Nitrous oxide

Nitrous oxide, also known as dinitrogen oxide or dinitrogen monoxide, is a chemical compound with chemical formula N₂O. Under room conditions, it is a colourless non-flammable gas, with a pleasant, slightly-sweet odor. It is commonly known as laughing gas due to the exhilarating effects of inhaling it, and because it can cause spontaneous laughter in some people; it's also known as NOS or nitrous in racing and motorsports, where its usage is widespread. It is used in surgery and dentistry for its anaesthetic and analgesic effects. Nitrous oxide is present in the atmosphere where it acts as a powerful greenhouse gas.

Chemistry

The structure of the nitrous oxide molecule is a linear chain of a nitrogen atom bound to a second nitrogen, which in turn is bound to an oxygen atom. It can be considered a resonance hybrid of

Nitrous oxide [[N₂O]] should not be confused with the other nitrogen oxides such as nitric oxide NO and nitrogen dioxide NO₂.

Note that nitrous oxide is isoelectric with carbon dioxide.

Nitrous oxide can be prepared by heating ammonium nitrate in the laboratory.

Nitrous oxide can be used to nitrites by mixing it with boiling alkali metals, and to oxidize organic compounds at high temperatures.

The CAS number of nitrous oxide is 10024-97-2 and its UN number is 1070.

History

The gas was discovered by Joseph Priestley in 1772. Humphry Davy in the 1790s tested the gas on himself and some of his friends, including the poets Samuel Taylor Coleridge and Robert Southey. They soon realised that nitrous oxide considerably dulled the sensation of pain, even if the inhaler were still semi-conscious. And so it came into use as an anaesthetic, particularly by dentists, who do not typically have access to the services of an anesthesiologist and who may benefit from a patient who can respond to verbal commands.

Uses

Inhalant effects — laughing gas

Nitrous oxide (N₂O) is a dissociative that can cause analgesia, euphoria, dizziness, flanging of sound, and, in some cases, slight hallucinations and mild aphrodisiac effect. It can also result in mild nausea or lingering dizziness if too much is inhaled in too short a time.

During the 19th century, William James and many contemporaries found that inhalation of nitrous oxide resulted in a powerful spiritual and mystical experience for the user. James claimed to experience the fusing of dichotomies into a unity and a revelation of ultimate truth during the inhalation of nitrous oxide. Memory of this experience, however, quickly faded and any attempt to communicate was difficult at best.

The drug currently enjoys moderate popularity in the United States psychedelic community as an inhalant. It was often sold at Grateful Dead and Phish concerts. One slang term for the drug is Hippie Crack; this term implies commentary on the typical user of the substances as well as purported similarities between its psychological addiction potential or the short-lived duration of its effects and similar properties of "crack" cocaine.

The recreational use of nitrous oxide is restricted in many districts. In California, for instance, inhalation of nitrous oxide "for the purpose of causing euphoria, or for the purpose of changing in any manner, one’s mental processes," is a criminal offense under its criminal code Cal. Pen. Code, Sec. 381b.) The Centre for Cognitive Liberty and Ethics, a nonprofit law and policy center in the United States, contends that such laws are unconstitutional "prior restraints on speech" and constitute "cognitive censorship."

Since nitrous oxide can cause dizziness, dissociation, and temporary loss of motor control, it is unsafe to inhale while standing up. Inhalation of nitrous oxide directly from a whipped cream charger or a tank poses serious health risks, as it can cause the lungs to collapse from high levels of pressure, forcing air into the chest cavity, and can cause frostbite since the gas is very cold when released. For those reasons, most recreational nitrous oxide users will discharge the gas into a balloon before inhaling.

While the pure gas itself is not toxic, death can result if it is inhaled in such a way that not enough oxygen is breathed in. Long-term use in large quantities has been associated with dangerous symptoms similar to vitamin B12 deficiency: anemia due to reduced hemopoiesis, neuropathy, tinnitus, and numbness in extremities. In chronic use it is also teratogenic, and foetotoxic. It can be habit-forming, mainly because of its short-lived effect (generally from 1 - 5 minutes in recreational doses) and ease of access. Inhaling industrial-grade nitrous oxide is also dangerous, as it contains many impurities and is not intended for use on humans. Finally, nitrous oxide should not be confused with nitric oxide, an extremely poisonous gas.

Medicine

the nitrous oxide is a very strong analgesic and a week mixture o it with oxygen is used in operation.n NOTE""""----IT does not produce laughing fits-------"""""" general anesthetic, and is generally not used alone in anaesthesia. However, it has a very low short-term toxicity and is an excellent analgesic, so a 50/50 mixture of nitrous oxide and oxygen ("gas and air", supplied under the trade name Entonox) is commonly used during childbirth, for dental procedures, and in emergency medicine.

In general anesthesia it is often used in an 2:1 ratio with oxygen in addition to more powerful general anaesthetic agents such as sevoflurane or desflurane. Its lower solubility in blood means it has a very rapid onset and offset.

