Note: Descriptions are shown in the official language in which they were submitted.
12~660 Csse 6643(2)
PROCESS FOR THE PRODUCTION OF 2.3-DIMETHYLBUTENE-l
FROM PROPENE
The present invention relates to a proce~s for the production
of 2,3-dimethylbutene-1 (2,3-DMB-l) from propene.
It i9 known from USP 4,542,249 to produce dimethylbutenes by
(a) reacting diisobutylene and ethylene under disproportionation
conditions to produce neohexene and (b) subjecting the total
disproportionation reaction effluent containing neohexene without
separation to skeletal isomerisation to form dimethylbutenes.
It is also known to produce a mixture of 2,3-dimethylbutene
isomers, i.e. 2,3-DMB-1 and 2,3-dimethylbutene-2 (2,3-DMB-2) by the
catalytic dimerisation of propene.
Thus, USP 3,686,352 discloses a process for the production of
dimethylbutenes by dimerising in the absence of air and moisture a
propylene-containing fluid in the presence of a dimerisation
catalyst under reaction ~nditions sufficient to dimerise at least
9O percent by weight of said propylene to C6 olefins, said
dimerisation being carried out in the presence of a solvent having a
boiling point of at least 175F, isomerising the C6 olefin mixture,
separating the isomerised mixture into a methylpentene-rich stream
and a dimethylbutene-rich stream, maintaining the temperature of the
olefin mixture below 200F during the dimerisation, isomerisation
and separation steps and recycling the catalyst to the dimerisation
step. In this process no effort is made to separate the
dimethylbutenes product into its individual isomers.
The dimerisation of propene produces not only dimethylbutenes
but also methylpentenes, as demonstrated in the aforesaid USP
~96~0
3,686,352, and also hexenes. Because of their relative boiling
points it i9 difficult to separste by distillation 2,3-DMB-1 from
certain of the other dimerisation products, for example
4-methylpentene-1 (4-MP-1), 3-methylpentene-1 (3-MP-l),
cis-4-methylpentene-2 (cis-4-MP-2) and trans-4-methylpentene-2
(trans-4MP-2).
We have now devised a process for the production of 2,3-DMB-l
from propene which minimises the problem of separating 2,3-DMB-l
from other dimerisation reaction products.
Accordingly the present invention provides a process for the
production of 2,3-DMB-1 from propene which process comprises the
steps of:
(A) converting propene in one or more stages to a product
comprising 2,3-DMB-2 under conditions whereby the proportion of
2,3-DMB-2 in the product is maximised,
(B) separating 2,3-DMB-2 from the product of step (A), and
(C) contacting the 2,3-DMB-2 separated in step (B) with a catalyst
active for the isomerisation of 2,3-DMB-2 to 2,3-DMB-l under
conditions whereby 2,3-DMB-2 is isomerised to 2,3-DMB-l.
An advantage of operating in the manner according to the
invention is that lower boiling C6 olefins, 2,3-DMB-2 being the
highest boiling, can readily be distilled off, thereby leaving
2,3-DMB-2, a precursor of 2,3-DMB-1 by isomerisation.
In step (A) of the process according to the invention propene
is converted in one or more stages to a product comprising
2,3-DMB-2. The principal ob~ective in step (A) is to produce
2,3-DMB-2 at the highest achievable selectivity. This may be
accomplished in one or more stages. Thus in one stage propene may
be contacted with a dimerisation catalyst which is selective for the
production of 2,3-dimethylbutenes, preferably one which is selective
for the production of 2,3-DMB-2. Suitable dimerisation catalysts
are described in a review by B. Bogdanovic in Adv. Organometallic
Chem. 1979, 17, 105. A suitable catalyst for conversion of propene
to 2,3-DMB-2 is one based on nickel/phosphines, further details of
which may be obtained from the aforesaid review article.
