EP0273588B2

EP0273588B2 - Sulphurised alkaline earth metal hydrocarbyl phenates, their production and use thereof

Info

Publication number: EP0273588B2
Application number: EP87310461A
Authority: EP
Inventors: Charles Cane; John Crawford; Sean Patrick O'connor
Original assignee: Lubrizol Adibis Holdings UK Ltd
Current assignee: Lubrizol Adibis Holdings UK Ltd
Priority date: 1986-11-29
Filing date: 1987-11-26
Publication date: 2001-03-28
Anticipated expiration: 2007-11-26
Also published as: ZA878939B; JPH0631383B2; DE3781118T2; JPH01501400A; NO176147C; MX169106B; EP0271262B2; JPH0631384B2; DE3781118T3; FI93654C; FI883502A; NO883348D0; FI883502A0; CA1305696C; AU608792B2; DK419788D0; IN169547B; DE3781126T3; BR8707550A; EP0273588B1

Abstract

An additive concentrate suitable for incorporation into a finished lubricating oil composition, the additive concentrate comprising: (a) a lubricating oil, (b) a lubricating oil soluble sulphurised alkaline earth metal hydrocarbyl phenate modified by incorporation of from greater than 2 to 35% by weight based on the weight of the composition of either (i) at least one carboxylic acid having the formula:- R - @@ - COOH (I) wherein R is a C10 to C24 alkyl or alkenyl group and R<1> is either hydrogen, as C1 to C4 alkyl group or a -CH2-COOH group, or an anhydride, acid chloride or ester thereof or (ii) a di- or polycarboxylic acid containing from 36 to 100 carbon atoms or an anhydride, acid chloride or ester thereof, the composition having a TBN greater than 300.

