V. Results and Discussion One of the objectives of this exercise is to synthesize acetylsalicylic acid (aspirin) from salicylic acid. The mechanism for this synthesis is through nucleophilic acyl substitution. Acetic anhydride was the acetylation reagent used with the salicylic acid. The mechanisms and the reaction involved in the synthesis are seen in the following figure. 1.00 gram of fine white salicylic acid powder was weighed in a clean, dry 125mL Erlenmeyer flask.
In this experiment, 293 mg of aldehyde was weighted for method 1 instead of 250 mg and. Although .7906 mg of phosphonium salt was added, this probably was not enough to complete the reaction. The only significant change throughout method was 1 was that the yellowish mixture became slightly lighter. However, it was found that after vacuum filtration, there was some white and yellow
The melting point of the product from the bromination of aniline was 119.8-121.90c, which is in the range of the melting point of 2,4,6-tribromoaniline, 120-1220c, as indicated on PubChem, Open Chemistry Database (pubchem.ncbi.nlm.nih.gov). This verified the formation of the major products. Overall, one can say that the experiment was
Power level optimization done on level 70, 80, 90 and 100. As time optimization of extraction is done at 15, 16, 17 and 18 minutes. Characterization of Alginate Characterization of sodium alginate was conducted to determine the physical and chemical properties of sodium alginate extraction results. Analysis of Water Content Analysis of water content is done by gravimetric methods AOAC (1990), by drying the sample at 105 oC alginate. The water content is determined based on the dry weight alginate that is a percentage of the dry weight of the initial weight.
One error that could have affected the percent yield is not filtering out all of the liquid from the filter paper in the funnel before setting it off to dry. This would have increased the final mass of the solid, not making it accurate. To stop this from happening again, the liquid could be drained more thoroughly until it fully stops dripping into the Erlenmeyer flask. Another error that could have affected the percent yield is the amount of trials performed. This would have made the results less accurate and made any errors change the final results even more.
Introduction The purpose of this experiment was to purify acetanilide that was contaminated with relatively small amounts of impurities using recrystallization. The success of recrystallization was dependent on a suitable solvent being chosen and proper recrystallization technique being carried out. The solvent chosen had to have a different polarity than that of the molecule of interest. The technique used was dependent on the solubility of the solvent at higher temperature and the solubility of the impurities at all temperatures. To analyze the acetanilide product of the reaction, 1H NMR and IR were used.
Theoritically, as the concentration of sodium alginate increases, the diffusion ability of the substrate into the beads will be decreased. This is because to more cross-linking at higher concentrations with more calcium binding sites. That is the reason why beads at high concentration appear bright white in color. At lowest concentration of sodium alginate, immobilization effectiveness will be higher. However, the gel at lowest concentration cannot withstand wear tear and very fragile.
Then calculate Percent Recovered on crystals formed, and preform melting point procedure. 2. You find that a solid substance you are trying to purify is very soluble in ethanol, but not very soluble in water. You decide that you are going to try to recrystallize it from a solvent pair, consisting of ethanol and water. is this decision based on sound rationale?
The melting point of the experimentally synthesized Aspirin product was found to be between 126-129 ˚C. This temperature range of initial to final melting point has a small and sharp temperature range of only 3˚C, which is within the acceptable limits of the 128-137˚C1 literature value for Aspirin (Acetylsalicylic Acid/2-acetoxybenzoic acid), if located slightly toward the beginning of the literature melting temperature range. Therefore, the narrow melting point range, which falls within the standard literature value range results, indicate the reliability purity of the sample. Had the melting point been higher than the literature value, but maintained a sharp melting point range, the compound could have still indicated a pure sample. A lower
Sample preparation is very important as some elements that are in the body can cause toxicity due to their concentration level. That is why the preparation of sample is based on the sample itself. Thus, atomic absorption spectroscopy is used to identify the level of concentrations that are present in the body. They are commonly used to analyze the presence of arsenic, mercury and lead concentration in the body. For example, atomic absorption spectroscopy is used to measure the level of sodium and potassium electrolyte present in the plasma.