It has a MAC of 105% and a blood:gas partition coefficient of 0.46. Less than 0.004% is metabolised in humans.

Nitrous Oxide is liquid at approximately 760 psi at room temperature, and is usually stored and shipped as a self-pressurized liquid.

Aerosol propellant

The gas is licensed for use as a food additive, specifically as an aerosol spray propellant. Its most common uses in this context are in aerosol whipped cream canisters and as an inert gas used to displace staleness-inducing oxygen when filling packages of potato chips and other similar snack foods.

The gas is excellently soluble in fatty compounds. In aerosol whipped cream, it is dissolved in the fatty cream until it leaves the can, when it becomes gaseous and thus creates foam. One can easily obtain the propellant by slowly turning the canister upside down (NO SHAKING) and letting all the contents out, leaving you the N2O. However, if one is using the Nitrous for recreational purposes, using N2O straight from a whipped cream can is unadvisable due to the fact that it is frequently cut with certain chemicals that can cause headaches or nausea. There is also usually a negligible amount of N2O in the cans.

Rocket motors

Nitrous oxide can be used as an oxidizer in a rocket engine. This has the advantages over other oxidizers that it is non-toxic and, due to its stability at room temperature, easy to store and relatively safe to carry on a flight.

Nitrous oxide has notably been the oxidizer of choice in several hybrid rocket designs (using solid fuel with a liquid or gaseous oxidizer). The combination of nitrous oxide with hydroxy-terminated polybutadiene fuel has been used by SpaceShipOne and others. It is also notably used in amateur and high power rocketry with various plastics as the fuel. An episode of MythBusters featured a hybrid rocket built using paraffin wax mixed with powdered carbon as its solid fuel and nitrous oxide as its oxidizer.

Internal Combustion Engine

In car racing, nitrous oxide (often just "nitrous" in this context) is sometimes injected into the intake manifold (or just prior to the intake manifold) to increase power: even though the gas itself is not flammable, it delivers more oxygen than atmospheric air by breaking down at elevated temperatures, thus allowing the engine to burn more fuel and air. Additionally, since nitrous oxide is stored as a liquid, the evaporation of liquid nitrous oxide in the intake manifold causes a large drop in intake charge temperature. This results in a smaller, denser charge, and can reduce detonation, as well as increase power available to the engine.

The same technique was used during by World War II Luftwaffe aircraft with the GM 1 system to boost the power output of aircraft engines. Originally meant to provide the Luftwaffe standard aircraft with superior high-altitude performance, technological considerations limited its use to extremely high altitudes. Accordingly, it was only used by specialized planes like high-altitude reconnaissance aircraft, high-speed bombers and high-altitude interceptors.

One of the major problems of using nitrous oxide in a reciprocating engine is that it can produce enough power to destroy the engine. Power increases of 100-300% are possible, and unless the mechanical structure of the engine is reinforced, most engines would not survive this kind of operation.

There are several ways of introducing nitrous into a motor. Nitrous kits such as such as NOS, Nitrous Express, Nitrous Direct brands offer different solutions. You will find Dry kits, Wet kits & Direct port. See nitrous

It is very important with nitrous oxide augmentation of internal combustion engines to maintain temperatures and fuel levels so as to prevent preignition, or detonation (sometimes referred to as knocking, pinging or pinking).

Safety

The major safety hazards of nitrous oxide come from the fact that it is a compressed liquified gas, and a dissociative anaesthetic.

While normally inert in storage and fairly safe to handle, nitrous oxide can decompose energetically and potentially detonate if initiated under the wrong circumstances. Liquid nitrous oxide acts a good solvent for many organic compounds; liquid mixtures can form somewhat sensitive explosives. Contamination with fuels has been implicated in a handful of rocketry accidents, where small quantities of nitrous / fuel mixtures detonated, triggering the explosive decomposition of residual nitrous oxide in plumbing.

Nitrous oxide in the atmosphere

Nitrogen oxides, nitrous oxide included, are greenhouse gases; per kilogram, nitrous oxide has 296 times the effect of carbon dioxide for producing global warming [1]. Therefore, nitrogen oxides are a subject of efforts to curb greenhouse gas emissions, such as the Kyoto Protocol. Behind carbon dioxide and methane, nitrous oxide is the third most important gas that contribute to global warming.

Nitrous oxide is naturally emitted from soils and oceans. Human activity contributes to the release of the gas through the cultivation of soil and the production and use of nitrogen fertilizers, the production of nylon, and the burning of fossil fuels and other organic matter.

Human activity is thought to account for somewhat less than 2 teragrams (this is multiplied by appx 300 when calculated as a ratio to Carbon Dioxide) of nitrogen oxides per year, nature for over 15 teragrams [2].

Legality in the United States

Possession of nitrous oxide is illegal in most localities in the United States for the purposes of inhaling or ingesting if not under the care of a physician or dentist.

