Concentrations gasoline

The separator effluent usually contains a residual dissolved gasoline concentration of 15mg/L. 

The definition of low-level contamination depends on the contaminant nature and the analytical method to be used. The concentrations of aromatic and halogenated hydrocarbons that are below 200 pg/kg are considered to be low because they fall within the calibration range of the laboratory instruments used for their analysis. A gasoline concentration in soil of 5000 pg/kg, high as it may seem, would also be within the instrument calibration range of most analytical laboratories. 

Soil samples with aromatic and halogenated hydrocarbon concentrations above 200 pg/kg or with gasoline concentrations above 5000 pg/kg are defined as samples with high VOC concentration levels. Because these concentrations exceed the calibration ranges of most analytical instruments, sample extracts must be diluted for proper quantitative analysis. EPA Method 5035 describes two sampling techniques for soil with high VOC concentrations ... 

There are limited data on the distribution pattern of gasoline in humans and animals. The distribution of gasoline (gasoline concentration measured as the ratio of the concentrations of [2-methylpentane/2,2-dimethylbutane] in sample/[2-methylpentane/2,2- dimethylbutane] in standard) was determined in a male who died following accidental ingestion of gasoline (Carnevale et al. 

The liver, gastric wall, and lungs had the highest gasoline concentrations at 663, 324, and 457 ppm, respectively. The brain, bile, and kidney contained 44.2, 59, and 51.5 ppm, respectively, while the concentrations in the blood from the brain, lungs, and heart were 29.4, 132, and 51.5 ppm, respectively. Autopsies of humans who were apparently exposed to gasoline indicated elevated blood levels of hydrocarbons such as benzene, toluene, pentane, and hexane (Brugnone et al. 

What is the fraction of gasoline recovered by the vapor recovery system that reduces the gasoline concentration in the vapor from saturation at 75°F to 35mg/L ... 

Although gas chromatography can give the concentration of each component in a petroleum gas or gasoline sample, the same cannot be said for heavier cuts and one has to be satisfied with analyses by chemical family, by carbon atom distribution, or by representing the sample as a whole by an average molecule. 

To the refiner, the question of octane numbers in future gasolines is of primary importance because it determines the course of operations, the development or on the contrary the stagnation of such and such a process. Table 5.12 thus gives an example of the typical composition by origin and concentration of different base constituents of three grades of the most common motor fuels distributed today in Europe conventional premium gasoline at 0.15 g Pb/1, Eurosuper and Superplus. 

A European Directive, 85/210/EEC, limits benzene content to 5% by volume in all gasolines regular, premium, with or without lead. This level is easily achieved, since the average value in 1993 was less than 3%. in France, for example, average benzene concentrations of 1.7% and 2.6% were reported for leaded and unleaded premium fuels, respectively, in 1993. 

One can react methanol with the tertiary olefins having five c irbon atoms (isoamylenes). This process increases the octane number of FCC olefinic C5 fractions, in order to reduce the concentration of olefins and to increase gasoline production. 

Bert, J.A., J.A. Gething, T.J. Hansel, H.K. Newhall, R.J. Peyla and D.A. Voss (1983), A gasoline additive concentrate removes combustion chamber deposits and reduces vehicle octane requirement . SAE paper No. 83-1709, Fuels and Lubricants meeting, San Francisco, CA. 

With aldehydes, primary alcohols readily form acetals, RCH(OR )2. Acetone also forms acetals (often called ketals), (CH2)2C(OR)2, in an exothermic reaction, but the equiUbrium concentration is small at ambient temperature. However, the methyl acetal of acetone, 2,2-dimethoxypropane [77-76-9] was once made commercially by reaction with methanol at low temperature for use as a gasoline additive (5). Isopropenyl methyl ether [116-11-OJ, useful as a hydroxyl blocking agent in urethane and epoxy polymer chemistry (6), is obtained in good yield by thermal pyrolysis of 2,2-dimethoxypropane. With other primary, secondary, and tertiary alcohols, the equiUbrium is progressively less favorable to the formation of ketals, in that order. However, acetals of acetone with other primary and secondary alcohols, and of other ketones, can be made from 2,2-dimethoxypropane by transacetalation procedures (7,8). Because they hydroly2e extensively, ketals of primary and especially secondary alcohols are effective water scavengers. 

Dyes. Dyes are added to gasoline to impart color for a number of reasons. Originally, these compounds were used to identify leaded gasoline so that it would not be used for other inappropriate purposes, such as solvents. Dyes are used to identify different gasoline grades so that pipeline companies can separate tenders, and so that service stations can easily check that the correct grade was placed in the underground tanks (aq). Dyes are usually based on a2o chemistry and are added in concentrations below 10 ppm (see Azo dyes). 

LPG recovered from natural gas is essentially free of unsaturated hydrocarbons, such as propylene and butylenes (qv). Varying quantities of these olefins may be found in refinery production, and the concentrations are a function of the refinery s process design and operation. Much of the propylene and butylene are removed in the refinery to provide raw materials for plastic and mbber production and to produce high octane gasoline components. 

---