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The Synthesis of Aqua Regia

Rxn 1. HNO3 + HCl → NOCl + 2H2
Rxn 2. 2NOCl 2NO + Cl2

Combine the acids together in the correct proportions and mix thoroughly. The acid solution will change to a golden yellow or orangish color. Once this is complete the Aqua Regia is ready for use. Aqua Regia must always be made fresh before use as it rapidly decomposes over a matter of hours.

Piranha Solutions - Acidic and Basic

Ensure that minimal residue remains on the glassware. Add the hydrogen peroxide to the sulfuric acid or concentrated ammonia (not the other way around) with good stirring to prevent temperature spikes that could cause boiling. Always prepare fresh before use. 

Chromosulfuric Acid Solution for Cleaning Glassware

Combine the chromate salt with enough distilled water to make a paste. Slowly add the sulfuric acid to the paste and stir until an homogenous paste forms. The chromic acid wash is used to decompose organic residues  as well as some mineral deposits. Use this wash until it turns green (CrVI → CrIII). Heavily soiled items may need soaking overnight to be cleaned. Use of this wash will contaminate glassware with heavy metal ions which may interfere with some experiments.  Chromic acid burns are treated with dilute aqueous solutions of sodium thiosulfate.

Synthesis of Elemental Iodine (Source: NurdRage)

2HCl + 2KI + 2H2O2 → I2(s) + 2KCl + 2H2O + Δ

  1. Add the KI to a 150 mL beaker and dissolve it into 10 mL of distilled water with gentle heating.
  2. Add the concentrated HCl to the solution in the beaker with stirring. A pale yellow suspension will form.
  3. Slowly add the hydrogen peroxide to beaker with stirring. This reaction is exothermic and care should be taken to minimize the formation of I2 vapor.
  4. The solid iodine is filtered off and washed once with ice water.
  5. The iodine is dried on top of some folded paper towels before being pressed between more folded paper towels to dry it as much as possible and squeeze the iodine into solid chunks.
  6. The iodine is then placed into a clean beaker and enough 98% sulfuric acid is added to cover the iodine.
  7. The beaker is heated until the iodine melts. The melt is allowed to sit under the hot, concentrated sulfuric acid for a short time before the heat is turned off.
  8. The sulfuric acid is decanted and as it will be full of iodine crystals is saved for iodine recycling. The chunks of iodine are dried and bottled.

Synthesis of Azeotropic Nitric Acid (Source: Nile Red)

KNO3 + H2SO4 → KHSO4 + HNO3

 

  1. Set up for distillation using a 300mm or longer Liebig condenser cooled with ice water. The use of a short Vigreux column is recommended to capture sulfuric acid aerosols which will contaminate the crude product. These aerosols are kicked up by stirring and boiling of the reaction mixture and thus are to some extent unavoidable.
  2. Dissolve the nitrate salt into the water in a one liter boiling flask.
  3. With strong stirring slowly and carefully add the 98% H2SO4 to the nitrate solution. Connect the boiling flask to the distillation train.
  4. Turn on slow stirring and high heat. At first dilute nitric acid comes over at a temperature near the boiling point of water. The total amount of dilute nitric acid that distills over is about 175-200 mL.
  5. Next concentrated nitric acid comes over. The temperature will rise to about 121oC and brown NO2 gas will fill the distillation apparatus. The total amount of concentrated nitric acid that distills over is 175-200 mL.
  6. Once the distillation is complete about 400 nmL of ~30% nitric acid will be in the receiver. This nitric acid will be contaminated to some degree with sulfuric acid. If desired this can be tested for by combining a few drops of the distillate with a few drops of aqueous barium nitrate. A white precipitate indicates the presence of sulfate ion.
  7. Fractionally distill the distillate using a 400 mL Vigreux column and collect that portion that comes over above 120.5 oC. This will be the azeotropic nitric acid. 

Synthesis of Fuming Nitric Acid (Source: Nile Red)

KNO3 + H2SO4 → KHSO4 + HNO3
 

Distill this as described in the azeotropic nitric acid synthesis above. Pure HNO3 boils at 83 oC and is degraded by heat. The yield of fuming nitric acid is approximately 25 mL to 30 mL. This can be fractionally distilled itself if sulfuric acid contamination is a problem. This can be tested for as described under the azeotropic nitric acid synthesis however in this instance the filtrate should be diluted with 5 times it's volume in water and then tested with barium nitrate solution. The reason for the dilution is that barium sulfate is soluble in concentrated strong acids so they must be diluted before testing. Red fuming nitric acid can be converted to white fuming nitric acid by removing dissolved NOx species at reduced pressure. To carry out this operation the red fuming nitric acid is subjected to a pressure of 200 mmHg (26.664 kilopascals) for 10 to 30 minutes.

Synthesis of Potassium Iodate (Source: ChemPlayer)

Net Equation: 2KClO3 + I2 → 2KIO3 + Cl2(g)

 

  1. Dissolve the potassium chlorate into the water. Heating will be necessary and the temperature shoud be about 80 oC by the time the potassium chlorate dissolves.
  2. Add the I2 crystals to the KClO3 solution followed by the azeotropic HNO3 catalyst. The solution should turn a browish purple color.
  3. Add a stir bar to the flask and cover the flask to prevent I2 from escaping.
  4. Stir the mixture and maintain it at temp of 88 oC. Do not allow the temp to exceed 90 oC as unwanted side products will form (i.e. ClO4 from the disproportionation reaction of ClO3-)
  5. Once all of the iodine has reacted the solution will become clear. Uncover the flask and allow the solution to boil for 5 minutes to drive out the Cl2 produced by the reaction
  6. Remove the solution from heat, cover the flask with plastic wrap, and place it in an ice bath that has been salted with NaCl.
  7. Add flakes of solid KOH bit by bit until the solution is weakly alkaline in order to neutralize the iodic acid which is the actual product of the reaction. 
    1. NaOH should not be used in place of KOH.
  8. Chill the mixture to approximately 2 oC and filter out the precipitate using vacuum filtration.
  9. Wash the precipitate sparingly with ice water and dry the product as much as possible. Save the filtrate for a second round of crystallization.

Recycling of Silver Metal 

  1. Take the raw material containing the silver to be recycled and boil it in the nitric acid until all of the silver has been converted to silver nitrate.
  2. Filter off the silver nitrate extract.
  3. Add enough of the NaCl solution to precipitate all of the silver as silver chloride.
  4. Allow the silver chloride to settle out of the liquid and decant off all but the top 2-3 cm of the clear water from above the precipitate.
  5. With stirring slowly add solid flakes of NaOH to the liquid in which the silver chloride is suspended. The end point is reached when no more black disilver monoxide is produced.
  6. Add the finely powdered sucrose to the still stirring liquid to precipitate silver metal powder.

