GB2174096A - Copolymers of polyoxyalkylene ethers and acrylic or methacrylic esters and their use as demulsifiers for petroleum containing water - Google Patents

Abstract

Copolymers of (A) one or more polyoxyalkylene ether(s) of allyl or methallyl alcohol of the general formula <IMAGE> n = integer >/= 2, R<1> = allyl or methallyl radical, R<2> = hydrogen or optionally halogenated hydrocarbon radical with 1 to 30 carbon atoms, with (B) acrylic and/or methacrylic acid alkyl esters containing 1 to 20 carbon atoms in the alkyl radical, or and optionally (C) acrylic and/or methacrylic acid or acrylamide and/or methacrylamide, may be used as demulsifiers for crude oil containing water in usual quantities. The new copolymers may be used optionally mixed with other demulsifiers, in particular alkoxylated novolaks (b) and copolymers which are obtainable by copolymerization of one or more polyoxyalkylene ether(s) of allyl or methallyl alcohol of the above formula, with vinyl esters of alkyl monocarboxylic acids whose alkyl radical contains 1 to 4 carbon atoms or mixtures thereof with up to 50 mole % acrylic or methacrylic acid alkyl esters, whose alkyl radical contains 1 to 20 carbon atoms.

Description

SPECIFICATION Copolymers of polyoxyalkylene ethers and acrylic or methacrylic esters and their use as demulsifiers for petroleum containing water On extraction a large part of crude petroleum contains more or less large quantities of water in emulsified form. Emulsions of this type, which predominantly occur as water/oil emulsions, have to be decomposed into their phases since the salt water contained in the emulsion would be troublesome in the further processing of the petroleum, in particular during transport and during distillation.

The separation of such crude petroleum emulsions is achieved either by allowing to settle, heat treatment, centrifuging, by the application of electric fields or by the addition of demulsifiers or the combination of several of these methods.

The extracted crude petroleum emulsions are, however, usually too stable to be broken by sedimentation, filtration, centrifuging or heating alone. On the other hand, some emulsifiers effect a separation of the emulsion even in small concentrations.

The requirements to be imposed on an effective demulsifier are diverse and as a rule are not fulfilled by one compound. A demulsifier should have the following combination of properties: The demulsifying agent should be effective in as small quantitites as possible. The activity should be as independent of temperature as possible.

The demulsifying process should take place as quickly as possible.

The separation of the crude oil into an aqueous and an oil phase should take place with high selectivity, i.e. the separated aqueous layer should contain no petroleum or as little petroleum as possible, and the oil phase should likewise be as free as possible of water, of inorganic and organic sediments. Furthermore, the emulsion situated in the boundary region of the water and oil phase, the so-called intermediate phase, should occupy as small a volume as possible.

The demulsifying agent should be as universally usable as possible, i.e. it should have as low a specificity to petroleum as possible. The demulsifying agent should therefore display its demulsifying properties independently of the provenance of the petroleum.

Interface-active compounds for the demulsification of crude oil have already been proposed in a large number, these demulsifiers having various chemical structures. Thus, alkyl sulphates and aikylaryl sulphonates and also petroleum sulphonates in the form of the amine salts have already been used as demulsifiers. Furthermore, addition products of ethylene oxide to suitable compounds containing an active hydrogen atom such as, for example alkyl phenols, castor oil, fatty acids, fatty alcohols and aldehyde resins, have been used. Appropriate data are contained, for example, in the book "Oberflächenaktive Anlagerungsprodukte des Ethylenoxids" ("Surface Active Addition Products of Ethylene Oxide") by N.

Schtinfeld, Wissenschaftliche Verlagsgesellschaft mbH, Stuttgart, 1959, page 295.

