DE1618703B1 - Process for the preparation of aromatically substituted alkanes - Google Patents

Description

3 4

less than 15% · The reduction in the content of at very low temperature and / or under pressure the 2-aryl isomers is in most cases to be carried out in practice, it is possible to obtain a material as large as that which can be achieved if one with only 4 carbon atoms, such as η-butane or cyclo starting olefin, to use a separate isomerization butane. On the other hand, it is possible to subject Paverfahren. The content of 2-aryl isomers in 5 raffins with up to about 32 carbon atoms, such as. B. the product is about the same as that used under petroleum waxes, although in some cases use of a pure olefin material can prevent problems using such materials containing only the isomer which is evident in the solubility and recovery of the double bond is in a central location. They kick. It is preferred to use a paraffin material with addition of the paraffin with about 4 to about 32 carbon atoms to 15 carbon atoms, such as n-hexane, substance atoms does not lead to an increase in the cyclohexane, n-heptane or n-dodecane.
travel costs. The paraffin is added to the reaction vessel. Within certain limits, the amount of paraffin used has an influence on the amount of 2-aryl and, since the paraffin is not consumed in the reaction, alkanes in the alkylation product. In the process, it can be conveniently recovered in the distillation. In the invention it is necessary to recover at least 5 and reapply. The process percent by weight of paraffin of the invention therefore does not require the use of an additional alkene reactant. By process step and not a substantial amount ir- a relatively large reduction in the 2-arylalkane content as an additional raw material. of the reaction product is a paraffin

Each paraffin material can be used appropriately at 20, up to about 50 percent by weight, the method of the invention can be used. One can based on the weight of the alkene reaction portion therefore a straight-chain paraffin, a branched paraffin, is. If anything, it is rarely upstream Paraffin or a cycloparaffin alone or in part, the paraffin material in such an amount Use mixture together. Straight chain paraffins to use that weight ratio of paraffins and unsubstituted cycloparaffins are preferred to α-alkene is more than about 10: 1, since the admitted because the presence of a secondary or ter- use of more than this amount of paraffin no tiary carbon atom in the paraffin its react- corresponding reduction in the 2-arylalkane content tion ability increased in the presence of HF and under the product results and the handling greater unfavorable conditions result in undesirable minor amounts of materials the cost of the product and the can lead to reactions. Increase the choice between paraffin recovery. But apart from that chain paraffins and unsubstituted cycloparaf- one of these disadvantages is the addition of larger superfines largely depends on what shots available in terms of paraffin is not detrimental. Is satisfied; in some cases the boiling point also plays a role or results can still be obtained the solubility of the paraffin in the reactants using a weight ratio of paraffins a role in the choice. It is advisable to use an immaterial alkene of about 50: 1. In the To choose paraffin material with a boiling point, in most cases the preferred amount of paraffin is different of that of the aromatic reactant material at about 100 to 1000 percent by weight and of those normally in the added by weight of the alkene reactant reaction product isomers present, so that mers, or in other words a weight ratio Paraffin material easily by distilling back paraffin to α-alkene from about 1: 1 to 10: 1. can be won. According to a preferred embodiment of the Veruch be chosen so that it is easy in the crude process of the invention the paraffin material in material mixture and also in the individual reaction two parts divided, and a first part of the same is Participants is soluble, so that the formation of a joint with at least a portion of the aromatic Reaktrennen Paraffin phase is avoided. This latter 45 participant, e.g. B. 10 to 100% of the same and the Reconsideration is not really a problem as almost the desired amount of HF catalyst is mixed. Of the all paraffin materials with the ordinary alkene- second part of the paraffin material is then with the nen and aromatic hydrocarbons, which in the alkene reactants and optionally the Method of the invention used, miscible remainder of the aromatic reactant mixed, are. 50 The two mixtures are then mixed, preferably

The chain length or number of carbon atoms wise, stirring constantly, to get the chance in the paraffin material there is little or no local concentration of reagents and a This is important as long as the paraffin material has the desired, undesired temperature gradient within the reactants has physical properties because, as above, tion mixture has to be avoided. Usually it is carried out, the paraffin normally in the reaction 55 expedient that the two parts of the paraffin material tion mixture is inert and after the end of the Um- are approximately the same and that if the paraffin material settlement is recovered unchanged. In the eye, the greater part is divided into unequal parts think one should choose a paraffin, which a mixture containing a catalyst is given before Has a boiling point that is at least as high as that of the α-alkene is mixed with it. Preferably the highest reaction temperature to be used, but 60 to about 40 to 90 percent by weight of the paraffin not so high that the paraffin is not added from the high-catalyst-containing mixture; to boil However, boiler residues from distillation can also produce satisfactory results which can be won. Similarly adding 100% or some other percentage selected a paraffin with a chain length whose boiling point of the paraffin to the catalyst mixture obtained that of the unconverted raw materials as long as the catalyst mixture is a paraffin rial and each of the desired isomers of the range containing about 5 percent by weight of the duct is different to allow recovery of the alkene reactant at the time of mixing Paraffin material to facilitate. If the reaction is the same as the alkene reactant.

