The invention relates to improvements in the manufacture of polymers of olefinicalry unsaturated hydrocarbons, and has particular relevance to the manufacture of polymers which may be used for making lubricating or fuel oil additives, although it is also applicable to the manufacture of polymers for other uses.

As is well known, lubricating oils, for example those used as crankcase lubricants in internal combustion engines in automobiles and trucks, must normally contain a number of different additives to improve their efficiency and useful life. Thus, for example, for the past 30 to 50 years, crankcase lubricating oils have normally contained ashless dispersants, for example, the reaction products of amines and/or alcohols, including amino-alcohols, with hydrocarbyl-substituted mono-or dicarboxylic acids, long chain aliphatic hydrocarbons having one or more polyamine molecules attached directly thereto, and Mannich condensation products containing a long chain hydrocarbyl group, for example, as a substituent of a phenol; metal-containing detergents, for example, calcium or magnesium salts, which are normally overbased, of sulphonic acids, alkyl phenols, sulphurised alkyl phenols, alkyl salicylates, naphthenates, and other oil-soluble mono- and dicarboxylic acids; and antioxidants, for example, amines, hindered phenols, and sulphurised phenols, and zinc dihydrocarbyl dithiophosphates (ZDDPs). The ZDDPs are primarily antiwear agents, but also provide antioxidant activity. Lubricants may also contain other additives, for example, viscosity modifiers, rust inhibitors, corrosion inhibitors, and pour point depressants. Of course, not all lubricants contain additives from all the classes mentioned, and any given additive may perform more than one function in the oil.

Fuels, depending on their intended function, may contain, for example, one or more additives such as flow improvers, wax crystal modifiers, pour point depressants, ashless dispersants and metal-containing detergents, for example, ashless dispersants and detergents as described above in relation to lubricating oils.

In view of the very considerable commercial importance of lubricating and fuel oil additives, many different proposals have been made over many years for improving processes for their production. Despite the very considerable work that

has been carried out in this field, however, the applicants -have found that it is possible, in a relatively simple manner, to make very significant improvements in the production of certain polymers which may be used, inlfiralia. in the manufacture of lubricating and fuel oil additives, although the polymers may also have other uses.

The invention provides a process for the manufacture of a homo- or interpolymer, in which at least one olefinically unsaturated hydrocarbon and, optionally one or more other copoiymerizable monomers, is polymerized in a polymerization mixture in the presence of a polymerization catalyst, such that there are at least two different phases in the mixture, polymerization being carried out, at least partially, in a region defined by a surface and at least one member adjacent to the surface, there being relative movement between the surface and the membβr(s) such that the polymerization mixture is caused to move relative to the surface. Advantageously, the region is defined by adjacent surfaces between which there is relative movement such that the polymerization mixture is caused to move relative to one or both of the surfaces.

The invention also provides a process for the manufacture of a homo- or interpolymer, in which at least one olefinically unsaturated hydrocarbon and, optionally one or more other copoiymerizable monomers, is polymerized in a polymerization mixture in the presence of a polymerization catalyst, such that there are at least two different phases in the mixture, polymerization being earned out, at least partially, in a thin film on a surface over which the moπomer(s) and catalyst move, the average velocity (taken across the thickness of the film) of the polymerization mixture in a direction parallel to the surface being at least 1 m/sec. The thin film is advantageously formed between the surface and at least one member adjacent to the surface, preferably between adjacent surfaces, there being relative movement between the surface and the member(s), or between the surfaces, causing the said movement of the polymerization mixture.

The invention also provides an olefinically unsaturated hydrocarbon polymer or interpolymer prepared by a process in accordance with the invention.

Olefinically unsaturated hydrocarbons to be polymerized by a process in accordance with the invention may be aliphatic or aromatic. The invention has particular relevance to the preparation of polymers of mono-unsaturated aliphatic

hydrocarbons, or alkenes. Aliphatic hydrocarbons may contain straight or branched chains, or alicylic groups.

The olefinically unsaturated hydrocarbons advantageously contain at most 20 carbon atoms, and are preferably mono-unsaturated aliphatic hydrocarbons having 2 to 20 carbon atoms.

Inteφolymers of two or more olefinically unsaturated hydrocarbons may be prepared in accordance with the invention. As examples of such interpolymers there may be mentioned inteφolymers of ethylene and a C3 to Cβ alpha-olefin, for example, propylene, and interpolymers of two or more olefinically unsaturated hydrocarbons, particularly mono-unsaturated aliphatic hydrocarbons, each having an even number of carbon atoms, for example, interpolymers of Cβ to C ₁ 8 α-olefins having an even number of carbon atoms, for example C10/C-12/C-1 terpolymers.

Examples of monomers which may be copolymerised with at least one olefinically unsaturated hydrocarbon (to give an intβφolymer) using the process of the invention are aryl-substituted alkenes, particularly aryl-substituted C2 to C20 alkenes; bicycloalkenes; and dienes, for example, butadiene, isoprene and norbornene.

Any suitable polymerization catalyst may be used in accordance with the invention. Examples of catalysts which may be used are AICI3, HF, BF3, AIBr3, and organo-aluminium chlorides. The catalysts may if desired be used together with co-catalysts or promoters, for example, HCI, alkyl chlorides, alkanols (for example, methanol, ethanol, propanol, isopropanol, butanol and tert. butanol), phenols, and Ci to C4 alkyl esters of such hydroxy compounds. Preformed complexes of these catalysts and co-catalysts may be used, for example AICI3- ethanol complexes and HF-ethanol complexes. An advantageous catalyst system comprises HCI with AICI3 or an organo-aluminium catalyst.