From the German Patent Specification 3,338,923 the use as demulsifiers in usual quantities for petroleum containing water is known of copolymers which are obtainable by copolymerization of a) one or more polyoxyalkylene ether(s) of allyl and/or methallyl alcohol of the general formula

n = integer > 5, Ri = allyl or methallyl radical, R2 = hydrogen or optionally halogenated hydrocarbon radical containing 1 to 30 carbon atoms, with b) vinyl esters of C - C4 - alkyl monocarboxylic acids or b1) mixtures thereof containing up to 50 mole % of acrylic or methacrylic acid alkyl esters whose alkyl radical contains 1 to 20 carbon atoms, b2) it being possible for up to 15 mole % of the alkyl radicals to be unsaturated, and the quotient of the mean molecular weight of the polyoxyalkylene ethers, corresponding to their molar proportions, and of the number of moles of the other compounds to be copolymerized being 20 to 100.

These copolymers have the advantage of being relatively unspecified, i.e. they are suitable as demulsifiers for petroleum of various provenance. They further have the advantage of achieving the breaking of the crude oil into an aqueous and an oil phase rapidly and at the same time of performing the breaking quantitatively with the result that the oil phase contains only very small quantities of water and the aqueous phase contains only very small quantities of petroleum. However, it emerged, in particular when only small quantities of acrylic or methacrylic acid alkyl esters were used as comonomers, that on prolonged storage, solutions of the polymers in organic solvents such as, for example toluene, exhibited phase separations which possibly indicate the presence of a mixture of copolymers whose components are incompatible with each other.It was possible to prevent these incompatibilities by the use of methanol/water mixtures as solvents. However, the use of mixtures of this type is not desired on account of the low flash point of methanol.

The present invention is therefore based on the object of finding, as an extension of the copolymers described in German Patent Specification 3,338,923, such polymers which are suitable as petroleum de mulsifiers and which do not exhibit these phase separations, but are nevertheless usable in an exceptional manner as petroleum demulsifiers.

It has been found that polymers composed in a particular manner combine in themselves the required properties. The present invention provides a copolymer which is soluble or readily dispersible in toluene and is obtained by copolymerization of a1) one or more polyoxyalkylene ether or allyl or methallyl alcohol of the general formula

in which n is an integer ~ 2, R' is allyl or methallyl, R2 is hydrogen or optionally halogenated hydrogen containing 1 to 30 carbon atoms, with a2) an acrylic and/or methacrylic acid alkyl ester containing 1 to 20 carbon atoms in the alkyl group or mixtures thereof with a2,) up to 20 mole % acrylic and/or methyacrylic acid or a22) up to 20 mole % acrylamide and/or methacrylamide, and the quotient of the mean molecular weight of the polyoxy-alkylene ether, corresponding to their molar proportion, and of the number of moles of the other monomers to be copolymerized being 20 to 150.

b) The copolymer may be mixed with a toluene-soluble alkylene oxide addition production of an alkyl phenol formaldehyde novolak, the alkyl group being straight-chain or branched and containing 1 to 25 carbon atoms and/or c) a copolymer which is obtainable by copolymerization of c,) one or more polyoxalkylene ether of allyl or methallyl alcohol of the general formula

in which n, R', R2 are defined as above, with c2) vinyl esters of alkyl monocarboxylic acids whose alkyl group contains 1 to 4 carbon atoms, or mixtures thereof containing up to c2,) 50 mole % acrylic or methacrylic acid alkyl esters whose alkyl radical contains 1 to 20 carbon atoms, c22) it being possible for up to 15 mole % of the alkyl radicals to be unsaturated, and the quotient of the mean molecular weight of the polyoxyalkylene ethers, corresponding to their molar proportion, and the number of moles of the other monomers to be copolymerized being 20 to 100, the weight ratio of the components a : b : c being from 1 : 0: O to 1 : 4 : 4.

This copolymer or mixture of polymers may be used in demulsifying crude oil and water, and use of the copolymer a) with b) and /or c) in demulsifying crude oil and water forms a further aspect of the present invention.

The polymer a which is soluble or readily dispersible in toluene is new. It can be prepared in a manner known per se by copolymerizing the comonomers necessary for its formation in the presence of an initiator such as, for example, azodiisobutyronitrile. A process suitable for the preparation is described, for example, in German Patent Specification 3,338,923 an in British Patent Specification 2,129,819. The preparation of the compounds is furthermore shown in the examples.

