Ethanol

Description

Ethyl alcohol, also called ethanol, absolute alcohol, or grain alcohol, is a clear, colorless, flammable liquid with a pleasant odor. It is associated primarily with alcoholic beverages, but it has numerous uses in the chemical industry. The word alcohol is derived from the Arabic word al kuhul, which was a fine powder of the element antimony used as a cosmetic. In Medieval times, the word al kuhul came to be associated with the distilled products known as alcohols. The hydroxyl group, -OH, bonded to a carbon, characterizes alcohols. Ethyl is derived from the root of the two-carbon hydrocarbon ethane.

Chemical properties

Ethanol is a clear, colourless liquid with a characteristic pleasant odour and burning taste. It is highly flammable. Ethanol rapidly absorbs water from the air. It mixes readily with most organic liquids.

Chemical properties

Ethyl alcohol is a colorless flammable liquid with a typical lower alcohol odor and is miscible in water in all proportions. It is stable and hygroscopic. It is incompatible with strong oxidizing agents, peroxides, acids, acid chlorides, acid anhydrides, alkali metals, ammonia, and moisture. Ethyl alcohol forms explosive mixtures with air. Ethyl alcohol is the most common solvent used in aerosols, cosmetics, pharmaceuticals, alcoholic beverages, vinegar production, and in the chemical synthesis of a large variety of products in different industries. For instance, in the manufacture of plastics, lacquers, polishes, plasticizers, perfumes, adhesives, rubber accelerators, explosives, synthetic resins, nitrocellulose, inks, preservatives, and as a fuel.

Chemical properties

Ethyl alcohol is a colorless, volatile, flammable liquid with a sweet, fruity odor. The Odor Threshold is 0.135
5 ppm.

Chemical properties

In the BP 2009, the term ‘alcohol’; used without other qualification refers to ethanol containing ≥99.5% v/v of C₂H₆O. The term‘alcohol’, without other qualification, refers to ethanol 95.1–96.9% v/v. Where other strengths are intended, the term ‘alcohol’ or ‘ethanol’is used, followed by the statement of the strength. In the PhEur 6.0, anhydrous ethanol contains not less than 99.5% v/v of C₂H₆O at 208℃. The term ethanol (96%) is used to describe the material containing water and 95.1–96.9% v/v of C₂H₆O at 208℃.

Occurrence

Reported found in apple, apple aroma, apple essence, apple juice, bacon fat, banana, bean, beef fat, beef extract, blackberry, black currant, bread, brussels sprout, cabbage, carrot root, cauliflower, blue cheese, cheddar cheese, Swiss cheese, cocoa bean, cherry, coffee, cream, cucumber, alcoholic beverages and many other sources

History

Alcohol is produced naturally from the fermentation of sugars, and it is assumed that prehistoric humans consumed alcohol when eating fermented fruits. The earliest direct evidence of alcohol consumption dates from the Neolithic period 10,000 years ago and consists of stone jugs used for holding alcoholic beverages. Ancient records and art from Egypt, Babylon, Mesopotamia, and other early civilizations indicate the use of alcohol as a beverage, medicine, and ceremonial drink. Records also show that the intoxicating effects of alcohol were known for thousands of years b.c.e. Alcoholic drinks were stored in Egyptian burial tombs, and deities devoted to alcoholic beverages were worshiped by different civilizations. As the human population expanded, alcoholic drinks assumed a prominent role in different cultures; for example, numerous references are made to wine in the Bible. Ancient Islamic alchemists advanced the practice of alcohol production by using distillation techniques. Distilled alcohols began to appear in the Middle Ages and was used in many remedies and medicines. A common practice by alchemists in different regions was the preparation of special liquors and brews with healing power. Aqua vitae (water of life) could refer to brandy, gin, whiskey, wine, or another form of alcoholic depending on the geographic area.

The Uses of Ethanol

alcohol (alcohol SD-40; alcohol SDA-40; ethanol; ethyl alcohol) is widely used in the cosmetic industry as an antiseptic as well as a solvent given its strong grease-dissolving abilities. It is often used in a variety of concentrations in skin toners for acne skin, aftershave lotions, perfumes, suntan lotions, and toilet waters. Alcohol dries the skin when used in high concentrations. It is manufactured through the fermentation of starch, sugar, and other carbohydrates.

The Uses of Ethanol

Suitable for use in the precipitation of nucleic acids.

