DE1238026B - Process for the production of aluminum trialkyls - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

Int. CL:

C07f

GERMAN

PATENT OFFICE

PATENT LETTERING

German KL: 12 ο - 26/03

Number:

File number:

Registration date:

1 238 026
E29015IVb / 12 ο
March 31, 1965
April 6, 1967
October 19, 1967

Display day:

Issue date:

The patent specification corresponds to the patent specification

The invention relates to a process for the production of aluminum trialkyls by at least one build-up reaction from trialkyl aluminum and ethylene, treating a portion of the build-up reaction product in a displacement reaction with an olefin mixture containing predominantly lower olefins, and another part of the build-up reaction product with an olefin mixture which contains predominantly higher olefins, with those from the displacement reactions originating olefins into lower and higher olefins ίο divided and fed back to the displacement reactions in the circuit.

It is known that lower aluminum trialkyls in higher aluminum trialkyls by reaction with Ethylene can be transferred. This creates mixtures of compounds with statistical Distribution of chain length. Such mixtures are possible for the production of olefins or alcohols lent uniform molecular weight not suitable.

Isolation of compounds of uniform alkyl group length is practically impossible because Alkyl aluminum compounds that have 6 or more carbons in each alkyl group because of the high required temperatures and the resulting disintegration as well as because of the readjustment of the statistical equilibrium cannot be distilled. . ,

Another problem is the occurrence of side reactions. At the increased working temperatures The byproducts of the build-up reaction are oleefins, especially vinyl olefins and vinylidene and Internal olefins formed. The latter are not susceptible to conversion to straight chain alkyl aluminum groups accessible.

To date, aluminum trialkyls have been used through a number of displacement and build-up reactions of recycled olefins, which are then separated according to molecular weight or Chain length were subjected to manufactured. There are remarkable olefin losses, especially as Interior and vinylidene olefin.

In contrast, the method according to the invention is characterized in that to remove the Vinylidene and internal olefins a part of the fraction containing higher olefins with a trialkylaluminum, the ^ -branched alkyl groups, is subjected to a displacement reaction and the unreacted olefins obtained, including the vinylidene and internal olefins, as well as the olefins originating from this displacement reaction are removed from the cycle.

So far in the description of the expression »alkyl process for the production of
Aluminum trialkylene

Patented for:

Ethyl Corporation, Baton Rouge, La. (V. St. A.)

Representative:

Dipl.-Chem. Dr. rer. nat. W. Berg
and Dipl.-Ing. O. Stapf, patent attorneys,
Munich 2, Hilblestr. 20th

Named as inventor:

Wayne Thomas Davis,

Charles Leo Kingrea, Baton Rouge, La.

(V. St. A.)

Claimed priority:

V. St. v. America March 31, 1964 (356 148)

aluminum parts «, are to be understood ^{as meaning 1} J ₃ atom equivalent of aluminum carrying a single alkyl group, also referred to as RaI, where" R "is an alkyl group" al " ¹ I _{3 atom equivalent of aluminum.} "Trialkylaluminum" is to be understood as meaning not only compounds such as trihexylaluminium, but also diethylaluminum hydride and dihexylethylaluminum. The hydride groups quickly convert to alkyl groups in the presence of olefins. The aluminum trialkyls used according to the invention usually have only small proportions of hydride groups. ^r

The lower olefins can also contain smaller amounts of higher constituents, the heavy or high Olefins contain minor amounts of low molecular weight olefins.

Vinyl olefins are straight-chain -olefins with a terminal ethylenic bond, vinylidene olefins those with ß- branching, z. B. 2-methyl-1-pentene, and internal olefins, those olefins that are not - «- olefins.

