ES2564579T3 - Novel surfactants for tertiary oil extraction based on branched alcohols - Google Patents

Abstract

Surfactants with the general formula R1-X, in which in the case of R1 it is an aliphatic alkyl radical C17H35- and in the case of X it is a hydrophilic group, characterized in that the average degree of branching of the radical R1 amounts to from 2.8 to 3.7, the degree of branching being the number of methyl groups in the R1 moiety minus 1.

Description

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DESCRIPTION

Novel surfactants for the extraction of tertiary oil based on branched alcohols

The invention relates to surfactants of the general formula R1-X, in which in the case of R1 it is a C17H35-aliphatic alkyl moiety and in the case of X it is a hydrophilic group, and the average degree of ramification of the remainder R1 amounts to 2.8 to 3.7. This also refers to mixtures containing surfactants of this type, as well as the use of surfactants of this type or mixtures thereof for the extraction of tertiary oil.

In natural oil fields oil is found in the cavities of porous storage rocks, which are isolated to the earth's surface by impermeable cover layers. In the case of cavities it can be very fine cavities, capillaries, pores or the like. The fine pore necks may, for example, have a diameter of only about 1 ^ m. In addition to oil, including proportions of natural gas, a reservoir contains water with a salt content more or less large. The salt content of the reservoir water is rarely 5% to 20% by weight; However, there are also deposits with a salt content of up to 27% by weight. In the case of dissolved salts, for example, they may be alkali metal salts, however in some deposits the reservoir water also contains relatively high proportions of alkaline earth metal ions, for example up to 5% by weight of calcium ions and / or magnesium ions.

In oil extraction, the difference between primary, secondary and tertiary extraction.

In the primary extraction, after the drilling of the deposit flows the oil due to the pressure of the deposit itself through the drilling hole in the surface. The pressure itself can be generated by existing gases in the reservoir such as methane, ethane or propane. However, by means of primary extraction, only approximately 5% to 10% of the amount of oil in the field can be extracted depending on the type of reservoir, as a result the pressure is no longer sufficient. Own for extraction.

After primary extraction, therefore, secondary extraction is used. In secondary extraction, in addition to the drilling holes that are used for oil extraction, the so-called production perforations, other drilling holes are drilled in the formation that conducts oil. Through these so-called injection perforations, water is introduced under pressure into the reservoir to maintain the pressure or increase it again. By introducing the water pressure, the oil is pressed through the cavities in the formation slowly starting from the injection perforation towards the production perforation. However, this works only for as long as the cavities are completely filled with oil and the more viscous oil continuously moves through the water (see Figure 1). As soon as the very fluid water leaves the cavities, it flows from this moment on the way to the lowest resistance, that is, through the formed channel and no longer continuously displaces the oil. This situation is represented in figure 2: due to the different polarity of oil and water, a high surface energy limit or surface tension is limited between the two components. Therefore they both adopt the smallest surface with respect to each other, which results in a drop of oil in the form of a sphere that no longer passes through the thin capillaries. At the end of the water thrust, the oil is therefore captured discontinuously (isolated spherical drops) in the capillaries.

By means of primary and secondary extraction, in the normal case only approximately 30% to 35% of the amount of oil in the field can be extracted.

It is known to subsequently increase the oil yield by means of tertiary extraction measures. A summary regarding tertiary oil extraction is found, for example, in the Journal of Petroleum Science and Engineering 19 (1998) 265-280. To the extraction of tertiary oil belong thermal procedures in which hot water or hot steam is introduced under pressure in the field. This reduces the viscosity of the oil. Gases such as CO2 or nitrogen can also be used as an injection medium.

In addition to tertiary oil extraction, there are also procedures in which suitable chemical products are used as adjuvants for the extraction of oil. With these, the situation at the end of the water thrust can be influenced and due to this the oil retained until then in the rock formation can also be extracted.

On the oil that is captured at the end of the secondary extraction in the pores of the reservoir rock, viscous and capillary forces act, determining the proportion of these two forces with respect to each other the microscopic separation of the oil. By means of a dimensionless parameter, the so-called capillary number, the action of these forces is described. This is the proportion of the viscosity forces (velocity x viscosity of the pressing phase) with respect to the capillary forces (surface tension limit between oil and water x rock wetting):

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In this respect it means | i the viscosity of the fluid that mobilizes the oil, and the speed of Darcy (flow rate per unit area), to the surface tension Kmite between the liquid that mobilizes the oil and the oil and 0 the angle of contact between oil and rock (C. Melrose, CF Brandner, J. Canadian Petr. Techn. 58, Oct.-Dec., 1974). The higher the capillary number, the greater the mobilization of oil and therefore also the degree of oil withdrawal.

It is known that the capillarity number at the end of the extraction of secondary oil is in the range of approximately 10 "6 and that it is necessary to raise the capillarity number to approximately 10" 3 to 10 "2 in order to mobilize additional oil.

For this, the limit surface tension between the oil and the aqueous phase can be reduced, for example, by the addition of suitable surfactants. This technique is also known as "surfactant thrust." For this purpose, surfactants that can reduce to values of <10 "2 mN / m (ultra low interfacial tension, ultralow interfacial tension) are suitable in particular. In this way the shape of the oil drops can be modified and these can be traversed by compression by Injection water capillary openings.

It is desirable that the oil droplets meet next to give a continuous oil bank. This is shown schematically in Figure 3. This has two advantages: on the one hand during the advance of the continuous oil bank by a new porous rock, the oil drops found there can be melted with the bank. Also, by grouping the oil droplets to give an oil bank, the oil-water limit surface is clearly reduced and therefore the necessary surfactant is no longer released. The released surfactant can mobilize after drops of oil left in the formation. This is shown schematically in Figure 4. Also for the grouping of the oil droplets to give an oil bank as well as for the absorption of new oil droplets in the oil bank an ultra low limit surface tension between the phase is necessary. Aqueous and the oil phase. Otherwise, individual oil drops fall behind or are not absorbed together in the oil bank. This reduces the effectiveness of the surfactant thrust.

In general, after the push by surfactant for the maintenance of the pressure, no water is injected into the formation, but an aqueous solution of higher viscosity of a highly thickening polymer. This technique is known as "push by polymer".

During the surfactant thrust, the surfactants with the aqueous phase and the oil phase must form a microemulsion (Winsor type III). In the case of a microemulsion (Winsor type III) it is not an emulsion with especially small drops, but a thermodynamically stable liquid mixture of water, petroleum and surfactants, which has a very low surface tension and has a mayonnaise of cases of low viscosity. This is in equilibrium with excess water and excess oil. A low viscosity is desirable for the transport of the emulsion in the oil formation. With a too high viscosity of the phase to be transported, a very high pressure should be used as a result of the polymer thrust. This is on the one hand expensive, however, above all there is also the risk that new cavities in the formation of oil will burst through the pressure. In addition, a grouping of the oil droplets mobilized to give a continuous oil bank in the case of too high viscosities is prevented.

The surfactant requirements for tertiary oil extraction clearly differ from the surfactant requirements for other applications.

Surfactants should reduce the surface tension limit between water and oil (usually approximately 20 mN / m) to especially low values below 10-2 mN / m to enable sufficient oil mobilization. This should be done at the usual reservoir temperatures of about 30 ° C to about 130 ° C and in the presence of water with a high salt content, in particular also in the presence of high proportions of calcium and / or magnesium ions; therefore the surfactants must also be soluble in reservoir water with a high salt content. The temperature range within which a microemulsion is formed should be as wide as possible in this regard. To avoid loss of surfactant in the formation, the surfactants should have a low tendency to form viscous or large surfactant superstructures as well as they should exhibit a low adsorption behavior. In addition, surfactants should have high chemical stability under the conditions prevailing in the formation. To this belongs, above all, high long-term stability: the speed of migration of the thrust by surfactant in the formation is often less than 1 m / day. Depending on the distance between the injection and extraction orifice, the residence times of the surfactant in the oil field can therefore rise to several months.

Various surfactants or mixtures of surfactants have already been proposed for use in tertiary oil extraction.

US 3,811,505 discloses a mixture of an anionic surfactant and a nonionic surfactant for use in reservoirs, whose reservoir water contains from 0.5% to 0.9% by weight of polyvalent ions. If

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of the anionic surfactants are alkyl sulphonates or alkyl phosphates with respectively 5 to 25 C atoms, alkylarylsulfonates or alkylarylsulfonates, whose alkyl moiety respectively has 5 to 25 C atoms. In the case of non-ionic surfactants it is polyethoxylated alkylphenols which they have 6 to 20 ethoxy groups and whose alkyl moiety has 5 to 20 Co atoms of polyethoxylated aliphatic alcohols with 6 to 20 C atoms and 6 to 20 ethoxy groups.

US 3,811,504 discloses a mixture of 2 different anionic surfactants and a non-ionic surfactant for use in reservoirs, whose reservoir water contains 0.15% to 1.2% calcium and magnesium ions. In the case of the first anionic surfactant it is alkyl sulphonates or alkylarylsulfonates, in the case of the second one it is alkyl polyethoxysulfates and in the case of the nonionic surfactant it is aliphatic or aromatic polyethoxylated alcohols. Mixtures of surfactants of the same composition are disclosed for example by US 3,508,621, US 3,811,507 or 3,890,239.

US 4,077,471 discloses a mixture of surfactants for use in a formation, whose reservoir water has a salt content of 7% to 22%. The mixture comprises a water-soluble alkylpolyalkoxyalkyl sulfonate or alkylarylpolyalkoxyalkyl sulfonate as well as a water-insoluble nonionic surfactant of an aliphatic ethoxylated alcohol or an ethoxylated, aromatic substituted alkyl alcohol.

EP 003 183 B1 discloses surfactants of the general formula R-O-polypropoxy-polyethoxy-X, wherein X is a sulfate, sulphonate, phosphate or carboxylic acid group. In the case of R it can be treated in a preferred embodiment of the invention of a branched alkyl moiety with 10 to 16 C atoms, for example an isotridecyl moiety.

US 3,675,716 discloses a mixture of an anionic surfactant and a branched alkoxylated alcohol sulfate, the branching site being no longer separated as a C atom from the C atom at which the sulfate group has been attached.

US 5,849,960 discloses branched alcohols with 8 to 36 atoms of C. The degree of branching amounts to at least 0.7 and preferably 1.5 to 2.3, with less than 0.5% being present. of quaternary C atoms, and the branches comprise methyl and ethyl groups. Further described is the subsequent processing of the alcohols to give the corresponding surfactants, and specifically alkoxylates, sulfates or alkoxysulfates as well as their use for the preparation of biodegradable washing agents.

EP 958 267 B1 discloses branched alcohols with 11 to 36 atoms of C. The degree of branching amounts to at least 0.7 to 3.0, preferably 1.5 to 2.3, with less than 0.5% of quaternary C atoms, and the branches comprise methyl and ethyl groups. Further described is the subsequent processing of the alcohols to give the corresponding surfactants, and specifically alkoxylates, sulfates or alkoxysulfates as well as their use for the preparation of biodegradable washing agents.

US 6,222,077 discloses a process for the preparation of surfactants, in which linear C6 to C10 olefins are dimerized to give C12 to C20 olefins, the obtained olefins are reacted to give C13 to C21 alcohols and reacted the alcohols to give the corresponding branched surfactants. The average branching degree of the alcohols amounts to 0.9 to 2.0, with less than 25% of the branches being arranged in position C2 or C3 with respect to the OH group.

