EP1697314A2

EP1697314A2 - Method for producing alkylaryl compounds

Info

Publication number: EP1697314A2
Application number: EP04804045A
Authority: EP
Inventors: Nils Bottke; Jürgen Tropsch; Thomas Narbeshuber; Jürgen STEPHAN; Michael Röper; Thomas Heidemann; Ulrich Steinbrenner; Regina Benfer
Original assignee: BASF SE
Current assignee: BASF SE
Priority date: 2003-12-19
Filing date: 2004-12-17
Publication date: 2006-09-06
Also published as: CA2544867A1; US20070142258A1; WO2005061447A3; KR20060134966A; MY136695A; BRPI0417365A; TW200530147A; CN1997611A; WO2005061447A2; DE10360026A1; ZA200604943B

Abstract

The production of alkylaryl compounds comprises the following stages: a) reaction of a C4/C5 olefin mixture on a metathesis catalyst to produce a C4-8 olefin mixture containing 2-pentene and the optional isolation of the C4-8 olefin mixture; b) isolation of between 5 and 100 % of the 2-pentene obtained in step a) and subsequent reaction on an isomerisation catalyst to form a mixture of 2-pentene and 1-pentene, which is returned to stage a); c) dimerisation of the C4-8 olefin mixture obtained in stage b) after the isolation process, to form a mixture containing C8-16 olefins, isolation of the C8-16 olefins and optional isolation of a partial stream of the latter; d) reaction of the C8-16 olefin mixtures obtained in stage c) or the partial stream with an aromatic hydrocarbon in the presence of an alkylation catalyst, to form alkyl aromatic compounds, whereby prior to the reaction an additional 0 to 60 wt. % linear olefins, in relation to the C8-16 olefin mixtures obtained in stage c), can be added; e) optional sulphonation of the alkyl aromatic compounds obtained in stage d) and neutralisation to form alkylaryl sulphonates, whereby prior to the sulphonation an additional 0 to 60 wt. % linear alkyl benzols, in relation to the alkyl aromatic compounds obtained in stage d), can be added, provided that there were no admixtures in stage d); f) optional mixing of the alkylaryl sulphonates obtained in stage e) with between 0 and 60 wt. %, linear alkylaryl sulphonates, in relation to the alkylaryl sulphonates obtained in stage e), provided that there were no admixtures in stages d) and e).

Description

Process for the preparation of alkylaryl compounds

description

The present invention relates to processes for the preparation of alkylaryl compounds, in particular alkylarylsulfonates, alkyl aryls and alkylarylsulfonates obtainable by the process, the use of the alkylarylsulfonates as surfactants, preferably in washing and cleaning agents, and washing and cleaning agents containing them.

Alkylbenzenesulfonates (ABS) have long been used as surfactants in detergents and cleaning agents. After such surfactants based on tetrapropylene were initially used, but were poorly biodegradable, alkylbenzenesulfonates (LAS) which were as linear as possible were subsequently produced and used. However, linear alkylbenzenesulfonates do not have adequate property profiles in all areas of application.

For example, it would be beneficial to improve their cold wash properties or their properties in hard water. The ease of formulation, which results from the viscosity of the sulfonates and their solubility, is also desirable. These improved properties are achieved by slightly branched compounds or mixtures of slightly branched compounds with linear compounds, but it is necessary to achieve the correct degree of branching and / or the correct degree of mixture. Branches that are too strong adversely affect the biodegradability of the products. Products that are too linear negatively affect the viscosity and solubility of the sulfonates.

In addition, the proportion of terminal phenylalkanes (2-phenylalkanes and 3-phenylalkanes) to internal phenylalkanes (4-, 5-, 6- etc. phenylalkanes) plays a role in the product properties. A 2-phenyl content of approximately 30% and a 2- and 3-phenyl content of approximately 50% can be advantageous in terms of product quality (solubility, viscosity, washing properties).

Surfactants with too high 2- and 3-phenyl contents can have the main disadvantage that the processability of the products suffers from a sharp increase in the viscosity of the sulfonates. In addition, the solubility behavior may not be optimal. For example, the Krafft point of a solution of LAS with very high or very low 2- and 3-phenyl levels is up to 10-20 ° C higher than with an optimal choice of the 2- and 3-phenyl levels.

The process according to the invention has the significant advantage that the combination of metathesis and dimerization with intermediate isomerization of 2-pentene gives a unique olefin mixture which, after alkylation of an aromatic, sulfonation and neutralization, provides a surfactant which is characterized by its Combination of excellent application properties (solubility, viscosity, stability against water hardness, washing properties, biodegradability). With regard to the biodegradability of alkylarylsulfonates, compounds which are less strongly adsorbed on sewage sludge than conventional LAS are particularly advantageous.

To a certain extent, branched alkylbenzenesulfonates have therefore been developed.

WO 99/05241 relates to cleaning agents which contain branched alkylarylsulfonates as surfactants. The alkylarylsulfonates are obtained by dimerization of olefins to vinylidene olefins and subsequent alkylation of benzene over a shape-selective catalyst such as MOR or BEA. This is followed by sulfonation.

WO 02/44114 relates to a process for the preparation of alkylarylsulfonates, in which mono-branched C ₁ -C ₄ -olefins obtainable by different processes are reacted with an aromatic hydrocarbon in the presence of zeolites of the faujasite type as alkylation catalyst. The C _0- ι ₄ -olefins can be prepared, for example, by metathesis of a C ₄ -olefin mixture, followed by dimerization of the 2-pentene and / or 3-hexene obtained on a dimerization catalyst. Alternative methods are extraction, Fischer-Tropsch synthesis, dimerization or isomerization of olefins.

