GB1568959A

GB1568959A – Process for the production of a product suitable for use as a lubricating oil additive
– Google Patents

GB1568959A – Process for the production of a product suitable for use as a lubricating oil additive
– Google Patents
Process for the production of a product suitable for use as a lubricating oil additive

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Publication number
GB1568959A

GB1568959A
GB4198275A
GB4198275A
GB1568959A
GB 1568959 A
GB1568959 A
GB 1568959A
GB 4198275 A
GB4198275 A
GB 4198275A
GB 4198275 A
GB4198275 A
GB 4198275A
GB 1568959 A
GB1568959 A
GB 1568959A
Authority
GB
United Kingdom
Prior art keywords
process according
product
earth metal
alkaline earth
mannich base
Prior art date
1975-10-14
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)

Expired

Application number
GB4198275A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)

Orobis Ltd

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Orobis Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
1975-10-14
Filing date
1975-10-14
Publication date
1980-06-11

1975-10-14
Application filed by Orobis Ltd
filed
Critical
Orobis Ltd

1975-10-14
Priority to GB4198275A
priority
Critical
patent/GB1568959A/en

1976-10-14
Priority to DE19762646439
priority
patent/DE2646439A1/en

1976-10-14
Priority to JP12339276A
priority
patent/JPS5263204A/en

1976-10-14
Priority to NL7611346A
priority
patent/NL7611346A/en

1976-10-14
Priority to BE171516A
priority
patent/BE847284A/en

1976-10-14
Priority to FR7630869A
priority
patent/FR2328037A1/en

1980-06-11
Publication of GB1568959A
publication
Critical
patent/GB1568959A/en

Status
Expired
legal-status
Critical
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Classifications

C—CHEMISTRY; METALLURGY

C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT

C10M—LUBRICATING COMPOSITIONS; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATING INGREDIENTS IN A LUBRICATING COMPOSITION

C10M159/00—Lubricating compositions characterised by the additive being of unknown or incompletely defined constitution

C10M159/12—Reaction products

C10M159/20—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products

C10M159/22—Reaction mixtures having an excess of neutralising base, e.g. so-called overbasic or highly basic products containing phenol radicals