US 2006/0185845 A1 discloses the use of a mixture of at least one aliphatic anionic surfactant and a branched aliphatic nonionic surfactant for oil extraction. The branched aliphatic moiety preferably has 10 to 24 C atoms and the degree of branching amounts to 0.7 to 2.5.

US 2006/018486 discloses the use of a mixture of at least one branched aliphatic anionic surfactant and an aliphatic non-ionic surfactant for oil extraction. The branched aliphatic moiety preferably has 10 to 24 C atoms and the degree of branching amounts to 0.7 to 2.5.

The aim of the invention was to facilitate improved surfactants for the extraction of tertiary oil.

Correspondingly, surfactants of the general formula R1-X were found, in which in the case of R1 it is a C17H35- aliphatic alkyl moiety and in the case of X it is a hydrophilic group and the average branching degree of the remainder R1 amounts to 2.8 to 3.7, preferably 2.9 to 3.6.

In a preferred embodiment of the invention, in the case of X it is a group selected from the group of sulfonate groups, polyoxyalkylene groups, anionically modified polyoxyalkylene groups, glucoside groups or amine oxide groups.

In another preferred embodiment of the invention, these are mixtures of surfactants of at least two different surfactants, in the case of at least one of them being a R1-X surfactant.

In addition, the use of R1-X surfactants or mixtures thereof for tertiary oil extraction was found.

Figures attached:

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Figure 1 situation at the beginning of secondary oil extraction: rock pores completely filled with oil.

Figure 2 situation at the end of the extraction of secondary oil: the injection water has formed a channel and flows through the channel, without dragging additional oil.

Figure 3 schematic representation of the surfactant thrust in an oil formation: oil drops released from the rock pores before (A) and after (B) the grouping to give a continuous oil bank.

Figure 4 schematic representation of the progress of the continuous oil bank in the formation of oil. The oil bank absorbs new drops of oil in the direction of flow. Surfactant is released against the flow direction.

With regard to the invention, the following may be set forth in detail:

in the case of the surfactants according to the invention it is surfactants of the general formula R1-X, in which in the case of R1 it is a branched aliphatic alkyl radical C17H35-, whose average branching degree amounts to 2 , 8 to 3.7. Preferably, the degree of branching amounts to 2.9 to 3.6, especially preferably 3.01 to 3.5, very particularly preferably 3.05 to 3.4 and, for example, approximately 3.1.

In the case of X, it is a hydrophilic group that gives the molecule amphiphilic properties. In principle, they may be discretionary hydrophilic groups that are suitable for use as head groups in surfactants. The expert knows the corresponding hydrophilic groups.

The surfactants can be prepared starting from a branched aliphatic alcohol R1-OH with a branching degree of 2.8 to 3.7, preferably 2.9 to 3.6, especially preferably 3.01 to 3.5 of very particularly preferably from 3.05 to 3.4 and for example about 3.1.

The term "branching degree" is defined according to this in a manner known in principle as the number of methyl groups in a molecule of alcohol minus 1. The average branching degree is the statistical average value of the branching degrees of all the molecules of a sample. In other words, in the case of the alcohol R1-OH used it may be a mixture of different alcohols and correspondingly to this also in the case of the surfactants according to the invention it may be a mixture of different surfactants, which respectively they have different C17H35- aliphatic alkyl moieties.

The average branching degree can be determined by 1 H-NMR spectroscopy as follows: a sample of the alcohol is first subjected to a derivatization with trichloroacetyl isocyanate (TAI). In this respect the alcohols are transformed into esters of carbamic acid. The signals of the esterified primary alcohols are found at 8 = 4.7 to 4.0 ppm, those of the esterified secondary alcohols (as long as they are present) at approximately 5 ppm and the water in the sample reacts with TAI to give carbamic acid All methyl, methylene and methine protons are in the range of 2.4 to 0.4 ppm. Signals <1 ppm are assigned in this regard to methyl groups. From the spectrum thus obtained, the average branching degree (Iso index) can be calculated as follows:

Iso-Index = ((F (CH3) / 3) / (F (CH2-OH) / 2)) -1

F (CH3) representing the signal area corresponding to the methyl protons and F (CH2-OH) the signal area of the methylene protons in the CH2-OH group.

Facilitation of used R1-OH alcohols

The R1-OH alcohols can be synthesized basically according to any discretionary procedure, provided they present respectively the degree of branching described.

The R1-OH alcohols can be obtained for example from a branched C16 olefin by hydroformylation followed by hydrogenation of the aldehyde obtained to give the alcohol. The realization of a hydroformylation as well as the subsequent hydrogenation is known in principle by the expert. The C16 olefins used for this can be prepared by butene tetramerization.

Preferably, the C17 alcohol mixture can be prepared

a) providing a hydrocarbon feedstock, containing at least one olefin with 2 to 6 carbon atoms,

b) subjecting the hydrocarbon feedstock to oligomerization in a catalyst containing transition metal,

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c) subjecting the oligomerization product obtained in step b) to a distillation separation obtaining a flow of olefin enriched in C16 olefins,

d) subjecting the flow of olefin enriched in C16 olefins obtained in step c) to a hydroformylation by reaction with carbon monoxide and hydrogen in the presence of a cobalt hydroformylation catalyst and then to a hydrogenation.

Stage a) Facilitation of a hydrocarbon mixture

The olefin raw materials suitable for step a) are in principle all compounds containing 2 to 6 carbon atoms and at least one ethylenically unsaturated double bond. Preferably, a mixture of hydrocarbons containing olefins that is technically available is used in step a).

Mixtures of olefins that are available on a preferred technical scale result from the dissociation of hydrocarbons during oil processing, for example by catalytic cracking, such as fluid catalytic cracking (FCC), thermal cracking or hydrocracking with subsequent dehydrogenation. A preferred technical olefin mixture is the C4 fraction. The C4 fractions can be obtained for example by fluid catalytic cracking or steam cracking of diesel or by steam cracking of naphtha. Depending on the C4 fraction, the total C4 fraction (gross C4 fraction) is distinguished, the so-called refining I obtained after the 1,3-butadiene separation as well as the refining II obtained after the isobutene separation. Another suitable technical olefin mixture is the C5 fraction that can be obtained in the dissociation of naphtha. Mixtures of olefin-containing hydrocarbons suitable for use in step a) with 4 to 6 carbon atoms can be obtained additionally by catalytic dehydrogenation of suitable paraffin mixtures that are available on a technical scale. Thus, for example, the preparation of mixtures of C4 olefins from liquid gases (liquified petroleum gas, LPG) and natural fluidifiable gases (liquified natural gas, LNG) is successful. The latter also comprise, in addition to the LPG fraction, additionally larger amounts of higher molecular weight hydrocarbons (light naphtha) and are therefore also suitable for the preparation of mixtures of C5 and C6 olefins. The preparation of hydrocarbon mixtures containing olefins, containing monoolefins with 4 to 6 carbon atoms, from LPG or LNG flows is achieved according to usual procedures known to the expert, which in addition to dehydrogenation generally comprise even a or several stages of processing. This includes, for example, the separation of at least part of the saturated hydrocarbons contained in the initial olefin mixtures mentioned above. These can, for example, be used again for the preparation of olefin raw materials by cracking and / or dehydrogenation. The olefins used in step a) may, however, also contain a proportion of saturated hydrocarbons that behave inertly with respect to the oligomerization conditions. In general, the proportion of these saturated components amounts to a maximum of 60% by weight, preferably to a maximum of 40% by weight, particularly preferably to a maximum of 20% by weight, with respect to the total amount of saturated hydrocarbons and olefins contained in the hydrocarbon feedstock.

Preferably, a mixture of hydrocarbons containing from 20% to 100% by weight of C4 olefins, from 0% to 80% by weight of C5 olefins, from 0% to 60% by weight of C6 olefins is provided in step a) from 0% to 10% by weight of olefins other than the olefins mentioned above, respectively with respect to the total olefin content.

Preferably, a mixture of hydrocarbons having a linear monoolefin content of at least 80% by weight, particularly preferably at least 90% by weight and in particular at least 95% by weight, is preferably provided in step a) with respect to the total olefin content. In this regard, the linear monoolefins are selected from 1-butene, 2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, 3-hexene and mixtures thereof. For the adjustment of the desired branching degree of the isoalkane mixture it may be advantageous when the hydrocarbon mixture used in step a) contains up to 20% by weight, preferably up to 5% by weight, in particular up to 3% by weight. weight of branched olefins, with respect to the total olefin content.

Particularly preferably, a mixture of C4 hydrocarbons is provided in step a).

The butene content, with respect to 1-butene, 2-butene and isobutene, of the C4 hydrocarbon mixture provided in step a) preferably amounts to 10% to 100% by weight, especially preferably 50% to 99% by weight, and in particular from 70% to 95% by weight, with respect to the total olefin content. Preferably, the ratio of 1-butene with respect to 2-butene is in a range of 20: 1 to 1: 2, in particular in about 10: 1 to 1: 1. Preferably, the C4 hydrocarbon mixture used in step a) contains less than 5% by weight, in particular less than 3% by weight of isobutene.

The facilitation of the olefin-containing hydrocarbons in step a) may comprise a separation of branched olefins. The usual separation procedures, known in the state of the art, which are based on different physical properties of linear and branched olefins or based on different reactivities that allow selective reactions are suitable. Thus, for example, isobutene can be separated from mixtures of C4 olefins, as refining I, by one of the following procedures: molecular sieve separation, fractional distillation, reversible hydration to give tert-butanol, addition of acid catalyzed alcohol to an ether

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tertiary, for example adding methanol to give methyl tert-butyl ether (MTBE), irreversible catalyzed oligomerization to give di- and tri-isobutene or reversible polymerization to give polyisobutene. Procedures of this type are described in K. Weissermel, H.-J. Arpe, Industrielle organische Chemie, 4th edition, p. 76-81, VCH- Verlagsgesellschaft Weinheim, 1994, to which reference is made in its entirety herein.

Preferably, refining II is provided in step a).

A refining II suitable for use in the process has for example the following composition: from 0.5% to 5% by weight of isobutane, from 5% to 20% by weight of n-butane, from 20% to 40% in weight of trans-2-butene, from 10% to 20% by weight of cis-2-butene, from 25% to 55% by weight of 1-butene, from 0.5% to 5% by weight of isobutene as well as trace gases, such as 1,3-butadiene, propene, propane, cyclopropane, propadiene, methylcyclopropane, vinylacetylene, pentenes, pentanes in the range of respectively at most 1% by weight.

A particularly suitable refining II has the following typical composition: i-butane: 3% by weight, n-butane: 15% by weight, i-butene: 2% by weight, butene-1: 30% by weight, butene-2 -trans: 32% by weight, butene-2-cis: 18% by weight.

If diolefins or alkynes are present in the olefin-rich hydrocarbon mixture, then these can be separated from them before oligomerization until preferably less than 100 ppm is obtained. These are preferably separated by selective hydrogenation, for example in accordance with EP-81 041 and DE-15 68 542, especially preferably by selective hydrogenation until a residual content of less than 50 ppm is obtained.

The oxygen-containing compounds, such as alcohols, aldehydes, ketones or ethers, are also conveniently separated from the olefin-rich hydrocarbon mixture. For this purpose, the olefin-rich hydrocarbon mixture can be conducted advantageously through an adsorption medium, such as a molecular sieve, in particular one with a pore diameter of> 4 A to 5 A. The concentration of oxygen-containing compounds , which contain sulfur, which contain nitrogen and which contain halogen in the olefin-rich hydrocarbon mixture preferably amounts to less than 1 ppm by weight, in particular less than 0.5 ppm by weight.