The Uses of Ethanol

Most ethyl alcohol is used in alcoholic beverages in suitable dilutions. Other uses are as solvent in laboratory and industry, in the manufacture of denatured alcohol, pharmaceuticals (rubbing Compounds, lotions, tonics, colognes), in perfumery, in organic synthesis. Octane booster in gasoline. Pharmaceutic aid (solvent).

The Uses of Ethanol

ethyl alcohol (Etanol) is commonly known as rubbing alcohol. ethyl alcohol is ordinary alcohol and is used medicinally as a topical antiseptic, astringent, and anti-bacterial. At concentrations above 15 percent, it is also a broad-spectrum preservative against bacteria and fungi, and can boost the efficacy of other preservatives in a formulation. Cosmetic companies tend to use alcohol SD-40 in high-grade cosmetic manufacturing as they consider ethanol too strong and too drying for application on the skin. obtained from grain distillation, it can also be synthetically manufactured.

The Uses of Ethanol

Ethanol is used primarily as a solvent — animportant industrial solvent for resins, lacquers, pharmaceuticals, toilet preparations,and cleaning agents; in the production of rawmaterials for cosmetics, perfumes, drugs, andplasticizers; as an antifreeze; as an automotive fuel additive; and from ancient times, inmaking beverages. Its pathway to the bodysystem is mainly through the consumption ofbeverages. It is formed by the natural fermentation of corn, sugarcane, and other crops.

The Uses of Ethanol

One of the most prominent uses of ethyl alcohol is as a fuel additive and increasingly as a fuel itself. Ethyl alcohol is added to gasoline to increase its oxygen content and octane number. In the United States, the Environmental Protection Agency has mandated that oxygenated fuels be used in certain geographic areas to help meet air quality standards for carbon monoxide, especially in winter. A gasoline blended for this purpose may contain a few percent ethyl alcohol. Gasoline blended with ethyl alcohol is called gasohol. A typical gasohol may contain 90% gasoline and 10% ethanol. Gasohol reduces several common air pollutants including carbon monoxide, carbon dioxide, hydrocarbons, and benzene. Conversely, nitrogen oxides increase with gasohol.

Background

A clear, colorless liquid rapidly absorbed from the gastrointestinal tract and distributed throughout the body. It has bactericidal activity and is used often as a topical disinfectant. It is widely used as a solvent and preservative in pharmaceutical preparations as well as serving as the primary ingredient in alcoholic beverages.

Indications

For therapeutic neurolysis of nerves or ganglia for the relief of intractable chronic pain in such conditions as inoperable cancer and trigeminal neuralgia (tic douloureux), in patients for whom neurosurgical procedures are contraindicated.

Definition

ChEBI: A primary alcohol that is ethane in which one of the hydrogens is substituted by a hydroxy group.

Indications

Ethanol is the most widely abused drug in the world. There are more than 10 million alcoholics in the United States alone. Excessive consumption of alcoholic beverages has been linked to as many as half of all traffic accidents, two-thirds of homicides, and three-fourths of suicides, and it is a significant factor in other crimes, in family problems, and in personal and industrial accidents. The annual cost to the American economy has been estimated to exceed $100 billion in lost productivity, medical care, and property damage.
Alcoholism has been difficult to define because of its complex nature.A person is generally considered an alcoholic, however, when his or her lifestyle is dominated by the procurement and consumption of alcoholic beverages and when this behavior interferes with personal, professional, social, or family relations.
A light drinker generally is defined as one who consumes an average of one drink or less per day, usually with the evening meal; a moderate drinker is one who has approximately three drinks per day; and a heavy drinker is one who has five or more drinks per day (or in the case of binge drinkers, at least once per week with five or more drinks on each occasion).

Indications

Intravenous use of ethanol, while once widely employed to inhibit premature labor, is now of historical interest only. Ethanol inhibits oxytocin release from the pituitary and thus indirectly decreases myometrial contractility. Today, 2-adrenomimetics and magnesium sulfate have replaced ethanol for parenteral tocolysis.

Preparation

There are several approaches to the production of ethanol; mainly ethanol is produced by fermentation.

Production Methods

Ethanol is manufactured by the controlled enzymatic fermentation of starch, sugar, or other carbohydrates. A fermented liquid is produced containing about 15% ethanol; ethanol 95% v/v is then obtained by fractional distillation. Ethanol may also be prepared by a number of synthetic methods.