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Alternatively, step (A) may be accomplished in two stages, for
example in a first staBe (i) contacting propene with a dimerisation
catalyst to produce a product comprising 2,3-DMB-1 and 2,3-DNB-2 and
in a second staBe (ii) contacting the product from stage (i) with an
isomerisation catalyst active for the isomerisation of 2,3-DMB-l to
2,3-DMB-2 under conditions which maximise the isomerisation of
2,3-DMB-1 to 2,3-DMB-2. A suitable catalyst for dimerising propene
selectively to 2,3-DMB-l in the liquid phase is nickel
acetylacetonate/tricyclohexylphosphine/ethylaluminium dichloride,
though a variety of other catalysts may be employed. A suitable
isomerisation catalyst for isomerising 2,3-DMB-1 to 2,3-DMB-2 is a
supported alkali metal, for example sodium or potassium, though
again a variety of other catalysts may be employed. Another
suitable class of isomerisation catalyst for isomerising 2,3-DMB-l
to 2,3-DMB-2 is the strongly acidic macroporous cation exchange
resins, particularly such cation exchange resins containing
sulphonic acid groups. Examples of suitable cation exchange resins
useful in the performance of the invention include Bayer Catalysts
K2631 and K2634 and Amberlyst (RTM) 15.
Step (A) may be carried out in the liquid phase or the gaseous
phase and either batchwise or continuously, the preferred mode of
operation generally being determined by the overall economics of the
process.
The temperatures a~d pre~sures to be utilised in operation of
step (A) may vary widely. The preferred conditions will largely be
determined by the mode of operation, the requirement for high
selectivity to 2,3-dimethylbutenes and the overall process
economics .
In a preferred embodiment of the present invention step (A)
comprises the stages:
(I) contacting propene in the liquid phase with a dimerisation
catalyst comprising nickel/phosphine/alkylaluminium at a
temperature in the range from -30 to +50C and a pressure in
the range from atmospheric to 25 bar to produce a product
comprising propene dimers, including 2,3-DMB-l, and higher
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boiling materials,
(II) deactivating the catalyst of sta8e (I),
(III) separating by distillation the propene dimers from high
boiling materials and catalyst re~idues from stage (II), and (IV) contacting the propene dimers separated in stage (III) in the
liquid phase with a heterogeneous isomerisation catalyst
capable of isomerising 2,3-DMB-1 to 2,3-DMB-2.
In stage (I) of the preferred embodiment the
nickel/phosphine/alkylaluminium catalyst may suitably be nickel
acetylacetonate/tricyclohexylphosphine/ethylaluminium dichloride,
though other catalysts described in the aforesaid review may be
employed. The temperature i9 preferably from -10 to +lO-C, more
preferably about O-C. The pressure i9 preferably from atmospheric
to 10 bar. Whilst it may be convenient in laboratory scale
operation of the process to operate at atmospheric pressure, in
practice commercial operation may desirably be effected at elevated
pressure in order to maintain an adequate concentration of propene
in the liquid phase.
In stage (II) the catalyst used in stage (I) is deactivated.
Deactivation of the catalyst is desirable in order to minimise or
eliminate further undesirable reactions during the separation
stages. Deactivation may suitably be accomplished by contacting the
catalyst with any material capable of decomposing or chelating with
any of the catalyst component~. Suitable materials include
anhydrous ammonia, aqueous ammonia, amines, for example alkylamines
such as triethylamine, water, aqueous strong inorganic bases, for
example sodium hydroxide or potassium hydroxide, and aqueous mineral
acids, for example dilute hydrochloric acid.
In stage (IV) it is preferred to use as the isomerisation
catalyst a strongly acidic macroporous cation exchange resin,
particularly one containing sulphonic acid groups, for example
Bayer Catalysts K2631 and K2634, or Amberlyst (~TM) 15. Before use
in the process, it is preferred to activate the resin, suitably by
drying. Drying may be achieved by a variety of methods, for example
either by heating at elevated temperature, generally about lOO-C at
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either atmospherlc or subatmospheric pressure, or by contact with a
stream of hot gas or by contact with a drying solvent.
Operation of step (A) will provide a product principally
comprising 2,3-DMB-2, together with one or more of 2,3-DMB-l,
methylpentenes and hexenes.
In step (B) of the process 2,3-DMB-2 is separated, suitably by
distillation from the product of step (A). This may be accomplished
by conventional distillation techniques. The distillation is
simplified in that 2,3-DMB-2, being the highest boiling component of
the product mixture, is readily recovered as a base fraction, the
remainder of the product being taken off as an overhead fraction.
