EP0485774A1 - Petrolium middle distillate with improved cold flowcharacteristics - Google Patents

Abstract

Petroleum middle distillates having improved cold-flow properties contain small quantities of A) conventional ethylene-base flow improvers and B) copolymers which consist a) of 10 to 90 mol% of one or more alkyl acrylates or alkyl methacrylates having C1- to C30-alkyl chains and b) of 5 to 60 mol% of one or more ethylenically unsaturated dicarboxylic acids or anhydrides thereof and c) of 5 to 60 mol% of one or more alkyl vinyl ethers having C18- to C28-alkyl side chains, the A/B weight ratio being 40 : 60 to 95 : 5. c

Description

The present invention relates to petroleum middle distillates which contain small amounts of a conventional flow improver based on ethylene and copolymers of ethylenically unsaturated carboxylic acid esters of long-chain n-alkanols with long-chain alkyl vinyl ethers and ethylenically unsaturated dicarboxylic acid derivatives which are characterized by improved flow properties in the cold.

Middle distillates such as gas oils, diesel oils or heating oils, which are obtained from petroleum by distillation, have different levels of paraffins depending on the origin of the crude oil and depending on the processing method in the refinery. The proportion of long-chain n-paraffins in particular determines the cold flow behavior of such distillates. Upon cooling, the n-paraffins separate out as platelet-shaped, interlocking crystals that build up a three-dimensional network (house of cards structure), in which large quantities of still liquid distillate are enclosed and immobilized. The crystallization of the n-paraffins is accompanied by a decrease in fluidity and an increase in viscosity. This makes it difficult to supply middle distillates to the combustion units, the failed paraffins clog upstream filters, so that in extreme cases the supply can completely stop.

It has long been known that by adding so-called flow improvers, the clogging of the filter can be counteracted at low temperatures. The additives nucleate the formation of many small instead of less large paraffin crystals. At the same time, they change their crystal modification so that the platelets described above do not form. The wax crystals formed in the presence of flow improvers are so small that they can pass through the filters or they build up a filter cake that is permeable to the still liquid portion of the middle distillate, so that trouble-free operation is ensured even at low temperatures.

Middle distillate cuts are increasingly appearing in refineries where the standard flow improvers are insufficient or even fail completely. This applies particularly to so-called high-cut oils, i.e. fractions with a high boiling point (SE> 370 ° C). However, boiling behavior is not the only criterion. So it happens that with two fractions with a similar boiling curve but different provinces of the base crude the standard flow improver responds well in one oil, but not in the other oil. The effectiveness of the flow improver is expressed indirectly according to DIN 51 428 by measuring the "Cold Filter Plugging Point" (CFPP).

Known per se as standard cold flow improvers are ethylene copolymers, especially copolymers of ethylene and unsaturated esters, such as those e.g. are described in DE-A-21 02 469 or EP-A-84 148.

In the art, however, new flow improvers or combinations are required which also show good effectiveness with the critical oils described above.

From DE-A-16 45 785 the use of polymers with unbranched, saturated side chains with at least 18 carbon atoms to lower the pour point of wax-containing heating oil is known. These are e.g. Homo- or copolymers of alkyl esters of unsaturated mono- or dicarboxylic acids as well as homo- or copolymers of various alkyl vinyl ethers. Also mentioned are: "Reaction products of copolymers of acid anhydrides of unsaturated dicarboxylic acids and monoolefins or other olefinically unsaturated compounds with an aliphatic amine containing a long hydrocarbon chain". Copolymers with monoolefins are preferred.

DE-A-25 31 234 recommends the addition of alternating copolymers containing maleic acid diamide or maleimide structures as stabilizers in mineral oils, i.e. the carboxyl groups are completely reacted with amines to give the diamides or imides.

According to US Pat. No. 3,506,625, reaction products of monoamines with maleic anhydride polymers to the corresponding imides are also described, wherein when using less than one mole of amine per mole of maleic anhydride unit, remaining carboxyl groups are converted into metal salts by neutralization. For the copolymerization with maleic anhydride, alkyl vinyl ether and monovinyl hydrocarbons are preferably used.

FR-A-2 592 658 describes mixtures of an ethylene polymer and a reaction product of a primary amine with a copolymer of, for example, alkyl acrylates and / or alkyl vinyl ethers, diisobutene and maleic anhydride and their use as an additive to middle distillates.

EP-A-360 419 describes middle distillates which contain polymers of vinyl ethers with hydrocarbon radicals of 1 to 17 carbon atoms. The following are among the comonomers: Called alkyl acrylates or methacrylates. In the examples, however, only polymers from alkyl vinyl ethers with up to 4 carbon atoms in the side chain are described. These C₁ to C₄ vinyl ethers are copolymerized with maleic or fumaric acid derivatives. Examples of copolymers with acrylic acid derivatives are not given. The claimed additives can be used together with other flow improvers.