Description

The present invention relates in general to the production of sulphurised alkaline earth metal hydrocarbyl phenate additive concentrates and to their use as lubricating oil additives. In particular the present invention relates to the production of sulphurised alkaline earth metal hydrocarbyl phenate-containing additive concentrates having a high total base number (TBN) and an acceptable viscosity from sulphurised alkaline earth metal hydrocarbyl phenates having lower TBNs.
In the internal combustion engine, by-products from the combustion chamber often blow by the piston and admix with the lubricating oil. Many of these by-products form acidic materials within the lubricating oil. This is particularly marked in diesel engines operating on low-grade fuels of high sulphur content wherein corrosive acids are produced by combustion. The acids thereby incorporated in the lubricating oil can include sulphur acids produced by oxidation of sulphur, hydrohalic acids derived from halogen lead scavengers in the fuel and nitrogen acids produced by the oxidation of atmospheric nitrogen within the combustion chamber. Such acids cause deposition of sludge and corrosion of the bearings and engine parts leading to rapid wear and early breakdown of the engine.
One class of compounds generally employed to neutralise the acidic materials and disperse sludge within the lubricating oil are the sulphurised metal alkyl phenates, wherein the metal is an alkaline earth metal such as calcium, magnesium or barium. Both "normal" and "overbased" sulphurised alkaline earth metal alkyl phenates have been employed. The term "overbased" is used to describe those sulphurised alkaline earth metal alkyl phenates in which the ratio of the number of equivalents of the alkaline earth metal moiety to the number of equivalents of the phenol moiety is greater than one, and is usually greater than 1.2 and may be as high as 4.5 or greater. In contrast, the equivalent ratio of alkaline earth metal moiety to phenol moiety in "normal" alkaline earth metal alkyl phenates is one. Thus, the "overbased" material contains greater than 20% in excess of the alkaline earth metal present in the corresponding "normal" material. For this reason "overbased" sulphurised alkaline earth metal alkyl phenates have a greater capability for neutralising acidic matter than do the corresponding "normal" alkaline earth metal alkyl phenates.
The prior art teaches many methods for preparing both "normal" and "overbased" sulphurised metal alkyl phenates. One such method for preparing "overbased" sulphurised alkyl phenates generally referred to as the "single lime addition" process comprises reacting an alkyl phenol, in the presence of lubricating oil, sulphur, a hydroxylic compound and excess alkaline earth metal hydroxide (above the stoichiometric proportion required to neutralise the alkyl phenol), to form an intermediate product, followed by carbonation, a heading distillation (to remove unreacted hydroxylic compound) and filtration. The production of intermediate product is accompanied by a marked increase in viscosity while the subsequent carbonation reduces the viscosity to a relatively low level. The increase in viscosity accompanying the formation of the intermediate product is undesirable because the reaction mixture becomes difficult to agitate to the detriment of subsequent reactions. Whilst this increase in viscosity may be controlled to an acceptable level by incorporation of less alkaline earth metal hydroxide in the reaction, the overbased alkyl phenate product necessarily possesses a reduced neutralisation capacity. In order to achieve a high neutralisation capacity product and at the same time control the viscosity of the intermediate product within acceptable limits the alkaline earth metal hydroxide may be added in two, (generally referred to as the "double lime addition" process) or three separate reaction steps, with sequential carbonation steps. However, this method involves relatively long batch times. Another alternative is to use viscosity depressants, such as tridecanol, 2-ethylhexanol, or similar boiling range hydroxylic solvent, in the production of the intermediate product but such an expedient increases the raw material cost of the process. The highest total base number (TBN), as measured in mg KOH/g, consistent with an acceptable viscosity, generally achievable by prior art processes is about 300, though generally prior art TBNs are in the range from 200-300. It would clearly be a desirable objective to produce sulphurised alkaline earth metal alkyl phenate compositions having a high TBN that is a TBN greater than 300, and preferably greater than 350. It would also be a desirable objective to produce such materials from sulphurised alkaline earth metal alkyl phenates having a lower TBN. To date it has not been found possible to achieve products of such high TBN because the use of larger concentrations of alkaline earth metal base leads to highly viscous products which, rather than being 'thinned' by subsequent carbonation attemps using excess carbon dioxide, are rendered insoluble. We have achieved these objectives and thereby achieved compositions having a TBN in excess of 300 and in some cases greater than 350 whilst retaining an acceptable viscosity, that is a viscosity of less than 1000 cSt, and avoiding insolubility by incorporating into a reaction mixture containing a sulphurised alkaline earth metal alkyl phenate at least one carboxylic acid or acid derivative thereof having at least 10 carbon atoms in the molecule.
The use of carboxylic acids in the production of sulphurised alkaline earth metal alkyl phenates is not new, see for example US-A-4049560 and EP-A-0094814.
US-A-4049560 describes the production of an overbased magnesium detergent by a process in which carbon dioxide is introduced into a reaction mixture which comprises:
(a) 15-40 wt % of a sulphurised phenol or thiophenol containing one or more hydrocarbyl substituents, or a phenol or thiophenol containing one or more hydrocarbyl substituents, or said phenol or thiophenol containing one or more hydrocarbyl substituents together with sulphur,
(b) 5-15 wt % of an organic sulphonic acid, an organic sulphonate or an organic sulphate,
(c) 5-15 wt % of a glycol, a C₁ to C₅ monohydric alkanol or C₂ to C₄ alkoxy alkanol,
(d) 2-15 wt % of a magnesium hydroxide or active magnesium oxide,
(e) at least 0.1 wt % of a C₁ to C₁₈ carboxylic acid, and
(f) at least 10% by weight of a diluent oil (including any present in components (a) and (b).
The amount of carboxylic acid (component (e)) is preferably in the range 0.5 to 2.0% by weight. The product prepared by this reaction is said to have a TBN of about 200 to 250, e.g. about 225.
EP-A-0094814 discloses an additive concentrate for incorporation in a lubricating oil composition comprising lubricating oil, and from 10 to 90 wt % of an overbased alkaline earth metal hydrocarbyl sulphurised phenate which has been treated, either during or subsequent to the overbasing process, with from 0.1 to 10, preferably 2 to 6, wt % (based on the weight of additive concentrate) of an acid of the formula:
(wherein R is a C₁₀ to C₂₄ unbranched alkyl or alkenyl group, and R¹ is hydrogen, a C₁ to C₄ alkyl group or a -CH₂-COOH group) or an anhydride or a salt thereof. The object of the invention of EP-A-0094814 is to overcome problems encountered with many additive concentrates containing overbased additives, namely lack of stability giving rise to sedimentation and foaming problems. The problem of EP-A-0094814 is not that of producing phenates having a TBN of greater than 300 and indeed the phenates produced by the process of the invention, although overcoming the problems of stability and foaming, have TBN values of less than 300.
Our European Application Publication No. 0095322 discloses a process for the production of either an alkaline earth metal alkyl phenate or a sulphurised alkaline earth metal alkyl phenate which process comprises reacting at elevated temperature, in the presence or absence of sulphur, an alkyl phenol with an alkaline earth metal base in the presence as solvent of either an alkylene glycol alkyl ether or a polyalkylene glycol alkyl ether of formula: R(OR¹)_xOR² wherein R is a C₁ to C₆ alkyl group, R¹ is alkylene, R² is hydrogen or C₁ to C₆ alkyl and x is an integer in the range 1 to 6 and as catalyst an inorganic halide. It is said to be preferred to add a small amount, suitably up to 2% w/w of an acid, a suitable acid being stearic acid. The addition of stearic acid to the reactants can, it is said, enhance the ability of alkylphenates to minimise emulsion formation in water.
It can be concluded that the prior art in which carboxylic acids are employed does not address the problem of producing overbased sulphurised alkaline earth metal alkyl phenates having a TBN of greater than 300 and an acceptable viscosity.