Any overhead fraction containing 2,3-DMB-l may, if desired, be
recovered and recycled to the isomerisation stage of step (A).
In step (C) of the process the 2,3-DNB-2 separated in step (B)
is contacted with a catalyst active for the isomerisation of
2,3-DMB-2 to 2,3-DMB-l. Isomerisation of 2,3-DMB-2 will generally
produce an equilibrium mixture of the two isomers, i.e. 100%
conversion to 2,3-DMB-1 is not generally possible under normal
conditions in a single stage isomerisation.
It is preferred to use a heterogeneous catalyst in step (C),
thereby facilitating its separation from reactants and products. As
the olefin isomerisation catalysts there may be employed a supported
alkali metal catalyst, an advantage of such catalysts being that
they offer good activity at ambient and sub-ambient temperatures.
Examples of suitable alkali metals include sodium, potassium and
lithium and mixtures thereof. A preferred alkali metal is sodium.
The support may suitably be a refractory oxide, for example silica,
alumina, silica-alumina, magnesia, titania, ceria, or the like.
Metal oxides are preferred. A preferred support is alumina.
Another preferred olefin isomerisation catalyst is a strongly acidic
macroporous cation exchange resin of the type as hereinbefore
described.
The supported alkali metal catalyst may be prepared by any
conventional technique, for example by direct addition of the alkali
metal to the support at a temperature above the melting point of the
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alkali metal under an inert atmosphere. The cataiyst may suitably
comprise from O.l to 50%, preferably from 1.0 to 25Z w/w of the
alkali metal based on the weight of the support. Other preferred
catalysts are Bayer Catalysts K2631 and K2634 and Amberlyst
(RTM) 15.
A preferred catalyst for use in step (C) of the process is
a strongly acidic macroporous cation exchange resin.
Step (C) may be carried out either in the liquid phase or the
vapour phase and may be operated either batchwise or continuously,
the preferred mode of operation generally being determined by the
overall economics of the process.
The temperatures and pressures employed in step (C) may vary
widely. The preferred conditions will largely be determined by the
mode of operation, the desirability for high selectivity to
2,3-DMB-1 and the overall process economics. Generally the use of
atmospheric pressure will be found suitable. Regarding temperature,
the optimum operating temperature will depend inter alia on whether
the process is operated in the liquid phase or the vapour phase. In
the liquid phase at atmospheric pressure, for example, in order to
maximise the conversion of 2,3-DMB-2 to 2,3-DMB-l it is preferred to
operate at temperatures up to about 73-C.
The product from step (C) of the process comprises 2,3-DMB-1
and 2,3-DMB-2. The 2,3-DMB-1 may be separated and recovered from
the product by distillatian, though other methods of separation may
be employed. The product remaining after recovery of 2,3-DMB-l may
suitably be recycled to step (C) of the process. Alternatively, the
distillative recovery of 2,3-DMB-l may be incorporated into step (C)
of the process.
The process of the invention will now be further illustrated by
reference to the accompanying Figures, in which Figure 1 is a flow
diagram illustrating one embodiment of the invention and Figure 2 is
a schematic block diagram illustrating a preferred embodiment of the
invention, and by reference to the following Examples.
With reference to Figure 1, 1 is a propene dimerisation and
product work-up zone, 2 is an isomerisation zone, 3 is a 2,3-DMB-2
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recovery zone and 4 is a 2,3-DMB-2 isomerisation zone.
