XTOL patented?

[gainer]

Patrick;

The top graph is of binary, not ternary mixtures. I misread the graph and I apologize. This is a plot of the melting point of the 3 Ethanol amines as a function of water content.

The second plot is actually a pair and I missed the second plot. You need both to get pH vs concentration.

Although I was wrong, neither has a direct impact on our discussion. What we need is that data as a binary mixture of DEA/TEA in water at different concentrations and the MP and pH data. Silver halide solvent capacity would be good as well.

Alan;

Thanks for the clear explanation for the non chemists out there. Since we are generally faced with 95% TEA, then the DEA is a minor constituent and that is why I was surprised by the MP increase that Patrick reported above.

PE

I get the 99% TEA from www.chemistrystore.com. I guess soapmakers like to have the purest available stuff.

 

[sanking]

I get the 99% TEA from www.chemistrystore.com. I guess soapmakers like to have the purest available stuff.

What is the other 1%? Would that be DEA?

Sandy

 

[Kirk Keyes]

I have some in the group where I work, but unfortunately I would not be able to use them on a personal project.

Even better, I have mass spectrometers too, but again they would not be available for personal projects.

Me too, on both accounts. I even run a mass spec!

 

[Kirk Keyes]

PE is right, impurities always depress the melting point.

My mistake. I seem to have mentally blocked out some of P-chem class...

 

[gainer]

What is the other 1%? Would that be DEA?

Sandy

I don't know, but the commercial TEA is nominally 15% DEA.

It is stated by Dow that TEA (Trolamine 99% NF Grade) meets the requirements of the applicable National Formulary monograph. "Trolamine" is another name used for TEA.

 

[gainer]

My mistake. I seem to have mentally blocked out some of P-chem class...

Just remember sea water. Now if someone will tell me how the Maker knew to make water expand just before freezing so as to float, thus keeping the world's oceans from freezing solid----. Oh, well.

 

[gainer]

Sandy, TEA is also hygroscopic, so it will be difficult to keep at least some water out of it.

 

[gainer]

If you are familiar with the use of Mason jars and lids in home canning, you could make use of that technique to store some TEA. Fill a Mason jar nearly full of TEA and heat it to the boiling point of water, not of TEA, with the cap loosely in place. When the cap quits flapping, practically all the water vapor will be gone. Turn off the heat and screw the lid tight. If the seal is good, the center of the seal will pop down.

 

[Kirk Keyes]

http://www.make-digital.com/make/vol14/?pg=137
http://www.creative-technology.net/MAKE.html

Lee

Nice gadget, and I do have an Arduino laying around. But this is a simple spectrophotometer and the only way it could help with this problem is to have a liquid chromatograph hook up to it to separate the TEA from the DEA and then you could use this project as a simple detector, but you'll need to add a UV LED into the detector light source array.

 

[Kirk Keyes]

Fill a Mason jar nearly full of TEA and heat it to the boiling point of water, not of TEA, with the cap loosely in place.

Let's remind people that Mason jars are not Pyrex and you probably do not want to heat them on a hot plate. They are made to be placed in a pot of boiling water.

 

[gainer]

Let's remind people that Mason jars are not Pyrex and you probably do not want to heat them on a hot plate. They are made to be placed in a pot of boiling water.

Good point. They will have TEA in them, which boils at a much higher temperature than water. Where I live, at about 1000' above sea level, everything boils a little cooler on average. The idea might not do anything but satisfy some scrupulosities. The 99% grade will be about as good as we can afford or need for most of us.

I believe Mason Jars are of tempered glass. The hand blown tableware my grandfather made in his factory were run through a lehr which was hot at one end and cool at the other. I should say "crawled" not run. They were tempered to relieve stresses by cooling slowly over a period of about 24 hours.

 

[Aurum]

I get the 99% TEA from www.chemistrystore.com. I guess soapmakers like to have the purest available stuff.

Yes we do. (And I don't mean this in a sarcastic way either)

Triethanolamine, and DEA compounds such as Cocamide DEA, were considered trouble and a half nearly 20 years ago before I joined the industry.

There was a big push to reduce DEA residues in detergents, and TEA became very unpopular due to the risk of forming Nitrosamines in product, especially in conjunction with formaldehyde donor preservatives

TEA, never really recovered its use in cosmetics, but is still used in certain areas, as it is irreplaceable. For most regular uses Caustic Soda is used instead.
These days its often used for neutralising high alcohol carbomer gels, as caustic just shocks out

 

[Lee L]

But this is a simple spectrophotometer ...

Ergo the smiley. Of course it won't replace a real lab machine, but it did get you thinking along the same lines I was headed down... more LEDs in UV, perhaps two different reds, an aqua/cyan, etc to enhance the ability to discriminate among fluids. Mainly thought you might be interested in the ideas involved.

