Solvent



A solvent is a liquid that dissolves a solid, liquid, or gaseous temperature.

Common uses for organic solvents are in dry cleaning (e.g. inorganic solvents (other than water) is typically limited to research chemistry and some technological processes.


Protic and aprotic solvents

Polar solvents can be further subdivided into polar SN2 reaction mechanism.

Polarity, solubility, and miscibility

Solvents and solutes can be broadly classified into polar (hydrophilic) and non-polar (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.

Boiling point

Another important property of solvents is boiling point. This also determines the speed of evaporation. Small amounts of low-boiling solvents like dimethyl sulfoxide need higher temperatures, an air flow, or the application of vacuum for fast evaporation.

Density

Most organic solvents have a lower separatory funnel during chemical syntheses.

Chemical interactions

A solvent will create various weak chemical interactions with the solute to solubilize the solute. The most usual of these interactions are the relatively weak hydrogen bonds (interaction between O-H or N-H hydrogens with adjacent O or N atoms).

Health and Safety

Fire

Most organic solvents are flammable or highly flammable, depending on their volatility. Exceptions are some chlorinated solvents like chloroform. Mixtures of solvent vapors and air can explode. Solvent vapors are heavier than air, they will sink to the bottom and can travel large distances nearly undiluted. Solvent vapors 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 steam pipes, light bulbs, hotplates and recently extinguished bunsen burners are able to ignite its vapours.

Peroxide formation

diisopropyl ether.

The heteroatom (thiocyanate. In extreme cases the peroxides can form crystalline solids within the vessel of the ether.

Unless the sodium hydroxide.

Peroxides may be removed by washing with acidic ferrous sulphate, filtering through oxygen is removed as well.

Health effects

Many solvents can lead to a sudden loss of consciousness if inhaled in large amounts. Solvents like Methanol can cause internal damage to the eyes, including permanent blindness.

It is interesting to note that ethanol has a synergistic effect when taken in combination with many solvents. For instance a combination of benzene and ethanol causes greater nausea/vomiting than either substance alone. Many chemists make a point of not drinking beer/wine/other alcoholic drinks if they know that they have been exposed to an aromatic solvent.[citation needed]

Environmental contamination

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; there may be about 5000 sites worldwide that have major subsurface solvent contamination; this is particularly a health risk if aquifers are affected.

Chronic health effects

Some solvents including chloroform and carcinogenic. Many others can damage internal organs like the liver, the kidneys, or the brain.

General precautions

  • Avoiding being exposed to solvent vapors by working in a fume hood, or with local exhaust ventilation (LEV), or in a well ventilated area
  • Keeping the storage containers tightly closed
  • Never using open flames near flammable solvents, use electrical heating instead
  • Never flush flammable solvents down the drain, read safety data sheets for proper disposal information
  • Avoiding the inhalation of solvent vapors
  • Avoiding contact of the solvent with the skin — many solvents are easily absorbed through the skin. They also tend to dry the skin and may cause sores and wounds.

Properties table of common solvents

The solvents are grouped into non-polar, polar aprotic, and polar protic solvents and ordered by increasing polarity. The polarity is given as the density of nonpolar solvents that are heavier than water is bolded.

Solvent Chemical Formula Boiling point Dielectric constant Density
Non-Polar Solvents
Hexane CH3-CH2-CH2-CH2-CH2-CH3 69 °C 2.0 0.655 g/ml
Benzene C6H6 80 °C 2.3 0.879 g/ml
Toluene C6H5-CH3 111 °C 2.4 0.867 g/ml
Diethyl ether CH3CH2-O-CH2-CH3 35 °C 4.3 0.713 g/ml
Chloroform CHCl3 61 °C 4.8 1.498 g/ml
Ethyl acetate CH3-C(=O)-O-CH2-CH3 77 °C 6.0 0.894 g/ml
Polar Aprotic Solvents
1,4-Dioxane /-CH2-CH2-O-CH2-CH2-O-\ 101 °C 2.3 1.033 g/ml
Tetrahydrofuran (THF) /-CH2-CH2-O-CH2-CH2-\ 66 °C 7.5 0.886 g/ml
Dichloromethane (DCM) CH2Cl2 40 °C 9.1 1.326 g/ml
Acetone CH3-C(=O)-CH3 56 °C 21 0.786 g/ml
Acetonitrile (MeCN) CH3-C≡N 82 °C 37 0.786 g/ml
Dimethylformamide (DMF) H-C(=O)N(CH3)2 153 °C 38 0.944 g/ml
Dimethyl sulfoxide (DMSO) CH3-S(=O)-CH3 189 °C 47 1.092 g/ml
Polar Protic Solvents
Acetic acid CH3-C(=O)OH 118 °C 6.2 1.049 g/ml
n-Butanol CH3-CH2-CH2-CH2-OH 118 °C 18 0.810 g/ml
Isopropanol (IPA) CH3-CH(-OH)-CH3 82 °C 18 0.785 g/ml
n-Propanol CH3-CH2-CH2-OH 97 °C 20 0.803 g/ml
Ethanol CH3-CH2-OH 79 °C 24 0.789 g/ml
Methanol CH3-OH 65 °C 33 0.791 g/ml
Formic acid H-C(=O)OH 100 °C 58 1.21 g/ml
Water H-O-H 100 °C 80 1.000 g/ml

See also

  • 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, deep eutectic solvents
  • Water pollution
  • Solvents are often refluxed with an appropriate desiccant prior to distillation to remove water
  • Occupational health
  This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Solvent". A list of authors is available in Wikipedia.