EP0359061B1 - Aqueous emulsion copolymerisates, especially dilutable in water and oil, for modifying the flow properties and pour point reduction of petroleum and petroleum fractions, and their use - Google Patents

Abstract

Aqueous emulsion copolymerizates of (meth)acrylates of long-chain alcohols in closed aqueous phase contain the following monomer components as disperse-phase copolymerizates with long storage life: at least 50 wt.%, preferably at least 60 wt.%, or (meth)acrylates of C16-30 alcohols; 0 to 25 wt.%, preferably 5 to 10 wt.%, of (meth)acrylates of alcohols with not more than 8 carbon atoms; and 0.5 to 40 wt.%, preferably approximately 1 to 25 wt.%, of olefinically unsaturated mono- and/or dicarboxylic acids or their anhydrides with a total of up to 10 carbon atoms. Also described is the use of these aqueous emulsion copolymerizates to reduce the pour point or flow point of hydrocarbon mixtures, in particular crude oil or crude oil fractions, in which the above-mentioned copolymerizates can be incorporated into hydrocarbon mixtures of the above-mentioned type in the form of a highly-concentrated but very mobile disperse phase of aqueous emulsion copolymerizates.

Description

It is known to improve the flow properties of crude oils and / or petroleum fractions by using limited amounts of synthetic flow aids. As is known, the task of these flow aids is to lower the respective temperature below the solid constituents in the liquid hydrocarbon mixture - in particular higher paraffins and / or asphaltenes - in such amounts that the flowability of the hydrocarbon mixtures is permanently impaired. The temperature range mentioned here is determined by the known methods of determining the pour point or pour point. Due to its specific composition, each crude oil and the petroleum fractions obtained from it have their own pour point, which is generally below about 20 ° C for the oil deposits that are considered worthy of production today and shows values in the range of about 10 to 18 ° C, for example. In practice, the use of flow aids based on different synthetic homopolymer and / or copolymer types can be advisable.

There is extensive prior art on such auxiliaries, which are also referred to as crystallization inhibitors and generally by polymerization of olefinically unsaturated compounds, the at least partially unbranched saturated hydrocarbon chains with at least 18 carbon atoms included, manufactured. Reference is made, for example, to DE-AS 22 10 431 and DE-OSs 26 12 757, 22 64 328, 20 62 023, 23 30 232, 19 42 504 and 20 47 448.

In practice, particular difficulties arise when the intrinsic pour point of the crude oil or the petroleum fraction to be processed reaches extremely high values, which in particular can be at least 25 ° C and can be 30 ° C and above. Petroleum materials of this type tend to solidify rapidly even at ambient temperature. If, for example, pumping processes are interrupted even for a short time or if temperature ranges - for example through pipes in the seawater area - are crossed at relatively low temperatures, the rapid solidification of the hydrocarbon material results in a mass that is no longer pumpable and thus the blocking of pipes, pumps and the like. The situation is made more difficult by the fact that, in order to reliably rule out malfunctions of the type described, practice is often required to lower the pour points of the oils or oil fractions to values below 15 ° C and in particular to values below 12 ° C or even below 10 ° C . It is immediately apparent that there are very special technological difficulties when, for example, it is necessary to lower the crude oil's own pour point from around 33 ° C to values well below 10 ° C. An additional difficulty to be taken into account here is that simply increasing the amount of any pour point improver generally does not lead to a correspondingly increased decrease in the pour point. Interactions between the flow aid and the solidifying constituents of the crude oil that have not been elucidated are probably responsible for the desired goal in the sense of a thres hold effect, whereby the specific constitution of the flow aid is of decisive importance for its effectiveness.

DE-PS 30 31 900 describes copolymers of n-alkyl acrylates with at least 16 carbon atoms in the alcohol residue and maleic anhydride with molar ratios of n-alkyl acrylate to maleic anhydride from 20: 1 to 1:10. Compounds of this type are said to be used as crystallization inhibitors for paraffin-containing crude oils. Examples shown numerically relate to the use of corresponding copolymers in the molar ratio of the acrylic acid ester to maleic anhydride in the range from 1: 1 to 8: 1. Crude oils with intrinsic pour points below 20 ° C. are predominantly used. A table of values deals with India crude oil, which is known to be a particularly paraffin-rich starting material (disruptive paraffin content 15%) and has an intrinsic pour point of 33 ° C. The optimum effectiveness of the copolymers used in this publication with regard to lowering the pour point on this starting material is 4: 1 in the molar ratio of acrylic acid ester / maleic anhydride. The lowest pour points set here are at 12 ° C.

