CA2055418A1

CA2055418A1 - Middle distillates of crude oil having improved cold flow properties

Info

Publication number: CA2055418A1
Application number: CA002055418A
Authority: CA
Inventors: Gerd Konrad; Klaus Barthold; Hans-Juergen Raubenheimer; Bernd Wenderoth; Erich Schwartz; Heinrich Hartmann
Original assignee: Individual
Current assignee: BASF SE
Priority date: 1990-11-14
Filing date: 1991-11-13
Publication date: 1992-05-15
Also published as: ES2068464T3; DE59104601D1; FI915126A0; EP0486836A1; NO914443D0; ATE118529T1; EP0486836B1; FI105824B; NO304077B1; NO914443L; DE4036227A1; FI915126A

Abstract

ABSTRACT OF THE DISCLOSURE

Crude oil middle distillates with improved cold flow properties, containing small amounts of A. conventional flow improver on an ethylene base, and B. copolymers which consist to at least 70% by weight of one or a plurality of monomers of Formula I as well as II, R1 H2C=C-COOR2 and H2C=CH-O-R3 (I) (II) where R1 is hydrogen or methyl, R2 is a C8 to C18 alkyl, and R3 is a C18 to C28 alkyl and where the weight ratio of A to B is from 40 to 60 to 95 to 5.

Description

2 ~ 1 8 MIDDLE DISTILLATES OF CRUDE OIL HAVING IMPROVED
COLD FLOW PROPERTIES

FIELU OF THE INVENTION

The present invention relates to middle distillates of crude oil containing small amounts of a conventional flow impxover on an ethylene base and copolymers of ethylenically unsaturated carboxylic acid esters of long-chain n-alcanols with long-chain alkylvinyl ethers, which are distinguished by improved cold flow properties.

BACKGROUND OF THE INVENTION

Middle distillates, such as gas oil, Diesel oil or heating oil, which are obtained from crude oil by distillation have, depending on the source of the crude oil and depending on the type of processing in the refinery, difPerent paraffin contents. The proportion of long-chain n-paraffins in particu]ar determines the cold flow properties of such distillates. During cooling, the n-paraffins are separated in the form of platelet-iike interlaced crystals which build up into a three-dimensiona~ network ~house of cards structure~, where large amounts of still .Iquid distillate are locked up and immobilized. A decrease of flowability and an increase of the viscosity occurs parallel with the crystallization of the n-paraffins. The supply of middle distillates to the combustion means is made more difficult because of this. The precipitated paraffins plug filters ahead of the~ combustion means so that in extreme cases it is possible that the entire supply is stopped.
It has been known for a long time that the plugging of the filters at low temperatures can be overcome by the addition of so-called flow improvers. By means o~ the formation of nuclei, the : .. ,........................ :.- ,:., .':

additives cause the formation of many small paraffin crystals in place of a few large ones. ~t the same time they change their crystal modification, so that there is no formation of the above described platelets. The paraffin crystals formed in the presence of flow improvers are so small that they can pass through the filters, or they build up into a filter cake which is permeable to the still liquid portion of the middle distillatQ, so that operation free of disruption is assured even at low temperatures.
Middle distillate cuts are appearing in increasing amounts in the refineries, where the standard flow improvers do not have a sufficient effect or even fail completely. This applies particularly to so-called top draw oil, i.e. fractions with a high final boiling point (F.B.P. > 370C). However, the boiling properties are not the criteria. It may occur in connection with two fractions with similar boiling point curves but dissimilar provenance of the basic crude oil, that the standard flow improver works well with one oil, but not with the other. In accordance with DIN 51 428, the effectiveness of the flow ~mprover is indirectly expressed by measuring the cold filter plugging points (CFPP).
Ethylene copolymers, known per se, mainly copolymers of ethylene and unsaturated esters such as described in German Patent Disclosure DE-~-21 02 469 or European Patent Disclosure EP-A-84 148, are used as standard cold flow improvers.
However, the technology requires new flow improvers which also show good effectiveness in connection with the above described critical oils.
The use of polymers with linear, saturat~d side chains with at least 18 carbon atoms for reducing the flow point of paraffin-containing heating oil is known from German Pat~nt Disclosure DE-A-16 45 785. These are, for example, homo- or copolymers of 2 ~

