Solid anti-friction devices – materials therefor – lubricant or se – Lubricants or separants for moving solid surfaces and... – Organic -co- compound
Reexamination Certificate
1999-07-21
2001-09-18
Medley, Margaret (Department: 1714)
Solid anti-friction devices, materials therefor, lubricant or se
Lubricants or separants for moving solid surfaces and...
Organic -co- compound
C508S331000, C508S332000
Reexamination Certificate
active
06291408
ABSTRACT:
The present invention relates to new detergent-dispersant additives for lubricating oils of the sulphurised and superalkalised, alkaline earth alkylsalicylate-alkylphenate type having improved properties in terms of foaming, compatibility and dispersion in oils and stability towards hydrolysis, and to a process for the preparation thereof.
It is already known from the U.S. Pat. No. 3,036,971, published on May 29, 1962, to prepare detergent-dispersant additives based on sulphurised alkylphenates of high basicity alkaline earth metals by sulphurisation of an alkylphenol, neutralisation of the sulphurised alkylphenol with an alkaline earth base, then superalkalisation by carbonation of the alkaline earth base dispersed in the sulphurised alkylphenate; this type of product has the disadvantage of being relatively unstable towards hydrolysis, with the formation of a precipitate of crystalline calcium carbonate, particularly if said type of product is highly superalkalised, which leads to risks of blockages in the filters of marine engines.
It is also known from the French patent 1.563.557 published on Apr. 11, 1969 to prepare detergent additives based on sulphurised calcium alkylsalicylates by carboxylation of a potassium alkylphenate, exchange with calcium chloride, then sulphurisation of the calcium alkylsalicylate obtained with sulphur in the presence of lime, a carboxylic acid and an alkylene glycol or alkylether of alkylene glycol; such a process has the disadvantage of requiring an exchange reaction.
Under these circumstances, the applicant described in French patent application 2.625.220 published on Jun. 30, 1989 a process for the preparation of superalkalised detergent-dispersant additives based on alkylphenates and alkylsalicylates, which comprises the following steps:
a) neutralisation of an alkylphenol having C
8
to C
30
alkyl substituents by an alkaline earth base in the presence of a C
1
to C
18
acid and of a solvent forming an azeotrope with the water of reaction at a temperature corresponding to the reflux temperature of the azeotrope;
b) distillation of the solvent;
c) carboxylation using carbon dioxide under pressure to convert the alkylphenate to alkylsalicylate;
d) sulphurisation and superalkalisation by sulphur and an alkaline earth base in the presence of glycol and a third solvent, followed by carbonation;
e) and finally filtration.
However, this process developed by the applicant and the products obtained by said process have several disadvantages.
Firstly, in the neutralisation step, the use of a solvent giving an azeotrope with water is needed to obtain a sufficient degree of conversion of alkylphenol to alkylphenate.
The carboxylation step takes place at elevated pressures generally between 5 and 15.10
5
Pa in order to convert the alkylphenate to alkylsalicylate.
Moreover, the sulphurisation and superalkalisation step is dangerous from an industrial point of view because it gives rise to a sudden release of hydrogen sulphide which could not be controlled.
Finally, the products obtained by this former process have properties of dispersion and compatibility with lubricating oils that are inferior to those of alkylsalicylates having the same alkaline earth metal content and, in particular, exhibited poor stability towards hydrolysis, requiring frequent changes of the filters used in the lubricating circuits of marine engines.
