Preview

Recrystallization of Pure Phthalic Acid, Benzoic Acid and Napthalene

Good Essays
Open Document
Open Document
415 Words
Grammar
Grammar
Plagiarism
Plagiarism
Writing
Writing
Score
Score
Recrystallization of Pure Phthalic Acid, Benzoic Acid and Napthalene
Richard Trinh
5/29/13
TA: Jingy Wang
Experiment #4
Recrystallization of Pure Phthalic Acid, Benzoic Acid and Napthalene
Introduction
Recrystallization is a important method in purifying organic compounds which are solid. It is an effective method that is important to be familiar with that is essential in the industrial chemical world. This experiment will allow students to be familiarized with the technique of recrystallization by working with phtalic acid, benzoic acid and naphthalene from appropriate organic solvents.
Experimental Method 1. Gather 200mg of phtalic acid, add drop wise with Pasteur pipette. 2. Set up boiling apparatus and cork test tube then clamp when cooling 3. Recrystallize at 22oC in ice, stir with pipette and expel air 4. In test tube add ethanol to remove H2O. 5. Scrape out crystals and determine % recovery. 6. Gather 50mg of Benzoic acid. 7. Recrystallize same method as Phthalic acid 8. Determine percent recovery. 9. Recrystallization of Napthalene, by adding 1.0g of solid. 10. Add 3mL methanol and boiling stone. 11. Heat to boil and add dropwise methanol till it dissolves solid. 12. Cool in ice and filter, was with 30:7 ratio mix of methanol and water. 13. Determine percent recovery.
Chemicals Used 1. Phthalic Acid

2. Benzoic Acid

3. Naphthalene

Results | Melting Point (oC) | Weight (g) | % Recovery | Phthalic Acid | 175.5 | .35 | 67.5 | Benzoic Acid with H2O | 117.5 | .045 | 95 | Benzoic Acid with Methanol | 118 | .12 | 24 | Napthalene | 75.5 | .23 | 22.9 |
Calculations:
% recovery = (weight/original weight) x 100%
Discussion
The melting points for the lab results were quite close to the literature values. The first method of recrystallization was more effective than the 2nd method using methanol. The percent recovery of benzoic acid using water is recorded at a high of 95% recovered. The lower percent recoveries were possibly due the lab



References: Nist Chemistry Webook Database webbook.nist.gov Experimental Organic Chemistry- Laboratory Manual. Solomon W. Chemical and Physical Properties Database www.dep.state.pa.us/physicalproperties/‎

You May Also Find These Documents Helpful

  • Satisfactory Essays

    Organic Lab 2583-4

    • 503 Words
    • 3 Pages

    The purpose of this lab is to purify solids contaminated by relatively small amount of impurities by a technique called Recrystallization. Compounds that have different solubility at different temperature usually can be recrystallized.…

    • 503 Words
    • 3 Pages
    Satisfactory Essays
  • Satisfactory Essays

    Chem 1211K Lab Report

    • 1855 Words
    • 18 Pages

    The identification of the melting point of the organic acid was done to find another characteristic of the acid and to test the purity of the recrystallized pure acid. A 2-4 mm layer of unknown sample was placed into a capillary tube sealed on one end. Then the capillary tube was inserted into the side a Bibby Sterlin device. The plateau was set to 200°C on the melting point apparatus. Once the plateau temperature was reached, the sample was watched carefully. When the sample first began to melt and when it was fully melted was recorded. These numbers were the range of the melting point. A slow melting point of the unknown organic acid and a standard sample was completed next. A new plateau was set about 10°C lower than the observed melting point of the unknown sample. This time once the plateau was reached, the heating was no more than 1°C per minute. This gave a much more accurate read of both melting points. If the standard did not melt in the range listed on the label of the bottle, that meant the machine was not working properly. The standard sample and the unknown organic acid melted in their appropriate ranges.…

    • 1855 Words
    • 18 Pages
    Satisfactory Essays
  • Good Essays

    During the reflux period, there have not been any signs of errors; the reflux distillation process occurred smoothly. Once reflux distillation was completed, the mixture was cooled to room temperature, then extracted thrice by a separatory funnel. Before any extractions proceeded though, the mixture already had two distinct layers – a top dark brown layer, and a bottom light yellow layer. This mixture was extracted with 9M sulfuric acid, and the aqueous layer, containing butanol, sulfuric acid, and water, was removed and discarded. The organic layer, consisting of the n-butyl bromide, went through a second extraction with water. This resulted in an organic layer of n-butyl bromide and water and an aqueous layer of water and a little amount of alcohol, which was discarded. The organic layer was then dried by extracting it with sodium bicarbonate; this is an extra step for drying the alkyl halide. The resulting organic layer contained the crude n-butyl bromide, and the drying procedure was completed by adding anhydrous calcium chloride until the solution turned clear. The drying agent was used to absorb any excess water and thus, resulted in a clear solution of n-butyl…

    • 768 Words
    • 4 Pages
    Good Essays
  • Satisfactory Essays

    5) Using the cooled solution of benzoic acid crystals, filter out the benzoic acid from the table salt using funnels.…

    • 522 Words
    • 3 Pages
    Satisfactory Essays
  • Good Essays

    water on the beaker with sodium carbonate. Use a stirring rod to stir it and then we you…

    • 612 Words
    • 3 Pages
    Good Essays
  • Good Essays

    1. Recrystallization- Purify a crystal. Find a solvent that dissolves the crystals when boiling, and recrystallizes when cool. (The same solvent should not dissolve it when cold). A crystal is extremely organized,…

