EP1658356B1 - Alkoxylated, cross-linked polyglycerols and use thereof as biodegradable demulsifier - Google Patents

Description

The present invention relates to the use of alkoxylated crosslinked polyglycerols for the splitting of water-oil emulsions, in particular in crude oil production.

Crude oil accumulates in its promotion as an emulsion with water. Before further processing of the crude oil these crude oil emulsions must be split into the oil and water content. For this purpose, one generally uses so-called petroleum splitters. Petroleum breakers are surface-active polymeric compounds capable of effecting, within a short time, the required separation of the emulsion components.

As petrol splitters are in U.S. 4,321,146 Alkylene oxide block copolymers and in U.S. 5,445,765 alkoxylated polyethyleneimines. These can be used as individual components, in mixtures with other emulsion breakers, or else as crosslinked products. Crosslinking is carried out, for example, by means of reactions of alkoxylated low molecular weight alcohols (such as, for example, glycerol or pentaerythrol) or alkoxylated alkylphenolformaldehyde resins with bifunctional compounds such as diepoxides or diisocyanates. Such crosslinked compounds are used in U.S. 5,759,409 and U.S. 5,981,687 disclosed.

The use of alkoxylated glycerin as a demulsifying ingredient in lubricating oils has been disclosed in US 5,256,064 DD-229 006 described. Here, glycerol is reacted with alkylene oxides to either a block copolymer or a random copolymer.

The use of alkoxylated di- and triglycerols as petroleum emulsion breakers has also been described ( U.S. 3,110,737 . US 2,944,982 such as U.S. 4,342,657 ).

Alkoxylated polyglycerols are known per se. They are described in the prior art for various applications. For example, in U.S. 5,502,219 alkoxylated polyglycerols esterified to produce a low calorie substitute for vegetable oils. In U.S. 4,061,684 For example, the alkoxylated polyglycerols were esterified and used as water-swelling gels. Alkoxylated polyglycerols reacted with alpha olefin epoxides act accordingly WO-98/03243 as a defoamer. Sulfation of alkoxylated polyglycerols leads to substances used in hair shampoos, such as U.S. 4,263,178 disclosed.

Alkoxylated polyglycerols have been used in DE 101 07 880 A1 disclosed as effective emulsion breakers.

The different properties (for example, asphaltene, paraffin and salinity, chemical composition of natural emulsifiers) and water content of various crude oils make it essential to further develop the existing oil splitters. In particular, a low metering rate and broad applicability of the oil separator to be used in addition to the desired higher efficiency from an economic and environmental point of view in the foreground. Furthermore, emulsion breakers are increasingly needed that have good biodegradability and low bioaccumulation to replace the alkylphenol-based products under discussion.

It was therefore the task of developing new petroleum breakers, which are superior to the already known alkoxylated polyglycerols in the action, can be used in even lower doses and have better biodegradability.

It has surprisingly been found that alkoxylated crosslinked polyglycerols show excellent action as petroleum breakers even at very low dosage. In addition, they showed significantly better biological Degradability (according to OECD 306) compared to conventional commercial emulsion breakers and alkoxylated non-crosslinked polyglycerols.

The invention therefore relates to the use of alkoxylated polyglycerols crosslinked with multifunctional electrophilic compounds and having a molecular weight of from 1000 to 100,000 units comprising from 5 to 100 glycerol units alkoxylated with C ₂ -C ₄ -alkylene oxide groups or a mixture of such alkylene oxide groups such that the crosslinked, alkoxylated polyglycerol has a degree of alkoxylation of from 1 to 100 alkylene oxide units per free OH group, to cleave oil / water emulsions in amounts of 0.0001 to 5 wt .-%, based on the oil content of the emulsion to be cleaved.

These alkoxylated crosslinked polyglycerols are obtainable from crosslinked polyglycerols having 5 to 100 glycerol units by alkoxylation of the free OH groups with a C ₂ -C ₄ -alkylene oxide or a mixture of such alkylene oxides in a molar excess, so that the alkoxylated crosslinked polyglycerol has the stated degree of alkoxylation.

