Additives - Detergent - Dispersants

[MolaKule]

Bob has asked me to jump in here with my hipboots strapped-up and post some QOTD's.

Since many here on the BITOG seem interested in additives and their affects on engines and other machinery, I thought we could start out with this topic. After we have posted additive QOTD's, then we can move on to other, and hopefully, interesting topics as well.

In addition, if you have some topics you would like to see explored, send me a PM, or contact Bob or one of the Moderator's.


As you know, solid dispersions and oil soluble additives are used to enhance or improve the capabilities of the total oil formulation. Additives were first introduced into engine oils in the 1930's, and today this segment of the economy accounts for billions of dollars in revenue.

Topic "Uno"
One of a "class" of most widely used additives are the Calcium and Magnesium Sulfonates, and phenates, made by the sulfonization or phenation of alkylbenzenes and base metals, and mixed with dispersed calcium carbonates. These same additives are also used to neutralize acids and prevent corrosion. The sulfonates in the additives surround sludge and other "wornout" hydrocarbons and sweep these "useless" molecules into little communities until drain time. The net effect is to "sweep-and-hold" noncontributing hydrocarbons.
What do we call this class of Additive?

[ July 22, 2003, 01:27 PM: Message edited by: Patman ]

 

[Pablo]

Detergents that have an antioxidant role.

[ May 29, 2003, 03:05 PM: Message edited by: Pablo ]

 

[BOBISTHEOILGUY]

I'm incline to think Pablo is right.(at least that'll be two of us wrong if ya miss it huh Pab.

)

 

[JHZR2]

My guess os this:

The additives in the oil, such as described are a type of surfactant which allign themselves into a micellular structure. These micelles are electrostatically attracted to each other and to the impurities, due to the charge on the surfactant ends. The surfactants will arrange themselves in different structures, often in a wormlike or spherical micellular structure. The interior volume of a spherical micellular structure would contain all the various impurities (these things are still extremely small overall), but would mostly be homogeneous groups of surfacats attracted to the impurities and each other in such a way that the impurities are held together and not free in the oil.

Surfactants are charged molecular structures, with a hydrophilic and hydrophobic end, and ecasue of this, will also attract to free floating H+ ions (acids). Through weak Hydrogen bonding, or some othr attractive mechanism, the H+ ions will not be free anymore and therefore will not have an 'acidic effect'.

How close or far am I?

JMH

[ May 29, 2003, 11:00 PM: Message edited by: JHZR2 ]

 

[MolaKule]

You guys are good.

Deposits and and wear limit the useful life of gas and diesel engines, and the control of these deposits are the main function of detergents-dispersants . These chemical additives keep sludge, carbon and other deposits suspended in the oil.

The sulfonates and phenates were some of the earliest ash-type detergents-dispersants, and are still used today in some formulations. In the overbased phenates, the extra calcium is believed to be incorprated as carbonate chains. Overbased calcium alkyl phenates provide the main basicity for neutralizing corrosive acids and to provide some detergency and deposit piston control under high operating temps.

Later, ashless dispersants were developed to control deposit formation on valve stems, spark plugs, and top ring lands. These new ashless-type detergent-dispersants are the Succinimides, succinate esters, polymeric detergents, and the alkylated Amines.

Overbased phenates have also been shown to reduce oxidation potential in formulated motor oils.

Some new Viscosity Index Improvers also incorporate dispersant chemical groups as well.

[ June 02, 2003, 12:48 PM: Message edited by: MolaKule ]

 

[Drstressor]

"the extra calcium is believed to be incorprated as carbonate chains"

Ah, an alchemist!

 

[MolaKule]

If you examine the generalized phenate structure,
you have the oxygen, Ca, oxygen, a Carbon Oxygen linkage (double bond), an oxygen atom, and then another Ca atom, hence the above statement.

In addition, the overbased calcium alkyl phenates are generally used with other detergent and inhibitor additives to neutralize acids and provide additional detergency.

 

[Terry]

Go Mola Go ! What a website ! Gold for free. Those that have ears to hear, listen !

 

[Drstressor]

I know what you mean -- you just didn't say what you meant.

 

[MolaKule]

DrStressor,

The previous statement was correct:

quote:

---

In the overbased phenates, the extra calcium is believed to be incorprated as carbonate chains.

---

If you observe the structure of the phenate molecule on a molecular diagram, the above statement makes more sense and is consistent with chemical descriptions.

I agree, it probably should have been worded at a different level.

 

[MolaKule]

It is the job of the DISPERSANT

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=21;t=000032

to suspend deposits, disperse soot and deposit precursors, and to keep HC polymers from aggregating. Soot (HC particles) and resins from various polymers, such as VII's, are pushed together and congregated by the polar action of the dispersant molecule.

The dispersant forms "micelles" which congregate these particles and hold them in suspension. It is similar to raking leaves into one pile and then stuffing them into a bag.

Most dispersants are Alkylsuccinimides and alkylsuccinic esters (alkenyl succinimides), usually Polyisobutenyl succinate esters.