Definition

A colorless volatile liquid alcohol. Ethanol occurs in intoxicating drinks, in which it is produced by fermentation of a sugar: C₆H₁₂O₆ → 2C₂H₅OH + 2CO₂ Yeast is used to cause the reaction. At about 15% alcohol concentration (by volume) the reaction stops because the yeast is killed. Higher concentrations of alcohol are produced by distillation. Apart from its use in drinks, alcohol is used as a solvent and to form ethanal. Formerly, the main source was by fermentation of molasses, but now catalytic hydration of ethene is used to manufacture industrial ethanol. See also methylated spirits.

brand name

Absolute alcohol;Alcohol aethylicus;Alcool;Avitoin;Banatol;B-tonin;Colfin;Desqyam-x;Duonale-e;Efatin;Equithesin;Hizeneck-d;Honkon-n;Kapsitrin;Keralyt;Levovinizol;Mikrozid;Neotizol;Panoxy;Papette;Piadarn;Polislerol;Protectaderm;Sicol;Sodaphilline;Softa man;Sotracarix;Verucid;Weingeist;Xeracin.

World Health Organization (WHO)

Ethanol has been used throughout recorded history both in a medicinal and a social context. It is currently included in pharmaceutical preparations either as an active or inactive ingredient. At pharmacologically active doses ethanol is both a powerful cerebral depressant and a drug of addiction. Its use in pharmaceutical preparations has been severely restricted in several countries and in 1986 the 39th World Health Assembly adopted a resolution to prohibit such use except when ethanol is an essential ingredient which cannot be replaced by an appropriate alternative.

Aroma threshold values

Detection: 8 to 900 ppb

General Description

Reagent Alcohol is denatured alcohol that consists of ethanol, isopropyl alcohol and methyl alcohol in the ratio 90:5:5.

Reactivity Profile

It liberates hydrogen when it reacts withmetal; forms acetaldehyde (toxic, flammable)on catalytic vapor phase dehydrogenation;ethyl ether (flammable) on dehydration withH2SO4 or a heterogeneous catalyst such asalumina, silica, SnCl2, MnCl2, or CuSO4;.

Hazard

Classified as a depressant drug. Though it is rapidly oxidized in the body and is therefore noncumulative, ingestion of even moderate amounts causes lowering of inhibitions, often succeeded by dizziness, headache, or nausea. Larger intake causes loss of m

Health Hazard

The toxicity of ethanol is much lower thanthat of methanol or propanol. However, theliterature on the subject is vastly greater thanthat of any other alcohol. This is attributableessentially to its use in alcoholic beverages.There are exhaustive reviews on alcohol toxicity and free-radical mechanisms (Nordmannet al. 1987). The health hazard arises primarily from ingestion rather than inhalation. Ingestion of a large dose, 250–500 mL,can be fatal. It affects the central nervoussystem. Symptoms are excitation, intoxication, stupor, hypoglycemia, and coma — thelatter occurring at a blood alcohol contentof 300–400 0 mg/L. It is reported to have atoxic effect on the thyroid gland (Hegeduset al. 1988) and to have an acute hypotensiveaction, reducing the systolic blood pressurein humans (Eisenhofer et al. 1987). Chronicconsumption can cause cirrhosis of the liver.Inhalation of alcohol vapors can result inirritation of the eyes and mucous membranes.This may happen at a high concentrationof 5000–10,000 ppm. Exposure may resultin stupor, fatigue, and sleepiness. There isno report of cirrhosis occurring from inhalation. Chronic exposure to ethanol vapors hasproduced brain damage in mice. The neurotoxicity increases with thiamine deficiency(Phillips 1987). Both acute and chronic dosesof ethanol elevated the lipid peroxidation inrat brain. This was found to be elevated further by vitamin E deficiency, as well as itssupplementation (Nadiger et al. 1988).
pplementation (Nadiger et al. 1988).The toxicity of ethanol is enhanced in thepresence of compounds such as barbiturates,carbon monoxide, and methyl mercury. Withthe latter compound, ethanol enhanced theretention of mercury in the kidney of ratsand thus increased nephrotoxicity (McNeilet al. 1988). When combined with cocaineand fed to rats, increased maternal and fetaltoxicity was observed (Church et al. 1988).Ethanol is reported to be synergisticallytoxic with caffeine (Pollard 1988) andwith n-butanol and isoamyl alcohol. Priorethanol consumption increased the toxicity of acetaminophen in mice (Carter1987).

