GB2125414A - De-emulsifiers for petroleum/water emulsions - Google Patents

Abstract

Organosilicon-modified polydienes of formula (I> <IMAGE> wherein Z denotes a chain-terminating group, are de-emulsifiners for petroleum/water emulsions and are prepared by addition of silanes of formula (CH3)aSiHX3-a onto polydienes followed by reaction with alcohols and polyethers.

Description

SPECIFICATION The use of organosilicon-modified polydienes as de-emulsifiers for petroleum/water emulsions The present invention relates to a process for the de-emulsification of petroleum/water emulsions, to compounds for use in such a process and to the preparation of such compounds.

On lifting, a substantial proportion of crude petroleum contains more or less salt water in emulsified form. Such emulsions, which are chiefly in the form of water/oil emulsions, need to be separated into their phases, since the salt present in the emulsion would interfere with the further processing of the petroleum, in particular during transport and in the distillation.

Such crude petroleum emulsions are separated into their phases by leaving the emulsion to settle, thermal treatments, centrifuging, by applying electric fields or by adding de-emulsifiers, or by a combination of several of these methods.

The lifted crude petroleum emulsions are usually too stable to be broken solely by sedimentation, filtration, centrifugation or heating, while de-emulsifiers are successful in breaking the emulsions even in low concentrations, in some cases.

A large number of de-emulsifiers have already been proposed, not least because the various petroleums differ in composition and de-emulsifiers which are suitable for breaking emulsions of petroleums from one origin are unsuitable for petroleum emulsions from other production sites. For this reason, known de-emulsifiers have a more or less specific action on individual crude oils.

De-emulsifiers already proposed include alkyl sulphates and alkyl arenesulphonates as well as petroleumsulphonates in the form of amine salts. Adducts of ethylene oxide on suitable compounds having an active hydrogen atom, such as, for example, alkyl phenols, castor oil, fatty acids, fatty alcohol, alkyl phenol or aldehyde resins, have also been mentioned. Relevant information can be found, for example, in the book "Oberfl chenaktive Anlagerungsprodukte des Ethylenoxids" [Surface-active ethylene oxide adducts], by N. Schönfeld, published by Wissenschaftliche Verlagsgesellschaft mbH, Stuttgart, 1959, page 295.

German Patent 1,937,130 states that certain known polyoxyalkylene/polysiloxane block copolymers have excellent properties as de-emulsifiers for petroleum emulsions of the water/oil type from a wide variety of sources and, what is more, have a de-emulsifying action in very low amounts, i.e.

in lower amounts than prior art products. The polyoxyalkylene/polysiloxane block copolymers have polyoxyalkylene blocks with a molecular weight of 500 to 4,000 which consist of polyoxyethylene and polyoxypropylene blocks in a weight ratio of 40:60 to 100:0. The polysiloxane blocks have 3 to 50 silicon atoms per block.

German Patent 2,250,920 concerns mixtures of 0.2 to 30% by weight of the abovementioned polyoxyalkylene/polysiloxane block copolymers with 70 to 99.8% by weight of silicon-free deemulsifiers which consist of alkylene oxide adducts on organic compounds which contain reactive hydrogen atoms, suitable being in the main: reaction products of alkylene oxides with alkylphenolaldehyde resins: block polymers and copolymers of propylene oxide and ethylene oxide; their reaction products with dicarboxylic acids or diisocyanates and mixtures of these products. It was found that the mixtures of German Patent 2,250,920 have particularly favourable properties in respect of deemulsification combined with foam prevention.

German Patent 2,321,557 discloses silicon-containing block copolymers based on organosiliconmodified polydienes. These compounds are obtained by addition of hydrogen-containing silanes onto polydienes, the silanes also having halogen, alkoxy or acyloxy radicals which are then reacted with polyethers. These compounds can be used for many purposes. They are additives in the preparation of polyurethane foams; they are useful mould-release agents; and they can be used as finishes in the textile industry or be used on cosmetics. Another application mentioned is the use of these compounds as de-emulsifiers for separating petroleum/water emulsions into their phases.