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The method of the invention cannot obtain optimal results for production, and such

virtually any arylalkane can be used, so this will work in most cases

then in the usual way for the production of super- not expedient. The preferred amount of catalyst

surface-active cleaning agents are used. This corresponds to a weight ratio of catalyst aromatic hydrocarbon, the most common at 5 to 1: 2 to total olefin reactants

the manufacture of detergent intermediates 10: 1.

used is benzene; But it can also be The temperature at which the method of the invention

whose monocyclic aromatic hydrocarbons formation is carried out is conventional and Hegt

such as toluene, xylene or cumene can be used. Any between the freezing point of the reaction mixture the aliphatic hydrocarbon substituent group and about 200 ° C; the preferred working temperature

The pen on aromatic nuclei should be saturated, to is between about -10 and 80 ° C, especially about

To prevent side reactions and also should be -5 to 60 ° C. A change in the working temperature

there are no longer three substituents. In most cases, in most cases the

Cases the aromatic will not contain more than about 9 carbo-2-arylalkane fractions in the product, with low reactant atoms contain, although this limitation 15 tion temperatures smaller amounts of 2-arylalkene

more of the availability and convenience to favor isomeric. For example, a

Use in the manufacture of detergents- lowering the temperature from 55 to 0 ° C a,

Depends on intermediates; the invention can be based on the total weight of the product, 7- to

aromatic reactants are carried out 8% reduction in the 2-phenyl isomers. those that contain no more than 15 carbon atoms. 20 The pressure under which the alkylation reaction

Straight-chain α-olefins, which are carried out in, can be suitable within a wide range of processes according to the invention, as long as the pressure used is not so low in the conventional manner that evaporation is possible materials used for raw painting of detergent intermediates or an excessive loss of catalyst, i.e. olefins with 8 to 24 carbon atoms, 25 occurs. Suitable working pressures are between about -olefins with a molecular chain length of 0.5 and 10 at, the preferred pressure range of 10 to 20 carbon atoms being preferred. varies between about 1 and 4 at. The commercially available olefins are usually gel The invention is mixed by the following examples and not pure materials; such Ge is explained in which all parts, unless otherwise stated mixed with average molecular chain 30, are parts by weight, lengths within the above ranges are in the
Method of the invention used. example 1

In practicing the comparative experiment of the invention, it is usually advantageous to use a molar ratio of the aromatic reactants 35, a mixture of 200 parts benzene and 200 parts, to the «-olefin of at least 1: 1, because anhydrous HF is converted into a suitable one Alkylied the use of lower ratios given to the circulation apparatus, and heated to 55 ° C under a pressure of excessive formation of high-boiling secondary prop- 2.8 atu; at a temperature of ducts. As for the upper limit of the molar encryption 55 ⁰ C, the pressure must be at least about 2.8 atm gehältnisses of the aromatic compound to the "-Öle- 40 will hold to avoid catalyst losses fin is concerned, only considerations are herein with respect A mixture 100 parts of α-dodecene and 100 parts of the simplicity and economy of the len benzene is then added with constant stirring in recovery of unreacted raw materials within 10 minutes, and the reactance is decisive; Therefore, even such a high conversion mixture can be kept at 55 ° C for 45 minutes with constant stirring. The mixture will then be appropriately used at such as 100: 1. The 6 ° C cooled, left to stand for 1 hour and the preferred aromatic-to-olefin ratio between the layer then see from the catalyst layer by IVa ^ l ^u od 10: 1. The change in ratio- decanting separated. The separated organic nisses of the aromatic compound to the -olefin layer is then distilled in order to remove unreacted in most cases no noticeable influence on benzene and dissolved HF catalyst, the 2-arylalkane content of the product, but then an Sample of the product purified in this way in the usual way, the nature and amount of the by-products generated by vapor phase chromatography. determine the isomer distribution.

