Prepn by reduction of crotonaldehyde: Nystrom, Brown, J. Am. Chem. Soc. 69, 1197 (1947); Olivier, Young, ibid. 81, 5811 (1959); Smith, Holm, US 2761883; Finch, Furman, US 2763696 (both 1956 to Shell); Foreman, US 3109865 (1963 to Standard Oil Co., Ohio). Prepn of (E) and (Z)-forms: Hatch, Nesbitt, J. Am. Chem. Soc. 72, 727 (1950); Hiskey et al., J. Org. Chem. 21, 429 (1956); of (Z)-form only: Clarke, Crombie, Chem. Ind. (London) 1957, 143. Toxicity study: H. F. Smyth et al., Am. Ind. Hyg. Assoc. J. 23, 95 (1962).