Analysis of Trace Hydrocarbon Impurities in 1,3-Butadiene Using Rt®-Alumina BOND/MAPD Columns

Identifying and quantifying trace hydrocarbon impurities in 1,3-butadiene is critical in producing high quality synthetic rubber products. Standard analytical methods employ alumina PLOT columns which yield good resolution for low molecular weight compounds, but suffer from irreproducibility and poor sensitivity for more polar hydrocarbon impurities, like propadiene, acetylene, and methyl acetylene. New Rt®-Alumina BOND/MAPD PLOT columns feature a unique deactivation that improves response level and predictability for diene and acetylene hydrocarbons. In addition, these columns have a higher maximum temperature (up to 250°C) which extends the application range. Here, we demonstrate the utility of these columns for analyzing trace polar hydrocarbon impurities in 1,3-butadiene.

1,3-butadiene is typically isolated from products of the naphtha steam cracking process.

Prior to purification, 1,3-butadiene can be contaminated with significant amounts of isobutylene as well as other C4 isomers. In addition to removing these C4 isomeric contaminants during purification, it is also important that 1,3-butadiene be free of propadiene and methyl acetylene, which can interfere with catalytic polymerization. Alumina PLOT columns are the most commonly used GC column for this application; however, the determination of polar hydrocarbon impurities at trace levels can be quite challenging and is highly dependent on the deactivation of the alumina surface. Restek has recently developed a new line of alumina columns with a unique, high-performance deactivation. These columns—the Rt®-Alumina BOND/MAPD (fused silica) and MXT®-Alumina BOND/MAPD (metal) columns—are ideal for the analysis of polar hydrocarbons such as acetylene, methyl acetylene, and propadiene, and also perform well for generic light hydrocarbon analysis.