CA1069501A

CA1069501A - Lubricant additive formed by neutralisation of a sulphurised alkyl phenol and a mannich base

Info

Publication number: CA1069501A
Application number: CA263,510A
Authority: CA
Inventors: John Crawford
Original assignee: Orobis Ltd
Current assignee: Orobis Ltd
Priority date: 1976-10-15
Filing date: 1976-10-15
Publication date: 1980-01-08

Abstract

ABSTRACT OF THE DISCLOSURE
A lubricant additive comprising the reaction product obtained by neutralising a sulphurised alkyl phenol containing at least 4 wt % sulphur and a Mannich base containing at least 2 wt % nitrogen with an alkaline earth metal oxide or hydroxide, the Mannich base having a molecular wt of at least 600 and being prepared from an alkylene or polyalkylene polyamine, alkyl phenol and formaldehyde, the neutralisation being carried out at elevated temperature and in the presence of a hydroxylic solvent.

Description

OL

This invention relates to a compound suitable for-use as a lubricating oil additive.
Lubricating oils used under the ~evere conditions of diesel engines are highly compounded ~o as to provide neutralization of acid~ derived from the sulphur in the fuel and oxidation of hydrocRrbons, both of the fuel and oil; dispersancy 80 as to maintain ~ludge-forming precursors dispersed in the oil; improved wear protection and oiliness properties; as well as enchancing other attributes of the oil. In addition to the requirements normally attendant to a diesel lubricating oil, those oils which find use in railway diesel engines have the additional factor of not being corroaive or reactive to ~ilver. Silver bearings are used in a preponderant number of diesel engines today.
The de~irability of having a single additive providing multifunctional properties i9 evident in the efficiency and economies in the manufacturing and using of a single additive as compared to a plurality of additives. ~owever, 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 eDhance depc3it formation. Therefore, in designing any particular additive, it is essential not only that it fulfill the function(s) for which it has been designed, but that it be stable under the conditions of u9e or degrade slowly to materiQls 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 sulphurized alkylphenols and ~annich ba~es have been employed in lubricating oils~
U.S. Patent Nos., 2,459,114 and 2,459,116 teach the preparation of Mannich products employing polyamines with sulphur-bridged alkyl 3 phenol~. U.S. Patent No. 3,454,497 prepares a ~annich base using !

- 2 -.... . . . . . . .
.. .:
: . . .. . .

methyl amine, formaldehyde and alkylphenols for use i~ lubricating oils. Other patent~ of interest include U.S. Patent ~08. 2,810,697, ~i,372,118, 3,429,812, 3,472,773, 2,527,279, 2,763,616, ~9368,972, 2,410,911, 2,962,442, 3,413,347 and 3,340,190.
British patent specificatio~ ~o. 1,352,760 describes and claims a dispersant detergent suitable for use as a lubricating oil additive, comprising the reaction product obtainable by the neutrali3ation with an alkaline earth metal oxide or hydroxide of a sulphuri~ed slkyl phenol containing at least 4 weight per cent sulphur and a Nannich base containing at least 2 weight percent nitrogen and having a molecular weight of at lea~t 600 and prepared from a C1 to C3 alkylamine, an alkylphenol and formaldehyde, ths neutralisation being carried out in the presence of a hydroxylic solvent aud at an elevated temperature 80 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.
It haR now been found that newphenates having a lower ash content for the-sams aegree of alkalinity reserve result when the C1 to C3 aIkyl-amine u~ed in the preparation of the Nannich base i5 replaced by an alkylene or polyalkylene polyamine.
Thus according to the present invention there is provided a compound suitable for u~e as a lubricating oil additive comprising the reaction product obtained by neutralising with an alkaline earth metal oxide or hydroxide a sulphurised alkyl phenol containing at least 4 weight per cent sulphur in admixture with a Nannich base containing at least 2 ~eight per cent nitrogen and having a molecular weight of at least 600 and prepared from an alkylene or poly~lkylene polyamine having the structural formula:-~2~ ~ alkylene ~