The organo-aluminium chloride catalysts which may be used in the process of this invention include compounds of the formula

wherein R represents a Ci to C20 hydrocarbyl group and x is 1 or 2. R may represent a branched or straight chained alkyl, cycloalkyl, aryl, aJkaryl, aralkyl, alkenyl, or alkynyi group, or a hydrocarbyl (e.g. Ci to C10) * substituted derivative thereof. When R represents an alkyl group, the alkyl group may contain from 1 to 20, preferably from 1 to 10, and most preferably from 1 to 4, carbon atoms. Illustrative of such alkyl groups are methyl, ethyl, isopropyl, propyl, n-butyl, isobutyl, tertbutyl, peπtyl, hexyl, heptyl, octyl, nonyl, decyl, dodecyl, tridecyl, tetradecyl and octadecyl groups. When R represents an alkenyl group, the alkenyl group may contain from 2 to 20, preferably from 2 to 10, and most preferably from 2 to 4, carbon atoms. Illustrative of such alkenyl groups are ethenyl, isopropenyl, propenyl, n-butenyl, isobutenyl, tertbutenyl, pentenyl, hexenyl, heptenyl, octenyl, nonenyl, decenyl, dodecenyl, tridecenyl, tetradecenyl, and octadecenyl groups. When R represents an alkynyi group, the alkynyi group may contain from 2 to 20, preferably from 2 to 10, and most preferably from 2 to 4, carbon atoms. Illustrative of such alkynyi groups are ethynyl, isopropynyl, propynyl, n-butynyl, isobutynyl, tert.butynyl, pentynyl, hexynyl, heptynyl, octynyl, nonynyl, decynyl, dodecynyl, tridecynyl, tetradecynyl, and octadecynyl groups. When R represents an aryl group, the aryl group may contain from 6 to 10 carbon atoms. Illustrative of such aryl groups are phenyl, naphthyl and the like. When R represents an alkaryl group, the alkaryl group may contain from 7 to 20, preferably from 7 to 15, and most preferably from 7 to 10, carbon atoms. Illustrative of such alkaryl groups are tolyl, xylyl, di(ethyl)phenyl, and di(hexyl)phenyl groups. When R represents an aralkyl group, the aralkyl group can contain from 7 to 20, preferably from 7 to 15, and most preferably from 7 to 10, carbon atoms. Illustrative of such aralkyl groups are benzyl, ethylbenzyl, phenylhexyl, and naphthylhexyl groups. When R represents a cycloalkyl group, the cycloalkyl group may contain from 3 to 20, preferably from 3 to 10, and most preferably from 3 to 4, carbon atoms. Illustrative of such cycloalkyl groups are cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cyclododecyl, cyclotridecyl, cyclotetradecyl, and cyclooctadecyl groups. Illustrative of hydrocarbyl-substituted derivatives of the foregoing groups are 2- ethylcyclohexyl, cyclopropylphenyl, and pheny Icy lo hexyl groups.

Examples of organo-aluminium chlorides which may be used as catalysts are (CH ₃ )AICl ₂ , (CH ₃ )2AICI, C2H5AICI2, (C ₂ H ₅ )2AICI, (CH ₃ ) ₂ CHAICl2. [(CH ₃ )2CH] ₂ AICI, (C ₃ H ₇ )AICI ₂ , (C ₃ H ₇ )2AICI, CH ₃ CH(CH ₃ )AICl2, [CH ₃ CH(CH ₃ )]2AICI, (CH ₃ )3CAICI ₂ , [(CH ₃ )3C] ₂ AICI, C ₆ H ₁₃ AICI ₂ , C5HHAICI2,

C10H21AICI2, and mixtures thereof. Especially preferred are C2H5AICI2, (C2H5)2AICi and mixtures thereof. Preferred are organo-aluminium chloride catalysts which are liquids under the reaction conditions.

Especially preferred catalysts are AICI3, BF3, and organo-aluminium chlorides wherein R in the above formula represents a Ci to C4 alkyl group.

The polymerization mixture used in the process of the invention comprises at least two components which are to some extent mutually insoluble, that is, components in different phases. In most cases, the catalyst will be in a different phase from the monomers, or at least one of the monomers, but the components which are to some extent mutually insoluble could in some cases be, for example, two monomers. There may of course be situations where more than two mutually insoluble components are present.

The polymerization mixture containing at least two components which are to some extent mutually insoluble may also, if desired, contain an inert solvent or diluent, for example, a saturated hydrocarbon solvent, although where one of the components is present in liquid form, the use of a solvent or diluent is preferably avoided. Polymerization may be carried out at a pressure greater than atmospheric pressure if, for example, this is necessary in order to ensure that at least one component of the polymerization mixture is present in liquid form, In a preferred embodiment of the invention, the monomer, or at least one of the monomers, and the catalyst, independently, are each present in the polymerization mixture as a liquid or solid.

The process of the invention may be carried out batchwise, semicontinuously or, preferably, continuously. It may be desirable to cool the polymerization mixture during polymerization to remove heat produced in an exothermic reaction.

The composition of the polymerization mixture will, in a batchwise process, vary with time and, in a continuous process, vary with the point at which the composition is measured. Normally, however, the polymerization mixture will comprise, in addition to the catalyst, some unreacted monomer(s), some monomer(s) in the process of polymerization, and some polymeric material produced by the polymerization reaction.

As indicated above, the process of the present invention may be used for the manufacture of polymers which may be used for making lubricating or fuel oil additives, although polymers made by the process of the invention may also have other uses. Examples of additives which may be made from the polymers are dispersants and metal-containing detergents. Such additives are discussed in greater detail below.

Polymers which have proved particularly useful in the manufacture of lubricating or fuel oil additives are the polybutenes. Thus, for example, polyisobutylenes are of particular importance in the production of dispersants for lubricating and fuel oils, while poly-n-butenes are particularly useful as feedstocks for the production of lubricating oil detergents. Examples of specifications describing the preparation of polybutenes are European Specifications Nos. 101 205 A, 367 385A and 370 805A, the disclosures of all of which are incorporated herein by reference.

