A solvent (from the Latin solvō, "loosen, untie, solve") is a
substance that dissolves a solute (a chemically distinct liquid, solid
or gas), resulting in a solution. A solvent is usually a liquid but
can also be a solid, a gas, or a supercritical fluid. The quantity of
solute that can dissolve in a specific volume of solvent varies with
temperature. Common uses for organic solvents are in dry cleaning
(e.g. tetrachloroethylene), as paint thinners (e.g. toluene,
turpentine), as nail polish removers and glue solvents (acetone,
methyl acetate, ethyl acetate), in spot removers (e.g. hexane, petrol
ether), in detergents (citrus terpenes) and in perfumes (ethanol).
Water is a solvent for polar molecules and the most common solvent
used by living things; all the ions and proteins in a cell are
dissolved in water within a cell. Solvents find various applications
in chemical, pharmaceutical, oil, and gas industries, including in
chemical syntheses and purification processes.
1 Solutions and solvation
2.1 Other polarity scales
2.2 Polar protic and polar aprotic
4 Physical properties
4.1 Properties table of common solvents
4.1.2 Polar aprotic solvents
4.1.3 Polar protic solvents
Hansen solubility parameter values
4.2.1 Non-polar solvents
4.2.2 Polar aprotic solvents
4.2.3 Polar protic solvents
4.3 Boiling point
5.2 Explosive peroxide formation
6 Health effects
6.1 Acute exposure
6.2 Chronic exposure
6.3 Environmental contamination
7 See also
10 External links
Solutions and solvation
When one substance is dissolved into another, a solution is formed.
This is opposed to the situation when the compounds are insoluble like
sand in water. In a solution, all of the ingredients are uniformly
distributed at a molecular level and no residue remains. A
solvent-solute mixture consists of a single phase with all solute
molecules occurring as solvates (solvent-solute complexes), as opposed
to separate continuous phases as in suspensions, emulsions and other
types of non-solution mixtures. The ability of one compound to be
dissolved in another is known as solubility; if this occurs in all
proportions, it is called miscible.
In addition to mixing, the substances in a solution interact with each
other at the molecular level. When something is dissolved, molecules
of the solvent arrange around molecules of the solute. Heat transfer
is involved and entropy is increased making the solution more
thermodynamically stable than the solute and solvent separately. This
arrangement is mediated by the respective chemical properties of the
solvent and solute, such as hydrogen bonding, dipole moment and
Solvation does not cause a chemical reaction or
chemical configuration changes in the solute. However, solvation
resembles a coordination complex formation reaction, often with
considerable energetics (heat of solvation and entropy of solvation)
and is thus far from a neutral process.
Solvents can be broadly classified into two categories: polar and
non-polar. A special case is mercury, whose solutions are known as
amalgams; also, other metal solutions exist which are liquid at room
temperature. Generally, the dielectric constant of the solvent
provides a rough measure of a solvent's polarity. The strong polarity
of water is indicated by its high dielectric constant of 88 (at
0 °C). Solvents with a dielectric constant of less than 15
are generally considered to be nonpolar. The dielectric constant
measures the solvent's tendency to partly cancel the field strength of
the electric field of a charged particle immersed in it. This
reduction is then compared to the field strength of the charged
particle in a vacuum. Heuristically, the dielectric constant of a
solvent can be thought of as its ability to reduce the solute's
effective internal charge. Generally, the dielectric constant of a
solvent is an acceptable predictor of the solvent's ability to
dissolve common ionic compounds, such as salts.
Other polarity scales
Dielectric constants are not the only measure of polarity. Because
solvents are used by chemists to carry out chemical reactions or
observe chemical and biological phenomena, more specific measures of
polarity are required. Most of these measures are sensitive to
The Grunwald–Winstein mY scale measures polarity in terms of solvent
influence on buildup of positive charge of a solute during a chemical
Kosower's Z scale measures polarity in terms of the influence of the
solvent on UV-absorption maxima of a salt, usually pyridinium iodide
or the pyridinium zwitterion.