~Otii~Q:I
wherein n iQ an integer from 1 to 10 and the alkylene group ha~
from two to eight carbon atoms, an aIkyl phenol Pnd formaldehyde, the neutralisation being carried out in the pre~ence of a hydro~ylic solvent and at an elevated temperature 80 that molecular bonds are formed between the Mannich base and the sulphurised alkyl phenol in addition to the bridging bond~ created by the alkaline earth metal.
The preferred alkylene polyamines are the ethylene polyamine~
wherein the alkylene group has two carbon atoms. A preferred ethylene polyamine is ethylene diP~ne. Other polyalkylene poly-amine3 which may be used include diethylene triamine, tetraethylene pentamine and triethylene tetramine. Further alkylene polyamines which may be used include, for esample, propylene polyamines and butylene polyamines. The alkylene polyamines may be prepared by methods well-known in the art.
The products of the present invention are comples in nature.
3ecause of the variety of the possible reactions which might occur during the formation of the product any attempt to defins the composition by means of a general structural formula would be meaningless.
~he compounds of this i~vention may advantageously be prepared by combining the ~annich base and sulphurised alkyl phenol 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 above reactants are included an alkaline earth metal oYide or hydroxide, preferably hydroxide, and a hydroxylic solvent, usually ethylene glycol.
The amount of alkaline earth metal base added will depend on the method of preparation of the sulphurised alkylphenol. To the degree that an aLkaline earth metal base was employed during the preparation of the sulphurised alkylphenol, the added a~ount of :. ,, , :
: ; , :: . . :.,;; , .

~0~95~1 alkaline earth metal base may provide a total of up to one equivalent of alkaline earth metal present per equivalent of alkylphenol pre~ent in the final product. ~lternatively an excess of the alkaline earth metal base may be employed usually not e~ceeding 1.75 equivalents, and more u~ually not e~ceeding 1.5 equivalents of alkaline earth metal per equivalent of alkyl phenol present in the final product.
The amount of the hydro~ylic solvent will vary with the particular solvent employed. Ethylene glycol, prop~lene glycol, butane diols and methanol are examples of suitable sQlvents. 1,3-;
- 10 1,4 ; or 1,2-butane diol may be employed. Since ethylene glycol i8 the preferred solvent, only its use will be discussed in detP 1.
~he amount of ethylene glycol employed may normally be from about 5 to 35 weight percent, preferably from about 7 to 20 weight percent, of the total reaction mi~ture.
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 mi~ture, and enchancing the ease of isolation of the product.
In ~iew 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. ~ormally, the inert dilue~t may be present in the reaction mi~ture, if at all, in amounts of from 3 to 65 weight percent, more usually 5 to 50 weight percent of the total reaction mi~ture.
Conveniently, a small amount of an anti-foaming agent or foaming suppressant may be employed. The foam ~uppressant may be present in the reaction mi~ture in amounts of 1 ~ 10 3 to - 1 x 10 5 weight percent. ~oam suppressants are conventional and need not be e~emplified here.
~he various reactants will now be considered. ~he first and . .
~ s r~ ~

5~1 simplest reactant is tha aIkaline earth metal o~ide or hydroside.
These are preferably calcium and barium, even more preferably calcium. With calcium normally calcium hydroxide will be employed.
Sulphuri~ed alkylphenols are well known material-~ for u~e in lubricating oils. The method of preparation of the sulphurised aLkylphenols is not critical to this invention.
The sulphurised alkylphenols may,for the most part and preferably at least 90 percent, ha~e the following formula:
/ a~ \ OH

