barbier reaction: In a 50 mL round bottom flask that had a reflux condenser attachment, saturated ammonium chloride (5 mL), THF (1 mL), zinc powder (0.4 g), benzaldehyde (0.500 mL, 0.5225 g, 4.92 mmol), and allyl bromide (0.470 mL, 0.6533 g, 5.40 mmol) were charged with stir bar and stirred at room temperature for 45 minutes. Diethyl ether (10 mL) was added to the reaction mixture and stirred. The mixture was gravity filtered into a beaker that was topped with a watchglass. The filtrate was transferred to a separatory funnel and the organic layer was extracted with deionized water (10 mL) and diethyl ether (15 mL). The organic layer was placed into an Erlenmeyer flask and the aqueous layer was placed into a beaker, which was extracted with …show more content…
Every 5 minutes, a small amount of mixture was dissolved in acetone (0.5 mL) and was spotted onto a thin layer chromatography (TLC) plate, which contained an eluent mixture of ethyl acetate (2 mL) and hexanes (8 mL). The bezaldehyde disappearance was monitored under an ultraviolet (UV) light. Water (10 mL) was added after the reaction was complete, and vacuum filtrated with a Buchner funnel. Cold ethanol (5 mL) was added drop-by-drop to the dried solid and stirred at room temperature for about 10 minutes. Then, the solution was removed from the stirrer and place in an ice bath until recrystallization. The recrystallized product was dried under vacuum filtration and the 0.057 g (0.22 mmol, 43%) product was analyzed via FTIR and 1H NMR …show more content…
In a separate beaker, acetone (0.587 mL, 8 mmol) and benzaldehyde (1.63 mL, 16 mmol) were charged with a stir bar and stirred on a magnetic stirrer. The beaker mixture was slowly added to the Erlenmeyer flask and stirred at room temperature for 30 minutes. Every 10 minutes, a small amount of the reaction mixture was spotted on a TLC plate, with an eluent mixture of ethyl acetate (2 mL) and hexanes (8 mL), to monitor the decrease in benzaldehyde via a UV light. When the reaction was complete, it was chilled in an ice bath until the product precipitated, which was then vacuum filtrated. The filter cake was washed with ice-cold 95% ethanol (2 x 10 mL) and 4% acetic acid in 95% ethanol (10 mL). The solid was fluffed and vacuum filtrated for about 15 minutes. The 0.688 g (2.9 mmol, 36.8%, 111.3-112.8 °C) product was analyzed via FTIR and 1H NMR spectroscopies, and the melting point was obtained via
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 experimental Fischer esterification of 8.92g of acetic acid with 5.0g of isopentyl alcohol using concentrated sulfuric acid as a catalyst yielded 4.83g (65.3% yield) of isopentyl acetate. The product being isopentyl acetate was confirmed when the boiling point during distillation had similar characteristics to that of the literature boiling points2. Physical characteristics like color and smell also concluded a match of our product with what was intended. 1H-NMR spectroscopy analysis supported this claim due to the fact that the integration values and chemical shifts were comparable to isopentyl acetate. Lastly, infrared spectroscopy (IR) showed similar key characteristics of our product’s wavelengths to that of pure isopentyl acetate5.
Esters are defined as molecules consisting of a carbonyl group which is adjacent to an ether linkage. They are polar molecules which are less polar than alcohols but more so than ethers, due to their degree of hydrogen bonding ability. Most often derived from reacting an alcohol with a carboxylic acid, esters are a unique, ubiquitous class of compounds with many useful applications in both natural and industrial processes 1. For example, within mammals, esters are used in triglycerides and other lipids as they are the main functional group attacking fatty acids to the glycerol chain 2. A unique property of esters is their tendency to give off distinct aromas such as the scent of apples (Ethyl caprylate) and bananas (Isoamyl acetate). This is of a unique importance especially in industries that utilize flavors and aromas such as the tobacco, candy and alcohol industry. Consistent research is conducted in order to enhance and increase the effectiveness of esters in these products 3.
As shown in figure 2, the percentage of each isomeric alcohol in the mixture had been determined. The hydrogen atom on the carbon atom with the hydroxyl group appear at around 4.0 ppm for borneol and 3.6 ppm for isoborneol. The product ratio has been determined by integrating the peaks. A ratio of 6:1 for the Isoborneol/borneol ratio was expected and is validated by the calculations shown above, with isoborneol percentage at 83.82% and 16.17% of borneol. A CHCl3 group noted at around 7ppm and a CH2Cl2 at around 3.5ppm.
The goal of this lab is to exemplify a standard method for making alkyne groups in two main steps: adding bromine to alkene groups, and followed by heating the product with a strong base to eliminate H and Br from C. Then, in order to purify the product obtained, recrystallization method is used with ethanol and water. Lastly, the melting point and IR spectrum are used to determine the purity of diphenylacetylene.
