JPH0473475B2 - - Google Patents

Description

[Detailed description of the invention]

Mineral oil containing paraffin wax has the characteristic that fluidity decreases as the temperature of the mineral oil decreases. This loss of fluidity is due to the wax crystallizing into platelets (ultimately forming a spongy mass with mineral oil entrapped therein). In the past, various additives have been known that act as wax crystal modifiers when mixed with waxy mineral oils. These compositions change the shape and size of the wax crystals and reduce the adhesion between the wax and the mineral oil so that the mineral oil can retain its fluidity at low temperatures. Various pour point depressants have been described in the literature;
Some of them are used commercially. For example, U.S. Pat. No. 3,048,479 discloses the use of ethylene and _C3 - _C5 as pour point depressants for fuels, particularly heating oils, diesel and jet fuels.
The use of copolymers of vinyl esters such as vinyl acetate is taught. Ethylene and higher α-
Hydrocarbon polymer pour point depressants based on olefins such as propylene are also known. No. 3,961,916 teaches the use of copolymer mixtures in which one copolymer is a wax crystal nucleating agent and the other copolymer is a growth inhibitor to control wax crystal size. GB 1263152 suggests that wax crystal size could be controlled by the use of copolymers with lower degrees of side chain branching. A copolymer of di-n-alkyl fumarate and vinyl acetate, previously used as a pour point depressant for lubricating oils, can be used as a co-additive with an ethylene/vinyl acetate copolymer to achieve a high final boiling point for improved low-temperature flow properties. It has been proposed, for example, in British Patent No. 1469016 that it can be used to treat distillate fuels having a According to GB 1469016, these polymers can be _C6 - _C18 alkyl esters of unsaturated _C4 - _C8 dicarboxylic acids, especially lauryl fumarate and lauryl-hexadecyl fumarate. The substances used are
Polymers typically made from () vinyl acetate and mixed alcohol fumarate esters having an average of 12.5 carbon atoms (Polymer A of GB 1469016), () vinyl acetate and an average of
Polymer made from mixed alcohol fumarate esters with 13.5 carbon atoms (UK patent no.
1469016 Polymer E) and ()C ₁₂
Di-n-alkyl fumarate and _C16 methacrylate or _C16 di-n-alkyl fumarate and _C12
copolymers of methacrylates, all of which were not effective as additives for distillate fuels. The table in GB 1542295 shows that Polymer B, which is n-tetradecyl acrylate, and Polymer C, which is a copolymer of hexadecyl acrylate and methyl methacrylate, are by themselves the type of narrow boiling range fuel to which that patent relates. indicates that it is not effective as an additive in PCT Patent Application Publication No. WO83/03615 describes the mixing of copolymers of certain olefins and maleic anhydride esterified with certain alcohols with low molecular weight polyethylene in a waxy fuel believed to have a relatively low final boiling point. and show that the copolymer itself is an ineffective additive. With the increasing diversity of distillate fuels and the need to maximize the yield of this petroleum fraction, ethylene-
Fuels have emerged that cannot be treated satisfactorily with conventional additives such as vinyl acetate copolymers. One way to increase the yield of distillate fuel is to use more heavy gas oil fraction (HGO) in combination with the effluent cut or to increase the final boiling point (FBP) of the fuel above 370°C, for example. It's about cutting deeply. It is this type of fuel that the present invention is concerned with, especially fuels with a 90% boiling point above 350°C and a final boiling point above 370°C. Copolymers of ethylene and vinyl acetate, which have been widely used to improve the flow properties of previously widely available distillate fuels, have been found to be ineffective in treating the above-mentioned fuels. Additionally, British Patent No. 1469016
It has been found that the use of the mixtures exemplified in that patent is not effective as additives in the present invention. It is also sometimes necessary to lower the cloud point of distillate fuels. The cloud point is the temperature at which wax begins to crystallize from these high final boiling point fuels when they are cooled. This temperature is generally measured using a differential thermal analyzer. U.S. Patent No. 3,252,771 discloses that linear C ₁₆ to _{C 18}