alkylesters of unsaturated mono- or dicarboxylic acids as well as homo- or copolymers o~ various alkylvinylethers.
German Patent Disclosure DE-A-20 ~7 448 ~escribes the addition of a mixture consisting of polyvinylethers and ethylene-vinylacetate-copolymers to paraffin based crude oils.
Middle distillates are described in ~uropean Patent Disclosure EP-A-360 419, which contain polymers of vinylethers with hydrocarbon radicals o~ 1 to 17 carbon atoms. Alkylacrylates or -methacrylates, among others, are disclosed as co-monomers.
However, the examples only describe polymers of alkylvinylethers with up to four carbon atoms in the side chain. These C1- to C4-vinylethers are copolymerized with derivatives of maleic or ~umaric acid. No examples of copolymers with d~rivatives of acrylic acid are provided. The claimed additive-; can be used in conjunction with other flow improvers.
However, these polymers leave a lot to b6 desired in regard to their effectiveness as cold flow improvers for middle distillates.
For these reasons the problem arose of filding additives to middle distillates with improved efficiency as cold flow improvers.

OBJECT AND SUMMARY OF THE INVENTION

It has been found accordingly that crude oil middle distillates containing small amounts of A: known flow improvers, and B: copolymers consisting to at least 70% by weight of one or a plurality of monomers of both the Formula I as well as II

Rl ' H2C=C-COOR2 and H2C=CH-o-R3 (I) (II) r.~here Rl is hydrogen or m~thyl, R2 is a C8 to C18 alkyl, and R3 is a C18 to C28 alkyl, fulfill these re~uirements.
The quantitative proportion of monomers according to Formula I to monomers according to Formula II lies between 10:90 and 95O5, preferably between 40:60 and 95:5, ancl particularly preferred between 60:40 and 90:10, and the ratio of -the flow improver A to the copolymer B lies between 40.60 and 95:5, pre~erably between 60:40 and 95:5 and particularly preferred between 70:30 and 90:10.
The alkyl radicals R2 and R3 are preferably straight-chains and linear. However, up to 20~ by weight of cyclic and/or branched portions may also be included.
Examples of monomers in accordance with ~ormula I are n-octyl(meth~acrylate, n-decyl(meth)acrylate, n-dcdecyl(meth)-acrylate, n-tetradecyl(meth)acrylate, n-hexadecyl(meth)acrylate and n-octadecyl(meth)acrylate, as well as mixtures ~hereof.
Examples for monomers in accordance with Formula II are n-octadecylvinylether, n-eicocylvinylether, n-dococylvinylether, n-tetracocylvinylether, n-hexacocylvinylether and n-octacocylvinyl-ether, as well as mixtures thereo~.
The copolymers B consist of monomers in accordance with Formula I and II to at least 70% by weight. Additionally, up to 30% by weight of other ethylenically unsaturate~.? monomers may be present, such as styrols, alkylstyrols, straight--chain or branched olefins with 2 to 16 carbon atoms, vinylesters of C1- to C5-carboxylic acids, acrylnitrile, N-alkyl substitut:ed acrylamides, N-containing, ethylenically unsaturated heterocyclenes, such as vinylpyrrolidone, vinylimidazole or vinylpyridine, monomers con~aining hydroxil or amino groups such as but~nediolmono-.

acrylate, hexandiolmonoacrylate, dimethylaminoethylacrylate,diethylaminoethylacrylate, as well as (meth)acrylic acid ester of Cl- to C6-alkanols such as methylmethacrylate, ethylacrylate, isobutylacrylate and others, as well as maleic acid, ~umaric acid and itaconic acid esters of Cl- to C28-alkanols.
Examples of the flow improvers A are the already mentioned polymers described in DE-A-21 02 469 and EP--A-84 148, and copolymers of ethylene with vinylacetate, vinylpropionate, vinylbutyrate, vinylpivalate or with esters of (meth)acrylic acid which derive from alkanols with 1 to 12 carbon a~oms. Also suitable are mixtures of several copolymers of ethylene and vinylacetate (EP-A-261 951, Additive A), copolymers of ethylene with ~-olefins (EP-A-261 957, Additive D) and the mixtures of terpolymers of ethylene, vinylacetate and diisohutane with oxidized polyethyiene wax recited in DE-A-3~ 24 1~7. Copolymers of ethylene with vinylacetate or vinylpropionate or ethylhexyl-acrylate are particularly preferred.
The copolymers show synergistic effects together with the flow improvers. Although the copolymers B by themselves show no or only little improvement of the flow, the combination of A and B
far exceeds the individual effects.
The monomers in accordance with Formula I are easily accessible. They can be obtained by means of the known methods of esterification. For example, a solution of (meth)acrylic acid and an alkanol or a mixture of different alkanols is heated to boiling in an organic solvent with the addition of ths usual polymerization inhibitors, for example hydroquirone derivatives and esterification catalysts, such as sulfuric acid, p~toluene sulfonic acid or acid ion exchangers, and the r6action water which forms is removed by azeotropic distillation. Because vinylethers can cationically polymerize under acid condition- or decompose in the presence of water while forming acetaldehyde, which upsets the .

