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Saturday, 18 October 2014

Advantages of Synthetic Base Oils.

Some advantages of synthetic base oils you should know.

Although base stock oils are mineral, semi-synthetic, synthetic or vegetable based, the advantages of synthetic base oils are becoming more pronounced. Until the late 1990s most motor oils were mineral based but since then synthetic base oils have become more widely available at more affordable prices.

Classification gives clues as to the advantages of synthetic base oils.

Mineral oils fall into the main blends as categorised in the table below:

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Although improvements in blending of the base oils have reduced some of the problems that were typical of crude based lubricants in the 1960s and 1970s there are still several advantages of synthetic base oils. Depending on the level of refining, mineral oils can still suffer from inconsistent molecular sizing, weak unsaturated bonds and impurities such as Sulphur and Aromatics that lead to shorter oil service life, poor film strength, and low Viscosity Indices. Depending on the level of refinement the price will determine the quality of the base stock used in mineral based oils.

Highly cracked (Hydro cracked) mineral based Synthetics are derived by a different refining process which offers better performance owing to the consistent molecular structure and purity.

A variety of advantages of synthetic base oils from different processes.

Synthetic Base Stocks – (Often referred to as Group III, IV &V) – these Base Stocks require a chemically modified base that can be of a petroleum or chemical origin.

Group III – these are Base Oils that have been converted by means of a catalytic process in the presence of Hydrogen, usually under greater pressures. These resulting Base Oils are very pure and refined with superior performance to Group I and II Base Stocks.

Although API Group III base oils are sometimes considered Fully synthetic, they are still classified as high-level mineral-base stocks. A Synthetic or Synthesized material is one that is produced by combining or building individual units into a unified entry. Synthetic base stocks as described above are man-made and tailored to have a controlled molecular structure with predictable properties, unlike mineral base oils, which are complex mixtures of naturally occurring hydrocarbons and paraffins.

PAO (Polyalphaolefin) (Group IV) – These lubricants are 100% Synthetic chemical compounds. Specific types of olefins (organic) are used as base stock oils in some synthetic lubricants. Poly-alpha-olefin (or poly-α-olefin, abbreviated as PAO), is a polymer made by polymerizing an alpha-olefin. An alpha-olefin (or α-olefin) is an alkene where the carbon-carbon double bond starts at the α-carbon atom, i.e. the double bond is between the #1 and #2 carbons in the molecule.

Synthetic Esters (Group V) – API Group V Esters are 100% Synthetic chemical compounds consisting of a carbonyl adjacent to an ether linkage. They are derived by reacting an oxoacid with a hydroxyl compound such as an alcohol or phenol. Esters are usually derived from an inorganic acid or organic acid in which at least one -OH (hydroxyl) group is replaced by an -O-alkyl (alkoxy) group, and most commonly from carboxylic acids and alcohols. That is, esters are formed by condensing an acid with an alcohol.

Many chemically different "esters", because of their excellent lubricity, are used as either "additives" or "base stocks" for lubricants.

Bio-Based Oils (Group V / unclassified) – Derived from renewable resources which are readily biodegradable. Some of these renewable sources include: Sugar, Algae Succinic Acid add to the advantages of synthetic base oils. 

What are the advantages of synthetic base oils over crude based lubricants.

Petroleum-based mineral oils function very well as lubricants in probably 90 percent of industrial applications. They are cost-effective and provide a reasonable service life if used properly but have some limitations, depending upon the specific type of base stock used, the refining technology, the type and level of additives blended, and the operating conditions encountered. The main service difficulties within mineral oils are:
  1. The presence of waxes, which can result in poor flow properties at low temperature. 
  2. Poor oxidation stability at continuously high temperatures, which can lead to sludge and acid buildup.
  3. The significant change in viscosity as the temperature changes, which can cause the base oil to thin excessively at high temperature. 
  4. A practical maximum high-temperature application limit of about 125 degrees C (250 degrees F) above which the base oil oxidizes very rapidly. It is desired to keep mineral oil-based lubricants within the operating range of 40 to 65 degrees C (100 to 150 degrees F). 
Synthetic base oils are expensive because of the processing involved in creating these pure chemical base oils. However the advantages of synthetic base oils often offer a financial benefit to using them.

With regard to their chemical purity, mineral oils contain thousands, if not millions, of different chemical structures (molecules): In a synthetic oil every structure in the synthetic oil is almost identical to the structure beside it. The advantages of synthetic base oils are their ability to outperform mineral oils at high operating temperatures and at low operating temperatures. There are other potential advantages, too.

Depending on the type of synthetic, other advantages of synthetic lubricants (beyond the high- and low-temperature advantage) may include:
  • Superior wear control 
  • Superior friction control 
  • Superior aging characteristics 
  • Superior film strength 
  • Superior detergency levels 
  • Better low- and high-temperature viscosity performance at extreme service temperatures 
  • Better (higher) Viscosity Index (VI) 
  • Better chemical and shear stability 
  • Decreased evaporative loss 
  • Resistance to oxidation, thermal breakdown, and oil sludge problems 
  • Extended drain intervals, with the environmental benefit of less used oil waste generated 
  • Better lubrication during cold starts 
  • Extended engine life 
  • In engine hot spot areas (in particular in turbochargers and superchargers) the advantages of synthetic base oils include superior protection against "ash" and other deposit formation resulting in less oil burnoff and reduced oil passageway clogging 
  • Reduced frictional losses leading to icreased horsepower and torque due to less initial drag on engine
  • Improved Fuel Economy - from 1.8% to up to 5% has been documented in fleet tests 
  • Cleaner engine surfaces 
  • Fire resistance (phosphate esters)

Despite the advantages of synthetic base oils there are the downsides.

Although the advantages of synthetic base oils are numerous synthetic lubricants can cost as much as 3 times the cost of mineral derived oils. However, other issues often given as negatives of synthetic lubrications such as seal compatibility and additive solvency can be controlled through careful selection.

Issues such as viscosity often quoted as a reason for not being suitable in a classic car will depend on the selection of the correct oil. Unfortunately in the classic car community synthetics receive bad press for all the wrong reasons, whereas the advantages of synthetic base oils are often played down.

To ensure you maximise the advantages of synthetic base oils it’s important that you choose only high quality full synthetic lubricants., from reputable manufacturers. Habot Oil is a high quality synthetic oil producer that can supply high quality synthetic lubricants for most applications. Call the professionals at Habot Oil for information on how we can reduce costs and improve efficiencies.