WO 02/14266 relates to a process for the preparation of alkylarylsulfonates, in which a metathesis of a C ₄ -olefin mixture for the preparation of 2-pentene and / or 3-hexene is first carried out and the products are subjected to dimerization. An alkylation then takes place in the presence of an alkylation catalyst, followed by sulfonation and neutralization. The olefins hitherto used for alkylation sometimes have too high or too low a degree of branching or do not result in a non-optimal ratio of terminal to internal phenylalkanes. On the other hand, they are made from expensive starting materials such as propene or alpha-olefins, and in some cases the proportion of olefin fractions that are of interest for the preparation of surfactants is only about 20%. This leads to expensive refurbishment steps. DE-A 102 61 481, which is older and not prepublished, relates to a process for the preparation of alkylarylsulfonates by

a) reacting a C ₄ -olefin mixture on a metathesis catalyst to produce an olefin mixture containing 2-pentene and / or 3-hexene and optionally separating 2-pentene and / or 3-hexene,

b) Dimerization of the 2-pentene and / or 3-hexene obtained in stage a) in the presence of a dimerization catalyst to give a Cι _0- ι ₂ -olefins

Mixture, separation of the C _10- ι ₂ -olefins and separation of 5 to 30 wt .-%, based on the separated C _0- ι ₂ -olefins, of low boiler components of

Cι _0- ι ₂ olefins,

c) reaction of the C ₁₀ -ι ₂ -olefin mixtures obtained in stage b) with an aromatic hydrocarbon in the presence of an alkylation catalyst to form alkyl aromatic compounds, 0 to 60% by weight, preferably 0 to 40% by weight, in addition to the reaction %, based on the C ₁ -C ₂ -olefin mixtures obtained in stage b), of linear olefins can be added,

d) sulfonation of the alkyl aromatic compounds obtained in step c) and neutralization to alkylarylsulfonates, 0 to 60% by weight, preferably 0 to 50% by weight, based on the alkyl aromatic compounds obtained in step c), being additionally present before the sulfonation linear alkylbenzenes can be added, provided that no addition has been made in step c),

e) optionally mixing the alkylarylsulfonates obtained in stage d) with 0 to 60% by weight, preferably 0 to 30% by weight, based on the alkylarylsulfonates obtained in stage d), on linear alkylarylsulfonates, provided that no admixtures are present Levels c) and d) have taken place. The latter methods do not always lead to products that show a desired range of properties.

The object of the present invention is to provide a process for the preparation of alkylaryl compounds, in particular alkylarylsulfonates, which are at least partially branched and thus have advantageous properties over the known compounds for use in detergents and cleaning agents. In particular, they should have a suitable property profile from biodegradability, insensitivity to water hardness, solubility and viscosity during manufacture and use. In addition, the alkylarylsulfonates should be inexpensive to produce.

The object is achieved according to the invention by a process for the preparation of alkylaryl compounds

a) reaction of a Cψ'Cs-olefin mixture on a metathesis catalyst αir preparation of a 2-pentene-containing C ^ -olefin mixture and optionally separation of the C _-8 -olefin mixture,

b) separation of 5 to 100% of the 2-pentene obtained in stage a) and subsequent reaction on an isomerization catalyst to give a mixture of 2-pentene and 1-pentene which is recycled in stage a),

c) Dimerization of the C _-8 - obtained in step b) after the separation

Olefin mixture in the presence of a dimerization catalyst to give a mixture containing C ₈ i ₆ olefins, separation of the C ₈ i ₆ olefins and, if appropriate, separation of a partial stream thereof,

d) reaction of the C _8-16 olefin mixtures obtained in stage c) or of the substream with an aromatic hydrocarbon in the presence of an alkylation catalyst to form alkylaromatic compounds, with an additional 0 to 60% by weight, based on that in stage, before the reaction c) C _8-16 olefin mixtures obtained, which can be added to linear olefins, e) optionally sulfonation of the alkyl aromatic compounds obtained in stage d) and neutralization to alkylarylsulfonates, it being possible to add 0 to 60% by weight, based on the alkyl aromatic compounds obtained in stage d), of linear alkyl benzenes before the sulfonation, if no addition has been made in stage d),

f) optionally mixing the alkylarylsulfonates obtained in stage e) with 0 to 60% by weight, based on the alkylarylsulfonates obtained in stage e), of linear alkylarylsulfonates, provided that no admixtures are present in

Levels d) and e) have taken place.

The combination of a metathesis of C Cs-olefins with a subsequent isomerization of 2-pentene and dimerization and alkylation of aromatic hydrocarbons allows, under the conditions mentioned, the use of inexpensive starting materials and manufacturing processes which make the desired products available in high yields ,

It has been found according to the invention that by metathesis of C 1 -C 6 -olefins, products are obtained which, after partial isomerization and recycling of 2-pentene, can be dimerized to give slightly branched C _8-16 -olefin mixtures. By setting the desired degree of branching, for example by selective dimerization or separation of a partial stream and / or addition of linear olefins, these mixtures can advantageously be used in the alkylation of aromatic hydrocarbons, products being obtained which, after sulfonation and neutralization, give surfactants which have outstanding properties, in particular with regard to the sensitivity to hardness-forming ions, the solubility of the sulfonates, the viscosity of the sulfonates and their washing properties. In addition, the present method is extremely cost-effective since the product streams can be designed so flexibly that no by-products are generated. Starting from a C ₄ stream, after a first C ₅ recycle then starting from a C ^ Cs stream, linear internal olefins are produced by the metathesis according to the invention, which are then converted into branched olefins via the dimerization step.