2 ~

polymerization of the radicals, neutralization oE the catalyzer acid as well as surplus (meth)acrylic acid with, ~or example, amines, or their removal by washing of the estet solution w1th alXaline means and water for producing the copolymers B is indicated. Particularly pure esters can be obtained by distillation of the pre-cleaned ester solution.
Further possibilities for producing the monomers in accordance with Formula I are the reaction of (meth3acrylic acid chloride or anhydride with the corresponding alhanols as well as the reaction, known as interesterification of low (meth)acrylic acid esters with the corresponding C8- to C18 alkanols, with the addition of acidic or basic catalysts and removal by distillation of the low alkanol. In this production method the ester should also be processed sufficiently so that no more acid is present.
The vinylethers in accordance with Formula II can be obtained in accordance with known methods by the reaction of alkanols with acetaldehyde and subsequent splitt.ing off of water or by means of the catalytic addition of acetylene to alkanols.
Particularly clean monomers can here also be obtained by distillation~ Undecomposed distillation is technically di~ficult to perform with vinylethers with more than 20 to 22 carbon atoms.
In these cases purification by filtration, extraction or recrystallization to remove the catalysts is to ~e recommended.
The production o~ the copolymers B takes place in accordance with known discontinuous or continuo~s polymerization methods, such as mass, suspension, precipitation or solution polymerization, and initiation with the usual radical donors, such as acetylcyclohexanesulfonylperoxide, diacetylperoxidicarbonate, dicyclohexylperoxidicarbonate, di-2-ethylhexylperoxidicarbonate, tert.-butylperneodecanoate, 2,2'-azobis(4-methoxy-2, ~-dimethyl-valeronitrile), tert.-butylperpivalate, tert.-butylper-2-ethyl-hexanoate, tert.-butylpermaleinate, 2,2'-azobis(isobutyronitril), bis-(tert~-butylperoxide)cyclohexane~ tert.-bukylperoxiisopropyl-carbonate, tert.-butylperacetate, di-cumylperoxide, di-tert.-amylperoxide, p-menthanehydroperoxide, cumolhydroperoxide or tert.-butylhydroperoxide and mixtures among these. Generally these initiators are used in amounts of 0.1 to 20% by weighk, preferably 0.2 to 15% by weight, in respect to the monomers.
Polymerization as a rule takes place at temperatures of 40 to 400C, preferably 70 to 300C, where it is practical to operate under pressure when solvents with boiling temperatures below the polymerization temperature are used. It is practical to perform the polymerization with air excluded, i.e. if processing is not done under boiling conditions, for example in nitrogen or carbon dioxide, because oxygen delays polymerization.
The reaction can be accelerated by the simultaneous use of redox initiators, such as benzoin, dimethylaniline, ascorbic acid as well as organically soluble complexes of heavy metals such as copper, cobalt, manganese, iron, nickel and chromium. The amounts normally used lie around 0.1 to 2000 ppm by weight, preferably 0.1 to lO00 ppm by weight. When selecting the initiator or the initiator system, it is practical in connection with the chosen polymerization temperature to see to it that the half-time of the initiator or initi~tor system is less than four hours.
It is often practical for obtaining low-molecular copolymers to operate in the presence of regulators. Suitable regulators are, ~or example, allylalcohols such as l-butene-3-ol, organic mercaptan compounds such as 2-mercaptoethanol, 2-mercapto-propanol, mercaptoacetic acid, mercaptopropionic acid, tert.-butylmercaptan, n-butylmercaptan, n-octylmercaptan, n-dodecyl-mercaptan and tert.-dodecylmercaptan, which generally are used in amounts of 0.1 to 10% by weight.
Apparatus suitable for polymerization consists o~, for example, customary mixing vessels with, for example, anchor 2 ~ 8 blade, impeller or multistage-pulse countercurrent agitators, and for continuous production mixing vessel cascades, tube reactors and static mixers.
Mass polymerization is the simplest polymerization method.
In accordance with it the monomers are polymerized in the presence of an initiator and the absence of solvents. In a practical manner all monomers are mixed in the desired composition and a small amount, for example approximately 5 to 10%, is first placed into the reactor, heated to the desired polymer;zation temperature while stirring and the remaining monomer mixture and the initiator and, if required, the coinitiator as well as the regulator are evenly admixed during 1 to 10 hours, preferably ~ to 5 hours. In this connection it is practicable to admix the initiator as well as the coinitiator separately in the form of solutions in a small amount of a suitable solvent. Then the copolyme~ can be added directly to the flow improver as a solidified molten mass or after having been placed in a suitable solvent.
