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Methyldibromoglutaronitrile
Methyldibromo glutaronitrile (MDBGN) is a widely used preservative. It is made by reacting bromine with 2-methyleneglutaronitrile below 30 °C. An allergy to the chemical can be discovered by performing a patch test. History and allergy In the mid-1980s, a maximum concentration of 0.1% in stay-on and rinse-off cosmetics was allowed. It was discovered soon afterwards that it caused allergic contact dermatitis to people with eczema. It has been in use since the 1990s as a preservative in skin care products such as lotions, wet wipes, shampoo, and liquid soaps. Industrial applications include its use in preserving oils, glues, and medical gels. In 2005, the EU banned its use in stay-on products, and in 2007 banned it in rinse-off products. In 2005–06, methyldibromoglutaronitrile/ phenoxyethanol was the ninth-most-prevalent allergen in patch test A patch test is a diagnostic method used to determine which specific substances cause allergic inflammation of a patient's sk ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Patch Test
A patch test is a diagnostic method used to determine which specific substances cause allergic inflammation of a patient's skin. Patch testing helps identify which substances may be causing a delayed-type allergic reaction in a patient and may identify allergens not identified by blood testing or skin prick testing. It is intended to produce a local allergic reaction on a small area of the patient's back, where the diluted chemicals were planted. The chemicals included in the patch test kit are the offenders in approximately 85–90 percent of contact allergic eczema and include chemicals present in metals (''e.g.'', nickel), rubber, leather, formaldehyde, lanolin, fragrance, toiletries, hair dyes, medicine, pharmaceutical items, food, drink, preservative, and other additives. Mechanism A patch test relies on the principle of a type IV hypersensitivity reaction. The first step in becoming allergic is sensitization. When skin is exposed to an allergen, the antigen-pre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Preservative
A preservative is a substance or a chemical that is added to products such as food products, beverages, pharmaceutical drugs, paints, biological samples, cosmetics, wood, and many other products to prevent decomposition by microbial growth or by undesirable chemical changes. In general, preservation is implemented in two modes, chemical and physical. Chemical preservation entails adding chemical compounds to the product. Physical preservation entails processes such as refrigeration or drying.Erich Lück and Gert-Wolfhard von Rymon Lipinski "Foods, 3. Food Additives" in ''Ullmann's Encyclopedia of Industrial Chemistry'', 2002, Wiley-VCH, Weinheim. Preservative food additives reduce the risk of foodborne infections, decrease microbial spoilage, and preserve fresh attributes and nutritional quality. Some physical techniques for food preservation include dehydration, UV-C radiation, freeze-drying, and refrigeration. Chemical preservation and physical preservation techniques ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bromine
Bromine is a chemical element; it has chemical symbol, symbol Br and atomic number 35. It is a volatile red-brown liquid at room temperature that evaporates readily to form a similarly coloured vapour. Its properties are intermediate between those of chlorine and iodine. Isolated independently by two chemists, Carl Jacob Löwig (in 1825) and Antoine Jérôme Balard (in 1826), its name was derived , referring to its sharp and pungent smell. Elemental bromine is very reactive and thus does not occur as a free element in nature. Instead, it can be isolated from colourless soluble crystalline mineral halide Ionic salt, salts analogous to table salt, a property it shares with the other halogens. While it is rather rare in the Earth's crust, the high solubility of the bromide ion (Br) has caused its Bromine cycle, accumulation in the oceans. Commercially the element is easily extracted from brine evaporation ponds, mostly in the United States and Israel. The mass of bromine in the oce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
2-Methyleneglutaronitrile
2-Methylene glutaronitrile is a Dimerization (chemistry), dimerization product of acrylonitrile and a starting material for Diamine, di- and triamines, for the biocide 2-Bromo-2-(bromomethyl)pentanedinitrile, 2-bromo-2-(bromomethyl)pentanedinitrile and for heterocycles, such as 3-cyanopyridine. Preparation 2-Methylene glutaronitrile is a side-product in the production of adiponitrile, hexanedinitrile which is used (after hydrogenation to 1,6-diaminohexane) as a key component for Engineering plastic, engineering polymers such as the polyamides (PA 66) or polyurethanes. Hexanedinitrile can be industrially produced by electrochemical hydrodimerisation or by catalytic dimerization of acrylonitrile. A catalytic tail-tail dimerization of two acrylonitrile molecules forms hexanedinitrile: Also head-to-tail dimerization can occur in the process. In the presence of tricyclohexylphosphine (PCy3) a yield of up to 77% 2-methylene glutaronitrile can be obtained: Metal halides (such as ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
