(E)-But-2-ene 2-BUTENE, (E)- 2-Butene, (2E)- 2-Butene-trans 2-trans-Butene 624-64-6 EINECS 210-855-3 HSDB 5723 Low-boiling butene-2 beta-trans-Butylene trans-1,2-Dimethylethylene trans-2-Butene trans-Butene