Description

(54) PROCESS FOR THE PRODUCTION OF A PRODUCT SUITABLE
FOR USE AS A LUBRICATING OIL ADDITIVE
(71) We, OROBIS LIMITED, of 36/44 High Street, Redhill, Surrey, RHi 1RW, 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:
This invention relates to a process for the production of a product suitable for use as a lubricating oil additive and to the product so-produced.
Lubricating oils used under the severe conditions of diesel engines are highly compounded so as to provide neutralization of acids derived from the sulphur in the fuel and oxidation of hydrocarbons, both of the fuel and oil: dispersancv so as to maintain sludge-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 railwav diesel engines have the additional factor 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 economies in the manufacturing and using 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 fulfill the function(s) for which it has been designed, but that it be stable under the conditions of use or degrade 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 sulphurized 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 polyamines with sulphur-bridged 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 alkylphenol containing at least 4 weight per cent sulphur and a Mannich base containing at least 2 weight per cent nitrogen and having a molecular weight of 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.
It has now been found that new phenates having a lower ash content for the same degree bf alkalinity reserve result when the Cl to C3 alkyl amine used in the preparation of the
Mannich base is replaced by an alkylene diamine or polyalkylene polyamine.
Accordingly the present invention provides a process for the production of a product suitable for use as a lubricting 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 per cent 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 per cent sulphur and,
(C) a Mannich base containing at least 2 weight per cent 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 + alkylene – NH + nH (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 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.
The products of the present invention are complex in nature. Because of the varietv 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 meaningless.
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, 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 n 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 y’ greater than 9.
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 pam-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 ortho position. and ortho-substituted phenols act as chain terminators in the copolymerisation of sulphur and alkylphenol. Sulphurised alkylphenols of formula (II) preferably form greater than 90C/c of the mixture (B).
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 alkylphenol.
See for example US Patent No 2.989.466. Sulphur monochloride may also be used to prepare sulphurised alkylphenols, frequently employing a Friedel-Crafts catalyst to aid the reaction. Various methods of preparing sulphurised aikylphenols may be found in US
Patents Nos. 2,362,289, 2,451,354. 2,744,083 and 3.367.867.
The Mannich bases (C) which are employed may be prepared bv combining at elevated temperatures, an alkylphenol. formaldehyde and the alkylene diamine or polyalkylene polyamine, preferably ethylene diamine. 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 in the alkyl group. The formaldehyde may be added in the form of an aqueous solution (formalin) or in a polymeric form eg paraformaldehyde. A method for preparing Mannich bases may be found in UK Patent No 1,345,030. US Patent No 3.454.497 describes an additional method for preparing Mannich bases employing primarv amines.
The alkylene group of the diamine or polyamine of formula (I) is preferably ethylene, propylene or butvlene. The alkylene diamine is preferably ethylene diamine. Polyalkylene polyamines which may be used include diethylene triamine, triethvlene 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 preferably have at least 2 weight per cent nitrogen and ,normally not more than 10 weight per cent nitrogen. The average molecular weight, as Fletermined by osmometry, is at least 600, more usually at least 700, and normally not
exceeding about 5,000.
The Mannich base may be in the mono- or bis-form, the particular form being governed
by the ratio of alkylphenol to amine in the initial preparative mixture.
The alkaline earth metal oxide or hydroxide is preferably an oxide or hydroxide of
calcium or barium, even more preferably of calcium.
Ethylene glycol, propylene glycol, butane diols and methanol are examples of suitable 4ydroxylic 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 per
cent, of the total reaction mixture.
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 enchancing 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 mixture, if at all, in amounts from 3 to 65 weight per cent. more
usually 5 to 50 weight per cent of the total reaction mixture.
Conveniently, a small amount of an anti-foaming agent or foaming suppressant may be
