CA1178623A - LINEAR .alpha. OLEFIN PRODUCTION USING A TANK GROWTH REACTOR - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
A method for preparing C4 to C10 .alpha.-olefins employing trialkyl aluminum compounds, in a growth zone having a recirculation rate through an external heat transfer zone such that the contents of the zone are recirculated in a period of time sufficient to remove the heat of the reaction using added lower .alpha.-olefins at 100-150°C, 1.5-13.9 MPa, and 5-90 minute contact time followed by displacement with lower .alpha.-olefins in a static mixer zone to free the growth .alpha.-olefins and regenerate the trialkyl aluminum compounds. The growth .alpha.-olefins are separated with all of the lower .alpha.-olefins recycled to the growth and displacement steps.

29,373A-F

Description

78~Z;3 LINEAR ALPHA OLEFIN PRODUCTION
USING A TANK GROWTH REACTOR

The production of alpha olefins having un-branched carbon skeletal configurations and terminal unsaturation has been practiced for many years. With the advent of the triorganometallic compounds, viz.
triethyl and tri~n-butyl aluminum, large scale commercial production has occurred. The primary and desired products are the Cl 2 to Cl 8 ~-ole~ins for detergent use and the Cl0~ for synthetic lubrican-ts. The lower carbon atom compounds, viz. C6 to C8 have recently found utiliky in the polymer field and thus are being recovered in increasiny volume.

In U.S. Pat~nt ~,314,090, there :is (lisclosed a proce~s which provides :~or the productoIl of increased amounts o~ C~WCt0 alpha ole~ins using an elollgated coil growth reactor such as well kno~m from U.S. 2,971,969.
However, khese reactors require an olefin:aluminum alkyl ratio of about 10 to 1 for best results.

It has been found that by using a tank reactor with a relat.i~ely rapid external recirculation rate it is possible to use 2 to 6 moles of olefin per mole of 29,373A-F

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aluminum alkyl and achie~fe yields o:E the desired hexene-1 and octene-l after -the displacemen-t reaction which is as high as the system using coil reactors. An added advantage of -the present invention is the reduction in the amount of energy and capital equipment cos-ts re~uired by using the lower ratios of olefin. In fact, no excess olefin is required thereby eliminating costly recycle compression.

The growth promoting conditions used in the tank reactor are a -temperature of 100 to 150C and preferably 115 to 125C, a pressure range from 1.5-13.9 MPa and preferably 2.2-10.5 MPa and a liquid residence time of 15 to 60 minutes and preferably 30 to 40 minutes.

The growth reaction zone contents are re-circulated through an ex-ternal heat transfer zone at a recirculation rate such that the reaction zone contents are comple-tely recirculated for a -time sufficient to remove the heat of the reaction and maintain a sub-stantially constant temperature. Preferably the recirculation time period is 0.1 to 30.0 minutes and 0.5 to 3.0 minutes is -the most prefexred time period.

~ further aspect o:E the p~esent :inve~tlon is the u~e of a di~p:Lacement zone conta:irl:iny a st~tic mixer havin~ 3 to 30 fixed e].ernents which speeds up the d:isplacement reac-tion.

The invention is further illustrated by the Figure of the at-tached drawing.

In the dra~7ing, 10 is a feed line supplying ethylene, propylene, or bukene-1, and preferable ethy-29,373A~F -2-., .

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~t7~ 3 lene which has been suitably purified to xernove moisture and oxygen. Item 12 is a compressor wherein the lower olefin feed is brought up to a pressure of about 4.9 ~Pa.
The compressed olefin is -then fecl by line 14 to line 16 where it is combined with recycled catalyst from line 18 and circulated through -the heat exchanger 17, the pump 19 and the recycle line 21 to the reactor inlet 22.

The pressurized tank or growth reactor 20 is provided with a gaseous outlet 23 for unreacted gases which circulate via line 25 through a heat exchanger 26 and line 28 to the displacement feed line 30. The combined liquid feed from line 30 and the gas feed from line 28 are thus combined to provide a feed to the 15 displacement reactor 32. Reduction valves 24 and 27 are provided to maintain the high pressure in the reactor 20.
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~ In the displacement reactor 32, li~uid growth material is reacted with the displacement gases to generate growth ~-olefin~ o C~-C~0 and also recover the organo me-tallic catalyst. The reactor 32 is a conventional static rnixer.

