Organic chemistry / by Frank C. Whitmore.

  • Frank C. Whitmore
Date:
1937
Catalogue details

Licence: In copyright

Credit: Organic chemistry / by Frank C. Whitmore. Source: Wellcome Collection.

    65/1104 page 49
    is then converted to the dibromide which is treated with a second mol of Grignard reagent. Zinc then gives the olefin. V. MeEtC = CMe2, b. 91° has been made from the tertiary alcohol. Octylenes, C8Hi6. Only about one third of the 66 possible structural isomers have been prepared. The two diisobutylenes, b. 101.2° and 104.5° (p. 42), are the best known octylenes. Their hydrogenation gives 2,2,4-Me3- pentane (“iso-octane”), the anti-knock standard used with n-heptane in rating gasolines (p. 26). HC1 and HBr add readily to give 2,2,4-Me3-4-halogen-pentanes. Chlorine and bromine give unsaturated halides instead of the dihalides. Oxidation of mixed diisobutylenes with dichromate and acid gives a fair yield of methyl neopentyl ketone, MeCOCH2CMe3. Two of the more difficultly obtainable octylenes, 3,3-Me2- hexene-4, b. 106°, and 2,2-Me2-hexene-3, b. 100.1°, have been made by the xanthate reaction (Schurman 1933). The highly branched octylenes, unsym.-diisopropylethylene, b. 103°; 2,3,4-Me3-pentene-2, b. 115°; 2,2,3-Me3-pentene-3, b. 112°; and 2,3,3-Me3-pentene-l, b. 108° have been made by dehydration of the corresponding tertiary alcohols (Whitmore 1932). Higher olefins can be made by heating the palmitic or stearic esters of the higher alcohols under suitably diminished pressure (Krafft 1883). Higher normal olefins, cetene (Ci6), cerotene (C26) and melene (C30) have been made from cetyl alcohol, Chinese wax and beeswax respectively. Cetene has been used as a standard for Diesel fuel. In this type of engine it gives no “knock” (p. 12). It has now been replaced by the more stable cetane. Mixed higher alkenes obtained by cracking a petroleum rich in alkanes have been polymerized to give an artificial lubricating oil (Syntholube). Olefin mixtures obtained by cracking processes can be con- verted to special resins. Determination of the Structure of Olefins. This is best done by the action of ozone to give ozonides. This process is little understood. The decomposition of the ozonides (often danger-
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