Heptane

Description

n-Heptane is a clear liquid which is highlyflammable and volatile with a mild, gasoline-like odor. Theodor threshold is 40- 547 ppm; also reported at 230 ppm.Molecular weight = 100.23; Specific gravity (H2O:l)= 0.68;Boiling point = 98.39C; FreezingMelting point= - 90.6℃;Vapor pressure = 40 mmHg at 25℃; Flash point= 一4℃;Autoignition temperature = 204℃.285℃. Explosivelimits:LEL= 1.1%; UEL= 6.7%.Hazard Identification(basedonNFPA-704 M Rating System): Health 1,Flammability 3, Reactivity 0. Practically insoluble in water;solubility = 0.0003%.

Chemical properties

n-Heptane is a flammable liquid, present in crude oil and widely used in the auto- mobile industry. For example, as a solvent, as a gasoline knock testing standard, as automotive starter fl uid, and paraffi nic naphtha. n-Heptane causes adverse health effects in occupational workers, such as CNS depression, skin irritation, and pain. Other compounds such as n-octane (CH 3 (CH 2 ) 6 CH 3 ), n-nonane (CH 3 (CH 2 ) 7 CH 3 ), and n-decane (CH 3 (CH 2 ) 8 CH 3 ) have different industrial applications. Occupational workers exposed to these compounds also show adverse health effects. In principle, manage- ment of these aliphatic compounds requires proper handling and disposal to avoid health problems and to maintain chemical safety standards for safety to workers and the living environment.

Chemical properties

n-Heptane is a clear liquid which is highly flammable and volatile with a mild, gasoline-like odor. The odor threshold is 40 547 ppm; also reported @ 230 ppm.

Physical properties

Clear, colorless, very flammable liquid with a faint, pleasant odor resembling hexane or octane. Based on a triangle bag odor method, an odor threshold concentration of 670 ppb_v was reported by Nagata and Takeuchi (1990).

The Uses of Heptane

heptane is a solvent and viscosity-decreasing agent.

The Uses of Heptane

To a solution of A (400 mg, 1.54 mmol), B (621 mg, 3.09 mmol), and PPh3 (610 mg, 2.32 mmol) in THF (5.5 mL) at RT was added DEAD (404 mg, 2.32 mmol) in THF (0.5 mL). After 90 min, silica gel was added and the mixture was concentrated and purified on a flash column (25% EtOAc/hexane) to provide the product. [545 mg, 80%]

The Uses of Heptane

Suitable for HPLC, spectrophotometry, environmental testing

The Uses of Heptane

As standard in testing knock of gasoline engines.

What are the applications of Application

Heptane is a common single chain nonpolar organic solvent

Definition

A colorless liquid alkane obtained from petroleum refining. It is used as a solvent.

Definition

heptane: A liquid straight-chainalkane obtained from petroleum,C₇H₁₆; r.d. 0.684; m.p. -90.6°C; b.p.98.4°C. In standardizing octanenumbers, heptane is given a valuezero.

Production Methods

Heptane is produced in refining processes. Highly purified heptane is produced by adsorption of commercial heptane on molecular sieves.

Synthesis Reference(s)

Tetrahedron Letters, 3, p. 43, 1962 DOI: 10.1007/BF01499754

General Description

Clear colorless liquids with a petroleum-like odor. Flash point 25°F. Less dense than water and insoluble in water. Vapors heavier than air.

Air & Water Reactions

Highly flammable. Insoluble in water.

Reactivity Profile

HEPTANE is incompatible with the following: Strong oxidizers .

Hazard

Toxic by inhalation. Flammable, dangerous fire risk.

Health Hazard

VAPOR: Not irritating to eyes, nose or throat. If inhaled, will cause coughing or difficult breathing. LIQUID: Irritating to skin and eyes. If swallowed, will cause nausea or vomiting.

Fire Hazard

FLAMMABLE. Flashback along vapor trail may occur. Vapor may explode if ignited in an enclosed area.

Chemical Reactivity

Reactivity with Water No reaction; Reactivity with Common Materials: No reactions; Stability During Transport: Stable; Neutralizing Agents for Acids and Caustics: Not pertinent; Polymerization: Not pertinent; Inhibitor of Polymerization: Not pertinent.

Potential Exposure

n-Heptane is used in graphics, textiles, adhesives, and coatings; as an industrial solvent and in the petroleum refining process; as a standard in testing knock of gasoline engines.

First aid

If this chemical gets into the eyes,Iremove; anycontact lenses at once and irrigate immediately for at least 15 min, occasionally lifting upper and lower lids. Seek med-ical ;attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately. Ifthis chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, includ-ing resuscitation mask) if breathing has stopped and CPR ifheart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, get medi-cal attention. Give large quantities of water and induce :vomiting. Do not make an unconscious person vomit.