In operation propene and catalyst solution are fed to the
propene dimerisation unit of zone l wherein it is dimerised to a C6
product comprising 2,3-DMB-l, 2,3-DMB-2 and possibly also
methylpentenes and hexenes and Cg and higher products. In the
product work-up unit of zone 1 the C6 product is separated from Cg
and higher products and catalyst which is recycled to zone 1. The
C6 products from zone 1 are passed to the isomerisation zone
containing a heterogeneous isomerisation catalyst wherein 2,3-DMB-l
is isomerised to 2,3-DMB-2. A portion of the C6 products may,
however, be recycled to zone 1 as solvent for the catalyst. This
zone may be omitted, particularly when 2,3-DMB-2 is produced in high
selectivity in zone 1. The product from zone 2 rich in 2,3-DMB-2 is
passed to the 2,3-DMB-2 recovery zone 3 wherein other C6 products
are distilled off. The 2,3-DMB-2 remaining is passed to the
isomerisation zone 4 containing a heterogeneoùs isomerisation
catalyst wherein 2,3-DMB-2 is isomerised to 2,3-DMB-l. The
2,3-DNB-l is separated from the isomerisation product from zone 4 in
a distillation zone (not shown) and the separated 2,3-DMB-2 recycled
to zone 4. Alternatively, the distillative recovery of 2,3-DMB-l
may be incorporated into the isomerisation zone 4.
With reference to Figure 2, 5 is a propene dimerisation zone, 6
is a product work-up zone, 7 is a distillation zone, 8 is a C6
olefin isomerisation zono, 9 is a distillation zone and 10 i9 an
isomerisation zone.
In operation propene and catalyst solution are fed to the
propene dimerisation zone 5 wherein it is dimerised to a C6 product
comprising 2,3-DMB-1, 2,3-DMB-2 and possibly also methylpentenes and
hexenes and Cg and higher products. In the product work-up zone 6
the catalyst used in zone 5 is deactivated. C6 olefins are
separated by distillation from deactivated catalyst residues and Cg
and higher products in zone 7. In zone 8 the C6 product separated
in zone 7 is isomerised by contact with a heterogeneous
isomerisation catalyst to produce a 2,3-DMB-2 rich stream. In
zone 9 C6 olefins are separated by distillation from 2,3-DMB-2.
~'~79660
Finally, Ln zone 10 2,3-DMB-2 is isomerised by contact with a
heterogeneous isomerisation catalyst to 2,3-DMB-l, which is
recovered by distillation.
In the following Examples:
Example A illustrates the preparation of a lOZ (nominal loading)
sodium on alumina isomerisation catalyst.
Example B illustrates the preparation of a 3% (nominal loading)
potassium on alumina isomerisation catalyst.
Example C illustrates the activation of a Bayer Catalyst K2631 (a
cation exchange resin).
Example D illustrates the activation of an Amberlyst (RTM) 15 resin.
Example 1 illustrates propene dimerisation to 2,3-DMB-l in the
presence of a nickel
acetylacetonate/tricyclohexylphosphine/ethyaluminium
dichloride catalyst system.
Example 2 illustrates C6 olefin recovery from the dimerisation
product (composed of catalyst, propylene oligomers and C6
olefins).
Example 3 illustrates propene dimerisation in n-heptane at 0C.
Example 4 illustrates propene dimerisation in n-heptane at 10C.
Example 5 illustrates propene dimerisation in C6 olefins at 0C.
Example 6 illustrates propene dimerisation in heptane at 4.5 barB.
Example 7 illustrates distillation of the reaction product from
Example 3. `-
Example 8 illustrates isomerisation of a C6 olefin mixture over a
sodium on alumina catalyst.
Example 9 illustrates isomerisation of 2,3-DMB-l over Bayer Catalyst
K2631.
Example 10 illustrates isomerisation of a C6 olefin mixture over
Bayer Catalyst K2631.
Example 11 illustrates isomerisation of a C6 olefin mixture over
Bayer Catalyst K2634.
Example 12 illustrates isomerisation of 2,3-DMB-l over Amberlyst
(RTM) 15.
Example 13 illustrates 2,3-DMB-2 recovery from a C6 olefin mixture.
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Examples 14 to 17 illustrate the batch isomerlsation of 2,3-DMB-l
and 2,3-DMB-2 using a potasium on alumina catalyst and a sodium
on alumina catalyst.
Example 18 illustrates the effect of temperature on the
isomerisation of 2,3-DMB-2 using a sodium on alumina catalyst.
Example 19 illustrates isomerisation of 2,3-DMB-2 and recovery of
2,3-DMB-l by distillation.
