هيبتان

يجب ألا يـُخلـَط بينها وبين heptene or heptyne.

هيبتان

الأسماء
اسم أيوپاك المفضل Heptane
أسماء أخرى Septane
المُعرِّفات
رقم CAS
3D model (JSmol)	Interactive image
مرجع بايلستاين	1730763
ChEBI	CHEBI:43098 Y
ChEMBL	ChEMBL134658 Y
ChemSpider	8560 Y
رقم EC	205-563-8
مرجع Gmelin	49760
عناوين مواضيع طبية MeSH	{{{value}}}
PubChem CID	8900
رقم RTECS	MI7700000
UNII	456148SDMJ Y
UN number	1206
InChI InChI=1S/C7H16/c1-3-5-7-6-4-2/h3-7H2,1-2H3 Y Key: IMNFDUFMRHMDMM-UHFFFAOYSA-N Y
SMILES CCCCCCC
الخصائص
الصيغة الجزيئية	C7H16
كتلة مولية	100.2 g mol-1
المظهر	Colourless liquid
الرائحة	Petrolic
الكثافة	0.6795 g.cm-3
نقطة الانصهار
نقطة الغليان
قابلية الذوبان في الماء	insoluble
log P	4.66
ضغط البخار	5.33 kPa (0.773 psi) (20 °C (68 °F; 293 K))
kH	12 nmol/(Pa·kg)
القابلية المغناطيسية	−85.24×10−6 cm3/mol
معامل الانكسار (nD)	1.3855
اللزوجة	0.389 mPa·s
الكيمياء الحرارية
الإنتالپية المعيارية للتشكل ΔfHo298	−225.2 to −223.6 kJ⋅mol−1
الانتالبية المعيارية للاحتراق ΔcHo298	−4.825 to −4.809 MJ⋅mol−1
Standard molar entropy So298	328.57 J⋅mol−1·K-1
سعة الحرارة النوعية، C	224.64 J⋅mol−1·K-1
المخاطر
ن.م.ع. مخطط تصويري
ن.م.ع. كلمة الاشارة	Danger
ن.م.ع. عبارات المخاطر	H225, H304, H315, H336, H410
ن.م.ع. العبارات الاحتياطية	P210, P233, P240, P241, P242, P243, P261, P264, P271, P273, P280, P301+P310, P303+P361+P353, P304+P340+P312, P331, P332+P313, P362, P370+P378, P391, P403+P233, P403+P235, P405, P501
NFPA 704 (معيـَّن النار)	3 3 0
نقطة الوميض	−4 °C (25 °F; 269 K)
درجة حرارة الاشتعال الذاتي	215 °C (419 °F; 488 K)
حدود الانفجار	1.05%–6.7%
قيمة حد العتبة	200 ppm (TWA), 400 ppm (STEL)
الجرعة أو التركيز القاتل (LD, LC):
LD50 (الجرعة الوسطى)	>2000 mg/kg (rat, oral) 3000 mg/kg (rabbit, dermal)
LC50 (التركيز الأوسط)	17,986 ppm (mouse, 2 hr)
LCLo (المنشورة الأقل)	16,000 ppm (human) 15,000 ppm (mouse, 30 min)
حدود التعرض الصحية بالولايات المتحدة (NIOSH):
PEL (المسموح)	TWA 500 ppm (2000 mg/m3)
REL (الموصى به)	TWA 85 ppm (350 mg/m3) C 440 ppm (1800 mg/m3, 15 minute)
IDLH (خطر عاجل)	750 ppm
مركبات ذا علاقة
alkanes ذات العلاقة	Hexane Octane
ما لم يُذكر غير ذلك، البيانات المعطاة للمواد في حالاتهم العيارية (عند 25 °س [77 °ف]، 100 kPa).
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مراجع الجدول

الهـپتان Heptane (يعرف أيضا اثنائي ميثيل ميثان, جيتيوسولف-سي, gettysolve-C, هيدريد هيبتيل) هو من الهيدروكربونات. كما أن الهيبتان ألكان له الصيغة الكيميائية CH₃(CH₂)₅CH₃. الهيبتان له 9 متزامرات (isomer).

