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Preparation of Sulfaniliamide: Chlorosulfonation Step

1) What happens when chlorosulfonic acid comes in contact with water?

2) How will you safely destroy any residual of chlorosulfonic acid remaining on your glassware?

3) Why do experimenter says "The reaction is most easily controlled when acetanilide is in the form of a hard cake, the dried solid is melted, as the melt cools, the flask is swirled to distribute the material as it solidifies over the lower walls of the flask."?

4) Draw the 3-D structure of the product for the "chlorosulfonation of acetanilide in the preparation of sulfanilamide"?

5) What is a "filter cake"?

6) Draw the structure of the compound referred to as the "filter cake" in the first sentence of below paragraph.
"Cool the flask containing the acetanilide thoroughly in an ice-water bath, and for 5.0 g of acetanilide measure 12.5 mL of chlorosulfonic acid in a graduated cylinder (supplied with the reagent and kept away from water). Add the reagent in 1-2 mL portions with a capillary dropping tube and connect the flask to the gas trap. The flask is now removed from the ice bath and swirled until a portion of the solid has dissolved and the evolution of hydrogen chloride is proceeding rapidly. Occasional cooling in ice may be required to prevent too brisk a reaction. The reaction subsides in 5-10 min, with only a few lumps of acetanilide remaining undissolved. When this point has been reached, heat the mixture on a steam or sand bath for 10 min to complete the reaction, cool the flask under the tap, and deliver the oil by drops with a capillary dropper while stirring it into 75 mL of ice water contained in a beaker cooled in an ice bath (in the hood). Use extreme caution when adding the oil to the ice water and when rinsing out any containers that have held chlorosulfonic acid. Rinse the flask with cold water and stir the precipitated p-acetaminobenzenesulfonyl chloride for a few minutes until an even suspension of granular white solid is obtained. Collect and wash the solid on a Buchner funnel. After pressing and draining the filter cake, transfer the solid to the rinsed reaction flask, add (for each 5 g of acetanilide) 15 mL of concentrated aqueous ammonia solution and 15 mL of water, and heat the mixture over a flame or sand ....."

7) Why does Chlorosulfonic acid react violently with water?

8) Last week aniline was protected with an acetyl group in preparation for this week's reaction. In what ways would the preparation of p-acetamidobenzenesulfonylchloride have failed if aniline were used for the chlorosulfonation step instead of acetanilide? Please elaborate your answer.

9) Concentrated ammonia is actually 72% water. Although concentrated ammonia is called "ammonium hydroxide" the pKb is about 5 and the following equilibrium lies well to the reactants side:
NH3(aq) + H2O  NH+4 (aq) + OH- (aq).
Explain why even though the concentration of H2O molecules is more than 1000 times greater than the concentration of NH3 molecules p-acetamidobenzenesulfonamide acid.

10) Write a balanced equation for the reaction of 4-acetamidobenzenesulfonyl chloride with ammonia. Use this equation to explain why two moles of ammonia is required for each mole of 4-acetamidobenzenesulfonyl chloride in this reaction.

11) Show a mechanism for 4-acetamidobenzenesulfonyl chloride with ammonia. Draw the 3-D configuration of the product and name the product.


Solution Summary

Questions reagarding Preparation of Sulfaniliamide: Chlorosulfonation Step are answered in detail.