Step a) of the process according to the invention is the reaction of a C 1 -C 6 _δ -olefin mixture over a metathesis catalyst for the production of a C _4-8 -olefin mixture and, if appropriate, separation of C _4-8 olefins. The metathesis can be carried out, for example, as described in WO 00/39058 or DE-A-100 13 253.

In its simplest form, olefin metathesis (disproportionation) describes the reversible, metal-catalyzed transalkylidation of olefins by breaking or reforming C = C double bonds according to the following equation:

In the special case of metathesis of acyclic olefins, a distinction is made between self-metathesis, in which an olefin changes into a mixture of two olefins of different molar mass (for example: propene → ethene + 2-butene), and cross or co-metathesis, which is a reaction of two describes different olefins (propene + 1-butene -> • ethene + 2-pentene). If one of the reactants is ethene, this is generally referred to as ethenolysis.

In principle, homogeneous and heterogeneous transition metal compounds are suitable as metathesis catalysts, in particular those of VI. to VIII. Subgroup of the periodic table of the elements and homogeneous and heterogeneous catalyst systems in which these compounds are contained.

Different metathesis processes which start from C ₄ streams can be used according to the invention.

DE-A-199 32 060 relates to a process for the preparation of C ₅ - / C ₆ -ofins by reacting an output stream which contains 1-butene, 2-butene and isobutene to give a mixture of C _2-6 -olefins. In this way, propene in particular is obtained from butenes. In addition, witches and methylpentene are removed as products. No ethene is added in the metathesis. Optionally, ethene formed in the metathesis is returned to the reactor. A preferred process for the production of propene and hexene, if appropriate, from a raffinate-II starting stream containing oiefinic C-hydrocarbons is characterized in that

a) in the presence of a metathesis catalyst, the at least one compound of a metal of VI. b, VII. b or VIII. subgroup of the periodic table of the elements, a metathesis reaction is carried out, in the context of which butenes contained in the input stream with ethene to a mixture containing ethene, propene, butenes, 2-pentene, 3-hexene and butanes are implemented, based on the butenes up to 0.6 molar equivalents of ethene can be used,

b) the discharge stream obtained in this way is first separated by distillation into a low boiler fraction A optionally containing C ₂ -C ₃ olefins and into a high boiler fraction containing C ₄ -C ₆ olefins and butanes,

c) the low boiler fraction A optionally obtained from b) is then separated by distillation into an ethene-containing fraction and a propene-containing fraction, the ethene-containing fraction being returned to process step a) and the propene-containing fraction being discharged as product,

d) the high boiler fraction obtained from b) is then separated by distillation into a low boiler fraction B containing butenes and butanes, a medium boiler fraction C containing 2-pentene and a high boiler fraction D containing 3-hexene,

e) wherein the fractions B and optionally C are completely or partially returned to process step a) and the fraction D and optionally C are discharged as a product.

An alternative preferred method for producing C ₆ -alkenes from a hydrocarbon stream containing C ₄ -alkenes (starting stream C ₄ ⁼ ) is characterized in that

a) in a step a) the stream C ⁼ with a metathesis catalyst which contains at least one compound of a metal of VI. b, VII. b or VIII. Subgroup of the Periodic Table of the Elements contains, at least one Part of the C ₄ alkenes to C ₂ - to C is reacted for ₆ -alkenes, C and the thus formed ₂ - to C ₆ alkenes containing stream (. Current C ₂ ⁼ ₆₎ separated from the metathesis catalyst,

b) removed in a step b) from stream C _2-6 ⁼ ethylene by distillation and thus produces a stream containing C ₃ - C ₆ -alkenes (stream C _3-6 ⁼ ) and a stream consisting essentially of ethylene (stream C ₂ ⁼ ) produces,

c) in a step c) the stream C _3-6 ^{= by} distillation into a stream consisting essentially of propylene (stream C ₃ ⁼ ), a stream consisting essentially of C ₆ -alkenes (stream C ₆ ⁼ ) and one or several material streams selected from the following group: a material stream consisting essentially of C ₄ -alkenes (stream C ⁼ ), a material stream consisting essentially of C ₅ -alkenes (stream C ₅ ⁼ ) and one consisting essentially of C ₄ - and C ₅ -alkenes existing material stream (stream C _4-5 ⁼ ),

d) in a step d) one or more streams or parts thereof, selected from the group stream C ₄ ⁼ , stream C ₅ ⁼ and stream C _4-5 ^{= used in} whole or in part for the production of output stream C ₄ ⁼ (recycling stream) , and, if appropriate, the stream or streams or parts thereof which are not recycled stream are discharged.

The output current C ⁼ is subjected to a metathesis reaction using a method as described in EP-A 1069101.

The processes are carried out with the addition of partially isomerized 2-pentene.

The metathesis reaction according to step a) is preferably carried out in the presence of heterogeneous metathesis catalysts which are not or only slightly isomerization-active and which are selected from the class of transition metal compounds of metals of VI which are applied to inorganic supports. b, VII. b or VIII. Group of the Periodic Table of the Elements are selected.

Rhenium oxide on a support, preferably on γ-aluminum oxide or on Al ₂ O ₃ / B ₂ O ₃ / SiO ₂ mixed supports, is preferably used as the metathesis catalyst. In particular, the catalyst used is Re ₂ O ₇ / γ-Al ₂ O ₃ with a rhenium oxide content of 1 to 20% by weight, preferably 3 to 15% by weight, particularly preferably 6 to 12% by weight.

In the liquid mode of operation, the metathesis is preferably carried out at a temperature of 0 to 150 ° C., particularly preferably 20 to 80 ° C. and a pressure of 2 to 200 bar, particularly preferably 5 to 30 bar.

