In this experiment, TLC, IR, and melting point ranges were observed and used to estimate the purity of a solid, which was benzocaine. The percent recovery of the benzocaine was 23.5 %, which indicates how much of the benzocaine component was in the mixture. The percent recovery of the benzoic acid was 44%. Based on the percent recovery of each sample, the amount of original sample that was lost in the extraction and work-up was 32.5 %. Based on the melting point ranges of the isolated compounds, the purity can be estimated. Based on the literature value of the Benzoic acid which was determined from the Sigma-Aldrich chemistry book available in the lab, to be 121-125 ̊C, the isolated benzoic acid compound was found to be pure because the observed melting …show more content…
Based on the Rf values, the isolated samples can also be considered pure. The Rf value for the reference benzoic acid was calculated to be 0.33, and the value of the benzoic acid was 0.52, there is a difference in these two values, but this was due to smearing or streaking, but there are similarities in the spots. The Rf value for the reference benzocaine was calculated to be 0.31, and the Rf of the benzocaine was 0.29, which indicated very similar vales, which indicated that the isolated sample was indeed pure, and very similar to the reference compound. When comparing figures 4 and 5, the peaks of the IR spectrum of benzocaine can be observed to determine if the solid is pure. The peaks of the IR spectrum obtained through testing does match the reference IR spectrum. Some examples of the matching frequency, wavelength values are the following; (IR through testing, Reference); (1681.82,~1700), (1126.27,~1120), and (1173.08,~1175). Also, compared to the compound formula, and the IR spectrum, the bonds that correlate to the peaks are as follows; C-H stretches at ~3300, N-H stretch at ~3400, C=O stretch at ~2700, and C-O stretch from ~1000 to
The purpose of the Unknown White Compound Lab was to identify the unknown compound by performing several experiments. Conducting a solubility test, flame test, pH paper test, ion test, pH probe test, conductivity probe test, and synthesizing the compound will accurately identified the unknown compound. In order to narrow down the possible compounds, the solubility test was used to determine that the compound was soluble in water. Next, the flame test was used to compare the unknown compound to other known compounds such as potassium chloride, sodium chloride, and calcium carbonate. The flame test concluded that the cation in the unknown compound was potassium. Following, pH paper was used to determine the compound to be neutral and slightly
The primary goal of this laboratory project was to identify an unknown compound and determine its chemical and physical properties. First the appearance, odor, solubility, and conductivity of the compound were observed and measured so that they could be compared to those of known compounds. Then the cation present in the compound was identified using the flame test. The identity of the anion present in the compound was deduced through a series of chemical tests (Cooper, 2009).
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
A weak peak was at a position between 1600-1620 cm-1 can also be seem in the IR, which was likely to be aromatic C=C functional group that was from two benzene rings attached to alkynes. On the other hand, the IR spectrum of the experimental diphenylacetylene resulted in 4 peaks. The first peak was strong and broad at the position of 3359.26 cm-1, which was most likely to be OH bond. The OH bond appeared in the spectrum because of the residue left from ethanol that was used to clean the product at the end of recrystallization process. It might also be from the water that was trapped in the crystal since the solution was put in ice bath during the recrystallization process. The second peak was weak, but sharp. It was at the position of 3062.93 cm-1, which indicated that C-H (sp2) was presence in the compound. The group was likely from the C-H bonds in the benzene ring attached to the alkyne. The remaining peaks were weak and at positions of 1637.48 and 1599.15 cm-1, respectively. This showed that the compound had aromatic C=C function groups, which was from the benzene rings. Overall, by looking at the functional groups presented in the compound, one can assume that the compound consisted of diphenylacetelene and ethanol or
The two diastereomeric products that are made do not separate well by TLC. In order to see the two isomers, it is necessary to convert the products into derivatives. To more easily identify the stereoisomers produced in the reduction of benzil, hydrobenzoin is converted to acetonide by reacting with 2-methoxypropene and acid. The cis and trans isomers of these derivatives have different Rf values on TLC making it possible to identify the stereoisomers that have been prepared. The solution is compared with syn and anti acetonide on two different TLC plates.
The actual melting point of benzoic acid is known to be 122.4°C. Also, looking at Table1, the percent yield is shown to be 44.9%. The percent yield is how much product was recovered after the reaction was carried out. The percent yield can be used to explain why the melting point observed in the experiment didn’t match the known melting point. Obtained melting points are generally lower than the literature value melting points of a substance due to the number of impurities present in the obtained product. The percent yield of 44.9%, validates that the product could have had some impurities present, and thus the lower melting
This experiment sought to utilize melting point, boiling point, infrared (IR) spectroscopy, and the index of hydrogen deficiency (IHD) to identify the structures of two unknown compounds. To ensure the successful identification of the unknowns, the molecular formula for each compound was found first. What the molecular formula does is that it allows chemists to identify elements present in a compound as well as the quantity of each element. The issue with this is that there are various compounds that share the same molecular compound yet are different in reactivity and connectivity. To resolve this problem, other measures such as finding functional groups based on IR spectroscopy, determining the boiling or melting point of a compound, and identifying the bond/ring structures using IHD are taken.
