FR2471405A1 - Terpolymer from acrylic! ester, di:isobutylene! - and di:carboxylic acid deriv., as low temp. flow improver for hydrocarbon oils - Google Patents

Abstract

A terpolymer consists of (A) 10-94 mols.% of acrylic ester units of formula (-CH2- C(R')(COOR"))- where R' is H or CH3 and R" is 1-30C alkyl, (B) 3-65 mols.% of units derived from dicarboxylic acids and of formula (I), (II) or (III) where R"' and R"" are H or CH3; X and Y are OH, OR", OR""', NH2 or NHR""'; and R""' is a monovalent gp. derived from a cpd. with at least 1 OH and/or amine gp., and (C) 3-40 mols.% of a diisobutylene unit of formula -(CH2-C(CH3)(CH2-C(CH3)3). The mol. wt. is 500-250,000. The polymers are used in lubricants and hydrocarbon oils, e.g. gas oils, domestic fuel oils, and crude petroleum, esp. in heavy oils, to improve flow at low temp. The diisobutylene units improve the solubility in hydrocarbon oils. The dicarboxylic acid units can be reacted with (poly)amino and/or (poly)-OH cpds. to improve the dispersant effect. The terpolymers are cheaper than acrylic ester polymers.

Description

The present invention relates to improving the fluidity and low temperature flow properties of hydrocarbon oils
It relates more particularly to compositions of hydrocarbon oils such as gas oils, domestic fuel oils, heavy fuels (or No. 2 fuels), residual fuels or crude oils whose rigging point or temperature freezing is lowered by the addition of certain soluble terpolymers, which will be defined in detail in the description below.

It is well known that certain hydrocarbon oils contain compounds such as paraffins, asphaltenes or reins, which make them viscous and give them unacceptable flow properties. These oils behave at low temperatures like non-liquid
Newtonians and, in particular, they exhibit a temperature of freezing or solidification in the cold, as well as particular phenomena of hysteresis, which considerably limit their uses, for example as fuels, and their exploitation, for example in the case of crude oils .

One solution proposed to remedy these drawbacks consists in subjecting the hydrocarbon oils to dewaxing and / or dealphalting processes, but these processes are often very expensive.
Another solution used to reduce the viscosity or the freezing point of hydrocarbon oils rich in asphaltic and / or paraffinic compounds consists in diluting them by adding hydrocarbon oils or their lighter distillates. '' an expensive solution, being given the much higher cost of light oils compared to heavy oils
A third solution, which most often proves to be between the least expensive and the most effective, consists in adding small quantities of polymeric additives to thin the hydrocarbon oils or improve their flow properties at low temperature.

 Among the numerous additives proposed in the prior art, mention may be made of polymers or copolymers containing olefins or diolefins, optionally hydrogenated st / or alkylated, polymers or copolymers of unsaturated esters, such as acrylates or methacrylates, as well as certain copolymers of olefins and unsaturated esters, such as copolymers of ethylene or propylene with vinyl acetate or aorylates and methacrylates. These various additives are designed to lower the limit filterability temperature of domestic gas or fuel oils, and improving the low temperature flow properties of certain petroleum oils or crude oils rich in paraffins.

However, these various additives prove to be very ineffective in improving the fluidity and the flow properties of "heavy" hydrocarbon oils, such as high boiling point fuels, # 2 fuels, atmospheric distillate (residual fuels) or crude oils rich in asphaltenes.

 It has now been discovered that it is possible to improve the cold flow properties of such compositions of hydrocarbon oils (and in particular the fluid, in the case of heavy oils) by the addition of small amounts of certain terpolymers defined below.

The compositions of hydrocarbon oils of the invention are characterized in that they comprise a major proportion of a composition chosen from gas oils, domestic fuel oils, heavy fuels, n02 fuels, residual fuels and oils crude and a minor proportion of at least one soluble terpolymer comprising units deriving from at least one unsaturated monoester, units deriving from at least one α, dicarboxylic compound containing ethylenic unsaturation and units deriving from diisobutylene.