A continuous high-pressure method is also suitable for producing the desired copolymers, which permits space-time yields of 1 to 50 kg polymer per liter of reactor and nour. For example, a pressure vessel, a pressure vessel cascade, a ~ressure pipe or a pressure vessel with a reaction pipe downstream, which is provided with a static mixer, can be used as polymerization apparatus.
Polymerization is preferably performed with moncmers of (meth)acrylic acid esters and vinylethers in at least two successive polymerization zones. One polymerization zone can consist of a pressure-proof vessel, the other of a heatable static mixer. Conversions of more than 99% are obtained in this case.
For example, a copolymer of (meth)acrylic acid esters and vinylethers can be produced by continuously supplying the monomers and a suitable initiator to a reactor ot two successive reaction zones, for example a reactor cascade, and continuously taking the ~ ~$ ~ 8 reaction product ~rom the reaction zone after a loitering time of 2 to 60, preferably 5 to 30 minutes, at ~emperatures between 200 and 400C. Pol~merization is practically performed at pressures of more than 1 bar, preferably between 1 and 200 bar. The copolymers obtained show solid contents of more than 99% and can be supplied to ~he middle distillate without further treatment.
Another simple me~hod for producing the aopolymers B is solution polymerization. It is performed in solvents in which the monomers and the formed copolymers are soluble. For this all those solvents are suitable which ~ulfill this condition and which do not react with the monomers. They are, for example, toluene, xylene, ethylbenzene, cumene, high-boiling aromatic mixtures such as SolvessoR 100, 150 and 200, aliphatic and cycloaliphatic hydrocarbons such as n-hexane, cyclohexane, methylcyclohexane, n-octane, iso-octane, paraffin oil~, ShellsolR TD, T and K as well as tetrahydrofuran and dioxane, where tetrahydrofuran and dioxane are particularly well suited for obtaining low-molecular copolymers. When performing the solution polymerization it is practical to place the solvent and a part of the monomer mixture (for example approximately 5 to 20%) first and to admix the remainder of the monomer mixture with the initia~or and, if required, the coinitiator, re~ulator and solvent It is also possible to admix the monomers individually at different speeds.
This is recommended in case o~ monomers with greatly differing reactivity, such as is the case with (meth)acrylates and vinylethers, and when a particularly even distribution of the less reactive vinylether is desired. In this case the less reactive monomer is admixed faster and the more reactive monomer slower.
It is also possible to place the entire amount o~ a monomer, preferably the less reactive vinylether, first and to admix only the (meth)acrylate. Finally, i~ is also possib]e to place all the monomers and the solvent first and to admix only the initiator 2 ~ 1 8 and, if required, the coinitiator and regulator (batch processing). When using this type of processing on a larger scale, however, problems in regard to heat removal may occur, so that this type of processing should only be used with low concentrations of the monomers to be polymerized. The concentration of the monomers to be polymerized lies between 20 and 80% by weight, preferably 30 and 70% by weight. The solid copolymers can be obtained without problems by evaporation of the solvent. Howaver, it is practical to select a solvent for polymerization which is compatible with the middle distillate, so that the polymerisate solution can be directly added to the middle distillate. Solution polymerization is the preferred type of producing copolymers from (meth)acrylates and vinylethers.
There is the requirement in technology to provide the additives in accordance with the invention, consisting of a flow improver A and a copolymer B, in a form which is easy to handle.
For this purpose the polymers A and B should be available in the form of one concentrate, since the use of two concentrates - one each for polymer A and polymer B - makes handling more difficult.
Because of possible incompatibility of the polymers A and B, phase separation may occur if the two polymers are purely admixed in a common solvent. If necessary this can be suppressed by means of suitable solvents and/or additives. For example, alkanols, such as iso-butanol, n-hexanol, 2-ethylhexanol, iso-decanol and their adducts with ethylene oxide, propylene oxide and/or butylene oxide, alkylphenol and their adducts with ethylene oxide, propylene oxide and/or butylene oxide, as well as semi-esters or di-esters of dicarboxylic acids with alkanols or (oligo)alkylene-oxide semi-esters such as mono or dibutylphthal~te, mono- or di-2-ethyl-hexylphthalate or di-(2-methoxyethyl)-phthalate are suitable.