Flammability and Explosibility

Ethanol is a flammable liquid (NFPA rating = 3), and its vapor can travel a considerable distance to an ignition source and "flash back." Ethanol vapor forms explosive mixtures with air at concentrations of 4.3 to 19% (by volume). Hazardous gases produced in ethanol fires include carbon monoxide and carbon dioxide. Carbon dioxide or dry chemical extinguishers should be used for ethanol fires.

Chemical Reactivity

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

Pharmaceutical Applications

Ethanol and aqueous ethanol solutions of various concentrations are widely used in pharmaceutical formulations and cosmetics. Although ethanol is primarily used as a solvent, it is also employed as a disinfectant, and in solutions as an antimicrobial preservative. Topical ethanol solutions are used in the development of transdermal drug delivery systems as penetration enhancers. Ethanol has also been used in the development of transdermal preparations as a co-surfactant.

Toxicity

Oral, rat LD50: 5628 mg/kg. Symptoms and effects of overdose include nausea, vomiting, CNS depression, acute respiratory failure or death and with chronic use, severe health problems, such as liver and brain damage.

Contact allergens

Ethanol is widely used for its solvent and antiseptic properties. It is rather an irritant and sensitization has rarely been reported.

Biochem/physiol Actions

Positive allosteric modulator of GABAA receptors, and negative allosteric modulator of NMDA glutamate receptors.

Mechanism of action

A great deal of attention has been focused on a class of proteins termed the ligand-gated ion channels as being important to the mechanism of action of alcohol.These integral membrane proteins function as gates or pores that allow the passage of certain ions into and out of neurons upon binding of the appropriate neurotransmitter. This flux of ions largely determines the degree of neuronal activity. Two distinct types of ligand-gated ion channels are particularly sensitive to concentrations of alcohol that produce intoxication and sedation. These are the α-aminobutyric acid (GABA) chloride ionophore and the N-methyl-D-aspartate (NMDA) subtype of glutamate receptor. The GABA–chloride ion channel reduces neuronal activity by hyperpolarizing the neurons, while activation of the NMDA receptor causes neuronal depolarization or excitation. Alcohol has been shown to increase chloride flux through the GABAA receptor and reduce calcium flux through the NMDA receptor. These actions result in powerful suppression of nerve cell activity, which is consistent with the depressant actions of alcohol in the brain.

Pharmacokinetics

Alcohol produces injury to cells by dehydration and precipitation of the cytoplasm or protoplasm. This accounts for its bacteriocidal and antifungal action. When alcohol is injected in close proximity to nerve tissues, it produces neuritis and nerve degeneration (neurolysis). Ninety to 98% of ethanol that enters the body is completely oxidized. Ethanol is also used as a cosolvent to dissolve many insoluble drugs and to serve as a mild sedative in some medicinal formulations. Ethanol also binds to GABA, glycine, NMDA receptors and modulates their effects. Ethanol is also metabolised by the hepatic enzyme alcohol dehydrogenase.

Clinical Use

Generally, no treatment is required for acute ethanol intoxication. Allowing the individual to sleep off the effects of ethanol ingestion is the usual procedure. Hangovers are treated similarly; that is, no effective remedy exists for a hangover, except for controlling the amount of ethanol consumed. Sometimes ethanol overdose is a medical emergency. For example, prompt treatment is required if the patient is in danger of dying of respiratory arrest, is comatose, has dilated pupils, is hypothermic, or displays tachycardia.
Treatment for severe ethanol overdose is generally supportive. Increased intracranial pressure can be relieved by intravenous administration of hypertonic mannitol. Hemodialysis can accelerate the removal of ethanol from the body. Stimulants of ethanol metabolism, such as fructose, are not sufficiently effective, and use of analeptics is not recommended because of the possibility of precipitating convulsions.
The immediate concern in the treatment of alcoholics is detoxification and management of the ethanol withdrawal syndrome. Another pharmacological approach is the use of anticraving drugs, for example serotonin uptake inhibitors,dopaminergic agonists, and opioid antagonists.The only treatment that has shown considerable promise is one that uses the opioid antagonist naltrexone.

Absorption

Rapidly absorbed.

Side Effects

Acute Ethanol Intoxication and Hangover
Ethanol intoxication is probably the best-known form of drug toxicity. Intoxicated individuals are a threat to themselves and others, particularly if they attempt to drive or operate machinery. Although death can result from ethanol overdose, usually the patient lapses into a coma before ingesting lethal quantities. Ethanol intoxication is sometimes mistakenly diagnosed as diabetic coma, schizophrenia, overdosage of other CNS depressant drugs, or skull fracture. An additional feature commonly associated with excessive ethanol consumption is difficulty in regulating body temperature. Hypothermia frequently results, with body temperature falling toward that of the ambient environment. This problem can be particularly severe in the elderly, who normally have difficulty regulating their body temperature.
One of the consequences of ethanol intoxication is the hangover, a condition characterized by headache, nausea, sweating, and tremor. Although unpleasant, a hangover is not dangerous, even though the person having one may feel otherwise.

