Bromination Of E-Stilbene Lab Report

What is the stereochemistry for the bromination of trans-cinnamic acid, and how is it formed?

The mixture was transferred to an ice bath to crystallize the product, after which the product was collected by vacuum filtration on a Hirsch funnel, washing the flask with small aliquots of cold xylene and pouring the solution over the crystals, allowing the vacuum to thoroughly dry the product. Additional drying was achieved by transferring the product to filter paper and pressing the crystals to remove any excess moisture. The product was then weighed and a melting point determined. A comparative TLC was run in Hexanes:Ethyl Acetate solvent against maleic anhydride to verify the purity of the

Discussion: In the synthesis of 1-bromobutane alcohol is a poor leaving group; this problem is fixed by converting the OH group into H2O, which is a better leaving group. Depending on the structure of the alcohol it may undergo SN1 or SN2. Primary alky halides undergo SN2 reactions. 1- bromobutane is a primary alkyl halide, and may be synthesized by the acid-mediated reaction of a 1-butonaol with a bromide ion as a nucleophile. The proposed mechanism involves the initial formation of HBr in situ, the protonation of the alcohol by HBr, and the nucleophilic displacement by Br- to give the 1-bromobutane. In the reaction once the salts are dissolved and the mixture is gently heated with a reflux a noticeable reaction occurs with the development of two layers. When the distillation was clear the head temperature was around 115oC because the increased boiling point is caused by co-distillation of sulfuric acid and hydrobromic acid with water. When transferring allof the crude 1-bromobutane without the drying agent,

The synthesis of the alkyl halide n-Butyl Bromide from alcohol is the foundation for the experiment. During the isolation of the n-butyl bromide, the crude product is washed with sulfuric acid, water, and sodium bicarbonate to remove any remaining acid or n-butyl alcohol. The primary alkyl halide halide n-butyl bromide is prepared by allowing n-butyl alcohol to react with sodium bromide and sulfuric acid. The sodium bromide reacts with sulfuric acid to produce hydrobromic acid . Excess sulfuric acid acts to shift the equilibrium and speed up the reaction by producing a higher concentration of hydrobromic acid. The

The product was placed in a Craig tube and several drops of hot (100°C) solvent (50% water, 50% methanol, by volume) was added and heated until all of the crystals dissolved. The Craig tube was plugged and set in an Erlenmeyer flask to cool. Crystallization was induced once the mixture was at room temperature by scratching the inner wall of the tube. It was then placed into an ice bath for ten minutes until crystallization was complete. The tube was then

The product was then suspended in 2 ml of water with a stir rod in a 50 ml Erlenmeyer flask and heated to boiling. Water was added in one milliliter increments until all the product was dissolved (18 ml added total). The saturated solution was allowed to slowly cool, and gradual white crystal formation was observed. Recrystallized product was collected once more by suction filtration with the Hirsch funnel once crystallization ceased. Collected product dried on a watch glass for a week, weighed 0.14 g (1.2 mmol), and the melting point was 139°-141°

Introduction This experiment was undertaken in order to create stilbene dibromide. Bromine is added through electrophilic addition in attacking the double bond. This experiment was also executed to determine the stereochemistry of this addition reaction, whether it created meso products or d,l products. Data and Results Initially, 0.9 grams of stilbene were added to the solution.

Dimethyl Fumarate was not successfully created during the course of this particular experiment, likely because of a failure of the bromine to mix with the other components of the test tubes. It was observed that the bromine had formed a separate fraction at the top of the rest of the test tube contents, and because of this the necessary reaction could not occur in substantial amounts for a precipitate of dimethyl fumarate to form. The amount of bromine that was in contact with the dichloromethane and dimethyl maleate was simply too small for a significant reaction to occur. The data discussed below is sourced from Alexander Boley. Alex reported the melting point range to be 94-97°C, with an accepted range of 102-105°C. The lower boiling point is most likely due to the compound not being dried sufficiently before the melting point was tested. Alex also reported isolating 0.348 grams of dimethyl fumarate. Since he utilized 0.5 g of dimethyl maleate solution, and the accepted density of dimethyl maleate is 1.153 g/ml, the theoretical maximum amount of dimethyl fumarate that could have been obtained is 0.5765 g; dimethyl fumarate would be present in the same amounts as it's steroisomer because of their identical constitution, so dimethyl maleate's density is a valid input for calculating the final amount of product. The result indicates that his percent yield was 60.36%. The percent loss indicated could be attributed to

Alkanes are relatively unreactive. There are only a few types of reactions commonly performed. In this lab, halogenation was performed. In the methane molecule, the

The wet, crude product was placed into the 50 mL Erlenmeyer flask. Small amounts of CaCl2 were added to dry the solution. The flask was sealed and the mixture was swirled and left to settle. Once

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 purposes of this experiment were to model a bimolecular nucleophilic substitution reaction between potassium hydroxide (KOH) with 1-bromopropane and determine whether it follows a second-order rate law mechanism. A rate constant of 0.0684 M-1 min-1 was obtained for this reaction at 45.1°C, which was determined through equilibrating the reaction and performing titrations of 0.390 M KOH with 0.1000 M hydrochloric acid (HCl). The activation energy calculated from class data was 50.188 kJ/mol, which deviated largely from the literature range value of 72.80–83.76 kJ/mol. It was concluded that the reaction was consistent with the predicted SN2 mechanism, based on the regression of a trendline.

The boiling range of the 1-pentyl ethanoate distillate was approximately between 149-151°C. This was indicated by the formation of the distillate and when the mixture of the purified 1-pentyl ethanoate started to vigorously

Determining how a mechanism comes to be is crucial as a scientist and arriving to conclusions is a crucial component which lead to examining and determining which mechanism takes place when two or more substrates are made to react. At the end of the experiment a mechanism was determined based on the purified product’s melting point. This was accomplished by having the reaction take place but also through acquiring the melting point and comparing the number to the melting point which was already established by the scientific community. (Q1) When 0.252 g of trans-cinnamic acid was mixed in 2.5 mL glacial acetic acid and 0.434g pyridinium tribromide was added, the resulting product reflects an addition reaction. In general, reactions take place to achieve its lowest Gibb’s free energy because it’s at

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.