Toluene in gasoline

In summary, in order to reduce the content of toluene in gasoline while keeping a high octane number, toluene must undergo hydrogenation and ring contraction followed by SRO. The RC step can proceed via bifunctional catalysts and the SRO must use a metal catalyst (e.g. Ir/Si02) that is selective towards the dicarbene mechanism to cleave C-C bonds at unsubstituted positions. 

Poole SK, Furton KG, Poole CF. 1988. Determination of benzene and toluene in gasoline by gas chromatography using a liquid organic salt column. J Chromatogr Sci 26 67-73. 

FIGURE 13.28 Typical chromatogram for ASTM D-3606 for benzene and toluene in gasoline. (Reprinted with permission from Reference 84, Wasson-ECE Instrumentation.)... 

Stannic Chloride. Stannic chloride is available commercially as anhydrous stannic chloride, SnCl (tin(IV) chloride) stannic chloride pentahydrate, SnCl 5H20 and in proprietary solutions for special appHcations. Anhydrous stannic chloride, a colorless Aiming Hquid, fumes only in moist air, with the subsequent hydrolysis producing finely divided hydrated tin oxide or basic chloride. It is soluble in water, carbon tetrachloride, benzene, toluene, kerosene, gasoline, methanol, and many other organic solvents. With water, it forms a number of hydrates, of which the most important is the pentahydrate. Although stannic chloride is an almost perfect electrical insulator, traces of water make it a weak conductor. 

Toluene, Benzene, and BTX Reeoveiy. The composition of aromatics centers on the C - and Cg-fraction, depending somewhat on the boihng range of the feedstock used. Most catalytic reformate is used directiy in gasoline. That part which is converted to benzene, toluene, and xylenes for commercial sale is separated from the unreacted paraffins and cycloparaffins or naphthenes by hquid—hquid extraction or by extractive distillation. It is impossible to separate commercial purity aromatic products from reformates by distillation only because of the presence of azeotropes, although comphcated further by the closeness in boihng points of the aromatics, t/o-paraffin, and unreacted C -, C -, and Cg-paraffins. 

Eeedstock Wt % to pyrolysis gasoline Wt % toluene in pyrolysis gasoline... 

Phillips and Xu have presented two-dimensional (2D) chromatograms of kerosines, separated with different stationary phase combinations, in many thousands of components (37). Frysinger et al. have separate benzene-toluene-ethyl benzene-xylenes (BTEX) and total aromatics in gasolines by using GC X GC... 

Samples for determination of ionic alky Head species in marine fauna were homogenized in the presence of salts and the alkyllead component was extracted with toluene and oxidized with HN03. Determination was by DPASV115. A method based on oxidation on Hg electrode has been described116 for analysis of alkylleads in gasoline. Alkylation of Hg is involved, of course, but as an oxidation the method does not suffer from the background of atmospheric oxygen. The peak potentials Ev for oxidation of tetramethyllead and tetraethyllead on various cathodes are well resolved (Table 5). 

Benzene and para-xylene are the most sought after components from reformate and pygas, followed by ortho-xylene and meta-xylene. While there is petrochemical demand for toluene and ethylbenzene, the consumption of these carmot be discussed in the same way as the other four. Toluene is used in such a large quantity in gasoline blending that its demand as a petrochemical pales in comparison. Fthylbenzene from reformate and pygas is typically dealkylated to make benzene or isomerized to make xylenes. On-purpose production of petrochemical ethylbenzene (via ethylene alkylation of benzene) is primarily for use as an intermediate in the production of another petrochemical, styrene monomer. Ethylbenzene plants are typically built close coupled with styrene plants. 

Harley et al. (2000) analyzed the headspace vapors of three grades of unleaded gasoline where ethanol was added to replace methyl /er/-butyl ether. The gasoline vapor concentrations of toluene in the headspace were 1.9 wt % for regular grade, 1.8 wt % for mid-grade, and 2.0 wt % for premium grade. 

A few comments on toluene Toluene (C6H5CH3) is extensively used in gasoline to boost the octane number it is also the raw material in the production of other chemicals such as benzene, benzyl chloride, phenol, cresols, vinyl toluene, and TNT. It also finds use in the production of paints, coatings, adhesives, etc. 

Toluene is used as a high-octane blending stock in gasoline as a solvent for paints and coatings, gums, resins, oils, rubber and adhesives and as an intermediate in the preparation of many chemicals, dyes, pharmaceuticals, detergents and explosives (Lewis, 1993). 

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