GB1581747A

GB1581747A - Process for the production of a lubricant additive

Info

Publication number: GB1581747A
Application number: GB14295/76A
Authority: GB
Original assignee: Orobis Ltd
Current assignee: Orobis Ltd
Priority date: 1976-04-08
Filing date: 1976-04-08
Publication date: 1980-12-17
Also published as: BE853359R

Description

(54) PROCESS FOR THE PRODUCTION qF A LUBRICANT ADDITIVE (71) We. OROBIS LIMITED, of Devonshire House, Mayfair Place, London, W1, 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 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 produtcts employing polyamines with sulphur-bridged alkyl phenols. U.S. Patent No. 3,454,497 prepares a Mannich base using methyl amine, formaldehyde and alkylphenols for use in lubricating oils. Other patents of interest include U.S. 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 alkylphenol containing at least 4 weight percent sulphur and a Mannich base containing at least 2 weight percent nitrogen and having a molecular weight cf at least 600 and prepared from a C1 to C3 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 copending Application No. 41982/75 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 alkyl phenol 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 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 mole cular weight of at least 600 and prepared from an alkylene diamine or a polyalkylene polyamine having the structural formula: H2N+alkyleneNH+t,H wherein n is an integer from 1 to 10 and the alkylene group has from two to eight carbon atoms, an alkylphenol and formalde hyde, the amount of the 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.

Our copending Application No. 46382/75 describes and claims a compound suitable for use as a lubricating oil additive comprising the reaction product obtained by neutralising with an alkaline earth metal oxide or hydroxide a sulphurised alkyl phenol in admixture with a Mannich base, the neutralisation being carried out 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, and in the substantial absence, as defined, of a hydroxylic solvent.

It has now been found that compounds suitable for use as low-ash basic lubricant additives result when the product obtainable by the reaction of an alkaline earth metal oxide or hydroxide with a sulphurised alkylphenol in admixture with a Mannich base is reacted with carbon dioxide.

Thus according to the present invention there is provided 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: t(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 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 an aver age molecular weight of at least 600 and prepared from an alkylene diamine or a polyalkylene polyamine having the structural formula: H2N2\- 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, thereby forming an intermediate product, the amount of the 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 alkyl phenol in the intermediate product and thereafter reacting the intermediate product with carbon dioxide.

The products of the present invention are complex in nature. Because of the variety of possible reactions which might occur during the formation of the product any attempt to define the composition by means of a general structural formula would be misleading.

The sulphurised alkyl phenol.

The sulphurised alkylphenol preferably has the following structural formula:

wherein R2 is an alkyl group containing from 8 to 26 carbon atoms, more usually from 10 to 30 carbon atoms, the average number of carbon atoms being in the range of about 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 nl is an integer from 1 to 5, more usually from 1 to 3. Their may be small amounts, not more than about 10 weight percent, of sulphurised phenol having yl greater than 9.

The sulphurised alkyl phenol preferably contains from 8 to 18 weight percent sulphur.

The aliphatic hydrocarbon groups designated R2 in the structural formula (II) may be in the ortho-, or para-positions, preferably they will be predominantly in the para-positions.

Since branched chain alkyl groups tend to minimise the amounts of ortho-substituted phenols, branched-chain alkyl groups are preferred. However, it should be realised that to some extent the alkyl groups are in the orthoposition, and ortho-substituted phenols act as chain terminators in the copolymerisation of sulphur and alkylphenol.

Sulphurised alkylphenols (A) and sulphurised alkylphenol/salt mixtures (B) are well known materials for use in lubricating oils.

Their method of preparation is not critical to the process of the invention. The mixtures (B) 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. Sulphur monochloride may also be used to prepare sulphurised alkyl phenols, frequently employing a Frieatel- Crafts catalyst to aid the reaction. Various methods of preparing sulphurised alkylphenols may be found in U.S. Patents Nos. 2,362,289, 2,451,354, 2,744,083 and 3,367,867.

The Mannich base.