Synthesis of Elemental Bromine  (Source: Nile Red)

TCCA + 6NaBr + 3H+  Cyanuric Acid + 3Br2 + 3Cl-+ 6Na+

  1. Combine the H2O, NaBr, and TCCA in a one liter flask. Set up for simple distillation and lute the joints of the apparatus with 98% sulfuric acid. 
  2. After thoroughly stirring the contents of the flask into a homogenous mix add the HCl to the flask. Quickly attach the boiling flask to the distillation train and add ice to the coolant reservoir if it has not already been done. 
  3. The heat is turned on high and the distillation is continued until the red color has left the boiling flask. The material in the flask should be a pale yellow when the distillation is completed. 
  4. The distillate is transferred to a separatory funnel and the bottom layer of Br2 is drained off into another separatory funnel. 
  5. Add 25 mL of 98% H2SO4 to the Br2 in the separatory funnel. Close the flask, shake gently, and vent frequently to avoid pressure building up in the flask. As the process continues less and less vapor is generated and the ventings become less energetic but do not neglect venting the flask for any reason. 
  6. Allow the contents of the funnel to settle and separate thoroughly. The dry dibromine is drained into a bottle specifically designed to hold volatile, reactive chemicals or it is partitioned into glass ampoules. 

Synthesis of Hydrobromic Acid #1 (Source: NurdRage)

NaHSO4 + NaBr  HBr(aq) + Na2SO4

  1. Combine all of the reagents into a beaker and stir until all of the granules are dissolved. If some cloudiness remains that is alright so long as the granules dissolve. Heating will facilitate dissolution.
  2. After all of the solids dissolve cover the beaker with plastic wrap and chill overnight. This will precipitate the sodium sulfate product of the reaction which has a low solubility at low temperatures. 
  3. Filter out the liquid and then distill its entire volume to remove the remaining Na2SO4 and isolate the aqueous HBr. 
  4. Fractionally distill the distillate taking care not to overheat and degrade the azeotropic HBr. 

Azeotropic HBr boils at 124.3 oC at STP and corresponds to a concentration of 47.6% HBr by weight. Its density is 1.486 grams / mL. Hydrobromic acid may be kept colorless for long periods of time by storage in a dark bottle in the refrigerator.

Synthesis of Hydrobromic Acid #2 (Source: PrepChem.com)

Rxn 1. 2S + Br2 → S2Br2
Rxn 2. S2Br2 + 5Br2 + 8H2O → 12HBr + 2H2SO4

  1. One hundred and fifty grams of bromine are weighed into a glass-stoppered bottle in the hood and 10 g of powdered sulfur are quickly introduced. The bottle is then agitated and the sulfur rapidly dissolves to yield a red oily liquid.
  2. Two hundred grams of ice are placed in a 500 ml glass-stoppered bottle and the vessel is immersed in ice. About one-third of the sulfur-bromine mixture is added; over the course of about one hour the red oil disappears. Cooling in plain water is maintained throughout the hydrolysis. 
  3. The second third of the sulfur-bromine compound is now added, followed by the last portion about 30 minutes later.When all the mate­rial has dissolved and reacted, a pale yellow liquid remains which is fractionally distilled as usual. Yield is about 300 g of HBr. 

Synthesis of Potassium Bromate and Potassium Bromide (Source: PrepChem.com)

Rxn 1. Br2 + OH- → Br- + H2O + BrO-
Rxn 2. 3BrO- → 2Br- + BrO3-

  1. Combine the KOH and the 200 mL of water in a one liter beaker. Cool the resulting 5M KOH solution to room temperature. 
  2. Turn on stirring and begin adding the bromine in ~1 mL increments. On the first addition the solution turns yellow. Afterwards it will turn red as a portion of Br2 is added before quickly changing back to yellow. At the end of the reaction the red color will remain and this will be followed shortly by the precipitation of KBrO3.
  3. The solution is then heated to boiling to expel excess bromine. The yellow color will remain but the smell of bromine diminishes. 
  4. Once this is completed transfer the beaker to an ice bath and cool the contents to 10 oC. 
  5. Obtain the crude potassium bromate by filtration. Save the filtrate for the KBr synthesis. 
  6. Dissolve the potassium bromate in four times its mass of boiling water and then chill back to 10 oC. Filter the recrystallized KBrO3 and dry. Make sure to save this filtrate as well for the KBr synthesis.
  7. If an even higher purity is desired repeat the recrystallization steps. To test the KBrO3 for purity take a drop of an aqueous solution of the potassium bromate product and add a drop of aqueous silver bromide to it. If KBr is still present a white precipitate of AgBr will form. 
  8. Combine the filtrates from steps 5 and 6 and boil the solution down to a white, salty paste. 
  9. Mix the paste with the powdered charcoal and "heat to redness in an iron crucible for 20 minutes". This will not only destroy the KBrO3 contaminant in the filtrate paste but it will also convert it into KBr thus increasing the yield of the KBr product. The KBr/KBrO3/charcoal mix will start off black but by the end of this calcination step it will have been converted into a grayish-white solid. 
  10. Allow the solid material in the crucible to cool to room temperature and then mix it with water. This mix is boiled for ~5 minutes and then filtered to remove all particulates suspended in the solution.
  11. Boil the filtrate down to obtain crude KBr crystals. These crystals should be tested for the presence of bromate.
    1. To do this add a drop of 98% sulfuric acid to a few drops of the hot, concentrated filtrate. An orange color caused by the formation of Br2 is a positive test for bromate.
    2. Another test for bromate is to combine a few drops of a cold, concentrated solution of the KBr product with a few drops of BaCl2 solution. A white to slightly yellow precipitate confirms the presence of bromate. 
  12. The KBr crystals can be further purified if necessary by grinding the crystals up, combining them with 10 grams of charcoal, and repeating steps 9 through 11. Once the crude KBr has been established to be free of bromate it can be recrystallized from distilled water. 