If the metathesis is carried out in the gas phase, the temperature is preferably 20 to 300 ° C., particularly preferably 50 to 200 ° C. The pressure in this case is preferably 1 to 20 bar, particularly preferably 1 to 5 bar. Detailed information on the metathesis reaction can again be found in EP-A 1069101.

The subsequent processing of the current C _2-6 ⁼ formed in the metathesis takes place in steps c) and d) described at the outset.

The individual streams and fractions may contain or consist of the compounds / olefins mentioned. In the event that they consist of the streams or compounds, the presence of smaller amounts of other hydrocarbons is not excluded.

In order to explain the process according to the invention in more detail, the implementation taking place in the metathesis reactor is divided into three important individual reactions:

1. Cross metathesis of 1-butene with 2-butene

1-butene 2-butene propene 2-pentene

2. Self-metathesis of 1-butene

1-butene ethene 3-witch 3. If necessary, ethenolysis of 2-butene

^' iKa]

+ ^

2-butene ethene propene

The recycling of the partially isomerized 2-pentene results in further longer-chain products.

Depending on the respective need for the target products propene and hexene / heptene / octene (the name hexene etc. includes, among other things, possibly formed isomers) or 2-pentene, the external mass balance of the process can be targeted through variable use of ethene and can be influenced by shifting the equilibrium by returning certain partial flows. For example, the 3-hexene yield is increased in that the return of 2-pentene to the metathesis step suppresses the cross-metathesis of 1-butene with 2-butene, so that no or as little as possible 1-butene is consumed here. In the then preferred self-metathesis of 1-butene to 3-hexene, ethene is additionally formed, which reacts in a subsequent reaction with 2-butene to give the valuable product propene.

Olefin mixtures containing 1-butene and 2-butene and optionally isobutene are obtained as a C ₄ fraction in various cracking processes such as steam cracking or FCC cracking. Alternatively, butene mixtures, such as those obtained in the dehydrogenation of butanes or by dimerization of ethene, can be used. Butanes contained in the C ₄ fraction are inert. Before the metathesis step according to the invention, dienes, alkynes or enynes are removed using customary methods such as extraction or selective hydrogenation.

The butene content of the C ₄ fraction used in the process is 1 to 100% by weight, preferably 60 to 90% by weight. The butene content relates to 1-butene, 2-butene and isobutene.

A C ₄ fraction is preferably used, such as is obtained in steam or FCC cracking or in the dehydrogenation of butane. Raffinate II is preferably used as the C ₄ fraction, the C stream before the metathesis reaction being freed from disturbing impurities by appropriate treatment on protective adsorber beds, preferably on high-surface area aluminum oxides or molecular sieves.

In step d), the separation into low boiler fraction B, medium boiler fraction C and high boiler fraction D can be carried out, for example, in a dividing wall column. The low boiler fraction B is obtained overhead, the medium boiler fraction C via a medium discharge and the high boiler fraction D as the bottom.

5 to 100%, preferably 20 to 80%, in particular 40 to 60% of the 2-pentene obtained in stage a) are separated off and subsequently reacted on an isomerization catalyst to give a mixture of 2-pentene and 1-pentene, the resultant Mixture in stage a) is recycled. As a result, butyl units are introduced into the metathesis in addition to the methylene, ethylene and propylene units, so that 2-hexene, 3-heptene and 4-octene also result as products. A mixture of butenes, pentenes, hexenes, heptenes and octenes is then drawn off from the metathesis / isomerization unit and passed into the dimerization. The stream preferably contains 0 to 10 mol% of butenes, 10 to 40% of pentenes, 60 to 80% of hexenes, 5 to 30% of heptenes and 0 to 15% of octenes, particularly preferably 0 to 5 mol% of butenes, 15 to 25% Pentenes, 60 to 75% hexenes, 10 to 30% heptenes and 0 to 10% octenes, the total amount being 100 mol%.

The metathesis reaction is preferably carried out in the presence of heterogeneous, not or only slightly isomerization-active metathesis catalysts, which belong to the class of transition metal compounds of metals of the VI applied to inorganic supports. b, VII. b or VIII group of the Periodic Table of the Elements are selected.

Rhenium oxide on a support, preferably on γ-aluminum oxide or on, is preferred as the metathesis catalyst used.

In particular, the catalyst used is Re ₂ O ₇ / γ-Al ₂ O ₃ with a rhenium oxide content of 1 to 20% by weight, preferably 3 to 15% by weight, particularly preferably 6 to 12% by weight. In the liquid mode of operation, the metathesis is preferably carried out at a temperature of 0 to 150 ° C., particularly preferably 20 to 110 ° C. and a pressure of 2 to 200 bar, particularly preferably 5 to 40 bar.

If the metathesis is carried out in the gas phase, the temperature is preferably 20 to 300 ° C., particularly preferably 50 to 200 ° C. The pressure in this case is preferably 1 to 20 bar, particularly preferably 1 to 5 bar.

To improve the cycle time of the catalysts used, especially the supported catalysts, the use of feed cleaning on adsorber beds (guard beds) is recommended. The protective bed serves to dry the C ₄ C ₅ stream and to remove substances which can act as a catalyst poison in the subsequent metathesis step. The preferred adsorbent materials are Selexsorb CD and CDO as well as 3Ä and NaX molecular sieves (13X). Cleaning takes place in drying towers at temperatures and pressures, which are preferably selected so that all components are in the liquid phase. If necessary, the cleaning step for preheating the feed is used for the subsequent metathesis step. It can be advantageous to combine several cleaning steps with each other or to connect them in series.

Pressure and temperature in the metathesis step are selected so that all reactants are in the liquid phase (usually T = 0 to 150 ° C, preferably 20 to 80 ° C; p = 2 to 200 bar). Alternatively, however, it can be advantageous, particularly in the case of feed streams with a higher isobutene content, to carry out the reaction in the gas phase and / or to use a catalyst which has a lower acidity.

