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Carbonylation of Olefins under Mild Temperature Conditions in the Presence of Palladium Complexes.

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Carbonylation of Olefins under Mild Temperature Conditions
in the Presence of Palladium Complexes
BY K. BITTLER, N. v. KUTEPOW, D. NEUBAUER, AND H. REISr*1
Dedicated to Proj.&ssorA . Steinhofer on the occasion of his 60th birthday
During a search for catalysts that allow carbonylation reactions on olefitis to proceed
below 100 'C, complex palladium(tt) compounds having the formula L,PdX,, were
found to be catalytically active. L denotes a ligand such as a phosphine, nitrile, amine,
or ole& X fs an acid residue, and m+n is 3 or 4. The catalysts permit the carbonylation
of heat-sensitive compounds, as well as selective carbonylation of polyunsaturated olefins.
The new process can also be carried out on the industrial scale, as is shown by the carbonylation of cyclododecatriene.
1. Introduction
In the carbonylation method developed by Reppe,
carbon monoxide is allowed to react with organic
compounds such as acetylenes, olefins, alcohols,
ethers, and esters under the catalytic influence of metal
carbonyls and carbonylmetal hydrides 111. The carbonylation of unsaturated compounds usually involves
the participation of compounds having an acidic
hydrogen such as water, alcohols, thiols, ammonia,
amines, or carboxylic acids. The end products are
carboxylic acids and their functional derivatives, unsaturated products being obtained from acetylenes
and saturated products from olefins [I].
The reaction of olefins with carbon monoxide and
water or alcohols to form acids o r esters was already
known when Reppe and his co-workers turned their
attention to this field. The earlier processes proceeded
only at high pressures (700-900 atm) and high temperatures (about 300 "C), in the presence of Latalysts
such as phosphoric acids, heteropolyacids, boron trifluoride, and metal halides. The metal carbonyls were
often regarded as reaction inhibitors, and even as
poisons for the catalysts, so that a great deal of work
was devoted to the suppression of their formation in
catalytic reactions such as the methanol synthesis.
However, Reppe's experiments with acetylene and
carbon monoxide under pressure showed that metal
carbonyls and carbonylmetal hydrides are excellent
carbonylation catalysts, which are effective at lower
temperatures. These catalysts make possible many
important and interesting syntheses.
In contrast to the earlier processes for olefin carbonylation, this reaction proceeds under relatively mild
conditions (about 30atm and 17OOC). Esters of
acrylic acid are obtained under the same conditions
from acetylene, CO, and alcohols in the presence of
halides of metals that form carbonyls, for example,
NiBr2 and NiI2, as well as complex Ni halides.
The next obvious step was to apply the experience
gained in the carbonylation of acetylene to that of
olefins. The attempt to prepare propionic acid and its
esters by the catalytic reaction of ethylene with CO
and water or alcohols in the presence of Ni salts or
Ni(C0)4 was an immediate success. Corresponding to
the lower reactivity of the double bond as compared
with the triple bond, however, much more vigorous
reaction conditions, e.g. 250-320 "C and 200-300atm,
must be used for the carbonylation of olefins.
Operation in this temperature range has certain disadvantages. Thus the carbonylation of olefins, particularly above
about 150 "C, is always accompanied by side reactions, such
as the water-gas reaction. The hydrogen that is formed hydroC O + H 2 0 = COz+ Hz
genates unreacted olefin, and reacts with CO and the olefin
t o form aldehydes, alcohols, and ketones, as well as other
products. Another disadvantage is that isomerizations, polymerizations, resinifications, and cleavages proceed more
readily at higher temperatures. There is also a danger of increased corrosion.
[*I Dr. K. Bittler, Dr. N.
Some (mainly straight-chain) olefins can be carbonylated to form carboxylic acids at 120-190 "C if water is
present in excess and if the reaction is carried out in
solvents such as ketones, dioxane, amides, or alcohols
with octacarbonyldicobalt as the catalyst [*I. In these
cases the solvents must dissolve both the olefins and
the carboxylic acids formed.
Olefins can be carbonylated at even lower temperatures
to give esters in a process developed by du PontE31.
[l] W. Reppe, Liebigs Ann. Chem. 582, 1 (1953).
[2] R. Ercoli, DAS 1092015 (1956), Montecatini.
[3] E. L. Jenner and R . V. Lindsey, j r . , US-Pat. 2876254 (1959),
Du Pont.
Reppe's first catalytic carbonylation was the reaction
of acetylene with CO and H2O under pressure to form
acrylic acid; nickel carbonyl was used as the catalyst.
v. Kutepow, Dr. D. Neubauer, and
Dr. H. Reis
Badische Anilin- & Soda-Fabrik AG, Hauptlaboratorium
67 Ludwigshafen am Rhein (Germany)
Angew. Chem. internat. Edit.
Vol. 7 (1968) 1 No. 5
329
The process is based on the reaction of the olefin with
CO and a primary monofunctional alcohol in the
presence of a catalyst system (an alcohol-soluble Sn or
G e salt and an alcohol-soluble salt of a rare metal of
group VIII in a molar ratio of 1:l to 20:l) at 100 to
3000 atm and 50-325 "C. Below 250 "C the reaction is
successful only with platinum salts. The reaction temperature required for the cheaper palladium salts is
above 250 "C and these compounds therefore offer n o
advantage over conventional catalysts.
This situation led to a search for new catalysts that
would act at lower temperatures than the conventional
catalysts, and would at the same time be relatively
cheap and accessible. We chose the Pd compounds,
which readily form complexes with olefins, since we
believed that the olefin could be carbonylated at a
lower temperature when activated via a Pd-olefin
complex than when the carbon monoxide is activated
via a metal carbonyl catalyst, as in the usual process.