The preparation of the polyglycerol is known in the art and is generally carried out by acid or alkali catalyzed condensation of glycerol. The reaction temperature is generally between 150 and 300 ° C, preferably at 200 to 250 ° C. The reaction is usually carried out at atmospheric pressure. As the catalyzing acids, for example, HCl, H ₂ SO ₄ , sulfonic acids or H ₃ PO ₄ are mentioned, as bases NaOH or KOH, which are used in amounts of 0.1 to 50 wt .-%, based on the weight of the reaction mixture. The condensation generally takes 3 to 10 hours. Polyglycerols can be represented by formula 1.

In formula 1, n is the degree of condensation, ie the number of glycerol units. n increases with increasing reaction time and is determined by OH number.
In the next step, the polyglycerols thus prepared are crosslinked with di- or multifunctional, electrophilic compounds. This achieves a very easily controllable increase in the molecular weight of the polyglycerols. Suitable crosslinkers include di- or polyglycidyl ethers, di- or polyepoxides, di- or polycarboxylic acids, carboxylic anhydrides, di- or polyisocyanates, dialkoxydialkylsilanes, trialkoxyalkylsilanes and tetraalkoxysilanes. The crosslinking is carried out as known in the art.

The following crosslinkers are particularly preferred:

Bisphenol A diglycidyl ether, butane-1,4-diol diglycidyl ether, hexane-1,6-diol diglycidyl ether, ethylene glycol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, resorcinol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, Glycerinpropoxylattriglycidylether, polyglycerol polyglycidyl ether, p-Aminophenoltriglycidylether, polypropylene, Pentaerythritteträglycidylether, sorbitol polyglycidyl ether, trimethylolpropane triglycidyl ether, Castoröltriglycidylether, Diaminobiphenyltetraglycidyl ether, soybean oil epoxide, adipic acid, maleic acid, phthalic acid, maleic anhydride, succinic anhydride, dodecylsuccinic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, dimethoxydimethylsilane, diethoxydimethylsilane, tetraalkoxysilanes, toluene diisoyanate, diphenylmethane diisocyanate.

The crosslinkers or chemically related compounds mentioned are preferably used in the range of 0.1-10, more preferably 0.5-5 and especially 1.0-2.5% by weight, based on the polyglycerol.

As a rule and particularly preferably, the crosslinking step is carried out after the glycerol condensation and before the alkoxylation. Crosslinking after glycerol condensation and subsequent alkoxylation can According to the invention also be carried out.
The crosslinked polyglycerols obtained from glycerol condensation and subsequent crosslinking are then alkoxylated with one or more C ₂ -C ₄ -alkylene oxides, preferably ethylene oxide (EO) or propylene oxide (PO). The alkoxylating agent is used in molar excess. The alkoxylation is carried out, as known in the art, by reacting the polyglycerols with an alkylene oxide under elevated pressure of generally 1.1 to 20 bar at temperatures of 50 to 200 ° C. The alkoxylation takes place on the free OH groups of the polyglycerols. So much alkylene oxide is used that the average degree of alkoxylation is between 1 and 100 alkylene oxide units per free OH group. By medium degree of alkoxylation is meant here the average number of alkoxy units which is attached to each free OH group. It is preferably from 2 to 70, especially from 5 to 50, especially from 20 to 40.

Preferably, the alkoxylation is carried out first with PO and then with EO. The ratio of EO to PO in the alkoxylated polyglycerol is preferably between 1: 1 and 1:10. According to the invention, however, the alkoxylation can also be carried out in the reverse order, first EO then PO or with a mixture of PO and EO.

The polyglycerol obtained after condensation, subsequent crosslinking and alkoxylation preferably has a molecular weight of from 3,000 to 50,000 units, in particular from 5,000 to 30,000 units, especially from 8,000 to 25,000.

The alkoxylated crosslinked polyglycerols prepared by the process described are exemplified in the case of the crosslinker phthalic anhydride by the following structure (formula 2):

(AO) _k , _{l, m} O are the alkoxylated OH radicals in which AO is a C ₂ -C ₄ -alkylene oxide unit and k, l, m are the degrees of alkoxylation. n stands for the degree of condensation of glycerol. n is preferably a number from 5 to 50, more preferably 8 to 30, especially 10 to 20.
A preferred subject of the present invention is the use of the alkoxylated polyglycerols as a splitter for oil / water emulsions in petroleum production.

