In alcohol: Physical properties of alcohols is referred to as a hydrophilic (“water-loving”) group, because it forms hydrogen bonds with water and enhances the solubility of an alcohol in water. Methanol, ethanol, n -propyl alcohol, isopropyl alcohol, and t -butyl alcohol are all miscible with water. Alcohols with higher molecular weights tend to be less water-soluble, because the
Is ethanol hydrophobic or hydrophilic?
Ethanol is an interesting molecule. It is polar or hydrophilic (water-loving) due to the presence of the terminal hydroxyl group, so it dissolves in water.
Why are alcohols hydrophobic?
Due to the presence of non-polar groups in alcohol, interactions of the amino acids in proteins are different in water and in alcohol. In fact, water-ethanol mixtures have been used to establish the hydrophobicity of amino acids.
Does alcohol have both hydrophilic and hydrophobic side?
Alcohols are also the simplest form of amphiphilic molecules having both hydrophobic and hydrophilic segments.
Is ethanol hydrophilic or lipophilic?
INTRODUCTION – It is well known that even small changes in the composition of cell membranes can strongly affect the functioning of intrinsic membrane proteins, such as ion and water channels, which regulate the chemical and physical balance in cells ( 1, 2 ).
Such changes may occur due to the introduction of short-chain alcohols, or other anesthetics, at membrane surfaces. Although anesthetics are being used every single day in hospitals around the world, the molecular level mechanisms of general anesthesia remain elusive (see e.g., ( 3 – 5 )). The same applies to the effect of alcohols on biological systems.
Klemm ( 6 ) provides a good review of the topic. Another aspect to the effect of alcohols appears in a more applied context. In the process of producing alcoholic beverages, wine in particular, yeasts like Saccharomyces cerevisiae have to sustain high ethanol concentrations without losing their viability.
- However, in ∼10% of all wine fermentations, the industry encounters so-called stuck fermentations ( 7, 8 ).
- There is no satisfactory understanding of this effect.
- Some models propose that an effect very similar to general anesthesia is responsible for rendering the yeast cells dormant ( 9 ).
- It has been suggested that high alcohol concentrations change the membrane structure and force transmembrane proteins into unfavorable conformations.
In these conformations, proteins cannot fulfill their functions and thus the yield drops dramatically. In addition to the above aspects, there are also other important issues. In particular, in cellular systems such as bacteria and yeast, the toxicity of ethanol has been suggested to be due to its interaction with membranes ( 8, 10, 11 ) and the consequent general effects such as changes in the mechanical properties of permeability and diffusion.
- Changes in such generic membrane properties may affect the functions of proteins and binding sites due to changes in lateral pressure ( 4 ), or, if the membrane becomes more permeable, changes in the electrostatic potential may affect signaling.
- These effects are not to be mixed up with the toxicity due to metabolic products such as acetaldehyde from consumption of ethanol—the cause of poisoning commonly known as hangover.
We concentrate on the effects of ethanol and methanol on structural properties of membranes. It is quite surprising that despite a vast number of clinical and biochemical studies, there have been very few computational investigations of the effect of short-chain alcohols, or other anesthetics, on membranes.
- The only simulational studies of bilayers and ethanol are, to the authors’ knowledge, the one by Feller et al.
- 12 ), who used molecular dynamics simulations of ethanol and palmitoyloleoylphosphatidylcholine (POPC) lipid bilayers and NMR to study the molecular level interactions in these systems, and the article by Lee et al.
( 13 ) discussing alcohol-membrane systems briefly. Direct comparison of all of our results with Feller et al. ( 12 ) is not meaningful since their study was performed using a different ensemble, alcohol concentration, and with different hydration. For methanol-bilayer systems there exists, to the authors’ knowledge, only one computational article ( 14 ).
- For anesthetics, the situation is slightly better.
- Tang and Xu ( 5 ) used molecular dynamics simulations to study molecular level mechanisms of general anesthesia using halothane as a specific anesthetic.
- They concluded that the global effects of anesthetics, i.e., due to generic interaction mechanisms, are important and lead to modulations in the functions of channels and/or proteins.
These conclusions are also supported by the fact that the same anesthetics are effective for humans and a variety of animals. Similar conclusions for halothane interactions with bilayers have been pointed out by Koubi et al. ( 15, 16 ). The importance of generic effects has also been indicated in recent experimental studies of the effect of ethanol on Oenococcus oeni cells ( 8 ).
Although the shortage of simulational studies may be due to the high computational demands of these systems, it is still surprising since computer simulations can provide detailed information about fundamental molecular level mechanisms. In this article, we study the effect of two short-chain alcohols, ethanol and methanol, on two different lipid membranes consisting of either pure dipalmitoylphosphatidylcholine (DPPC) or POPC.
Methanol is a small solute having a single hydrophilic hydroxyl group whereas ethanol possesses an additional hydrophobic carboxyl group. DPPC and POPC share the same headgroup but one of the chains of POPC has a double bond and is two carbon-atoms longer, whereas DPPC has only single bonds in its chains (see Fig.1 ). Structures of POPC ( top ) and DPPC ( bottom ). They are identical with the exception of the sn −2 chain, which is two carbons longer and contains one double bond for POPC. Phospholipid bilayers can be considered as a first approximation to understand the behavior of cell membranes under the influence of alcohol, and much information can be extracted from such systems.
Our simulations show that ethanol is able to pass through the bilayer much more easily than methanol. This can be explained by the hydrophobic nature of the carbon tail of ethanol, making passing through the hydrophobic chain regions of lipid bilayers easier. In addition, ethanol molecules condense near the interface region between lipids and the surrounding water, i.e., there is a sharply increased density of ethanol near the interface region, whereas for methanol, only a moderate increase of the density is seen near the region of the interface.
