EP0209806A2 - Reaction products of polyalkenyl succinic acid imidoamine with tri- or tetracarbonic acids, and their use as lubricant additives - Google Patents

Abstract

Reaction products of A) polyalkenylsuccinic acid imidoamines of the formula I <IMAGE> in which R<1> is an aliphatic radical still containing at least one double bond and having an average molecular weight from 400 to 5000, and <2bL>N-R<2> is the radical of an aliphatic polyamine having 2 to 7 nitrogen atoms, to which one to two further polyalkenylsuccinic acid radicals can also be bound, under amidating conditions with B) a tri- or tetracarboxylic acid in a polyalkenylsuccinic acid radical:polycarboxylic acid molar ratio from 1:1 to 3:1 in the case of the tricarboxylic acid and 1:1 to 4:1 in the case of the tetracarboxylic acid.

Description

The invention relates to new lubricant oil additives suitable as "ashless dispersants" obtainable by reacting polyalkenyl amber imido amines with tri- or tetracarboxylic acids under amidating conditions.

Reaction products of polyalkenylsuccinic anhydride (PIBSA) with polyamines have been widely described in the literature and are widely used in practice as "ashless dispersants" in lubricating oils. In engine oils, these dispersants or HD (heavy duty) additives have the task of oil-insoluble combustion residues, which can be up to 10% by mass with diesel engine oils (e.g. soot, coke, lead salts with a size of 0.04 µm) and resin and asphalt-like oxidation products, which promote caking to solid particles with a size of 0.6 to 1.5 µm, to be kept in suspensions, thereby preventing deposits on metal surfaces, oil thickening and sludge deposits in the engine as well as corrosive wear by neutralizing acidic combustion products. Coke and varnish-like deposits stick the piston rings so that the combustion gases pass into the crankcase, the oil is heavily contaminated and piston loads can occur when the engine is under high load. Sludge discharges can clog the oil filter and oil holes and thus lead to a lack of lubricating oil and high wear. Acidic combustion products of the fuel lead to corrosion.

"Ashless dispersants" are ashless organic compounds that prevent flocculation or coagulation of colloidal particles. However, since the dispersibility is not sufficient to completely prevent deposits in the engine, a certain dissolving effect for paints and resins must be added.

The dispersant effect after absorption on the surface of dirt particles is apparently based on an electrostatic repulsion of the particles or a prevention of the mutual approach of these particles by reducing the intermolecular dispersion forces.

Although the known reaction products bring about a significant improvement in the lubricating properties, the dispersing properties after thermal aging were still inadequate.

The reaction of reaction products of polyalkenylsuccinimidoamines with dicarboxylic acids according to EP-A 00 72 645 has therefore already been proposed. Furthermore, DE-AS 19 33 896 describes the production of acylation products from the components alkenylsuccinic acid, polyamine and Polycarboxylic acid described, but first the amine component is acylated with the polycarboxylic acid and then reacted with the alkenyl succinic anhydride.

However, the reaction products obtained according to these patents have an insufficient dispersing action before and after thermal aging.

• A) Polyalkenylbernsteinsäureimidoaminen der Formel I
  
  in der R¹ einen noch mindestens eine Doppelbindung enthaltenden aliphatischen Rest mit einem Durchschnittsmolekulargewicht von 400 bis 5000 und
  
  den Rest eines aliphatischen Polyamins mit 2 bis 7 Stickstoffatomen bedeutet, an den noch ein bis zwei weitere Poly­alkenylbernsteinsäurereste gebunden sein können, unter amidierenden Bedingungen mit
• B) einer Tri- oder Tetracarbonsäure im Molverhältnis Polyalkenylbern­steinsäurerest zu Polycarbonsäure von 1:1 bis 3:1 im Falle der Tri­carbonsäure und von 1:1 bis 4:1 im Falle der Tetracarbonsäure.

The object was therefore to propose dispersing lubricating oil additives which do not have the disadvantages indicated. According to the invention, this object was surprisingly achieved with reaction products of

• A) Polyalkenylsuccinimidoamines of the formula I.
  
  in which R 1 contains an aliphatic radical with at least one double bond and an average molecular weight of 400 to 5000 and
  
  means the remainder of an aliphatic polyamine with 2 to 7 nitrogen atoms, to which one or two further polyalkenyl succinic acid residues can be bound, under amidating conditions with
• B) a tri- or tetracarboxylic acid in the molar ratio of polyalkenylsuccinic acid residue to polycarboxylic acid from 1: 1 to 3: 1 in the case of tricarboxylic acid and from 1: 1 to 4: 1 in the case of tetracarboxylic acid.