(5)=1 ~

~herein R2 19 an alkyl group containing from 8 to 36 carbon atoms, more u~uslly from lO to 30 carbon atoms with the average number of carbon atoms being in the range of about lO to 26, y1 i9 an integer in the range fro~ l to 9, more u3ually from l to 5, averaging over the entire composition in the range from about 2 to 4, and n1 is an integer of from l to 5, more usually from 1 to ~. There may be small amounts not more than about lO weight percent of sulphurised phenol having y1 greater than 9.
The sulphurised alkylphenol may have at least about 4 weight percent sulphur and preferably not more than 20 weight percent sulphur, more usually from about 8 to 18 weight percent sulphur.
Preferably, there will be at least 0.5, and not more than about 16 weight percent sulphur, based on the weight of sulphurised alkyl phenol composition pres2nt which is not involved in bridging or i5 involved in bridges having at least 3 sulphur atoms. Usually, there will be present about l to 9 weight percent sulphur, based on the weight of ~ulphuri~ed aIkylphenol composition which i9 in a form suitable for a bridging reaction.
The aliphatic hydrocarbon groups de~ignated ~2 in the 3tructural formula (II) may be in the ortho-, or ~ara-positions~ preferably they will be predominantly in the ~ara-po~ltionsO Since branched ch~ alkyl groups tend to minimise the amount~ of ortho-substituted phenols, branched-chain aLkyl groups are preferred. ~owever, it should be r2alised that to some e~tent the 8Ikyl groupq are i~ the ortho po~ition, and ortho-substituted phenol~ act as chain terminators in the copolymerisation of sulphur and alkyl phenol.
The sulphurised alkylphenol may be prepared by combining aIkyl phenol, ~ulphur, calcium oxide, or calcium hydro~ide and glycol at an elevated temperature, driving off the water and hydro6en sulphide, followed by isolation of the sulphurised alkylphenol. See for example US Patent ~o. 2,989,4~. Sulphur monochloride may also be used to prepare ~ulphurised alkylphenols, frequently employing a Friedel-Crafts catalyst to aid the reaction. Various methods of preparing sulphurised alkylphenols may be f~nd in US patent Nos.
2,362,289, 2,451,354, 2,744,083, and 3,367,8~7.
The ~lannich bases which are employed may be prepared by combining at elevated temperatures, an alkylphenol, formaldehyde and the alkylene or polyaIkylene polyamine, preferably ethylene diamine. The aIkylphenol may suitably contain from 4 to 40 carbon atoms, preferably from 9 to 25, even more preferably from lO to 14 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. paraformaldehyde. A method for preparing the ~annich bases may be found in U.K. application No. 2531b/71 (Serial No. 1,345,030).
30 U.S. Patent No. 3,454,497 describes an additional method for S~

preparing Mannich bases employing primary amine9-~ he Mannich base (undiluted) will preferably have at lea~t 2 weight percent nitrogen and normally not more than about 10 w~eight percent nitrogen. The average molecular weight~ as ~etermined by osmometry, i9 at least ~00, more u~ually at least 700~ and normally not esceeding about 5,000.
The Mannich base may be in the mono- or bis-form, the particular form being governed by the ratio of alkyl phenol to amine material in the initial preparative mixture.
The reaction may be conveniently carried out by combining the sulphurised aIkylphenol, the Ma~nich base, the aIkaline earth metal oside or hydro~ide, and the hydroxylic solvent e.g. ethylene glycol~ ~8 already indicated, an inert diluent may also be preQent.
Preferably, prior to the addltion of the ethylene glycol, the mi~ture i~ heated to at least 90C, but below the temperature at which the neutralisation is to be carried out. Aftsr addition of the ethylene glycol, the temperature may be raised 90 as to distil water overhead, removing the water of reaction. ~sually the temperature during removal of water will range from 125 to 160C. The time required for the removal of water will usually be from about 30 mLnutes to