The prior applications of the applicant DE 38 07 395 and DE 38 07 394 relate to the use of selected types of copolymer of the acrylic and / or methacrylic acid esters as flow improvers in paraffin-rich petroleum and petroleum fractions. The first application describes the use of copolymers of acrylic and / or methacrylic acid esters of higher alcohols or alcohol cuts with at least 16 carbon atoms in the alcohol residue and not more than 20% by weight, preferably about 0.5 to 15% by weight. % of free acrylic acid and / or methacrylic acid -% by weight based on copolymer weight - as an additive for crude oils and petroleum fractions containing paraffins and / or asphaltenes to lower their pour point or freeze point and improve the flow properties, especially in the temperature range just above the freeze point. The flow improvers in paraffin-rich oils or oil fractions with their own pour points are preferred 20 ° C, whereby a lowering of the pour points to values below 15 ° C and in particular below 10 ° C is possible.

The second of the aforementioned applications describes the use of copolymers of acrylic and / or methacrylic acid esters of higher alcohols or alcohol cuts with at least 16 carbon atoms in the alcohol residue and not more than 5% by weight, preferably 0.5 to 2.5% .-% maleic anhydride as a flow improver in paraffin-rich crude oils and / or petroleum fractions with their own pour points above 25 ° C to lower their pour points to values below 15 ° C, preferably below 10 ° C.

The use concentration of such flow improvers from the prior art cited and the applicant's older applications is known to be in the ppm range and is, for example, 20 to 1000 ppm, with amounts in the range from approximately 100 to 500 ppm being preferred. It is known that the homogeneous distribution of these extremely small amounts of additives is crucial for the effectiveness of the copolymers used. According to the technology used in practice, these pour point improvers are therefore used dissolved in suitable organic solvents, which enable the immediate molecular dispersion of the polymer molecules in the hydrocarbon fractions to be treated and their interaction with the components which are disruptive there, in particular higher paraffins and / or naphthenes. Details of suitable solvents can be found in the relevant prior art, for example in DE-PS 30 31 900 cited at the beginning.

The teaching of the invention described below is based on a particular difficulty, the acrylate or methacrylate copolymers - hereinafter referred to as (meth) acrylate copolymers - when they are used in oil-soluble solvents prepare when the (meth) acrylate component of these copolymers has at least considerable proportions or even predominantly residues of longer-chain alcohols. As longer-chain alcohols here are understood in particular those in the range of about C₁₆₋₃₀ and in particular those in the range of at least C₁₈, especially when considerable amounts - z. B. at least about 35% by weight of alcohols with at least 20 carbon atoms.

Such (meth) acrylate copolymers are particularly effective when used as pour point improvers or pour point depressants or pour point depressants. In principle, it is therefore desirable to use the highest possible content of (meth) acrylate components with such long-chain alcohol residues. However, this creates another application-related difficulty: the longer the alcohol residue in the (meth) acrylate component, the higher the intrinsic pour point of the (meth) acrylate copolymer in the solvent used, so that difficulties in practical handling and in particular the metering under conditions of use are such organic solvents of dissolved concentrates. At present, experts can avoid these difficulties only by providing and using the pour point improvers in comparatively low concentrations in the solvent and / or by nevertheless having considerable proportions of comparatively lower alcohols in the range of, in particular, C₁₂₋₁₆ in the preparation of the (meth ) acrylate copolymers can also be used. It is clear that both measures are associated with restrictions and disadvantages.

The proposed solution according to the invention for accomplishing the task described here goes a completely new way in practice. The teaching of the invention is based on the surprising finding that the effective use of flow improvers described type does not require the prior dissolution of the polymeric (meth) acrylate copolymer compound in an organic solvent, but that it is possible - particularly under the measures described below in connection with the invention - to use a completely different form of supply of the copolymers. According to the invention, the polymeric active ingredients are used in the form of aqueous emulsion copolymers.

Accordingly, the invention relates in a first embodiment to the use of pour point-lowering copolymers of (meth) acrylic acid esters of long-chain alcohols and ethylenically unsaturated mono- and / or dicarboxylic acids with up to 10 carbon atoms and / or the anhydrides of such dicarboxylic acids in the form of the disperse Phase of aqueous emulsion copolymers as a highly concentrated, yet easily mobile form of supply for incorporation into hydrocarbon mixtures, in particular petroleum or petroleum fractions.

In a further embodiment, the invention relates to water- and oil-dilutable, mobile aqueous emulsion copolymers containing, as main components, about 20 to 70% by weight, preferably about 30 to 50% by weight, of copolymers of (meth) acrylic acid esters of higher alcohols with up to 30 Carbon atoms and ethylenically unsaturated mono- and / or dicarboxylic acids and / or the anhydrides of these dicarboxylic acids with up to 10 carbon atoms as the disperse phase,
about 0.1 to 7% by weight of oil-in-water emulsifiers,
up to about 35% by weight of water- and oil-soluble solubilizers and / or
up to about 7% by weight of water-in-oil emulsifiers and
Water as a continuous phase.