The amount of catalyst to be used is in

of the usual order of magnitude and can range from about 55 attempt A 10 percent by weight, based on the weight of the

Alkenmaterials in the reaction mixture, up to a The above comparative experiment is repeated, upper limit, which is only determined by the purpose of only that 800 parts by weight of η-hexane to the mixture moderation; you can z. B. under HF and benzene and 200 parts by weight of η-hexane to achieve satisfactory results, use a catalyst amount given to the mixture of «-dodecene and benzene, which is a weight ratio of.
Gives a 20: 1 total olefin catalyst. An experiment B small amount of catalyst, such as. B. only 0.2 percent by weight, based on the total weight of the react- The above experiment A is repeated, only tion mixture, so that a separate catalyst- 65 that instead of a weight ratio of paraffin to phase is not obtained, is also applicable. An olefin of 10: 1 and a weight ratio of 50: 1 results in a noticeable reduction in the 2-aryl alkane isomer content of the product; however, the following results were obtained:

Comparison test (no n-hexane)

Attempt a Attempt B n-hexane; n-hexane; P: O = 10: 1 P: O = 50; 1 13.7 13.9 15.1 16.1 16.2 18.1 55.0 52.0

2-phenyldodecane

3-phenyldodecane

4-phenyldodecane

5- and 6-phenyldodecane

Note: P = paraffin, O = olefin.

For comparison purposes, benzene was also alkylated with dodecene-6; it was possible to reduce the 2-phenyldodecane content of the product to 13.6% (14.8% if no n-hexane was used). Through this the process of this invention is shown to involve the use of pure olefins or of Mixtures of α-olefins and olefins with the double bond inside the chain makes possible and leads to results that were previously in a one-step process were only obtainable using pure olefin in which the double bond is centrally located in of the aliphatic chain.

B is ρ ie 1 2 _a5

The experiments A and B of Example 1 were repeated, except that a reaction temperature been used from 0 to 5 ⁰ C instead of a reaction temperature of 55 ° C.

When the above procedures were tested, the following results were obtained:

n-hexane;
P: O = 10: 1

2-phenyldodecane

3-phenyldodecane

4-phenyldodecane

5- and 6-phenyldodecane

12.0
13.7
19.8
54.5

n-hexane;
P: O = 50: 1

11.4
14.0
18.6
56.0

35

40

45

When the results obtained in Example 1 are compared with those of Example 2, it can be seen that in Using lower reaction temperatures improved results can be obtained.

Example 3
Comparative experiment

A mixture of 200 parts by weight of benzene and about 200 parts of anhydrous HF is placed in a suitable alkylation device and placed under Aufrecht-25.2
16.9
17.4
40.6

maintaining a pressure of 2.8 atü to ensure the presence of a liquid HF phase, heated to 55 ° C. A mixture containing 25 parts of α-dodecane, 25 parts of α-tetradecene, 25 parts of α-hexadecene, 25 parts of α-octadecene and 100 parts by weight of benzene is then added to the catalyst mixture over a period of about 10 minutes with constant stirring. The stirring is then continued for at least 10 more minutes and the mixture is ^{cooled to 6 °} C. and left to stand for 1 hour. The organic layer is then separated and distilled to remove unreacted benzene and dissolved HF catalyst. A sample of the product so purified is then analyzed by vapor phase chromatography in order to determine the isomer distribution of the various alkylbenzenes.

Attempt a

An alkylation reaction is carried out practically as described in the comparative experiment, only that to the catalyst mixture before the initiation of the reaction 800 parts by weight of n-hexane and to the 200 parts by weight of n-hexane are added to the olefin benzene mixture before the reaction is initiated.

When testing the above procedures, the isomer distributions of the phenyldodecanes were in the products practically the same as given in Example 1; the isomer distributions of the other phenylalkanes were as follows:

isomer

2-phenyl 3-phenyl 4-phenyl 5-phenyl residue

Comparative experiment C ₁₆ C ₁₈ attempt C ₁₆ no n-hexane 32.4 31.4 n-hexane train 11.6 C ₁₁ 12.5 14.7 C ₁₄ 11.3 24.4 7.3 8.4 11.9 11.7 15.3 13.7 13.3 47.8 45.5 13.5 65.4 13.5 33.5 59.9

11.8 9.1 8.3

70.8

109 586/402

Claims (2)