For use as petroleum breakers, the cross-linked alkoxylated polyglycerols are added to the water-oil emulsions, preferably in solution. As solvents for the crosslinked alkoxylated polyglycerols, paraffinic or aromatic solvents are preferred. The crosslinked alkoxylated polyglycerols are used in amounts of 0.0001 to 5, preferably 0.0005 to 2, in particular 0.0008 to 1 and especially 0.001 to 0.1 wt .-% based on the oil content of the emulsion to be cleaved.

Examples example 1 Preparation of pentadecaglycerin

In a 250 ml three-necked flask with contact thermometer, stirrer and Wasserauskreiser 100.0 g of glycerol and 3.7 g of NaOH (18%) were mixed. With stirring and nitrogen purge, the reaction mixture was heated rapidly to 240 ° C. At this temperature, the reaction water was distilled off over 8 h. The product was rotary evaporated to dryness on a rotary evaporator (Yield: 67.3 g) and the molecular weight was analyzed by GPC (M ^* ≈ 1100 g / mol, standard polyethylene glycol). The chain length n was determined by OH number.

Example 2 Crosslinking of pentadecaglycerol with bisphenol A diglycidyl ether

In a 500 ml three-necked flask equipped with a contact thermometer, stirrer and reflux condenser, 250.0 g of pentadecaglycerol were heated to 80 ° C. with gentle nitrogen purge. At this temperature, 13.2 g of bisphenol A diglycidyl ether (80% solution in an aromatic solvent) were added dropwise rapidly. Thereafter, the reaction temperature was raised to 120 ° C and the reaction mixture was allowed to stir for 8 h until by titration of the epoxide no unreacted diglycidyl ether could be detected. The product was rotary evaporated to dryness (yield: 260.0 g) and the molecular weight was analyzed by GPC (M * ≈ 2600 g / mol, standard polyethylene glycol).

Example 3 Crosslinking of pentadecaglycerol with dodecylsuccinic anhydride

100.0 g of pentadecaglycerol, 1.5 g of alkylbenzenesulfonic acid and 2.7 g of dodecylsuccinic anhydride were initially charged at room temperature in a 250 ml three-necked flask with contact thermometer, stirrer and water separator. Thereafter, the reaction mixture was heated to 165 ° C and allowed to stir for a further 8 h at this temperature until no more water of reaction formed in the water (reaction control: acid number). The product was rotary evaporated to dryness (yield: 102.0 g) and the molecular weight was analyzed by GPC (M ^* ≈ 2450 g / mol, standard polyethylene glycol).

Example 4 Crosslinking of pentadecaglycerol with toluene-2,4-diisocyanate

In a 250 ml three-necked flask equipped with a contact thermometer, stirrer and reflux condenser, 100.0 g of pentadecaglycerol were heated to 60 ° C. under a slight nitrogen purge. Thereafter, 2.4 g of toluene-2,4-diisocyanate were slowly added dropwise at this temperature. The reaction temperature was raised to 100 ° C and the reaction mixture stirred for a further 8 h at this temperature (reaction control: isocyanate number). The product was rotary evaporated to dryness (yield: 102.2 g) and the molecular weight was analyzed by GPC (M ^* ≈ 2380 g / mol, standard polyethylene glycol).

Example 5 Preparation of decaglycerin

In a 250 ml three-necked flask with contact thermometer, stirrer and Wasserauskreiser 100.0 g of glycerol and 3.7 g of NaOH (18%) were mixed. With stirring and nitrogen purge, the reaction mixture was heated rapidly to 240 ° C. At this temperature, the reaction water was distilled off over 5 h. The product was rotary evaporated to dryness (yield: 74.9 g) and analyzed by GPC (M ^* ≈ 730 g / mol). The chain length n was determined by OH number.

Example 6 Crosslinking of decaglycerin with bisphenol A diglycidyl ether

In a 250 ml three-necked flask with contact thermometer, stirrer and reflux condenser 100.0 g of decaglycerol were heated to 80 ° C with a slight nitrogen purge. At this temperature, 3.0 g of bisphenol A diglycidyl ether (80% solution in an aromatic solvent) was added dropwise rapidly. Thereafter, the reaction temperature was raised to 120 ° C and the reaction mixture was allowed to stir for 8 h until by titration of the epoxide no unreacted diglycidyl ether could be detected. The product was rotary evaporated to dryness (yield: 102.3 g) and the molecular weight was analyzed by GPC (M ^* ≈ 1530 g / mol, standard polyethylene glycol).

