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Zincdialkyldithiophosphate, Zincdiaryldithiophosphate (ZnDDP)

CAS no 84605-29-8

Synonyms Zincdialkyl(C3-C6)dithiophosphate
Phosphorodithioic acid,
mixed O, O’bis(1,3 dimethylbutyl and 1-methylethyl) esters, zinc salt








CAS no

Zinc O,O-di(C1-14-alkyl) dithiophosphates  68649-42-3
Zinc (mixed O,O-bis(sec-butyl and isooctyl)) dithiophosphates 113706-15-3
Zinc-O,O-bis(branched and linear C3-8-alkyl) dithiophosphates 133628-63-4
Zinc O,O-bis(2-ethylhexyl) dithiophosphate 4259-15-8
Zinc O,O-bis(mixed isobutyl and pentyl) dithiophosphates 68457-79-4
Zinc mixed O,O-bis(1,3-dimethylbutyl and isopropyl) dithiophosphates 84605-29-8
Zinc O,O-diisooctyl dithiophosphate 28629-66-5
Zinc O,O-dibutyl dithiophosphate 6990-43-8
Zinc mixed O,O-bis(2-ethylhexyl and isobutyl and isopropyl) dithiophosphates  85940-28-9
Zinc O,O-bis(dodecylphenyl) dithiophosphate  54261-67-5
Zinc O,O-diisodecyl dithiophosphate  25103-54-2
Zinc O-(6-methylheptyl)-O-(1-methylpropyl) dithiophosphate  93819-94-4
Zinc O-(2-ethylhexyl)-O-(isobutyl) dithiophosphate  26566-95-0
Zinc O,O-diisopropyl dithiophosphate  2929-95-5
Zinc (mixed hexyl and isopropyl) dithiophosphates  68412-58-8
Zinc (mixed O-(2-ethylhexyl) and O-isopropyl) dithiophosphates  68909-93-3
Zinc O,O-dioctyl dithiophosphate 7059-16-7
Zinc O,O-dipentyl dithiophosphate  7282-31-7
Zinc O-(2-methylbutyl)-O-(2-methylpropyl) dithiophosphate  94022-84-1
Zinc O-(3-methylbutyl)-O-(2-methylpropyl) dithiophosphate  94022-85-2

The Products Register lists about 30 different substances/groups of substances of this type.

ZnDDP is usually manufactured by first forming dialkyldithiophosphates by a reaction between phosphorus sulphide (P4S10) and alcohol. These are then neutralised by adding zinc oxide, whereupon ZnDDP is obtained.

Zinc dialkyl- and diaryldithiophosphates are used in many lubricating oils as anti-wear agents. These compounds are multifunctional because they are also anti-corrosive and anti-oxidative. They have been used since the 1930s and today are the dominant anti-wear agent, occurring in virtually every motor oil on the market.

ZnDDP is used in motor oils, hydraulic pumps, gear boxes, transmissions and metal machining. Usually ZnDDP constitutes about 1% of these oils, and it acts by creating a protective layer on metallic surfaces at elevated pressures and temperatures. Anti-wear agents functioning in this way are usually called EP additives, EP being short for “extreme pressure”. The characteristic of substances of this type is that at a certain given pressure and temperature they disintegrate and, with their functional groups (sulphur and/or phosphorus) react with the iron in the metal. 

These inorganic ironsulphides and/or ironphosphides which are formed provide extremely strong layers on the metallic surfaces, added to which, they give a lower coefficient of friction.


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