The Mannich bases (C) which are employed may be prepared by combining at elevated temperatures, an alkylphenol, formaldehyde and the alkylene diamine or polyalkylene poly amide, preferably ethylene diamine. The alkyl phenol may suitably contain from 4 to 40 carbon atoms, preferably from 9 to 25, even more preferably from 10 to 10 carbon atoms in the alkyl group. The formaldehyde may be added in the form of an aqueous solution (formalin) or in a polymeric form e.g. para formaldehyde. A method for preparing Man nich bases may be found in U.K. Patent No.

1,345,030. U.S. Patent No. 3,454,497 de scribes an additional method for preparing Mannich bases employing primary amines.

The alkylene group of the diamine or poly amine of formula (I) is preferably ethylene, propylene or butylene. The alkylene diamine is preferably ethylene diamine. Polyalkylene polyamines which may be used include diethylene triamine, triethylene tetramine and tetraethylene pentamine. The alkylene diamines and polyalkylene polyamines may be prepared by methods well-known in the art.

The Mannich base (undiluted) will have at least 2 weight percent nitrogen and normally 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 monoor bis-form, the particular form being governed by the ratio of alkylphenol to formaldehyde to amine in the initial 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, even more preferably of calcium.

The hydroxylic solvent.

Ethylene glycol, propylene glycol, butane diols and methanol are examples of suitable hydroxylic solvents. 1,3-; 1,4-; or 1,2-butane diol may be employed. 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 per cent, preferably from 7 to 20 weight percent, of the total reaction mixtures.

Optional additional materials.

In addition to the ethylene glycol, 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 use of the compositions of the invention, mineral oils of lubricating viscosity may be used and the product isolated as a solution in the mineral oil. Normally, the inert diluent may be present in the reaction mix ture, if at all, in amounts from 3 to 65 weight percent, more usually 5 to 50 weight percent of the total reaction mixture.

Conveniently, a small amount of an anti foaming agent or foaming suppressant may be employed. The foam suppressant is suitably present in the reaction mixture in amounts of 1 X 10-5 to 1 X 10-5 weight percent. Foam suppressants are conventional.

Formation of intermediate product.

The intermediate product may be formed by combining either the sulphurised alkylphenol (A) or the mixture (B), the Mannich base (C), the alkaline earth metal oxide or hvdrovide. and the hvdroxylic solvent, e.g. ethylene glycol and heating to an elevated temperature. The Mannich base (C) and either the sulphurised alkyl phenol (A) or the mixture (B) may suitably be combined in an equivalent ratio based on phenol in the range from 0.2 to 5:1, preferably from 0.3 to 3:1.

The amount of alkaline earth metal oxide or hydroxide reacted with the sulphurised alkylphenol (A) or mixture (B) 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.

In the event that a mixture of a sulphurised alkyl phenol and an alkaline earth metal salt of a sulphurised alkyl phenol, i.e. (B), is reacted with the Mannich base (C) the amount of alkaline earth metal oxide or hydroxide actually added in the process of the invention will be less by the amount of alkaline earth metal incorporated during formation of the salt than the amount required to produce the identical amount of alkaline earth metal in the final product when a sulphurised alkyl phenol alone (A) is used. In a preferred method of carrying out the invention either the sulphurised alkylphenol (A) or the mixture (B), the Mannich base (C), the alkaline earth metal oxide or hydroxide and an inert diluent are combined and heated to a tem perature in the range from 90 to 125 C, the hydroxylic solvent is then added and the result ing mixture is thereafter heated at a tempera ture in the range from 125 to 1600C whilst removing water formed in the reaction. The time required for substantially complete removal of the water will usually be from 30 mix'lutes to 3 hours.

Alternatively the Mannich base may be formed from the alkylene diamine or poly allZTlPne nolyamine, the alkylnhenol and form aldehyde in the presence of the sulphurised alKyll,nenol (A) or the mixture (B).

The equivalent ratio (based on phenol) of the sulphurised alkylphenol (A) or the mix ture (B) to the alkylphenol may suitably be in the range from 0.2 to 10:1, preferably 0.2 to 5:1, even more preferably about 1:1. The alkylene diamine or polyalkylene polyamine may suitably be present in an amount of 1 to 3 moles for every 1 to 3 moles of alkyl phenol present. The formaldehyde may suit ably be present in an amount from 0.75 to 1.25 moles for every 1 to 3 moles of alkylphenol present.