    • 922 Words
    • 4 Pages
    Good Essays
  • Better Essays

    orgo lab

    • 993 Words
    • 4 Pages

    After recrystallization of the benzoic acid, the starting and ending masses as well as the melting point ranges were determined. This experiment was conducted twice, following the same steps and guidelines.…

    • 993 Words
    • 4 Pages
    Better Essays
  • Satisfactory Essays

    Experiment 1 Procedures

    • 537 Words
    • 3 Pages

    Procedure: To a 125 mL Erlenmeyer flask containing a mixture of 95% ethanol (6 mL) and acetic acid (5 mL), dissolve acetanilide (7.4 mmol) and sodium bromide (1.8 g). Place the reaction flask in an ice bath (at least 5oC) for 5 minutes (keep this reaction in the hood). Add sodium hypochlorite (8.3 mmol) by addition of household bleach; leave the reaction flask in the ice bath 5 min. After removing the flask from the ice bath and placing a watch glass over the opening, allow the reaction mixture to come to room temperature over 15 minutes. Place the reaction flask into the ice bath and quench the unreacted bromine by addition of both 5 mL of sodium thiosulfate solution (1 g/5 mL) and 5 mL sodium hydroxide solution(1 g/5 mL ); collect the product by suction filtration. Recrystalllize the brominated product from a minimum amount of solvent. You will need to select a solvent from water, 50% ethanol or 95% ethanol. To identify the best solvent, use what you have learned in Organic I Chemistry Lab, hint: think about what properties makes a good recrystallization solvent. Test your recrystallization solvent in test tubes using the tip of a spatula of your compound. Remember to use a water bath to heat organic solvents. NEVER heat organic solvents directly on a hot plate-always use a hot water bath! Dry the product and obtain melting point range (one fast and one slow) and an IR spectrum. Be sure to record observations in your laboratory notebook.…

    • 537 Words
    • 3 Pages
    Satisfactory Essays
  • Good Essays

    6.05 Chemistry

    • 367 Words
    • 2 Pages

    6. Then you need to change the temperature of the water and add one Alka-Seltzer and see how long it takes for it to dissolve.…

    • 367 Words
    • 2 Pages
    Good Essays
  • Better Essays

    Nucleophilic Hydride Lab

    • 937 Words
    • 4 Pages

    The purpose of this laboratory is to convert benzophenone to diphenylmethanol. This was done by using sodium borohydride to reduce benzophenone. The product was then crystalized from hexanes then using the melting point and IR testing it was possible to characterize it. The melting point range was……

    • 937 Words
    • 4 Pages
    Better Essays
  • Good Essays

    The product was placed in a beaker, and enough aqueous methylated spirit (IMS) was added whilst the mixture was heated to dissolve the product. The mixture was then left to cool and was placed in ice to aid crystallization. The product was vacuum filtrated after a few minutes of standing in ice and the crystals were collected and dried in a vacuum oven at 40 degrees celsius. The mass of the crystals was calculated and the melting point was determined.…

    • 652 Words
    • 3 Pages
    Good Essays
  • Good Essays

    ap english

    • 544 Words
    • 3 Pages

    5. I filled two cups up, one with a saltwater mixture and one with rubbing alcohol to 1/4 inch.…

    • 544 Words
    • 3 Pages
    Good Essays
  • Powerful Essays

    Naphthalene Chromatography

    • 1479 Words
    • 6 Pages

    Finding the melting point of an organic substance is a practical and efficient way for scientists to identify an unknown substance or determine a known substance's level of purity. When organic substances are mixed together in varying degrees they take on a melting characteristic that is lower and broader than in its pure form. This property was manipulated in the lab to observe the various melting points of Naphthalene and Biphenyl when the percentage of composition was altered. A eutectic point of 45 °C at 52% Naphthalene was determined from the class data. An unknown crystalline substance was identified to be Benzophenone by mixing and finding its melting point with known substances.…

    • 1479 Words
    • 6 Pages
    Powerful Essays
  • Better Essays

    Chem Lab

    • 858 Words
    • 4 Pages

    There are millions of different organic compounds. Most of them are found in mixtures and in order to achieve a pure form they need to be separated, isolated, and purified. However, there are endless numbers of possible mixtures, which make it impossible to have a pre-designed procedure for every mixture. So chemists often have to make their own procedures. The purpose of this experiment was to prepare the student to the real world by them designing their own procedure which will help them understand the techniques of separation and purification better. The goal was to extract two of the components of the mixture that consisted of 50% benzoic acid, 40% benzoin, and 10% dibromobenzene. The benzoic acid was extracted by the use of base and extraction technique. Then a crystallization was performed in order to separate benzoin by the use of hexane a solvent, leaving the dibromobenzne in the mother liquor. The percent recovery for benzoic acid was 91.8% and 80.3% for the benzoin. The MP for benzoic acid was 119-122°C (1) and 135-136°C (2)for the benzoin. The high percent recovery and closeness of measured MP to the literature value indicate that the designed procedure was successful.…

    • 858 Words
    • 4 Pages
    Better Essays
  • Satisfactory Essays

    To study the affect of pH on a food preservative. Sodium benzoate changed into benzoic acid once the 3 M of HCl was added making it a pH of 2, making the solution acidic. The hydronium ion concentration was high enough that it gave a yield of benzoic acid, which, is very insoluble in water and it formed a precipitate in the solution. The end percent yield was 132.352%, this was due to a few flaws in the experiment. During the filtration process of the experiment the funnel was not working properly and not all the…

    • 690 Words
    • 3 Pages
    Satisfactory Essays

Related Topics