Donor number and donor acceptor scale measures polarity in terms of
how a solvent interacts with specific substances, like a strong Lewis
acid or a strong Lewis base.
Hildebrand parameter is the square root of cohesive energy
density. It can be used with nonpolar compounds, but cannot
accommodate complex chemistry.
Reichardt's dye, a solvatochromic dye that changes color in response
to polarity, gives a scale of ET(30) values. ET is the transition
energy between the ground state and the lowest excited state in
kcal/mol, and (30) identifies the dye. Another, roughly correlated
scale (ET(33)) can be defined with Nile red.
The polarity, dipole moment, polarizability and hydrogen bonding of a
solvent determines what type of compounds it is able to dissolve and
with what other solvents or liquid compounds it is miscible.
Generally, polar solvents dissolve polar compounds best and non-polar
solvents dissolve non-polar compounds best: "like dissolves like".
Strongly polar compounds like sugars (e.g. sucrose) or ionic
compounds, like inorganic salts (e.g. table salt) dissolve only in
very polar solvents like water, while strongly non-polar compounds
like oils or waxes dissolve only in very non-polar organic solvents
like hexane. Similarly, water and hexane (or vinegar and vegetable
oil) are not miscible with each other and will quickly separate into
two layers even after being shaken well.
Polarity can be separated to different contributions. For example, the
Kamlet-Taft parameters are dipolarity/polarizability (π*),
hydrogen-bonding acidity (α) and hydrogen-bonding basicity (β).
These can be calculated from the wavelength shifts of 3–6 different
solvatochromic dyes in the solvent, usually including Reichardt's dye,
nitroaniline and diethylnitroaniline. Another option, Hansen's
parameters, separate the cohesive energy density into dispersion,
polar and hydrogen bonding contributions.
Polar protic and polar aprotic
Solvents with a dielectric constant (more accurately, relative static
permittivity) greater than 15 (i.e. polar or polarizable) can be
further divided into protic and aprotic.
Protic solvents solvate
anions (negatively charged solutes) strongly via hydrogen bonding.
Water is a protic solvent.
Aprotic solvents such as acetone or
dichloromethane tend to have large dipole moments (separation of
partial positive and partial negative charges within the same
molecule) and solvate positively charged species via their negative
dipole. In chemical reactions the use of polar protic solvents
SN1 reaction mechanism, while polar aprotic solvents favor
SN2 reaction mechanism. These polar solvents are capable of
forming hydrogen bonds with water to dissolve in water whereas non
polar solvents are not capable of strong hydrogen bonds.
Russia and other CIS countries, there are mainly multicomponent
solvents on sale in the markets. They are known, produced and sold by
their respective numbers (Russian: Растворитель X, meaning
Solvent X") throughout CIS countries. It is the combination of
substances that causes the large functionality of these products and
their consumer properties.
Solvents are known by their Russian name "Rastvoritel" (Russian:
toluene 50%, butyl acetate 18%, ethyl acetate 12%, butanol 10%,
toluene 50%, ethanol 15%, butanol 10%, butyl- or amyl acetate 10%,
ethyl cellosolve 8%, acetone 7% 
butyl- or amyl acetate 29.8%, ethyl acetate 21.2%, butanol 7.7%,
toluene or pyrobenzene 41.3% 
butyl acetate 50%, ethanol 10%, butanol 20%, toluene 20% 
ethyl cellosolve 30%, butanol 20%, xylene 50%
ethyl cellosolve 20%, butanol 30%, xylene 50% 
white spirit 90%, butanol 10%
butyl acetate 20%, butanol 80%
toluene 62%, acetone 26%, butyl acetate 12%.
xylene 85%, acetone 15%.
toluene 60%, butyl acetate 30%, xylene 10%.
cyclohexanone 50%, toluene 50%.
solvent 50%, xylene 35%, acetone 15%.
toluene 50%, ethyl cellosolve 30%, acetone 20%.
toluene 34%, cyclohexanone 33%, acetone 33%.
butanol 60%, ethanol 40%.
xylene 90%, butyl acetate 10%.
ethanol 64%, ethylcellosolve 16%, toluene 10%, butanol 10%.
toluene 25%, xylene 25%, butyl acetate 18%, ethyl cellosolve 17%,
toluene 60%, butyl acetate 30%, xylene 10%.
white spirit 70%, xylene 30%.
ethanol 75%, butanol 25%.
xylene 50%, acetone 20%, butanol 15%, ethanol 15%.