Lee

 

[Kirk Keyes]

Lee, actually what's missing is some sort of chromatography machine to separate out the TEA from the DEA. And all I think you would need at that point is a UV LED to make the detector, which could be done with that device. The detector is the easy part there, getting high pressure and a chromatographic column are the hard part.

Thanks for the link. Back to the Arduino project we talked about a while ago - I've still got to hard wire my one-sensor temp probe up and the Arduino program is done - it's a little buggy getting the thing to start making rereadings on the Arduino side, but it works, and it works really well. We made it so it can read up to 3 sensors at the same time. Now I just need to take that data into the Project software and log it so I can pull it up in Excel.

 

[Jordan]

Actually, a quick and dirty way to estimate diethanolamine contaminants in TEA would be with a ninhydrin test, as DEA would give a positive response, while TEA would not (IIRC -- ninhydrin only responds to primary and secondary amines) That plus the home-made spectrophotometer would probably do the job for anyone who cares to go out and actually do this stuff.

As far as the whole melting point discussion is concerned -- is the "frozen" TEA crystalline, or more like a gel? TEA has an interesting structure with a lot of internal hydrogen bonding (which also explains its abnormally low pKa). I can easily see it forming a gel with other strong hydrogen-bonding amines in the right proportions and concentrations, not necessarily following any melting-point depression rules (which relate to disruption of crystal lattices IIRC)

 

[Photo Engineer]

Jordan;

The "frozen" TEA I have is visibly crystalline and as hard as a rock. It is yellow in color. The liquid TEA looks like vegetable oil. Clear and slightly viscous.

PE

 

[sanking]

Jordan;

The "frozen" TEA I have is visibly crystalline and as hard as a rock. It is yellow in color. The liquid TEA looks like vegetable oil. Clear and slightly viscous.

PE

The attached .pdf file from DOW Chemical has some interesting information about the various types of TEA produced by this company.



Sandy

 

[Photo Engineer]

Interestingly enough, both of my samples had the same label on the drums from which they were pumped. Two drums, one identical label on each but two "results". It was the same supplier as well.

PE

 

[Jordan]

Interestingly enough, both of my samples had the same label on the drums from which they were pumped. Two drums, one identical label on each but two "results". It was the same supplier as well.

PE

This kind of stuff seems to happen all the time around here too -- and it's especially noticeable with materials that freeze near room temperature.

 

[Kirk Keyes]

The attached .pdf file from DOW Chemical has some interesting information about the various types of TEA produced by this company.

According to Dow, "commercial grade" TEA can contain up to 15% DEA. That's a lot of variation/contamination. Even Patrick's beloved 20 Mule Team Borax has a much lower range of variation, and there it's probably mostly water.

It would be interesting to have someone collect and compare different batches of TEA and see what pH variations there are.

 

[gainer]

According to Dow, "commercial grade" TEA can contain up to 15% DEA. That's a lot of variation/contamination. Even Patrick's beloved 20 Mule Team Borax has a much lower range of variation, and there it's probably mostly water.

It would be interesting to have someone collect and compare different batches of TEA and see what pH variations there are.

The way I read Dow is that Commercial TEA is a mixture of Tri- and Diethanolamine, approximately in the ratio of 85/15. It is designed for certain uses, but not to my knowledge touted for our sort of photographic use. It is not necessarilly an inferior product. I'm pretty sure Dow would not recommend it as an analytical reagent. It may in fact be superior to analytical grade for its intended uses.

 

[gainer]

BTW, I'm sure you know you will not have a proper pH measurement without water

 

[Kirk Keyes]

BTW, I'm sure you know you will not have a proper pH measurement without water

Of course, a 1:10 dilution could be made.

 

[Kirk Keyes]

The way I read Dow is that Commercial TEA is a mixture of Tri- and Diethanolamine, approximately in the ratio of 85/15.

Pat - please look closely, there are equal signs in there with the greater than and less than signs. I'm pretty certain you know how to read those statements.

For commercial grade TEA, it actually says:

TEA >=85%
DEA <=15%

That means that there is a minimum concentration of 85% for TEA, and at a maximum, 15% of DEA. So the actual product purchased could range from any ratio of 85% TEA/15% DEA to 100% TEA/0% DEA, as it is stated.

It's more than "approximately in the ratio of 85/15", they are saying it never has more than 15% DEA, I take you statement of "approximately" to mean that the concentration of the DEA will vary around the concentration of 15%. It doesn't say that.

Whether it actually makes it to 100% TEA on some occasions, it may not. And whether it is always at 85% TEA with 15% DEA, is may be. Perhaps 90% TEA/10% DEA is a more commonly produced mixture, but there's no way to tell from that sheet.

They are leaving a HUGE range of possible compositions available to themselves for what they actually supply. And who knows what other manufacturers produce.

If you really want to have a better idea of what you are getting, the TEA 99% grade or the TEA 99% LFG grade are better choices.