EP-A-283 293 discloses the use of polymers with at least one amide group from a secondary amine and a carboxyl group as an additive to middle distillates. The polymers can include by copolymerization of unsaturated esters with maleic anhydride and subsequent reaction with the secondary amine. The unsaturated ester monomers include Dialkyl fumarates and vinyl acetate are described.

With regard to their effectiveness as a cold flow improver in middle distillates, however, these polymers still left something to be desired.

It was therefore the task to find additives to middle distillates that have a better effectiveness than cold flow improvers.

• a) zu 10 bis 90 mol-% aus einem oder mehreren Alkylacrylaten oder Alkylmethacrylaten mit C₁- bis C₃₀-Alkylketten und
• b) zu 5 bis 60 mol-% aus einer oder mehreren ethylenisch ungesättigten Dicarbonsäuren oder deren Anhydride und
• c) zu 5 bis 60 mol-% aus einem oder mehreren Alkylvinylethern mit C₁₈- bis C₂₈-Alkylseitenketten bestehen,

diese Forderung erfüllen.Surprisingly, it has now been found that petroleum middle distillates containing small amounts of A) known flow improvers based on ethylene and B) copolymers which

• a) 10 to 90 mol% of one or more alkyl acrylates or alkyl methacrylates with C₁ to C₃₀ alkyl chains and
• b) 5 to 60 mol% of one or more ethylenically unsaturated dicarboxylic acids or their anhydrides and
• c) consist of 5 to 60 mol% of one or more alkyl vinyl ethers with C₁₈ to C₂₈ alkyl side chains,

meet this requirement.

The copolymers B consist of 10 to 90 mol%, preferably 40 to 90 mol% and particularly preferably 60 to 90 mol% of alkyl (meth) acrylates, 5 to 60 mol%, preferably 5 to 40 mol -% and especially preferably 10 to 30 mol% of olefinically unsaturated dicarboxylic acids or their anhydrides, 5 to 60 mol%, preferably 5 to 40 mol% and particularly preferably 10 to 30 mol% of alkyl vinyl ethers.

The weight ratio of flow improver A to copolymer B is between 40:60 and 95: 5, preferably between 60:40 and 95: 5 and particularly preferably between 70:30 and 90:10.

The alkyl groups of the alkyl (meth) acrylates consist of 1 to 30, preferably 4 to 22 and particularly preferably 8 to 18 carbon atoms. They are preferably straight-chain and unbranched. However, up to 20% by weight of cyclic and / or branched portions can also be present.

Examples of particularly preferred alkyl (meth) acrylates are n-octyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, n-tetradecyl (meth) acrylate, n-hexadecyl (meth) acrylate and n-octadecyl (meth) acrylate and mixtures thereof.

Examples of ethylenically unsaturated dicarboxylic acids are maleic acid, tetrahydrophthalic acid, citraconic acid or itaconic acid or their anhydrides, fumaric acid and mixtures thereof. Maleic anhydride is preferred.

Examples of alkyl vinyl ethers are octadecyl vinyl ether, eicosyl vinyl ether, docosyl vinyl ether, tetracosyl vinyl ether, hexacosyl vinyl ether and octacosyl vinyl ether and mixtures thereof.

The copolymers B show synergistic effects together with flow improvers. Although the copolymers B alone show little or no flow-improving effect, the combination of A and B far exceeds the individual efficacies.

The carboxylic acid (anhydride) groups on the copolymer B can be completely or partially reacted with compounds containing amino or hydroxyl groups. This is not necessary to get the desired effectiveness. However, the effectiveness can be increased in some cases by the reaction and the solubility in the middle distillate or the compatibility with other components can be influenced favorably.

bevorzugt, in der R¹ einen geradkettigen oder verzweigten Alkylrest mit 1 bis 30, bevorzugt, 8 bis 26 und besonders bevorzugt 12 bis 24 Kohlenstoffatomen und R² Wasserstoff, Methyl oder R¹ bedeuten. Im einzelnen seien Ethylhexylamin, Octadecylamin, Oleylamin, Talgfettamin, N-Methyloctadecylamin und vorzugsweise Behenylamin, Dibehenylamin und hydriertes Ditalgfettamin genannt. Es können jedoch jedoch auch Alkylaryl- oder Arylamine sowie cyclische Amine, die gegebenenfalls ein Heteroatom besitzen, eingesetzt werden.Alkylamines are compounds containing amino groups

preferably in which R¹ is a straight-chain or branched alkyl radical having 1 to 30, preferably 8 to 26 and particularly preferably 12 to 24 carbon atoms and R² is hydrogen, methyl or R¹. Ethylhexylamine, octadecylamine, oleylamine, tallow fatty amine, N-methyloctadecylamine and preferably behenylamine, dibehenylamine and hydrogenated ditallow fatty amine may be mentioned in particular. However, alkylaryl or aryl amines and cyclic amines, which may have a hetero atom, can also be used.

