Dimethyl Phthalate
Formula
C10H10O4
Preparation
Dimethyl phthalate can be prepared in two common ways:
- Oxidation of o-xylene followed by esterification with methyl alcohol.
- Oxidation of xylene using potassium permanganate to produce phthalic acid, which then reacts with methyl alcohol to form dimethyl phthalate.
Test for Purity
Limit Test for Phthalic Acid:
- Using pH testing to check for acidity.
- Effervescence when treated with sodium carbonate indicates the presence of acids.
Assay
Weigh about 2 g of dimethyl phthalate into a 250 ml flask fitted with a reflux condenser. Add 50 ml of 0.5 N NaOH and 10 ml water, then reflux for 1 hour.
Wash down the sides with 2.5 ml water, cool, add 0.2 ml thymol blue, and titrate the remaining alkali with 0.5 N HCl until a yellow colour appears.
Uses
- Used as an ectoparasiticide to kill organisms living on skin or body surfaces.
- Used in solid rocket propellants.
- Commonly used in the production of plastics.
- Serves as an insect repellent.
Detailed Notes:
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PATH: PHARMD/PHARMD NOTES/ PHARMD FIRST YEAR NOTES/ ORGANIC CHEMISTRY/ PHARMACEUTICAL ORGANIC CHEMISTRY/ DIMETHYL PTHALATE.