GB2023643A

GB2023643A - Lubricating Oil Composition Containing Oximino Compounds

Info

Publication number: GB2023643A
Application number: GB7826361A
Authority: GB
Original assignee: Shell Internationale Research Maatschappij BV
Current assignee: Shell Internationale Research Maatschappij BV
Priority date: 1978-06-05
Filing date: 1978-06-05
Publication date: 1980-01-03

Abstract

Oximino compounds of general formula:- <IMAGE> wherein R is an optionally substituted C1-30 hydrocarbyl group and X is H, C1-30 alkyl or a -CH=N-OH group, are used as additives for lubricating oils to decrease lacquer and sludge formation in internal combustion engines.

Description

SPECIFICATION Lubricating Oil Composition Containing Oximino Compounds This invention relates to a lubricating oil composition containing oximino compounds which decrease lacquer and sludge formation in internal combustion engines such as gasoline engines and diesel engines.

Lacquer formation in engines such as gasoline engines and diesel engines is a very complicated process, of which the mechanism is not quite clear. It is supposed that partly burned fuel in blow-by gases together with some oxidized base oil and even some additives polymerizes in a condensation reaction in which nitrogen (NO,) play an important role. In particular lacquer formation on the valve lifters and cylinders walls appears to be the largest problem.

From British Patent Specification 934,385 it is known to combat lacquer deposits on cylinder and piston walls by adding to the lubricating oil a polymeric compound having a structure constituted by a chain of at least 150 carbon atoms, which chain carries both > C=N-0H groups and oleophilic groups which contain at least 8 carbon atoms, or substituents containing these groups.

It has now been found that this problem can be solved by using simple non-polymeric compounds. Thus according to the present invention there is now provided a lubricating oil composition comprising a major amount of a lubricating oil and a minor amount of an oximino compound with the general formula:~

in which X is hydrogen, an alkyl group containing 1-30 carbon atoms or a

group, wherein y is an integer of 0--30, and R is a hydrocarbyl group or a substituted hydrocarbyl group containing 1-30 carbon atoms.

The lubricating oils to which the compounds according to the invention are added may be of various types. Thus they may be added to mineral lubricating oils of diverse viscosity, including hydrocracked and/or hydrofinished lubricating base oils.

The additives are also suitable incorporated into synthetic oils such as polyolefins, ester oils or polyalkylene oxides as well as into lubricating oils containing fatty oils. Mixtures of these oils can also be used.

Suitable oximino compounds are those in which the substituent R is an alkyl group or an alkaryl group with an alkyl chain of at least 8 carbon atoms, such as an alkylphenol group.

To the aromatic nucleus, e.g. the phenyl group, there may be attached more alkyl groups including lower alkyl groups, and/or e.g. polar groups such as hydroxyl groups. The substituent X is preferably a hydrogen atom, a lower alkyl group such as a methyl group or an additional oximino group.

The amount of the oximino compound is preferably 0.1 to 1 0%w.

Other additives may be present, such as antioxidants, detergents, viscosity index improvers, pour-point depressants and extreme pressure agents.

Preparation Oximino compounds are prepared by converting the corresponding carbonyl compound (aldehyde or ketone) with hydroxylamine.

Accordingly, decanaldoxime was made by the reaction of decanal with a slight molar excess of hydroxyl-amino-hydrochloride in the presence of sodium carbonate. The precipitate from this reaction was isolated and recrystallized from ethanol.

Examples The invention is illustrated by the following examples.

Three oximino compounds according to the invention were treated in the synthetic sludge test (SST) and the air oxydation test(AOTJ Description SST A fuel is partially oxidized in an airstream containing NOx and the exhaust gases are passed through oil at 14000. The sludge which is formed after 16 h is isolated and weighed.

Base oil=mixture of HVI 160 B and HVI 60 (about 1/1 by vol) with a kinematic viscosity Vk(2100F)=8 cSt.

Description of AOT An airstream containing NO2 is blown through oil at 1 6000 and the induction period is determined by measurement of 02 consumption with time.

The three compounds further called A, B and C were:~

The amounts of sludge formed in the SST were: additive 1%w sludge g 2.0 A 0.5 B 1.0 C 0.6 The AOT was carried out with an oil composition containing a commercial additive package, including a basic Ca alkylsalicylate or naphthenate, a succinimide type dispersant and a zinc dialkyldithiophosphate in base oil HVI 160 B.

NO2 Induction Additive (ppmv) Period (h) 100 9.9 A 1%w 100 11.2 - 50 11.9 B 2%w 50 23.5 T=1 600C airstream 15 I/h (Sample size A: 30 g; B: 25 g) Reaction rate K,* Additive (moP1 . I. .1.

1.56 A 18.9 B 28.2 *Reaction AH+NO2 - > products at 1 300C in diphenylether (unreactive towards NO2).

Claims

1. Lubricating oils compositions comprising a major amount of a lubricating oil and a minor amount of an oximino compound with the general formula:~

in which X is hydrogen, an alkyl group containing 1-30 carbon atoms or a

2. Lubricating oil composition according to Claim 1, in which the amount of the oximino compound is from 0.1 to 1 0%w.

3. Composition according to Claim 1, in which R is an alkyl substituted phenyl group and the alkyl group contains at least 8 carbon atoms.

4. Composition according to Claim 3, in which the phenyl group contains a hydroxyl group.

5. Composition according to Claim 1, as hereinbefore described, with special reference to the Examples.