Detergent
From Wikipedia, the free encyclopedia
A detergent (as a noun) is a material intended to assist cleaning. The term is sometimes used to differentiate between soap and other surfactants used for cleaning. As an adjective pertaining to a substance, it (or "detersive") means "cleaning" or "having cleaning properties"; "detergency" indicates presence or degree of cleaning property.
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[edit] Composition
Detergents, especially those made for use with water, often include different components such as:
- Surfactants to 'cut' (dissolve) grease and to wet surfaces
- Abrasive to scour
- Substances to modify pH or to affect performance or stability of other ingredients, acids for descaling or caustics to break down organic compounds
- Water softeners to counteract the effect of "hardness" ions on other ingredients
- oxidants (oxidizers) for bleaching, disinfection, and breaking down organic compounds
- Non-surfactant materials that keep dirt in suspension
- Enzymes to digest proteins, fats, or carbohydrates in stains or to modify fabric feel
- Ingredients that modify the foaming properties of the cleaning surfactants, to either stabilize or counteract foam
- Ingredients that affect aesthetic properties of the item to be cleaned, or of the detergent itself before or during use, such as optical brighteners, fabric softeners, colors, perfumes, etc.
- Ingredients such as corrosion inhibitors to counteract damage to equipment with which the detergent is used
- Preservatives to prevent spoilage of other ingredients
- Washing agents may contain soap for the purpose of reducing foam rather than cleaning fabric.
Sometimes materials more complicated than mere mixtures of compounds are said to be detergent. For instance, certain foods such as celery are said to be detergent or detersive to teeth.
[edit] Types
There are several factors that dictate what compositions of detergent should be used, including the material to be cleaned, the apparatus to be used, and tolerance for and type of dirt. For instance, all of the following are used to clean glass. The sheer range of different detergents that can be used demonstrates the importance of context in the selection of an appropriate glass-cleaning agent:
- a chromic acid solution—to get glass very clean for certain precision-demanding purposes, namely in analytical chemistry
- a high-foaming mixture of surfactants with low skin irritation—for hand-washing of drink glasses in a sink or dishpan
- other surfactant-based compositions—for washing windows with a squeegee, followed by rinsing
- any of various non-foaming compositions—for glasses in a dishwashing machine
- an ammonia-containing solution—for cleaning windows with no additional dilution and no rinsing
- ethanol or methanol in Windshield washer fluid—used for a vehicle in motion, with no additional dilution
- glass contact lens cleaning solutions, which must clean and disinfect without leaving any eye-harming material that would not be easily rinsed off.
[edit] Terminology
Sometimes the word detergent is used to distinguish a cleaning agent from soap. During the early development of non-soap surfactants as commercial cleaning products, the term syndet, short for synthetic detergent was promoted to indicate the distinction, but never caught on very well and is incorrect, because most soap is itself synthesized (from glycerides). The term soapless soap also saw a brief vogue. There is no accurate term for detergents not made of soap other than soapless detergent or non-soap detergent.
Plain water, if used for cleaning, is a detergent. Probably the most widely-used detergents other than water are soaps or mixtures composed chiefly of soaps. However, not all soaps have significant detergency and, although the words "detergent" and "soap" are sometimes used interchangeably, not every detergent is a soap.
The term detergent is sometimes used to refer to any surfactant, even when it is not used for cleaning. This terminology should be avoided as long as the term surfactant itself is available.
[edit] History
The detergent effects of certain synthetic surfactants were noted in 1913 by A. Reychler, a Belgian chemist. The first commercially available detergent taking advantage of those observations was Nekal,[1] sold in Germany in 1917, to alleviate World War I soap shortages. Detergents were mainly used in industry until World War II. By then new developments and the later conversion of USA aviation fuel plants to produce tetrapropylene, used in household detergents, caused a fast growth of household use, in the late 1940s.[2] In the late 1960s biological detergents, containing enzymes, better suited to dissolved protein stains, as egg stains, were introduced in the USA by Procter & Gamble.[3]
[edit] See also
[edit] External links
[edit] References
- ^ Analytical Chemists job description, <http://www.123oye.com/job-descriptions/a/analytical-chemist.htm Analytical>. Retrieved on 2008-05-09
- ^ Spriggs, John (July 1975), An economical analysis of the developmente of substitutes with some illustrative examples and implications for the beef industry, Staff paper series, pp. 34-37, <http://ageconsearch.umn.edu/bitstream/123456789/22851/1/p75-14.pdf>. Retrieved on 2008-05-09
- ^ Roald, Arnvid S. & Nicolaas T. DE. Oude, "Granular enzyme-containing laundry composition", US 3451935, issued 1969-06-24
