Tuesday, 28 April 2015

Petroleum distillates - What are they?

[:The word petroleum derived from the Latin ‘Petra’ and ‘Oleum’, literally means "rock oil" and refers to hydrocarbons that occur in sedimentary rocks of the Earth's crust]

Petroleum distillates is the term commonly used to refer to aliphatic hydrocarbons. Aliphatic hydrocarbons can actually be divided into two groups: petroleum distillates and synthetic paraffinic hydrocarbons. We use petroleum distillates to mean both types of products.

•Petroleum distillates include mineral spirits, kerosene, white spirits, naphtha, and Stoddard solvent. These products may contain trace amounts of benzene and other aromatics.
• When compared to petroleum distillates, the paraffinic hydrocarbons have lower flammability, lower aromatic content, narrower boiling range, and higher solvency. They are also more expensive than the petroleum distillates.
• The petroleum distillates (and paraffinic hydrocarbons) work well on hard-to clean organic soils such as heavy oil and ease, tar, and waxes.
• These products typically have low liquid surface tensions (22 to 28 dynes/cm).This allows them to penetrate and clean small spaces.
• Petroleum distillates typically operate at near room temperatures. This is due to the flammability of the products. However, the flash points may be higher than that of terpenes.
• Petroleum distillates are usually used in immersion baths.
• Ultra Sonic’s may or may not work, depending on the particular product.
• Petroleum distillates can typically handle high soil loads.
• When the cleaning power of the bath is exhausted, the entire bath usually needs to be replaced.
• Petroleum distillates are compatible with most materials including most elastomers. Mineral spirits may not be compatible with EPDM, SBR, and Silicone.
• Petroleum distillates are frequently used in manual wipe-down processes.
• Aliphatic hydrocarbons are often blends containing oxygenated hydrocarbons.

Flash points are higher than that of terpenes and traditional solvents. Lower flash points mean faster drying but more danger of burning.

Distillation is the basic process used to separate and purify the components of crude oil
Anyone making a blanket statement that products containing petroleum distillates (which include Silicone) are harmful has no real knowledge of petroleum refining. The advancement of this type of misinformation is usually meant to take advantage of the consumer's lack of knowledge in order to sell something that wouldn't sell otherwise, which reflects the seamier side of negative marketing / advertising.

Petroleum distillates, also called hydrocarbons or petrochemicals, refer to a broad range of compounds, thick natural oil obtained from beneath the earth, which are extracted by distillation during the refining of crude oil. During the fractional distillation of petroleum, crude oil is heated to (Catalytic cracking) allow various compounds to turn from liquid into vapour and then captured as they rise, cool, and condense.

Lighter, more volatile compounds rise higher before they condense and are collected on distillation trays. Heavier, less volatile compounds such as diesel fuel and oil are collected on lower distillation trays. Waxes and asphalts are collected from the bottom after the other products have volatilized.
Petroleum distillates are found in a wide variety of consumer-products including lip gloss, liquid gas, fertilizer, furniture polish, pesticides, plastics, paint thinners, solvents, motor oil, fuels and hundreds of other products. That a product contains petroleum distillates does not necessarily make that product harmful but it does depend upon which petroleum distillate is used and whither it has been further purified Petroleum distillates listed commonly on labels of general household products are those that distil off around naphtha’s. Petroleum jelly, a petroleum distillate product, is generally regarded as non-toxic.

Petroleum distillates contain both aromatic hydrocarbons (carbon rings) and aliphatic hydrocarbons (straight carbon chains). The chemical structure of the hydrocarbon largely defines the nature and behaviour of these compounds.

Distillates [: a substance that has been distilled to remove impurities] Distillation is the basic process used to separate and purify the components of crude oil; the distilled or purified portion of crude oil usually contains three general classes of compounds: Aromatic, Naphthenic and Paraffinic Hydrocarbons.

a) Aromatic hydrocarbons- [: the term 'aromatic' was assigned before the physical mechanism determining aromaticity was discovered, and was derived from the fact that many of the compounds have a sweet scent, the term aromatic in chemistry is no longer associated with aroma, and many aromatic compounds have no smell] are the most toxic compounds found in petroleum products, and include such substances as naphthalene, xylene, toluene, and benzene. 

Most aromatic hydrocarbons are long-term toxins and known cancer causing agents, they are great solvents and a base for many types of useful compounds. The configuration of six carbon atoms in aromatic compounds is known as a benzene ring, after the simplest possible such hydrocarbon, benzene. Aromatic hydrocarbons can be monocyclic or polycyclic. They are a perfect ingredient for making such things carburettor cleaner or a tar remover where strong solvency is needed.

b) Naphthenic hydrocarbons- (aka Cyclo paraffins) after further distillation aliphatic are used to make Naphthenic oil, a type of mineral oil. In contrast with paraffinic oils, naphthenic oils contain only low to no proportion of n-alkanes, being based on cycloalkanes (naphthenes) instead. The low-temperature behaviour of naphthenic oils is better than of paraffinic oils, making them suitable for applications that require low pour point. The degradation products of naphthenic oils are soluble in the oils, leading to fewer problems with formations of sludge’s and deposits. Naphthenic oils have different solvent properties than paraffinic oils. Naphthenic oils are characterized by high proportion of cyclic hydrocarbon fraction. The convention is that when the paraffinic carbon content is less than 55-60%, the oil is labelled as naphthenic.

The principal uses of naphthenic oils are as transformer oils, coolants, solvents, cutting fluids, and some lubricants, .light oils, solvents and even as a base for things like detergents and paint dryers and include methane, propane, and kerosene,

c) Aliphatic hydrocarbons - the simplest aliphatic compound is methane (CH4). Aliphatic include alkanes such as fatty acids and paraffin hydrocarbons, alkenes (such as ethylene) and alkynes (such as acetylene).In organic chemistry, compounds composed of carbon and hydrogen are divided into two classes: aromatic compounds, which contain benzene rings or similar rings of atoms, and aliphatic compounds (G. aleiphar, fat, oil), which do not contain aromatic rings. 

