(1) preparing a raw material, said raw material comprising light naphtha;
(2) carrying out a catalytic hydrogenation reaction on the light naphtha until it is complete, to obtain an intermediate product A, the content of benzene in the intermediate product A being 0.01%, and the content of sulfur being 0.4 ppm; the process parameters of the catalytic hydrogenation reaction being: a temperature of 140 C., the volume ratio of hydrogen to oil being 120:1, the reaction pressure being 0.2MPa
The catalyst used was loaded nickel skeleton.
(3) Intermediate product A was mixed with water and added to a first azeotropic distillation column for azeotropic distillation, and an azeotrope of water and 2,3-dimethylbutane was obtained from the top of the first azeotropic distillation column, and intermediate product B was obtained from the bottom of the column.
(4) Intermediate product B was mixed with water and added to a second azeotropic distillation column for azeotropic distillation, and an azeotrope of water and 2 -methylpentane azeotrope, separating water and 2-methylpentane after condensation; the bottom of the tower is discharged into the third azeotropic distillation column for azeotropic distillation, obtaining the azeotrope of water and 3-methylpentane from the top of the tower, separating water after condensation to obtain 3-methylpentane, wherein the 3-methylpentane contains n-hexane with a volume fraction of less than 8%; and obtaining n-hexane from the bottom of the tower. The above 3-methylpentane was adsorbed using 5A molecular sieve at atmospheric pressure and 110 C. The adsorption bed air velocity was 0.33 h-1, the regeneration pressure was -90 kPag, and the adsorption capacity of the adsorbent was 10 kg/m3, and the purity of 3-methylpentane was obtained to 99.9% after adsorption and separation, and the 5A molecular sieve was regenerated using the high-temperature water vapor displacement method to obtain desorption products, and the desorption products were incorporated into n-hexane. The product was incorporated into n-hexane.
Schauer et al. (1999) reported 3-methylpentane in a diesel-powered medium-duty truck
exhaust at an emission rate of 670 μg/km.
California Phase II reformulated gasoline contained 3-methylpentane at a concentration of 22.7
g/kg. Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without
catalytic converters were 3.76 and 512 mg/km, respectively (Schauer et al., 2002).
Photolytic. The following rate constants were reported for the reaction of 3-methylpentane and
OH radicals in the atmosphere: 4.30 x 10-9 cm3/moleculesec at 300 K (Darnall et al., 1976); 6.8 x
10-12 cm3/moleculesec at 305 K (Darnall et al., 1978); 5.7 x 10-12 cm3/moleculesec (Altshuller,
1991).
Chemical/Physical. Complete combustion in air produces carbon dioxide and water vapor. 3-
Methylpentane will not hydrolyze because it does not contain a hydrolyzable functional group.
Purify it by azeotropic distillation with MeOH, as for 2-methylpentane. Purify it for ultraviolet spectroscopy by passing it through columns of silica gel or alumina activated by heating for 8hours at 210o under a stream of nitrogen. Alternatively treat it with conc (or fuming) H2SO4, then wash it with water, aqueous 5% NaOH, water again, then dry (CaCl2, then sodium), and distil it through a long, glass helices-packed, column. [Beilstein 1 IV 363.]
