DE1793812B1 - Process for the preparation of 1- (7'-tetralyl) -4-phenylbutane - Google Patents

Description

It is known that Friedel-Crafts catalysts, such as aluminum chloride and boron trifluoride, are capable of various rearrangements and isomerizations of paraffinic and hydroaromatic hydrocarbons to catalyze.

In the publication in "Reports of the German Chemical Society", Vol. 57, 1924, p. 1990 to 2003, the use of aluminum chloride for various rearrangement and cleavage reactions described, for example for the rearrangement of tetrahydronaphthalene.

From Topciev.Zavgorodnij and P a u s k i η, "Boron trifluoride and its compounds as catalysts in organic chemistry" (Berlin 1962), p. 220 and 221, it is known that various isomerizations, especially of paraffins, with the help of boron trifluoride can be made.

The isomerization of octahydronaphthalenes with the aid of HBF4 is described in Proceedings of the Chemical Society, year 1960, p. 412, and from the DT-PS 3 33 158 it is known that by treating tetrahydronaphthalene with aluminum chloride elevated temperature hydroaromatic hydrocarbons, especially octahydroanthracene and octahydrophenanthrene, can be obtained.

It is also known that tetrahydronaphthalene in the presence of AlCh with the formation of numerous Reaction products such as sym-octahydroanthracene (OHA), sym-octahydrophenanthrene (OHP) and 1- (7'-tetralyl) -4-phenylbutane (TPB) reacts according to the following equation:

AlCl,

Tetrahydronaphthalene

OHA OHP

HHHH

ι ■■ i

Η - C - C - C - C-

, A HHH

+ t i

TPB

A disadvantage of this process for the production of OHA, OHP and TPB is that the Yields of any of these substances are low. So the yield of OHA and OHP is in the above Response generally not more than 15 to 30%. Another disadvantage is that the reaction stops runs selectively for a specific product.

In the reaction of tetrahydronaphthalene catalyzed by AlCb, for example, OHA cannot be used exclusively and manufacture OHP or not exclusively TPB.

It has now surprisingly been found that when carrying out the reaction according to the above Equation in the presence of HF-BF3 significantly better results and that the Yields are considerably higher. In addition, it was found that the reaction by using of HF-BF3 and by observing specific reaction conditions can be controlled so that 1 - (7'-Tetralyl) -4-phenylbutane can be obtained practically free of other reaction products.

The invention therefore provides a process for the preparation of l- (7'-tetralyl) -4-phenylbutane, which is characterized in that tetrahydronaphthalene is mixed with at least 1 mol of liquid hydrogen fluoride and at least 0.5 mol of boron trifluoride per mole of the starting material in - 50 to +15 ⁰ C, preferably at -20 to 0 ° C, treated for a maximum of about 30 minutes.

The 1- (7'-tetralyl) -4-phenylbutane prepared according to the invention can be converted into a by sulfonation Transfer wetting agent.

The inventive conversion of tetrahydronaphthalene into 1- (7'-tetralyl) -4-phenylbutane (TPB) is discussed in more detail below. The reaction proceeds according to the following equation:

Tetrahydronaphthalene

HHHH

■ I i I -C-C-C-C

J \ HHH TPB

In the method according to the invention, HF should be used in the liquid phase. Therefore, the pressure in the reaction vessel should be sufficient to keep the HF in the liquid phase. All boiling points given here relate to a pressure of 760 mm Hg abs., Unless otherwise stated. Normally the pressure of the BF3 (boiling point = - 101 ⁰ C) in the reaction vessel is sufficient to keep the HF in the liquid phase, unless other convenient measures are taken to ensure the use of liquid HF, such as creating a pressure in the reaction vessel z. B. by injecting nitrogen. The amount of HF used must be at least 1 mole per mole of tetrahydronaphthalene, but is preferably at least 4 moles, in particular at least 8 moles per mole of tetrahydronaphthalene. The examples below show that with

Increasing the HF: tetrahydronaphthalene ratio increases the yield of TPB, i.e. the Yield of reaction product at least up to HF: tetrahydronaphthalene molar ratios of about 10: 1 increased. The HF.-tetrahydronaphthalene molar ratio expediently exceeds this 50: 1 not, but ratios up to 200: 1 or higher can be used if necessary be applied.