The polyoxyalkylene ethers of the formula I can be prepared by addition of ethylene oxide, propylene oxide, butylene oxide or o-olefin oxide of long-chain hydrocarbons containing up to 30 carbon atoms to allyl or methallyl alcohol. Particularly effective demulsifiers are obtained on using mixtures of various polyoxyalkylene ethers of allyl and/or methallyl alcohol for the preparation of the copolymers to be used according to the invention. In this connection, particularly preferred are mixtures of polyoxyethylene and polyoxypropylene ethers of allyl and/or methallyl alcohol. The ratio of the oxyalkylene units to each other should be chosen so that the copolymer obtained is soluble or readily dispersible in toluene.

As acrylic or methacrylic acid alkyl esters are chosen those whose alkyl group contains 1 to 20 carbon atoms Examples of such acrylic and/or methacrylic acid esters are: methyl acrylate, methyl methacrylate, butyl acrylate, butyl methacrylate, ethylhexyl acrylate, lauryl methacrylate or stearyl methacrylate. The copolymerization can be carried out in the presence of up to 20 mole % acrylic and/or methacrylic acid or up to 20 mole % acrylamide and/or methacrylamide, referred to acrylic and/or methacrylic acid alkyl ester.

Particularly favourable properties are obtained if the copolymerization is undertaken in the presence of allyl and/or methallyl ether monools which differ in relation to the number of allyl and/or methallyl ether groups n.

An essential feature of the copolymers to be used according to the invention consists in the matching of the mean molecular weight of the allyl and/or methallyl ether monools and the number of moles of the other compounds to be copolymerized. In this connection, the condition applies that the quotient of the mean molecular weight of the polyoxyalkylene ethers, corresponding to their molar proportion, and of the number of moles of the other compounds to be copolymerized is 20 to 150.

This may be explained in more detail by means of the following numerical example: if the copolymerization takes place using an allyl ether monool with a mean mole-cular weight of 2,000, the number of moles of the other compounds to be copolymerized may be 13.3 to 100: 2,000 = 20 or 2,000 = 150 100 13.3 If the copolymerization is performed with a mixture of various allyl ether monools, for example with 30 mole % of a polyether having a mean molecular weight of 1,800 and 70 mole % of a polyether having a mean molecular weight of 600, the numbers of moles of the other compounds to be copolymerized are 6.4 to 48:: (1,800 x 30 %) + (600 x 70 %) - 20 48 or (1,800 x 30 %) + (600 x 70 %) = 150 6.4 In the copolymerization of the abovementioned monomers, polymers are obtained whose molecular weight numbers are on average in a range from 5,000 to 25,000.

For the demulsifying of crude oil containing water the copolymers to be used according to the invention are generally employed in quantities of 5 to 200 ppm. For the purpose of improved metering, the copolymers are expediently dissolved in a solvent or mixture of solvents such as toluene, xylene or a mixture of aromatic solvents.

In this connection, the concentration of such stock solutions is in general 20 to 50% by weight.

When using the new copolymer a as demulsifier a rapid and quantitative separation of the water from the water-containing crude oil is effected. The aqueous and the oil phase separate under these conditions with the development of a relatively small intermediate phase, while in contrast thereto, on using the demulsifiers known from the prior art intermediate phases are in general developed which consist of oil/ water or water/oil emulsions of various concentrations. It is of advantage that the sediment components contained in the petroleum end up in the aqueous phase with the result that the oil phase is depleted of solid components originating from sediments.

The properties and in particular the universal applicability of the demulsifiers to be used according to the invention can be increased still further by using the copolymers a together with other demulsifiers of the prior art known per se.

Particularly favourable effects are obtained if the copolymers a to be used according to the invention are used together with certain alkylene oxide addition products to alkyl phenol formaldehyde novolaks.

