Difference Between Solubility Dependent Extraction And Recrystallization

Improved Essays
The motivation behind this experiment was to gain insight behind the theory and practice of two laboratory techniques: solubility-dependent extraction, and recrystallization, in an effort to isolate and identify three compounds originally dissolved in a mixture. Extraction is used to isolate a specific compound. Recrystallization involves taking a crude compound and removing unwanted impurities so that a more accurate melting point can be taken, leading to a more precise identification of a compound. The overarching goal was to isolate and identify three different unknowns in a given sample using these techniques. There are two types of extractions; solid-liquid extractions involve extracting a soluble compound from an insoluble (solid) material …show more content…
Upon vigorous mixture of original and extraction solvent, an optimization of physical contact (surface area) between the extraction solvent and desired compound drives the compound to migrate into the extraction solvent because of its more favorable solubility. There are four rules that dictate whether a chosen solvent can efficiently be used to extract a specific compound. For one, the original solvent and extraction solvent must be immiscible. If these solvents do mix, one will only make a more complex mixture that will be hard to separate. Secondly, the extraction solvent must not irreversibly react with the desired compound, this would decrease yield of product and result in an inefficient extraction. Thirdly, the extraction phase should selectively remove the desired compound; non-selectivity of the solvent could result in extracting multiple compounds. Lastly, the extraction …show more content…
The process of extraction also heavily weighs on the fact that compounds are more favorably soluble in a certain solvent based on solubility characteristics of the desired compound. There are four factors that determine the solubility characteristic of a compound: pH, temperature of the solvent, pressure of the system, and ionic character of solute. Ionic character and pH were manipulated to increase solubility favorability of the compound in extraction solvent. In essence, pH is the easiest factor to manipulate because it merely involves using an aqueous acid or base as an extraction solvent that simultaneously abides by the four solvent requirements of extraction. In regard to recrystallization, an impure compound is allowed to dissolved into a solvent and then allowed to reform as a pure solid because of the fact that the impurities of the crude sample are either fully soluble or insoluble in the solvent chosen. Three criteria must be met for this phenomenon to occur: the compound to be purified must be soluble in a relatively hot solvent, the compound to be purified must be

Related Documents

  • Superior Essays

    Starting out, there was a mixture of an unknown acid, base, and neutral component. Just like the process outlined in the introduction, a solvent would be added to the solution containing the acid, base, and neutral unknown mixture. This solvent must have specific characteristics regarding solubility such that it dissolves the substance desired to be extracted while not dissolving or dissolving in only small portions the other substance not wanted purified out. It should also be easy to separate from the compound left in it after purification of the other so that complete purification can take take place4. This is why diethyl ether was used because it is a hydrocarbon, meaning it is mostly insoluble in water and satisfies the requirements discussed.…

    • 1718 Words
    • 7 Pages
    Superior Essays
  • Great Essays

    In the Acid-Catalyzed Hydration of norbornene, water and sulfuric acid were added to the C=C double bond to form norborneol. Sulfuric acid acted as a catalyst, where it was not consumed in the reaction and helped to propel the reaction forward, as it was vital in forming hydronium ion and breaking the double bond. Both the products endo-norborneol and exo-norborneol were synthesized; however regioselectivity and stereoselectivity played a role as to which product was more preferred and whether the equatorial or axial orientation of the hydroxy group was favored.The setup of the Cold-Finger, and the ability of norborneol to sublime readily allowed for the purification of the crude product to obtain the diastereomeric products exo- and endo-norborneol.…

    • 1629 Words
    • 7 Pages
    Great Essays
  • Great Essays

    An ideal recrystallization solvent should have these properties: - The compound is soluble in hot temperature and insoluble in cold temperature. The difference in at hot and cold temperature is very important to the process. Because when the solvent is insoluble in hot temperature, it will not dissolve result in cannot be recrystallized. - There are two phases to identify the unwanted impurities: dissolved form present in solvent at normal temperature or undissolved form in higher temperature. Therefore, the impurities will be taken out using the hot filtration when dissolving the impure solids.…

