| 摘要 |
A hydrocarbon mixture consisting substantially or completely of C3-C5 normal and/or iso-alkanes is rendered odourless by a process comprising contacting the hydrocarbons in the liquid state with concentrated H2SO4, separating the hydrocarbon and acid phases, and then distilling the former. The acid may be of 80-95% by weight concentration and used in an amount 3-5% by weight of the hydrocarbons to be treated, the fresh acid added preferably being of 98% concentration. The acid treatment is effected in a mixer at 0-50 DEG C. in less than 10 mins. using at most 150 parts by vol. acid phase per 100 parts hydrocarbon phase, and is followed by separation of the phases in a settler and de-acidification of the hydrocarbon by means of a solid caustic alkali bed or, more preferably, a neutral or alkaline wash liquid such as water, milk of lime, NaOH or KOH, the pressure being sufficient to maintain the liquid phase of the hydrocarbon. The subsequent fractional distillation employs a reflux ratio of at most 5:1 and may, if required, be operated to separate odourless propane and butane, for example, individually. The products are useful as aerosol propellants.
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