Sciencemadness Discussion Board - Copper(II) Aspirinate Synthesis

Copper(II) Aspirinate Synthesis

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bfesser - 27-9-2013 at 05:31

Neat. I love seeing photos of copper complexes. What method(s) did you use to verify the identity of your product?

Oscilllator - 27-9-2013 at 20:47

Well Apart from the that its a complex, I don't actually know anything about it. All I can say is that it dissolves in a solution of sodium bicarbonate, and when enough HCl is added to this mixture the deep green colour disappears and a white precipitate (presumably salicylic acid) can be seen floating about.

sargent1015 - 30-9-2013 at 20:58

Quote: Originally posted by Oscilllator

I also attempted to prepare a nickel analogue, however is seemed that only nickel carbonate formed

Did you try dissolving the acetylsalicylic acid in bicarb before adding the metal? Also, with slight excess of the acetyl salicylic acid?

News on my synthesis:
I obtained... a deep blue oil, interestingly enough. I wish we still had our IR setup in my lab, I could check if it was actually coordinated :/

Semmelweis - 16-10-2013 at 12:16

I guess a more direct approach would be to react the ASA with CuOH.
It's too weak a base to cause hydrolysis.
I make my CuOH from electrolysis. Fun compound to mess with, one easily gets copper chloride to show it's very exothermic reaction with Al.
I think I will be trying this as soon as I get more Aspirin.

bfesser - 16-10-2013 at 13:46

Quote: Originally posted by Semmelweis

I guess a more direct approach would be to react the ASA with CuOH.

Sometimes I wonder why I even bother.

ASA is quite insoluble in H2O at 20°C. If you heat to increase solubility, it will decompose. Also, your "CuOH" is not. It's a complicated aqueous complex precipitated mess. I think you'll be hard-pressed to get them to react, and even if you do, you'll have to wash excess ASA out of your product with an organic solvent and the leftover [CuOH] with a weak acid, such as dil. ethanoic acid (use of a strong acid would turn your product back to ASA and a Cu2+ salt). In summary, your proposed method would be just as much work, and likely have lower yields and poor purity (inclusion of [CuOH] into precipitate during crystal growth).

A tip: I've found that (in my experience) it's generally a bad plan to react an insoluble species with a solution when you're expected product is itself insoluble—it's generally slower and affords lower yields of a lower purity product than other means.

[edit] P.S. I see that you're from Brazil; any chance you could U2U me with a city name? I'm looking for someone to collect and ship a mineral specimen.

[Edited on 16.10.13 by bfesser]

Semmelweis - 16-10-2013 at 15:18

Well, I thought it could be done on ethanol, evaporate, and wash with the weak acid as you said. In fact, I have just done a test with 1 crushed aspirin tablet, some ethanol and a little copper hydroxide, everything eyeballed in a test tube, and after shaking a lot got a color surprisingly near that of the photo. I know, however, that for this to actually work would be against all odds.

Boffis - 21-11-2013 at 17:12

I recently repeated my experiment with nickel carbonate but this time I used salicylic acid instead of aspirin. The nickel carbonate dissolves in the suspension of salicylic acid producing a pale greenish liquid that would no crystallise on cooling, on evaporation (a pale green glassy residue was obtained) or on treatment with excess alcohol. I suspended 0.5g of salicylic acid in 10ml of water and heated almost to boiling and added basic nickel carbonate until no further effervescence occurred, filter it while hot through a small hirsh funnel to remove the excess carbonate and cooled it slowly in an open 25cc beaker. By the following morning almost half the liquid had evaporated but no crystals had formed. Evaporation to dryness in a shallow porcelain basin left a glassy residue which dissolved again rapidly in a few cc of water and would not crystallise even when 5ml of ethanol (95%) were added. I conclude that the salicylate complex of Ni2+ is very soluble. It also appears identical to the product that I had obtained from aspirin, which tend to confirm bfessor's contention that the boiling would have hydrolysed the aspirin.

bfesser - 21-11-2013 at 17:36

Interesting. Thanks for sharing your experimental results.

AlChemicalLife - 7-12-2013 at 10:36

I was thinking of posting this in a new thread but, Since there is already a thread on this ,i didn't want to annoy people with making another thread of the almost exact same thing , the only thing different is this starts with copper metal. But if you guys would like to take a look that would be great, My synthesis of this compound was using Anon's video on making this Copper Aspirinate, and making it from scratch.