The use of a process in accordance with the invention may, for example, give improved yields, and/or a polymer of narrower molecular weight range. Polymers of narrow molecular weight range may have particularly desirable properties which may be carried over into substances, for example lubricating oil and fuel oil additives, made from them.

Accordingly, the invention also provides the use of apparatus comprising a reaction region defined by a surface and at least one member adjacent to the surface, and means for causing relative movement between the surface and the member(s), to give improved yields, and/or a polymer of narrower molecular weight range, in a process for the manufacture of a homo- or interpolymer comprising units derived from at least one olefinically unsaturated hydrocarbon. The invention further provides the use of apparatus comprising means for causing reactants to move in a thin film over a surface, to give improved yields, and/or a polymer of narrower molecular weight range, in a process for the manufacture of an homo- or interpolymer comprising units derived from an olefinically unsaturated hydrocarbon.

In accordance with one aspect of the invention, a polymerization mixture comprising components in different phases is treated in a region defined by a surface and at least one member adjacent to the surface, there being relative

movement between the surface and the members) such that the mixture is caused to move relative to the surface. Advantageously, the region is defined by adjacent surfaces between which there is relative movement such that the mixture is caused to move relative to one or both of the surfaces.

Because the surface and the member(s) (or, in the preferred case, the two surfaces) defining the polymerization region are adjacent to each other, polymerization takes place in a thin film and the polymerization mixture is caused to move relative to the surface or, if there are two surfaces, to at least one of the surfaces. The very high mechanical forces exerted on the polymerization mixture as a result of the arrangement and action of the surface/member(s) and the surfaces result in significant improvements as described elsewhere in this specification.

In a further aspect of the invention, the polymerization mixture is caused to move in a thin film on a surface, the average velocity (taken across the thickness of the film) of the polymerization mixture in a direction parallel to the surface being at least 1 m/sec, the thin film advantageously being formed between the surface and at least one member adjacent to the surface, preferably between adjacent surfaces, there being relative movement between the surface and the member(s), or between the surfaces, causing the said movement of the polymerization mixture.

A thin film in accordance with the invention advantageously has a thickness of at most 25 mm, preferably at most 20 mm, and especially at most 15 mm. In particular applications, film thicknesses in the range of from 0.1 to 10 mm, especially 0.2 to 10 mm, have been found to be especially advantageous.

Although the invention extends to arrangements where this is not the case, the film thickness is advantageously determined by the width of the gap between the surface and at least one member adjacent to the surface (and preferably, between adjacent surfaces), and the said gap advantageously has a width of at most 25 mm, preferably at most 20 mm, and especially at most 15 mm. (In accordance with the invention, therefore, the surface and the member, or two surfaces, are said to be "adjacent" if they define a polymerization reaction which advantageously has a thickness of at most 25 mm.) In particular forms of apparatus suitable for use in accordance with the invention, gaps with a width in

the range of from 0.1 to 10 mm, especially 0.2 to 10 mm, have been found to be particularly advantageous. The width of the gap need not be constant throughout the polymerization region.

Where there is a thin film of material between a surface and at least one member adjacent to the surface (preferably between adjacent surfaces), relative movement of the surface and the member(s) or between the surfaces causes movement of the polymerization mixture relative to the or a surface. In the preferred case, discussed in more detail below, where the surface, or one of the surfaces, is stationary and the member(s) or the other surface moves, the mixture will tend to move in a direction parallel to the stationary surface with an average velocity less than, but for a thin film approaching, that of the adjacent moving member/surface. Thus, for example, where polymerization is effected in a thin film formed between an inner rotor and an outer stator, the polymerization mixture will tend to move over the surface of the stator with an average velocity less than, but approaching, the peripheral velocity of the rotor. In accordance with the invention, the mixture advantageously moves with an average velocity (taken across the thickness of the film) of at least 1 m/sec, advantageously at least 5 m/sec, and preferably at least 10 m/sec, and these are preferred peripheral velocities for the rotor in arrangements where the polymerization is effected in a region defined by an inner body and an adjacent outer housing, one of which, preferably the inner body, forms a rotor and the other of which forms a stator. In one particularly preferred arrangement having a central rotor and an outer stator, a peripheral speed of the rotor in the range of from 20 to 30 m sec was found to be especially advantageous.

In an embodiment not at present preferred, both the surface and the member(s), or both the surfaces, move. If the surface and member(s), or the two surfaces, move in opposite directions (for example, if an inner body and an adjacent outing housing are rotated in opposite directions),the minimum average velocity of 1 m/sec mentioned above is the velocity relative to the surface or one of the surfaces.

It will be appreciated that the movement of the polymerization mixture will normally have components in more than one direction. Thus, for example, in an arrangement where polymerization is effected in a region defined by an inner body and an adjacent outer housing, one of which rotates, the movement of the

mixture will normally have components in the axial and radial directions as well as in the tangential direction. In such an arrangement, the minimum average velocity of 1 m/sec referred to herein is the component of velocity in the tangential direction. As indicated above, where the inner body and outer housing are adjacent to each other so that there is a thin film of material between them, the polymerization mixture has an average velocity (taken across the thickness of the film) having a component in the tangential direction approaching the peripheral speed of the rotor.

When the polymerization region is defined by a surface and at least one member adjacent to the surface (and, preferably, by two adjacent surfaces), the surface and/or the member(s) (or one or both of the surfaces) may be caused to move, although it is normally preferred that the or a surface remains stationary. Any type of movement may be employed. Thus, for example, the movement may be an oscillatory movement. Advantageously, however, the member(s) or, where there are two surfaces, one of the surfaces, rotates, the, or the other, surface remaining stationary.