(dérivant respectivement d'un monoester vinylique ou d'un monoester acrylique), dans lesquelles R1 représente un atome d'hydrogène ou un radical alkyle contenant de 1 à 4 atomes de carbone et R2 représente un radical alkyle contenant de 1 à 30 atomes de carbone;;
(B) des unités, dérivant d'au moins un composé# # dicarboxylique à insaturation éthylénique, et répondant à l'une des formules générales

dans lesquelles, R et R4 , identiques ou différents, représentent un atome d'hydrogène ou un radical méthyle, X et Y, identiques ou différents, sont choisis parmi les groupements
4 - OH, -OR5, -NH1/2 et NHR5, R5 représentant un radical organique monovalent dérivé d'un composé organique renfermant au moins une fonction hydroxyle et/ou au moins une fonction amine, et
(c) des unités de formule

dérivant du diisobutyldne.Les teneurs respectives en unités (A), (B) et(C) des terpolymères utilisés dans l'invention peuvent varier dans de larges proportions.Ainsi par exemple, pour 100 unités constituant ces terpolymères, le nombre d'unités (A) peut être de 10 à 94, de préférence de 40 à 80, le nombre d'unités (B) peut btre de 3 à 50,de préférence de 10 à 35, et le nombre d'unités (C) peut être de 3 à 40, de préférence de 10 à 25. On peut aussi, sans sortir du cadre de l'invention, s'écarter quelque peu de ces valeurs. Par ailleurs, avantageusement la teneur en unités (B) dérivant d'un composé dicarboxylique à insaturation éthylénique sera au moins égale à celle des unités (C) dérivant du diisobutylène.The hydrocarbon oil compositions of the invention are more particularly characterized in that they contain from 0.005 to 2% by weight of one or more terpolymers having a number average molecular mass, determined by tonometry or osmometry of approximately 500 to 200,000, including
(A) units corresponding to one of the general formulas

(derived respectively from a vinyl monoester or an acrylic monoester), in which R1 represents a hydrogen atom or an alkyl radical containing from 1 to 4 carbon atoms and R2 represents an alkyl radical containing from 1 to 30 carbon atoms carbon;;
(B) units, derived from at least one # # dicarboxylic compound containing ethylenic unsaturation, and corresponding to one of the general formulas

in which, R and R4, identical or different, represent a hydrogen atom or a methyl radical, X and Y, identical or different, are chosen from the groups
4 - OH, -OR5, -NH1 / 2 and NHR5, R5 representing a monovalent organic radical derived from an organic compound containing at least one hydroxyl function and / or at least one amine function, and
(c) formula units

derived from diisobutyldne. The respective contents in units (A), (B) and (C) of the terpolymers used in the invention can vary within wide limits. For example, for 100 units constituting these terpolymers, the number of units (A) can be from 10 to 94, preferably from 40 to 80, the number of units (B) can be from 3 to 50, preferably from 10 to 35, and the number of units (C) can be from 3 to 40, preferably from 10 to 25. It is also possible, without departing from the scope of the invention, to deviate somewhat from these values. Furthermore, advantageously the content of units (B) deriving from an ethylenically unsaturated dicarboxylic compound will be at least equal to that of the units (C) deriving from diisobutylene.

 The number-average molecular mass of the terpolymers considered in the invention is preferably from 1000 to 700 μm.

 By way of illustration of the unsaturated monoesters from which the units (A) of the terpolymers considered in the invention are derived, mention may be made of vinyl acetate and methyl, propyl, butyl, ethylhexyl or decyl acrylates or methacrylates, hexadecyl, dodecyl, octadecyl or eicosyl. Mention may also be made of the acrylates and methacrylates of industrial alcohols containing on average 12 carbon atoms (lauryl acrylate and methacrylate) or 18 carbon atoms (stearyl acrylate and methacrylate).

By way of illustration of the unsaturated ap-dicarboxylic compounds from which the units (B) of the terpolymers considered in the invention are derived, mention may be made of anhydrides or maleic, fumaric, citraconic or mesaconic acids, the corresponding derivatives having at least an ester or amide function as well as the corresponding imides (optionally N-substituted).

 For reasons of both availability and price of raw materials on the one hand as well as reasons of solubility and performance of terpolymers in hydrocarbon oils on the other hand, the monomers will preferably be chosen to constitute the units (A) from acetate. vinyl and methyl, butyl, dBethylhexyl, stearyl or lauryl acrylates or methacrylates, and the units (B) among maleic anhydride or acid, alkyl maleates and optionally N-substituted maleimides.