A polymer of C ₁₆ to C ₁₈ α-olefins made by polymerizing an olefin mixture consisting mainly of α-olefins with an aluminum trichloride/alkyl catalyst is an easily processable low For use as pour point depressants and cloud point depressants in final boiling point distillate fuels. For fuels that boil in the range of 120℃ to 500℃ and have a final boiling point (FBP) of 370℃ or higher, which is conventionally difficult to process, the size of the wax crystals formed is controlled and the cold filter plunging point test ( Cold filter blockage point test =
Very specific copolymers are used to create filterability in both CFPPT (related to diesel vehicle drivability) and programmed cooling tests (PCT, related to heating oil operation at low temperatures). The present inventor has found that this is effective. The inventors have also found that this copolymer is effective in lowering the cloud point of many of the full range of distillate fuels. More particularly, it contains at least 25% by weight of n-alkyl groups having an average of 14 to 18 carbon atoms; The inventors have found that polymers or copolymers containing more than 18 carbon atoms in amounts of no more than 10% by weight of carbon atoms are very effective additives. Copolymers of di-n-alkyl fumarate and vinyl acetate are preferred copolymers, and the inventors have found the use of fumarates made from a single alcohol or a binary mixture of alcohols to be particularly effective. If a mixture of alcohols is used,
It is preferred to mix the alcohols before the esterification step rather than using mixed fumarates obtained individually from each single alcohol. Generally, long n-
The average number of carbon atoms in the alkyl group is the final boiling point of 370
The inventor has found that for many of the fuels found in Europe, which are in the ~410°C range, it must be between 14 and 17°C. Such fuels generally have cloud points in the range of -5°C to +10°C. If the final boiling point is increased or the heavy gas oil content of the fuel is increased, such as in fuels found in warm climates such as Africa, India, Southeast Asia, etc., the average number of carbon atoms in the alkyl group is between 16 and 18. It can be increased anywhere in between. This latter fuel can have a final boiling point of over 400°C and a cloud point of over 10°C. Preferred polymers or copolymers used as additives in the present invention are at least 10% (w/
w) mono- or di-n-alkyl esters of monoethylenically unsaturated _C4 - _C8 mono- or dicarboxylic acids (or anhydrides), where the average number of carbon atoms in the n-alkyl group is from 14 to It is 18. The mono- or di-n-alkyl esters include alkyl groups of less than 14 carbon atoms in an amount of no more than 10% (w/w) of the total alkyl groups and no more than 10% (w/w) of the total alkyl groups. containing alkyl groups of more than 18 carbon atoms. These unsaturated esters are preferably copolymerized with at least 10% (w/w) of ethylenically unsaturated esters, such as those mentioned in the co-additives section of this specification, such as vinyl acetate. Such polymers have a molecular weight range of 1000 to 100000, preferably 1000 to
It has a number average molecular weight in the range of 30,000. Mono/dicarboxylic acid esters useful in the production of polymers have the formula (Here, R ₁ and R ₂ are hydrogen atoms or C ₁ to C ₄ alkyl groups, such as methyl groups, and R ₃ is C ₁₄ to
CO.O of C ₁₈ (average) or O.CO of C ₁₄ to C ₁₈ (average)
(where the chain is an n-alkyl group) and R ₄
is a hydrogen atom, R ₂ or R ₃ ). The dicarboxylic acid mono- or diester monomers can be copolymerized with various amounts of other unsaturated monomers, such as esters, for example from 0 to 70 mole percent. Other such esters include the formula (where R ₅ is a hydrogen atom or a C ₁ -C ₄ alkyl group, R ₆ is OOR ₈ or OOCR ₈ (R ₈ is a linear or branched C ₁ -C ₅ alkyl group), R ₇
is R ₆ or a hydrogen atom). Examples of these short chain esters are methacrylates, acrylates, fumarates (and maleates) and vinyl esters. More specific examples include methyl methacrylate, isopropenyl acrylate and isobutyl acrylate. Vinyl esters such as vinyl acetate and vinyl propionate are preferred. Preferred polymers are 40-60% (mol/mol)
_C14 - _C18 (average) dialkyl fumarate and