Formation of the Mannich base may be effected in the presence of the sulphurised alkylphenol (A) or the mixture (B), by mixing the alkylphenol, the alkylene diamine or polyalkylene polyamine and the formaldehyde and heating them to a temperature sufficient to cause formation of the Mannich base.

Formation of the Mannich base is preferably carried out in the presence of a solvent.

Preferred solvents are the water-immiscible solvents including water-insoluble alcohols (e.g. amyl alcohols) and hydrocarbons. Hydrocarbon solvents boiling in the range 50 to 200"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 of the reaction mixture.

Reaction may suitably be effected at a temperature in the range 50 to 150, preferably 50 to 1300C. 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 1300C. At the end of the reaction the temperature may be raised to about 1500C in order to remove the toluene solvent. The water formed in the reaction co-distils 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 temperatures used. Reaction times of from 1 to 8 hours are easily sufficient.

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

Formation of intermediate product in the presence of carboxylic acid.

According to another aspect of the present invention reaction of the sulphurised alkyl phenol (A) or the mixture (B) and the Mannich base (C) with the alkaline earth metal oxide or hydroxide to form the intermediate product 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 C10 carboxylic acid is preferred. A particularly preferred carboxylic acid is acetic acid. The carboxylic acid may be present in an amount from 0.001 to 0.5 moles, preferably from 0.02 to 0.1 moles per mole of alkylphenol present in the reaction mixture Reaction with carbon dioxide.

Whilst the intermediate 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 intermediate 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 intermediate product mixture by blowing under pressure. Reaction with carbon dioxide is preferably effected at the temperature employed during formation of the intermediate product i.e. 140 to 1500C, although higher temperatures may be employed if desired. The 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.

Removal of hydroxylic solvent.

The process as hereinbefore described produces a solution of the product in a hydroxylic solvent. The presence of a hydroxylic solvent is not desirable in the lubricating compositions in which the product is most advantageously employed. It is therefore preferred to remove the hydroxylic sorvent from the product obtained by reacting the intermediate product with carbon dioxide. In the case where the hydroxylic solvent is ethylene glycol it may conveniently be removed overhead by distillation at a temperature in the range 140 to 2000C and a pressure in the range from 0.01 to 0.8 atmospheres. The time over which ethylene glycol is removed may vary from 30 minutes to 9 hours. For hydroxylic solvents other than ethylene glycol the temperature, pressure and removal time may vary depending on the solvent employed.

The time while 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 rate of 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 1SO"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 1500C.

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 hydocarbonaceous lubricating oils may be employed. The amount of hydro carbonaceous lubricating oil added is prefer ably sufficient to provide a composition containing a minor proportion of lubricating oil and a major proportion of the hydroxylic solvent free product. Whether further diluent is added or not, it is preferred to filter the product after removal of the hydroxylic solvent therefrom to remove any undesirable insoluble compounds therefrom.

The product of the invention.

The product as formed (independent of any diluent) will have alkalinity value (ASTM Test D2896) in mg KOH/g in the range 100 to 450, more usually 175 to 400. The product will 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 2100F, will normally be in the range from 200 to 3,000 SUS, more usually in the range from 500 to 1,500 SUS.

According to another aspect ot 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 product of the process hereinbefore described.

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

Conventional additives may be incorporated into the finished lubricant composition.

The invention will now be illustrated by reference to the following Examples.

In the Examples reference will be made to the Alkalinity Value, which will be abbreviated to AV, as measured by the procedure of ASTM-D2896.

Reference will also be made to a dodecylphenol, which was prepared by alkylating phenol with propylene tetramer.

Example A.

Preparation of sulphurised alkylphenol.

A mixture of 4448 g of a dodecyl-phenol, 206.6 g of CaO and 1280 g of sulphur were heated to 125"cm and then 165 g of ethylene glycol were added. The reaction temperature was raised to 1500C and the pressure reduced to 210 mm Hg and held at that value for 1 hour.