Stage b) Oligomerization

In the context of the preparation process described for C17 alcohols, the term "oligomers" includes dimers, dimers, tetramers, pentamers and superior products of the reaction of construction of the olefins used. The oligomers are in turn olefmically unsaturated. By suitable choice of the hydrocarbon feedstock used for oligomerization and the oligomerization catalyst, as described below, an oligomerization product containing C16 olefins can be obtained which can be further processed advantageously to give the mixture of C17 alcohols. used according to the invention.

For the oligomerization in step b) a reaction system comprising one or several same or different reactors can be used. In the simplest case, an individual reactor is used for oligomerization in step b). However, several reactors that have the same or different mixing characteristics respectively can also be used. The individual reactors can be subdivided in a simple way or optionally varied by modules. If two or more reactors form the reaction system, then these can be connected to each other in a discretionary manner, for example in parallel or in series. In a suitable embodiment, for example, a reaction system is used which is constituted by two reactors connected in series.

Suitable pressure-resistant reaction apparatus for oligomerization is known to the expert. To this belong the usual reactors for gas-solid and gas-liquid reactions, such as tubular reactors, stirring vessels, gas circulation reactors, blow columns etc., which may eventually be subdivided by modules. Preferably tubular beam reactors or vat furnaces are used. If a heterogeneous catalyst is used for oligomerization, then it may be arranged in a single solid bed of catalyst or in several solid beds of catalyst. In this regard it is possible to use different catalysts in different reaction zones. However, the use of the same catalyst in all reaction zones is preferred.

The temperature during the oligomerization reaction is generally in a range of about 20 ° C to 280 ° C, preferably from 25 ° C to 200 ° C, in particular from 30 ° C to 140 ° C. The pressure during oligomerization is generally in a range of about 100 kPa to 30,000 kPa, preferably 500 kPa to 10,000 kPa and in particular 2,000 kPa to 7,000 kPa. If the reaction system comprises more than one reactor, then these may have the same or different temperatures and the same or different pressures. Thus, for example, in the second reactor of a cascade of reactors a higher temperature and / or a higher pressure than in the first reactor can be set, for example to achieve the most complete conversion possible.

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In a special embodiment, the temperature and pressure values used for oligomerization are selected so that the olefin-containing raw material is liquid or in the super-quantum state.

The reaction in step b) is preferably performed adiabatically. This term is understood below in the technical sense and not in the physical-chemical sense. Thus, the oligomerization reaction generally runs exothermically, so that the reaction mixture when flowing through the reaction system, for example a catalyst bed, experiences an increase in temperature. The adiabatic reaction conduction means a method of procedure in which the amount of heat that is released in an exothermic reaction is absorbed by the reaction mixture in the reactor and no cooling is used by means of cooling devices. Accordingly, the heat of reaction with the reaction mixture is evacuated from the reactor, except for a residual ratio that is emitted to the environment by the reactor through natural thermal conduction and heat radiation.

For the oligomerization in step b) a catalyst containing transition metal is used. Preferably, they are heterogeneous catalysts in this regard. The preferred catalysts for the reaction in step a), which produce in a known manner a low branching of oligomers, are known to the general expert. To this belong the catalysts described in Catalysis Today, 6, 329 (1990), in particular pages 336-338, as well as the catalysts described in DE-A-43 39 713 (= WO-A 95/14647) and the Document DE-A-199 57 173, which is expressly referred to herein. A suitable oligomerization process in which the feed flow used for oligomerization is divided and fed to at least two reaction zones driven at different temperatures, is described in EP-A-1 457 475, to which It also refers.

Preferably an oligomerization catalyst containing mquel is used. In this regard, heterogeneous catalysts containing nickel oxide are preferred. Catalysts containing the heterogeneous compounds used may have different structures. In principle, complete catalysts are suitable as well as supported catalysts. The latter are preferably used. The support materials may be, for example, silica, clay, aluminum silicates, aluminum silicates with layer structures and zeolites, such as mordenite, faujasite, zeolite X, zeolite-Y and ZSM-5, zirconium oxide, which is treated with acids, or sulfated titanium dioxide. Precipitation catalysts that can be obtained by mixing aqueous solutions of nickel salts and silicates, for example sodium silicate with nickel nitrate, and possibly aluminum salts, such as aluminum nitrate, and calcination are especially suitable. In addition, catalysts which are obtained by deposition of Ni2 + ions by ionic exchange in natural or synthetic stratified silicates, such as montmorillonites, can be used. Suitable catalysts can also be obtained by impregnating silica, clay or aluminum silicates with aqueous solutions of soluble nickel salts, such as nickel nitrate, nickel sulfate or nickel chloride and subsequent calcination.

Catalysts containing nickel oxide are preferred. Catalysts which are essentially composed of NiO, SiO2, TO2 and / or ZrO2 as well as possibly AhO3 are especially preferred. Most preferred is a catalyst containing as essential active constituent parts 10% to 70% by weight of nickel oxide, 5% to 30% by weight of titanium dioxide and / or zirconium dioxide, from 0% to 20 % by weight of aluminum oxide and as a remainder silicon dioxide. Such a catalyst can be obtained by precipitating the catalyst mass at pH 5 to 9 by adding an aqueous solution containing nickel nitrate to an alkaline soluble glass solution containing titanium dioxide and / or zirconium dioxide, filtration, drying and annealing at 350 ° C to 650 ° C. For the preparation of these catalysts, reference is made in particular to document DE-43 39 713. The disclosure of this document and the state of the art cited therein refers in its entirety.

In another embodiment, a catalyst of nickel according to DE-A-199 57 173 is used as a catalyst in step b). In this respect it is essentially aluminum oxide which is charged with a compound of nickel and a sulfur compound. Preferably, in the finished catalyst there is a molar ratio of sulfur with respect to that in the range of 0.25: 1 to 0.38: 1.

The catalyst is preferably in the form of a piece, for example in the form of tablets, for example with a diameter of 2 to 6 mm and a height of 3 to 5 mm, rings with for example 5 to 7 mm of outside diameter, 2 to 5 mm high and 2 to 3 mm in diameter of the opening, or bars of different lengths of a diameter of for example 1.5 to 5 mm. Forms of this type are obtained in a manner known per se by tablet preparation or extrusion, in most cases using a tablet preparation aid, such as graphite or stearic acid.

Preferably, in step b) a mixture of C4 hydrocarbons is used for oligomerization and an oligomerization product is obtained containing from 1% to 25% by weight, preferably from 2% to 20% by weight, especially from 3% to 15%. % by weight of C16 olefins, with respect to the total weight of the oligomerization product.

Stage c) Distillation

From the reaction discharge of the oligomerization reaction, a C16 olefin fraction is isolated in one or more separation steps. Distillative separation of the oligomerization product obtained in step b) with

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obtaining a flow of olefin enriched in C16 olefins can be carried out in this regard continuously or in batches (discontinuously).

Suitable distillation devices are the usual devices known to the expert. This includes, for example, distillation columns, such as plate columns, which, if desired, can be equipped with modules, valves, side discharges, etc., evaporators, such as thin film evaporators, falling film evaporators, renewed film evaporators , Sambay evaporator etc. and combinations thereof. The isolation of the C16 olefin fraction is preferably carried out by fractional distillation.

The distillation itself can be carried out in one or several distillation columns coupled to each other.

The distillation column used or the distillation columns may be carried out in an embodiment in known manner (see for example Sattler, Thermische Trennverfahren, 2nd edition 1995, Weinheim, page 135 and following; Perry's Chemical Engineers Handbook, 7th edition 1997, New York, section 13). The distillation columns used may contain separating action modules, such as separating plates, for example perforated plates, bubble plates or valve plates, ordered packages, for example sheet or fabric packages, or irregular stacking of filling bodies. In the case of the use of plate columns with discharge wells, the residence time of the well preferably increases to at least 5 seconds, especially preferably at least 7 seconds. The specific design and operation data, such as the number of stages required in the column (s) used and the rate of return can be determined by an expert according to known procedures.

In a preferred embodiment, a combination of two columns is used for distillation. In this case, olefin oligomers with less than 16 carbon atoms are extracted (that is, in case of the use of a mixture of C4 hydrocarbons, oligomers C8 and C12) as the head product of the first column. The flow of olefins enriched with C16 olefins is produced as the head product of the second column. Olefin oligomers with more than 16 carbon atoms (that is, in the case of the use of a mixture of C4 hydrocarbons, oligomers C20, C24 and higher) are produced as the background product of the second column.

As evaporators and condensers, suitable types of apparatus are also suitable. As the evaporator, a conventional vessel that can be heated for this purpose or an evaporator with forced circulation can be used, for example a falling film evaporator. If two distillation columns are used for distillation, then they can be equipped with the same or different evaporators and condensers.

Preferably, the background temperatures that occur in the distillation amount to a maximum of 300 ° C, especially preferably at a maximum of 250 ° C. For the maintenance of these maximum temperatures, distillation can be carried out if desired at a suitable vacuum.

Preferably, in step c) a flow of olefins enriched in C16 olefins, which has an olefin content with 16 carbon atoms of at least 95% by weight, particularly preferably at least 98% by weight, is preferably isolated. at least 99% by weight, with respect to the total weight of the olefin flow enriched with C16 olefins. Especially in step c) a flow of olefins enriched in C16 olefins, which is composed essentially (i.e. in more than 99.5% by weight) of olefins with 16 carbon atoms, is isolated.

Stage d) Hydroformylation

For the preparation of a mixture of alcohols the flow of olefins enriched in C16 olefins is hydroformylated and then hydrogenated to give C17 alcohols. In this regard, the preparation of the alcohol mixture can be carried out in a single stage or in two separate reaction stages. A summary of suitable hydroformylation procedures and catalysts is found in Beller et al., Journal of Molecular Catalysis A 104 (1995), p. 17-85.

It is critical for the synthesis of the alcohol mixture described that hydroformylation is carried out in the presence of a cobalt hydroformylation catalyst. According to this in general, the amount of the hydroformylation catalyst amounts to 0.001% to 0.5% by weight, calculated as cobalt metal, with respect to the amount of the olefins to be hydroformylated.

The reaction temperature is generally in the range of about 100 ° C to 250 ° C, preferably 150 ° C to 210 ° C. The reaction can be carried out at an elevated pressure of about 1,000 kPa at 65,000 kPa, preferably 2,500 kPa at 35,000 kPa.

In a suitable embodiment, hydroformylation is carried out in the presence of water; However, this can also be done in the absence of water.

Carbon monoxide and hydrogen are usually used in the form of a mixture, the so-called synthesis gas. The composition of synthetic gas used can be varied in wide ranges. The molar ratio of carbon monoxide and hydrogen generally amounts to about 2.5: 1 to 1: 2.5. A preferred proportion is

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found at approximately 1: 1.

The active cobalt catalyst for hydroformylation is HCo (CO) 4. The catalyst can be preformed outside the hydroformylation reactor, for example from a cobalt salt (II) in the presence of synthesis gas and can be introduced together with the C16 olefins and the synthesis gas into the hydroformylation reactor. Alternatively, the formation of the catalytically active species can be carried out from catalyst precursors only in the hydroformylation conditions, that is to say in the reaction zone. Suitable catalyst precursors are cobalt (II) salts, such as cobalt (II) carboxylates, for example cobalt (II) formate or cobalt (II) acetate; as well as cobalt (II) acetylacetonate or Co2 (CO) 8.

