Author Topic: Reducing Agents  (Read 8564 times)

qasimta

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Reducing Agents
« on: February 17, 2011, 11:44:33 AM »
Hi,

I�m following your posts regarding the making of colloidal gold/Colloidal Silver and noticed the different types of reducing agents are being used. Coming from a non-chemistry background sometimes I struggle following and understanding the technicality behind the preference of one type over the other. Can someone summarizes the different reducing agents of choice and the difference and effectiveness of each and under what conditions.

From following your posts, I�m reading about:

Sodium Citrate
Glucose
Maltodextrin

I recall that someone mentioned that any sodium salt can act as a reducing agent as well. Is that correct.

Also, can these reducing agents be used to reduce other colloidal metals such as copper, zinc, platinum or palladium.

I also read about the hydrogen peroxide, sodium carbonate, starch as catalysts and stabilizers. But noticed sometimes they are used and sometimes they are not. Could�t draw a conclusion about their importance so far.

I had success making colloidal gold with the citrate and also with Maltodextrin. I was following the recipes very precisely but noticed that even if I add far more of the reducing agent than what has been specified it doesn�t fail. Is there any effect on stability if we are not very careful about how much of reducing agent we add?

Sorry for the long post but I was holding back throwing questions before doing enough reading on your forum.

Thanks,

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Re: Reducing Agents
« Reply #1 on: February 17, 2011, 08:49:03 PM »
Hi,

I�m following your posts regarding the making of colloidal gold/Colloidal Silver and noticed the different types of reducing agents are being used. Coming from a non-chemistry background sometimes I struggle following and understanding the technicality behind the preference of one type over the other. Can someone summarizes the different reducing agents of choice and the difference and effectiveness of each and under what conditions.

From following your posts, I�m reading about:

Sodium Citrate
Glucose
Maltodextrin

I recall that someone mentioned that any sodium salt can act as a reducing agent as well. Is that correct.
I don't know about any sodium salt, but probably.  Any metal except platinum can reduce gold.  But then sodium salt is not the same as sodium metal.

Quote
Also, can these reducing agents be used to reduce other colloidal metals such as copper, zinc, platinum or palladium.
I really haven't explored other colloids very much, so I do not know.

Quote
I also read about the hydrogen peroxide, sodium carbonate, starch as catalysts and stabilizers. But noticed sometimes they are used and sometimes they are not. Could�t draw a conclusion about their importance so far.
There are many reducing agents, and while they all reduce gold chloride to gold particles, they don't all produce the same result regarding particle size and shape.  I am on a permanent quest to find the best one :)  I can tell you though that peroxide is the absolute worst.

sodium carbonate + maltodextrin has worked best for me so far.

Quote
I had success making colloidal gold with the citrate and also with Maltodextrin. I was following the recipes very precisely but noticed that even if I add far more of the reducing agent than what has been specified it doesn�t fail. Is there any effect on stability if we are not very careful about how much of reducing agent we add?

Sorry for the long post but I was holding back throwing questions before doing enough reading on your forum.

Thanks,
Excess citrate usually resulted in ruined colloidal gold for me, as excess electrolytes in the colloidal gold reduce the repulsive forces which keep the particles apart.

Excess maltodextrin does not seem to hurt anything though. 

In general, I judge the citrate or carbonate by calculating the moles of citrate/carbonate needed and then increase it a little so that there is an excess of reducing agent.  This is to guarantee that no gold chloride will be left, as gold chloride is rather toxic. 

When using sodium citrate with gold, the citrate is both the reducing agent and the stabilizer.  When using carbonate with maltodextrin, the sodium carbonate is the reducing agent, and the maltodextrin is the stabilizer.
There is the unknown and the unknowable.  It's a wise man who knows the difference.