So A few days ago i was asked to write up an experiment which started out with the metal and ended up as a useful compound that could be used as a pharmaceutical or in a way that could help life. So i thought and thought, and experimented with different things , searching YouTube and Google. And i came across a few that i liked but the one that caught my eye was copper aspirinate
, A Copper compound that is used as a treatment for rheumatoid arthritis interested me, than i realized , How am i going to go from copper to the Compound. I kept searching, and found a synthesis that i liked, that used compound's i know how to make from copper , and i went the easiest wrought to do the following Experiment and this experiment is in the processes of being put into my website , but there are a few minor things i will change.

"From Copper metal to Pharmaceutical"
In this experiment I will start with Plain copper metal(And a Few house hold materials) , and end up with Copper aspirinate.
First we need to make a soluble copper compound that will react with Sodium Bicarbonate, usaly we could use copper sulfate, but lets say you dont have that available,Are you out of luck?
Well , luckily for you your not out of luck, We can make another soluble copper compound that will react with Sodium bicarbonate to form Copper carbonate, We will make Copper acetate.Than we will react the copper acetate with sodium carbonate to form copper carbonate , Than we will isolate ASA (Acetylsalicylic acid) From aspirin, and then react the Acetylsalicylic acid with the copper carbonate to form Copper aspirinate

Making the copper acetate: Making this compound could not be easier, you will want to make up a solution with vinegar and hydrogen peroxide, you will want to use double the amount of vinegar that use use from hydrogen peroxide ( Say you use 30mls of hydrogen peroxide , Thank you will want to use 60mls of Vinegar ). After you make this solution you will want to drop in some copper ( About 10grams should be plenty, but if you run out of copper add more ) Now heat the solution To a slight boil and add the copper , you will notice it bubble.( NOTE: you can also just add the copper without heating , this will take longer, but is safer ) As its bubbling you will notice the color change from clear to blue(This is NORMAL) ,the reaction is complete when the solution is a deep blue or when you copper metal stops reacting . The Equation is here - CH3COOH+H2O2+Cu =
Cu(CH3COO)2+H2O+O2.
Now that you have the solution we will move onto making the Copper Carbonate

Making the Copper Carbonate: Making the copper carbonate is easier than make the Copper Acetate. What you want to do now is make up a Saturated solution of Sodium bicarbonate, After you have a solution of Sodium Bicarbonate , take that solution and add it to the copper acetate solution, (You will notice a green/blue precipitate This is our copper carbonate ) Keep adding the solution till no more precipitates out of solution. After you have all of it precipitated out of solution , filter and wash with copious amounts of cold water to remove trace amounts of Bicarbonate that may be in your product. Set the copper carbonate out to dry. While we wait for this to dry we now can make our Acetylsalicylic acid.

Making the Acetylsalicylic acid from aspirin : Making Acetylsalicylic acid, isn't to difficult , its actually pretty fun , So lets get started .
You will first want to start out by placing some water into a freezer to cool it down to a low temp , just above freezing.
As we are waiting for the water to cool, We can prepare our solution we will pour into the cool water.
Start by measuring about 1ml of Isopropyl alcohol per aspirin tablet used, in this experiment i used about 25 Tablets , so i will measure out 25ml's of Isopropyl Alcohol.
Then add the Tablet, and the Isopropyl alcohol to a beaker and lightly heat do dissolve all the aspirin (DO NOT BOIL THE ALCOHOL!, Boiling it may cause the ASA to Turn in to Salicylic acid ) After all the aspirin has dissolved,There may still be a cloudiness do to binders N' such that are not soluble in the IPA.
Take this solution a filter it to make sure no binders are left, Then take you water out of the freezer, now take your solution with the ASA in it and add it to the cold water.
You should see a nice fluffy white precipitate come out of solution, This is you ASA and you can take this and filter this off, while filtering wash with copious amounts of cold water and ice cold Isopropyl alcohol.After This is done you can now dry it or recrystallize it(this isn't necessary, but will improve your product to just make sure no binders are left) . To recrystallize just add just enough Hot Isopropyl alcohol to dissolve all the product , Then set that out to recrystallize, putting a continues air stream helps yield. Dry this and we will move on to the next and final step to our tour of making a pharmaceutical.