Novolaks of this type and their use as demulsifiers have been known for a long time. Of the extensive patent literature reference is made to the German Patent Specification 1,642,825, the US Patent Specifications 2,499,368, 2,409,370, 2,524,889, 2,560,333 and 2,574,543. The alkoxylated alkyl phenol formaldehyde novolaks selected within the frame-works of this invention contain as alkyl radicals straight or branched radicals containing 1 to 25 carbon atoms. As alkylene oxides, ethylene oxide and/or propylene oxide can be used. The nature and quantity of the alkylene oxide should, however, be selected so that the alkylene oxide addition product obtained is soluble in organic solvents such as, for example, toluene.

Particularly good demulsifying properties are to be found in demulsifying mixtures which, in addition to the component a and optionally the abovementioned alkoxylated novolaks to be used according to the invention, additionally contain the polymers known from German Patent Specification 3,338,923. These copolymers (component c) are obtainable by copolymerization of c1) one or more polyoxyalkylene ether(s) of allyl or methallyl alcohol of the general formula

n, RI, R2 defined as above, with c2) vinyl esters of alkyl monocarboxylic acids whose alkyl radical contains 1 to 4 carbon atoms, or mixtures thereof containing up to c21) 50 mole % acrylic or methacrylic acid alkyl esters whose alkyl radical contains 1 to 20 carbon atoms, c22) it being possible for up to 15 mole % of the alkyl radicals to be unsaturated, and the quotient of the mean molecular weight of the polyoxyalkylene ethers, corresponding to their molar proportion, and of the number of moles of the other monomers to be copolymerized being 20 to 100.

The index n and the groups Ri and R2 correspond in their definition to the index n or the groups Ri and R2 respectively of the formula I of the copolymer a. However, the individual meanings for the copolymers a and c in a mixture can be different. Thus, for example, the degree of alkoxylation expressed by the index n of the copolymer a may differ from the degree of alkoxylation of the copolymer c. The same applies to the groups R' and R2.

The weight ratio of the components a : b : c is 1 : 0 : 0 to 1: 4: 4.

In the following sections the preparations of the components a, b and c of the demulsifiers to be used according to the invention is described.

Component a: 1. Preparation of an allyl polyetherol (1)116 g (approx. 2 moles) of allyl alcohol and 21 g (approx. 0.3 mole) of potassium methylate are introduced into a reactor. After carefully flushing with pure nitrogen, the temperature is raised to 110"C and 1,302 g (approx 29.6 moles) of ethylene oxide are added so rapidly that the internai reactor temperature does not exceed 1200C and the pressure does not exceed 6 bar.

After complete introduction of the ethylene oxide the temperature is held at 11 50C until a constant pressure indicates the end of the post-reaction. Thereafter the residual monomers are removed at 80 to 90"C in vacuo.

The product obtained is neutralized by means of phosphoric acid, the water is removed by distillation, and the sodium phosphate produced is removed by filtration using a filter aid. The hydroxyl number of the product of the process is 94.3, which, assuming a functionality of 1, corresponds to a molecular weight of 595. A content of 89 mole % double bonds can be calculated from the iodine number.

2. Copolymerization of the allyl polyetherol I with n-butyl acrylate and with methacryiates having longchain alkyl groups.

990 g (approx. 2 moles) of the allyl polyetherol I obtained are heated to 800C in a three-neck flask under a stream of nitrogen. To the latter 15.6 g of azodiisobutyronitrile is added. Then, distributed uniformly over a period of 2 hours, 1,536 g (approx. 12 moles) of n-butyl acrylate, 332 g (approx. 1 mole) of stearyl methacrylate and 254 g (approx. 1 mole) of lauryl methacrylate are added dropwise. Thereafter, distributed three times over 2 hours, 15.6 g of azodiisobutyronitrile are added in each case. The temperature is left at 80"C. Finally, a post-reaction takes place for a further 2 hours at this temperature. The n-butyi acrylate still remaining is distilled off in vacuo. From the quantity of monomers collected in a cold trap a polymerization yield, referred to n-butyl acrylate, of 99% of theory results.From the determination of the iodine number it can be concluded that approx. 66.7% of the allyl polyetherol I are consumed in the copolymerization. From the gel permeation chromatography investigation a numerical molecular weight of approx. 7,700 results. The viscosity of the product is 34,000 mPas; it is soluble in solvents such as benzine, toluene without phase separation.

