Although some of the results obtained were not totally satisfactory, the general trend expected was persistent. Fluorenone as the limiting reagent was rapidly consumed by the Sodium Borohydride (NaHB4), this is confirmed by noticing the rapidly diminishing activity of Fluorenone, to the point that on the 3rd TLC plate Fluorenone is already absent (consumed by the reaction). One rationale Fluorenone was so rapidly consumed during the reaction, it is because, a hydrogen from the borohydride first attacks the carbonyl group on the Fluorenone molecule, leaving the oxygen with a nucleophilic site. Such a nucleophilic site can then speed up the reaction to the point that after 90 seconds all Fluorenone was consumed; methanol (CH3OH) is attracted
to the new nucleophilic site on the Fluorenone, causing Methoxide to be the leaving group (CH3O-). Correspondingly, it is important to mention, that after 90 seconds of reaction activity, the solution mixture which began with a yellowish appearance due to the Fluorenone, turned clear blue; and after 120 seconds of reaction, the solution appearance changed again from clear blue to crystal clear. This evidently indicates that Fluorenone was no longer being part of the reaction. Additionally, as observed during the course of the experiment and demonstrated by the calculated Rf values, Fluorenone to fluorenol reaction synthesis was brought to completion. In fact, the mean of the Rf values also indicate so. The Rf values of the product (0.29) were significantly lower than the Rf values of the reactant (0.51) throughout the reaction. This indicates a good molecular synthesis with little to low levels of contamination. Oppositely, the 313% percent yield calculated for Fluorenol obtained during the purification process is way beyond from expected results. Since the crystals collected contained and retained high amounts of water, a main reason for having such an elevated percentage yield could due to poor drying techniques. For the experiment, vacuum filtration on a Hirsch funnel was the technique used to dry out the samples, however, for previous experiments, we will recommend the use of the oven dry technique, from which we can rapidly remove any moisture that the sample might have in a very considerable rapid time, and produce more accurate results.
In a small reaction tube, the tetraphenylcyclopentadienone (0.110 g, 0.28 mmol) was added into the dimethyl acetylene dicarboxylate (0.1 mL) and nitrobenzene (1 mL) along with a boiling stick. The color of the mixed solution was purple. The solution was then heated to reflux until it turned into a tan color. After the color change has occurred, ethanol (3 mL) was stirred into the small reaction tube. After that, the small reaction tube was placed in an ice bath until the solid was formed at the bottom of the tube. Then, the solution with the precipitate was filtered through vacuum filtration and washed with ethanol. The precipitate then was dried and weighed. The final product was dimethyl tertraphenylpthalate (0.086 g, 0.172mmol, 61.42%).
The unknown bacterium that was handed out by the professor labeled “E19” was an irregular and raised shaped bacteria with a smooth texture and it had a white creamy color. The slant growth pattern was filiform and there was a turbid growth in the broth. After all the tests were complete and the results were compared the unknown bacterium was defined as Shigella sonnei. The results that narrowed it down the most were the gram stain, the lactose fermentation test, the citrate utilization test and the indole test. The results for each of the tests performed are listed in Table 1.1 below.
The goal of this two week lab was to examine the stereochemistry of the oxidation-reduction interconversion of 4-tert-butylcyclohexanol and 4-tert-butylcyclohexanone. The purpose of first week was to explore the oxidation of an alcohol to a ketone and see how the reduction of the ketone will affect the stereoselectivity. The purpose of first week is to oxidize the alcohol, 4-tert-butylcyclohexanol, to ketone just so that it can be reduced back into the alcohol to see how OH will react. The purpose of second week was to reduce 4-tert-butylcyclohexanol from first week and determine the effect of the product's diastereoselectivity by performing reduction procedures using sodium borohydride The chemicals for this lab are sodium hypochlorite, 4-tert-butylcyclohexanone
Enantiomers, a type of isomer, are non-superimposable, mirror images of each other. Diasteriomers, another type of isomer, are non-superimposable, non-mirror images of each other. Dimethyl maleate and dimethyl fumarate are diasteriomers, as they are not mirror images but instead vary in the orientation of the carbomethoxy groups around the double bond. Dimethyl maleate is the cis-isomer because both groups are on the same side and dimethyl fumarate is the trans-isomer because the two groups are on opposite sides. A bromine free radical mechanism was required for this conversion. First, energy from light is required to create two bromine free radicals from Br2. Then one of the free radicals attacks the double bond in dimethyl maleate, breaking it and creating a carbon radical on the other carbon. The bond then rotates and reforms, freeing the bromine radical and creating the trans-isomer, dimethyl fumarate. Bromine in this reaction is acting as a catalyst in this reaction and then cyclohexane is added at the end to neutralize the bromine free radicals. The activation reaction of the radical reaction is lower than the activation energy of the addition reaction, which is why it occurred more quickly. This reaction was successful because the percent yield was 67.1%, which is greater that 65%. It also demonstrated the expected principles, as the reaction did not occur without the presence of both light and bromine. The dimethyl fumarate had a measured boiling point of 100C to 103C, which is extremely close to the expected boiling point of 102C to
Alcohol, which is the nucleophile, attacks the acid, H2SO4, which is the catalyst, forming oxonium. However, the oxonium leaves due to the positive charge on oxygen, which makes it unstable. A stable secondary carbocation is formed. The electrons from the conjugate base attack the proton, henceforth, forming an alkene. Through this attack, the regeneration of the catalyst is formed with the product, 4-methylcyclohexene, before it oxidizes with KMnO4. In simpler terms, protonation of oxygen and the elimination of H+ with formation of alkene occurs.