The contents of the displacemeIlt reactor 32 are fed by l.inq 3~ :into the extracti.on ~olumn 36 wherein lower olefins or ethylene is stripped from the reaction mixture and is removed by outlet 42, and line 48. A
recycle line 46, condenser 44 and a recycle inlet 40 is provided to remove the heavier gases and return them as liquid reflux. The line 48 carries the lower olefins to a compressor 50 where the gases are brought back up to the proper pressure for introduction by line 52 into the recycle line 28.

- 29,373A-F -3-The ~ottoms from -the tower 36 are removed by outlet 38 and i.ntroduced by line 39 into the tower 54 by inle-t 53. In a manner similax to the tower 36, a higher olefin such as butene gas is stripped via the outlet 64, condenser 66 and inle-t 62, with line 68 removing the butene gas to a takeoff valve 70 and transfer line 72. If desired, sorne or most of the butene can be withdrawn from valve 70 for use as an intermediate. The remaining butene is thus recycled by line 72 back to line 48 for reuse as a displacing gas.

The liquid bottoms in the butene tower 54 are recirculated via outlet 56, re-boiler 58, and inlet 60.
The bottoms are fed by line 59 to inlet 74 of the vacuum tower 76 wherein the desired u-olefins (C6-Cl~) are separated from the catalyst mixture. The vacuum tower 76 is provided with a vacuum line 98 for the necessary reduction in pressure.

The bot-toms from the vacuum tower 76 are drawn off by outlet 84 and circula-ted by pump 82 through a re-boiler ~0 and back to the -tower 76 by inlet 78.

A portion of the vacuum -tower bo-t-toms are recycled by line 86 back to the grow~h reac:tor 20. A
reflux circui-t for the vacuum tower 76 is provi.cled by line 90, conctenser 92 ancl :inlet 9~. A purge line 57 is provldecl to periodically remove Cl 2 and higher molecular weight material.

The vacuum tower overhead produc-ts are re-moved by ou-tlet 88 and sent to a heat exchanger 96 and removed for further separation into the desired ~-olefins.

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In accordance with the present in-vention, a lower olefin such as e-thylene after being pressu.rized to a range from 2.2-7.0 MPa is fed to a -tank reactor maintained a-t a pressure of from 1.5-13.9 MPa and preferably from 2.2-10.5 MPa and a tempera-ture of 100C
to 150C and preferably from 115C to 125C wherein the olefin reacts with a trialkyl aluminum growth material, .
viz. triethyl aluminum or -tributyl aluminum and preerably ~:
a mixture of the two, high in triethyl aluminum conten-t.
The reactor is of such size to enable the reactants to be in contact between 5 and 90 minutes and preferably from 30 to 40 minutes. Due to the exothermic reaction, the pressurized tank reactor is provided with an external heat transfer device so that the reaction zone contents : 15 are compIetely recirculated in a period of time from 0.25 to 5 minutes and pre~erably 0.5 to 3 minutes.
Product withdrawn from the growth reactor is cooled -to insure the growth products and any unreacted grow-th material remain in the liquid state yet the olefin or ethylene which has no-t reacted can be separa-ted and returned -to the growth reactor as recycle olefin.

The cooled li~uid growth product and any unreacted growth material is then mixed w:it:h a dis-placement gas, ~uch as ~-ole~in of 2~4 ca.rbon atoms or pre:erabl.~ a mixture o:f ethylene and butene-l in a stat:ic m:ixer clisplclcement reactor o such s:ize as to displace the material :Eed in under six seconds. The displacement gas is preheatecl to a temperakure such that when mixed with the liquid feed stream at the displacement reactor, the temperature will be in the range from 200C to 350C and preferably in the range from 250C to 280C. The reactor pressure is maintained at 0.1-7.0 MPa ancl preferably in -the range from 29,373A-F ~5-.:

-6~
~ 17~3K2:3 0.79-1.48 MPa. The static mixer has 3 to 30 elements and preferably 6 to 12 elements so -that a relatively shor-t contact time in the ranye from 0.1 -to 5 seconds, and is preferably in the range from 0.5 to 1.0 seconds, is achieved with complete mixing of the yas and liquid.
The mol ratio of the displacement gas to each alkyl group of the trialkyl aluminum is in the range from 10:1 to 50:1 and preferably in the range 25:1 to 30:1.

The displacement product, the olefins and the tri lower alkyl aluminum product, is rapidly cooled to below about 150C and fed to the first stage of a separator 36 wherein the displacement gas and the ole~ins are removed and sent -to a second stage separator 54 and the liquid product remaining is directed to a third stage separator 76. The gaseous products de-livered to the second stage separator are further cooled and the displacement gases, removed, recom-pressed, heated, and recycled to -the displacement reactor feed stream. The liquid bo-t-toms pradwct from the second separation is the desired olefins, in -this case C~ to C10 ~olefins, which may be further separa-ted in its constituent components. The third separator strips any remaining ~-olefins from the tri lower alkyl aluminum growth ma-terial which olefins are combirled with the ~-ole~lns from the s~concl separator and the latter, the lower a:Lkyl aluminwm compounds are recycled to the growth reactox.