Making The Copper Aspirinate: YAY !!FINALLY!! You have survived this long and now its time to make the final product!!, this, like all the other steps isn't to difficult.
First weigh out 9 grams of Acetylsalicylic acid and 3 grams of Copper(II)carbonate.
add the 9 grams of Acetylsalicylic acid to 75ml's of distilled water, Bring this water close to boiling. Now With Lots of stirring (Preferable with a hotplate stirrer ) slowly add the copper carbonate, adding to much at once will result in the reaction overflowing onto the hotplate. You will note a color change from the greenish blue copper carbonate to the Blue Copper Aspirinate. After all the carbonate has been added keep stirring and gentle heating for about 5-10 minutes then shut off the stirring and heat and let the Copper Aspirinate settle. after its settled , if you observe bubbling, turn back on stirring and gentle heating,this means the carbonate and Acetylsalicylic acid haven't fully reacted.
When your ready to proceed, filter the product ( Using a vacuum is highly rec emended ) At this stage your product is impure with left over Un-Reacted Acetylsalicylic acid, add the product to a beaker , and add approximately 100ml's and stir to dissolve impurity's. Now re filter you product, it should look MUCH cleaner , if there are anymore impurity's try and get them out by picking them out . Now Dry your product and your finished!! After this Long experiment you deserve a coke or Pepsi (Or a beer for you fellow beer drinkers) to drink , and a pat on the back, you have made a pharmaceutical from copper metal,aspirin , and a few other house hold products!

any questions of this are welcome !! Hope you enjoyed it.

bfesser - 7-12-2013 at 18:39

Why do people keep insisting on reacting an insoluble copper compound with acetylsalicylic acid? Please read everything written above to understand why this is a bad route. By the way, most of the videos I've seen for copper(II) aspirinate on YouTube have been just plain awful. You should try doing a little proper research before blindly following anything you see on YouTube. You'll find that many of the videos, if not all, were made after this topic was opened. Sadly, none of the authors seem to have read through this or understand what they're actually doing.

[edit] If you put this on your website, a link to Science Madness would be appreciated.

[Edited on 8.12.13 by bfesser]

AlChemicalLife - 8-12-2013 at 08:43

I just wrote that experiment up for fun, weather or not it was effective or efficient wasn't on my mind. And when i get done with proofing and taking picture ill post it on my website and put a link to this thread , and it will be noted this is not the most efficient or effective way to make it, but it is fun and i enjoyed it

sargent1015 - 28-12-2013 at 11:22

First off, feels good to be done with the semester and back on ScienceMadness! Back to my aspirinate fun!

Second,

Quote: Originally posted by AlChemicalLife

Bring this water close to boiling. Now With Lots of stirring (Preferable with a hotplate stirrer ) slowly add the copper carbonate, adding to much at once will result in the reaction overflowing onto the hotplate...

If you heat it, you run the risk of decomposition, likely forming some salicylic acid. Why not skip the carbonate synthesis step and make it directly from copper acetate??

bfesser - 4-1-2014 at 12:05

Just found this gem:

Hybrid (Electrochemical-Chemical) Single Crystal Synthesis of Copper Aspirinate Starting from an Aspirin Tablet: an Undergraduate Bioinorganic Experiment.
A. Pérez-Benítez, M.A. Méndez-Rojas, S. Bernès, E. González-Vergara
Chemical Education Journal (CEJ), Vol. 11, No. 2 /Registration No. 11-8 /Received January 23, 2008
<a href="http://chem.sci.utsunomiya-u.ac.jp/v11n2/PerezBenitez/PEREZ_BODY.html" target="_blank">http://chem.sci.utsunomiya-u.ac.jp/v11n2/PerezBenitez/PEREZ_BODY.html</a> <img src="../scipics/_ext.png" />

sargent1015 - 22-1-2014 at 13:09

That is awesome! ! ! Anyone try it yet?

bfesser - 22-1-2014 at 15:31

I replicated the experiment shortly after that post, substituting 0.9 mm pencil lead, and got very poor results. I did get some product, but the crystals are much smaller than claimed by the original authors—I didn't bother to recover them.

TheChemiKid - 4-2-2014 at 15:04

Here is a video I made on the synthesis of copper aspirinate. Hope you enjoy it.

