RU2130478C1 - Method of preparing addition agent to lubricating oils - Google Patents

Abstract

FIELD: chemical industry. SUBSTANCE: addition agent is prepared by reacting mixture of C₃-C₁₀-alcohols with phosphorus pentasulfide followed by two-stage neutralization of the resulting mixture of dialkylthiodithiophosphoric acids with zinc oxide when adding zinc oxide in amount of 0.8-2.5 g-mole per g-mole of mixture of dialkylthiodithiophosphoric acids in first stage followed by addition of the remaining dialkyldithiophosphoric acids at total ratio of mixture of acids of 1.74-1.82 g-mole per 1 g-mole of zinc oxide. Method makes it possible to prepare thermally stable addition agent with pH of 5.8-6.2 when using small amount (11-14%) of zinc oxide in excess of stoichiometric amount. EFFECT: more efficient preparation method.

Description

 The invention relates to the field of oil refining and petrochemicals, and in particular to a method for producing additives intended for use in lubricating oils.

 A known method of producing additives for lubricating oils by treating a mixture of primary and secondary low molecular weight alcohols containing less than 4 carbon atoms in alkyl, phosphorus phosphorus, followed by the interaction of the resulting mixture of dialkyldithiophosphoric acids with zinc oxide, by adding a mixture of acids to a suspension of zinc oxide in mineral oil (US patent N 4466895, CL 252-32.7, 1984).

 The disadvantage of this method is that to complete the stage of neutralization and obtain a hydrolytically and thermally stable additives, a long time and a large excess of zinc oxide (up to 60% in excess of stoichiometric amount) are required. Most of the excess zinc oxide remains unreacted, which further complicates the cleaning of the additive.

There is also a known method for producing a lubricating oil additive by reacting dialkyldithiophosphoric acids with zinc oxide having a surface of 4 m ² / g, wherein zinc oxide is first suspended in crude zinc dialkyldithiophosphate and then dialkyldithiophosphoric acid is added. (U.S. Patent No. 5,380,448, CL 252-32.7, 1995).

 The disadvantage of this method is that the involvement of significant amounts of zinc dialkyl dithiophosphate in the process leads to irrational use of the volume of equipment and an increase in energy costs.

The closest technical solution to the claimed is a method of producing additives for lubricating oils by reacting five-sulfur phosphorus with alcohols taken in a molar ratio of 1: 6 - 1:20 at 40-80 ^o C and subsequent neutralization of the resulting mixture of dialkyldithiophosphoric acids with zinc oxide, taken in an amount equivalent to the amount of pentasulfur phosphorus. Unreacted zinc oxide is filtered off.

 (Patent GDR N 205673, CL. C 10 M 1/48, 1982).

 The disadvantage of this method is that the resulting additive does not have the required hydrolytic and thermal stability.

 It is known that stable zinc dialkyldithiophosphate should have a pH of at least 5.65-5.8.

 The objective of the invention is to develop a method for hydrolytically and thermally stable additives to lubricating oils having a pH of at least 5.8.

To solve this problem, a method is proposed for producing additives to lubricating oils by reacting a mixture of C ₃ - C ₁₀ alcohols with five-sulfur phosphorus and subsequent two-stage neutralization of the resulting mixture of dialkyldithiophosphoric acids with zinc oxide by feeding zinc oxide in an amount of 0.8 - 2.5 mol per 1 mol a mixture of dialkyldithiophosphoric acids taken in the first stage, followed by the addition of the remaining dialkyldithiophosphoric acids with a total acid mixture ratio of 1.74 - 1.82 mol per 1 mol of zinc oxide.

 The novelty of the claimed technical solution is the neutralization of a mixture of dialkyldithiophosphoric acids with zinc oxide in two stages, as well as the order of introduction and the ratio of reagents at these stages.

 These differences make it possible to obtain a hydrolytic and thermally stable additive with a pH of 5.8 - 6.2. However, to complete the stage of neutralization does not require a significant excess of zinc oxide. According to the proposed method, the excess of zinc oxide in excess of a stoichiometric amount is 10-14%.

