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 alkaline earth metal hydrocarbyl phenates and their sulphurised derivatives, their production and use thereof as lubricating oil additives.
• the present invention relates to concentrate additive compositions comprising alkaline earth metal hydrocarbyl phenates and their sulphurised derivatives having both a high total base number (TBN) and an acceptable viscosity, to their production and to their use as lubricating oil additives.
• TBN total base number
• One class of compounds generally employed to neutralise the acidic materials and disperse sludge within the lubricating oil are the metal alkyl phenates and sulphurised metal alkyl phenates, wherein the metal is an alkaline earth metal such as calcium, magnesium or barium. Both "normal” and “overbased” alkaline earth metal alkyl phenates have been employed.
• the term “overbased” is used to describe those 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" 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” metal alkyl phenates.
• One such method for preparing "overbased” alkyl phenates generally referred to as the “single lime addition” process comprises reacting an alkyl phenol, in the presence or absence of sulphur, lubricating oil, 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.
• TBN total base number
• carboxylic acids either in the production of alkaline earth metal alkyl phenates and their sulphurised derivatives or in association therewith in lubricating oil compositions is not new, see for example US-A-3,372,116; GB-A-1440261; US-A-4049560 and EP-A-0094814.
• US-A-3,372,116 discloses an improvement in the method for preparing a basic metal phenate by reacting at a temperature between about 25°C and the reflux temperature (A) a hydrocarbon-substituted phenol having at least 6 carbon atoms in the hydrocarbon substituent, a mixture of said phenol with up to an equivalent amount of hydrocarbon-substituted succinic acid or anhydride having at least about 6 carbon atoms in the hydrocarbon substituent, or a substantially neutral alkali metal or alkaline earth metal salt or either of the foregoing, (B) about 1-10 equivalents, per equivalent of (A), of a calcium or strontium base, and (C) carbon dioxide, which improvement comprises carrying out the reaction in the presence of about 0.002-0.2 equivalent, per equivalent of said calcium or strontium base, of a carboxylic acid having up to about 100 carbon atoms or an alkali metal, alkaline earth metal, zinc or lead salt thereof.
• the preferred carboxylic acids are those containing up to about 10 carbon atoms, more preferred being monocarboxylic acids containing up to 10 carbon atoms and alkyline earth metal salts thereof.
• water and a carboxylate salt are employed. Not only do we wish to avoid the presence of water but we also find that carboxylate salts can not be used in the process of the present invention because of their inherent insolubility in the system.
• the process of US-A-3,372,116 does not employ phenol to alkaline earth metal base ratios sufficient to produce phenates having TBNs in excess of 300.
• GB-A-1440261 discloses a lubricating oil composition
• a lubricating oil composition comprising a lubricating oil, a detergent or dispersant additive and a mixture of at least two carboxylic acids, one acid having a melting point of at least 20°C and not more than 30 carbon atoms per molecule, and another acid having a melting point of below 20°C, the weight proportion of low melting point acid to high melting point acid being between 1.5:1 and 8:1.
• the detergent may be an overbased phenate, those having a TBN of 50 to 100 being considered very suitable.
• the mixture of acids is present in an amount of 0.05 to 2.0 wt %.
• 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 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 given rise to sedimentation and foaming problems.
• the problem of EP-A-0094814 is not that of producing phenate additive concentrates having a TBN of greater than 300 and indeed the phenate additive concentrates produced by the process of the invention, although demonstrating overcoming the problems of stability and foaming, have TBN values of less than 300.
• the present invention provides an additive concentrate suitable for incorporation into a finished lubricating oil composition, the additive concentrate comprising:
• Component (a) of the composition 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 composition.
• Component (b) is a lubricating oil soluble sulphurised or non-sulphurised, preferably 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) or (ii).
• 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 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 carbon atoms.
• a particularly suitable alkyl phenol is the C12-alkyl phenol obtained by alkylating phenol with propylene tetramer.
• the alkyline earth metal hydrocarbyl phenate is modified by incorporation of either (i) or (ii).
• this is at least one carboxylic acid having the formula (I) or an acid anhydride, acid chloride or ester thereof.
• R in the formula (I) is an unbranched alkyl or alkenyl group.
• Preferred acids of formula (I) are those wherein R is a C10 to C24, more preferably C18 to C24 straight chain alkyl group and R1 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.