In aliphatic compounds, carbon atoms can be joined together in straight chains, branched chains, or non-aromatic rings (in which case they are called alicyclic). They can be joined by single bonds (alkanes), double bonds (alkenes), or triple bonds (alkynes). Besides hydrogen, other elements can be bound to the carbon chain, the most common being oxygen, nitrogen, sulphur, and chlorine. Most aliphatic compounds are flammable, allowing the use of hydrocarbons as fuel, such as methane in Bunsen burners, and acetylene in welding.

d) Paraffin [: the name is derived from the Latin parum (= barely) + affinis with the meaning here of "lacking affinity", or "lacking reactivity”] - the simplest paraffin molecule is that of methane, CH4, a gas at room temperature. Heavier members of the series, such as that of octane C8H18, appear as liquids at room temperature. The solid forms of paraffin, called paraffin wax, are from the heaviest molecules from C20H42 to C40H82. Paraffin wax was identified by Carl Reichenbach in 1830] paraffin compounds have much less solvency and usually are purified further. 

They are used in a myriad of consumer products, such as a coating for milk cartons and as ingredients in many lotions and skin creams. Crystal clear white oils are used as a laxative, to coat pans in bakeries and as a base for medicines. Paraffin wax refers to the solids with n=20–40. Paraffin compounds are perfect for use as a component in automotive waxes and polishes and those products used to treat painted surfaces, vinyl and plastic. Further purification produces Cyclo Paraffin and it is used in many pharmaceutical and skin beauty products, they are also used in car care waxes and polishes, they are used as a carrier system as they easily dissolve wax and provide spread ability and a lubricant for waxes, machine polishes and glazes.

e) Cyclo Paraffin - hydrocarbons are used in many car care products and perform many different and important functions. They are also used in many cleaning products as solvents to quickly emulsify oils, grease road tar and grime. They will not harm plastics, vinyl or rubber nor will they remove any important components like flex agents, plasticizers and etc., while it helps to clean and replace necessary oils to their surface. Waxes derived from petroleum are much easier to recover, and offer a wide range of physical properties that can often be tailored by refining processes.

Most producers offer two distinct types of petroleum waxes;

1. Paraffin- [:liquid paraffin has a number of names, including nujol, mineral spirits, adepsine oil, alboline, glymol, liquid paraffin, medicinal paraffin, saxol, or USP mineral oil] distinguished by large, well-formed crystals and micro-crystalline, higher melting waxes with small, irregular crystals. Some producers also sell "intermediate" wax, the boiling range cut where the transition in crystal size and structure occurs. Paraffin wax produced from petroleum is essentially a pure mixture of normal and iso-alkanes without the esters, acids, etc. found in the animal and vegetable-based waxes. A typical composition for mineral spirits: aliphatic solvent hexane having a maximum aromatic hydrocarbon content of 0.1% by volume, is listed as a potential carcinogen in the MSDS

2. Petroleum wax - producers also characterize wax by degree of refinement: fully refined paraffin has oil content generally less than 0.5%, and fully-refined micro-crystalline less than 1.5%; "slack wax" - precursors to the fully refined versions in either case would have oil content above 2% and as high as 35% by weight.

3. Ultra violet radiation (UVR) protection- The use of petroleum distillates allows premium ultra violet (UV) radiation absorbers to be included in the formulation (as an oil-in-water emulsion or by utilizing a resin as its carrier system) as the most effective ones are not soluble in water. This can provide excellent protection against deterioration, chalking and fading caused by sunlight for various plastics, rubber and vinyl dressings. It should be noted that the protection needs to be renewed periodically as it lessens over time.

Silicone (Siloxane) oils - are polymers that include silicon together with carbon, hydrogen, oxygen, and sometimes other chemical elements, which provide an excellent lubricant that when used as a carrier system in polishes and waxes that makes them easier to apply and remove When used in paints and other coatings it ensures an even flow through a spray nozzle ensuring an even product distribution. It not silicone that you need worry about, just the 'type' (what it’s formulated with) you need to be aware of. Silicone oils provide an excellent lubricant that when used as a carrier system in polishes and waxes that makes them easier to apply and remove When used in paints and other coatings it ensures an even flow through a spray nozzle ensuring an even product distribution.

Products that contain petroleum distillates must be labelled with the phrase, “Contains petroleum distillates”, regardless of the properties of the distillate used in its formulation. This labelling is mandated by the Consumer Product Safety Commission (a federal government agency) this warning is provided to help doctors and emergency personnel decide how best to treat in gestation. These warnings have nothing to do with product performance or suitability; the directions for use and other cautions are for information only

Information resource

1.        U.S. Environmental Protection Agency website
2.        EPA/Purdue University Study 2001
3.        American Association of Industrial Hygiene (AAIH)
4.        American Petroleum Institute (API) publications
5.        National Petrochemical & Refiners Association (NPRA)
6.        U.S. National Library of Medicine - http://householdproducts.nlm.nih.gov/index.htm

I would like to think that these articles become an asset to anyone who is new to detailing and to professionals alike, as well as industry experts who seek to advance their knowledge.

I hope the above article was informative. By having some understanding of the ‘What’ and ‘Why’ as well as the ‘How’ along with a little science to help you understand how the chemicals we use react, you can achieve the results you desire.

I would appreciate it if you would share this article as it helps other detailers further their knowledge. 

Questions and/ or constructive comments are always appreciated
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