1,4-Butanediamine, N,N'-diethyl- 19435-68-8 EINECS 243-064-7 N,N'-Diethyl-1,4-butanediamine N,N'-Diethylbutane-1,4-diamine N,N'-Diethylbutylenediamine N,N'-Diethyltetramethylenediamine NSC 166327