Taking into account the current practice of improving the flow and reducing the pour point of the polymer substances of the type concerned here, always in a pre-dissolved state - namely in an organic solvent such as toluene - to add the crude oils to be treated, petroleum fractions or other hydrocarbon mixtures, lies in the action according to the invention and with Results that are comparable to or even better than those of the prior art. If one takes into account that the additives in the ppm range - based on the hydrocarbon material to be treated - are used and that what is important for the effectiveness of these compounds is an interaction, which is not known in detail, with the interfering components, in particular the higher paraffins and / or naphthenes, it seems logical and necessary to introduce the flow-improving and pour point-lowering polymer compounds in activated form into the hydrocarbon material to be treated. This is not the case in the context of the teaching according to the invention. Here the polymer compounds are present as a disperse, practically solvent-free, optionally at least partially solidified organic phase in the homogeneous aqueous phase. When such aqueous emulsion polymers are mixed into the hydrocarbon mixture to be treated, the polymer substance first has to undergo a phase inversion. It must pass from the disperse aqueous phase into the continuous closed organic phase, must dissolve in it and thus pass through the activation step in order to then finally interact with the components who are responsible for the high stock and flow points. On the one hand, the teaching according to the invention is based on the unexpected finding that the desired effect also occurs in the hydrocarbon material in need of treatment if the flow improvers are used in the form of the emulsion copolymers described.

For the invention, however, further advantages in practical action are derived which make up the other part of the concept according to the invention:
If the copolymeric active ingredient is made available and used in the form of an aqueous emulsion copolymer, then the flowability of the active ingredient in practical use becomes independent of the particular constitution of the copolymer and very largely also of its concentration in the aqueous / organic active ingredient mixture. The viscosity of aqueous emulsion polymers can be controlled in a manner known per se in such a way that high flowability is ensured at low viscosities and considerable solids concentrations. For the nature of the (meth) acrylic acid copolymer, this means in particular that it is now safe to use those (meth) acrylate esters with, in particular, long-chain alcohols, which give optimum results in terms of lowering the pour point and pour point, without having regard to the pour point of these auxiliaries in organic solvents should be taken, as is the case with previous work. At the same time, these can be used in practical operation, predominantly or even exclusively, on the basis of (meth) acrylate esters with higher alcohols and copolymers in high active ingredient concentration.

In a preferred embodiment of the invention, the necessary phase reversal when mixing in the to facilitate and / or accelerate aqueous emulsion copolymers in the hydrocarbon mixtures to be treated, in particular petroleum or petroleum fractions, by using selected mixture components in the aqueous emulsion copolymers.

A first embodiment of this provides that aqueous emulsion copolymers of the type described are used, to which additional components have been added, which are distinguished both by water solubility or water miscibility and by oil solubility or oil miscibility. Preferred examples of such components are polyfunctional alcohols and / or ethers which are characterized on the one hand by their compatibility with water and on the other hand with hydrocarbon phases. Typical examples of compounds of this type are ethylene glycol, its partial ethers with, in particular, lower monofunctional alcohols and polyethylene glycols, which can also be at least partially etherified. The propanediols are further examples, but glycerol is very particularly preferred. Corresponding polyfunctional alcohols and / or ethers or partial ethers with an even higher carbon number are also suitable. Other components, for example selected ketones, which are distinguished by their ability to be miscible with water and oil, can also be used in addition to or instead of the aforementioned compounds.

Solubilizers of the type mentioned here are preferably used in amounts of up to about 35% by weight, based on the aqueous emulsion copolymer, although it may be preferred to use at least about 5% by weight and in particular at least about 10 to 20% by weight of these auxiliaries to use.

In a second embodiment of the inversion promotion discussed here, the aqueous one is provided according to the invention Add water-in-oil emulsifiers to emulsion copolymers. This addition takes place preferably after the production of the aqueous emulsion copolymers. These W / O emulsifiers can be used in addition to or instead of the water and oil-miscible compounds of the aforementioned type. The amounts of the W / O emulsifiers used are usually in the range up to about 5% by weight, again based on the aqueous emulsion copolymer. Typical examples of such W / O emulsifiers are, for example, the representatives described in HOUBEN-WEYL, Methods of Organic Chemistry, 4th Edition 1959 Volume 1, Part 2, 109/110 and 113 ff, in particular table pages 129 to 136 known class of substances.

The aqueous emulsion copolymers used according to the invention can have viscosities in a wide range. Since the viscosity of such a copolymer can also be determined, inter alia, by the solids concentration, there is a further possibility of variation in this respect. However, for the process of mixing in the aqueous emulsion copolymer with inversion of its disperse phase and solution in the hydrocarbon mixtures to be treated, it is advantageous to use materials which are distinguished by comparatively low viscosity values. These low viscosity values can be specified as such in the aqueous emulsion copolymer, but if desired they can also be adjusted by diluting more viscous aqueous emulsion copolymer compositions with water or an aqueous / organic phase composed of water and auxiliary solvents - for example the type of polyfunctional alcohols and / or their ethers described above will. For processing, viscosity values of the aqueous emulsion copolymers of at most about 10,000 mPas are preferred, in particular viscosity values not more than about 5000 mPas. Materials whose flowability extends to the order of magnitude of water, for example those with viscosity values in the range of about 100 to 3000 mPas can be particularly suitable. All viscosity values mentioned here relate to their determination as Brookfield viscosity (RTV, 20 ° C, 20 rpm).

