p-Xylene

  • 1,4-Dimethylbenzene
  • p-Xylol
Formula
C6H4(CH3)2
Structure
Description
Clear, colorless liquid with a characteristic aromatic odor, colorless crystalline solid below 13 deg c.
Uses
Synthesis of terephthalic acid for polyester resins and fibers (dacron, mylar, terylene), pharmaceutical synthesis, insecticides.

Registry Numbers and Inventories.
CAS
106-42-3
EC (EINECS/ELINCS)
203-396-5
EC Index Number
601-040-00-7
EC Class
Flammable; Harmful; Irritant
R 10 20/21 38
RTECS
ZE2625000
RTECS class
Tumorigen; Reproductive Effector
UN (DOT)
1307
Merck
12,10214
Beilstein/Gmelin
1901563
Beilstein Reference
4-05-00-00951
RCRA
U239
Swiss Giftliste 1
G-6790
Canada DSL/NDSL
DSL
US TSCA
Listed
Austrailia AICS
Listed
New Zealand
Listed
Japan ENCS (MITI)
Listed
Korea ECL
Listed

Properties.
Formula
C8H10
Formula mass
106.17
Melting point, °C
13
Boiling point, °C
138.3
Vapor pressure, mmHg
9 (20 C)
Vapor density (air=1)
3.7
Saturation Concentration
1.18% (25 C)
Evaporization number
0.7 (butyl acetate=1)
Odor Threshold Odor threshold 0.05 ppm
Critical temperature
343
Critical pressure
34.64
Density
1.096 g/cm3
Solubility in water
Insoluble
Viscosity
0.34 cp (30 C)
Surface tension
28.48 g/s2 (20 C)
Refractive index
1.4958 (20 C)
Dipole moment
0.07 D
Dielectric constant
2.2 (20 C)
Partition coefficient, pKow
3.15
Heat of fusion
16.8 kJ/mol
Heat of vaporization
35.7 kJ/mol
Heat of combustion
-4560 kJ/mol

Hazards and Protection.
Storage
Keep away from heat and flame. Keep away from sources of ignition. Store in a tightly closed container. Keep from contact with oxidizing materials. Store in a cool, dry, well-ventilated area away from incompatible substances. Keep away from strong acids. Flammables-area.
B2 D2B
Handling
Remove contaminated clothing and wash before reuse. Use with adequate ventilation. Ground and bond containers when transferring material. Use spark-proof tools and explosion proof equipment. Avoid contact with skin and eyes. Empty containers retain product residue, (liquid and/or vapor), and can be dangerous. Keep container tightly closed. Avoid contact with heat, sparks and flame. Avoid ingestion and inhalation. Do not pressurize, cut, weld, braze, solder, drill, grind, or expose empty containers to heat, sparks or open flames.
Protection
Eyes: Wear appropriate protective eyeglasses or chemical safety goggles as described by OSHA's eye and face protection regulations in 29 CFR 1910.133 or European Standard EN166. Skin: Wear appropriate protective gloves to prevent skin exposure. Clothing: Wear appropriate protective clothing to prevent skin exposure.
Respirators
A half-face organic vapor respirator may be worn for up to ten times the exposure limit or the maximum use concentration specified by the appropriate regulatory agency or respirator supplier, whichever is lowest. A full-face piece organic vapor respirator may be worn up to 50 times the exposure limit or the maximum use concentration specified by the appropriate regulatory agency or respirator supplier, whichever is lowest. For emergencies or instances where the exposure levels are not known, use a full-face piece positive-pressure, air-supplied respirator.
Small spills/leaks
Avoid runoff into storm sewers and ditches which lead to waterways. Clean up spills immediately, using the appropriate protective equipment. Wear a self contained breathing apparatus and appropriate Personal protection. (See Exposure Controls, Personal Protection section). Scoop up with a nonsparking tool, then place into a suitable container for disposal. Remove all sources of ignition. Absorb spill using an absorbent, non-combustible material such as earth, sand, or vermiculite. Provide ventilation.
Disposal code
1
Stability
Stable at room temperature in closed containers under normal storage and handling conditions.
Incompatibilities
Strong acids, strong oxidizers.
Decomposition
Carbon monoxide, carbon dioxide, hydrocarbons.