The terpolymers used in the hydrocarbon oil compositions of the invention can title prepared according to conventional methods of radical polymerization, for example in the presence of an initiator of the azobisisobutyronitrile or peroxide type, in bulk or in solution in a hydrocarbon solvent , such as for example cyclohexane0 isooctane, dodecanea benzene, toluene, xylene, diisopropylbenzene, tetrahydrofuran or dioxane.

Preferably, relatively high boiling hydrocarbon fractions, such as kerogen or diesel.

 Appropriate proportions of the various monomers are used; in general, I am involved in a molar proportion of #ss -dicarboxylic compound with ethylenic unsaturation (for example maleic anhydride) at least equal to the molar proportion of diisobutylene.

 If it is desired to obtain the terpolymers in a form such that at least part of the units (B) has ester, amide or imide functions, according to a particular mode of synthesis of the terpolymers, it can be carried out, in a first step, radical terpolymerization of one or more unsaturated monoesters with a mixture of anhydride or maleic acid and dediisobutylene. The reaction mixture thus obtained is, in a second step, reacted with a mono-or polyamine compound and / or mono- or polyhydroxylated, at a temperature generally between 80 and 1600C, (optionally in the presence of a small amount of an acid soluble in the hydrocarbon phase, when the compound is essentially hydroxylated). The amidation and / or imidation and / or esterification reactions of all or part of the carboxylic groups of the terpolymer, during the second step, confer on the compositions of the invention additional properties of dispersivity, and of antiflocculating agent or preventing the sedimentation of asphaltenes, these properties often being very useful in order to improve the fluidity of heavy hydrocarbon oils. In addition, the esterification of part of the carboxylic groups of the terpolymer with long chain linear saturated alcohols, for example having up to 30 carbon atoms, can contribute to increasing the solubility of the additive in oils and its activity. as a step-down of the flow temperature.

 According to another particular mode of synthesis of the terpolymers considered in the invention, the radical terpolymerization of one or more unsaturated monoesters is carried out with a mixture of alkyl maleates and / or maleimides, optionally N-substituted, and of diisobutylene.

For the preparation of the improved hydrocarbon oil compositions of the invention, use is generally made of 0.005 to 2% by weight and preferably 0.01 to 0.5% by weight of one or more terpolymers, relative to the weight of the hydrocarbon oil.

The terpolymer can be mixed directly in powder or granule form, in the oil to be treated, but preferably it will be added in the form of a concentrated solution, for example a solution containing 20 to 60 parts by weight of terpolymer. dissolved in 80 to 40 parts by weight of xylene toluene; of kerosene or diesel.

The mixing can be carried out at ordinary temperature, but it is often preferable to carry out the hot mixing, for example by adding the terpolymer solution at a temperature between 30 and 150 C.

It is obvious that, without departing from the scope of the present invention, the hydrocarbon oil compositions can also contain other commonly used additives such as corrosion inhibitors, anti-emulsifying, anti-static agents, antioxidants, etc.
The following examples are given for information only and cannot be considered as limiting the scope and spirit of the invention.

Example
To a solution of 32 g. (9.87 10-2 mole) of stearyl acrylate, 11 g. (11.22 10-2 mole) of maleic anhydride and 10 g.

(8.92 10-2 mol) of diisobutylene in 250 cm3 of toluene, 0.5 g is added. azobisisobutyronitrile and the mixture is stirred at 900C for 6 hours.

100 cm3 of the solution are precipitated in an excess of methyl alcohol; the precipitate is isolated by filtration, washed with alcohol and dried under reduced pressure to constant weight.

 17 g are obtained in this way. of a terpolymer having a number average molecular mass equal to 4100 and containing approximately 48% by moles of stearyl acrylate, 32% by moles of maleic anhydride and 20% by moles of diisobutylene.

If 300 ppm of this terpolymer is added to an MANDJI atmospheric residue, the characteristics of which are given below
Density at 15 C (kg / 1): 0.958I
S (% weight): I, 86
Asphaltenes (% by weight): 2.80
Pour point (C): + 33
Kinematic viscosity at 500C: 1060 cst the pour point is lowered to + 150C.

 Furthermore, if we study the rheological behavior of an Egyptian crude oil using a rotational viscometer, we observe that the addition of 300 ppm of this terpolymer reduces the deformability threshold and the plastic viscosity.

