Introduction
There are occasions when things that appear to be very similar are quite different. Both ethanol and methanol fall within this category. These two chemicals look the same if you put them in two different glasses, in addition to sounding similar. However, if you tried anything else with them—even getting too close to the open glasses—you would quickly realize that ethanol and methanol differ significantly from one another and that mistaking one for the other can be disastrous.
In this article, let’s understand the basic differences between ethanol and methanol.
Ethanol vs Methanol
The primary distinction between ethanol and methanol is that the former is edible alcohol that is also used in beverages, whilst the latter is a non-edible solvent, fuel, and antifreeze. While ethanol is a naturally occurring byproduct of plant fermentation and is produced by the hydration of the plant hormone ethylene, methanol is very combustible and volatile.
Now, both non-toxic and biodegradable is ethanol. It is not combustible and doesn't injure if it spills in any way. The chemical name for ethanol is C2H5OH. So basically, alcohol is a clear, colorless liquid with a sharp flavor and vinous aroma. When one of the hydroxy groups is replaced, ethanol is created from the initial state of ethanol, which is ethane.
While methanol is a volatile liquid, extremely flammable, and poisonous substance. Its chemical formula is CH3OH, and it is also known as methyl alcohol. The colorless liquid known as methanol has a slight sweet-pungent aroma. Methanol, which consists of methyl and an alcohol group, is the most basic aliphatic alcohol in its fundamental state.
Difference Between Ethanol and Methanol in Tabular Form
| Parameters of Comparison | Ethanol | Methanol |
| Basic Structure | It has an ethyl group with 2 carbon atoms. | It contains an ethyl group with only 1 carbon atom. |
| The Toxic Nature | When taken or ingested, it affects the central nervous system and may make one sleepy. | It affects the retina of the eye and can result in permanent blindness; if accidentally consumed, it can also be fatal. |
| Flame | It emits a bright blue flame on lighting up. | It emits a bright yellowish-white flame on lighting up. |
| Production Process | Its produced from yeast or sugar by fermentation. | Its made from chemically processed carbon dioxide, carbon monoxide, and hydrogen. |
| Other Properties | Lacking color and being volatile yet not ignitable by nature. | Inflammable, colorless, and very volatile by nature. |
What is Ethanol?
The chemical molecule ethanol, commonly known as ethyl alcohol, grain alcohol, or alcohol, belongs to the class of organic compounds known as alcohols and has the molecular formula C2H5OH. An essential industrial chemical, ethanol is used as an addition to fuel for automobiles, as a solvent, and in the production of other organic compounds (forming a mixture known as gasohol). So, numerous alcoholic drinks, including beer, wine, and distilled spirits, also contain ethanol as an intoxicating component.
Now, the fermentation of carbohydrates (the process used to make alcoholic beverages) and the hydration of ethylene are the two basic procedures for producing ethanol. By expanding yeast cells, carbohydrates are converted to ethanol during fermentation. Now, sugar crops like beets and sugarcane, as well as grain crops like corn, are the main raw materials fermented for the manufacturing of industrial alcohol (maize). Also, by passing a mixture of ethylene and a significant amount of extra steam over an acidic catalyst at high temperatures and pressures, ethylene is hydrated.
The diluted aqueous solution of ethanol obtained from fermentation or synthetic synthesis must be concentrated using fractional distillation. The mixture with a constant boiling point and 95.6% by weight ethanol can only be produced by direct distillation. The mixture with a constant boiling point can be dehydrated to produce absolute, or anhydrous, alcohol. Usually, ethanol meant for industrial use is denatured—made unfit for consumption—with methanol, benzene, or kerosene.
Pure ethanol has a pleasant ethereal aroma and a burning flavor. It is a colorless, combustible liquid with a boiling point of 78.5 °C [173.3 °F]. Alcohol harms the central nervous system and is poisonous. By suppressing the brain's inhibitory functions, moderate doses relax the muscles and appear to stimulate the body, but greater doses impair coordination and judgment, ultimately leading to coma and death. Some people find it to be an addictive substance, which can cause alcoholism.
