The hydroxide of an alkali metal or an alkaline earth metal is reacted with sulfur at 220 deg c and 320 psig to form a solution of the desired hydrosulfide. Thus, an aqueous solution of naoh and sulfur was reacted at 220 deg c and 320 psig. The distribution of the soluble forms of sulfur was hs- 40.8, S2o32- 44.0, So42- 1.1, So32- 1.3, and sx2- 12.8 pct and >99 pct of the sulfur was dissolved. When the reaction temperature was 90 deg c in an open vessel the respective values were 15.6, 50.1, 0.1, 0.6, 33.6, And >99 pct.
U.S. Pat. 4,156,656; May 29, 1979; Chem. Abstr. 90:189,266P