What Is a Hydroxyl?
The chemical formula of hydroxyl group is -OH, which is a common polar group. The hydroxyl group is mainly divided into alcohol hydroxyl group, phenol hydroxyl group, and the like.
- "Hydroxy" is a word invented by chemists, and was made by taking a part of the word "hydrogen" and "oxygen". read
- Hydroxyl groups can be divided into two groups: alcoholic hydroxyl groups and phenolic hydroxyl groups
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Hydroxyl chemical reaction
- 1. Reducing, can be oxidized to aldehyde or ketone or carboxylic acid.
- 2. Weak alkaline, phenolic hydroxyl group reacts with sodium hydroxide to form sodium phenolate. Although slightly acidic, many hydroxy-containing organic solutions are less acidic than water. Such as methanol (CH 3 OH), ethanol (CH 3 CH 2 OH) and so on.
- 3. Elimination reactions can occur, such as dehydration of ethanol to ethylene.
- 4. A substitution reaction can occur, and the alcoholic hydroxyl group reacts with sodium metal to replace the hydrogen atom in the hydroxyl group to generate hydrogen.
- 5. Substitution reaction can occur, dehydration between the molecules to form an ether (ROR ") R and R" are hydrocarbon groups.
Hydroxyl difference
- In many cases, since the hydroxyl and hydroxide are written the same in the illustrative formula, it is easy to be confused with hydroxide.
- Differences: 1. The number of electrons is different: the hydroxide is ten electrons, and the hydroxyl group is nine electrons; 2. The two electrons are different: the oxygen atom of hydroxide is surrounded by 8 electrons, and the oxygen atom of hydroxyl group is surrounded by 7 electrons .
- Although both hydroxide and hydroxyl groups are atomic groups, hydroxyl groups are functional groups and hydroxides are ions. In addition, hydroxide-containing substances are basic in aqueous solutions, while hydroxyl-containing substances are mostly acidic. The commonality between hydroxide and hydroxyl groups in organic chemistry is nucleophilicity.
Hydroxyl synthesis protection
- Hydroxyl group is one of the most common functional groups in organic chemistry. Both alcoholic and phenolic hydroxyl groups are easily oxidized by various oxidants. Therefore, in the synthesis of polyfunctional compounds, the hydroxyl group or part of the hydroxyl group needs to be protected first, preventing it from participating in the reaction, and then being converted in an appropriate step.