White spirit, also known as Stoddard solvent, is a paraffin-derived clear, transparent liquid which is a common organic solvent used in painting and decorating. In chemistry paraffin is the common name for the Alkane Hydrocarbons with the general formula C n H2 n +2 A solvent is a liquid or gas that dissolves a solid liquid or gaseous Solute, resulting in a Solution. In 1924, an Atlanta dry cleaner named W. Dry cleaning is any cleaning process for Clothing and Textiles using an organic Solvent rather than Water. J. Stoddard worked with Lloyd E. Jackson of the Mellon Research Institute to develop specifications for a less volatile dry cleaning solvent as an alternative to more volatile petroleum solvents. Dry cleaners began using it in 1928 and it was the predominant dry cleaning solvent in the United States from the late 1920s until the late 1950s.
It is a mixture of saturated aliphatic and alicyclic C7 to C12 hydrocarbons with a maximum content of 25% of C7 to C12 alkyl aromatic hydrocarbons. In Organic chemistry, compounds composed of Carbon and Hydrogen are divided into two classes Aromatic compounds which contain Benzene rings An alicyclic compound is an Organic compound that is both Aliphatic and cyclic In Organic chemistry, a hydrocarbon is an Organic compound consisting entirely of Hydrogen and Carbon. An alkyl is a Univalent radical consisting of Carbon and Hydrogen atoms arranged in a chain
White spirit is used as an extraction solvent, as a cleaning solvent, as a degreasing solvent and as a solvent in aerosols, paints, wood preservatives, lacquers, varnishes, and asphalt products. Aerosol spray is a type of dispensing system which creates an aerosol mist of liquid particles Paint is any Liquid, liquifiable or mastic composition which after application to a substrate in a thin layer is converted to an opaque Solid In a general sense lacquer is a clear or coloured Varnish, that dries by solvent evaporation and often a curing process as well that produces a hard durable finish in any Varnish is a transparent, hard protective finish or film primarily used in Wood finishing but also for other materials Asphalt ( is a sticky black and highly viscous liquid or semi-solid that is present in most crude Petroleums and in some natural deposits sometimes termed asphaltum In western Europe about 60% of the total white spirit consumption is used in paints, lacquers and varnishes. White spirit is the most widely used solvent in the paint industry. In households, white spirit is commonly used to clean paint brushes after decorating. Its paint thinning properties enable brushes to be properly cleaned (by preventing the paint from hardening and ruining the bristles) and therefore enabling them to be re-used.
Three different types and three different grades of white spirit exist. The type refers to whether the solvent has been subjected to hydrodesulfurization (removal of sulfur) alone (type 1), solvent extraction (type 2) or hydrogenation (type 3). Hydrodesulfurization (HDS is a Catalytic chemical process widely used to remove Sulfur (S from Natural gas and from refined petroleum products Hydrogenation is the Chemical reaction that results in addition of Hydrogen (H2 Each type comprises three different grades: low flash grade, regular grade, and high flash grade. The grade is determined by the crude oil used as the starting material and the conditions of distillation. Petroleum ( L petroleum, from Greek πετρέλαιον, lit
In addition there is type 0, which is defined as distillation fraction with no further treatment, consisting predominantly of saturated C9 to C12 hydrocarbons with a boiling range of 140-200 °C.