• suitable unsaturated acids of formula (I) include lauroleic acid, myristoleic acid, palmitoleic acid, oleic acid, gadoleic acid, erucic acid, ricinoleic acid, linoleic acid and linolenic 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, pal kernel oil, olive oil, corn oil, palm oil, castor oil, soyabean oil, sunflower oil, herring oil, sardine oil and tallow.
• Sulphurised acids and acid mixtures may also be employed.
• the carboxylic acid there may be used the acid anhydride, the acid chloride or the ester derivatives of the acid, preferably the acid anhydride. It is preferred however to use a carboxylic acid or a mixture of carboxylic acids.
• a preferred carboxylic acid of formula (I) is stearic acid.
• the alkaline earth metal hydrocarbyl phenate may be modified by incorporation of (ii), which is a di- or polycarboxylic acid containing from 36 to 100 carbon atoms or an acid anhydride, acid chloride or ester derivative thereof, preferably an acid anhydride thereof.
• (ii) is a polyisobutene succinic acid or a polyisobutene succinic anhydride.
• the carboxylic acid(s) having the formula (I), the di- or polycarboxylic acid, or the acid anhydride, acid chloride or ester thereof is incorporated in an amount from greater than 10% to 35%, more preferably from 12 to 20%, for example about 16% by weight based on the weight of the composition.
• An advantage of incorporating greater than 10% of the carboxylic acid or derivative thereof is generally a relativelylower 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 composition.
• the alkaline earth metal hydrocarbyl phenate may be either sulphurised or non-sulphurised, preferably sulphurised.
• sulphur may be present in the composition in an amount in the range from 1 to 6, preferably from 1.5 to 3% by weight based on the weight of the composition.
• carbon dioxide may be present in the composition in an amount in the range of from 5 to 20, preferably from 9 to 15% by weight based on the weight of the composition.
• the TBN of the composition is greater than 350, more preferably greater than 400.
• the composition may have a viscosity measured at 100°C of less than 1000 cSt, preferably less than 750 cSt, more preferably less than 500 cSt.
• an additive concentrate suitable for incorporation into a finished lubricating oil which concentrate is obtainable by reacting at elevated temperature (A) either (i) a hydrocarbyl phenol or (ii) a hydrocarbyl phenol and sulphur, (B) an alkaline earth metal base added in either a single addition or in a plurality of additions at intermediate points during the reaction, (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 2 to less than 40% by weight based on the weight of the concentrate of either (i) a carboxylic acid having the formula (I) or an acid anhydride, acid chloride or ester thereof or (ii)
• the present invention provides a process for the production of an additive concentrate for incorporation into a finished lubricating oil which process comprises reacting at elevated temperature components (A) to (F) as hereinbefore described, the weight ratios of components (A) to (F) being such as to produce a concentrate having a TBN greater than 300.
• Component (A) of the reaction mixture is either (i) a hydrocarbyl phenol or (ii) a hydrocarbyl phenol and sulphur.
• component (A) (i) the product is an alkaline earth metal hydrocarbyl phenate and using component (A) (ii) the product is a sulphurised alkaline earth metal hydrocarbyl phenate.
• the hydrocarbyl phenol employed is that alkyl phenol from which is derived the desired hydrocarbyl phenate moiety as hereinbefore described.
• 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 alkyl phenol and will be higher than the amounts generally employed in prior art processes.
• the weight ratio of component (B) to component (A) may suitably be in the range from 0.2 to 50, preferably from 0.4 to 10.
• 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) in order to produce an additive concentrate having a TBN greater than about 350 and a viscosity at 100°C of less than 1000 cSt it is particularly desirable to add component (B) in at least two, and preferably more additions and to add component (F) in an amount greater than 10% by weight based on the weight of the additive concentrate product.
• Component (C) is either a polyhydric alcohol having from 2 to 4 carbon atoms, a di- or tri- (C2 to C4) glycol alkyl ether.
• the polyhydric alcohol may suitably be either a dihydric alcohol, for example ethylene glycol or propylene glycol, 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) x OR2 (II) 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.
• 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.
• an inorganic halide for example ammonium chloride
• 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 additive concentrate.
