Hydrocarbons, C3 – C4 - Analysis of impurities in 1-butene

Significance of the Topic

The analysis of trace C3–C4 hydrocarbons in 1-butene is critical for petrochemical quality control and downstream processing. Accurate impurity profiling ensures product purity, informs reactor feed decisions, and protects catalyst performance in polymerization and other industrial applications.

Objectives and Study Overview

This application study demonstrates a rapid gas chromatography method for separating and quantifying six C3–C4 impurities—propane, isobutane, n-butane, trans-2-butene, isobutene, and cis-2-butene—in 1-butene. The goal is to achieve baseline resolution within a 13-minute run time, covering a concentration range of 5–1000 ppm.

Methodology

An Agilent CP-Al2O3/Na2SO4 capillary column (0.32 mm × 50 m, 5 μm film) was employed in a split injection configuration. The column temperature was held at 110 °C, with nitrogen carrier gas at 110 kPa. The injector temperature was 150 °C with a 20 mL/min split flow, and detection was achieved by flame ionization (FID) at 200 °C. A 100 μL sample volume enabled detection across the low-ppm range.

Used Instrumentation

• GC-capillary system (Agilent Technologies)
• Column: CP-Al2O3/Na2SO4, 0.32×50 m, df=5 μm
• Carrier gas: Nitrogen, 110 kPa
• Injector: Split, 20 mL/min at 150 °C
• Detector: FID at 200 °C

Main Results and Discussion

The method achieved baseline separation of all seven peaks—including the 1-butene analyte—in under 13 minutes. Detector response was linear from 5 to 1000 ppm, with excellent repeatability. The inert alumina/sulfate column provided selectivity for saturated and unsaturated C3–C4 hydrocarbons, enabling clear resolution of isomeric butenes.

Benefits and Practical Applications

• Fast turnaround for routine quality control in refining and polymer-grade 1-butene production
• High sensitivity and linearity across a broad concentration range
• Robust separation of isomeric impurities without derivatization
• Easy integration into existing GC-FID workflows

Future Trends and Potential Applications

Emerging developments include coupling of this separation with mass spectrometry for structural confirmation and trace-level quantitation. Advances in micro-column technology and faster thermal cycling could reduce analysis times further. Method adaptation for online process monitoring and real-time quality assurance is also a promising direction.

Conclusion

The Agilent CP-Al2O3/Na2SO4 column method provides a robust, rapid, and sensitive solution for profiling C3–C4 impurities in 1-butene. Its reliable performance and ease of use make it well suited for industrial and research laboratories focused on petrochemical analysis.

Reference

This summary is based on Agilent Technologies application note A00592 (2011).