Safety Profile

Confirmed human carcinogen for ingestion of beverage alcohol. Experimental tumorigenic and teratogenic data. Moderately toxic to humans by ingestion. Moderately toxic experimentally by intravenous and intraperitoneal routes. Mildly toxic by inhalation and skin contact. Human systemic effects by ingestion and subcutaneous routes: sleep disorders, hallucinations, dtstorted perceptions, convulsions, motor activity changes, ataxia, coma, antipsychotic,headache, pulmonary changes, alteration in gastric secretion, nausea or vomiting, other gastrointestinal changes, menstrual cycle changes, and body temperature decrease. Can also cause glandular effects in humans. Human reproductive effects by ingestion, intravenous, and intrauterine routes: changes in female fertility index. Effects on newborn include: changes in Apgar score, neonatal measures or effects, and drug dependence. Experimental reproductive effects. Human mutation data reported. An eye and skin irritant. The systemic effect of ethanol differs from that of methanol. Ethanol is rapidly oxidtzed in the body to carbon dtoxide and water, and, in contrast to methanol, no cumulative effect occurs. Though ethanol possesses narcotic properties, concentrations sufficient to produce this effect are not reached in industry. Concentrations below 1000 pprn usually produce no signs of intoxication. Exposure to concentrations over 1000 pprn may cause headache, irritation of the eyes, nose, and throat, and, if continued for an hour, drowsiness and lassitude, loss of appetite, and inability to concentrate. There is no concrete evidence that repeated exposure to ethanol vapor results in cirrhosis of the liver. Ingestion of large doses can cause alcohol poisoning. Repeated ingestions can lead to alcoholism. It is a central nervous system depressant.Flammable liquid when exposed to heat or flame; can react vigorously with oxidizers. To fight fire, use alcohol foam, CO2, dry chemical. Explosive reaction with the oxidized coating around potassium metal. Ignites and then explodes on contact with acetic anhydride + sodum hydrogen sulfate. Reacts violently with acetyl bromide (evolves hydrogen bromide), dichloromethane + sulfuric acid + nitrate or nitrite, disulfuryl difluoride, tetrachlorosilane + water, and strong oxidants. Ignites on contact with disulfuric acid + nitric acid, phosphorus(IⅡ) oxide, platinum, potassium tert-butoxide + acids. Forms explosive products in reaction with ammonia + silver nitrate (forms silver nitride and silver fulminate), magnesium perchlorate (forms ethyl perchlorate), nitric acid + silver (forms silver fulminate), silver nitrate (forms ethyl nitrate), silverp) oxide + ammonia or hydrazine (forms silver nitride and silver fulminate), sodum (evolves hydrogen gas). Incompatible with acetyl chloride, BrF5, Ca(OCl)2, ClO3, Cr03, Cr(OCl)2, (cyanuric acid + H20), H202, HNO3, (H202 + H2SO4), (I + CH3OH + HgO), wn(ClO4)2 + 2,2-dimethoxy propane], Hg(NO3)2, HClO4, perchlorates, (H2SO4 + permanganates), HMn04, KO2, KOC(CH3)3, AgClO4, NaH3N2, uo2(clO4)2