Nitrous oxide injection systems for automobiles are usually legal, although the use of a nitrous oxide system is likely to result in speeds that are in violation of other traffic laws. Some localities also require certified system components. There have been numerous reported instances of police officers arresting drivers of vehicles equipped with nitrous oxide injection systems on the grounds that he or she intends to inhale it. However, such auto-grade nitrous oxide is mixed with hydrogen sulfide and would cause significant deleterious effects if inhaled.

Neuropharmacology

Nitrous oxide shares many pharmacological similarities with classical gaseous and intravenous anesthetics, however, there are well-documented unquestionable differences.

Nitrous oxide is relatively non-polar and has a low molecular weight, allowing it to dissolve through fats easily. This makes it effective for propelling whipped cream and also permits the gas to quickly penetrate fatty phospholipid cell membranes. Nitrous oxide diffuses through membranes much faster than any other anesthetic gas, giving it an extremely rapid onset. It is chemically inert at body temperatures, and so it is carried free in the blood rather than binding to hemogloubin.

Like many classical anesthetics, N₂O non-competitively inhibits the NMDA receptor with high affinity and efficacy at concentrations directly proportional to its anaesthetic concentrations (Jevtovic-Todorovic et al., 1998; Mennerick et al., 1998; Yamakura & Harris, 2000). The evidence on the effect of N₂O on GABA-A currents is mixed, but tends to show a lower potency potentiation (Dzoljic & Van Duijn, 1998; Mennerick et al., 1998; Yamakura & Harris, 2000). N₂O, like other volatile anesthetics, activates twin-pore potassium channels, albeit weakly. These channels are largely responsible for keeping neurons at the resting (unexcited) potential (Gruss et al., 2004). Unlike many anesthetics, however, N₂O does not seem to affect calcium channels (Mennerick et al., 1998).

Unlike most general anesthetics, N₂O seems to somehow affect the benzodiazepine receptor. In many behavioral tests of anxiety, low doses of N₂O is a successful anxiolytic. This anti-anxiety effect is partially reversed by benzodiazepine receptor antagonists. Mirroring this, animals which have developed tolerance to the anxiolytic effects of benzodiazepines are partially tolerant to nitrous oxide (Czech & Green, 1992; Emmanouil et al., 1994; Quock et al., 1992). Indeed, in humans given 30% N₂O, benzodiazepine receptor antagonists reduced the subjective reports of feeling “high”, but did not alter psycho-motor performance (Zacny et al., 1995).

Most interestingly, the effects of N₂O seem somehow linked to the interaction between the endogenous opioid system and the descending noradrenergic system. When animals are given morphine chronically they develop tolerance to its antinociceptive (pain killing) effects; this also renders the animals tolerant to the antinocicpetive effects of N₂O (Berkowitz et al., 1979). Administration of antibodies which bind and block the activity of some endogenous opioids (not beta-endorphin) block the antinociceptive effects of N₂O (Branda et al., 2000; Cahill et al., 2000). Drugs which inhibit the breakdown of endogenous opioids also potentiate the antinociceptive effects of N₂O (Branda et al., 2000). Several experiments have shown that opioid receptor antagonists applied directly to the brain block the antinociceptive effects of N₂O, but these drugs have no effect when injected into the spinal cord. Conversely, alpha-adrenoreceptor antagonists block the antinociceptive effects of N₂O when given directly to the spinal cord, but not when applied directly to the brain (Fang et al., 1997; Guo et al., 1999; Guo et al., 1996). Indeed, alpha2B-adrenoreceptor knockout mice or animals depleted in noradrenaline are nearly completely resistant to the antinociceptive effects of N₂O (Sawamura et al., 2000; Zhang et al., 1999). It seems N₂O-induced released of endogenous opioids causes disinhibition of brainstem noradrenergic neurons, which descend into the spinal cord and inhibit pain signaling. Exactly how N₂O causes the release of opioids is still uncertain.

In conclusion, N₂O induces its effects through classical volatile anaesthetic mechanisms like NMDA receptor antagonist, GABA-A potentiation and potassium channel activation as well as novel mechanisms such as a benzodiazepine-like effect and stimulating endogenous opioid receptors.

Laughing Gas in fiction

• Laughing Gas (movie)
• Laughing Gas (novel)
• Laughing Gas is one of the main weapons used by the Batman villain, The Joker, only he uses a concoction which is portrayed as being green and lethal.
• One of the main characters in the musical film version of Little Shop of Horrors dies from the inhalation of Laughing Gas.
• Two of the main characters in Taxi get trapped in a room filled with laughing gas.
• The main character of Zodiac, Sangamon Taylor, uses it as a drug, and even came up with Sangamon's Principle to explain why it should be used over other drugs.
• In Black Sheep, the two main protagonists borrow a police car and its nitrous oxide boosters leak after hitting a pothole, intoxicating the duo.
• In the Munsters episode where Herman sneaks into the hospital to visit Eddie after hours, Herman is given Laughing Gas by the staff.