Particularly suitable for the teaching of the invention are (meth) acrylate copolymers of the type described, in which the alcohol residues are predominantly or exclusively long-chain alcohol residues with preferred chain lengths in the range of at least C₁₈, preferably at least C₂₀. At least 50 mol%, preferably at least 80 mol%, of residues of this type are present in long-chain alcohol mixtures which are usually used for the preparation of this monomer component. These alcohols or alcohol residues are preferably predominantly corresponding compounds with n-alkyl residues. The alcohols themselves can be of natural and / or synthetic origin. Corresponding alcohol fractions of natural origin are, for example, predominantly fractions containing behenyl alcohol.

The concomitant use of acrylic acid and / or methacrylic acid or the other monocarboxylic acids of the C number range mentioned and / or the concomitant use of corresponding dicarboxylic acids or their anhydrides then leads to particularly effective copolymers if comparatively high contents of alcohol residues with at least 22 C atoms in the (Meth) acrylate copolymer are present. So it can be useful in the context of the invention to use alcohol cuts for the production of the acrylate components, the content of C₂₂ alcohol is at least about 25 wt .-%, preferably at least about 35 wt .-% and in particular at least about 45 wt .-% . Particularly good pour point improvers are obtained if these long-chain alcohol components in the alcohol cuts used to produce the (meth) acrylate component are above 50% by weight. The weight percentages given here relate on the content of C₂₂ alcohols - and optionally higher alcohols - in the alcohol mixture that has been used for the production of the (meth) acrylate components.

Particularly suitable comonomers for the emulsion copolymerization with the (meth) acrylates of the type described are mono- and / or dicarboxylic acids or their anhydrides with up to 6 carbon atoms. Particularly preferred examples are acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, maleic anhydride and / or fumaric acid.

Particularly suitable (meth) acrylate copolymers contain the mono- and / or dicarboxylic acids or their anhydrides used as comonomers in amounts of up to about 50% by weight and preferably in amounts of up to about 40% by weight. The most advantageous amounts in each case can be determined by considering the stability of the aqueous emulsion copolymers formed, although here the general knowledge of emulsion copolymerization must also be taken into account and goes into the production process of the active ingredient mixtures used according to the invention.

It has been shown that the production of low-coagulum and storage-stable aqueous emulsion copolymers of the type in question with high contents of (meth) acrylic acid esters of long-chain alcohols becomes all the more difficult, the higher the content of long-chain alcohol residues in the copolymer molecule and the longer the alcohol residues concerned will. Stability problems can therefore occur in particular if - for example in the context of the task according to the invention - long-chain alcohols (C₂₂ and more) as possible - are to be incorporated into the copolymer molecule in as high a concentration as possible. Conventional O / W, emulsifiers may not be sufficient in their stabilizing effect to ensure the required stable dispersion state. However, the copolymer class selected according to the invention is already relieved by the fact that the mono- and / or dicarboxylic acids or their anhydrides described are also used as comonomers. The use of precisely this class of comonomers leads to an additional stabilization of the disperse organic phase formed in the emulsion copolymerization. Depending on the composition of the multicomponent mixture used, it may be necessary to use comparatively large amounts of the carboxylic acid components. This applies in particular if only monocarboxylic acids are used as comonomers. If the additional required stability of the dispersion is to be set through their use, it may be necessary to use comparatively large amounts - for example 20 to 40% by weight of monocarboxylic acid, based on the total weight of the organic components to be polymerized. Dicarboxylic acids and / or their anhydrides as comonomers can be used in comparatively small amounts, for example in amounts of about 5 to 20% by weight - same reference basis - and even in these amounts show even when using high proportions of particularly long-chain alcohol residues in the copolymer Molecule remarkable stabilizing effects.

The binding of the dispersion stability described here to the concomitant use of considerable minimum amounts of mono- and / or dicarboxylic acids or their anhydrides can lead to a restriction in the free choice of the copolymer composition solely from the point of view of optimal effect with regard to improving the flow properties or lowering The pour and pour point of the substance mixtures to be treated.

In another embodiment, the invention provides an effective remedy as follows: It has been shown that the Problems of the lack of emulsion or dispersion stability of the organic copolymer phase can then be substantially reduced if, in addition to the comonomer components previously discussed, a third class of substances is used in comparatively small amounts in the copolymerization. These are (meth) acrylic acid esters of short-chain alcohols. The alcohol component of these comonomers preferably has a maximum of 8 carbon atoms and is particularly limited to 4 carbon atoms. Typical examples of compounds of this type are ethyl and / or butyl (meth) acrylate. These (meth) acrylates of short-chain alcohols are used in amounts of at most 25% by weight, preferably in amounts of not more than 20 and in particular not more than 15% by weight, based in each case on the comonomer mixture. Effective stabilizing effects - even if the content of mono- and / or dicarboxylic acids or their anhydrides in the copolymer molecule are reduced sharply at the same time - are obtained when the amount of these lower (meth) acrylates is in the range from about 5 to 10% by weight ( based on copolymer weight).