These effects are very pronounced for DPPC bilayers, and only slightly weaker for POPC bilayers. This has far reaching implications for the basic properties of bilayers. The rest of this article is organized as follows. In the next section, we describe the model and the simulation details.
Is alcohol A hydrophilic?
In alcohol: Physical properties of alcohols is referred to as a hydrophilic (“water-loving”) group, because it forms hydrogen bonds with water and enhances the solubility of an alcohol in water. Methanol, ethanol, n -propyl alcohol, isopropyl alcohol, and t -butyl alcohol are all miscible with water. Alcohols with higher molecular weights tend to be less water-soluble, because the
Is ethanol a hydrophobic solvent?
Solvent – Ethanol is considered a universal solvent, as its molecular structure allows for the dissolving of both polar, hydrophilic and nonpolar, hydrophobic compounds. As ethanol also has a low boiling point, it is easy to remove from a solution that has been used to dissolve other compounds, making it a popular extracting agent for botanical oils.
Cannabis oil extraction methods often use ethanol as an extraction solvent, and also as a post-processing solvent to remove oils, waxes, and chlorophyll from solution in a process known as winterization, Ethanol is found in paints, tinctures, markers, and personal care products such as mouthwashes, perfumes and deodorants.
Polysaccharides precipitate from aqueous solution in the presence of alcohol, and ethanol precipitation is used for this reason in the purification of DNA and RNA,
Why is alcohol nonpolar?
Hint: A compound is said to be polar when they develop charges on them when they are separated. The concept of polarity is attributed to the difference in the electronegativity between the two atoms. R-OH is basic alcohol, where R is the alkyl group and OH is the hydroxyl group.
- Complete Step By Step Answer: Alcohols can be a solvent and they are said to be polar if they develop positive and negative charges when the bond between the alkyl group (R) and Hydroxyl group is broken.
- The Oxygen atom is bonded to the carbon atom in alcohol.
- The polarity of alcohol depends on the electronegativity difference between carbon and oxygen.
Mostly a solvent dissolves a cation easily as compared to an anion. It is very important to know that hydroxyl is responsible for making the alcohol polar. This is because they form hydrogen bonds with other atoms and thus dissolve in a solvent. We know that like dissolves like.
- Alcohols are polar so they readily dissolve in polar solvents like water.
- As R-OH consists of the OH group we can say that it is half a water molecule.
- So lower alcohols are miscible with water.
- However, the alkyl part of the alcohol is hydrophobic and thus makes the hydrocarbyl tail grow longer.
- This is the reason the polarity and solubility of alcohol decreases.
Note: In alcohol the –OH side of the molecule is the polar end and the methyl side of the molecule is the nonpolar end. Oxygen is more electronegative than carbon so it attracts more electrons towards itself. Oxygen gains a negative charge and carbon gains a positive charge.
Are alcohols always soluble in water?
Video Transcript – The following table describes the chemical formula of five alcohols. Which of these alcohols should be the least soluble in water? Alcohols are organic molecules that contain at least one hydroxy group. This question presents five alcohol molecules that each contain a single hydroxy group.
We need to identify the molecule that should be the least soluble in water. Substances tend to be soluble in one another if both substances exhibit similar intermolecular forces. Water molecules are polar due to the large electronegativity difference between the oxygen and hydrogen atoms. The partial positively charged hydrogen atom of one water molecule experiences a strong electrostatic attraction to the lone pair electrons of an oxygen atom from another water molecule.
This strong electrostatic attraction is called hydrogen bonding. Similar to water, the hydroxy group of an alcohol is polar due to the large electronegativity difference between the oxygen and hydrogen atoms. As such, small alcohol molecules, such as methanol, exhibit strong hydrogen bonds with one another.
As methanol and water molecules exhibit similar intermolecular forces, they can form strong hydrogen bonds with one another and the two substances are soluble in each other. All alcohol molecules contain polar hydroxy groups. But not all alcohol molecules are as soluble in water as methanol, and some alcohols are considered insoluble in water.
Let’s consider the alcohol pentan-1-ol. The hydroxy group is polar and could exhibit hydrogen bonding with water molecules. But the long hydrocarbon chain is nonpolar and cannot hydrogen bond. Because the long hydrocarbon chain cannot form hydrogen bonds with water, it is less energetically favorable for the alcohol to dissolve.
- So pentan-1-ol is less soluble in water than methanol.
- In general, the solubility of an alcohol in water tends to decrease as the length of the carbon chain increases.
- So the alcohol that should be the least soluble in water is the alcohol that has the longest carbon chain.
- Of the answer choices, the alcohol with the longest carbon chain is pentan-1-ol.
So the alcohol that should be the least soluble in water is pentan-1-ol.
Are fatty alcohols hydrophobic?
Home > Knowledge center > Ethoxylated Fatty Alcohols: mild for fabric, skin and wallet Fatty alcohols are hydrophobic; water repellent. To make a surfactant molecule out of fatty alcohols one side should hold a hydrophilic group. Like this, dirt can dissolve in the fatty part, while the hydrophilic group maintains contact with the water; the principle of washing. “Mild on clothes, skin and wallets” Contrary to negatively charged cleaners (anionic surfactants) and positively charged cleaners (cationics), ethoxylated fatty alcohols have no charge. By ethoxylating fatty alcohols (adding an ethoxy group –O-C2H5) an accessible oxygen atom comes available.
- The oxygen atom forms so called hydrogen bridges with the water molecules.
- This way, without a charge, still a hydrophilic end is added to the fatty alcohol molecule.
- They remain non-ionic, and therefore less aggressive in their cleaning.
- This explains their mild behaviour.
- An ethoxylated fatty alcohol is characterised by the length of its fat-alcohol chain and by how many ethoxy groups are attached to that chain.
The length of the (dirt dissolving) fatty chain is indicated by the number of C-atoms (“C12-C18” means chains of 12 to 18 C-atoms). The number of (water binding) ethoxy groups is depicted by the amount of “mol EO”, a measure for the number of molecules Ethylene Oxide.