As a rule, the reaction is complete after 1 s to 1 h, preferably after 30 s to 30 min. It can be carried out continuously or batchwise in reactors, such as pressurized gas vessels, flow tubes or reactive distillation devices, flow tubes being preferred. Stage b)

In stage b), part of the 2-pentene obtained in stage a) is separated off, converted to a mixture of 2-pentene and 1-pentene on an isomerization catalyst, and the mixture thus obtained is returned to stage a).

The isomerization of 2-pentene to 1-pentene is an equilibrium reaction. Cis-2-pentene, trans-2-pentene and 1-pentene exist side by side in equilibrium. The reaction from 2-pentene to 1-pentene is weakly endothermic, so that an increase in temperature shifts the equilibrium towards 1-pentene. The thermodynamic data are listed in D. Stull, "The Chemical Thermodynamics of Organic Compounds", J. Wiley, New York 1969.

The isomerization. preferably takes place at temperatures between 100 and 500 ° C. There is no further restriction on the choice of the isomerization catalyst, provided that it is able to effect the intended isomerization. For example, basic catalysts or zeolite-based catalysts are used for this purpose, and the isomerization can also be carried out under hydrogenating conditions on contacts containing precious metals.

EP-A 0 718 036 specifically describes the use of alkaline earth oxides on aluminum oxide as a catalyst. DE-A 33 190 99 lists catalysts based on mixed aluminum oxide / silicon oxide supports which are doped with oxides of alkaline earth metals, boron group metals, lanthanides or elements of the iron group. EP-A 0 419 630 discloses a catalyst made from polymorphic magnesium / aluminum oxides. An alkali-soaked gamma alumina is disclosed in JP 57043055 as a double bond isomerization catalyst. An isomerization catalyst consisting of manganese oxide on aluminum oxide can be found in US 4,289,919. EP-A Ö 234 498 describes an isomerization catalyst composed of magnesium, alkali metal and zirconium oxides dispersed on an aluminum support. An alumina catalyst that additionally contains sodium oxide and silicon oxide is taught in US 4,229,610.

Examples of zeolite-based contacts can be found, for example, in EP-A 0 129 899, which teaches the use of zeolites of the pentasil type. Mol sieves exchanged with alkali or alkaline earth metals are described in US 3,475,511. In US 4,749,819 the use of aluminosilicates with an 8 or 10 Ring channel structure mentioned as double bond isomerization catalysts. Zeolites in the alkali or alkaline earth form are disclosed in US 4,992,613. Catalysts based on crystalline borosilicates are described in US 4,499,326.

Stage c)

In step c), the C Cs-olefin mixture obtained in step b) is dimerized in the presence of a dimerization catalyst to give a C _8-16 -olefin mixture.

The dimer-olefin mixtures obtained according to the invention preferably have an average degree of branching in the range from 1 to 2.5, particularly preferably 1 to 2.0, in particular 1 to 1.5 and especially 1 to 1.2. The degree of branching of a pure olefin is defined as the number of carbon atoms which are linked to three carbon atoms, plus two times the number of carbon atoms which are linked to 4 carbon atoms. The degree of branching of a pure olefin can easily be measured after total hydrogenation to the alkane via ¹ H-NMR via the integration of the signals of the methyl groups relative to the methylene and methine protons.

In the case of mixtures of olefins, the degrees of branching are weighted with the molar percentages, and an average degree of branching is thus calculated.

The molar proportions are optimally determined using gas chromatography.

The type of branching in the olefin is preferably such that, after hydrogenation, less than 10%, preferably less than 5%, particularly preferably less than 1%, alkanes are obtained which are not methyl, dimethyl or ethyl methyl. and count diethylalkanes. This means that the branches are only methyl and ethyl branches.

According to a particularly preferred embodiment of the invention, the dimerization is carried out in such a way that the catalysis directly provides the desired advantageous composition in relation to the branching structures.

C ₈ i ₆ olefins are formed in the dimerization. From this stream a part of current (the total current from 59 to 99 mol%), preferably separated, preferably containing less than 5 mole% C _<10, 5 to 15% C _10, 35 to 55% _{C11 (25} to 45% C ₁₂ , 5 to 15%

C | ₃ and <5% C> ₁₃ , preferably <2 mol% C < ₁₀ , 5 to 15% C-ι _0l 40 to 50% Cn, 30 to 50% C ₁₂ , 5 to 15% C ₁₃ and <2% C _{> 13} . The sum is 100 mol%. The stream into the isomerization unit is preferably selected such that> 70%, preferably> 80% product of value according to the composition indicated above results after the isomerization.

This olefin stream is now used for the alkylation in stage d).

According to a further embodiment of the invention, the C _8-16 olefins obtained are separated off and 5 to 30% by weight, preferably 5 to 20% by weight, in particular up to 10 to 20% by weight, based on the separated C _{8 -16-olefins,} low-boiling constituents of the C _8- ι ₆ olefins are separated. Has as low-boiling components, the proportion of C denotes _8- ι ₆ -Olefingemischs which first merges at a distillation or the lowest boiling point. The weight fraction mentioned thus corresponds to the fraction which initially passes over in a distillation and can thus be separated off. However, the separation can also be carried out using any other suitable method. In particular, fractional distillation is carried out. As a result of the separation which is preferably carried out according to the invention, the multiply branched olefins are partly or preferably completely separated from the C _8-16 -olefin mixture. The removal can also be carried out in such a way that at least 80%, preferably at least 90%, in particular at least 95% of the double or multiple-branched olefins are removed. In the C _8- ι ₆ olefin mixture at the end of step c) so as to leave the linear and mono-branched olefins, and optionally minor proportions of multiply branched olefins. Suitable separation methods and analytical methods for determining the content of multiply branched olefins are known to the person skilled in the art.

