1,4-Dibromobutane
[CAS# 110-52-1]

Identification

• Classification: Organic raw materials >> Hydrocarbon compounds and their derivatives >> Hydrocarbon halide
• Name: 1,4-Dibromobutane
• Molecular Formula: C₄H₈Br₂
• Molecular Weight: 215.91
• CAS Registry Number: 110-52-1
• EC Number: 203-775-5
• SMILES: C(CCBr)CBr

Properties

• Density: 1.8±0.1 g/cm³ Calc.^*, 1.808 g/mL (Expl.)
• Melting point: -20 °C (Expl.)
• Boiling point: 197.0 °C 760 mmHg (Calc.)^*, 216.6 - 219.4 °C (Expl.)
• Flash point: 65.2±17.7 °C (Calc.)^*, 110 °C (Expl.)
• Solubility: water immiscible (Expl.)
• Index of refraction: 1.508 (Calc.)^*, 1.519 (Expl.)

^* Calculated using Advanced Chemistry Development (ACD/Labs) Software.

Safety Data

• Hazard Symbols: GHS05;GHS06;GHS07 Danger
• Risk Statements: H301-H315-H318-H319-H335-H412
• Safety Statements: P261-P264-P264+P265-P270-P271-P273-P280-P301+P316-P302+P352-P304+P340-P305+P351+P338-P305+P354+P338-P317-P319-P321-P330-P332+P317-P337+P317-P362+P364-P403+P233-P405-P501

Hazard Classification

Hazard	Class	Category Code	Hazard Statement
Skin irritation	Skin Irrit.	2	H315
Serious eye damage	Eye Dam.	1	H318
Specific target organ toxicity - single exposure	STOT SE	3	H335
Acute toxicity	Acute Tox.	3	H301
Chronic hazardous to the aquatic environment	Aquatic Chronic	3	H412
Acute toxicity	Acute Tox.	4	H302
Skin sensitization	Skin Sens.	1	H317
Chronic hazardous to the aquatic environment	Aquatic Chronic	2	H411
Eye irritation	Eye Irrit.	2	H319
Acute toxicity	Acute Tox.	2	H330
Germ cell mutagenicity	Muta.	2	H341
Acute toxicity	Acute Tox.	3	H311

• Transport Information: UN 2810

Discovery and Applications

1,4-Dibromobutane is an organic compound belonging to the family of dihalogenated alkanes, specifically a dibromo derivative of butane with the molecular formula C₄H₈Br₂. It appears as a colorless to pale yellow liquid with a faint sweet odor and is only sparingly soluble in water but mixes readily with most organic solvents. The compound is characterized by bromine atoms at each end of a straight four-carbon chain, which makes it a highly reactive bifunctional alkylating agent. This symmetrical arrangement provides significant utility in organic synthesis, particularly in the preparation of cyclic compounds, polymers, and other intermediates that require a two-point attachment.

The compound was first studied in the context of halogenation reactions, where alkanes and alkenes could be converted into halogen derivatives through controlled substitution or addition processes. Laboratory-scale preparation of 1,4-dibromobutane typically involves the addition of bromine to 1,3-butadiene, followed by reduction of the resulting tetrabromo intermediate, or alternatively, the direct halogenation of 1,4-butanediol using hydrobromic acid. These methods highlight the versatility of bromination chemistry and its role in providing simple yet valuable building blocks for organic synthesis.

One of the most significant applications of 1,4-dibromobutane lies in its use as a bifunctional alkylating agent. Because each terminal carbon carries a bromine atom that can act as a leaving group, the compound undergoes substitution reactions at both ends. This allows it to form linkages between two nucleophilic groups, effectively serving as a chemical “bridge” in the synthesis of larger molecules. For example, treatment with ammonia or amines leads to the formation of diamines, which are useful precursors in polymer chemistry. Reaction with sulfur nucleophiles produces cyclic sulfides such as tetrahydrothiophene, a valuable heterocyclic compound employed in various fine chemical and pharmaceutical applications.

In the field of polymer chemistry, 1,4-dibromobutane has been utilized to prepare quaternary ammonium salts and crosslinked polymeric materials. Its bifunctionality makes it particularly suited for introducing structural units that improve mechanical stability and thermal resistance in polymer networks. Moreover, its reactivity has been exploited in the synthesis of ionic liquids and phase transfer catalysts, where the butylene chain provides an optimal spacer between functional groups.

Another important application involves the synthesis of macrocycles and heterocycles. Because of the linear four-carbon spacing between the reactive sites, 1,4-dibromobutane can be used to close rings of defined size when reacted with difunctional nucleophiles. This has proven useful in the preparation of crown ethers, cyclic amines, and sulfur-containing heterocycles, many of which are of interest for their ability to act as host molecules in supramolecular chemistry or as ligands in coordination complexes. The compound’s utility in ring-closing reactions has made it a standard reagent in laboratories investigating the synthesis of cyclic structures.

Mechanistically, the compound primarily undergoes bimolecular nucleophilic substitution (S_N2) reactions due to its primary carbon centers. Because there are two reactive ends, it is often employed in stepwise substitution processes to generate either linear extended molecules or cyclic products depending on the reaction design. This predictable reactivity makes it a common teaching example in organic chemistry for demonstrating the influence of chain length and bifunctionality on substitution outcomes.

Handling 1,4-dibromobutane requires caution, as it is classified as harmful and potentially hazardous to health. The compound is an irritant to skin, eyes, and mucous membranes, and inhalation of vapors may cause respiratory discomfort. Prolonged exposure has been associated with central nervous system effects. Like many brominated organics, it is also of environmental concern due to its persistence and toxicity to aquatic organisms. Appropriate safety measures include the use of protective gloves, safety glasses, fume hoods, and adherence to waste disposal regulations to prevent environmental release.

Over the decades, 1,4-dibromobutane has maintained its relevance as a versatile synthetic intermediate. Its role as a bridging reagent for linking functional groups, its ability to generate heterocycles, and its application in polymer chemistry ensure that it continues to be employed across academic, industrial, and applied research settings. Although it is not produced on the same scale as simpler alkyl bromides like 1-bromobutane, its bifunctionality gives it unique utility that makes it indispensable for specialized chemical synthesis.

References

2025. Ionic Liquid Synthesis. Topics in Catalysis, 68(2).
DOI: 10.1007/s11244-025-02122-y

2024. PROTAC Assembly. Medicinal Chemistry Research, 33(5).
DOI: 10.1007/s00044-024-03258-4

2024. Antihypoxic Properties. Russian Journal of Organic Chemistry, 60(9).
DOI: 10.1134/s1070428024090100