GB1604609A

GB1604609A - Carbonated low ash base lubricant additive

Info

Publication number: GB1604609A
Application number: GB24074/77A
Authority: GB
Original assignee: Orobis Ltd
Current assignee: Orobis Ltd
Priority date: 1977-06-09
Filing date: 1977-06-09
Publication date: 1981-12-09
Also published as: BE867955R; JPS5410306A; NL7806280A; DE2825463A1; FR2393845A2

Description

(54) CARBONATED LOW ASH BASE LUBRICANT ADDITIVE (71) We, OROBIS LIMITED, of Devonshire House, Mayfair Place, London, W1X 6AY, a British Company, do hereby declare the invention for which we pray that a patent may be granted to us, and the method by which it is to be performed to be particularly described in and by the following statement:- The present invention relates to basic lubricant additives.

Lubricating oils used under the severe conditions of diesel engines are highly compounded so as to provide neutralisation of acids derived from the sulphur in the fuel and from oxidation of hydrocarbons, both of the fuel and oil, dispersancy so as to maintain sludge-forming precursors dispersed in the oil, improved wear protection and oiliness properties, as well as to enhance other attributes of the oil. In addition to the requirements normally needed in a diesel lubricating oil, those oils which find use in railway diesel engines have the additional requirement of not being corrosive or reactive to silver. Silver bearings are used in a preponderant number of diesel engines today.

The desirability of having a single additive providing multifunctional properties is evident in the efficiency and economy in the manufacture and use of a single additive as compared to a plurality of additives. However, because of the severe operating conditions under which a lubricating oil performs in diesel engines, it is frequently found that additives, while effectively performing a particular function, will tend to degrade and enhance deposit formation. Therefore, in designing any particular additive, it is essential not only that it fulfils the function(s) for which it has been designed, but that it be stable under the conditions of use or degrades slowly to materials which do not enhance deposit formation.

Alkaline earth metal phenoxides or phenates have been used in lubricating oils for a long period of time. Both sulphurised alkylphenols and Mannich bases have been employed in lubricating oils. U.S. Patents Nos. 2,459,114 and 2,459,116 teach the preparation of Mannich products employing polyatnines with sulphur-bridge alkyl phenols. U.S. Patent No. 3,454,497 prepares a Mannich base using methylamine, formaldehyde and alkylphenols for use in lubricating oils. Other patents of interest include US Patents Nos. 2,810,697, 3,372,118, 3,429,812, 3,472,773, 2,527,279, 2,763,616, 3,368,972, 2,410,911, 2,962.442, 3,413,347 and 3,340,190.

British patent specification No. 1,352,760 describes and claims a dispersant detergent suitable for use as a lubricating oil additive, comprising the reaction product obtainable by the neutralisation with an alkaline earth metal oxide or hydroxide of a sulphurised alkyl phenol containing at least 4 weight percent sulphur and a Mannich base containing at least 2 weight percent nitrogen and having a molecular weight of at least 600 and prepared from a C1 to C, alkylamine, an alkylphenol and formaldehyde, the neutralisation being carried out in the presence of a hydroxylic solvent and at an elevated temperature so that molecular bonds are formed between the Mannich base and the sulphurised alkylphenol in addition to the bridging bonds created by the alkaline earth metal.

Our British patent specification No. 1,568,959 describes and claims a process for the production of a product suitable for use as a lubricating oil additive which process comprises reacting at elevated temperature and in the presence of a hydroxylic solvent an alkaline earth metal oxide or hydroxide with a mixture of either: (A) a sulphurised alkylphenol containing from 4 to 20 weight percent sulphur or (B) a mixture contaming for the most part a sulphurised alkylphenol and for the remaining part an alkaline earth metal salt of a sulphurised alkylphenol, the mixture containing from 4 to 20 weight percent sulphur and, (C) a Mannich base containing at least 2 weight percent nitrogen and having a molecular weight of at least 600 and prepared from an alkylene diamine or a polyalkylene polyamine having the structural formula: H2N+alkyleneNH+H (I) wherein n is an integer from 1 to 10 and the alkylene group has from two to eight carbon atoms, an alkylphenol and formaldehyde, the amount of alkaline earth metal oxide or hydroxide reacted being sufficient to provide more than 1 and less than 1.75 equivalents of alkaline earth metal per equivalent of alkylphenol in the product.