It is important for the effect of the reaction products that first the formation of polyalkenylsuccinimidoamine and then the reaction with polycarboxylic acids takes place, and not vice versa.

• I) in an sich bekannter Weise noch reaktive Doppelbindungen enthal­tende Polyolefine oder chlorierte Kohlenwasserstoffe mit dem Rest R¹ gemäß Formel mit Maleinsäureanhydrid umsetzt,
• II) das erhaltene substituierte Bernsteinsäureanhydrid mit dem Poly­amin im Molverhältnis von ungefähr 1:1 bis 1:0,3 zum Aminoimid (A) reagieren läßt und
• III) das Imidoamin A mit einer Tri- oder Tetracarbonsäure im Molver­hältnis eingesetztes Alkenylbernsteinsäureanhydrid zu Polycar­bonsäure 1:1 bis 1:3 im Falle der Tricarbonsäure und im Molver­hältnis 1:1 bis 1:4 im Falle der Tetracarbonsäure bei Tempera­turen von 150 bis 220°C umsetzt.

Accordingly, the invention also relates to a process for the preparation of reaction products of polyalkenylsuccinic acid aminoimides with tri- or tetracarboxylic acids in the order given, after which

• I) in a manner known per se, reacting polyolefins or chlorinated hydrocarbons which still contain reactive double bonds with the radical R 1 according to the formula with maleic anhydride,
• II) the substituted succinic anhydride obtained can react with the polyamine in a molar ratio of approximately 1: 1 to 1: 0.3 to the aminoimide (A) and
• III) the imidoamine A with a tri- or tetracarboxylic acid in a molar ratio of alkenylsuccinic anhydride to polycarboxylic acid used 1: 1 to 1: 3 in the case of tricarboxylic acid and in a molar ratio of 1: 1 to 1: 4 in the case of tetracarboxylic acid at temperatures of 150 to 220 ° C. implements.

These reaction conditions are chosen so that water elimination and amidation occur. Although the nature of the end products is not known in detail, it is believed that amides are formed in the reaction with the polycarboxylic acids, and the multiple carboxyl function of the polycarboxylic acid can give rise to both links to other molecules and intramolecular links.

The starting component polyalkenylsuccinic anhydride can in turn be prepared by known processes, such as those e.g. in U.S. Patents 30 87 936, 31 63 603, 31 72 892, 31 89 544, 32 19 666, 32 72 746, 32 88 714, 33 06 907, 33 31 776, 33 40 281, 33 41 542, 33 46 354, 33 74 174 and 33 81 022 are described.

Thus, the succinic anhydrides substituted by an essentially saturated aliphatic hydrocarbon residue, e.g. easily by reacting maleic anhydride with a high molecular weight olefin or a chlorinated hydrocarbon, e.g. a chlorinated polyolefin. The two reaction components are heated to temperatures of approximately 100 to 300 ° C., preferably 100 to 200 ° C. As explained in the aforementioned patents, a substituted succinic anhydride is obtained, the substituent of which is derived from the olefin or chlorinated hydrocarbon. The product can optionally be hydrogenated in a conventional manner to remove all or part of the remaining unsaturated bonds.

The olefinically unsaturated hydrocarbons used for this are mainly high molecular weight, essentially saturated petroleum fractions or essentially saturated polyolefins or corresponding chlorinated compounds with a molecular weight of 400 to 5000. The olefinically unsaturated hydrocarbon can contain oil-solubilizing branches, and also unsaturated within the general limits given below be. Polymers and chlorinated polymers which are derived from monoolefins having 2 to 30 carbon atoms are preferred. Polymers used with preference are derived from α-monoolefins, such as ethylene, propylene, butene-1, hexene-1, octene-1, 2-methylheptene-1, 3-cyclohexylbutene-1 and 2-methyl-5-propylhexene-1 and preferably isobutene. Polymers from olefins with a central double bond, such as butene-2, pentene-3 and octene-4, can also be used.