At a rate of roughly 15 ml, or about half an ounce, of fluid per hour—which equates to about 100 calories—ethanol is metabolized in the body first to acetaldehyde, then to carbon dioxide and water.
Around 1.5 billion gallons of ethanol are produced annually in the United States, primarily from corn. Other biomass resources will be employed to produce ethanol as the demand for it rises, including municipal solid waste, industrial waste, agricultural and forestry waste, and crops are grown especially for energy.
Technology to turn these feedstocks into ethanol has been developed through research over the last 20 years. Currently, the easily fermentable sugars and starches in grain and food industry wastes are used to make fuel ethanol. New technology will soon make producing ethanol from plant fiber commercially feasible.
It is consequently possible to harvest some of the agricultural and forestry wastes (corn stover, stalks, leaves, and branches) that are now burned or left in the field for biofuel production. Connecting the established corn ethanol sector with the nascent technologies that create ethanol from biomass and agricultural wastes will have numerous advantages.
Ethanol is a flammable liquid, and its explosive vapor concentrations in air vary from 3.3 to 19.0 percent (v/v). However, as long as there is adequate ventilation, flammability is not a significant issue in an industrial setting. This also keeps ethanol from becoming a substantial industrial toxin. According to reports, the substance can be detected by a nose at 350 ppm, but at concentrations of 5000–10,000 ppm, it can irritate the eyes and upper respiratory tract mucous membranes.
Concentrations above these thresholds quickly become unbearable and cause violent coughing and laceration. However, because ethanol is quickly converted to water and carbon dioxide in the body, it is not a toxin that builds up over time. Instead of through inhalation, ethanol poisoning typically occurs from the consumption of liquid ethanol in alcoholic beverages. This distinction determines the two primary areas of application necessary for ethanol determination: measuring the concentration levels in all sorts of alcoholic beverages and evaluating the blood ethanol levels in people after consuming alcoholic beverages.
Given that ethanol is a renewable feedstock and has a high hydrogen concentration, ethanol reforming is thought to be a very intriguing technology for producing hydrogen. Potentially significant hydrogen yields could be attained with ethanol reforming with full ethanol conversion at relatively low temperatures. However, at low temperatures, the hydrogen yield is reduced since methane is the principal byproduct of ethanol's breakdown. Larger temperatures, which have worse energy efficiency, or a more intelligent reactor and process design are needed to produce higher hydrogen contents.
What is Methanol?
Now, the simplest alcohol is methanol, which has the chemical formula CH3OH and is also known as methyl alcohol and other names (a methyl group linked to a hydroxyl group, often abbreviated MeOH). It has a pronounced alcoholic odor resembling that of ethanol and is a colorless, light, volatile liquid that is combustible (potable alcohol). Methanol is a polar solvent that was originally primarily created by the destructive distillation of wood, hence the term "wood alcohol." Nowadays, industrial production of methanol primarily involves hydrogenating carbon monoxide.
A methyl group and a polar hydroxyl group are joined to form methanol. It is manufactured more than 20 million tons annually and serves as a precursor to a variety of more specialized chemicals as well as formaldehyde, acetic acid, methyl tert-butyl ether, methyl benzoate, anisole, and other common chemicals.
Normal, healthy human beings contain trace levels of methanol. In one investigation, the mean amount of 4.5 ppm was discovered in test individuals' exhaled air. Fruit pectin, which can yield up to 1.4 g of methanol per kilogram of apple, can be used to metabolize the average amount of endogenous methanol that humans create each day or 0.45 g.
Phytoplankton and anaerobic bacteria both make methanol. Astronomy uses methanol as a marker for star-forming regions since it is present there in large numbers. Its spectrum emission lines enable detection. A huge cloud of methanol measuring 463 terameters (288 billion miles) broad in the universe was found in 2006 by astronomers using the MERLIN array of radio telescopes at Jodrell Bank Observatory.