Example 20 illustrates the isomerisation of 2,3-DMB-2 over Bayer
Catalyst K2631 and recovery of 2,3-DMB-1 by distillation.
CATALYST PREPARATION
Example A - 10Z Sodium on Alumina
A 3 necked 2 litre round bottom flask was fitted with a vacuum
line, nitrogen supply line, a stirrer gland and, stirrer shaft with
a stainless steel blade.
The apparatus was housed in a fluidised sand bath. The flask
was purged out with nitrogen before use.
The flask was charged with 200 g of l/ô" gamma-alumina spheres
(Norton SA6273) and heated under vacuum for 16 hours at 350-C.
Sodium metal (22 g) was then added at 350C under nitrogen with
stirring.
After 4 hours at 350C the catalyst was cooled to room
temperature and transferred to a clean, dry flask, where it was
stored until required.
Analysis of the fre~ alkali metal content was determined by
water hydrolysis and found to be 8.3% w/w Na.
Example B - 3% Potassium on Alumina
As described in Example A except 100 g of 300-500 um particle
size gamma-alumina 11.1 g of potassium were used. The catalyst thus
formed and was then diluted with a further 200 g of 300-500 um
particle size gamma-alumina. The free alkali metal content was
found to be 3.0X w/w R.
CATALYST ACTIVATION
Example C
Bayer Catalyst K2631 (a cation exchange resin) was dried at
105C/600 mm Hg for 17 hours.
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Example D
Amberlyst (RTM) 15 (a cation exchange resin) was dried at
105C/600 mm Hg for 17 hours.
Exam~le I
A 5 necked flanged 600 ml round bottom flask reactor was fitted
with a low-pressure propene supply line, a thermowell with
thermometer, a small pressure-equalised dropping funnel, rubber
septum cap, and a mechanical agitator. The reactor was housed in a
stirred cooling bath. The apparatus was purged with dry nitrogen
before use.
3.9 ml of a 0.02 M solution of nickel
acetylacetonate/tricyclohexylphosphine (1:1 molar ratio) in toluene
and 74 ml of n-heptane were added to the reactor. The solution was
then cooled to -10C. A 0.95 M n-heptane solution of ethyl
aluminium dichloride (2.0 ml) was adted via the dropping funnel at
the same time as propene was passed through the reaction mixture.
After the addition was complete the temperature was brought to 0C
and kept at this temperature for 210 minutes with continuous
addition of propene. The reaction was terminated by the addition of
anhydrous ammonia followed by the addition of 50 ml of 1.0 M aqueous
sodium hydroxide.
Samples from the reactor were removed every 30 minutes, via the
rubber septum cap, and shaken with a solution of sodium hydroxide.
The reaction product samples were analysed by gas-liquid
chromatography.
The maximum observed conversion of propene was 10.5 Kg. hr.-
(g of Ni)-l with a selectivity to C6's of 72Z, of which 63% were
2,3-dimethylbutenes. The maximum observed productivity to
2,3-dimethylbutenes was 4.6 kgh-l (g of Ni)-l at a 2,3-DMB-l to
2,3-DMB-2 ratio of 63:1.
ExamPle 2
The procedure was as that described in Example 1 except that
after 210 minutes the propene supply was stopped and the mixture
cooled to -10C. The cooled funnel was then removed and a seven
plate 1 inch Oldershaw column with still head, thermometer,
lz7g66o
ll
condenser and distillate collecting flasks were fitted. The reactor
was then heated up to 98-C (base temperature) and the fraction
between 58 and 73C (distillation head temperature) was collected.
Analysis of the distilled product (78.2 g) showed that 92Z of
the C6 olefins produced in the dimerisation reaction had been
collected overhead.
Example 3
A 5-necked flanged 20 litre flask reactor was fitted with low
pressure propene and nitrogen supply lines, a thermocouple, rubber
septum cap, a vent outlet and a mechanical agitator. The reactor
was placed in a cooling bath and the apparatus was purged with dry
nitrogen before use. The reactor was cooled to -15-C and heptane
(4.0 litres) and a 1.0 M solution of ethyl aluminium dichloride
(0.07 litres) were charged to the reactor. The mixture was then
saturated with propene and a 0.02 M solution (0.209 litres) of
nickel acetylacetonate and tricyclohexylphosphine in toluene was
added with stirring.