    • 1460 Words
    • 6 Pages
    Great Essays
  • Great Essays

    Solubility

    • 1984 Words
    • 8 Pages

    Solubility is not to be confused with the ability to dissolve or liquefy a substance, since this process may occur not only because of dissolution but also because of a chemical reaction. Low aqueous solubility is the major problem encountered with formulation development of new chemical entities as well as for the generic development . The purpose of this review article is to describe the techniques of solubilizaton for the attainment of effective absorption and improved bioavailability. Keywords: Solubility, solubility enhancement, co-solvent, pH, emulsions INTRODUCTION A number of methodologies can be adapted to improve solubilization of poor water soluble drug and further to improve its bioavailability. The techniques generally employed for solubilization of drug includes micronization, chemical modification, pH adjustment, solid dispersion, complexation, co‐solvency,…

    • 1984 Words
    • 8 Pages
    Great Essays
  • Improved Essays

    Aims of Experiment 1. To extract benzoic acid from the toluene-benzoic acid mixture, using oxidation-reduction reaction (chemical properties) and difference of solubility (physical properties) –Expt. 1 2. To learn how to recrystallize the solid organic compounds well for getting more purified compounds –Expt. 2 3.…

    • 721 Words
    • 3 Pages
    Improved Essays
  • Improved Essays

    Distillation Lab Report

    • 1011 Words
    • 5 Pages

    Once the fractional distillation setup is complete, the stirbar in the Erlenmeyer flask containing the binary solution is turned on to ensure homogeneous boiling. As the solution starts to boil, vapor containing the more volatile component travels upward through the column until the temperature gradient becomes too cool and it condensates on the side of the distillation column. The verticality of the column provides a surface area for the vapors to condense and flow back down the column until the temperature becomes hot enough for it to vaporize again. This process of re-condensation and re-evaporation continues until the vapor becomes purely the more volatile compound. Once at the stillhead, the pure vapor meets a water-cooled condenser that cools the vapor causing it to condensate and flow into a Falcon tube receiver.…

    • 1011 Words
    • 5 Pages
    Improved Essays
  • Improved Essays

    Lab Report Cation Essay

    • 875 Words
    • 4 Pages

    CH 204- Introduction to Chemical Practices Experiment 1- Qualitative Analysis of Cations Sharon Alexander Kathrynn Labat TA: Yu-Chun Lin September 25, 2017 Results & Discussion This experiment was composed of three parts. In the first part, qualitative methods were used to identify the unknown cation in an aqueous solution. The cation was to be either lead or silver. If silver was present, extra steps were needed to be taken in order to confirm its presence in the solution. In the second part of the experiment, qualitative methods were used again to determine the identity of the other cation in the original aqueous solution of the first part.…

    • 875 Words
    • 4 Pages
    Improved Essays
  • Improved Essays

    It is also important to have an aqueous solvent that is free of cross-linking ions to enable dissolution [3]. 1.1.1.4 Viscosity The viscosity of alginate is influenced by many parameters such as the concentration and the temperature of the used alginate, whereby the concentration has a positive influence and the temperature has a negative relationship. The viscosity of alginate solutions increases as well by decreasing pH, as carboxylate groups in the alginate backbone become protonated, form hydrogen bonds and reach a maximum around pH = 3–3.5 [3]. Another factor that affects the viscosity ist the length of the alginate molecule, or the number of the monomer units in the chains (MW), the longer chains have higher…

    • 734 Words
    • 3 Pages
    Improved Essays
  • Improved Essays

    Recrystallization Essay

    • 743 Words
    • 3 Pages

    The main purpose of this experiment is to purify an impure solid by the technique of recrystallization. This technique involves several steps, selecting an ideal solvent, dissolving the compound in a minimum amount of boiling hot solvent, filtering insoluble impurities while the solution is hot; crystallizing the purified compound, and isolate the pure compound by vacuum filtration . The unknown used in the experiment was #4, which were white crystals. In order to determine the ideal solvent we prepared two test tubes. Test tube #1 containing 0.106g of unknown and 3mL of water, it was well mixed.…

    • 743 Words
    • 3 Pages
    Improved Essays
  • Improved Essays

    Acid base titrations: A titration is the addition of a measured volume of one solution, from a burette, to an unknown volume/concentration of another solution until the reaction between then is complete. An acid base titration is carried out to determine an unknown concentration by using a solution of known concentration. An indicator is used to show a dramatic and rapid colour change, at the end point of the titration. Preparing a standard solution: The substance used for the standard solution must have a high degree of purity, preferably solid, because this is easier to measure (using a scale) and the substance can’t absorb water or release water. Oxalic acid and anhydrous sodium carbonate are used to make the standard solutions.…

    • 803 Words
    • 4 Pages
    Improved Essays