The base used in the original research paper is ammonia and the solvent is water or an alcohol.
[1][2] He suggested the following process on his way to diphenylbutadiyne: In the related Eglinton reaction two terminal alkynes are coupled by a copper(II) salt such as cupric acetate.
The stoichiometry is represented by this highly simplified scheme:[4] Such reactions proceed via copper(I)-alkyne complexes.
It relies on the TMEDA complex of copper(I) chloride to activate the terminal alkyne.
[8] In 1882 Adolf von Baeyer used the method to prepare 1,4-bis(2-nitrophenyl)butadiyne, en route to indigo dye.