The temperature was then further raised to 195"C and the pressure reduced to 40 mm Hg for a period of 2 hours during which time all the ethylene glycol was removed.

The product was analysed and the following values derived for Ca content, Alkalinity Value (A.V.)* and S content: Ca = 2.41% w/w (theoretical-2.50/0) A.V. = 74.6 mg (KOH/g (theoretical - 70) S = 13.6% w/w * Throughout the specification A.V. represents the alkalinity value as measured by the procedure described in ASTM D2896.

Example B.

Preparation of Mannich base.

A mixture of 448 g of a dodecyl-phenol, 826 g of diethylene triamine, 480 g 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 1600C was then maintained for 1 hour at a pressure of 40 mm Hg.

The product was analysed and the following values obtained for N content, Viscosity210 and A.V.: A.V. = 244 mg KOH/g =5.97 Viscosity210 = 4.6 cS Example 1.

1066 g of a Mannich base (prepared from 1 mole of dodecylphenol, 0.5 mole of diethylene triamine and 1 mole paraformaldehyde using the procedure of Example B), 728 g of a sulphurised alkylphenol (prepared as described in Example A and having a S content - 14.7%) and 628 g of diluent oil were charged to a 5 litre flask and heated to 100"C. 185 g calcium hydroxide and 600 g of ethylene glycol were then added. The temperature was then increased to 125"C and the pressure reduced to 510 mm Hg for a period of 15 mins. The temperature was then increased to 1500C at the same pressure and the reaction mixture held under these conditions for a period of 1 hour whilst the water formed in the reaction was removed.

95 g of CO, representing 3% by weight of the total reaction mixture was then blown into the reaction mixture.

Following injection of the CO2 the pressure was reduced to 50 mm Hg pressure and the temperature increased to 185"C for a period of 15 mins whilst ethylene glycol was removed from the product. On cooling a further 268 g of diluent oil was added and 'the material filtered.

The product was analysed and the results of the analysis are given in the following Table 1.

Example 2.

The same procedure as that described in Example 1 was followed except that 159 g CO2 representing 5% by weight of the total reaction mixture was injected into the reaction mixture.

Example 3.

The procedure of Example 1 was followed except that 87 g CO2 representing 3% by weight of the total reaction mixture was blown into the product after removal of the ethylene glycol and cooling to 1500C.

Comparison Test 1.

The procedure of Example 1 was followed except that no carbon dioxide was added at any stage of the reaction and subsequent workup.

TABLE 1 Analysis of Products

Example No.

Comparison Determination 1 2 3 Test 1 Ca (% b.w.) 4.05 4.19 4.11 4.54 N (% b.w.) 2.18 2.09 2.16 2.13 S (% b.w.) 2.55 2.49 2.87 3.21 A.V. (mgKOH/g) 198 198 206 190 V2l0** (cs) 367 231 512 629 S04 Ash (% b.w.) . 14.04 12.75 13.85 11.1 CO2 (t b.w.) 0.97 1.88 0.63 - ** V2,0 is the viscosity measured at 2100F.

Examination of the above Table shows that the products cf Examples 1 and 2 wherein the neutralised product is reacted with carbon dioxide in the presence of ethylene glycol have considerably lower viscosities than the product from the Comparison Test 1 in which no carbon dioxide was added. Furthermore the product of Example 3 wherein the carbon dioxide was reacted with the neutralized product after removal of ethylene glycol has a lower viscosity than the product of the Comparison Test 1 though not so low as the products of Examples 1 and 2. The lower viscosities of the products of Examples 1 and 2 are achieved at marginally higher ash contents and marginally lower sulphur contents than the product cf the Comparison Test 1, though the values for these parameters are comparable with those for the product of Example 3. All other values for the contents of Ca and N and the acid value are comparable.

Example 4.

A mixture of 371 g of sulphurised alkylphenol (= 1 mole), 278 g of dodecylphenol (= 1 mole), 500 mls of toluene, 90 g diethylene triamine and 50 g paraformaldehyde was heated to remove the water of reaction.