Solvent 70%, ethanol 20%, acetone 10%.
solvent 50%, ethanol 20%, acetone 20%, ethyl cellosolve 10%.
solvent 50%, acetone 30%, ethanol 20%.
Solvent FK-1 (?)
absolute alcohol (99.8%) 95%, ethyl acetate 5%
Thinners are known by their Russian name "Razbavitel" (Russian:
butanol 50%, xylene 50%
butanol 95%, xylene 5%
xylene 90%, butanol 10%
ethanol 65%, butyl acetate 30%, ethyl acetate 5%.
cyclohexanone 50%, ethanol 50%.
xylene 60%, butyl acetate 20%, ethyl cellosolve 20%.
Thinner of WFD
toluene 50%, butyl acetate (or amyl acetate) 18%, butanol 10%, ethanol
10%, ethyl acetate 9%, acetone 3%.
Properties table of common solvents
The solvents are grouped into nonpolar, polar aprotic, and polar
protic solvents, ordered by increasing polarity. The polarity is given
as the dielectric constant. The properties of solvents which exceed
those of water are bolded.
displaystyle ce (C2H4O)2
Polar aprotic solvents
displaystyle ce (CH2)4O
Dimethyl sulfoxide (DMSO)
Polar protic solvents
Isopropyl alcohol (IPA)
Hansen solubility parameter values
Hansen solubility parameter values are based on dispersion
bonds (δD), polar bonds (δP) and hydrogen bonds (δH). These contain
information about the inter-molecular interactions with other solvents
and also with polymers, pigments, nanoparticles, etc. This allows for
rational formulations knowing, for example, that there is a good HSP
match between a solvent and a polymer. Rational substitutions can also
be made for "good" solvents (effective at dissolving the solute) that
are "bad" (expensive or hazardous to health or the environment). The
following table shows that the intuitions from "non-polar", "polar
aprotic" and "polar protic" are put numerically – the "polar"
molecules have higher levels of δP and the protic solvents have
higher levels of δH. Because numerical values are used, comparisons
can be made rationally by comparing numbers. For example, acetonitrile
is much more polar than acetone but exhibits slightly less hydrogen
Polar aprotic solvents
Dimethyl sulfoxide (DMSO)
Polar protic solvents
If, for environmental or other reasons, a solvent or solvent blend is
required to replace another of equivalent solvency, the substitution
can be made on the basis of the
Hansen solubility parameters of each.
The values for mixtures are taken as the weighted averages of the
values for the neat solvents. This can be calculated by
trial-and-error, a spreadsheet of values, or HSP software. A
1:1 mixture of toluene and
1,4 dioxane has δD, δP and δH values of
17.8, 1.6 and 5.5, comparable to those of chloroform at 17.8, 3.1 and
5.7 respectively. Because of the health hazards associated with
toluene itself, other mixtures of solvents may be found using a full
Boiling point (°C)
methyl isobutyl ketone
The boiling point is an important property because it determines the
speed of evaporation. Small amounts of low-boiling-point solvents like
diethyl ether, dichloromethane, or acetone will evaporate in seconds
at room temperature, while high-boiling-point solvents like water or
dimethyl sulfoxide need higher temperatures, an air flow, or the
application of vacuum for fast evaporation.
