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US 4,308,214 AGranted
Preparation of dialkyldithiophosphinates
AssigneeCyanamid Canada Inc.
InventorsAllan J. Robertson, Tony Ozog
Life of this patent
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Abstract
Dialkylphosphine is added to a mixture of sulfur and water at 50.degree.-90.degree. C. After approximately 25% of the dialkylphosphine is charged, an alkali, such a sodium hydroxide, is added to neutralize the dialkyldithiophosphinic acid that forms. At this elevated temperature the neutralization reaction proceeds rapidly thereby preventing any alkali from reacting with the sulfur to form sulfides. Dialkyldithiophosphinate yields from this process are on the order of about 95-98%.
Claims10
A process for the preparation of dialkyldithiophosphinate comprising:
- (a) heating a mixture of sulfur and water to about 50.degree. to 90.degree. C.;
- (b) adding to the heated mixture about 10% to 50% of a charge of a dialkylphosphine at a continuous rate;
- and
- (c) adding to the heated mixture containing the charge of dialkylphosphine an alkali at a continuous rate while at the same time adding the remaining 50% to 90% of the charge of dialkylphosphine at a continuous rate
- wherein said continuous rates are such that the alkali acts to neutralize the dialkyldithiophosphinic acid formed during the reaction.
2 more elements
Dependencies are inferred from the claim text.