Our ethoxylated fatty alcohols are ideal for use in liquid detergents. As they are non-ionics, having no charge, these raw materials result in mild cleaners, such as wool detergents. The mildest types are those with a linear C-chain (no branches). These are also optimally broken down biologically. Just like we, bacteria rather not place their teeth in products with complex 3-dimensional structures.
A “bar” of C-chains is easier consumed. The features of linear ethoxylated fatty alcohols are:
Mild cleaners (wool, face, hands) Emulsifying (avoid sagging of other ingredients, such as fragrances and colourants in the end product) Dissolving (hydrophobic ingredients are kept in solution by ethoxylated fatty alcohols in a water based end product) Wetting of surfaces (so the cleaning job by the end product becomes more effective, or by enhancing the moisturizing job of skin and hair –conditioner-cosmetics)
Ethoxylated fatty alcohols are stable up to 130oC and within a broad pH range. The Sirius Effect Sirius International has long searched for competitive ethoxylated fatty alcohols. The one manufacturer produces its own fat-alcohols, but has to buy the Ethylene Oxide, or source out the ethoxylation.
C12-14 1mol, 2mol, 3mol, 5mol, 7mol, 9mol EO C12-18 7mol EO
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Which part of the alcohol is hydrophobic?
Most of the common alcohols are colourless liquids at room temperature. Methyl alcohol, ethyl alcohol, and isopropyl alcohol are free-flowing liquids with fruity odours. The higher alcohols—those containing 4 to 10 carbon atoms—are somewhat viscous, or oily, and they have heavier fruity odours.
|*Ph represents the phenyl group, C 6 H 5 —.
|CH 3 OH
|CH 3 CH 2 OH
|CH 3 CH 2 CH 2 OH
|(CH 3 ) 2 CHOH
|CH 3 (CH 2 ) 3 OH
|(CH 3 )CH(OH)CH 2 CH 3
|(CH 3 ) 2 CHCH 2 OH
|(CH 3 ) 3 COH
|CH 3 (CH 2 ) 4 OH
|(CH 3 ) 2 CHCH 2 CH 2 OH
|(CH 3 ) 3 CCH 2 OH
|cyclo-C 5 H 9 OH
|CH 3 (CH 2 ) 5 OH
|cyclo-C 6 H 11 OH
|CH 3 (CH 2 ) 6 OH
|CH 3 (CH 2 ) 7 OH
|CH 3 (CH 2 ) 8 OH
|CH 3 (CH 2 ) 9 OH
|H 2 C=CH−CH 2 OH
|Ph−CH 2 OH*
|Ph 2 CHOH*
|Ph 3 COH*
|density (grams per millilitre)
|solubility in water
The boiling points of alcohols are much higher than those of alkanes with similar molecular weights. For example, ethanol, with a molecular weight (MW) of 46, has a boiling point of 78 °C (173 °F), whereas propane (MW 44) has a boiling point of −42 °C (−44 °F). The oxygen atom of the strongly polarized O―H bond of an alcohol pulls electron density away from the hydrogen atom. This polarized hydrogen, which bears a partial positive charge, can form a hydrogen bond with a pair of nonbonding electrons on another oxygen atom.
- Hydrogen bonds, with a strength of about 5 kilocalories (21 kilojoules) per mole, are much weaker than normal covalent bonds, with bond energies of about 70 to 110 kilocalories per mole.
- The amount of energy per mole that is required to break a given bond is called its bond energy.) Water and alcohols have similar properties because water molecules contain hydroxyl groups that can form hydrogen bonds with other water molecules and with alcohol molecules, and likewise alcohol molecules can form hydrogen bonds with other alcohol molecules as well as with water.
Because alcohols form hydrogen bonds with water, they tend to be relatively soluble in water. The hydroxyl group is referred to as a hydrophilic (“water-loving”) group, because it forms hydrogen bonds with water and enhances the solubility of an alcohol in water.
Methanol, ethanol, n -propyl alcohol, isopropyl alcohol, and t – butyl alcohol are all miscible with water. Alcohols with higher molecular weights tend to be less water-soluble, because the hydrocarbon part of the molecule, which is hydrophobic (“water-hating”), is larger with increased molecular weight.
Because they are strongly polar, alcohols are better solvents than hydrocarbons for ionic compounds and other polar substances.
Is alcohol hydroscopic?
Specifically – To be more specific, let’s consider how this variation in ethanol content affects the two critical parameters of the fuel (Stoichiometric Air Fuel Ratio and Octane Rating) using the extremes of 83% ethanol, and 51% ethanol.1. Stoichiometric Air Fuel Ratio – Pure ethanol has a stoichiometric air fuel ratio of 9.003.
- The stoichiometric air fuel ratio of gasoline ranges from approximately 14.5 to 15.0 but is generally considered to be 14.7.
- Accordingly, the stoichiometric air fuel ratio of a mix of 85% ethanol and 15% gasoline is 9.972:1, while the ratio for a mix of 51% ethanol, 49% gasoline is 12.15:1.
- Based on these numbers, if we tuned our engine to a lambda value of,85 in the middle of winter, we could expect a lambda value of 1.036 when we switch to our summer mix.
Seem extreme? It is! I did say specific, so let’s include the density of the two fuels to make our numbers more accurate. Performing the same calculation, but accounting for ethanols high specific gravity of,79, and using a value of,72 for gasoline, we get a summer mix lambda of 1.006.
- Not quite as extreme, but still off in left field, and likely to rattle itself to death, or turn a piston into swiss cheese.
- Fortunately the summer mix will have better detonation resistance, and better cylinder cooling due to its higher ethanol content, but if the tune was anywhere near optimized before, it sure isn’t now.2.