Where the polymerization region is defined by a surface and at least one member adjacent to the surface, the or each member may comprise, for example, a blade extending radially outwardly from a shaft which, in use, is rotated at high speed. Such rotation will cause the polymerization mixture to form a thin film on the surface and to move over the surface. There may also be at least one zone where centrifugal forces cause the polymerization mixture, or components thereof, to travel in a generally radial direction at a considerable velocity before meeting the surface. In some cases, centrifugal forces may be sufficient to maintain on the surface a thin film whose thickness is less than the width of the gap between the surface and the outer extremities of the blades.

In the preferred case, where polymerization takes place in a region defined by two surfaces, the polymerization region may, if desired, be defined by opposing surfaces of two plates, for example, discs, although this arrangement is not at present preferred. Preferably one of the plates is rotated at high speed, for example, from 500 to 10,000 rpm, depending on the diameter, while the other plate is stationary. The opposing surfaces of the plates are relatively close to each other (that is, adjacent to each other) so that only a thin film of material is present between them at any one time, the gap between the plates preferably

being, for example, of the order of 0.2 to 25 mm. The plates may be, for example, discs having a diameter of up to 50 cm, although larger diameters are not excluded. Where one disc is rotated and the other is stationary, the peripheral velocity of the rotating disc is advantageously at least 1 m sec, advantageous and preferred velocities being as indicated above in connection with a rotor/stator arrangement

In a particular preferred embodiment of the invention, the polymerization region is a generally annular region defined by a surface of an inner body and a surface of an outer housing, and the material in the region is caused to move by rotation of the inner body and/or the outer housing, advantageously by rotation of the inner body while the housing remains stationary.

References to a "generally annular" region include not only the case where the inner body is in the form of a right circular cylinder and the inner surface of the housing is also smooth, but also the case where one or both of the opposed surfaces defining the region is not smooth. Thus, for example, one or both of the surfaces may have one or more protrusions thereon or one or more depressions therein (including the cases where there is a single helical protuberance and/or a single helical groove) or may be, for example, toothed or corrugated. For example, the outer housing may have a plurality of inwardly-extending protrusions thereon, the protrusions, which are preferably all of the same size and shape as one another, preferably being spaced apart at regular intervals on the inner surface of the outer housing, and the inner body (the rotor in this case) may have a plurality of outwardly extending regularly spaced projections of the same size and shape as one another. Alternatively, or in addition, the inner body or the housing may have one or more apertures or discontinuities (for example, slots) therein.

Although in the preferred arrangements described above, the outer diameter of the inner body (or, where the inner body is not in the form of a right circular cylinder, the diameter of the volume swept out by the inner body if it were to rotate) and the inner diameter of the housing (or the diameter of the volume that would be enclosed in the interior of the housing if it were to rotate) are advantageously constant along the length of the rotor, one or both of the diameters may vary along the length of the gap. Thus, for example, starting from one end of the inner body and housing, the inner diameter of the housing may remain constant or decrease, while the external diameter of the inner body increases, or both said diameters

SUBSTITUTE SHEET

may increase but at different rates, or the external diameter of the inner body may remain constant while the internal diameter of the housing decreases.

In the arrangements discussed above, the inner body may be located coaxialiy or eccentrically with respect to the housing, but preferably the housing and inner body are radially symmetrical and coaxial.

As indicated earlier, the inner body and/or the outer housing may have one or more apertures or discontinuities therein. Such apertures or discontinuities enable material to pass through the body in question in a generally radial direction, so that, for example, the polymerization mixture, or components thereof, fed to the centre of a hollow rotor can travel radially outwards to react in the gap between the rotor and stator. Further, the stator may also, or alternatively, have apertures and or discontinuities therein. Where the rotor and/or stator has apertures or discontinuities, it may be possible to use more than one rotor and/or more than one stator. Thus, for example, the mixture or components may pass outwardly, in a generally radial direction, through a first stator, a rotor, and a second stator.

Apertures or discontinuities may of course be present in any body providing a surface referred to in this specification. Where such an annular body has a plurality of discontinuities in the form of slots therein, the body can, in the extreme case, be regarded as a plurality of members as discussed elsewhere in this specification.

Where materials pass through a body providing a surface they will in general be subjected to additional forces, for example, shearing forces, which may enhance the results obtainable in accordance with the invention. Shearing forces may be of importance in all aspects of the invention.

An especially advantageous reactor for use in accordance with the invention comprises an outer casing having within it one or more stators, which may be interconnected with each other, and one or more rotors, which may also be interconnected with each other, such that there is at least one polymerization region defined by a rotor and an adjacent stator. Advantageously, the or each stator and the or each rotor in such a reactor describes at least a part of the curved wall of a right circular cylinder, the rotor(s) and stator(s) being coaxial with each

other and, in the preferred case where the casing also has the general form of a right circular cylinder, with the casing.

Where there is more than one stator and or more than one rotor, there will normally be more than one polymerization region according to the invention. In the last-mentioned case, it will normally be desirable for one or more of the stator(s) and rotor(s) to have apertures and/or discontinuities therein so that the polymerization mixture, or components thereof, can readily pass from one region to another. Thus, for example, a rotor or stator may have a plurality of circular apertures therethrough, or may comprise a circumferentially continuous portion from which a plurality of wall portions extend in a generally axial direction to give a generally cylindrical surface with discontinuities therein.