The mixture was then vacuum stripped to remove all the toluene solvent, the maximum temperature being 1500C and the pressure 40 mm Hg.

To the reaction product was added 275 g diluent oil, 110 g Ca(OH), and 300 ml ethylene glycol. This mixture was heated to 125"C for 15 minutes and then the temperature was raised to 1500C for 1 hour.

The neutralised product was carbonated by blowing in 40 g CO2 and was then vacuum stripped to remove the ethylene glycol at a temperature up to 1900C and a pressure of 30 mm Hg.

To the carbonated neutralised product was added 50 g diluent oil, after which the product was cooled and filtered.

Product analysis: A.V. = 258 mg KOH/g Vise,, = 1063 cS %N = 2.85 % sulphated ash = 19.5 Example 5.

The procedure of Example 4 was repeated.

The initial reaction mixture was: 371 g sulphurised alkylphenol 278 g dodecylphenol 110 g diethylene triamine 60 g paraformaldehyde 500 cc toluene.

To the reaction product was added: 80 g Ca(OH)2 150 g 100 Solvent Neutral oil 200 g ethylene glycol.

To the neutralised product was added 27 g CO2 and 200 g diluent oil was added to the

Comparison Test 2.

Example 7 was repeated except that neither carbon dioxide or acetic acid were added.

Example 10.

Example 7 was repeated except that no acetic acid was added.

Comparison Test 3.

Example 7 was repeated except that no carbon dioxide was added.

TABLE 2

A.V. V210O %N %Ca Example mg KOH/g cS Comparison Test 2 216 594 2.49 4.11 Example 10 207 423 2.50 4.15 Comparison Test 3 216 577 2.42 3.85 Example 7 205 259 2.30 3.96 Example 8 198 321 2.65 4.00 Example 9 204 256 2.46 4.06 Examples A to D and Comparison Tests 1 to 3 are not Examples according to the invention.

Example 11.

Compatibility Tests.

The products of Examples 1 to 3 and the Comparison Test 1 were blended with BP (Registered Trade Mark) HV150 lubricating oil to an A.V. of 110 and allowed to stand.

After 21 days the blends remained compatible.

Example 12.

A. Preparation of Sulphurised Alkylphenol.

1 mole dodecylphenol, 0.25 mole Ca(OH)2 and 2.5 mole sulphur were charged to a reaction vessel and the temperature raised to 125"C. Ethylene glycol [equal to 0.5 X weight of Ca(OH)2] was added and the temperature raised to 1500C. Vacuum was applied and the pressure set at 500 mm Hg fo; for~l~hour. The reaction mixture was then vacuum stripped at 195"C (base temperature) under maximum vacuum for 2 hours, after which it was cooled and diluted with lube oil.

B. Preparation of Mannich Base.

1 mole dodecylDhenol and 0.5 mole diethylene triamine (DETA) were charged to a flask. 1 mole paraformaldehyde was slowly added causing an exothermic reaction. The temperature was slowly raised to 1300C at which value it was held for 2 hours whilst water was removed via a Dean and Stark trap. The reaction mixture was then vacuum stripped to remove residual water and solvent and then diluted with oil.

C. Preparation of Product.

0.6 moles of the Mannich Base B, 0.4 moles of the sulphurised alkylphenol and lube oil were mixed in a reaction flask which was heated to 1250C. 1 mole of lime and ethylene glvcol [3.25 X weight of limel were added.

The pressure was then reduced to 500 mm Hg pressure and the temperature maintained at 1250C for 15 minutes. The temperature was then raised to 150dC for 1 hour.

5% by weight, based on the weight of the reaction mixture. of solid carbon dioxide was then added whilst maintaining the reaction temperature at 1500C and the pressure at atmospheric.

The reaction product was vacuum stripped to 50 mm Hg pressure at 1850C base temperature, cooled and diluted with lube oil to give 33% oil in finished product.

Finally the product was filtered.

The analysis of the product in terms of its A.V., Vis210, %Ca, %N and %S is given in Table 3.

Example 13.