Contains 60-40% (mol/mol) vinyl acetate. Ester polymers are generally reacted under an atmosphere of an inert gas such as nitrogen or carbon dioxide to remove oxygen, usually using a peroxide or azo type catalyst such as benzoyl peroxide or azodiisobutyronitrile. It is commonly prepared by polymerizing ester monomers in solution in a hydrocarbon solvent such as heptane, benzene, cyclohexane, or white oil at temperatures generally in the range of 20°C to 150°C. can. The polymer can be made in an autoclave under pressure or under reflux. The additives of the present invention are particularly effective when used in combination with other additives commonly known for improving the cold flow properties of distillate fuels, but are particularly effective in the types of fuels to which the present invention relates. It turned out to be true. Co-additives The additives of the present invention can be used with ethylenically unsaturated ester copolymer flow modifiers. Unsaturated monomers copolymerizable with ethylene include unsaturated mono- and diesters represented by the following general formula. formula In the formula, R ₁₀ is a hydrogen atom or a methyl group; R ₉
is a group represented by -OOCR ₁₂ (where R ₁₂ is a hydrogen atom or a group having 1 to 28 carbon atoms, more generally 1 to 28 carbon atoms)
17, preferably a straight chain or branched alkyl group having 1 to 8 carbon atoms; or R ₉ is -
A group represented by COOR ₁₂ (where R ₁₂ is not a hydrogen atom having the same meaning as above); R ₁₁ is a hydrogen atom or -COOR ₁₂ as above. _R10
and R ₁₁ is a hydrogen atom and R ₉ is -OOCR ₁₂ monomers include monocarboxylic acids having 1 to 29 carbon atoms, more generally 1 to 18 carbon atoms, preferably 2 to 5 carbon atoms. vinyl alcohol esters of monocarboxylic acids. Examples of vinyl esters copolymerizable with ethylene include vinyl acetate, vinyl propionate, vinyl butyrate, and vinyl isobutyrate, and among these, vinyl acetate is preferred. The copolymer preferably contains 10 to 40% by weight, more preferably 25 to 35% by weight of vinyl ester. This copolymer is
It may also be a mixture of two copolymers as described in US Pat. No. 3,961,916. These copolymers preferably have a number average molecular weight of 1000 to 6000, more preferably 1000 to -4000, as measured by gas phase osmotic pressure method. The additives of the present invention may be used in combination with ionic or nonionic polar compounds that can act as wax crystal growth inhibitors. Polar nitrogen-containing compounds have been found to be particularly effective. These are generally _C30 to _C300 , preferably _C50 , formed by the reaction of at least 1 mole of a hydrocarbon-substituted amine with 1 mole of a hydrocarbon acid or anhydride thereof having 1 to 4 carboxylic acid groups. ~ _C150 amine salts and/or amides. Esters/amides may also be used. These nitrogen compounds are described in US Pat. No. 4,211,534. As amines, long chain primary, secondary,
Preference is given to tertiary or quaternary amines or mixtures thereof. However, shorter chain amines can also be used, provided that the resulting nitrogen compound is oil-soluble and therefore typically contains a total of about 30 to 300 carbon atoms. Nitrogen compounds also have a carbon number of 8 to
Must have at least one straight chain alkyl segment of 40. Suitable amines include tetradecylamine,
Examples include cocoa amine and hydrogenated tallow amine. Further, examples of the secondary amine include dioctadecylamine and methyl-behenylamine. Mixtures of amines are also suitable, as are many amine mixtures derived from natural substances.
Hydrogenated beef tallow secondary amines of the formula HNR ₁ R ₂ are preferred. In this formula, R ₁ and R ₂ are approximately C ₁₄ =4
%, C ₁₆ = 31%, C ₁₈ = 59%. Examples of carboxylic acids and anhydrides thereof suitable for producing the above nitrogen compound include cyclohexanedicarboxylic acid, cyclohexenedicarboxylic acid, and cyclopentanedicarboxylic acid. Generally, these acids have a cyclic portion of about 5 to 13 carbon atoms. Preferred acids in the present invention are benzene dicarboxylic acids such as phthalic acid, and their anhydrides are particularly preferred. It is preferred that the nitrogen-containing compound has at least one ammonium salt, amine salt or amide group. A particularly preferred amine compound is an amide-amine salt obtained by reacting 1 mole of phthalic anhydride with 2 moles of dihydrogenated beef tallow amine. Other preferred compounds are diamides obtained by dehydrating the above amide-amine salts. The long-chain ester copolymers used as additives according to the invention can be used with one or both of the types of co-additives mentioned above, and with either 20/1 to 1/20 (w/w) or more. Preferably 10/1 to 1/10 (w/w), most preferably 4/1
They may be mixed at a ratio of 1 to 1/4 (w/w). The ratio of long chain ester to co-additive 1 to co-additive 2 is x/
Ternary mixtures may also be used, where x, y, and z are in the range 1-20, more preferably in the range 1-10, most preferably in the range 1-4, where y/z. The additive system of the present invention is preferably supplied as a concentrate for addition to the main distillate fuel. These concentrates can also contain other additives if necessary. These concentrates preferably contain 3
