Mechanism 4 shows the debromination of 2α-bromocholestan-3-one to give 4. This mechanism which is similar to a Favoskii rearrangement, is likely to go via this path as other research has shown that there is often a by-product with this reaction. The by-product is cholest-4-en-3-one which requires the intermediate seen in the third molecule in the above mechanism. The intermediate is highly strained and with the presence of base a proton will be extracted which aids the collapse of the three membered ring. To gain the major product, 4, the H1 proton is removed, however it is very possible that the H4 proton is removed instead which would leave the minor product of cholest-4-en-3-one. Both products result in conjugation which will stabilise the molecule. The mechanism for this step is unlikely to go via a simple elimination as for an elimination the eliminated products must be trans to each other for facile leaving. As the bromine is equatorial in both the chair and the boat conformation the bromine is trans with neither of the hydrogens which shows this type of elimination is unlikely to occur. The other possibility is that the acidic hydrogen that is removed in the first step is not H4, but H2. This…
The goal of this experiment is to learn to make Grignard reagents. The reactions of the Grignard reagents with ketones form tertiary alcohols. These reagents are highly air- and moisture-sensitive materials. We will observe the formation of the Grignard reagents, which magnesium metal is transformed into organometallic salts.…
It was used to absorb excess CO2 and to make it precipitate at the bottom of the vial, so as to avoid any disruptions with the readings.…
Place magnesium ribbon in a clean crucible (on a clay triangle above a Bunsen burner). Heat until the magnesium begins to burn.…
The purpose of the bromination of arenes was to determine the different reactivities of different hydrocarbons with different hydrogen atoms when reacted with bromine under free-radical substitution. The time it took for the bromine color to disappear was used to determine the order of reactivity of the different hydrocarbons.…
(Please indicate if you performed the lab on a day other than your regularly scheduled day and/or with a TA other than your regular TA).…
The experiment was done twice in trial 1 and 2. First, in the first trial, the crucible with lid was measured on a balance and the mass of them was recorded in grams which is m of clean crucible = 22.89g . This was followed by weighing the crucible with 0.3 g of Magnesium on a balance. The total mass of mg with the crucible was recorded which was m total mass mg + Crucible = 23.19g. Then the magnesium was heated using a Bunsen burner, and we put the crucible with Mg on a clay triangle using tongs in order to get MgO compound.…
Burning magnesium Place magnesium ribbon in a clean crucible (on a clay triangle above a Bunsen burner). Heat until the magnesium begins to burn.…
The Grignard reagents are alkyl magnesium halides, R-Mg-X were first introduced in 1900. These reagents are usually prepared by reacting one atom with one molecule or by other means magnesium and alkyl halide in the presence of dry alcohol free ether.…
Objectives: 1. To examine a variety of reactions including precipitation, acid-base, gas forming, and oxidation-reduction reactions. 2. To identify the products formed in these reactions and summarize the chemical changes in terms of balanced chemical equations and net ionic equations. 3. To identify the species being oxidized and reduced in oxidation-reduction reactions and determine which species is the oxidizing agent and the reducing agent. Chemical equations represent what occurs in a chemical reaction. For example, the equation HCl (aq) + NaOH (aq) → NaCl (aq) + H2O (l) describes an acid-base reaction, a type of exchange reaction in which the driving force is the formation of water. In an exchange reaction, the…
Place magnesium ribbon in a clean crucible (on a clay triangle above a Bunsen burner). Heat until the magnesium begins to burn.…
The major findings contributing to the experiment is being able to determine and distinguish what moles have evolved thus being the hydrogen moles evolved allowing the magnesium to be consumed within the reaction.…
A. Observing and classifying types of changes of matter A.1 Ice Observations: ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ Type of Change: ________________________________________________________________ A.2 Milk and Vinegar Observations: ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ Type of Change: ________________________________________________________________ A.3 Magnesium and Oxygen i. Initial appearance of…
This experiment was performed to demonstrate a cycle of chemical reactions involving copper. This lab will start with copper as a reactant in the first reaction through a series of five chemical forms of aqueous phase reactions and ending to calculate the percentage of recovered solid copper as a product in the last reaction of the experiment. The experiment resulted in a percent recovery from the cycle of copper reactions of an increase to 139%.…
This aim of this experiment was to determine whether or not a chemical reaction occurred after the mixing of various chemicals. The evolution of a gas, the formation of precipitation, and the change of temperature or color are all indicative of a chemical reaction. It was assumed that a reaction did not take place if the mixture of chemicals exhibited none of these characteristics. Several precipitation, complex-ion formation, redox, and acid-base reactions were performed.…