The cobalt catalyst dissolved in a homogeneous manner in the reaction medium can be separated from the hydroformylation product in a suitable manner, the hydroformylation reaction discharge being treated first in the presence of an aqueous acid solution with oxygen or air. In this regard, the cobalt catalyst with formation of cobalt salts (II) is oxidatively destroyed. Cobalt (II) salts are soluble in water and can be separated by extracting the reaction discharge with water. These can generally be used again for the preparation of a hydroformylation catalyst and can be redirected to the hydroformylation process.

For the continuous realization of hydroformylation, it is possible, for example, to proceed so that (i) an aqueous solution of cobalt salt (II) is brought into close contact with hydrogen and carbon monoxide with the formation of an active cobalt catalyst for hydroformylation; (ii) the aqueous phase containing the cobalt catalyst is brought into close contact in a reaction zone with the olefins as well as hydrogen and carbon monoxide, the cobalt catalyst being extracted in the organic phase and the olefins hydroformylated; and (iii) the discharge from the reaction zone is treated with oxygen, the cobalt catalyst decomposing with cobalt (II) salt formation, the cobalt (II) salts are extracted again in the aqueous phase and the phases The aqueous solution of cobalt (II) salt is then redirected to the process. Suitable cobalt (II) salts are, in particular, cobalt (II) acetate, cobalt (II) formate and cobalt (II) ethylhexanoate. Advantageously, the formation of the cobalt catalyst, the extraction of the cobalt catalyst in the organic phase and the hydroformylation of the olefins in one step can be carried out, the aqueous solution of cobalt salt (II), the olefins and, eventually, being brought into close contact. organic solvent as well as hydrogen and carbon monoxide in the reaction zone under hydroformylation conditions, for example by means of a mixing nozzle.

The crude aldehydes or mixtures of aldehydes / alcohols obtained during hydroformylation can be isolated before hydrogenation if desired according to usual procedures, known to the expert and can eventually be purified. As a general rule, the mixture of products obtained after separation of the hydroformylation catalyst can be used without further processing in the hydrogenation.

Hydrogenation

For the hydrogenation, the reaction mixtures obtained during the hydroformylation with hydrogen are reacted in the presence of a hydrogenation catalyst.

Suitable hydrogenation catalysts are generally transition metals, such as, for example, Cr, Mo, W, Fe, Rh, Co, Ni, Pd, Pt, Ru etc. or their mixtures, which can be applied on supports to increase activity and stability, such as for example active carbon, aluminum oxide, diatomaceous earth etc. To increase the catalytic activity, Fe, Co and preferably Ni can also be used, also in the form of Raney catalysts as a metal sponge with a very large surface. Preferably, a Co / Mo catalyst is used for the preparation of the surfactant alcohols according to the invention. The hydrogenation of the oxo-aldehydes is carried out depending on the activity of the catalyst preferably at elevated temperatures and elevated pressure. Preferably the hydrogenation temperature is found at about 80 ° C to 250 ° C. Preferably the pressure is found at approximately 5,000 kPa to 35,000 kPa.

From the reaction mixture obtained after hydrogenation, it can be processed according to usual purification procedures, known to the expert, in particular by fractional distillation, a mixture of C17 alcohols having the degree of branching described above being obtained purely.

The mixture of C17 alcohols obtained according to the described process preferably has an alcohol content with 17 carbon atoms of at least 95% by weight, especially preferably at least 98% by weight, in particular at least 99% by weight. weight, with respect to the total weight of the C17 alcohol mixture. Especially it is a mixture of C17 alcohols which is essentially composed (that is to say in more than 99.5% by weight, especially in more than 99.9% by weight) of alcohols with 17 carbon atoms.

R1-X Surfactants

In the case of the hydrophilic groups X of the surfactant R1-X it may be anionic, non-ionic, cationic or betarnic groups. Preferably it is anionic or non-ionic groups. Examples of preferred X groups include sulfonate groups, polyoxyalkylene groups, anionically modified polyoxyalkylene groups, glucoside groups or amine oxide groups. Especially preferred are surfactants with polyoxyalkylene groups asf

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as anionically modified polyoxyalkylene groups. The anionically modified polyoxyalkylene groups preferably have terminal sulfonate groups, terminal carboxylate groups or terminal sulfate groups. The polyoxyalkylene groups may comprise 1 to 50 oxyalkylene groups, preferably 1 to 40, preferably ethoxy groups and / or propoxyl groups. In addition, even higher alkyleneoxy groups may also be present. Preferably, in the case of at least 50% of the oxyalkylene groups present it is ethoxy groups. R1-X surfactants of this type can be prepared starting from R1-OH alcohols according to procedures known in principle by the expert. In the case of group X it can also be OH, that is to say R1-OH alcohol itself must also be considered as a surfactant within the meaning of this invention.

Description of preferred R1-X surfactants

Preferred R1-X surfactants for use in the extraction of tertiary oil are described below.

In a preferred embodiment of the invention, in the case of the surfactants according to the invention, they are those selected from the group of alkylalkoxylates (A), alkylene ether sulphonates (B), alkylene ether carboxylates (C), alkylene ether sulfates (D), alkyl -polyglucosides (E) and / or alkylamine oxides (F).

Alkylalkoxylates (A)

Alkylalkoxylates (A) have the general formula (I)

R1O- (CH2CH (R2) O) n (CH2CH2O) m-H (I).

Alkylalkoxylates (A) comprise n alkoxy groups of the general formula -CH2CH (R2) O- as well as m ethoxy groups -CH2CH2O-. In this regard, the alkoxyl group formula must also include units of the formula -CH (R2) CH2O- together, that is to say alkoxy groups incorporated in reverse orientation in the surfactant, both arrangements being also logically represented in a surfactant molecule. In the case of R2, they are straight chain, branched, aliphatic or aromatic hydrocarbon moieties with 1 to 10 carbon atoms, and several different R2 moieties may also have a surfactant molecule. Preferably, in the case of R2 it is a methyl, ethyl, n-propyl and / or phenyl group and especially preferably a methyl group, that is to say in the case of the alkoxy group it is a propoxyl group.

The numbers n and m refer in this respect in a known manner to the average value of the alkoxy or ethoxy groups existing in the surfactant, the average value logically should not be a natural number, but may also be any rational number. According to this, the number n represents values from 0 to 15, preferably from 0 to 7, and especially preferably from 0 to 5, and m represents values from 1 to 20, preferably from 2 to 15, and especially preferably from 5 to 14. According to this, the sum k = n + m represents a value from 1 to 35, preferably from 2 to 20 and especially preferably from 5 to 15. Also preferably it is m> n, that is, in the variant it is preferably the number of ethoxy groups larger than alkoxy groups.

The arrangement of the alkoxy groups and ethoxy groups in the surfactant (I), provided that both types of groups are present, can be statistic or alternate, or there may be a block structure. Preferably it is a block structure, in which the alkoxy and ethoxy groups are actually arranged in the order R 1 O-alkoxy block-ethoxy-H block.

The alkylalkoxylates (A) can be prepared in principle in a known manner by alkoxylation of the alcohol R1-OH. The realization of alkoxylations is known in principle by the expert. The expert also knows that through the reaction conditions, in particular the choice of the catalyst, the molecular weight distribution of the alkoxylates can be influenced.

Alkylalkoxylates (A) can be prepared, for example, by base catalyzed alkoxylation. For this, the R1-OH alcohol can be mixed in a pressure reactor with alkali metal hydroxides, preferably potassium hydroxide or with alkali metal alcoholates such as for example sodium methylate. By reducing pressure (for example <10 kPa) and / or increasing the temperature (from 30 ° C to 150 ° C), existing water can be removed even in the mixture. The alcohol is found later as the corresponding alcoholate. It is then inerted with inert gas (for example nitrogen) and the alkylene oxide (s) are gradually added at temperatures of 60 ° C to 180 ° C until a pressure of at most 1000 kPa. At the end of the reaction the catalyst can be neutralized by the addition of acid (for example acetic acid or phosphoric acid) and can be separated by filtration if necessary. Alkylalkoxylates prepared by means of catalysis with KOH generally have a relatively wide molecular weight distribution.

In a preferred embodiment of the invention, the alkylalkoxylates (A) are synthesized by means of techniques known to the expert, which lead to narrower molecular weight distributions than in the base catalyzed synthesis. For this purpose, for example, double hydroxide clay can be used as catalyst, as described in DE 43 25 237 A1. Alkoxylation can be carried out especially preferably using double metal cyanide catalysts (DMC catalysts). Suitable DMC catalysts are disclosed for example in DE 102 43 361 A1, in particular paragraphs [0029] to [0041] as well as the

bibliography cited therein. For example, catalysts of the Zn-Co type can be used. To carry out the reaction, R1-OH alcohol can be mixed with the catalyst, the mixture can be dehydrated as described above and reacted with the alkylene oxides as described. Usually no more than 250 ppm of catalyst are used with respect to the mixture, and the catalyst can remain in the product 5 due to this low amount. The surfactants according to the invention prepared by means of DMC catalysis are characterized in that they have as a consequence a better reduction of the surface surface limit in the water-oil system than the products prepared by means of catalysis with KOH.

The alkylalkoxylates (A) can also be prepared by acid catalyzed alkoxylation. In the case of acids, it may be Bronstedt or Lewis acids.

10 To carry out the reaction, R1-OH alcohol can be mixed with the catalyst, the mixture can be dehydrated as described above and reacted with the alkylene oxides as described. At the end of the reaction the catalyst can be neutralized by adding a base, for example KOH or NaOH and can be filtered off if necessary. With the choice of the catalyst, the structure of the hydrophilic group X can be influenced. While, during the basic catalysis, the alkoxy units are predominantly incorporated into the orientation reproduced in the formula (la) in the alkylalkoxylate, during the acid catalysis they incorporate the units mostly in the orientation (Ib).

image2

Alkyl ether sulfonates (B)

The alkylene ether sulphonates (B) are derived from the alkylalkoxylates (A) and additionally have a terminal sulfonate group. The alkylene ether sulfonates (B) have the general formula (Il)

R1O- (CH2CH (R2) O) n (CH2CH2O) m-R3-SO3M (II),

in which R2 has the meaning defined above. In formula (II) M represents H + or a k-valent counterion 1 / xYx +. x represents according to this the charge of the counterion. Preferably it is a monovalent counterion, such as NH4 + -, ammonium ions with organic moieties or alkali metal ions. Preferably Y represents Li +, Na + and 25 K +, and especially preferably it is Na +. The alkylene ether sulfonate can therefore be found as acid

free or as a salt thereof.

The number n 'according to this represents values from 0 to 15, preferably from 1 to 10 and m' represents values from 1 to 20, preferably from 2 to 15 and especially preferably from 5 to 14. The sum k '= n' + m 'according to this represents a value from 1 to 35, preferably from 1 to 20 and especially preferably from 1 to 15. Also 30 is preferably m'> n ', that is, the number of ethoxy groups is greater than the number of alkoxy groups.

As defined above, it may be the arrangement of the statistical or alternating alkoxy and ethoxy groups, or there may be a block structure. It is preferably a block structure, in which the alkoxy and propoxy groups are actually arranged in the order R 1 O-alkoxy block-ethoxy block-R 3 -SO 3M.

