Esters, General

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MolaKule

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Esters, in organic chemistry, are compounds formed (along with water), by the reaction of acids and alcohols. Because this process is analogous to the neutralization of an acid by a base in salt formation, esters were formerly called ethereal salts. This term is misleading because esters, unlike salts, are not ionized in solution (see acids and bases).

Esters can be formed from both organic and inorganic acids. For example, the simple ester ethyl nitrate may be obtained from ethyl alcohol and nitric acid (an inorganic acid), and the ester ethyl acetate may be obtained from ethyl alcohol and acetic acid (an organic acid). Another method of preparing esters is to employ not the acid itself but its chloride. For example, ethyl acetate may be prepared by the action of alcohol upon acetyl chloride, the chloride of acetic acid. Another important method of preparation is by the reaction of the silver salts of acids with an alkyl halide (usually iodine). For example, ethyl acetate may be prepared from silver acetate and ethyl iodide.

Esters are broken up by the action of water into their component acids and alcohols, a reaction greatly speeded by the presence of acids. For example, ethyl acetate is broken up into acetic acid and ethyl alcohol. The conversion of an acid into an ester is termed esterification. The reaction between an ester and a metallic base is known as saponification (see soap). When the decomposition of an ester occurs upon its reaction with water, the ester is said to be hydrolyzed.

The esters of organic acids are usually colorless, neutral liquids, pleasant-smelling and generally insoluble in water but readily soluble in organic solvents. Many esters have a fruity odor and are prepared synthetically in large quantities for commercial use as artificial fruit essences and other flavorings and as components of perfumes (see essential oils).

All natural fats and oils (other than mineral oils) and most waxes are mixtures of esters. For example, esters are the principal constituents of beef fat (tallow), hog fat (lard), fish oils (including cod-liver oil), and flaxseed oil (linseed oil). Esters of cetyl alcohol are found in the head oil of the sperm whale, and esters of myricyl alcohol in beeswax. Nitroglycerin, an important explosive, is an ester.

Esters such as amyl acetate (banana oil), ethyl acetate, and cyclohexanol acetate are the principal solvents for lacquer preparations. Other esters, such as dibutyl phthalate and tricresyl phosphate, are used as plasticizers in lacquers. Amyl acetate is employed as odor bait in grasshopper poisons, and several of the formates are good fumigants. Esters also have an important function in organic synthesis.
Esters have important medical uses. Ethyl nitrite is a diuretic and an antipyretic. Amyl nitrite is used in the treatment of asthma and epileptic convulsions as an antispasmodic. Nitroglycerin and amyl nitrite both cause blood-vessel dilation thereby lowering blood pressure. Ethyl chaulmoograte has been used in the treatment of leprosy. Dimethyl sulfate (often used in organic synthesis as a methylating agent) and diethyl sulfate are extremely dangerous in vapor form and must be handled cautiously.

Many additives are in the form of esters when added to the formulated oil, but carboxylic acid esters (and the sub-classes di-esters and polyol esters) are contained in fully formulated synthetic oils. Most Group III oils and PAO based oils need a small amount of ester for seal swell, increased detergency, better oxidative stability, greater VI, and increased additive solubility.

The two most common polyol esters for automotive applications are TMP (trimethylpropane) and DPE (DiPentaerythritol) PE (Pentaerythritol) or similar. Some di-esters are used in non-detergent compressor fluids, and NEO-Oil uses these as bases exclusively.

There are over 175 di-esters and over 250 polyol esters of last count.

A good overall description of esters for ester lubricating fluids can be found at:
http://www.hatcocorporation.com/pages/about_esters.html

Added: Carboxylic Acid Esters

Esters are created by a process called, "esterification," the reaction of alcohols or phenols with acids. For example, react tricresyl phosphate acid with an alcohol called n-butyl alcohol and the result is an ester product called "Neutra," a fuel system and crankcase cleaner.

A carboxylic acid is a general term for a number of acids with a specific molecular arrangement. A carboxylic ester can be made with one of over 120 carboxylic acids. Carboxylic acids may be used to form dibasic esters (as in NEO base oils)and polyol esters such as TMP and PE, which are used in Amsoil and Redline oils, respectively.

Hydroxyalkyl Carboxylic ester is actually a "lactone," a cyclic ester made from the salt of a hydroxy acid.

This ester is used in many motor oil formulations that contain PAO(s) and is used to increase the VI, cause a slight seal swell, adds miscibility (mixibility) for additives, increases oxidative stability, and acts as a Friction Modifier.

[ January 04, 2003, 12:37 AM: Message edited by: MolaKule ]
 
Wow, a one man organic chem data base. It takes me back to 1962, I guess I was not as asleep as I thought because a lot of that stuff sounds familiar. Keep up the good info. RW
 
Would you mind writing a bit about Esters and the role they play in Automobile oil formulations?

How about somthing about the new Esters Mobil has developed and something more on the the EOP Synthetic in the works by Pennzoil?

Molakule deserves a forum given Xmas gift,like a years worth of oil or something along that line
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I like Lubeguard products. They are primarily vegetable based esters. Their trans additive is good also but Auto-Rx does thesame thing at a lot lower cost at least here in Texas.

For a engine cleaning I would use Auto-RX for the bio based stuff.
 
Golly MoleKule, that's a LOT of information. I for one do not know what line of work or educational background you have, though reading between the lines I can make a few guesses (assuming that info isn't a copy & paste from a chemistry CD-ROM)
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So, what oil do you use in your engine? How often do you change it?
If I recall right, you like Auto-RX. Is that correct? When I have my RedLine drained (it was just put in so that could be a while) I'd like to have a good cleaning, should I use plain or synthetic oil? I'm thinking of just doing a 700 mile cleaning oil. Should the filter and by-pass filter be replaced just before that? If I have a by-pass filter, should I replace the element at the time the RedLine is drained, or after the Auto-RX 300 or 700 miles is up? (I want to have the used filter sent to the lab) If I have a by-pass, how important is the plain spin-on filter?