This stabilization of the copolymers described, based on (meth) acrylates of long-chain alcohols with a high carbon number in the alcohol residue and high concentration of this component in the copolymer molecule in aqueous dispersion copolymers, is part of the invention described here, which is also detached from the specific application from the previous description of the invention see is.

The invention accordingly relates in a further embodiment to stabilized aqueous emulsion copolymers of (meth) acrylic acid esters of long-chain alcohols in the closed aqueous phase, the invention being characterized in that these emulsion copolymers as Storage-stable disperse phase copolymers of the following monomer components contain:
at least 50 wt .-%, preferably at least 60 wt .-% (meth) acrylic acid ester of C₁₆₋₃₀ alcohols
up to 25 wt .-%, preferably 5 to 10 wt .-% (meth) acrylic acid ester of alcohols with not more than 8 carbon atoms as well
0.5 to 40% by weight and preferably about 1 to 25% by weight of olefinically unsaturated mono- and / or dicarboxylic acids or their anhydrides with preferably no more than 10 carbon atoms.

Corresponding aqueous emulsion copolymers which contain not more than about 10% by weight of (meth) acrylic acid esters of short-chain alcohols, 0.1 to 15% by weight and in particular about 1 to 10% by weight of the mono- and / or Contain dicarboxylic acids or their anhydrides and the remainder the (meth) acrylic acid esters of the long-chain alcohols as a disperse organic phase in the aqueous emulsion copolymer. Otherwise, the general numerical values given above apply to the particularly preferred composition of the copolymers or their respective components.

By using the last-mentioned embodiment of aqueous copolymers, it is possible to achieve a practically optimal adaptation of the structure of the copolymer molecule to the requirements of an optimal lowering of pour point or pour point.

The special composition of the respective copolymer types is determined in particular by their effectiveness in the hydrocarbon mixture to be improved in the flow behavior, represented in particular as petroleum or petroleum fraction. However, it is true that it is often difficult to make reliable predictions about the optimal amount of acrylate ester and acid comonomer in each individual case. The optimal mixing ratios must then be determined from case to case on the hydrocarbon mixture to be treated. The basis for this should be that the respective composition of the crude oils or crude oil fractions of different origins is very different from one another and that there is still no reliable explanation of the mechanism of action for lowering the pour point or improving the flow properties. As already said at the beginning, it is assumed that the copolymer types added in the ppm range in the treated hydrocarbon material - in particular through interaction with naphthenes and / or higher disruptive paraffin components - become effective in the sense of a thres hold effect. The form of supply of the aqueous emulsion copolymers chosen according to the invention now allows, for the first time, a practically trouble-free optimization in the structure of the disperse copolymer phase and its adaptation to the conditions given by nature.

For the preferred amounts of, for example, acrylic acid and / or methacrylic acid in the copolymer, a broad range of, for example, about 1 to 40% by weight, based on the weight of the copolymer, may be suitable. Taking into account the emulsion stability, amounts in the higher range, for example amounts of about 15 to 40, in particular 20 to about 35,% by weight of the monocarboxylic acid (s) can be of particular importance. On the other hand, for optimal effectiveness with regard to lowering the pour point and improving the flow properties, it may be desirable to polymerize comparatively lower proportions of the monocarboxylic acids, for example in the range from about 1 to 25% by weight and in particular in the range from about 5 to 15% by weight, based in each case on the copolymer weight.

If dicarboxylic acids or dicarboxylic anhydrides of the maleic anhydride type are used, it may be expedient to restrict such comonomers to amounts of at most about 20% by weight and preferably not more than 10% by weight. Maleic anhydride can be processed, for example, in amounts of about 5 to 10% by weight, based on the copolymer weight, to give very stable emulsion copolymers which at the same time bring about an optimal reduction in the pour and pour points.

In a particular embodiment, it may be desirable to take into account the details of the earlier applications mentioned DE-A-3807395 and DE-A-3807394 when composing the (meth) acrylic copolymers. Accordingly, the following applies to the composition of the copolymers for these embodiments:
Particularly suitable copolymers, together with the acrylic and / or methacrylic acid esters of higher alcohols or alcohol cuts, contain about 0.5 to 15% by weight of the free monocarboxylic acids mentioned, copolymers of the type mentioned having free acid contents in the range from about 1 to 10 % By weight may be particularly suitable. The most important copolymers of the type used in accordance with the invention contain acrylic acid and / or methacrylic acid as comonomers in the copolymer shown above in amounts of about 1.5 to 5.0% by weight. All these percentages by weight relate to the copolymer weight.