The process according to the invention comprises at least one build-up reaction and at least two displacement reactions, the separation of the olefins emerging from the displacement reactions and fractionation of the olefin mixture into one essentially of lower and one essentially of higher Fraction consisting of olefins. It then follows with at least part of the heavy olefin fraction

709 696/381

3 4

the claimed displacement reaction, whereby a gas-liquid separator is separated and the

actually the vinyl olefins recycled from the non-vinyl recycled.

olefins are separated. The non-vinyl olefins The displacement reaction in reactor 159 is carried out from the process in an amount which corresponds to the low olefins produced by 173 in a considerable excess of at least approximately the amount of carbon produced during the reaction, the amount of coal being withdrawn, while the vinyl - mean carbon number is selectively converted to alkyl radicals between the middle carbon fins. number of alkyl groups of the desired trialkyl

According to a preferred embodiment, the aluminum compound and the lower alkyl charge

two build-up reactions are used, the first being kung.

Build-up reaction with a lower trialkylaluminum io The displacement reaction is at fairly high,

charge and the second with an intermediate product leading to secondary reactions through temperatures

Alkyl trialkyl aluminum feed fed from a. The reaction will mostly take place at 288 to 330 ° C

first displacement reaction originates, works. accomplished. The ratio of olefin to Al-Ver

According to a further embodiment, additional binding can, for. B. about 1 mole per alkyl group

lent for treatment according to the invention heavier 15 to 10 mol. The second displacement

Olefins At least some of the light olefins in a reaction 166 are preferred in a ratio of 2 to 5: 1.

appropriate treatment, if necessary added together. Mostly it is in a single phase system, above

with the heavier olefins, d. H. So worked in a mixture, the critical conditions. The olefins

subject. can be preheated and the reaction of the

In the context of the invention, it is also possible to use a mixture of essentially adiabatic supplements Displacement reaction, preferably carried out under conditions within a few seconds Use of ethylene as a displacement olefin, and are.

carry out an additional build-up reaction in order to remove the heavier alkyl-

by forming additional vinyl olefins at least groups are formed by those from the olefin feed

partially replaced the loss by the undesired 25 originating.

Compensate for olefins. The outflow from the first displacement

The inventive solution of the exhaust reactor 159 becomes the separation zone 161 via 160

Separation or _% cleaning problem was directed. The separation of the aluminum trialkyls from

Much greater freedom of movement in the selection of the olefins is achieved through several rapid distillations

the exchange reaction conditions allows. 30 mostly carried out at decreasing pressures in order to

In Fig. 1, the basic process according to the invention is shown as diagrammatically as possible all of the olefins via the overhead, including a line 163 to be withdrawn. The bottom products are fed back to the build-up reactor 151, displacement reactor 159, 166, via 154 into the build-up reaction stages, an olefin fractionation section 172 and a parallel displacement and separation cleaning section 178. Subordinate treatment is carried out on the other part of the add-on equipment parts such as valves, pumps, Causes heater and waste products. This part is above 158 the exchangers are not shown. second displacement reactor 166 fed. The ethylene is carried out via 152 and a lower trialkyl action is carried out with heavy olefins supplied in excess of 168 aluminum or a trialkylalkylaluminum hydride. These olefins mixture fed via 153. For example, the lower alkyl aluminum may have an intermediate carbon number feed may have a pure product such as 10, 12 or 14, depending on the product desired, triethyl aluminum, tripropyl aluminum, tributyl.

be aluminum or a mixture that generally The effluent flows via 167 into the separating lower alkyl groups, such as a mixture of zone 160. The olefins are overhead via 170 C ₂ - to C ₀ -alkyl groups. In addition, intermediate 45 can be discharged and the desired aluminum product - trialkylaluminum - compounds can be withdrawn in hydro-trialkyl over 170 "at the bottom.

selnder amount and composition 154 supplied to the olefins separation zones 161, 169 are

will. Often times, the mean carbon content is about 163, 170 and 171 in fractionation zone 172

