Solvent

A solvent (from the

are dissolved in water within the cell.

Major uses of solvents are in paints, paint removers, inks, and dry cleaning.

and purification processes.

Solutions and solvation

When one substance is

.

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

formation reaction, often with considerable energetics (heat of solvation and entropy of solvation) and is thus far from a neutral process.

When one substance dissolves into another, a solution is formed. A solution is a homogeneous mixture consisting of a solute dissolved into a solvent. The solute is the substance that is being dissolved, while the solvent is the dissolving medium. Solutions can be formed with many different types and forms of solutes and solvents.

Solvent classifications

Solvents can be broadly classified into two categories: polar and non-polar. A special case is elemental mercury, whose solutions are known as amalgams; also, other metal solutions exist which are liquid at room temperature.

Generally, the

The dielectric constant measures the solvent's tendency to partly cancel the field strength of the electric field of a

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 chemical structure.

The Grunwald–Winstein mY scale measures polarity in terms of solvent influence on buildup of positive charge of a solute during a chemical reaction.

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.^[7]

Donor number and donor acceptor scale measures polarity in terms of how a solvent interacts with specific substances, like a strong

The

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

.

The polarity, dipole moment, polarizability and

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 solubility parameters, separates the cohesive energy density into dispersion, polar, and hydrogen bonding contributions.

Polar protic and polar aprotic

Solvents with a dielectric constant (more accurately,

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.

Physical properties

Properties table of common solvents

The solvents are grouped into

of solvents which exceed those of water are bolded.

Solvent	Chemical formula	Boiling point[10] (°C)	Dielectric constant[11]	Density (g/mL)	Dipole moment (D )
Nonpolar hydrocarbon solvents
Pentane	CH3CH2CH2CH2CH3	36.1	1.84	0.626	0.00
Hexane	CH3CH2CH2CH2CH2CH3	69	1.88	0.655	0.00
Benzene	C6H6	80.1	2.3	0.879	0.00
Heptane	H3C(CH2)5CH3	98.38	1.92	0.680	0.0
Toluene	C6H5-CH3	111	2.38	0.867	0.36
Nonpolar ether solvents
1,4-Dioxane	C4H8O2	101.1	2.3	1.033	0.45
Diethyl ether	CH3CH2-O-CH2CH3	34.6	4.3	0.713	1.15
Tetrahydrofuran (THF)	C4H8O	66	7.5	0.886	1.75
Nonpolar chlorocarbon solvents
Chloroform	CHCl3	61.2	4.81	1.498	1.04
Polar aprotic solvents
Dichloromethane (DCM)	CH2Cl2	39.6	9.1	1.3266	1.60
Ethyl acetate	CH3-C(=O)-O-CH2-CH3	77.1	6.02	0.894	1.78
Acetone	CH3-C(=O)-CH3	56.1	21	0.786	2.88
Dimethylformamide (DMF)	H-C(=O)N(CH3)2	153	38	0.944	3.82
Acetonitrile (MeCN)	CH3-C≡N	82	37.5	0.786	3.92
Dimethyl sulfoxide (DMSO)	CH3-S(=O)-CH3	189	46.7	1.092	3.96
Nitromethane	CH3-NO2	100–103	35.87	1.1371	3.56
Propylene carbonate	C4H6O3	240	64.0	1.205	4.9
Polar protic solvents
Ammonia	NH3	-33.3	17	0.674 (at -33.3 °C)	1.42
Formic acid	H-C(=O)OH	100.8	58	1.21	1.41
n-Butanol	CH3CH2CH2CH2OH	117.7	18	0.810	1.63
Isopropyl alcohol (IPA)	CH3-CH(-OH)-CH3	82.6	18	0.785	1.66
n-Propanol	CH3CH2CH2OH	97	20	0.803	1.68
Ethanol	CH3CH2OH	78.2	24.55	0.789	1.69
Methanol	CH3OH	64.7	33	0.791	1.70
Acetic acid	CH3-C(=O)OH	118	6.2	1.049	1.74
Water	H-O-H	100	80	1.000	1.85

The ACS Green Chemistry Institute maintains a tool for the selection of solvents based on a principal component analysis of solvent properties.^[12]

Hansen solubility parameter values

The

, 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 bonding.