Octane – There are two considerations here. The first and most obvious is that as the ethanol content is decreased, the octane rating, or detonation resistance of the fuel, will also be decreased. The second, and not so obvious, is based on the ridiculously vague definition of what hydrocarbons may be used to “tune” the volatility of the blend.
- In case you forgot I will post it here again;
- “Unleaded gasoline, gasoline blendstocks for oxygenate blending (BOB), natural gasoline, or other hydrocarbons in the gasoline boiling range.”
- Since the overall octane rating or detonation resistance of the blend is dependent on all the components that make up the fuel, we have no way to estimate the octane rating of the final blend even if the ethanol content remains constant.
Why is alcohol soluble in water?
Answer: The following elements have an impact on how soluble alcohols are in water: (i) Hydrogen bonding – Alcohols are relatively soluble in water and create hydrogen bonds with it. Alcohol is soluble because its hydroxyl group is hydrophilic, or “water-loving,” and forms hydrogen bonds with water.
Is alcohol A lipophilic?
Where Does Alcohol Go in the Body? – The Alcohol Pharmacology Education Partnership As ethanol circulates throughout the bloodstream, the concentration gradient is in the direction that favors movement of ethanol from the capillaries through interstitial spaces and into cells of different organs.
- The loosely packed endothelial cells and the fenestrae allow ethanol to move easily out of the capillaries.
- There is an exception to the “leaky” capillaries—and that’s in the brain.
- There, the capillaries do not have fenestrae and the endothelial cells are tightly packed together.
- This construction helps to form a barrier (the “blood-brain-barrier”) to drugs and other molecules that are charged or polar, preventing them from entering the brain itself.
Because alcohol is slightly lipophilic, it can still diffuse across the brain endothelial cell membrane, with the concentration gradient to get into (or out of) the brain. In the brain, alcohol interferes with brain cell function to cause intoxication (and a host of other things!). Figure 1.8 Capillaries in the brain are an exception; the endothelial cells are tightly packed and do not contain fenestrae or holes. Because ethanol is slightly lipophilic, it can still diffuse through the lipid bilayer of these endothelial cells. about the blood-brain-barrier.
Are lipids soluble in alcohol?
Fats are not dissolved in water due to their nature, which is non-polar (hydrophobic), but it is soluble in organic solvents such as chloroform, benzene, and boiling alcohol. Different lipids have ability to dissolve in different organic solvent.
Is lipophilic always hydrophobic?
Is alcohol as polar as water?
Polarity Affects the Boiling Point Since alcohol is less polar than water, alcohol evaporates faster than water and boils at a lower temperature.
Are alcohols always nonpolar?
Alcohols are organic compounds which contain a hydroxyl (—OH) group covalently bonded to a carbon atom. Alcohols take part in a wide variety of chemical reactions, and are also frequently used as solvents. The word “alcohol” comes from the Arabic term al kohl meaning “the fine powder.” Originally, this referred to an antimony sulfide compound (Sb 2 S 3 ) used for eye shadow and as an antiseptic, which was ground up to form a fine powder, but then later came to refer to any finely divided powder.
In the Middle Ages, this term came to mean the “essence” of anything. When the Europeans took up alchemy in the Middle Ages, they referred to vapors from evaporating or boiling compounds as “spirits,” since they did not believe them to be material in the same sense that solids and liquids were. Alchemists began referring to “spirits of wine,” and since an alcohol when it boils away seems to powder away to nothing, they also began to refer to “alcohol of wine” and then simply “alcohol”.( 1 ) Simple alcohols are often referred to by common names derived by adding the word “alcohol” to the name of the appropriate alkyl group.
For instance, a chain consisting of one carbon (a methyl group, CH 3 ) with an OH group attached to the carbon is called “methyl alcohol” while a chain of two carbons (an ethyl group, CH 2 CH 3 ) with an OH group connected to the CH 2 is called “ethyl alcohol.” For more complex alcohols, the IUPAC nomenclature must be used.
- Straight-chain and branched alcohols are named by first selecting the longest continuous chain of carbon atoms containing the carbon to which the OH group is bonded.
- The longest chain is named as an alkane, and the final -e is changed to an -ol,
- A locator number is placed immediately in front of the prefix to indicate the location of the alcohol group.
Thus, the name “1-propanol” indicates a three carbon chain with an OH group on carbon number 1, and the name “2-propanol” indicates a three-carbon chain with an OH group on carbon number 2. Cyclic alcohols, in which the OH group is attached to a carbon atom in a ring, are named in a similar fashion.
The ring is taken to be the longest chain, and the carbon bearing the OH group is numbered as carbon number 1. Unless there is more than one OH group on the ring, the number “1” is usually omitted from the name, since it is understood that the OH group is on carbon 1. The oxygen atoms in alcohols are sp 3 -hybridized, and have bent shapes, with bond angles of slightly less than 109.5 to each other.
Alcohols are polar, since they have oxygen-hydrogen bonds, which allow alcohol molecules to attract each other through hydrogen bonds, Since oxygen atoms are much more electronegative than hydrogen atoms, the oxygen-hydrogen bond is especially polar.
The partially-negatively charged oxygen atom on one alcohol molecule is strongly attracted to the partially positively charged hydrogen atom on another alcohol molecule; this strong attraction results in much stronger intermolecular forces between alcohol molecules than there are between nonpolar alkanes of the same molar mass.
