Differentiating ZDDPs

[nick8765]

Hello

Is Zinc O,O,O',O'-tetrakis(1,3-dimethylbutyl) bis(phosphorodithioate) a primary or secondary ZDDP (CAS Number: 2215-35-2 ) ?

Is Phosphorodithioic acid, mixed O,O-bis(1,3-dimethylbutyl and iso-Pr) esters, zinc salts a primary or secondary ZDDP (CAS Number: 84605-29-8) ?

What is the best way to differentiate ZDDPs? Is there an easy way?

 

[kschachn]

Why do you want to differentiate them? Do you have a background in chemistry?

 

[nick8765]

No backgroung in chemistry. When I see them in MSDS I wish to be able to differentiate between them.

Some say primary is better for diesel engines.

 

[kschachn]

Well you’ve already differentiated them by the name. Are you asking how to do this analytically? Such as through FTIR or gas chromatography?

Do you have an oil sample and you want to find out which one is being used?

 

[nick8765]

No. I saw them in msds of the oil I'm presently using. First one in concentration less than 0.6%, second one less than 0.3%.

I'm only interested how to differentiate them from name if possible? Which one is which type?

 

[kschachn]

Primary vs Secondary ZDDP

First post. Been lurking the site for years and finally joined. I've been researching this for a little while. I know a little about their function, that primary has a slower consumption rate but harder to activate, and secondary is the opposite. What I'm hoping to find out is the difference in...

bobistheoilguy.com

 

[RDY4WAR]

Most all standard API add packs have a blend of both primary and secondary ZDDP, usually about 70% primary. There's more factors than just ZDDP itself. Ensuring synergy with detergents, extreme pressure, and friction modifier additives is one such factor.

A ZDDP concentration in an oil that's entirely secondary alkyl is rare. It's usually only something you'll find in "pump and dump" oils that like the greater reactivity and aren't worried about stability such as break-in oils and dedicated racing oils.

 

[kschachn]

Most all standard API add packs have a blend of both primary and secondary ZDDP, usually about 70% primary. There's more factors than just ZDDP itself. Ensuring synergy with detergents, extreme pressure, and friction modifier additives is one such factor.

A ZDDP concentration in an oil that's entirely secondary alkyl is rare. It's usually only something you'll find in "pump and dump" oils that like the greater reactivity and aren't worried about stability such as break-in oils and dedicated racing oils.

I noted in the thread I linked this was your first post to Bitog

 

[nick8765]

Yes, I get it, it is mostly mixed.

However, I was only able to find this in ECHA Registration Dossier for Phosphorodithioic acid, mixed O,O-bis(1,3-dimethylbutyl and iso-Pr) esters, zinc salts a primary or secondary ZDDP (CAS Number: 84605-29-8) under Data Matrix for Read Across from Analogue:

"ZDDP containing 95% isopropyl (C3) dithiophosphate ligands + 5% containing mixed isopropyl and 1,3 -dimethylbutyl dithiophosphate ligands"

Would that make it a 95% primary?

 

[kschachn]

Yes, I get it, it is mostly mixed.

However, I was only able to find this in ECHA Registration Dossier for Phosphorodithioic acid, mixed O,O-bis(1,3-dimethylbutyl and iso-Pr) esters, zinc salts a primary or secondary ZDDP (CAS Number: 84605-29-8) under Data Matrix for Read Across from Analogue:

"ZDDP containing 95% isopropyl (C3) dithiophosphate ligands + 5% containing mixed isopropyl and 1,3 -dimethylbutyl dithiophosphate ligands"

Would that make it a 95% primary?

Just an honest question, do you understand any of what you're posting? Or is this just copy-and-paste? I ask because if you don't understand the question you're not likely to understand the answer.

What did you think of the thread I linked? Didn't that answer your questions?

 

[nick8765]

Well, I am trying to understand. Of course its a copy paste. I've read the thread. It only raised more questions.

 

[RDY4WAR]

Isopropyl is a secondary alkyl group because it's created when the second carbon atom of a hydrocarbon (ie: propane) loses a hydrogen atom. If the primary carbon atom loses a hydrogen atom, it's a primary alkyl group. (n-propyl)

ZDDP is created by reacting phosphorus pentasulfide with one or more alcohols to make dialkyldithiophosphoric acid. Zinc oxide is then added to neutralize the acid and form zinc dialkyldithiophosphate (ZDDP).

When ZDDP is encounters iron surfaces in boundary lubrication, the sulfur from ZDDP reacts with the iron to form iron sulfide, a hard protective coating. Note that this does not happen on aluminum parts. With increasing heat and pressure, the phosphorus part of ZDDP breaks down into short chained metaphosphates which become longer toward the surface forming a phosphate "glass" for anti-wear barrier.

The role of the alkyl groups is stability. Secondary alkyls, shorter chaining, are less stable and thus more reactive at lower temperature and pressure. This is great for a drag racing engine that might never go over 150*F oil temp, a new engine going through break-in, or something like a cup engine that's going to dump the oil after every race. It's not something you really want in a daily commuter going 5k+ miles between oil changes. The primary alkyl ZDDPs will be more stable for longer intervals, have better synergy with other additives, and have better anti-oxidant properties. Also, there's some research that shows primary ZDDPs are less damaging to emissions systems if consumed, but I would have to verify that.

 

[nick8765]

Thank you. This is taken from MSDS of one 505.01 5W-40 oil for 10k miles intervals for VW Pumpe Düse. It is mid saps so 0.9% should be 900 ppm ZDDP.

So then it seems at least 285 ppm of it is secondary

 

[MolaKule]

Hello

What is the best way to differentiate ZDDPs? Is there an easy way?

Bring a 4 oz. sample of each to the lab and do a series of tests via Forensic Analysis testing.