Compounds of the formula in particular are compounds containing hydroxyl groups



R¹- (OR²) _n -OH



wherein R¹ is C₁ to C₃₀ alkyl, C₆ to C₁₂ aryl or C₁ to C₃₀ alkylaryl and R² is C₁ to C₄ alkyl and n is an integer from 0 to 30, preferably.

Examples of compounds containing hydroxyl groups include: alcohols such as 2-ethylhexanol, n-hexadecanol and n-octadecanol, alkylphenols such as iso-octylphenol, iso-nonylphenol and their reaction products with alkylene oxides such as ethylene oxide, propylene oxide and butylene oxide.

Examples of flow improvers A are the polymers already mentioned, described in DE-A-21 02 469 and EP-A-84 148, such as copolymers of ethylene with vinyl acetate, vinyl propionate, vinyl butyrate, vinyl pivalate or with esters of (meth) acrylic acid, which are derived from alkanols with 1 to 12 carbon atoms. Mixtures of several copolymers of ethylene and vinyl acetate (EP-A-261 951, additive A), copolymers of ethylene with α-olefins (EP-A-261 957, additive D) and those in DE-A-36 24 are also suitable 147 specified mixtures of terpolymers of ethylene, vinyl acetate and diisobutene with oxidized polyethylene wax. Copolymers of ethylene with vinyl acetate or vinyl propionate or ethylhexyl acrylate are particularly preferred.

The alkyl (meth) acrylates are easily accessible. They can be obtained by the known esterification processes. For example, a solution of (meth) acrylic acid and an alkanol or one is heated Mixing various alkanols in an organic solvent with the addition of the usual polymerization inhibitors, for example hydroquinone derivatives and esterification catalysts such as sulfuric acid, p-toluenesulfonic acid or acidic ion exchangers at the boil and removes the water of reaction formed by azeotropic distillation. Since vinyl ethers can polymerize cationically under acidic conditions or decompose in the presence of water and acid to form acetaldehyde, which interferes with the radical polymerization, the neutralization of the catalyst acid and excess (meth) acrylic acid by washing the ester solution with alkaline agents and water is necessary Production of the copolymers B required. Particularly pure esters can be obtained by distillation of the pre-cleaned ester solution.

Further possibilities for the preparation of the alkyl (meth) acrylates are the reaction of (meth) acrylic acid chloride or anhydride with the corresponding alkanols and the known transesterification reaction of lower (meth) acrylic acid esters with the corresponding C₈ to C₁₈ alkanols with the addition of acidic or basic catalysts and distillative removal of the lower alkanol. In these production processes, too, the ester should be worked up to such an extent that no acid is present.

The vinyl ethers can be obtained by known processes by reacting alkanols with acetaldehyde and subsequent elimination of water or by catalytic addition of acetylene to alkanols. Particularly pure monomers can also be obtained here by distillation. In the case of vinyl ethers with more than 20 to 22 carbon atoms in the alkyl part, the undecomposed distillation is technically difficult to carry out. In these cases, cleaning by filtration, extraction or recrystallization to remove the catalysts is recommended.

As a rule, it is advantageous to use the dicarboxylic acids in the form of the anhydrides, if available, in the copolymerization, e.g. Maleic anhydride, itaconic anhydride, citraconic anhydride and tetrahydrophthalic anhydride, since the anhydrides generally copolymerize better with the (meth) acrylates. The anhydride groups of the copolymers can then be reacted directly with compounds containing amino or hydroxyl groups.

The reaction of the polymers with amines takes place at temperatures of 50 to 250 ° C in the course of 0.3 to 30 hours. The amine is used in amounts of about one to two moles per mole of polymerized dicarboxylic anhydride, ie about 0.9 to 2.1 moles / mole. The use of larger or smaller amounts is possible, but has no advantage. The usage of 2 moles of amine per mole of anhydride leads to the amide / ammonium salt. This can be converted into the diamide by heating to 150 to 200 ° C with elimination of water. When using 1 mole of a primary amine per mole of anhydride, the resulting monoamide can be converted into the imide by heating to 150 to 250 ° C.

The reaction of the polymers with alcohols, alkylphenols or their alkoxylates also takes place at temperatures of 50 to 250 ° C. The alcohol or the phenol are used in amounts of 1 to 2 moles per mole of anhydride. If 1 mole of alcohol is used, the half-ester is formed; with 2 moles of alcohol, an esterification catalyst has to be added and the water of reaction has to be removed so that the diester can be formed completely.

