Copolymer and use thereof for reducing crystallization of paraffin crystals in fuels

Abstract

The present invention relates to a copolymer obtainable by copolymerization of (A) at least one unsaturated dicarboxylic acid or derivatives thereof, (B) at least one -olefin having from at least 6 up to and including 20 carbon atoms, (C) optionally at least one C.sub.3- to C.sub.20-alkyl ester of acrylic acid or methacrylic acid or a mixture of such alkyl esters and (D) optionally one or more further copolymerizable monomers other than monomers (A), (B) and (C), with a molar incorporation ratio of (A):(B):(C):(D) of 1:0.5 to 2.0:0 to less than 0.5:0 to 0.1 followed by the reaction with at least one dialkylamine (E), where the two alkyl radicals in the at least one dialkylamine (E) are independently alkyl radicals having at least 17 up to 30 carbon atoms.

Claims

1. A fuel composition, comprising: a fuel, a copolymer having a wax anti-settling effect, and at least one further component comprising a cold flow improver, wherein the copolymer is obtained by copolymerization of monomers comprising: (A) at least one unsaturated dicarboxylic acid or derivative thereof; (B) at least one -olefin comprising from 6 to 20 carbon atoms; (C) optionally at least one C.sub.3- to C.sub.20-alkyl ester of acrylic acid or methacrylic acid or a mixture of such alkyl esters; and (D) optionally at least one further copolymerizable monomer other than monomers (A), (B) and (C), wherein a molar incorporation ratio of (A):(B):(C):(D) is from 1:0.5 to 2.0:0 to less than 0.5:0 to 0.1, followed by reaction with at least one dialkylamine (E), where the two alkyl radicals in the at least one dialkylamine (E) are independently alkyl radicals comprising from 17 to 30 carbon atoms, wherein the molar ratio of dialkylamine (E) based on units of the dicarboxylic acid (A) incorporated in the copolymer is at least 1.1:1.

2. The fuel composition according to claim 1, wherein monomer (A) is at least one selected from the group consisting of maleic acid, fumaric acid, 2-methylmaleic acid, 2,3-dimethylmaleic acid, 2-methylfumaric acid, 2,3-dimethylfumaric acid, methylenemalonic acid and tetrahydrophthalic acid and derivatives thereof.

3. The fuel composition according to claim 1, wherein monomer (B) is at least one selected from the group consisting of 1-hexene, 1-heptene, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, 1-tridecene, 1-tetradecene, 1-pentadecene, 1-hexadecene, 1-heptadecene, 1-octadecene, 1-nonadecene and -eicosene.

4. The fuel composition according to claim 1, wherein monomer (C) is at least one selected from the group consisting of esters of acrylic acid and methacrylic acid with n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol, tert-butanol, n-pentanol, tert-pentanol, n-hexanol, n-heptanol, n-octanol, 2-ethylhexanol, n-nonanol, isononanol, n-decanol, 2-propylheptanol, n-undecanol, isoundecanol, n-dodecanol, n-tridecanol, isotridecanol, 3,3,5,5,7-pentamethyloctanol, n-tetradecanol, n-pentadecanol, n-hexadecanol, n-heptadecanol, isoheptadecanol, 3,3,5 5,7,7,9-heptamethyldecanol, n-octadecanol and n-eicosanol.

5. The fuel composition according to claim 1, wherein the optional monomer (D) is at least one selected from the group consisting of cycloaliphatic (meth)acrylates (D1), (meth)acrylates of polyalkylene glycol monoalkyl ethers (D2), vinyl alkanoates (D3), allyl compounds (D4), vinyl ethers (D5), N-vinyllactams (D6), N-vinylimidazoles (D7), ethylenically unsaturated aromatics (D8), sulfur dioxide (D9), ethylenically unsaturated nitriles (D10) and esters of acrylic acid or methacrylic acid that bear at least one aromatic ring system (D11).

6. The fuel composition according to claim 1, wherein the monomers in copolymerized form have a molar incorporation ratio of (A):(B):(C):(D) of 1:0.6 to 1.5:more than 0 to less than 0.5:0 to 0.05.

7. The fuel composition according to claim 1, wherein the dialkylamine (E) is di-n-octadecylamine, di-n-nonadecylamine or di-n-eicosylamine.

8. The fuel composition according to claim 1, wherein the molar ratio of dialkylamine (E) based on incorporated units of the dicarboxylic acid (A) in the copolymer is at least 1.2:1 and up to 2.0:1.