• Component (E) is carbon dioxide, which may be added in the form of a gas or a 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). In order to produce a concentrate having a TBN greater than about 350 the carbon dioxide is preferably added subsequent to each of two or preferably more additions of component (B).
• Component (F) is either a carboxylic acid of formula (I), a di- ­or polycarboxylic acid containing from 36 to 100 carbon atoms, or an acid anhydride, an acid chloride or ester thereof as hereinbefore described with reference to the additive concentrate composition.
• the amount of the aforesaid required to provide from greater than 2 to less than 40% by weight based on the weight of the concentrate will be to a first approximation the amount desired 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.
• 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 zinc, 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 chloride.
• the amount of catalyst employed may be up to 2.0% wt/wt.
• reaction of components (A) - (F) and also the carbon reaction may be carried out at elevated temperatures in the range from 120 to 200, preferably from about 130 to 165°C, through the actual temperatures 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 distillations 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.
• High viscosity concentrates for example concentrates having a viscosity at 100°C greater than 1000 cSt, and also having a high TBN, for example greater than 350, may be diluted by addition of further lubricating oil whilst maintaining a TBN greater than 300, thereby facilitating filtration.
• the present invention provides a finished lubricating oil composition which composition comprises a lubricating oil and sufficient of the additive concentrate as hereinbefore described to provide a TBN in the range from 0.5 to 120.
• the finished lubricating oil composition contains sufficient of the additive concentrate to provide a TBN in the range from 0.5 to 100.
• the amount of additive concentrate present in the finished lubricating oil will depend on the nature of the final use. Thus, for marine lubricating oils the amount of additive concentrate 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 composition.
• viscosity index improvers 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 composition.
• the additive concentrate 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.
• the viscosity was measured by the method of ASTM D445.
• Example 1 As for Example 1, except that the amount of lime in the charge was increased from 82 g to 117 g corresponding to the total amount of lime added in Example 1 in two additions.
• step (c) As for Example 1 except that the amount of carbon dioxide added in step (c) was increased from 40 g to 60 g and steps (d), (e), (f) and (g) were omitted. The filtration rate in the final step was slow.
• This Example demonstrates that an additive concentrate phenate having a high TBN can be produced in a single lime addition process but under the conditions of the Example the viscosity of the product is unacceptable for commercial operation without dilution with lubricating oil.
• step (g) the amount of carbon dioxide was increased from 20 g to 40 g and the following steps were added after step (g) and before steps (h) and (i):
• Example 1 As for Example 1 except that the amount of lubricating oil was reduced from 131 g to 158 g and the amount of stearic acid was reduced from 70 g to 43 g.
• step (d) the mixture was cooled to 135°C instead of 125°C.
• Example 2 demonstrates by comparison with Example 1 that although a high TBN product can be produced at an acid level less than 10% w/w the viscosity of the product is high.
• This Example demonstrates that a high TBN product having an acceptable viscosity can be obtained using a stearic acid addition of 27.5% w/w based on the weight of the final product.
• Example 5 As for Example 5 except that the amount of C12-alkyplhenol was reduced from 35.3 g to 15.6 and the amount of stearic acid was increased from 109.1 g to 128.7 g.
• This Example demonstrates that a high TBN product can be obtained at a stearic acid content of 30.9% w/w.
• the Examples demonstrate that an additive concentrate having a TBN greater than 300 can be produced in a single lime addition process over a range of stearic acid contents from 2.6 to 29.7% w/w based on the weight of the concentrate.
• This Example demonstrates that an additive concentrate having a TBN as high as 450 and an acceptable viscosity can be produced by the process of the invention.
• C12-alkyl phenol 64 g
• Lubricating oil (SN 100) 111 g
• Sulphur 20 g
• Stearic acid 59 g
• Acetic acid 2 g
• Ammonium chloride 3 g Methyl diglycol: 40 g
• step (c) instead of methyl diglycol (90 g) there was used ethylene glycol (31 g) and in steps (d) and (g) the mixture was held at 165°C/700 mm Hg for 10 minutes instead of 1 hour.
• Example 16 As for Example 16 except that instead of the C18-alpha-olefin (38 g) there was used a polyisobutene having an M n of 500 (38 g).
• This Example demonstrates that a high TBN additive concentrate can be obtained using a Tallow Fatty Acid.

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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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