Nucleophilic Substitution Reactions Lab

The aim of this experiment was to prepare a buffer for an unknown amino acid with the goal of identifying the unknown amino acid. The objective was to use the Henderson Hasselbalch equation to determine the buffer capacity, and to use the pKa values and molecular weight, to identify the unknown amino acid through acid-base titrations. Titration was done on the unknown amino acid with a strong acid and base while titration was done on NaCl, which acted as a blank for identifying the unknown amino acid and was used to find the true titration curve of the amino acid. The pka values were found to be 1.95 and 8.88, and the molecular weight 133.98 g/mol. Moles extrapolated from the titration curve were used to find the molecular weight of the unknown amino acid, along with the pkas and the pI. This information when compared to the literature values of Gly, L-ala, L-ser, and L-asp (of which the unknown was one of) led to the conclusion that the identification of unknown C was likely to be L-Aspartic Acid.

To make sure this doesn’t happen, there needs to be more trials to increase the precision of the results. Abstract The purpose of the lab was to determine what each of nice substances was based upon how they reacted with other chemicals as well as their pH levels. By using the given clues, the reaction with Litmus paper, and the precipitates formed by different mixtures, the chemicals were identified. Substance 1 was found to be BaCl , substance 2 was determined to be NaOH, and substance 3 was labeled as CuSO .

This aqueous solution was then heated until all the dichloromethane evaporated off. An error could have occurred at this point in the experiment if the hot plate was too hot. If the hot plate was set above the boiling point of the ketone, the ketone could have evaporated of along with the dichloromethane. This would result in a lower percent yield of the ketone. To prevent this from happening, the hot plate should not exceed 130˚C, so no matter what ketone was isolated, it would not evaporated off.

One of the reactions you observed resulted in this product: NaCl + H2O + CO2 (g)? What well did this reaction occur in? Describe how the observations for this reaction support your answer. B BoldI ItalicsU Underline Bulleted list Numbered list Superscript Subscript70 Words A reaction I observed in number 1.)

The anthraquinone dye experiment has the purpose to identify the anthraquinone dyes from unknown mixture by using thin layer chromatography (TLC) of the unknown fraction. An anthraquinone is an aromatic organic compound obtained by the oxidation of anthracene. To separate the compounds in the mixture, column chromatography and thin layer chromatography uses portioning of a sample between a stationary solid phase and a liquid mobile phase. As the stationary phase, they use either silica gel or alumina, and organic solvents as the mobile phase. In order to accomplish the experiment, an unknown which is a solution of at least two anthraquinone dyes will be used.

This problem could have arisen from an overly dilute extract used when running the TLC. Prior to conducting TLC, the extracts S2 and S3 were used in the UV-vis spectroscopic analysis. Failing to consider the use of the samples for TLC afterwards, huge proportions of both extracts were disposed off after the spectroscopic analysis. Even though the remaining extract volumes were concentrated by evaporating off the solvent, the number of moles of compounds present were still not concentrated enough for clear visible spots to be obtained from the TLC

[5] synthesized Mannich bases of isoxazolines derivatives by the condensation reaction of substituted acetophenone with substituted aldehydes in presence of alcoholic NaOH via chalcones intermediate. A palumbopiccionello, et. al[6] reported the synthesis of isoxazoline derivatives through Boulton –Katrizky rearrangement of 1, 2, 4, oxadiazoles. R. Bhimwal etal.[7] described the synthesis of isoxazolines via cyclisation of substituted chalcone intermediates in the presence of hydroxylamine hydrochloride and screened them for antimicrobial activity. Tejaskumar et al.[8] proposed the synthesis of isoxazolines derivatives and screened them for antimicrobial activity.

[22]. Before solution application, the HPTLC plates were sprayed with 10% (w/v) disodium ethylene diaminetetraacetic acid (Na2EDTA) solution in which the pH had been adjusted to 4 using glacial acetic acid. This Na2EDTA solution helps to avoid binding of the tetracyclines with trace metals in the adsorbents used [23]. Since OTC and TC have similar chemical and physicochemical properties they form chelate complexes with metal ions and bind with proteins and silanol groups in the stationary phase. These undesirable properties have been controlled by the use of EDTA for plate treatment [23].

This catalyzed the reaction which contributed to the oxidized form of naphthol which in turn formed purple precipitate which helped in determining the location of the human serum albumin. Therefore, absence of purple bands on the nitrocellulose membrane (Figure 3) proved that protein was not fully transferred to the nitrocellulose membrane. Lack of transfer of protein to the nitrocellulose membrane maybe due to the inaccurate rolling of the rod to collect the proteins or maybe the washings were done too many

>Unit of parts per million range. >Environmental distraction, especially water vapor. > Strong electrical fields, rapid variation in temperature at the detector and naturally occurring compounds may affect instrumental signal Gas Chromatography/Mass Spectroscopy: The gas chromatography device is generally a reliable analytical instrument.

The recrystallization was very effective for our recrystallized vanillin because we were able to obtain a similar literature melting range of the vanillin for our recrystallized vanillin. For our unknown compound B8, the recrystallization was effective. However, our recrystallized unknown still have some impurities in it, so that’s why our recrystallized unknown started to melt at a lower temperature. 4.

In this lab, three unknown compounds were separated from a mixture and identified by melting point. Unknown mixture #124 has components of acid, base and neutral compound. The compounds were identified by melting point and matched up with the known melting points from a given list. In order to identify the compound it was important to separate by dissolving the mixture in an organic solvent which was not soluble in water, and then extracting the solution first with HCl, and then dilute sodium hydroxide solution. From the separation mixture, the aqueous layer were obtained and labeled as TT-1 (base), TT-2(acid) and TT-3 (neutral) in three different test tubes for later recovery.

After finding the Rf values of the four known compounds, solvent 1 (99.5% ethyl acetate/0.5% acetic acid) was chosen, due to the wide range of results, for the remaining experiments. Ibuprofen, our known tablet, gave a similar Rf value to our previous results for Ibuprofen. For Anadin extra, there were three compounds identified as Caffeine, Paracetamol and Aspirin as the Rf values of the drug were close to the values of these three compounds in the first part of the practical. For both of these known drugs, the Rf values acquired were close to my predictions before the experiment. For the unknown powder, we obtained Rf values of 0.52 and 0.76 so we believe that the unknown powder contains Aspirin and Ibuprofen.

The goal of this experiment was to isolate three different molecules (acidic, basic, and neutral) from a mixture and identify their molecular structure. This was accomplished by using acid/base liquid extraction and H NMR analysis. The neutral component of the unknown mixture #191 was fluorenone. This was evident due to an H NMR spectra that had a high presence of hydrogen signals in the 7.2- 7.7 ppm range. Chemical shift values for fluorenone stated in the lab manual were 7.27, 7.47, 7.48, and 7.6 (CITE), indicating that the corresponding H NMR spectra for the neutral unknown is of this chemical.

Introduction: The objective of the experiment is to determine the limiting reagent in a chemical reaction. The principles of stoichiometry and limiting reagents will be used to predict the amount of product formed. The amount of product formed and the change in the color of the solution upon mixing of two reactants are being used to predict the limiting reagent and calculate the theoretical yield in grams. My hypothesis was that with the reaction of the zinc with the copper sulfate solution that it would dissolve the zinc to determine the limiting reagent.