The copolymers B can also be reacted both with an amino group-containing compound and with a hydroxyl group-containing compound. If the reaction is first carried out with an alcohol, then with an amine, an ester / ammonium salt is obtained, depending on the conditions, or an ester / amide at a higher temperature and removal of the water of reaction. If the reaction is first carried out with the amine, then with the alcohol, an ester / amide is obtained at the same time with removal of the water of reaction at a higher temperature.

Instead of the subsequent reaction of the carboxyl groups or of the dicarboxylic anhydride with the compounds containing amino or hydroxyl groups, it can sometimes be advantageous to prepare the monoamides, mono- or diesters, monoamide / monoesters etc. of the monomers and then to polymerize them directly in the polymerization. However, this is usually technically more complex, since e.g. Amines can also attach to the double bond of the dicarboxylic acids and then copolymerization is no longer possible.

The copolymers B are prepared by known batch or continuous polymerization processes such as bulk, suspension, precipitation or solution polymerization and initiation with customary radical donors such as acetylcyclohexanesulfonyl peroxide, diacetyl peroxidicarbonate, dicyclohexyl peroxidicarbonate, di-2-ethylhexyl peroxidicylate, 2,2'-dodecarboxylate, tert. -Azobis (4-methoxy-2,4-dimethylvaleronitrile), tert-butyl perpivalate, tert-butyl per-2-ethylhexanoate, tert-butyl permaleinate, 2,2'-azobis (isobutyronitrile), bis (tert-butyl peroxide ) -cyclohexane, tert-butyl peroxyisopropyl carbonate, tert-butyl peracetate, di-cumyl peroxide, di-tert-amyl peroxide, di-tert-butyl peroxide, p-menthane hydroperoxide, cumene hydroperoxide or tert-butyl hydroperoxide and mixtures among themselves. In general, these initiators are used in amounts of 0.1 to 20% by weight, preferably 0.2 to 15% by weight, based on the monomers.

The polymerization is generally carried out at temperatures of 40 to 400 ° C., preferably 70 to 300 ° C., the use of solvents with boiling temperatures below the polymerization temperature advantageously being carried out under pressure. The polymerization is conveniently carried out in the absence of air, i.e. if it is not possible to work under boiling conditions, e.g. carried out under nitrogen or carbon dioxide, since oxygen delays the polymerization. The reaction can be accelerated by using redox coinitiators such as benzoin, dimethylaniline, ascorbic acid and organically soluble complexes of heavy metals such as copper, cobalt, manganese, iron, nickel and chromium. The amounts usually used are 0.1 to 2000 ppm by weight, preferably 0.1 to 1000 ppm by weight. When choosing the initiator or initiator system, it is advisable to ensure at the chosen polymerization temperature that the half-life of the initiator or initiator system is less than 4 hours.

To achieve low molecular weight copolymers it is often advisable to work in the presence of regulators. Suitable regulators are, for example, allyl alcohols, such as 1-buten-3-ol, organic mercapto compounds, such as 2-mercaptoethanol, 2-mercaptopropanol, mercaptoacetic acid, mercaptopropionic acid, tert-butyl mercaptan, n-butyl mercaptan, n-octyl mercaptan, n-dodecyl mercaptan and tert.- Dodecyl mercaptan, which are generally used in amounts of 0.1 to 10 wt .-%.

Equipment suitable for the polymerization is e.g. Conventional stirred kettles with, for example, armature, blade, impeller or multi-stage impulse countercurrent stirrers and for the continuous production of stirred kettle cascades, tubular reactors and static mixers.

The simplest method of polymerization is bulk polymerization. The monomers are polymerized in the presence of an initiator and in the absence of solvents. Appropriately, all monomers are mixed in the desired composition and a small part, for example about 5 to 10%, is placed in the reactor, heated to the desired polymerization temperature with stirring and metered in the remaining monomer mixture and the initiator and, if appropriate, coinitiator and regulator within 1 to 10 hours, preferably 2 to 5 hours, evenly. It is expedient to meter in the initiator and the coinitiator separately in the form of solutions in a small amount of a suitable solvent. The copolymer can then be converted into the flow improver according to the invention directly in the melt or after absorption in a suitable solvent.