The present invention provides a process for the de-emulsification of a petroleum/water emulsion, which process comprises adding to the emulsion an organosilicon-modified polydiene of the general formula (I) wherein

Z denotes a chain-terminating group, each R', which may be identical or different, denotes a hydrogen or methyl radical, each R2, which may be identical or different, denotes an alkyl or alkylaryl radical having 6 to 24 carbon atoms in which the alkyl radical or the alkyl group of the alkylaryl radical may optionally be fluorinated, each R3, which may be identical or different, denotes the radical (R40--),Y, where each R4, which may be identical or different, comprises an alkylene radical having 2 to 4 carbon atoms, m > 2 and Y is an alkyl radical having 1 to 4 carbon atoms, and where on average w > O, x > 0 Y 3, a=0to2, b = O or 1, 0 < c < 3 where 0 < a + c < 3.

It has been found that the compounds of formula (I) are particularly suitable for use as deemulsifiers, in particular for separating petroleum/water emulsions into their phases, in that they can very rapidly and completely separate off the water present in lifted petroleum. These compounds can exhibit de-emulsifying properties for various crude oils and may therefore be as universally applicable as possible. The compounds of formula (I) are also compatible and miscible with prior art de-emulsifiers, so that this is another way in which their application spectrum becomes as broad as possible. A particular characteristic of the compounds of the invention is the Si-O-C-linked long-chain alkyl or alkylaryl groups, which evidently contribute to an increased interaction with the oil phase in petroleum emulsions.

The invention also provides the compounds of formula (I).

In the formula, Z denotes chain-terminating groups which are determined by the method of preparation chosen for the polydiene. Examples of such groups are -H, CH2=CH-CH2-CH2-, -CH2-CH2-0H, -COOH, -CH3,-C4H#, -C6H5,-CH2-C6H5, and -Si(CH3)3.

R1 can be identical or different within one and the same polymeric molecule and can denote a hydrogen or methyl radical.

R2 can also be identical or different within one and the same polymeric molecule, and is an alkyl or alkylaryl radical which has 6 to 24 carbon atoms, preferably 8 to 24 carbon atoms, in particular 12 to 24 carbon atoms, and the alkyl group should be branched. Branched alkyl groups with a relatively high carbon content have the advantage that the viscosity of the modifiers is reduced. The alkyl radicals can also be fluorinated, in particular partially fluorinated. Examples of such fluorinated radicals are CF3-(CF2-)6CH2-, CF3-(CF2-)5CH2-CH2-, and CF3-(CF2-)7CH2-CH2-.

R3 can be identical or different within one and the same polymeric molecule, and denotes a polyether radical of the formula (R40~)mYs R4 is an alkylene radical having 2, 3 or 4 carbon atoms. R4, too, can be identical or different within the average molecule. Those polyethers are preferred which have polyethylene oxide and/or polypropylene oxide units, where, in the case of copolymers, these units can appear as random mixtures or in separate blocks. Products which have a secondary OH group are preferred. The oxyalkylene blocks can thus be made up of oxyethylene, oxypropylene and/or oxybutylene units. The oxyalkylene radical preferably consists of at least 40% by weight of oxyethylene units. m is < 2. m preferably has such a value that the molecular weight of the radical R3 is 300 to 6,000. Y is an alkyl radical which has 1 to 4 carbon atoms. It is particularly preferably a methyl or a butyl radical.

The numerical values for the indices w, x, y, a, b and c relate to the average molecule. This means that they can have different values within the polymeric mixture. On average, however, they must satisfy the stated conditions.

Those compounds are preferably used in which the unsubstituted units which have double bonds and are designated with the indices w and x are present in an amount of 25 to 80 mol % of the total of the units w + x + y.

Those compounds are used particularly preferably in which the index b is on average 1 and R2 is derived from a primary alcohol or phenol.

Examples of compounds for use in the invention are:

C : 0 ratio of radical R4 = 2.2 1

C : 0 ratio of radical R4 = 2.5 1

C: O ratio of radical R4 = 2.2 :1

C: 0 ratio of radical R4* = 2.2 1 C: 0 ratio of radical R4** = 2.5 1 The formula I compounds for use in the invention can be prepared by addition of at least y mols of silanes of the general formula (CH3)aSiHX3-a VI where X ia a halogen, alkoxy or acyloxy radical, in a known manner onto polydienes of the general formula

which have a molecular weight of 300 to 200,000, in the presence of noble metal catalysts and reacting the resulting adducts with at least y (3-a-c) mols of compounds of the general formula CH3 R20~(CH2~CH~O~XbH VIII andy-c mols of compounds of the general formula R30H IX The radicals R', R2, R3 and Z and the indices a, b, c, w, x, and y have the already given meanings.

