The purpose of the experiment was to use the method of simple distillation to separate hexane, heptane, and a mixture of the two compounds into three different samples. After separation, gas chromatography determined the proportions of the two volatile compounds in a given sample. After obtaining three fraction samples of hexane, heptane, and the mixture of the two into three separate vials, gas chromatography was performed to find the relative composition of each of the three samples. For the first vial containing pure hexane, a ratio of 66.26% hexane to 33.74% heptane was determined and had a boiling point range of 69.2-76.4°C during simple distillation. The second vial containing both hexane and heptane was determined to have the ratio of 40.15% hexane and 59.85% heptane and a boiling point range of 78.2-89.0°C. The third vial containing only heptane had a …show more content…
ratio of 8.22% hexane to 91.78% heptane and a boiling point range of 90.4-97.7°C. A group who performed the same experiment, but with octane and hexane had the ratios of 97.63% hexane to 2.37% octane, 23.23% hexane to 76.77% octane, and 21.07% hexane to 78.93% octane, for vials 1, 2, and 3 respectively. During the experiment, due to time restrictions, a fourth sample composed of the residue remaining in the conical vial after simple distillation.
Therefore, the gas chromatography could not be performed to determine its composition. The ratio of the three samples obtained, were not all accurate. The first sample, of pure hexane should have had a ratio close to 100% hexane to 0% heptane. The second ratio should have been close to 50% hexane to 50% heptane and the third should have been the reverse of the first sample, with 0% hexane to 100% heptane. The boiling point of hexane is around 65°C and the boiling point of Heptane is 100°C. The first sample’s error could have occurred due to the late extraction of the sample. When the boiling point was reached, the extraction of the sample from the distillation vial should have occurred immediately, not doing so caused some of the vapors from heptane to be included into the first sample. This could be prevented next time by lowering the heat of the Variac transformer, which would have allowed for the heating of the compound to be slower than what it was
initially. From the experiment, I learned how to perform the method of simple distillation of two volatile compounds with relatively similar boiling points as well as how to perform gas chromatography Due to the error performed when extracting hexane, my experimental goal was not completely obtained, but could have been if the extraction’s performance was accurately.
Some possible errors raised during the synthesis and spectrometric analysis of TPCP include the insufficient mixing of the hexane and TPCP, in which will result in the low absorbance of the compound. Additionally, the low yield is contributed from the loss of product during filtration.
Then the reaction tube was capped but not tightly. The tube then was placed in a sand bath reflux to heat it until a brown color was formed. Then the tube was taken out of the sand bath and allowed to cool to room temperature. Then the tube was shaken until a formation of a white solid at the bottom of the tube. After formation of the white solid, diphenyl ether (2 mL) was added to the solution and heated until the white solid was completely dissolved in the solution. After heating, the tube was cooled to room temperature. Then toluene (2 mL) was added to the solution. The tube was then placed in an ice bath. Then the solution was filtered via vacuum filtration, and there was a formation of a white solid. Then the product was dried and weighed. The Final product was hexaphenylbenzene (0.094 g, 0.176 mmol,
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