A continuous high-pressure process which permits space-time yields of 1 to 10 kg of polymer per liter of reactor and hour is also suitable for producing the desired copolymers. As a polymerization apparatus, e.g. a pressure vessel, a pressure vessel cascade, a pressure tube or a pressure vessel with a downstream reaction tube, which is provided with a static mixer, can be used. The monomers are preferably polymerized from (meth) acrylic esters, unsaturated dicarboxylic acids or their anhydrides and vinyl ethers in at least two polymerization zones connected in series. One reaction zone can consist of a pressure-tight vessel, the other of a heatable static mixer. You get sales of more than 99%. A copolymer of (meth) acrylic acid esters, maleic anhydride and octadecyl vinyl ether can be prepared, for example, by continuously feeding the monomers and a suitable initiator to a reactor or two reaction zones connected in series, for example a reactor cascade, and the reaction product after a residence time of 2 to 60 preferably from 5 to 30 minutes, at temperatures between 200 and 400 ° C. continuously discharged from the reaction zone. The polymerization is advantageously carried out at pressures of more than 1 bar, preferably between 1 and 200 bar. The copolymers obtained have solids contents of over 99%.

Another simple method for producing the copolymers B is solution polymerization. It is carried out in solvents in which the monomers and the copolymers formed are soluble. All solvents which fulfill this requirement and which do not react with the monomers are suitable for this. For example, these are toluene, xylene, ethylbenzene, cumene, high-boiling aromatic mixtures such as Solvesso® 100, 150 and 200, aliphatic and cycloaliphatic hydrocarbons such as n-hexane, cyclohexane, methylcyclohexane, n-octane, iso-octane, paraffin oils, Shellsol® TD , T and K, as well as tetrahydrofuran and dioxane, tetrahydrofuran and dioxane being particularly suitable for achieving low molecular weight copolymers. When carrying out the solution polymerization, it is expedient to initially introduce solvent and part of the monomer mixture (for example about 5 to 20%) and to meter in the rest of the monomer mixture with the initiator and, if appropriate, coinitiator, regulator and solvent. The monomers can also be metered in individually at different rates. This is recommended for monomers with very different reactivities and if the distribution is particularly uniform of the less reactive monomer in the polymer is desired. The less reactive monomer is metered in faster and the more reactive monomer more slowly. It is also possible to introduce the entire amount of a monomer, preferably the less reactive anhydride or vinyl ether, and to meter in only the (meth) acrylate. Finally, it is also possible to initially charge all the monomers and the solvent and to meter in only the initiator and, if appropriate, coinitiator and regulator (“batch” procedure). When this procedure is carried out on a larger scale, problems with heat dissipation can occur, so that this procedure should only be used at low concentrations of the monomers to be polymerized. The concentrations of the monomers to be polymerized are between 20 and 80% by weight, preferably 30 and 70% by weight. The solid copolymer can be easily obtained by evaporating the solvent. However, it is expedient to choose a solvent for the polymerization which is compatible with the middle distillate so that the polymer solution can be added directly to the middle distillate. Solution polymerization is the preferred form of preparation for the copolymers of (meth) acrylates and dicarboxylic acid (anhydrides).

There is a need in industry to provide the additives according to the invention, consisting of a flow improver A and a copolymer B, in an easily manageable form. For this purpose, polymers A and B should be present together in the form of a concentrate, since the use of 2 concentrates - one each for polymer A and polymer B - makes handling more difficult. Due to the possible incompatibility of polymers A and B, phase separation can occur when the two polymers are mixed in a common solvent. This can optionally be suppressed by suitable solvents and / or additives. Suitable are e.g. Alkanols such as iso-butanol, n-hexanol, 2-ethylhexanol, iso-decanol and their adducts with ethylene oxide, propylene oxide and / or butylene oxide, alkylphenols and their adducts with ethylene oxide, propylene oxide and / or butylene oxide as well as half esters or diesters of dicarboxylic acids with alkanols or (Oligo) alkylene oxide half ethers such as motto or dibutyl phthalate, mono- or di-2-ethylhexyl phthalate or di- (2-methoxyethyl) phthalate.

Another method of avoiding possible phase separation is to graft copolymer B at least in part onto the flow improver. Bulk or solution polymerization is preferably used for the grafting. The polymerization can be carried out according to the "batch" or feed procedure. In the "batch" procedure, the entire amount of flow improver A to be grafted is initially introduced together with the monomers and initiator and, if appropriate, coinitiator and Regulator dosed. In the feed procedure, the total amount of flow improver A to be grafted is optionally introduced together with some of the monomers and the rest of the monomers, initiator and, if appropriate, coinitiator and regulator are metered in.

As already mentioned, it is not necessary to graft the copolymer B onto the entire proportion of the flow improver A. For example, at a ratio A: B of 90:10, for reasons of space-time yield, the copolymer B will only be grafted to a proportion of 2 to 20% by weight of the total amount of A. With a ratio of A: B of 40:60, however, to a proportion of 30 to 100% by weight of the total amount of A.