In the case of the R3 group, which links the alkoxy group with the sulfonate group, it is a divalent hydrocarbon group with 2 to 12 carbon atoms, preferably 2 to 4 carbon atoms, which may optionally have functional groups such as substituents Preferably it is a group selected from the group of 1,2-ethylene groups -CH2-CH2-, 1,2-propylene groups -CH2-CHR2- or -CH (R2) -CH2- or 1,3-propylene groups - CH2- CH (R4) -CH2-, R2 having the meaning defined above and representing R4 H or OH.

The alkylene ether sulfonates (B) according to the invention can be prepared using the alkylalkoxylates (A) as starting material. The sulphonate transformation can be carried out, for example, by substituting the OH group of the alkoxylate for Cl using phosgene or thionyl chloride. The reaction can be carried out in the presence of a solvent, such as for example chlorobenzene. In this regard, the HCl that is released as well as the CO2 or SO2 that is released can be advantageously separated from the system by stabilizing distillation with nitrogen, so that a dissociation of the ether is prevented. The alkylalkoxychloro compound is then reacted with an aqueous solution of sodium sulfite, the chloride being replaced by sulphite and the alkylene ether sulfonate is obtained. The substitution can be carried out in the presence of a phase compatibilizer (for example C1 to C8 alcohols) at a temperature of 100-180 ° C and under pressure. Depending on whether in the alkylalkoxylate (A) an ethoxy group or an alkoxy group is present as a terminal group, the alkylene ether sulfonate (B) present as a terminal -R-SO3M group a group -CH2CH2-SO3M or -CH (R2) -CH2- SO3M or -CH2-CH (R2) -SO3M. In this variant of synthesis, k '= k-1 is applied. An alternative to chlorination is the sulfation of alkylalkoxylates (A) with SO3 in a downstream film reactor and subsequent neutralization with NaOH. The alkylene ether sulfate formed by nucleophilic substitution

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of the sulfate group by means of sodium sulphite is transformed analogously to the above description in the alkylene ether sulfonate (B).

The alkylene ether sulphonates (B) can be obtained as an alternative by adding vinyl sulfonic acid to the alkylalkoxylate (A). Particularities in this regard have been described, for example, in EP 311 961 A1. In this case, an alkylene ether sulfonate (B) with a terminal group -CH2CH2-SO3M is obtained, applying k '= k.

The alkylene ether sulfonates (B) with a terminal group -CH2-CH2-CH2-SO3M (ie R4 = H) can be obtained by reacting the alkylalkoxylate with 1,3-propanesulfone. Alkyl ether sulphinates (B) with a terminal group - CH2-CH (OH) -CH2-SO3M are accessible by reacting the corresponding alkylalkoxylate (A) with epichlorohydrin and subsequent nucleophilic substitution of the chloride group by sodium sulphite. In both cases, k '= k applies.

Alkylethercarboxylates (C)

Alkylethercarboxylates (C) are derived from alkylalkoxylates (A) and additionally have a terminal carboxylate group. Preferred alkylethercarboxylates (C) have the general formula (III)

R1O- (CH2CH (R2) O) n "(CH2CH2O) m" -R5-COOM (III),

in which R2 and M have the meaning defined above.

The number n "according to this represents values from 0 to 15, preferably from 1 to 10 and m" represents values from 1 to 20, preferably from 2 to 15 and especially preferably from 5 to 14. The sum k "= n" + m "according to this represents a value from 1 to 35, preferably from 1 to 20 and especially preferably from 1 to 15. Also preferably it is m"> n ", ie the number of ethoxy groups is greater than the number of groups alkoxy

The alkylethercarboxylate (C) can therefore be found as a free acid or as a salt thereof. As defined above, it may be the arrangement of the statistical or alternating alkoxy and ethoxy groups, or there may be a block structure. Preferably it is a block structure, in which the alkoxy and propoxy groups are actually arranged in the order R 1 O-alkoxy block-ethoxy block-R 5 -COOM.

In the case of the R5 group, which links the alkoxy group with the carboxylate group, it is a divalent hydrocarbon group with 1 to 12 carbon atoms, preferably 1 to 3 carbon atoms. Preferably it is a methylene group -CH2-, a 1,2-ethylene group -CH2-CH2- or a 1,2-propylene group -CH2-CH (CH3) -.

The alkylethercarboxylates (C) according to the invention can be prepared using the alkylalkoxylates (A) as the starting material. These can be converted by oxidation of the alkoxylate into the corresponding alkylene ether carboxylates (C). To this end, all oxidation agents are suitable, possibly in conjunction with suitable catalysts, which can oxidize the terminal OH group of the alkylalkoxylate (A) to give the COOH group, without greatly oxidizing other parts of the molecule. The oxidation can be carried out, for example, with the aid of air or oxygen using a noble metal catalyst (for example a palladium-based catalyst). In this variant of synthesis a terminal group -CH2-COOM is obtained and k '= k -1 is applied.

In another embodiment of the invention, the alkylene ether carboxylates (C) according to the invention can also be prepared by adding to an alkylalkoxylate (A) by means of an addition of Michael (meth) acrylic acid or an ester of (meth) acrylic acid. In the case that the esters are used, these are saponified after the addition. In these variants of synthesis, depending on whether acrylic acid or (meth) acrylic acid or its esters are used, terminal groups -CH2-CH2-COOM or -CH2-CH (CH3) -COOM and apply k "= k .

Alkyl ether sulfates (D)

Alkyl ether sulfates (D) are derived from alkylalkoxylates (A) and additionally have a terminal sulfate group. The alkylene ether sulfates (D) have the general formula (IV)

R1O- (CH2CH (R2) O) n "(CH2CH2O) m" -SO3M (IV),

in which R2 has the meaning defined above. In formula (IV), M represents H + or a k-valent counterion 1 / xYx +. According to this, x represents the charge of the counterion. Preferably it is a monovalent counterion, such as NH4 + -, ammonium ions with organic moieties or alkali metal ions. Preferably Y represents Li +, Na + and K +, and especially preferably it is Na +. The alkylene ether sulfate can therefore be found as free acid or as a salt thereof.

The number n '"according to this represents values from 0 to 15, preferably from 1 to 10 and m'" represents values from 1 to 20, preferably from 2 to 15 and especially preferably from 5 to 14. The sum k "' = n '"+ m'" as this represents a value from 1 to 35, preferably from 1 to 20 and especially preferably from 1 to 15. Also preferably it is m "'> n"', that is, the number of ethoxy groups is greater than the number of alkoxy groups.

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As defined above, it may be the arrangement of the statistical or alternating alkoxy and ethoxy groups, or there may be a block structure. Preferably it is a block structure, in which the alkoxy and propoxy groups are actually arranged in the order R 1 O-alkoxy block-ethoxy-sO 3 M block.

The alkylene ether sulfates (D) according to the invention can be prepared using the alkylalkoxylates (A) as the starting material. The sulfate transformation can be carried out, for example, by adding the OH group of the alkoxylate to sulfur trioxide and subsequently neutralizing with, for example, sodium hydroxide solution. This can be done, for example, in a falling film reactor.

Alkyl Polyglucosides (E)

The alkyl polyglucosides (E) have as a terminal group a polyglucoside group. Preferred alkyl polyglucosides (E) have the following formula (V)

image3

According to this, I represents a number from 0 to 2, in the case of I being the average value of the distribution. The alkyl polyglucosides (E) can be prepared in a known principle, transforming glucose with the aid of an acid catalyst, such as, for example, para-toluenesulfonic acid and n-butanol in the corresponding butylacetal. The reaction water produced can be removed by application of the reaction mixture ford. The alcohol R1-OH is then added and the retaliation is promoted by distillation of butanol from equilibrium. The acid catalyst can be neutralized at the end of the reaction by adding base, for example NaOH or KOH.

Alkylamine Oxides (F)

Alkylamine oxides (F) have the general formula (VI)

image4

In the case of R6 or R7, they are independently treated with methyl or hydroxyethyl radicals. The amine oxides (F) can be prepared in a known principle, by transforming the alcohol R1-OH or its precursor, the aldehyde, into a catalytic reductive amination with N, N-dimethylamine or diethanolamine and hydrogen in the corresponding tertiary amine. The amine oxide can be obtained from this below by adding hydrogen peroxide.

Use for tertiary oil extraction

The R1-X surfactants according to the invention can preferably be used for tertiary oil extraction (EOR). These cause, by a strong reduction in the surface tension limit between oil and water, an especially good mobilization of crude oil in the formation of oil.

These are introduced by pressing for it in the form of a suitable formulation for at least one injection perforation in the oil field, and crude oil is extracted from the field for at least one production hole. The term "crude oil" means in this context logically not only oil free of phase displacement, but also that the term jointly includes the usual emulsions of crude oil-water. As a general rule a deposit of several perforations of injection and several production perforations Following the introduction by means of pressure of the surfactant formulation, the so-called "surfactant thrust" can be injected for the maintenance of the water pressure in the formation ("water thrust") or preferably an aqueous solution of higher viscosity of a polymer of very thickening action ("push by polymer"). However, techniques are also known, according to which the surfactants are allowed to act first once on the formation. The expert knows particularities regarding the technical realization of "push by surfactant", "push by water" and "push by polymer" and this applies a corresponding technique depending on the type of reservoir.

The surfactants according to the invention are used according to this preferably in aqueous formulation. In addition to water, the formulations may optionally contain as solvent no more than 50% by weight,

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preferably not more than 20% by weight of alcohols miscible with water.

For the extraction of tertiary oil, only a single surfactant of the R1-X surfactants according to the invention can be used respectively. However, preferably a formulation comprising at least two different surfactants is used, in the case of at least one of them being a R1-X surfactant.

The R1-X surfactant can be used according to this as a surfactant or also as a co-surfactant. By "surfactant", also referred to as "secondary surfactant", in principle known is a surfactant that is added in low quantity to other surfactants or mixtures of surfactants to improve their property profile by synergistic action. The amount of all R1-X surfactants together with respect to the total amount of all surfactants used in a mixture of surfactants is determined by the expert depending on the type of properties desired. The amount of R1-X surfactants in the general case amounts to 1% to 99% by weight, with respect to the total amount of all surfactants in the mixture. Preferably, the amount amounts to 10% to 95% by weight.

Examples of other surfactants, which may be used in addition to the R1-X surfactants, comprise anionic surfactants, in particular organic sulphonates, such as for example olefinsulfonates or alkylarylsulfonates, nonionic surfactants or anionic surfactants, which are prepared by anionic modification of nonionic surfactants , such as, for example, ether sulfates, ether sulphonates or ether carboxylates or alkyl polyols and / or alkyl polyglucosides. In addition, amine oxides, surfactants with ammonium groups or betarnas can also be used.

In addition to the surfactants, the formulations may also contain other components such as Ci to C8 alcohols and / or basic salts (the so-called "alkali surfactant flooding"). With additions of this type, for example, retention in formation can be reduced.

Preferred mixtures for the extraction of tertiary oil, which comprise R1-X surfactants, are described below.

In a preferred embodiment of the invention, a mixture (M) of at least one non-ionic surfactant (Mi) and at least one anionic surfactant (M2) can be used for tertiary extraction of oil, in the case of at least one of the two surfactants of an R1-X surfactant. In the case of the anionic surfactant (M2) it is especially preferably an anionically modified nonionic surfactant, in particular a modified surfactant with sulphonate groups and / or carboxylate groups and / or sulfate groups. Mixtures of this type are especially suitable for use in highly saline deposits. Mixtures may be formulated for use, as described above, preferably with suitable solvents or solvent mixtures.

