Phosphine is a precursor to many organophosphorus compounds. It reacts with formaldehyde in the presence of hydrogen chloride to give tetrakis(hydroxymethyl)phosphonium chloride, which is used in textiles.  The hydrophosphination of alkenes is versatile route to a variety of phosphines. For example, in the presence of basic catalysts  adds of Michael acceptors.  Thus with acrylonitrile, it reacts to give tris(cyanoethyl)phosphine:
Acid catalysis is applicable to hydrophosphination with isobutylene and related analogues:
where R is , alkyl, etc.