Login
Login

:Heptane

{{Short description|Chemical compound (C7H16)}}

{{Distinguish|heptene|heptyne}}

{{Use dmy dates|date=March 2018}}

{{Chembox

| Watchedfields = changed

| verifiedrevid = 443853887

| ImageFile = Heptane-2D-Skeletal.svg

| ImageClass = skin-invert-image

| ImageFile_Ref = {{chemboximage|correct|??}}

| ImageAlt = Skeletal formula of heptane

| ImageFile1 = HeptaneFull.png

| ImageClass1 = skin-invert-image

| ImageFile1_Ref = {{chemboximage|correct|??}}

| ImageAlt1 = Skeletal formula of heptane of all implicit carbons shown, and all explicit hydrogens added

| ImageFile2 = Heptane 3D ball.png

| ImageClass2 = bg-transparent

| ImageFile2_Ref = {{chemboximage|correct|?}}

| ImageAlt2 = Ball-and-stick model of the heptane molecule

| PIN = Heptane{{Cite web|title=n-heptane – Compound Summary|url=https://pubchem.ncbi.nlm.nih.gov/summary/summary.cgi?cid=8900&loc=ec_rcs|work=PubChem Compound|publisher=National Center for Biotechnology Information|access-date=2 January 2012|location=USA|date=16 September 2004|at=Identification and Related Records}}

| OtherNames = Septane{{cite journal|title=I. On the action of trichloride of phosphorus on the salts of the aromatic monamines|first=August Wilhelm Von|last=Hofmann|date=1 January 1867|journal=Proceedings of the Royal Society of London|volume=15|pages=54–62|doi=10.1098/rspl.1866.0018|s2cid=98496840}}

|Section1={{Chembox Identifiers

| CASNo = 142-82-5

| CASNo_Ref = {{cascite|correct|CAS}}

| PubChem = 8900

| ChemSpiderID = 8560

| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}

| UNII = 456148SDMJ

| UNII_Ref = {{fdacite|correct|FDA}}

| EINECS = 205-563-8

| UNNumber = 1206

| MeSHName = n-heptane

| ChEBI = 43098

| ChEBI_Ref = {{ebicite|correct|EBI}}

| ChEMBL = 134658

| ChEMBL_Ref = {{ebicite|correct|EBI}}

| RTECS = MI7700000

| Beilstein = 1730763

| Gmelin = 49760

| SMILES = CCCCCCC

| StdInChI = 1S/C7H16/c1-3-5-7-6-4-2/h3-7H2,1-2H3

| StdInChI_Ref = {{stdinchicite|correct|chemspider}}

| StdInChIKey = IMNFDUFMRHMDMM-UHFFFAOYSA-N

| StdInChIKey_Ref = {{stdinchicite|correct|chemspider}}

}}

|Section2 = {{Chembox Properties

| C=7 | H=16

| Appearance = Colourless liquid

| Odor = Petrolic

| Density = 0.6795 g cm−3

| MeltingPtC = −90.549{{RubberBible92nd|page=3.290}}

| BoilingPtC = 98.38

| LogP = 4.274

| VaporPressure = 5.33 kPa (at 20.0 °C)

| HenryConstant = 12 nmol Pa−1 kg−1

| RefractIndex = 1.3855

| Viscosity = 0.389 mPa·s{{cite journal|last1=Dymond|first1=J. H.|last2=Oye|first2=H. A.|title=Viscosity of Selected Liquid n-Alkanes|journal=Journal of Physical and Chemical Reference Data|volume=23|issue=1|year=1994|pages=41–53|issn=0047-2689|doi=10.1063/1.555943|bibcode=1994JPCRD..23...41D}}

| Dipole = 0.0 D

| Solubility = 0.0003% (20 °C)

| MagSus = −85.24·10−6 cm3/mol

}}

|Section3 = {{Chembox Thermochemistry

| DeltaHf = −225.2 – −223.6 kJ mol−1

| DeltaHc = −4.825 – −4.809 MJ mol−1

| Entropy = 328.57 J K−1 mol−1

| HeatCapacity = 224.64 J K−1 mol−1

}}

|Section4 = {{Chembox Hazards

| GHSPictograms = {{GHS flame}} {{GHS exclamation mark}} {{GHS health hazard}} {{GHS environment}}

| GHSSignalWord = DANGER

| HPhrases = {{H-phrases|225|304|315|336|410}}

| PPhrases = {{P-phrases|210|261|273|301+310|331}}

| NFPA-H = 1

| NFPA-F = 3

| NFPA-R = 0

| FlashPtC = −4.0

| AutoignitionPtC = 223.0

| ExploLimits = 1.05–6.7%

| PEL = TWA 500 ppm (2000 mg/m3){{PGCH|0312}}

| IDLH = 750 ppm

| REL = TWA 85 ppm (350 mg/m3) C 440 ppm (1800 mg/m3) [15-minute]

| LCLo = 16,000 ppm (human)
15,000 ppm (mouse, 30 min){{IDLH|142825|n-Heptane}}

| LC50 = 17,986 ppm (mouse, 2 hr)

