Bromination of (E)-Stilbene Kaisha Butz Lab Partner: Jenna Knafo Instructor: Dr. Beatrix Aukszi LA: Paige Swalley 10/28/2014 Abstract: The purpose of this experiment was to synthesize the second intermediate (meso-stilbene dibromide) in the E-Stilbene reaction by Bromination. It was hypothesized that if the reaction was heated at 120°C for five minutes the reaction between E-stilbene and the pyridium bromide perbromide would occur, and meso-stilbene would be created. After the reaction occurred the results were analyzed by IR and by an ignition test. The hypothesis was supported by the employed methods. Introduction: This experiment was performed to show how bromination of alkenes reacts, and to be able to successfully synthesize meso-stilbene dibromide. The reaction of bromine with alkenes is an addition reaction where the nucleophilic double bond attacks the electrophilic bromine …show more content…
This should be the case. The only difference in the spectroscopy was the lack of the carbon-carbon double bond in the meso-stilbene dibromide. The IR spectroscopy in the lab does not have the ability to measure the wavelength of carbon-bromine bonds because it is not within the range of the machine. Therefore, the two IR spectroscopies of the two substances were very similar because they both contained aromatic rings with similar wave numbers (cm-1) (Table 1, Table
Cadet Eric Wiggins Date: 18 September 2014 Course Name: Chem 100 Instructor: Captain Zuniga Section: M3A Identification of a Copper Mineral Intro Minerals are elements or compounds that are created in the Earth by geological processes. The method of isolating metals in a compound mineral is normally conducted through two processes.
Test such as Bromination, IR spectroscopy, refractive index, and measures physical properties confirmed that the product collected was the desired product, cyclohexene. A bromination
The goal of the experiment is to synthesize a bromohexane compound from 1-hexene and HBr(aq) under reflux conditions and use the silver nitrate and sodium iodide tests to determine if the product is a primary or secondary hydrocarbon. The heterogeneous reaction mixture contains 1-hexene, 48% HBr(aq), and tetrabutylammonium bromide and was heated to under reflux conditions. Heating under reflux means that the reaction mixture is heated at its boiling point so that the reaction can proceed at a faster rate. The attached reflux condenser allows volatile substances to return to the reaction flask so that no material is lost. Since alkenes are immiscible with concentrated HBr, tetrabutylammonium bromide is used as a phase-transfer catalyst.
The abundant of esters, which serves as the electron withdrawal group, propels the effectiveness of this reaction. In the present case, the central ring of the anthracene possesses the characteristic properties of a diene, electron-rich, system [1]. Thus, this aromatic compound reacts with the 9 and 10 positions of the maleic anhydride dienophile, electron-poor, by 4 +2 cycloaddition [1]. 9 and 10 are the position of preference because it is where new bonds can be made without destroying the aromatic formation of the other two rings. This reaction results in a six-membered ring bridged on the 9 and 10 positions of anthracene.
Introduction SN2 stands for substitution, nucleophilic, bimolecular and occurs in one step where the nucleophile and electrophile react: the nucleophile attacks the electrophile 180° from the leaving group.3 The leaving group is nothing more than a group that leaves the electrophile attacked by the nucleophile. In this experiment the nucleophile is bromide, the electrophile is 1-butanol, and the leaving group is hydroxide. However, bromide must first be obtained from hydrobromic acid which gets bromide from a reaction between sodium bromide and sulfuric acid. The hydrogen and bromide in hydrobromic acid reacts with the oxygen in 1-butanol and the carbon attached to oxygen respectively to form 1-bromobutane. The overall reaction of this procedure
Once the bromine was added to each test tube, the color of each test tube was monitored, and the time that a color change occurred in each test tube was noted. Bromine is red; when the solution was no longer red, it could be understood that the reaction had taken place. For the test tubes exposed to UV
Nevertheless, the latter is not used in this experiment since it is very reactive and extremely flammable. On the contrary, NaBH4 is relatively mild and it can be used with protic solvents. In this manner, 1.507 grs of the ketone 9-fluorenone were mixed with 30.0 ml of 95% ethanol in a 125 ml Erlenmeyer flask. The bright yellow mixture was stirred during 7 minutes until all the components were dissolved.
For each compound, a formal oxidation number for bromine is given, but the usefulness of this number is limited for p-block elements in particular. Based upon that oxidation number, an electronic configuration is also given but note that for more exotic compounds you should view this as a guide only.” found on (webelements.com). Bromines density is 3.11 grams per cubic centimeters (Phase at room temperature: liquid. Element Classification: non metal.
The relative reactivity was found by setting the reactivity per hydrogen of 1,4-dichlorobutane to 1.0. As shown in Figure 4, 1,3 dichlorobutane had the highest yield of 48% and the highest relative reactivity of 3. This is because it replaced the C-H bond that was furthest from the chloro substituent and formed a stable secondary intermediate. Next, 1,4-dichlorobutane had the second highest yield of 24%, but the third lowest reactivity of 1.0. Even though it was the furthest C-H bond from the chloro substituent, it formed a less stable primary radical intermediate.
Experiment 12: Dehydrobromination Discussion In this experiment, a double elimination reaction was performed on meso-stilbene dibromide, to form diphenylacetylene by eliminating two hydrogen and two bromine atoms in he presence of potassium hydroxide. The product was filtered and identified by comparing melting point data, and percent yield was calculated. Since an E2 reaction was performed in this experiment, the ideal conformation for the hydrogen and bromine would have been anticoplanar. However, since the phenyl groups were bulky and the atom was not symmetric, the hydrogen and bromine could at best be antiperiplanar.
Experiment 2 Report Scaffold (Substitution Reactions, Purification, and Identification) Purpose/Introduction 1. A Sn2 reaction was conducted; this involved benzyl bromide, sodium hydroxide, an unknown compound and ethanol through reflux technique, mel-temp recordings, recrystallization, and analysis of TLC plates. 2. There was one unknown compound in the reaction that was later discovered after a series of techniques described above.
Scheme: Reagents and conditions- a) K2CO3/MDC, 6h; b) TEA/MDC, 4h; c) TFA, 2h; d) 7a-j substituted benzyl bromides, K2CO3/MDC, 8h General procedure for the preparation of
This was proved by utilizing the IR spectrum to verify the C =O was not in the final product as it lacked the 1640 cm-1 peak. The melting point of 113-115 degrees C proved that the final product obtained was the E-Stilbene. The TLC plate proved that the E and the Z product was produced, show cased by the double intensity of the DCM spot to the final product’s spot, both which had an Rf of 0.92. The double intensity proved that both products were produced, but through heating and filtering, the Z-Stilbene was
After the nucleophilic substitution, the nucleophile can be neutral or carry a negative charge while the substrate can be neutral or positively charged. In this lab, a primary alcohol is converted to an alkyl bromide and a benzyl chloride into an ester using the SN2 reaction. Factors affecting the rates of both SN1 and SN2 reactions will also be investigated. In 1935, two scientists by the names of Sir Christopher Ignod and Edward D. Hughes, studied nucleophilic reactions of alkyl halides.
Here IB and BG are internal Bremsstrahlung and background respectively. The Perspex was then placed below the target compound and the spectrum IB+BG was recorded for the same time. The difference in the two spectra gives Raw EB spectrum. Data were accumulated each time for 12 hours. From several sets of data recorded, the average of the six sets of data in the energy region 200keV to 2000keV was used for the final analysis.