The polymer is denoted as al.

For the preparation of the products a2 to a15 further polyols are prepared in accordance with the specification al. The composition of the allyl polyetherols emerges from Table 1. The molecular weight of the allyl polyetherols is determined from the OH number.

TABLE 1 Allyl Ethylene Propylene Molecular polyetherol oxide oxide weight (Mole) (Mole) (OH No.) II 6.1 - 305 lil 14.4 - 632 IV 11.6 20.7 1710 In the case of allyl polyetherol IV the total quantity of propy!ene oxide is first added, then the total quantity of ethylene oxide is added, so that a block-type structure is achieved.

Table 2 specifies which allyl polyetherols, which monomers and in each case what quantities there-of are used for the preparation of the products a2 to a15.

TABLE 2 Product Polyether No. (mole) Methyl n-Butyl Ethyl- Acrylic Acryl- Lauryl Stearyl Quotient acrylate acrylate hexyl acid amide meth- methacrylate acrylate acrylate II III IV (mole) (mole) (mole) (mole) (mole) (mole) Q (mole) a2 1 1 0.5 6 - - - - 1 1 90 a3 1 1 0.5 12 - - - - 1 1 51 a4 1 1 0.5 - 6 - - - 1 1 90 a5 1 1 0.5 - 12 - - - 1 1 51 a6 1 1 0.5 - 20 - - - 1 1 33 a7 1 1 0.5 - - 6 - - 1 1 90 a8 1 1 0.5 - - 12 - - 1 1 51 a9 1 1 0.5 12 - - 1 - 1 1 48 a10 1 1 0.5 - 12 - 3 - 1 1 42 a11 1 1 0.5 12 - - - 1 1 1 51 a12 1 1 0.5 - 12 - - 2 1 1 45 a13 1 1 0.5 - 12 - 1 - 1 1 48 a14 - 2 - - 12 - - - 1 1 51 a15 1 1 0.5 - 12 - - - 1 1 51 Component b: Preparation of the alkoxylated alkyl phenol formaldehyde novolak.

440 g (approx. 2 moles) of p-nonylphenol are first heated to a temperature of 85"C together with 72 g (approx. 0.8 mole) of trioxane (~ 2.4 moles of formaldehyde), 8 g of p-dodecylbenzenesulphonic acid and 260 9 of toluene in a three-neck flask which is provided with a reflux condenser and a water separator.

After the start of the reaction the temperature is gradually raised to 95"C, during which process the water of reaction is removed azeotropically with toluene. After the elapse of one hour the trioxane used is completely dissolved and the water of reaction is largely removed. After 2 hours of potassium the temperature is reduced to 80 ot 85"C and approx. 10 g (approx. 0.18 mole) of solid powdered potassium hydroxide are added. Thereupon heating is again carried out until the water separates azeotropically.

After 2 hours of postreaction cooling down is finally carried out.

The nonylphenol resin obtained is transferred to a reactor and, after carefully flushing with pure nitrogen, is heated therein to 110 C. A total 0.67-fold quantity of ethylene oxide is then added at a rate at which the internal reactor temperature does not exceed 1200C and the pressure does not exceed 6 bar.

After complete introduction of the ethylene oxide the temperature is held at 115"C until a constant pressure indicates the end of the post-reaction; thereafter the residual monomers are removed at 80 to 90"C in vacuo.

The product obtained is neutralized by means of phosphoric acid, the water is removed by distillation and the sodium phosphate produced is removed by filtration using a filter aid.

The product is designated as b.

Component c: The preparation of the allyl polyetherols takes place as described for the component a in section 1. The preparation of the copolymers c1 to c10 takes place as described for the component a in section 2. Table 3 corresponds to table 2 in the case of component c.