The copolymers of the α-monoolefins mentioned with one another and with other olefins as comonomers, such as aromatic olefins, cyclic olefins and polyolefins, can also serve as polyolefin residues. Such copolymers are e.g. by copolymerization of isobutene with styrene, isobutene with butadiene, propylene with isoprene, propylene with isobutene, ethylene with piperylene, isobutene with chloroprene, isobutene with p-methylstyrene, hexene-1 with hexadiene-1,3, octene-1 with hexene-1 , Hepten-1 with pentene-1, 3-methylbutene-1 with octene-1, 3,3-dimethylpentene-1 with hexene-1 and isobutene with styrene and piperylene.

Particularly suitable polymers are polypropylene, polyisobutene, copolymers of propylene and isobutene and the chlorination products of the polymers mentioned.

With regard to oil solubility and stability, the polymers used for the preparation of component A should be essentially aliphatic in nature and saturated, i.e. they should contain at least 80 and preferably 95% by weight of units derived from aliphatic monoolefins. They contain at most 5, preferably at most 2%, olefinic bonds, based on the total number of C-C bonds.

The chlorinated hydrocarbons and the olefinically unsaturated hydrocarbons which are used to prepare component A have an average molecular weight of 400 to 5000, in particular 700 to 5000.

Particularly suitable polyamines are aliphatic amines having 2 to 18, preferably 2 to 12 carbon atoms and 2 to 7 nitrogen atoms, these polyamines should contain at least 1 primary amino group.

Preferred amines are alkyl polyamines having 2 to 10 carbon atoms and 2 to 5 nitrogen atoms, which may also contain hydroxyl groups or ether oxygen.

Specifically, e.g. Ethylene diamine, diethylene triamine, triethylene tetramine, tetraethylene pentamine, tripropylene tetramine or hydroxyl-containing amines such as aminoethylethanolamine or mixtures of these amines into consideration. Residues from the distillative purification stages of the amines mentioned can advantageously also be used.

Aliphatic tri- and tetracarboxylic acids or mixtures thereof are suitable as polycarboxylic acids. Particularly advantageous results are achieved with citric acid, nitrilotriacetic acid and ethylenediaminetetraacetic acid.

In detail, the reaction of the polyalkenylsuccinimidoamines with the polycarboxylic acids according to the invention is carried out at temperatures of 150 to 220 ° C., preferably at 160 to 190 ° C. At these temperatures, water is split off and amide forms.

The reaction products according to the invention are preferably prepared in a one-pot reaction over 3 separate stages. For this purpose, the polyalkenylsuccinic anhydride is first prepared in a first step, this is reacted in a second step with the polyamine in a molar ratio of 1: 1 to 1: 0.3 in a manner known per se to give the polyalkenylsuccinimidoamine, and in a third step the reaction with the tri- or tetracarboxylic acid with elimination of water.

The reaction over all stages can take place without a solvent or preferably with solvents such as xylene, toluene, kerosene and in particular in a mineral oil. The end product is then dissolved in the mineral oil; this solution can then be used directly as a lubricating oil additive.

The dispersing effect of the new reaction products during thermal aging is retained for significantly longer and these products accordingly have superior properties compared to the closest comparable products.

example 1 Manufacturing example

To 239.5 g of polyisobutenyl succinic anhydride (acid number 70.2) and 166.4 g of mineral oil (solvent raffinate, viscosity at 100 ° C.: 10.45 mm² / s), 15.8 g of a mixture of 45% by weight were added at 80 ° C. % Aminoethylethanolamine and 55 wt .-% polyamines with an average of 6 carbon atoms and 4 nitrogen atoms were added dropwise. The mixture was heated slowly to 160 ° C. under nitrogen and stirred at this temperature for 4 hours. After treatment in a water jet vacuum for 1 hour, 416 g of polyisobutenylsuccinimidoamine were obtained. The mixture was then allowed to cool to 80 ° C. and 23.8 g (0.124 mol) of nitrilotriacetic acid and 11.4 g of mineral oil (solvent raffinate, viscosity at 100 ° C.: 10.45 mm 2 per second) were added, and the mixture was slowly heated to 160 ° C. and kept the mixture at this temperature for 6 hours. After another 2-hour treatment in a water jet vacuum at 160 ° C., 446 g of a 60% solution of the product to be used as a lubricating oil additive in mineral oil were obtained.