Our copending European Application No. 0271262 claiming the same priority date as the present application provides an additive concentrate suitable for incorporation into a finished lubricating oil composition, the additive concentrate comprising:
(a) a lubricating oil,
(b) a lubricating oil soluble sulphurised or non-sulphurised alkaline earth metal hydrocarbyl phenate modified by incorporation of from greater than 2 to less than 40% by weight based on the weight of the composition of either (i) at least one carboxylic acid having the formula:-
wherein R is a C₁₀ to C₂₄ alkyl or alkenyl group and R¹ is either hydrogen, a C₁ to C₄ alkyl group or a -CH₂-COOH group, or an anhydride, acid chloride or ester thereof or (ii) a di-or polycarboxylic acid containing from 36 to 100 carbon atoms or an anhydride, acid chloride or ester thereof, the composition having a TBN greater than 300.
In one aspect the present invention provides a process for the production of an additive concentrate suitable for incorporation into a finished lubricating oil composition, the additive concentrate comprising:
(a) a lubricating oil,
(b) a lubricating oil soluble sulphurised alkaline earth metal hydrocarbyl phenate modified by incorporation of from greater than 10 to 35% by weight based on the weight of the concentrate of at least one carboxylic acid having the formula:-
wherein R is a C₁₀ to C₂₄ straight chain alkyl group and R¹ is hydrogen, or an anhydride or ester thereof or, the concentrate having a TBN greater than 300 and a viscosity at 100° of less than 1000 mm².s^-1 (cSt), which process comprises reacting at elevated temperature:
(A) a sulphurised alkaline earth metal hydrocarbyl phenate having a TBN less than that of the final additive concentrate,
(B) an alkaline earth metal base, either added in whole to the initial reactants, or in part to the initial reactants and the remainder in one or more portions at a subsequent stage or stages in the process,
(C) either a polyhydric alcohol having from 2 to 4 carbon atoms, a di- or tri- (C₂ to C₄) glycol, an alkylene glycol alkyl ether or a polyalkylene glycol alkyl ether,
(D) a lubricating oil,
(E) carbon dioxide added subsequent to the, or each, addition of component (B), and
(F) sufficient to provide from greater than 10 to 35% by weight based on the weight of the concentrate of at least one carboxylic acid having the formula:-
wherein R is a C₁₀ to C₂₄ straight chain alkyl and R¹ is hydrogen, or an anhydride or ester thereof or the weight ratios of components (A) to (F) being such as to produce a concentrate having a TBN greater than 300.
The process of the invention is advantageous because it affords a method for up-grading low TEN products of the prior art or off-specification products into high TBN products having an acceptable viscosity. Moreover, because hydrogen sulphide is not evolved during operation of the process of the invention, in contrast to processes for producing sulphurised alkaline eanh meral alkyl phenates involving the reaction of an alkyl phenol and sulphur, by the more conventional routes, the hydrogen sulphide disposal problem is avoided, thereby allowing manufacture in environmentally sansitive locations and the use of less sophisticated plant.
Component (a) of the concentrate is a lubricating oil. The lubricating oil may suitably be either an animal oil, a vegetable oil or a mineral oil. Suitably the lubricating oil may be a petroleum-derived lubricating oil, such as a naphthenic base, paraffin base or mixed base oil. Solvent neutral oils are particularly suitable. Alternatively, the lubricating oil may be a synthetic lubricating oil. Suitable synthetic lubricating oils include synthetic ester lubricating oils, which oils include diesters such as di-octyl adipate, di-octyl sebacate and tridecyladipate, or polymeric hydrocarbon lubricating oils, for example liquid polyisobutenes and poly-alpha olefins. The lubricating oil may suitably comprise from 10 to 90%, preferably from 10 to 70%, by weight of the concentrate.
Component (b) is a lubricating oil soluble sulphurised alkaline earth metal hydrocarbyl phenate modified by incorporation of from greater than 10 to 35% by weight based on the weight of the concentrate of the carboxylic acid.
Suitably the alkaline earth metal may be strontium, calcium, magnesium or barium, preferably calcium, barium or magnesium, more preferably calcium.
The hydrocarbyl phenate moiety of the sulphurised alkaline earth metal hydrocarbyl phenate is preferably derived from at least one alkyl phenol. The alkyl groups of the alkyl phenol may be branched or unbranched. Suitable alkyl groups contain from 4 to 50, preferably from 9 to 28 carton atoms. A particularly suitable alkyl phenol is the C₁₂-alkyl phenol obtained by alkylating phenol with propylene tetramer.
The sulphurised alkaline earth metal hydrocarbyl phenate is modified by incorporation of at least one carboxylic acid having the formula (I) or an acid anhydride or ester thereof. Preferably R in the formula (I) is an unbranched alkyl group. Preferred acids of formula (I) are those wherein R is a C₁₀ to C₂₄, more preferably C₁₈ to C₂₄ straight chain alkyl groups and R¹ is hydrogen. Examples of suitable saturated carboxylic acids of formula (I) include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid and lignoceric acid.
Mixtures of acids may also be employed, for example rape top fatty acids. Particularly suitable mixtures of acids are those commercial grades containing a range of acids, including both saturated and unsaturated acids. Such mixtures may be obtained synthetically or may be derived from natural products, for example cotton oil, ground nut oil, coconut oil, linseed oil, palm kernel oil, olive oil, com oil, palm oil, castor oil, soyabean oil, sunflower oil, herring oil, sardine oil and tallow. Sulphurised adds and acid mixtures may also be employed. Instead of, or in addition to, the carboxylic acid there may be used the acid anhydride or the ester derivatives of the acid, preferably the acid anhydride. It is preferred however to use a carboxylic acid or mixture of carboxylic acids. A preferred carboxylic acid of formula (I) is stearic acid.
The carboxylic acid(s) having the formula (I), the acid anhydride or ester thereof is incorporated in an amount from greater than 10% to 35%, preferably from 12 to 20%, for example about 16% by weight based on the weight of the concentrate. An advantage of incorporating greater than 10% of the carboxylic acid or derivative thereof is generally relatively lower concentrate viscosity.
Suitably the alkaline earth metal may be present in the composition in an amount in the range from 10 to 20% by weight based on the weight of the concentrate.
Suitably sulphur may be present in the concentrate in an amount in the range from 1 to 6, preferably from 1.5 to 3% by weight based on the weight of the concentrate.
Suitably carbon dioxide may be present in the concentrate in an amount in the range from 5 to 20. preferably from 9 to 15% by weight based on the weight of the concentrate.
Preferably the TBN of the concentrate is greater than 350, more preferably greater than 400.
Suitably the concentrate may have a viscosity measured at 100°C of less than 1000 cSt. preferably less than 750 cSt, more preferably less than 500 cSt.
Component (A) of the reaction mixture is a sulphurised alkaline earth metal hydrocarbyl phenate having a TBN lower than that of the final product i.e. generally less than 300. Any suiphurised alkaline earth metal hydrocarbyl phenate may be employed. The sulphurised alkaline earth metal hydrocarbyl phenate may be carbonated or non-carbonated. The alkaline earth metal moiety and the hydrocarbyl phenate moiety of the sulphurised alkaline earth metal hydrocarbyl phenate may suitably be as hereinbefore described. Methods for preparing sulphurised alkaline earth metal hydrocarbyl pnenates are weil known in the art. Alternatively, the precursors of a sulphurised alkaline earth metal hydrocarbyl phenate in the form of a non-sulphurisad alkaline earth metal hydrocarbyl phenate may be employed.
The alkaline earth metal base (component B) may suitably be an alkaline earth metal oxide or hydroxide, preferably the hydroxide. Calcium hydroxide may be added for example in the form of slaked lime. Preferred alkaline earth metals are calcium, magnesium and barium and more preferred is calcium. The alkaline earth metal base must be added in an amount relative to component (A) sufficient to produce a product having a TBN in excess of 300, preferably in excess of 350. This amount will depend on a number of factors including the nature of the sulphurised alkaline earth metal hydrocarbyl phenate. Typically the weight ratio of component (B) to component (A) may suitably be in the range from 0.1 to 50, preferably from 0.2 to 5. The alkaline earth metal base (B) may be added in whole to the initial reactants, or in part to the initial reactants and the remainder in one or more portions at a subsequent stage or stages in the process. Preferably component (B) is added in a single addition to the initial reactants.