Low boilers: boiling point below 100 °C (boiling point of water)
Medium boilers: between 100 °C and 150 °C
High boilers: above 150 °C
Most organic solvents have a lower density than water, which means
they are lighter than and will form a layer on top of water. Important
exceptions are most of the halogenated solvents like dichloromethane
or chloroform will sink to the bottom of a container, leaving water as
the top layer. This is crucial to remember when partitioning compounds
between solvents and water in a separatory funnel during chemical
Often, specific gravity is cited in place of density. Specific gravity
is defined as the density of the solvent divided by the density of
water at the same temperature. As such, specific gravity is a unitless
value. It readily communicates whether a water-insoluble solvent will
float (SG < 1.0) or sink (SG > 1.0) when mixed with water.
Tert-butyl methyl ether
Methyl isobutyl ketone
Methyl ethyl ketone
Diethylene glycol dimethyl ether
Most organic solvents are flammable or highly flammable, depending on
their volatility. Exceptions are some chlorinated solvents like
dichloromethane and chloroform. Mixtures of solvent vapors and air can
Solvent vapors are heavier than air; they will sink to the
bottom and can travel large distances nearly undiluted.
can also be found in supposedly empty drums and cans, posing a flash
fire hazard; hence empty containers of volatile solvents should be
stored open and upside down.
Both diethyl ether and carbon disulfide have exceptionally low
autoignition temperatures which increase greatly the fire risk
associated with these solvents. The autoignition temperature of carbon
disulfide is below 100 °C (212 °F), so objects such as
steam pipes, light bulbs, hotplates, and recently-extinguished bunsen
burners are able to ignite its vapours.
In addition some solvents, such as methanol, can burn with a very hot
flame which can be nearly invisible under some lighting
conditions. This can delay or prevent the timely recognition
of a dangerous fire, until flames spread to other materials.
Explosive peroxide formation
Ethers like diethyl ether and tetrahydrofuran (THF) can form highly
explosive organic peroxides upon exposure to oxygen and light. THF is
normally more likely to form such peroxides than diethyl ether. One of
the most susceptible solvents is diisopropyl ether, but all ethers are
considered to be potential peroxide sources.
The heteroatom (oxygen) stabilizes the formation of a free radical
which is formed by the abstraction of a hydrogen atom by another free
radical.[clarification needed] The carbon-centred free radical thus
formed is able to react with an oxygen molecule to form a peroxide
compound. The process of peroxide formation is greatly accelerated by
exposure to even low levels of light, but can proceed slowly even in
Unless a desiccant is used which can destroy the peroxides, they will
concentrate during distillation, due to their higher boiling point.
When sufficient peroxides have formed, they can form a crystalline,
shock-sensitive solid precipitate at the mouth of a container or
bottle. Minor mechanical disturbances, such as scraping the inside of
a vessel or the dislodging of a deposit, merely twisting the cap may
provide sufficient energy for the peroxide to explode or detonate.
Peroxide formation is not a significant problem when fresh solvents
are used up quickly; they are more of a problem in laboratories which
may take years to finish a single bottle. Low-volume users should
acquire only small amounts of peroxide-prone solvents, and dispose of
old solvents on a regular periodic schedule.
To avoid explosive peroxide formation, ethers should be stored in an
aritight container, away from light, because both light and air can
encourage peroxide formation.
A number of tests can be used to detect the presence of a peroxide in
an ether; one is to use a combination of iron(II) sulfate and
potassium thiocyanate. The peroxide is able to oxidize the Fe2+ ion to
an Fe3+ ion, which then forms a deep-red coordination complex with the
Peroxides may be removed by washing with acidic iron(II) sulfate,
filtering through alumina, or distilling from sodium/benzophenone.
Aluminum does not destroy the peroxides but merely traps them, and
must be disposed of properly. The advantage of using
sodium/benzophenone is that moisture and oxygen are removed as
General health hazards associated with solvent exposure include
toxicity to the nervous system, reproductive damage, liver and kidney
damage, respiratory impairment, cancer, and dermatitis.
Many solvents can lead to a sudden loss of consciousness if inhaled in
large amounts. Solvents like diethyl ether and chloroform have been
used in medicine as anesthetics, sedatives, and hypnotics for a long
Ethanol (grain alcohol) is a widely used and abused psychoactive
drug. Diethyl ether, chloroform, and many other solvents e.g. from
gasoline or glues are abused recreationally in glue sniffing, often
with harmful long term health effects like neurotoxicity or cancer.
