Pages 96-98 in Chemistry 110 Lab Manual. Wilfrid Laurier University, ON, Canada. Abstract: The purpose of this experiment was to determine the level of purity by using the values for melting point and absorbance and chemically synthesizing aspirin by using phosphoric acid as a catalyst. Pure ASA crystals are isolated from the solution with a Hirsch Funnel that was used with a filter. The melting point of the pure ASA crystals were calculated in order to calculate of absorbance.
75°C, we got this temperature by filling the beaker with cold water and slowly adding boiling water from a kettle until we reached the right temperature. We then used a spatula to add the crude aspirin to the boiling tube and placed the tube in the beaker of hot water, and stirred it so that it will dissolve into the ethanol. We then poured the hot solution containing dissolved aspirin into approximately 40cm3 of water in a 100cm3 conical flask, the solid did not separate so we did not need to warm the contents of the flask in the water bath. We then let the conical flask cool slowly so that the white needles of aspirin separated. We did have crystals so we did
Four drops of acetone was then placed inside and the test tube was then shaken thoroughly. The procedure was then repeated to the formaldehyde, cyclohexanone, and benzaldehyde. To the acetone and formaldehyde test tubes, 3 drops of 6M sodium hydroxide was placed since no discoloration was observed after shaking the test tube. It was observed that the acetone turned purple to green to yellow to brown yellow after the sodium hydroxide was mixed with it while the formaldehyde turned yellow brown after the sodium hydroxide was added which indicated a positive result. The cyclohexanone produce red-orange precipitate while the benzaldehyde produced yellow
In the Oxidative fermentation tube the media was a differential media that helps determine whether specific bacteria can oxidize or ferment to metabolize glucose. Citrate test checks to see which bacteria could citrate as the only source of carbon. A positive test shows that an alkaline environment ia created and that the pH level rose. The color of the media changed from green to blue if its positive. The Bile Esculin agar test has its medium as selective and differential.
The Benedict’s test is useful for reducing sugars. Reducing sugars are a carbohydrate that can either be straight chains with an aldehyde group at the end or as ring forms with a ketone group (Hill, 1982). Monosaccharides and most disaccharides will reduce copper (II) sulfate. The Benedict’s solution contains cupric ions and the aldehyde groups at the end of the sugars will reduce the cupric ions to cuprous ions (Cu+). There will be a precipitate of copper (I) oxide when the cuprous ions combine with oxygen (Hill,
2 Preparation of benzhydrol from benzophenone (Reduction) Introduction: Reduction of benzophenone to benzhydrol carried out by using mild reducing agent sodium borohydride NaBH4 followed by acid hydrolysis. Reaction: Procedure: 1. Place 0.64 g of benzophenone and 4 mL of methanol in a 100 mL conical flask. 2. If necessary, warm the mixture to dissolve the benzophenone and then allow to cool at room temperature.
E. Discussion: In order to synthesize the polymer, Nylon 6,10, we had to complete a few steps to create the chemical reaction that combined sebacoyl chloride and hexamethylenediamine. First we measured the mass of the two graduated cylinders when they were empty, and measured it again after they were filled with sebacoyl chloride and hexamethylenediamine. We did this in order to find the measurements of the reactants. When we measured the graduated cylinder when they were emptied, one weighed at 10.99 grams while the other weighed at 10.94 grams. Even though they were the same kind of cylinder, I believe that a systematic error might have caused the second cylinder’s weight to be slightly affected, causing the weight to be lowered by 0.05 grams.
On the other hand, white solid paracetamol, 100ml beaker, and 15ml of hot water, 20ml warm water, and water bath were used for the recrystallization purification technique. Evaporating dish, cold water, stirring rod, watch glass, small beaker, oven, cotton wool, and tissue were also employed in the recrystallization purification method. Method Recrystallization purification technique A portion of crude paracetamol sample was transferred into a 100ml beaker. To it, 10ml of hot water was added to dissolve it. Cotton wool was placed into the funnel; this was followed by pouring hot water onto the cotton wool before filtering the dissolved paracetamol crude solution to remove any insoluble materials.
The antioxidant activity of the extracts was measured on the basis of the scavenging activity of the stable DPPH free radical (as cited in Dong et al., 2014). Evaluation of antioxidant activity of astaxanthin through DPPH assay was modified according to the procedures reported by Lewis (2012). 12 mls of 0.1 mM DPPH solution with methanol was prepared. A measurement of 0.005 g of DPPH was added to 12 mls of methanol which was measured with a graduated cylinder into a small foil-wrapped flask. A number of 11 two ml microcentrifuge tubes were assembled and was labeled as: Tubes 1a-c through 3a-c: Product Extract Dilution 1 through 3 (repeat three times for 9 tubes), Tube 4: Positive control, α-tocopherol and Tube 5: Negative control, solvent only.
Wash ether layer with saturated sodium chloride solution and retain ether layer. In a small 125ml Erlenmeyer flask, dry the ether solution over anhydrous calcium chloride. Add sufficient calcium chloride so that it no longer clumps to pellets added earlier on the bottom of the flask. Remove the solvent using a rotary evaporator and weigh product. Results 1 mole of benzoic acid (C6H5COOH = 122.12grams) reacts with 1 mole of methanol (CH3OH = 32grams/mole) to produce 1 mole of methyl benzoate (C6H5COOCH3 = 136.15grams) and 1 mole of water.