In addition, mixtures of at least one surfactant that behaves in a non-ionic manner (Mi ') as well as at least one surfactant that behaves ionically (M2') are preferred. This is why surfactants are to be understood respectively, in which group X comprises both ionic and non-ionic structural units, and in which a non-ionic or an ionic behavior dominates depending on the type and / or conditions of use. Examples of surfactants of this type include the alkylene ether sulphonates, alkylene ether carboxylates and alkylene ether sulfates mentioned above. A typical non-ionic surfactant with polyether units behaves in a more hydrophobic oil-water-surfactant system with increasing temperature. Surfactants of this type form, at lower temperatures, first an oil in water emulsion, that is an oil emulsion in a continuous aqueous phase. With increasing temperature, a phase transition finally takes place to give a water-in-oil emulsion, that is, a water emulsion in a continuous oil phase. This transition can be followed, for example, by a measurement of conductivity. The transition of a continuous aqueous phase into a discontinuous aqueous phase is associated with a clear brown of conductivity. Surfactants that behave ionically behave inversely and become more hydrophilic with increasing temperature. A water-in-oil emulsion is therefore converted to an oil-in-water emulsion with increasing temperature, which can also be followed equally by a conductivity measurement.

Preferably it is a mixture (M) comprising as components at least one alkylalkoxylate (A) and / or an alkylene ether sulfonate (B) and / or alkylene ether sulfate (D). In addition, a mixture is preferred than an alkylene ether sulfonate (B) in admixture with an alkylene ether carboxylate (C), in particular a mixture of an alkyl alkoxylate (A), an alkylene ether sulfonate (B) and an alkylene ether carboxylate (C).

As the mixing component in addition to the surfactants according to the invention, surfactants of the general formula R8-X are especially suitable, in which in the case of R8 it is an aliphatic or araliphatic Ci6 to C20 hydrocarbon residue, preferably a residue of Cia to Ci8 hydrocarbon. A preferred moiety should have a degree of branching of less than 2, preferably less than 1, and especially preferably should be linear. In the case of hydrocarbon moieties, for example, they may be 4-dodecylphenyl moieties, or hexadecyl, heptadecyl or octadecyl moieties. In the case of residue X it is a hydrophilic group as defined above, preferably a residue X selected from the group of sulfonate groups, polyoxyalkylene groups, anionically modified polyoxyalkylene groups, glucoside groups or amine oxide groups.

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Particularly preferably, in the case of R8-X surfactants, it may be alkylalkoxylates of the general formula

R8- (CH2CH (R2) O) n (CH2CH2O) m-H (VII),

in which the indexes have the previous meaning. In addition, it may preferably be alkylether sulphonates of the general formula

R8O- (CH2CH (R2) O) n- (CH2CH2O) m-R3-SOaM (VIII),

in which the indices also have the previous meaning. Mixtures of the surfactants R1-X and R8-X can be prepared in a particularly simple manner, starting with the alkoxylation of a mixture of alcohols R1-OH and R8-OH and using the mixture of these alcohols as described above.

In another preferred embodiment, it comprises the mixture (M) in addition to the components (M1) and (M2) even a polymeric co-surfactant (M3). The amount of the co-surfactant (M3) amounts to no more than 49.9% by weight, based on the total amount of all the surfactants (M1), (M2) and (M3) used. Preferably, the amount is from 1% to 10% by weight. With the polymeric co-surfactants of this type, the amount of surfactant necessary for the formation of a microemulsion can be advantageously reduced. Polymeric co-surfactants of this type are therefore also designated as "microemulsion enhancer".

In the case of polymeric co-surfactants (M3) these are amphiphilic block copolymers, which comprise at least one hydrophilic block and at least one hydrophobic block. These preferably have Mn molecular masses of 1000 g / mol to 50,000 g / mol. In this case, the hydrophilic blocks and the hydrophobic blocks should have at least a molar mass of respectively 500 g / mol, preferably 750 g / mol and especially preferably 1000 g / mol. The hydrophobic and hydrophilic blocks can be linked together according to this in a different way. It can be, for example, two-block co-polymers or multi-block co-polymers, in which the hydrophobic and hydrophilic blocks are arranged alternately. The polymers can be linear, branched or star-shaped or it can also be a comb polymer, which has a main chain as well as one or several side chains linked thereto.

Block copolymers having hydrophilic blocks of poly (ethylene oxide) blocks or statistic blocks of poly (ethylene oxide) -poly (propylene oxide) are preferred, and the proportion of propylene oxide must not exceed 40 mol% , preferably 20% by mole and especially preferably 10% by mole with respect to the sum of the ethylene oxide and propylene oxide units introduced by polymerization in the block. Preferably these are pure blocks of poly (ethylene oxide). In the case of hydrophobic blocks, it can be, for example, blocks of poly (propylene oxide) or C4 to C12 alkylene oxides. In addition, the hydrophobic blocks may be constituted, for example, by hydrocarbon units or esters of (meth) acrylic acid.

Preferred polymeric co-surfactants (M3) comprise block copolymers of poly (propylene oxide) - poly (ethylene oxide), block copolymers of polyisobutene-poly (ethylene oxide) as well as comb polymers with poly side chains (ethylene oxide) and a hydrophobic main chain, the main chain preferably comprising essentially olefins or (meth) acrylates as structural units. According to this, the term "poly (ethylene oxide)" must include, respectively, poly (ethylene oxide) blocks comprising propylene oxide units according to the above definition. More detailed particularities with respect to the preferred polymeric surfactants (M3) are disclosed in WO 2006/131541.

The following examples will explain the invention in more detail:

I) Preparation of starting materials

Example A: preparation of an aliphatic, branched C17 R1-OH alcohol with a branching grade of 3.1 Oligomerization of olefins:

In an isothermally operated reactor of a length of approximately 1.5 m and a diameter of 30 mm, it was reacted at 2,000 kPa and 80 ° C refined from the following composition in a heterogeneous catalyst.

i-Butane:

n-Butane:

i-Butene:

Butene-1:

Butene-2-trans:

Butene-2-cis:

3% by weight 15% by weight 2% by weight 30% by weight 32% by weight 18% by weight

A catalyst served as a material, which had been prepared in accordance with DE-A-43 39 713 in the form of tablets (5 mm x 5 mm). The composition in% by weight of the active components was: 50% by weight of

NiO, 12.5% by weight of TiO2, 33.5% by weight of SiO2, 4% by weight of AI2O3. The yield amounts to 0.75 kg of refining II / (I (cat) x h). Work without reconduction of C4 hydrocarbons. The conversion of C4, with respect to the butenes contained in the refined II, amounted to 52.0% by weight.

The selectivity in% by weight was as follows: C8: 76.9; C12: 18.4 and C16 +: 4.7.

5 Distillation of the C16 + mixture:

The crude C16 + mixture is distilled in a technical distillation installation consisting of two columns with in each case approximately 15 m of packing height (250 m / m). In this regard, low boiling compounds (especially C12 olefins) contained in the first column (head fraction column) were taken out of the head. In the second column (main fraction column) the C16 olefin with a purity of> 99% was removed from the head, while the C20 + olefins were separated in the background.

The two columns were operated with the following parameters:

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 Head temperature

 Head fraction column 135 ° C Main column 165 ° C fraction

 Background temperature

 180-182 ° C 225 - 230 ° C

 Pressure (head)

 8.5 kPa 6.0 kPa

 Loss of pressure through packing

 approx. 0.5 kPa approx. 5.0 kPa

 Feeding

 2700 kg / h 2500 kg / h

 Head extraction

 200 kg / h 1700 kg / h

 Return

 850 kg / h 3000 kg / h

 Background

 2500 kg / h 800 kg / h

 Hydroformylation:

 The hydroformylation facility described in EP 1204624 was continuously fed with 2.2 t / h of C16 olefin and 0.2 t / h of an aqueous solution of cobalt salt. In this regard the following conditions were adjusted in the reactor:

 Cobalt concentration 0.10% by weight Temperature 185 ° C Pressure (CO / H2 approx. 1: 1) 28,000 kPa

 The discharge of the hydroformylation was deobalt oxidatively, as described in EP 1204624, and then hydrogenized in the hydrogenation installation described in DE 10036172 in the Co / Cu / Mo catalyst there described to give the alcohol. In this regard the following parameters were adjusted:

 Pressure Temperature (H2)

 160 ° C 28,000 kPa

 The crude alcohol thus obtained was purified in the installation conditions to give the pure alcohol.

 distillation described above in the following

 Head temperature

 Fraction column Head column Main fraction 155 ° C 214 ° C

 Background temperature

 222 ° C 235 ° C

 Pressure (head)

 6.0 kPa 6.0 kPa

 Loss of pressure through packing

 2.0 kPa 20 kPa

 Feeding

 2450 kg / h 2000 kg / h

 Head extraction

 450 kg / h 1800 kg / h

 Return

 850 kg / h 900 kg / h

 background

 2000 kg / h 200 kg / h

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Instructions for the determination of the Iso index of the C17 alcohol mixture by means of NMR-1H: approx. 20 mg of C17 alcohol mixture is dissolved in 0.4 ml of CDCh and a small amount of tMs is added to refer to the frequency. The solution is then mixed with 0.2 ml of TAI, introduced into a 5 mm NMR tube and measured in the NMR spectrometer.

Measuring conditions:

Spectrometer frequency: 400 MHZ Relaxation delay: 10 s Pulse angle: 30 °

Data points recorded: 64 K Number of sweeps: 64 Data points transformed 64 K Exponential multiplication: 0.2 Hz

After Fourier transformation, an automatic correction of phases and basic lines a manual integration of the intervals 4.7 to 3.7 ppm (all primary alcohols esterified with TAI) and 2.4 to 0.4 ppm ( all protons of methyl, methylene and methine). In this respect, the zero-order integral phases are selected so that they run essentially horizontally at the beginning and end of the integral curves. Signals <1 ppm are assigned to methyl groups.

The determined Iso asf index amounts to: 3.1

II) Preparation of surfactants

Example 1: Preparation of a non-ionic surfactant (iCi7 alcohol + 10 ethylene oxide by KOH catalysis)

The branched C17H35 alcohol according to example A (250.4 g, 1.019 mol) is mixed with KOH solution (50%, 4.2 g, 0.037 mol) in a 2 l pressure autoclave from Mettler and dehydrates for 3 h at 100 ° C and 1.5 kPa. It is then inertized twice with nitrogen (up to 500 kPa), a prepressure of 100 kPa is adjusted and heated to 130 ° C. In the range of 4.5 hours, a maximum pressure of 700 kPa ethylene oxide (449 g, 10.19 mol) is dosed and after finishing the addition it is subsequently stirred even for 3 hours. Finally the compound is degassed under vacm (1.5 kPa), mixed with Ambosol (3 percent by weight) and filtered. IC-i7-10 OE (final weight 700 g, teona 707 g; OH index 78.2 mg KOH / g, teona 81.8 mg KOH / g) is obtained as clear liquid. The molar mass distribution of the surfactant was determined by means of size exclusion chromatography.