Synthesis of Alkyl Nitrite Esters (A General Reaction Illustrated with n-Butyl Nitrite) (Source: DougsLab)

CH3CH2CH2CH2OH + HNO2 → CH3CH2CH2CH2O-N=O + H2O

  1. Chill the HCl and the 70% butanol solutions down to ice cold. Transfer the cold BuOH to an ice bath equipped with magnetic stirring.
  2. Slowly add the sodium nitrite to the chilled alcohol and allow the mixture to stir. The sodium nitrite may or may not fully dissolve.
  3. Add the HCl solution to the chilled alcohol solution ~0.5 mL at a time with vigorous stirring. The addition of the HCl produces blue nitrous acid which disappears as it reacts with the alcohol to produce the nitrite ester. 
  4. Stir for 5 to 10 minutes after adding all of the HCl.
  5. Transfer as much of the oil and as little of the solid as possible to a separatory funnel containing 40 mL of distilled water. 
  6. Swirl gently and then drain the water layer and discard.
  7. Add the saturated NaCl solution to the separatory funnel and swirl gently several times in order to remove water from the alkyl nitrite. Be careful not to vaporize the product on the room temperature walls of the separatory funnel. 
  8. Drain the sodium chloride solution completely and transfer the n-butyl nitrite to an air-tight amber bottle 

Synthesis of Ammonium Metavanadate (Source: NileRed)

Rxn 1. V2O5 + Na2CO3 + Δ → NaVO3 + CO2
Rxn 2. NaVO3 + NH4Cl → NH4VO3(s) + NaCl(aq)

  1. Prepare the sodium carbonate solution and heat it to 90 oC.
  2. Add the V2O5 to the solution slowly to minimize CO2 production. 
  3. Add about 150 mL of water to the mixture. The solution should have a yellow color at this point.
  4. Filter the solution into a clean beaker.
  5. Add the ammonium chloride solution to the filtrate. 
  6. Stir thoroughly and allow the solution to cool. Cover the beaker and chill the solution to precipitate the ammonium metavanadate. This precipitation step can take several days to complete.
  7. If crystallization does not occur after a few days add about 5 grams of ammonium chloride to the solution with stirring. 
  8. Chill the filtrate on ice.
  9. Filter off the product and wash with ice water. The NH4VO3 tends not to crystallize without having to carry out step 7. It appears as a whitish crust on the beaker walls. Dry the product and store normally.

Dragendorff's Reagent

Stock Solution: Dissolve the KI into 50 mL of water to create a 50% solution. In a separate beaker dissolve the bismuth subnitrate into the 20 mL of glacial acetic acid and 80 mL of water. Combine this with the KI solution and transfer the stock solution to an amber bottle for storage. This stock will keep indefinitely if well stored.
Working Solution: Combine 10 mL of the stock solution with 20 mL of glacial acetic acid and then bring up to a total volume of 100 mL with distilled water.

Dragendorff's Reagent is potassium tetraiodobismuthate (CAS 41944-01-8). It reacts with tertiary amines to form an insoluble complex which manifests as an orange to yellow precipitate. The reagent can be tested before analytical use by reacting it with a sample of nicotine (bright orange ppt), triethylamine (bright orange ppt) and a sample of hexamine (bright yellow ppt).

Beam's CBD Reagent (Source: Wikipedia)

This reagent is made up by dissolving 5% KOH in 95% ethanol.

Solid samples should be finely divided before testing. Place the sample in a test tube and add a few milliliters of the reagent. Samples containing CBD will exhibit a purplish color after approximately 10 minutes. Temperature extremes will have an effect on the time needed for the reaction to occur. This test is specific to CBD and THC does not react.

0.01N Dimethylglyoxime and 0.5 M Dimethylglyoxime in 1 M NaOH

Dissolve 0.6 grams of dimethylglyoxime in 500 mL of 95% ethanol to produce the 0.01N solution. This reagent forms a bright red complex with nickel ions and a yellow complex with palladium ions. In acidic solutions palladium can be precipitated selectively from nickel whereas in alkaline solutions nickel will precipitate. When the goal is to precipitate palladium from other noble metals an aqueous dimethylglyoxime solution in NaOH is usually preferred. To prepare a 0.5 molar dimethylglyoxime solution in 1M NaOH start with 4g NaOH dissolved in 100 ml distilled water, then add 5.81 g dimethylglyoxime and filter when it has dissolved. To precipitate 1.00 g of palladium 2.5 grams of dimethylglyoxime is used and this corresponds to 43 ml of the above alkaline solution. When using the alkaline solution the pH value of the sample containing the dissolved palladium cations must be kept acidic to keep nickel from precipitating if it is present.

Marquis' Reagent (Source: Wikipedia and experimental data)

Dissolve 10 mL of 37% formaldehyde in 50 mL of 98% H2SO4. An alternate formulation is 5 ml of 40% formaldehyde in 95-98% H2SO4. Methanol may be added to slow down the color changing polymerization reaction. Hup.org Color change table for Marquis' Reagent.

  1. The Marquis' Test results develop very quickly and due to reactions with moisture and oxygen in air. Any changes after the first 60 seconds should be discarded (note that this window may need to be adjusted if methanol was added to slow down the reaction). If the reagent is to be kept for any period of time it should be stored in a freezer in order to maximize shelf life. The reagent can be tested before analytical use by reacting it with a small sample of two or more of the following:
    1. Acetylsalicylic Acid (Aspirin) = Bright Red
    2. Ascorbic Acid (Vitamin C) = No Reaction
    3. Granulated Sugar = Brown  → Rapid Black
    4. Butylated Hydroxytoluene = Brown → Rapid Reddish-Black
    5. Disodium EDTA = No Reaction
    6. Triphenylphosphine = No Reaction
    7. Tryptophan = Brown → Rapid Black
    8. Camphor = Bubbling → Rapid Brownish-Yellow
    9. Indole-3-Acetic Acid = Yellow  → Dark Brown
    10. Hydroquinone = Brownish-Black
    11. Sodium Chloride = Bubbling 
    12. Dimethylglyoxime = Slow Orange
    13. para-Dimethylaminobenzaldehyde = Dissolves but no reaction. 
    14. Hexamine = No reaction.
    15. Phenylacetic Acid = Rapid Yellow → Orange  → Brown  → Dark Brown
    16. Nicotine = No Reaction

Mandelin's Reagent (Source: Wikipedia and experimental data)

Dissolve 0.5-1 grams ammonium metavanadate in 100 mL of 95-98% H2SO4. This reagent has a strong orange-yellow color before use. Hup.org Color change table for Mandelin's Reagent.

  1. The reagent can be tested before analytical use by reacting it with a small sample of two or more of the following:
    1. Acetylsalicylic Acid (Aspirin) = Dark Greenish-Black
    2. Ascorbic Acid (Vitamin C) = Light Blueish Green
    3. Granulated Sugar = Brown → Black
    4. Butylated Hydroxytoluene = Brown → Dark Brown/Black → Dark Reddish Black
    5. Disodium EDTA = No Reaction
    6. Triphenylphosphine = Dark Yellow → Brown
    7. Tryptophan = Dark Orange/Black
    8. Camphor = Reacts (Bubbling)/Rapid Dirty Yellow → Brown 
    9. Indole-3-Acetic Acid = Brown → Rapid Black
    10. Hydroquinone = Rapid Brownish Black
    11. Sodium Chloride = Reacts with bubbling, foaming and evolution of heat but no color change.
    12. Dimethylglyoxime = Greenish-Brown
    13. para-Dimethylaminobenzaldehyde = Rapid Black → Very Rapid Brown → Yellowish-Brown
    14. Hexamine = Reacts with mild bubbling → Rapid Yellow Rim With a Sea-Green Center

Mecke's Reagent (Source: Wikipedia and experimental data)

Dissolve 1 gram of selenious acid or 1.34 grams of sodium selenite in 100 mL 95-98% H2SO4Hup.org Color change table for Mecke's Reagent.

