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Methylene bisphenyl isocyanate

Synonyms & Trade Names
4,4'-Diphenylmethane diisocyanate, MDI, Methylene di-p-phenylene ester of isocyanic acid, Methylene bis(4-phenyl isocyanate)
CAS No.
101-68-8
RTECS No.
NQ9350000
DOT ID & Guide
Formula
CH₂(C₆H₄NCO)₂
Conversion
1 ppm = 10.24 mg/m3
IDLH
75 mg/m3
See: 101688
Exposure Limits
NIOSH REL
TWA 0.05 mg/m3 (0.005 ppm) C 0.2 mg/m3 (0.020 ppm) [10-minute]
OSHA PEL
C 0.2 mg/m3 (0.02 ppm)
Measurement Methods
NIOSH 5521 , 5522 , 5525;
OSHA 18
See: NMAM or OSHA Methods
Physical Description
White to light-yellow, odorless flakes. [Note: A liquid above 99°F.]
Molecular Weight
250.3
Boiling Point
597°F
Melting Point
99°F
Solubility
0.2%
Vapor Pressure
(77°F): 0.000005 mmHg
Ionization Potential
?
Specific Gravity
1.23 (Solid at 77°F) 1.19 (Liquid at 122°F)
Flash Point
390°F
Upper Exposive Limit
?
Lower Explosive Limit
?
Combustible Solid
Incompatibilities & Reactivities
Strong alkalis, acids, alcohol [Note: Polymerizes at 450°F.]
Exposure Routes
inhalation, ingestion, skin and/or eye contact
Symptoms
irritation eyes, nose, throat; resp sensitization; cough, pulmonary secretions, chest pain, dyspnea (breathing difficulty); asthma
Target Organs
Eyes, respiratory system
Personal Protection/Sanitation
(See protection codes)
Skin:Prevent skin contact
Eyes:Prevent eye contact
Wash skin:When contaminated
Remove:When wet or contaminated
Change:Daily
First Aid
(See procedures)
Eye:Irrigate immediately
Skin:Soap wash immediately
Breathing:Respiratory support
Swallow:Medical attention immediately
Respirator Recommendations

NIOSH

Up to 0.5 mg/m3:
(APF = 10) Any supplied-air respirator*

Up to 1.25 mg/m3:
(APF = 25) Any supplied-air respirator operated in a continuous-flow mode*

Up to 2.5 mg/m3:
(APF = 50) Any self-contained breathing apparatus with a full facepiece
(APF = 50) Any supplied-air respirator with a full facepiece

Up to 75 mg/m3:
(APF = 2000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode

Emergency or planned entry into unknown concentrations or IDLH conditions:
(APF = 10,000) Any self-contained breathing apparatus that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode
(APF = 10,000) Any supplied-air respirator that has a full facepiece and is operated in a pressure-demand or other positive-pressure mode in combination with an auxiliary self-contained positive-pressure breathing apparatus

Escape:
(APF = 50) Any air-purifying, full-facepiece respirator (gas mask) with a chin-style, front- or back-mounted organic vapor canister having an N100, R100, or P100 filter.
Click here for information on selection of N, R, or P filters.
Any appropriate escape-type, self-contained breathing apparatus

Important additional information about respirator selection

See also
INTRODUCTION   ICSC CARD: 0298   MEDICAL TESTS: 0147

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