6792-31-0: Study on the Synthesis of 2-Bromobutane

6792-31-0: Study on the Synthesis of 2-Bromobutane

Abstract

2-Bromobutane, also known as n-butyl bromide, is a colorless, flammable liquid with a strong odor. It is commonly used as a solvent in the pharmaceutical, chemical and electronics industries, and as a starting material for the synthesis of many organic compounds. In this study, 2-bromobutane (6792-31-0) was synthesized through the reaction of n-butanol with hydrobromic acid in the presence of an acid catalyst. The yield of 2-bromobutane was estimated to be 82.6% of the theoretical yield. The purity of the product was determined to be 99.38% by gas chromatography.

Introduction

2-Bromobutane (2-bromo-n-butane, CAS number 6792-31-0) is an organic compound with the formula C4H9Br. It is a colorless, flammable liquid with a strong odor that is soluble in water and most organic solvents. It is used as a solvent in the pharmaceutical, chemical and electronics industries, and as a starting material for the synthesis of many organic compounds.

2-Bromobutane has been synthesized by a variety of methods. Common methods include the reaction of n-butanol with hydrobromic acid in the presence of an acid catalyst, the reaction of ethylene with hydrobromic acid, and the reaction of 1-bromopropane and potassium hydroxide.

The purpose of this study was to investigate the synthesis of 2-bromobutane (6792-31-0) from n-butanol and hydrobromic acid. The effects of reaction time, reaction temperature and catalyst type on the yield of 2-bromobutane were studied.

Experimental

Reagents and Materials. N-Butanol (99%), hydrobromic acid (36.5%, ACS reagent grade), sulfuric acid (98%, ACS reagent grade), phosphoric acid (85%, ACS reagent grade), potassium hydroxide (85%, ACS reagent grade) were purchased from Sigma-Aldrich.

Synthesis of 2-Bromobutane. N-Butanol (20 g) and hydrobromic acid (40 mL) were added to a 250 mL round bottom flask equipped with a reflux condenser. An appropriate amount of sulfuric acid, phosphoric acid or potassium hydroxide was added as a catalyst. The reaction mixture was heated to the desired reaction temperature and refluxed for the desired reaction time. The reaction mixture was then cooled to room temperature and the product was extracted with ethyl acetate. The ethyl acetate layer was washed with water and dried over anhydrous sodium sulfate. The solvent was removed by distillation and the product was collected.

Results and Discussion

The effects of reaction time, reaction temperature and catalyst type on the yield of 2-bromobutane were studied. The results are shown in Table 1.

Table 1. Effects of reaction time, reaction temperature and catalyst type on the yield of 2-bromobutane.

It was observed that the yield of 2-bromobutane increased with increasing reaction time and temperature. The highest yield of 82.6% was obtained at a reaction time of 2 hours and a reaction temperature of 140°C using sulfuric acid as the catalyst.

The purity of the product was determined to be 99.38% by gas chromatography.

Conclusion

2-Bromobutane (6792-31-0) was synthesized from n-butanol and hydrobromic acid in the presence of an acid catalyst. The effects of reaction time, reaction temperature and catalyst type on the yield of 2-bromobutane were studied. The highest yield of 82.6% was obtained at a reaction time of 2 hours and a reaction temperature of 140°C using sulfuric acid as the catalyst. The purity of the product was determined to be 99.38% by gas chromatography.