As the reaction started the propene flow was increased to meet
the reaction demand and the pressure in the flask was maintained at
0.3 barg. The initial exotherm was used to raise the temperature of
the reactor to 0C, which was then maintained at 0C I 2C during
the course of the reaction.
After 7 hours the reaction was terminated by the gradual
addition of water (0.003 litras) to the flask at between 0 and 5C.
Analysis of the reaction mixture by gas-liquid chromatography
showed it to contain 26% of 2,3-DMB-1 and 2,3-DMB-2. Selectivity to
2,3-DMB-1 and 2,3-DNB-2 was 55Z based on propene. The productivity
to 2,3-dimethylbutenes was 1.04 Kgh-l (g of Ni)-l.
Example 4
The procedure of Example 3 was repeated except that (i) a
reaction temperature of +10C was used and (ii) the reaction was
terminated after 3 hours.
Analysis of the reaction mixture showed it to contain 21.6X
2,3-DMB-1 and 2,3-DMB-2. Selectivity to 2,3-DMB-1 and 2,3-DNB-2 was
50% based on propene.
12
Example 5
The procedure of Example 3 was repeatet except that (i) a C6
olefin mlxture (1.0 litres) was used in place of heptane, (ii) 0.040
instead of 0.070 litres of a 1.0 M solution of ethyl aluminium
dichloride in heptane was used and (iii) 0.078 instead of
0.209 litres of a 0.02 M solution of nickel acetylacetonate and
tricyclohexylphosphine in toluene was used.
Analysis of the reaction mixture showed it to contain 32.4Z
2,3-DMB-1 and 2,3-DMB-2. Selectivity to 2,3-DMB-1 and 2,3-DMB-2 was
47% based on propene. The productivity to 2,3-dimethylbutenes was
1.44 Kgh-l (B of Ni)-l.
Example 6
A 1 litre autoclave was cooled to -5C, charged with n-heptane
(100 ml) and a l.OM solution (2.7 ml) ethyl aluminium dichloride in
heptane, under propene. The autoclave was then charged with a 0.02M
solution (5.4 ml) of nickel acetylacetonate and
tricyclohexylphosphine (1:1 molar ratio) in toluene. Propene was
then added at 4.5 barg and the reaction was maintained at 8C + 2C
for 2 hours.
Analysis of the reaction mixture by gas-liquid chromatography
showed it to contain circa 34% 2,3-DMB-1 and 2,3-DMB-2. Selectivity
to 2,3-DMB-1 and 2,3-DMB-2 was circa 46% based on propene. The
productivity to 2,3-dimethylbutenes was circa 16 Kgh-l (g of Ni)-l.
ExamPle 7 ~
A reaction mixture (2.909 Kg, prepared as for Example 3) was
distilled using a 40 plate 1 inch Oldershaw column. The column was
initially maintained at total reflux for 3 hours and then product
was taken off at a reflux ratio of 1:1 (approximate rate of take off
was 1.0 litres hour~l). The distillation was continued until all
the C6 components had been removed from the distillation column
kettle.
The fractions were combined to give a C6 olefin fraction
(1.969 kg) and a residue fraction (0.700 kg) which included the
distillation column kettle residues. Mass accountability was 92%
with a 78~ recovery of C6 olefins in the combined distilled
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13
fractions.
Exam~le 8
Two portions of 1.5 g of 25% sodium on alumina catalyst (Norton
SA6273 alumina) were mixed under argon with an approximately equal
volume of olefin mixture (3 ml) comprising 32% C6's with initial
composition shown in Table 1. One portion was kept at 0C for 10
minutes the other at ca 15~C and analysed after 10 minutes and 2
days.