The amount of BF3 must be at least 0.5 mole per mole of tetrahydronaphthalene and is preferably at least 0.7 moles per mole of tetrahydronaphthalene. Although with BF3: tetrahydronophthalene molar ratios between 0.1: 1 and 0.5: 1 some reaction product is obtained, a very rapid and drastic result Increase in yield when the ratio exceeds 0.5: 1. The BF3: tetrahydronaphthalene ratio is particularly preferably at least 1: 1. The yield of the reaction product is usually maximized at a BF3: tetrahydronaphthalene ratio between 0.5: 1 and 2.0: 1. Consequently the amount of BF3 normally used does not become two moles per mole of tetrahydronaphthalene Exceed, but amounts up to 10 mol Per mole of tetrahydronaphthalene or even larger amounts may optionally be used. That the following example shows more clearly the effect of the BF3 / tetrahydronaphthalene ratio on the yield of the reaction product.

The temperature at which the reaction is carried out has an influence on the product obtained. At temperatures ranging from -50 to +15 ⁰ C TPB is obtained in high yield with virtually complete exclusion of OHA and OHP. The preferred temperature range for the production of TPB is -20 to 0 ° C. At temperatures in the range from 15 to 110 ° C., on the other hand, OHA and OHP would be obtained with practically complete exclusion of TPB.

The example below clearly shows the dependence of the type of reaction product on the Reaction temperature.

The time it takes for the tetrahydronaphthalene and HF-BF3 to come into contact with each other can be vary considerably. For the most part, the reaction is almost instantaneous; i.e. within 1 to 2 minutes, after which the further reaction proceeds at a slower rate, up to about 90 Minutes a maximum yield of the reaction product is obtained.

If the reaction time is excessively prolonged, the amount of by-products tends to decrease formed compounds OHA and OHP is increased, so that the reaction time is appropriate Should not exceed 30 minutes.

The reaction can be carried out in a conventional manner using a conventional apparatus. For example, the tetrahydronaphthalene used as the starting material is placed in a closed reaction vessel which is equipped with means for heating and stirring. If the reaction temperature is lower than the melting point of tetrahydronaphthalene, namely -30 ⁰ C, then the tetrahydronaphthalene is preferably dissolved in an inert solvent such as hexane or heptane. The required amount of HF is then added, whereupon the HF-tetrahydronaphthalene mixture to the desired Reaction temperature is heated. The desired amount of BF3 is then added, whereupon the vessel is preferably shaken or its contents stirred in some other way in order to ensure effective contact of the HF-BF3 catalyst with the tetrahydronaphthalene. After the BF3 has been added to the reaction mass, it is then kept at the reaction temperature for the desired time. The BF3 is added after the reaction temperature has been reached because no reaction takes place until the BF3 is added. Since the products received from the. Depending on the reaction temperature, it is generally desirable that no reaction proceed until the desired temperature is reached.

After the reaction time has ended, the reaction vessel TPB, HF, BF3 contains something unreacted Tetrahydronaphthalene and a nearly negligible amount of other by-products.

The hydrofluoric acid remaining in the reaction mixture and any boron trifluoride present, the is dissolved in it can be distilled from the vessel.

However, it is desirable to remove the HF from the reaction vessel as a liquid rather than a gas. The vessel is then opened, causing most of the BF3 to be removed, and the remaining reaction mass is quenched with ice water. Two layers of liquid arise an aqueous acid layer and an organic layer. If desired, the acid can be biphasic in this System by mixing the system with Na2CO3 be neutralized. The organic layer is then decanted and washed several times with water to remove any traces of acid or traces of Na2CO3 present.