2-ethyl-1,3-hexanediol. The molecular weight of this compound is 146.2g/mol. It is converted into 2-ethyl-1-hydroxyhexan-3-one. This compounds molecular weight is 144.2g/mol. This gives a theoretical yield of .63 grams. My actual yield was .42 grams. Therefore, my percent yield was 67%. This was one of my highest yields yet. I felt that this was a good yield because part of this experiment is an equilibrium reaction. Hypochlorite must be used in excess to push the reaction to the right. Also, there were better ways to do this experiment where higher yields could have been produced. For example PCC could have been used. However, because of its toxic properties, its use is restricted. The purpose of this experiment was to determine which of the 3 compounds was formed from the starting material. The third compound was the oxidation of both alcohols. This could not have been my product because of the results of my IR. I had a broad large absorption is the range of 3200 to 3500 wavenumbers. This indicates the presence of an alcohol. If my compound had been fully oxidized then there would be no such alcohol present. Also, because of my IR, I know that my compound was one of the other 2 compounds because of the strong sharp absorption at 1705 wavenumbers. This indicates the presence of a carbonyl. Also, my 2,4-DNP test was positive. Therefore I had to prove which of the two compounds my final product was. The first was the oxidation of the primary alcohol, forming an aldehyde and a secondary alcohol. This could not have been my product because the Tollen’s test. My test was negative indicating no such aldehyde. Also, the textbook states that aldehydes show 2 characteristic absorption’s in the range of 2720-2820 wavenumbers. No such absorption’s were present in my sample. Therefore my final product was the oxidation of the secondary alcohol. My final product had a primary alcohol and a secondary ketone
Triphenylmethyl Bromide. A 400 mL beaker was filled with hot water from the tap. Acetic acid (4 mL) and solid triphenylmethanol (0.199 g, 0.764 mmol) were added to a reaction tube, with 33% hydrobromic acid solution (0.6 mL) being added dropwise via syringe. The compound in the tube then took on a light yellow color. The tube was then placed in the beaker and heated for 5 minutes. After the allotted time, the tube was removed from the hot water bath and allowed to cool to room temperature. In the meantime, an ice bath was made utilizing the 600 mL plastic beaker, which the tube was then placed in for 10 minutes. The compound was then vacuum filtered with the crystals rinsed with water and a small amount of hexane. The crude product was then weighed and recrystallized with hexane to form fine white crystals, which was triphenylmethyl bromide (0.105 g, 0.325 mmol, 42.5%). A Beilstein test was conducted, and the crystals produced a green to greenish-blue flame.
...bromebutane. Unfortunately, our group was only able to obtain the chromatograph for 2-bromobutane and the rest of the three chromatographs were provided by our T.A. Some possible reasons why the chromatographs for 2-butanol, 1-butanol, and 1-bromobutane were unable to be displayed properly is due to the malfunction of the syringes. If the syringe is not air-tight, the gaseous products can escape before being inserted into the injection port. In addition, the collection tube may have had a minor gas escape from the rubber septum, resulting in less concentrated gaseous products being inserted into the injection port. A possible solution is sealing the collection tube with parafilm. All in all, the provided data chromatographs and the rendered chromatograph by the 2-bromobutane in the lab session did match the expected results for the distribution of gaseous products.
Since 1-octanol was the least polar among 3 alcohols used in this part, so it was found to be insoluble in water but soluble in hexane. This was due to the longer chain of carbons makes compounds more hydrocarbon-like.
The percentage of crude acetaminophen was 77.78%. The infrared spectrum of synthesised acetaminophen was similar to the USP grade acetaminophen. The functional groups and type of bonds in acetaminophen were identified. The NH bond stretching at wavenumber 3325.81 cm-1 and 3325.44 cm-1 in USP grade acetaminophen and synthesised acetaminophen. The bending of NH bond formed a band around 1610 cm-1. The presence of carbonyl group in both synthesised and USP grade acetaminophen gave a peak at wavenumber 1663.50 cm-1 and 1664.71 cm-1. Acetaminophen is para-disubstitution, it formed a peak around wavenumber 837cm-1. There were two small broad peaks found in both spectrum around wavenumber 3160 cm-1 to 3210 cm-1, this indicated the presence of OH group in the solutions. The melting point of synthesised and USP grade acetaminophen were 160 ℃-170 ℃ and 160 ℃-173 ℃. Both of these acetaminophen do not comply with the USP monograph melting point which is 168 ℃ to 172 ℃. This indicated there are some impurity presence in both of the synthesised and USP grade acetaminophen. The maximum wavelength of synthesised acetaminophen was 244.0 nm which was close to the wavelength of USP grade acetaminophen. The retention factor of synthesised and USP grade acetaminophen were 0.93 and 0.94. This showed that the purity of synthesised acetaminophen was similar to the USP grade acetaminophen. The absorbance value of synthesised and USP grade