Example 2
To 100 cm3 of the solution of Example 1, 3.8 g are added. (3.7 10-2 mol) of dimethylaminopropylamine and the mixture is stirred for 4 hours at 150 C. The terpolymer is then isolated by precipitation in methyl alcohol, as in Example 1,
The infrared spectrum of the modified terpolymer obtained under these conditions shows the disappearance of the absorption band due to the C = O bonds of the anhydride type, located initially around 1775 cm ~ l; on the other hand, we observe the appearance of a new absorption band located around 1705 1695 cm-1 and attributed to the formation of C = O bonds of imide type.

 The method for determining the dispersing or antiflocculating activity of the terpolymer thus imidated is based on its power to disperse the asphaltenes contained in a hydrocarbon oil. Asphaltenes are obtained by oxidizing a naphthenic oil in air, in the presence of traces of iron salt as catalyst. The oxidation is preferably carried out at 1750C for approximately 72 hours1 by passing a stream of air through the oil naphthenic, so as to form a coating which can be separated by centrifugation. If 2% by weight of this coating is added to a hydrocarbon oil solution containing 0.5% by weight of terpolymer and after stirring the mixture between 90 and 150 C for 2 hours the colored solution obtained remains clear at rest, which confirms the dispersing activity of the terpolymer with respect to asphaltenes.

 If 300 ppm of imidated terpolymer is added to an Indian crude oil, heated to 60 ° C., the flow temperature, initially at + 33 ° C., is lowered to + 180 ° C.

Example 3
Has a solution of 66 g. (20.37 10-2 mole) stearyl acrylate, 18 g. (9.78 10 2 mole) of 2-ethylhexyl acrylate, 12 g. (10.71 10-2 mol) of diisobutylene and 31 g (13.59 10-2 mol) of dibutyl maleate in 500 cm3 of diisopropylbenzene heated to 120 ° C., a solution of 1.2 is added over 2 hours g. of dicumyl peroxide in 20 cm3 of diisopropylbenzene and the heating is then prolonged at 120 C for 4 hours.

 The average molecular weight of the product obtained by precipitation of the mixture in methyl alcohol is 7,000.

 A sample of the crude solution in diisopropylbenzene is added to a waste fuel (vacuum residue of a desulphurized Arabian oil) having a flow temperature located around -40C; in the presence of 300 ppm of terpolymer, the flow temperature is lowered to - 15 C.

Example 4
A mixture containing 24 g. (21.43 10-2 mol) of diisobutylene and 40 g. 2I, 97 lo-2 mole) of maleimide (obtained by condensation of maleic anhydride with dimethylaminopropylamine) in 500 cm3 of diesel fuel having a distillation range, between 150 and 3700C, is heated to 900C. 500 cm3 of a diesel solution containing 32 g are gradually added thereto. (9.87 10-2 mole) stearyl acrylate, 50 g. (20.83 10-2 mole) of lauryl acrylate and 1.2 g. of azobisisobutyronitriîe. When the addition is complete, the stirring of the reaction mixture is continued at 900C for 4 hours.

 A sample of the solution thus obtained is added to the atmospheric residue MANDJI used in Example 1, having a flow temperature of + 330C; in the presence of 200 ppm of terpolymer, the flow temperature is lowered to +120 C.

Good dispersing power is observed during the asphaltenes test described in Example 2.

Example 5
Has a solution of 15 g. (10.56 10-2 mole) butyl methacrylate, 18 g. (9.78 10-2 mole) of 2-ethylhexyl acrylate, 20 g. (17.86 10-2 mole) of diisobutylene and 40 g. (40.82 10-2 mol) of fumaric anhydride in kerosene, 1 g is added. benzoyl peroxide. The mixture is gradually heated to 700C for 2 hours then to 900C for 2 hours and finally to 110 ° C for 2 hours. 216 g are then added. (0.8 mole) "Alol 18" (linear saturated monoalcohol having 18 carbon atoms) and -2.8 g. paratoluenesulfonic acid and the mixture is stirred at 150 ° C. for 4 hours, which allows an almost complete esterification of the anhydride functions by the Alfol.

160 ppm. of the esterified terpolymer make it possible to lower the flow temperature of an ARAMCO vacuum residue, from + 240C to + 15 C.