3 hours.
Whilst incorporation of a hydro~ylic solvent facilitates the production of the compound its presence is not desirable in the lubricating compositions in which the compound is most advantag-eously employed. It is therefore preferred to remove the hydro~ylic solvent after formation of the compound. This is most con~eniently achieved by raiQing the temperature to less than 200C after removing the water of reaction. The temperature during removal of ethylene glycol may range from 140 to 200, preferably from 1~0 to 180C.
The pressure may be reduced to permit the distillation of 3~
glycol. The actual value of the pressure employed will vary cLepending on the temperature and rate of distillation required, but will generally be in the range from about 0.01 to 0.8 atmospheres.
The time over which ethylene glycol is removed may be from about 30 minutes to 9 hours. For hydro~ylic solvents other than ethylene glycol the temperature, pressure and time for removal may vary depending on the solvent employed.
The time to accomplish the complete reaction, that is from the initial removal of water to substantially complete removal of ethylene glycol may vary from about 1 hour to 6 hour~. ~he time while not a ~ritical factor should not be unduly prot~acted, and will depend on the capacity of the e~uipment, 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 mi ture may be cooled. At this stage it i8 preferred to add an inert diluent. Depending on the presence and amount of inert diluent already in the reaction mi~ture, the temperature i9 preferably maintained above about 150UC prior to sufficient dilution with a convenient diluent. The mi~ture can become extremely viscous, and solution into a diluent is difficult below a temperature of about 150C. 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 variou~ hydrocarbonaceous lubricating oils may be employed. Whether further diluent is added or not, it is preferred to filter off any undesirable in~oluble compounds.
The product as formed (independent of any cliluent) will have aIkalinity value (ASTN ~est - D2896) in mg. K0~/g. in the range 100 to 450, more usually about 175 to 400. The product will _ g _ 6'~01 provide in elemental analysis from about 2 to 12, more usually from about 3 to 7, weight percent alkaline earth metal, at lea~t about 0.1 to 5, more usually from about 0.5 to 4, weight percent nitrogen, and from about 0.8 to 10, more usually from about 1 to 8, weight percent sulphur. In a 100 neutral oil, (100 being the viscosity at 100F in SUS) at an alkaline earth metal concentration of 0.88 molar (3.5 weight percent for Ca), the vi~cosit~ at 210~, will normally be in the range of about 200 to 3,000 S~S, more usually in the range of 500 to 1,500 S~S.
~9 diluted the product is ready to be employed as a concentrate for formulating finishsd lubricating oilQ or may have added thereto other conventional additive compoundq.
~he i~vention therefore additionally provides a concentrate composition suitable for formulating finished lubricating oils comprising a minor proportion of a hydrocarbonaceous 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 consi~t entirely of the hydro~ylic solvent-free compound as hereinbefore described in an amount up to 95~o w/w based on the total weight of the concentrate composition.
Alternatively the additive package may contain at lea~t 5~o w/w of the hydro~ylic solvent-free compound as hereinbefore described and up to 90~ w/~ of other additives, based on the total weight of the concentrate compo~ition. The other additives may be, for e~ample~ VI improvers, pour-point depressants, anti-foa~ agents, oxidation inhibitors, e~treme pressure agents or any of the additives oommonly used in lubricating oil formulations.
According to another aspect of the present invention there is provided a finished lubricant composition comprising a major proportion . . - .. i: .

~Q~9~

of a lubricant bass oil and a manor proportion of the concentrate composition as hereinbefore de3cribed.
The lubricant base oil mag be a mineral oil derived from petroleum or a synthetic oil based, for example, on esters.
Conventional 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 in~ention ha~e similar alk~linity reserves to conventional additlves their ash content is very much lower.
The invention will now be illustrated with reference to the following Examples.
Preparation of sulphurised alkyl phenol Ex2mple A
To a reaction vessel was added 2240g of a C12-alkyl phenol (prepared by alkylating phenol with propylene tetramer), 103g of CaO and 642g of sulphur. The mixture was heated to 125C and 81.5g of ethylene glycol slowly added. The temperature waY then raised to 150C at a pressure of 550mm ~g. Water wa~ removed over a period of 1 hour and then the temperature further raised to 195C
under full vacuum (50mm ~g pressure) for 2 hours. The product was analysed and had the following composition:-S = 14.4%
Ca = 2.8~
Alkalinity Value (AV) = 72.2 mg KOH/g E~ample ~
To a reaction vessel was added 2224g of a C12-alkyl phenol,**
144g of Ca(OE)2 and 642g of S. The subsequent procedure was identical to that described in Example A.
The analysis of the product was as followss-~ ~g5~L

