C4h9br properties reactions applications
Butyl bromide
of halogenated hydrocarbons is a compound formed after the hydrogen atom in the hydrocarbon molecule is replaced by a halogen atom. Today, butyl bromide ($C_4H_9Br $) is used to describe its properties, reactions and applications.
Properties
Butyl bromide has four isomers, namely n-butyl bromide (1-bromobutane), sec-butyl bromide (2-bromobutane), isobutyl bromide (1-bromo-2-methylpropane) and tert-butyl bromide (2-bromo-2-methylpropane). Its appearance is mostly colorless to light yellow liquid with a special odor. The density is greater than water, insoluble in water, soluble in organic solvents such as ethanol and ether. The boiling point varies with isomers and is roughly within a certain temperature range. The boiling point of n-butyl bromide is about 101.6 ° C, the boiling point of sec-butyl bromide is about 91.2 ° C, the boiling point of isobutyl bromide is about 91.5 ° C, and the boiling point of tert-butyl bromide is about 73.3 ° C.
reaction
1. ** nucleophilic substitution reaction **
The halogen atom of butyl bromide has high activity and is easily replaced by nucleophilic reagents. Take the reaction with sodium hydroxide aqueous solution as an example to generate corresponding alcohols. If n-butyl bromide is co-heated with sodium hydroxide aqueous solution, the bromine atom is replaced by hydroxyl group to form n-butanol and sodium bromide, the reaction formula is: $C_4H_9Br + NaOH\ xrightarrow {\ Delta} C_4H_9OH + NaBr $. If reacted with sodium cyanide ethanol solution, the bromine atom is replaced by cyanide to form nitriles, such as n-butyl bromide and sodium cyanide to obtain pentonitrile, the reaction formula is: $C_4H_9Br + NaCN\ xrightarrow {ethanol} C_4H_9CN + NaBr $, this reaction can grow the carbon chain.
2. ** Elimination reaction **
Under the action of strong alkali alcohol solution, butyl bromide can eliminate reaction, debromide hydrogen to form olefins. If tert-butyl bromide is heated in potassium hydroxide alcohol solution, the elimination reaction occurs to form 2-methyl-1-propene with potassium bromide and water. The reaction formula is: $C_4H_9Br + KOH\ xrightarrow {alcohol,\ Delta} C_4H_8 + KBr + H_2O $. When butyl bromide with different structures undergoes elimination reactions, it follows the Zaitsev rule, that is, it mainly generates olefins with more hydrocarbon groups attached to double-bonded carbon atoms.
Apply
1. ** Organic synthesis intermediates **
Butyl bromide is widely used in the field of organic synthesis. It can prepare various alcohols, nitriles, olefins and other compounds through the above-mentioned reactions such as nucleophilic substitution and elimination. It provides important starting materials for the construction of complex organic molecules. For example, in the pharmaceutical industry, it can be used to synthesize the precursor of drug molecules with specific structures.
2. ** Solvent **
Because butyl bromide has good solubility to many organic compounds and a moderate boiling point, it can be used as a solvent in some organic reaction systems to promote uniform reaction and improve reaction efficiency.
3. ** Preparation of surfactant **
After a series of chemical reactions, butyl bromide can participate in the preparation of surfactant. The hydrocarbon group in its structure imparts lipophilic properties to the surfactant, and a hydrophilic group is introduced after derivatization, so that the prepared surfactant has both hydrophilic and lipophilic properties, and is used in daily chemical, textile and other industries.