Component (C) is either a polyhydric alcohol having from 2 to 4 carbon atoms, a di-or tri-(C₂ to C₄) glycol, an alkylene glycol alkyl ether or a polyalkylene glycol alkyl ether. The polyhydric alcohol may suitably be either a dihydric alcohol, for example ethylene glycol or propylene giycol, or a trihydric alcohol, for example glycerol. The di-or tri-(C₂ to C₄) glycol may suitably be either diethylene glycol or triethylene glycol. The alkylene glycol alkyl ether or polyalkylene glycol alkyl ether may suitably be of the formula:- R (OR¹)_xOR² wherein R is a C₁ to C₆ alkyl group, R¹ is an alkylene group, R² is hydrogen or C₁ to C₆ alkyl and x is an integer in the range from 1 to 6. Suitable solvents having the formula (II) include the monomethyl or dimethyl ethers of ethylene glycol, diethylene glycol, triethylene glycol or tetraethylene glycol. A particularly suitable solvent is methyl digol (CH₃OCH₂CH₂OCH₂CH₂OH). Mixtures of glycols and glycol ethers of formula (II) may also be employed. Using a glycol or glycol ether of formula (II) as solvent it is preferred to use in combination therewith an inorganic halide, for example ammonium chloride, and a lower, i.e. C₁ to C₄, carboxylic acid, for example acetic acid. Preferably the component (C) is either ethylene glycol or methyl digol, the latter in combination with ammonium chloride and acetic acid.
Component (D) is a lubricating oil as hereinbefore described with reference to the concentrate composition.
Component (E) is carbon dioxide, which may be added in the form of a gas or solid, preferably in the form of a gas. In gaseous form it may suitably be blown through the reaction mixture. We have found that generally the amount of carbon dioxide incorporated increases with increasing concentrations of component (F). The carbon dioxide is preferably added subsequent to a single addition of component (B) at the conclusion of the reaction between component (A), (B), (C), (D) and (F).
Component (F) is a carboxylic acid of formula (I), or an acid anhydride or ester thereof as hereinbefore described with reference to the concentrate composition. The amount of the aforesaid required to provide from greater than 10 to 35% by weight based on the weight of the concentrate will be to a first approximation the amount defined in the concentrate. In calculating this amount allowance should be made for loss of water from carboxylic acids, for example.
The reaction may be performed in the presence of a diluent. Suitable diluents are liquids having a volatility consistent with operation of the process, i.e. having a volatility such that they are readily strippable from the reaction mixture at the conclusion of the reaction. Examples of suitable diluents include 2-ethyl hexanol, iso-octanol, iso-heptanol and tri-decanol.
Further sulphur, that is sulphur additional to that already present by way of component (A), may be added to the reaction mixture. An advantage of adding further sulphur is that it increases the amount of sulphur in the concentrate, which may be desirable for certain applications. On the other hand sulphur addition leads to the evolution of hydrogen sulphide, thereby to some extent detracting from the advantage of the invention as hereinbefore mentioned.
Preferably the reaction is carried out in the presence of a further component which is a catalyst for the reaction. As catalyst there may be used an inorganic halide which may suitably be either a hydrogen halide. an ammonium halide or a metal halide. Suitably the metal moiety of the metal halide may be inc. aluminium or an alkaline earth metal, preferably calcium. Of the halides, the chloride is preferred. Suitable catalysts include hydrogen chloride, calcium chloride, ammonium chloride, aluminium chloride and zinc chloride, preferably calcium cnloride. Suitably the amount of catalyst employed may be up to 2.0% wt/wt.
Suitably the reaction of components (A) - (F) and also the carbonation reaction may be carried out at elevated temperatures in the range from 120 to 200, preferably from about 130 to 165°C, though the actual temperature chosen for the reaction of components (A) - (F) and the carbonation may differ if desired. The pressure may be atmospheric, subatmospheric or superatmospheric.
The concentrate may be recovered by conventional means, for example by distillative stripping of component (C) and diluent (if any).
Finally, it is preferred to filter the concentrate so-obtained. Generally, the process of the invention will produce a concentrate having an acceptable viscosity, that is a viscosity of less than 1000 cSt at 100°C and can produce concentrates having a viscosity less than 750 or 500 cSt at 100°C. Moreover, the concentrates generally have desirable viscosity index properties. Such viscometric properties are advantageous because they facilitate processing (including filtration) of the concentrate. However, it is also possible to produce concentrates having a higher viscosity than 1000 cSt at 100°C, generally at higher TBN levels. Filtration of such concentrates presents a problem, which may be overcome by adding a diluent prior to to filtration and stripping the diluent off after filtration. Alternatively, or in addition, the concentrate may be diluted with lubricating oil and still retain a TBN in excess of 300, particularly if the TBN of the concentrate as produced is high, for example above 400.
In a further aspect the present invention provides an additive concentrate suitable for incorporation into a finished lubricating oil which concentrate is obtainable by reacting at elevated temperature (A) a sulphurised alkaline earth metal hydrocarbyl phenate having a TBN less than that of the final additive concentrate, (B) an alkaline earth metal base either added in whole to the initial reactants, or in part to the initial reactants and the remainder in one or more portions at a subsequent stage or stages in the process, (C) either a polyhydric alcohol having from 2 to 4 carbon atoms, a di-or tri-(C₂ to C₄) glycol, an alkylene glycol alkyl ether or a polyalkylene glycol alkyl ether, (D) a lubricating oil, (E) carbon dioxide added subsequent to the, or each, addition of component (B), and (F) sufficient to provide from greater than 10 to 35% by weight based on the weight of the concentrate of a carboxylic acid having the formula (I) or an acid anhydride or ester thereof or an acid anhydride or ester thereof, the weight ratio of components (A) to (F) being such as to produce a concentrate having a TBN greater than 300 and a viscosity at 100°C of less than 1000 mm².s^-1 (cSt).
A finished lubricating oil composition comprises a lubricating oil and sufficient of the additive concentrate produced in the manner as hereinbefore described to provide a TBN in the range from 0.5 to 120.
Preferably the finished lubricating oil composition contains sufficient of the concentrate to provide a TBN in the range from 0.5 to 100.
The amount of the concentrate present in the finished lubricating oil will depend on the nature of the final use. Thus, for marine lubricating oils the amount of concentrate composition present may suitably be sufficient to provide a TBN in the range from 9 to 100 and for automobile engine lubricating oils the amount may suitably be sufficient to provide a TBN in the range from 4 to 20.
The finished lubricating oil may also contain effective amounts of one or more other types of conventional lubricating oil additives, for example viscosity index improvers, anti-wear agents, antioxidants. dispersants, rust inhibitors, pour-point depressants, or the like, which may be incorporated into the finished lubricating oil composition either directly or through the intermediacy of the concentrate.
In addition to their use as additives for incorporation into lubricating oil compositions, the concentrates of the present invention may also find application as fuels additives.
The invention will now be further illustrated by reference to the following Examples.
In all the Examples the term "TBN" is used. The TBN is the Total Base Number in mg KOh/g as measured by the method of ASTM D2896.
In all the Examples, except otherwise expressly stated, a commercially available sulphurised calcium alkyl phenate derived from a C₁₂-alkyl phenol was employed. The phenate is supplied as a solution in lubricating oil, which forms from 36-40% w/w of the composition. The composition has a TBN of 250 and a composition as follows:- calcium (9.25% w/w), sulphur (3.25% w/w) and carbon dioxide (4.6% w/w). Where the "Charge" for any Example includes lubricating oil. this is additional to that already present in the phenate composition.
The viscosity was measured by the method of ASTM D445.

