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How fluorescein is prepared from resorcinol?
Fluorescein is an organic compound that has wide use as a synthetic coloring agent. It is prepared by heating phthalic anhydride and resorcinol over a zinc catalyst, and it crystallizes as a deep red powder.
What happens when phthalic anhydride is heated with resorcinol in presence of Lewis acid?
Phthalic acid loses water on heating and acts as a dehydrating agent. The reaction of phthalic anhydride with resorcinol results in the formation of organic dye.
Why the synthesis of fluorescein is relevant?
It increases the electrophilicity of pthalic anhydride in the first step, and facilitates the elimination of the hydroxyl groups. In order to get the form of the molecule shown as the product of the reaction, the pH needs to be increased in order to open the lactone ring.
What is the theoretical yield of fluorescein in your synthesis?
Fluorescein theoretical yield was calculated to be . 22g. The actual yield synthesized of fluorescein was calculated to be 36% with . 08g collected.
How do you synthesis fluorescein?
Synthesis. Fluorescein was first synthesized by Adolf von Baeyer in 1871. It can be prepared from phthalic anhydride and resorcinol in the presence of zinc chloride via the Friedel-Crafts reaction. A second method to prepare fluorescein uses methanesulfonic acid as a Brønsted acid catalyst.
How do you make phthalic anhydride from phthalic acid?
Phthalic anhydride is presently obtained by catalytic oxidation of ortho–xylene or naphthalene. When separating the phthalic anhydride from production by products such as o–xylene in water, or maleic anhydride, a series of “switch condensers” is required. Phthalic anhydride can also be prepared from phthalic acid.
What is the structure of fluorescein?
C20H12O5
Fluorescein/Formula
What is resorcinol reagent?
Resorcinol is an analytical reagent for the qualitative determination of ketoses (Seliwanoff’s test). Resorcinol is the starting material for resorcinarene molecules and the initiating explosive lead styphnate. Resorcinol reacts with formaldehyde to form a thermoset resin which can form the basis of an aerogel.
How to make fluorescein with phthalic anhydride?
Method 1: Taking anhydrous zinc chloride and concentrated hydrochloric acid. Grind 15 g of phthalic anhydride and 22 g. of resorcinol together and transfer the mixture to a conical flask. Heat the flask on an oil bath to 180° (internal temperature).
What is the mechanism of action of fluorescein?
Fluorescein is a Diagnostic Dye. The mechanism of action of fluorescein is as a Dye. Fluorescein is an organic compound that has wide use as a synthetic coloring agent. It is prepared by heating phthalic anhydride and resorcinol over a zinc catalyst, and it crystallizes as a deep red powder.
How is fluorescein prepared as a synthetic coloring agent?
Fluorescein is an organic compound that has wide use as a synthetic coloring agent. It is prepared by heating phthalic anhydride and resorcinol over a zinc catalyst, and it crystallizes as a deep red powder.
How to make resorcinol with phthalic anhydride?
Grind 15 g of phthalic anhydride and 22 g. of resorcinol together and transfer the mixture to a conical flask. Heat the flask on an oil bath to 180° (internal temperature).