RU2192450C1 - Method of preparing addition agent for lubricating oil - Google Patents

Abstract

FIELD: lubricants. SUBSTANCE: addition agent is synthesized by interaction of C₃-C₁₀-aliphatic alcohols with phosphorus pentasulfide with the following neutralization of synthesized dialkyldi-thiophosphoric acids with zinc oxide and purification of addition agent obtained. Stages of interaction and neutralization are carried out in cavitation regimen in mechanical- chemical reactor at the rotor rotation rate providing the value of ratio of amount of collapsing cavitating bubble to working chamber volume = 1.3-15. Method provides decrease of time producing thermally stable addition agent by 2-3-fold and producing addition agent with stable pH value near to neutral one. EFFECT: improved method of producing, simplified method of treatment. 3 ex

Description

 The invention relates to the field of petrochemistry, in particular to a method for producing a multifunctional additive for lubricating oils.

 Salts of dithiophosphoric acid diesters are widely known as oil additives. The most common are zinc dialkyldithiophosphates containing various alkyl radicals and having different thermal stability.

 Various methods are known for producing such additives based on the interaction of pentasulfur phosphorus with alcohols to dialkyldithiophosphoric acids, followed by neutralization with their basic zinc compounds.

 The neutralization reaction in the presence of solvents, for example alcohols, and surfactants, helps to obtain additives with thermal stability (US patent 4215067, 29.07.80).

 There is a method of directly neutralizing dialkyl or diaryldithiophosphoric acids with zinc base by passing the mixture through a stationary mixer. Various promoters — nitric acid, carboxylic acids, or their salts — can be used to accelerate neutralization (US Pat. No. 4,104,291, 08/01/78).

 To prevent the precipitation of the obtained zinc dialkyldithiophosphates in oil, they are mixed with succinimide (US Pat. No. 4,495,075, 01/22/85).

The closest technical solution to the claimed one is a method for producing an additive to lubricating oils by reacting C ₃ -C ₁₀ aliphatic alcohols with five-sulfur phosphorus followed by two-stage neutralization of the obtained dialkyldithiophosphoric acids with zinc oxide, taken in a specific ratio to acids, and purification of the additive (RF patent 2130478, 05/20/99).

 The disadvantage of this method is that to obtain a hydrolytically and thermally stable additives, considerable time is required, and the need to maintain a certain ratio of zinc oxide to acids at each stage can complicate the process in industry.

 The objective of the present invention is to eliminate the disadvantages of the known method.

The problem is solved by the method of obtaining additives for lubricating oils by reacting C ₃ -C ₁₀ aliphatic alcohols with five-sulfur phosphorus, followed by two-stage neutralization of the obtained dialkyldithiophosphoric acids with zinc oxide and purification of the obtained additive, in which the interaction and neutralization stages are carried out in the cavitation mode in a mechanochemical reactor at a speed rotation of the rotor, providing the ratio of the number of collapsing cavitation bubbles to the working volume of the reactor chamber, avnoy 1,3-15.

 The method allows to reduce the time to obtain hydrolytic and thermally stable additives by 2-3 times. In addition, the method makes it possible to simplify the subsequent purification step and to obtain an additive having a stable pH close to neutral.

Example 1
A mixture of 181 g (2.4 mol) of isobutyl alcohol and 104.6 g (0.8 mol) of isooctyl alcohol at 70 ^{° C.} for 45 minutes is circulated together with 188 g (0.84 mol) of pentasulfur phosphorus in nitrogen through mechanochemical reactor with a rotor speed of 500 rpm (the ratio of the number of collapsing cavitation bubbles to the working volume of the reactor chamber is 1.3). After cooling and filtration, a mixture of dialkyldithiophosphoric acids is obtained having an acid number of 208 mg KOH / g.

Then, 59.8 g of zinc oxide are added to 59.1 g of dialkyldithiophosphoric acids at 50 ^{° C.} and circulated through a mechanochemical reactor under the same conditions for 15 minutes. Then the reaction water is removed under vacuum at 70-80 ^o C.

After purification by centrifugation at 70-80 ^{° C.} , an additive having a pH value of 6.6 is obtained. Content,%: zinc - 10.2; phosphorus - 9.8; sulfur - 21.2.

Example 2
To 216.2 g of a mixture of dialkyldithiophosphoric acids obtained under the conditions of Example 1, 36.6 g of zinc oxide are added at 60 ^{° C.} and circulated through a mechanochemical reactor at a rotor speed of 1000 rpm (the ratio of the number of collapsing cavitation bubbles to the working volume of the chamber the reactor is 6.5). Then the reaction water is removed under vacuum at 70-80 ^o C.

After purification by centrifugation at 70-80 ^{° C.} , an additive having a pH value of 6.5 is obtained. Content,%: zinc - 9.8; phosphorus - 9.2; sulfur - 19.1.

Example 3
To a mixture of 140 g of n-butyl and 48.5 g of isopropyl alcohol at 40-50 ^{° C.} add 150 g of five-sulfur phosphorus and mix for 15 minutes in a nitrogen medium through a mechanochemical emulsifying reactor at a rotor speed of 1500 rpm (ratio of quantity collapsing cavitation bubbles to the working volume of the reactor is 15). After cooling and filtration, a mixture of dialkyldithiophosphoric acids is obtained having an acid number of 235 mg KOH / g.

88.2 g of the obtained mixture of acids and 24.7 g of mineral oil I-20A are mixed at 60-65 ^o C with 16.3 g of zinc oxide and circulated through a mechanochemical emulsifying reactor at a rotor speed of 1300 rpm (the ratio of the number of collapsing cavitation bubbles to the working volume of the reactor is 12.6) for 20 minutes The reaction water is distilled off in vacuo at 70 ^° C. After purification by centrifugation at 60-70 ^{° C.} , zinc dialkyldithiophosphate is obtained with a pH of 6.5. Content,%: zinc 11.3; phosphorus 9.2; sulfur 18.9.

 The method according to the invention makes it possible to reduce the time of receipt of the additive by 2-3 times, to simplify the subsequent cleaning of the additive from mechanical impurities and unreacted zinc oxide, which is an important technological characteristic in the preparation of dithiophosphates, and to obtain an additive having a stable pH close to neutral.

Claims (1)

The method of obtaining additives for lubricating oils by the interaction of aliphatic alcohols C ₃ -C ₁₀ with five-sulfur phosphorus, followed by neutralization of the obtained dialkyldithiophosphoric acids with zinc oxide and purification of the obtained additive, characterized in that the stages of interaction and neutralization are carried out in the cavitation mode in a mechanochemical reactor at a rotational speed of the rotor providing a ratio of the number of collapsing cavitation bubbles to the working volume of the reactor chamber, equal to 1.3-15.