An advantageous reactor as described above may be provided with one or more inlets and outlets such that the polymerization mixture, or components thereof, can be introduced in an axial direction to the centre of the rotor/stator arrangement and, after passing radially outwards through the rotor/stator arrangement, can be withdrawn from a zone between the said arrangement and the casing, or from a zone, for example, a post-reaction zone, downstream of the said zone. The rotor advantageously acts as a pump to draw materials fed axially into the reactor to the centre of the rotor/stator arrangement, and also subjects the materials to centrifugal forces causing them to move radially outwards through the rotor/stator arrangement. A reactor of this type is very suitable for use in carrying out polymerization reactions in a continuous manner. A rotor which causes or assists movement of fluids within the reactor may of course be used in reactors other than the especially advantageous reactor described above.

For any given polymerization reaction, the reaction time required to give optimum results will depend, inter alia, on the nature of the polymerization mixture and the temperature, and can be ascertained by routine experiment. If the polymerization time is too low, yields may be undesirably low, while if the time is too high, unwanted reactions may occur.

Some reaction of the compounds of the polymerization mixture used in accordance with the invention may occur other than in the polymerization zone (the region/thin film) used in accordance with the invention. Thus, for example, the compounds of the polymerization mixture may be mixed before being

introduced into the said region thin film, and some reaction may take place at that stage, or in a post-reaction zone (for example, a "soaking" zone) downstream of the polymerization zone used in accordance with the invention. Whether or not reaction occurs elsewhere, advantageously a major part of each of the components of the mixture is treated in a polymerization zone used in accordance with the invention. Preferably at least 75 mass% of the polymerization mixture is treated in the said polymerization zone, especially at least 85 mass%, and particularly at least 95 mass%. In the most preferred case, substantially all of the polymerization mixture is treated in the said zone. Thus the arrangements of inlet(s) and outlet(s) in any given reactor, and the internal design of the reactor, are preferably such that, in passing through the reactor, the polymerization mixture is constrained to pass through the polymerization zone.

The invention further provides the use of apparatus comprising an outer housing and a rotor within the housing, the housing and the rotor having opposed adjacent surfaces defining a reaction region, in the preparation of a homo or inteipolymer comprising units derived from at least one olefinically unsaturated hydrocarbon, the peripheral speed of the rotor preferably being at least 1 m/sec. In particular, the apparatus finds use where the polymerization mixture comprises components in different phases.

Polymers prepared in accordance with this invention are particularly useful as a feedstock for the production of lubricating oil additives, including dispersants. One class of useful dispersants comprises hydrocarbyl-substituted mono- and dicarboxylic acids and their derivatives, for example, esters and anhydrides, which can be made by reaction of the polymer with a monounsaturated mono- or dicarboxylic acid or a derivative thereof.

Any suitable process may be used for reacting the olefin polymer with the unsaturated carboxylic acid or derivative thereof. For example, the olefin polymer and the carboxylic acid or derivative may simply be heated together as disclosed in U.S. Patents Nos. 3,361 ,673 and 3,401 ,118 to cause a thermal "ene" reaction to take place. Alternatively, the olefin polymer can be first be halogenated, for example, chlorinated or brominated to about 1 to 8 wt.%, preferably 3 to 7 wt.% chlorine, or bromine, based on the weight of polymer, by passing the chlorine or bromine through the polyolefin at an elevated temperature. The halogenated polymer may then be reacted with sufficient unsaturated acid or derivative so the

product obtained will contain the desired number of moles of the unsaturated acid or derivative per mole of the halogenated polymer. Processes of this general type are taught in U.S. Patents Nos. 3,087,936, 3,172,892, 3,272,746 and others.

Alternatively, the olefin polymer, and the unsaturated acid or derivative are mixed and heated while adding chlorine to the hot material. Processes of this type are disclosed in U.S. Nos. Patents 3,215,707, 3,231,587, 3,912,764, 4,110,349, and in U.K. 1,440,219.

By the use of halogen, about 65 to 95 wt.% of the poly olefin, e.g. polyisobutyiene will normally react with a dicarboxylic acid or derivative. Upon carrying out a thermal reaction without the use of halogen or a catalyst, then usually only about 50 to 75 wt.% of the polyisobutyiene will react. Chlorination helps increase the reactivity.

In the manufacture of a carboxylic dispersant, at least one hydrocarbyl-substituted carboxylic acid material is advantageously mixed with, for example, at least one substance selected from amines, alcohols, including polyols, and aminoaicohols.

Suitable amines include monoamines or polyamines having up to about 30 carbon atoms, having at least one primary or secondary amino group, for example, the alkylene polyamines, particularly the ethylene polyamines, the, polyoxyalkylene amines, aromatic and cycloaliphatic amines, hydroxyamines, and mono-aliphatic and di-aliphatic substituted amines.

Useful dispersants may also be formed by reacting a monohydric or poryhydric alcohol with a hydrocarbyl succinic anhydride or diacid, preferred materials being derived from polyols having 2 to 6 OH groups and containing up to about 20 carbon atoms, for example, the alkane polyols and alkylene glycols. Also suitable are the polyoxyalkylene alcohols, for example, polyoxyethylene alcohols and polyoxypropylene alcohols, monohydric and polyhydric phenols and naphthols. ether alcohols and amino alcohols.

Borated derivatives of the foregoing dispersants are also useful, especially berated nitrogen-containing dispersants resulting from boration with boron oxide, boron halide, boron acids and esters. Metals and metal-containing compounds can also form useful dispersants. These are compounds capable of forming salts

with the hydrocarbyl succinic anhydride or acid. Suitable metals include metals such as the alkali metals, alkaline earth metals, zinc, cadmium, lead, cobalt, nickel, copper, iron, chromium, and magnesium. Metal derivatives, for example, oxides, carboxylates, halides, phosphates, sulphates, carbonates and hydroxides may be used where appropriate.

