Esters, General

MolaKule

Staff member
Thread starter
Messages
21,597
Location
Iowegia - USA
quote:
is there a simple test that can be carried out to see if esters are present ?
I have no knowledge of simple test that could carried out by a non-chemist.
 
Messages
33,974
Location
Southern NJ
quote:
There are over 175 di-esters and over 250 polyol esters of last count
Amazing. So these oil formulators have a lot to chose from. It must be a task in and of itself in trying to pick the best choices. I mean look at Redline/Old Diester Amsoil/Motul and Delvac 1. They all used different esters and show different results. And then you have the additives interacting with all of this. Very cool. Chemistry is very interesting. [Cool]
 

MolaKule

Staff member
Thread starter
Messages
21,597
Location
Iowegia - USA
The relative molecular mass (sometimes called "Molecular Weight") is the ratio of the average mass per molecule of an element or compound TO 1/12 the mass of a carbon-12 atom. I.E., it is equal to the SUM of relative atomic masses of ALL atoms that comprise a molecule. Generally speaking, the higher molecular weight products of an oil show higher viscosities, but that only half of the story since the molecular "structure" also affects the molecular weight. Take the VII molecules of polymthylacrylates. These are high molecular weight structures that cause the formulated oil to become more viscous as temperature rises because of uncoiling at higher temperatures. Ester may contain high or low molecular weight components as well, and may have KV's of 2 cST to over 100 cSt at 100 C. In esters, the structures are more important than molecular weight (except of course in determining final base viscosity). When developing esters, particular attention is paid to ester structure. Short linear chains show better oxidative stability, whereas increasing the acid chain length of the molecule improves (decreases) the coefficient of friction. This why Di- and Pentaerithyritol esters (PE's) are better (more stable) than Trimethylpropane (TMP) esters, and why TMP is better than Neopentylglycol (NPG) esters. The PE's have short chains of linear acid chains with make the ester more oxidatively stable and exhibit lower coefficients of friction. If the ester is made from linear branched acids, the ester has higher flash points; increasing the molecular weight (making the ester molecule more compact) will also increase the flash point. Representative esters: Phthalates - Used mainly in air compressors; short fat molecule results in VI v.s pour point tradeoff. Trimellitates - Short, branched esters that have high flash points and low volatilities and good thermal stability. Used when you need to leave a soft film behind. Dimerates - Made from the acid of tallow oils and an alcohol (is three-branched); Has excellent lubricity and thermal and oxidative stability; used mainly in 2-stroke oils. Polyols - SPE's, PE's, TMP's, TME's, and NPG's. Three or more shortchain but fat molecules. Polyols are generally more oxidative and thermally stable by 50 C over diesters and 150 C over petroleum oils. These esters have lower coefficients of friction than either diesters or PAO's. By adding a polyol ester at least 5-10% to a PAO or mineral oil reduces base oil friction remarkably. So esters are natural Friction Modifiers. Advanced esters can also BE USED AS VII improvers. Unlike long-chain polymers (such as methacrylates), complex polyols do NOT EXHIBIT the temporary loss of viscosity under forces exterted by shear, as in gears. Because complex esters are shorter chain molecules, they tend not to shear into smaller molecules. Adding amine "backbones" to ester molecules allows them to have better antioxidant capabilities.
 
Messages
211
Location
UK
Molakule: I have heard that esters have polar properties, whereas PAO and other lubricants have nil or small polarity. Is this correct? Further, are such properties, if they exist, uniform throughout the ester group?
 

MolaKule

Staff member
Thread starter
Messages
21,597
Location
Iowegia - USA
All fluid materials have polar properties, some more than others. From Most Polar (attractied to Metal) to least: Esters Mineral Oils PAO's. The majority of esters are very polar due their molecular nature.
 

MolaKule

Staff member
Thread starter
Messages
21,597
Location
Iowegia - USA
Here are some very useful esters used in motor oils and gear lubes: 1. PHOSPHORODITHIOIC ACID, O,ODI- C1-14-ALKYL ESTERS, ZINC SALTS 68649-42-3 Also known as ZDDP 2. 2-ETHYLHEXYL SEBACATE 122-62-3 Used as a seal swell agent, base oil, and friction modifier.
 

MolaKule

Staff member
Thread starter
Messages
21,597
Location
Iowegia - USA
Here's another useful multifunctional ester: 1. PHOSPHORODITHIOIC ACID, O,OBIS( 2-ETHYLHEXYL) ESTER, MOLYBDENUM COMPLEX 72030-25-2 Soluble Moly complex, AW/EP and antioxidant
 
Messages
1,859
Location
USA
Originally Posted By: nucleardawg
You mentioned Jojoba in the list of esters. Since it was posted on tonight I do believe that the Lubegard Bio Tech Engine Ptotectant is using that in it's formulation.
Hy-per Lube uses jojoba in their racing oil supplement formula which from what I have read on their site that the only difference from the regular oil supplement they sell is the jojoba oil in it. Lots of great information MolaKule, as always. Have you been able to or would you test any of the new G Oil? It is made out of tallow, as I am sure you know.
 
Messages
818
Location
Tacoma, WA
Originally Posted By: ac_tc
Ok.. So now we now that esters belongs in oil. Should i dope my HDEO ci+4 oil with lets say 20% redline?
The effect is not linear - 5 to 10% is a useful and not too expensive addition. As the percentage goes up, the marginal utility decreases. Also, Red Line is a blend. In addition you can formulate a completely successful motor oil with no esters - you could use, for example, an alkylated napthlene to get many of the same benefits.
 
Top