1 2 Even when using hydrogen fluoride as a catalyst, the content of the 2-arylalkane isomers is not reduced in a satisfactory manner. 1. Process for the production of aromatic Also in the process of the USA patent specification substituted alkanes with a low Ge 5,3387,056 becomes a hydrogen fluoride catalyst system stop at 2-aryl isomers by alkylating mo- applied. This patent can be seen that Nocyclic aromatics with not more than 15 Koh- a lower content of 2-arylalkane isomers achieved fuel atoms and in which the aromatic nucleus becomes, if one is a catalyst modifier no more than three alkyl substituents are used, but this is a separate production step «-Olefins with 8 to 24, especially with 10 to 10 requires and increases the total cost because the Mon-20 Carbon atoms, is consumed in the reaction in the presence of a fluorinated diffusing agent, hydrogen as a catalyst at temperatures of However, the content of 2-arylalkane isomers -10 to 80 ° C, especially from -5 to 60 ° C, which is still too high. characterized in that it is also from US Pat. No. 3,509,225 Alkylation in the presence of a paraffin with about 15 known that one at a slightly lower level 4 to about 32, preferably with 5 to 15 carbons of 2-arylalkane isomers, if one catastrophe atoms performs, with the amount of the in the lysatormodiffenmittel applies and also Paraffins present in the reaction mixture use min-chlorinated paraffins. The content of 2-aryl residue However, despite the application, 5 percent by weight, based on the gel isomer weight of the α-olefin, is but not more than the 20 of the modifier and the chlorinated parafolubility of the paraffin in the organic phase fine more than 20% · The state of the art is thus of the reaction mixture and not over a range that the use of a catalyst weight ratio from paraffin to «-olefin from about modifier is required when using the 50: 1. Content of 2-arylalkane isomers to an acceptable 2. The method according to claim 1, characterized by a marked value, d. H. less than 30%. Exceptional, that the weight ratio of paraffin should either be separate chlorination stages to «-olefin is about 1: 1 to 10: 1. Paraffins are used or should be used as starting materials and then used to generate Olefins are dehydrated, which in turn are then used 30 alkylation of aromatic compounds The invention relates to a method of manufacture. With the known methods, that is Development of arylalkanes with a low content of with the additional process steps or with the It is not isomers in which the aromatic substituent will work in catalyst modifiers 2-position on the alkyl chain. succeeded in reducing the content of 2-aryl isomers to less It is known to lower sulfonates of arylalkanes from 35 than 15 ° _0. straight-chain alkenes different properties The aim of the invention is now to provide a process for depending on the position of the aromatic substitution of aromatically substituted alkanes with tuenten to the aliphatic group. a low content of 2-aryl isomers available For most applications in the field of supply in which (1) it is not necessary to have surface activity, it is expedient to use arylalkanes to 4 ° additional catalyst modifiers which contain relatively small amounts of or chlorination of paraffins isomers in which the aromatic men or any other ^ additional process substituent is in the 2-position of the alkyl chain. If there is a double bond in the starting alkene, but there is still a considerable reduction in the center of the aliphatic chain, the content of 2-aryl isomers is achieved and an alkylation product is conveniently obtained (3) there are no additional costs,
The invention therefore relates to a method for producing in which the aromatic group is in the vicinity of aromatically substituted alkanes with one end of the alkyl chain. If the result is a low content of 2-aryl isomers due to gangalkene but a straight-chain α-olefin, the 5 ° alkylation of monocyclic aromatics with non-alkylation product normally has a content of more than 15 carbon atoms and in those of the aroisomers in which the 2-position of the alkyl group matical nucleus is not more than three alkyl substituents aromatically substituted, which is so high that it contributes with -olefins with 8 to 24, especially with 10 to Product for the manufacture of detergents less than 20 carbon atoms, in the presence from Fluorwasserger is suitable. 55 substance as a catalyst at temperatures from -10 to Numerous processes are known to convert from 80 ° C, especially from -5 to 60 ° C, «-Olefinen Arylalkanprodukte with low amounts is characterized that one the alkylation in the presence to produce 2-arylalkane isomers, but despite a paraffin with about 4 to about 32, preferably the use of additional process steps to carry out with 5 to 15 carbon atoms, the a 2-arylalkane isomer content of about 20 to 30% ^6o amount of the paraffin present in the reaction mixture to lead. fins at least 5 percent by weight, based on the From the method of US Pat. No. 3,349,144, the weight of the -olefin is, but not more than, it is known to use paraffins to produce mono-solubility of paraffin in the organic phase of the olefins to undergo a dehydrogenation process and not more than a weight fen and the monoolefins for the alkylation is then an aroma ratio of paraffin to -olefin of about 50: 1, matic connections to use. The content of 2-aryl isomers in the according to the the olefins initially obtained represent a mixture, the aromatic drive obtained according to the invention leads to a high content of 2-arylalkane isomers. substituted alkanes is surprisingly