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Solubility book (3rd Edn)
Measuring the solubility of 1-adamantylamine and 6-aminocaproic acid in ethanol and methanol
This experiment seeks to measure the solubility of 1-adamantylamine and 6-aminocaproic acid in ethanol and methanol. The experiment will also be added to with the solubility in THF at a later stage (slight hitch occurred - bottle lid stuck fast).
Jenny please add your experiment to the "list of experiments" page as soon as you create a new one JCB
Four 2 mL screwcap vials were labelled with their intended contents. Four 1.5 mL microcentrifuge tubes (Eppendorfs) were labelled and weighed. 750 µL of ethanol was added to each respectively labelled tube. Likewise 750 µL methanol was added to two respectively labelled tubes. Four small narrow spatula scoops of 1-adamantylamine were added to a tube of ethanol. The tube was vortexed for 1 minute in 10 second intervals to leave a milky white translucent product. Six small scoops of powder added and vortexed for 1 minute. Realised that adamantylamine is insoluble and I had a fine suspension. The process was repeated with adamantylamine in methanol, again leaving a fine suspension.
This process again repeated for 6-aminocaproic acid in ethanol and methanol. The saturated/insoluble solutions were centrifuged for 1 minute in an Eppendorf 5415D centrifuge at 13,200 rpm/16,100 g. 500 µL of each supernatant was added to it's respectively labelled eppendorf and then dried by speedvac, initially for 3 hours. The samples were weighed and returned to the speedvac for further drying for approximately 45 minutes.
The spreadsheet of results can be found here
Tuesday 25.11.08 GMT
10.15 - Recorded mass of empty Eppendorfs.
10.22 - Added 750 µL of ethanol and methanol to 2 mL microcentrifuge tubes.
10.24 - Added 4 small narrow spatula scoops of adamantylamine to ethanol. Vortexed for 1 minute in 10 second intervals.
10.26 - Dissolved to leave milky white translucent product.
10.28 - Added 6 small scoops of adamantylamine and vortexed for 1 minute in 10 second intervals as before.
10.30 - Debated whether adamantylamine in ethanol produces a solution or a suspension/emulsion.
10.32 - Sought advice and concluded it was a suspension/emulsion.
10.34 - Added 4 small spatula scoops of adamanylamine to methanol. Vortexed for 1 minute in 10 second intervals.
10.36 - Added 4 small spatula scoops of adamanylamine and vortexed for 20 seconds
10.37 - Decided this sample was also a suspension/emulsion.
10.39 - Added 4 small spatulas of 6-aminocaproic acid to ethanol. Vortexed for 1 minute in 10 second intervals. Powder remaining.
10.42 - Added 4 small spatulas of 6-aminocaproic acid to methanol. Vortexed for 1 minute in 10 second intervals. Powder remaining.
10.44 - Vortexed 6-aminocaproic acid in ethanol for 2 minutes in 10 second intervals. Decided it was definitely saturated/insoluble.
10.47 - Vortexed 6-aminocaproic acid in methanol for 2 minutes in 10 second intervals. Decided it was definitely saturated/insoluble.
10.50 - Centrifuged for 1 minute.
10.52 - Transferred 500 µL of each supernatant to its respective eppendorf.
10.55 - Placed samples on speedvac and put under vacuum.
13.55 - Retrieved samples from speedvac.
13.57 - Measured masses and recorded appearance of samples.
14.05 - Returned samples to speedvac.
14.51 - Samples removed from speedvac.
14.52 - Samples weighed.
Neither 1-adamantylamine nor 6-aminocaproic acid were particularly soluble in ethanol or methanol. Despite producing a product that had the appearance of a suspension, the 1-adamantylamine was found to be more soluble than expected in both methanol and ethanol. My concern with the adamantylamine results is despite vortexing and appearing to be producing an insoluble suspension, it was actually dissolving and the numbers do not reflect the true solubility. However, on centrifuging, there was a reasonable amount of powder remaining in the tube.
I think that judging the structures of these compunds that it is possible that the adamantylamine may be more soluble in THF.
The yellow colour returned back from the residue of 6-aminocaproic acid in ethanol (reported in spreadsheet) does concern me as the 6-aminocaproic acid started as a white powder. It is possible that small amounts of dust from the yellow compounds of two weeks ago could be remaining in the speedvac. I will clean it out to make sure.
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