Saturday, September 27, 2019
1. Continue Experiment #13: Extraction of harmala alkaloids from Peganum harmala seed powder using the method presented in "Extraction, Identification, and Quantification of Harmala Alkaloids in Three Species of Passiflora" by Abigail Frye and Catherine Haustein. American Journal of Undergraduate Research, Vol 6 No 3 pages 19 - 26.
- The aqueous layer was collected and a saturated sodium carbonate solution was added to neutralize the acid.
- The resultant solution was extracted three times with 100 mL ethyl acetate to remove the aqueous impurities.
- An attempt was made to recover alkaloids from this aqueous solution however it failed.
- The ethyl acetate washes were pooled and mixed with excess sodium sulfate was added to ensure the removal of excess water.
- The “dry” solution was poured through a glass funnel and cotton ball filter .
- The filtered solution was centrifuged to separate out the solid dispersed throughout the ethyl acetate.
- The solvent was then distilled off and the solid harmala alkaloids were recovered in an evaporating dish.
Thursday, September 26, 2019
1. Begin Experiment #13: Extraction of harmala alkaloids from Peganum harmala seed powder using the method presented in "Extraction, Identification, and Quantification of Harmala Alkaloids in Three Species of Passiflora" by Abigail Frye and Catherine Haustein. American Journal of Undergraduate Research, Vol 6 No 3 pages 19 - 26.
- 24.15 grams of dried seed powder was ground using a small coffee grinder and mixed with five times their weight of an acetic acid solution (3 grams of acetic acid per 100 mL of water; 0.5 M acetic acid).
- The acetic acid and plant material slurry was stirred for 15-20 minutes before being filtered using a Buchner funnel.
- Two washings of the plant material with the acetic acid solution were performed.
- Begin first extraction at 14:10 conclude at 14:30. Filter off solids and return to flask.
- Filtered off large particles first and then filtered off finer particulates using vacuum filtration.
- Begin second extraction at 15:07 and end at 15:24.
- Centrifuged filtered extracts at 4000 rpm for ~10 minutes.
- The aqueous plant extract solution was washed once with ~25 mL portion of petroleum ether and four times with 50 mL portions of ethyl acetate using a separatory funnel to remove the organic impurities.
- The aqueous layer was transferred to a 250 mL bottle well sealed with an inert plastic cap and this was put in the refrigerator to store overnight until the extraction was completed tomorrow.
Wednesday, September 25, 2019
1. Begin Experiment #12: Synthesis of indole-3-acetaldehyde (a.k.a. tryptaldehyde) by oxidation of tryptophan by hexacyanoferrate(III) (catalyzed normal stoichiometric mixture extracted with chloroform) 2 Trp + 2 HCF3- + 2 OH- → 2 I-3-A + 2 HCF4- + CO2 + NH3 + H2O
- In a 250 mL beaker one gram of tryptophan powder (204.229 grams per mole, 1 gram = 0.004896 moles) and 0.88 grams of KOH was combined with 1.22 grams of copper(II) sulfate pentahydrate (249.685 grams per mole).
- 100 mL of water was added to the beaker and stirring was turned on.
- Once everything had dissolved 1.65 grams of potassium ferricyanide was added to the mixture at 15:35. The solution turned yellowish-olive green.
- The ambient air temperature was 27 oC(+/-2oC). The solution temperature at 15:46 was 26 oC (+/-2oC). From this data it was concluded that no temperature change is observed from the reaction.
- The mixture was stirred for 30 minutes.
- At 16:06 the mixture was removed from stirring and transferred to a separatory funnel.
- The mixture was extracted with three 25 mL portions of chloroform which were drained into a 150 mL Erlenmeyer flask.
- A single extraction using xylene was then performed on the aqueous suspension.
- The chloroform extracts were combined and dried over anhydrous magnesium sulfate.
- The chloroform extract was filtered off and the solvent evaporated in an evaporating dish.
- The dried residue was reacted with Brady's Reagent to produce a vivid, red dinitrophenylhydrazone (pictured below). This was transferred to a test tube to allow it to settle out of solution.
- The xylene extraction was treated as were the chloroform extracts; being evaporated in an evaporating dish over boiling water after first being dried with anhydrous magnesium sulfate. No visible residue was apparent.