The desired reaction product, TPB, can be isolated from the organic layer, for example by distilling off under reduced pressure. At 15 mm Hg TPB distilled at about 230 to 245 ° C and at 0.3 mm Hg at about 175 to 190 ⁰ C. Optionally, the TPB can be by other known methods, such as separated by chromatography.

Example:

The reaction vessel is a 75 ml shake bomb with heating and cooling means Is provided. The bomb is purged with nitrogen and then evacuated. Then it becomes tetrahydronaphthalene and then filled HF into the bomb. Tetrahydronaphthalene was used in an amount of 0.1 Moles added; this amount was the same for all approaches. The bomb is shaken at the point you want Reaction temperature heated, and then BF3 is added. In all approaches, the BF3 pressure is sufficient to maintain essentially all of the HF in the liquid phase. The bomb then becomes the required reaction time kept at the desired reaction temperature, the reaction time of the Addition of the BF3 is appropriate. The shaking of the bomb continues throughout the reaction time continued. After the reaction time has elapsed, the bomb is cooled to 20 ° C, opened and its contents in Quenched ice. Two liquid phases arise, an aqueous acid layer and an organic layer. The two-phase system is neutralized with Na2CO3, whereupon the organic layer attracted and repeated several times with twice its volume of water is washed. The organic layer is then analyzed by vapor phase chromatography.

The organic matter remaining after using a small amount for chromatographic analysis

see layer is distilled at 0.3 mm Hg. The material passing over between 175 and 190 ^° C. is cooled. It was found to be essentially pure TPB upon analysis.
In this example three approaches were used in which the HF: tetrahydronaphthalene ratio is 10: 1 and the BF3: tetrahydronaphthalene ratio is 1.1: 1. The reaction temperatures and times are given in Table 1 together with the yield of OHA, OHP and TPB.

Table 1

HF: tetrahydronaphthalene ratio = 10: 1 BF3: tetrahydronaphthalene ratio = 1.1: 1

Approach no.

Reaction temperature ^{0 C}

Response time minutes

1
2
3

-10

5
15th
90

Tetrahydronaphthalene Conversion %

40.6 62.2 67.1 Yield%
OHA-OHP

TPB

32.0
55.9
58.7

Reaction temperature Γ C)

It can be seen from the values in this table that high yields of TPB are obtained at a relatively low reaction temperature, with essentially no OHA and OHP being formed. If one uc m Table 1 mentioned yield of TPB divided by the proportion of unreacted tetrahydronaphthalene, can be determined that the tetrahydronaphthalene, which has participated in the reaction, has been transferred to the almost theoretical yield in TPB.

Comparative experiment:

Reactive tetrahydron naphthalene
(Std.) Conversion
(o / o)

Yield (%)
OHA-OHP

25th 20th 24.5 7.8 14.5 40 20th 29.5 18.6 7.3 100 1 37.3 25.7 7.4 100 100 38.8 27.9 6.4

HF-BF3 is the AICI3 in the catalytic Conversion of tetrahydronaphthalene into OHA and OHP or TPB strongly superior. If you have tetrahydronaphthalene with AICI3 at different reaction temperatures and for different periods of time in Brings contact, the results summarized in Table 2 are obtained.

Comparing the values in Table 2 with the values in Table 1, it is apparent that HF-BF3 is far superior to AICI3 in the catalytic conversion of tetrahydronaphthalene to TPB. With With the HF-BF3 catalyst, not only are the yields of the reaction product significantly higher, but also the HF-BF3 catalyst is also far more selective.

Claims (1)

Claim: Process for the preparation of 1- (7'-tetralyl) -4-phenylbutane, characterized in that tetrahydronaphthalene is mixed with at least 1 mole of liquid hydrogen fluoride and at least 0.5 mole of boron trifluoride per mole of the starting material at -50 to + 15 ° C, preferably treated at −20 to ⁰ ° C. for a maximum of about 30 minutes.