9. The fuel composition according to claim 1, wherein the monomers in copolymerized form have a molar incorporation ratio of (A):(B):(C):(D) of 1:0.6 to 1.5:0:0 to 0.05, with the proviso that the sum total of the statistical average number of carbon atoms in the monomer (B) and the statistical average number of carbon atoms of the alkyl radicals in the dialkylamine (E) is at least 30.

10. The fuel composition according to claim 9, wherein the molar ratio of dialkylamine (E) based on incorporated units of the dicarboxylic acid (A) in the copolymer is from 1.1:1 to 1.9:1.

11. The fuel composition according to claim 1, wherein the copolymer has a weight-average molecular weight (M.sub.w) of 2000 to 20,000 as determined by gel permeation chromatography.

12. The fuel composition according to claim 1, wherein the copolymer is obtained by solvent polymerization, emulsion polymerization, precipitation polymerization or bulk polymerization at a polymerization temperature of 50 to 250 C. in at least one apparatus operated continuously or batchwise.

13. A process, comprising reducing crystallization of paraffin crystals in a fuel, the process comprising: combining the fuel and a cold flow improver with a copolymer having a wax anti-settling effect, thereby reducing crystallization of paraffin crystals in the fuel and obtaining the fuel composition according to claim 1.

14. A process for improving a cold flow property of a fuel oil and/or improving filterability of a fuel oil, the process comprising: combining the fuel, a cold flow improver, and a copolymer having a wax anti-settling effect, thereby obtaining the fuel composition according to claim 1.

15. The fuel composition according to claim 1, wherein the fuel composition has a content of 10 to 5000 ppm by weight of one or more of the copolymer; and wherein the fuel composition optionally further comprises at least one further additive selected from the group consisting of paraffin dispersants, conductivity improvers, anticorrosion additives, lubricity additives, antioxidants, metal deactivators, antifoams, demulsifiers, detergents, cetane number improvers, solvents or diluents, dyes and fragrances.

Description

EXAMPLES

Preparation Example 1 (MA/Dodecene:Distearylamine 1:1:1.4)

(1) Step 1:

(2) A stirred vessel was initially charged with 133 g of Solvesso 150 and 400 g of 1-dodecene. The initial charge was sparged with N.sub.2 and heated to 150 C. On attainment of the temperature, 233.48 g of maleic anhydride (MA, equimolar to 1-dodecene), melted at 70 to 90 C., were added continuously to the reaction mixture through a heatable feed within 6 hours.

(3) In parallel, within 6 hours, 6.46 g of di-tert-butyl peroxide as initiator were metered into the reaction. After the feeding of maleic anhydride and initiator had ended, the reaction mixture was left to stir at 150 C. for a further hour, diluted with a further 493.6 g of Solvesso 150 and cooled down to 95 C.

(4) Step 2:

(5) To the reaction mixture from step 1 were added 870 g of distearylamine within 15 min, and a further 870 g of Solvesso 150 were added. The mixture was stirred at 160 C. for 4 hours. Subsequently, another 870 g of distearylamine were added, and the reaction mixture was cooled down to 95 C. and stirred for 1 hour. Subsequently, the mixture was cooled down to room temperature.

(6) The reaction product was solid and pale yellowish; the solids content was 61%.

Preparation Example 2 (MA/Dodecene:Distearylamine 1:1:1.4)

(7) The procedure was as in preparation example 1, except that what were added to the reaction mixture from step 1 within 15 min were 1243 g of distearylamine and a further 1243 g of Solvesso 150. The mixture was stirred at 160 C. for 4 hours. Subsequently, another 497 g of distearylamine were added, and the reaction mixture was cooled down to 95 C. and stirred for 1 hour. Subsequently, the mixture was cooled down to room temperature.

Preparation Example 3 (MA/Dodecene:Distearylamine 1:1:2)

(8) The procedure was as in preparation example 1, except that what were added to the reaction mixture from step 1 within 15 min were 1243 g of distearylamine and a further 1243 g of Solvesso 150. The mixture was stirred at 160 C. for 4 hours. Subsequently, another 1243 g of distearylamine were added, and the reaction mixture was cooled down to 95 C. and stirred for 1 hour. Subsequently, the mixture was cooled down to room temperature.

Preparation Example 4 (MA/Dodecene/Lauryl Acrylate:Distearylamine 1:1:0.0106:1.4)

(9) The procedure was as in preparation example 1, except that 1% by weight of lauryl acrylate based on the total amount of copolymer for the preliminary stage was included in the initial charge together with 1-dodecene and Solvesso 150.