DraconicAcid - 4-2-2014 at 15:25

Nice video, but it's incorrect to refer to the copper aspirinate as a ligand. The aspirinate ion acts as a ligand to the copper, but the whole thing isn't a ligand.

bfesser - 4-2-2014 at 15:37

Nice work, kid. You've made the only decent video I've seen of copper(II) aspirinate, so far! I'd recommend correcting the narration to refer to it as a "copper chelate" (<a href="https://ssl.gstatic.com/dictionary/static/sounds/de/0/chelate.mp3" target="_blank">/ˈkēˌlāt/</a> <img src="../scipics/_ext.png" />

or "copper coordination complex" (<a href="https://ssl.gstatic.com/dictionary/static/sounds/de/0/coordination.mp3" target="_blank">/kōˌôrdnˈāSHən/</a> <img src="../scipics/_ext.png" />

, and putting a visual in the black screen part near the end.

Copper imidazole complex

sargent1015 - 6-2-2014 at 19:43

Nice video man! Since we are giving pointers (and this is what I tell my students), you should give molar quantities rather than grams of this plus grams of that. It is much more scientific and less "cooking" style.

Anyways, back to the fun of copper complexes since I will have free time this weekend!
First things first, my imidazole complex of copper seemed to work (seemed since I have a waxy, dark blue product now, and no access to an FTIR). I guess if you guys want to try and confirm this little experiment I ran, I'll write up a little blurb. I don't have any idea for purifying so far, maybe you guys will have ideas.

0.232 g (3.4 mmol) of imidazole was dissolved in ~100% ethanol. To this solution, 0.72 g (0.85 mmol) of copper (II) aspirinate was added. The cloudy blue solution was stirred for an hour.

And this is where my notes went to crap and it has been awhile since I actually performed the experiment, so I am not positive if I did anything after that step. All I know is that I let it air dry for several days and got a waxy, blue solid.
Ideas/comments/etc. are encouraged here. I am in the process of remaking some copper aspirinate to redo it.

Copper (II) Benzoate Synthesis

sargent1015 - 6-2-2014 at 20:51

Also, I noticed that no one has a write up for copper (II) benzoate. I like my method which uses both organic and inorganic routes to the product. Not really scientific writing, but eh, I've been grading papers all day.

1) Benzoic acid from toluene. I love this reaction way more than I should, plus it is a great beginner organic reaction. No write up here (Someone really should put one in the "Pre-Pub" section though), just a nice video of the synthesis: benzoic acid

2) Next, we can take our fresh benzoic acid and deprotonate it with sodium hydroxide in water. The important part for this step is to make sure that the benzoic acid is in excess and can be filtered away before the next step. This ensures that there is no leftover sodium hydroxide in the solution, which will inadvertently react with copper sulfate.

3) Lastly, to your filtrate from step 2, add half an equivalence of copper (II) sulfate pentahydrate. Immediately, the product, copper (II) benzoate, will crash out of the solution and can be obtained by filtration and rinsed thoroughly with water. This yields fine, pale blue crystals.

Simple synthesis, really, and emphasizes a lot of good chemistry and techniques.

DraconicAcid - 6-2-2014 at 21:06

I suspect your structure for copper(II) benzoate is inaccurate. Isn't it similar to the acetate, actually being dimeric?

sargent1015 - 6-2-2014 at 21:10

Didn't think about it, but here is the wiki answer:
http://en.wikipedia.org/wiki/Copper_benzoate

"Copper(II) benzoates exists in at least two structural forms, depending on the degree of hydration."

HeYBrO - 7-2-2014 at 03:50

Quote: Originally posted by sargent1015

2) Next, we can take our fresh benzoic acid and deprotonate it with sodium hydroxide in water.

Nice route but, the deprotination seems unnecessary IMO, as you form potassium benzoate in the first step, which then you acidify and then deprotinate... The solubility between the two is negliable too (sodium benzoate 62.9 g/100 ml water, potassium benzoate 65 g/100 mL- wiki) I am I missing something or..?

Nicodem - 7-2-2014 at 04:45

Quote: Originally posted by sargent1015

Didn't think about it, but here is the wiki answer:
http://en.wikipedia.org/wiki/Copper_benzoate

"Copper(II) benzoates exists in at least two structural forms, depending on the degree of hydration."