Tuesday, September 24, 2019
1. Begin Experiment #11: Synthesis of indole-3-acetaldehyde (a.k.a. tryptaldehyde) by oxidation of tryptophan by hexacyanoferrate(III) (uncatalyzed normal stoichiometric mixture combined with a hydrocarbon organic phase) 2 Trp + 2 HCF3- + 2 OH- → 2 I-3-A + 2 HCF4- + CO2 + NH3 + H2O
- To a 100 ml beaker was added 1 gram of tryptophan powder (204.229 grams per mole, 1 gram = 0.004896 moles) and 0.33 grams (0.005881 moles; 0.275 grams is 0.004896 moles) of potassium hydroxide along with 20 mL of distilled water at 14:53
- Next 1.65 grams of potassium ferricyanide (329.24 grams per mole; 1.65 grams is 0.0050115 moles) was weighed out and was added to the solution with stirring followed immediately by 25 mL of mixed xylenes. The mixture was stirred to maintain an intimate mixture of the two phases as the reaction proceeded. Being at 15:03.
- By 15:08 the xylenes have become slightly yellow in color when the stirring was paused just long enough to check it.
- At 15:40 about 10 mL more xylenes were added.
- The stirring was stopped at 15:54 and the xylenes and aqueous phases were allowed to fully separate.
- The aqueous phase was separated from the organic phase using a separatory funnel.
- A solution of saturated sodium bisulfite was prepared and the xylenes and were combined with about 25 mL of the bisulfite solution in a 150 mL Erlenmeyer flask. This was put on the stir plate and the stirring was turned up as high as it would go. Stirring began at 16:12.
- FAIL Destroyed by the acidity of the bisulfite? Or just too dilute? Or too much bisulfite solution? Or not there at all?
Sunday, September 22, 2019
1. Continue Experiment #10: Synthesis of indole-3-acetaldehyde (a.k.a. tryptaldehyde) by oxidation of tryptophan by hexacyanoferrate(III) (uncatalyzed normal stoichiometric mixture) 2 Trp + 2 HCF3- + 2 OH- → 2 I-3-A + 2 HCF4- + CO2 + NH3 + H2O
- The solids obtained yesterday dried overnight in the desiccator to produce a slightly blue-green solid that appears to be a mixture of a powder with needle-like crystals. The solids were weighed and were found to have a mass of 1.05 grams.
- Molar Mass of I-3-A = 159.1846 grams per mole.
- Molar Mass of I-3-A Sodium Bisulfite addition compound = 159.1846 + H + S +3O + Na → 263.2454
- Solubility of I-3-A in water (predicted by theory) = 2.948 grams per liter or 0.2948 grams per 100 mL at 25 oC.
- The I-3-A DNPHzone and the acetone DNPHzone were filtered out from their respective solutions.
- The solids were transferred to a 250 mL beaker equipped with a stir bar to which was added 20 mL of water. The suspension was stirred for about 5 minutes at room temperature which caused all of the solids to dissolve.
- 1.04 grams of sodium carbonate was weighed out and dissolved in 15.21 grams of water. This solution was then added to the I-3-A bisulfite addition compound. The solution immediately took on a orangish-brown color.
- The solution tested negative with Brady's Reagent. FAIL
Saturday, September 21, 2019
1. Begin Experiment #10: Synthesis of indole-3-acetaldehyde (a.k.a. tryptaldehyde) by oxidation of tryptophan by hexacyanoferrate(III) (uncatalyzed normal stoichiometric mixture) 2 Trp + 2 HCF3- + 2 OH- → 2 I-3-A + 2 HCF4- + CO2 + NH3 + H2O
- To a 100 ml beaker was added 1 gram of tryptophan powder (204.229 grams per mole, 1 gram = 0.004896 moles) and 0.31 grams (0.00552 moles; 0.275 grams is 0.004896 moles) of potassium hydroxide along with 20 mL of distilled water at 12:24.
- The solution was warmed and stirred until the tryptophan dissolved. Magnetic stirring was used to dissolve the bulk of the tryptophan powder but a glass rod was used to break up globs of tryptophan that floated on top of the solution and didn't dissolve. Eventually all of the tryptophan dissolved.
- The beaker containing the warm solution was covered with Parafilm and placed in a bowl of water with a few chunks of ice in it at 12:31 to cool back down to room temperature.
- Next 1.65 grams of potassium ferricyanide (329.24 grams per mole; 1.65 grams is 0.0050115 moles) was weighed out and was added to the solution with stirring at 13:53. The solution changed from the pale yellow of the deprotonated tryptophan to a very dark brown colored solution. This was allowed to stir.
