2-Butanone, 4,4'-thiobis- 2-Butanone, 4,4'-thiodi- 4,4'-Thiobis(2-butanone) 4,4'-Thiodi(2-butanone) 40790-04-3 5-Thianona-2,8-dione Di(butan-3-one-1-yl) sulfide FEMA No. 3335 NSC 42865