The structure depicted on the Wikipedia page is most certainly completely wrong. Interestingly, the wiki article itself claims a different structure in its Structure section. Anyway, if you follow the references it gives, you can see that the various copper(II) benzoates all are coordination compounds, just like the copper carboxylates generally are. The benzoate ligand acts as bridging ligands between two copper atoms. See Acta Cryst. 1992, B48, 253-261 (DOI:10.1107/S0108768191012697, attached) for the structure of some Cu₂(BzO)₄L₂ compounds.
I don't have the access to DOI: 10.1143/JPSJ.18.117 where the structure of copper benzoate trihydrate is reported, but then again neither do you seem to know which copper(II) benzoate did you obtain.

Attachment: ActCryst_B48_253_261.pdf (278kB)
This file has been downloaded 679 times

sargent1015 - 7-2-2014 at 10:08

Quote: Originally posted by HeYBrO

I should have clarified, while it is cool and dandy to make copper benzoate, I do not need a huge surplus of it. So I made the benzoic acid, isolated it, and used only the amount I wanted for the copper benzoate synthesis.

Thanks Nicodem for the correct structure, it's been quite some time since I've played with inorganic. Just goes to show you how "reliable" wiki is.

Quote:

but then again neither do you seem to know which copper(II) benzoate did you obtain.

Not even the slightest clue

-Sarge

HeYBrO - 7-2-2014 at 15:32

Quote: Originally posted by sargent1015

I see, very nice. Did you use hardware store toluene? I want to do this but I don't really want thiophene containing wastes associated with the purification, as i don't know how to destroy it/ dispose of it. Any ideas?

sargent1015 - 7-2-2014 at 19:22

Actually, yes! It was hardware store toluene, I even took a 400 MHz NMR after the synthesis and it was remarkably pure.

sargent1015 - 24-2-2014 at 22:19

Also, toluene can be cleaned up with a couple sulfuric acid washes (Enter Vogel reference here). Did you try the synthesis yet?

Well, I also have some pictures since everyone loves that.

First, this is the aspirinate/imidazole complex (Maybe?). It is very waxy and a deep, dark blue.

Second, a little copper benzoate!

DraconicAcid - 17-11-2014 at 22:39

In this thread: http://www.sciencemadness.org/talk/viewthread.php?tid=26316 a paper is given on the synthesis of aspirinates of copper, nickel, cobalt, and zinc (Journal of Enzyme Inhibition and Medicinal Chemistry, 2002, Vol 17 (2), p 87-91). It's another lousy paper, riddled with errors.

First of all, it gives exactly one synthesis, that of a cobalt aspirinate, and declares that the other compounds were made by the same procedure, only with different molar ratios of the reactants. Insufficient experimental data!

Second, the formulation for the compounds are given as ML₂, MCl₂L₂, and M₂L₄ (where L = aspirinate or acetylsalicylate). Since these are divalent metals, the formulation with two chlorides and two aspirinate anions is clearly wrong (that would require a tetravalent metal).

Thirdly, how on earth is one supposed to get one of these three complexes through "different molar ratios of the reactants", when there are two aspirinate anions for each metal in every single proposed formulation?

sargent1015 - 22-3-2015 at 07:18

Well hi there guys! I have not been working on anything for this forum in quite some time since I moved across the country and started grad school in organic chemistry. Not only did I not have the space to haul all of my equipment, but my time outside of lab anyways is quite limited, so I will live vicariously through you guys!

Has anyone done asprinate work in awhile? Maybe I can revitalize this thread and get someone to pick up where I left off

Anyways, hope everyone is doing well

Kitsune1 - 22-3-2015 at 12:47

I have around 10g of ASA in my lab ready to extract when I find time so I would be interested in trying acetylsalicylate metal complexes; after I finish my current project, Nd extraction with organic ligands.

I do have to say my preferred method of ASA separation is a bit different; after dissolving the tablets in an appropriate volume of warm ethanol, filter and add the same quantity of distilled water (the ASA crystals precipitate which is really pretty), let the crystals settle. Decant into a filter, wash with cool water and then leave to dry (don't evaporate with heat, this ends with thermal decomposition).

A benefit to this is that the ethanol can then be distilled and used again and all named binders (in my source at least) are insoluble in ethanol, the efficiency is also very high due to the insolubility in low concentration ethanol.

aaronperezb - 22-4-2015 at 10:52

Quote: Originally posted by bfesser

I replicated the experiment shortly after that post, substituting 0.9 mm pencil lead, and got very poor results. I did get some product, but the crystals are much smaller than claimed by the original authors—I didn't bother to recover them.

aaronperezb - 22-4-2015 at 11:10

Please use drinking water to improve your results and you can optionally replace the pencil lead by a copper wire as cathode. Interrupt the power supply when a black powder (CuO) begins to appear but let the chemical reaction finish, this means the blue powder (Cu(OH)2) disappears.