employed. The foam suppressant may be present in the reaction mixture in amounts of 1 x 10 to 1 > < x 10-5 10- weight per cent. Foam suppressants are conventional and need not be exemplified here. The reaction may be conveniently carried out by combining either the sulphurised alkylphenol (A) or the mixture (B), the Mannich base (C). the alkaline earth metal oxide or hydroxide, and the hydroxylic solvent, eg 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 alkylphenol and an alkaline earth metal salt of a sulphurised alkylphenol, ie (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 alkylphenol 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 temperature in the range from 90 to 125"C. the hvdroxylic solvent is then added and the resulting mixture is thereafter heated at a temperature 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 minutes to 3 hours. 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 solvent after formation of the product. In the case where the hydroxylic solvent is ethylene glycol it mav conveniently be 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. 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 to accomplish the complete reaction, that is from the initial removal of water to substantially complete removal of ethylene glycol may vary from 1 hour to 6 hours. 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 abilitv 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 1500C 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 hydrocarbonaceous lubricating oils may be employed. The amount of hydrocarbonaceous lubricating oil added is preferably 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 off any undesirable insoluble compounds. 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 per cent alkaline earth metal, at least 0.1 to 5, more usually from 0.5 to 4, weight per cent nitrogen, and from 0.8 to 10, more usually from 1 to 8 weight per cent 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 per cent for Ca), the viscosity at 210 F. 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 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 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 dodecyl-phenol. which was prepared by alkylating phenol with propylene tetramer. Preparation of sulphurised alkyl phenol Example A To a reaction vessel was added 2240g of a dodecyl-phenol. 103g of CaO and 642g of sulphur. The mixture was heated to 125"C and 81.5g of ethylene glycol slowly added. The temperature was then raised to 1500C at a pressure of 550 mm Hg. Water was removed over a period of 1 hour and then the temperature further raised to 195"C under full vacuum (50 mm Hg pressure) for 2 hours. The product was analysed and had the following composition: S = 14.4Sc Ca = 2.8'tic Alkalinity Value (AV) = 72.2 mg KOH/g Example B To a reaction vessel was added 2224g of a dodecyl phenol. 144g of Ca(OH)2 and 642g of S. The subsequent procedure was identical to that described in Example A. The analysis of the product was as follows: Ca = 2.86CHc S = 15.06Xc AV = 81.2 mg KOH/g Example C To a reaction vessel was added 4448g of a dodecyl-phenol. ; 296g Ca(OH). and 1280g sulphur. The subsequent procedure was identical to that described in Example A except that 165g ethylene glycol was added. Furthermore after heating at 195"C and 50 mm Hg pressure the product was diluted with 2108g 100 Solvent Neutral lube oil and filtered. The analysis of the product was as follows: AV = 57.7 mg KOH/g Ca =199cue S = 1 1 .06CHe Viscosity 210"F = 99.2 cS Example D To a reaction vessel was added 1960g of a dodecyl-phenol 98g CaO and 560g sulphur. The subsequent procedure was identical to that described in Example A except that 77g ethylene glycol was slowly added. The analysis of the product was as follows: S = 16.6% Ca = 2.59% AV = 66.3 mg KOH/g Preparation of Mannich Base Example E To a reaction vessel was charged 2240g of a dodecyl-phenol. 24()g ethylene diamine and 500my. toluene. To the mixture was added 678g of aqueous formaldehyde solution over a period of 1 hour. The temperature was raised to X() C and was held at this value for 1 hour. By raising the temperature to 1500C all the water was distilled off. The product mixture was cooled and washed with water to remove unreacted ethylene diamine. The mixture was then stripped to remove water and filtered - llO"C for 2 hours. The product was analysed for nitrogen content and its alkalinity value (A.V.) and viscosity at 2100F measured. The following results were obtained: A.V. = 158.4 mg KOH/g Nitrogen content = 3.87% Viscosity 210 F = 726cS Example F 4656g of dodecyl-phenol, 824g 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 was heated to a final base temperature of 140"C during which time the water produced during the reaction was removed by azeotropic distillation. The product was then washed with 1 litre of water which was removed by azeotropic distillation. Finally the product was filtered. A.V. = 225 mg KOH/g N content = 5.81% Viscosity 210 F = 390 cS Example G 2160g dodecyl-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. Thereafter the procedure described in Example F was followed. The product obtained was analysed as follows: A.V. = 279 mg KOH/g N = 7.38% Viscosity 210 F = 406 Example H 4620g of a dodecyl-phenol. 858g diethylene triamine and 990g 100 Solvent Neutral lube oil were charged to a reaction vessel. 375g paraformaldehyde was then added slowly to the mixture. The mixture was heated to 120 to 1250C and held at that temperature for 2 hours during which the water produced in the reaction was removed bv distillation. To ensure removal of all the water the product was vacuum stripped at 20 mm Hg pressure and 1300C base temperature for 30 mins. On cooling a further 980g of 100 Solvent Neutral lube oil was added. The product was analysed as follows: A.V. = 179.4 mg KOH/g N = 4.26% Viscosity 210 F = 23.8 cS Preparation of final product Example 1 261g of the Mannich Base product from Example E, 74Xg of the sulphurised alkylphenol product from Example D and 83.5g of lube oil (100 Solvent Neutral) were charged to a reaction vessel and the temperature raised to 900C when 18.5g of Ca(OH)2 and 60.3g of ethylene glycol were added. The temperature was raised to 150"C and the