Safety

Ethanol and aqueous ethanol solutions are widely used in a variety of pharmaceutical formulations and cosmetics. It is also consumed in alcoholic beverages.
Ethanol is rapidly absorbed from the gastrointestinal tract and the vapor may be absorbed through the lungs; it is metabolized, mainly in the liver, to acetaldehyde, which is further oxidized to acetate.
Ethanol is a central nervous system depressant and ingestion of low to moderate quantities can lead to symptoms of intoxication including muscle incoordination, visual impairment, slurred speech, etc. Ingestion of higher concentrations may cause depression of medullary action, lethargy, amnesia, hypothermia, hypoglycemia, stupor, coma, respiratory depression, and cardiovascular collapse. The lethal human blood-alcohol concentration is generally estimated to be 400–500 mg/100 mL.
Although symptoms of ethanol intoxication are usually encountered following deliberate consumption of ethanol-containing beverages, many pharmaceutical products contain ethanol as a solvent, which, if ingested in sufficiently large quantities, may cause adverse symptoms of intoxication. In the USA, the maximum quantity of alcohol included in OTC medicines is 10% v/v for products labeled for use by people of 12 years of age and older, 5% v/v for products intended for use by children aged 6–12 years of age, and 0.5% v/v for products for use by children under 6 years of age.
Parenteral products containing up to 50% of alcohol (ethanol 95 or 96% v/v) have been formulated. However, such concentrations can produce pain on intramuscular injection and lower concentrations such as 5–10% v/v are preferred. Subcutaneous injection of alcohol (ethanol 95% v/v) similarly causes considerable pain followed by anesthesia. If injections are made close to nerves, neuritis and nerve degeneration may occur. This effect is used therapeutically to cause anesthesia in cases of severe pain, although the practice of using alcohol in nerve blocks is controversial. Doses of 1mL of absolute alcohol have been used for this purpose.
Preparations containing more than 50% v/v alcohol may cause skin irritation when applied topically.
LD₅₀ (mouse, IP): 0.93 g/kg
LD₅₀ (mouse, IV): 1.97 g/kg
LD₅₀ (mouse, oral): 3.45 g/kg
LD₅₀ (mouse, SC): 8.29 g/kg
LD₅₀ (rat, IP): 3.75 g/kg
LD₅₀ (rat, IV): 1.44 g/kg
LD₅₀ (rat, oral): 7.06 g/kg

Potential Exposure

Ethyl alcohol is used, topical antiinfective agent; solvent to make beverages; in the chemical synthesis of a wide variety of compounds, such as acetaldehyde, ethyl ether, ethyl chloride, and butadiene. It is a solvent or processing agent in the manufacture of pharmaceuticals; plastics, lacquers, polishes, plasticizers, perfumes, cosmetics, rubber accelerators; explosives, synthetic resins; nitrocellulose, adhesives, inks, and preservatives. It is also used as an antifreeze and as a fuel. It is an intermediate in the manufacture of many drugs and pesticides.

First aid

If this chemical gets into the eyes, remove anycontact lenses at once and irrigate immediately for at least15 min, occasionally lifting upper and lower lids. Seekmedical attention immediately. If this chemical contacts theskin, remove contaminated clothing and wash immediatelywith soap and water. Seek medical attention immediately.If this chemical has been inhaled, remove from exposure,begin rescue breathing (using universal precautions, including resuscitation mask) if breathing has stopped and CPRif heart action has stopped. Transfer promptly to a medicalfacility. When this chemical has been swallowed, getmedical attention. Give large quantities of water andinduce vomiting. Do not make an unconscious personvomit.

Carcinogenicity

In 1987, the International Agency for Research on Cancer (IARC) evaluated the cancer data on ethanol and alcoholic beverages in humans and animals . The IARC concluded that there was inadequate evidence for the carcinogenicity of ethanol and of alcoholic beverages in experimental animals, but there was sufficient evidence for the carcinogenicity of alcoholic beverages in humans. The IARC classified alcoholic beverages as a Group 1 carcinogen based on the occurrence of malignant tumors of the oral cavity, pharynx, larynx, esophagus, and liver that have been causally related to the consumption of alcoholic beverages.

Environmental Fate

If released to the environment from natural or anthropogenic sources, ethanol will preferentially partition to the soil, water, and air. Bioconcentration and bioaccumulation potential is anticipated to be low based upon the estimated bioconcentration factor and experimental octanol/water partition coefficient. If released into water, ethanol’s half-life is less than 10 days. The half-life upon release to air is less than 5 days, where wet deposition removal predominates. Biodegradation and volatilization are expected to be important fate and transport processes for ethanol.

Metabolism

Hepatic. Metabolized by cytochrome P450 enzyme CYP2E1.

storage

Ethyl alcohol should be protected from physical damage. It should be kept stored in a cool, dry, well-ventilated location, away from any area where the fi re hazard may be acute. Outside or detached storage is preferred. Separate from incompatibles. Containers should be bonded and grounded for transfer to avoid static sparks. The storage and use areas should be free from smoking areas.

Shipping

UN1170 Ethyl alcohol or Ethanol or Ethanol solutions or Ethyl alcohol solutions, Hazard Class: 3; Labels: 3-Flammable liquid.