Muhammad - 22-2-2017 at 00:49

So I followed the steps for the synth of copper acetylsalicylate. I didn't get an immediate formation of precipitate, just a formation of a greenish blue solution. I checked an hour later and crystals were forming on the sides and the base. The crystals are insoluble in water, have and greenish bluish hue and And slightly remind me of tiny acetate crystals. Have I done it right?

Copper (II) acetylsalicylate precipitation

Muhammad - 10-9-2017 at 00:39

I did a precipitation with copper II sulfate and sodium acetylsalicylate and the product did not precipitate immediately. instead it crystallized on the walls of the container over some time. Was this precipitation? I do not understand what happened.

VSEPR_VOID - 10-9-2017 at 11:38

Try posting your entire procedure, sources, pictures, and how your prepared the reagents in your reactions. Your post is not detailed enough. IF you can read it in 30 seconds its most likely not worth posting.

DraconicAcid - 28-9-2017 at 11:53

So did anyone manage to get an aspirinate other than that of copper? We've got cobalt(III) and iron(III) mentioned in the thread, but were these followed up to be sure that they were actually the desired compounds?

DraconicAcid - 29-9-2017 at 17:00

I just tested a solution of aspirin, dissolved in acetic acid and adjusted to a pH of 7, with cobalt chloride and manganese chloride- no precipitate was observed.

Hector - 24-3-2018 at 02:02

after crystalising, the copper aspirinate deposited on the walls of the flask, as it can be seen from nice smooth shards. however, we got these goldish needle-like crystals that don't really fit any description.

the synthesis was done with copper sulfate and pure ASA

an EDS analysis was done and it shows the blue aspirinate and the needle-like golden crystals to have a somewhat similar composition (the gold needles contain less copper and more organic)

Lion850 - 13-9-2020 at 18:53

I also had a go at copper aspirinate, and then did some test tube checks with the metal salts I had available to see if anything else obviously reacts with sodium aspirinate. The copper first:
- First step to make the sodium aspirinate in solution:

Na2CO3 + 2C9H8O4 = 2C9H7O4Na + CO2 + H2O

- 4.7g NaHCO3 (baking soda from the local department store) was dissolved in 50ml warm water, obtaining a clear solution.
- Add 10g aspirin powder (lab reagent quality, bottles says "Aspirin") in stages to the stirred solution. Bubbles followed each addition, wait for bubbling to subside before adding more. All 10g dissolved, plus an 11th gram, but the 12th gram did not all dissolved. Filter the solution to remove the unreacted aspirin.
- 6g CuSO4.5H2O in 20ml water, heat a bit to fully dissolve. Slowly pour the CuSO4 solution into the sodium aspirinate solution to get the double displacement:

4C9H7O4Na + 2CuSO4*5H2O = C36H28O16Cu2 + 2Na2SO4 + 10H2O

- Stir for some 20 minutes, dark blue solution. Photo below.

1 color after double displacement.jpg - 746kB

- Vacuum filter and wash once with excess of cool water in the funnel. Photo below of the wet remainder. The filtrate had a very pale magenta color.

- Dry remainder on steam bath till weight reduction slowed to near nothing. Dry dark blue powder, 10g recovered. Photo below.

I then made another solution of sodium aspirinate by using the same procedure as above. I dissolved various metal salts that I have in the shed one by one in a bit of water in a test tube and added a bit of the sodium aspirinate to see if there was an obvious ppt. Observations:
- MnSO4 - no obvious reaction.
- (CH3COO)2Co - no obvious reaction.
- Cr(NO3)3 - no obvious reaction.
- Ce(NH4)4(SO4)4 - dark olive color ppt.
- (CH3COO)3Er - nothing.
- FeSO4 - solution turns dark brown color.
- Fe2(SO4)3 - solution turn very dark purple color with brown ppt.
- Ni(NO3)2 - no obvious reaction.
- TiCl3 - brown ppt, difficult to remove from test tube.
- SnCl2 - light yellow ppt, but when I retried on a larger scale I got a white very sticky mess.

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