Also useful are Mannich Base condensate dispersants wherein the polymers prepared according to this invention are reacted with a hydroxy-substituted aromatic compound (e.g. phenol) in an alkylation reaction to form a polybutene- substituted hydroxyaromatic compound. This polybutene-substituted hydroxyaromatic compound can then be condensed in a Mannich Base reaction with an amine (e.g. any of the mono- or polyamines described above) and an aldehyde (e.g. formaldehyde). Such alkylation and Mannich Base reactions can be carried out using any suitable alkylation and Mannich base condensation methods.

Lubricating oil compositions will usually contain dispersants in amounts of from about 1 to 15 wt.% based on the overall weight of the composition. Dispersants are conveniently packaged and dispensed in the form of solution concentrates containing about 20 to 50 wt.% dispersant in mineral oils.

Polymers prepared in accordance with this invention may also be useful as a feedstock for the production of lubricating oil detergents. Such detergents include the metal salts of alkyaryl sulphonic acids, alkyl phenols, sulphurized alkyl phenols, alkyl salicylates, alkyl naphthenates, and other oil soluble mono- and di¬ carboxylic acids, wherein the detergent contains at least one alkyl group comprising a polymer corresponding to a polymer produced in the process of this invention. Usually these metal-containing detergents are used in lubricating oil in amounts of about 0.01 to 10 e.g. 0.1 to 5 wt.% based on the weight of the total lubricating composition. Marine diesel lubricating oils typically employ such metal-containing detergents (which are also sometimes termed "metal rust inhibitors") in amounts of up to about 20 wt.%.

Preferred detergent materials comprise oil-soluble compounds, for example metal salts of hydrocarbon sulphonic acids, prepared from aromatic hydrocarbons which have been alkylated with a polymer prepared according to this invention. The aromatic hydrocarbons from which the alkyl-substituted aromatic hydrocarbons

can be derived include benzene, toluene, xylene, naphthalene, diphenyl and the halogen derivatives, for example, chlorobenzene, chlorotoluene and chloronaphthalene. The alkylated aromatic compounds can then, for example, be sulphonated and converted to the metal salt. If desired, these alkyl-substituted aromatic hydrocarbons, containing alkyi-groups derived from the polymers prepared according to this invention, can be admixed with other alkyl-substituted aromatic hydrocarbons such that the sulphonation step is performed upon a mixture of alkyl-substituted aromatic hydrocarbons. Such other conventional alkyl-substituted aromatic hydrocarbons include those obtained from the fractionation of petroleum by distillation and or extraction.

The precise manner in which alkylation of an aromatic hydrocarbon is carried out is not critical, and any suitable alkylation process can be employed. The following discussion will illustrate alkylation employing benzene as the aromatic hydrocarbon, although it will be understood that any convenient aromatic hydrocarbon can also be employed.

Alkylation is generally carried out in the presence of a Friedel-Crafts type catalyst at temperatures in the range of from about -10 to 75°C, e.g. at 5°C, for times of from 5 to 60 minutes, e.g. 10 to 20 minutes. Suitable catalysts include, for example, AICI3, HF, BF3 and AIBr3, polyphosphoric acid, H2SO4 and aluminium chloride hydrocarbon complexes. Aluminium chloride is the preferred catalyst, and may be either fresh AICI3 or spent AICI3 sludge from a previous alkylation step, fortified by the addition of from 5 to 20 wt.% fresh AlCb.

It is generally desirable to maintain in the reaction mixture a volume ratio of benzene to polymer of at least 3:1 , e.g. 5:1 , although ratios of up to 20:1 may be used.

Although temperatures during the alkylation with AICI ₃ can range as high as 60°C, it is preferred to use temperatures of between about -5 to 30°C. Weight ratios of polymer to catalyst are typically in the range of about 30:1 to 7:1. Additionally, in the case of AICI3, an activator, for example, HCI can be added in an amount of from 15 to 40 wt.% based on the AICI3.

If a liquid HF catalyst is used for alkylation, it is preferred to use an HF-to- hydrocarbon reactants volume ratio of 0.1 :1 to 1.0:1 and temperatures in the

range of from 0 to 20°C. The concentration of this catalyst can range from 85 to 100 wt.% HF, its water content being maintained very low, e.g. no higher than 1 to 2 wt.%, the remainder being dissolved hydrocarbon material.

The alkylated fraction is recovered from the alkylation reaction mass may be sulphonated, if desired, in any suitable manner, e.g. by contact with an excess of concentrated sulphuric acid, oleum, CISO3H, or sulphur trioxide. The sulphonation can be carried out at temperatures up to about 60°C. Acid up to about 100 wt.% concentration can be employed, preferably oleum containing up to e.g. 20 wt.% or more SO3. With higher acid concentrations, lower reaction times are required, e.g. about 3 to 4 hours with 98 wt.% acid, about 2 hours with 100 wt.% acid, and preferably from about 0.5 to 1.0 hour with oleum. Volume ratios of sulphuric acid to hydrocarbon can range from 0.8:1 to 1.25:1 , with a 1 :1 ratio being suitable.

The sulphonated product can be recovered as described in U.S. Patent 3 367 865, the disclosure of which is hereby incorporated in its entirety.

The alkali and alkaline earth metal salts (e.g. the Ca, Mg, Ba, Na, K, Li etc. salts) of the sulphonated aromatic materials thereby produced can be prepared in any suitable manner, for example, using conventional techniques, for example, those described in U.S. Patent No. 3 367 865. Highly basic alkaline earth metal sulfonates are usually produced by heating a mixture comprising an oil-soluble alkaryl sulphonic acid, with an excess of alkaline earth metal compound above that required for complete neutralization of any sulfonic acid present and thereafter forming a dispersed carbonate complex by reacting the excess metal with carbon dioxide to provide the desired overbasing.

