Product Identification

Product Name

O,O,O',O'-Tetramethyl O,O'-(thiodi-4,1-phenylene) phosphorothioate

Synonyms

Difos
O,O-(Thiodi-4,1-phenylene)phosphorothioic acid, O,O,O,O-tetramethyl ester
O,O,O',O'-Tetramethyl O,O'-thiodi-p-phenylene bis(phosphorothioate)
Phosphorothioic acid, O,O'-(thiodi-4,1-phenylene) o,O,O',O'tetramethyl ester

CAS

3383-96-8

Formula

C16H20O6P2S3

Molecular Weight

466.48

EINECS

222-191-1

RTECS

TF6890000

RTECS Class

Agricultural Chemical and Pesticide; Reproductive Effector; Primary Irritant

Merck

12,9286

Beilstein/Gmelin

1896901

Physical and Chemical Properties

Appearance

White crystalline solid or liquid. Technical grade is a viscous brown liquid.

Solubility in water

insoulble

Melting Point

30.6

Vapor Pressure

9.0e-10

Density

1.32 g/cm3 (20 C)

Usage

Larvicide for mosquitoes, black flies & midges & in other applications.

First Aid Measures

Ingestion

Seek medical assistance.

Inhalation

Move victim to fresh air. Apply artificial respiration if victim is not breathing. Do not use mouth-to-mouth method if victim ingested or inhaled the substance; induce artificial respiration with the aid of a pocket mask equipped with a one-way valve or other proper respiratory medical device. Administer oxygen if breathing is difficult.

Skin

Remove and isolate contaminated clothing and shoes. Immediately flush with running water for at least 20 minutes. For minor skin contact, avoid spreading material on unaffected skin.

Eyes

Immediately flush with running water for at least 20 minutes.

Handling and Storage

Storage

Store in cool, dry, well ventilated, secure area out of reach children and animals.

Handling

All chemicals should be considered hazardous. Avoid direct physical contact. Use appropriate, approved safety equipment. Untrained individuals should not handle this chemical or its container. Handling should occur in a chemical fume hood.

Hazards Identification

Inhalation

Highly toxic, may be fatal if inhaled, swallowed or absorbed through skin. Effects of contact or inhalation may be delayed.

Skin

Profuse sweating is common. Pallor may be noted. Dermal sensitization has been reported.

Eyes

Constriction of the pupil, tearing, and blurred vision are common. Prolonged dialation of the pupils may occur. Salivation commonly occurs.

Ingestion

Nausea, vomiting, abdominal cramps, and diarrhea are common muscarinic effects. Both painless and frank clinical pancreatitis have been reported.

Hazards

Containers may explode when heated.

UN (DOT)

2783

Exposure Controls/Personal Protection

Personal Protection

Wear appropriate protective gloves, clothing and goggles.

Respirators

Wear positive pressure self-contained breathing apparatus (SCBA).

Exposure Effects

Reduced body temperature or elevated body temperature may occur. Low heart rate and abnormally low blood pressure may develop after moderate to severe poisoning. Rapid heart rate, elevated blood pressure, and changes in respiratory rate may also occur. Early giddiness, anxiety headache, and restlessness followed by ataxia, drowsiness, and confusion are common with moderate to severe exposures. Sporadic reports of human birth defects related to organophosphates have not been fully verified.

Exposure limit(s)

TLV: ppm; 10 mg/m3 (ACGIH 1994-1995). OSHA PEL: TWA 15 mg/m3 (total) TWA 5 mg/m3 (resp) NIOSH REL: TWA 10 mg/m3 (total) TWA 5 mg/m3 (resp)

Poison Class

4

Fire Fighting Measures

Flash Point

43-93 (closed cup)

Fire Fighting

Dry chemicals, carbon dioxide for small fires. Water spray, foam for large fires.

Fire Potential

Combustible material: may burn but does not ignite readily.

Accidental Release Measures

Small spills/leaks

Do not touch damaged containers or spilled material unless wearing appropriate protective clothing. Stop leak if you can do it without risk. Cover with plastic sheet to prevent spreading. Absorb or cover with dry earth, sand or other non-combustible material and transfer to containers. DO NOT GET WATER INSIDE CONTAINERS.

Stability and Reactivity

Incompatibilities

Incompatible with alkaline substances.

Stability

Stable indefinitely at room temperature; no observed hydrolysis at pH 8 at room temperature for several wk or at pH 11 at 40 C for several hr. Optimum stability at pH 5-7 stable @ 25 C and in natural fresh and saline waters.

Decomposition

When heated to decomposition it emits toxic phosphorus oxides and sulfur oxides fumes.

Combustion Products

Fire may produce irritating, corrosive and/or toxic gases.

Transport Information

UN Number

2783

Hazard Class

6.1

Packing Group

I; II; III