  We present experimental results obtained from photoionization and
photodissociation processes of abundant interstellar CH$_3$-X type organic
molecules like methanol (CH$_3$OH), methylamine (CH$_3$NH$_2$) and acetonitrile
(CH$_3$CN) as alternative route for the production of H$_3^+$ in interstellar
and star forming environments. The measurements were taken at the Brazilian
Synchrotron Light Laboratory (LNLS), employing soft X-ray photons with energies
between 200 and 310 eV and time of flight mass spectrometry. Mass spectra were
obtained using the photoelectron-photoion coincidence techniques. Absolute
averaged cross sections for H$_3^+$ production by soft X-rays were determined.
We have found that, among the channels leading to molecular dissociation, the
H$_3^+$ yield could reach values up to 0.7% for single photoionization process
and up to 4% for process involving double photoionization. The H$_3^+$
photoproduction cross section due to the dissociation of the studied organic
molecules by photons over the C1s edge (200-310 eV) were about 0.2-1.4 $\times$
10$^{-18}$ cm$^2$. Adopting the typical X-ray luminosity $L_X \gtrsim 10^{31}$
erg s$^{-1}$ which best fit the observational data for AFGL 2591 (Stauber et
al. 2005) we derive an estimative for the H$_3^+$ photoproduction rate due to
methyl-compounds dissociation process. The highest value for the H$_3^+$ column
density from methanol dissociation by soft X-rays, assuming a steady state
scenario, was about $10^{11}$ cm$^2$, which gives the fraction of the
photoproduced H$_3^+$ of about 0.05%, as in the case of dense molecular cloud
AFGL 2591. Despite the extreme small value, this represent a new and
alternative source of H$_3^+$ into dense molecular clouds and it is not been
considered as yet in interstellar chemistry models.