Illustrative of the effectiveness of -the tank reaction zone with recirculation~ the conditions and results of thirteen typical exa~ples are shown below wherein all percentages are in weight percent.

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~'7 Example 1 A 250 cc tank reactor was charged with -the following materials:

triethyl aluminum (TEA) 17.07 gms tri-n-butyl aluminum (TNBA) 11.38 gms tetradecane (n-Cl~) 28.45 gms This represents a 50% by weight aluminum alkyl feed s-tream.

The reactor had a bottom outlet connected to a recycle pump which pumped the reactor contents through a cooling coil back into the reactor.

~ total of 31.8 grams of ethylene gas was charged at 4.9 MPa~ The reactor was brought to a 126aC
operating temperature via electric tape heaters. The pump was started and set to flow 50 cc/min. of li~uid.
This represents a 1 1/2 minute reactor volume turnover.
, The reaction was allowed to run ~or 30 minutes and then cooled down to room temperature. The aluminum alkyls were collected and a material baLan~e was done, The aluminum alky.ls, when slowly hydro:Lyzed, showed kh~
followiny oLefin yields:

Butene-l 22.0% wt.
Hexene-l 58.7% w-t.
Octene-l 16.6% wt.
Decene-l 2.~% wt.
Cl2+ 0.1% wto _ Total 100.0% wt.

29,373A-F -7 ., ' Example 2 -Using the same reactor set up as Example No.
1, -the following conditions were noted:

Charge TEA 11.4 gms TNBA 7.6 gms n-Cl4 76.0 gms The solution recycle rate was set at 50 cc/min. with the reactor operating at 4.9 MPa and 113C. A total of 35.3 grams of ethylene was charged to the reactor during the reactor operation.

After 30 minutes residence time, the follow-ing yields were no-ted:
,.
Butene-l 8.9% wt.
15Hexene-l 61.3% wt.
Octene-l 23.7% wt.
Decene-l 5.8% wt.
.~ 0.3% wt.

Example 3 Using the same reactor set up as ~xampl~ No.
1, the following conditions were noted:

Char~e triethyl aluminum (TEA) 28.5 grams tri n-butyl aluminum (TNBA) 19.0 grams tetradecene (n-Cl4) 47.5 grams The solution recycle rate was set at 50 cc/min. This represents a 2.5 minute reactor volume , 29,373A-F ~8-: . . ' :

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-turnover. A total 27.8 ~ram~ ethylene gas was charged with the reactor operating at 4.9 MPa and 117C for 20 minutes residence time.

The following yields were no-ted:

Butene-l18.9% wt.
Hexene-l66.9% wt.
Octene-l13.0% wt.
Cl2+ 0.0% wt.

: Example 4 10 Using the same reactor set up as Example No.
1, the ~ollowing conditions were noted:

Charge TEA 16.9 grams TNBA 11.3 grams n-Cl~28.2 grams .

The solukion recycle rate was se-t at 75 cc/min. This represenks a 1.0 mi,nute re~ctor volume turnover. A to~al 3Z.2 grams ekhylene yas WrlS ChclrC3ed with the r~ac:tor oper,ltirlg at 4.9 MPa ancl.l20C or 30 minutes r~sidence t:Lme.

The following yields were no-ted:

Butene-l 19.6% wt.
Eexene-l 57.4% wt.
' Octene-l 18.5% wt.
Decene-l 4.0% w-t.
Cl2+ 0.5 wt.

29,373A-F -9-~10--~17~~;~3 Example S
~ sing the same reac-tor set up as Examp].e No.
1, -the following conditions were noted:

Charge TEA 17.0 grams TNBA 11.3 grarns n-Cl~ 28.4 grams The solution recycle rate was set at 50 cc/min. This represents a 1.5 minute reac-tor volume turnover. A total 19.8 grams ethylene gas was charged with the reactor operating at 3.6 MPa and 120C for 30 minutes residence time.

The following yields were noted:

Butene-l 22.2~ wt.
Hexene-l 57.6% wt.
Octene-l 16.2% wt, Decéne~l 3.5% wt.
Cl2~ 0.5% wt.