pressure reduced to 50 mm Hg over a period of 2 hours. Finally the temperature was raised to 185"C 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 (AV) measured. The following analysis was obtained: Ca = 2.18% S = 2.10ass N = 1.61% A.V. = 195.4 mg KOH/g Example 2 261g of the Mannich Base product from Example E. 74.8 of the sulphurised alkylphenol product from Example D and 83.5g of lube oil (100 Solvent Neutral) were charged to a reaction vessel and the procedure described in Example 1 followed except that 37g Ca(OH)2 and 120g ethylene glycol were added. The analysis of the product was as follows: Ca = 4.29% S = 1.14% N = 2.21% A.V. = 195.4 mg KOH/g Example 3 284g of the Mannich Base product from Example G, 74.6g of the sulphurised alkylphenol product from Example A and 125.5g of lube oil (100 Solvent Neutral) were charged to a reaction vessel and the procedure described in Example 1 repeated except that 37g of Ca(OH) and 120g ethylene glycol were added. The analysis of the product was as follows: Ca = 3.84% S = 1.73% N = 3.98Yc A.V. = 259 mg KOH/e Viscosity 21 F = 2474cS Example 4 1000g of the Mannich Base product from Example F. 745g of the sulphurised alkylphenol product from Example A and 611g of 100 Solvent Neutral lube oil were charged to a reaction vessel and heated to 90"C when 185g Ca(OH) and 601g ethylene glycol were added. The temperature was raised to 1250C and held at this value for 15 mins. The pressure was then reduced to 5()0 mm Hg whilst maintaining the temperature at 125"C and the reaction mixture held under these conditions for a further 15 mins. At the same pressure the temperature was raised to 1500C and held at this value for l hour. The product was then vacuum stripped at 185"C and 50 mm Hg pressure for 15 mins. Finally the product was cooled, 88g 100 Solvent Neutral lube oil added and filtered. The analysis of the product is given in Table 1. Example 5 2660g of the Mannich Base product from Example F. 1865g of the sulphurised alkylphenol from Example A and 1583g 100 Solvent Neutral lube oil were charged to a reaction vessel and the procedure described in Example 4 followed except that 1505g ethylene glycol, 463g Ca(OH)2 and a further 226g 1()0 Solvent Neutral lube oil were added. The analysis of the product is given in Table 1. Example 6 1171g of the Mannich Base product from Example F. 552g of the sulphurised alkylphenol product from Example A and 6()3g 100 Solvent Neutral lube oil were charged to a reaction vessel and the procedure described in Example 4 followed except that 601g ethylene glycol. 185g Ca(OH)2 and a further 86g 1UO Solvent Neutral 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 sulphurised alkylphenol product from Example B and 623g 100 Solvent Neutral lube oil were charged to a reaction vessel and the procedure described in Example 4 followed except that 6()tug ethylene glycol, 185g calcium hydroxide and a further 267g 1(10 Solvent Neutral lube oil were added. The analysis of the product is given in Table l. Example 8 1440g of the Mannich Base product from Example H. 995g of the sulphurised alkylphenol product of Example C and 611g of 100 Solvent Neutral lube oil were charged to a reaction vessel and heated to 1200C when 185g Ca(OH)2 and 600g ethylene glycol were added. The procedure described in Example 4 was then followed except that a further 265g 100 Solvent Neutral lube oil was added. The analysis of the product is given in Table 1. TABLE 1 Analysis of products Product of Analysis Example AV V21 F Ca(%) N(%) S(%) 4 205 1333 4.29 2.31 2.83 5 201 2720 4.15 2.47 2.95 6 236 2164 4.35 2.64 2.47 7 191 596 4.25 2.14 2.78 8 199 331 4.09 2.38 2.75 Example 9 Engine 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 KOH1/3G. The solutions were then evaluated in the Ring Belt Merit test in a Petter (Petter is a Registered Trade Mark) AV1 engine running under standard conditions but modified to run on residual fuel containing approximately 2.8cue 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 +(). 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. TABLE 2 F.O.M. in the ring belt merit test Sulphated ash per Product of AV Sulphated ash F.O.M. unit of AV Example No. (mg KOH/g) (%) (CiC x 10-2) Reference 250 31.5 1.0 12.60 F 225 - 0.3 4 205 14.3 0.96 6.97 5 201 15.1 0.99 7.51 6 236 15.2 O.X9 6.44 7 191 14.0 0.95 7.33 8 199 13.8 1.24 6.93 Casulphonate 300 38.8 - 12.93 Examining the results shown in Table 2 it can be seen that the compounds of the invention provide approximately half as much ash at comparable alkalinity values as prior art additives, whilst also maintaining similar or better degrees of piston cleanliness. Examples A, B, C, D, E, F, G and H are not examples according to the invention. Comparison Test 1 (i) Preparation of Sulphurised alkvlphenol To a reaction vessel was added 4448g of a dodecyl-phenol. 206.6g CaO and 1280g 'sulphur. The subsequent procedure was identical to that described in Example A except that 163g ethylene glycol was added. (ii) Preparation of Mannich base 699g dodecyl-phenol;", tz 113.3g ethylamine and 292.7g 101) Solvent Neutral lube oil were charged to a reaction vessel. Over a period of I hour 75.4g formaldehyde was added to the reaction mixture. Thereafter the procedure described in Example E was followed. The Mannich base obtained was analysed as follows: AV = 67.6 mg KOHlg N = 1.66% Viscosity 210 F = 24.7cS (iii) Preparation of product The procedure of Example 4 was followed employing the following reactants: 201g of the Mannich base prepared as in (ii) above. 148g of the sulphurised alkylphenol prepared as in (i) above. 37g Ca(OH)2 120g ethylene glycol 174g 100 Solvent Neutral lube oil Analysis of product: Ca = 3.S3C,cDownload PDF in English