gasoline

Description

Known as petrol to the British and benzin to the Germans, is a mixture of C4 to Cl2 hydrocarbons. Natural gasoline obtained by fractional distillation of petroleum contains mostly saturated hydrocarbons. The ordinary commercial grades of motor gasoline contain paraffins, olefins, naphthenes, and aromatics, all in substantial concentrations. Motor gasolines are made chiefly by cracking processes in which heavier petroleum factions are converted into more volatile fractions by thermal or catalytic decomposition. Where petroleum is scarce, as in Germany, gasoline also has been made commercially by catalytic high-pressure hydrocarbons from carbon monoxide and hydrogen. Some gasolines sold in the USA contain a minor proportion of tetraethyllead, which is added in concentrations not exceeding 3 mil per gallon of motor gasoline to prevent "knock" in engines in which the gasoline is used as fuel. Commercial grades of tetraethyllead or Ethyl fluid typically contain about 63% tetraethyllead and about 35% ethylene dichloride or dibromide which aids in evacuating the products of the lead from engines. In addition, the fluid contains a red or a blue dye. All leaded gasolines are dyed for recognition and should be used only as motor fuel. Other materials occasionally blended in gasoline, particularly in Europe, to decrease knock are benzene and ethanol.
Gasoline is a highly flammable, mobile liquid with characteristic odor. Evaporates quickly and is insoluble in water, freely soluble in alcohol, ether, chloroform, and benzene; and dissolves fats, oils, and natural resins. Used as fuel in internal combustion engines ofthe spark-ignitedreciprocating type.

Description

Gasoline is a product of petroleum refining that varies in composition and often includes additives such as antiknock agents, antioxidants, lubricants, and detergents. Tetraethyl lead was one of these additives, and use of leaded gasoline as fuel was responsible for much of the human body burden of this metal for a number of years. However, the phase out of lead from gasoline during the past three decades (in the United States and Europe) has led to an over 90% reduction in human blood lead levels. More recently, other additives such as methylcyclopentadienyl manganese tricarbonyl and methyl t-butyl ether have been foci of concern because of possible adverse environmental impacts of these compounds.

Chemical Properties

Gasoline is a highly flammable, mobile liquid with a characteristic odor. A complex mixture of volatile hydrocarbons (paraffins, cycloparaffins, and aromatics). Physical property values may vary depending on grade. The Odor Threshold is 0.25 ppm.

Uses

Fuel for spark-ignited internal combustion engines

Uses

Highly flammable, dangerous fire, and explosion risk. Eye and upper respiratory tract irritant, and central nervous system impairment. Possible carcinogen.

Uses

The distillation ranges of gasoline are specified for the particular application, mainly the reciprocating, spark ignition, and internal combustion engines. To serve specific purposes, various functional additives are blended into gasolines. These consist of antiknock fluids, antioxidants, metal deactivators, corrosion inhibitors, anti-icing agents, preignition preventors, upper cylinder lubricants, dyes, and decolorizers (161). Probably the most critical property is the octane number, supplied with high octane hydrocarbons and lead compounds. The major components are primarily paraffins, olefins, naphthenes, and aromatics, and more recently 10–40% ethyl alcohol. The distillation from initial to final boiling point ranges from about 32 to 225℃(90 to 437°F), and the explosive limits are 1.31–6.0%.

Definition

A mixture of volatile hydrocarbons suitable for use in a spark-ignited internal-combustion engine and having an octane number of at least 60. The major components are branched-chain paraffins, cycloparaffins, and aromatics. There are several methods of pr

Reactivity Profile

GASOLINE may be incompatible with strong oxidizing agents such as nitric acid, peroxides, and perchlorates. Charring may occur followed by ignition of unreacted hydrocarbon and other nearby combustibles. In other settings, mostly unreactive. Not affected by aqueous solutions of acids, alkalis, most oxidizing agents, and most reducing agents. When heated sufficiently or when ignited in the presence of air, oxygen or strong oxidizing agents, burns exothermically to produce carbon dioxide and water.

Health Hazard

INHALATION causes irritation of upper respiratory tract; central nervous system stimulation followed by depression of varying degrees ranging from dizziness, headache, and incoordination to anesthesia, coma, and respiratory arrest; irregular heartbeat is dangerous complication. ASPIRATION causes severe lung irritation with coughing, gagging, dyspnea, substernal distress, and rapidly developing pulmonary edema; later, signs of bronchopneumonia and pneumonitis; acute onset of central nervous system followed by depression. INGESTION causes irritation of mucous membranes of throat, esophagus, and stomach; stimulation followed by depression of central nervous system; irregular heartbeat.