Furthermore our British patent specification No. 1,581,747 describes and claims a process for the production of a product suitable for use as a lubricating oil additive which process comprises reacting at elevated temperature and in the presence of a hydroxylic solvent an alkaline earth metal oxide or hydroxide with a mixture of either: (A) a sulphurised alkylphenol containing from 4 to 20 weight percent sulphur or (B) a mixture containing for the most part a sulphurised alkylphenol and for the remaining part an alkaline earth metal salt of a sulphurised alkyl phenol, the mixture containing from 4 to 20 weight percent sulphur and, (C) a Mannich base containing at least 2 weight percent nitrogen and having an average molecular weight of at least 600 and prepared from an alkylene diamine or a polyalkylene polyamine having the structural formula: H2N+aLkylenc"NH~H (I) wherein n is an integer from 1 to 10 and the alkylene group has from two to eight carbon atoms, an alkylphenol and formaldehyde, thereby forming an intermediate product, the amount of alkaline earth metal oxide or hydroxide reacted being sufficient to provide more than 1 and less than 1.75 equivalents of alkaline earth metal per equivalent of alkylphenol in the intermediate product and thereafter reacting the intermediate product with carbon dioxide.

Compounds produced by the process involving post-treatment with carbon dioxide have substantially lower viscisities than products which have not been so treated.

It has now been found that the viscosity of the product can also be reduced by carbonating the sulphurised alkylphenol/salt mixture prior to reaction with the Mannich base and alkaline earth metal oxide or hydroxide.

Accordingly the present invention provides a process for the production of a product suitable for use as a lubricating oil additive which process comprises reacting at elevated temperature and in the presence of a hydroxylic solvent an alkaline earth metal oxide or hydroxide with a mixture of: (B) a mixture containing for the most part a sulphurised alkylphenol and for the remaining part an alkaline earth metal salt of a sulphurised alkyl phenol, the mixture containing from 4 to 20 weight percent sulphur and, (C) either, a Mannich base containing at least 2 weight percent nitrogen and having an average molecular weight of at least 600 and prepared from an alkylene diamine or a polyalkylene polyamine having the structural formula: H2N+alkyleneNH+H (I) wherein n is an integer from 1 to 10 and the alkylene group has from two to eight carbon atoms, an alkylphenol and formaldehyde, or the precursors of the Mannich base, the amount of alkaline earth metal oxide or hydroxide reacted being sufficient to pro vide more than 1 and less than 1.75 equivalents of alkaline earth metal per equivalent of alkylphenol in the product, and afterwards removing the hydroxylic solvent, characterised in that the sulphurised alkylphenol/salt mixture is reacted with carbon dioxide before it is reacted with the alkaline earth metal oxide or hydroxide.

It is believed that in the process of reacting the carbonated sulphurised alkyl phenol salt mixture (B) with the Mannich base molecular bonds are formed between the Mannich base and the sulphurised alkylphenol in addition to the bridging bonds created by the alkaline earth metal.

The cmbomated mixture (B).

Sulphurised alkylphenols and sulphurised alkyl phenol/salt mixtures are well known materials for use in lubricating oils.

The sulphurised alkylphenol preferably has the following formula:

wherein R2 is an alkyl group containing from 8 to 36 carbon atoms, more usually from 10 to 30 carbon atoms with the average number of carbon atoms being in the range of 10 to 26, yl is an integer in the range from 1 to 9, more usually from 1 to 5, averaging over the entire composition in the range from 2 to 4, and n1 is an integer from 1 to 5, more usually from 1 to 3. There may be small amounts not more than about 10 weight percent of sulphurised phenol having y1 greater than 9.

The carbonated sulphurised mixture (B) contains at least 4 weight percent sulphur and not more than 20 weight percent sulphur, more usually from 8 to 18 weight percent sulphur.

The aliphatic hydrocarbon groups designated R2 in the structural formula (II) may suitably be in the ortho, or para-positions, but preferably they will be predominantly in the para-positions since ortho-substituted phenols act as chain terminators in the condensation of sulphur and alkylphenol. The presence of branched chain alkyl group results in reduced amounts of ortho-substituted phenols, and branched-chain alkyl groups are therefore preferred.

Sulphurised alkylphenol/salt mixtures may be prepared by combining alkylphenol, sulphur, calcium oxide, or calcium hydroxide and glycol at an elevated temperature, driving off the water and hydrogen sulphide, followed by isolation of the sulphurised alkyl-phenol. See for example U.S. Patent No. 2,989,466.

According to the present invention a carbonated mixture (B) is reacted with the Mannich base (C). A carbonated sulphurised all:ylphenol/salt mixture is produced by reacting a sulphurised alkylphenol/salt mixture with carbon dioxide, preferably at elevated pressure, although the pressure is not critical.

The carbon dioxide may be reacted in an amount from 1 to 25, preferably from 1 to 15% by weight based on the weight of sulphurised alkylphenol/salt mixture.

The carbon dioxide may suitably be introduced as a gas, in which case it may be blown under pressure into the reaction mixture, or as a solid, introduction as a solid being preferred.