A preferred embodiment is also the use of copolymers of acrylic and / or methacrylic acid esters of higher alcohols or alcohol cuts with at least 16 carbon atoms in the alcohol residue and not more than 5% by weight of maleic anhydride. % By weight based on copolymer weight. Copolymers of the type mentioned whose content of maleic anhydride is in the range from approximately 0.5 to 2.5% by weight and in particular in the range from approximately 1 to 2% by weight are particularly suitable for the inventive action. Here, too, the percentages by weight relate to the copolymer weight.

It is part of the teaching according to the invention that the pour points of the crude oils and / or petroleum fractions used with their starting or intrinsic pour points above 25 ° C. and in particular above 30 ° C. by adding the flow improvers defined according to the invention to values below 15 ° C. and preferably below 10 ° C. According to the invention, it is possible, for example, to add pour points in the range from about 0 to 10 ° C. by adding conventional amounts of the pour point improvers in the sense of the invention. This ensures trouble-free handling of these crude oils and oil fractions under normal everyday conditions. In particular, it is ensured that lines, distributors and the like which are guided under water can be operated without problems.

The application concentration of the pour point improvers according to the invention is in the conventional range and is, for example, 20 to 1000 ppm, with amounts in the range from 100 to 500 ppm being preferred.

The emulsion copolymerization is carried out in a manner known per se. Reference is made, for example, to Ullmann's Encyclopedia of Industrial Chemistry, 4th edition, volume 19, 132 to 145.

Limited amounts of oil-in-water emulsifiers are usually used to prepare and stabilize the disperse polymer phase in the closed aqueous phase. Anionic or nonionic emulsifiers or their emulsifiers are particularly suitable Mixtures. For example, sulfates or sulfonates of long-chain alcohols or alkylphenols can be used, furthermore alkylbenzenesulfonates or sulfosuccinates. The sulfates of the reaction products of ethylene oxide and (fatty) alcohols or alkylphenols are also suitable, the base bodies being preferred nonionic emulsifiers. Further nonionic emulsifiers are sorbitan esters of long-chain fatty acids, ethoxylated sorbitan esters of long-chain fatty acids and alkyl glycerides. The emulsifiers can usually be used in amounts of about 0.01 to 5% by weight, preferably in amounts of about 0.1 to 3% by weight, in each case based on the weight of the monomers. The usual peroxide compounds, for. B. inorganic persulfate compounds such as alkali or ammonium persulfate, hydrogen peroxide, organic hydroperoxides` z. B. benzoyl peroxide, acetyl peroxide, peracids such as peracetic acid and perbenzoic acid or other free radical-providing materials such as 2,2'-azobisisobutyronitrile. In addition, other auxiliaries for emulsion polymerization can be used, such as buffering agents, inorganic salts and pH regulators.

The copolymerization is usually carried out at temperatures in the range between about 60 and 90 ° C., although higher or lower temperatures can also be used.

Examples 1. General preparation instructions for the preparation of dispersions based on poly (behenyl acrylate-co-maleic acid) apparatus

The reaction is carried out in a standard laboratory apparatus consisting of a double-wall glass reactor, stirrer, reflux condenser and heated dropping funnel.

raw materials

C₁₆₋₁₈ behenyl acrylate * ⁾ 810 g Maleic anhydride 90 g Dehydrophen ^(R) 100 * ⁾ 100 g (NH₄) ₂S₂O₈ 1 g Water, dist. 1000 g * ⁾ see information according to table 1

method

828 g of distilled water, 100 g of Dehydrophen 100 ^(R) and 90 g of maleic anhydride are placed in the reactor and heated to 85 to 90 ° C. within 60 minutes. 243 g of melted behenyl acrylate (50 ° C.) are added and emulsified for 15 minutes at a stirrer speed of 140 rpm. At this point, 0.4 g of ammonium peroxydisulfate dissolved in 10 g of water are added in one portion.

Exactly 15 minutes after this addition, a. an initiator solution consisting of 0.4 g ammonium peroxodisulfate in 160 g water and b. the monomer melt from 567 g of behenyl acrylate at 50 ° C within 30 minutes at a constant dosing rate from two separate dosing funnels.

30 minutes after the complete addition of monomer and initiator, 0.2 g of ammonium peroxodisulfate dissolved in 2 g of water are added in one portion as a post-initiator.

The post-reaction time is 90 minutes.

After the product has cooled to 20 ° C., the dispersion is filtered through a filter bag (80 μm) and filled.

The filter bag is washed out, and the coagulum present is indicated as a% residue, based on total monomer, after drying.

The stirring speed during the reaction is 140 rpm.

The properties of the dispersion are summarized in Table 1 (Example 1). Examples 2 to 11 were prepared by analogous processes.

