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Solvent drying


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Here i am defining complete idea of solvents and its detail with good example!

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Solvent drying

  1. 1. Solvents & Solvent Drying
  2. 2. What is a Solution ? Solute Solvent Solution Sugar Water Solution Example:
  3. 3. SOLUTION
  4. 4. What is a Solvent? • The liquid in which a solute is dissolved to form a solution. • The term “solvents” refers to liquid organic chemicals used to dissolve solid materials. • A solvent is a substance that dissolves a solute, resulting in a solution. • A solvent is usually a liquid but can also be a solid or a gas. • The maximum quantity of solute that can dissolve in a specific volume of solvent varies with temperature.
  5. 5. Liquid-liquid separation is a useful method to separate components (compounds) of a mixture
  6. 6. Let's see an example. Suppose that you have a mixture of sugar in vegetable oil (it tastes sweet!) and you want to separate the sugar from the oil. You observe that the sugar particles are too tiny to filter and you suspect that the sugar is partially dissolved in the vegetable oil. What will you do?
  7. 7. How about shaking the mixture with water Will it separate the sugar from the oil? Sugar is much more soluble in water than in vegetable oil, and, as you know, water is immiscible (=not soluble) with oil. Did you see the result? The water phase is the bottom layer and the oil phase is the top layer, because water is denser than oil. *You have not shaken the mixture yet, so sugar is still in the oil phase.
  8. 8. By shaking the layers (phases) well, you increase the contact area between the two phases. The sugar will move to the phase in which it is most soluble: the water layer
  9. 9. Now the water phase tastes sweet,
because the sugar is moved to the water phase upon shaking.**You extracted sugar from the oil with water.**In this example,
 water was the extraction solvent ;the original oil-sugar mixture was the solution to be extracted; and sugar was the compound extracted from one phase to another. Separating the two layers accomplishes the separation of the sugar from the vegetable oil
  10. 10. Why only water ?
  11. 11. Polar & Non-Polar Solvents Polar solvents have large dipole moments (aka “partial charges”); they contain bonds between atoms with very different electro negativities, such as oxygen and hydrogen. Non polar solvents contain bonds between atoms with similar electro negativities, such as carbon and hydrogen (think hydrocarbons, such as gasoline). Bonds between atoms with similar electro negativities will lack partial charges; it’s this absence of charge which makes these molecules “non-polar”.
  12. 12.  Molecules with a hydroxyl group (-O-H) are generally soluble in water.  Other substances, like fats, are non-polar . They will not dissolve in water.  These substances are neutral and there is no excess charge at one end of the molecule. Examples are, benzene (C6H6), and carbon tetrachloride (CCl4). Benzene will dissolve in carbon tetra-chloride.  Molecules that are hydrocarbons (mostly C and H) will dissolve in other hydrocarbons. A basic rule is: Like dissolves in Like .  This means that,
 in general,
 polar substances will dissolve in other polar substances,
 and that non-polar substances will dissolve in other non-polar substances.  Polar substances will not dissolve non-polar substances.
  13. 13. A solvent is a liquid that serves as the medium for a reaction. It can serve two major purposes:  (Non-participatory) to dissolve the reactants. Remember “like dissolves like” ? Polar solvents are best for dissolving polar reactants (such as ions); nonpolar solvents are best for dissolving nonpolar reactants (such as hydrocarbons).  Participatory: as a source of acid (proton), base (removing protons), or as a nucleophile (donating a lone pair of electrons).
  14. 14. Remember water & oil example ? • Think of how oil and water don't mix. Water is polar and oil is nonpolar. • A polar molecule has poles, basically some areas are charged negatively and some are charged positively. • A soap is a salt of a fatty acid, it has a polar end that "likes" water and a long non-polar chain that "likes" oil.
  15. 15. Uses of Solvents As a Solvent • Dissolution • Extraction • Degreasing • Inks, dyes, paints, coatings • Dilution, dispersal • Dry cleaning As Something Else • Fuels • Feedstocks • Drugs of abuse • Beverages • Antifreeze • Explosives • Pollutants
  16. 16. Removing water from Solvents There are various ways of removing water and other impurities from a solution. This can become a major task once the used reagents are also sensitive towards water.  The drying agents commonly used in the organic laboratories are the anhydrous forms of calcium chloride (CaCl2), sodium sulfate (Na2SO4) Calcium sulfate (CaSO4 and magnesium sulfate (MgSO4).