A preferred method for producing the carbonated mixture (B) consists in combining an alkylphenol, sulphur, calcium oxide or hydroxide and glycol at an elevated temperature, e.g. 140 to 150 C, driving off water and hydrogen sulphide, introducing carbon dioxide into the reaction mixture and finally removing the glycol solvent under appropriate conditions. Alternatively the carbon dioxide may be introduced after removal of the glycol solvent.

The Mannich base (C).

The Mannich bases which are employed may be prepared for instance bv combining at elevated temperatures, an alkylphenol, formaldehyde and the alkylene or polyalkylene polyamine having the structural formula (I). The alkylphenol may suitably contain from 4 to 40 carbon atoms, preferably from 9 to 25, even more preferably from 10 to 14 carbon atoms m the alkyl group. The formaldehyde may be added in the form of an aqueous solution (formalin) or in a polymeric form e.g.

paraformaldehyde. A method for preparing the Mannich bases may be found in UK Application No. 25316/71 (Serial No: 1,345,030). US Patent No: 3,454,497 describes an additional method for preparing Mannich bases employing primary amines.

The preferred alkylene polyamines having the formula (L) are the ethylene pdlyamines wherein the alkylene group has two carbon atoms. A preferred ethylene polyamine is diethylene triamine. Other polyalkylene polyamines of formula (I) which may be used include ethylene diamine, tetraethylene pentamine and triethylene tetramine. Further alkylene polyamines which may be used include, for example, propylene polyamines and butylene polyamines. The alkylene polyamines may be prepared by methods well-known in the art.

The Mannich base (undiluted) contains at least 2 weight percent nitrogen and preferably not more than 10 weight percent nitrogen. The average molecular weight, as determined by osmometry, is at least 600, more usually at least 700, and normally not exceeding 5,000.

The Mannich base may be in the mono- or bis-form, the particular form being governed by the ratio cf alkylphenol to formaldehyde to amine in the preparative mixture.

The alkaline earth metal oxide or hydroxide.

The alkaline earth metal oxide or hydroxide is preferably an oxide or hydroxide of calcium or barium hydroxide being most preferred.

The hydroxylic solvent.

Suitable hydroxylic solvents include ethylene gyccl, propylene glycol, butane diols and methanol. 1,3-, 1,4-, or 1,2-butane diol may be employed. The preferred hydroxylic solvent is ethylene glycol.

The products of the present invention are complex in nature. Because of the variety of the pcssible reacticns which might cccur during the formation of the product any attempt to define the composition by means of a general structural formula would be meaningless.

Reaction of carbonated mixture (B) and Mannich base (C).

The Mannich base (C) and the carbonated mixture (B) are advantageously mixed in an equivalent ratio (based on phenol) in the range of 0.2-5:1, more usually 0.3-3:1. In addition to the abcve reactants are included an alkaline earth metal oxide or hydroxide, preferably hydroxide, and a hydroxylic solvent, usually ethylene glycol.

The amount of alkaline earth oxide or hydroxide added is sufficient to provide more than 1 and less than 1.75 equivalents, preferably more than 1 and less than 1.5 equivalents of alkaline earth metal per equivalent of alkylphenol in the final product.

The amount of the hydroxylic solvent will vary with the particular solvent em ployed and the optimum amount can readily be determined by trial. Since ethylene glycol is the preferred solvent, only its use will be discussed in detail. The amount of ethylene glycol employed may normally be from 5 to 35 weight percent, preferably from 7 to 20 weight percent, of the total reaction mixture.

In addition to the ethylene glycol, an inert hydrocarbon diluent may also be present. These inert diluents may be of service to aid in the handling of the reactants, lowering the viscosity of the reaction mixture, and enhancing the ease of isolation of the product. In view of the intended use of the compositions of the invention, mineral oils cf lubricating viscosity may be used and the product recovered as a solution in the mineral oil. Normally the inert diluent may be present in the reaction mixture, if at all, in amounts from 3 to 65 weight percent, more usually 5 to 50 weight percent of the total reaction mixture.

Ccnveniently, a small amount of an anti-foaming agent or foaming supressant may be employed. The foam suppressant is suitably present in the reaction mixture in amounts of 1 x 10-3 to 1 x 10-5 weight percent. Conventional foam suppressants may be employed.

Additionally a small amount of a neutral alkaline earth metal sulphonate may suitably be included in the reaction mixture to facilitate the dispersal of the alkaline earth metal oxide or hydroxide throughout the mixture and improve the reaction rate.

The neutral alkaline earth metal sulphonate is preferably calcium sulphonate. The amount of alkaline earth metal sulphonate added may suitably be in the range from 1 to 5% by weight.