Strongly flammable is methanol. Its vapors can move and ignite, and they are slightly heavier than air. Dry chemicals, carbon dioxide, water spray, or alcohol-resistant foam should be used to put out methanol fires.
Now, pure methanol, in concentrations as low as 10 mL (0.34 US fl oz), can permanently impair vision by damaging the optic nerve. One US fl oz (30 mL) could be lethal. The average lethal dose of pure methanol is 100 mL (3.4 US fl oz), or 1-2 mL/kg body weight. Methanol is administered at a reference dose of 0.5 mg/kg per day. Hours after consumption, toxic consequences start to manifest, however, antidotes can frequently avert irreparable harm.
It is difficult to distinguish between it and ethanol (the alcohol found in beverages) due to their similarity in color and odor. And this is true of denatured alcohol, adulterated liquors, and particularly low-quality alcoholic beverages. There are two ways that methanol is harmful. First, for its effects on the central nervous system, which works as a central nervous system sedative in a similar way to ethanol poisoning, methanol can be lethal. The liver's alcohol dehydrogenase enzyme begins the toxication process by converting it to formic acid, which is visible as the formate ion, via formaldehyde. Alcohol dehydrogenase (ADH) changes methanol into formaldehyde, and aldehyde dehydrogenase converts formaldehyde into formic acid (formate).
Inhibiting mitochondrial cytochrome c oxidase results in hypoxia at the cellular level, metabolic acidosis, and several other metabolic abnormalities, making formate poisonous.
Methanol poisoning outbreaks have mostly been brought on by contaminated alcohol consumption. The developing world is where this is more typical. Despite this, there were over 1700 cases in the US in 2013. Adult guys are frequently the ones afflicted. Early therapy may lead to favorable outcomes. Methanol toxicity was first documented in 1856.
The foundation of many gases to liquids technologies is the condensation of methanol to create hydrocarbons and even aromatic systems. These include the conversions of methanol to hydrocarbons (MtH), gasoline (MtG), olefins (MTO), and propylene (MTP) (MTP). Zeolites function as heterogeneous catalysts to catalyze these reactions. The MtG procedure was briefly made available for purchase in Motunui, New Zealand.
According to the European Fuel Quality Directive, methanol up to 3% and an equal amount of cosolvent may be added to gasoline marketed in Europe. China employs methanol as a transportation fuel in low-level blends for ordinary vehicles and high-level blends for vehicles made for methanol fuels, totaling more than 4.5 billion gallons annually. However, in recent years, the majority of gasoline-powered cars and trucks can now use a range of alcohol fuels, producing equivalent or higher horsepower, with just a little update to the car's software settings and perhaps a $50 seal or tube component.
Main Differences Between Ethanol and Methanol In Points
- Methanol or methyl alcohol cannot be taken since it is toxic, whilst ethanol, or ethyl alcohol, is a basic form of alcohol that is used to produce alcoholic beverages and may be ingested.
- In opposition to methanol, that has a yellow flwhichonce lit on fire, ethanol burns with a blue flame.
- Methanol is also known as methyl alcohol, whereas ethanol is commonly known as "grain alcohol" or ethyl alcohol.
- Methanol is more acidic than water, although ethanol is a fairly poor acid when compared to water.
- When ethanol is heated with iodine in the presence of NaOH for the iodoform test, it generates a yellow-colored precipitate, whereas methanol does not respond favorably to the same treatment.
Conclusion
Hence, now we got to know the differences between ethanol and methanol in detail.
References
- ethanol. (n.d.). Retrieved from Britannica: https://www.britannica.com/science/ethanol
- Ethanol. (n.d.). Retrieved from ScienceDirect: https://www.sciencedirect.com/topics/chemical-engineering/ethanol
- Methanol. (n.d.). Retrieved from WIKIPEDIA: https://en.wikipedia.org/wiki/Methanol