Example 1

Up-grading of Sulphurised Calcium Alkyl Phenate

Charge	Lubricating oil	(57 g)
	Sulphurised calcium alkyl phenate	(206 g)
	Lime	(49 g)
	Stearic acid	(70 g)
	Calcium chloride	(4 g)
	2-ethyl hexanol	(112 g)

The charge was heated to 145-165° C/700 mm Hg whilst adding 36 g ethylene glycol. It was then maintained for one hour at 165° C/700 mg Hg. Carbon dioxide (50 g) was added at 165 ° C over 1 hour. The product was cooled to 125° C/700 mm Hg. Lime (33 g) was added. The temperature was raised to 165° C/700 mm Hg and held at this temperature for one hour. Carbon dioxide (25 g) was added at 165° C over one hour. The product was then stripped at 200° C/10 mm Hg. Finally the product was filtered. It was observed that the filtration rate was very fast. 437 g product and 167 g distillate were obtained.

The product was analysed for calcium, sulphur and carbon dioxide. Its TBN, BPHVI50 and Viscosity at 100° C were determined. The BPHVI50 determination is a solubility test. Results of the test are expressed on the scale 1 (highly soluble; pass), 2 (borderline) and 3 (fail).

Results
Calcium =	13.9% w/w (corresponding to 96% retention in the product of the calcium charged.
Sulphur =	1.5% w/w (corresponding to 100% retention in the product of the sulphur charged).
Carbon Dioxide =	12.3% w/w (corresponding to 62% retention in the product of the CO₂ charged).
TBN =	395
V₁₀₀ =	228 cSt
BPHVI50 =	1A
Stearic acid =	16% w/w

This Example demonstrates that a low TBN product can be converted to a high TBN product having an acceptable viscosity by the process of the invention.

Example 2

Charge	Sulphurised Calcium alkyl phenate	230 g
	Lubricating oil	26 g
	Calcium chloride	3 g

Method

(a) The charge was heated to 100° C/700 mm Hg. Stearic acid (63 g) was added and the mixture stirred for 15 minutes,
(b) 2-Ethyl hexanol (190 g) was added at 100 - 110° C/700 mm Hg,
(c) Lime (66 g) was added at 110° C/700 mm Hg,
(d) The mixture was heated to 165° C/700 mm Hg and ethylene glycol (32 g) was added quickly (one minute),
The mixture was held for 5 minutes at 165° C/700 mm Hg,
(f) Carbon dioxide (66 g) was then added at 165° C/1 bar,
(g) The solvent was recovered at 200° C/10 mm Hg, and
(h) The stripped product was filtered.

Product Weights

Crude Product 398 g

Distillate 236 g

Product Composition After Filtration

The filtration rate was fast.

Calcium 14.1% w/w

Sulphur 2.0% w/w

CO₂ 12.9% w/w

TBN 399

V₁₀₀ 825 cSt

Stearic acid 15.8% w/w

Example 3

Charge:: As for Example 2.

Method

As for Example 2 except that the temperature was 145°C instead of 165 °C in steps (d), (e) and (f).

Product Weights

Crude Product 402 g

Distillate 239 g

Product Composition After Filtration

Calcium	13.9% w/w
Sulphur	1.9% w/w
CO₂	13.9% w/w
TBN	392
V₁₀₀	206 cSt
Stearic acid	15.7% w/w

Example 4

Charge: As for Example 2

Method

As for Example 2 except that the temperature was 130 ° C instead of 165 °C in steps (d), (e) and (f).

Products Weights

Crude Product 377 g

Distillate 236 g

Product Composition After Filtration

Calcium	13.7% w/w
Sulphur	2.1% w/w
CO₂	13.2% w/w
TEN	380
V₁₀	99 cSt
Stearic acid	16.7 % w/w

Example 5

Charge:: As for Example 3 except that calcium chloride was omitted.

Method

As for Example 3.

Product Weights

Crude Product 388 g

Distillate 239 g

Product Composition After Filtration

Calcium	11.9% w/w
Sulphur	2.1% w/w
CO₂	9.0% w/w
TBN	331
V₁₀₀	98 cSt
V₄₀	1490 cSt
VI	148
Stearic acid	16.2% w/w

The filtration step (h) was very difficult.
This Example, as compared with Example 3 demonstrates the desirability of using a catalyst in the process of the invention. In the absence of catalyst, although a lower V₁₀₀ was obtained, this was achieved at the expense of reduced incorporation of calcium and carbon dioxide, and moreover filtration was difficult.

Example 6 (not according to the invention)

Charge	Sulphurised calcium alkyl phenate	253 g
	Lubricating oil (100 SN)	26 g
	Calcium chloride	4 g
	2-Ethyl hexanol	190 g
	Stearic acid	40 g

Method

(a) The charge was heated to 120° C/700 mm Hg and lime (36 g) was then added,
(b) The mixture was heated to 145 - 165° C whilst adding ethylene glycol (32 g),
(c) The mixture was held for one hour at 165° C/700 mm Hg,
(d) Carbon dioxide (44 g) was added at 165° C/1 bar,
(e) The mixture was cooled to 120° C and lime (25 g) was added,
(f) The mixture was held at 165° C/700 mm Hg for one hour,
(g) Carbon dioxide (22 g) was added at 165° C/1 bar,
(h) The solvent was stripped off at 200° C/10 mm Hg, and
(i) The product was filtered. The filtration rate was fast.

Product Weights

Crude Product 401 g

Distillate 239 g

Product Composition After Filtration

Calcium	14.3% w/w
Sulphur	2.1% w/w
CO₂	11.3% w/w
TBN	405
V₁₀₀	1483 cSt
Stearic acid	10% w/w

This Example demonstrates that it is possible to produce a high TBN concentrate, though the viscosity is relatively high, by incorporating 10% w/w stearic acid.

Example 7

Charge:: As for Example 6 except that the phenate was increased from 250 g to 268 g and the stearic acid was increased from 40 g to 51 g.

Method:

As for Example 6.

Products Weights

Crude Product 396 g

Distillate 234 g

Product Composition After Filtration

Calcium	14.5% w/w
Sulphur	2.2% w/w
CO₂	13.1% w/w
TBN	399
V₁₀₀	706 cSt
Stearic acid	12.9% w/w

This Example demonstrates that a high TBN concentrate having a lower viscosity as compared with Example 6 can be produced at a stearic acid content of 12.9% w/w based on the weight of the concentrate.

