Everything about Xylene totally explained
The term
xylene refers
to a group of three
benzene derivatives which are used as a
solvent and in the
printing,
rubber, and
leather industries. Xylene is a colorless, sweet-smelling liquid that's very flammable. Like other solvents, xylene is also used as an
inhalant drug for its intoxicating properties.
Chemical properties
The term xylenes refers to a group of 3
benzene derivatives
which encompasses
ortho-,
meta-, and
para-
isomers of
dimethyl benzene. The
o-,
m- and
p- isomers specify to which
carbon atoms (of the main
benzene ring) the two
methyl groups are attached. Counting the
carbon atoms from one of the ring carbons bonded to a methyl group, and counting towards the second ring carbon bonded to a methyl group, the
o- isomer has the
IUPAC name of 1,2-dimethylbenzene, the
m- isomer has the IUPAC name of 1,3-dimethylbenzene, and the
p- isomer has the IUPAC name of 1,4-dimethylbenzene.
The chemical properties differ slightly from isomer to isomer. The melting point is between (
m-xylene) and (
p-xylene). The boiling point for each isomer is around . The density is at around 0.87 kg/L (7.26
lb/U.S. gallon or 8.72 lb/
imp gallon) and thus is less dense than water. Xylene in air can be smelled at 0.08 to 3.7 parts of xylene per million parts of air (ppm) and can begin to be tasted in
water at 0.53 to 1.8 ppm.
Applications
Xylene is used as a
solvent and in the
printing,
rubber, and
leather industries.
p-Xylene is used as a feedstock in the production of
terephthalic acid, which is a
monomer used in the production of
polymers. It is also used as a
cleaning agent for
steel and for
silicon wafers and
chips, a
pesticide (External Link
), a
thinner for paint, and in
paints and
varnishes. It may be substituted for
toluene to thin lacquers where slower drying is desired. It is found in small amounts in
airplane fuel and
gasoline. In animal studies it's often swabbed on the ears of rabbits to facilitate blood flow and collection, although the area must subsequently be cleansed with alcohol to prevent inflammation. Xylene is also used as a fixation agent for animal tissues.
| Xylene Isomers |
| General |
| Common name |
Xylenes |
o-Xylene |
m-Xylene |
p-Xylene |
| Systematic name |
Dimethylbenzenes |
1,2-Dimethylbenzene |
1,3-Dimethylbenzene |
1,4-Dimethylbenzene |
| Other names |
Xylols |
o-Xylol; Orthoxylene |
m-Xylol; Metaxylene |
p-Xylol; Paraxylene |
| Molecular formula |
C8H10 (C6H4C2H6) |
| SMILES |
|
Cc1c(C)cccc1 |
Cc1cc(C)ccc1 |
Cc1ccc(C)cc1 |
| Molar mass |
106.16 g/mol |
| Appearance |
clear, colorless liquid |
| CAS number |
[1330-20-7] |
[95-47-6] |
[108-38-3] |
[106-42-3] |
| Properties |
| Density and phase |
0.864 g/mL, liquid |
0.88 g/mL, liquid |
0.86 g/mL, liquid |
0.86 g/mL, liquid |
| Solubility in water |
practically insoluble |
| Soluble in non-polar solvents such as aromatic hydrocarbons |
| Melting point |
-47.4°C (-53.3°F; 226 K) |
−25°C (-13°F; 248 K) |
−48°C (-54.4°F; 225 K) |
13°C (55.4°F; 286 K) |
| Boiling point |
138.5°C (281.3°F; 412 K) |
144°C (291.2°F; 417 K) |
139°C (282.2°F; 412 K) |
138°C (280.4°F; 411 K) |
| Viscosity |
|
.812 cP at |
.62 cP at |
.34 cP at |
| Hazards |
| MSDS |
Xylenes |
o-Xylene |
m-Xylene |
p-Xylene |
| EU Classification |
Harmful (Xn) |
| NFPA 704 |
|
| Flash point |
|
|
|
|
| R/S statement |
,, :, |
| RTECS number |
|
ZE2450000 |
ZE2275000 |
ZE2625000 |
| Supplementary data page |
| Structure & properties |
n, εr, etc. |
| Thermodynamic data |
Phase behaviour Solid, liquid, gas |
| Spectral data |
UV, IR, NMR, MS |
| Related compounds |
Related aromatic hydrocarbons |
toluene, mesitylene, benzene, ethylbenzene |
| Related compounds |
xylenols - types of phenols |
Except where noted otherwise, data are given for materials in their standard state (at 25°C, 100 kPa) |
Related compounds
Xylenes are a starting material for the production of other chemicals. For instance
chlorination of both methyl groups gives three isomeric xylene dichlorides or 1,2-bis(chloromethyl)benzenes. With oxidizing agents, such as
potassium permanganate (KMnO
4), the methyl group can be oxidized to a
carboxylic acid. By oxidizing both methyl groups,
o-xylene forms
phthalic acid and
p-xylene forms
terephthalic acid.
Health effects
Xylene has an effect on the
brain. High levels from exposure for short periods (14 days or less) or long periods (more than 1 year) can cause headaches, lack of muscle coordination, dizziness, confusion, and changes in one's sense of balance. Exposure of people to high levels of xylene for short periods can also cause irritation of the skin, eyes, nose, and throat; difficulty in breathing; problems with the lungs; delayed reaction time; memory difficulties; stomach discomfort; and possibly changes in the liver and kidneys. It can cause unconsciousness and even death at very high levels (see
inhalants).
Studies of unborn animals indicate that high concentrations of xylene may cause increased numbers of deaths, and delayed growth and development. In many instances, these same concentrations also cause damage to the mothers. It isn't yet known whether xylene harms the unborn fetus if the mother is exposed to low levels of xylene during pregnancy
Besides
occupational exposure, the principal pathway of human contact is via
soil contamination from leaking
underground storage tanks containing petroleum products. Humans who come into contact with the soil or groundwater may become affected. Use of contaminated groundwater as a water supply could lead to adverse health effects.
Further Information
Get more info on 'Xylene'.
|
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