Exam~ 6 Using the sarne rea~tor set up as Example No.
:l, the ~ollowlng conditiorls were notecl:

Charge , TEA 16.8 grams TNBA 11.2 grams n-CI~ 28.0 grams 29,373A-F -10-, ' . ' ' '~ ~ ' .

~ ~7~Z3 The solu-tion recycle rate was se-t at 50 cc/min. Th:Ls represen-ts a 1.5 minute reactox volume turnover. A total 29.8 grams ethylene gas was ch~rged with the reac-tor operating at 4.9 MPa and 110C for 30 minutes residence time.

The following yields were noted:
,, Butene~l 22.23% wt.
Hexene-l 60.11% wt.
Octene-l 15.0% wt.
Decene-l 2.34% wt.
Cl2+ 0.32% wt.

Example 7 Using the same reactor set up as Example No.
1, the following conditions were noted:

TEA 5.7 grams TNBA 3.8 grams n-Cl~ 85.3 grams The solution recycle rate was set at 50 cc/min. This represents a 2.S mlnute reactor volume turnov~r. A total 31.S grclms ethylene gas was Gharged with the reactor operating at 4.9 MPa and 115C for 30 minutes residence time.

29,373A-F

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The following yields werei noted:

Butene-l 16.9% w-t.
Hexene-l 60.8% wt.
Octene-l 17.6% wt. -S Decene-l 3.g% wt.
Cl2+ 0.8% wt.

Example 8 Using the same reactor set up as Example No.
1, the following conditions were noted:

10 ~ Charge ,:
TEA 11.4 grams TNBA 7.6 grams n-Cl~ 76.0 grams ; The solution recycle rate was set at 50 cc/min. This represents a 2.5 minute reactor volume turnover. A total 35.3 grams ethylene gas was charged with the reactor operatlng at 4.9 MPa and 113C for 30 minutes residence time.

The followin~ y:ields were noted:

Butene-l 8.8% wt.
Hexene~l 61.3% wt.
Octene-l 23.6~ wt.
Decene-l 5.8% wt.
Cl2+ 0.S% ~7t.

29,373A F -12-:

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~ ~7~ 3 ~xarnple 9 Using the same reactor sek up as Example Mo.
1, the following conditions werë noted:

Charge TEA 17.0 grams TNBA 11.3 grams n-Cl 4 28.4 grams The solution recycle rate was set at 50 cc/min. Th1s represents a 1.5 minute reactor volume turnover. A total 39.0 grams ethylene gas was charged with -the reactor operating at 6.3 MPa and 121C for 30 minutes residence tlme.

The followlng yields were noted:

Butene-l 4.3% wt.
Hexene~1 56.2% wt.
Octene-1 26.7% wt.
Decene-1 9.8% wt.
C12~. 3.0% wt.

le 10 _ Using the same reactor set up as E,xarnple No.
1, the followiny conditions were noted:

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TEA 22.68 yrams TNBA 15.12 grams n-C1 4 37.80 grams 29,373A-F -13~

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The solukion recycle rate was set at 67 cc/min. This represents a 1,5 minut~ reactor volume turnover. A total of 45~3 grams ethylene gas was charged with the reactor operating at 4.9 MPa and 130C
for 15 minutes residence -time, The following yields were noted:
' , Butene-l 24.2% wt.
Hexene-l 55.3% w~. :
: : Octene-l 16.4% wt.
Decene-l 3.5%:wt.
+ 0.6% wt.

Example 11 Using khe same reactor set up as Example No.
1, the following conditions were noted:
:
~: 15 'charge TEA 22.68 grams TNBA 15.12 ~rams n-CI~ 37.80 grams The solu-tion recyclè rate was set at 67 cc/min. This repre~ents a 1.5 minute reactor volume turnover. A total of 45.3 grclms ethylene CJaS was chaxyed with the reactor operating at 4.9 MPa and 1.30C
for 30 minut,es residence time.

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The followiny yields were no-ted:

~utene-l 21.2~ wt.
Hexene-l 53.2% wt.
Octene-l 19.8% wt.
Decene-l 5.0% wt.
Cl2~ 0.9% wt.

Example 12 Using the same reactor set up as Example No.
1, the following conditions were noted:

Charge TEA 17.04 grams TNBA 11.36 grams n-Cl 4 28.40 grams The solution recycle rate was se-t at 50 cc/min. This represents a 1.5 rninu-te reactor volume turnover. A total of 12.5 yrams ethylene gas was charged with the reactor operatin~ at 2.2 MPa and 120C
for 30 minutes residence time.