Solvent	Chemical formula	δD Dispersion	δP Polar	δH Hydrogen bonding
Non-polar solvents
n-Hexane	CH3CH2CH2CH2CH2CH3	14.9	0.0	0.0
Benzene	C6H6	18.4	0.0	2.0
Toluene	C6H5-CH3	18.0	1.4	2.0
Diethyl ether	CH3CH2-O-CH2CH3	14.5	2.9	4.6
Chloroform	CHCl3	17.8	3.1	5.7
1,4-Dioxane	/-CH2-CH2-O-CH2-CH2-O-\	17.5	1.8	9.0
Polar aprotic solvents
Ethyl acetate	CH3-C(=O)-O-CH2-CH3	15.8	5.3	7.2
Tetrahydrofuran (THF)	/-CH2-CH2-O-CH2-CH2-\	16.8	5.7	8.0
Dichloromethane	CH2Cl2	17.0	7.3	7.1
Acetone	CH3-C(=O)-CH3	15.5	10.4	7.0
Acetonitrile (MeCN)	CH3-C≡N	15.3	18.0	6.1
Dimethylformamide (DMF)	H-C(=O)N(CH3)2	17.4	13.7	11.3
Dimethyl sulfoxide (DMSO)	CH3-S(=O)-CH3	18.4	16.4	10.2
Polar protic solvents
Acetic acid	CH3-C(=O)OH	14.5	8.0	13.5
n-Butanol	CH3CH2CH2CH2OH	16.0	5.7	15.8
Isopropanol	CH3-CH(-OH)-CH3	15.8	6.1	16.4
n-Propanol	CH3CH2CH2OH	16.0	6.8	17.4
Ethanol	CH3CH2OH	15.8	8.8	19.4
Methanol	CH3OH	14.7	12.3	22.3
Formic acid	H-C(=O)OH	14.6	10.0	14.0
Water	H-O-H	15.5	16.0	42.3

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

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 HSP dataset.

Boiling point

Solvent	Boiling point (°C)[10]
ethylene dichloride	83.48
pyridine	115.25
methyl isobutyl ketone	116.5
methylene chloride	39.75
isooctane	99.24
carbon disulfide	46.3
carbon tetrachloride	76.75
o-xylene	144.42

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

Density

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 syntheses.

Often,

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.

Solvent	Specific gravity[15]
Pentane	0.626
Petroleum ether	0.656
Hexane	0.659
Heptane	0.684
Diethyl amine	0.707
Diethyl ether	0.713
Triethyl amine	0.728
Tert-butyl methyl ether	0.741
Cyclohexane	0.779
Tert-butyl alcohol	0.781
Isopropanol	0.785
Acetonitrile	0.786
Ethanol	0.789
Acetone	0.790
Methanol	0.791
Methyl isobutyl ketone	0.798
Isobutyl alcohol	0.802
1-Propanol	0.803
Methyl ethyl ketone	0.805
2-Butanol	0.808
Isoamyl alcohol	0.809
1-Butanol	0.810
Diethyl ketone	0.814
1-Octanol	0.826
p-Xylene	0.861
m-Xylene	0.864
Toluene	0.867
Dimethoxyethane	0.868
Benzene	0.879
Butyl acetate	0.882
1-Chlorobutane	0.886
Tetrahydrofuran	0.889
Ethyl acetate	0.895
o-Xylene	0.897
Hexamethylphosphorus triamide	0.898
2-Ethoxyethyl ether	0.909
N,N-Dimethylacetamide	0.937
Diethylene glycol dimethyl ether	0.943
N,N-Dimethylformamide	0.944
2-Methoxyethanol	0.965
Pyridine	0.982
Propanoic acid	0.993
Water	1.000
2-Methoxyethyl acetate	1.009
Benzonitrile	1.01
1-Methyl-2-pyrrolidinone	1.028
Hexamethylphosphoramide	1.03
1,4-Dioxane	1.033
Acetic acid	1.049
Acetic anhydride	1.08
Dimethyl sulfoxide	1.092
Chlorobenzene	1.1066
Deuterium oxide	1.107
Ethylene glycol	1.115
Diethylene glycol	1.118
Propylene carbonate	1.21
Formic acid	1.22
1,2-Dichloroethane	1.245
Glycerin	1.261
Carbon disulfide	1.263
1,2-Dichlorobenzene	1.306
Methylene chloride	1.325
Nitromethane	1.382
2,2,2-Trifluoroethanol	1.393
Chloroform	1.498
1,1,2-Trichlorotrifluoroethane	1.575
Carbon tetrachloride	1.594
Tetrachloroethylene	1.623

Multicomponent solvents

This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources in this section. Unsourced material may be challenged and removed. Find sources: "Solvent" – news · newspapers · books · scholar · JSTOR (January 2022) (Learn how and when to remove this template message)

Multicomponent solvents appeared after World War II in the

, and continue to be used and produced in the post-Soviet states. These solvents may have one or more applications, but they are not universal preparations.