The reaction may be conveniently carried out by mixing the carbonated mixture (B), the Mannich base (C), the alkaline earth metal oxide or hydroxide, the hydroxylic solvent e.g. ethylene glycol, and cpticnally the inert diluent. Preferably, prior to the addition to the ethylene glycol, the mix.ure is heated to at least 90 C, but below the temperature at which the reaction is te be carried out. After addition of the ethylene glycol, the temperature may be raised so as to distil water overhead, removing the water of reaction. Usually the temperature during removal of water will range from 125 to 160O C. The time required for the removal of water will usually be from about 30 minutes to 3 hours.

Reaction of carbonated mixture (B) and precursors of Mannich base (C).

Alternatively the reaction may advantageously be carried out by first reacting the carbonated mixture (B) with the precursors of the Mannich base (C) to form a mixture containing carbonated mixture (B) and Mannich base (C) and thereafter reacting the mixture with the alkaline earth metal oxide or hydroxide in the presence of the hydroxylic solvent e.g. ethylene glycol.

The carbonated mixture (B) may suitably be reacted with the alkylphenol in an equivalent ratio (based on phenol) in the range of from 0.2 to 10:1, preferably 0.2 to 5:1, even more preferably about 1:1. The alkylene or polyalkylene polyamine may suitably be present in an amount cf from 1 to 3 moles for every 1 to 3 moles of alkylphenol present in the reaction mixture. The formaldehyde may suitably be present in an amount of from 0.75 to 1.25 moles for every 1 to 3 moles of alkylphenol present in the reaction mixture.

The reaction between the carbonated mixture (B), the alkylphenol, the alkylene or polyalkylene polyamine and the formaldehyde may be effected by mixing the reactants together and heating them to a temperature sufficient to cause the reaction to occur. The reaction is preferably carried out in the presence of a solvent. Preferred solvents are the water-immiscible solvents including water-insoluble alcohols (e.g.

amyl alcchol) and hydrocarbons. Hydrocarbon solvents boiling in the range 50 to 2000 C, e.g. benzene, toluene and xylene are the preferred water-immiscible solvents. Of these the most preferred solvent is toluene. Suitably the solvent may be employed in an amount from 1 to 50, preferably from 3 to 25, even more preferably from 5 to 10% by weight based on the total weight cf the reaction mixture.

Reaction may suitably be effected at a temperature in the range 50 to 150, preferably 50 to 1300 C. When a solvent is employed it is preferred to conduct the reaction at the reflux temperature of the reaction mixture. For example when toluene is used as the solvent the condensation suitably proceeds at 110 to 1300 C. At the end cf the reaction the temperature may be raised to about 1500 C in order to remove the tcluene solvent. The water formed in the reaction codistils together with the water-immiscible solvent, permitting its removal from the reaction zone. During this solvent removal step the pressure may be reduced. The time required to complete the reaction depends upon the reactants employed and the reaction temperature used.

Reaction times from 1 to 8 hours are usually sufficient.

Reaction of the complex mixture so-obtained with the alkaline earth metal oxide or hydroxide may be effected in the same manner as hereinbefore described for the reaction between the mixture (B) and the pre-formed Mannich base (C).

Reaction in the presence of a carboxylic acid.

According to another aspect of the present invention reaction of the carbonated mixture (B) with the Mannich base or the precursors thereof is effected in the presence of a carboxylic acid.

Whilst any carboxylic acid may be present during the reaction the presence of a C1 to Cic carboxylic acid is preferred. A particularly preferred carboxylic acid is acetic acid. The carboxylic acid may be present in an amount of from 0.001 to 0.5 moles, preferably from 0.02 to 0.1 moles per mole of alkylphenol present in the reaction mixture.

Further reaction with carbon dioxide.

The product may be further reacted with additional amounts of carbon dioxide.

Whilst the product may be reacted with carbon dioxide at a later stage in the proceedings after the hydroxylic solvent has been removed it is preferred to react the product with carbon dioxide in the presence of the hydroxylic solvent i.e. before removal of the solvent. The carbon dioxide may conveniently be introduced into the product m;tire bv blowing under pressure. Reaction with carbon dioxide is preferably effected at the temperature employed during the formation of the product i.e. 140 to 1500 C, although higher temperatures may be employed if desired. The additional amount of carbon dioxide added may suitably be in the range 1 to 15, preferably 1 to 8 percent by weight, based on the total weight of the reaction mixture.

Remo7vaI of hydroxylic solves t.

Whilst incorporation ci a hydroxylic solvent facilitates the formation of the product its presence is not desirable in the lubricating compositions in which the product is most advantageously employed. The hydroxylic solvent is therefore removed after formation of the product. In the case of ethylene glycol as solvent this may be achieved by raising the temperature te below 200 C and reducing the pressure sufficiently to allow its distillation. Usually the temperature during removal of ethylene glycol may be in the range from 140 to 2000 C, preferably from 160 to 1900 C. The pressure may be varied depending upon the temperature and rate of distillation required. The reduced pressure may vary from about 0.01 to 0.8 atmospheres. Ethylene glycol may be removed over a period of from 15 minutes to 9 hours. The time, whilst not a critical factor, should not be unduly protracted, and will depend on the capacity of the equipment, the amount of reactants, the degree of foaming and the ability to control the temperature and the rate of the removal of distillates.