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Always plan at least 11 months into the future
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Only about 250 shopping days left before Christmas
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Rob
 
rob,

The information was drawn from my notes which was a compilation of research and lab work over the years.

On another thread I recently posted the oils I use, so you might want to do a search. I use some oils that are proprietary and are in development.

For your situation, I would continue to use Redline, and Auto-RX in the maintenance dosages and your engine should be clean. ARX does use some cleaning esters that are not contained in Redline.
 
that last paragraph looks as if the jounralist need a few more words but was unable to generate the correct information.

Unless you have severe blowby or weird fuel, the last paragraph is non sequitur.
 
No base oil, when at room temperature, has a smell. All base oils come from the refinery water white and clear.

Now when heated, mineral oils have this faint sulfur smell, PAO's no smell, and Esters have this "fatty" smell to them, because they are made of fatty acids and alcohols. The only esters that have "fruity" smells are those used in cosmetics and pharmaceuticals. Esters used in motor oils have little smell to them.

Additives and "odor-fiers" is what gives a formulated oil its smell.
 
I'm glad you mentioned this Mola because so many people were quick to denounce my comment that German Castrol was claimed to be a group 4 basestock (castrol's proclamation). The evidence that it HAD to be a ester was based simply on the smell.

It truly is the additives in the base fluid that give a oil its odor and color. Base oils that I've experimented with could pass for water before they get blended.
 
Esters oils are biodegradable by nature, but BIO oils are also esters based. Apparently the prefix Bio underlines a higher speed and a percentage of decomposition. What are type of esters usually used in Bio engine oils and what are their strong sides ? TYI.
 
Excellent point Primus.

Bio oils are indeed "natural" esters, which interest me very much as well, and presents an exciting way of weaning ourselves off petroleum-based feed stocks.

The term or prefix Bio or Bio-oil usually denotes an oil derived from living organisms, sch as plants or animals.

Some plant derived Bio-oils which may be used as lubricants are: {This list is NOT all inclusive since new bio-oils useful for lubrication are being discovered every day].

Peanut
Corn
Sesame
Soyabean
Walnut
Macadamia
Grapeseed
Sunflower
Canola (rapeseed)
Castor
Jojoba
Palm
Crambe
Coconut

BTW, canola is the term for genetically modified rape seed.
 
I worked for years in the paint industry using vegetable oils, including many of those listed in the above table. We used vegetable oils because the unsaturated ones, when exposed to air, would oxidize and convert to solid films. Heat and metals would accelerate this process. Try pouring a few drops of your wife's cooling oil on a hot manifold. Not in any engine of mine, ever.

I don't have a problem soy diesel. Diesel fuel remains fairly cool until injected into the combustion chamber, and usually is used up long before it could cause problems. For long term storage, I would recommend a flush with conventional alkane based fuel.
 
quote:

BTW, canola is the term for genetically modified rape seed.

Canola is the term for any of several varieties of the rape plant having seeds that contain less than 2% erucic acid.

http://www.yaelf.com/aueFAQ/mifcanola.shtml

The low erucic acid rape plants originated naturally, in Saskatchewan, from seeds grown by
a farmer who had immigrated from Poland.

http://www.canola-council.org/pubs/originhistory.pdf

The low erucic acid made the oil edible (erucic acid levels in edible rape is limited to 2%). From this seed two strains trademarked as "Canola" were developed between 1958 and 1974 by two Canadian scientists, Baldur Stefansson and Richard Downey. They are generally known as the "Polish" (Brassica rapa) and "Argentine" (Brassica napus) strains.
 
OK, lets add two more to the list:

Some plant derived Bio-oils which may be used as lubricants are: {This list is NOT all inclusive since new bio-oils useful for lubrication are being discovered every day].

Peanut
Corn
Sesame
Soyabean -
Walnut
Macadamia
Grapeseed
Sunflower
Canola (rapeseed)
Castor
Jojoba

Palm
Crambe
Coconut
Safflower - a variation of sunflower, part of the sunflower family. Not used very much because of its naturally high levels of oxidants and short shelf life.
Meadowfoam - a very promising oil, similar to Jojoba in terms of high levels of natural anti-oxidants.

BTW, most of the oils from the major plant groups are genetically modified (with respect to natural plant species) to yield high oleic (high in 'unsaturated' fatty acid) contents.

In this new list, I have bolded those oils I believe to be the major contenders for formulation purposes in automotive applications.
 
MoleKule said:react tricresyl phosphate acid with an alcohol called n-butyl alcohol and the result is an ester product called "Neutra," a fuel system and crankcase cleaner. You mean mixing these 2 chemicals and you get Neutra. Next is Lactone in both AMSOIL & NEO and finally which is the most expensive dibasic esters or Polyol esters. Thanks great stuff
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quote:

react tricresyl phosphate acid with an alcohol called n-butyl alcohol and the result is an ester product called "Neutra," a fuel system and crankcase cleaner. You mean mixing these 2 chemicals and you get Neutra.

Actually, you get something similar to Neutra; this was a simplified example. Neutra is actually cresyl acid (different acid) reacted with n-butyl alcohol. Reacted is the keyword here. Just mixing the two won't get you Neutra or any other ester. There has to a be a catalyst involved in the reaction as well.
 
I checked my bottle of Supercharger fluid. Ester(animal fat based) with some phospheric acid? I'll post a new topic with the actual bottle listings. Man that stuff stinks after use.
 
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