  1. The reagent can be tested before analytical use by reacting it with a small sample of two or more of the following:
    1. Acetylsalicylic Acid (Aspirin) = Dark Yellow
    2. Ascorbic Acid (Vitamin C) = Reacts to produce red selenium with generation of gas.
    3. Granulated Sugar = Greenish-Yellow → Rapid Orange → Slow Black
    4. Butylated Hydroxytoluene = Greenish-Yellow → Rapid Orange → Slow Black
    5. Disodium EDTA = No Reaction
    6. Triphenylphosphine = Slow Pale Pink
    7. Tryptophan = Black → Rapid Black Orange
    8. Camphor = Reacts with bubbling and gives Yellow
    9. Indole-3-Acetic Acid = Very Dark Yellowish-Brown
    10. Hydroquinone = Black
    11. Sodium Chloride = Reacts with bubbling but no color change
    12. Dimethylglyoxime = Very Pale Yellowish-Brown
    13. para-Dimethylaminobenzaldehyde = Brown
    14. Hexamine = No Reaction

Liebermann's Reagent (Source: Wikipedia)

Dissolve 1 gram sodium or potassium nitrite in 10 mL of 98% H2SO4Hup.org Color change table for Liebermann's Reagent.

  1. The reagent can be tested before analytical use by reacting it with a small sample of two or more of the following:
    1. Acetylsalicylic Acid (Aspirin) = Orangish-brown→ Black
    2. Ascorbic Acid (Vitamin C) = Reacts with bubbling. Pinkish-Brown → Dark Reddish Brown
    3. Granulated Sugar = Reacts with bubbling. Orange → Rapid Brown → Black
    4. Butylated Hydroxytoluene = Very Dark Red
    5. Disodium EDTA = Very Pale Yellow
    6. Triphenylphosphine = Yellow → Light Brown
    7. Tryptophan = Very Dark Orange
    8. Camphor = Reacts with bubbling. Orange 
    9. Indole-3-Acetic Acid = Very Dark Brown
    10. Hydroquinone = Black
    11. Sodium Chloride = Reacts with bubbling. Very pale off-white
    12. Dimethylglyoxime = Yellow → Yellow-Orange
    13. para-Dimethylaminobenzaldehyde = Reacts with bubbling. Light brown with flecks of blue-green (nitrous acid?) → Brown → Dark Brown → Black
    14. examine = Reacts with bubbling. Dark Brown → Rapid Brown → Dark Brown

Froehde's Reagent (Source: Wikipedia)

Dissolve 0.5 grams of Na2MoO4 or molybdic acid in 100 mL 95-98% H2SO4. The mixture is heated to dissolve the salt which can take 2-4 hours to dissolve in cold acid. Hup.org Color change table for Froehde's Reagent.

  1. The reagent can be tested before analytical use by reacting it with a small sample of two or more of the following:
    1. Acetylsalicylic Acid (Aspirin) = Purple
    2. Ascorbic Acid (Vitamin C) = Reddish Brown → Yellow
    3. Granulated Sugar = Greenish-Yellow → Orange → Brown → Black 
    4. Butylated Hydroxytoluene = Purple → Red-Orange
    5. Disodium EDTA = No Reaction → Orange Streaks
    6. Triphenylphosphine = Very Pale Brown
    7. Tryptophan = Brownish Yellow → Mustard Yellow
    8. Camphor = Reacts with bubbling. Reddish Orange
    9. Indole-3-Acetic Acid = Light Orangish Red → Brown
    10. Hydroquinone = Very Dark Purple
    11. Sodium Chloride = Reacts with bubbling but no color change.
    12. Dimethylglyoxime = Peach Orange
    13. para-Dimethylaminobenzaldehyde = Yellow → Rapid Brown → Reddish Brown
    14. Hexamine = No Reaction

Ehrlich's Reagent (Source: Wikipedia and experimental data)

Dissolve 0.5-2 grams of para-dimethylaminobenzaldehyde in 50 mL 95% ethanol and 50 mL concentrated HCl. Use fresh. Hup.org Color change table for Ehrlich's Reagent.

  1. The reagent can be tested before analytical use by reacting it with a small sample of two or more of the following:
    1. Acetylsalicylic Acid (Aspirin) = No Reaction
    2. Ascorbic Acid (Vitamin C) =No Reaction 
    3. Granulated Sugar =No Reaction 
    4. Butylated Hydroxytoluene =No Reaction 
    5. Disodium EDTA =No Reaction 
    6. Triphenylphosphine =No Reaction 
    7. Tryptophan = Purplish Red
    8. Camphor = Reacted with bubbling but no color change. 
    9. Indole-3-Acetic Acid = Purplish Red
    10. Hydroquinone = Slow pinkish-purple
    11. Sodium Chloride = No Reaction
    12. Dimethylglyoxime = No Reaction
    13. Melatonin = Reddish Purple
    14. Hexamine = Greenish Yellow

Improved Ehrlich's Reagent (Source: Wikipedia and experimental data)

Create a 1:1 solution of 5% para-dimethylaminobenzaldehyde in concentrated H3PO4 (specific gravity 1.75) to methanol. Use fresh. Note that the Improved Ehrlich's Reagent will give different color results than the normal Ehrlich's Reagent does. However, the improved reagent has a greater sensitivity. Positive tests tend to be indicated by the formation of a reddish color with purplish hues although this is a general rule of thumb and is not always true.

  1. The reagent can be tested before analytical use by reacting it with a sample of:
    1. Melatonin tablet (slow reddish-violet > violetish-red)
    2. Indole-3-acetic acid (slow orange)
    3. Hydroquinone (no reaction)
    4. Tryptophan (bright yellow > bright orangish-yellow)
    5. Hexamine (light yellow)
    6. Acetylsalicylic acid (no reaction)
    7. Granulated sucrose (no reaction)
    8. Ascorbic acid (no reaction)

Improved Preparation of Brady's Reagent

To a clean dry 125 mL Erlenmeyer flask and magnetic stir bar add 3 grams of 2,4-dinitrophenylhydrazine, 20 mL of H2O, and 70 mL of 95% ethanol. Place the flask in an ice bath. Stir and allow the mixture to cool to 10 oC. With rapid stirring begin the slow addition of 15 mL of H2SO4 trying to avoid boiling. If the temperature exceeds 20 oC halt the addition and allow the mixture to cool back to 10 oC. When the sulfuric acid has been added remove the flask from the ice bath and place it on a hotplate. Stir and warm the flask until the DNPH dissolves or the temperature reaches 60 oC, whichever comes first. Then continue to stir without heating. When the solution has cooled filter through a fritted funnel if necessary. 