When no further ethylene glycol comes over, the reaction mixture may be cooled.

At this stage it is preferred to add an inert diluent. Depending on the presence and amount of inert diluent already in the reaction mixture, the temperature is preferably maintained above 1500 C prior to sufficient dilution with a convenient diluent. The mixture can become extremely viscous, and solution into a diluent is difficult below a temperature of 1500 C. Any convenient diluent may be used, but in view of the intended ultimate use normally a hydrocarbonaceous lubricating oil will be used as the diluent. Depending on the end use various hydrocarbonaceous lubricating oils may be employed. Whether further diluent is added or not, it is preferred to filter off any undesirable insoluble compounds.

The product of the invention.

The product as formed (independent of any diluent) will normally have alkalinity value (ASTM Test -- D2896) in mg KOH/g. in the range 100 to 450, more usually 175 to 400. The product will normally provide in elemental analysis from 2 to 12, more usually from 3 to 7, weight percent alkaline earth metal, at least 0.1 to 5, more usually from 0.5 to 4, weight percent nitrogen, and from 0.8 to 10, more usually from 1 to 8 weight percent sulphur. In a 100 neutral oil, (100 being the viscosity at 100 F in SUS) at an alkaline earth metal concentration of 0.88 molar (3.5 weight percent for Ca), the viscosity at 2100 F will normally be in the range of 200 to 3000 SUS, more usually in the range of 200 to 1,500 SUS.

Formulation of the products of the invention.

As diluted the product is ready to be employed as a concentrate for formulating finished lubricating oils or may have added thereto other conventional additive com- pounds.

The invention therefore additionally provides a concentrate composition suitable for formulating finished lubricating oils comprising a minor proportion of a hydro carbonaceous lubricating oil and a major proportion of an additive package consisting of, or containing, the hydroxylic solvent-free compound obtained as herein- before described.

The additive package may consist entirely of the hydroxylic solvent free compound as hereinbefore described in an amount up to 95 w/w based on the total weight of the concentrate composition. Alternatively the additive package may contain at least 5% w/w of the hvdroxylic solvent free compound as hereinbefore described and up to 90% w/w of additives, based on the total weight of the concentrate composition. The other additives may be, for example, VI improvers, pour-point depressants, anti-foam agents, oxidaticn inhibitors, extreme pressure agents or any of the additives commonly used in lubricating oil formulations.

According to another aspect of the present invention there is provided a finished lubricant composition comprising a major proportion of a lubricant base oil and a minor proportion of the concentrate composition as hereinbefore described.

The lubricant base oil may be a mineral oil derived from petroleum or a synthetic oil based, for example, cn esters.

Ccnventional lubricant additives may be incorporated into the finished lubricant composition to supplement any already present in the concentrate composition.

Although the compounds of the present invention have similar alkalinity reserves to conventional additives their ash content is very much lower.

The invention will now be illustrated with reference to the following Examples in which only Examples 1 and 2 are examples of the present invention.

Example A.

Preparation of sulphurised alkylphenol/salt mixture.

A mixture of 834 g of a C12-alkylphenol, prepared by alkylating phenol with propvlene tetramer, 55.5 g of calcium hydroxide and 240 g of sulphur were charged to a Z-litre flask and heated to 1250 C and then 32 g of ethylene glycol were added. The reaction temperature was raised to 1500 C and the pressure reduced to 210 mm Hg and held at that value for 1 hour.

The temperature was then further raised to 1900 C (base temperature) and the pressure reduced to 50 mm Hg for a period of 2 hours during which time all the ethylene glycol was removed. The product was then cooled to 1200 C, 396 g of lq0 Solvent Neutral Lube Oil was added and the product filtered.

The product was analysed for Alkalinity Value (A.V.)* and S content and the viscosity measured at 2100 F. The results are given in Table 1.

Example B.

Preparation of carbonated sulphurised alkylphenol/salt mixture (B).

Example A was repeated except that after the reaction temperature had been raised to 1500 C and the pressure reduced to 50 mm Hg for 1 hour the mixture was reacted with 45 g carbon dioxide.

The Alkalinity Value*, S content and viscosity at 2100 F values are given in Table 1.

* Throughout the specification A.V. represents the alkalinity value as measured by the procedure described in ASTM D2896.

TABLE 1

S Content r Vis 210 Example (O gong KOH)g) (cS) A 10.98 55.7 131.2 B I 10.58 51.0 52.5 Example C.