Example 8

Charge	Sulphurised calcium alkyl phenate	230 g
	Lubricating oil (SN 100)	0 g
	Calcium chloride	3 g

Method

(a) The charge was heated to 100° C, stearic acid (99 g) was then added and the mixture was stirred for 15 minutes,
(b) 2-Ethyl hexanol (190 g) was added at 100 - 110° C,
(c) Lime (66 g) was added at 110° C/2" Hg vacuum,
(d) The mixture was heated to 145 ° C/10" Hg and ethylene glycol (32 g) was added over 20 minutes,
(e) The mixture was held for 5 minutes at 145° C/10" Hg,
(f) Carbon dioxide (66 g) was added at 145° C,
(g) The product was stripped at 200° C/30" Hg, and
(h) The product was filtered. The filtration rate was slow.

Product Weights

Crude Product 398 g

Distillate 209 g

Product Composition After Filtration

Calcium	11.95% w/w
Sulphur	1.65% w/w
CO₂	11.6% w/w
TBN	349
V₁₀₀	100 cSt
V₄₀	974 cSt
Stearic acid	24.9% w/w

This Example demonstrates that it is possible to produce a high TBN concentrate having a low viscosity at a stearic acid content of 24.9% w/w.

Comparison Test 1

Charge:: As for Example 3.

Method

As for Example 3 except that the addition of ethylene glycol in step (d) was omitted.

Product Weights

Crude Product 382 g

Distillate 200 g

Product Composition After Filtration

Calcium	8.4% w/w
Sulphur	2.3% w/w
CO₂	4.4% w/w
TBN	239
V₁₀₀	41 cSt

The filtration rate in step (h) was slow.
This is not an example according to the present invention and is included for the purpose of
demonstrating that the presence of a component (C) is essential to the performance of the process of the invention.

Example 9

Charge: As for Example 3.

Method

As for Example 3 except that the ethylene glycol addition in step (d) was reduced from 32 g to 16 g.

Product Weights

Crude Product 399 g

Distillate 225 g

Product Composition After Filtration

Calcium	13.7% w/w
Sulphur	2.0% w/w
CO₂	13.5% w/w
TBN	395
V₁₀₀	182 cSt
Stearic acid	15.8% w/w

The filtration rate in step (h) was slow.
This Example demonstrates that the addition of ethylene glycol can be reduced by 50% as compared with Example 3.

Example 10

Charge	Sulphurised calcium alkylphenate	230 g
	Lubricating oil (100 SN)	26 g
	Ammonium chloride	4 g
	Acetic acid	2 g

Method

As for Example 3 except that in step (b) instead of 2-ethyl hexanol (190 g) there was added methyl diglycol (130 g) and in step (d) the addition of ethylene glycol was omitted.

Product Weights

Crude Product 390 g

Distillate 166 g

Product Composition After Filtration

Calcium	14.1% w/w
Sulphur	2.0% w/w
CO₂	14.2% w/w
TBN	398
V₁₀₀	210 cSt
V₄₀	3821 cSt
VI	170

The filtration rate in step (h) was rapid.
This Example demonstrates that methyl diglycol is effective as component (C).

Example 11

Charge:: As for Example 3.

Method

As for Example 3 except that in step (d) the pressure was 270 mm Hg.

Product Weight

Crude Product 402 g

Distillate 238 g

Product Composition After Filtration

Calcium	14.0% w/w
Sulphur	1.9% w/w
CO₂	14.4% w/w
TBN	392
V₁₀₀	288 cSt
Stearic acid	15.7% w/w
Stearic acid	16.2% w/w

Example 12

Charge: As for Example 3.

Method

As for Example 3 except that instead of 190 g 2-ethyl hexanol there was used 40 g.

Product Weights

Crude Product 399 g

Distillate 90 g

Product Composition After Filtration

Calcium	13.9% w/w
Sulphur	1.9% w/w
CO₂	12.1% w/w
TBN	408
V₁₀₀	387 cSt
V₄₀	7980 cSt
VI	193
Stearic acid	15.8% w/w

Example 13

Charge	Sulphurised calcium alkyl phenate	230 g
	Stearic acid	63 g
	Calcium chloride	4 g
	C₁₈ linear alpha-olefin	26 g
	2-ethyl hexanol	90 g

Method

(a) The mixture was heated to 145 - 165° C/700 mm Hg whilst adding ethylene glycol (32 g),
(b) The mixture was held for 30 minutes at 165° C/700 mm Hg,
(c) CO₂ (38 g) was added at 165° C/1 bar,
(d) The mixture was cooled to 120° C and 2-ethyl hexanol (100 g) added,
(e) Lime (66 g) was added,
(f) The mixture was held at 165° C/700 mm Hg for 5 minutes,
(g) Carbon dioxide (66 g) was added,
(h) The solvent was recovered by stripping at 200° C/10 mm Hg,
(i) The product was filtered.

Product Weights

Crude Product 385 g

Distillate 256 g

Product Composition After Filtration

Calcium	14.8% w/w
Sulphur	1.9% w/w
CO₂	13.4% w/w
TBN	424
V₁₀₀	583 cSt
V₄₀	13,080 cSt
VI	209
Stearic acid	16.4% w/w

The filtration rate in step (i) was rapid.
This Example demonstrates that a lubricating oil can be replaced by a long carbon chain alpha-olefin (in this case C₁₈).

Example 14

Charge	Sulphurised calcium alkyl phenate (250 TBN) derived from a mixture of C₁₂/C₂₂/C₂₄ alkyl phenols	233.5 g
	Lubricating oil (SN 100)	26 g
	Calcium chloride	3 g

Method

(a) The mixture was heated to 100° C, stearic acid (63 g) was added and the mixture was stirred for 15 minutes,
(b) 2-Ethyl hexanol (194 g) was added at 100 - 110° C,
(c) Lime (66 g) was added at 110° C/2" Hg vacuum,
(d) The mixture was heated to 145° C/10" Hg and ethylene glycol (32 g) added over 20 minutes,
(e) The mixture was held for 5 minutes at 145° C/10" Hg,
(f) Carbon dioxide (66 g) was added,
(g) The product was stripped at 200° C/30" Hg,
(h) The product was filtered.

Product Weights

Crude Product 385 g

Distillate 250 g

Product Composition After Filtration

Calcium	14.0% w/w
Sulphur	1.84% w/w
CO₂	12.9% w/w
TBN	401
V₁₀₀	381 cSt
V₄₀	8385 cSt
VI	186
Stearic acid	16.4 % w/w

This Example demonstrates that sulphurised calcium alkyl phenates derived from a mixture of C₁₂/C₂₂/C₂₄ alkyl phenols can be upgraded.