It contains ~80% by weight of additives, more preferably 5-70%, most preferably 10-60% by weight, and is preferably a solution in oil. Such concentrates are also within the scope of this invention. Additives are generally added to fuels.
Amounts of additives from 0.0001 to 5% by weight, more preferably from 0.001 to 2% by weight are used. The invention is illustrated by the following examples, in which the effectiveness of the additives of the invention as pour point depressants and filterability improvers was compared to other additives by the following tests. Testing One method is to test the response of mineral oils to additives using a cold filter plugging point test.
CFPPT). This method is described in the Journal of the Institute of Petroleum.
Petroleum), Volume 521, No. 510, June 1966 issue,
This is done by the operations detailed on pages 173-185. This test is intended to relate to the cold flow properties of middle distillates in diesel vehicles. Briefly, a 40 ml sample of mineral oil is placed in a bath maintained at about -34°C, and non-linear cooling is performed at a rate of about 1°C/min. Periodically (starting at a temperature of at least 2° C. above the cloud point and every 1° C. decrease), the cooled mineral oil was tested for flowability through a fine screen within a given period of time.
This test was performed with a test apparatus connected to the lower end of an inverted funnel pipette that was placed below the surface of the mineral oil sample. A 350 mesh screen with an area defined by a diameter of 12 mm is spread over the mouth of the funnel. This periodic test is initiated by applying a vacuum to the top of the pipette and the mineral oil rises through the screen into the pipette to the 20 ml volume mark. After a successful ascent, immediately return the mineral oil to the CFPP tube. This test is performed for each 1° C. temperature decrease until no mineral oil can be filled into the pipette within 60 seconds. Then, this temperature is defined as the CFPP temperature.
Then, we calculated the difference between the CFPP of mineral oil without additives and the CFPP of the same mineral oil with additives.
CFPP descent. A more effective flow improver will result in a greater CFPP drop with the same concentration of additive. Another way to examine the flowability improvement effect is under the conditions of a programmed cooling test (PCT test) for the handling of flowability-improved distillates. This test is a slow cooling test and is intended to correlate with pumping of stored heating oil. The cold flow properties of fuels containing additives were determined by the PCT test described below. 300 ml of fuel was cooled linearly at a rate of 1° C./hour to the test temperature and maintained at this temperature. After being maintained at the test temperature for 2 hours, approximately 20 ml of the surface layer was removed by suction to prevent the test from being influenced by unusually large wax crystals that tend to form at the mineral oil/air interface during cooling. do. Place the wax in the bottle, stir gently to disperse it, and then insert the CFPPT filter device. Next, open the stopper, suck in mercury at 500 mm, and pass the fuel oil through a filter into a graduated receiver.
Close the stopper when 200ml is filled. If 200ml is drawn through the specified mesh size within 10 seconds, record a pass; if the flow rate becomes too slow, indicating that the filter is clogged, record a fail. . 20, 30, 40, 60, 80, 100, 120, 150, 200,
Using a CFPPT filter device with filter screens of 250 and 350 mesh numbers, determine the finest mesh (largest mesh number) through which the fuel oil will pass. The larger the mesh number through which the wax-containing fuel oil passes, the smaller the wax crystals and the greater the fluidity-improving effect of the additive. It should be noted that the same treatment level with the same flow improving additive will not give exactly the same results for two fuel oils. The cloud point of distilled fuels is determined by the standard cloud point test (IP-219).
or ASTM-D2500), and the wax appearance temperature was estimated (without correcting for thermal lag) by measuring on a kerosene control sample using a differential thermal analyzer Mettler TA 2000B. In differential thermal analysis, a 25 microliter fuel sample is cooled at a cooling rate of 2°C/min from a temperature at least 10°C above the predicted cloud point, and the cloud point of the fuel is determined by the differential thermal analyzer. Estimated as wax appearance temperature +6°C. Examples Fuel oil The fuel oil used in the examples is as follows.