Preparation Example 5 (Comparison) (MA/Decene/Lauryl Acrylate:Distearylamine 1:1:1:2)

(10) The procedure was as in preparation example 3, with the following differences:

(11) Rather than 1-dodecene, the equimolar amount (based on MA) of 1-decene and additionally the equimolar amount (based on MA) of lauryl acrylate was used.

(12) Like MA, the lauryl acrylate was metered in within 6 hours. In addition, rather than 133 g, 400 g of Solvesso 150 were now added to the initial charge. At the end of step 1, only 226.6 g of Solvesso 150 were used for dilution.

Preparation Example 6 (Comparison) (MA/Dodecene:Distearylamine:Didodecylamine 1:1:0.7:0.7)

(13) The procedure was as in preparation example 1, except that, in step 2, after the first addition of 870 g of distearylamine, equimolar amounts (based on distearylamine) of didodecylamine were added.

Preparation Example 7 (Comparison) (MA/Dodecene/Lauryl Acrylate:Distearylamine 1:1:1:2)

(14) The procedure was as in preparation example 5, except that, rather than 1-decene, equimolar amounts of 1-dodecene were used.

(15) Use Examples

(16) In the use examples, diesel fuels (DF) having the details of origin and indices reported in table A were used.

(17) TABLE-US-00001 DF 1 DF 2 DF 3 Origin Central Central Central Europe Europe Europe Cloud point CP [ C.] 7 7 5 CFPP [ C.] 9 8 7 Density @15 C. [kg/m3] 839 840 833 90% by vol. 20% by vol. [ C.] 121 116 131 IBP [ C.] 172 166 170 FBP [ C.] 354 355 361 n-Paraffins [%] 20.27 19.52 19.84

(18) Efficacy as Paraffin Dispersants (WASAs)

(19) In the examples which follow (tables 1-3), the copolymers of the present invention were tested for their efficacy as paraffin dispersants (WASAs) in the presence of a customary flow improver (MDFI) and compared with noninventive copolymers.

(20) The cloud point (CP) to ISO 3015 and the CFPP to EN 116 of the additized fuel samples were determined. For this purpose, the additized fuel samples in 500 ml glass cylinders, in order to determine the delta CP, were cooled to 16 C. in a cold bath and stored at this temperature for 16 hours. For each sample, the CP was again determined to ISO 3015 on the 20% by volume base phase separated off at 16 C. The smaller the deviation of the CP of the 20% by volume base phase from the original CP (delta CP) for the respective fuel sample, the better the dispersion of the paraffins.

(21) The smaller the delta CP and the lower the CFPP, the better the cold flow characteristics of a diesel fuel.

(22) The inventive copolymers improve the cold flow characteristics in terms of delta CP or CFPP or both parameters.

(23) The procedure for the brief sediment test was analogous to Aral Method QSAA FKL 027, with the following modification:

(24) Diesel fuels 1 and 2: cool to 16 C. and keep at this temperature for 16 h

(25) Diesel fuel 3: cool to 13 C. and keep at this temperature for 16 h

(26) WASA formulations comprise 30% by weight of the particular copolymer.

(27) The MDFI used is a commercially available flow improver formulation of an ethylene/vinyl acetate copolymer.

(28) TABLE-US-00002 TABLE 1 DF 1; CFPP: 9 C.; CP: 7 C. WASA formulation MDFI comprising 30% by WASA dosage weight of copolymer dosage CFPP Delta CP [ppm] from example [ppm] [ C.] [K] 200 Example 2 150 29 1 200 Example 1 150 31 0.5 200 Example 4 150 29 1.1 200 Example 3 150 27 0.9 200 Comparative example 5 150 29 2.4 200 Comparative example 6 150 26 7.6

(29) TABLE-US-00003 TABLE 2 DF 2; CFPP: 8 C.; CP: 7 C. WASA formulation MDFI comprising 30% by WASA dosage weight of copolymer dosage CFPP Delta CP [ppm] from example [ppm] [C] [K] 200 Example 1 150 27 1.3 200 Comparative example 7 150 25 2.2

(30) TABLE-US-00004 TABLE 3 DF 3: CFPP: 7 C.; CP: 5 C. WASA formulation MDFI comprising 30% by WASA dosage weight of copolymer dosage CFPP Delta CP [ppm] from example [ppm] [ C.] [K] 100 Example 1 150 27 1.3 100 Comparative example 7 150 20 2