Search results
Results From The WOW.Com Content Network
Both the negatively charged anion HO −, called hydroxide, and the neutral radical HO·, known as the hydroxyl radical, consist of an unbonded hydroxy group. According to IUPAC definitions, the term hydroxyl refers to the hydroxyl radical (·OH) only, while the functional group −OH is called a hydroxy group. [1]
These derivatives commonly have other recommended names. For example, the name hydroxyl is recommended over oxidanyl for the –OH group. The name oxane is explicitly mentioned by the IUPAC as being unsuitable for this purpose, since it is already the name of a cyclic ether also known as tetrahydropyran. [3] [104]
As hygroscopic moisturizers, humectants work by attracting water to the upper layer of the skin (stratum corneum). [14] All humectants have common hydroxyl groups which allow them to participate in hydrogen bonding and attract water. This process attracts moisture from the outer layer of the skin or, in high humidity, from the atmosphere.
The rate of reaction with the hydroxyl radical often determines how long many pollutants last in the atmosphere, if they do not undergo photolysis or are rained out. For instance, methane, which reacts relatively slowly with hydroxyl radicals, has an average lifetime of >5 years and many CFCs have lifetimes of 50+ years.
The acidity of the hydroxyl group in phenols is commonly intermediate between that of aliphatic alcohols and carboxylic acids (their pK a is usually between 10 and 12). Deprotonation of a phenol forms a corresponding negative phenolate ion or phenoxide ion , and the corresponding salts are called phenolates or phenoxides ( aryloxides according ...
Owing to the presence of the polar OH alcohols are more water-soluble than simple hydrocarbons. Methanol, ethanol, and propanol are miscible in water. 1-Butanol, with a four-carbon chain, is moderately soluble. Because of hydrogen bonding, alcohols tend to have higher boiling points than comparable hydrocarbons and ethers.
The solubility in water of the other hydroxides in this group increases with increasing atomic number. [18] Magnesium hydroxide Mg(OH) 2 is a strong base (up to the limit of its solubility, which is very low in pure water), as are the hydroxides of the heavier alkaline earths: calcium hydroxide, strontium hydroxide, and barium hydroxide.
In chemistry, hydroxylation refers to the installation of a hydroxyl group (−OH) into an organic compound. Hydroxylations generate alcohols and phenols, which are very common functional groups. Hydroxylation confers some degree of water-solubility. Hydroxylation of a hydrocarbon is an oxidation, thus a step in degradation.