neo_90
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synthesizing copper benzoate?
Hi! I'm new to this forum, and it looks great! I'm far from an expert, but hopefully I will be one day.
anyway, to my question:
I know that there is a way to make Cu benzoate from CuSO4 or from Cu carbonate. but, I have no idea on how to do it.
I have loads (at least I can get) of CuSO4, so thats the best way for me.
any ideas?
[Edited on 29-6-2006 by neo_90]
\"If we knew what it was we were doing, it would
not be called research, would it?\" -- Albert Einstein
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YT2095
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Copper Hydrodide and benzoic acid, it`s really that simple 
I take it you want this stuff for Pyro uses?
if that`s the case I suggest using KOH soln with your CuSO4 soln and mix the 2, copper hydroxide will form as a light blue ppt.
filter this it out and wash it, then add it to water again and a a stoichometric mix of benzoic acid, heat these together for a while, the benzoic
acid WILL dissolve when hot enough and react slowly forming copper benzoate in water.
dry this as normal.
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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neo_90
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okey, big thanks!
I'm guessing that NaOH will also work instead of KOH since that will also make copper hydroxide..
sorry for a stupid question, what is a stoichometric mix?
and another question, I've read that calcium benzoate will form benzoic acid when reacted with HCl, will sodium benzoate do the same? it also said
that there will be a "significant amounts of chlorinated benzoic acid derivates", will that benzoic acid still work? or is there some way to purify
the acid?
and yes, it is for pyro use..
\"If we knew what it was we were doing, it would
not be called research, would it?\" -- Albert Einstein
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YT2095
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aha, well if it`s for Pyro use, avoid Sodium salts at all costs!!!!
it will only serve to badly contaminate the color in fact just a few sodiom ions will swamp out what would ordinarily be a beautifull Green color,
hence I suggest using Potassium salts.
if you start with Sodium benzoate, there`s nothing you can do to avoid this, your only hope is to get it as pure as possible 1st time around.
hes the addition of HCl will indeed form insoluble Benzoic acid and sodium chloride.
you MUST wash this thouroughly!, an excess of HCL would be the best route.
and then plenty of deionised water, decant four or 5 times.
for the copper hydroxide do NOT use sodium hydroxide, it`ll be almost imposible to remove all the sodium as it locks up quite easily as the liquid
become turbid, KOH is ideal, it`ll impart very little to no color to your pyro effect.
stoichometric means you add them in the correct Molar weight proportions to get a 1:1 mix before you react them.
so you don`t end up with waste that`s hard to remove afterwards.
edit: as for the calcium benz, yes the HCl will work perfectly well just the same, and for Barium compounds in Pyro, you need not fear excess
Chlorine, it simple Brightens and makes the color more vivid
[Edited on 29-6-2006 by YT2095]
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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enhzflep
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neo_90 - you need to look up and understand stoichometry.
Imagine if you will, that water-mellons _always_ weighed 1kg and that oranges _always_ weighed 0.1kg.
Say you had to make a 1 to 1 mix of watermelons to oranges.
This is done by counting when you have only a few.
Buuuut, imagine if you had a truck full, or five trucks full, or a football stadium full 
In this case it would clearly be a pain to count them all. Soooo, if you were to weigh them then you could quickly determine the number of watermelons
you had. You could then take this weight and multiply it by 0.1 (since oranges are 1/10 the weight of watermelons in this example)
Stoichometry is about these basic principles. The weight that 1 molecule of any one compound has may be calculated. Then, when one wanted to have an
exact ratio of particles of one compound to another compound this could be done by weight.
i.e 1 Mole is the number of molecules of Carbon in ~12g of carbon
this is the same as the number of Hydrogen atoms in 1gm Hydrogen
this is the same as the number of atoms in 15.994 gms oxygen.
So, 2gms Hydrogen + 15.994 gms Oxygen --> 17.994 gms Water
2 Mols H + 1 Mol O --> 1 Mol H2O
The last equation is a stoichometric mix. - There is no excess of either H or O
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neo_90
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okey, so that’s stoichometry.. there is a swedish word for that too, just that I don't remember it..
anyway, big thanks!
I know that sodium can destroy a color very easily, but I didn't knew that it was so difficult to remove..
and green color? copperbenz with ammonium perchlorate will give you a wonderful blue color
thanks again!
\"If we knew what it was we were doing, it would
not be called research, would it?\" -- Albert Einstein
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YT2095
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I used the Barium as further example for sodium contamination, incidently, you can make barium benz the same way except you start with Barium
Chloride, as the sulphate is insoluble.
Good luck with it also, although I tend to use Barium Chlorate with the Ba Benz and K Chlorate with the Copper benz.
experiment with these anyway, that`s where all the fun is
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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Mumbles
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I had a go at preparing some copper benzoate today. I wasn't looking for yield, just properties. I first attempted reacting copper (II) sulfate with
benzoic acid. Me not thinking, the reaction didn't go through. I see very little chance for the reaction to work now that I think about it. The
starting materials are more stable than the desired products
I also gave it a shot with copper carbonate and benzoic acid. This proceeded slowly as would be expected.
I eventually broke down and used sodium benzoate and copper sulfate. Once the two solns were prepared and combined a beautiful turquoise ppct was
formed. I tried adding 1 molar equivalent and 2 molar equivalents to see if I could prepare a mono and di benzoate, which failed by the way. They
both gave the same product.