2 ~ 8 Another method o~ preventing possible phase separa~ion consists in gra~ting the copolymer B at least in part on the flow improver. Mass or solution polymerization is pre~erably used ~or grafting. Polymerization can be performed in accordance with batch or feed processing. With batch processing, the entire amount of flow improver A on which the graft is to be made is placed first, together with the monomers, and the initiator and, if required, the coinitiator and regulator are admixed later.
With feed processing, the entire amount o~ flow lmprover A on which the graft is to be made is placed first, if desired together with a portion of the monomers, and the rest of the monomers, initiator and, if re~uired, the coinitiator and ~egulator are admixed later.
As already mentioned, it is not necessary to graft the copolymer B on the entire portion of the flow improver A. For example, at the ratio A:B of 90:10, the copolymer B is grafted on only a portion of 2 to 20% by weight of the entire amount of A for reasons of the space-time yield. However, at a ratio of A:B of 40:60 on a portion o~ 30 to 100% by weight of the total amount of A.
It is also unnecessary to graft the entire amount of polymer B on a portion of the flow improver A. This is ~ifficult anyway, because in general the graft yield does not reach 100%, so that it is possible that, besides graft copolymerisates and unreacted or admixed flow improver A, there is also non-grafted copolymer B in the concentrates described.
The K values (according to ~. Fikentscher, Cellulose Chemistry, Vol. 13, pp. 58 to 64 and 71 to 74 (1~32)), determined in a 2% (vol. by weight) xylolic solution of the copolymerisates B, lies between 10 and 50, preferably between lC and 40 and particularly preferred between 13 and 30. The particularly preferred range corresponds to molecular weights between 2 ~ 8 approximately 5000 and 25000 g/mol (numerical mean values determined by gel permeation chromatography ayainst polystyrol standards).
The additives A and B in accordance with the invention are added to crude oil middle distillates in amounts of 50 to 5000 ppm, preferably 100 to 2000 ppm.
The middle distillates in accordance with the invention and containing small amounts of a flow improver A and a copolymer B
may, depending on their inténded use, contain other additives or added materials such as dispersants, anti-foaming additives, corrosion protection agents, anti-oxidants, dyes, and the like.
The invention will be explained by means of the following examples.

DETAILED DESCRIPTION

Production of Copolymers B in Accordance with the Invention Example 1 In a reactor provided with an agitator, heater and feed device, 144 g laurylacrylate, 16 g n-octadecylvinylether, 0.16 g 2-mercaptoethanol, 65 g triethylamine and 69 g toluene were heated in a weak nitrogen flow to 100C while being agitated and a solution of 0.64 g tert.-butylper-2-ethylhexanoa~e in 38.2 g toluene was evenly admixed in the course of 4 hollrs. Subsequently heating was continued at 100C and the mixture thinned with approximately 54 g toluene. A clear, yellowish solution of approximately 50~ by weight was obtained. The ~ value o~ the polymer was 24.8.

2 ~

Example 2 In a reactor in accordance with Example 1, 1~4 g lauryl-acrylate, 16 g n-octadecylvinylether and ~j8.6 g ~olvessoR 150 ~a high-boiling aromatic mixture of the ESS0 compar.y) were heated in a weak nitrogen flow to 80C while being agitated and a solution of 0.48 g azoisobutyronitrile in 30 g SolvessoR 150 was evenly admixed during a period of 4 hours. Subsequently a solution of 0.16 g azoisobutyronitrile in 8.5 g SolvessoR 150 was added, heating continued at 80C for two hours and the mixture thinned with 53.5 g SolvessoR 150. A clear, colorless, viscous polymer solution of approximately 50% by weight was obtai~ed. The K value of the polymer was 28.3.

Example 3 In a reactor in accordance with Example 1, 29.2 g lauryl-acrylate, 7.3 g n-octadecylvinylether and 55.4 g ShellsolR K (a high-boiling mixture of n- and iso-paraffin of the ESSO company) were heated in a weak nitrogen flow to 100C while being agitated and, in the course of two hours, a solution of 102.1 g lauryl-acrylate, 26.0 g n-vinyloctadecyl-ether and 14.6 g ShellsolR K
and, in the course of four hours, a solution of ~.5 g tert.-butylper-2-ethylhexanoate in 25 g ShellsolR K were admixed evenly.
Subsequently a solution of 0.17 g tert.-butylper-2-ethylhexanoate in 4.2 g ShellsolR X were added, heating continued at 100C for an hour and the mixture was thinned with 67.5 g ShellsolR XO A
clear, colorless, slightly viscous polymer solution was obtained.
The K value of the polymer was 19.6.
Examples 4 to 18 were produced in a manner analog to that of Example 3.

