QCD scattering processes with hard gluon emission

2 → 3 QCD scattering processes are studied in kinematical regions which are free from infrared and mass singularities. Anomalously large hard gluon emission corrections are found to gluon-gluon annihilation gg → q anti q. It is pointed out that in a kinematical region where azimuthal angle correlations of large transverse momentum π0,s have been measured at ISR, the 3-jet production rate is large and the contribution of the subprocess gq → ggq is greater than the contributions from quark-quark scattering qq → qqg. (orig.)