The applicant has now found that he was able to improve substantially the performance of said additives, particularly in the tests relating to foaming, compatibility and dispersion in a new oil and in the tests of stability towards hydrolysis, by preparing them by a process comprising the following steps:
A) Neutralisation of alkylphenols containing at least 35 wt. % and at most 85 wt. % of linear alkylphenol in which the linear alkyl radical contains 12 to 40 and preferably 18 to 30 carbon atoms, in mixture with a maximum of 65 and a minimum of 15 wt. % of branched alkylphenol in which the branched alkyl radical contains 9 to 24 and preferably 12 carbon atoms, using an alkaline earth base, in the presence of at least one carboxylic acid containing from 1 to 4 carbon atoms, said neutralisation operation being carried out at a temperature of at least 215° C., the pressure in the reactor in which the neutralisation reaction is carried out being reduced gradually below atmospheric in order to remove the water of reaction, in the absence of any solvent capable of forming an azeotrope with the latter. The quantities of reagents used correspond to the following molar ratios:
alkaline earth base/total alkylphenol between 0.2 and 0.7 and preferably between 0.3 and 0.5,
total carboxylic acid/total alkylphenol between 0.01 and 0.5 and preferably between 0.03 and 0.15;
B) Carboxylation of the alkylphenate obtained in step A) in order to convert at least 22 mole % and preferably at least 25 mole % of the starting alkylphenols to alkylsalicylate (measured as salicylic acid), by the action of carbon dioxide, at a temperature between 180 and 240° C., preferably between 190 and 220° C., under a pressure which may range from atmospheric pressure to 15×10
5
Pa (15 bars) for a period of one to eight hours, optionally in the presence of a dilution oil (for example, 100 N) added at the beginning or at the end of step A or step B;
C) Sulphurisation and superalkalisation of the mixture of alkylphenate and alkylsalicylate obtained by elemental sulphur in the presence of an alkaline earth base, a monoalcohol having a boiling point higher than 150° C. and preferably higher than 175° C. and optionally at this stage an alkylene glycol or an alkylether of alkylene glycol at a temperature between 145 and 180° C., preferably between 150 and 160° C. The quantities of reagents used correspond to the following molar ratios:
sulphur/total alkylphenol between 0.3 and 1.5, and preferably between 0.8 and 1.0;
total alkaline earth base/total alkylphenol between 1.0 and 3.5 and preferably between 1.4 and 3.0;
total alkaline earth base/monoalcohol having a boiling point higher than 150° C. between 0.3 and 0.5,
then, after the addition of the alkylene glycol or the alkylether thereof, if it has not already been added in a molar ratio of total alkaline earth base/alkylene glycol between 1.0 and 3.0 and preferably between 1.4 and 1.8, carbonation of the medium obtained by carbon dioxide at a temperature of 145 to 180° C. and under a pressure close to atmospheric pressure, the quantity of CO
2
used being between that which can be completely absorbed by the reaction medium and an excess of 30% of this quantity;
D) Removal of the alkylene glycol and the monoalcohol by distillation;
E) Filtration to remove the sediments;
F) And finally degassing in the air at a temperature between 80 and 160° C., preferably between 100 and 140° C. until the classification of the copper strip is 1A in the test according to the standard ASTM D-130 carried out for at least 15 minutes at 150° C. and preferably for 1 hour at 150° C.
According to another aspect, the present invention also relates to a detergent-dispersant additive for lubricating oil of the sulphurised and superalkalised, alkaline earth alkylsalicylate-alkylphenate type, characterised in that
a) the alkyl substituents of said alkylsalicylate-alkylphenate are in a proportion of at least 35 wt. % and at most 85 wt. % of linear alkyl in which the number of carbon atoms is between 12 and 40, preferably between 18 and 30 carbon atoms, with a maximum of 65 wt. % of branched alkyl in which the number of carbon atoms is between 9 and 24 and preferably 12 carbon atoms;
b) the proportion of alkylsalicylate in the alkylsalicylate-alkylphenate mixture is at least 22 mole % and preferably at least 25 mole % and
c) the molar proportion of alkaline earth base with respect to the alkylsalicylate-alkylphenate as a whole is between 1.0 and 3.5.
The additives obtained according to the present invention may have a high basicity, reflected by the BN of said additives and measured according to the standard ASTM-D2896 and which may readily re
Cazin Jacques
Coent Jean-Louis Le
Triconnet Thierry
Willis, Jr. William W.
Chevron Chemical Company LLC
Medley Margaret
Stumpf Walter L.
Toomer Cephia D.
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