Solvents

Name	Composition
Solvent 645	toluene 50%, butyl acetate 18%, ethyl acetate 12%, butanol 10%, ethanol 10%.
Solvent 646	ethyl cellosolve 8%, acetone 7%[16]
Solvent 647	butyl- or amyl acetate 29.8%, ethyl acetate 21.2%, butanol 7.7%, toluene or pyrobenzene 41.3%[17]
Solvent 648	butyl acetate 50%, ethanol 10%, butanol 20%, toluene 20%[18]
Solvent 649	ethyl cellosolve 30%, butanol 20%, xylene 50%
Solvent 650	ethyl cellosolve 20%, butanol 30%, xylene 50%[19]
Solvent 651	white spirit 90%, butanol 10%
Solvent KR-36	butyl acetate 20%, butanol 80%
Solvent R-4	toluene 62%, acetone 26%, butyl acetate 12%.
Solvent R-10	xylene 85%, acetone 15%.
Solvent R-12	toluene 60%, butyl acetate 30%, xylene 10%.
Solvent R-14	cyclohexanone 50%, toluene 50%.
Solvent R-24	solvent 50%, xylene 35%, acetone 15%.
Solvent R-40	toluene 50%, ethyl cellosolve 30%, acetone 20%.
Solvent R-219	toluene 34%, cyclohexanone 33%, acetone 33%.
Solvent R-3160	butanol 60%, ethanol 40%.
Solvent RCC	xylene 90%, butyl acetate 10%.
Solvent RML	ethanol 64%, ethylcellosolve 16%, toluene 10%, butanol 10%.
Solvent PML-315	toluene 25%, xylene 25%, butyl acetate 18%, ethyl cellosolve 17%, butanol 15%.
Solvent PC-1	toluene 60%, butyl acetate 30%, xylene 10%.
Solvent PC-2	white spirit 70%, xylene 30%.
Solvent RFG	ethanol 75%, butanol 25%.
Solvent RE-1	xylene 50%, acetone 20%, butanol 15%, ethanol 15%.
Solvent RE-2	petroleum spirits 70%, ethanol 20%, acetone 10%.
Solvent RE-3	petroleum spirits 50%, ethanol 20%, acetone 20%, ethyl cellosolve 10%.
Solvent RE-4	petroleum spirits 50%, acetone 30%, ethanol 20%.
Solvent FK-1 (?)	absolute alcohol (99.8%) 95%, ethyl acetate 5%

Thinners

Name	Composition
Thinner RKB-1	butanol 50%, xylene 50%
Thinner RKB-2	butanol 95%, xylene 5%
Thinner RKB-3	xylene 90%, butanol 10%
Thinner M	ethanol 65%, butyl acetate 30%, ethyl acetate 5%.
Thinner P-7	cyclohexanone 50%, ethanol 50%.
Thinner R-197	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%.

Safety

Fire

Most organic solvents are

hazard; hence empty containers of volatile solvents should be stored open and upside down.

Both

are able to ignite its vapors.

In addition some solvents, such as methanol, can burn with a very hot flame which can be nearly invisible under some lighting conditions.[20]^[21] This can delay or prevent the timely recognition of a dangerous fire, until flames spread to other materials.

Explosive peroxide formation

, but all ethers are considered to be potential peroxide sources.

The heteroatom (

] The carbon-centered 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 dark conditions.

Unless a

. 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 airtight container, away from light, because both light and air can encourage peroxide formation.[22]

A number of tests can be used to detect the presence of a peroxide in an ether; one is to use a combination of

.

Peroxides may be removed by washing with acidic iron(II) sulfate, filtering through

Health effects

General health hazards associated with solvent exposure include toxicity to the nervous system, reproductive damage, liver and kidney damage, respiratory impairment, cancer, hearing loss,^[25][26] and dermatitis.^[27]

Acute exposure

Many solvents^[

fracking fluids, can cause hypotension and metabolic acidosis.^[30]

Chronic exposure

Main article: Chronic solvent-induced encephalopathy

Chronic solvent exposures are often caused by the inhalation of solvent vapors, or the ingestion of diluted solvents, repeated over the course of an extended period.