The implementations according to Table 1 were carried out according to this procedure

Manufacturing examples

Application testing and discussion of the properties

The assessment of the dispersing action is carried out according to the dot method as described by A. Schilling in "Les Huiles pour Moteurs et le Graissage des Moteurs, Vol. 1, 1962, pages 89-90 f. For this purpose, 5% active substance in a Mixture of 3 parts of a neutral solvent refinate 150 and a part of used oil produced The soot-containing used oil came from a MWM-KD 12E motor, which was operated according to DIN 51363, parts 1 and 2. The speed in this operation was n = 2000 U / min, the power 6 KW. At operating temperature, the temperature of the cooling water inlet was 80 ° C, that of the outlet and oil 85 ° C. The soot number of the exhaust gas according to Bosch was 4, the test duration was 50 hours. The engine oil consisted of 78.8 parts a neutral solvent raffinate 150, 19.7 parts of a neutral solvent raffinate 500 and 1.5 parts of a viscosity index improver based on a randomly constructed, hydrogenated butadiene / styrene copolymer.

The thermal and hydrolytic loads to which the dispersant-containing oils were subjected before the spot test are described in Lubricant Additives 1978 by B. Demoures et al on page 6, examples 1 to 5.

According to this method, the dispersing effect is by definition a value between the blank value and the thousand, which is the average of 5 results from different tests. Table 2 summarizes the assessment of the dispersing effect of the products from Examples 1 to 10.

Approved good dispersants, which are currently commercially available as part of additive packages, have values between 500 and 650. Compared to market products, the compounds according to the invention are in the upper range of activity or above and therefore have a partial effect. Expect significantly lower dosage with the same effectiveness as a dispersant.

Comparative examples

• A) If the components given in Examples 1 to 10 are used in the proportions given there, the order of the reaction is changed, however. first reaction of the polyacid with the polyamine and further reaction of the reaction product with polyisobutylene succinic anhydride, products are obtained in all cases which are insoluble in the test oil, so that their dispersing action cannot be tested.
• B) Example 3 according to DE-AS 19 33 896 was reworked as described there. The product obtained in this way had a lower dispersing effect in accordance with Table 3.
• C) Here, example 1 of EP 72645 was reworked and the dispersing action was determined in accordance with the spot test.
• D) Example 2 of EP 72645 gave the following dispersing effect according to the spot test:

Claims (5)

1. Implementation products from A) Polyalkenylsuccinimidoamines of the formula I.

in which R 1 contains an aliphatic radical with at least one double bond and an average molecular weight of 400 to 5000 and

means the remainder of an aliphatic polyamine with 2 to 7 nitrogen atoms, to which one or two further polyalkenyl succinic acid residues can be bound, under amidating conditions with B) a tri- or tetracarboxylic acid in the molar ratio of polyalkenylsuccinic acid residue to polycarboxylic acid from 1: 1 to 3: 1 in the case of tricarboxylic acid and from 1: 1 to 4: 1 in the case of tetracarboxylic acid. 2. Reaction products according to claim 1, characterized in that R¹ is a polyisobutenyl radical with an average molecular weight of 700 to 5000 and R² is the remainder of a di- to pentaamine having 2 to 18 carbon atoms. 3. Reaction products according to claims 1 and 2, characterized in that the tri- or tetracarboxylic acids are citric acid, nitrilotriacetic acid and ethylenediaminetetraacetic acid. 4. A process for the preparation of reaction products of Polyalkenylbernsteinsäureimidoaminen with tri- or tetra-carboxylic acids according to claim 1 characterized in that in the stated order I) reacting polyolefins or chlorinated hydrocarbons containing reactive double bonds with the radical R¹, where R¹ has the meaning given in claim 1, in a manner known per se with maleic anhydride, II) the substituted succinic anhydride obtained can react with the polyamine in a molar ratio of approximately 1: 1 to 1: 0.3 to the imidoamine (A) and III) the imidoamine A with a tri- or tetracarboxylic acid in a molar ratio of alkenylsuccinic anhydride to polycarboxylic acid used 1: 1 to 1: 3 in the case of tricarboxylic acid and in a molar ratio of 1: 1 to 1: 4 in the case of tetracarboxylic acid at temperatures of 150 to 220 ° C. implements. 5. Use of the reaction products according to claims 1 to 4 as lubricating oil additives.