Table Ex- Prefeed Feed 1Feed 2 Acrylate T K value ample (g) (g) (g) to vinyl- (C) No. ether 4 43.2 LA116.8 LA 0.6 TBPO 80/20100 21.8 10.8 v18 29.2 v18 30.0 SK
60.0 SK16.0 SK

54.0 LA106.0 LA 0.6 TBPO 80/2090 30.0 40.0 v18 12.0 SK 30.0 SK
69.0 SK

6 98.9 LA390.6 hA 2.2 TBPO 67/33100 17.2 49.5 v18 195.3 v18 173.3 SK
149.0 SK65.8 SK

7 83.3 LA334.7 LA 2.2 TBPO 56/44100 16.4 65.2 v18 261.8 v18 179.0 SK
149.0 SK65.8 SK

8 59.4 LA238.6 LA 2.2 TBPO 40/6095 15.8 89.0 v18 357.9 v18 179.0 SK
149.0 SR65.8 SK

9 153.6 LA358.4 LA 2.0 TBPO 80/20100 24.5 38.4 v1822 89.6 v1822 96.0 SK
193.8 SR49.3 SK

as in Example 9, but with v20+80/20 100 19.8 instead of v1822 2a~ s 11 as in Example 9, but with A8-18 80/20 ~00 22.1 instead of LA

12 7.9 LA 82.1 LA 0.3 TP0 100 23.2 20.0 v18 8.9 vpr 16.0 toluene 1.1 vpr 8.9 toluene 18.0 toluene 13 as in Example 12, but with diethylamino- 100 25.2 ethylacrylate instead of vpr 14 as in Example 12, but with styrol 100 37.4 instead of vpr as in Example 12, but with isobutylacrylat.e 100 25.2 instead of vpr 16 as in Example 12, but with vinylpyrrolidone 100 23.6 instead of vpr 17 120.0 LA 480.4 LA 1.8 TBP0 100 24.5 Com- 143.0 SK 247.6 SK 100.0 SK
parison test 18 151.4 LA 408.6 LA 2.1 AIBN 80/20 85 23.7 Com- 37.8 v4 101.2 v4 105.0 toluene paris- 209.8 C-hex 56.2 C-hex on test acc. to EP-A-360 419 ` % ~

LA Laurylacrylate = n-alkylacrylate mixture, prepared from a commercially available fatty alcohol mixture consisting of max. 1.5% by weight of n-decanol, 51 ko 57% by weight of n-dodecanol, 41 to 47% by weight o~ n-tetradecanol and max.
1.5% by weight of n-hexadecanol A8-18 n-alkylacrylate mixture, prepared from a commercially available fatty alcohol mixture consisting of 5 to 8% by weight of n-octanol, 5 to 7% by weight of n-decanol, 44 to 50% by weight of n-dodecanol, 14 to 20% ky weight of tetradecanol, 8 to 10% by weight of n-hexadecanol and 8 to 12% by weight of n-octadecanol v18 n-octadecylvinylether v1822 n-alkylvinylether mixture, prepared from a commercially available fatty alcohol mixture consisting of 41 to 43% by weight of n-octadecanol, 9 to 13% by weiyht of n-eicosanol and 43 to 46% by weight of n-docosanol v20+ n-alkylvinylether mixture, prepared from a commercially available fatty alcohol mixture consistin~ of max. 6% by weight of n-octadecanol, 40 to 60% by wei~ht of n-eicosanol, 23 to 35% by weight of n-docosanol, 10 to 18% by weight of tetracosanol and 2 to 8% by weight of n-hexacosanol vpr Vinylpropionate SK ShellsolR K

` 2 ~

v i-4 Isopropylvinylether C-hex Cyclohexane TBPO tert.-butylper-2-ethylhexanoate AIBN Azoisobutyronitrile Example 19 (Comparison kest analog to EP-A-360 419, Example C4) In a reactor in accordance with Example 1, 51.4 g (aprx. 0.1 mol) of di-n-tetradecylfumarate and 10.0 g (o.l mol) of n-butyl-vinylether were heated to 90C in a weak nitrogen flow while being agitated. Then 0.4 g AIBN were added and polymerization performed for 6 hours while further adding 0.1 g AIBN every hour. A viscous polymer solution of 99% by weight with a K value of 11.5 was obtained.

