It has been fractionated through a Todd column (p 11, Model A with ~60 plates) under atmospheric pressure and the purity can be checked by gas chromatography. Stabilize it with 0.5% of 2,6-di-tert-butyl-p-cresol. It has IR with at 3100 + 2870 (CH2), 1780 (C=O), 1640 (C=C) and 940 (CH2out-of-plane) and 910 (CH2 wagging) cm-1. [IR: Lee J Org Chem 30 3943 1965, Levaillant Ann Chim (Paris) 6 504 1936.] It is used for protecting NH2 groups in peptide synthesis [Olofson et al. Tetrahedron Lett 1563 1977]. [Beilstein 3 III 28.]