Example 15

Charge	Sulphurised calcium alkyl phenate	181 g
	Lubricating oil (SN 100)	50 g
	Calcium chloride	4 g
	Rape Top Fatty Acid	62 g
	2-Ethyl hexanol	190 g

Method

(a) The mixture was heated to 120° C,
(b) Lime (43 g) was added at 120° C/2" Hg vacuum,
(c) Ethylene glycol (32 g) was added at 145 - 165° C/2" Hg,
(d) The mixture was held at 165° C/2" Hg for 1 hour,
(e) Carbon dioxide (44 g) was added,
(f) The mixture was cooled to 130° C and lime (29 g) was added at 130 °C/2" Hg,
(g) The mixture was held at 165° C/2" Hg for 1 hour,
(h) Lime (22 g) was added at 165° C,
(i) The product was stripped at 200° C/30" Hg,
(j) The product was filtered.

Product Weights

Crude Product 382 g

Distillate 230 g

Product Composition After Filtration

Calcium	14.0% w/w
Sulphur	1.8% w/w
CO₂	12.3% w/w
TBN	374
V₁₀₀	176 cSt
V₄₀	2826 cSt
VI	172
Carboxylic acid content	16.2 % w/w

This Example demonstrates that Rape Top Fatty Acid can be used in the process of the invention.

Example 16

Charge	Sulphurised calcium alkyl phenate	230 g
	Lubricating oil (SN 100)	26 g
	Calcium chloride	3 g

Method

As for Example 2 except that in step (a) instead of stearic acid (63 g) there was used Tall Oil Fatty Acid (63 g).

Product Weights

Crude Product 380 g

Distillate 223 g

Product Composition After Filtration

Calcium	14.0% w/w
Sulphur	2.09% w/w
CO₂	9.7% w/w
TBN	380
V₁₀₀	263 cSt
Carboxylic acid content	16.6 % w/w based on the weight of product.

This Example demonstrates that Tall Oil Fatty Acid can be used in the process of the invention.

Example 17

Charge:: As for Example 16.

Method

As for Example 16 except that instead of Tall Oil Fatty Acid (63 g) there was used a mixture of 52 g polyisobutene succinic anhydride (PIBSA) in SN 100 lubricating oil (TBN = 60 mg KOH/g) and stearic acid (47 g).

Product Weights

Crude Product 390 g

Distillate 219 g

Product Composition After Filtration

Calcium	13.1% w/w
Sulphur	1.8% w/w
CO₂	12.5% w/w
TBN	360
V₁₀₀	416 cSt
V₄₀	12,690 cSt
VI	164
Carboxylic acid content	12.1 % w/w ) based on the
Anhydride content	7.2 % w/w ) weight of product

This Example demonstrates that the carboxylic acid can be replaced in part by PIBSA in the process of the invention.

Example 18

Charge:: As for Example 16.

Method

As for Example 16 except that instead of Tall Oil Fatty Acid (63 g) there was used behenic acid (63 g).

Product Weights

Crude Product 402 g

Distillate 247 g

Product Composition After Filtration

Calcium	12.4% w/w
Sulphur	1.9% w/w
CO₂	11.4% w/w
TBN	354
V₁₀₀	141 cSt
Behenic acid	15.7 % w/w

This Example demonstrates that behenic acid can be used as the carboxylic acid in the process of the invention.

Example 19

Charge:: As for Example 15 except that instead of Rape Top Fatty Acid (62 g) there was used palmitic acid (56.2 g).

Method

As for Example 15 except that steps (f), (g) and (h) were omitted.

Product Weights

Crude Product 312 g

Distillate 222 g

Product Composition After Filtration

Calcium	11.7% w/w
Sulphur	1.9% w/w
CO₂	8.2% w/w
TBN	332
V₁₀₀	70 cSt
V₄₀	831 cSt
VI	156
Palmitic acid	18.0 % w/w

This Example demonstrates that palmitic acid can be used in the process of the invention.

Example 20

Charge:: As for Example 15.

Method

As for Example 15 except that steps (f), (g) and (h) were omitted.

Product Weights

Crude Product 334 g

Distillate 234 g

Product Composition After Filtration

Calcium	11.8% w/w
Sulphur	1.8% w/w
CO₂	10.9% w/w
TBN	321
V₁₀₀	168 cSt
V₄₀	1009 cSt
VI	286
Palmitic acid	18.6 % w/w based on the weight of product.

Comparison Test 2

Method

(a) The mixture was heated to 100° C and 2-ethyl hexanol (190 g) was added,
(b) Acetic acid (14 g) was added,
(c) The mixture became thick and heterogeneous and assumed a green colouration. Stirring was ineffective. The reaction was discontinued.
This Test is not an example according to the present invention and is included only for the purpose of demonstrating that lower carboxylic acids, in this case acetic acid, can not be used in the process of the invention.

Example 21

Charge:: As for Example 16 except that instead of the commercially available sulphurised calcium alkyl phenate there was used an uncarbonated commercially available sulphurised calcium C₁₂-alkyl phenate (145 TBN).

Method

As for Example 16 except that in step (c) the amount of lime was increased from 66 g to 83 g and in step (f) the amount of carbon dioxide was increased from 66 g to 83 g.

Product Weights

Crude Product 421 g

Distillate 246 g

Product Composition After Filtration

Calcium	13.7% w/w
Sulphur	1.9% w/w
CO₂	10.3% w/w
TBN	383
V₁₀₀	137 cSt
V₄₀	2119 cSt
VI	163
Carboxylic acid	15.0% w/w

This Example demonstrates that an uncarbonated sulphurised calcium alkyl phenate of low initial TBN can be used in the process of the invention.

Example 22

Charge:	A carbonated sulphurised calcium alkyl phenate (150 TBN)	253 g
	Stearic acid	40 g
	2-Ethyl hexanol	90 g
	Calcium chloride	4 g

Method

(a) The mixture was heated from 145 to 165° C/700 mm Hg whilst adding ethylene glycol (32 g),
(b) The mixture was held at 165° C/700 mm Hg for 30 minutes,
(c) Carbon dioxide (38 g) was added at 165° C/1 bar,
(d) The mixture was cooled to 120° C and there was added 2-ethyl hexanol (100 g) and lime (76 g),
(e) The mixture was held for 60 minutes at 165° C/700 mm Hg,
(f) Carbon dioxide (82 g) was added at 165° C/1 bar,
(g) Solvent was recovered at 200° C/10 mm Hg, and
(h) The product was filtered.