Flammability and Explosibility

Extremely flammable

Agricultural Uses

Gasoline, also known as petrol, is a mixture of volatile hydrocarbons having 4 to 12 carbon atoms per molecule. It has an octane number of at least 60. It is used as fuel for internal combustion engines and as a solvent. The major components of gasoline are branched-chain paraffins, cycloparaffins and aromatics.
There are several methods used for the production of gasoline. Among these, distillation or fractionation yields a straight run product of relatively low octane number, which is used primarily for blending, thermal and catalytic cracking, reforming, polymerization, isomerization and dehydrocyclodimerization. The various means of converting hydrocarbon gases into motor fuels by modification of chemical structure usually makes use of catalysts. The present source of gasoline is petroleum; gasoline may also be produced from shale oil and tar sands as well as by gasification of coal.
While gasoline can be synthesized from carbon monoxide and hydrogen, almost all gasoline is made by refining, cracking and alkylation. The fractions are blended to produce the required fuels. Motor gasoline boils between 30°C and 200°C. If the fuel is too volatile, the vapor bubbles are formed which hinder the flow of fuel (vapor lock).
Different kinds of gasoline are:
(a) Cracked gasoline: Gasolines are produced by catalytic decomposition of high-boiling components of petroleum. Such gasolines have higher octane ratings than that produced by fractional distillation. The difference is due to a higher content of unsaturated, aromatic and branched-chain hydrocarbons. The actual properties vary widely depending on the source, temperature, pressure and the catalyst used in cracking.
(b) High-octane gasoline: It is a gasoline with an octane value of 90to 100.
(c) Lead-free gasoline: It is a gasoline containing no more than 0.05 g of lead per 4.5 1 designed for use in engines equipped with a catalytic converter.
(d) Natural gasoline: It is the gasoline based on butane, pentane and hexane hydrocarbons. It is used in blending to produce finished gasoline with adjusted volatility but having a low octane number.
(e) Polymer gasoline: A gasoline produced by polymerization of low molecular weight hydrocarbons such as ethylene, propene and butene is called polymer gasoline. It is used in small amounts for blending with other gasolines to improve their octane number.
(f) Pyrolysis gasoline: Gasolinep roduced by thermal cracking as a by-product of ethylene manufacture is pyrolysis gasoline. It is used as a source of benzene.
(8) Reformed gasoline: It is a high octane gasoline obtained from low octane gasoline by heating the vapors to high temperatures or passing the vapors over a catalyst.
(h) Straight-run gasoline: Gasoline produced by distillation, without the use of cracking or other chemical conversion processes, is called straight-run gasoline.
(i) White gasoline: It is an unleaded gasoline especially designed for use in motor boats. It is uncracked and strongly inhibited against oxidation to avoid gum formation, and is usually not colored to distinguish it from other grades. It also serves as a fuel for camp lanterns and portable stoves.
Aviation fuel contains a less of low and high boiling components. The octane number or maximum power is carefully controlled by the structure of gasoline components. The gasoline may further be improved by an antiknocking additive. Other additives include lead scavengers (ethylene bromide), antioxidants, metal deactivators, anti-icing agents and detergents. The host of properties exhibited by gasolines results from the use of additives. These gasolines are used as a source of hydrogen in ammonia manufacture and as a source of energy for tractors and jeeps.

Industrial uses

Gasoline is a colorless liquid hydrocarbonobtained in the fractional distillation of petroleum.It is used chiefly as motor fuel, but alsoas a solvent. Ordinary gasoline consists of thehydrocarbons between C₆H₁₄ and C₁₀H₂₂, whichdistill off between the temperatures 69 and174°C, usually having the light limit at heptane,C₇H₁₆,or octane, C₈H₁₈.The octane number isthe standard of measure of detonation in theengine. Motor fuel, or the general name gasoline,before the wide use of high-octane gasolinesobtained by catalytic cracking meant anyhydrocarbon mixture that could be used as afuel in an internal-combustion engine by sparkignition without being sucked in as a liquid andwithout being so volatile as to cause imperfectcombustion and carbon deposition. Theseincluded also mixtures of gasoline with alcoholor benzol.

Safety Profile

Confirmed carcinogen. Mildly toxic by inhalation. Human systemic effects by inhalation: cough, conjunctiva irritation, hallucinations or distorted per ceptions. Repeated or prolonged dermal ex posure causes dermatitis. Can cause blister ing of skin. Inhalation or ingestion can cause central nervous system depression. Pulmon ary aspiration can cause severe pneumonitis. Some addiction has been reported from inhalation of fumes. Even brief inhalations of high concentrations can cause a fatal pulmonary edema. The vapors are consider ed to be moderately poisonous. If its con-centration in air is sufficiently high to reduce the oxygen content below that needed to maintain life, it acts as a simple asphyxiant. A human eye irritant. Gasohe is a common air contaminant. A very dangerous fire and explosion hazard when exposed to heat or flame; can react vigorously with oxidizing materials. To fight fKe, use foam, CO2, dry chemical.

Potential Exposure

Gasoline is used as a fuel, diluent, and solvent throughout industry.

Environmental Fate

Since gasoline is a mixture, no simple summary can address the fates of all of the components. However, many of the toxicologically significant components are volatile and so are lost to the atmosphere after being released to surface soil or surface water. These compounds are then subject to photochemical oxidation.
In addition, these components can leach through the soil and contaminate groundwater where they may remain for long periods of time. Under aerobic conditions, biodegradation of gasoline components can occur in soil and surface water.

Shipping

UN1203 Gasoline includes gasoline mixed with ethyl alcohol, with not >10% alcohol, Hazard Class: 3; Labels: 3-Flammable liquid.

Toxicity evaluation

Little information is available on most of the mechanisms of toxicity of gasoline. It has been suggested, however, that renal effects in rats are mediated by alpha-2-urinary globulin and thus of little relevance to humans who do not produce this protein.

Incompatibilities

May form explosive mixture with air. Strong oxidizers may cause fire and explosions. Incompatible with nitric acid. May accumulate static elec trical charges, and may cause ignition of its vapors.

Waste Disposal

Dissolve or mix the material with a combustible solvent and burn in a chemical incinera tor equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed. Alternatively, gasoline vapors may be recovered from fuel transfer operations by various techniques.