Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION
  • C10M159/00—Lubricating compositions characterised by the additive being of unknown or incompletely defined constitution
  • C10M159/12—Reaction products
  • C10M159/20—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products
  • C10M159/22—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products containing phenol radicals

Definitions

• 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.
• 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.
• TBN total base number
• 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.
• the equivalent ratio of alkaline earth metal moiety to phenol moiety in "normal” alkaline earth metal alkyl phenates is one.
• 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.
• 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.
• 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.
• this method involves relatively long batch times.
• 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.
• TBN total base number
• 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.
• 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:
• 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
• 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 C 10 to C 24 unbranched alkyl or alkenyl group, and R 1 is hydrogen, a C 1 to C 4 alkyl group or a -CH 2 -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(OR 1 ) x OR 2 wherein R is a C 1 to C 6 alkyl group, R 1 is alkylene, R 2 is hydrogen or C 1 to C 6 alkyl and x is an integer in the range 1 to 6 and as catalyst an inorganic halide.
• a small amount suitably up to 2% w/w of an acid, a suitable acid being stearic acid.
• stearic acid to the reactants can, it is said, enhance the ability of alkylphenates to minimise emulsion formation in water.
• 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:
• 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.
• 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.
• 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.
• 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 C 12 -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.
• R in the formula (I) is an unbranched alkyl group.
• Preferred acids of formula (I) are those wherein R is a C 10 to C 24 , more preferably C 18 to C 24 straight chain alkyl groups and R 1 is hydrogen.
• 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.
• 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.
• 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.
• 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.
• 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.
• 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.
• the TBN of the concentrate is greater than 350, more preferably greater than 400.
• 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 well known in the art.
• 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.
• 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.
• 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-(C 2 to C 4 ) 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-(C 2 to C 4 ) 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 (OR 1 ) x OR 2 wherein R is a C 1 to C 6 alkyl group, R 1 is an alkylene group, R 2 is hydrogen or C 1 to C 6 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 (CH 3 OCH 2 CH 2 OCH 2 CH 2 OH). Mixtures of glycols and glycol ethers of formula (II) may also be employed.
• 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. C 1 to C 4 , carboxylic acid, for example acetic acid.
• an inorganic halide for example ammonium chloride
• a lower, i.e. C 1 to C 4 carboxylic acid, for example acetic acid.
• carboxylic acid for example acetic acid.
• 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.
• 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.
• suitable diluents include 2-ethyl hexanol, iso-octanol, iso-heptanol and tri-decanol.
• sulphur that is sulphur additional to that already present by way of component (A)
• sulphur addition leads to the evolution of hydrogen sulphide, thereby to some extent detracting from the advantage of the invention as hereinbefore mentioned.
• the reaction is carried out in the presence of a further component which is a catalyst for the reaction.
• a catalyst for the reaction there may be used an inorganic halide which may suitably be either a hydrogen halide. an ammonium halide or a metal halide.
• the metal moiety of the metal halide may be inc. aluminium or an alkaline earth metal, preferably calcium.
• the chloride is preferred.
• Suitable catalysts include hydrogen chloride, calcium chloride, ammonium chloride, aluminium chloride and zinc chloride, preferably calcium cnloride.
• the amount of catalyst employed may be up to 2.0% wt/wt.
• 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).
• 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.
• the concentrates generally have desirable viscosity index properties. Such viscometric properties are advantageous because they facilitate processing (including filtration) of the concentrate.
• 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.
• 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-(C 2 to C 4 ) 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 anhydr
• 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.
• 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.
• 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.
• the concentrates of the present invention may also find application as fuels additives.
• TBN is the Total Base Number in mg KOh/g as measured by the method of ASTM D2896.
• a commercially available sulphurised calcium alkyl phenate derived from a C 12 -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).
• 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.
• 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.
• 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 As for Example 2 except that the temperature was 145°C instead of 165 °C in steps (d), (e) and (f).
• Example 2 As for Example 2 except that the temperature was 130 ° C instead of 165 °C in steps (d), (e) and (f).
• the filtration step (h) was very difficult.
• Example 3 demonstrates the desirability of using a catalyst in the process of the invention. In the absence of catalyst, although a lower V 100 was obtained, this was achieved at the expense of reduced incorporation of calcium and carbon dioxide, and moreover filtration was difficult.
• 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.
• step (h) The filtration rate in step (h) was slow.
• Example 3 As for Example 3 except that the ethylene glycol addition in step (d) was reduced from 32 g to 16 g.
• step (h) The filtration rate in step (h) was slow.
• 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.
• step (h) The filtration rate in step (h) was rapid.
• step (d) the pressure was 270 mm Hg.
• Example 3 As for Example 3 except that instead of 190 g 2-ethyl hexanol there was used 40 g.
• step (i) 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 C 18 ).
• This Example demonstrates that sulphurised calcium alkyl phenates derived from a mixture of C 12 /C 22 /C 24 alkyl phenols can be upgraded.
• Rape Top Fatty Acid can be used in the process of the invention.
• step (a) instead of stearic acid (63 g) there was used Tall Oil Fatty Acid (63 g).
• PIBSA polyisobutene succinic anhydride
• Example 16 As for Example 16 except that instead of Tall Oil Fatty Acid (63 g) there was used behenic acid (63 g).
• 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.
• 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.
• This Example demonstrates that an uncarbonated sulphurised calcium alkyl phenate of low initial TBN can be used in the process of the invention.
• This Example demonstrates that a low (150) TBN sulphurised calcium alkyl phenate can be upgraded to a high TBN product.
• 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).
• the filtration rate was rapid.

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• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Oil, Petroleum & Natural Gas (AREA)
• Organic Chemistry (AREA)
• Lubricants (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Catalysts (AREA)
• Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)

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• 1986
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