- While the solution was stirring the Brady's Reagent was tested with an acetone control to establish the effectiveness of the reagent. 1/2 mL of acetone was dissolved in 10 mL of water and 1/2 mL of Brady's Reagent was then added to the tube. A brilliant yellow precipitate of acetone dinitrophenylhydrazone formed immediately thus establishing the efficacy of the reagent.
- At 14:13 a 1/2 mL aliquot of the reaction mixture was tested with Brady's Reagent. When prepared as the acetone was above there was no apparent precipitate but when the volume of the water was reduced to 3 mL and everything else kept the same the solution became hazy. The solution was allowed to continue stirring.
- When the tubes from step 6 were checked again at 14:20 is was observed that a solid substance was forming in the liquid which presumably is the dinitrophenylhydrazone of indole-3-acetaldehyde.
- The Bisulfite Reagent was prepared at 14:34 by dissolving 22.11 grams of sodium bisulfite into 50 mL of water with stirring (ambient air temperature is ~26 oC). Next 35 mL of absolute ethanol was added to the solution. Then 1.5 mL of water was added to produce a solution in which almost every particle of sodium bisulfite had dissolved. The reagent was finished being prepared at 14:45 and it was covered in Parafilm and put in a cooler of ice while I waited for the one hour reaction time to conclude.
- The reaction solution was transferred to a 250 mL beaker and after the previous beaker it was contained in was rinsed the total volume of the reaction solution had increased to approximately 40 mL. There was almost 100 mL of bisulfite reagent ready to be used.
- About 1/2 mL of the reaction solution was transferred to a test tube and about 1 mL of Brady's Reagent was added. Then water was added until the total volume reached ~4.5 mL at which point the I-3-A dinitrophenylhydrazone precipitated. It was also observed that this precipitation step can take several minutes to complete.
- At 14:57 the Bisulfite Reagent was added to the solution to precipitate the I-3-A bisulfite. However, there was no precipitate when the solution was added. I stirred the solution for several minutes and added in some excess sodium bisulfite to the solution to ensure that it was indeed saturated. However it still appeared that nothing precipitated.
- The beaker was covered with Parafilm and placed in a cooler of ice to sit for a while in the hopes that the aldehyde-bisulfite complex precipitates.
- The four test tubes containing the 2,4-DNP test samples all contained a good amount of a mid-tone orangish-brown precipitate which is presumably I-3-A dinitrophenylhydrazone. I am going to combine these, isolate the dinitrophenylhydrazone, and then find its melting point to confirm that I have I-3-A 2,4-DNPHzone. I am also going to test the acetone 2,4-DNPHzone control. That way I can be sure that I am going down the right path with this reaction.
- The solutions containing the I-3-A 2,4-DNPHzone were spun down in the centrifuge for 5 minutes at 4000 rpm to collect all of the solid material in one 50 mL beaker while separating it from most of the solution.
- The solution was tested on a concrete slab and some river stones after the dinitrophenylhydrazone had been centrifuged out. Both turned a mid to deep greenish blue.
- The 50 mL beaker containing the I-3-A 2,4-DNPHzone also had about 20 mL of the solution in it from transferring the solid I-3-A 2,4-DNPHzone from test tubes to the beaker. The beaker was covered and allowed to sit overnight so that all of the I-3-A 2,4-DNPHzone could settle out of suspension. I will isolate the dinitrophenylhydrazone tomorrow and after drying it I will test its melting point. I also saved the acetone 2,4-DNPHzone as a control sample to run a melting point test on as well.
- At 15:54 I checked the chilled reaction solution and there was a good amount of solid material in the solution. Of course at this early point there is no way to distinguish the bisulfite adduct of I-3-A from precipitated bisulfite. I filtered off this solid material (note that some of the solids were very fine and it is unlikely that I captured everything during this step) and dried it overnight in a desiccator over 3A molecular sieves.
Tuesday, September 17, 2019
1. Begin Experiment #9: Synthesis of indole-3-acetaldehyde (a.k.a. tryptaldehyde) by oxidation of tryptophan by hexacyanoferrate(III) (uncatalyzed normal stoichiometric mixture) 2 Trp + 2 HCF3- + 2 OH- → 2 I-3-A + 2 HCF4- + CO2 + NH3 + H2O
- To a 400 mL beaker was added 1 gram of tryptophan powder (204.229 grams per mole, 1 gram = 0.004896 moles) and ~0.3 grams (0.275 grams is 0.004896 moles) of potassium hydroxide along with 100 mL of distilled water. The solution was stirred until the tryptophan dissolved.