Ca = 2.86%
S = 15.0%
AV* = 81.2 mg Ko~jg Ecample C
To a reaction vessel wa~ added 4448g of a C12-alkyl phenol,**
296g Ca(OH) and 1280g sulphur. The subsequent pro¢edure wa~
identical to that described in Example A except that 165g ethylene glycol was added. Furthermore after heating at 195C and 50 mm ~g pressure the product was diluted with 2108g lOOS~ lube oil and filtered.
The analysis of the product was as follows:-AV* = 57.7 mg KO~/~
Ca = 1.99%
S = 11.06~
~iscosity 210F = 99.2 ca Example D
To a reaction vessel was added 1960g of a C12-alkyl phenol,**
98g CaO and 560g sulphur. The subsequent procedure was identical to that describ0d in Example A except that 77g ethylene glycol was slo~ly added.
The analy~is of the product was as follows:-S = 16.6%
Ca = 2.59 AV* = 66.3 mg EO~/g Preparation of Mannich Base ~xamDle E
To a reaction vessel was ¢harged 2240g of ~ C12-alkyl phenol,**
240~ ethylene diamine and 500ml. toluene. To the mixture was added 678g of aqueous formaldehyde solution over a period of 1 hour. The temperature wa~ raised to 80C and was held at this value for 1 hour.

- ,; . ., . ;, . .,.. .:.: :: :: :: : :
: ; ; , .,;:; , : : ,:, - . ,: . .,. . . : : .: ~

~69S~l By raising the temperature to 150C all the water was di~tilled off.
The product mixture was cooled and wa~hed with water to remove ~nreacted ethylene diamine. The mixture was then stripped to remove water and filtered - 110C for 2 hours, The product was analysed for nitrogen content and its alkalinity value (A.V.) and viscosity at 210F measured. ~he following results were obtained:-A.V. = 158.4 mg KOH/g Nitrogen content = 3.87%
Viscosity 210F = 726c~
Example F
4656g of C12-alkyl phenol,** B24g of diethylene triamine and 1250 ml of toluene were added to a reaction vessel. Over a period of 1 hour 480g of para-formaldehyde was added to the reaction vessel causing an exothermic reaction. The reaction mixture wa~ heated to a final base temperature of 140C during which time the water produced during the reaction was removed by azeotropic distillation.
~he product was then washed with 1 litre of water which was removed by azeotroplc distillation. Finally the product was filtered.
A.V.** = 225 mg KOH/g ~ content = 5.81%
Visco6ity 210~ = 390 cs Example G
2160g C12-alkyl phenol,** 584g triethylene tetramine and 500ml.
toluene were charged to a reaction vessel. Over a period of 1 hour 615g of aqueous formaldehyde solution was added to the reaction vessel. ~hereafter the procedure described in Example D was followed. ~he product obtained was analysed as follows:-A.V. = 279 mg KOH/g 3 N = 7.38~

t~V~
.

Viscosity 210~ = 406 Xample ~
4620g of a C12-alkyl phenol,** 858g diethylene triamine ana 990g 100 SN lube oil were charged to a reaction vessel. 375g paraformaldehyde was then added slowly to the mixture. The mixture was heated to 120 to 125C and held at that temperature for 2 hours during which the water produced in the reaction wa~ removed by distillation. To ensure removal of all the water the product was vacuum stripped at 20 mm ~g pressure and 130C base temperature for 30 min8. On cooling a further 980g of 100 S~ lube oil was added.
The product was analy~ed as follows:-.V.*~ = 179.4 mg ~O~/g = 4.26~
Viscosity 210F = 23.8 C8 Pre~aration of final product E~pl~
261g of the Mannich ~ase product from Example E, 748g of the sulphurised alkyl phenol product from Exampls D and 83.5g of lube oil (lOOS~) were charged to a reaction vessel and the temperature raised to 90C when 18.5g of Ca(OH)2 and 60.3g of ethylene glycol were added. The temperature was raised to 150C and the pressure reduced to 50 mm ~g over a period of 2 hours. ~inally the temperature was raised to 185C for a period of 15 minutes. 50.4g of lube oil was added and the product filtered off. The product was analysed for calcium, sulphur and nitrogen content and the alkalinity value (A~) measured. The following analysis was obtained:-Ca = 2.18%
S = 2.10%

N = 1.61%

:, ~ : . . , ,~,. .. .