 Below are examples of obtaining additives for the proposed method.

Example 1. To a mixture of 181 g (2.4 mol) of isobutyl alcohol and 104.6 g (0.8 mol) of isooctyl alcohol at 70 ^° C. over a period of 2.8 hours, 188 g (0.84 ml) of pentasulfur are added with stirring. phosphorus. Then the reaction mixture was stirred under a stream of nitrogen at 80 ^° C. for another 1.5 hours. After cooling and filtration, a mixture of dialkyldithiophosphoric acids was obtained having an acid number of 205 mg KOH / g.

To 41 g (0.15 mol) of the stirred mixture of dialkyldithiophosphoric acids in 30 minutes at 50-60 ^o C add 9.8 g (0.12 mol) of zinc oxide. The reaction mixture was stirred for another 15 minutes at 55 ^° C, then 18.1 g (0.066 mol) of dialkyl dithiophosphoric acid mixture was added over 1 hour at 80 ^° C. Stirred for 1 h at 80 ^o C and remove the reaction water in vacuum at 70-80 ^o C. In the first and second stages, 1.8 mol of a mixture of dialkyldithiophosphoric acids per 1 mol of zinc oxide were taken.

After purification by centrifugation at 70-80 ^° C., an additive having a pH of 5.8 is obtained. Found: Zn = 10.9%, P = 10.0%.

Example 2. To 82.1 g (0.3 mol) of a stirred mixture of dialkyldithiophosphoric acids obtained under the conditions of Example 1, 36.6 g (0.45 mol) of zinc oxide was added over 30 minutes at 50-60 ^° C. The reaction mixture was stirred for 15 minutes at 55 ^° C and then 134.1 g (0.49 mol) of dialkyldithiophosphoric acid mixture was added over 1 hour at 80 ^° C. Stirred for 1 h at 80 ^o C and remove the reaction water in vacuum at 70-80 ^o C. In the first and second stages, 1.75 mol of a mixture of dialkyldithiophosphoric acids per 1 mol of zinc oxide were taken.

After purification by centrifugation at 70-80 ^o C receive an additive with a pH of 6.1. Found: Zn = 11.2%; P = 10.0%.

Example 3. To a mixture of 140 g (1.9 mol) of n-butanol and 48.5 g (0.8 mol) of isopropyl alcohol at 40-50 ^° C. over 30 minutes, 150 g (0.68 mol) of pentasulfur are added with stirring. phosphorus. The mixture is stirred for 1 hour at 60 ^° C. After cooling and filtration, a mixture of dialkyldithiophosphoric acids is obtained having an acid number of 229 mg KOH / g.

To 49 g (0.2 mol) of the stirred mixture of dialkyldithiophosphoric acids and 24.7 g of mineral oil I-20A in 30 minutes at 60-65 ^o C add 16.3 g (0.2 mol) of zinc oxide. The mixture was stirred for 20 minutes at 60 ^° C. Then, 39.2 g (0.16 mol) of a mixture of dialkyldithiophosphoric acids were added to the stirred reaction mixture at 60 ^° C. over 1 hour. Stirred for another 1 h at 65 ^o C. The reaction water was distilled off in vacuo at 70 ^o C. In the first and second stages 1.8 mol of dialkyldithiophosphoric acids were taken per 1 mol of zinc oxide. After purification by centrifugation at 60-70 ^° C., zinc dialkyldithiophosphate, pH 6.2, is obtained. Found: Zn - 9.9%; P = 9.0%.

Claims (1)

A method of obtaining an additive to lubricating oils by reacting a mixture of C ₃ - C ₁₀ alcohols with five-sulfur phosphorus and then neutralizing the resulting mixture of dialkyldithiophosphoric acids with zinc oxide, characterized in that the neutralization is carried out in two stages with a supply of zinc oxide in an amount of 0.8 - 2.5 mol per 1 mol of a mixture of dialkyldithiophosphoric acids taken in the first stage, followed by the addition of the remaining dialkyldithiophosphoric acids with a total acid mixture ratio of 1.74 - 1.82 mol per 1 mol of zinc oxide.