  17. 17. Pore sizes in adsorbents may be distributed throughout the solid. Pore sizes are classified generally into 3 ranges:  macropores have "diamaters" in excess of 50-nm,  mesopores (also known as transitional pores) have "diameters" in the range 2 - 50-nm, and  micropores have "diameters" which are smaller than 2-nm.
  18. 18. Types
  19. 19. 3A Molecular Sieves : 3A (pore size 3 ): Adsorbs NH 3, H2O, (not C2H6), good for drying polar liquids 4A Molecular Sieves : 4A (pore size 4 ): Adsorbs H 2O, CO2, SO2, H2S, C2H4, C2H6, C3H6, ethanol. Will not adsorb C3H8 and higher hydrocarbons. Good for drying nonpolar liquids and gases. 5A Molecular Sieves : 5A (pore size 5 ): Adsorbs normal (linear) hydrocarbons to n-C4H10, alcohols to C4H9OH, mercaptans to C4H9SH. Will not adsorb isocompounds or ring structures with more than four carbon atoms. 10X Molecular Sieves : 10x (pore size 8 ): Adsorbs branched hydrocarbons and aromatics. Used for drying gases. 13X Molecular Sieves : 13x (pore size 10 ): Adsorbs di-n-butylamine (not tri-n-butylamine).
  20. 20. Applications Why is acetone, instead of water, used to extract chlorophyll and other green leaf pigments? The pigments and the rest of the leave stuff will just stick together in water. Acetone is an organic solvent that can separate the aqueous impurities from the pigments in leaves. Drying of Acetone. Acetone has been dried with a wide spectrum of desiccants. Thus, alumina, calcium chloride, phosphorus pentoxide, and 4A molecular sieves, as well as calcium and (anhydrous) cupric sulfate, have all been used.
  21. 21. Applications  Ethanol is used in perfumes & after shaves.  Acetone is used in Chlorophyll Extraction because it is an organic solvent.  It can split the aqueous impurity from the pigment in leaves unlike when water is used.  Isopropyl Alcohol used as a solvent in bulk drug API mfg.
  22. 22. Solvents in Rubber & Polymers Making better products... Solvents are used in many different processes within the polymer manufacturing industry, e.g. in the production of rubber or tyres and in polyolefin's manufacturing.  Dearomatised aliphatic hydrocarbon solvents are applied in the production of tyres to ‘glue’ together the many different pieces and layers of rubber, ensuring they are safe and durable. Methyl isobutyl ketone (MIBK) is used as a raw material in the manufacture of rubber antiozonants.
  23. 23.  In the shoe industry, a major breakthrough occurred in 1928 when polychloroprene was first introduced.  The first, simple formulation is still manufactured and is used worldwide because the glue can be easily prepared by simply making a solution of the polymer.  This gives a product with good adhesion to various substrates.  Many new products are available today as potential replacements. Hot melt adhesives can be used in some applications but they still require solvents for cleaning, degreasing, and swelling.  Water-based adhesives are the most likely replacement product.
  24. 24. MOLECULAR SIEVES FOR SOLVENT DRYING:  This market includes the drying of solvents used for cleaning and/or purification of a material. This type of drying is found in chemical plants, refineries, manufacturing plants, etc. where a material is rinsed by a hydrocarbon stream, then recycled, dried, and returned to cleanse the material.  For example, an acetone liquid stream is used to wash a thread used for making tea bags REPRESENTATIVE TYPES OF SOLVENTS BEING RECOVERED Acetates Acetone Benzene (MIBK) Chloroform Cyclohexanone Ethanol Ether Freons Gasoline Heptane Hexane Isopropyl Alcohol (IPA) Methanol Methyl Ethyl Ketone (MEK) Methyl Isobutyl Ketone Methylene Chloride Mineral Spirits Pentane Perchloroethylene Propanols Tetrahydrofuran (THF) Toluene Trichloroethane Trichloroethylene Xylene
  25. 25. Solvent drying guide TO DRY USE ONE OF THE FOLLOWING DRYING AGENTS Alcohols Anhydrous forms of potassium carbonate; anhydrous magnesium or calcium sulphate; quicklime. Alkyl halides Aryl halides Anhydrous calcium chloride; anhydrous forms of sodium sulphate, magnesium sulphate, or calcium sulphate; sodium pentoxide. Saturated and Anhydrous calcium chloride or sulphate; metallic sodium; phosphorus Aromatic hydrocarbons pentoxide. Aldehydes Ketones Anhydrous sodium sulphate; anhydrous magnesium or calcium sulphate. Anhydrous sodium sulphate; anhydrous magnesium or calcium sulphate; anhydrous potassium carbonate. Organic bases (amines) Solid potassium or sodium hydroxide; quicklime; barium oxide. Organic acids Anhydrous sodium sulphate; anhydrous magnesium or calcium sulphate.
  26. 26. Solvent drying using Molecular Sieves Solvent Acetone Acetonitrile Benzene CTC Chloroform Cyclohexane Dichloromethane Diethyl ether DMF DMSO 1,4 Dioxane Ethanol Ethyl acetate Hexane Methanol 2 propanol Pyridine THF Tolune Xylene BP 56 82 80 77 62 81 40 34 153 189 101 79 77 69 65 82 116 66 111 137 Molecular Sieve 3A 3A / 4A SILICA 4A / 5A 4A 4A 4A 4A / 3A 4A 4A 3A 4A 3A 4A 4A 4A 3A 4A 4A / 3A 4A / 5A 4A