A positive test is indicated by the formation of a red, orange, or yellow 2,4-dinitrophenylhydrazone precipitate. If the carbonyl compound is aromatic then the precipitate will be more red and an aliphatic carbonyl compound will tend towards the yellow. The mechanism of action can be found here

Detection of Ionic Species by the Formation of Insoluble Cesium Salts (Source: Wikipedia)
Author's Note: The following equations are non-stoichiometric and only represent the identities of the reagents involved. This is due to their intended use in analysis where the amounts of the reactants are unknown.

Synthesis of 57% Hydriodic Acid (Source: NileRed)

  1. Charge a boiling flask with the KI, the H3PO4, and a few boiling chips (stir bars can be used in lieu of boiling chips). Set up for distillation as normal and attach a hose to the vacuum outlet on the adapter connecting the receiver to the distillation train. To the other end of the hose attach a small funnel and place this funnel upside down in the 10% aqueous NaOH. Commercial phosphoric acid is contaminated with varying amounts of sulfur depending on the grade of the acid. This sulfur is converted into H2S gas during the synthesis and this foul smelling, poisonous gas is removed by reacting it with OH to form S2- and H2O. Also, add some of the NaOH solution to the receiver. A better product can be obtained if one excludes light from the distillation (particularly UV light). Wrapping the distillation apparatus in foil is a simple and effective means of accomplishing this. 
  2. Begin distillation on high heat. H2S, if it is present, will react with the NaOH in the receiver and trap to form a milky precipitate. Continue until the distillate become reddish-brown in color.
  3. When the distillate changes color swap out the receiver with the NaOH/sulfide solution and replace it with an empty, clean receiver flask. Replace the trap with one containing only distilled water. Turn the heat up on the boiling flask to maximum.
  4. Distill the mixture until no more distillate comes over. The trap will capture any HI gas that may have escaped the apparatus. 
  5. When the mixture is fully reacted and distilled combine the liquid in the receiver with the liquid from the trap.
  6. Distill the mixture into an empty receiver. Everything that comes over under 125-127 oC is dilute HI. Once the temperature reaches 125-127 oC remove the boiling flask from the heat and allow it to cool. What remains in the boiling flask is azeotropic 57% hydriodic acid. It is not necessary to distill this although one can do so if one wishes to obtain a clearer, purer product. 

This reaction is not very efficient on this small scale but according to NileRed it's efficiency increases as the batch size increases. 

Synthesis of Sodium Hexanitritocobaltate(III) a.k.a. Sodium Cobaltinitrite (Source: Handbook of Preparative Inorganic Chemistry, Vol. 2, pg. 154)

  1. Dissolve 150 grams of sodium nitrite in 150 mL distilled water and cool the solution to 55 oC. Some sodium nitrite will precipitate.
  2. Add the 50 grams of cobalt nitrate hexahydrate to the solution with stirring. Allow it to stir for a minute or two after the cobalt nitrate hexahydrate appears to have fully dissolved. 
  3. Add the 50 mL of 50% acetic acid in small portions (1-2 mL at a time every several seconds) with stirring.
  4. Run a hose from an air pump down into the mixture and bubble air through it for 30 minutes. This step is best done in a large Erlenmeyer flask tilted at about 45o.
  5. Allow the mixture to stand for two hours.
  6. Filter off the brown precipitate. The filtrate will be dark but must be perfectly transparent.
  7. Add 50 mL of the distilled water heated to 80 oC to the precipitate sludge and stir thoroughly. Filter this as above and combine the two filtrates. Discard the extracted solids.
  8. To the combined filtrates (volume ~300 mL) add 250 mL of 96% ethanol. 
  9. Allow the precipitate to settle for about two hours.
  10. Filter out the precipitate and dry it by vacuum suction for approximately five minutes. 
  11. While continuing suction wash the precipitate four times with 25 mL portions of 96% ethanol followed by two washes with 25 mL portions of diethyl ether. Continue suction for about 5 more minutes. 
  12. Spread out the orange solid on a clean glass plate and break it up into a powder. Allow it to air dry for at least 30 minutes although several hours is better. 
  13. If further purification is needed then dissolve the orange product in a minimal amount of hot water. Using this solution repeat steps 8-12 making reasonable modifications of the amounts as needed.

Sodium Cobaltinitrite will give a precipitate with NH4+1, K+1, Rb+1, Cs+1, and Tl+1 cations. 

Synthesis of Sodium Nitroprusside a.k.a. Sodium Nitrosyl Cyanoferrate (Adapted from Handbook of Preparative Inorganic Chemistry, Vol.2, pgs. 1768-1769)

Rxn 1. K4[Fe(CN)6] + 6HNO3 + Δ → H2[(NO)Fe(CN)5] + 4KNO3 + NH4NO3 + CO2
Rxn 2. H2[(NO)Fe(CN)5] + Na2CO3 → Na2[(NO)Fe(CN)5] + CO2 + H2O

  1. Place the powdered K4[Fe(CN)6] into a 500 mL beaker equipped with a stir bar.  
  2. With stirring slowly add the nitric acid to the beaker. Allow the mixture to stir until the evolution of gasses has ceased and the solids are dissolved. The mixture in the beaker will take on a light blue-green color at this stage. 
  3. Place the beaker in a hot water bath and heat its contents until mixture produces a dark green precipitate when a drop of it is combined with a few drops of aqueous ferrous sulfate solution instead of a dark blue precipitate of Prussian Blue. As the mixture in the beaker is heated it will change from a cyan color to a dark reddish color. However, heating should be continued past this point until the dark green precipitate is obtained from combination with ferrous sulfate. This may take an hour or more and ideally the mixture should be evaporated down to about half it's original volume once this step is completed. 
  4. Cover the beaker and allow the mixture to cool slowly overnight (one source says 1 to 2 days). A very dark liquid contained crystallized contaminated nitrates (usually as black needles or stellated masses) should be obtained.  
  5. Decant the liquid into a clean beaker and discard the nitrate crystals. With stirring neutralize the liquid using dry sodium carbonate. This will take some patience on account of the foaming of the liquid that often occurs. Take care not add an excess of sodium carbonate (a slight excess to ensure complete neutralization is ok but minimize it as much as possible). 
  6. The neutralized reddish solution is heated until it boils at which point it is filtered into a clean beaker equipped with a stir bar.
  7. Place the beaker on a hot plate and heat it with moderate stirring to concentrate the filtrate by evaporation to about half its starting volume. Remove the beaker from the hot plate and allow the liquid to cool to about room temperature. 
  8. Once cooled an equal volume of 95% ethanol is added to the beaker to precipitate most of the remaining potassium nitrate.
  9. The nitrate crystals are removed by filtration and the solution is quickly re-concentrated to remove the ethanol. 
  10. Once the ethanol has been removed the solution that remains will yield dark red crystals on standing. These crystals are suction filtered and washed with a minimal amount of ice water. 
  11. A second crop of crystals may be obtained by reducing the volume of the filtrate and allowing it to stand for a period of time. Addition of a seed crystal from the first batch of crystals may be helpful although it is not difficult to get sodium nitroprusside to crystallize. Attempts to obtain a third crop of crystals have failed due to contamination of the product with nitrates. 