It is also not necessary to graft the copolymer B completely onto part of the flow improver A. This is difficult anyway, since the graft yield generally does not reach 100%, so that in addition to graft copolymers and unconverted or admixed flow improver A, copolymer B may also be present in the concentrates described.

The K values (according to H. Fikentscher, Cellulosechemie, Volume 13, pages 58 to 64 and 71 to 74 (1932)), determined in 2% (w / v) xylene solution of the copolymers B, are between 10 and 50 , preferably between 10 and 40 and particularly preferably between 13 and 30. The particularly preferred range corresponds to molecular weights between approximately 5000 and 25,000 g / mol (number average values, determined by gel permeation chromatography against polystyrene standards).

The additives A and B according to the invention are added to the petroleum middle distillates in amounts of altogether 50 to 5000 ppm, preferably 100 to 2000 ppm.

The middle distillates according to the invention, containing small amounts of a flow improver A and a copolymer B, can, depending on the intended use, other additives or additives such as dispersants, anti-foam additives, corrosion inhibitors, antioxidants, dyes and others. contain.

The invention is illustrated by the following examples:

Preparation of the copolymers B according to the invention example 1

24.5 g of vinyl octadecyl ether, 8.1 g of maleic anhydride, 20 g of lauryl acrylate (n-alkylacrylate mixture, prepared from a commercially available fatty alcohol mixture consisting of a maximum of 1.5% by weight) were placed in a reactor equipped with a stirrer, heater and feed device .-% n-decanol, 51 to 57 wt.% n-dodecanol, 41 to 47 wt.% n-tetradecanol and max. 1.5 wt.% n-hexadecanol) and 79 g Solvesso® 150 (high-boiling Aromatic mixture from Esso) heated to 100 ° C. in a gentle stream of nitrogen with stirring and 147.4 g of lauryl acrylate in 76 g of Solvesso® 150 were metered in uniformly over the course of 2 hours. At the same time, a solution of 0.6 g of tert-butyl per-2-ethylhexanoate in 30.0 g of Solvesso® 150 was metered in uniformly over the course of 4 hours. A solution of 0.2 g of tert-butyl per-2-ethylhexanoate in 15 g of Solvesso® 150 was then added and the mixture was heated at 100 ° C. for a further hour. A clear, yellowish, approximately 50% by weight solution was obtained. The K value of the polymer was 16.9; the molar ratio of acrylate to maleic anhydride to vinyl ether is approximately 80:10:10.

Example 2

In a reactor according to Example 1, 167.4 g of lauryl acrylate, 8.1 g of maleic anhydride, 24.5 g of vinyl octadecyl ether and 163 g of Solvesso® 150 were heated to 100 ° C. in a gentle stream of nitrogen, with stirring, and a solution of 0. 6 g of tert-butyl per-2-ethylhexanoate in 30 g of Solvesso® 150 are evenly metered in. A solution of 0.2 g of tert-butyl per-2-ethylhexanoate in 7 g of Solvesso® 150 was then added and the mixture was reheated at 100 ° C. for one hour. A clear, yellowish, approximately 50% by weight polymer solution was obtained. The K value of the polymer was 18.9; the molar ratio of acrylate to maleic anhydride to vinyl ether is approximately 80:10:10.

Example 3

As in Example 2, but instead of Solvesso® 150, a high-boiling n- and iso-paraffin mixture from Shell (Shellsol® K) was used as the solvent.

A clear, light yellow, viscous, about 50% by weight polymer solution was obtained. The K value of the polymer was 30.6; the molar ratio of acrylate to maleic anhydride to vinyl ether is approximately 80:10:10.

Example 4

As example 2, but with 65.8 g of vinyl octadecyl ether, 21.7 g of maleic anhydride and 112.5 g of lauryl acrylate.

A clear, yellowish, about 50% by weight solution was obtained. The K value of the polymer was 17.3; the molar ratio of acrylate to maleic anhydride to vinyl ether is approximately 50:25:25.

Example 5

In a reactor according to Example 1 was 104.4 g of a C₁₈- to C₂₂-alkyl vinyl ether (made from a commercially available fatty alcohol mixture consisting of a maximum of 41 to 43 wt .-% n-octadecanol, 9 to 13 wt .-% n-eicosanol , 43 to 46% by weight of n-docosanol), 29.8 g of maleic anhydride and 185 g of Shellsol® K in a gentle stream of nitrogen with stirring to 100 ° C. and heated with 50 g of a solution of 375 g of lauryl acrylate in 202 g of Shellsol® K added and the rest of the solution metered in evenly within 2 hours. At the same time, a solution of 1.5 g of tert-butyl per-2-ethylhexanoate in 75.0 g of Shellsol® K was metered in uniformly over the course of 4 hours. A solution of 0.5 g of tert-butyl per-2-ethylhexanoate in 37.5 g of Solvesso® 150 was then added and the mixture was heated at 100 ° C. for a further hour. A clear, yellowish, approximately 50% by weight solution was obtained. The K value of the polymer was 20.3; the molar ratio of acrylate to maleic anhydride to vinyl ether is about 70:15:15.

