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Question: question 3amp4...

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question 3&4EXPERIMENT #1-SULFONATION OF p-XYLENE CH CH H.so CH CH Procedure Set up a water bath by heating water to boiling in crystallizing dish on a combination stirrer-hot plate. Into a 10 mL round-bottomed flask, place a magnetic stirrer. Add p- xylene (1.2 mL, 1.04 g) followed by 2 mL of concentrated sulfuric acid dropwise (by means of a Pasteur pipette), swirling the contents of the round-bottomed flask during this addition. Heat the mixture in the water bath, with continuous stirring, for 20-25 minutes The reaction is complete when the xylene layer has disappeared and the solution has a light straw colour. While heating, place a drop of p-xylene on a TLC plate and label it SM. Cool slightly and pour into a 50mL beaker. Add cold water (1.0 mL) (CAUTION WATER INTO ACID!) and cool in ice. A solid white mass forms. Vacuum filter using a Buchner funnel containing a single glass fiber filter paper. If necessary, use a glass stopper to press down the precipitate to remove any remaining acid. Recrystallize from a minimum amount of boiling water (a few drops will suffice). Filter and press between filter paper to remove excess moisture. Dissolve a small portion of this in some acetone and spot it on the TLC plate as well, labeling it R. Develop the TLC normally and take note of the solvent system used. Store the remaining product in a dessicator until the following week. This will help remove excess water from the product. Determine the m.p. and yield of the recrystallized material next week while doing experiment #2.
QUESTIONS: 1. Is the H2S04 present in excess? If so, how much? 2. Is this a reversible electrophilic substitution? Why? 3. How many p-xylene monosulfonic acids are possible? 4. How many p-xylene disulfonic acids are possible? Give structures of all possible somerS.

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