Alcohols are generally more soluble in water than alcohols of the same molecular mass; low-molecular weight alcohols such as methanol and ethanol are miscible with water, and solubility decreases as the number of carbons in the alcohol increases. Alcohols also have much higher boiling points than alkanes of the same molecular weight: for example, propane (molecular mass 42.08 g/mol) has a boiling point of -44.5 C, while ethanol (MM 46.07 g/mol) has a boiling point of 78.3 C,
|Methanol, also known as methyl alcohol and wood alcohol, is the simplest of the alcohols. The name is derived from the Greek words “methy” (wine) and “hule” (wood). Methanol is is found in wood smoke, and contributes to the odor of wine. It is metabolized in the body to produce formaldehyde and formic acid, and is toxic if more than 50 mL is consumed; smaller amounts can cause blindness. Industrially, methanol is produced from synthesis gas, a mixture of carbon monoxide and hydrogen derived from coke (the coal, not the soda) or methane. Methanol is used as the fuel in some racing cars, and is being investigated as an renewable alternative to the use of petroleum-based fuels. The main use of methanol, however, is in the manufacture of other chemicals, such as formaldehyde, which is used in the manufacture of plastics, paints, plywood, etc.
|Ethanol, also known as ethyl alcohol and grain alcohol, is the alcohol found in alcoholic beverages. The fermentation of the sugars found in honey, grain, or fruit juices by yeasts to yield beers and wines was probably the first chemical reaction to be discovered. Ethanol can be purified and concentrated by fractional distillation, but ethanol and water form an constant-boiling azeotrope at a concentration of 95% ethanol and 5% water which cannot be separated by distillation; absolute ethanol, which contains no water, is produced by fractional distillation of 95% ethanol with small amounts of benzene. Ethanol that is intended for industrial use is “denatured” (rendered unfit for human consumption) by adding small amounts of methanol, denatonium benzoate, or other unpleasant or toxic substances, which exempts the alcohol from liquor taxes. Ethanol is metabolized in the body, primarily by the enzyme alcohol dehydrogenase, to produce acetaldehyde; the buildup of acetaldehyde in the blood is one of the factors which contributes to the symptoms of a hangover. Physiologically, ethanol acts as a depressant, but since it frees parts of the cortex from inhibitory controls, to its consumer, it seems to be a stimulant. Ethanol is a primary (1 ) alcohol, and is easily oxidized by mild oxidizing agents, such as chromic acid (H 2 CrO 4 ) or potassium dichromate (K 2 Cr 2 O 7 ), in which the chromium is in the +6 oxidation state. These substances undergo a distinct color change on reaction with ethanol: in the +6 oxidation state chromium compounds are typically a dark reddish-orange color; after the alcohol is oxidized, the chromium is reduced to the +3 oxidation state, which is green. The color change from red-orange to green forms the basis of some of the simple breathalyzer tests that are used to test motorists who are suspected of driving while drunk. Ethanol can also be oxidized in air, forming acetic acid, the active ingredient in vinegar. Alcoholic beverages that are not stored properly can end up tasting like vinegar because of the formation of acetic acid (see entry for acetic acid).
|1-Propanol (Propyl alcohol)
|1-Propanol, or propyl alcohol, is a three-carbon alcohol with the OH group on an end carbon. Its structural isomer, 2-propanol, is described below.
|2-Propanol (Isopropyl alcohol)
|2-Propanol, or isopropyl alcohol, is a three-carbon alcohol with the OH group on the middle carbon. Isopropyl alcohol is a secondary alcohol, Rubbing alcohol is a solution of 70% isopropyl alcohol and 30% water, which is commonly used in sterilizing swabs and disinfectants. Isopropyl alcohol is a secondary (2 ) alcohol, and is easily oxidized by mild oxidizing agents.
|1-Butanol (Butyl alcohol)
|1-Butanol, or butyl alcohol, is a four-carbon chain, with the OH group on an end carbon. It is used as a solvent and a paint thinner, and has some potential use as a biofuel. Butyl alcohol is a primary (1 ) alcohol, and is easily oxidized. There are three other structural isomers of 1-butanol: 2-butanol ( sec -butyl alcohol), 2-methyl-1-propanol (isobutyl alcohol), and 2-methyl-2-propanol ( tert -butyl alcohol).
|2-Butanol ( sec -Butyl alcohol)
|2-Butanol, or sec -butanol, or sec -butyl alcohol, or s -butyl alcohol, is a four-carbon chain, with the OH group on the second carbon. (Since the alcoholic carbon is connected to two other carbons, it is secondary, hence the prefix “sec”.) It is used as a solvent and an intermediate in the manufacture of other compounds. sec -Butyl alcohol is a secondary (2 ) alcohol, and is easily oxidized.2-Butanol is a chiral compound, and exists in two enantiomeric forms: (R)-2-butanol and (S)-2-butanol:
|The 3D structure shown above is the R stereoisomer.
|2-Methyl-1-propanol (Isobutyl alcohol)
|2-Methyl-1-propanol, or isobutanol, or isobutyl alcohol, is a three-carbon chain, with the OH group on and end carbon and a methyl group on the middle carbon. It is used as a solvent, in paints and inks, and in the manufacture of some coatings and varnishes. Isobutyl alcohol is a primary (1 ) alcohol, and is easily oxidized.
|2-Methyl-2-propanol ( tert -Butyl alcohol)
|2-Methyl-2-propanol, or tert -butanol, or tert -butyl alcohol, or t -butyl alcohol, is a three-carbon chain, with the OH group and a methyl group on the middle carbon. (Since the alcoholic carbon is connected to three other carbons, it is tertiary, hence the prefix “tert”.) It is used as a solvent, a denaturant for ethanol, as an octane booster in gasoline, and in some pain thinners. tert -Butyl alcohol is a tertiary (3 ) alcohol, and does not react with oxidizing agents. It is useful in organic synthesis, in the form of the t -butoxide anion, which is generated by the reaction of tert -butanol with sodium or a strong base such as sodium hydride, which removes the slightly acidic hydrogen from the OH group, leaving behind a negative charge on the oxygen. The t -butoxide anion is a strong base, but its steric bulk makes it slow to participate in nucleophilic substitution reactions, making it more likely to participate in elimination reactions.