Ensure gloves are worn at all times when handling strong acids and bases within the experiment of the preparation of benzocaine. 4-aminobenzoic acid (3.0g, 0.022 moles) was suspended into a dry round-bottomed flask (100cm3) followed by methylated sprits (20 cm3). Taking extra care the concentrated sulphuric acid of (3.0 cm3, 0.031 moles) was added. Immediately after the condenser was fitted on, and the components in the flask were swirled gently to mix components. It should be ensured that the reactants of the concentrated sulphuric acid and the 4-aminobenzoic acid were not clustered in the ground glass joint between the condenser itself and the flask. In order to heat the mixture to a boiling point, a heating mantle was used and then further left for gently refluxing for a constituent time of forty minutes. After the duration of the consistent forty minutes the rou...
The theoretical yield of the m-nitrobenzoate was de-termined to be 4.59 grams. The actual amount of crude product was determined to be 3.11 grams. The percent yield of the crude product was determined to be 67.75 %. The actual amount of pure product formed was found to be 4.38 grams. The percent yield of the pure product was determined to be 95.42%. Regarding the thin layer chromatography, the line from the solvent front was 8 centimeters.
The conical vial was placed in a small beaker and allowed to cool to room temperature. The mixture was Cooled thoroughly in an ice bath for 15-20 minutes and crystals collected by vacuum filtration on a Hirsch funnel. The vial was rinsed with about 5 mL of ice water and transferred into to the Hirsch funnel and again washed with two additional 5mL portions of ice water. Crystals were dried for 5-10 minutes by allowing air to be drawn through them while they remained on the Hirsch funnel. The product was transferred to a watch glass plate and allow the crystals to dry in air. Crude acetaminophen product was weighed and set aside a small sample for a melting point determination and a color comparison after the next step. Calculation of the percentage yield of crude acetaminophen (MW = 151.2). was done and recorded in the lab notebook.
Based on the observed melting point range, the sample of Benzoic Acid was pure. The melting point range of the product read 122.5°C -123.2°C. The melting point fell within the melting point range of pure Benzoic Acid (121°C – 125°C), indicating both products are similar to one another. The melting point range of the sample was also very narrow (<1°C), indicating the sample was not comprised of any major impurities. Based on the observed melting point range, the sample of 2-naphthol was relatively pure. The sample’s melting point range (121.3°C – 122.6°C) was slightly below the range of pure 2-naphthol (123°C – 124°C), indicating the possibility of impurities. Yet, the melting point range of the sample was very narrow (≅1°C), indicating the sample was not comprised of any major impurities. Based on the observed melting point range, the sample of 1,4 – dimethoxybenzene was very impure. The sample’s melting point range (116.5°C – 120.9°C) was much higher than pure 1-4 dimethoxybenzene (58°C – 60°C), indicating major impurities within the sample. The wide observed melting point range also indicates a depressed melting point, leading to the conclusion that the compound is
It was clear that synthesis was of benzhydrol was taking place as the formation of the addition complex, which formed a white gunk, was present. Also, it was possible to tell the synthesis was occurring when the white gunk from the addition complex was consumed during the acid workup. During the extraction of the products there was two layers forming which also indicated that synthesis had occurred, and trace amount of white bits of product were found in the waste beaker which also indicated that synthesis occurred.
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.
After the some time, we filter it through a Büchner funnel before it is recrystallized and filtered again. The mass was recorded as it was dry. By adding sodium carbonate, we will now test whether what obtained is benzoic acid or not, because one can observe bobbles if it is an acid. After that we burn it to test if it is aromatic.
When benzoic acid paired with 1.0 M NaOH, it was observed that both compounds were soluble. Upon the addition of 6.0 M HCl into this solution, benzoic acid became insoluble. Benzoic acid was also insoluble in 1.0 M HCl. Ethyl 4-aminobenzoate was found to be insoluble in 1.0 M NaOH and soluble in 1.0 M HCl. But then, after adding 6.0 M NaOH into the test tube C (mixture of ethyl 4-aminobenzoate and 1.0 M HCl), a white powdery solid (undissolved compound) was formed. These demonstrate that both the acid and base became more soluble when they were ionized and less soluble when they were