Purification Methods

Usual impurities of fermentation alcohol are fusel oils (mainly higher alcohols, especially pentanols), aldehydes, esters, ketones and water. With synthetic alcohol, likely impurities are water, aldehydes, aliphatic esters, acetone and diethyl ether. Traces of *benzene are present in ethanol that has been dehydrated by azeotropic distillation with *benzene. Anhydrous ethanol is very hygroscopic. Water (down to 0.05%) can be detected by formation of a voluminous precipitate when aluminium ethoxide in *benzene is added to a test portion, Rectified spirit (95% ethanol) is converted to absolute (99.5%) ethanol by refluxing with freshly ignited CaO (250g/L) for 6hours, standing overnight and distilling with precautions to exclude moisture. Numerous methods are available for further drying of absolute ethanol for making “Super dry ethanol”. Lund and Bjerrum [Chem Ber 64 210 1931] used reaction with magnesium ethoxide, prepared by placing 5g of clean dry magnesium turnings and 0.5g of iodine (or a few drops of CCl4), to activate the Mg, in a 2L flask, followed by 50-75 mL of absolute ethanol, and warming the mixture until a vigorous reaction occurs. When this subsides, heating is continued until all the magnesium is converted to magnesium ethoxide. Up to 1L of ethanol is then added and, after an hour's reflux, it is distilled off. The water content should be below 0.05%. Walden, Ulich and Laun [Z Phys Chem 114 275 1925] used amalgamated aluminium chips, prepared by degreasing aluminium chips (by washing with Et2O and drying in a vacuum to remove grease from machining the Al), treating with alkali until hydrogen evolved vigorously, washing with H2O until the washings were weakly alkaline and then stirring with 1% HgCl2 solution. After 2minutes, the chips were washed quickly with H2O, then alcohol, then ether, and dried with filter paper. (The amalgam became warm.) These chips were added to the ethanol, which was then gently warmed for several hours until evolution of hydrogen ceased. The alcohol was distilled and aspirated for some time with pure dry air. Smith [J Chem Soc 1288 1927] reacted 1L of absolute ethanol in a 2L flask with 7g of clean dry sodium, and added 25g of pure ethyl succinate (27g of pure ethyl phthalate was an alternative), and refluxed the mixture for 2hours in a system protected from moisture, and then distilled the ethanol. A modification used 40g of ethyl formate instead, so that sodium formate separated out and, during reflux, the excess of ethyl formate decomposed to CO and ethanol. Drying agents suitable for use with ethanol include Linde type 4A molecular sieves, calcium metal, and CaH2. The calcium hydride (2g) is crushed to a powder and dissolved in 100mL absolute ethanol by gently boiling. About 70mL of the ethanol are distilled off to remove any dissolved gases before the remainder is poured into 1L of ca 99.9% ethanol in a still, where it is boiled under reflux for 20hours, while a slow stream of pure, dry hydrogen (better use nitrogen or Ar) is passed through. It is then distilled [Rüber Z Elektrochem 29 334 1923]. If calcium is used for drying, about ten times the theoretical amount should be used, and traces of ammonia (from some calcium nitride in the Ca metal) would be removed by passing dry air into the vapour during reflux. Ethanol can be freed from traces of basic materials by distillation from a little 2,4,6-trinitrobenzoic acid or sulfanilic acid. *Benzene can be removed by fractional distillation after adding a little water (the *benzene/water/ethanol azeotrope distils at 64.9o), the alcohol is then re-dried using one of the methods described above. Alternatively, careful fractional distillation can separate *benzene as the *benzene/ethanol azeotrope (b 68.2o). Aldehydes can be removed from ethanol by digesting with 8-10g of dissolved KOH and 5-10g of aluminium or zinc per L, followed by distillation. Another method is to heat under reflux with KOH (20g/L) and AgNO3 (10g/L) or to add 2.5-3g of lead acetate in 5mL of water to 1L of ethanol, followed (slowly and without stirring) by 5g of KOH in 25mL of ethanol: after 1hour the flask is shaken thoroughly, then set aside overnight before filtering and distilling. The residual water can be removed by standing the distillate over activated aluminium amalgam for 1 week, then filtering and distilling. Distillation of ethanol from Raney nickel eliminates catalyst poisons. Other purification procedures include pre-treatment with conc H2SO4 (3mL/L) to eliminate amines, and with KMnO4 to oxidise aldehydes, followed by refluxing with KOH to resinify aldehydes, and distilling to remove traces of H3PO4 and other acidic impurities after passage through silica gel, and drying over CaSO4. Water can be removed by azeotropic distillation with dichloromethane (azeotrope boils at 38.1o and contains 1.8% water) or 2,2,4-trimethylpentane. [Beilstein 1 IV 1289.] Rapid purification: Place degreased Mg turnings (grease from machining the turnings is removed by washing with dry EtOH then Et2O, and drying in a vacuum) (5g) in a dry 2L round bottomed flask fitted with a reflux condenser (protect from air with a drying tube filled with CaCl2 or KOH pellets) and flush with dry N2. Then add iodine crystals (0.5g) and gently warm the flask until iodine vapour is formed and coats the turnings. Cool, then add EtOH (50mL) and carefully heat to reflux until the iodine disappears. Cool again then add more EtOH (to 1L) and reflux under N2 for several hours. Distil and store over 3A molecular sieves (pre-heated at