Example 12 was repeated using the quantities of reactants shown in Table 3.

Example 14.

Examples 12 was repeated using the quantities of reactants shown in Table 3.

Example 15.

Example 12 was repeated using the quantities of reactants shown in Table 3.

Example 16.

Example 12 was repeated using the quantities of reactants shown in Table 3.

Example 17.

Example 12 was repeated using the quantities of reactants shown in Table 3.

Example 18.

Engine Evaluation.

Solutions of the products of Examples 12 to 17 were dissolved in a lubricant base oil, as was a conventional prior art additive (calcium phenate) to an alkalinity value of 25 mg KOH/g. The solutions were then evaluated in the Ring Belt Merit test in a Petter (Regis tered Trade Mark) AVI engine running under standard conditions but modified to run on residual fuel containing approximately 2.8% sulphur.

The oil containing calcium phenate was run as a reference before and after the candidate oil, and the candidate oil judged by a figure of merit (F.O.M.) in which 1.0 represents the value for the reference oil. Since the accuracy of the test is + 0.1 an F.O.M. for a candidate of 0.9 to 1.1 is taken as an indication of a comparable degree of piston clean liness.

The Ring Belt Merit (R.B.M.) derived from the average ratings of the - four lands and three grooves on the piston was also observed.

The results of the R.B.M. and F.O.M. observations are given in Table 3.

TABLE 3

Mannich Base Product Analysis Engine Test Data Moles Moles % by A.V.

Example dodecyl- Moles Moles Mannich Moles Moles weight mg KOH % Ca % N Vis210 % S R.B.M. F.O.M.

No. phenol DETA pHCHO Base SAP lime CO2 /g cS 12 1 0.5 1 0.6 0.4 1 5 198 4.19 2.09 231 2.49 5.7 0.78 13 1 0.5 1 0.6 0.4 1 3 198 4.05 2.18 367 2.55 6.3 0.88 14 1 0.5 1 0.6 0.4 1 3 190 4.10 2.27 232 2.48 7.1 1.15 15 1 0.5 0.75 0.6 0.4 1 3 200 3.90 2.14 198 2.56 7.1 0.90 16 1 0.5 0.75 0.6 0.4 1 3 187 3.92 2.10 111 2.48 6.3 0.80 17 1 0.5 0.75 0.6 0.4 1 5 187 4.06 2.28 146 2.47 7.3 0.80 In every Example the sulphurised alkylphenol (SAP) was formed by reacting 1 mole dodecyl-phenol with 0.25 moles Ca(OH)2 and 2.5 moles sulphur.

Claims

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 either: (A) a sulphurised alkylphenol containing from 4 to 20 weight percent sulphur or l(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$alkylene-NHH (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.

2. A process according to claim 1 wherein the sulphurised alkyl phenol 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 in the range from 1 to 5.

3. A process according to claim 2 wherein in the formula (II) R2 is an alkyl group containing from 10 to 30 carbon atoms, the average number of carbon atoms being in the range of 10 to 26, yl is an integer in the range from 1 to 5, averaging over the entire composition from 2 to 4, and nl is an integer from 1 to 3.

4. A process according to either one of claims 2 and 3 wherein the substituent R2 in the formula (II) is predominantly in the paraposition.

5. A process according to any one of the preceding claims wherein the Mannich base (C) contains from 2 to 10 weight percent nitrogen and has an average molecular weight, as determined by osmometry, not exceeding 5,000.

6. A process according to any one of the preceding claims wherein the alkylene group of the diamine or polyamine of formula (I) is ethylene, propylene or butylene.

7. A process according to claim 6 wherein the diamine is ethylene diamine.

8. A process according to claim 6 wherein the polyamine is diethylene triamine, triethylene tetramine or tetraethylene pentamine.

9. A process according to any one of the preceding claims wherein the alkaline earth metal is calcium or barium.

10. A process according to any one of the preceding claims wherein the hydroxylic solvent is ethylene glycol, propylene glycol, a butanediol or methanol.

11. A process according to claim 10 wherein the hydroxylic solvent is ethylene glycol in an amount from 5 to 35 weight percent of the total reaction mixture.

