In industry, methanethiol is prepared by the reaction of hydrogen sulfide with methanol. This method is employed for the industrial synthesis of methanethiol:
:CHOH + HS → CHSH + HO
Such reactions are conducted in the presence of acidic catalysts. The other principal route to thiols involves the addition of hydrogen sulfide to alkenes. Such reactions are usually conducted in the presence of an acid catalyst or UV light. Halide displacement, using the suitable organic halide and sodium hydrogen sulfide has also been used.
Another method entails the alkylation of sodium hydrosulfide.
: RX + NaSH → RSH + NaX(X = Cl, Br, I)
This method is used for the production of thioglycolic acid from chloroacetic acid.