In this lab, Thin Layer Chromatography was used to identify the components of a certain drug. To do this, the compound in question, Motrin was tested against six standards in three different solvents. The three solvent were hexanes, ethyl acetate, and 75% ethyl acetate and 25% hexane; the solution of 75% ethyl acetate and 25% hexane was determined to be the best solvent. This is due to the larger variance in RF values. The six standards that Motrin was tested against were Aspirin, ibuprofen, acetaminophen, naproxen sodium, caffeine and a caffeine and ibuprofen mixture. To determine which standard was present in the chosen drug, the retention factors, or RF, were calculated. A UV light was also used to see the distance each sample traveled in
The joints were greased well to prevent vapor loss. 15 mL of the sample used and two boiling chips were placed in the distilling flask. The flask was heated with a hotplate in an oil bath. In separate, numbered, and calibrated test tubes, 0.5 mL of the distillate were collected while the temperature was recorded when each fraction was collected. The distillation was stopped when the temperature reached above 90˚. The set-up was cooled and the remaining liquid in the distilling flask were poured into a graduated cylinder. The volume was recorded. The temperature reading versus the volume of distillate were now plotted. The percent ethanol was computed.
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.
The purpose of these lab was to help students understand the chromatographic techniques of column chromatography and Thin layer chromatography. Column chromatography is used to help students understand the relationship between eluting power and polarity. Eluting power is defined as the ability of the mobile phase to move a substance from stationary phase. The polarity of the solvent used in the lab can be described as Methanol> acetonitrile>acetone>ethyl acetate> hexane in decreasing order. Since Methanol and acetonitrile are more polar, they will easily separate methylene blue and methyl orange wh while other solvents will take longer time to separate. In the case of hexane, on the dyes did not separate at all and they slightly separated
Briefly, 2-10 mg fish food was spiked 100 µL with D12-benzo(a)pyrene internal standard (AccuStandard, New Haven, CT, USA) and extracted by sonicating 10 min in 0.5 mL 1:1 hexane:acetone followed by centrifugation for 1 min at 10,000 x g. The organic layer was transferred to an autosampler vial and the pellet extracted twice more, combining the organic fractions. Extracts were concentrated under N2 to 200 µL, exchanged into hexane and spiked with D12-pyrene (AccuStandard) as a secondary internal standard to calculate recoveries of D12-benzo(a)pyrene, and diluted to 1 mL with hexane. Triplicate blanks containing no fish food were processed along with samples. Samples were analyzed by gas chromatography-mass spectrometry (GC-MS) in electron ionization mode using selected ion monitoring (Agilent 7890A GC, 5975C MS; Agilent, Wilmington, DE, USA). Analytes were separated using an Agilent DB-5ms column (0.25 mm ID 30 m; 0.25 µm film), 2 µL injection, and thermal gradient (80°C for 1 min; 2°0C/min to 300°C, 300°C for 10 min) at 1.2 mL/min constant flow. BaP and the mass-labeled internal standards were detected at 252 and 264 m/z, respectively. Recoveries of D12-benzo(a)pyrene were 95±3%, and the method detection limit was 0.07
Gas-Liquid Chromatography utilizes the principle of the difference in solubility of the components of gas mixture (vapourized sample) in the non-volatile liquid phase. Volatile sample to be analyzed is vaporized and blown through heated column by inert gas carrier such as helium. The more sol...
Ground sample were collected in air tight container separately for further analysis at room temperature. The prepared sample were extracted in absolute methanol and 80% methanol in orbital shaker for 4 hrs at 45°C. In extraction process 3 g of prepared sample were weigh in universal bottle and 75 ml solvent was added. After extraction process supernatant were collected for further analysis.