2-Bromochlorobenzene-d4
[CAS 1219795-51-3]

Identification

• Classification: Chemical reagent >> Deuterated reagent
• Name: 2-Bromochlorobenzene-d4
• Synonyms: 1-bromo-2-chloro-3,4,5,6-tetradeuteriobenzene
• Molecular Formula: C₆D₄BrCl
• Molecular Weight: 195.48
• CAS Registry Number: 1219795-51-3
• SMILES: [2H]C1=C(C(=C(C(=C1[2H])Cl)Br)[2H])[2H]

Properties

• Density: 1.6$+/-$0.1 g/cm³ Calc.^*
• Boiling point: 203.4$+/-$13.0 $degree$C 760 mmHg (Calc.)^*
• Flash point: 79.4 $degree$C (Calc.)^*
• Index of refraction: 1.575 (Calc.)^*

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

Safety Data

• Hazard Symbols: GHS07 Warning
• Risk Statements: H302-H315-H319-H335
• Safety Statements: P280-P305+P351+P338

Discovery and Applications

2-Bromochlorobenzene-d₄ is a deuterium-labeled halogenated aromatic compound derived from bromochlorobenzene in which four hydrogen atoms on the benzene ring are replaced by deuterium. The molecule belongs to the class of halogenated benzenes and is used primarily in analytical chemistry and research applications rather than in large-scale industrial processes. Isotopically labeled aromatic halides such as 2-bromochlorobenzene-d₄ are important because they combine the chemical behavior of the parent compound with the ability to be selectively detected and quantified using mass spectrometry.

The development of deuterated aromatic compounds is closely tied to the expansion of isotope chemistry during the twentieth century. As analytical instrumentation advanced, particularly gas chromatography and mass spectrometry, the need for stable isotope-labeled standards increased. Deuterium was widely adopted because it is chemically similar to hydrogen but produces a measurable mass shift, allowing labeled compounds to be distinguished from unlabeled analogs without significantly altering their chemical behavior. This made deuterated halogenated benzenes useful tools in analytical method development.

2-Bromochlorobenzene itself is a disubstituted benzene containing both bromine and chlorine atoms on the aromatic ring. These halogen substituents strongly influence the electronic properties of the benzene system through inductive electron-withdrawing effects and increase the compound’s stability toward electrophilic substitution. The deuterated analog retains these structural features while replacing selected hydrogen atoms with deuterium, typically on positions not occupied by halogens.

The primary application of 2-bromochlorobenzene-d₄ is as an internal standard in quantitative analytical chemistry. Internal standards are compounds added in known amounts to samples in order to improve the accuracy and precision of analytical measurements. Because isotopically labeled compounds closely mimic the behavior of their unlabeled counterparts during sample preparation, extraction, and instrumental analysis, they are particularly valuable in gas chromatography-mass spectrometry workflows. The mass difference introduced by deuterium allows the labeled compound to be distinguished and measured independently from the analyte.

This compound has also been used in environmental and chemical analysis studies involving halogenated aromatic compounds. Brominated and chlorinated benzenes are of interest due to their persistence and occurrence in industrial contexts. Deuterated analogs such as 2-bromochlorobenzene-d₄ are used to validate analytical methods, assess recovery efficiency, and ensure accurate quantification in complex environmental matrices. These applications are essential in studies involving trace-level detection of halogenated organic pollutants.

Another documented use is in method development for chromatographic separation techniques. Because isotopically labeled compounds behave nearly identically to their non-labeled counterparts, they are ideal for evaluating instrument performance, retention behavior, and detection sensitivity. The presence of both bromine and chlorine in the molecule also produces characteristic isotope patterns in mass spectrometry, which can aid in instrument calibration and spectral interpretation.

The compound is additionally relevant in research involving isotope effects and molecular behavior. Although deuterium substitution does not significantly change the overall chemical identity of aromatic systems, it can provide insight into reaction mechanisms and kinetic isotope effects in certain experimental contexts. Studies using deuterated aromatic halides contribute to a broader understanding of how isotopic substitution influences chemical processes.

From a physicochemical perspective, 2-bromochlorobenzene-d₄ is expected to exhibit properties very similar to those of the non-deuterated parent compound, including hydrophobicity and volatility characteristics typical of halogenated aromatic hydrocarbons. The primary difference arises in mass and spectroscopic behavior, which enables its use as a labeled tracer compound.

Overall, 2-bromochlorobenzene-d₄ is a stable isotope-labeled aromatic halide used primarily as an analytical reference standard. Its value lies in its ability to provide accurate quantification and reliable calibration in chromatographic and mass spectrometric analysis, particularly in studies involving halogenated aromatic compounds in environmental and chemical research contexts.