Beschreibung:
<jats:title>Abstract</jats:title><jats:p>The structure of isoprene oligomers synthesized by cationic oligomerization in the presence of the BF<jats:sub>3</jats:sub> · H<jats:sub>2</jats:sub>O complex as an initiator in a hexane solution at 40°C was investigated. These oligomer fractions obtained with the degree of polymerization (DP) in the range 5‐12, and the completely hydrogenated oligomers were examined using the direct inlet system‐mass spectrometry (DIS‐MS) technique. The distribution of the cyclic and linear structures in the oligomers was obtained by integrating the selected ion current of the different hydrogenated products. The results obtained were interpreted by means of a statistical simulation based on a step‐by‐step competition between cyclization and monomer addition reaction. The value of the probability of cyclization was found to be very high for low‐molecular‐weight oligomers and to decrease with increasing molecular weight of the oligomers.</jats:p>