In this lab 4-tert-butylcyclohexanone is reduced by sodium borohydride (NaBH4) to produce the cis and trans isomers of 4-tert-butylcyclohexanol. Since the starting material is a ketone, NaBH4 is strong enough to perform a reduction and lithium aluminum hydride is not needed. NaBH4 can attack the carbonyl group at an equatorial (cis) or axial (trans) position, making this reaction stereoselective. After the ketone is reduced by the metal-hydride, hydrochloric acid adds a proton to the negatively charged oxygen to make a hydroxyl group. The trans isomer is more abundant than the cis based on the results found in the experiment and the fact that the trans isomer is more stable; due to having the largest functional groups in equatorial positions.
This week’s lab was the third and final step in a multi-step synthesis reaction. The starting material of this week was benzil and 1,3- diphenylacetone was added along with a strong base, KOH, to form the product tetraphenylcyclopentadienone. The product was confirmed to be tetraphenylcyclopentadienone based of the color of the product, the IR spectrum, and the mechanism of the reaction. The product of the reaction was a dark purple/black color, which corresponds to literature colors of tetraphenylcyclopentadienone. The tetraphenylcyclopentadienone product was a deep purple/black because of its absorption of all light wavelengths. The conjugated aromatic rings in the product create a delocalized pi electron system and the electrons are excited
In order to separate the mixture of fluorene, o-toluic acid, and 1, 4-dibromobenzene, the previously learned techniques of extraction and crystallization are needed to perform the experiment. First, 10.0 mL of diethyl ether would be added to the mixture in a centrifuge tube (1) and shaken until the mixture completely dissolved (2). Diethyl ether is the best solvent for dissolving the mixture, because though it is a polar molecule, its ethyl groups make it a nonpolar solvent. The compounds, fluorene and 1, 4-dibromobenzene, are also nonpolar; therefore, it would be easier for it to be dissolved in this organic solvent.
Benzyl bromide, an unknown nucleophile and sodium hydroxide was synthesized to form a benzyl ether product. This product was purified and analyzed to find the unknown in the compound. A condenser and heat reflux was used to prevent reagents from escaping. Then the solid product was vacuum filtered.
Fire and thermal properties of PA 66 resin treated with poly-N- aniline- phenyl phosphamide as a flame retardant
The purpose of the experiment is to study the rate of reaction through varying of concentrations of a catalyst or temperatures with a constant pH, and through the data obtained the rate law, constants, and activation energies can be experimentally determined. The rate law determines how the speed of a reaction occurs thus allowing the study of the overall mechanism formation in reactions. In the general form of the rate law it is A + B C or r=k[A]x[B]y. The rate of reaction can be affected by the concentration such as A and B in the previous equation, order of reactions, and the rate constant with each species in an overall chemical reaction. As a result, the rate law must be determined experimentally. In general, in a multi-step reac...
In this experiment, four elimination reactions were compared and contrasted under acidic (H2SO4) and basic (KOC(CO3)3) conditions. The acid-catalyzed dehydration was done on 2-butanol and 1-butanol; a 2ᵒ and 1ᵒ alcohol, respectively. The base-induced dehydrobromination was performed on 2-bromobutane and 1-bromobutane; isomeric halides. The stereochemistry and regiochemistry of the four reactions were analyzed by gas chromatography (GC) to determine product distribution (assuming that the amount of each product in the gas mixture is proportional to the area under its complementary GC peak. The three butene products have been verified that they elute in the following order: 1-butene, trans-2-butene, and cis-2-butene.
Results and Discussion A film of COOH-functionalized nanotube suspense was dried on the working electrode of the SPE. Experiments were performed at the physiological pH of 7.4 because at this pH both the carboxyl group of the nanotubes and a hydroxyl group of ascorbic acid would be largely deprotonated.7 It was expected that the repulsion of like charges would prevent ascorbic acid from reaching the working electrode, and therefore would prevent the ascorbic acid from taking part in a redox reaction. While the application of the nanotube suspension reduced the effect of ascorbic acid at higher potentials in cyclic square wave voltammetry, it also resulted in the occurrence of a split anodic peak for the ascorbic acid at a potential near
The aim of this experiment was to investigate the affect of the use of a catalyst and temperature on the rate of reaction while keeping all the other factors that affect the reaction rate constant.
Introduction: Enzymatic reactions have played arguably one of the most important roles in the evolution of complex cellular life. By using proximity interactions to achieve thermodynamic favorability, enzymes are able to catalyze reactions that would have never occurred on a reasonable human time scale. This paper will highlight the importance of an enzyme aptly named “dihydrofolate reductase”, which has an integral role in an essential metabolic pathway. Spanning across thousands of organisms, this particular enzyme is utilized for the recycling of dihydrofolate (figure 1), a useful byproduct generated from thymidylate synthase catalysis. Figure 1: Structure of dihydrofolate (DHF)