Example 6

As in Example 5, but instead of lauryl acrylate, an n-alkyl acrylate mixture, prepared from a commercially available fatty alcohol mixture of the following composition, was used:
5 to 8 wt.% N-octanol, 5 to 7 wt.% N-decanol, 44 to 50 wt.% N-dodecanol, 14 to 20 wt.% N-tetradecanol, 8 to 10 wt. % n-hexadecanol and 8 to 12% by weight n-octadecanol.

A clear, light yellow, viscous, about 50% by weight polymer solution was obtained. The K value of the polymer was 18.5; the molar ratio of acrylate to maleic anhydride to vinyl ether is about 70:15:15.

Example 7

As Example 5, but 94 g of n-octadecyl vinyl ether were used instead of the C₁₈ to C₂₂ vinyl ether. A clear, light yellow, viscous, about 50% by weight polymer solution was obtained. The K value of the polymer was 20.3; the molar ratio of acrylate to maleic anhydride to vinyl ether is about 70:15:15.

Example 8

In a reactor according to Example 1, 207.5 g of vinyl octadecyl ether and 138 g of Shellsol® K were heated to 100 ° C. in a gentle stream of nitrogen with stirring, and a solution of 1.45 g of tert-butyl per-2-ethylhexanoate in 95 was added within 4 hours g Shellsol® K, a solution of 88.9 lauryl acrylate in 10 g Shellsol® K and 68.6 maleic anhydride in liquid form evenly metered in within 2 hours. The mixture was then reheated at 100 ° C. for one hour and diluted with 115 g of Solvesso® 150. A clear, yellowish, approximately 50% by weight polymer solution was obtained. The K value of the polymer was 21.5; the molar ratio of acrylate to maleic anhydride to vinyl ether is about 20:40:40.

Example 9

Grafting of lauryl acrylate, maleic anhydride and octadecyl vinyl ether onto a flow improver consisting of 60% by weight of ethylene and 40% by weight of vinyl propionate with an average molecular weight of approx. 2500 (determined by vapor pressure osmometry) = FI (A).

In a reactor according to Example 1, 170 g of the flow improver FI (A), 28.7 g of maleic anhydride, 51 g of octadecyl vinyl ether, 53.9 g of lauryl acrylate and 76 g of Solvesso® 150 were heated to 100 ° C. in a gentle stream of nitrogen with stirring. A mixture of 170 g lauryl acrylate, 36.2 g octadecyl vinyl ether and 23 g Solvesso® 150 was added in 2 hours and a solution of 1.02 g tert-butyl per-2-ethylhexanoate dissolved in 71.1 g Solvesso® 150 within evenly metered in over 4 hours. A solution of 0.34 g of tert-butyl per-2-ethylhexanoate in 25.5 g of Solvesso® 150 was then added, the mixture was heated for one hour and diluted with 314.5 g of Solvesso® 150. An approximately 50% by weight slightly cloudy polymer solution with a K value of 23.1 was obtained.

Examples 10 to 18

Reaction of the copolymers from Examples 1 to 8 with amines and alcohols
The reaction was carried out by adding the appropriate amount of the amine to the above polymer solutions and stirring at 100 ° C. until the anhydride band had disappeared in the infrared spectrum. The reaction with alcohols and their alkoxylates took place at 150 ° C. in 3 to 6 hours and was catalyzed with 1 mol% methanesulfonic acid. Example No. Polymer from example no. implemented with Moles per mole of MSA 10th 2nd O 1 11 1 A 2nd 12 5 A 1 13 7 T 1 14 7 T 2nd 15 7 AP-8 1 16 7 EH 1 17th 7 AT-11 1 18th 8th A 1

Example 19

93.3 g of the polymer solution from Example 9 were mixed with 105 g of FI (A) and 105 g of Solvesso® 150 at 60 ° C. A mixture which was cloudy at room temperature and was composed of a total of about 80 parts of flow improver FI (A) and 20 parts of copolymer B was obtained. The mixture is stable for more than 10 weeks at room temperature.