German Patent 2,321,557 describes an analogous way of carrying out such a method. The catalysts used for the addition of silanes of the formula Vl onto polydienes of the formula VII are in particular platinum catalysts, such as, for example, hexachloroplatinic acid or platinum ethylenepyridine dichloride. The reaction is advantageously carried out in the presence of a solvent, in particular toluene.

The addition of silane onto polydiene is preferably carried out at elevated temperatures, for example at the boiling point of toluene.

The reaction of the resulting intermediates with the compounds of the formula CH3 R20~(CH2~CH~O~)bH Vlil and with compounds of the formula R30H IX is advantageously also carried out in the presence of a solvent, toluene being again preferred. However, it is also possible to use other inert solvents, such as, for example, methylene chloride, glycol ethers or cyclic ethers. If X denotes a halogen radical, the hydrogen halide liberated is advantageously bound with ammonia. The ammonia can also be replaced by an amine. The carboxylic acid liberated when X denotes an acyloxy radical can be neutralised in a similar manner. If X denotes an alkoxy radical, it is advisable to remove from the reaction mixture the low molecular weight alkanol liberated by distillation.

For this reason it is also preferable that the alkoxy radical used should be a methoxy or ethoxy radical.

The de-emulsifiers of the invention are preferably added to the petroleum/water emulsions in amounts of 1 to 300 ppm. It is also possible to dissolve the de-emulsifiers in a solvent, such as, for example, toluene, and to add the solution to the petroleum. These compounds cause rapid and substantially complete separation of water from the crude oil. The compounds do not interfere with the further treatment of the oil and, in particular, do not cause foaming in the distillation or working-up of the oil.

The Examples, which follow, illustrate the present invention.

EXAMPLE 1 General method of preparation The reaction vessel is charged at the boiling point of toluene with an approximately 50% strength toluene solution of the polydiene which contains as catalyst 15 mg of platinum ethylenepyridine dichloride per mol of SiH, and the desired amount of hydrogensilane is added dropwise. On completion of the reaction the acid value of the product is measured, and the appropriate amount of alcohol/polyether mixture is added together with molar amounts of triethylamine. The reaction mixture is filtered and the toluene distilled off to give the desired end product, which, if desired, can be stabilised by additives.

EXAMPLE 2 Demulsification trials Two different North German crude oils were used, oil A containing 48% of water and oil B 28% of water. 20 ppm of various substances were added in each case to 50 ml of crude oil in a calibrated inspection glass, and the amount of water separated off after certain times was noted in ml. Throughout the entire trial the temperature was kept at a constant value of 50 C. The substances tested were polyethers having various EO/PC ratios, their reaction products with polydiene/hydrogensilane adducts and products of the invention which additionally contained long-chain alcohol derivatives.

Example 1 of German Patent 1,642,825 and of German Patent 2,321,557 were repeated to provide a comparison with the state of the art.

In the table below, which shows the experimental results, the following substances are labelled with numbers from 1 to 13.

1 polyether C4H9O(CnH2nO)36.9H n = 2 and 3, C : 0 = 2.2 1 2 polyether C4H9O(CnH2nO)33.8H n=2;3and4,C :0=2.5:1

6 formula I where w = 5, x = 25, Y = 30, R1 = H, R2 = isooctadecyl-, a =1, b = 1, C =O 7 as 6, where a = 1, c = 2, R3 = C4H9(OCnH2n)36.9 n = 2 and 3, 0 : 0 = 2.2 :1 8 as 7, where R3 = C4H9(OCnH2n)33.8 n = 2; 3 and 4, C :O = 2.5:1 9 as 6, where R2 = isotridecyl-, R3 = C4H9(OCnH2n)33.8@ a= 1,b=1,c= 1, n = 2 and 3, C : 0 = 2.5 :1 10 as 9, where R2 = isooctadecyl-, R3 = C4H9(OCnH2n)36.9' n=2 and 3,C:0=2.2:1 11 as 10, where R2 = nonylphenyl 12 product of example 1 in Germany Patent 1,642,825 13 product of example 1 in German Patent 2,321,557 The comparison between substances 9 to 11, of the invention, are substances not of the invention demonstrate that only the presence of polyethers and long-chain alcohols in molecules of the formula I ensure a very good effect in the de-emulsification of petroleum/water emulsions.

The comparison with the state of the art de-emulsifiers (substances 12 and 13) shows the superiority of the compounds of the invention.