The embodiments mentioned can be combined with the addition of linear olefins in stage d), linear alkylbenzenes in stage e), linear alkylarylsulfonates in stage f) or combinations thereof. However, it is also possible to dispense with the addition of such linear connections.

If linear compounds are added in stages d), e) and / or f), then in one embodiment it is possible to dispense with the removal of low boiler components in stage c).

In the dimerization mixture, <30, preferably <10% by weight alkanes and <5% by weight. % not - C _8-16 olefins may be included. The internal linear pentenes, hexenes, heptenes and octenes contained in the metathesis product are preferably used for the dimerization.

^• The dimerization can be carried out homogeneously or heterogeneously. The homogeneously catalyzed dimerization can be varied within wide limits with regard to the branching structures. In addition to nickel systems, Ti, Zr, Cr or Fe systems can be used, for example, which can be modified in a targeted manner using further cocatalysts and ligands. The homogeneously catalyzed dimerization is particularly preferably catalyzed with aluminum alkyl AIR ₃ in the absence of transition metals. While these α-olefins selectively convert to vinylidenes under very mild conditions, the corresponding conversion of internal olefins also succeeds under more drastic conditions. Dimers with a high vinylidene content are also formed here. The proportion of double and triple branched isomers is extremely low.

The AIR ₃ -catalyzed dimerization is preferably carried out at temperatures in the range from 150 to 300.degree. C., particularly preferably 180 to 240.degree. C., in particular 210 to 230.degree. C., the catalyst is preferably separated off by distillation at the bottom and returned to the catalysis.

Combinations of oxides of metals from subgroup VIII with aluminum oxide on support materials made of silicon and titanium oxides, as are known, for example, from DE-A-43 39 713, are advantageously used for heterogeneous catalysis. The heterogeneous catalyst can be used in a fixed bed - then preferably in coarse-grained form as 1 to 1.5 mm grit - or suspended (particle size 0.05 to 0.5 mm). In the case of heterogeneous implementation, the dimerization is advantageously carried out in a closed system at temperatures of 80 to 200 ° C., preferably 100 to 180 ° C., under the pressure prevailing at the reaction temperature, optionally also under a protective gas overpressure. In order to achieve optimal sales, the reaction mixture is circulated several times, with a certain proportion of the circulating product being continuously discharged and replaced by starting material.

In the dimerization according to the invention, mixtures of monounsaturated hydrocarbons are obtained, the components of which predominantly have twice the chain length as the starting olefins. With C- | ₂ -olefin mixtures preferably carry the main chain at the branching points, methyl or ethyl groups.

The olefin mixtures obtainable by the above process (cf. WO 00/39058) represent valuable intermediates, in particular for the preparation of branched alkyl aromatics for the preparation of surfactants described below.

Stage d)

In step d), the C ₈ -i ₆ olefin mixture obtained in step c) is reacted with an aromatic hydrocarbon in the presence of an alkylation catalyst to form alkyl aromatic compounds.

The C ₈ i ₆ olefin mixture used in stage d) has an optimal structure / linearity. This means that the degree of branching and the type of branching are optimally selected in order to obtain advantageous alkylaromatic compounds in stage d). The setting of the optimal employed in step d) C _8- ι ₆ olefin mixture can be carried out by admixing linear olefins. However, higher branched olefins are preferably separated off instead of admixing linear olefins. A suitable catalyst is particularly preferably combined with a suitable method to arrive at the optimum -olefin ι ₆ C ₈ in the dimerization. In this procedure, the desired structures are obtained directly in the alkylation. In this case, the addition of linear olefins and the separation of higher branched olefins can be dispensed with. Combinations of the procedures described are also possible.

If a low boiler removal is carried out in stage c), 0 to 60% by weight, preferably 0 to 50% by weight, in particular 0 to 30% by weight, based on the stage, can optionally be used in stage d) c) C _{8 to} ₆ olefin mixtures obtained are added to linear olefins. If linear olefins are added, their amount is at least 1% by weight, preferably at least 5% by weight, in particular at least 10% by weight.

If, according to the second embodiment of the invention, no low boiler removal is carried out in stage c), in at least one of stages d), e) and f) 5 to 60% by weight, based in each case on the mixtures obtained in the previous step, of the linear compounds. This means that additional linear olefins are added in stage d) and / or additional linear alkylbenzenes are added in stage e) and / or additional linear alkylarylsulfonates are added in stage e). Linear compounds can thus be added in each of stages c), d) and e), as well as in individual or two of the stages. In step c) 5 to 60% by weight, preferably 10 to 50% by weight, in particular 10 to 30% by weight, based on the C _0- ι ₂ -olefin mixtures obtained in step c), can be linear Olefins can be added.

In relation to stages d), e) and f) in total, preferably at most 60% by weight, particularly preferably at most 40% by weight, in particular at most 30% by weight, of the linear compounds are added. If this maximum quantity has already been reached by adding one of the stages, linear connections are not added in the other stages.

By adding the linear compounds, the property profile of the alkylarylsulfonates can be adapted to the particular desired field of application and requirement profile in addition to the advantageous synthesis sequence.

The lower limits mentioned in each case can be combined with the respectively mentioned upper limits to form areas which are possible according to the invention.

An alkylation catalyst is preferably used, which leads to alkyl aromatic compounds which have one to three carbon atoms in the alkyl radical and an H / C index of 1.

In principle, the alkylation can be carried out in the presence of any alkylation catalysts.

