DD278148A1 - LUBRICANTS WITH IMPROVED AGING STABILITY - Google Patents

Abstract

The invention relates to lubricating oils with improved aging stability, which are particularly suitable for use at medium and higher temperatures. According to the invention, the lubricating oils contain, in addition to known lubricating oil additives, from 0.1 to 1.5% by weight of organic phosphites of defined structures, alone or in admixture. The lubricating oil compositions according to the invention have an excellent aging stability even in the presence of catalytically active metals at medium and high temperatures, without adversely affecting other performance properties.

Description

wherein R _{3 is} hydrogen, C ₁ - to C ₂ 4-alkyl, C ₅ - to Ce-cycloalkyl, C ₁ - to C ₅ -hydroxyalkyl and

η is 1 to 24, and

R ₄ to R ₇ independently of one another are hydrogen, C ₁ - to C ₉ -alkyl, cycloalkyl, aralkyl, alkylaryl

or hydroxyl, in amounts of 0.1 to 1.5 wt .-%.

Field of application of the inventor

The invention relates to lubricating oils having improved aging stability, preferably for use at medium and higher temperatures.

Characteristic of the known state of the art

It is confessed. that lubricating oils based on hydrocarbons, at higher temperatures and / or exposure to oxygen and the presence of water and catalytically active metals, are subject to oxidative decomposition. In particular, metals such as copper and iron, whose catalytic activity is based on a valence change of the ions, reduce the oxidation stability of such compounds and lead to the formation of sludge and other oxidation products.

It also produces such products that promote corrosion on metal surfaces.

To improve the oxidation resistance of hydrocarbons, sterically hindered phenols, aromatic amines, alkylphenol sulfides and zinc dialkyldithiophosphates have already been used.

Due to their low solubility or effectiveness, the known oxidation inhibitors are suitable only to a limited extent for use in lubricating oils. Zinc dialkyldithiophosphates have the particular disadvantage that they tend to decompose at temperatures above 12O ⁰ C and form ashes that contaminate the oil.

Another disadvantage of the known additives is that their preparation is economically very complicated and is partly not sufficiently compatible with other conventional additives.

Object of the invention

The aim of the invention is to produce on the basis of available chemical intermediate or finished products, cost and with little technological effort lubricating oils with improved aging stability.

Explanation of the essence of the invention

The invention has for its object to improve lubricating oils in their resistance to oxidation so that they have an excellent aging stability even in the presence of catalytically active metals at medium and high temperatures.

According to the invention the object is achieved in that a paraffin-based mineral oil or MineralölkomDonenten in lubricating oil quality, which are processed by known process steps, regardless of the technological circuit, such as distillation, hydrorefining, dewaxing, optionally Solventratfination and / or contact bleaching, with organic phosphites of the general formula I. and II.

ο - ρ.

οΛο

P - OR.

in which R 1 and R _2, independently of one another, denote C ₁ - to C ₂₄ -alkyl, phenyl, benzyl, C ₁ - to C ₂ -alkylcycloalkyl, aralkyl, cycloalkyl,

\ Λ

CH ₂ -OPO-CH - (CHP) -O-P-OCH ₀ - / θ ") H ^ H ² V-

OH Rr,

wherein R _{3 is} hydrogen, C 1 - to C ₂₄ -alkyl, C ₅ - to Ca-cycloalkyl, C 1 - to C ₅ -hydroxyalkyl and

η is 1 to 24, and

R ₄ to R ₇ independently of one another are hydrogen, C ₁ - to C ₉ -alkyl, cycloalkyl, aralkyl, alkylaryl or hydroxyl,

be added alone or in admixture in amounts of 0.1 to 1.5 wt .-%, alone or in combination with other conventional additives. Thus, the aging stability of the lubricating oils is effectively improved without adversely affecting the effectiveness of other common additives or other performance properties. The other additives may be antioxidants, corrosion or rust inhibitors, EP additives or pour point depressants, depending on the field of application in the usual concentrations

 The preparation of the finished oils runs according to the usual compounding conditions for lubricating oils.

embodiments

The invention will be explained in more detail below on some embodiments.

example 1

A dewaxing and solvent refined hydroraffinate distillate mixture of kinematic viscosity of 36mm ² / s at 50 ° C, added with 0.1 mass% rust inhibitor based on alkenylsuccinic acid (base oil) becomes 0.5Ma% of an organic phosphite of general formula I. added.

Example 2

A dewaxing and solvent refined hydroraffinate distillate mixture of kinematic viscosity of 36mm ² / s at 50 ° C, added with 0.1 mass% of a rust inhibitor based on an alkenyl succinic acid (base oil) becomes 0.5 mass% of an organic phosphite of the general formula Il admitted.

The resulting products, which are suitable as turbine oils, are tested in an aging test according to TGL 17745 under the following conditions:

Temperature: 120 ° C

Air volume: 5 l / h,

Catalysts: je20ppmCu and Fe naphthenate.

The results of the aging test in comparison to a product of the prior art are listed in the table below. It is 1.0Mj .-% dibutyl-p-cresol (DBPC), which are added to the base oil.

Table: Aging test

Product according to According to product Product of example 1 Example 2 State of the art NZnachN. (MgKOH / g) 1.10 1.10 1.00 NZnachA. (MgKOH / g) 0.88 0.63 1.19 ΔNZ -0.22 -0.47 0.19 Resin to N. (%) 0.35 0.38 0.36 Resin to A. (%) 0.50 1.29 3.80 Δ resin 0.15 0.91 3.44 Centrifuge sludge (%) 0.09 0.07 0.08

N. = naphthenate addition, A. = aging

Claims (1)

Lubricating oils with improved aging stability on the basis of Mineralülf ructions in lubricating oil quality, which may contain other known additives, characterized in that they organic phosphates of general formula I and / or II P - OR ₂ in which R ₁ and R ₂ independently of one another are C ₁ - to C ₂₄ -alkyl, phenyl, benzyl, C ₁ - to C ₁₂ -alkylphenyl, aralkyl, cycloalkyl, V ⁵ s > ; ι " HO - (oxy - CH ₂ - 0 - P - 0 CH - (CH ₂ ) _n - P - 0 CH , ^ n - j - u ^ ₂ H ρ