Fire.
Flash Point,°C
27
Autoignition, °C
525
Upper exp. limit, %
7.0
Lower exp. limit, %
1.1
Fire fighting
Wear full protective clothing and NIOSH-approved self-contained breathing apparatus with full facepiece operated in the pressure demand or other positive pressure mode. Fire Extinguishing Media: Dry chemical, foam or carbon dioxide. Water spray may be used to keep fire exposed containers cool, dilute spills to nonflammable mixtures, protect personnel attempting to stop leak and disperse vapors.
Fire potential
Flammable liquid.
Hazards
Vapor is heavier than air and may travel considerable distance to a source of ignition and flash back.May polymerize explosively when involved in a fire. Containers may explode when heated.
Combustion products
Fire will produce irritating, corrosive and/or toxic gases.
Health
2
 
Flammability
3
 
 
Reactivity
0
 

Health.
Exposure limit(s)
OSHA PEL: TWA 100 ppm (435 mg/m3) NIOSH REL: TWA 100 ppm (435 mg/m3) ST 150 ppm (655 mg/m3) NIOSH IDLH: 900 ppm
Poison_Class
4
Exposure effects
Chronic inhalation can cause headache, loss of appetite, nervousness and pale skin. Repeated or prolonged skin contact may cause a skin rash. Repeated exposure of the eyes to high concentrations of vapor may cause reversible eye damage. Repeated exposure can damage bone marrow, causing low blood cell count. May damage the liver and kidneys.
   Ingestion
Aspiration hazard. May cause central nervous system depression, kidney damage, and liver damage. Symptoms may include: headache, excitement, fatigue, nausea, vomiting, stupor, and coma. Causes gastrointestinal irritation with nausea, vomiting and diarrhea. Aspiration of material into the lungs may cause chemical pneumonitis, which may be fatal. Harmful or fatal if swallowed
   Inhalation
Harmful if inhaled. Inhalation of high concentrations may cause central nervous system effects characterized by headache, dizziness, unconsciousness and coma. Prolonged exposure may result in dizziness and general weakness. Irritation may lead to chemical pneumonitis and pulmonary edema. May cause liver and kidney damage. May cause irritation of the respiratory tract with burning pain in the nose and throat, coughing, wheezing, shortness of breath and pulmonary edema. May cause adverse central nervous system effects including headache, convulsions, and possible death. Exposure may give rise to flushing of face, skin rash, an increase in heart and respiration rates, headaches, giddiness, nausea, and vomiting.
   Skin
May be absorbed through the skin in harmful amounts. Exposure may cause irritation characterized by redness, dryness, and inflammation. Prolonged and/or repeated contact may cause defatting of the skin and dermatitis. Skin absorption is slight. Causes blistering of the skin.
   Eyes
Contact with eyes may cause severe irritation, and possible eye burns. Prolonged or repeated exposure may cause conjunctivitis.

First aid
 
   Ingestion
Do NOT induce vomiting. If victim is conscious and alert, give 2-4 cupfuls of milk or water. Never give anything by mouth to an unconscious person. Get medical aid immediately.
   Inhalation
Get medical aid immediately. Remove from exposure to fresh air immediately. If not breathing, give artificial respiration. If breathing is difficult, give oxygen. DO NOT use mouth-to-mouth respiration.
   Skin
Immediately flush skin with plenty of soap and water for at least 15 minutes while removing contaminated clothing and shoes. Get medical aid if irritation develops or persists. Wash clothing before reuse.
   Eyes
Immediately flush eyes with plenty of water for at least 15 minutes, occasionally lifting the upper and lower eyelids. Get medical aid immediately. Do NOT allow victim to rub or keep eyes closed.

Transport.
UN number
1307
Response guide
Hazard class
3
Packing Group
II; III
 
USCG CHRIS Code
XLP
 
32 Aromatic hydrocarbons
HS Code
2902 43 00
 
IMO Pollution Category
C
IMO Hazard code
P