12. A process according to any one of the preceding claims wherein an inert diluent is present in an amount from 5 to 50 weight percent of the total reaction mixture.

13. A process according to any one of the preceding claims wherein the Mannich base (C) and either the sulphurised alkylphenol (A) or the mixture (B) are combined in an equivalent ratio based on phenol in the range from 0.2 to 5:1.

14. A process according to any one of the preceding claims wherein either the sulphurised alkylphenol (A) or the mixture (B), the Mannich base (C), the alkaline earth metal oxide or hydroxide and an inert diluent are combined and heated to a temperature in the range from 90 to 1250C, the hydroxylic solvent is then added and the resulting mixture is thereafter heated at a temperature in the range from 125 to 1600C thereby removing water formed in the reaction.

15. A process according to any one of claims 1 to 12 wherein the Mannich base is formed from the alkylene diamine or polyalkylene polyamine, the alkylphenol and formaldehyde in the presence of the sulphurised alkylphenol (A) or the mixture (B).

16. A process according to claim 15 wherein the equivalent ratio (based on phenol) of the sulphurised alkylphenol (A) or the mixture (B) to alkylphenol is in the range from 0.2 to 5:1, the alkylene diamine or polyalkylene polyamine is present in an amount from 1 to 3 moles and the formaldehyde is present in an amount from 0.75 to 1.25 moles for every 1 to 3 moles of alkylphenol.

17. A process according to either one of claims 15 or 16 wherein the Mannich base is formed in the presence of a hydrocarbon sol vent boiling within the range 50 to 2000C in an amount of 1 to 50% by weight based on the total weight of the reaction mixture.

18. A process according to claim 17 wherein the solvent is benzene, toluene or xylene.

19. A process according to any one of claims 15 to 18 wherein the Mannich base is formed at a temperature in the range 50 to 130"C.

20. A process according to any one of the preceding claims wherein reaction of the sulphurised alkylphenol (A) or the mixture (B) and the Mannich base (C) with the alkaline earth metal oxide or hydroxide to form the intermediate product is effected in the presence of a carboxylic acid in an amount from 0.001 to 0.5 moles per mole of alkylphenol present in the reaction mixture.

21. A process according to claim 20 wherein the carboxylic acid is a C, to C10 carboxylic acid.

22. A process according to claim 21 wherein the carboxylic acid is acetic acid.

23. A process according to any one of the preceding claims wherein the intermediate product is reacted with carbon dioxide in the presence of the hydroxylic solvent.

24. A process according to claim 23 wherein the carbon dioxide is blown under pressure into the intermediate product at the temperature employed during its formation.

25. A process according to either one of claims 23 or 24 wherein the amount of carbon dioxide added is in the range 1 to 15 percent by weight, based on the total weight of the reaction mixture.

26. A process according to any one of claims 23 to 25 wherein the hvdroxylic solvent is removed from the product obtained by reacting the intermediate product with carbon dioxide.

27. A process according to claim 26 wherein the hydroxylic solvent is ethylene glycol which is removed overhead by distillation at a temperature in the range 140 to 200"C and a pressure in the range from 0.01 to 0.8 atmospheres.

28. A process according to claim 27 wherein the product is cooled after removal of the ethylene glycol and an inert diluent is added to the cooled product.

29. A process according to claim 28 wherein the product is cooled to a temperature above 1500C before addition of the inert diluent.

30. A process according to either one of claims 28 or 29 wherein the inert diluent is a hydrocarbonaceous lubricating oil.

31. A process according to any one of claims 26 to 30 wherein the product is filtered after removal of the hydroxylic solvent therefrom to remove undesirable insoluble compounds therefrom.

32. A process for the production of a product suitable for use as a lubricating oil additive substantially as hereinbefore described with reference to Examples 1 to 17.

33. A product suitable for use as a lubricating oil additive whenever produced by a process as claimed in any one of the preceding claims.

34. A finished lubricant composition comprising a major proportion of a lubricant base oil and a minor proportion of the product produced by a process as claimed in any one of claims 1 to 32.