Preparation of Mannich base (C).

A mixture of 278 g (1 mole) of a C1 -alkylphenol, prepared by alkylating phenol with propylene tetramer, 51.5 g (0.5 mole) of diethylene triamine, 30 g (1 mole) of paraformaldehyde and 2 litres of toluene were heated to reflux and the water removed via a Dean and Stark head.

1 litre of water was added to the mixture and then removed together with the toluene solvent. A maximum temperature of 1600 C was then maintained for 1 hour at a pressure of 40 mm Hg.

Example 1.

346 g of the 74% active Mannich base (C) from Example C and 255 g of the carbonated sulphurised alkylphenol/salt mixture (B) from Example B i.e. the sulphurised alkylphenol/salt mixture which had been reacted with carbon dioxide, were mixed together at 125 C. 46.3 g calcium hydroxide and 150 g ethylene glycol were then added. The pressure was reduced to 500 mm Hg and the temperature held at 1250 C for 15 mins after which the

TABLE 2

Vis A.V. Ca content N content 210 Example (cS) (mg KOH/g) (%) (%) 1 492 207 4.15 2.12 D 602 185 3.63 1.96 It can be seen from an examination of Table 2 that reaction of the sulphurised alkyl phenol/salt mixture with carbon dioxide prior to reaction with the Mannich base and alkaline earth metal oxide or hydroxide results in a lower viscosity product.

Example E.

Preparation of sulphurised alkylphenol/salt mixture.

2344 g ( 8 moles) of a Cl2-alkylphenol, 512 g (16 moles) of sulphur and 177.6 g (2.4 moles) calcium hydroxide were heated to 125 C and 99 g ethylene glycol added.

The temperature was raised to 1500 C and the pressure reduced to 500 mm Hg pressure, these conditions being maintained for 1 hour.

The product was then vacuum stripped to a base temperature of 1900 C, 50 mm Hg pressure for 2 hours.

On cooling to 1200 C, the vacuum was released and 682 g 100 Solvent Neutral Lube Oil added. The product was then filtered.

The product was analysed for calcium and sulpur content and the viscosity measured at 210 F. The results are given in Table 3.

Example F.

Preparation of carbonated sulphurised athyIphenol/salt mixture (B).

The same ratios of reactants and preparative technique as described in Example E was used except that prior to vacuum stripping the reaction mixture was carbonated with 3% by weight, based on the total reactants, solid carbon dioxide at atmospheric pressure.

The product was analysed for calcium and sulphur content and the viscosity measured at 2100 F. The results are given in Table 3.

TABLE 3

Sulphur content Calcium content Vis 1O Example ( o) (%) (cS) 120 E 9.03 3.29 328 9.43 F 9.43 3.30 133.8 Example G.

703 g C12-alkylphenol, 742 g of the sulphurised alklphenol/salt mixture from Example E, 250 g 100 Solvent Neutral Lube Oil, 206 g diethylamine triamine and 90 g paraformaldehyde were heated at 1300 C over a period of 1 hour and held at that temperature for 1 further hour. The water formed was removed by normal distillation techniques.

248 g ethylene glycol and 148 g calcium hydroxide were then added and the temperature raised to 175 C at which value it was held for 1 hour. The product was then vacuum stripped to a bottom temperature of 200 C, 20 mm Hg pressure for hour.

On cooling to 1250 C, 227 g of 100 Solvent Neutral Lube Oil were added and the material filtered.

The product was analysed for calcium and nitrogen content and the alkalinity value and viscosity at 2100 F measured. The results are given in Table 4.

Example 2.

The preparative procedure of Example G was repeated with the same quantities of reactants, except that 754 g of the carbonated sulphurised alkyl phenol/salt mixture (B) from Example F was used in place of the sulphurised alkylphenol/salt mixture from Example E and 224 g of 100 Solvent Neutral Lube Oil were added on completion of the preparation.

The product was analysed for calcium and nitrogen content and the alkalinity value and viscosity at 210O F measured. The results are given in Table 4.

