page_title: Nicotine
section_title: Chemistry
hierarchical_section_title: Nicotine / Chemistry
caption_attribution_description: English: Protonated nicotine and deprotonated benzoic acid form a salt. This figure was created using Smi2Depict, with the SMILE descriptor "C[NH+]1CCCC1C2=CN=CC=C2.C1=CC=C(C=C1)C(=O)[O-]".
context_page_description: Nicotine is a widely used stimulant and potent parasympathomimetic alkaloid that is naturally produced in the nightshade family of plants. It is used for smoking cessation to relieve withdrawal symptoms. Nicotine acts as a receptor agonist at most nicotinic acetylcholine receptors, except at two nicotinic receptor subunits where it acts as a receptor antagonist.
  Nicotine constitutes approximately 0.6–3.0% of the dry weight of tobacco. Nicotine is also present at concentrations of millionths of a percent in the edible family Solanaceae, including potatoes, tomatoes, and eggplants, though sources disagree on whether this has any biological significance to human consumers. It functions as an antiherbivore chemical; consequently, nicotine was widely used as an insecticide in the past, and neonicotinoids, such as imidacloprid, are widely used.
  Nicotine is highly addictive, unless used in slow-release forms. An average cigarette yields about 2 mg of absorbed nicotine.
  Higher doses can be fatal. Nicotine addiction involves drug-reinforced behavior, compulsive use, and relapse following abstinence.
context_section_description: Nicotine is a hygroscopic, colorless to yellow-brown, oily liquid, that is readily soluble in alcohol, ether or light petroleum. It is miscible with water in its neutral amine base form between 60 °C and 210 °C. It is a dibasic nitrogenous base, having Kb1=1×10⁻⁶, Kb2=1×10⁻¹¹. It readily forms ammonium salts with acids that are usually solid and water-soluble. Its flash point is 95 °C and its auto-ignition temperature is 244 °C. Nicotine is readily volatile (vapor pressure 5.5 ㎩ at 25 ℃) On exposure to ultraviolet light or various oxidizing agents, nicotine is converted to nicotine oxide, nicotinic acid (niacin, vitamin B3), and methylamine.
  
  Nicotine is optically active, having two enantiomeric forms. The naturally occurring form of nicotine is levorotatory with a specific rotation of [α]D=–166.4° ((−)-nicotine). The dextrorotatory form, (+)-nicotine is physiologically less active than (−)-nicotine. (−)-nicotine is more toxic than (+)-nicotine. The salts of (+)-nicotine are usually dextrorotatory; this conversion between levorotatory and dextrorotatory upon protonation is common among alkaloids. The hydrochloride and sulfate salts become optically inactive if heated in a closed vessel above 180 °C. Anabasine is a structural isomer of nicotine, as both compounds have the molecular formula C₁₀H₁₄N₂. 
  Pod mod electronic cigarettes use nicotine in the form of a protonated nicotine, rather than free-base nicotine found in earlier generations.
caption: Structure of protonated nicotine (left) and structure of the counterion benzoate (right). This combination is used in some vaping products to increase nicotine delivery to the lung.
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