INOCENTFOREVER

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Re: Reducing Agents
« Reply #2 on: August 07, 2011, 09:07:56 AM »
kephra had you tried to make colloidal gold with magnesium chloride?, because i think it could work very well  the chloride would make the gold chloride, and the magnesium could reduce it! and if it work could it make some compound with the magnesium?

Offline kephra

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Re: Reducing Agents
« Reply #3 on: August 07, 2011, 12:31:47 PM »
Magnesium hydroxide (commonly called milk of magnesium) will be formed by the reaction of magnesium and water.  Nothing produced will be toxic though, and would be an interesting experiment to try.  If you try it, please post your results.

There is the unknown and the unknowable.  It's a wise man who knows the difference.

INOCENTFOREVER

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Re: Reducing Agents
« Reply #4 on: August 09, 2011, 01:30:46 AM »
kephra i just manage to obtain 100g of pure glucose powder  thinking to use it instead of the maltodextrine and syrup.
 if you were to make colloidal gold with sodium chloride and glucose using similar quantity of glucose instead of maltodextrine, how much glucose would you add to a 300ml formula of colloidal gold?   

 And by the way im about to make some colloidal gold with magnesium chloride, i will post the reults it imediatly!

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Re: Reducing Agents
« Reply #5 on: August 09, 2011, 02:34:29 AM »
Glucose is about 12 to 20 times more powerful as a reducing agent, than maltodextrin.  Therefore you have to use a lot less.  You will have to experiment with it, but I would start with the equivalent of about 25 mg of glucose.  This is just a guess, as a starting point.  Too much, and you will probably get larger particles (blue).
There is the unknown and the unknowable.  It's a wise man who knows the difference.

INOCENTFOREVER

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Re: Reducing Agents
« Reply #6 on: August 09, 2011, 06:22:55 AM »
this is a fragment of ( JOURNAL OF NANOPARTICLE RESEARCH )  very interesting book!

INOCENTFOREVER

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Re: Reducing Agents
« Reply #7 on: August 09, 2011, 06:34:28 AM »
Common Reducing Sugars:

Oxidation-reduction reactions are chemical processes that create energy, defined by the loss or gain of electrons in molecules. Oxidation occurs when a molecule loses one or more electrons, and reduction is when the molecule gains one or more electrons. This process is important in maintaining human life by creating an energy source for the body. This process requires a catalyst, called a reducing agent or oxidizing agent. Some types of sugars, or carbohydrates, are reducing agents. A reducing sugar contains aldehyde or ketone in its molecular structure.

Glucose
Glucose is the most common carbohydrate. This monosaccharide serves as the main source of energy for living things. It can be absorbed directly into the blood from the intestines due to its simple chemical structure. The presence of aldehyde makes glucose a reducing sugar. Glucose can be stored as starch in plants and glycogen in animals to provide an energy source later.

Fructose
Fructose is the sweetest of the common natural sugars. Many fruits and vegetables contain this monosaccharide. Its chemical structure is similar to that of glucose. The presence of ketone makes fructose a reducing sugar. Fructose combines with glucose to make sucrose, a disaccharide sugar. In addition, fructose is also produced commercially as a sweetener.

Lactose
Lactose is a disaccharide composed of glucose and galactose. This glucose component makes it a reducing sugar. Lactose is found in human and cow milk. The enzyme lactase breaks it down to provide energy. Some humans have low levels of lactase that can lead to a condition known as lactose intolerance, which can cause digestive problems.

Maltose
Maltose, also called malt sugar, is a disaccharide made of two molecules of glucose. This glucose base makes maltose a reducing sugar. It can be found naturally in germinating grain, starches, and corn syrup in small amounts. Beer producers allow barley, a basic cereal grain, to reach a high starch content by growing roots in a process called malting. The starch created in this process is then converted to maltose, which ferments to create the alcohol product.


Offline kephra

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Re: Reducing Agents
« Reply #8 on: August 09, 2011, 12:07:12 PM »
I have never used maltose or lactose, simply because glucose and fructose are so easy to obtain and work well.