50~

A.V. = 195.4 mg EO~/g I~oam~le 2 261g of the Mannich ~a e product from Example E, 74.8 of the l~ulphurised alkyl phenol product from ~xample D and 83.5g of lube -oil (1005N) were charged to a reaction vessel and the procedure described in Example 1 followed ex¢ept that 37g Ca(OH~2 and 120g ethylene glycol were added.
The analy~is of the product was as follows:-- Ca = 4.29%
s = 1~14~o - 2.21%
A.V. = 195.4 mg KO~/g Examp19 ~
284g of the Mannich Base product from Example G, 7406g of the sulphurised alkyl phenol product fro- Example A and 125.5g of lube oil (lOOSN) were charged to a r~action ves3el and the procedure described in Example 1 repeated except that 37g of Ca(0~)2 and 120g ethylene glycol were added.
The analysis of the product was as follows:-Ca = 3.84%
S = 1.73%
- N = 3.9%
A.V. = 259 mg EOH/g Vi~cosity 210F = 2474cs Example 4 lOOOg of the Mannich ~ase product from Example F, 745g of the sulphurised alkyl phenol product from Example A and 611g of lOOS~
lube oil were charged to a reaction vessel and heated to 90C when lS5g (Ca(OH)2 and 601g ethylene glycol were added. The temperature 30 was raised to 125C and held at this value for 15 mins. The - .. : . . ; - . :: : ,, .: . :

pre~ure was then reduced to 500 mm ~g whilst maintaining the temperature at 125C and the reaction mixture held under the~e conditions or a further 15 mins. At the same pressure the 1;emperature was raised to 150C and held at this value for 1 hour.
The product was then vacuum stripped at 185C and 50 mm Eg pres3ure for 15 mins. Finally the product was cooled, 88g lOOS~
lube oil added and filtered.
~ he analy~is of the product is given in Table 1 Example 2660g of the Mannich Base product fro~ Example F, 1865g of the sulphurised alkyl phsnol from Example A and 1583g 1005~ lube oil were charged to a reaction vessel and the procedure de~cribed in Example 4 followed except that 1505g ethylene glycol, 463g Ca(0~)2 and a further 226g lOOS~ lube oil were added.
The analysis of the product is given in Table 1.
Example 6 1171g of the Mannich Ba~e product from Example F, 552g of the sulphurised alkyl phenol product from Example A and 603g lOOS~
lubs oil were ch~rged to a reaction ves~el and the procedure described in Example 4 followed except that 601g ethylene glycol, 185g Ca(OH)2 and a further 86g lOOSN lube oil were added.
The analysis of the product is given in Table 1.
Example 7 1029g of the Mannich Base product from Example F, 752g of the sulphuri~ed alkyl phenol product from Example ~ and 623g lOOSN
lube oil were charged to a reaction vessel and the procedure described in Example 4 followed except that 600g ethylene glycol, 185g calcium hydroxide and a further 267g lOOSN lube oil were added.
The analysis of the product is given in Table 1.

5~el Example 8 -1440g of the Mannich ~ase product from Example ~, 995g of the ~ulphurised alkyl phenol product of Example C and 611g of lOOSN lube oil were charged to a reaction vessel and heated to 120C when 185g Ca(0~)2 and 600g ethylene glycol were added. The procedure described in Example 4 was then followed except that a further 265g lOOS~ lube oil was added.
The analysis of the product is given in Table 1.
Table 1 Analysis_of ~roducts _ , _ Product of _ alysis_ ~
E~ample AV Y210FCa(%) N(~o) 5(~) . . _ _

4 205 13334.29 2.31 2.83 201 27204.15 2.47 2.95 6 236 21644.35 2.64 2047 7 191 5964.25 2.14 2.78 8 199 3314.og 2-3B 2.75 .
Example 9 En~ine Evaluation Solutions of the products of Examples 4, 5, 6, 7 and 8 were dissolved in a lubricant base oil, as was a conventional prior art additive (calcium phenate) to an alkalinity value of 25 mg K0~/g.
The solutions were then evaluated in the Ring ~elt Merit test Ln a Petter AVl 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 cleanliness. The values for the F.O.M.
are given in Table 2 together with the ash levels and alkalinity values for reference purposes.