- Next 1.61 grams of potassium hexacyanoferrate(III) was added to the alkaline tryptophan solution with stirring at 12:01. Over the course of about one minute the solution darkened and became a very dark brown. The solution was stirred occasionally as it sat on the bench at the ambient temperature of 30 oC.
- Meanwhile the Bisulfite Reagent was prepared. oC
- Indole-3-Acetaldehyde = 159.1846 grams per mole. 0.004896 moles I-3-A is 0.7793 grams.
- Sodium Bisulfite = 104.061 grams per mole. 42 grams dissolves in 100 mL water at 25 oC..
- 0.779 grams of sodium bisulfite is 0.004896 moles
- 14.31 grams of sodium sulfite were dissolved in ~40 mL water. To this was added 25 mL of 95% ethanol.
- At 12:45 the bisulfate reagent was added to the solution which immediately became a light orange in color. However, no precipitate was produced. When the solution was tested for the presence of aldehyde with Brady's Reagent there was no positive test.
- Too much water! Do the reaction again in less water this time and then add an overwhelming amount of the reagent.
- Order more sodium bisulfite. This process goes through a lot of it!
- Explore direct extraction of I-3-A with diethyl ether, dichloromethane, or chloroform.
Friday, September 13, 2019
1. Conclude Experiment #7: Repeat Experiment #6 (with modifications) Synthesis of anthranilic acid from phthalimide (Source: http://www.prepchem.com/synthesis-of-anthranilic-acid/)
The dried anthranilic acid was weighed at 6.40 grams. According to the protocol with recovery of anthranilic acid from cupric anthranilate the yield of this synthesis should be 85%. The actual yield when accounting for anthranilic acid tied up as cupric anthranilate was 56.41%. The melting point of anthranilic acid is 146-148 oC. The product was 148-150 oC which given the variance of the thermometer of +/- 2 oC is exactly what it should be. So although the yield was low the product is highly pure. SUCCESS!!!
Phthalimide = 147.133 grams / mole
Anthranilic Acid = 137.138 grams / mole
Cupric Anthranilate = 335.8 g/mol
20 grams phthalimide = 0.139730 moles
0.139730 moles anthranilic acid = 19.16231756 grams anthranilic acid (theoretical)
85% of theoretical = 16.28796 grams
# moles cupric anthranilate in 3.42 grams = 0.010184633
moles anthranilic acid from Cu anthranilate = 0.02036926
0.02036926 moles anthranilic acid = 2.793 grams
Total grams anthranilic acid from anthranilic acid + anthranilic acid from cupric anthranilate = 9.193
9.19 / 16.29 0.56414 --> 56.41% yield based off total expected anthranilic acid and an 85% theoretical yield
Thursday, September 12, 2019
1. Continue Experiment #7: Repeat Experiment #6 (with modifications) Synthesis of anthranilic acid from phthalimide (Source: http://www.prepchem.com/synthesis-of-anthranilic-acid/)
- I recrystallized the crude anthranilic acid from 125 mL of boiling water.
- The now sparkling, brown crystals of anthranilic acid were collected by vacuum filtration and suction dried for a few minutes.
- The extremely light crystals were transferred to a coffee filter which was placed on folded paper towels in the desiccator over 3A molecular sieves.
Wednesday, September 11, 2019
1. Begin Experiment #7: Repeat Experiment #6 (with modifications) Synthesis of anthranilic acid from phthalimide (Source: http://www.prepchem.com/synthesis-of-anthranilic-acid/)
- 40 grams of sodium hydroxide was dissolved into 140 mL of distilled water. The flask was sealed with plastic wrap and put into a cooler of ice water to chill to ~ 10 oC. 200 grams of sodium hypochlorite was put in ice to chill while this was happening.
- After the temperature dropped to between 5-10 oC the phthalimide was added to the sodium hydroxide solution with vigorous stirring. The temperature of the solution increased to 27 oC before all of the phthalimide dissolved and approximately 100 mL of extra water was added during this process washing material that splashed onto the walls of the flask back down into the solution.
- Once the phthalimide dissolved the solution was chilled back to 10 oC.
- The chilled 200 mL of 5% sodium hypochlorite solution was added to the phthalimide solution. The resulting solution was allowed to stir for 15 minutes.