|Ethylene glycol (1,2-Ethanediol)
|1,2-Ethanediol, better known as ethylene glycol, is an alcohol which contains two OH groups. Molecules which contain two OH groups on adjacent carbons are often known as glycols, It is a viscous, colorless, odorles liquid, with a sweet taste. It is miscible with water, since there are two locations on the molecule which can form hydrogen bonds with water. It has an extremely high boiling point for such a small molecule, 197 C; this is because these molecules can form more than one set of hydrogen bonds to each other. Ethylene glycol is produced industrially from ethylene: the ethylene is oxidized to form ethylene oxide, which reacts with water to produce ethylene glycol. It is used in the manufacture of they polyester polyethylene terephthalane (PET), and also to remove water vapor from natural gas. Ethylene glycol is used in antifreeze — pure ethylene glycol freezes at -12.9C (8.8F), but a 50:50 mixture of ethylene glycol and water freezes at around -40C (-40F). It is also used as an airplane de-icer, a humectant (an anti-drying agent that keeps other substances moist), used in ball point pen inks. Ethylene glycol is toxic; in the body it is metabolized into glycolic acid (if one alcohol group is oxidized to a carboxylic acid) and oxalic acid (if both alcohol groups are oxidized), which can cause irregular heartbeat and respiration, and kidney failure. The antidote for ethylene glycol poisoning is ethanol: since ethanol competes for the same alcohol dehydrogenase enzyme that metabolizes ethylene glycol, flooding the body with alcohol can help to flush the ethylene glycol out of the system.
|Propylene glycol (1,2-Propanediol)
|1,2-Propanediol, or propylene glycol, is a tasteless, odorless, clear liquid. Like ethylene glycol, it is miscible with water, because of hydrogen bonding. It is used in antifreeze, as a moisturizer in lotions, foods, and some medicines and cosmetics, and as a solvent for food dyes. It is also used to make artificial smoke.
|Glycerol / Glycerin (1,2,3-Propanetriol)
|1,2,3-Propanetriol, better known as glycerol or glycerin, is a viscous, colorless, odorless, sweet-tasting liquid. It is used as an emollient (softening agent) in cosmetics; as a humectant (anti-drying agent) in toothpaste, candies, medicines, tobacco (where it keeps leaves from drying and crumbling), and glues (prevent glue from drying in the bottle). It is also used in some plastics, especially cellophane, as a plasticizer to keep the plastic soft and pliable. Glycerol also contributes to the sweet, smooth taste of some wines. Because it can form three sets of hydrogen bonds, it is extremely soluble in water, and has a very high boiling point (290C). Glycerol combines with fatty acids (long-chain carboxylic acids) to make an series of biologically important molecules called the triglycerides (fats and oils).
|Benzyl alcohol, or phenylmethanol, is used in perfumes, flavors, soaps, cosmetics, ointments, and ball point pen inks; it is also used in some anti-itching medications.
|Cinnamic alcohol, or cinnamyl alcohol, is found in cinnamon leaves (hence the name), usually in the form of an ester; it is also found in Tolu balsam, the resin of the Myroxylon toluifera tree. It has an odor similar to that of hyacinth, and is used in perfumes (particularly in lilac and other floral scents), deodorants, flavoring agent, soaps, and cosmetics.
|Diethylene glycol (DEG) is a colorless, odorless, toxic liquid used as an industrial solvent, and in the synthesis of other organic molecules. It is also used as a humectant for tobacco, and some inks and glues. In 1937, the S.E. Massengill Co. marketed sulfanilamide (a sulfa drug) dissolved in diethylene glycol as “Elixir Sulfanilamide”; over a hundred people died of poisoning by the DEG, and this incident catalyzed the passage of the 1938 Federal Food, Drug, and Cosmetic Act, which greatly expanded the power of the Food and Drug Administration (FDA) to regulate the safety of foods, medicines, and cosmetics. Several other cases of DEG poisoning have resulted from DEG either being added to wines in an attempt to sweeten them, or because of its presence in improperly purified medications and cosmetics. In May of 2007, several cheap brands of toothpaste originating in China were removed from the market in several countries because they were found to be contaminated with DEG (labeled on the containers as “glycerine”).
|Grandisol, or (+)-(1 R,2 S )-1-(2′-hydroxyethyl)-1-methyl-2-isopropenylcyclobutane, is a pheromone which acts as the sex attractant of the cotton boll weevil ( Anthonomus grandis ) and some related insects. It is used in a insecticide called grandlure, which attracts and traps or kills these damaging insects.
|Cyclohexanol is a cyclic, secondary alcohol. It is used in some organic synthesis reactions, in the manufacture of celluloid, textiles, and some insecticides.
1 ) Isaac Asimov, “You, Too, Can Speak Gaelic” in Asimov on Chemistry, Garden City: Anchor Books, 1975, p.127.P.W. Atkins, Molecules, 2nd ed. Cambridge: Cambridge University Press, 2003, p.48-52, 58-59. Richard J. Lewis, Sr., Hawley’s Condensed Chemical Dictionary, 13th ed.
What liquids are hydrophilic?
Liquid chemicals – Examples of hydrophilic liquids include ammonia, alcohols, some amides such as urea and some carboxylic acids such as acetic acid.
Is water soluble in ethanol?
Ethanol has an overall polarity that allows it to make hydrogen bonds to water easily, allowing solubility.
Is ethanol alcohol polar or nonpolar?
Answer and Explanation: – Ethanol is a polar molecule. Ethanol’s chemical formula is CH 3 CH 2 OH. The electronegativity difference between carbon (2.55) and hydrogen (2.20) is. See full answer below.
Is ethanol water polar or nonpolar?
Ethanol is a very polar molecule due to its hydroxyl (OH) group, which forms hydrogen bonds with other molecules. The ethyl (C 2 H 5 ) group in ethanol is non-polar. Having a polar and non-polar group, ethanol can dissolve both polar molecules, such as water and non-polar molecules such as hexane. Ethanol is used as a solvent in foods and consumer products such as perfumes and is toxic only in large doses.