Example 20

A

handelsübliche Aminmischung eines hydrierten Ditalgfettamins mit folgender Kettenlängenverteilung: 1 % n-C₁₂, 4 % n-C₁₄, 31 % n-C₁₆, 59 % n-C₁₈, Rest ungesättigt

O

n-Octadecylamin

T

Talgfettalkohol (ca. 30 Gew.-% C₁₆ und 70 Gew.-% C₁₈)

AP-8

Lutensol AP 8 (Alkylphenol · 8 Mol Ethylenoxid)

AT-11

Lutensol AT 11 (C₁₆/C₁₈ Fettalkohol · 11 Mol Ethylenoxid)

25 g of a 50 wt .-% polymer solution according to Example 13 were stirred with 0.84 g of 2-ethylhexylamine and 0.84 g of Solvesso® 150 at 40 ° C for 30 minutes. In this example, the monoester is converted to the ester ammonium salt.

A

Commercial amine mixture of a hydrogenated ditallow fatty amine with the following chain length distribution: 1% n-C₁₂, 4% n-C₁₄, 31% n-C₁₆, 59% n-C₁₈, the rest unsaturated

O

n-octadecylamine

T

Tallow fatty alcohol (approx. 30% by weight C₁₆ and 70% by weight C₁₈)

AP-8

Lutensol AP 8 (alkylphenol · 8 mol ethylene oxide)

AT-11

Lutensol AT 11 (C₁₆ / C₁₈ fatty alcohol · 11 mol ethylene oxide)

Examples of use

FI(A)

Ethylen/Vinylpropionat (mit ca. 40 Gew.-% Vinylpropionat) mit einem mittleren Molekulargewicht von ca. 2500 (bestimmt durch Dampfdruckosmometrie)

FI(B)

Ethylen/Vinylacetat (mit ca. 30 Gew.-% Vinylacetat) mit einem mittleren Molekulargewicht von ca. 2500

The following mean:
FI flow improver, in particular

FI (A)

Ethylene / vinyl propionate (with approx. 40% by weight vinyl propionate) with an average molecular weight of approx. 2500 (determined by vapor pressure osmometry)

FI (B)

Ethylene / vinyl acetate (with approx. 30% by weight vinyl acetate) with an average molecular weight of approx. 2500

The flow improvers FI (A) and FI (B) are commercially available products, e.g. the Keroflux® brands from BASF.

Heating oils and diesel fuels in commercial West German refinery quality were used as middle distillates. They are referred to as middle distillate I, II, III and IV. Middle distillate I. II III IV Cloud point (° C) + 6 + 2 + 4th + 5 CFPP (° C) 0 - 3rd - 1 - 2nd Initial boiling point (° C) 155 175 169 174 20% boiling point (° C) 232 247 222 219 50% boiling point (° C) 280 285 262 272 90% boiling point (° C) 352 354 351 365 End of boiling point (° C) 382 375 381 385

Test method:

The "Cold Filter Plugging Point" (CFPP) was tested according to DIN 51 428. The results are summarized in the following table.

As the above examples show, the conventional flow improvers FI (A) and FI (B) only work insufficiently in the middle distillates. The sole addition of the copolymers according to the invention rather worsens the CFPP of the middle distillates. The synergistic effect of flow improvers and copolymers according to the invention is illustrated by Examples 6 to 28.

Claims (8)

Process for the production of petroleum distillates with improved flow properties in the cold, characterized in that small amounts of the petroleum distillates A) conventional ethylene based flow improver and B) copolymers that a) 10 to 90 mol% of one or more alkyl acrylates or alkyl methacrylates with C₁ to C₃₀ alkyl chains and b) 5 to 60 mol% of one or more ethylenically unsaturated dicarboxylic acids or their anhydrides and c) consist of 5 to 60 mol% of one or more alkyl vinyl ethers with C₁₈ to C₂₈ alkyl side chains admits
the weight ratio of A to B being 40 to 60 to 95 to 5. Process according to Claim 1, characterized in that copolymers B are added which consist of 40 to 90 mol% of the monomers mentioned under a) and 5 to 40 mol% each of the monomers mentioned under b) and c). A method according to claim 1, characterized in that copolymers B are added, which consist of C₄ to C₂₂ alkyl (meth) acrylates and maleic anhydride or itaconic anhydride and C₁₈ to C₂₈ alkyl vinyl ethers. Process according to Claim 1, characterized in that the alkyl substituents in the copolymers B are straight-chain and unbranched. Process according to Claim 1, characterized in that the dicarboxylic acids or their anhydrides in the copolymers B are reacted with compounds containing amino groups and / or compounds containing hydroxyl groups. A method according to claim 1, characterized in that copolymers of ethylene with vinyl acetate, vinyl propionate or ethylhexyl acrylate are added as conventional flow improvers. Process according to Claim 1, characterized in that copolymers are added which are grafted to 0 to 100% of the conventional flow improvers. Process according to Claim 1, characterized in that the flow improvers A and the copolymers B are added to the petroleum middle distillates together in proportions of 50 to 5000 ppm.