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Physical properties
The physical properties of the three types of white spirit are:
| Property | T1: Low flash | T2: Regular | T3: High flash |
|---|---|---|---|
| Initial boiling point (IBP) (°C) | 130-144 | 145-174 | 175-200 |
| Final boiling point (°C) | IBP+21, max. The boiling point of a liquid is the temperature at which the Vapor pressure of the liquid equals the environmental pressure surrounding the liquid 220 | ||
| Average relative molecular mass | 140 | 150 | 160 |
| Relative density (15 °C) | 0. The molecular mass (abbreviated m of a substance, more commonly referred to as molecular weight and abbreviated as MW, is the Mass of one Relative density, sometimes called specific density, is the Ratio of the Density of a substance to the density of a given reference material 765 | 0. 780 | 0. 795 |
| Flash point (°C) | 21-30 | 31-54 | > 55 |
| Vapour pressure (kPa, 20 °C) | 1. The flash point of a flammable liquid is the lowest Temperature at which it can form an ignitable mixture in air Vapor pressure (also known as equilibrium vapor pressure or saturation vapor pressure) is the Pressure of a Vapor in equilibrium 4 | 0. 6 | 0. 1 |
| Volatility (n-butyl acetate=1) | 0. 47 | 0. 15 | 0. 04 |
| Autoignition temperature (°C) | 240 | 240 | 230 |
| Explosion limits (Flammable Range) (% by volume in air) | 0. The autoignition temperature or kindling point of a substance is the lowest temperature at which it will spontaneously ignite in a normal atmosphere without an external 6 - 6. 5 | 0. 6 - 6. 5 | 0. 6 - 8 |
| Vapour density (air=1) | 4. Vapour density is the Density of a Vapour in relation to that of Hydrogen. 5-5 | 4. 5-5 | 4. 5-5 |
| Refractive index (at 20 °C) | 1. The refractive index (or index of Refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves is reduced inside the medium 41-1. 44 | 1. 41-1. 44 | 1. 41-1. 44 |
| Viscosity (cps, 25 °C) | 0. Viscosity is a measure of the resistance of a Fluid which is being deformed by either Shear stress or Extensional stress. 74-1. 65 | 0. 74-1. 65 | 0. 74-1. 65 |
| Solubility (% by weight in water) | < 0. Solubility is the characteristic Physical property referring to the ability of a given substance the Solute, to dissolve in a Solvent. 1 | < 0. 1 | < 0. 1 |
| Kauri-butanol value | 29-33 | 29-33 | 29-33 |
| Aniline point (°C) | 60-75 | 60-75 | 60-75 |
| Reactivity | reaction with strong oxidizing agents | ||
| Odour threshold (mg/m3) | - | 0. The Kauri-butanol value ("Kb value" is an international standardized measure of Solvent power for a Hydrocarbon solvent and is governed by an ASTM Aniline point is defined as the temperature at which equal volumes of Aniline and Diesel oil are completely Miscible. 5-5 | 4 |
Toxicity
White spirit is mainly classed as an Irritant.
White spirit has a fairly low acute toxicity by inhalation of the vapour, dermal (touching the skin) and oral routes (ingestion). However, acute exposure can lead to central nervous system depression resulting in lack of coordination and slowed reactions. Exposure to very high concentrations in enclosed spaces can lead to general narcotic effects (drowsiness, dizziness, nausea etc. The term narcotic (ναρκωτικός is believed to have been coined by the Greek physician Galen to refer to agents that benumb or deaden causing loss . . ) and can eventually lead to unconsciousness. Oral ingestion presents a high aspiration hazard. Prolonged or repeated skin exposure over a long period of time can result in severe irritant dermatitis, also called contact dermatitis. Dermatitis is a Blanket term meaning any " Inflammation of the skin" (e Contact dermatitis is a term for a Skin reaction resulting from exposure to Allergens (allergic contact dermatitis or irritants (irritant contact dermatitis It is highly recommended that skin exposure is kept to a minimum by use of gloves and that hands are washed after coming into contact with it. Occasional exposure to skin is highly unlikely to cause any problems.
Exposure to an average white spirit concentration of 240 mg/m3(40 ppm) for more than 13 years could lead to chronic Central nervous system effects. In Vertebrates the central nervous system ( CNS) is the part of the Nervous system which is enclosed in the Meninges. White spirit is implicated in the development of "chronic toxic encephalopathy" among house painters. Encephalopathy /ɛnˌsɛfəˈlɒpəθi/ literally means Disease of the Brain.
Owing to the volatility and low bioavailability of its constituents, white spirit, although it is moderately toxic to aquatic organisms, is unlikely to present significant hazards to the environment. It should not however, be purposely poured down the sink or freshwater drain if avoidable. It should be disposed of correctly wherever possible.
See also
References
- World Health Organisation safety sheet
- Chemicals Used In Drycleaning Operations - Environmental Enlightenment
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