Example 20 (Comparison test analog to DE-A-16 45 785) In a reactor in accordance with Example 1, first 1.5 g borotrifluoride-etherate in 187.5 g toluene were placed and a solution of 90 g n-octadecylvinylether in 22.5 g toluene were evenly added at 30C over the period of one hour, agitation performed for another 10 minutes and polymerization stopped by the addition of 5 ml methanol. The polymer solution was precipitated in acetone and dried in a vacuum. The K value was 15.4.

Examples 17 to 20 are comparison tests an-l not a part of the present invention.

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

-2 ~ 8 Example 21 Grafting of laurylacetate and n-octadecylvinylether on a flow improver consisting of 60% by weight of ethyl~ne and ~0~ by weight of vinylpropionate with a mean molecular weight of ap~roximately 2500 (determined by means of vapor pressure osmometry) = FI(A).

In a reactor in accordance with Example 1, 215 g of the flow improver FI(A) and 86 g ShellsolR K were heated in a weak nitrogen flow to 100c while being agitated. A mixture of 516 g laurylacrylate, 12~ g n-octadecylvinylether and 73.1 g ShellsolR K
were added to this and the remainder of the mixture was evenly added over a period of two hours. Simultaneously 1.94 g tert.-butylper-2-ethylhexanoate, dissolved in 64.5 g ShellsolR K, were evenly added over a period of four hours. Subsequently a solution of 0.65 g of tert.-butylper-2-hexanoate in 21.5 g ShellsolR K were added, heating continued for an hour and the mixture was thinned with 615 g SolvessoR 150 (high-boiling aromatic mixture of the ESSO company). A slightly cloudy polymer solution of S0% by weight with a K value of 25.2 was obtained. 80 g of this were mixed with 110 g FI(A) and 110 g SolvessoR 150 at 60C. A mixture which was cloudy at room temperature was obtained, which consists of a total of approximately 80 parts of flow improver FI(A) and 20 parts of copolymer B. The mixture is stable at ~-oom temperature for more than 10 weeks.

2 ~ 8 Application Examples The following meanings apply ko what follows:

FI Flow improver, in particular FI(A) Ethylene/vinylpropionate (with aprx. 40~ by weight of vinylpropionate) of a mean molecular weight of approximately 2500 (determined by vapor pressure osmometry) FI(B) Ethylene/vinylpropionate (with aprx. 30% by weight of vinylpropionate) of a mean molecular weight of approximately 2500 FI(C) Ethylene/vinylacetate (with aprx. 30% by weight of vinylpropionate) of a mean molecular weight of approximately 2500 The ~low improvers FI(A), FI(B) and FI(C) are commercially available products, for example the KerofluxR brands of BASF.

Heating oil and Diesel fuel of a quality commercially available in West Germany were used as middle distillates. They have been designated as middle distillates I, II, III and IV.

. . .

Middle Distillate . I II III IV

Cloud point (C) ~6 +4 ~4 ~5 CFPP (C) 0 -2 -1 -2 Initial boiling point (C) 155 131 169 174 20~ boiling point (C) 232 216 222 219 50% boiling point (C) 280 262 262 272 90% boiling point (C) 352 346 351 365 Final boiling point (C) 382 375 331 385 Test Method The cold filter plugging point (CFPP) in accordance with DIN 51 428 was measured. The results are combined in the Table below.