Example 2: Preparation of a non-ionic surfactant (iC17 alcohol + 10 ethylene oxide by DMC catalysis)

The branched C17H35 alcohol according to example A (308.4 g, 1,255 mol) is mixed with DMC catalyst (Zn-Co cyanide complex, 0.86 g) by Ultraturax, transferred to a pressure autoclave of 2 l from the Mettler company and dehydrates for 2 h at 110 ° C and <1.0 kPa. It is then inertized twice with nitrogen (up to 500 kPa), a prepressure of 100 kPa is adjusted and heated to 130 ° C. In the range of 5.2 h it is dosed to a maximum pressure of 700 kPa ethylene oxide (552 g, 12.55 mol) and after finishing the addition it is subsequently stirred even for 4 h.

Finally the product is degassed under vacm (1.5 kPa) and filtered.

IC-i7-10 OE (final weight 857 g, teona 861 g; OH 81.1 mg KOH / g, Teona 81.8 mg KOH / g) is obtained as clear liquid.

The molar mass distribution of the surfactant was determined by means of size exclusion chromatography. The surfactant prepared by catalysis with DMC had a significantly narrower molar mass distribution than the surfactant prepared by catalysis with KOH according to example 3.

Example 3: Preparation of a non-ionic surfactant (iCi7 alcohol + 2 ethylene oxide by DMC catalysis)

The branched C17H35 alcohol according to example A (477.7 g, 1,944 mol) is mixed with DMC catalyst (Zn-Co cyanide complex, 0.65 g) by Ultraturax, transferred to a pressure autoclave of 2 l from the Mettler company and dehydrates for 2 h at 110 ° C and <1.0 kPa. It is then inertized twice with nitrogen (up to 500 kPa), a prepressure of 100 kPa is adjusted and heated to 130 ° C. In the 1.2 h interval, the ethylene oxide (171.1 g, 3.888 mol) is dosed to a maximum pressure of 700 kPa and after finishing the addition it is subsequently stirred for 10 h.

Finally the product is degassed under vacm (1.5 kPa) and filtered. IC-i7-2 OE (final weight 641 g, teona 649 g; OH 171 mg KOH / g, Teona 168.1 mg KOH / g) is obtained as clear liquid.

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Example 4: Preparation of an ionic surfactant (iCi7-2 OE-SO3H alcohol)

1st stage

ICi7-2 OE (98 g, 0.3 mol) of Example 1 is cooled in a 500 ml multi-necked flask with KPG agitator, reflux cooler, gas introduction duct and temperature detector up to 10 ° C and it is mixed dropwise with thionyl chloride (39.2 g, 0.33 mol) at this temperature. After stirring for 1 h at 20 ° C, a flow of N2 is conducted through the solution and slowly heated to 60 ° C. It is then stirred for 3 h at 110 ° C. A volumetric determination of the chloride ion content (with AgNO3) indicated a complete conversion as well as the removal of HCl. The iC-i7-2 OE-Cl structure was confirmed by spectroscopy (IR, NMR-1H).

2nd stage

IC-i7-2 OE-Cl (52.82 g, 0.15 mol) is mixed in a 300 ml autoclave with iPrOH (25 g), sodium sulphite (20.8 g, 0.165 mol), distilled water ( 78 g) and sodium hydroxide solution (50%, 0.75 g). After washing with N2 it is heated at 500 revolutions per min to 160 ° C, stirred for 30 h at this temperature and cooled again to room temperature. A volumetric determination of the chloride ion content (with AgNO3) indicated a complete conversion. It is then released from the solvent. IC-i7 - 2 OE - SO3H is obtained

Comparative example 1: non-ionic surfactant based on an arylalkyl alcohol (dodecylphenol + 10 OE by catalysis with KOH)

4-Dodecylphenol (209.4 g, 0.798 mol; Aldrich) is mixed with KOH solution (50%, 3.36 g, 0.03 mol) in a pressure autoclave of 2 l from the company Labmax and dehydrated for 2 h at 100 ° C and 1.5 kPa. It is then inertized twice with nitrogen (up to 500 kPa), a prepressure of 100 kPa is adjusted and heated to 130 ° C. In the 3-hour interval, a maximum pressure of 700 kPa ethylene oxide (351 g, 7.98 mol) is dosed and after finishing the addition, it is subsequently stirred even for 5 h.

Finally the compound is degassed under vacuum (1.5 kPa), mixed with Ambosol (3 percent by weight) and filtered. Dodecylphenol -10 OE (final weight 560 g, teona 561.6 g; OH index 82.8 mg KOH / g, theone 79.9 mg KOH / g) is obtained as a transparent liquid.

Comparative example 2: non-ionic surfactant based on an arylalkyl alcohol (dodecylphenol + 13 OE by catalysis with KOH)

We proceeded as in comparative example 1, only one degree of ethoxylation of 13 was adjusted.

Comparative example 3: non-ionic surfactant based on a linear alcohol (C16-C18 + 10 OE fatty alcohol by KOH catalysis)

C16-C18 fatty alcohol (403 g, 1,586 mol) is mixed with KOH solution (50%, 6.6 g, 0.057 mol) in a pressure autoclave of 2 l and dehydrated for 2 h at 95 ° C and 1, 5 kPa It is then inertized twice with nitrogen (up to 500 kPa), a prepressure of 100 kPa is adjusted and heated to 130 ° C. In the 3-hour interval, a maximum pressure of 800 kPa ethylene oxide (698 g, 15.86 mol) is dosed and after finishing the addition, it is subsequently stirred for 5 h.

Finally the compound is degassed under vacm (1.5 kPa), mixed with Ambosol (3 percent by weight) and filtered. C16-C18-10 OE fatty alcohol (final weight 1080 g, teona 1108 g; Oh 89.2 mg of KOH / g, Teona 80.8 mg of KOH / g) is obtained as solid.

Comparative example 4: non-ionic surfactant based on 2-methylhexadecan-1-ol (2-methylhexadecan-1-ol + 10 OE by catalysis with KOH)

1st stage

To a solution of methyl palmitate (32.4 g, 120 mmol) in dry tetrahydrofuran (1500 ml) a 1 molar solution of lithium diisopropylamide (300 ml, 300 mmol) in tetrahydrofuran was added dropwise at -78 ° C under nitrogen atmosphere. After addition of DMPU (57.2 g, 447 mmol) the solution was heated to -20 ° C and stirred for 1 h at this temperature. After further cooling to -78 ° C, methyl iodide (306 g, 2150 mmol) was added dropwise and heated to 20 ° C. After addition of saturated NH4Cl solution (1000 ml) and phase separation was extracted with ethyl acetate (3 x 1000 ml), the combined organic phases were dried over sodium sulfate and released from the solvent under vacuum. The crude mixture was purified by silica gel column chromatography. Methylated methyl palmitate was obtained in 94% yield (32 g).

2nd stage

To a solution of lithium aluminum hydride (84 g, 2210 mmol) in tetrahydrofuran (3500 ml) the final product of step 1 (210 g, 740 mmol) was added at 20 ° C and stirred for 24 h at this temperature . It was heated to reflux until no signal of a carbonyl group could be observed in IR. After cooling to 20 ° C, Na2SO4 was added until hydrogen was no longer produced. After filtration, the solvent was released under vacuum and the

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alcohol in a yield of 92.5% (175 g). Gas chromatography and NMR-1H spectroscopy analysis resulted in the alcohol obtained being 87% 2-methylhexadecan-1-ol, 11% 2,2-dimethylhexadecan-1-ol and in 2% hexadecan-1-ol.

3rd stage

Mix 2-methylhexadecan-1-ol (40 g, 0.156 mol) with KOH solution (50%, 0.6 g, 0.006 mol) in a 300 ml pressure autoclave and dehydrate for 2 h at 100 ° C and 1.5 kPa. It is then inertized three times with nitrogen (up to 300 kPa), a prepressure of 100 kPa is adjusted and heated to 130 ° C. In the 50 min interval, ethylene oxide (68.6 g, 1.56 mol) is dosed to a maximum pressure of 800 kPa and after finishing the addition it is subsequently stirred for 5 h.

Finally the compound is degassed in vat (1.5 kPa), mixed with Ambosol (3 percent by weight) and filtered. 2-Methylhexadecan-1-ol-10 OE is obtained (final weight 102 g, Teona 109 g. The structure was confirmed by 1 H-NMR spectroscopy as well as size exclusion chromatography (SEC).

III) Technical application tests

The following tests were carried out with the surfactants obtained to assess their suitability for tertiary oil extraction.

Description of measurement procedures Determination of SP *

a) Principle of measurement:

The limited surface tension between water and oil was determined in a known manner by measuring the solubilization parameter SP *. The determination of the limit surface tension by means of the determination of the solubilization parameter SP * is a procedure accepted in the scientific world for the approximate determination of the limit surface tension. The solubilization parameter SP * indicates how many ml of oil per ml of surfactant used are dissolved in a microemulsion (Windsor type III). The surface tension limit to (interfacial tension; IFT) can be calculated from this by means of the IFT approximation formula “0.3 / (SP *) 2, in case the same volumes of water and oil are used (C. Huh, J. Coll. Interf. Sc., Vol. 71, no. 2 (1979)).

b) Work instructions

For the determination of SP * a measuring cylinder of 100 ml is filled with a magnetic stir bar with 20 ml of oil and 20 ml of water. To this is added 5 percent by weight or 2.5 percent by weight of surfactant (the latter in case an SP *> 10 should be determined). Then the temperature is gradually raised from 20 ° C to 90 ° C and it is observed in which temperature range a microemulsion formed.

The formation of the microemulsion can be observed visually or also with the help of conductivity measurements. A three phase system is formed (upper oil phase, microemulsion central phase, lower water phase). If the upper and lower phases are equal to large and are no longer modified for a period of 12 h, then the optimum temperature (Topt) of the microemulsion has been found. The volume of the central phase is determined. The volume of added surfactant is subtracted from this volume. The value obtained is then divided by two. This volume is now divided by the volume of surfactant added. The result is recorded as SP *.

The type of oil and water used for the determination of SP * is determined depending on the system to be studied. On the one hand, the oil itself or also a model oil such as decane or hexadecane can be used. As water, both pure water and saline water can be used to better model the proportions in the formation of oil. The composition of the aqueous phase can be adjusted, for example, in a manner corresponding to the composition of a given reservoir water.

Indications regarding the aqueous phase used and the oil phase are found in the specific description of the tests.

Test results

Determination of the solubility of the surfactants

Water with high salt content was used for the solubility test (salt content by weight percentage: 13.2% NaCl, 4.26% CaCl2, 1.05% MgCh, 0.03% Na2SO4) , which is typical of an oil field in northern Germany.

The saline solution was mixed respectively with 1% by weight of surfactant and the appearance of the solution was evaluated at different temperatures. The results are compiled in Table 1. The solubility behavior of the surfactants of example 1 and comparative example 1 is relatively similar.

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Limit surface tension determination (IFT)

The surface tension limit was determined respectively according to the general instructions described above.

The oil used was decane and as an aqueous phase the saline water also used in the solubility tests (salt content in percentage by weight: 13.2% NaCl, 4.26% CaCl2, 1.05% MgCh, 0 , 03% of Na2SO4). The results are summarized in Table 2. AT indicates according to this the temperature range, within which the microemulsion occurs and Topt indicates the optimum temperature determined as before.

In addition, tests with crude oils were performed. Two different crude oils of average weight of different origin and viscosity were used. As the aqueous phase, a saline solution was used, whose composition corresponded to the reservoir water of the crude oil used. The particularities are summarized in Table 3. The corresponding reservoir temperature was used respectively as the test temperature. The surface tensions limit limits are summarized respectively in table 4.

