EP0413279B1 - Use of reaction products from alcenylspirodilactones and amines as paraffindispersants - Google Patents

Description

Use of reaction products of alkenyl spirobislactones and amines as paraffin dispersants

Mineral oil middle distillates of different provenances usually have quite different levels of n-paraffins. In diesel fuel, long-chain paraffins (C₁₁-C₃₃) are advantageous on the one hand because they contribute to improving the cetane number, but on the other hand they are disadvantageous because they restrict the fluidity of the fuel as the temperature drops.
This reduction in fluidity is based on the crystallization of the paraffins into plate-shaped crystals and the development of a three-dimensional network structure (gel structure). When operating diesel engines or heating systems at low temperatures, these crystals generally do not pass through the respective filter units and therefore sooner or later lead to a blockage of the fuel flow. This may result in trouble starting or starting the diesel engine, or it may cause the fuel preheating system to fail.

It is known that numerous additives are capable of improving the cold flow behavior or the filterability. For example, US Pat. No. 3,961,916 describes the use of a mixture of copolymers to control the size of the paraffin crystals and, according to GB-A 1 263 152, the size of the paraffin crystals is to be controlled by using a copolymer with a low chain branching. Furthermore, the US-A 3 048 479 describes the use of copolymers of ethylene and C₁-C₅ vinyl esters (for example vinyl acetate) as flow improvers for fuels such as diesel and heating oil.

The improvement in the cold flow behavior, which is achieved by the incorporation (cocrystallization) of these known additives during wax crystal growth, is based on a modification of the size and shape of the wax crystals formed, which then no longer clog the pores of the filters, but instead form a porous filter cake and one allow more or less unhindered passage of the remaining liquid components.

Most of these flow improvers, however, are now unable to prevent sedimentation of the wax crystals once formed. The paraffin crystals have a slightly higher density than the surrounding fuel itself and therefore usually sediment according to the Stokes law. Since the tendency to sedimentation also depends on the crystal size and the crystal shape, a reduction in the crystal size in the colloidal area should significantly slow down the sedimentation efforts of the paraffin crystals.

This is precisely the principle followed in a number of recent patents. Thus, EP-A-0 203 812, 0 272 889 describe substances with a "wax anti-settling" effect, i.e. The wax crystals once formed should then remain homogeneously distributed in the middle distillate and not sediment.

The type of product is usually a multi-component mixture consisting, for example, of tallow fatty amine-phthalic anhydride reaction products, alkyl diphenyl ethers, alkyl naphthalenes and small amounts of a flow improver. D-OS 3 634 082, 3 634 083 and EP-A-0 261 959 also describe the use of reaction products of the anhydride of orthosulfobenzoic acid with alkylamines as a paraffin dispersant.

Practice-oriented tests have shown, however, that the components described have sufficient action with many middle distillates, but fail with some diesel oils.

There is therefore still a need for highly effective paraffin dispersants for middle distillates with the broadest possible effect.

Surprisingly, it has now been found that certain reaction products of alkenyl spirobislactones with certain amines have excellent activity as paraffin dispersants in many middle distillates, even at temperatures below -20 ° C.

wobei R jeweils C₈-C₂₀₀-, vorzugsweise C₁₀-C₂₀-Alkenyl bedeuten, mit Aminen der Formel

        NR¹R²R³


wobei R¹, R² und R³ gleich oder verschieden sein können und mindestens eine dieser Gruppen R¹, R² oder R³ C₈-C₃₆-Alkyl, C₈-C₃₆-Alkenyl oder Cyclohexyl und die übrigen Gruppen Wasserstoff oder eine Gruppe der Formel -(A-O)_xH oder -(CH₂)_n-NYZ, A= -C₂H₄- und/oder -C₃H₆-, x eine Zahl von 1 bis 20, n 2 oder 3 und Y und Z gleich oder verschieden sein können und Wasserstoff oder eine Gruppe der Formel (-A-O)_xH bedeuten, als Paraffindispergatoren in Mitteldestillaten und Erdöl.The invention thus relates to the use of reaction products of alkenyl spirobislactones of the formula

where R is in each case C₈-C₂₀₀-, preferably C₁₀-C₂₀-alkenyl, with amines of the formula

NR¹R²R³


where R¹, R² and R³ may be the same or different and at least one of these groups R¹, R² or R³ C₈-C₃₆-alkyl, C₈-C₃₆-alkenyl or cyclohexyl and the other groups are hydrogen or a group of the formula - (AO) _x H or - (CH₂) _n -NYZ, A = -C₂H₄- and / or -C₃H₆-, x can be a number from 1 to 20, n 2 or 3 and Y and Z can be identical or different and are hydrogen or a group of the formula ( -AO) _x H mean as paraffin dispersants in middle distillates and petroleum.

