomerization of cis isomer to trans. The isomerization reaction for this compound undergoes by radical reaction.
Upon completion of the reaction, the greenish-blue precipitate was vacuum filtered and weighed. A mass of 0.4194g of VIVO(acac)2 with a percent yield of 24.8%. The percent yield was low, but that was most likely due to not allowing
In this experiment, the addition of Bromine to an alkene was done. In doing so the solution undergoes a halogen addition reaction, which is a simple reaction where a halogen molecule is added to a double bonded carbon0carbon alkene functional group. In this experiment cholesterol (the alkene used) is dissolved in 2 mL of methyl tert-butyl ether and Bromine (halogen) is added to the solution to create a reaction.
Addition reactions allow the reaction of two or more reactions to form into the adduct (the larger molecule formed). However, this only applies to compounds that have multiple bonds, for instance a double or triple bond. In this experiment, the reaction will be an addition of HBr to 1-hexene (an alkene). Both reactants are in reflux, which allows one to determine whether 1-bromohexane or 2-bromohexane is formed. In the reflux setup, 0.5 mL of 1-hexene, 2 mL of 48% HBr (aq), and 150 mg (0.15g) tetrabutylammonium bromide is added and then heated for two hours, along with stirring (using a spin vane).
By applying the general solubility rules listed below, the precipitate or lack of were then able to be analyzed to determine each substances identity after mixing on a spot plate. Given that specific compounds react differently when mixed with another substance, the precipitate, pH, and chemical equation of the reaction itself was utilized in determining the substance. Procedures such as the one conducted in this experiment are especially useful in determining which chemical is which, if it is unable to be deduced through pH, smell, or
Purpose: In this experiment, I performed a Diels-alder reaction by refluxing anthracene with maleic anhydride in xylenes to form a bridged bicyclic product at high temperature. The reflux technique involves continuous boiling of a solution to the temperature of reaction solvent where evaporating solvent is condensed back into the original reaction flask. The product was collected by recrystallization technique and characterized using melting point.
Green chemistry is a concept that allows chemist to do experiments that are more environmentally friendly. In the formation of bromotoluene the solvents were not regenerated, as seen in process mass intensity (PMI) calculated was 314.27 indicating high waste due to low theoretical yield. The reaction did not follow principle 2, which is the regeneration of solvent indicates maximization the materials. In this experiment the waste product produced was N- succinimide, which is not a super toxic product indicating clean up is not harsh to the environment stated in principle 4. A catalyst was used in this experiment, which follows principle 9 of green chemistry stating a catalyst removes the use of large quantities of reagents to generate the reaction.
The reaction is as follows: The product of the reaction when benzyl is reduced can create three stereoisomers. The first carbonyl on the benzyl may be attacked by the hydride, which is either from the back, or the front, which would give
The alkene gas released in this experiment is propene gas. Elimination reaction is the reaction that takes place as the reaction releases propene gas instead of producing propanol (alcohol). The type of elimination reaction that takes place is dehydrohalogenation, namely dehydrochlorination because the halogen in 2-chloro-2-methylpropane is chlorine. Propene released by the dehydrochlorination is unsaturated hydrocarbon that contains double covalent bond between carbon atoms, CC. Addition reaction, halogenation occurs when bromine water is added to propene to form 1, 2dibromopropane with chemical equation:
Resonance allowed for the arenium ion to be stabilized and for the carbocation to move throughout the ring until it reached the acetanilide substituent containing the acetamide group. Acetamide groups contain an NH atom
This product was then recrystallized to improve its purity. The recrystallization required a mixed solvent consisting of mostly ethanol and a small amount of water; no other suitable solvents are readily available to perform this recrystallization. One of the possible contaminants could be potassium bromide formed from the bromine and potassium ions left over in solution after the dehydrobromination reaction. If this contaminant was incorporated into the diphenylacetylene crude crystals and was not removed with the ice and water used to cool down the reaction media, it could be removed with the small amount of water in the recrystallization solvent since KBr is soluble in water and not very soluble in ethanol. The product was dissolved in at least 1 ml of heated ethanol (more was added if that was not enough to dissolve the
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.
After identifying the solvent to be used, the group placed 2.00g of unknown C into a 125mL Erlenmeyer flask with 40mL of water. A 50mL flask with 25mL of water was placed on the hot plate to be added to the Erlenmeyer flask later. The group placed the Erlenmeyer flask onto a hotplate and added a wooden stick and 5mL of boiling water to the flask to help stir. The 5mL of boiling water was added by pipet to ensure the compound was dissolved completely. Gravity filtration was then performed using a stemless funnel and a heated fluted filter paper, which was heated by the second 50mL flask. The gravity filtration took place in a 125mL Erlenmeyer flask, and then was allowed to cool to room temperature and then placed in an ice bath for recrystallization. After the crystals formed, vacuum filtration was used to separate the liquids and impurities using suction created by the force of running water. Once the filtration was complete the crystals were washed three times with pure cooled solvent(water). Once washed, the group then placed the newly formed crystals on a watch glass to