The solvent should be easily removed from the purified product, not react with the target substances, and should only dissolve the target substance near it’s boiling point, but none at freezing. A successful recrystallization uses minimum amount of solvent, and cools the solution slowly, if done to fast, many impurities will be left in the crystals. Using the correct solvent, in this case ice water and ethyl acetate, the impurities in the compound can be dissolved to obtain just the pure compound. A mixed solvent was used to control the solubility of the product. The product is soluble in ethanol an insoluble in water. Adding water reduced solubility and saturates the solution and then the crystals
Data Table 3 indicates the observations from these tests. Though a control test for each test wasn’t prepared, due to the starting reagents being unattainable, the results clearly show that the product is unsaturated. An unsaturated compound means that there is/are bonds in its structure. The product was also analyzed by infrared spectroscopy and gas chromatography. The spectrums obtained allowed one to determine the composition of 1-methylcyclohexene; any impurities and excess products were observed as well. From the infrared spectrum, there is a little peak around 3300-3500 cm-1; this indicated a very little presence of alcohol in the product and thus, most of the alcohol has been successfully removed. If one compared the IR spectrum of the product to the starting material, 2-methylcyclohexanol, one could clearly see the change in peak size of the O-H stretch. The infrared spectrum of 1-methylcyclohexene also depicted a C-H stretch and an alkene functional group at 500-1500 cm-1 and 2932.54cm-1, respectively. From the gas chromatography spectrum (Data Table 4), the area percentages show that there were three products - peaks 22 through 24 - that were formed from the dehydration experiment. Nevertheless, there are two predominant products, as shown from their high percentages, 3-methylcyclohexene (~24%) and 1-methylcyclohexene
This experiment involves performing various techniques, including heating under reflux, separation, drying, distillation, gas chromatography (GC), infrared spectroscopy (IR spectroscopy), and nuclear magnetic resonance (1H NMR). Heating under reflux is important to overcome any activation barrier of energy that may be present in order to complete the reaction.
The purpose of this experiment is to determine the absolute configuration of an unknown chiral secondary alcohol using the competing enantioselective conversion (CEC) method. This method uses both R- and S- enantiomers of a chiral acyl-transfer catalyst called homobenzotetramisole (HBTM), in separate parallel reactions, and thin layer chromatography to identify the stereochemistry of the secondary alcohol, whether it be an R- or S- enantiomer. Quantitative analysis was performed using a program called ImageJ after the appropriate picture was taken of the stained TLC plate. The molecular structure of the unknown alcohol was identified using 1H NMR spectroscopy by matching the hydrogens to the corresponding peak.
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.
The percentage yield gained was 70% from the Fischer Esterification reaction, which evaluates to be a good production of yield produced as the reaction is known to be reversible where conditions such as the concentration of the reactants, pressure and temperature could affect the extent of the reaction from performing. These white crystalline crystals were tested for impurity by conducting a melting point analysis and taking spectrospic data such as the IR spectra, HNMR and CNMR to confirm the identification of the product. These spectrospic methods and melting point analysis confirmed the white crystalline crystals were benzocaine.
The goal of this experiment is to determine which products are formed from elimination reactions that occur in the dehydration of an alcohol under acidic and basic conditions. The process utilized is the acid-catalyzed dehydration of a secondary and primary alcohol, 1-butanol and 2-butanol, and the base-induced dehydrobromination of a secondary and primary bromide, 1-bromobutane and 2-bromobutane. The different products formed form each of these reactions will be analyzed using gas chromatography, which helps understand stereochemistry and regioselectivity of each product formed.
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.
Firstly, The Strata-X-A SPE cartridges prepared using 3 mL of methanol and equilibrated followed with 3mL of ultrapure water. Next, buckwheat honey samples of 30 g were thoroughly mixed with 120 mL of distilled water, and subsequently the solution was adjusted to pH 7.0 with with 5% ammonium (v/v).The buckwheat honey samples were centrifuged with 8000 × g for 10 min to dislodge the solid particles. The supernatants were was passed through the previously conditioned Strata-X-A SPE cartridges. After the samples was loaded, the columns were washed 4 mL of distilled water for Strata-X-A SPE cartridges to remove compounds of buckwheat honey that were not absorbed on the sorbents . Afterwards, the phenolic compounds were eluted with 5 mL of formic acid:methanol (1:9, v/v). The eluate was evaporated with 99.999% nitrogen and then the residue was redissolved in HPLC-grade methanol with 2% acetic acid with 98% methanol (2 ml). The resulting methanol extracts were filtered through a 0.22-μm filter (Millipore, Carrigtowhill, Cork, Ireland) and stored at 4 °C for further analysis by
The yield of the crude acetanilide was fair (98.45%). This was apparent from the melting point of the sample. The melting point of the crude acetanilide (116-123℃) had a fair comparison to the literature melting points (113-115℃(R1.). The yield of the recrystallized acetanilide was about half of the yield of the crude acetanilide. The recrystallized contained the key functional group. For instance,