TablP

Test AdditiveDosage CFPP (C) in the Middle Distillate No. (ppm)*
I II ,]II IV

1 Without - 0 (-2) (-1) (-2) 2 FI(A) 300 (~3~ (-2) ~-2) (-2) 3 FI(A) 500 (~3) (-2) (-1) (-3) 4 FI(B) 500 (-3) - (~4) (-2) FI(C) 500 (-3) (-4) ~~5) (-2) 6 Copolymer 3 500 (+2) - - -7 FI(A) 400 (-14) - _ _ Copolymer 1 100 8 FI(A) 400 (-13) - _ _ Copolymer 2 100 g FI(A) 300 (-10) Copolymer 3 200 FI(A) 400 (-16) - _ _ Copolymer 3 lO0 11 FI(A) 450 (-14) Copolymer 3 50 12 FI(A) 475 (-14) Copolymer 3 25 13 FI(A) 160 - _ (-15) Copolymer 4 40 14 FI(A) 240 (-13)(-16) _ (-14) Copolymer 4 60 FI(A) 320 - - (-16) Copolymer 4 80 16 FI(A) 400 (-16)(-17) _ (-15) Copolymer 4 100 17 FI(A) 160 - - ~-14) Copolymer 5 40 18 FI(A) 240 (-14)(-14) ~ (-13) Copolymer 5 60 19 FI(A) 320 - _ ~ (-16) Copolymer 5 80 FI(A) 400 (-15)(-16) ~ (-16) Copolymer 5 100 21 FI(A) 400 (-14) _ _ _ Copolymer 6 100 22 FI(A) 400 (-14) - - -Copolymer 7 lO0 23 FI(A) 400 ¢-14) - - -Copolymer 8 100 2 ~ 1 8 24 FI(A) 400 (-12) Copolymer 9 100 FI(A) . 400 (-10) Copolymer 10 100 26 FI(~) 400 (-13) - - -Copolymer 11 100 27 FI(A) 400 (~13) - - -Copolymer 12 100 28 FI(A) 400 (-15 Copolymer 13 100 29 FI(A) 400. (-10) Copolymer 14 100 FI(A) 400 (-13) Copolymer 15 100 31 FI(A) 400 (-15) Copolymer 16 100 32 FI(B) 240 (-10) (-14) _ (-12) Copolymer 4 60 33 FI(B) 400 (-10) (-15) (-12) Copolymer 4 100 34 FI(B) 160 - - (-12) Copolymer 4 40 FI(B) 320 ~ ~ , (-13) Copolymer 4 80 36 FI(B) 240 (-10) (-15) ~ (-11) Copolymer 5 60 37 FI(B) 400 (-10) (-16) ~ (-12) Copolymer 5 100 38 FI(B) 160 - _ (-11) _ Copolymer 5 40 39 FI(B) 320 - - (-13) Copolymer 5 80 2 0 ~

Copolymer 21 500 (-16) _ _ _ 41 FI(C) 400 (-13) Copolymer 4 100 Comparison Tests 42 FI(A) 400 (-1) - _ _ Copolymer 17 100 43 FI(A) 400 (-1) Copolymer 18 loo 44 FI(A) 400 (-1) Copolymer 19 loo FI(A) 400 (~5) Copolymer 20 loO

* in relation to solutions of 50~ by weight of FI(A), FI(B) and FI(C) as well as of the copo~ymers in, for example, SolvessoR
150.

As shown by the above examples, the conventional flow improvers FI(A), FI(B) and FI(C) show unsatisfactory effects in the middle distillates. Adding only the copolymers of the invention even worsens the CFPP of the middle.distillates. The synergistic effect of the flow improvers and the copolymers of the invention are made clear by Examples 7 to 40.
As shown in the comparison tests, neithex the polyacrylate (Example 42) nor the polyvinylether (Example 45)~ together with the conventional flow improvers, show satisfactory lowering of the CFPP. Also, the copolymers with short-chain vinylethers (Examples 43 and 44) described in EP-A-360 419 have shown themselves to be ineffective in connection with the above oils, while the copolymerisates of the invention o~ a~kylacrylates, - . . : . . . - : .
.

` 2 ~ 8 long-chain vinylethers and, if required, an additional monomer in combination with FI(A), FI(B) or ~I(C) clearly lower the CFPP at small dosages.

Claims

1. Crude oil middle distillates with improved cold flow properties, containing small amounts of A. conventional flow improver on an ethylene base, and B. copolymers which consist to at least 70% by weight of one or a plurality of monomers of Formula I as well a II, R1 H2C=C-COOR2 and H2C=CH-O-R3 (I) (II) where R1 is hydrogen or methyl, R2 is a C8 to C18 alkyl, and R3 is a C18 to C28 alkyl and where the weight ratio of A to B is from 40 to 60 to 95 to 5.

2. Crude oil middle distillates in accordance with claim 1, characterized in that the quantitative proportion in the copolymers B of the monomers in accordance with Formula I to monomers in accordance with Formula II is from 10 to 90 to 95 to 5.

3. Crude oil middle distillates in accordance with claim 1, characterized in that the alkyl substituents in the copolymers B are straight-chain and linear.

4. Crude oil middle distillates in accordance with claim 1, characterized in that the copolymers may contain up to 30% by weight of other ethylenically unsaturated monomers.

5. Crude oil middle distillates in accordance with claim 1, characterized in that copolymers of ethylene with vinylacetate, vinylpropionate or ethylhexylacrylate are used as convention flow improvers.

6. Crude oil middle distillates in accordance with claim 1, characterized in that the copolymers are grafted from 0 to 100%
on the conventional flow improvers.

7. Crude oil middle distillates in accordance with claim 1, characterized in that the crude oil middle distillates contain the flow improvers A and the copolymers B together in shares of 50 to 5000 ppm.