}}

|Section5 = {{Chembox Related

| OtherFunction_label = alkanes

| OtherFunction = {{Unbulleted list|Hexane|Octane}}

}}

}}

Heptane or n-heptane is the straight-chain alkane with the chemical formula H3C(CH2)5CH3 or C7H16. When used as a test fuel component in anti-knock test engines, a 100% heptane fuel is the zero point of the octane rating scale (the 100 point is 100% iso-octane). Octane number equates to the anti-knock qualities of a comparison mixture of heptane and iso-octane which is expressed as the percentage of iso-octane in heptane, and is listed on pumps for gasoline (petrol) dispensed globally.

History

Normal heptane was discovered in 1862 by Carl Schorlemmer, who, while analyzing pyrolysis products of the cannel coal mined in Wigan, identified, separated by fractional distillation and studied a series of liquid hydrocarbons inert to nitric and sulfuric acids. One of them, which he called hydride of heptyl (oenanthyl), had an empirical formula of C7H16, density of 0.709 at 18 °C and boiled between 98 and 99 °C.{{Cite journal |last=Schorlemmer |first=C. |date=1862 |title=On the hydrides of the alcohol-radicles existing in the products of the destructive distillation of cannel coal |url=https://books.google.com/books?id=51fYFmBb7_kC&pg=PA419 |journal=Journal of the Chemical Society |language=en |volume=15 |pages=419–427 |doi=10.1039/JS8621500419 |issn=0368-1769}} In the next year he identified the same compound in the Pennsylvanian oil.{{Cite book |last= |first= |url=https://books.google.com/books?id=fTw9AQAAMAAJ&pg=RA1-PA81 |title=Proceedings of the Literary and Philosophical Society of Manchester |date=1864 |language=en}} By 1872 he switched his nomenclature to the modern one.{{Cite journal |last=Schorlemmer |first=Carl |date=1872 |title=On the normal paraffins |url=https://books.google.com/books?id=Sow5AQAAMAAJ&pg=PA120 |journal=Philosophical Transactions of the Royal Society of London |volume=162 |pages=111–123 |doi=10.1098/rstl.1872.0007|url-access=subscription }}

During the American Civil War and shortly thereafter Californians discovered that some pines gave turpentine with unusual properties. It took until 1879 to identify heptane as the cause of that (see below for details), and only by the end of the century was this fact accepted by European chemists.{{Cite book |last=Hill |first=Cary Le Roy |url=https://books.google.com/books?id=hAsRvdX33p8C&pg=PP13 |title=Experiments in the Production of Heptane by the Tapping of Jeffrey Pine in California |date=1932 |publisher=California Forest Experiment Station |language=en}}

Uses

Heptane and its many isomers are widely used in laboratories as a non-polar solvent.{{cite arXiv |eprint=2410.09901 |last1=Fang |first1=Shen |last2=Zhang |first2=Siyi |last3=Li |first3=Zeyu |last4=Fu |first4=Qingfei |last5=Zhou |first5=Chong-Wen |last6=Hana |first6=Wang |last7=Yang |first7=Lijun |title=A data-driven sparse learning approach to reduce chemical reaction mechanisms |date=2024 |class=physics.chem-ph }} It is often preferred to hexane due to heptane being comparatively less toxic and less volatile.{{Cite web |title=Differences Between Heptane and Hexane - Solvent Extractors |url=https://ecolink.com/info/difference-between-hexane-and-heptane/?srsltid=AfmBOop2HAJ_5JY4ZT7kT4qxej1mM8gfJFdsUHg-2Yg0ff-WxKcSyT5n |access-date=2025-03-30 |website=ecolink.com}} As a liquid, it is ideal for transport and storage. In the grease spot test, heptane is used to dissolve an oil spot to show the previous presence of organic compounds on a stained paper. This is done by shaking the stained paper in a heptane solution for about half a minute.{{Citation needed|date=July 2009}}

Aqueous bromine may be distinguished from aqueous iodine by its appearance after extraction into heptane. In water, both bromine and iodine appear brown. However, iodine turns purple when dissolved in heptane, whereas the bromine solution remains brown.