Water separated off (ml) after

0.5h 1h 2h 3h A B A B A B A B De#rr.uIsifier 1 0 0 1 0 1 1 2 1 not of the invention De-emulsifier 2 0 0 0 0 2 1 3 2 De-emulsifier3 0 0 0 O 0 0 0 0 De-emulsifier 4 0 0 0 0 0 0 0 0 Deemulsifier 5 0 0 0 0 0 0 0 0 De-emulsifier 6 0 0 0 0 0 0 0 0 De-emulsifier 7 2 1 2 1 8 9 10 10 Deernulsifier 8 0 0 5 2 8 9 12 9 De-emulsifier 9 10 5 18 9 22 12 23 12 of the invention De-emulsifier 10 18 7 19 12 21 12 21 14 De-emulsifier 11 12 7 18 10 21 11 22 14 De-emulsifier 12 1 8 5 12 6 16 8 18 10 comparison with state of the art De-emulsifier 13 9 1 13 3 15 8 15 9

Claims (18)

1. A process for the de-emulsification of a petroleum/water emulsion, which process comprises adding to the emulsion an organosilicon-modified polydiene of the general formula (I)

wherein each Z independently denotes a chain-terminating group, each R', which may be identical or different, denotes a hydrogen or methyl radical, each R2, which may be identical or different, denotes an alkyl or alkylaryl radical having 6 to 24 carbon atoms in which the alkyl radical or the alkyl group of the alkylaryl radical may optionally be fluorinated, each R3, which may be identical or different, denotes the radical (R4O--)mY, where each R4, which may be identical or different, comprises an alkylene radical having 2 to 4 carbon atoms, m > 2 and Y is an alkyl radical having 1 to 4 carbon atoms, and where on average w > 0 x#0, Y#3, a = 0 to 2, b=0 or 1, 0 < c < 3 where 0 < a + c < 3.

2. A process according to claim 1 wherein Z is selected from -H, OH 2=CH-CH2-CH2-, --CH2-CH 20H, -C00H, -CH3,-C4H8,-C6H8,-CH 2-C8H8 and -Si(CH3)3.

3. A process according to claim 1 or 2 wherein R2 has from 12 to 24 carbon atoms.

4, A process according to any one of the preceding claims wherein R2 is a branched alkyl radical or a (branched aikyl)aryl radical.

5. A process according to any one of the preceding claims wherein m is chosen such that the molecular weight of the radical R3 is from 300 to 6000.

6. A process according to any one of the preceding claims wherein at least 40% by weight of oxyalkylene radicals (R40-) in R3 consists of oxyethylene units.

7. A process according to any one of the preceding claims wherein Y represents methyl or butyl.

8. A process according to any one of the preceding claims wherein from 25 to 80 mol% of the total molecular weight of the units designated by the indices x, x and y consists of the units designated by the indices w and x.

9. A process according to any one of the preceding claims wherein b is on average 1 or R2 is derived from a primary alcohol or phenol.

10. A process according to claim 1 wherein the compound of formula (I) is any one of compounds nos. (II) to (V) hereinbefore specified.

11. A process according to any one of the preceding claims wherein the compound of formula (I) is added to the petroleum/water emulsion in an amount of from 1 to 300 ppm.

12. A process for the de-emulsification of a petroleum/water emulsion, said process being substantially hereinbefore described with reference to Demulsifier 9, 1 0 or 11.

13. An organosilicon-modified polydiene of the general formula (I) as defined in any one of claims 1 to 9.

14. Any one of compounds nos. (II) to (V) or any one of demulsifiers 9 to 11 hereinbefore specified.

15. A process for the preparation of a compound of general formula (I) as defined in claim 1, which process comprises (i) effecting an addition reaction between a polydiene of general formula (VIII), having a molecular weight of from 300 to 200,000,

wherein Z, R1 w, x and y are as defined in claim 1, and at least y moles of silane of general formula (VI): (CH3)aSiHX3-a (vl) where X represents halogen, alkoxy or acyloxy and a and y are as defined in claim 1, per mole of the polydiene of formula (VIII), in the presence of a noble metal catalyst therefor; and (ii) reacting the resulting adduct with at least y(3-a-c) moles of compound of general formula (VIII):

where R2, b and c are as defined in claim 1, and y-c moles of compound of general formula (IX): R30H (IX) where R3 is as defined in claim 1.

16. A process according to claim 15 wherein the noble metal catalyst is a platinum catalyst.

17. A process according to claim 15 or 16 wherein one or both of steps (i) and (ii) are effected in the presence of a solvent.

18. A process according to claim 15 substantially as hereinbefore described in the "General method of preparation".