5141. Isobutylene

Nomenclature

CAS number: 115-11-7
2-Methyl-1-propene; isobutene.
C4H8; mol wt 56.11.
C 85.62%, H 14.37%.

Description and references

Obtained from refinery streams by absorption on 65% H2SO4 at about 15°: Packie, Rupp, US 2424186, US 2509885; Draeger, US 2456260; Steele, Epps Jr., US 2497191 (1947, 1950, 1948, 1950, all to Standard Oil); Peters, Gothman; Edwards, Wesselhoft, US 2962537; US 3129265 (1960, 1964, both to Esso). Separation from a mixed C4 stream using 50% H2SO4: GB 824573, GB 858645 and FR 1337232 (1959, 1961 and 1963 to Compagnie Francaise de Raffinage); Valet et al., Hydrocarbon Process. Petr. Refin. 41, No. 5, 119 (1962); Martel, Chem. Eng. 72, No. 7, 66 (1965). Prepn: Verdol, US 3170000 (1965 to Sinclair). Review: Kennedy, Kirshenbaum, “Isobutylene” in Vinyl and Diene Monomers (part 2), E. C. Leonard, Ed. (Wiley-Interscience, New York, 1971) pp 691-756.

Chemical structure

Properties

Gas. bp760 6.900°; bp100 49.309°; bp30 67.90°; bp10 81.95°; bp1 105.06°. d420 0.5942; d425 0.5879; d430 0.5815. Practically insol in water. Very sol in alc, ether, sulfuric acid.

Caution

Simple asphyxiant.

Use

Primarily used to produce diisobutylene, trimers, butyl rubber, and other polymers; also to produce antioxidants for foods, packaging, food supplements, and for plastics: Hatch, Pet. Refin. 39, No. 6, 207 (1960).