Ethanol can be produced in a number of different organic reaction pathways The biological process of fermentation is another source of ethanol. This process is predominantly carried out by microscopic fungi called yeast, pictured on the right. Although the process is complex, we will simplify fermentation by representing it as the overall process by which glucose (C 6 H 12 O 6 ) is converted into ethanol (CH 3 CH 2 OH) and carbon dioxide gas (CO 2 ). C 6 H 12 O 6 => 2CH 3 CH 2 OH + 2CO 2 + Energy (ATP) Ethanol is toxic to yeast and can only be tolerated at concentrations below 15% (v/v). Image from www.acad.carleton.edu/curricular/BIOL/faculty/szweifel/ Ethanol is considered a renewable energy source because it is produced by the chemical breakdown of sugars that are produced during the process of photosynthesis. The overall reaction of photosynthesis is shown below.6H 2 O + 6CO 2 + Energy => C 6 H 12 O 6 + 6O 2 The cellulose in plant matter, such as sugar cane waste, can be broken down by bacteria and the sugars then fermented to produce ethanol. Synthesis of ethanol and subsequent purification, is energy consuming and the thought of ethanol as a viable, green energy alternative is negated by the energy used in its production. Ethanol as a fuel is mixed with petrol where 85% of the fuel is composed of ethanol. By 2009 over six million “dual-fuel” ethanol-compliant cars and trucks, had been manufactured in America, however, a lack of filling stations means that most of these vehicles run on petrol most of the time. The combustion of ethanol, shown below, releases heat energy which drives the pistons of the vehicle. CH 3 CH 2 OH + 3 O 2 → 2 CO 2 + 3 H 2 O + heat Image from Google Read this article and summarise the concern with the use of ethanol as a fuel. The products of fermentation are Hexane is a non-polar substance. Which of the following is the orientation of ethanol in hexane? Explain. Why is ethanol used as a solvent for polar and non polar substances? Describe the inter-molecular bonding in ethanol. Would you expect ethanol to dissolve in water? Explain. What is the process by which ethanol is purified? Why is this process high in energy consumption? A student set up a flask with a sugar solution and yeast and conducted an alcoholic fermentation The flask was placed on top of an electronic balance and the mass of the set up was determined every hour. The table on the right shows the data the student recorded. a) What are the dependent and independent variables in this experiment? b) Graph the results on an appropriate set of axis. i) What will represent the y- axis? ii) What will represent the x-axis? c) What do you attribute to the mass loss? d) How many hours into the experiment does the rate of fermentation peak? e) Why does mass loss plateau after 6 hours of fermentation? f) What volume of gas was produced by the yeast at SLC during the 9 hours of fermentation?
Is ethanol soluble in water?
Predicting Solubility – The dividing line between what we call soluble and what we call insoluble is arbitrary, but the following are common criteria for describing substances as insoluble, soluble, or moderately soluble.
- If less than 1 gram of the substance will dissolve in 100 milliliters (or 100 g) of solvent, the substance is considered insoluble.
- If more than 10 grams of substance will dissolve in 100 milliliters (or 100 g) of solvent, the substance is considered soluble.
- If between 1 and 10 grams of a substance will dissolve in 100 milliliters (or 100 g) of solvent, the substance is considered moderately soluble.
Although it is difficult to determine specific solubilities without either finding them by experiment or referring to a table of solubilities, we do have guidelines that allow us to predict relative solubilities. Principal among these is Like dissolves like.
For example, this guideline could be used to predict that ethanol, which is composed of polar molecules, would be soluble in water, which is also composed of polar molecules. Likewise, pentane (C5H12), which has nonpolar molecules, is miscible with hexane, which also has nonpolar molecules. We will use the Like Dissolve Like guideline to predict whether a substance is likely to be more soluble in water or in hexane.
It can also be used to predict which of two substances is likely to be more soluble in water and which of two substances is likely to be more soluble in a nonpolar solvent, such as hexane: Polar substances are likely to dissolve in polar solvents. For example, ionic compounds, which are very polar, are often soluble in the polar solvent water.
- Nonpolar substances are likely to dissolve in nonpolar solvents.
- For example, nonpolar molecular substances are likely to dissolve in hexane, a common nonpolar solvent.
- Two additional guidelines are derived from these: Nonpolar substances are not likely to dissolve to a significant degree in polar solvents.
For example, nonpolar molecular substances, like hydrocarbons, are likely to be insoluble in water. Polar substances are not likely to dissolve to a significant degree in nonpolar solvents. For example, ionic compounds are insoluble in hexane. It is more difficult to predict the solubility of polar molecular substances than to predict the solubility of ionic compounds and nonpolar molecular substances.
Is ethanol very soluble in water?
Solubility – Virtually all of the organic chemistry that you will see in this course takes place in the solution phase. In the organic laboratory, reactions are often run in nonpolar or slightly polar solvents such as toluene (methylbenzene), hexane, dichloromethane, or diethylether.
- In recent years, much effort has been made to adapt reaction conditions to allow for the use of ‘greener’ (in other words, more environmentally friendly) solvents such as water or ethanol, which are polar and capable of hydrogen bonding.
- In organic reactions that occur in the cytosolic region of a cell, the solvent is of course water.
It is critical for any organic chemist to understand the factors which are involved in the solubility of different molecules in different solvents. You probably remember the rule you learned in general chemistry regarding solubility: ‘like dissolves like’ (and even before you took any chemistry at all, you probably observed at some point in your life that oil does not mix with water).
- Let’s revisit this old rule, and put our knowledge of covalent and noncovalent bonding to work.
- Imagine that you have a flask filled with water, and a selection of substances that you will test to see how well they dissolve in the water.