TABLE 4

Calcium Nitrogen Alkalinity Viscosity at content content value 210 F Example (%) (%) (mgKOH/g) (cS) G 4.04 3.35 232 884 2 3.89 3.23 237 689 WHAT WE CLAIM IS: 1. A process for the production of a product suitable for use as a lubricating oil additive which process comprises reacting at elevated temperature and in the presence of a hydroxylic solvent an alkaline earth metal oxide or hydroxide with a mixture of: (B) a mixture containing for the most part a sulphurised alkylphenol and for the remaining part an alkaline earth metal salt of a sulphurised alkylphenol, the mixture containing from 4 to 20 weight percent sulphur and, (C) either a Mannich base containing at least 2 weight percent nitrogen and having an average molecular weight of at least 600 and prepared from an alkylene diamine or a polyalkylene polyamine having the structural formula: H2N+all:ylenNHH (I) wherein n is an integer from 1 to 10 and the alkylene group has from 2 to 8 carbon atoms, an alkylphenol and formaldehyde, or the precursors of the Mannich base, the amount of alkaline earth oxide or hydroxide reacted being sufficient to provide more than 1 and less than 1.75 equivalents of alkaline earth metal per equivalent of alkylphenol in the product, and afterwards removing the hydroxylic solvent, characterised in that the sulphurised alkylphenol/salt mixture is reacted with carbon dioxide before it is reacted with the alkaline earth metal oxide or hydroxide.

2. A process according to claim 1 wherein the sulphurised alklphenol has the structural formula:

wherein R2 is an alkyl group containing from 8 to 36 carbon atoms, yl is an integer in the range from 1 to 9 and nl is an integer m the range from 1 to 5.

3. A process according to claim 2 wherein in the sulphurised alkylphenol of formula (II) R is an alkyl group containing from 10 to 30 carbon atoms with the average number of carbon atoms being in the range 10 to 26, y1 is an integer in the range from 1 to 5, averaging over the entire composition in the range from 2 to 4, and n' is an integer from 1 to 3.

**WARNING** end of DESC field may overlap start of CLMS **.

Claims

**WARNING** start of CLMS field may overlap end of DESC **.

Example 2.

The preparative procedure of Example G was repeated with the same quantities of reactants, except that 754 g of the carbonated sulphurised alkyl phenol/salt mixture (B) from Example F was used in place of the sulphurised alkylphenol/salt mixture from Example E and 224 g of 100 Solvent Neutral Lube Oil were added on completion of the preparation.

The product was analysed for calcium and nitrogen content and the alkalinity value and viscosity at 210O F measured. The results are given in Table 4.

TABLE 4

Calcium Nitrogen Alkalinity Viscosity at content content value 210 F Example (%) (%) (mgKOH/g) (cS) G 4.04 3.35 232 884 2 3.89 3.23 237 689 WHAT WE CLAIM IS: 1. A process for the production of a product suitable for use as a lubricating oil additive which process comprises reacting at elevated temperature and in the presence of a hydroxylic solvent an alkaline earth metal oxide or hydroxide with a mixture of: (B) a mixture containing for the most part a sulphurised alkylphenol and for the remaining part an alkaline earth metal salt of a sulphurised alkylphenol, the mixture containing from 4 to 20 weight percent sulphur and, (C) either a Mannich base containing at least 2 weight percent nitrogen and having an average molecular weight of at least 600 and prepared from an alkylene diamine or a polyalkylene polyamine having the structural formula: H2N+all:ylenNHH (I) wherein n is an integer from 1 to 10 and the alkylene group has from 2 to 8 carbon atoms, an alkylphenol and formaldehyde, or the precursors of the Mannich base, the amount of alkaline earth oxide or hydroxide reacted being sufficient to provide more than 1 and less than 1.75 equivalents of alkaline earth metal per equivalent of alkylphenol in the product, and afterwards removing the hydroxylic solvent, characterised in that the sulphurised alkylphenol/salt mixture is reacted with carbon dioxide before it is reacted with the alkaline earth metal oxide or hydroxide.
2. A process according to claim 1 wherein the sulphurised alklphenol has the structural formula:

wherein R2 is an alkyl group containing from 8 to 36 carbon atoms, yl is an integer in the range from 1 to 9 and nl is an integer m the range from 1 to 5.
3. A process according to claim 2 wherein in the sulphurised alkylphenol of formula (II) R is an alkyl group containing from 10 to 30 carbon atoms with the average number of carbon atoms being in the range 10 to 26, y1 is an integer in the range from 1 to 5, averaging over the entire composition in the range from 2 to 4, and n' is an integer from 1 to 3.
4. A process according to either claim 2 or claim 3 wherein R2 in the formula