~9~
Table 2 ~.O.M. in the Rin~ Belt Merit Test _ ___ _ Sulphated a~h per Product of AVSulphated a~h ~.O.M. unit of AV
Example No. (mg KOH/g) (~) (% x 10-2 Reference 250 31.5 1.0 12.60 225 _ 0.~
4 205 14. 3 o.g6 6.97 201 15.1 0.99 7.51 6 236 15.2 0.89 6.44 7 191 14.0 0.95 7.33 199 1~.8 1.24 6.93 .
Casulphonate 300 38.8 _ 12~93 . _ _.
Examining th~ results shown in Table 2 it can be seen that the compounds of the invention provide approximatsly half as much ash at comparable alkalinity values as prior art additi~es, whilst al80 maintaining similar or better degree~ of piston clea~lines~.
Examples A, B, C, D, E, F, G and H are not examples according to the invention. * A.r. i8 the alkalinity value measured by the procedure in ASTM-D2896. ** The C12-alkyl phenol was prepared by alkylating phenol with propylene tetramer.
Comparison T st 1 (i) Pre~aration of SulPhurised aLkvlphenol To a reaction ves3el was addPd 4448g of a C12-aIXylphenol**, 206.6g CaO a~d 1280g sulphur. The sub3equent procedure was identical to that de~cribed in Example A except that 163g ethylene glycol was added.
(ii) PreParation of Mannich ba~e 699g C12-aIkylphenol**, 113.3 ethylamine and 292.7g lOOS~
lube oil were charged to a reaction ve~sel. Over a period of 1 hour 75.4g fo~maldehyde was added to the reaction mi~ture. Thereafter the procedure described in Example E was followed.
The Nannich base obtained was analysed as follows:-~V* = ~7.b mg EOH/g N = 1.66~o ,~ ~ri9cosity2loop~ = 24.7cS

~L069S~l (iii) Preparation of product The procedure of Example 4 was folloHed employing the following reactants:-201g of the ~annich base prepared as in (ii) above.
148g of the sulphurised alkylphenol prepared a3 in (i) above.
37g Ca(0~)2 120g ethylene glycol 174g lOO~N lube oil ~nalysis of product: C~ = 3.93%
~ ~ 0.12%
S = 3.9%
Viscosity210 ~ 150.6cS
~V* = 120mg ~0~ g ~sh = 13.3~
% asb/u~it ~.V. = 11.08 ~ 10 2 Com~arison Test 2 (i) Pre~aration of MPnnich base To a reaction vessel was added ~99gC12-aIkylphenol~*, 5~.7g ethylamine and 273.3g lOOSN lube oil. Over a period of 1 hour 75.4g formaldehyde was added to the reaction mixture. Thereafter the procedure described in E~ample E was followed.
The MAnn1ch base obtained was analysed as follows:-~V* = b~ mg KOH/g ~ 7%
viscositY2l00F = 15-2 (ii) PreParation_of product - The procedure described in E~ample 4 was followed employing the following reactants:-188g of the Mannich base prepared as in Comparison Test 2(i) above 148g of the sulphurised alkylphenol prepared as in Comparison ~ ~ ;: : ', ,; ;

~o~o~

~est 2 (i) above.
37g Ca~0~) 2 120g ethylene glycol 1~8g lOOSN lube oil ~nalysis of product:- Ca = 4.41~
= 0.12%
S = 3.30~o Viscooity2looF = 129 ~V* = 122 m~E0~/g ~h = 15"2q~o % ash/unit~.V. = 12.4~
In contrast to Examples 4 to 8 the prior art additive incorporating a Mannich base prepared ~rom a simple amine, i.e.
ethylamine, leads to approximately double the amount of ash per u~it of alkalinity value.

.