Did you read the article I posted about making your own corn-syrup substitute (invert sugar)?

Another name for glucose is dextrose, and another for fructose is levulose.  These names derive from the way the sugars rotate light either right (dex-) or left (lev-).

Both glucose and fructose have the same chemical formula:   C6H12O6, the difference being in the shape of the molecules, and the arrangements of the chemical bonds between the C, H, and O atoms.

Dextrose Equivalent measures the reducing power of a substance relative to dextrose (glucose).  Maltodextrin has a low dextrose equivalent, which basically means that a low percentage of the molecules have the ability to reduce another substance.   
There is the unknown and the unknowable.  It's a wise man who knows the difference.

INOCENTFOREVER

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xx
« Reply #9 on: August 22, 2011, 04:08:34 AM »

xxx
« Last Edit: February 17, 2012, 01:16:15 AM by inocentforever »

INOCENTFOREVER

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Re: Reducing Agents
« Reply #10 on: November 16, 2011, 02:59:54 AM »
   

 in this photo i used ascorbic acid to reduce the gold, it woked but soon it agregated.

 A ph of 7.5- 8 works much better with gold! making it  stable and no changes in color! So no more AA !.
« Last Edit: November 16, 2011, 03:07:42 AM by inocentforever »

Offline kephra

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Re: Reducing Agents
« Reply #11 on: November 16, 2011, 12:10:30 PM »
Yes, acids don' work well.  I have used sodium ascorbate, which is buffered vitamin C, and it worked ok in the short term, but after weeks, there was a lot of sediment.  So I looked for something better.

That's good looking product in you photos!
There is the unknown and the unknowable.  It's a wise man who knows the difference.

INOCENTFOREVER

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Re: Reducing Agents
« Reply #12 on: November 17, 2011, 02:33:23 AM »
the silver was made with good distilled water and one silver anode and one copper catode heating the water almost to boil for 19 minutes  to have enough silver oxide in water, then two drops of inverted sugar and in 5 minutes you will have yellow Colloidal Silver!   
 
 there was no salt added, no electrolites just  distilled water and two drops of invert sugar!  or syrup

INOCENTFOREVER

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Re: Reducing Agents
« Reply #13 on: February 11, 2012, 08:51:09 PM »
Glucose is about 12 to 20 times more powerful as a reducing agent, than maltodextrin.  Therefore you have to use a lot less.  You will have to experiment with it, but I would start with the equivalent of about 25 mg of glucose.  This is just a guess, as a starting point.  Too much, and you will probably get larger particles (blue).


Hello everybody,  last week i tried to make some colloidal gold adding magnesium chloride instead of sodium chloride ( salt ). 

70 mg magnesium chloride
50 sodium citrate
2 drops syrup

250ml

 ------------------at 12 minutes of electrolysis big red flakes started to apear, and precipitated ( not a red solution)
 
   There was not a uniform dispersion of particles like in the sodium chloride recipy.

I prefer not to waste the gold, so i didnot attempt to do a second try!    its easier with regular salt!

 So i dont recomend to try it with magnesium chloride!


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Re: Reducing Agents
« Reply #14 on: February 11, 2012, 10:25:22 PM »
Yeah, that was an interesting experiment.

Here is my hypothesis as to what happens.

There is a huge difference between sodium chloride and magnesium chloride.  Both of them will plate out onto the cathode, and both will react with water as an hydroxide, but sodium hydroxide is soluble while magnesium hydroxide is not.  Because of this difference, the amount of ionic hydroxide drops drastically during the electrolysis with magnesium whereas the amount of ionic hydroxide with sodium remains constant.  Because of the reduction in the hydroxide, all of the current will be carried by the chloride, making the gold chloride reaction far too fast.

If I were going to try this experiment, I think I would try much lower current, say 15ma (since thats what my regulators are set to).
There is the unknown and the unknowable.  It's a wise man who knows the difference.