Polarity index Sohim M.Pharma 1st year Presented to Jayanta Kumar Maji 2014-2015 Presented to Jayanta Kumar Maji At Gujarat Ayurved University On April-2015

Content INTRODUCTION DIELECTRIC CONSTANT POLARITY SOLVENT POLARITY CHART SOLVENT POLARITY INDEX TABLE APPLICATION OF POLARITY INDEX

INTRODUCTION Extracted compound is based on the type of solvents used. Polar solvent isolates polar compound and non-polar solvent extracts non-polar compound. Different solvents yield different extracts and extract composition.

DIELECTRIC CONSTANT Dielectric constant: a measure of a solvent’s ability to insulate opposite charges from one another The most common measure of solvent polarity is dielectric constant

POLARITY Solvents are classified as polar and nonpolar. The greater the value of the dielectric constant of a Solvent , the smaller the interaction between ions of opposite charge dissolved in that solvent. Polar Solvent: Dielectric constant > 15 Non-Polar Solvent: Dielectric constant < 15

Solvent-Solvent Interactions: Liquids having similar dielectric constants (e.g., H2O and acetonitrile) are likely to be miscible (soluble in all proportions) while liquids having very different K values (e.g., H2O and hexane) are normally immiscible (insoluble in each other). The general rule is ‘like dissolves like’.

SOLVENT’S CHOICE A property of a good solvent in plant extraction: Low toxicity Ease of evaporation at low heat Promotion of rapid physiologic absorption of the extract Preservative action Inability to cause the extract to complex or dissociate

SOLVENT POLARITY CHART

Solvent Polarity index table: Dielectric Constant(K) Refractive index @ 20C UV(nm) Cutoff @ 1AU B.P© M.P© Viscosity(c poise) Solubility in Water (%w/w) Density (g/ml) Acetic acid 6.2 1.372 230 118 -17 1.26 100 1.04 Acetone 5.1 1.359 330 56 0.32 Acetonitrile 5.8 3.6 1.344 190 82 -45 0.37 0.79 Ammonia 23 0.69 Benzene 2.7 2.3 1.501 280 80 5 0.65 0.18 0.88 n-Butanol 4 1.394 254 125 0.73 0.43 Butyl acetate 3.9 1.399 215 2.98 7.81

Carbon tetrachloride 1.6 2 1.466 263 77 -23 0.97 0.08 1.59 Chloroform 4.1 4.8 1.446 245 61 -64 0.57 0.815 1.48 Cyclohexane 0.2 1.426 200 81 1 0.01 1,2-Dichloroethane 3.5 1.444 225 84 0.79 0.81 Dichloromethane 3.1 1.424 235 41 0.44 Dimethylether 21 56 -95 Dimethylformamide 6.4 1.431 268 155 0.92 100 Dimethylsulfoxide 7.2 47 1.478 189 18 1.1 Dioxane 1.422 215 101 1.54

Ethanol 5.2 24 1.36 210 78 -117 1.2 100 0.79 Ethyl acetate 4.4 1.372 260 77 0.45 8.7 Di-Ethyl Ether 2.8 1.353 220 35 0.32 6.89 Formamide 110 193 3 1.13 Heptane 1.387 200 98 0.39 0.0003 Hexane 2 1.375 69 -95 0.33 0.001 0.66 Hydrogen Flouride 84 20 -83 1.002 Methanol 5.1 33 1.329 205 65 -94 0.6 Methyl-t-Butyl ether 2.5 1.369 55 0.27 4.8 Methyl Ethyl Ketone 4.7 1.379 329 80 Pentane 1.358 36 0.23 0.004 n-propanol 4 1.384 97 2.27 Iso-propanol 3.9 1.377 82 2.3 Di-Isopropyl ether 2.2 1.368 68 0.37

Sulfuric acid 101 270 10 1.83 Tetrahydrofuran 4 7.6 1.407 215 65 -65 0.55 100 0.89 Toluene 2.4 1.496 285 111 0.59 0.051 Tichloroethylene 1 1.477 273 87 0.57 0.11 Water 9 81 1.333 200 0.998 Xylene 2.5 1.5 290 139 0.61 0.018

Application of polarity index: Solvent system designing: Snyder Prism Algorithm

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