Although AICI ₃ and HF can be used in principle, heterogeneous or shape-selective catalysts offer advantages. For reasons of plant safety and environmental protection, solid catalysts are preferred today, these include, for example, the fluorinated Si / Al catalyst used in the DE-TAL process, a number of shape-selective catalysts or supported metal oxide catalysts, as well as layered silicates and clays. When selecting the catalyst, it is important, regardless of the large influence of the feedstock used, to minimize compounds formed by the catalyst, which are characterized in that they contain carbon atoms with an H / C index of 0 in the alkyl radical. Furthermore, compounds are to be formed which have an average of 1 to 3 carbon atoms in the alkyl radical with an H / C index of 1. This can be achieved in particular by selecting suitable catalysts which, on the one hand, suppress the formation of the undesired products due to their geometry and, on the other hand, permit a sufficient reaction rate.

The alkyl aromatic compounds according to the invention have a characteristic proportion of primary, secondary, tertiary and quaternary carbon atoms in the alkyl radical (side chain). This is reflected in the number of carbon atoms in the alkyl radical with an H / C index from 0 to 3. The H / C index defines the number of protons per carbon atom in the alkyl radical. The mixtures of alkylaromatic compounds according to the invention preferably have only a small proportion of carbon atoms in the alkyl radical with an H / C index of 0. The proportion of carbon atoms in the alkyl radical with an H / C index of 0 on average of all compounds is preferably <15%, particularly preferably <10%. The proportion of carbon atoms in the alkyl radical with an H / C index of 0, which are simultaneously bound to the aromatics, is> 80%, preferably> 90%, particularly preferably> 95% of all carbon atoms in the alkyl radical with an H / C index from 0.

The mixtures of alkylaromatic compounds according to the invention preferably have on average 1 to 3, preferably 1 to 2.5, particularly preferably 1 to 2 carbon atoms in the side chain (ie without counting the aromatic C atoms) with an H / C index of 1 on. The proportion of compounds with three carbon atoms of this type is preferably <30%, particularly preferably <20%, in particular <10%.

The proportion of carbon atoms which have a specific H / C index can be controlled by a suitable choice of the catalyst used. Preferred catalysts with which advantageous H / C distributions are achieved are mordenite, β-zeolite, L-zeolite, MCM-58, MCM-68 and faujasite. Mordenite and faujasite are particularly preferred.

When selecting the catalysts, attention should also be paid to their tendency to deactivate. One-dimensional pore systems usually have the disadvantage of rapid clogging of the pores by degradation or build-up products from the Process on. Catalysts with multidimensional pore systems are therefore preferred.

The catalysts used can be of natural or synthetic origin, the properties of which can be adjusted to a certain extent by methods known from the literature (e.g. ion exchange, steaming, blocking of acidic centers, washing out of extra-lattice species, etc.). It is important for the present invention that the catalysts are at least partially acidic in character.

Depending on the type of application, the catalysts are available either as powder or as shaped bodies. The connections between the matrices of the shaped bodies ensure adequate mechanical stability, but free access of the molecules to the active constituents of the catalysts must be ensured by means of sufficient porosity of the matrices. The production of such moldings is known from the literature and is carried out according to the prior art.

Preferred reaction procedure

The alkylation is carried out in such a way that the aromatics (the aromatics mixture) and the olefin (mixture) are allowed to react with the catalyst in a suitable reaction zone by contacting them, the reaction mixture is worked up after the reaction and the valuable products are thus obtained.

Suitable reaction zones are e.g. Tube reactors or stirred tanks. If the catalyst is in solid form, it can be used either as a slurry, as a fixed bed or as a fluidized bed. Execution as a catalytic distillation is also possible.

The reactants are either in a liquid and / or in a gaseous state.

The reaction temperature is chosen so that on the one hand the conversion of the olefin is as complete as possible and on the other hand as few by-products as possible are formed. The choice of temperature control also depends crucially on the chosen catalyst. Reaction temperatures between 50 ° C and 500 ° C (preferably 80 to 350 ° C, particularly preferably 80-250 ° C) can be used. The pressure of the reaction depends on the selected procedure (reactor type) and is between 0.1 and 100 bar, the catalyst load (WHSV) is selected between 0.1 and 100. As a rule, you work at your own pressure (the vapor pressure of the system) or above.

The reactants can optionally be diluted with inert substances. Inert substances are preferred paraffins.

The molar ratio of aroma olefin is usually set between 1: 1 and 100: 1 (preferably 2: 1-20: 1).

Aromatic ingredients

All aromatic hydrocarbons of the formula Ar-R are possible, where Ar is a monocyclic or bicyclic aromatic hydrocarbon radical and R from H, C _1-5 -alkyl, preferably C _1-3 -alkyl, OH, OR etc., preferably H or C-ι _-3 alkyl is selected. Benzene and toluene are preferred.

Stage e)

In stage e), the alkyl aromatic compounds obtained in stage d) are sulfonated and neutralized to alkylarylsulfonates.

The alkylaryls are through

1) sulfonation (for example with SO ₃ , oleum, chlorosulfonic acid, etc., preferably with S0 ₃ ) and 2) neutralization (for example with Na, K, NH ₄ , Mg compounds, preferably with Na compounds)

converted to alkylarylsulfonates. Sulfonation and neutralization are adequately described in the literature and are carried out according to the prior art. The sulfonation is preferably carried out in a falling film reactor, but can also be carried out in a stirred tank. Sulfonation with SO ₃ is preferable to sulfonation with oleum. mixtures

The compounds prepared by the processes described above are either further processed as such, or previously mixed with linear alkylarylene and then sent for further processing. In order to simplify this process, it may also be expedient to mix the raw materials used for the production of the other alkylaryls mentioned above directly with the raw materials of the present process and then to carry out the process according to the invention. For example, as described, it is useful to mix slightly branched olefin streams from the process according to the invention with linear olefins. Mixtures of alkyl aryl sulfonic acids or alkyl aryl sulfonates can also be used. The blends are always made with a view to optimizing the product quality of the surfactants made from the alkylaryl.