Example 7 Crosslinking of decaglycerin with dodecylsuccinic anhydride

100.0 g of decaglycerol, 1.5 g of alkylbenzenesulfonic acid and 2.5 g of dodecylsuccinic anhydride were initially charged at room temperature in a 250 ml three-necked flask with contact thermometer, stirrer and water separator. Thereafter, the reaction mixture was heated to 165 ° C and allowed to stir for a further 8 h at this temperature until no more water of reaction formed in the water (reaction control: acid number). The product was rotary evaporated to dryness (yield: 101.8 g) and the molecular weight was analyzed by GPC (M ^* ≈ 1420 g / mol, standard polyethylene glycol).

Example 8 Crosslinking of decaglycerol with toluene-2,4-diisocyanate

In a 250 ml three-necked flask equipped with a contact thermometer, stirrer and reflux condenser, 100.0 g of decaglycerol were heated to 60 ° C. with gentle nitrogen purge. Thereafter, 2.4 g of toluene-2,4-diisocyanate were slowly added dropwise at this temperature. The reaction temperature was raised to 100 ° C and the reaction mixture stirred for a further 8 h at this temperature (reaction control: isocyanate number). The product was rotary evaporated to dryness (yield: 102.1 g) and the molecular weight was analyzed by GPC (M ^* ≈ 1650 g / mol, standard polyethylene glycol).

Oxalkylation of the crosslinked polyglycerols ethylene oxide

The crosslinked polyglycerols described above were introduced into a 1 l glass autoclave and the pressure in the autoclave was brought to about 10 bar with nitrogen. 0.2 bar overpressure set. It was slowly heated to 140 ° C and after reaching this temperature, the pressure is again set to 0.2 bar overpressure. Thereafter, the desired amount of EO (see Table 1) was added at 140 ° C, the pressure should not exceed 4.5 bar. After completion of EO addition was allowed to react for 30 minutes at 140 ° C.

propylene oxide

The crosslinked polyglycerols described above were introduced into a 1 l glass autoclave and the pressure in the autoclave was adjusted to about 0.2 bar overpressure with nitrogen. It was slowly heated to 130 ° C and after reaching this temperature, the pressure is again set to 0.2 bar overpressure. Thereafter, the desired amount of PO was metered in at 130 ° C. (see Table 1), the pressure not exceeding 4.0 bar. After completion of the addition of PO was allowed to react for 30 minutes at 130 ° C.

The degree of alkoxylation was determined by means of ¹³ C-NMR.

Determination of the splitting efficiency of petroleum emulsion separators

To determine the effectiveness of an emulsion breaker, the water separation from a crude oil emulsion per time and the drainage and desalting of the oil was determined. In each case, 100 ml of the crude oil emulsion were introduced into breaker glasses (conically tapered, screwable, graduated glass bottles), in each case a defined amount of the emulsion separator was metered with a micropipette just below the surface of the oil emulsion, and the breaker was mixed into the emulsion by intensive shaking. Thereafter, the breaker glasses were placed in a tempering bath (30 ° C and 50 ° C) and followed by the separation of water.

During and after completion of emulsion splitting, samples were taken from the oil from the upper part of the splitter glass (so-called top oil) and the water content according to Karl Fischer and the salt content were determined by conductometry.

In this way, the new splitters were assessed after water separation and dewatering and desalination of the oil.

