diol
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Definition
- Noun:
- Any of a class of alcohols having 2 hydroxyl groups in each molecule: A "diol" is a specific type of organic chemical compound. It belongs to the broader class of alcohols but is defined by the presence of exactly two hydroxyl (-OH) groups attached to its molecular structure.
Usage and Examples
- Noun:
- Ethylene glycol, a common antifreeze, is a well-known diol.
- The synthesis of certain polymers requires the use of a diol as a starting material.
- Chemists study the properties of various diols for industrial applications.
Advanced Usage and Scientific Context
- "Vicinal diol": A diol where the two hydroxyl groups are attached to adjacent carbon atoms.
- The reaction with osmium tetroxide typically forms a vicinal diol from an alkene.
- "Geminal diol": A diol where the two hydroxyl groups are attached to the same carbon atom.
- Geminal diols are often unstable and readily lose water to form carbonyl compounds.
Variants and Related Words
- Glycol: This is a common synonym, especially for simple aliphatic diols like ethylene glycol.
- Propylene glycol is a diol used in food and pharmaceutical products.
- Polyol: A more general term for alcohols containing multiple hydroxyl groups (more than two).
- Glycerol, with three -OH groups, is a polyol, not a simple diol.
Synonyms
- Glycol: Often used interchangeably, particularly for low-molecular-weight diols.
- Bivalent alcohol: An older, less common term emphasizing the two reactive sites.
Notes on Meaning
- The term "diol" is exclusively used in scientific contexts, particularly in chemistry and biochemistry. It is not used in everyday language.
- The defining feature is the number of hydroxyl groups. A molecule with one -OH group is a simple alcohol (like ethanol), with two is a diol, and with three or more is generally a polyol.
Noun
- any of a class of alcohols having 2 hydroxyl groups in each molecule