- The first substance is table salt, or sodium chloride.
- As you would almost certainly predict, especially if you’ve ever inadvertently taken a mouthful of water while swimming in the ocean, this ionic compound dissolves readily in water.
Why? Because water, as a very polar molecule, is able to form many ion-dipole interactions with both the sodium cation and the chloride anion, the energy from which is more than enough to make up for energy required to break up the ion-ion interactions in the salt crystal and some water-water hydrogen bonds. The end result, then, is that in place of sodium chloride crystals, we have individual sodium cations and chloride anions surrounded by water molecules – the salt is now in solution, Charged species as a rule dissolve readily in water: in other words, they are very hydrophilic (water-loving). Biphenyl does not dissolve at all in water. Why is this? Because it is a very non-polar molecule, with only carbon-carbon and carbon-hydrogen bonds. It is able to bond to itself very well through nonpolar van der Waals interactions, but it is not able to form significant attractive interactions with the very polar solvent molecules. You find that the smaller alcohols – methanol, ethanol, and propanol – dissolve easily in water. This is because the water is able to form hydrogen bonds with the hydroxyl group in these molecules, and the combined energy of formation of these water-alcohol hydrogen bonds is more than enough to make up for the energy that is lost when the alcohol-alcohol hydrogen bonds are broken up.
When you try butanol, however, you begin to notice that, as you add more and more to the water, it starts to form its own layer on top of the water. The longer-chain alcohols – pentanol, hexanol, heptanol, and octanol – are increasingly non-soluble. What is happening here? Clearly, the same favorable water-alcohol hydrogen bonds are still possible with these larger alcohols.
The difference, of course, is that the larger alcohols have larger nonpolar, hydrophobic regions in addition to their hydrophilic hydroxyl group. At about four or five carbons, the hydrophobic effect begins to overcome the hydrophilic effect, and water solubility is lost. We have tipped the scales to the hydrophilic side, and we find that glucose is quite soluble in water. We saw that ethanol was very water-soluble (if it were not, drinking beer or vodka would be rather inconvenient!) How about dimethyl ether, which is a constitutional isomer of ethanol but with an ether rather than an alcohol functional group? We find that diethyl ether is much less soluble in water. The result is that the alcohol is able to form more energetically favorable interactions with the solvent compared to the ether, and the alcohol is therefore more soluble. Here is another easy experiment that can be done (with proper supervision) in an organic laboratory. Acetic acid, however, is quite soluble. This is easy to explain using the small alcohol vs large alcohol argument: the hydrogen-bonding, hydrophilic effect of the carboxylic acid group is powerful enough to overcome the hydrophobic effect of a single methyl group on acetic acid, but not the larger hydrophobic effect of the 6-carbon benzene group on benzoic acid. What is happening here is that the benzoic acid is being converted to its conjugate base, benzoate. The neutral carboxylic acid group was not hydrophilic enough to make up for the hydrophobic benzene ring, but the carboxylate group, with its full negative charge, is much more hydrophilic.
Now, the balance is tipped in favor of water solubility, as the powerfully hydrophilic anion part of the molecule drags the hydrophobic part, kicking and screaming, (if a benzene ring can kick and scream) into solution. If you want to precipitate the benzoic acid back out of solution, you can simply add enough hydrochloric acid to neutralize the solution and reprotonate the carboxylate.
If you are taking a lab component of your organic chemistry course, you will probably do at least one experiment in which you will use this phenomenon to separate an organic acid like benzoic acid from a hydrocarbon compound like biphenyl. Similar arguments can be made to rationalize the solubility of different organic compounds in nonpolar or slightly polar solvents.
|Exercise 2.12 : Vitamins can be classified as water-soluble or fat-soluble (consider fat to be a very non-polar, hydrophobic ‘solvent’. Decide on a classification for each of the vitamins shown below. Exercise 2.13 : Both aniline and phenol are insoluble in pure water. Predict the solubility of these two compounds in 10% aqueous hydrochloric acid, and explain your reasoning. Hint – in this context, aniline is basic, phenol is not! Solutions
Why is ethanol soluble in water?
Ethanol is an organic compound that contains a hydroxyl group as a functional group. Ethanol is a clear colourless liquid.
Solubility of ethanol in water:
Ethanol has a hydroxyl(-OH) functional group in it.Due to the presence of a bond between electronegative atom oxygen and hydrogen, the O-H bond acquires polarity.Hence, due to the presence of polarity in O-H bond, it forms a Hydrogen bond with water which is responsible for the responsibility of ethanol in water.
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Is ethanol lipid or water soluble?
Alcohol distributes into water spaces, not fat – Because ethanol is soluble in water it moves into water spaces throughout the body. The water spaces include the bloodstream, extracellular spaces, and intracellular spaces. However, ethanol does not accumulate in adipose tissue (fat) because it has little non-polar character and it prefers to reside in water. Figure 1.9 Females have a lower percentage of water (and higher percentage of fat) in the body. This means females will have a higher BAC compared to males if they drink the same amount of alcohol. On average, the total body water in females is 55% of their body mass compared with that in males, which is 68%.
Of course there are some exceptions—a lean female athlete would be expected to have a higher percent of total body water than an obese male. As the percentage of body fat increases, the BAC increases—this is because the total body water is lower, and that means that the alcohol is confined to this smaller volume.
This relationship is familiar—concentration can be expressed as mass per unit volume (C = M/V). Concentration is indirectly proportional to volume—the smaller the water volume in the body, the higher the concentration of alcohol in the water spaces.
The higher BAC in females puts them at greater risk of intoxication compared to males, since more alcohol reaches the brain. about how alcohol produces intoxication.For the same drink, females will have a higher BAC than males because they have a higher percentage of body fat relative to males.
: Where Does Alcohol Go in the Body? – The Alcohol Pharmacology Education Partnership