Most modern oils have good dispersants and much has been learned about dispersants through improved chemistry. It is the job of the DISPERSANT

http://theoildrop.server101.com/cgi/ultimatebb.cgi?ubb=get_topic;f=21;t=000032

to suspend suspend deposits, disperse soot and deposit precursors, and to keep HC polymers from aggregating. Soot (HC particles) and resins from various polymers, such as VII's, are pushed together and congregated by the polar action of the dispersant molecule.

The dispersant forms "micelles" which congregate these particles and hold them in suspension. It is similar to raking leaves into one pile and then stuffing them into a bag.

Most dispersants are Alkylsuccinimides and alkylsuccinic esters (alkenyl succinimides), usually Polyisobutenyl succinate esters.

Most modern oils have good dispersants and much has been learned about dispersants through improved chemistry. The amount of dispersant in motor oils is usually from 3% to 7% by weight, making it the highest among additives. In addition, the dispersant is the highest molecular weight component except for the viscosity improver.


Like any other component, the dispersant only has a certain lifetime, so oil drains or top offs replenish the dispersant.

Today, most of the dispersants for mineral oils are part of the Dispersant/VII package and are called "polymeric dispersants."

For full synthetics, the ester bases usually take on the job of dispersants.

[ December 03, 2004, 10:51 PM: Message edited by: MolaKule ]

 

[wileyE]

Are these the same detergent and dispersant additives that are used in two-cycle oils?

 

[MolaKule]

Not necesssarily.

The detergents used in 2-cycle oils have to be low-ash or no ash detergents which means they're purely organic.

The dispersants for 2-cycles are generally low residue dispersants.

 

[nortones2]

The invariably interesting, if "over my head" contribution Molakule. First question: is the dreaded VW/Toyota sludge a conglomeration of HC? Second question: (part A) does this mean the dispersants became geriatric, or (part B) were they lacking in the initial formulation?

No doubt there's a part C I've overlooked

 

[MolaKule]

All sludge is an aggregation of various hydrocarbons.

The dispersant and detergent have a useful life.

It is not so much they become geriatric as the fact they are used up surrounding and conglomerating sludge particles. I.E., they can only hold so much sludge in suspension.

 

[Shannow]

Molakule,
how does this sit with Nissan's requirements on their tubodiesels ?

They require a high detergent oil, but with low dispersents.

They state that it allows the sludge to be caught by the filter, rather than circulating the engine and wearing things out.

Thus they specify no better than CF-4.

 

[MolaKule]

Not sure I understand question.

To which Nissan document were you referring?

 

[Shannow]

Molakule,
it's in the owners manual to "never use CG-4", and in the engine service manual.

quote:

---

Engine Oils
Replacement lubricants for these new Diesel engines must meet the criteria set down by Nissan Motor Company Ltd. If a lubricant is used which does not meet the required standard, the New Vehicle Warranty will become conditional. This has been included in the Warranty Information and Maintenance booklet. The oil specification is as follows:
ZD30DDT engine API CF-4 (SAE 10W-30).
YD25DDTi engine API CF-4 (SAE 10W-30) ACEA 98-B1

Never use higher quality diesel oil than these, for example CG-4

The reason is for not using a higher quality is because of the new trends in USA for low PM (soot) engine designs (Japan concentrates on lowering NOx). These USA large diesel engines run with higher piston temperatures and require a lubricant which is designed top keep the PM in suspension. It can then be removed when the oil is replaced.

An additive which is called a “dispersant” is used to hold PM contaminants in suspension. The oil also has reduced detergent level. These changes make it difficult to trap the contaminants in the oil filter, which can increase the engine wear rate especially on the DOHC valve system.

As we have to use local oils, we require the very best in lubricant performance, especially because of the wide ranging conditions of use.

---

Nisan's service centres use PCMOs in these engines.

The oil companies specify top end (GRIII/IV) PCMOs for them also. To get a CF-4 rated diesel oil these days means GRI/II and 2% sulfated ash.

 

[1911]

quote:

---

Originally posted by MolaKule:
One of a "class" of most widely used additives are the Calcium and Magnesium Sulfonates, and phenates, made by the sulfonization or phenation of alkylbenzenes and base metals, and mixed with dispersed calcium carbonates. These same additives are also used to neutralize acids and prevent corrosion. The sulfonates in the additives surround sludge and other "wornout" hydrocarbons and sweep these "useless" molecules into little communities until drain time. The net effect is to "sweep-and-hold" noncontributing hydrocarbons.
What do we call this class of Additive?

---

Thanks Molakule,

The word on the street...aka "BITOG Boulevard" is that some of the new XOM oils like 5000 and 7500 are using sodium sulfonates. Do we have any reason to believe that these would not be as effective as Calcium and Magnesium Sulfonates and do you think these oils stillo have Calcium Sulfonates working with the Sodium sulfonates since they still have a serious calcium content? Also, do you think their decision may have been cost driven or based on technical reasons? THis is all way above my head.

Thanks,
1911

 

[MolaKule]

The new sodium alkylphenoxides (sodium alkyl salicilates) tend to have better thermal stability, and better friction reduction (11% less COF), so the sodium components are being used to synergistically aid in acid fighting and rust inhibition capabilities.

I am confident the decision to supplement with these sodium compounds was based on cost as well.

Another plus is their low reactivity with aluminum.