- The solution was heated to 80 oC after which it was removed from the heat and placed in ice water to chill back down to ~10 oC.
- The solution was then neutralized exactly with concentrated hydrochloric acid. As per ChemPlayer's suggestion I reserved ~40 mL of the solution in case I overshot the neutralization but it was not needed and this was retained for further experiments but later in the day I ended up discarding it after having concerns about the purity of the solution given the state of the crude product. The solution was almost colorless before the neutralization. It was a very, very pale yellow color. After the neutralization the solution looked like tea. This leads me to believe that an impurity was present in my HCl that discolored the solution and my eventual crude product.
- Once the solution was neutralized ~50 mL of glacial acetic acid was added to precipitate the anthranilic acid.
- The anthranilic acid was vacuum filtered from the solution. It was brown in color even after being washed with ~100 mL of ice water. The crude product has the appearance of a light, granulated brown sugar although it is much lighter.
- The filtrate was combined with a saturated solution of copper sulfate to precipitate remaining anthranilic acid which was a heavy emerald green solid. This was filtered out and the dark green solution of copper acetate and other contaminants was discarded.
- The crude anthranilic acid was put into the desiccator with freshly dried 3A molecular sieves overnight to dry. It had a dry weight of 7.27 grams.
- The copper anthranilate was put into the other desiccator with dried magnesium sulfate to dry overnight. It had a dry weight of 3.42 grams.
2. Begin Experiment #8: Repeat Experiment #5 (increase weights x2) Synthesis of indole-3-acetaldehyde [a.k.a. tryptaldehyde] by oxidation of tryptophan by hexacyanoferrate(III) catalyzed by Cu(II) ions (catalyzed and uncatalyzed normal stoichiometric mixture) 2 Trp + 2 HCF3- + 2 OH- → 2 I-3-A + 2 HCF4- + CO2 + NH3 + H2O (Repeat of Experiment #5)
- 0.5 grams of tryptophan was dissolved in 20 mL of water.
- 0.8 grams of potassium ferricyanide and 0.2 grams of KOH were added to the solution which went from yellow-orange to almost black in less than 1 second.
- The solution was stirred for about 15 minutes.
- The solution was decanted into two centrifuge tubes and spun at 4000 rpm for 5 minutes. A light gray solid separated (undissolved tryptophan? it dissolves only with difficulty so sonication of the tryptophan solution before use is probably a good idea in the future).
- A small aliquot was removed and tested with Brady's Reagent. The test was positive. The solid was dissolved in a small amount of water and also tested and this test was negative. The tryptaldehyde remained in the solution.
- The solution was extracted with ethyl acetate which was then allowed to partially evaporate.
- The solution was tested with Brady's Reagent and the test remained positive. The extract was diluted with water and tested and this test was negative. .
- A small amount of the product solution was spilled on the stones and it was noticed later that the stones had turned green. I tried this with a piece of quartz and it turned it blue and green as well. This color change appears to be semi-permanent. It does not wash off with water. This happened before and those stones remained green over a couple of weeks although the color faded over time.
Tuesday, September 10, 2019
1. Begin Experiment #6: Synthesis of anthranilic acid from phthalimide (Source: http://www.prepchem.com/synthesis-of-anthranilic-acid/)
- 20 grams of phthalimide was added to a 1000 mL beaker along with 140 mL of distilled water in an ice water bath.
- 40 grams of NaOH was added slowly with stirring. Once completed a cloudy white solution with an oily consistency was achieved. It was hard to maintain cooling during this part of the operation and the temperature on the solution reached as high as 40 oC.
- 200 mL of 5% sodium hypochlorite solution was added to the solution. A white precipitate formed as the hypochlorite was added.
- The beaker was removed from the ice bath and placed on the hot plate. With stirring the solution was heated to 80 oC.
- Once the solution reached the required temperature it was removed from the hot plate and was then placed on a rack to cool for about 10 minutes.
- The beaker was then put in an ice bath until the temperature had dropped to 20 oC.
- Using a glass rod to stir the mixture concentrated HCl was added until the solution was neutralized.
- I slightly overshot it and the solution became slightly acidic. The solution rapidly darkened at this point.
- The solution was divided into two portions each about 300 mL in volume.
- One portion was combined with copper sulfate which produced a grayish olive green precipitate. When combined with sodium sulfide this precipitate reacted to form black copper sulfide which precipitated leaving a dark yellowish solution. This is suggestive of the chemistry of anthranilic acid.