Alkyl groups in this charge were carried out about half as large. In practice this is

as the average carbon number of the alkyl groups 50 several fractionation columns. At least one

of the end product. Part of the lower ones withdrawn overhead over 173

In the build-up reaction, a plurality of mol of olefins are converted as olefin feed for the displacing ethylene per mole of trialkylaluminum. The supply reactor 159 used. Correspondingly, the conditions of the build-up reaction can be far removed from heavy olefins at 174 and change over 168 range. So the pressures of 105.5 55 can be fed to the second displacement reactor,
to 210.9 kg / cm ² and temperatures of about A portion of the olefins withdrawn above 174 will be above 121 to 143 ° C. A single point 175 sent to the purification zone 178, which structure 177 can be provided with a plurality of reaction also trialkylaluminum whose alkyl group be who least predominantly / 5-branched, z. B. Triiso-

The build-up product does not contain, among other things, 60 butyl aluminum, loaded.

converted ethylene as well as secondary reactions. In the cleaning zone 178 , the vinyl olefins

formed olefins with more than 2 carbon atoms. . reacted with the trialkylaluminum, the

The main amounts of the building reaction products olefins correspond to the previous alkyl groups

are fed to the displacement reaction, which releases and the vinyl olefins to form the

at least one tenth up to nine tenths, usually a 65 corresponding alkylaluminum compound bound

Third up to two thirds, the first to be displaced. The vinylidene and internal olefins of the

reactor 159 can be fed through 157 through 155. The olefin feed runs essentially unchanged

excess ethylene is for the most part due to. A typical composition of an olefin

feed is about 20 mole percent internal olefins, 10 mole percent vinylidene olefins and 70 mole percent vinyl olefins.

The conversion of the vinyl olefins to form alkyl aluminum compounds enables efficient separation in separation zone 180 . The effluent contains olefins derived from the trialkylaluminum reactant, unreacted olefins consisting of the interior and vinylidene olefins which are withdrawn via 181 , and alkyl aluminum compounds which are withdrawn via 183 . These latter compounds are mostly within the desired molecular weight range and can be introduced into 184 .

In a preferred embodiment, two build-up reactions are used instead of the one build-up reaction the F i g. 1 carried out. Next is an additional build-up and ethylene displacement reaction intended. Finally, the purification is extended to at least some of the lower olefins.

These embodiments are shown schematically by FIG. 2 explained. A first build-up reactor 11 is provided with a feed 13 for the aluminum trialkyl. The ethylene required for the build-up reaction is fed in via 12.

The aluminum trialky build-up product of the first build-up reaction 11 is fed to the displacement reactor 23 via 17. Its amount can be increased by circulating trialkylaluminum over 51. At the same time, preferably preheated olefins above 35, which have a lower carbon number than the alkyl groups of the trialkylaluminum mixture in the reactor 23, are fed to the displacement reactor 23.

The olefins withdrawn from the displacement reaction at 22 are passed through 25 into the fractionation zone 29 introduced. Feed 28 to fractionation zone 29 also contains olefins 60 from another displacement reaction described below. It can of course be separate Fractionation trains can be used to fractionate these two olefin mixtures.

A second build-up reactor 45 is charged with ethylene via 46 and with trialkylaluminum which is fed in and circulated via 44. This trialkylaluminum feed contains from separation zone 24 via 26 compounds withdrawn and, if desired, trialkylaluminum fed via 43 which is derived from the purification of the lower olefins described below.

The products of the second build-up reaction 45 withdrawn via 52 are in the displacement reactor 54 with originating from the fractionation zone 29, implemented over 53 fed olefins, these olefins predominantly proportions of higher Olefins contain such a molecular weight or carbon number as are necessary for the alkyl groups of the Trialkylaluminum are desirable. The products emerging from the displacement reactor 54 via 56 are separated in the separation zone 57 into olefins 60, which are fed to the fractionation zone 29 and into the desired final trialkylaluminum product withdrawn through 62. If desired, The separation 57 can be a partial or total conversion of the alkyl groups to the corresponding ones Include aluminum alkoxides as this facilitates separation.

