1,4-Benzenebis(methanethiol) 1,4-Benzenedimethanethiol 1,4-Bis(mercaptomethyl)benzene 105-09-9 EINECS 203-269-4 NSC 72094 alpha,alpha'-p-Xylenedithiol p-Xylene-alpha,alpha'-dithiol p-Xylylenedithiol