Product Weights

Product Weight 390 g

Product Composition After Filtration

Calcium	14.4% w/w
Sulphur	2.3% w/w
CO₂	11.6% w/w
TBN	402
V₁₀₀	674 cSt
Stearic acid	10.3% w/w

This Example demonstrates that a low (150) TBN sulphurised calcium alkyl phenate can be upgraded to a high TBN product.

Example 23

Charge:: As for Example 14 except that instead of the sulphurised calcium alkyl phenate derived from a mixture of alkyl phenols there was used the commercially available sulphurised calcium alkyl phenate derived from a C₁₂-alkyl phenol (250 TBN).

Method

As for Example 14 except that in step (b) instead of 2-ethyl hexanol (194 g) there was used iso-heptanol (190 g) and in step (d) the ethylene glycol was added quickly (within 1 minute).

Product Weights

Crude Product 402 g

Distillate 239 g

Product Composition After Filtration

Calcium	13.9% w/w
Sulphur	1.9% w/w
CO₂	12.0% w/w
TBN	391
V₁₀₀	313 cSt
V₄₀	6700 cSt
VI	177
Stearic acid	15.7% w/w

The filtration rate was rapid.
This Example demonstrates that iso-heptanol may be used as solvent in the process of the invention.

Claims

A process for the production of an additive concentrate suitable for incorporation into a finished lubricating oil composition, the additive concentrate comprising:

(a) a lubricating oil,

(b) a lubricating oil soluble sulphurised alkaline earth metal hydrocarbyl phenate modified by incorporation of from greater than 10 to 35% by weight based on the weight of the concentrate of at least one carboxylic acid having the formula:-
wherein R is a C₁₀ to C₂₄ straight chain alkyl group and R¹ is hydrogen, or an anhydride or ester thereof the concentrate having a TBN greater than 300 and a viscosity at 100° C of less than 1000 mm².s^-1 (cSt), which process comprises reacting at elevated temperature:

(A) a sulphurised alkaline earth metal hydrocarbyl phenate having a TBN less than that of the final additive concentrate,

(B) an alkaline earth metal base, either added in whole to the initial reactants, or in part to the initial reactants and the remainder in one or more portions at a subsequent stage or stages in the process,

(C) either a polyhydric alcohol having from 2 to 4 carbon atoms, a di- or tri- (C₂ to C₄) glycol, an alkylene glycol alkyl ether or a polyalkylene glycol alkyl ether,

(D) a lubricating oil,

(E) carbon dioxide added subsequent to the, or each, addition of component (B), and

(F) sufficient to provide from greater than 10 to 35% by weight based on the weight of the concentrate of at least one carboxylic acid having the formula:-
wherein R is a C₁₀ to C₂₄ straight chain alkyl and R¹ is hydrogen, or an anhydride or ester thereof, the weight ratios of components (A) to (F) being such as to produce a concentrate having a TBN greater than 300.
A process according to claim 1 wherein the lubricating oil comprises from 10 to 90% by weight of the concentrate.
A process according to either claim 1 or claim 2 wherein the alkaline earth metal of the lubricating oil soluble sulphurised alkaline earth metal hydrocarbyl phenate is calcium, magnesium or barium.
A process according to claim 3 wherein the alkaline earth metal is calcium.
A process according to any one of the preceding claims wherein the hydrocarbyl phenate moiety of the oil soluble sulphurised alkaline earth metal hydrocarbyl phenate is derived from at least one alkyl phenol, the alkyl group or groups of the alkyl phenol or phenols containing from 9 to 28, carbon atoms.
A process according to claim 5 wherein the hydrocarbyl phenate moiety is derived from a C₁₂-alkyl phenol obtained by alkylating phenol with propylene tetramer.
A process according to any one of claims 1 to 6 wherein there is incorporated a mixture of carboxylic acids of formula (I), which mixture is a commercial grade containing a range of acids, including both saturated and unsaturated acids.
A process according to any one of claims 1 to 6 wherein there is incorporated stearic acid.
A process according to any one of the preceding claims wherein the carboxylic acid, anhydride or ester thereof is incorporated into component (b) in an amount in the range from 12 to 20% by weight based on the weight of the concentrate.
A process according to any one of the preceding claims wherein the TBN of the concentrate is greater than 350.
A process according to claim 10 wherein the TBN of the concentrate is greater than 400.
A process according to any one of the preceding claims wherein the viscosity of the concentrate at 100° C is less than 750 cSt.
A process according to claim 12 wherein the viscosity of the concentrate at 100° C is less than 500 mm².s^-1 (cSt).
A process according to any one of the preceding claims wherein component (B) is lime.
A process according to any one of the preceding claims wherein the weight ratio of component (B) to component (A) is in the range from 0.2 to 5.
A process according to any one of the preceding claims wherein component (C) is ethylene glycol.
A process according to any one of claims 1 to 15 wherein component (C) is methyl digol.
A process according to any one of the preceding claims wherein the carbon dioxide (component E) is added subsequent to a single addition of component (B) at the conclusion of the reaction between components (A) to (D) and (F).
A process according to any one of the preceding claims wherein a diluent is present.
A process according to any one of the preceding claims wherein sulphur additional to that already present by way of component (A) is added to the reaction mixture.
A process according to any one of the preceding claims wherein the reaction is carried out in the presence of a catalyst.
A process according to claim 21 wherein the catalyst is an inorganic halide.
A process according to claim 22 wherein the catalyst is calcium chloride.
An additive concentrate suitable for incorporation into a finished lubricating oil which concentrate is obtainable by reacting at elevated temperature (A) a sulphurised alkaline earth metal hydrocarbyl phenate having a TBN less than that of the final additive concentrate, (B) an alkaline earth metal base either added in whole to the initial reactants, or in part to the initial reactants and the remainder in one or more portions at a subsequent stage or stages in the process, (C) either a polyhydric alcohol having from 2 to 4 carbon atoms, a di-or tri-(C₂ to C₄) glycol, an alkylene glycol alkyl ether or a polyalkylene glycol alkyl ether, (D) a lubricating oil, (E) carbon dioxide added subsequent to the, or each, addition of component (B), and (F) sufficient to provide from greater than 10 to 35% by weight based on the weight of the concentrate of a carboxylic acid having the formula (I) or an acid anhydride or ester thereof or the weight ratio of components (A) to (F) being such as to produce a concentrate having a TBN greater than 300 and a viscosity at 100° C of less than 1000 mm².s^-1 (cSt).