34 replies to this topic

[sasman]

I have just read a few threads on the PML someone mentions wanting tp make Copper benzoate..I have read the article in AFN written by David Blesser..about the New Blue..and preperation of copper benzoate..

In the PML digest the Dawn Trader replied saying something about it's not as easy to make as suggested??

I will shortly be needing some Copper benzoate to make some of this NEW blue..So i am interested in making a few Kg's.. What difficulties are there?

I would have thought ,if using pure Copper sulphate and Potassium benzoate then the end product would be pure?.. and as long as the precipitate is washed a few times to remove all traces of the potassium salt.. should have no effect on the flame colour?..

Anyone used/made copper benzoate..please let me know...

Also is it worth the effort in making it for a nice blue?..or can another more easily obtainable copper salt be used to make a very good blue..

I also read the Skylighters bulletins on Blues...Paris green was rated as making the best blues...but to me thats worthless as it far to expensive for practical use..


I would appreciate any tips/advice on the preperation of this chemical..

[Andrew]

A few things I can think of, from recolection, potassium sulphate is not that soluble. So recrystalisation might be a little difficult, is copper benzoate very soluble? I don't know. There are also a few variations of copper benzoate, which variant does this method produce?, this could mess up your stochometry. I've never really liked recrystalisation, the yields are too low, I don't like waste, I feel all sad and glum at the thought of waste or all the work involved in reclaiming it .

I would suggest using a basic copper compound, like copper hydroxide or copper carbonate, and add it to dilute benzoic acid. The carbonate would be best as it is not very soluble, so you can tell easily when the batch has reached completion. It is also 100% efficient on starting materials, (if you go a little too over with one you can always add a little of the other), yipee .

Not on the topic of making, but, using a Benzoate is quite a good idea, you get a fuel and a colourant in one. A bit like using oxidisers like barium nitrate etc. I can see how it gets a better colour, there is less inert crap in the way to start with.

[fishy1]

"Copper benzoate is easily prepared at home from a solution of sodium or potassium benzoate and a soluble copper salt. When these solutions are added together a green precipitate of copper benzoate forms. This is filtered, thoroughly rinsed with hot water and left to dry."


has anyone tried this?

and also, does anyone know the solubility of copper benzoate? i've looked, but i can't find it anywhere.

[paul]

In this skylighter article http://www.skylighte...cle.asp?Item=12 the dihydrate is refered to as "slightly soluble" only.

Could not find any further information on that. Sorry.

[lord_dranack]

Don't know the exact figure, but have seen it classed as "slightly soluble".
The same table also classed copper (II) fluoride as slightly soluble, and to give an idea of what this means it has a solubility of 4.7g per 100g cold water.

[Mumbles]

The water remaining after the precipitation of copper benzoate is nearly clear. This indicates very little copper dissolved in the water. In water, copper forms a complex [Cu(H2O)6]+2 which is fairly colored.

This is something I have been meaning to try and synthesize. It seems to have some ideal coloring characteristics. If you want to drive off the water of hydration, you have to heat it to 110C. Perhaps the anhydrous form would give even better coloring characteristics.

[sasman]

I bought a large drum of potassium benzoate ready for when i make some Copper Benzoate but still not made any yet..Has any member made any New blue ? and if so is it worth the hassle in making it..

How does the Blue compare to a good Chlorate blue?. The only blue i made sofar was a a Perchlorate blue and i was not impressed with the colour more blue white than a nice dark blue..

[fishy1]

I bought a large drum of potassium benzoate ready for when i make some Copper Benzoate but still not made any yet..Has any member made any New blue ? and if so is it worth the hassle in making it..

How does the Blue compare to a good Chlorate blue?. The only blue i made sofar was a a Perchlorate blue and i was not impressed with the colour more blue white than a nice dark blue..

skylighter say it's meant to be

B16

Ammonium perchlorate) 82

Copper benzoate 18

Dextrin +5



D. Bleser's blue from AFN #64, Jan. 1987 modified with dextrin binder. Good ignition. A simple, but effective, composition employing a single entity fuel/color donor. Color saturation was very good, as was burn rate. One of only three useable ammonium perchlorate compositions tested, its primary disadvantage may be the limited availability of copper(II) benzoate.



seems to meet all my requirements, anyone got a video of it?

[helge]

I think you could make the following types of copper benzoate:



For type A you can simply add any Copper(II)-salt to the sodium benzoate.
Type B should be harder to prepare since Copper(I) isn't stable in aqueous solution. It will form Cu2+ and Cu. But if copper(I)benzoate is hardly soluble (is it?) the preparation of copper(I)benzoate can be successful.

To get the Cu(I) you have to boil copper in hydrochloric acid. this way CuCl is formed. If you don't boil you'll get CuCl2.
To the freshly prepared Cu(I) solution you can add sodium benzoate and maybe Copper(I)Benzoate is formed.
I have not tried this yet, so i don't now whether it works, but I think Copper(I)benzoate will make an other blue than the easier to make Copper(II)benzoate.

regards, helge

Edited by helge, 13 January 2006 - 05:43 PM.

[Mumbles]

Copper (I) Chloride isn't soluble in water. So, if any copper (I) benzoate would be formed, it would depend on the Ksp of each of the salts. I would recomend something like potassium benzoate or straight benzoic acid(actually cheaper) instead of sodium benzoate for making copper benzoate.

[alany]

I prepared some from Sodium Benzoate and Copper Sulfate. I had a lot of trouble washing out the Sodium without dissolving the most of the Copper Benzoate. Using Potassium Benzoate makes it far easier.

It won't whistle in rockets with Potassium Perchlorate, but it does give them a pale blue flame.

[sasman]

I have asked this somewhere before ..is it worth the hassle to make copper benzoate.. for a good blue..I have read Skylighters news letter about there blues.. has any member made some Ammonium perchlorates blue..is it realy good?..

[karlfoxman]

I am trying out AP blues and the results seem very good so far, i have test samples to cut into microstars and will post the results. The formulas i have tried are:

Pihko AP #1
Pihko AP #4
Lancaster AP #3
Baechle System 5: Indigo

Up close the above three burn bright blue, Pihko AP #4 burns quite fast but has similar colour/saturation as #1. The indigo burns a deeper blue as to be expected.

None of the above use Copper Benzoate, i am trying to get hold of Cu oxychloride as i think i will get the best results with this.

[YT2095]

I`m currently making another batch of copper benzoate, I use a strong but not saturated soln of copper sulphate and Ammonium benzoate.
add the one to the other slowly while mixing well.
the PPT is instant as a light turquoise blue, allow the ppt to settle and decant it off, add water and shake well and allow to settle again and decant, same again and then filter off the liquid to leave your Copper benz, I`ve done it dozens of times and with perfect results each time, the stuff really isn`t all that soluble at all.
I`ll add some pics (or link to them) when I`ve done this batch and post them in here.

[MMMMMM Pyro]

You dont need to buy the Copper Oxychloride, make it! All you need is CuCl2 and NaHCO3! I cant be bothered to dig up my notes but some basic chemistry will get you the weight of reactants you need.

Regards,

Mike