The following yields were noted:

Butene~l 19.7% wt.
Hexene-l 75.4% Wt.
Octene-l 4.9% wt.
~ecene-l 0.0% wt.
Cl2+ 0.0% wt.

29,373A-F -15-3~ 3 Example 13 Using -the same reactor se-t up as Example No.
1, the following conditions were noted:

TEA 17.07 grams TNBA 11.38 gr~ms n~cl4 28.45 grams The solution recycle rate was set a-t 50 cc/min. This represents a 1.5 minute reactor volume turnover. A total of 67.2 grams ethylene gas was charged with the reactor operating at 10.5 MPa and 120C for 30 minutes residence time.
~.
The following yields were noted:

Butene-l 13.3% w-t.
Hexene-l 58.14% wt.
Octene-l 22.43% wt.
: Decene-l 5.4% wt.
~12~ 0.73% w~.

29,373A-F -16-, . :

Claims (10)

Claims

1. In a process for making C4-C10 .alpha.-olefins wherein an .alpha.-olefin having 2-4 carbon atoms or mixtures thereof and low molecular weight trialkyl aluminum are reacted in a growth reaction zone under growth promoting conditions to provide higher molecular weight trialkyl aluminum and reacting an .alpha.-olefin having 2-4 carbon atoms or mixtures thereof with said higher trialkyl aluminum in a displacement reactor zone under displace-ment conditions to provide a mixture of C4-C10 .alpha.-olefins, the improvement which comprises providing a growth reaction zone by reacting 2 to 6 moles of .alpha.-olefin per mole of trialkyl aluminum in a tank reaction zone and having a recirculation rate through an external heat transfer zone such that the reaction zone contents are completely recirculated in a period of time sufficient to remove the heat of said reaction zone and maintain a substantially constant temperature therein.

2. The process as set forth in Claim 1 wherein the recirculation time is 0.1 to 30.0 minutes.

3. The process as set forth in Claim 1 wherein the recirculation time is 0.5 to 3.0 minutes.

4. The process as set forth in Claim 1 wherein the growth promoting conditions are a temperature 29,373A-F -17-of 100 to 140°C, a pressure of 1.5 to 13.9 MPa, and a liquid residence time from 15 to 45 minutes.

5. The process as set forth in Claim 1 wherein the growth promoting conditions are a temperature of 115 to 125°C, a pressure of 2.2 to 10.5 MPa, and a liquid residence time from 30 to 40 minutes.

6. A process for making C4-C10 .alpha.-olefins which comprises A) reacting 2 to 6 moles of an .alpha.-olefin having 2-4 carbon atoms or mixtures thereof per mol of trialkyl aluminum in a tank reaction zone under a pressure of 1.5 to 13.9 MPa and a temperature in the range from 100°C to 150°C wherein said zone has a recirculation rate through an external heat transfer zone such that the contents thereof are recirculated in a period of time sufficient to remove the heat of said reaction zone so as to maintain a substantially constant tem-perature therein and to provide a growth product comprising higher trialkyl aluminum, B) reacting an .alpha.-olefin having 2-4 carbon atoms, or mixtures thereof with said growth product in a displacement zone having a temperature in the range from 200°C to 350°C, a pressure in the range from 0.1 to 7.0 MPa and a contact time in the range from 0.1 to 5 seconds, and C) recovering the C4-C10 .alpha.-olefins.

29,373A-F -18-

7. A process for making C4-C10 .alpha.-olefins which comprises A) reacting 2 to 6 moles of ethylene per mol of trialkyl aluminum in a tank reaction zone under a pressure of 1.5-13.9 MPa and a temperature in the range from 100°C to 150°C wherein said zone has a recirculation rate through an external heat transfer zone such that the contents thereof are recirculated in a period of time from 0.5 to 3 minutes to provide a growth product comprising higher trialkyl aluminum, B) reacting ethylene or butene-1 or mixtures thereof with said growth product in a displacement-zone having a temperature in the range from 200°C to 350°C, a pressure in the range from 0.1 to 7.0 MPa and a contact time in the range from 0.1 to 5 seconds, and C) recovering the C4-C10 .alpha.-olefins.

8. The process as set forth in Claim 7 wherein said displacement zone comprises a static mixer zone.

9. The process as set forth in Claim 8 wherein said static mixer zone has 3 to 30 fixed elements.

10. The process as set forth in Claim 7 wherein the tank reaction zone is under a pressure of 2.2 to 10.5 MPa and has a temperature in the range from 115° to 125°C and the displacement zone is under a pressure of 0.8 to 1.5 MPa and has a temperature in the range from 250° to 280°C.

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