TABLE 3 Product Polyether No. (mole) Vinyl Methyl n-Butyl Ethyl- Acrylic Acryl Lauryl Stearyl Quotient acetate acrylate acrylate hexyl acid amide meth- methacrylate acrylate acrylate II III IV (mole) (mole) (mole) (mole) (mole) (mole) (mole) (mole) Q C1 1 1 0.5 12 - - - - - 1 1 51 C2 1 1 0.5 6 6 - - - - 1 1 51 C3 1 1 0.5 6 6 - - - - 1 1 51 C4 1 1 0.5 6 6 - - - - 1 1 51 C5 1 1 0.5 6 6 - - - 1 1 1 48 C6 1 1 0.5 6 - 6 - - - 1 1 51 C7 1 1 0.5 6 - 4 - - - 1 1 51 C8 1 1 0.5 6 - 6 - 1 - 1 1 48 C9 1 1 0.5 6 - 6 - - 1 1 1 48 C10 1 1 0.5 - - 6 6 - - 1 1 51 The products alto a15, b and c1 to c10 are dissolved in toluene, alone or mixed in selected combinations and quantity ratios. Only the mixtures 21 and 24 are dissolved in a mixture consisting of 80 parts by weight of methanol and 20 parts by weight of water. The concentration is 5.7% by weight.

In table 4 the composition of the agents to be used according to the invention is specified.

TABLE 4 Demulsi- Products (parts by weight) fier prepara tion al a3 a5 a8 alO a12 al3 al5 b c7 c2 c3 c5 1 -1----------- 2 - - 1 - - - - - - - - - 3 - - - 1 - - - - - - - - 4 - - - - 1 - - - - - - - - 5 - - - - - 1 - - - - - - 6 - - - - - - 1 - - - - - 7 1 - - - - - - - 1 - - - 8 - I - - 1 - - - 1 - - - - 9 --1 -----1 ---- 10 - - - 1 - - - - 1 - - - 11 - - - - 1 - - - 1 - - - 12 - - - - - - 1 - 1 - - - 13 - - - - - - - 1 1 - - - 14 - - - 2 - - - - 1 - - - 15 - - - 4 - - - - 1 - - - - 16 - - - 1 - - - - 4 - - - 17 - - - 1 - - - - 1 - - 1 18 - - - 1 - - - - 2 - - 1 19 - - - 1 - - - - 1 - - 2 20 - - - 2 - - - 21 - - - - 1 - - - 1 - - 1 22 - - - - 1 - - - 2 - - 1 23 - - - - 1 - - - 1 - - 2 - 24 - - - - 2 - - - 1 - - 1 25 - - - - 2 - - - 1 - - 0.5 26 - - - - 0.5 - - - 1 - - 2 27 - - - - 1 - - - 1 1 - - 28 - - - - 1 - - - 1 - 1 - - 29 - - - - 1 - - - 1 - - - 1 30 1 - - - - - - - 1 1 - - Applications test of the preparations to be used according to the invention.

The preparations 1 to 30 to be used according to the invention are tested on petroleums of various origin.

The performance of the applications test takes place in the so-called "bottle test" described in "Treating Oil Field Emulsion", edited by Americal Petroleum Institute, Dallas, Texas, 1974, page 33 et seq. In tables 5 to 7 the quantities of water separated after certain times are specified in % by volume; the determination is carried out in accordance with ASTM D 96-68 (API 2542). In addition, the temperature at which the demulsification takes place, the 50% solution used in each case, the demulsifier, the absolute water content and the residual water content are specified.

The demulsifiers A and B are products of the prior art and serve as a comparison. In this connection, demulsifier A is a block copolymer consisting of about 70% by weight of propylene oxide and about 30% by weight of ethylene oxide with a mean molecular weight of about 3000. The demulsifier B is an ethoxylated phenol formaldehyde condensation product of the novolak type available commerically under the designation Dissolvan 4490 and described in German Patent Specification 1,642,825.

The results of the demulsification of crude oil from Venezuela with a mean water content of 40 to 44% by volume are shown in table 5. 100 ppm of demulsifier (active suostance) are useo in each case. The sample size is 100 ml, and the temperature during the separation 80"C.

The results of the demulsifying of crude oil from the North Sea which has a mean water content of 18% by volume are shown in table 6. The quantity of demulsifier added is 20 ppm, the temperature during the separation is 25"C.