Some solvents can damage internal organs like the liver, the kidneys, the nervous system, or the brain. The cumulative brain effects of long-term or repeated exposure to some solvents is called chronic solvent-induced encephalopathy (CSE).^[31]

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.^[32] Ethanol has 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.

Some organic solvents are known or suspected to be cataractogenic. A mixture of

aliphatic hydrocarbons, alcohols, esters, ketones, and terpenes were found to greatly increase the risk of developing cataracts in the lens of the eye.^[33]

Environmental contamination

A major pathway of induced health effects arises from spills or leaks of solvents, especially chlorinated 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.^[34] Vapor intrusion can occur from sites with extensive subsurface solvent contamination.^[35]

See also

Wikimedia Commons has media related to Solvents.

• ASTDR
• Construction | Refurbishment | Renovation
• Free energy of solvation
• IARC
• 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 reaction
• List of water-miscible solvents
• Lyoluminescence
• Occupational health
• Partition coefficient (log P) is a measure of differential solubility of a compound in two solvents
• Pollution
• Solvation
• Solvent systems exist outside the realm of ordinary organic solvents: Supercritical fluids, ionic liquids and deep eutectic solvents
• Superfund
• Volatile Organic Compound
• Water model
• Water pollution

References

1. ^ "What's the Difference Between Acetone and Non-acetone Nail Polish Remover?". 3 November 2009.
2. ISBN 978-3527306732
   .
3. ISBN 978-0-13-026607-1
   .
4. ^ Lowery and Richardson, pp. 181–183
5. doi:10.6028/jres.056.001
   .
6. ^ ^{a b} Lowery and Richardson, p. 177.
7. ^ Kosower, E.M. (1969) "An introduction to Physical Organic Chemistry" Wiley: New York, p. 293
8. doi:10.1016/S0010-8545(00)82045-7
   .
9. ^ Lowery and Richardson, p. 183.
10. ^ ^{a b} Solvent Properties – Boiling Point Archived 14 June 2011 at the Wayback Machine. Xydatasource.com. Retrieved on 26 January 2013.
11. ^ Dielectric Constant Archived 4 July 2010 at the Wayback Machine. Macro.lsu.edu. Retrieved on 26 January 2013.
12. doi:10.1021/acs.oprd.6b00015
    .
13. ^
    ISBN 978-0-9551220-2-6
    .
14. ^
    ISBN 978-0-8493-7248-3
    .
15. ^ Selected solvent properties – Specific Gravity Archived 14 June 2011 at the Wayback Machine. Xydatasource.com. Retrieved on 26 January 2013.
16. ^ "dcpt.ru Solvent 646 Characteristics (ru)".
17. ^ "dcpt.ru Solvent 647 Characteristics (ru)".
18. ^ "dcpt.ru Solvent 648 Characteristics (ru)". Archived from the original on 17 May 2017. Retrieved 18 January 2018.
19. ^ "dcpt.ru Solvent 650 Characteristics (ru)".
20. doi:10.4271/841378. Archived
    from the original on 12 August 2017.
21. ISSN 0010-2202
    .
22. ^ "Peroxides and Ethers | Environmental Health, Safety and Risk Management". www.uaf.edu. Retrieved 25 January 2018.
23. ^ "Handling of Peroxide Forming Chemicals". Retrieved 24 September 2021.
24. PMID 30411016
    .
25. ^ https://www.cdc.gov/niosh/docs/2018-124/pdfs/2018-124.pdf
26. ^ https://pubmed.ncbi.nlm.nih.gov/16938795/
27. ^ "Solvents". Occupational Safety & Health Administration. U.S. Department of Labor. Archived from the original on 15 March 2016.
28. ^ Rood, David (7 November 2007). "National: Recall ordered for toy that turns into drug". www.theage.com.au.
29. S2CID 36652482
    .
30. S2CID 23257894
    .
31. PMID 22560998
    .
32. PMID 1606027
    .
33. S2CID 31344706
    .
34. PMID 26388862
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35. PMID 22142966
    .

Bibliography

• Lowery TH, Richardson KS (1987). Mechanism and Theory in Organic Chemistry (3rd ed.).
  ISBN 978-0-06-364044-3
  .

External links

Look up solvent in Wiktionary, the free dictionary.

• Solvent selection tool ACS Green Chemistry Institute
• "European Solvents Industry Group - ESIG - ESIG European Solvents Industry Group" 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
• EPA – Solvent Contaminated Wipes