المتزامر إن-هيبتان (السلسلة المستقيمة للهيبتان) تم إختياره كنقطة الصفر في مقياس تقيييم الأوكتان. وهو من المواد الغير مفضل وجودها في النفط, حيث انه يحترق بإنفجار, مما يسبب طرْقات في المحرك، وعلى العكس، فإن متزامر الأوكتان الذى له سلسلة متفرعة، يحترق ببطء ويعطي أداءً جيداً للمحركات. وقد تم إختيار إن-هيبتان كنقطة الصفر نظرا لأنه لإمكانية تواجده في صورة عالية النقاوة, الغير مختلطة بالمتزامرات الأخرى للهيبتان والألكانات الأخرى, ويتم الحصول عليه من راتينج جيفري بين. ويمكن الحصول أيضا على كل من الهيبتان والأوكتان من الزيت الخام, ولكنه يحتوى على خليط من المتزامرات الأخرى بنسب متغيرة، ولذا لا يكون لإستخدامه كنقطة صفر في مقياس الأوكتان.

 التاريخ

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 C
7H
16, density of 0.709 g/mL at 18 °C (64 °F) and boiled between 98–99 °C (208–210 °F). In the next year he identified the same compound in the Pennsylvanian oil. By 1872 he switched his nomenclature to the modern one.

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.

 الاستخدامات

Heptane and its many isomers are widely used in laboratories as non-polar solvents. As a liquid, it is ideal for transport and storage.قالب:Compared to?

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" and as a pure n-heptane for research and development and pharmaceutical manufacturing.

It is a minor component of most gasoline. On average, gasoline is about 1% heptane.

Heptane is also used as an adhesive remover by stamp collectors. Since 1974, the United States Postal Service has issued self-adhesive stamps that may be difficult to separate from envelopes via the traditional method of soaking in water. Heptane-based products like Bestine, as well as limonene-based products, are alternative solvents for removing stamps more easily.

 مقياس تصنيف الأوكتان

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.

 المتصاوغات والمتصاوغات المرآتية

المقالة الرئيسية: C7H16

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

• Heptane (n-heptane), H
  3C−CH
  2−CH
  2−CH
  2−CH
  2−CH
  2−CH
  3
• 2-Methylhexane (isoheptane), H
  3C−CH(CH
  3)−CH
  2−CH
  2−CH
  2−CH
  3
• 3-Methylhexane, H
  3C−CH
  2−C*
  H(CH
  3)−CH
  2−CH
  2−CH
  3 (chiral)
• 2,2-Dimethylpentane (neoheptane), H
  3C−C(CH
  3)
  2−CH
  2−CH
  2−CH
  3
• 2,3-Dimethylpentane, H
  3C−CH(CH
  3)−C*
  H(CH
  3)−CH
  2−CH
  3 (chiral)
• 2,4-Dimethylpentane, H
  3C−CH(CH
  3)−CH
  2−CH(CH
  3)−CH
  3
• 3,3-Dimethylpentane, H
  3C−CH
  2−C(CH
  3)
  2−CH
  2−CH
  3
• 3-Ethylpentane, H
  3C−CH
  2−CH(CH
  2CH
  3)−CH
  2−CH
  3
• 2,2,3-Trimethylbutane, H
  3C−C(CH
  3)
  2−CH(CH
  3)−CH
  3, also known as pentamethylethane and triptane.

 التحضير

The linear n-heptane can be obtained from Jeffrey pine oil. 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.

 المخاطر الصحية

Acute exposure to heptane vapors can cause dizziness, stupor, incoordination, loss of appetite, nausea, dermatitis, chemical pneumonitis, unconsciousness, or possible peripheral neuropathy.

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. Prolonged exposure can also lead to skin dryness or cracking, since the substance defats skin.

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.

 وصلات خارجية

• شهادة بيانات أمان المواد – هيبتان
• هيبتان
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