From the fractionation zone 29, lower olefin is withdrawn via 32 overhead. The main part is fed via 35 in the circuit to the displacement reactor 23, but a part is fed continuously via 31 to a selective displacement reactor 36. The reactor 38 is simultaneously charged with a trialkylaluminum serving as a reactant. The more than 40 products emerging from the selective displacement reaction are transferred to the separation stage 39

ίο fed for separation into 41 withdrawn unreacted olefins and 42 withdrawn displaced olefins. The trialkylaluminum is preferably returned to the main process via 43 and is added to the feed to the second build-up reactor 45. Optionally, some or all of the lower olefin passed through 31 and originating from the fractionation zone 29 can be transferred through 30 a for the recovery of normal olefins into the main process, which is used to recover normal or vinyl olefins from higher olefins.

At least some of the higher olefins are withdrawn from fractionation zone 29 via 79. One part is charged via 80 to a selective displacement reactor 81 for reaction with a trialkylaluminum introduced via 82 and serving as a reactant. The products withdrawn from this selective reaction over 70 are subjected to a separation into unreacted or displaced olefins withdrawn via 87 and 88 and a mixture of trialkylaluminum compounds withdrawn via 89, which was formed during the reaction and which is preferably with those withdrawn via 62 end product combined to form the total product withdrawn over 75,

example 1

In the working example below, the process for making aluminum trialkyls is described with a high proportion of tridecyl to trihexadecyl

aluminum from triethylaluminum and ethylene described. The procedure according to FIG. 2 used.

Fresh triethylaluminum is passed through 13 in the first build-up reactor 11. Ethylene is introduced through 12 in a ratio of well over 4.5 moles per alkylaluminum group.

The build-up reactor is operated at a temperature of approximately 143 to 149 ^° C. and a pressure of approximately 175.8 kg / cm ² . A typical composition of the alkyl aluminum components of the effluent from reactor 11 is as follows:

Alkyl aluminum components mole percent

Butyl and lower 6

Hexyl 11

Octyl 17

Decyl 19th

Dodecyl 17

Tetradecyl 13

Hexadecyl 8

Octadecyl and higher 8+

The above aluminum trialkyl mixture, that of some olefins formed by side reactions is accompanied, is via 17 the displacement reactor23, together with some additional aluminum trialkyl introduced via 51.

i 238

In the displacement reactor 23, the reaction takes place with a lower olefin, which by the Line 35 is fed. A typical composition of the olefin is the following:

Olefin mole percent

Butene _:. 9

Witches 21

Octene 32

Decene 38

Dodecenes ■ <1

The displacement reactor is operated at about 299 ° C and about 42.2 kg / cm ² . Olefin is introduced in a large excess of about 7 moles per alkyl aluminum group, preheated to provide essentially all of the heat requirements of the adiabatic reaction. The displacement reaction leads to an aluminum trialkyl enriched _{in C 0} -C _{10 -alkyl groups.} The olefin of the effluent is enriched in higher olefins, ie of 12 and more carbon atoms.

A typical composition of the olefins of effluent 22 from positive displacement reactor 23 is:

Olefin mole percent

Butene 9

Witches 19

Octene 30

Decen 35

Dodecene 3

Tetradecene 2

Hexadecene 1

Octadecene and higher 0.7

35

Alkyl radicals mole percent

Butyl and lower 4

Hexyl 8

Octyl 16

Decyl 23

Dodecyl 22

Tetradecyl 14

Hexadecyl ·. 7th

Octadecyl and higher 5

The alkyl aluminum identified above accounts for up to about three quarters of the total effluent with the remainder being olefins. These are used in substantial excess, approximately 8 to 9 moles per mole of trialkylaluminum. The positive displacement reactor operates at a temperature of about 299 ° C and a pressure of about 17.6 kg / cm ² .