The results of demulsifying crude oil from North Germany with a mean water content of 32% by vol ume are shown in table 7. 50 ppm of demulsifier are used in each case. The temperature during the separation is 40 C.

TABLE 5 Demulsifier ml of water Residual Emulsion comp.

preparation separated after [min] water of in term. phase No. 3 6 24 [%] 1 17 34 41 1.0 0.9 2 19 36 44 < 0.5 0.1 3 16 28 41 1.0 1.1 4 21 39 44 0.5 0 5 22 40 44 0.5 0.2 6 15 32 40 1.0 2.3 7 12 24 38 1.5 2.0 8 18 25 39 2.0 2.2 9 12 22 39 1.5 2.0 10 10 20 35 2.0 2.0 11 12 30 42 0.5 1.0 12 15 31 40 1.0 1.5 13 12 27 39 1.0 1.5 14 10 25 40 1.0 1.5 15 13 28 35 2.5 2.0 16 19 29 40 1.0 2.2 17 15 35 45 0.5 0.5 18 16 30 43 0.5 0.8 19 10 25 40 1.0 0 20 10 28 40 1.0 0.8 21 10 29 44 0.5 0.5 22 18 25 42 1.0 0.8 23 10 19 44 0.5 0.2 24 17 25 42 0.5 0.8 25 12 19 39 1.5 1.0 26 11 20 38 1.5 0 27 15 27 41 1.0 0.5 28 14 23 38 2.0 1.0 29 12 23 39 2.5 1.0 30 13 25 40 1.0 0.5 Demulsifier A 15 22 37 2 3.2 Demulsifier B 18 25 36 3 2.5 TABLE 6 Demulsifier ml of water Residual Emulsion comp.

preparation separated after [min] water of in term. phase No. 1 5 10 [%] zoo 1 1 10 15 2 0.9 2 3 12 18 < 0.5 0.5 3 2 10 16 3 1.0 4 3 12 17 1 0.8 5 2 15 18 < 0.8 0.5 6 Tr. 8 13 3 2.0 7 1 8 12 5 4.0 8 1 9 14 3 2.5 9 2 9 15 2 2.0 10 1 7 14 3 3.5 11 2 8 11 5 4.5 12 3 9 15 3 4.0 13 3 12 18 0.5 0.8 14 2 11 16 1 1.5 15 1 12 17 1 1.5 16 3 10 15 2 2.5 17 3 12 17 0.5 0.5 18 2 10 17 0.5 0.3 19 2 9 13 4 0 20 3 10 15 2 0.5 21 2 11 16 1 0.5 22 2 10 16 1.5 1.0 23 1 11 15 2 Tr.

24 2 13 15 2 1.5 25 3 13 18 < 0.5 Tr.

26 2 12 16 1.0 0 27 2 11 16 1 0.3 28 3 11 17 1 0.5 29 3 10 17 < 0.5 Tr.

30 1 11 15 2 0.5 Demulsifier A 1 5 14 6 2.5 Demulsifier B Tr. 8 12 4 3.0 Tr = traces TABLE 7 Demulsifer ml of water Residual Emulsion comp.

preparation separated after [mini water of interm. phase No. 0.5 1 3 [ /O] [ /Ol 1 18 28 31 0.5 0.5 2 24 30 32 < 0.5 Tr.

3 16 25 28 1.0 1.3 4 22 30 31 < 0.5 Tr.

5 21 31 32 < 0.5 0 6 15 24 29 1.0 1.1 7 10 21 28 1 1.2 8 13 20 26 1.5 2.0 9 15 20 27 1 1.0 10 14 22 29 '1 1.0 11 20 24 28 1 1.8 12 22 24 27 1 1.3 13 24 27 30 < 0.5 Tr.

14 23 28 30 < 0.5 Tr.

15 21 27 30 < 0.5 Tr.

16 20 24 30 < 0.5 Tr.

17 26 30 32 < 0.5 Tr.

18 27 29 32 < 0.5 tr.