Source

Schauer et al. (1999) reported heptane in a diesel-powered medium-duty truck exhaust at an emission rate of 470 g/km.
Identified as one of 140 volatile constituents in used soybean oils collected from a processing plant that fried various beef, chicken, and veal products (Takeoka et al., 1996).
Schauer et al. (2001) measured organic compound emission rates for volatile organic compounds, gas-phase semi-volatile organic compounds, and particle-phase organic compounds from the residential (fireplace) combustion of pine, oak, and eucalyptus. The gas-phase emission rate of heptane was 28.9 mg/kg of pine burned. Emission rates of heptane were not measured during the combustion of oak and eucalyptus.
California Phase II reformulated gasoline contained heptane at a concentration of 9,700 mg/kg.
Gas-phase tailpipe emission rates from gasoline-powered automobiles with and without catalytic converters were 1.82 and 268 mg/km, respectively (Schauer et al., 2002).

Environmental Fate

Biological. Heptane may biodegrade in two ways. The first is the formation of heptyl hydroperoxide, which decomposes to 1-heptanol followed by oxidation to heptanoic acid. The other pathway involves dehydrogenation to 1-heptene, which may react with water forming 1- heptanol (Dugan, 1972). Microorganisms can oxidize alkanes under aerobic conditions (Singer and Finnerty, 1984). The most common degradative pathway involves the oxidation of the terminal methyl group forming the corresponding alcohol (1-heptanol). The alcohol may undergo a series of dehydrogenation steps forming heptanal followed by oxidation forming heptanoic acid. The acid may then be metabolized by β-oxidation to form the mineralization products, carbon dioxide and water (Singer and Finnerty, 1984). Hou (1982) reported hexanoic acid as a degradation product by the microorganism Pseudomonas aeruginosa.
Photolytic. The following rate constants were reported for the reaction of hexane and OH radicals in the atmosphere: 7.15 x 10^-12 cm³/molecule?sec (Atkinson, 1990). Photooxidation reaction rate constants of 7.19 x 10^-12 and 1.36 x 10^-16 cm³/molecule?sec were reported for the reaction of heptane with OH and NO3, respectively (Sablji? and Güsten, 1990). Based on a photooxidation rate constant 7.15 x 10^-12 cm³/molecule?sec for heptane and OH radicals, the estimated atmospheric lifetime is 19 h in summer sunlight (Altshuller, 1991).
Chemical/Physical. Complete combustion in air yields carbon dioxide and water vapor. Heptane will not hydrolyze because it has no hydrolyzable functional group.

storage

Color Code- _Red: Flammability Hazard: Store ina flammable liquid storage area or approved cabinet awayfrom ignition sources and corrosive and reactive materials.Prior to working with heptane you should be trained on itsproper handling and storage. Before entering confined spacewhere heptane may be present, check to make sure that anexplosive concentration does not exist. Store in tightlyclosed containers in a cool, well-ventilated area. Metalcontainers involving the transfer of this chemical should be grounded and bonded. Where possible, automatically pumpliquid from drums or other storage containers to processcontainers.Drums must be equipped with self-closingvalves, pressure vacuum bungs, and flame arresters. Useonly nonsparking tools and equipment, especially whenopening and closing containers of this chemical. Sources ofignition, such as smoking and open flames, are prohibitedwhere this chemical is used, handled, or stored in a mannerthat could create a potential fire or explosion hazard.Wherever this chemical is used, handled, manufactured, orstored, use explosion-proof electrical equipment and fittings.

Shipping

UN1206 Heptanes, Hazard Class: 3; Labels: 3-Flammable liquid.

Toxicity evaluation

The acute mechanism of toxicity is suspected be similar to other solvents that rapidly induce anesthesia-like effects, i.e., a ‘nonspecific narcosis’ because of disruption (solvation) of the integrity of the cellular membranes of the central nervous system (CNS). This disruptive narcosis may also contribute to the pathology seen with chronic toxicity, although the gamma diketone metabolite of n-heptane would be responsible for any delayed peripheral neurotoxicity seen in humans following chronic exposure, similar to the mechanism seen for hexane. Although the mechanism of toxicity of n-heptane, with respect to polyneuropathy, is believed to be similar to hexane, human exposures in the workplace are often a mixture of other solvents and the animal data are not compelling.
Heptane is generally considered to be less toxic than hexane but slightly more toxic than octane. This is probably because it is less volatile than the former but more volatile than the latter (consistent with the nonspecific narcotic mechanism of toxicity of volatile organic compounds). If it is aspirated into the lungs, however, n-heptane will cause adverse effects similar to those seen with petroleum distillates.

Incompatibilities

May form explosive mixture with air. Strong oxidizers may cause fire and explosions. Attacks some plastics, rubber and coatings. May accumulate static electric charges that can ignite 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.