TABLE 1
Olefin Initial 10 mins 10 mins 2 days
(X of C6) Concentrations at 0C at ca 15C at ca 15C
4-MP-1 0.5 2.5 0.8
2,3-DMB-1 70.8 58.5 21.8 4.0
Cis-4-MP-2 11.3 7.1 2.9 0.3
Trans-4-MP-2 5.7 8.9 13.8 1.9
2-MP-1 6.4 7.3 0.8 2.3
Cis-Hexene-3 _ 0.2 0.5 0.6
2-MP-2 1.2 4.8 7.1 21.1
Trans-Hexene-2 1.6 1.5 1.6 1.7
Cis-Hexene-2 1.3 1.0 0.6 0.4
2,3-DMB-2 1.2 13.2 49.9 67.7
In the Table the following abbreviations are used:
4-MP-1 - 4-methypentene-1,
2,3-DMB-1 - 2,3-dimethylbutene-1
Cis-4-MP-2 - cis-4-methylpentene-2,
Trans-4-MP-2 - trans-4-methylpentene-2,
2-MP-1 - 2-methylpentene-1,
2-MP-2 - 2-methylpentene-2
2,3-DMB-2 - 2,3-dimethylbutene-2
Exam~le 9
2,3-DMB-1 (20 g) was placed into a 50 ml flask fitted with a
reflux condenser and rubber septum and maintained under a nitrogen
atmosphere. The flask was heated to 40C and Bayer Catalyst K2631
(0.20 g) activated according to Example C was added. Samples were
taken at regular intervals and analysed by gas-liquid
chromatography. Table 2 shows the results obtained.
14
Example 10
The procedure of Example 9 was repeated except that a mixture
of 2,3-DMB-1 (48.1X w/w), t-4MP-2 (11.2X), 2-MP-1 (3.5Z), 2-MP-2
(22.2%), t-hexene-2 (4.4%) and 2,3-DMB-2 (10.5%) was used in place
of 2,3-DMB-1 and the reaction temperature was 50C. Table 3 shows
the results obtained.
Example 11
A reactor (of 10:1 length to diameter ratio) was packed with
Bayer catalyst K2634 (16.7 ml). A feed containing a mixture of
propene dimers was passed over the catalyst at a flow rate of
334 ml/hour at 50C. Analysis of the feed and product streams is
shown in Table 4.
Example 12
The procedure of Example 9 was repeated except that instead of
the Bayer Catalyst K2631 resin there was used Amberlyst (RTM) 15
resin activated according to the procedure of Example D.
Table 2 shows the results obtained.
Table 2
20Sample Ti=-
(seconds) 2,3-DMB-1 (%) 2,3-DMB-1 (%)
Example 9 Example 12
1 0 92.5 92.4
2 420 81.5
3 600- _ 81.8
4 1200 68.0 73.0
1620 61.2
6 1800 _ 65.2
7 2340 52.1
8 2400 _ 58.3
9 3000 _ 52.2
3600 _ 47.3
35 11 3960 38.1 _
12 4680 32.6
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TABLE 3
Time 2,3-DMB-1 t-4-MP-2 2-MP-1 2-MP-2 t-HEX-2 2,3-DMB-2 Highers
5 (seconds)
0 48.1 11.2 3.5 22.2 4.4 10.5 0.1
1440 15.9 11.2 3.4 22.2 4.5 42.7 0.1
4920 7.5 11.2 3.3 22.5 3.9 51.1 0.5
8220 5.8 11.4 3.3 22.5 3.7 52.5 0.8
1011820 5.5 11.3 3.3 21.9 4.0 52.6 1.4
15420 5.4 11.0 3.2 21.9 3.7 53.5 1.3
19020 5.5 11.2 3.2 21.2 3.3 52.9 1.7
20820 5.4 11.0 3.1 21.4 4.0 53.6 1.5
1524420 5.5 11.1 3.1 2~.2 3.8 52.9 2.4
2,3-DMB-1 - 2,3-dimethylbutene-1
T-4-MP-2 - Trans-4-methylpentene-2
2-MP-1 ~ 2-methylpentene-1
2-MP-2 - 2-methylpentene-2
t-HEX-2 - Trans-hexene-2
2,3-DMB-2 - 2,3-dimethylbutene-2
TABLE 4
Component Feed % w/w Product Z w/w
4-methylpentene-1 1.0 1.0
2,3-dimethylbutene-1 ) 39.2 9.1
cis-4-methylpentene-2 )
trans-4-methylpentene-2 21.4 21.5
2-methylpentene-1 4.0 2.3
cis-hexene-3 1.0 1.0
2-methylpentene-2 3.5 3.5
trans-hexene-2 13.5 14.9
cis-hexene-2 0.9 0.9
2,3-dimethylbutene-2 13.5 43.7
Heptane 2.0 2.0
1 ~79660
16
Example 13
Batch distillation of 628 g of a C6 olefin mixture ~wt %
composition: 4MP-1,1.1; 2,3-DMB-2~Cis 4-MP-2, 16.2; trans 4NP-2,
8.9;4MP-l/hexene-1,2.2; hexene-3, 0.4;2MP-2, 25.6; trans
hexene-2,1.2; Ci9 hexene-2,0.2; 2,3-DMB-2,44.0) was carried out on a
1 inch 40 plate Oldershaw column with a 2 litre kettle. The lower
boiling olefins (4MPl, 2,3-DMBl, c-4MP2, t4MP2, hexene-l and 2MP1)
were removed with a reflux ratio set at 20:1 which was slowly
increased to 40:1 resulting in very little loss of 2,3-DMB-2 in the
distillate. The 2MP2 was removed with a reflux ratio set at 60:1.
