  We discuss production of nonphotonic electrons in proton-proton scattering at
RHIC. The distributions in rapidity and transverse momentum of charm and bottom
quarks/antiquarks are calculated in the $k_t$-factorization approach. We use
different unintegrated gluon distributions from the literature. The
hadronization of heavy quarks is done by means of Peterson and Braaten et al.
fragmentation functions. The semileptonic decay functions are found by fitting
recent semileptonic data obtained by the CLEO and BABAR collaborations. We get
good description of the data at large transverse momenta of electrons and find
a missing strength concentrated at small transverse momenta of electrons.
Plausible missing mechanisms are discussed.
