G.C. on GC GOLD - Base oil analysis

[Tom NJ]

Hi Primus,

Hexatriacontane in a linear C36 alkane, a wax with a melting point of 75C. The term "branched hexatriacontane" could be a clever way of describing a PAO for the MSDS, but it would only describe the trimer of a 1-dodecene type alpha olefin. This is only a portion of the PAO, so the total PAO would be more than 20-50%. If the trimer is say 45% and the tetramer is say 20% and the pentamer say 5%, then the total PAO would be 70%. Our analysis showed the trimer to be the majority, followed by some tetramer and pentamer, consistent with a blend on a 4 and 6 cSt 1-decene PAOs or perhaps a 5 cSt 1-Dodecne PAO.

So, the missing 42% is probably mostly these other higher portions of the PAO, which may not be required to be listed on the MSDS as often higher polymers need not be listed.

Tom

 

[Tom NJ]

Hi glxpassat,

Yes I have read this before, but it doesn't make sense.

PAO is made by polymerizing alpha olefins, and neither the alpha olefins nor the finished PAO have any acid or alcohol groups.

Esters are made by reacting acids and alcohols. Many synthetic acids are also made from alpha olefins, but neither the acids nor the finished esters are chemically related to PAOs, and are not derived from them. Therefore I don't get the term "PAO based esters". Perhaps it was created as a layman's description.

All esters should show a strong C=O absorbance on the FTIR but we only see a little. I suspect this oil may contain a relatively small quantity of a heavy polymeric ester like the Ketjenlubes, which are used at additive levels to contribute lubricity.

Tom

 

[glxpassat]

Tom,

Maybe this is a better description. It's refered to as a co-oligomer: a “high molecular weight high viscosity PAO”

This place has some details on it - http://www.mitsuichemicals.com/luc.htm

I wish Molakule would chime in here!

 

[Tom NJ]

Hi glxpassat,

An oligomer is just a short polymer, that is, the product of molecules that react with others like it to build larger molecules of repeating units. It is often applied to PAOs, which are oligomers of alpha-olefins. The Lucant products you linked to are "co-oligomers", meaning they are oligomers of differing molecules, in this case ethylene and alpha-olefins. Their properties are very similar to heavy PAOs as the structure would suggest. Neither are esters and neither have any polar groups. It is the term "PAO Ester" or "esters derived from PAOs" that I don't get.

There are ester oligomers, such as the Ketjenlube products, and these may be what they were referring to. I suspect they may have coined the term PAO Esters as a way of comparing them to PAOs for descriptive purposes.

It would not surprise me if GC contained Ketjenlubes - I know they are used in some high performance motor oils - but the small C=O absorbance on the FTIR suggests the dosage is small.

Tom

 

[Al]

Thanks for all of your efforts Tom. Can't say I understand everything. But I see the information I was looking for. I'm getting what I paid for with GC.

 

[GMorg]

I have no idea if the following applies to the PAO ester question above, but olefins can be converted to an alcohol via the "OXO synthesis" process. olifen + carbon monoxide + hydrogen on cobalt with heat. See link below. I would think that oxidation of the of the intermediate aldehyde could direct some proportion of the reaction to a fatty acid. If the aldeyde can be oxidized efficiently, one may be able to make both the acid and the aldehyde from 1-decene (or any other -ene). I'm just guessing, but it seems that one could get to a "PAO ester". I have no idea how favorable the kinetics are though...

http://www.fischer-tropsch.org/primary_d...248_45_sec7.htm

 

[GMorg]

Correction: " both the acid and the aldehyde from 1-decene" should read "both the acid and the alcohol from 1-decene"

 

[glxpassat]

GMorg, the report mentioned "PAO derived ethoxylated esters", whatever that means... It's greek to me, but I thought it might be refering to the process used.

 

[Tom NJ]

Hi Gmorg,

You are correct that alcohols and acids can be made from olefins like 1-decene, but not from PAOs. It would seem to me that if it is called a PAO ester or ester derived from PAO that the PAO, not the olefin, should be the starting point. I think the term was designed to convey that the ester is built "like" heavy PAOs in that it is a high viscosity oligomer, rather than that the ester was actually derived from PAO as the name implies.

Tom

 

[pzev]

I wish the M1 thread was this civil

 

[Tom NJ]

Quote:

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I wish the M1 thread was this civil

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Hi pzev,

I guess emotions are much higher on that issue.

Tom

 

[Eddie]

Thank you Tom for the very informative explanation of GC. One comment I would make is that since the oil sample is so very small the oil must be mixed well. Oil additives will over time tend to separate. I personally have observed this in one quart containers. GM now has requested that bulk oil containers used in their shops be of a size that will be used within a certain time frame because of additive separation. Ed Hayes

 

[Tom NJ]

Hi Ed,

We shake all sample bottles before working with them just in case there is additive separation. I must say though that any company that markets a lubricant with additive instability hasn't done their development job properly. We cold and hot cycle all formulations, as well as long term cold storage, before releasing the product to the market. Sounds like they need to use more ester!

Tom

 

[55Test]

So...gold GC is still 100% PAO? As good as Green?

 

[daman]

Quote:

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So...gold GC is still 100% PAO? As good as Green?

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X2???

 

[55Test]

Yoohoo...?

 

[Marshalus]

That is correct from what I understand.

 

[55Test]

Sweet. I'll be using it next oil change, and I'm gonna try to 10000 miles.

 

[BTC]

This discussion is over my head, but I've decided to give GC a try over the Amsoil I've been running and I have a couple of questions. I'm sure they've probably been asked several times, so I apologize in advance.

I'm assuming the Gold is actually gold and the Green is actually green. Is there any signficant difference other than the color? Is one better than the other? Can they be differentiated based on packaging and are both available at Autozone. I checked the availability today and noticed that the bottles of whatever they had now say European Formula.

Is GC available in weights other than 0W-30?

Thanks

 

[BTC]

I found the answer to available weights in another thread.