The alkenylspirobislactones serving as starting compounds are prepared by the process described in US Pat. No. 4,532,058 by decarboxylation of alkenylsuccinic anhydrides in the presence of bases.

These alkenylspirobislactones are reacted with the amines of the formula given to give the products to be used according to the invention. The reaction can optionally be carried out in the absence of a solvent or in the presence of an inert, non-polar, organic solvent.

In the reaction with the alkenyl spirobislactones, either a certain amine with the abovementioned radicals can be used, but mixtures of different amines can also be used simultaneously. The molar ratio of alkenyl spirobislactone: amines is in the range from 1: 1 to 1: 2.5, preferably 1: 2, the reaction temperatures are 60-200 ° C., preferably 80-120 ° C.

The reaction products described above are suitable as paraffin dispersants, preferably in middle distillates such as diesel fuels or motor oils, but also in crude oils. They are usually used in amounts of 150 to 500 ppm. These paraffin dispersants are preferably not dosed alone, but combined with customary, known flow improvers, for example ethylene-vinyl acetate copolymers. The amount of such flow improvers is usually 50 to 600, preferably 300 ppm.

General information on the production of alkenyl spirobislactones

2 moles of an alkenyl succinic anhydride are heated in the presence of 0.5% by weight of KF at 220-230 ° C for 6 hours, with CO₂ escaping. 1 mol of the alkenyl spirobislactone is obtained.

example 1 Implementation of dodecenyl spirobislactone with tallow fatty amine and ditallow fatty amine

488 g (1 mol) of dodecenyl spirobislactone is stirred for 2 hours at 80 ° C. with a mixture of 260 g (1 mol) of tallow fatty amine and 495 g (1 mol) of ditallow fatty amine. Then 840 g of Shellsol AB (aromatic hydrocarbon mixture) are added and the mixture is stirred for 20 minutes. and bottles. About 2080 g of a brown oil with an active ingredient content of 60% are obtained.

Example 2 Implementation of tetradecenyl spirobislactone with tallow fatty alkyl dihydroxyethylamine and ditallow fatty amine

544 g (1 mol) of tetradecenyl spirobislactone is first reacted with 360 g (1 mol) of tallow fatty alkyl dihydroxyethylamine at 120 ° C. for 1 hour, then 495 g (1 mol) of ditallow fatty amine are added and the mixture is stirred at 80 ° C. for a further 2 hours. Then 930 g of Shellsol AB are added and the mixture is stirred for 20 min. and bottles. About 2330 g of brown oil with an active content of 60% are obtained.

Example 3 Implementation of polyisobutenyl spirobislactone with tallow fat propylene diamine and dicyclohexylamine

756 g (1 mol) of polyisobutenyl spirobislactone (R = C₂₀H₃₉-C₂₄H₄₇) (which was produced by Decarboxylation of 2 moles of polyisobutenyl succinic anhydride with an average molecular weight of 400) is stirred for 2 hours at 100 ° C. with a mixture of 518 g (1.5 moles) of tallow fat propylene diamine and 363 g (0.5 moles) of dicyclohexylamine. Then 1090 g of Shellsol AB are added and the mixture is stirred for 20 min. and fills up. About 2700 g of brown oil containing 60% active ingredient are obtained.

Application part

In contrast to the determination of the limit value of the filterability (CFPP, IP 309 / DIN 51 428), there has so far been no analog test method for testing the paraffin dispersing effect.

In addition to a purely optical assessment of the degree of sedimentation, microscopic examinations of the crystal size and the use of analytical methods (DSC etc.) are used.

Since the sedimentation rate can be seen as a function of the crystal size and this in turn is influenced by the cooling rate, the CFPP test is ruled out as a criterion for testing the effectiveness of a paraffin dispersant because the oil sample is cooled too quickly.

As is well known, rapid cooling leads to a large number of small paraffin crystals, whereas with a slow cooling rate the number of paraffin crystals formed is considerably lower and, with the same amount of paraffin, the crystals are significantly larger.

