Title: Bromination of (E) – Stilbene (Microscale Procedure) Author’s Name: Reinaldo George Professor: Elvis Barrett Date of Experiment: Thursday July 16th 2015 Institution: Nova Southeastern University Abstract The purpose of this experiment was to synthesize the second intermediate in the b series of Sequential Reactions by carrying out the bromination of (E)-stilbene to obtain meso-stilbene dibromide. This product is the precursor to diphenylacetylene, the next synthetic intermediate in the b series. A further purpose of this experiment is to demonstrate the stereospecific addition of bromine to alkenes. The percentage recovery was also calculated and recorded. On completion of this experiment; my lab partners and I were able to successfully synthesize the second intermediate in the b series of the
Experiment 5: Preparation of Cyclohexene- Acid Catalyzed Elimination of Cyclohexanol Ball State University Organic Chemistry Lab 231 (Sec. 5) Dr. Bock/Daniel Miller Tiffany Raber 5 November 2012 Purpose: To prepare an alkene by an elimination reaction of an alcohol in the presence of sulfuric acid as a catalyst to produce a successful yield and desired results for the purity of the alkene. Introduction: The dehydration of an alcohol such as cyclohexanol is a useful technique for generating alkenes. The success of this reaction relies on a dehydration, such as the presence of a strong acid (sulfuric acid). Because this reaction is reversible, a fractional distillation is necessary to produce cyclohexene, water, and some impurities and a simple distillation is followed to further purify the product.
This product, dibromocholesterol, was washed and debrominated by an elimination reaction using zinc dust. Percent yield and recovery evaluated the efficiency of this synthesis. Melting point and thin layer chromatography (TLC) analysis assessed the purity of commercial cholesterol, dibromocholesterol, and synthesized cholesterol by physical analysis. Chemical tests evaluated the purity of these samples by assessing the presence of specific functional groups. Silver nitrate tested for 2o and 3o alkyl halides expected in dibromocholesterol and sulfuric acid tested for alkenes expected in cholesterol.
The reddish color of bromine is discharged upon addition to an alkene as the bromine reacts, making this reaction a useful qualitative test for unsaturation when the reaction has gone to completion. The mixture will still be stirred for thirty minutes, regardless of the change in color; since there is a production of an intermediate, the reaction goes by an SN2 mechanism and is dictated by second order kinetics. The dissipation of color will only indicate that the bromine in solution has reacted and not necessarily that the rest of the solution has gone to completion. While this solution is being stirred, the molecules of the mixture are coming in contact and the bromination reaction is occurring. The electrons of the polarizable pi bond in the alkene E-stilbene acts as a nucleophile, a chemical species that donates an electron pair, and attacks one of the bromines in the dibromide molecule, which then causes the sigma bond to break as well.
ABSTRACT Isopropyltoluene isomers were synthesized through the friedel-crafts alkylation of toluene with 2-chloropropane in the presence of aluminum chloride as a catalyst. Through extraction of the distillate with water and 5% NaHCO3, followed by a fractional vacuum distillation, the desired aromatic organic compound was isolated. Infrared Spectroscopy and Gas Chromatography were used to analyze the composition, purity and to confirm the identity of the prepared product. The sample weighed approximately 2.66g, which reflected a low yield at 47%. However, from the GC the area % (also known as percent purity) was 91.8%, which indicates that a very pure product was obtained.
Radu Purtuc | Chemistry 231 - Lab | Section 32 Ronnie :: team-member TECH 705, SEPARATING ACIDS AND NEUTRAL COMPOUNDS BY SOLVENT EXTRACTION - MACROSCALE EXTRACTION July 6, 2006 Lab Report INTRODUCTION Purpose: using extraction technique to separate acetanilide, p-toluic acid, and p-tert-butylphenol; then measure the melting points of each compound and comparing them to the statistical values. Background: separating acids and neutral compounds by solvent extraction is a useful technique used in practice by chemists to separate organic compounds from mixture of other compounds. It generally involve several steps, with limiting factors being the number and output purity of compounds to be extracted from source mixture. A number of specific compound solvents not inter-miscible are used to separate and dissolve compounds, and a physical transfer between solvents is employed. An example of use is cleaning compounds of impurities, where different solvents work as a molecular filter that interacts differentially with compound and impurities respectively.
Ashley Peccatiello Experiment 7 – Dehydration of 2-Methylclyclohexanol, Tests for Unsaturation, and Gas Chromatography Date Performed: October 25, 2012 Date Written: October 29, 2012 Purpose: To dehydrate 2-methylclyclohexanol to obtain two isomers. To separate the products by simple distillation. To analyze the sample by introducing the technique of gas chromatography and unsaturation tests. Reaction: Figure 1. Overall reaction of the acid-catalyzed dehydration of 2-methylcyclohexanol Figure 2.
| | | An Activity Series 1/9/13 Makieya DunhamPartners: Jasmine Lewis and Danielle Anderson | | | Problem Statement: In this lab we determined the activity series for five metals and for three halogens. In the first part of the lab we used a microscale technique to rank the metals that reacted with the other metal nitrates from most reactive to least reactive. The metal that reacts with another metal nitrate, then the solid metal have reduced the other metal ion and is the more reactive metal of the two. In the second part of the lab we used the solvent extraction technique to derive an activity series for the halogens. Safety Precautions: When in the lab we wore goggles, an apron, and gloves the entire time.
Introduction High performance liquid chromatography (HPLC) is used to separate compounds in a sample, identify compounds and can even be used to deduce the relative amounts of different compounds in a mixture. HPLC works under the same principle as thin layer chromatography using both a stationary and mobile phase. The mobile phase carries the mixture across the stationary phase which is used to separate the compounds. Although in HPLC mobile phase is tailor made to suit the polarity of the analytes. The mobile phase used in this particular experiment was Methanol and 0.1M sodium dihydrogen phosphate at a ratio of 30:70 and a pH of 4.5, slightly acidic.
Synthesis of 1-Bromobutane I. Conclusion In this experiment we prepare 1-bromobutane from 1-butanol by using Sn2 reaction. By heating the primary alcohol with two reagents: NaBr and H2SO4, an aqueous solution containing the alko-halide and water will be produced. The overall equation for the reaction: H2SO4 + NaBr + CH3CH2CH2CH2OH -------> CH3CH2CH2CH2Br + H2O + NaHSO4 Questions: 3- By changing the source of the halide from NaBr to NaCl: H2SO4 + NaCl + CH3CH2CH2CH2OH -------> CH3CH2CH2CH2Cl + H2O + NaHSO4 2- In refluxing you gently heating the mixture without losing product to evaporation. If the mixture were boiled some of the solvent that contains some products will be gone with evaporation.