- To the second portion was added 200 mL of acetic acid. This did not result in the precipitation of a solid as was supposed to happen. After heating the solution a precipitate formed. This was collected and dried and the attempt was made to recrystallize this product from boiling water. This attempt failed.
- FAIL. Changes to make to the protocol based on observations of the reaction and ChemPlayers video (https://www.bitchute.com/video/lt07v5I2lSEp/)
- Prepare the initial solution of NaOH first and then chill to 10 oC before adding in the phthalimide. The final solution should be clear. Add water if necessary.
- I was right in adding all the NaOCl at once. However, chill the NaOCl first to 10 oC.
- Temp will then rise to about 40 oC.
- After heating allow to cool down and then chill. Separate out a small amount of product in case you overshoot the neutralization.
- The neutralized solution should be a yellow color.
- Add acetic acid slowly.
- Once the acetic acid is added the solution will be a dark brown color.
Monday, September 9, 2019
1. Conclude Experiment #4: Synthesis of succinimide from succinic acid and ammonia (Source: http://www.prepchem.com/synthesis-of-succinimide/)
- 31 grams of ammonium succinate was transferred into a 50 mL thick walled round bottom flask. This was connected to a 400 mL liebig column running room temp water by a small tube of aluminum foil. This was done so that if the flask cracked from the heat the condenser column would not be damaged (this idea actually worked well).
- A bunsen flame was applied in an attempt to thermally decompose the ammonium succinate and produce succinimide. However, the ammonium succinate merely melted and water of crystallization was given off which dripped back down from the condenser. This caused the flask to crack but not shatter.
- In the end nothing was achieved. While the condenser did fill with a white smokey substance nothing condensed on the walls. Even after the addition of ice no sublimate was collected. FAIL
- Dry the ammonium succinate more thoroughly and try again with a different apparatus.
Thursday, September 5, 2019
1.Continue Experiment #4: Synthesis of succinimide from succinic acid and ammonia (Source: http://www.prepchem.com/synthesis-of-succinimide/)
- I continued evaporating the combined ammonium succinate and succinic acid solutions over boiling water. This process took the entire day. I found that it helps to clear the crystal crust the evaporating solution forms on the surface. This allows the water in the evaporating dish to evaporate more easily.
- Once the ammonium succinate was completely dry it was transferred to a mason jar which was tightly sealed. I will keep it stored like that until I am ready to complete the experiment.
2. Begin Experiment #5: Synthesis of indole-3-acetaldehyde [a.k.a. tryptaldehyde] by oxidation of tryptophan by hexacyanoferrate(III) catalyzed by Cu(II) ions (catalyzed and uncatalyzed normal stoichiometric mixture) 2 Trp + 2 HCF3- + 2 OH- → 2 I-3-A + 2 HCF4- + CO2 + NH3 + H2O
- In 2 beakers 0.25 grams of tryptophan (0.0012241 moles) were combined with:
- 0.40 grams potassium ferricyanide (0.45 uncatalyzed, 0.41 catalyzed)
- 0.068 grams KOH
- To the beaker of the catalyzed reaction mixture was added 0.06 grams CuSO4•5H2O
- To these beakers was added 20 mL of distilled water and each was allowed to stir for 10 minutes before the stirring was stopped and the contents of the beakers was allowed to settle.
- Begin stirring uncatalyzed reaction at 16:25 and end at 16:35. Allow homogenous solution to sit on bench afterwards.
- Begin stirring catalyzed reaction at 16:43 and end at 16:48. Allow homogenous solution to sit on the bench afterwards.
- In order to remove any solid particulates both solutions were decanted into a 15 mL plastic tube with a screw on cap (the excess was discarded) and centrifuged at 4000 r/min for 5 minutes. Both solutions looked the same: an opaque, very dark brown bordering on black.
- It was noted when transferring the solutions to the plastic tubes that the catalyzed reaction had a fair amount of a dark brown solid that had settled to the bottom of the beaker.
- It was also noted that there was some solid material in the uncatalyzed reaction beaker as well but only a very tiny fraction of that present in the catalyzed reaction beaker.
- Once the solutions were centrifuged they were transferred to glass test tubes. ~1 mL of Brady's Reagent was added to each tube. Strangely with the uncatalyzed reaction a dark yellow/light brown precipitate was produced immediately SUCCESS! but with the catalyzed reaction it appeared that no precipitate was produced. However, when I centrifuged down the dinitrophenylhydrazone in the uncatalyzed mixture I balanced it out with the catalyzed mixture and it was then that I discovered that a dinitrophenylhydrazone HAD been produced but it was a very dark rusty red color.