In step e), linear alkylbenzenes can also be added before the sulfonation. Their amount is 0 to 60% by weight, preferably 0 to 50% by weight, in particular 0 to 30% by weight. If no low boiler removal is carried out in stage c) and no linear compounds are added in stages d) and f), the minimum amount is 5% by weight, preferably 10% by weight. Reference is made to the above explanations regarding the total amount of linear compounds added. In the linear alkylbenzenes, the chain length of the alkyl radicals preferably corresponds to the chain length of the alkyl radicals as obtained from step c) in the alkylaromatic compounds. Linear (C ₁₀ alkyl) benzenes are preferably added to (C ₁₀ alkyl) benzenes, corresponding to linear (C _{1 2} alkyl) benzenes corresponding to (C ₁ -C ₂ alkyl) benzenes.

An exemplary overview of alkylation, sulfonation, neutralization is given e.g. "Alkylarylsulfonates: History, Manufacture, Analysis and Environmental Properties" in Surf. Sci. Ser. 56 (1996) Chapter 2, Marcel Dekker, New York and references contained therein.

Stage f)

In stage f), the alkylarylsulfonates contained in stage e) can additionally be mixed with linear alkylarylsulfonates. In step f), preferably 0 to 60% by weight, particularly preferably 0 to 50% by weight, in particular 0 to 30% by weight, linear alkylarylsulfonates are mixed in. Insofar as there is no removal of low boiler components in stage c) and no addition of linear compounds takes place in stages d) and e), the minimum amount is preferably 5% by weight, preferably at least 10% by weight. Reference is made to the preferred total amounts given above for the addition of linear compounds.

All weights are based on the mixtures obtained in the previous step.

The invention also relates to alkylarylsulfonates which can be obtained by a process as described above.

The alkylarylsulfonates according to the invention are preferably used as surfactants, in particular in detergents and cleaning agents. The invention also relates to a washing and cleaning agent containing alkylarylsulfonates, as described above, in addition to conventional ingredients.

Non-exclusive examples of common ingredients of the washing and cleaning agents according to the invention are e.g. listed in WO 02/44114 and WO 02/14266.

Claims

claims

1. Process for the preparation of alkylaryl compounds

a) reacting a C 1 -C 4 -olefin mixture on a metathesis catalyst to produce a 2-pentene-containing C 1 -C olefin mixture and, if appropriate, separating off the Cφ.s-olefin mixture,

c) dimerization of C obtained in step b) after separation _4-8 - olefin mixture in the presence of a dimerization catalyst to give a C _8- i ₆ olefins containing mixture, separating the C ι ₆ -olefins and if appropriate removal _8- a partial stream thereof,

d) reacting the C _8-16 olefin mixtures obtained in stage c) or the substream with an aromatic hydrocarbon in the presence of an alkylation catalyst to form alkylaromatic compounds, with 0 to 60% by weight, based on the C _8- i ₆ olefin mixtures obtained in stage c) can be added to linear olefins,

e) optionally sulfonation of the alkyl aromatic compounds obtained in stage d) and neutralization to alkylarylsulfonates, it being possible to add 0 to 60% by weight, based on the alkyl aromatic compounds obtained in stage d), of linear alkyl benzenes before the sulfonation, if no addition has been made in stage d),

Levels d) and e) have taken place.

2. The method according to claim 1, characterized in that in at least one of steps d), e) and f) 5 to 60 wt .-%, each based on the mixtures obtained in the previous step, the linear compounds are added and the sum of the additions is not more than 80% by weight.

3. The method according to claim 1 or 2, characterized in that the metathesis catalyst in step a) is selected from compounds of a metal from group Vlb, Vllb of VIII. Subgroup of the periodic table of the elements, and / or that in step b) a dimerization catalyst uses, which contains at least one element of subgroup VIII of the Periodic Table of the Elements.

4. The method according to any one of claims 1 to 3, characterized in that the dimer-olefin mixtures obtained in stage b) have an average degree of branching in the range from 1 to 2.5.

5. The method according to any one of claims 1 to 4, characterized in that the C _4-8 olefin mixture passed in step c) 0 to 10 mol% butenes, 10 to

Contains 40 mole% pentenes, 60 to 80 mole% hexenes, 5 to 30 mole% heptenes and 0 to 15 mole% octenes, the total amount of which is 100 mole%.

6. The method according to any one of claims 1 to 5, characterized in that the C ^ - ₁₆ olefin mixture passed in stage d) or the partial stream less than 5 mol% C _<10 olefins, 5 to 15 mol% Cι Contains _0- olefins, 35 to 55 mol% of Cn-olefins, 25 to 45 mol% of C ₁₂ olefins, 5 to 15 mol% of C ₃ olefins. And less than 5 mol% of C _> ₃ olefins the total amount of which is 100 mol%.

7. The method according to any one of claims 1 to 6, characterized in that an alkylation catalyst is used in step c), which leads to alkyl aromatic compounds which have 1 to 3 carbon atoms in the alkyl radical with an H / C index of 1.

8. alkylaryls and alkylarylsulfonates obtainable by a process according to any one of claims 1 to 7.

9. Use of alkylarylsulfonates according to claim 8 as surfactants.

10. washing and cleaning agents containing, in addition to conventional ingredients, alkylarylsulfonates according to claim 8.