Acetylene with small hydrocarbon ions

D. Reaction of Acetylene with Other Small Hydrocarbon Ions.. ... 

The orientation of addition of iodine chloride to butadiyne, however, corresponds to an electrophilic attack. A study of the kinetics of bromination of various mono- and dialkyl-substituted butadiynes has been interpreted in terms of an electrophilic mechanism . The observed rates increased with increasing inductive electron-releasing power of the substituents. However, the effects are small, and under the conditions used (two-fold excess of hydrocarbon) it seems likely that significant polybromination occurred . Marked catalysis by bromide ion was observed and interpreted in terms of electrophilic attack by bromine on a complex of acetylene with Br ... 

---