I found a page from the ACS journal about copper benzoate X-ray crystalography (see bottom of post for link). Normally I wouldn't be interested, but
they had a preparation. They prepared anhydrous copper benzoate by heating the trihydrate at 100C, and by heating the ethanol adduct at 90C. I tried
to prepare some of the ethanol adduct by adding ethanol to a small batch of crystals, which didn't really work. I am however leaving it to sit for a
while to see if I can get anything. Adding ethanol to the main batch just to get them to try faster yielded a noticeble color change from the nice
turquoise, to a very noticeable teal in some of the product.
Now the odd part. I decided to heat the copper benzoate to try to get the anhydrous product. I put it in a 100mL beaker and placed it on the hot
plate. It lightened in color a bit as it dried, which wasn't out of the ordinary. I noticed it starting to fume a bit, but just assumed it was
water. There was an odd smell in the air that I couldn't quite put my finger on. I chalked it up to the hot plate being not used for a while and a
bit dirty. So I'm letting it go along for a while and notice a bit of it turning a darker green. I thought that this must be the anhydride, similar
to how copper (II) chloride is brown, but the hydrated ligand form is blue-green. I let it go stirring occasionally and go up stairs to get some
water and a bite to eat. I return to the basement to a very distinct sweet burning plastic smell. I go look at my product and it is now all
red-brown.
Does anyone know what the product is? It is insoluble in water, and seems to dissolve very slowly if at all in 32% HCl soln. I wanted to say it was
CuO, but it's too red, and I don't know how it would be reduced to Cu2O. Is the anhydride really this red-brown and the odor from my hotplate? After
looking through the forum here a bit, I could almost swear the odor I observed was Phenol. It wasn't aromatic smelling like benzene, or the distinct
benzaldehyde odor. I was thinking it may be Benzoic Anhydride and CuO, but I can't find any odor data.
I remember reading that phenol can be formed by Benzoic acid decarboxylation, and that the temperature could be lowered by Cu (II) salts. Do you
think that it could have self catalyzed?
http://pubs.acs.org/cgi-bin/abstract.cgi/inocaj/1965/4/i09/f...
[Edited on 3-25-2007 by Mumbles]
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12AX7
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When I smell phenol I immediately think "phenolic resin!", as in bakelite, circuit boards, terminal strips, etc. There are a number of "burning
plastic smells", but of the "sweet burning plastic smells", I would have to compare that to something like polystyrene. Considering you started with
benzoate, I would guess benzene and decomposition products. I don't think phenol really counts as a "sweet burning plastic smell", but that could be
my experience with electronics instead.
What do biphenyl and benzoic anhydride smell like? It seems to me you'll have something like C6H5. + CO2 + Cu in there, or perhaps CO + Cu(I) and
mixed oxides. The decarboxylated phenyl I suppose would capture another to form biphenyl, or with CO and CO2 species around, perhaps various benzyl
oxy species (ester, diketone, anhydride, etc.).
Did you weigh the precipitate after drying, before this pyrolysis? Have you weighed it since? That'll tell you how much it decomposed (or for that
matter, how much oxidation is left).
Tim
[Edited on 3-25-2007 by 12AX7]
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Mumbles
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No, no masses were taken, short of the initial amounts of copper sulfate and sodium benzoate. It was just a qualitative type of experiment to see if
I could really prepare the anhydrous product. It was dried with heat while still wet anyway.
My problem is that I've never actually worked with phenol, so I am not sure what it smells like. The MSDS sheet says a "sweet tarry odor". I thought
that that could indeed be what I have. Biphenyl has a "pleasant, peculiar odor" which doesn't same a while lot. I still can't find anything of the
benzoic anhydride. Maybe the description of the odor I gave isn't perfect, but it's relatively accurate. I don't even want to think about it
anymore.
Whatever it was is kicking my ass. I got a touch of poisoning, or some bad effects. Pretty pounding headache, a bit of nausea, chest congestion,
exhaustion, dizzyness. All are consistent with biphenyl and phenol. Might not be the best test, but it's narrowing it down. Since I'm not having
seizures, coma, or death yet I should be alright. I'm feeling a lot better since last night.
[Edited on 3-26-2007 by Mumbles]
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Mumbles
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The poisoning lifted after about 24 hours. Now I just have some lung irritation and a cough. It always makes for an interesting conversation
starter. "Oh, no. I'm not sick, I just accidentally poisoned myself." You can tell you go to a party school when you said you accidentally poisoned
yourself, and they automatically assume it was from alcohol. 
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YT2095
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in my opinion, I would have said it was carbon Monoxide poisoning, when I`ve burned copper benzoate there is a slight smell and the copper is very
detectable but plenty CO comes away also.
\"In a world full of wonders mankind has managed to invent boredom\" - Death
Twinkies don\'t have a shelf life. They have a half-life! -Caine (a friend of mine)
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Mumbles
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It's hard to tell exactly what it was. All the symptoms are relatively similar as far as what I experienced. They all involve lung irritation,
dizzyness, nausea, and headache. As far as I know it could have been a cocktail of wondering body damaging things. I'm feeling better still, but the
cough stays.
I will probably give this another shot later next week, with of course less heat being used. Also, outdoors would probably be for the best.
[Edited on 3-28-2007 by Mumbles]
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