Claims

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:-

1. A compound suitable for use as a lubricating oil additive consisting of the reaction product obtained by neutralising with an alkaline earth metal compound selected from the oxide and hydroxide 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 an amine compound selected from alkylene and polyalkylene polyamines having the structural formula:- (I) wherein n is an integer having a value in the range from 1 to 10 and the alkylene group contains from 2 to 8 carbon atoms, an alkyl phenol and formaldehyde, said neutralisation being carried out in the presence of a hydroxylic solvent and at an elevated temperature so that molecular bonds are formed between said Mannich base and said sulphurised alkyl phenol in addition to the bridging bonds created by said alkaline earth metal.

2. A compound according to claim 1 wherein said alkylene polyamine is ethylene diamine.

3. A compound according to claim 1 wherein said amino compound is a polyalkylene polyamine selected from diethylene triamine, triethylene tetramine and tetraethylene pentamine.

4. A compound according to claim 1 wherein said Mannich base and said sulphurised alkyl phenol are combined in an equivalent ratio (based on phenol) in the range from 0.2 to 5:1.

5. A compound according to claim 1 wherein the amount of said alkaline earth metal compound added is sufficient to provide a total of up to 1.75 equivalents per equivalent of alkyl phenol present in the final product.

6. A compound according to claim 1 wherein said hydroxylic solvent is selected from ethylene glycol, propylene glycol, butane diol and methanol.

7. A compound according to claim 1 wherein said hydroxylic solvent is ethylene glycol in an amount of from 5 to 35 weight percent of the total reaction mixture.

8. A compound according to claim 1 wherein an inert diluent is present in an amount of from 3 to 65 weight percent of the total reaction mixture.

9. A compound according to claim 1 wherein at least 90 percent of said sulphurised alkylphenol has the structural formula:- (II) wherein R2 is an alkyl group containing from 8 to 36 carbon atoms, said alkyl groups being predominantly in the para-position, y1 is an integer in the range from 1 to 9 and n1 is an integer in the range from 1 to 5, the amount of sulphur present being in the range 4 to 20 weight percent.

10. A compound according to claim 9 wherein in said sulphurised alkyl phenol of structural formula (II) said group R2 is an alkyl group containing from 10 to 30 carbon atoms predominantly in the para-position, said integer y1 has a value in the range from 1 to 5, averaging over the entire composition in the range from about 2 to 4, said integer n1 has a value in the range from 1 to 3 and said sulphur is present in an amount of from 8 to 18 weight percent.

11. A compound according to claim 1 wherein said alkaline earth metal is selected from calcium and barium.

12. A compound according to claim 1 wherein said Mannich base contains from 2 to 10 weight percent nitrogen and has 8 molecular weight as determined by osmometry, in the range 600 to 5,000.

13. A compound according to claim 1 wherein said elevated temperature is in the range 125 to 160°C during removal of the water of reaction.

14. A compound suitable for use as a lubricating oil additive consisting of the reaction product obtained by neutralising with an alkaline earth metal compound selected from the oxide and hydroxide 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 an amino compound selected from alkylene and polyalkylene polyamines having the structural formula:- (I) wherein n is an integer having a value in the range from 1 to 10 and the alkylene group contains from 2 to 8 carbon atoms, an alkyl phenol and formaldehyde, said neutralisation being carried out in the presence of a hydroxylic solvent and at an elevated temperature so that molecular bonds are formed between said Mannich base and said sulphurised alkyl phenol in addition to the bridging bonds created by said alkaline earth metal and wherein after completion of said neutralisation said hydroxylic solvent is removed from said reaction product.

15. A compound according to claim 14 wherein said hydroxylic solvent is ethylene glycol which is removed from said reaction product by heating at a temperature in the range 160 to 200°C whilst maintaining the pressure in the range 0.01 to 0.8 atmospheres.

16. A compound according to claim 14 wherein after said hydroxylic solvent is removed said reaction product is diluted with an inert diluent and filtered.

17. A concentrate composition suitable for formulating finished lubricating oils consisting of a minor proportion of hydrocarbonaceous lubricating oil and a major proportion of an additive package consisting of the compound as claimed in claim 14 alone or in combination with conventional additives.

18. A finished lubricant composition consisting of a major proportion of a lubricant base oil and a minor proportion of the concentrate composition as claimed in claim 17.