Example 6
Has a solution of 18.5 g. (21.51 10-2 mole) vinyl acetate, 34 g. (30.36 10-2 mole) of diisobutylene and 158 g. (42.93 10-2 mol) of monostearyl maleate, in 500 cm3 of diisopropylbenzene, 0.8 g is added. of benzoyl peroxide and the mixture is stirred at 700C for 4 hours, then at 190C for 2 hours.

A sample of the solution is mixed with an atmospheric residue MANDJI, so as to have a concentration of 600 ppm. terpolymer; the flow temperature is lowered to + 9 C.

If 0.1% terpolymer is added to crude oil
Egyptian having a flow temperature located around + 12 C, it is lowered to around - 180C.

Claims (13)

1. Composition of hydrocarbon oil comprising a major proportion of a hydrocarbon oil chosen from gas oils, domestic fuel oils, heavy fuels, fuels n02, residual fuels and crude oils, characterized in that it comprises a proportion at least a minor, a soluble terpolymer comprising (A) units corresponding to one of the general formulas

(respectively derived from a vinyl monoester or an acrylic monoester), in which R1 represents a hydrogen atom or an alkyl radical containing from 1 to 4 carbon atoms and R2 represents an alkyl radical containing from 1 to 30 carbon atoms carbon  (B) units, derived from at least one compound ;; t3-dicarboxylic acid with ethylenic unsaturation, and corresponding to one of the general formulas

in which, R3 and R4, identical or different, represent a hydrogen atom or a methyl radical, X and Y, identical or different, are chosen from the groups -OH, -OR5, -NH and-NHR5, R5 representing a monovalent organic radical derived from an organic compound containing at least one hydroxyl function and / or at least one amine function, and (C) units of formula

 derived from diisobutylene and having a number average molecular weight of about 500 to 200,000. 2. Hydrocarbon oil composition according to claim 1, characterized in that said terpolymer contains per 100 units, from 10 to 94 units (A), from 3 to 50 units (B) and from 3 to 40 units (C). 3. Hydrocarbon oil composition according to claim 2, characterized in that said terpolymer contains, per 100 units, from 40 to 80 units (A), from 10 to 35 units (B) and from 10 to 25 units (C). 4. Hydrocarbon oil composition according to one of claims 1 to 3, characterized in that the number-average molecular mass of said terpolymer is approximately 1,000 to 70,000. 5. Hydrocarbon oil composition according to one of claims 1 to 4, characterized in that the units (A) of said terpolymer are derived from at least one alkyl acrylate or methacrylate, the alkyl part of which contains from 1 to 30 atoms of carbon. 6. A hydrocarbon oil composition according to claim 5, characterized in that the units (A) of said terpolymers are derived from at least one methyl, butyl, etylhexyl, lauryl or stearyl acrylate or methacrylate. 7. Hydrocarbon oil composition according to one of claims 1 to 6, characterized in that the units (A) of said terpolymer are derived from vinyl acetate. 8. Composition of hydrocarbon oil according to one of claims 1 to 7, characterized in that the units (B) of said terpolymer are derived from at least one ethylenically unsaturated -dicarbo- xyl compound chosen from maleic anhydrides 1 fumaric, citraconic and mesaconic, the corresponding acids, the corresponding derivatives having at least one ester or amide function, and the corresponding imides optionally N-substituted. 9. A hydrocarbon oil composition according to claim 8, characterized in that the units (B) of said terpolymer are derived from maleic anhydride or maleic acid. 10. Hydrocarbon oil composition according to claim 9, characterized in that the units (B) of said terpolymer, derived from maleic anhydride or maleic acid have been reacted, at least for part of them , with at least one organic compound containing at least one function chosen from hydroxyl functions and amine functions. 11. A hydrocarbon oil composition according to claim 8, characterized in that the units (B) of said terpolymer are derived from at least one compounda, -dicarboxylic acid with ethylenic unsaturation chosen from alkyl maleates, maleimides and maleimides N -substituted 12. Hydrocarbon oil composition according to one of claims 1 to 11, characterized in that said terpolymer represents from 0.005 to 2% by weight of said composition. 13. A hydrocarbon oil composition according to claim 12, characterized in that said terpolymer represents from 0.01 to 0.5% by weight of said composition.