150-50-5

Usage

Uses

Used in Agriculture Industry:
MERPHOS was used as a defoliant for cotton crops, facilitating easier machine harvesting by promoting leaf abscission. It was applied at rates of 1.1–2.2 kg active ingredient per acre and was also effective in inducing leaf drop in other plants, such as roses and hydrangeas.
Additionally, MERPHOS was employed as an organophosphate pesticide in the agriculture industry, with the technical product having a 95% purity level. It was available in formulations containing 720 g of active ingredient per liter or as an emulsifiable concentrate with 6 lb per gallon.
Chemical Properties:
MERPHOS is described as an emulsifiable oil and is characterized as a nearly colorless liquid. It is insoluble in water but soluble in a variety of organic solvents.

Reactivity Profile

Organothiophosphates, such as MERPHOS, are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrides. Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides.

Hazard

Cholinesterase inhibitor.

Safety Profile

Poison by intraperitoneal route. Moderately toxic by ingestion and skin contact. A cholinesterase inhibitor. Combustible when exposed to heat or flame. Can react vigorously with oxidzing materials. When heated to decomposition it emits highly toxic fumes of POx and SOx. Used as a defoliant. See also PARATHION.

Environmental Fate

Merphos is adsorbed strongly to soil and oxidized to S,S,S-tributyl phosphorotrithioate (DEF). The Koc estimated for merphos is theoretically 62 000; accordingly, merphos would be immobile in soil. In water, merphos will be oxidized to DEF. The fact that merphos is expected to adsorb strongly to particulate matter in the water column, apparently did not impede its oxidation. In the atmosphere, merphos will exist as an aerosol and be removed by gravitational settling and readily oxidized to DEF. Vapor-phase merphos will react with photochemically produced hydroxyl radicals, with an estimated half-life of 4.9 h.

InChI:InChI=1/C12H27PS3/c1-4-7-10-14-13(15-11-8-5-2)16-12-9-6-3/h4-12H2,1-3H3

Upstream product

• 109-79-5 n-butanethiol 
• 629-45-8 dibutyl disulfide 
• 3553-78-4 n-butylthiotrimethylsilane 
• 52416-06-5 dibutyl diethylphosphoramidodithioite 
• 108-98-5 thiophenol 
• 28896-77-7 dibutyl phosphorochloridodithioite 

Downstream Products

• 629-45-8 dibutyl disulfide 
• 28896-77-7 dibutyl phosphorochloridodithioite 
• 78-48-8 S,S,S-tributylphosphorotrithioate 
• 28519-31-5 4-Methylbenzolthiosulfonsaeure-S-butylester 

Relevant academic research and scientific papers

Diphenyl Diselenide-Catalyzed Synthesis of Triaryl Phosphites and Triaryl Phosphates from White Phosphorus

Industrially important triaryl phosphites, traditionally prepared from PCl3, have been synthesized by a diphenyl diselenide-catalyzed one-step procedure involving white phosphorus and phenols, which provides a halogen- and transition metal-free way to these compounds. Subsequent oxidation of triaryl phosphites produces triaryl phosphates and triaryl thiophosphates. Phosphorotrithioates are also prepared efficiently from aromatic thiols and aliphatic thiols.

Process for producing stable, low odor S,S,S-tributylphosphorothrithiote

The invention is directed to a process for producing a stable, low odor S,S,S-tributylphosphorotrithioate having a level of dibutyl disulfide of 0.3% by weight or less. The process broadly includes the steps of a) reacting S,S,S-tributylphosphorotrithioite with an oxidizing agent to produce a crude S,S,S-tributylphosphorotrithioate, b) treating the crude product with sodium bisulfite to decompose any excess oxidizing agent, c) adding a caustic solution having a caustic concentration of from 25 to 50% by weight directly to the reaction mixture of step b), the addition of said caustic solution being stopped once the total caustic concentration is less than 10% by weight and once the pH is constant, and d) phase separating S,S,S-tributylphosphorotrithioate from the mixture of step c).

Pesticide compositions and method

Toxicant, especially pesticide compositions, having lowered dermal toxicity are provided. The compositions include a lipophilic-pesticide, a nonionic surfactant and a dry inert diluent carrier. Methods for reducing the dermal toxicity of lipophilic toxicants, especially pesticides are provided, as well as methods for controlling insect pests using the disclosed compositions.

Deodorized organothiophosphorous and emulsifiable concentrates thereof

Organothiophosphorous compounds, e.g., Merphos, which contain or develop malodorous mercaptan impurities during storage, are protected against such odor development by the addition of minor amounts (0.1 to 10%) of a ketone, especially in the presence of a catalyst such as cuprous chloride or p-toluene sulfonic acid in a concentration range of 0.01 to 0.1%. Formulated products are also claimed.