The results show that with the surfactants according to the invention with highly branched aliphatic residues, lower surface tensions are achieved in the water-oil system lower than with other surfactants.

Comparison of surface tension limit and phase separation time and solubility depending on the degree of branching in the hydrophobic part of surfactants

The limit surface tension was determined respectively according to the general instructions described above.

Hexadecane was used as an oil and the saline water used in the solubility tests was an aqueous phase (salt content in percentage by weight: 13.2% NaCl, 4.26% CaCl2, 1.05% MgCh, 0, 03% of Na2SO4). The water: oil ratio is 1: 1 (20 ml: 20 ml). The concentration of surfactants amounts to 2.5 percent by volume with respect to the combined volume of oil and water.

The results are summarized in table 5. Topt indicates the optimum temperature determined as before. In the last column is the time for the formation of the central balanced phase (microemulsion). This phase separation time t is minimal in the case that there is a balanced microemulsion, that is to say that there are equal volumes of oil and water next to the central phase.

A rapid phase separation time is desired so that the oil bank in formation can be formed quickly. In the case of raw oils, the phase separation is clearly slower than with corresponding n-alkane model oils (according to experience in a factor of 50). In the bibliography there are additions of short chain alcohols, which nevertheless clearly influence the optimum temperature as well as the limit surface tension.

The solubility was evaluated optically by means of 2.5% of surfactant in the water of northern Germany described (salt content in percentage by weight: 13.2% NaCl, 4.26% CaCl2, 1.05% MgCh, 0.03% Na2SO4) at different temperatures. The results are compiled in table 6.

The results show that with the surfactants according to the invention with highly branched aliphatic moieties, numerous advantages can be achieved compared to surfactants with lower branching degrees:

Lower surface tensions are obtained lower than with alkylphenyl-based surfactants with similar hydrophobic-hydrophilic equilibrium (to be distinguished by similar Topt) (see Tables 2 and 4).

Very low phase separation times. As can be deduced from Table 5, the phase separation time for the surfactant according to the invention to Topt is increased. only 2 min, while the linear surfactant according to comparative example 3 and the surfactant with a branching degree of only 1 according to comparative example 4 respectively have a phase separation time of 80 min.

Reduction of phase separation times with preservation of the low limit surface tension with addition by mixing of surfactants in accordance with the invention to surfactants that have a low surface tension limit however high phase separation times. Synergistic action as can be distinguished in table 5.

The surfactants according to the invention have better solubilities in the surfactant-water system, in particular at lower temperatures as can be distinguished in Table 1 and 6.

Table 1: solubility test results

 No.

 Surfactant TA 60 ° C 90 ° C

 Comparative Example 1

 dodecylphenol -10 OE cloudy without cloudy sediment without cloudy sediment without sediment

 Example 1

 iC-, 7-10 OE transparent cloudy without sediment small flocculations

Table 2: Kmite surface tension in the water-dean system for different surfactants

 No.

 Surfactant * CL CO IFT [mN / m] to Topt or —1 05 AT [° C]

 Comparative Example 1

 dodecylphenol -10 OE (catalysis with KOH) 2.8 0.038 52.5 5

 Comparative Example 2

 dodecylphenol -13 OE (catalysis with KOH) 1.1 0.248 69 16

 Example 1

 iC-17 -10 OE (catalysis with KOH) 8 0.005 66.6 2

 Example 2

 iC-17 -10 OE (catalysis with DMC) 11.5 0.002 63.2 1.5

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Table 3: oils and aqueous phases used for the tests

 Extraction site Deposit temperature Viscosity Density at 23 ° C [g / cm3] Salts in the aqueous phase

 Crude oil A

 Northern Germany 54 ° C 66 mPas (20 ° C) 17 mPas (50 ° C) 0.885 13.2% NaCl, 4.26% CaCl2, 1.05% MgCh, 0.03% Na2SO4

 B crude oil

 Oman 69 ° C 25 mPas (20 ° C) 8 mPas (50 ° C) 0.873 16.5% NaCl, 6.08% CaCl2 * 2 H2O, 1.9% MgCl2 * 6 H2O, 0.03% from Na2SO4

Tabelle 4: Limit surface tension measurement results

 Crude oil

 Surfactant used * CL if) IFT

 No. designation

 Crude oil A

 comparative example 1 dodecylphenol -10 OE 2 0.075

 Crude oil A

 example 1 iC17 -10 OE 3 0.033

 B crude oil

 comparative example 1 dodecylphenol -10 OE not determinable not determinable

 B crude oil

 example 1 iC17 -10 OE 19 0.0008

Table 5: Ifmite surface tension and phase separation in the northern German water system -

hexadecane for different surfactants

 Surfactant used

 Degree of branching * CL CO IFT [mN / m] to Topt d —1 05 T [min] to Topt

 No.

 Designation

 Comparative Example 3

 C16-C18 -10 OE fatty alcohol (catalysis with KOH) 0 8 0.005 59.4 80

 Comparative Example 4

 2-methylhexadecanol -10 OE (catalysis with KOH) approx. 1 7.25 0.005 58 80

 Example 1

 iC-17 -10 OE (catalysis with KOH) approx. 3.1 3 0.033 62.3 2

 Mixture of example 1 and comparative example 3 30: 70

 iC-17 -10 OE ratio (KOH catalysis): C16-C18 -10 OE fatty alcohol (KOH catalysis) 30: 70 (0.3 x 3.1) + (0.7 x 0) = approx. 1 6 0.008 60.1 5

 Mixture of comparative example 3 and butylmonoglycol 50: 50

 2.5% fatty alcohol C16-C18 -10 OE + 2.5% of nC4 -1 OE 0 2.5 0.048 46.8 10

Table 6: solubility test results

 No.

 Surfactant TA 50 ° C

 Comparative Example 3

 fatty alcohol C16-C18 -10 OE (catalysis with KOH) cloudy flocculate without sediment

 Example 1

 iC17 -10 OE transparent cloudy without sediment

 Comparative Example 4

 2-methylhexadecanol - 10 OE (catalysis with KOH) cloudy without sediment cloudy without sediment

 Mixture of example 1 and comparative example 3 30: 70

 iC17 -10 OE ratio (KOH catalysis): C16-C18 -10 OE fatty alcohol (KOH catalysis) 30: 70 slightly cloudy without sediment slightly cloudy without sediment

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Claims (16)

5 10 fifteen twenty 25 30 35 40 Four. Five 1. Surfactants of the general formula R1-X, in which in the case of R1 it is a C17H35 aliphatic alkyl moiety and in the case of X it is a hydrophilic group, characterized in that the average branching degree of the R1 moiety amounts to 2.8 to 3.7, the degree of branching being the number of methyl groups in the remainder R1 minus 1. 2. Surfactants according to claim 1, characterized in that the average branching degree of the remainder R1 amounts to 3.01 to 3.5. 3. Surfactants according to claims 1 or 2, characterized in that in the case of X it is a group selected from the group of sulfonate groups, polyoxyalkylene groups, anionically modified polyoxyalkylene groups, glucoside groups, amine oxide groups, groups cationic or betamic. 4. Surfactants according to claims 1 or 2, characterized in that they are alkylalkoxylates (A) which comprise alkoxy and / or ethoxy groups and have the general formula R1O- (CH2CH (R2) O) n (CH2CH2O) m-H (I), in which • R2 represents a straight, branched, aliphatic or aromatic chain hydrocarbon moiety with 1 to 10 carbon atoms, • n represents values from 0 to 15, • m represents values from 1 to 20, • asf as k = n + m represents values from 1 to 35, with the proviso that alkoxy and ethoxy groups, provided that both types of groups are present, can be arranged statistically, alternately or in block structure. 5. Surfactants according to claim 4, characterized in that m is greater than n. 6. Surfactants according to claims 4 or 5, characterized in that in the case of R2 it is a methyl group. 7. Surfactants according to one of claims 4 to 6, characterized in that in the above formula it is n> 1 and m> 1 and is a block copolymer, in which the alkoxy and ethoxy groups are arranged in the order indicated in the formula (I). 8. Surfactants according to one of claims 4 to 7, characterized in that m represents values from 5 to 14. 9. Surfactants according to claims 1 or 2, characterized in that they are alkylene ether sulfonates (B) comprising alkoxy and / or ethoxy groups and having the general formula R1O- (CH2CH (R2) O) n (CH2CH2O) m-R3-SO3M (II), in which • R2 represents a straight, branched, aliphatic or aromatic chain hydrocarbon moiety with 1 to 10 carbon atoms, • n 'represents values from 0 to 15, • m 'represents values from 1 to 20, • asf as k '= n' + m 'represents values from 1 to 35, • M represents H + and / or a 1-x Yx + k-valent counterion, • R3 represents a divalent hydrocarbon group with 2 to 12 carbon atoms, which may optionally present functional groups as substituents, with the proviso that alkoxy and ethoxy groups, provided that both types of groups are present, can be arranged statistically, alternately or in block structure. 10. Surfactants according to claims 1 or 2, characterized in that they are alkylethercarboxylates (C) which comprise alkoxy and / or ethoxy groups and have the general formula R1O- (CH2CH (R2) O) n (CH2CH2O) m "-R5-COOM (III), in which • R2 represents a straight, branched, aliphatic or aromatic chain hydrocarbon moiety with 1 to 10 carbon atoms, • n "represents values from 0 to 15, 5 10 fifteen twenty 25 30 • m "represents values from 1 to 20, • asf as k "= n" + m "represents values from 1 to 35, • M represents H + and / or a 1-x Yx + k-valent counterion, • R5 represents a divalent hydrocarbon group with 1 to 12 carbon atoms, with the proviso that alkoxy and ethoxy groups, provided that both types of groups are present, can be arranged statistically, alternately or in block structure. 11. Surfactants according to claims 1 or 2, characterized in that they are alkylene ether sulfates (D) which comprise alkoxy and / or ethoxy groups and have the general formula R1O- (CH2CH (R2) O) n "(CH2CH2O) m '" - SO3M (IV), in which • R2 represents a straight, branched, aliphatic or aromatic chain hydrocarbon moiety with 1 to 10 carbon atoms, • n "'represents values from 0 to 15, • m "'represents values from 1 to 20, • asf as k '"= n'" + m '"represents values from 1 to 35, • M represents H + and / or a 1-x Yx + k-valent counterion, with the proviso that alkoxy and ethoxy groups, provided that both types of groups are present, can be arranged statistically, alternately or in block structure. 12. Surfactants according to one of claims 9 to 11, characterized in that m 'is greater than n' or because m "is greater than n" or because m '"is greater than n'". 13. Surfactants according to one of claims 9 to 12, characterized in that in the case of R2 it is a methyl group. 14. Surfactants according to one of claims 9 to 13, characterized in that in formulas (II) and (III) and (IV) they are n 'on "or n'"> 1 and are m 'om "or m' "> 1 and is a block copolymer, in which the alkoxy groups and the ethoxy groups as well as the sulfonic acid group or the carboxyl group or the sulfate group are arranged in the order indicated in formulas (II) or ( III) or (IV). 15. Surfactants according to one of claims 9 to 14, characterized in that m 'or m "or m'" represent values from 1 to 15. 16. Use of surfactants according to one of claims 1 to 17 for the extraction of tertiary oil.