• Kristallgröße/-form
• Temperatur
• Zeit

An attempt was made to take this into account using the laboratory test procedure described below. In general, three parameters are important for the sedimentation behavior of the paraffin crystals:

• Crystal size / shape
• temperature
• time

After extensive preliminary tests, it was found that the dispersing effect of various additives can be compared clearly and with readily reproducible results in a 72-hour cold test (temperature profile see FIG. 1). All refrigeration tests were carried out in a programmable refrigeration cabinet from Heraeus-Vötsch.

Cold test characteristics

Duration:

72 hours

Temperatures

Beginning:

+ 20 ° C

after 24 hours:

- 13 ° C

v. 24-72 hours:

- 13 to - 20 ° C

The End:

- 13 ° C

Cooling rate:

1-2 ° C / h

Sample volume:

100 ml

V_sed = Volumen des sedimentierten Anteils der Probe,
V_ges = Volumen der gesamten Probe.After the end of the cold test, the first step is an optical (visual) assessment of the oil pattern. The paraffin sedimentation is in this case visually the so-called in a known manner by determining, WDI (W ax D ispersion I ndex) characterized. $$\text{WDI =}\frac{{\text{V}}_{\text{sed}}}{{\text{V}}_{\text{total}}}\text{× 100}$$

V _sed = volume of the sedimented part of the sample,
V _tot = volume of the entire sample.

An optimal paraffin dispersion, recognizable by a homogeneously cloudy oil pattern, is given with a WDI 100. Values below 100 indicate paraffin sedimentation with simultaneous clarification (increased transparency) of the oil sample. Underlined WDI values indicate partial wax sedimentation; a small measured value indicates favorable behavior.

The optical characterization of the dispersion behavior is followed by a two-part division of the sample (volume: 100 ml). To do this, carefully remove (temp .: -13 ° C) 50 ml of the oil sample using a pipette. The pipette is immersed just below the surface and adjusted from top to bottom as the sample volume decreases. Both the 50 ml sample taken and the remaining 50 ml soil phase are then measured for cloud point (CP) and CFPP. As expected, the CP values of the two phases are approximately the same, indicating optimal dispersion of the wax crystals (WDI 100) or partial sedimentation. In the case of clearly recognizable paraffin sedimentation (WDI below 100), there are sometimes CP differences of more than 10 ° C (see examples); it also becomes clear that the CFPP results do not reflect the difference between good and bad dispersion as clearly as it does for the CP.

The measured values obtained with various oils are summarized in the following overview.

CP:

Cloud Point;

CFPP:

Cold Filter Plugging Point;

IBP:

Initial Boiling Point;

FBP:

Final Boiling point

The additives F 1 and F 2 mentioned in the test examples are flow improvers of the ethylene-vinyl acetate copolymer type (Dodiflow®3744 or Dodiflow®3905), PD A stands for the paraffin dispersant corresponding to Preparation Example 1 above .

CP:

Cloud point;

CFPP:

Cold filter plugging point;

IBP:

Initial boiling point;

FBP:

Final boiling point

Claims (5)

1. A process for improving the flowability of middle distillates and crude oil at low temperatures, which comprises adding to the middle distillates or crude oil a product of the reaction of alkenyl-spirobislactones of the formula

   

   in which R is in each case C₈-C₂₀₀-alkenyl, with amines of the formula
   
           NR¹R²R³
   
   in which R¹, R² and R³ may be identical or different and at least one of these groups R¹, R² or R³ is C₈-C₃₆-alkyl, C₈-C₃₆-alkenyl or cyclohexyl and the other groups are hydrogen or a group of the formula -(A-O)_xH or -(CH₂)_n-NYZ, A is -C₂H₄- and/or -C₃H₈-, x is a number from 1 to 20, n is 2 or 3 and Y and Z may be identical or different and are hydrogen or a group of the formula (-A-O)_xH.
2. The process as claimed in claim 1, wherein the reaction products are added in amounts of from 50 to 600 ppm.
3. The process as claimed in claim 1, wherein customary flow improvers are additionally added.
4. The process as claimed in claim 1, wherein the reaction products which are added are those obtained by reacting alkenyl-spirobislactone and amine in the ratio of 1:1 to 1:2.5.
5. The process as claimed in claim 1, wherein the reaction products which are added are those obtained by reacting alkenyl-spirobislactone and amine at 60 to 200°C.

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