RBr + NaSH to RSH + NaBr

@neutral condition, there should be no H2S around, I think!

Do not acidify your reaction mixture to create H2S, then may be it should be ok.

Thanks, Guobing. The reaction is performed under a mixture of EtOH/THF. So it will not be a problem to generate H2S?

Do you think if I use NaSH hydrate will somehow affect the reaction? I do not have anhydrous NaSH.

I do not know whether NaSH will dissolve in EtOH/THF well or not?

Water should not be an issue, -SH is much stronger nucleophile than H2O, even much stronger than -OH, I believe. Add water may accelerate the reaction due to better solubility of NaSH.

I don't know will it sute in your case but standart industrial absorbent for H2S is water solution of 2-aminoethanol which is regenerated by heating at 120 C.

You can connect bubbler to reaction mixture with solution of NaOH, generated H2S gas will react with NaOH

H2S is toxic but I have never came across ( or experienced) that its explosive . Could be trapped in an alkali or best in a ferrous sulfate solution (suitable for small scale). Both are effective

I would not use NaSH. Instead I would do a reaction using Thiourea. In my experience synthesizing thiols, thiourea is much better reactive than NaSH. The reactions are clean and give high yields. For more information see: Speziale, A. J. (1963). "Ethanedithiol". Organic Syntheses; Collective Volume, 4, p. 401. or Eccles et al, ARKIVOC 2010 (ix) 216-228.

I check with Mr.: Guobing Xiang at first, then the extraction is done using an appropriate organic solvent with the addition of strong acid