Process for the production of sulfur containing silanes by the following steps (a) preparing an aqueous phase preparation by mixing sodium hydrosulfide or sodium sulfide, sulfur, Na 2 CO 3 and/or NaOH and a brine of step (f) and optionally of aqueous suspension of step (h), (b) adding 20 - 100 wt.-% of the total amount of phase transfer catalyst (c) continuously or in portions adding halogen alkyl silane, and simultaneously adding the rest of the total amount of phase transfer catalyst, in portions or continuously, (d) optionally adding brine from (f), optionally adding aqueous suspension from (h), optionally adding solid residue from step (k), separate the phase into a lower aqueous suspension and an upper organic phase and draw off the organic phase, (e) supply of the aqueous suspension from (d), optionally adding aqueous suspension from (h), separate in a salt cake and brine, (f) recycle all or a part of the brine of step (e) into step (a) and optional into step (d), (g) optionally distillate the rest of the brine from step (e) to yield aqueous distillate and aqueous suspension, (h) optionally recycle the aqueous suspension of step (g) into step (a) and /or (d) and/or (e), (i) route the organic phase of step (d) to an evaporation step to yield a organic residue and low boiling distillate, (j) separate the organic residue from the evaporation step (i) into a sulfur containing silane and a solid residue, (k) optionally the solid residue of step (j) is recycled to step (d). (a) preparing an aqueous phase preparation by mixing sodium hydrosulfide or sodium sulfide, sulfur, Na 2 CO 3 and/or NaOH and a brine of step (f) and optionally of aqueous suspension of step (h), (b) adding 20 - 100 wt.-% of the total amount of phase transfer catalyst (c) continuously or in portions adding halogen alkyl silane, and simultaneously adding the rest of the total amount of phase transfer catalyst, in portions or continuously, (d) optionally adding brine from (f), optionally adding aqueous suspension from (h), optionally adding solid residue from step (k), separate the phase into a lower aqueous suspension and an upper organic phase and draw off the organic phase, optionally adding aqueous suspension from (h), optionally adding solid residue from step (k), separate the phase into a lower aqueous suspension and an upper organic phase and draw off the organic phase, (e) supply of the aqueous suspension from (d), optionally adding aqueous suspension from (h), separate in a salt cake and brine, optionally adding aqueous suspension from (h), separate in a salt cake and brine, (f) recycle all or a part of the brine of step (e) into step (a) and optional into step (d), (g) optionally distillate the rest of the brine from step (e) to yield aqueous distillate and aqueous suspension, (h) optionally recycle the aqueous suspension of step (g) into step (a) and /or (d) and/or (e), (i) route the organic phase of step (d) to an evaporation step to yield a organic residue and low boiling distillate, (j) separate the organic residue from the evaporation step (i) into a sulfur containing silane and a solid residue, (k) optionally the solid residue of step (j) is recycled to step (d). <EOS>