[adam_goalietender]

I recently did a lab in class involving the formation of asprin from salicylic acid (2-hydroxybenzanoic acid) and acetly acid (ethanoic acid). These two acids condense to form an ester that is asprin (2-(acetlyoxy)benzanoic acid.
In this lab we are asked to describe any observations and find the precenatage yield of asprin.

This is the procedure. taken from Kessel, Hans van  etal. "Chemistry 12"(2003). Nelson Thompson, Tornto Canada. P. 91 modified a bit by my chem teacher.

1.   Prepare a hot-water bath by heating 300-mL of water in a 300-mL beaker on a hot plate until boiling
2.   Obtain approx. 4 g of salicylic acid and determine its mass to the nearest 0.01 g. Transfer the sample to a 50-mL Erlenmeyer flask.
3.   In a fume hood, add to the Erlenmeyer flask 8.0 mL of acetic acid, and stir with a glass stirring rod until all the solid has dissolved
4.   Remain in the fume hood and, using a plastic dropper, carefully add 4 drops of concentrated H2SO4(aq). Stir the mixture
5.   Remove the conical flask from the hot water bath and add to it about 20g of crushed ice and about 20mL of ice water. Place the flask in the ice bath and stir for about 10 min.
6.   Determine the mass of a piece of filter paper to the nearest 0.01g. and set up the filtration apparatus. Carefully filter the contents of the Erlenmeyer flask and wash the crystals with 10mL of ice water.
7.   Allow the filter paper and crystals to dry completely. Determine the mass of the dry filter paper and crystals.

I have 2 questions.

1. Why does salicylic acid look like a it has a crystal like structure? I know that ionic compounds form a crystal structure due to their strong intermolecular forces. I also know that water will form a cystal like structe that looks different from the structure that ionic compouns make. So where does salicylic acid fit into all this? Do its -OH groups create a strong enough interaction that they will create a cyrstal like structure when not dissolved in water. Do all acids act like this? Does in have to do with the benzene ring structure of the acid? Any help or reference pages to this topic would be much appreciated. I have already tried searching on the web about this and i couldn't find much.

2. Is asprin soluble? I may have heard my chemistry teacher wrong but i heard him say that asprin is insoluble in water. This confuses me because everything points to it being soluble. I believe it is soluble due to the -OH groups on the molecule that will create strong hydrogen bonds with water that will over power the bonds between individual asprin molecules casuing asprin to disolve in water. Also asprin has 2 -COOH groups, making it acidic. So does a proton also dissociate from the molecule creating an excess of hyrdonium ions making an acidic solution as well as creating hydrogen bonds or one or the other? Also the dipole-dipole moment around the Oxygen atom at the centre of the ester linkage adds to the solubility of the molecule.

any help or refrences to pages that can help me would be much appreciated.

[Borek]

Have you ever seen sugar (sucrose) crystals? I bet you did. Sucrose is not ionic, which doesn't stop it from being crystalline. Almost every substance can form crystals.

Aspirin is only slightly soluble in water (about 1g per liter). And you better check its formula - it doesn't have two -COOH groups.

[adam_goalietender]

thank you