Synthesis of Potassium Bismuthate (Source: Handbook of Preparative Inorganic Chemistry, Vol. 1, pgs. 628-629)

Bi2O3 + 6KOH + 2Br2 → 2KBiO3 + 4KBr + 3H2O

  1. Create a suspension of 165 grams of bismuth oxide in 1.5 liters of 50% KOH.
  2. Heat the suspension until it boils. 
  3. With vigorous stirring add a total of 500 grams of dibromine in small portions of 0.75 to 1.5 mL to the boiling suspension. Large amounts of splattering as well as bromine vapor are created by the chemical and physical reaction of the bromine hitting the boiling suspension so this reaction is best done in a large conical flask. Once all of the dibromine is added a dark violet precipitate results. 
  4. An additional 500 mL of hot 40% KOH is added and the solid material is filtered off after settling. 
  5. The filtered precipitate is washed with 40% KOH and then suspended in 3-5 liters of water and agitated for a few hours. 
  6. Allow the solids to settle and decant the liquid. 
  7. Wash the solids in cold water and filter.
  8. Dry the bright red solid material obtained in a desiccator over 98% H2SO4

Synthesis of Sodium Bismuthate (Source: Handbook of Preparative Inorganic Chemistry, Vol. 1, pgs. 627-628)

Bi2O3 + 6NaOH + 2Br2 → 2NaBiO3 + 4NaBr + 3H2O

  1. Create a suspension of 170 grams of bismuth oxide in 1.5 liters of 40% NaOH. 
  2. Heat the suspension until it boils. 
  3. With vigorous stirring add a total of 300 grams of dibromine in small portions of 0.75 to 1.5 mL to the boiling suspension. Large amounts of splattering as well as bromine vapor are created by the chemical and physical reaction of the bromine hitting the boiling suspension so this reaction is best done in a large conical flask. As soon as the dibromine has begun to be added the solids in the suspension will change from a pale yellow to a mid-toned brown. Once this color change has been fully established by the second or third addition of dibromine the solids retain this color for the rest of the dibromine addition.
  4. Filter off the brown precipitate and wash it with 40% NaOH. 
  5. Suspend the washed solids in 3 liters of water and agitate the suspension until its color changes to a more yellowish-toned color. 
  6. Allow the solids to settle and then add them to 1.5 liters of 53% NaOH. Reflux for 30 minutes with stirring.
  7. Filter off the brown solids, wash them with 50% NaOH, and then add them to 3 liters of water. Briefly agitate the solids in the water.
  8. Stop the agitation and allow the yellowish solids to settle.  
  9. Filter off the solids and wash thoroughly with water. Dry on clay.

Synthesis of Cesium Dichloroiodate(I) (Source: Handbook of Preparative Inorganic Chemistry, 2nd Ed., Vol. 1, pg. 296)

2CsCl + I2 + Cl2  → 2 CsICl2

  1. Prepare a solution of 16.8 grams of cesium chloride in 170 mL water in an Erlenmeyer flask.
  2. Add 2.7 grams of I2 to the solution and bring the solution almost to boiling. While the solution is heating set up a Cl2 gas generator using the reaction between TCCA and concentrated HCl to generate the Cl2. Run a tube from the gas generator to a glass pipette making sure the tube is long enough for the pipette to reach the reaction flask.
  3. Once the reaction mixture is almost boiling put the pipette tip into the reaction flask and bubble chlorine gas into the solution with stirring until all of the iodine dissolves. An excess of Cl2 should be avoided in order to prevent the formation of cesium tetrachloroiodate. The solution should be kept below boiling while the Cl2 is being introduced to prevent vaporization of the I2. However, the temperature must not be allowed to fall too low or the rate of reaction drops off dramatically.
  4. Once all of the I2 reacts remove the Cl2 source from the solution and allow the solution to cool to room temperature. 
  5. Seal the flask and chill it in ice water for about 15 minutes (do not allow the solution to freeze). 
  6. Remove the flask from the ice water and filter out the first crop of crystals. This first crop of crystals tends to be a mass of largely white crystals mixed with small orange to yellow-orange crystals. It is obviously two different substances that have precipitated together but the exact identity of the white component (which makes up the bulk of this first crystallization) is unknown. It can be stored normally and saved for future experimentation or it can be thermally decomposed to recycle any iodine and cesium chloride it contains.
  7. Transfer the filtrate to a clean beaker and boil it down to about 75% it's starting volume.
  8. Remove the flask from the heat and as before allow it to cool to room temperature before sealing the beaker and putting it in ice water for about an hour. Again take care not to let the solution freeze.
  9. Remove the flask from the ice water and filter out the second crop of crystals. This second crop of crystals tends to come in the form of a jumbled mass of very tiny orangish-yellow needles. All hints of the white solid from the first crystallization should be gone and this step yields the first batch of pure cesium dichloroiodate product.
  10. Transfer the filtrate to a clean beaker and boil it down to about 20-25% it's starting volume. Once complete repeat step 8. 
  11. Remove the flask from the ice water and filter out the third crop of crystals. This third crop tends to come in the form of spectacular bundles of orangish yellow needles that can be as long as the beaker is wide (see the picture below). 
  12. Filter off the crystals and combine these with the crystals obtained in step 9. If the filtrate from step 11 is of sufficient volume a fourth run of crystallization can be carried out in a manner similar to the other three. However, only a small amount of product would be obtained at best and it may be more desirable to simply combine whatever liquid remains with the solids from the first crystallization in step 6 for recycling of iodine and cesium chloride. 
  13. The combined crystals from steps 9 and 11 are generally of good purity and can normally be dried in a desiccator and used as is. However, if further purification of the CsICl2 product is deemed necessary it can be recrystallized from a small amount of hot HCl (1:1) and washing with a small amount of cold HCl. 