2. General preparation instructions for the preparation of the dispersions based on poly (behenyl acrylate-co-acrylic acid) apparatus

The reaction is carried out in a standard laboratory apparatus consisting of a double-wall glass reactor, stirrer, reflux condenser and heated dropping funnel.

raw materials

C _16/18 behenyl acrylate 280 g Acrylic acid 70 g Dehydrophen ^(R) 100 25 g Texapon ^(R) N 25 25 g (NH₄) ₂S₂O₈ 0.5 g Water, dist. 600 g

method

514 g of distilled water, 25 g of dehydrophen 100 and 25 g of Texapon N 25 are placed in the reactor and heated to 85 to 90 ° C. within 60 minutes. 280 g of melted behenyl acrylate (50 ° C.) and 70 g of acrylic acid are mixed and 30% by weight of this mixture is emulsified in the reactor for 15 minutes at a stirrer speed of 140 rpm. At this point, 0.2 g of ammonium peroxodisulfate, dissolved in 5 g of water, is added in one portion.

Exactly 15 minutes after this addition, a. an initiator solution consisting of 0.2 g ammonium peroxodisulfate in 180 g water and b. the remaining 70% by weight of the monomer melt composed of behenyl acrylate and acrylic acid are added at 50 ° C. within 30 minutes at a constant metering rate from two separate metering funnels.

30 minutes after the complete addition of monomer and initiator, 0.1 g of ammonium peroxodisulfate in 1 g of water are added in one portion as a post-initiator.

The post-reaction time is 90 minutes. Then it is cooled.

The stirrer speed during the reaction is 140 rpm.

The properties of the dispersion are summarized in Table 2 (Example 18). Examples 12 to 21 were prepared by analogous processes.

3. Transfer of the water-dispersed polymers into the organic medium

• 1 a -
• 1 b Glycerin, 5 Gew. -%
• 1 c Glycerin, 10 Gew.-%
• 1 d Propandiol-1,2, 10 Gew.-%

Es resultieren jeweils homogene Gemische. Jeweils 5 g dieser Gemische werden mit 95 g Xylol bei Raumtemperatur mit einem Magnetrührer (Mischzeit 10 Minuten) vermengt. Die Mischungen werden gelagert, die Phasentrennung abgewartet (1,5 bis 4 Stunden) und die obere xylolische Phase mit einem Scheidetrichter abgetrennt. Die xylolische Phase wird eingedampft und das verbleibende Polymer im Vakuum bei 10 mbar und 100 °C getrocknet.The following alcohols are stirred into the dispersion according to Example 1 at room temperature (magnetic stirrer, mixing time 10 minutes):

• 1 a -
• 1 b glycerol, 5% by weight
• 1 c glycerin, 10% by weight
• 1 d 1,2-propanediol, 10% by weight

Homogeneous mixtures result in each case. 5 g of these mixtures are mixed with 95 g of xylene at room temperature using a magnetic stirrer (mixing time 10 minutes). The mixtures are stored, the phases are separated (1.5 to 4 hours) and the upper xylene phase is separated off with a separating funnel. The xylene phase is evaporated and the remaining polymer dried in vacuo at 10 mbar and 100 ° C.

The results of the tests are summarized in Table 3. Table 3 Inversion of dispersed poly (behenyl acrylate-co-maleic acid) particles from the aqueous dispersion into the organic solution attempt Emulsification of the dispersion in xylene Time required for phase separation / h Recovery rate polymer in the xylene solution /% by weight 1 a bad 1 20th 1 b moderate 2nd 38 1 c Good 4th 71 1 d Good 4th 29

Determination of the pour points

The pour point was determined in accordance with ASTM D 97-66 and DIN 51597 as follows:
25.0 Bombay crude oil together with 800 ppm of the 50% by weight dispersion of the flow improver were kept in a closed vessel at 50 ° C. for 15 minutes and shaken vigorously 5 times at regular intervals. The crude oil doped in this way was quickly poured into a cylindrical glass vessel with an inner diameter of 27 mm and this immediately sealed vessel is hung sufficiently deep in a water bath at + 36 ° C.

After 30 minutes the glass was tilted slightly to the side and observed whether the contents were flowing. The sample was then gradually cooled by 3 ° C and the test procedure was carried out each time. 3 ° C was added to the temperature at which the contents no longer flowed even when the test glass was inclined by 90 °, thereby determining the pour point.

The pour point of the untreated Bombay crude oil is 30 ° C according to this determination method. Table 4 Pourpoints in Bombay crude oil (OC) Example * ⁾ Pour point / ° C 1 9 3rd 12th 4th 12th 5 12th * ⁾ Original dispersions each mixed with 10% by weight glycerin as described under 3.