The displacement reaction leads to aluminum urntrialkylenes with alkyl groups in the desired one Area. A typical effluent from the second positive displacement reactor 54 becomes olefin free as follows Have compositions:

Alkyl radicals mole percent

Ethyl 2.0

Butyl 1,2

Hexyl 2.8

Octyl 4.9

Decyl 9.6

Dodecyl 35.5

Tetradecyl 23.6

Hexadecyl 13.2

Octadecyl 6.3

Eicosyl and al 1,2

Contain the aluminum trialkyls separated off in separation zone 24 and withdrawn via 26 a high proportion of trialkylaluminum, with a typical alkylaluminum distribution being the following is: '

Alkyl radicals mole percent

Butyl and lower 17

Hexyl 21

Octyl 24

Decyl 28

Dodecyl and above 10

This product is accompanied by a minor amount of olefins that are not produced by the rapid stripping process and is combined with recovered trialkylaluminum fed via 43. This recovered product contains approximately 6% alkyl aluminum mixture from the displacement reaction.

The mixture is passed via 44 to the second build-up reactor 45. The average chain growth achieved here is noticeably below the first chain growth. Since alkyls of significantly higher molecular weight are used, lower temperatures are usually used. About 121 to 127 ^° C. and 175.8 kg / cm ^{2 are used} .

A typical composition of the trialkylaluminum at the drain 52 of the second stage 45 is:

The olefins discharged from the first displacement reaction via 25 and the olefins carried over 60 are combined in 28 and fed to the olefin fractionation zone 29. The olefin fractionation takes place in several columns for separation into products of the desired composition. The relatively light, Over 32 withdrawn products contain hexenes and some octenes and decenes.

The olefin fractionation does not separate the isomeric olefins of the same molecular weight. A proportion of unreactive isomers in the light olefins of about 20 mole percent internal and 5 mole percent vinylidene isomers is typical. Several percent of this product is diverted via 31 and reacted with trialkylaluminum supplied via 37. The triisobutyl aluminum or a correspondingly selectively reactive trialkyl aluminum is added in approximately the same molar ratios of vinyl olefin to alkyl aluminum groups. This feed contains unreacted olefins, namely internal and vinylidene olefins, as well as olefin liberated by the displacement reaction which, in the case of triisobutylaluminum, is isobutylene. Typical reaction conditions for this working method are approximately 260 ^° C., 0.35 to 3.52 kg / cm ⁸ pressure and a total reaction time of approximately 1 to 3 minutes.

The displacement reaction in 38 can be carried out by methods known per se, e.g. B. in that the mixture is based on the countercurrent principle

is brought into contact with vaporous light olefins and the liquid phase of isobutylene components freed and attracted over 41. The isobutylene can later be used for regeneration of triisobutyl aluminum can be used.

The unreacted undesired isomers Olefins are evaporated and stripped through 42 for purification. The trialkylaluminum formed approaches the composition of the trialkylaluminum from the first displacement reactor 23. The two Products are mixed over 43.

The treatment of a part of the heavy olefins to purify the undesired olefin isomers is carried out in substantially the same manner as in the above-described light olefin purification treatment. A portion of the heavy olefins from the fractionation zone 29 is passed over 80, reacted with the selectively reactive trialkylaluminum. Typical reaction conditions are about 26O ⁰ C, 0.36 kg / cm ² and a reaction time of 1 to 3 minutes. The isobutylene resulting from the displacement reaction is separated off and drawn off via 88 and the undesired isomeric olefins, namely vinylidene and internal isomers, are separated off and drawn off via 87.

In converting the aluminum product thus obtained into alcohol, an alcohol mixture is about received the following composition:

Example 2

B e i s ρ i e 1 3

In this procedure, the operations are essentially the same as in Example 1, however a special precaution is taken to change the composition of the product Distribution of the structural products originating from the reactor 45, with part of the trialkylaluminum the reaction in the first displacement reactor 23

ίο is subjected. In addition, there will be a special one Overhead light olefin fraction of fractionation zone 29 transferred to the heavy olefin purification zone for the manufacture of a product which is enriched with regard to said particular alkyl content.