Orangish-yellow crystals which melt at 238 oC in a sealed tube, evolving labile halogen at 290 oC. CsICl2 is much more stable than KICl2. Cesium dichloroiodate decomposes according to the equation: CsICl2 → CsCl + ICl whereas cesium tetrachloroiodate decomposes according to the equation: CsICl2 → CsCl + ICl3. The characteristic bundles of needles obtained from the third crystallization step are pictured below. For a sense of scale these crystals were photographed in a 100 mL beaker. It has been suggested that during this run the product was over-chlorinated and these crystals are actually CsICl4.

Simon's Reagent (Source: Wikipedia)

Simon's Reagent is an analytical reagent used to detect secondary amines. The reagent is made up as two solutions, A and B, each of which is added to the sample being tested. Solution A: Dissolve 1 g of sodium nitroprusside in 50 mL of distilled water and add 2 mL of acetaldehyde to the solution with thorough mixing. Solution B: 2% Na2CO3 in distilled water. Procedure: Add 1 volume of solution A to the sample followed by 2 volumes of solution B. 

The amine and acetaldehyde produce the enamine, which subsequently reacts with sodium nitroprusside to the imine. Finally, the iminium salt is hydrolysed to the bright blue Simon-Awe complex. 

Robadope Reagent  (Source: Wikipedia)

The formulation of Simon's Reagent can be altered such that it gives a positive test with primary amines instead of secondary amines. The reagent is made up as two solutions, A and B, each of which is added to the sample being tested. Solution A: Dissolve 1 g of sodium nitroprusside in 50 mL of distilled H2O and add 2 mL of acetone to the solution. Solution B: 2% Na2CO3 in distilled water. Procedure: Add 1 volume of solution A to the sample followed by 2 volumes of solution B. 

The amine and acetaldehyde produce the enamine, which subsequently reacts with sodium nitroprusside to the imine. Finally, the iminium salt is hydrolysed to the bright blue Simon-Awe complex. 

Zwikker's Reagent  (Source: Wikipedia)

The Zwikker Reagent is used as a simple spot test to presumptively identify barbiturates. It is composed of a mixture of two solutions. Part A is 0.5 g of CuSO4 in 100 ml of distilled water. Part B consists of 5% pyridine (v/v) in chloroform. One drop of each is added to the substance to be tested and any change in colour is observed.

The test's lacks specificity and has a tendency to produce false positives. However, it is still of use as a TLC stain. The test turns phenobarbital, pentobarbital, and secobarbital light purple while tea and tobacco turn yellow-green. 

Dille–Koppanyi Reagent (Source: Wikipedia)

The Dille–Koppanyi Reagent is used as a simple spot-test to presumptively identify barbiturates. It is composed of a mixture of two solutions. Part A is 0.1 g of Co(CH3COO)2•2H2O dissolved in 100 ml of methanol mixed with 0.2 ml of glacial acetic acid. Part B made up of is 5% isopropylamine (v/v) in methanol. Two drops of A are dropped onto the substance followed by one drop of B and any change in colour is observed.

The test turns phenobarbital, pentobarbital, amobarbital and secobarbital light purple by complexation of cobalt with the barbiturate nitrogens.

Synthesis of Potassium Metaperiodate (Source: Rhodanide)

Rxn 1. 2KIO3 + 2K2S2O8 + 6KOH → K4I2O9 + 4K2SO4 + 3H2O
Rxn 2. K4I2O9 + 2HNO3 → 2KIO4 + 2KNO3 + H2O

  1. Add 50 mL of distilled water to a 500 mL beaker followed by a stir bar and the potassium iodate (the KIO3 will likely not dissolve which is alright) 
  2. With stirring add 15 grams of KOH to the beaker and then heat the mixture until boiling.
  3. Add 23 grams of potassium persulfate to the mixture in small portions. A color change to yellow or tan may occur which is normal. 
  4. Next add 15 grams of KOH to the mixture slowly and in small portions. 
  5. Heat the mixture for another  (30 minutes to ensure the reaction is complete. While this is happening heat 150 mL distilled water to boiling. 
  6. Add the boiling water to the mixture to dissolve the potassium sulfate produced by the reaction. 
  7. Next cool the solution in a room temperature water bath. If it is too cold potassium sulfate will crystallize. 
  8. Acidify the solution by addition of small portions 40% nitric acid with stirring. It should still be in the water bath while this is carried out. This step will convert the paraperiodate present into metaperiodate. 
  9. When the pH of the mixture becomes acidic the color will change from a yellowish tan color to white. However, this color change cannot be solely relied on and the pH of the solution should be independently confirmed before proceeding. A few extra milliliters of 40% nitric acid are added to ensure full conversion of paraperiodate.
  10. Add ice to the water bath and cool the mixture to ensure full precipitation of potassium metaperiodate.
  11. Vacuum filter off the solids. Wash the solid cake with a small amount of cold water and then vacuum filter off this as well.
  12. Remove the potassium metaperiodate and spread it out to dry. KIO4 can be recrystallized from boiling water. 

Synthesis of Anthranilic Acid Using Hypochlorite (Source: Prepchem.com, ChemPlayer)