Fraudulent substitution of
1,5-pentanediol for the psychoactive
1,4-butanediol by a subcontractor caused the
If ingested, the so called toxic alcohols (other than ethanol) such as
methanol, propanol, and ethylene glycol metabolize into toxic
aldehydes and acids, which cause potentially fatal metabolic acidosis.
 The commonly available alcohol solvent methanol can cause
permanent blindness or death if ingested. The solvent 2-butoxyethanol,
used in fracking fluids, can cause hypotension and metabolic
Main article: Chronic solvent-induced encephalopathy
Some solvents including chloroform and benzene a common ingredient in
gasoline are known to be carcinogenic, while many others are
considered by the
World Health Organization
World Health Organization to be likely carcinogens.
Solvents can damage internal organs like the liver, the kidneys, the
nervous system, or the brain. The cumulative effects of long-term or
repeated exposure to solvents are called chronic solvent-induced
Chronic exposure to organic solvents in the work environment can
produce a range of adverse neuropsychiatric effects. For example,
occupational exposure to organic solvents has been associated with
higher numbers of painters suffering from alcoholism.
a synergistic effect when taken in combination with many solvents; for
instance, a combination of toluene/benzene and ethanol causes greater
nausea/vomiting than either substance alone.
Many solvents are known or suspected to be cataractogenic, greatly
increasing the risk of developing cataracts in the lens of the
Solvent exposure has also been associated with neurotoxic
damage causing hearing loss and color vision losses.
A major pathway to induce health effects arises from spills or leaks
of solvents that reach the underlying soil. Since solvents readily
migrate substantial distances, the creation of widespread soil
contamination is not uncommon; this is particularly a health risk if
aquifers are affected. There may be about 5000 sites worldwide that
have major subsurface solvent contamination.
Wikimedia Commons has media related to Solvents.
Free energy of solvation
Solvents are often refluxed with an appropriate desiccant prior to
distillation to remove water. This may be performed prior to a
chemical synthesis where water may interfere with the intended
List of water-miscible solvents
Partition coefficient (log P) is a measure of differential solubility
of a compound in two solvents
Solvent systems exist outside the realm of ordinary organic solvents:
Supercritical fluids, ionic liquids and deep eutectic solvents
^ Tinoco, Ignacio; Sauer, Kenneth and Wang, James C. (2002) Physical
Chemistry Prentice Hall p. 134 ISBN 0-13-026607-8
^ Lowery and Richardson, pp. 181–183
^ Malmberg, C. G.; Maryott, A. A. (January 1956). "Dielectric Constant
of Water from 0° to 100°C" (PDF). Journal of Research of the
National Bureau of Standards. 56 (1): 1. doi:10.6028/jres.056.001.
Archived (PDF) from the original on 19 August 2014. Retrieved 27 June
^ a b Lowery and Richardson, p. 177.
^ Kosower, E.M. (1969) "An introduction to Physical Organic Chemistry"
Wiley: New York, p. 293
^ Gutmann, V. (1976). "
Solvent effects on the reactivities of
organometallic compounds". Coord. Chem. Rev. 18 (2): 225.
^ Lowery and Richardson, p. 183.
Solvent 646 Characteristics (ru)
Solvent 647 Characteristics (ru)
Solvent 648 Characteristics (ru)
Solvent 650 Characteristics (ru)
^ a b
Solvent Properties – Boiling Point Archived 14 June 2011 at
the Wayback Machine.. Xydatasource.com. Retrieved on 2013-01-26.
^ Dielectric Constant Archived 4 July 2010 at the Wayback Machine..
Macro.lsu.edu. Retrieved on 2013-01-26.