In this procedure, essentially the same conditions as in Example 1 are maintained, however, approximately half of the build products in 52 are directed to 51 and with the supply to the first Displacement reactor 23 combined. In addition, an octene-rich light olefin is passed through 30a and with the Over 80 heavy olefins fed in combined with over 82 fed in to convert the vinyl components Triisobutyl aluminum.

In this way, products that are relatively rich in octylaluminum are obtained. The following table illustrates a typical analysis of these trialkylaluminum products and the trialkylaluminum products, which are created in the second displacement reactor.

Alcohol weight percent

Ethanol <1

Butanol <1

Hexanol 1.5

Octanol 3.5

Decanol 8

Dodecanol 34

Tetradecanol 26

Hexadecanol 16

Octadecanol 8.8

Eicosanol 1.9

A high yield of final product based on both the ethylene and triethylaluminum feed is received.

In the following example, the composition of the build-up product differs from that created by the method according to Example 1 in that a substantial proportion of light olefin from the Fractionation zone led into the cleaning zone of the heavy olefins and simultaneously with the more than 80 fed heavy olefins is treated.

The procedures of Example 1 are repeated with the exception that a sidestream from the olefin fractionation zone 29 is used, over 30 a, this stream being highly concentrated in octenes. These are mixed with the heavy olefins, over 80 fed, and the 1-octene is reacted with triisobutylaluminum in addition to the vinyl compounds of the heavy olefin stream. The trialkylaluminum compounds obtained contain corresponding amounts of acetylaluminum groups, and the octylalcohol concentration in the alcohols obtained therewith is increased by 4 to 7 percent by weight.

Alkyl component Product of the
second
Displacement
reactor 62
Mole percent Trialkyl
aluminum
of the
Cleaning (89)
Mole percent ethyl
Butyl
Hexyl.
Octyl
Decyl
Dodecyl
Tetradecyl
Hexadecyl
Octadecyl
Eicosyl and higher .. 3
2
4th
6th
9
39
22nd
10
4th
1 30th
21
38
20th
9 '
3
21

The more than 75 products withdrawn give, after conversion to alcohols, a product as follows Composition:

Alcohol weight percent

55

Ethanol

Butanol

Hexanol -

Octanol

Decanol

Dodecanol

Tetradecanol

Hexadecanol

Octadecanol

Eicosanol and higher

"J

39

24

14th

The products obtained according to the invention can be converted into alcohols in a known manner.

The process according to the invention allows the build-up and displacement reaction to take place at high temperatures perform. The overall speed of the reaction increases by a factor of two for about every 12 ° C, but increases with the temperature

709 696/381

temperature is the amount of olefins obtained as by-products.

Claims (2)

Patent claims: I. Process for the preparation of aluminum trialkyls by at least one building reaction from trialkylaluminum and ethylene, treating one Part of the build-up reaction product in a displacement reaction with an olefin mixture which contains predominantly lower olefins, and another part of the build-up reaction product with an olefin mixture which contains predominantly higher olefins, the olefins originating from the displacement reactions in. lower and higher olefins are divided up and fed back into the circuit for the displacement reactions, characterized in that one for removing the vinylidene and interior olefins Part of the fraction containing higher olefins with a trialkylaluminum which is / J-branched Contains alkyl groups, is subjected to a displacement reaction and the resulting not converted olefins including vinylidene and internal olefins as well as those from this displacement reaction originating olefins are removed from the cycle. 2. The method according to claim 1, characterized in that in addition also part of the fraction containing lower olefins, optionally in admixture with the part of higher olefins which Purification is subjected to the displacement reaction. 1 sheet of drawings 709 548/434 3.67 ® Bundesdruckerei Berlin