K X-ray production cross sections, photopeak energy shifts and I(Kβ)/I(Kα) intensity ratios are measured for ¹²C projectiles, in the 14 to 50 MeV bombarding energy range, on several elements (Al, Si, S, Cl, K, Ca, Ti, Cr, Fe, and Cu), using high resolution Si(Li) X-ray spectroscopy. A comparison is made with calculated ECPSSR cross-section values corrected by multiple ionization of K, L and M target subshells and electron capture into the partially empty K-shell of the projectile. The main application for these measurements is multielement trace analysis through PIXE (Particle Induced X-ray Emission).