19 24 29 31 < 0.5 0 20 23 28 30 0.5 0.5 21 20 25 28 1 0.5 22 22 24 28 1 0.7 23 24 26 29 0.5 Tr.

24 19 25 27 1 0.5 25 19 22 29 0.5 0.4 26 20 24 30 < 0.5 0 27 26 29 32 < 0.5 Tr.

28 25 3.0 31 < 0.5 Tr.

29 18 22 27 1 0.5 30 19 23 29 0.5 Tr.

Demulsifier A 10 21 25 6 3.5 Demulsifier B 7 16 22 7 2.0 Tr. = traces A comparison of the values in the tables shows that the demulsifiers to be used according to the invention have very good demulsifying properties, the content of residual water, in particular, being very low and the emulsion component being very low.

Claims (13)

1. A copolymer which is soluble or readily dispersible in toluene and is obtained by copolymerization of a1) one or more polyoxyalkylene ether of allyl or methallyl alcohol of the general formula

in which n is an integer 3 2, RI is allyl or methallyl, R2 is hydrogen or optionally halogenated hydrocarbon containing 1 to 30 carbon atoms, with a2) an acrylic and/or methacrylic acid alkyl ester containing 1 to 20 carbon atoms in the alkyl group or mixtures thereof with a2,) up to 20 mole % acrylic and/or methacrylic acid or a22) up to 20 mole % acrylamide and/or methacrylamide, and the quotient of the mean molecular weight of the polyoxyalkylene ether, corresponding to their molar proportion, and of the number of moles of the other monomers to be copolymerized being 20 to 150.

2. A copolymer as claimed in claim 1 in which the copolymerization to produce the copolymer is undertaken in the presence of allyl and/or methallyl ether monools which differe in relation to the number of allyl and/or methallyl ether groups.

3. A copolymer as claimed in any one of the preceding claims which has an average molecular weight of 5,000 to 25,000.

4. A copolymer as claimed in any one of the preceding claims in which the polyoxyaikylene ether al) is the addition product of ethylene oxide, propylene oxide, butylene oxide or a-olefin oxide of a C1-C30 hydrocarbon with ally or methallyl alcohol.

5. A copolymer as claimed in claim 1 substantially as described herein with reference to any of Examples alto a15.

6. A mixture of the copolymer as claimed in any one of the preceding claims with b) a toluene-soluble alkylene oxide addition product of an alkyl phenol formaldehyde novolak, the alkyl group being straight-chain or branched and containing 1 to 25 carbon atoms and/or c) a copolymer which is obtainable by copolymerization of cl) one or more polyoxyalkylene ether of allyl or methallyl alcohol of the general formula

in which n, Ri, R2 are defined as above, with c2) vinyl esters of alkyl monocarboxylic acids whose alkyl group contains 1 to 4 carbon atoms, or mixtures thereof containing up to c2,) 50 mole % acrylic or methacrylic acid alkyl esters whose alkyl radical contains 1 to 20 carbon atoms, c22) it being possible for up to 15 mole % of the alkyl radicals to be unsaturated, and the quotient of the mean molecular weight of the polyoxyalkylene ethers, corresponding to their molar proportion, and of the number of moles of the other monomers to be copolymerized being 20 to 100, the weight ratio of the components a : b : c being from 1 : 0 : 0 to 1 :4: 4.

7. A copolymer as claimed in claim 1 or mixture as claimed in claim 6 substantially as hereinbefore described with reference to any of preparations 1 to 30.

8. Use of copolymer or mixture as claimed in any one of the preceding claims in demulsifying crude oil and water.

9. Use according to claim 8 in which the copolymer or mixture is present as demulsifer in an amount of 5 to 200 ppm.

10. Use according to claim 8 or 9 in which the copolymer or mixture is dissolved in a solvent.

11. Use according to claim 10 in which the solvent is toluene, xylene or a mixture of aromatic solvents.

12. Use as defined in claim 8 of a copolymer or mixture substantially as described in any of Examples alto a15 and Preparations 1 to 30.

13. Use as defined in claim 8 and substantially as described in any of the Application tests of a copolymer or mixture.