Heptane is commercially available as both pure and mixed isomers for use in paints and coatings, as the rubber cement solvent "Bestine",{{Cite web |date=27 June 2022 |title=BESTINE SOLVENT & THINNER OSHA SDS |url=https://www.speedballart.com/wp-content/uploads/2022/08/Bestine-OSHA-SDS-EN.pdf |url-status=live |archive-url=https://web.archive.org/web/20230426012051/https://www.speedballart.com/wp-content/uploads/2022/08/Bestine-OSHA-SDS-EN.pdf |archive-date=26 April 2023 |access-date=24 December 2024 |publisher=Speedball Art Products Co.}} the outdoor stove fuel "Powerfuel" by Primus, as pure n-heptane for research and development and pharmaceutical manufacturing and as a minor component of gasoline (petrol). On average, gasoline is about 1% heptane.{{cite journal |last1=Conner |first1=Teri L. |last2=Lonneman |first2=William A. |last3=Seila |first3=Robert L. |title=Transportation-Related Volatile Hydrocarbon Source Profiles Measured in Atlanta |journal=Journal of the Air & Waste Management Association |date=1 May 1995 |volume=45 |issue=5 |pages=383–394 |doi=10.1080/10473289.1995.10467370|doi-access=free |bibcode=1995JAWMA..45..383C }}{{cite journal |last1=Schauer |first1=James J. |last2=Kleeman |first2=Michael J. |last3=Cass |first3=Glen R. |last4=Simoneit |first4=Bernd R. T. |title=Measurement of Emissions from Air Pollution Sources. 5. C 1 −C 32 Organic Compounds from Gasoline-Powered Motor Vehicles |journal=Environmental Science & Technology |date=1 March 2002 |volume=36 |issue=6 |pages=1169–1180 |doi=10.1021/es0108077|pmid=11944666 |bibcode=2002EnST...36.1169S }}

Heptane is also used as an adhesive remover by stamp collectors. Since 1974, the United States Postal Service has issued self-adhesive stamps that some collectors find difficult to separate from envelopes via the traditional method of soaking in water. Heptane-based products like Bestine, as well as limonene-based products, have become popular solvents for removing stamps more easily.{{cite web |last1=Butler |first1=Peter |title=It's Like Magic: Removing Self-Adhesive Stamps from Paper |url=https://classic.stamps.org/userfiles/file/HowTos/RemovingSelfAdhesives-Part1.pdf |publisher=American Philatelic Society |access-date=15 June 2020}}

=Octane rating scale=

n-Heptane is defined as the zero point of the octane rating scale. It is a lighter component in gasoline and burns more explosively, causing engine pre-ignition (knocking) in its pure form, as opposed to octane isomers, which burn more slowly and give less knocking. It was originally chosen as the zero point of the scale because of the availability of very high purity n-heptane, unmixed with other isomers of heptane or other alkanes, distilled from the resin of Jeffrey pine and from the fruit of Pittosporum resiniferum. Other sources of heptane and octane, produced from crude oil, contain a mixture of different isomers with greatly differing ratings, and do not give as precise a zero point.

Isomers and enantiomers

{{Main|C7H16}}

Heptane has nine isomers, or eleven if enantiomers are counted:

  • Heptane (n-heptane), H3C–CH2–CH2–CH2–CH2–CH2–CH3,
  • 2-Methylhexane (isoheptane), H3C–CH(CH3)–CH2–CH2–CH2–CH3,
  • 3-Methylhexane, H3C–CH2–C*H(CH3)–CH2–CH2–CH3 (chiral),
  • 2,2-Dimethylpentane (neoheptane), H3C–C(CH3)2–CH2–CH2–CH3,
  • 2,3-Dimethylpentane, H3C–CH(CH3)–C*H(CH3)–CH2–CH3 (chiral),
  • 2,4-Dimethylpentane, H3C–CH(CH3)–CH2–CH(CH3)–CH3,
  • 3,3-Dimethylpentane, H3C–CH2–C(CH3)2–CH2–CH3,
  • 3-Ethylpentane, H3C–CH2–CH(CH2CH3)–CH2–CH3,
  • 2,2,3-Trimethylbutane, H3C–C(CH3)2–CH(CH3)–CH3, also known as pentamethylethane and triptane.[http://members.optushome.com.au/scottsoftb/skeletons3.htm Isomers] {{Webarchive|url=https://web.archive.org/web/20110927014042/http://members.optushome.com.au/scottsoftb/skeletons3.htm |date=27 September 2011 }}. Members.optushome.com.au. Retrieved on 2012-03-04.

Preparation

The linear n-heptane can be obtained from Jeffrey pine oil.{{cite journal | doi = 10.1021/ja01380a027| title = The preparation and properties of the isomeric heptanes. Part I. Preparation | date = 1929| last1 = Edgar| first1 = Graham| last2 = Calingaert| first2 = George| last3 = Marker| first3 = R. E.| journal = Journal of the American Chemical Society| volume = 51| issue = 5| pages = 1483–1491}} The six branched isomers without a quaternary carbon can be prepared by creating a suitable secondary or tertiary alcohol by the Grignard reaction, converting it to an alkene by dehydrogenation, and hydrogenating the latter. The 2,2-dimethylpentane isomer can be prepared by reacting tert-butyl chloride with n-propyl magnesium bromide. The 3,3-dimethylpentane isomer can be prepared from tert-amyl chloride and ethyl magnesium bromide.