^ a b Abbott, Steven and Hansen, Charles M. (2008) Hansen Hansen
Solubility Parameters in Practice Archived 29 July 2016 at the Wayback
Machine., ISBN 0-9551220-2-3
^ a b Hansen, Charles M. (2007) Hansen solubility parameters: a user's
handbook Archived 25 June 2016 at the Wayback Machine. CRC Press,
^ Selected solvent properties – Specific Gravity Archived 14 June
2011 at the Wayback Machine.. Xydatasource.com. Retrieved on
^ Fanick, E. Robert; Smith, Lawrence R.; Baines, Thomas M. (1 October
1984). "Safety Related Additives for
Methanol Fuel". Warrendale, PA.
Archived from the original on 12 August 2017.
^ Anderson, J. E.; Magyarl, M. W.; Siegl, W. O. (1985-07-01).
"Concerning the Luminosity of Methanol-Hydrocarbon Diffusion Flames".
Combustion Science and Technology. 43 (3-4): 115–125.
doi:10.1080/00102208508947000. ISSN 0010-2202.
^ "Peroxides and Ethers Environmental Health, Safety and Risk
Management". www.uaf.edu. Retrieved 2018-01-25.
^ U.S. Department of Labor > Occupational Safety & Health
Administration > Solvents Archived 15 March 2016 at the Wayback
^ J.A. Kraut, M.E. Mullins Toxic Alcohols - Review N Engl J Med
^ Hung, Tawny; Dewitt, Christopher R.; Martz, Walter; Schreiber,
William; Holmes, Daniel Thomas (July 2010). "Fomepizole fails to
prevent progression of acidosis in
2-Butoxyethanol and ethanol
coingestion". Clinical Toxicology. 48 (6): 569–571.
doi:10.3109/15563650.2010.492350. PMID 20560787.
^ Lundberg I, Gustavsson A, Högberg M, Nise G (1992). "Diagnoses of
alcohol abuse and other neuropsychiatric disorders among house
painters compared with house carpenters". Br J Ind Med. 49 (6):
409–15. doi:10.1136/oem.49.6.409. PMC 1012122 .
^ Raitta, C; Husman, K; Tossavainen, A (1976). "Lens changes in car
painters exposed to a mixture of organic solvents". Albrecht von
Graefes Archiv für klinische und experimentelle Ophthalmologie. 200
(2): 149–56. doi:10.1007/bf00414364. PMID 1086605.
^ Campo, Pierre; Morata, Thais C.; Hong, OiSaeng. "Chemical exposure
and hearing loss". Disease-a-Month. 59 (4): 119–138.
doi:10.1016/j.disamonth.2013.01.003. PMC 4693596 .
PMID 23507352. Archived from the original on 21 December
^ Johnson AC and Morata,, TC (2010). "Occupational exposure to
chemicals and hearing impairment. The Nordic Expert Group for Criteria
Documentation of Health Risks from Chemicals" (PDF). Arbete och
Hälsa. 44: 177. Archived (PDF) from the original on 4 June
^ Mergler, D; Blain, L; Lagacé, J. P. (1987). "
Solvent related colour
vision loss: An indicator of neural damage?". International Archives
of Occupational and Environmental Health. 59 (4): 313–21.
doi:10.1007/bf00405275. PMID 3497110.
Lowery, T.H. and Richardson, K.S., Mechanism and Theory in Organic
Harper Collins Publishers
Harper Collins Publishers 3rd ed. 1987
Look up solvent in Wiktionary, the free dictionary.
 Solvents in Europe.
Table and text O-Chem Lecture
Tables Properties and toxicities of organic solvents
CDC – Organic Solvents – NIOSH Workplace Safety and Health Topic
Solvent Contaminated Wipes
Basic reaction mechanisms
Unimolecular nucleophilic substitution (SN1)
Bimolecular nucleophilic substitution (SN2)
Nucleophilic aromatic substitution
Nucleophilic aromatic substitution (SNAr)
Nucleophilic internal substitution (SNi)
Nucleophilic acyl substitution
Unimolecular elimination (E1)
Bimolecular elimination (E2)
Articles related to solutions
Apparent molar property
and related quantities
Total dissolved solids
Enthalpy of solution
Solubility table (data)
Acid dissociation constant
Inorganic nonaqueous solvent
List of boiling and freezing information of solvents