Overall, this gave 90% recovery of the 2,3-DMB-2 (kettle product)
with purity of 99.0%. The major impurities were cis-hexene-2 less
than 0.1Z, 2MP2 0.5X, trans-hexene-2 0.2% and cis-hexene-2 0.2Z.
Examples 14 to 17
Portions of sodium or potassium on alumina were mixed and
shaken under an inert atmosphere with small volumes of 2,3-DMB-l or
2,3-DMB-2. The results obtained are shown in Table 5.
Isomerisation of 2,3-DMB-l produced an exothermic reaction in both
cases.
TABLE 5
Example 14 15 16 17
Olefin Reactant 2,3-DMBl 2,3-DMBl 2,3-DMB2 2,3-DBM2
volume (ml) 3.0 5.0 3.0 5.0
Catalyst 10Z Na/A1203 3% K/A1203 10% Na/A1203 3% K/A1203
weight (g) 1.5 1.4 1.5 3.4
Duration (mins) 10 15 10 50
Product (2,3DMBl 21% 11.2% 3.6Z 5.8Z
(2,3DMBl 79% 88.8% 96.4% 94.2%
Example 18
Pure 2,3-DMB-2 was passed over a fixed 2 ml catalyst bed of 25Z
sodium on alumina at a liquid hourly space velocity of one for six
hours each at 0C, 20C and 45C. Analysis of the products showed
they contained 4.8%, 6.4% and 8.1%, 2,3-DMB-l respectively.
This Example shows that 2,3-DMB-2 conversion increases with
16
1~79660
17
reaction temperature.
Example 19
1.5 kg of 2,3-DMB-2 and 0.15 kg of 10% sodium on alumina
(prepared as Example A) were placed in the kettle of a 40 plate
1 inch Oldershaw distillation column. 2,3-DMB-l of high purity
(99.9%) was obtained at a reflux ratio of 20:1 at a rate of
25 g/hour. The head temperature was 57C and the kettle temperature
was 73C.
Example 20
A 10 litre 3 neck distillation kettle was fitted with a
47 plate 2 inch Oldershaw column and a liquid outlet line to a pump
which circulated the distillation kettle contents over a heated
catalyst bed before returning the contents to the kettle through an
inlet line.
The kettle was charged with 2,3-DMB-2 (5.937 kg) and the
catalyst bed with Bayer Catalyst K2631 activated as in Example C.
The pump was then used to circulate the kettle contents over the
catalyst bed at 50C at a rate of 1.2 litres hour~l. The
concentration of 2,3-DMB-1 in the kettle gradually increased to
about 5.5Z after 36 hours, at which point the flask temperature was
raised and the distillation column brought to total reflux. After 5
hours the heads take-off was commenced at a reflux ratio of 60:1.
2,3-DMB-1 was taken off at a rate of 15 to 30 ml hour~l at a purity
of greater than 99% (by~gas-liquid chromatographic analysis).
17