Cleavage action of the splitter described

Origin of crude oil emulsion: Holzkirchen Probe 3, Germany Water content of the emulsion: 46% Salinity of the emulsion: 5% Demulgiertemperatur: 50 ° C Table 1: Effectiveness of alkoxylated crosslinked polyglycerols as emulsion breakers in comparison with the corresponding alkoxylated uncrosslinked polyglycerol and Dissolvan 4738 (dosing rate 20 ppm) Water separation [ml] per time [min] 5 10 20 30 45 60 90 120 180 Water in the top oil [%] Salt in top oil [ppm] Product of 1 + 30 PO + 20 EO (comparison) 2 6 12 21 28 36 40 42 43 0.85 156 Product of 2 + 30 PO + 20 EO 4 10 22 30 38 43 46 46 46 0.15 35 Product of 3 + 30 PO + 20 EO 6 13 27 35 42 45 46 46 46 0.13 25 Product of 4 + 30 PO +20 EO 4 11 24 33 40 44 45 46 46 0.31 56 Product of 5 + 40 PO + 30 EO (comparison) 0 4 10 19 26 34 40 42 42 0.92 189 Product of 6 + 40 PO + 30 EO 3 12 25 33 40 44 46 46 46 0.11 12 Product of 7 + 40 PO + 30 EO 2 5 12 26 37 42 45 45 46 0.19 21 Product of 8 + 40 PO + 30 EO 5 14 28 35 42 43 45 46 46 0.15 19 Standard: Dissolvan 4738 (comparative) 0 0 0 5 11 25 32 38 39 0.97 220 Biodegradability of alkoxylated crosslinked polyglycerols ( closed bottle test according to OECD 306) in comparison to the corresponding alkoxylated uncrosslinked polyglycerol and Dissolvan 4738 Biodegradability [%] according to 14 days 28 days Product of 1 + 30 PO + 20 EO (comparison) 16.5 22.4 Product of 2 + 30 PO + 20 EO 33.5 46.1 Product of 3 + 30 PO + 20 EO 40.6 50.3 Product of 4 + 30 PO +20 EO 38.5 53.4 Product of 5 + 40 PO + 30 EO (comparison) 10.5 19.5 Product of 6 + 40 PO + 30 EO 42.7 63.5 Product of 7 + 40 PO + 30 EO 38.2 58.3 Product of 8 + 40 PO + 30 EO 33.5 54.7 Standard: Dissolvan 4738 (comparative) 20.5 27.5 Reference (sodium benzoate) (comparative) 62.5 81.4

Claims (8)

1. The use of alkoxylated polyglycerols, crosslinked with multifunctional electrophilic compounds with a molecular weight of from 1000 to 100 000 units which comprise 5 to 100 glycerol units which are alkoxylated with C₂-C₄-alkylene oxide groups or a mixture of such alkylene oxide groups so that the crosslinked alkoxylated polyglycerol has a degree of alkoxylation of from 1 to 100 alkylene oxide units per free OH group, for demulsifying oil/water emulsions in amounts of from 0.0001 to 5% by weight, based on the oil content of the emulsion to be demulsified.
2. The use as claimed in claim 1, in which the number of glycerol units is between 5 and 50.
3. The use as claimed in claim 1 and/or 2, where the alkoxylated, crosslinked polyglycerols have a molecular weight of from 3000 to 50 000 units.
4. The use as claimed in one or more of claims 1 to 3, in which the average degree of alkoxylation is between 1 and 70 alkylene oxide units per free OH group.
5. The use as claimed in one or more of claims 1 to 4, in which the alkylene oxide is ethylene oxide or propylene oxide.
6. The use as claimed in one or more of claims 1 to 5, in which a coalkoxylation with ethylene oxide and propylene oxide in the ratio of from 1:2 to 1:10 is present.
7. The use as claimed in one or more of claims 1 to 6, where the crosslinking of the polyglycerols takes place by means of bisphenol A diglycidyl ether, butane-1,4-diol diglycidyl ether, hexane-1,6-diol diglycidyl ether, ethylene glycol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, resorcinol diglycidyl ether, glycerol diglycidyl ether, glycerol triglycidyl ether, glycerol propoxylate triglycidyl ether, polyglycerol polyglycidyl ether, p-aminophenol triglycidyl ether, polypropylene glycol diglycidyl ether, pentaerythritol tetraglycidyl ether, sorbitol polyglycidyl ether, trimethylolpropane triglycidyl ether, castor oil triglycidyl ether, diaminobiphenyl tetraglycidyl ether, soya oil epoxide, adipic acid, maleic acid, phthalic acid, maleic anhydride, succinic anhydride, dodecylsuccinic anhydride, phthalic anhydride, trimellitic anhydride, pyromellitic anhydride, dimethoxydimethylsilane, diethoxydimethylsilane, toluene diisocyanate, diphenylmethane diisocyanate.
8. The use as claimed in one or more of claims 1 to 7, where the crosslinking step is carried out after the alkoxylation of the polyglycerols.