[Table] Temperature °C

【table】

[Table] Additives used Ester copolymer of the invention The following linear di-n-alkyl fumarates were copolymerized with vinyl acetate (in a 1/1 molar ratio). Polymer n-alkyl chain length A1 10 A2 12 A3 14 A4 16 A5 18 A6 20 By mixing two alcohols with the following chain lengths with fumaric acid before esterification, the following (1/1 (w/w) )) made a binary ester. Copolymerization was then carried out using vinyl acetate (in a 1/1 molar ratio). Polymer n-alkyl chain length B1 10/12 B2 12/14 B3 14/16 B4 16/18 B5 18/20 Fumarate-vinyl acetate copolymers from fumarate esters esterified with alcohol mixtures containing a range of chain lengths I made it. The alcohol was first esterified by mixing with fumaric acid and polymerized with vinyl acetate (1/1 molar ratio) to produce a product similar to that of Polymer A of GB 1469016. N-Alkyl Chain Length Polymer 8 10 12 14 16 18 C1 9 11 36 30 10 4 C2 10 7 47 17 8 10 The value is the percentage (w/w) of the alcohol containing that n-alkyl chain in the mixture. The average number of carbon atoms is 12.8 and 12.6, respectively. Fumarate-vinyl acetate copolymers were made by first making a series of fumarates. A set of fumarates were then added to 5/2 in a similar manner to Example Polymer E of GB 1469016.
(w/w) ratio before copolymerization with vinyl acetate to obtain Polymer D below.

[Table] The average number of carbon atoms of Polymer D is 13.9. Short Chain Ester Copolymer An ethylene-vinyl acetate copolymer with the following properties was used as a co-additive.

[Table] Molecular Weight Polar Nitrogen-Containing Compounds Compound F was prepared by mixing 1 molar proportion of phthalic anhydride with 2 molar proportions of di-hydrogenated beef tallow amine at 60°C. A dialkylammonium salt of 2-N,N-dialkylamidobenzoate is formed. Fuel Oil Testing Additive formulation and cold flow test results are summarized in the table below. In the table, concentrations are in parts per million (ppm) in fuel oil. CFPP reduction is the difference (in °C) between the CFPP of the untreated fuel and the lower CFPP of the treated fuel. The PCT value is the mesh number that passed at -9°C, and the higher the PCT value, the better the passage. The table below shows the effect of fumarate-vinyl acetate copolymers of specific n-alkyl chain lengths on fuels.

[Table] Therefore, the highest ability is C ₁₄ in fumarate
Observed in the case of alkyl groups. Fumarate-vinyl acetate copolymers of specific n-alkyl chain lengths were used in fuel oils with ethylene-vinyl acetate copolymers (1/4 (w/
It was found that the effect of the ratio w) is as follows.

Table The highest performance is again observed in the case of C ₁₄ alkyl groups in fumarate. The effects of combining a fumarate-vinyl acetate copolymer of a specific n-alkyl chain length with an ethylene-vinyl acetate copolymer as a co-additive (1/4 (w/w) ratio) in fuel oil are as follows: It was hot.

