Process for reduced crude sediment in metal salts of hydrocarbyl dithiophosphoric acid
AssigneeChevron Oronite Company LLC
InventorWilliam R. Ruhe, Jr.
Life of this patent
Estimating the term…
Abstract
A process for the manufacture of a low sediment overbased metal dithiophosphate composition is disclosed. The process uses delayed addition of a C1 to C5 mono-carboxylic acid promoter during the neutralization of a primary dialkyl dithiophosphoric acid. The process results in reducing crude sediment whereby the resulting overbased metal dithiophosphate may need not undergo additional filtration steps prior to its intended use.
Claims26
A process for the manufacture of a low sediment overbased metal dialkyl dithiophosphate composition comprising:
- a) reacting a phosphorous sulfide reactant with at least one C3 to C12 primary alcohol to form a dialkyl dithiophosphoric acid;
- b) neutralizing the dialkyl dithiophosphoric acid with a full charge of metal oxide for a sufficient amount of time, to form an intermediate product comprising basic and neutral dialkyl dithiophosphate salts, said intermediate product characterized as having a ratio of basic salt to neutral salt of about 0.075 to about 0.75, wherein said ratio is determined by 31P-NMR analysis;
- c) adding to the intermediate product from 1.5 to 5 weight percent based upon the metal oxide charge, of at least one aliphatic mono-carboxylic acid promoter having 1 to 5 carbon atoms to form a reaction mass;
- and
- d) reacting the reaction mass under suitable temperature and time to form an overbased metal dialkyl dithiophosphate product characterized as having a crude sediment before filtration of 0.01 weight percent or less.
A process for the manufacture of a low sediment overbased zinc dialkyl dithiophosphate composition having a zinc to phosphorous weight ratio of from 1.08 to 1.30 comprising:
- a) forming a slurry of a full charge of zinc oxide in a full charge of a dialkyl dithiophosphoric acid derived from the reaction of phosphorous pentasulfide and at least one C3–C12 primary alcohol;
- b) reacting the slurry in a) under suitable conditions of temperature and time to form a intermediate zinc dialkyl dithiophosphate product comprising basic and neutral salts, said intermediate product characterized as having a ratio of basic salt to neutral salt of from 0.075 to 0.75 as determined by 31P-NMR;
- c) subsequent to step b), feeding from 1.5 to 5 weight percent, based upon the charge of zinc oxide, of a promoter selected from the group consisting of formic acid, acetic acid, propionic acid, butyric acid, iso-butyric acid, pentanoic acid, 2-methyl-butyric acid, 3-methyl-butyric acid, and mixtures thereof to form a reaction mass;
- and
- d) reacting the reaction mass of step c) under suitable temperature and time to form an overbased zinc dialkyl dithiophosphate product characterized as having a sediment of less than 0.01 weight percent and a zinc to phosphorous ratio of from 1.08 to 1.30.
Dependencies are inferred from the claim text.