Toxicity evaluation

Upon acute exposure ethanol is a central nervous system (CNS) depressant that initially and selectively depresses some of the most active portions of the brain (reticular activity system and cortex). The mechanism of action most likely involves interference with ion transport at the axonal cell membrane rather than at the synapse, similar to the action of other anesthetic agents. Ethanol can bind directly to the gamma-aminobutyric acid receptor in the CNS and cause sedative effects. Ethanol may also have direct effects on cardiac muscle, thyroid tissue, and hepatic tissue.
Chronic and excessive ethanol ingestion has been associated with a wide range of adverse effects. At the cellular level these effects can be attributable to metabolic intermediates. Ethanol is metabolized differently at low and high concentrations. At low ethanol blood levels ethanol is metabolized very efficiently by alcohol dehydrogenase to acetaldehyde and then by aldehyde dehydrogenase to acetate producing nicotinamide adenine dinucleotide (NADH) in both reactions.
Chronic high ethanol intake induces the cytochrome P450 mediated MEOS, which can be predominant. Under these conditions ethanol is metabolized to acetaldehyde without reducing NADH. The MEOS pathway utilizes nicotinamide adenine dinucleotide phosphate thus producing an oxidative environment, which decreases the reducing equivalents present in the cell, increasing oxidative stress. This pathway has been associated with the release of highly reactive oxygen species in addition to acetaldehyde, which contributes to the hepatic damage observed in chronic alcohol abuse.
Acetaldehyde has been implicated as one significant contributor to the toxicity observed in chronic ethanol overexposure (see Acetaldehyde). Acetaldehyde is highly reactive and can interact with DNA and proteins to form stable adducts. These DNA adducts may induce mutations, although there is an absence of direct evidence that they are in fact the initiators of cancers associated with alcohol ingestion. Acetaldehyde and malondialdehyde, a product of ethanol-induced lipid peroxidation, can form protein adducts which have been found in the serum of alcoholics and rats fed ethanol. These adducts are capable of eliciting an immune response believed to be important in the inflammatory processes observed in alcoholic liver disease and possibly neurotoxicity.

Incompatibilities

In acidic conditions, ethanol solutions may react vigorously with oxidizing materials. Mixtures with alkali may darken in color owing to a reaction with residual amounts of aldehyde. Organic salts or acacia may be precipitated from aqueous solutions or dispersions. Ethanol solutions are also incompatible with aluminum containers and may interact with some drugs.

Waste Disposal

Dissolve or mix the material with a combustible solvent and burn in a chemical incinerator equipped with an afterburner and scrubber. All federal, state, and local environmental regulations must be observed. Consult with environmental regulatory agencies for guidance on acceptable disposal practices. Generators of waste containing this contaminant (≥100 kg/mo) must conform with EPA regulations governing storage, transportation, treatment, and waste disposal.

Precautions

During handling of ethyl alcohol, workers should use chemical-resistant shields, monogoggles, proper gloves, laboratory coat/apron, and protective equipment as required. Workers and the workplace should have adequate ventilation vent hoods, class b extinguisher. Workers should avoid sources of heat, sparks, or flames. Waste disposal and spill should be collected in suitable containers or absorbed on a suitable absorbent material for subsequent disposal. Waste material should be disposed of in an approved incinerator or in a designated landfi ll site, in compliance with all federal, provincial, and local government regulations.

Regulatory Status

Included in the FDA Inactive Ingredients Database (dental preparations; inhalations; IM, IV, and SC injections; nasal and ophthalmic preparations; oral capsules, solutions, suspensions, syrups, and tablets; rectal, topical, and transdermal preparations). Included in the Canadian List of Acceptable Non-medicinal Ingredients. Included in nonparenteral and parenteral medicines licensed in the UK.