[Table] Therefore, the highest ability is again in fumarate.
Observed in the case of _C14 alkyl groups. In fuel oil, the effect of using fumarate-vinyl acetate copolymers made from vicinal alcohol binary mixtures with ethylene-vinyl acetate copolymers (1/4 (w/w) ratio) is:
It was as follows.

[Table] The highest ability here is C ₁₅ in fumarate
Observed in the case of alkyl groups. The effects of using fumarate-vinyl acetate copolymer together with ethylene-vinyl acetate copolymer (1/4 (w/w) ratio) in fuel oil were as follows.

TABLE The highest performance is observed in the case of C ₁₄ /C ₁₅ alkyl groups in fumarates. The effects of using fumarate-vinyl acetate copolymer together with ethylene-vinyl acetate copolymer (1/4 (w/w) ratio) in fuel oil were as follows.

[Table] The highest ability is C ₁₄ / again in fumarate
observed in the case of _C15 alkyl groups. The effects of using fumarate-vinyl acetate copolymer together with ethylene-vinyl acetate copolymer (1/1 (w/w) ratio) in fuel oil are as follows and compared to ethylene/vinyl acetate copolymer alone.

【table】

Table: The effects of a ternary additive combination consisting of a fumarate-vinyl acetate copolymer, an ethylene-vinyl acetate copolymer, and a polar nitrogen compound in fuel oil were as follows.

[Table] The effects of various binary or ternary additive combinations on fuel oils were as follows.

[Table] The effect of fumarate-vinyl acetate copolymers of specific n-alkyl chain lengths on the pour point of fuel oil was as follows.

Table: Pour point was determined by ASTM D-97 test. The effect of the additive of the present invention on the wax appearance temperature of the fuel oil used above was measured,
Comparisons were made with other additives outside the scope of the present invention.

[Table] Lucopolymer

[Table] Lucopolymer

[Table] Lucopolymer

[Table] Lucopolymer

[Table] Lucopolymer
As shown in all the examples above, the peak of cloud point lowering effect is at about 16
Found in an alkyl group of 5 carbon atoms.

Claims (1)

[Scope of Claims] 1 Contains at least 25% by weight of n-alkyl groups having an average of 14 to 18 carbon atoms;
containing less than 14 carbon atoms in an amount that is no more than 10% by weight of the alkyl group;
(a) an additive containing a polymer or copolymer containing more than 18 carbon atoms;
Distilled fuel oil boiling in the range ~500°C and having a final boiling point between 370°C and 410°C, or (b) boiling in the range 120°C to 500°C and having a final boiling point above 400°C and a cloud point higher than 10°C. Additive for improving the low-temperature properties of distilled fuel oil. 2. The additive for improving low temperature properties according to claim 1, wherein the copolymer is a copolymer of vinyl acetate and di-n-alkyl fumarate. 3. The additive for improving low-temperature properties according to claim 1 or 2, further comprising a copolymer of ethylene and a vinyl ester consisting of a carboxylic acid having 1 to 4 carbon atoms. 4. The additive for improving low temperature characteristics according to any one of claims 1 to 3, further comprising a polar nitrogen-containing compound. 5 Contains at least 25% by weight of n-alkyl groups having an average of 14 to 18 carbon atoms;
18 in an amount that is no more than 10% by weight of the alkyl group and contains less than 14 carbon atoms in an amount that is no more than 10% by weight of the alkyl group
120 to 2% by weight of polymers or copolymers containing more than
Petroleum distillate boiling in the range 500°C and having a final boiling point between 370 and 410°C or petroleum distillate boiling in the range 120 and 500°C and having a final boiling point above 400°C and a cloud point above 10°C distillate. 6. A petroleum distillate according to claim 5, wherein the copolymer is a copolymer of vinyl acetate and di-n-alkyl fumarate. 7. The petroleum distillate according to claim 5 or 6, further comprising a copolymer of ethylene and a vinyl ester of a carboxylic acid having 1 to 4 carbon atoms. 8. The petroleum distillate according to any one of claims 5 to 7, further comprising a polar nitrogen-containing compound.