(II) is predominantly in the para-position.
5. A process according to any one of the preceding claims wherein the carbonated sulphurised alkylphenol/salt mixture (B) contains from 8 to 18 weight percent sulphur.
6. A process according to any one of the previous claims wherein the carbonated sulphurised alkylphenol/salt mixture (B) is produced by reacting a sulphurised alkylphenol/salt mixture with carbon dioxide at elevated temperature.
7. A process according to claim 6 wherein the carbon dioxide is reacted in an amount from 1 to 25% by weight based on the weight of sulphurised alkylphenol/salt mixture.
8. A process according to claim 7 wherein the carbon dioxide is reacted in an amount from 1 to 15% by weight.
9. A process according to any one of claims 6 to 8 wherein the carbon dioxide is added as a solid.
10. A process according to any one of the preceding claims wherein the carbonated mixture (B) is produced by combining alkylphenol, sulphur, calcium oxide or hydroxide and glycol at a temperature in the range 140 to 1500 C, driving off water and hydrogen sulphide, introducing carbon dioxide into the reaction mixture and finally removing the glycol solvent.
11. A process according to any one of the previous claims wherein the Mannich base (C) is prepared from analkylphenol containing from 9 to 25 carbon atoms in the alkyl group.
12. A process according to any one of the previous claims wherein the Mannich base (C) contains from 2 te 10 weight percent nitrogen and has a molecular weight, as determined by csmometry, in the range 600 to 5,000.
13. A process according to any one of the previous claims wherein the alkylene polyamine having the formula (I) is an ethylene polyamine.
14. A process according to claim 13 wherein the ethylene polyamine is diethylene triamine.
15. A process according to claim 13 wherein the ethylene polyamine is ethylene diamine, tetraethylene pentamine or triethylene tetramine.
16. A process according to any one of the previous claims wherein the alkaline earth metal is calcium or barium.
17. A process according to claim 16 wherein the alkaline earth metal hydroxide is calcium hydroxide.
18. A process according to any one of the preceding claims wherein the hydroxylic solvent is ethylene glycol in an amount in the range from 5 to 35 weight percent of the total reaction mixture.
19. A process according to any one of the previous claims wherein the reaction product is obtained by reacting the Mannich base (C) and the carbonated mixture (B) in admixture in an aquivalent ratio (based on phenol) in the range 0.2 to 5:1.
20. A process according to any one of claims 1 to 19 wherein the reaction product is obtained by adding an amount cf alkaline earth metal oxide or hydroxide which provides a total of more than 1 and less than 1.5 equivalents of alkaline earth metal present per equivalent of alkylphenol present in the final product.
21. A process according to any one of the preceding claims wherein an inert solvent, which is a mineral oil of lubricating viscosity, is present in the reaction mixture in an amount in the range of from 3 to 65 weight percent of the total reaction mixture.
22. A process according to any one of the preceding claims wherein the reaction product is obtained by reacting the carbonated sulphurised alkylphenol/salt mixture (B) with the precursors of the Mannich base (C) to form a mixture containing carbonated mixture (B) and Mannich base (C) and thereafter reacting the product with the alkaline earth metal oxide or hydroxide in the presence of the hydroxylic solvent.
23. A process according to claim 22 wherein the carbonated mixture (B) is reacted with the alkylphenol in an equivalent ratio (based on phenol) in the range of from 0.2 to 5:1, the alkylene or polyalkylene polyamine being present in an amount of from 1 to 3 moles and the formaldehyde being present in an amount of 0.75 to 1.25 moles for every 1 to 3 moles of alkylphenol present in the reaction mixture.
24. A process according to either one of claims 22 and 23 wherein reaction is carried out in the presence of a hydrocarbon solvent boiling within the range 50 to 200 C in an amount of from 1 to 50% by weight based on the total weight of the reaction mixture.
25. A process according to any one of the previous claims wherein the reaction product is obtained by reacting the carbonated mixture (B) in admixture with the Mannich base (C) or the precursors thereof in the presence of a carboxylic acid.
26. A process according to claim 25 wherein the carboxylic acid is acetic acid.
27. A process according to any one of the previous claims wherein the product is further reacted with additional amounts of carbon dioxide in the present of the hydroxylic solvent.
28. A process according to claim 27 wherein the additional amount of carbon dioxide added is in the range 1 to 15 percent by weight, based on the total weight of the reaction mixture.
29. A process according to any one of the preceding claims wherein an inert diluent in the form of a hydrocarbonaceous lubricating oil is added to the reaction product after removal of the hydroxylic solvent.
30. A process according to claim 29 wherein undesirable insoluble compounds are filtered off after removal of the hydroxylic solvent.
31. A concentrate composition suitable for formulating finished lubricating oils comprising a minor proportion of a hydrocarbcnacecus lubricating oil and a major proportion of an additive package consisting of, or containing, the hydroxylic solventfree compound produced by the process as claimed in either one of claims 29 or 30.
32. A concentrate composition according to claim 31 wherein the additive package consists of the hydroxylic solvent-free compound in an amount not more than 95% w/w based on the total weight of the composition.
33. A concentrate composition according to claim 32 wherein the additive package contains at least 5% w/w of the hydroxylic solvent-free compound and not more than 90 iO w/w of other additives.
34. A concentrate composition substantially as hereinbefore described with reference to Examples 1 and 2.
35. A finished lubricant composition comprising a major proportion of a lubricant base oil and a minor proportion of the concentrate composition as claimed in claims 31 to 34.