MolaKule
Staff member
Some time ago a member asked us to explain Complex Esters.
After reading
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=4;t=000056
this thread you know that esters are pure lubricants made from raw materials such as special alcohols and selected acids. When an alcohol and an acid are brought together with a catalyst, the temperature of the mixture goes up due to this being an exothermic or "giving-off-heat" reaction, and two main products are formed, the ester itself and some water. The mixture is then purged with nitrogen while heated further and by using vacuum stripping, the water is removed from the ester.
For machine lubrication, we know there are about 50 useful diesters and six times that many variations of polyolesters.
While some diesters have certain advantages, such as low pour points and seal swell, so do polyolesters, such as higher thermal stability and lower coefficient of friction, just to name a few.
Now one could mix these esters in various ratios to combine their advantages, but each ester's advantage/disadvantage might show up in the final mix.
What if you could get the best of both worlds in one ester?
Along comes complex esters.
Recall that for a polyolester such as TMP, we take an alcohol such as timethylpropane and react it with a acid, preferably a fatty acid such as heptanoic acid. For a polyolester such a pentaerylthritol ester (PE), we can take pentaerylthritol (alcohol) and react it with monoacid such as a valeric acid. If we also react the monoacid with an oleic acid, we obtain a polyoelate ester.
Recall that for a di-ester, we can take for example a 2-ethylhexanol (alcohol) and react it with sebasic acid and get 2-ethylhexyl sebacate, a seal swell additive.
Let's take Trimethylpropane (alcohol), 2-ethylhexanoic acid, Isopalmitic acid, heptane (an alcohol), and use Stannous octoate as the catalyst and put them into a flask.
After the reaction is complete, the flask is heated to approx. 250 C under vaccum and all water is literally removed from the mixture. Acid content is adjusted via calcium oxide resulting in a tbn of 0.03 to 0.5; a very neutral ester.
The resulting liquid, depending on the ratios of virgin components was approx. 3.2 cSt to 15 cSt, had a very light yellow tinge to it, and the resulting yield was 87%. Any solids that remained were filtered through very fine filters.
Result: an ester that has very low pour points, high VI's, seal swell properties close to mineral oils, excellent lubricity (low coefficient of friction, high film strength, High Temperature/High Shear), and excellent additive compatibility.
By adjusting processing parameters, as with PAO's, we can truly chemically engineer, through molecular modelling and design, just about any ester to perform as specified.
So what is the name of the resulting ester?
A polyolester
[ August 09, 2004, 06:25 PM: Message edited by: MolaKule ]
After reading
http://theoildrop.server101.com/ubb/ultimatebb.php?ubb=get_topic;f=4;t=000056
this thread you know that esters are pure lubricants made from raw materials such as special alcohols and selected acids. When an alcohol and an acid are brought together with a catalyst, the temperature of the mixture goes up due to this being an exothermic or "giving-off-heat" reaction, and two main products are formed, the ester itself and some water. The mixture is then purged with nitrogen while heated further and by using vacuum stripping, the water is removed from the ester.
For machine lubrication, we know there are about 50 useful diesters and six times that many variations of polyolesters.
While some diesters have certain advantages, such as low pour points and seal swell, so do polyolesters, such as higher thermal stability and lower coefficient of friction, just to name a few.
Now one could mix these esters in various ratios to combine their advantages, but each ester's advantage/disadvantage might show up in the final mix.
What if you could get the best of both worlds in one ester?
Along comes complex esters.
Recall that for a polyolester such as TMP, we take an alcohol such as timethylpropane and react it with a acid, preferably a fatty acid such as heptanoic acid. For a polyolester such a pentaerylthritol ester (PE), we can take pentaerylthritol (alcohol) and react it with monoacid such as a valeric acid. If we also react the monoacid with an oleic acid, we obtain a polyoelate ester.
Recall that for a di-ester, we can take for example a 2-ethylhexanol (alcohol) and react it with sebasic acid and get 2-ethylhexyl sebacate, a seal swell additive.
Let's take Trimethylpropane (alcohol), 2-ethylhexanoic acid, Isopalmitic acid, heptane (an alcohol), and use Stannous octoate as the catalyst and put them into a flask.
After the reaction is complete, the flask is heated to approx. 250 C under vaccum and all water is literally removed from the mixture. Acid content is adjusted via calcium oxide resulting in a tbn of 0.03 to 0.5; a very neutral ester.
The resulting liquid, depending on the ratios of virgin components was approx. 3.2 cSt to 15 cSt, had a very light yellow tinge to it, and the resulting yield was 87%. Any solids that remained were filtered through very fine filters.
Result: an ester that has very low pour points, high VI's, seal swell properties close to mineral oils, excellent lubricity (low coefficient of friction, high film strength, High Temperature/High Shear), and excellent additive compatibility.
By adjusting processing parameters, as with PAO's, we can truly chemically engineer, through molecular modelling and design, just about any ester to perform as specified.
So what is the name of the resulting ester?
A polyolester
[ August 09, 2004, 06:25 PM: Message edited by: MolaKule ]