Claims (18)

1. The use of flow-point-depressing copolymers of (meth)acrylates of long chain alcohols and ethylenically unsaturated mono- and/or dicarboxylic acids containing up to 10 carbon atoms and/or anhydrides thereof in the form of the disperse phase of aqueous emulsion copolymers as a highly concentrated, but readily mobile formulation for incorporation in hydrocarbon mixtures, particularly in crude oil or petroleum fractions.
2. The use claimed in claim 1, characterized in that the emulsion polymers additionally contain limited quantities of (meth)acrylates of short-chain alcohols.
3. The use claimed in claims 1 and 2, characterized in that copolymers of (meth) acrylates with predominantly C₁₆₋₃₀ alcohols, more especially containing at least 35% by weight C₂₀ and longer-chain alcohols, are used.
4. The use claimed in claims 1 to 3, characterized in that copolymers of (meth)acrylates with mono- and/or dicarboxylic acids or anhydrides thereof containing up to 6 carbon atoms are used, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, maleic anhydride and/or fumaric acid preferably being present as comonomers.
5. The use claimed in claims 1 to 4, characterized in that copolymers additionally containing (meth)acrylates of short-chain alcohols with no more than 8 and preferably with no more than 4 carbon atoms in copolymerized form are used, the content of this component making up no more than 25% by weight and preferably from 5 to 10% by weight, based on the weight of the copolymer.
6. The use claimed in claims 1 to 5, characterized in that copolymers containing up to 50% by weight, preferably up to 40% by weight and, more preferably, from about 1 to 25% by weight of one or more comonomers are used.
7. The use claimed in claims 1 to 6, characterized in that aqueous emulsion copolymers additionally containing water- and oil-miscible components, more especially poly-functional alcohols and/or ethers, such as ethylene glycol, polyethylene glycols, propanediols, but especially glycerol, preferably in quantities of up to about 35% by weight (based on aqueous emulsion copolymer), are used.
8. The use claimed in claims 1 to 7, characterized in that aqueous emulsion copolymers which, instead of or in addition to the water- and oil-soluble compounds, contain water-in-oil emulsifiers, preferably in quantities of up to about 5% by weight, based on aqueous emulsion copolymer, having been added to the mixture in particular after preparation of the emulsion copolymer, are used.
9. The use claimed in claims 1 to 8, characterized in that aqueous emulsion copolymers having viscosities of at most 10,000 mPa.s, preferably below 5,000 mPa.s and more preferably in the range from about 100 to 3,000 mPa.s are used.
10. Water-dilutable and oil-dilutable, mobile aqueous emulsion copolymers containing as principal components about 20 to 70% by weight and preferably about 30 to 50% by weight copolymers of (meth)acrylates of higher alcohols containing up to 30 carbon atoms and ethylenically unsaturated mono- and/or dicarboxylic acids containing up to 10 carbon atoms and/or anhydrides thereof as disperse phase, about 0.1 to 7% by weight oil-in-water emulsifiers,
    up to about 35% by weight water- and oil-soluble solubilizers and/or
    up to about 7% by weight water-in-oil emulsifiers and water as continuous phase.
11. Aqueous emulsion copolymers as claimed in claim 10, characterized in that the copolymers contain limited quantities of (meth)acrylates of short-chain alcohols as an additional constituent.
12. Aqueous emulsion copolymers as claimed in claim 11, characterized in that the copolymer phase contains up to 50% by weight comonomers, preferably up to 40% by weight monocarboxylic acids and/or up to 20% by weight and more especially from about 5 to 10% by weight dicarboxylic acid or the corresponding anhydrides.
13. Aqueous emulsion copolymers as claimed in claims 11 and 12, characterized in that they contain polyfunctional alcohols and/or ethers, such as ethylene glycol, polyethylene glycols, propanediols, but especially glycerol, as water- and oil-soluble solubilizers.
14. Aqueous emulsion copolymers of (meth)acrylates of long-chain alcohols as claimed in claims 10 to 12, characterized in that they contain as storable disperse phase copolymers of the following monomer components:
    at least 50% by weight (preferably at least 60% by weight) (meth) acrylates of C₁₆₋₃₀ alcohols
    0 to 25% by weight (preferably 5 to 10% by weight) (meth)acrylates of alcohols containing no more than 8 carbon atoms
    0.5 to 40% by weight (preferably 1 to 25% by weight) olefinically unsaturated mono- and/or dicarboxylic acids and/or anhydrides containing no more than 10 carbon atoms.
15. Emulsion copolymers as claimed in claim 14, characterized in that at least 50 mol-% and preferably at least 80 mol-% of the (meth)acrylates of long-chain alcohols emanate from alcohols containing at least 18 carbon atoms and, in particular, from corresponding alcohols containing at least 20 carbon atoms.
16. Emulsion copolymers as claimed in claims 14 and 15, characterized in that they contain (meth)acrylates of short-chain alcohols containing no more than 4 carbon atoms.
17. Emulsion copolymers as claimed in claims 14 to 16, characterized in that, in the absence of the (meth)acrylates of short-chain alcohols, they contain the free carboxylic acids or anhydrides in comparatively larger quantities within the ranges indicated.
18. Emulsion copolymers as claimed in claims 14 to 17, characterized in that they contain no more than 10% by weight (meth)acrylates of short-chain alcohols, from 0.1 to 15% by weight and more especially from 1 to 10% by weight of the mono- and/or dicarboxylic acids or anhydrides and, for the rest, the (meth)acrylates of long-chain alcohols as storable disperse copolymer phase.