Additives made from polymers prepared in accordance with the invention are oil- soluble or (in common with certain of the other additives referred to below) are dissolvable in oil with the aid of a suitable solvent, or are stably dispersible materials. Oil-soluble, dissolvable, or stably dispersible as that terminology is used herein does not necessarily indicate that the materials are soluble, dissolvable, miscible, or capable of being suspended in oil in all proportions. It does mean, however, that the additives are, for instance, soluble or stably dispersible in oil to an extent sufficient to exert their intended effect in the environment in which the oil is employed. Moreover, the additional incoφoration

of other additives may also permit incorporation of higher levels of a particular additive, if desired.

Additives made from polymers prepared in accordance with the present invention can be incorporated into the oil in any convenient way. Thus, they can be added directly to the oil by dispersing or by dissolving them in the oil at the desired level of concentration, typically with the aid of a suitable solvent such, for example, as toluene, cyclohexane, or tetrahydrofuran. Such blending can occur at room temperature or an elevated temperature.

Additives made from polymers produced in accordance with the present invention may be useful in fuel oils or lubricating oils. The normally liquid fuel oils are generally derived from petroleum sources, for example, normally liquid petroleum distillate fuels, although they may include those produced synthetically by the Fischer-Tropsch and related processes, the processing of organic waste material or the processing of coal, lignite or shale rock. Such fuel compositions have varying boiling ranges, viscosities, cloud and pour points, according to their end use as is well known to those skilled in the art. Among such fuels are those commonly known as diesel fuels, distillate fuels, for example, gasoline, heating oils, residual fuels and bunker fuels, which are collectively referred to herein as fuel oils. The properties of such fuels are well known to those skilled in the art as illustrated, for example, by ASTM Specification D 396-73, available from the American Society for Testing Materials, 1916 Race Street, Philadelphia, Pennsylvania 19103.

Middle distillate fuel oils include distillates boiling from about 120 to 725°F (about 49 to 385°C) (e.g. 375 to 725°F (191 to 385°C)), including kerosene, diesel fuels, home heating fuel oil, jet fuels, etc., and most preferably whose 20% and 90% distillation points differ by less than 212°F (100°C), and/or whose 90% to final boiling point range is between about 20 and 50°F (about -7 and 10°C) and/or whose final boiling point is in the range of 600 to 700°F (about 316 to 371 °C).

Additives made from polymers prepared in accordance with the invention are particularly useful in lubricating oil compositions which employ a base oil in which the mixtures are dissolved or dispersed. Base oils with which the additives may be used include those suitable for use as crankcase lubricating oils for spark-

ignitθd and compression-ignited internal combustion engines, for example, automobile and truck engines, marine and railroad diesel engines.

Synthetic base oils include alkyl esters of dicarboxylic acids, po yglycols and alcohols; poly-α-olefins, polybutenes, alkyl benzenes, organic esters of phosphoric acids and polysilicone oils.

Natural base oils include mineral lubricating oils which may vary widely as to their crude source, for example, as to whether they are paraffinic, naphthenic, mixed, or paraffinic- naphthenic, as well as to the method used in their production, for example, distillation range, straight run or cracked, hydrofined, solvent extracted and the like.

More specifically, natural lubricating oil base stocks which can be used may be straight mineral lubricating oil or distillates derived from paraffinic, naphthenic, asphaltic, or mixed base crude oils. Alternatively, if desired, various blended oils may be employed as well as residual oils, particularly those from which asphaltic constituents have been removed. The oils may be refined by any suitable method, for example, using acid, alkali, and/or clay or other agents such, for example, as aluminium chloride, or they may be extracted oils produced, for example, by solvent extraction with solvents, for example, phenol, sulphur dioxide, furfural, dichlorodiethyl ether, nitrobenzene, or crotonaldehyde.

The lubricating oil base stock conveniently has a viscosity of about 2.5 to about 12 cSt (about 2.5 x 10 ⁶ to about 12 x 10" ⁶ m ² /s) and preferably about 2.5 to about 9 cSt. (about 2.5 x 10-6 _t o about 9 x 10-6 m ² /s) at 100°C.

An additive made from a polymer prepared in accordance with the present invention may be employed in a lubricating oil composition which comprises lubricating oil, typically in a major proportion, and the additive, typically in a minor proportion, for example, in a proportion as indicated below. Additional additives may be incoφorated in the composition to enable it to meet particular requirements. Examples of additives which may be included in lubricating oil compositions are viscosity index improvers, corrosion inhibitors, oxidation inhibitors, friction modifiers, dispersants, metal-containing detergents, anti- foaming agents, anti-wear agents, pour point depressants, and rust inhibitors.

Additives made from polymers prepared in accordance with the invention may where appropriate be used in lubricating oils other than engine oils.

Compositions when containing the above-mentioned additives are typically blended into the base oil in amounts which are effective to provide their normal function. Representative effective amounts of such additives for an automobile crankcase lubricant are:

* Mass% active ingredient based on the final oil-

When a plurality of additives are employed it may be desirable, although not essential, to prepare additive concentrates comprising the additives (the concentrate being referred to herein as an additive package) whereby several additives can be added simultaneously to the base oil to form the lubricating oil composition. Dissolution of the additive concentrate into the lubricating oil may be facilitated by solvents and by mixing accompanied with mild heating, but this is not essential. The concentrate or additive package will typically be formulated to contain the additive(s) in proper amounts to provide the desired concentration in the final formulation when the additive package is combined with a predetermined amount of base lubricant. Thus, one or more additives can be added to small amounts of base oil or other compatible solvents along with other desirable additives to form additive packages containing active ingredients in an amount, based on the additive package, of, for example, from about 2.5 to about 90 mass%, and preferably from about 5 to about 75 mass%, and most preferably from about 8 to about 50 mass% by weight, additives in the appropriate proportions with the remainder being base oil.