- Addendum: September 7, 2019
- The dark red dinitrophenylhydrazone turned black between the time it was produced and 18:30 this evening. I was saving both dinitrophenylhydrazones to test their melting points but an accident occurred and both were lost. That's OK though since this is an easy experiment to repeat.
Wednesday, September 4, 2019
1. Begin Experiment #4: Synthesis of succinimide from succinic acid and ammonia (Source: http://www.prepchem.com/synthesis-of-succinimide/)
- 20 grams of succinic acid were dissolved in 200 mL of water.
- The solution was neutralized by addition of roughly 15 mL of concentrated aqueous ammonia solution.
- The solution was boiled down from ~225 mL in volume to ~200 mL and the ammonia smell had become very mild.
- While the excess ammonia was being expelled another solution of 20 grams of succinic acid in 200 mL of water was prepared.
- Once the excess ammonia was expelled (so far as I could tell) the two solutions were combined.
- The combined solutions were mixed thoroughly and then split up into smaller portions to be evaporated in a boiling water bath. Unfortunately I fell asleep while this was happening and the water in one boiling water bath boiled dry. The beaker was not touching the bottom of the pot but the radiant heat boiled off a large part of the solution. However, it did not boil dry before I woke up and removed it from the heat so the temperature of the solution never exceeded 100 oC.
Monday, September 2, 2019
1. Conclude Experiment #3: Synthesis of indole-3-acetaldehyde [a.k.a. tryptaldehyde] by oxidation of tryptophan by hexacyanoferrate(III) catalyzed by Cu(II) ions (optimum catalyzed reaction rate stoichiometry).
- When checked at 06:30 the slightly dark medium solid had largely settled out of the solution which was yellowish-orange brown color.
- Filtered the mixture.
- The large amount of precipitate in the mixture made filtration extremely difficult. In the future it may be best to centrifuge the solids out rather than try to filter them.
- Tested the filtrate with Brady's Reagent. The test was negative.
2. Prepared Brady's Reagent as described in the grimoire.
Sunday, September 1, 2019
1. Begin Experiment #3: Synthesis of indole-3-acetaldehyde [a.k.a. tryptaldehyde] by oxidation of tryptophan by hexacyanoferrate(III) catalyzed by Cu(II) ions (optimum catalyzed reaction rate stoichiometry). Based on "Copper(II) catalysis for oxidation of L-tryptophan by hexacyanoferrate(III) in alkaline medium: a kinetic and mechanistic approach" by Basim H. Asghar, Hatem M. Altass, Ahmed Fawzy, 2015
- Molar Mass of Tryptophan = 204.23 g/mol
- Molar Mass of Potassium Ferricyanide = 329.24 g/mol
- Molar Mass of Potassium Hydroxide = 56.1056 g/mol
- Molar Mass of Copper Sulfate Pentahydrate = 249.685 g/mol
- Molar Mass of Potassium Perchlorate = 138.55 g/mo
- Molar Mass of Indole-3-Acetaldehyde = 159.188 g/mol
Reaction: 2 Trp + 2 HCF3- + 2 OH- → 2 I-3-A + 2 HCF4- + CO2 + NH3 + H2O
To obtain optimum kinetics the paper suggests that the following compounds be present in these molar ratios: 7 HCF3-, 2 Trp, 2 OH, 5 Cu2+, and 2 ClO4-
- 0.4085 grams of Tryptophan = 2 mmol (0.002 moles)
- 2.3047 grams HCF3- (0.007 moles)
- 0.1122 grams KOH (0.002 moles)
- 1.2484 grams CuSO4•5H2O (0.005 moles)
- 0.2771 grams KClO4 (0.002 moles)
- Everything but potassium hydroxide was combined in one beaker and ~50 mL of deionized water was added and stirring was begun. Small chunks of something dissolved only slowly and with some small difficulty. In the future pre-dissolving the tryptophan may be useful.
- Then the potassium hydroxide was dissolved in ~20 mL of water and was combined with the other solution. Stirring was begun.
- Within ~23 minutes the solution had turned from a transparent very slightly orangey-brown to an opaque slightly dark brown.
- Left to sit on the bench covered with a watch glass at 17:30.
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