Health risks

Acute exposure to heptane vapors can cause dizziness, stupor, incoordination, loss of appetite, nausea, dermatitis, chemical pneumonitis, unconsciousness, or possible peripheral neuropathy.{{cite journal|last1=Patty|first1= FA|last2=Yant|first2= WP|year=1929|title=Odor intensity and symptoms produced by commercial propane, butane, pentane, hexane, and heptane vapor.|journal=Report of Investigations|publisher=US Department of Commerce, U.S. Bureau of Mines|volume=2979|issue=December|pages=1–10|url=https://babel.hathitrust.org/cgi/pt?id=umn.31951000866454o;view=1up;seq=652}}

In a CDC study, it was found that prolonged exposure to heptane may also cause a state of intoxication and uncontrolled hilarity in some participants and a stupor lasting for 30 minutes after exposure for others.{{Cite web|date=2018-11-02|title=CDC - Immediately Dangerous to Life or Health Concentrations (IDLH): n-Heptane - NIOSH Publications and Products|url=https://www.cdc.gov/niosh/idlh/142825.html|access-date=2021-12-06|website=www.cdc.gov|language=en-us}} Prolonged exposure can also lead to skin dryness or cracking, since the substance defats skin.{{Cite web |title=ICSC 0657 - n-HEPTANE |url=https://chemicalsafety.ilo.org/dyn/icsc/showcard.display?p_lang=en&p_card_id=0657&p_version=2 |access-date=2024-09-11 |website=chemicalsafety.ilo.org}}

According to information from the New Jersey Department of Health and Senior Services, n-heptane can penetrate the skin, and further health effects may occur immediately or shortly after exposure to it. Exposure to n-heptane may lead to short-term health effects like irritation of the eyes, nose, or throat, headache, dizziness, or loss of consciousness; and chronic health effects, like reduced memory and concentration, sleep disturbance, and reduced coordination due to its effects on the nervous system.{{Cite web |title=n- HEPTANE |url=https://nj.gov/health/eoh/rtkweb/documents/fs/1339.pdf}}

Upon chronic exposure, it can pose a reproductive hazard or cancer risks.{{Cite web |date=2004 |title=Hazardous Substance Fact Sheet |url=https://nj.gov/health/eoh/rtkweb/documents/fs/1339.pdf |access-date=11 September 2024 |page=2}}

class="wikitable"

|+

!Route

!Side Effects

!First Aid Procedure

Ingestion

|Nausea, diarrhea, headache, stomach pain, intoxication, heart failure

|Seek medical attention

Eye Contamination

|Irritation

|Immediate irrigation

Skin Contamination

|Irritaion, dermatitis; can be absorbed and produce similar effects to inhalation

|Immediate wash with soap

Inhalation

|Irritation, coughing, difficulty breathing, headache, drowsiness, dizziness, unconsciousness, coma, death

|Respiratory support

CISCO. (2 June 2015). Safety data sheet: Heptane. Retrieved January 16, 2025, from http://www.ciscochem.com/assets/heptane-sds.pdf{{Cite web |title=N-HEPTANE {{!}} CAMEO Chemicals {{!}} NOAA |url=https://cameochemicals.noaa.gov/chemical/831 |access-date=2025-01-17 |website=cameochemicals.noaa.gov}}{{Cite web |title=CDC - NIOSH Pocket Guide to Chemical Hazards - n-Heptane |url=https://www.cdc.gov/niosh/npg/npgd0312.html |access-date=2025-01-17 |website=www.cdc.gov}}

References

{{Reflist|30em}}

External links

  • [http://www.ilo.org/legacy/english/protection/safework/cis/products/icsc/dtasht/_icsc06/icsc0657.htm International Chemical Safety Card 0657] (n-heptane)
  • [http://www.ilo.org/legacy/english/protection/safework/cis/products/icsc/dtasht/_icsc06/icsc0658.htm International Chemical Safety Card 0658] (2-methylhexane)
  • [https://www.cdc.gov/niosh/npg/npgd0312.html NIOSH Pocket Guide to Chemical Hazards]
  • [https://web.archive.org/web/20070311125739/http://physchem.ox.ac.uk/MSDS/HE/heptane.html Material Safety Data Sheet for Heptane]
  • [https://web.archive.org/web/20150923173914/http://www.ars-grin.gov/cgi-bin/duke/chemical.pl?HEPTANE Phytochemical database entry]

{{Alkanes}}

{{Hydrides by group}}

{{Authority control}}

Category:Alkanes

Category:Hydrocarbon solvents