  1. 40 grams of sodium hydroxide is dissolved into 140 mL of distilled water and the solution is chilled on ice to 10 oC. While this is happening 200 grams of 5% sodium hypochlorite is chilled on ice to between 5 and 10 oC. 
  2. 20 grams of phthalimide is added to the chilled sodium hydroxide solution with vigorous stirring. The phthalimide will take several minutes to dissolve even with vigorous stirring and the temperature will increase as it does so by about 10-15 oC.  A small amount of water (up to about 100 mL) can be added if necessary to create a clear solution though it should be kept to a minimum.
  3. Once the phthalimide is dissolved the solution is chilled back to 10 oC.
  4. The chilled 200 grams of 5% sodium hypochlorite solution are added to the phthalimide solution with stirring and the resulting solution is allowed to stir for 15 minutes. 
  5. The solution is then heated to 80 oC after which it is removed from the heat, allowed to cool, and then chilled back down to ~10 oC. 
  6. The solution is then neutralized exactly with concentrated hydrochloric acid or sulfuric acid. The solution will go from being very slightly yellow tinted before the neutralization to a somewhat darker brown color after the neutralization. Since the neutralization must be exact it may be helpful to set aside a small amount of the alkaline solution (perhaps 20 to 40 mL) before the neutralization to use if exactly neutral is missed and the final solution is slightly acidic. This can be neutralized on its own (recommended) or added to the main solution to be neutralized there. 
  7. Once the solution is neutralized ~50-60 mL of glacial acetic acid is added with stirring to precipitate the anthranilic acid. This precipitation can take a few minutes before it begins and then will continue for several minutes. Bubbling will occur and a moderate amount of foam will be produced. Do not discard the foam as a large amount of the very light anthranilic acid product will be trapped within it. 
  8. The anthranilic acid is vacuum filtered from the solution. It is washed with ~100 mL of ice water. The crude product has the appearance of a light, granulated brown sugar although it is much lighter in weight. This crude anthranilic acid is set aside for further purification. 
  9. The filtrate is combined with 100 mL of a saturated solution of copper sulfate to precipitate remaining anthranilic acid as cupric anthranilate which is a heavy emerald green solid. This is filtered out and the dark green filtrate is discarded.
  10. The cupric anthranilate is suspended is water with stirring and hydrogen sulfide gas is bubbled through the suspension. This will displace the anthranilic acid from the copper(II) ions forming copper sulfide which precipitates as a heavy black solid.  
  11. The copper sulfide is filtered off and discarded. The filtrate is evaporated down on a hot water bath in order to retrieve the remaining crude anthranilic acid.
  12. The crude anthranilic acid from steps 8 and 11 are combined and recrystallized from a minimal amount of boiling water. The final product is an off white to light brown color and the melting point of anthranilic acid is 146-148 oC.

Bisulfite Reagent for the Precipitation of Aldehydes

"This reagent is prepared by treating a saturated aqueous solution of sodium bisulphite with 70% of its volume of rectified (or methylated) spirit, and then adding just sufficient water to produce a clear solution. The bisulphite solution obtained by passing sulfur dioxide into sodium carbonate solution is not recommended since the resulting yellow solution contains free sulphurous acid which dissolves some bisulphite compounds." A Text-Book of Practical Organic Chemistry Including Qualitative Organic Analysis, 3rd Edition, by Arthur I. Vogel. Longman Group Limited, London, 1974, page 332. (ISBN: 0582442451)

Preparation of Copper Chromite Catalyst (Source: Doug's Lab)

Rxn 1. (NH4)2Cr2O7 + 2NH4OH → 2(NH4)2CrO4 + H2O
Rxn 2. 2(NH4)2CrO4 + CuSO4 → Cu(NH4)2(CrO4)2 + 
Rxn 3. Cu(NH4)2(CrO4)2 → D → CrCuO3 + Cr2Cu2O5 + Cr2CuO4•CuO

  1. In separate beakers dissolve the ammonium dichromate in 33 mL of distilled water and the copper(II) sulfate pentahydrate in 60 mL of hot water. 
  2. Slowly add the 10% aqueous ammonia to the beaker containing the ammonium dichromate solution with stirring in order to convert it into an ammonium chromate solution. 
  3. Slowly add the solution of of ammonium chromate to the copper(II) sulfate solution with rapid stirring. The brick red copper ammonium chromate will precipitate in an exothermic reaction. Allow the mixture to stir for about 5 minutes to ensure that the reaction is complete. 
  4. Filter out the precipitate using vacuum filtration. This filtration can be difficult and it is not necessary to filter to complete dryness.
  5. Transfer the copper ammonium chromate paste to an evaporating dish and mostly dry it out over a boiling water bath. 
  6. Crush the mostly dry copper ammonium chromate to a fine powder. Return to the evaporating dish to complete the drying process.
  7. Transfer the dry copper ammonium chromate into a crucible and heat the powder over an open flame. Heat gently for about 10 minutes thereafter increasing in intensity until the temperature is approximately 400 oC. Maintain this temperature for about 10 minutes after which the powder should have turned completely black. 
  8. Once the catalyst is cooled add it to a beaker containing 130 mLs of 10% acetic acid solution with stirring. Allow to stir for about 10 minutes. 
  9. Decant the supernatant and then wash with another 130 mLs of 10% acetic acid for about 10 minutes. 
  10. Allow the solid to settle for about 10 minutes. 
  11. Separate the copper chromite catalyst from the liquid by vacuum filtration rinsing all the solid from the beaker with distilled water. 
  12. Dry the powder in an evaporating dish to obtain the dry catalyst. Copper chromite is stable with regards to moisture and air. 

UNODC Modified Ehrlich's Reagent (Source: UNODC Bulletin: Analytical Separations of Mixtures of Hallucinogenic Drugs)

Create a solution of 125 mg p-dimethylaminobenzaldehyde in 100 mL 1:1 H2SO4 to which 2 drops of 10% ferric chloride have been added. 

UNODC Potassium Iodoplatinate Reagent (Source: UNODC Bulletin: Analytical Separations of Mixtures of Hallucinogenic Drugs)

Create a solution of 3 mL of 10% platinum chloride solution mixed with 97 mL of water to which is added 100 mL of 6% aqueous potassium iodide solution

Synthesis of Antimony(III) Iodide (Source: Handbook of Preparative Inorganic Chemistry, 2nd Ed., Vol. 1, pg. 614, Personal Experimentation)

  1. A solution of 14 grams of iodine in 300 mL of toluene is refluxed with 7 grams of antimony until the iodine color disappears. This generally takes 3 to 4 hours. The use of rapid stirring that keeps the particles of antimony moving helps the reaction proceed more quickly.
    1. Note that antimony is present in excess so some will be left over when the reaction is complete. 
  2. The solution is filtered from the unconverted antimony and allowed to crystallize in a sealed flask immersed in a cold water bath. Do not allow the antimony(III) iodide to come into contact with water or excessive amounts of water vapor or it will react to form antimony oxyiodide. 
  3. The crystals are scraped from the sides and bottom of the flask and then recovered by filtration.
  4. The crystals can be dried in a vacuum desiccator at 40 oC or alternatively they can be rinsed 3-4 times with small portions of chloroform (cannot substitute dichloromethane since SbI3 is much more soluble in DCM than CHCl3 or CCl4) and then quickly dried under a stream of hot air while being stirred. 
  5. Store the antimony(III) iodide in an airtight bottle that will protect it from moisture and humidity. 

Synthesis of Rubidium or Cesium Dichromate from Rubidium or Cesium Chloride

Rxn 1. (NH4)2Cr2O7 + 2RbCl → Rb2Cr2O7 + 2NH4Cl 

  1. In separate beakers dissolve the rubidium/cesium chloride and the ammonium dichromate in a minimal amount of hot water. 
  2. Combine the solutions with stirring. Crystals of rubidium or cesium dichromate precipitate out almost immediately.
  3. Allow the solution to cool to precipitate out as much of the dichromate as possible. 

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