Three forms of reactor suitable for use in the process of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Fig. 1 is a schematic longitudinal section through one form of reactor suitable for use in accordance with the invention;

Fig. 2 is a cross-section through the reactor shown in Fig. 1 ;

Fig. 3 is a schematic vertical section through a preferred form of reactor suitable for use in accordance with the invention;

Fig. 4 is a cross-section through the reactor shown in Fig. 3;

Fig. 5 is a schematic vertical section through a modification of the reactor shown in Fig. 3; and

Fig. 6 is a cross-section through the reactor shown in Fig. 5.

Referring now to the drawings, the reactor shown in Figs. 1 and 2 comprises a housing 1 having the general form of a right circular cylinder, the housing being arranged with its longitudinal axis substantially horizontal. The housing, which is closed at each end, is provided at one end (the left hand end as seen in the drawings) with inlets 2,3 for components to be treated in the reactor and at the other end with an outlet 4 for products of the reaction.

Within the housing, and coaxial therewith, is a shaft 5 which can be caused to rotate by drive means 6 situated outside the housing. A plurality of blades 7 extend radially outwards from the shaft, the end of each blade closer to the shaft being fixed to the shaft so that the blades rotate with the shaft. The shaft and blades thus form a rotor, which rotates relative to the housing, the housing remaining stationary during use of the reactor.

The outer extremities of the blades are adjacent to the inner surface of the housings, such that the said extremities and surface define a polymerization region or zone. The width of the polymerization region may be, for example, 0.2 to 10 mm.

in use of the reactor, the shaft is caused to rotate at high speed, for example, 10,000 rpm. Such rotation causes a polymerization mixture or components thereof introduced through the inlets to form a thin film on the inner wall of the housing, polymerization taking place in this thin film. Material within the housing travels along the inner surface of the housing until it reaches the outlet, through which it is removed for any further processing that may be necessary.

Because a thin film is formed on the inner wall of the housing, the polymerization mixture is treated in accordance with the process of the invention. A further advantage of reactors in which the polymerization mixture forms a thin film on an outer housing is that the temperature of the mixture can be controlled by supplying heat to, or withdrawing it from, the housing.

Figs. 3 and 4 show a reactor particularly suitable for use in accordance with the invention. The reactor shown is particularly suitable for use when working on a laboratory scale, but may readily be adapted for larger scale operation.

The reactor comprises a casing 11 in the form of a right circular cylinder, the axis of the casing extending substantially vertically. The top and bottom of the casing are closed, the bottom being provided with inlets 12 and 13 for the polymerization mixture or components thereof and the top being provided with an outlet 14 for material that has passed through the reactor. When working on a large scale, it may be advantageous to use an arrangement in which the axis of the casing extends generally horizontally, as in Figs. 1 and 2.

Within the casing, and coaxial therewith, is a shaft 15, supported by a bearing, which can be caused to rotate by drive means (not shown) situated outside the casing. Attached to the lower end of the shaft is a rotor comprising a rotor disc 16 with an upwardly extending peripheral rotor flange 17. The disc is mounted on the shaft for rotational movement therewith, the shaft, disc and rotor flange thus forming a rotor. The disc is provided with three generally triangular apertures 18 therein, and the rotor flange has a plurality of circumferential openings 19 therein (most clearly seen in Fig. 4).

Also mounted in the casing is a stator comprising a stator disc 20 of larger diameter than the rotor disc 16, and two downwardly extending, circumferentially discontinuous, stator flanges 21 and 22, each of the said flanges being coaxial

with the rotor flange, which extends upwardly between the two stator flanges. Each of the stator flanges comprises a plurality of wall portions 24 extending downwardly from the stator disc such that there are openings 25 between the wall portions. As will be most clearly seen in Fig. 4, the outer surface of the rotor flange is adjacent to the inner surface of the outer stator flange 21 , and the inner surface of the rotor flange is adjacent to the outer surface of the inner stator flange 22, so that the rotor and stator define two annular polymerization regions, indicated by the reference numerals 26 and 27, in accordance with the invention.

The outer circumferential wall of the reactor shown in Figs. 3 and 4 may if desired be provided with a heating/cooling jacket (not shown).

In use of the reactor shown in Figs. 3 and 4, the shaft 15 is rotated and the polymerization mixture, or components thereof, is introduced through the inlets 12 and 13. The pumping action of the rotor causes the mixture or components to be drawn through the apertures 18 in the rotor disc 16 and thus into the central region of the rotor/stator arrangement. The mixture/components is or are then forced by the rotor to travel outwards in a generally radial direction, to pass through the inner stator flange, the rotor flange, and the outer stator flange to the zone 28 between the outer stator flange and the casing. In passing through the rotor and stator flanges, polymerization takes place in the annular reaction regions 26 and 27.

Material in the zone 28 passes upwardly through the casing (the upper part of the casing may, if desired, be used as a post-reaction zone), and removed via the outlet 14.

Figs. 5 and 6 show a modification of the reactor shown in Figs. 3 and 4. In the reactor shown in Figs. 5 and 6, the reactor also includes two opposed radially extending blades 30, each of which has a downwardly extending portion 31 providing a surface 32 adjacent to the inner surface of the inner stator flange 22. As shown in Figs. 5 and 6, the blades 30 and the rotor disc 16 are both mounted on the same shaft, but if desired they could be mounted on different shafts, one extending through the top of the reactor, and one extending through the bottom.

Although the arrangement shown in Figs. 5 and 6 has one rotor flange and two stator flanges, arrangements with additional rotor and stator flanges may be used

if desired, thus increasing the number of polymerization regions in accordance with the invention. Thus, for example, in some circumstances an arrangement with two upwardly extending rotor flanges and three downwardly extending stator flanges has been found to be advantageous.

In the reactor shown in Figs. 5 and 6, the apertures 18 shown in Figs. 3 and 4 are replaced by a plurality of circular apertures 33.