The investigations soon led to Pd complexes such as
bis(tripheny1phosphine)palladium dichloride that satisfied our requirements and permitted p.g. the synthesis of esters of carboxylic acids below 100 "C[41.
Tsuji et al. [*-81 discovered independently that the reaction of
olefins with CO in an alcoholic solution of hydrogen chloride
in the presence of PdClz under conditions such as 80 O C and
100 atm leads to esters of saturated or unsaturated acids.
However, this process is accompanied by side reactions, such
as the addition of hydrogen chloride to the olefin. Moreover,
PdC12 in aqueous or alcoholic solution is readily reduced to
the metal by carbon monoxide.
2. Palladium Complexes and their Catalytic
Activity
Palladium metal, palladium carbonyl halides [9,IOI,
olefinpalladium halides [111, and complex palladium(0)
compounds have been considered for use as catalysts
for the carbonylation of olefins below 100 "C.
By analogy with the pure metal carbonyls used in
Reppe syntheses, palladium(0) compounds were examined first. Since palladium does not form metal
carbonyls, the complexes (I) and (2) were chosen.
[(C6Hs)3P14Pd
(1)
[(o-CH~-C~H~O)~P]~P~
(2)
[4] N. v. Kutepow, K. Bittler, and D. Neubauer, German Pat.
1221224 (1963), BASF; German Pat. 1227023, German Pat.
1229089, both patents are supplements to German Pat. 1221224,
BASF.
[5] J. Tsuji, M . Morikawa, and J . Kiji, Tetrahedron Letters, 1963,
1437.
161 J. Tsuji, J. Kiji, and M . Morikawa, Tetrahedron Letters 1963,
1811.
171 J. Tsuji, J. Kiji, S. Imamura, and M . Morikawa, J. Amer.
chem. SOC.86,4350 (1964).
[8] J. Tsuji. S. Imamura, and J. Kiji, J. Amer. chem. SOC.86,4491
(1964).
191 W. Manchot and J. Konig, Ber. dtsch. chem. Ges. 59/11, 883
(1926).
[lo] E. 0. Fischer and A . Vogler, J. organometallic Chem. 3, 161
(1965).
1111 M. S. Kharasch, R. C. Seyler, and F. R. Mayo, J. Amer.
chem. SOC. 60, 882 (1938).
330
Complex ( I ) is the more readily obtainable of' these.
It can be prepared, for example, by reactions (a) 1121 and
(b) 1141
A method (c) using cyclohexadiene[13,13al has also
proved useful:
Synthesis (c) can be simplified by the use of ally1 alcohol instead of cyclohexadiene, via the intermediates
x-allylpalladium chloride [I51 and x-allyl-n-cyclopentadienylpalladium [16). This modified route is also the
most suitable for the preparation of (2).
The carbonylation of ethylene and propylene with
alcohol as a reactant and 0.05-0.5% of tetrakis(tripheny1phosphine)palladium as the catalyst does not
proceed below 100 "C. On addition of catalytic quantities of hydrogen chloride to the reaction mixture,
however, the desired esters are formed, even at temperatures between 40 and 80 "C.
After the reaction, a yellow crystalline precipitate containing Pd was always observed; this was identified as
the known compound [(C6H5)3P]2PdC121171, which is
readily obtainable and very stable. This complex is so
active in the pure state that it can catalyze the carbonylation of olefins below 100 "C with or without the
addition of HCI.
Since Pd(0) compounds are evidently inactive in the
absence of HCI, whereas complex Pd(rr) halides exhibit high activity, a number of Pd(n) complexes were
prepared (some for the first time), and their activities
as carbonylation catalysts at low temperatures were
tested with many olefins. A selection of these Pd complexes is given in Table 1.
Bis(tripheny1phosphine)palladium dichloride and palladium complexes [41 containing triphenylphosphine
together with a more weakly bound ligand, such as
triphenylphosphinepiperidinepalladium dichloride or
triphenylphosphinebenzylarninepalladium dichloride,
have the highest catalytic activities, whereas olefin1121 L. Malatesta and M. Angoletta, J. chem. SOC. (London)
1957, 1186; cf. also 1955, 3924.
[13] E. 0. Fischerand H. Werner, Chem. Ber. 95,695,703 (1962).
[13a] S. D. Robinson and B. L. Shaw, J. chem. SOC. (London)
1964, 5002.
1141 K. Bittler, N. v. Kutepow, D. Neubauer, and H. Reis, unpublished.
[15] J. Smidt and W. Hafner, Angew. Chem. 71, 284 (1959).
[16] B. L. Shaw, Proc. chem. Soc. (London) 1960, 247.
[I71 J . Chatt and F. G. Mann, 3. &em. SOC.(London) 1939,1631.
Angew. Chem. internot. Edit. 1 Vol. 7 (1968) 1 No. 5
Table I .
Relative activities of palladium catalysts in carbonylations.
Apart from the complex ligands, the anion also plays
an important part. Only chlorides and bromides exhibit pronounced activity; palladium complexes that
contain a nitrate, iodide, acetate, or sulfate anion are
only moderately active catalysts.
3. Carbonylation of Olefins in the Presence of
Palladium Complexes
A wide range of esters can be prepared from olefins and
alcohols by carbonylation at low temperatures in the
presence of the palladium complexes listed in Table 2 [41.
palladium chloride complexes and even PdCl2 [51 itself
are less active as catalysts. This can be explained by
insufficient stabilization of bivalent palladium by ole-
These palladium catalysts can be used for the preparation not only of esters, but also of acids, by the use of
water instead of alcohols 141. However, temperatures
about 50 "C higher are generally required for the preparation of acids, so that greater demands are made
on the stability of the palladium catalyst toward reduction.
Table 2. Synthesis of esters by carbonylation of olefins in the presence of alcohols. Catalyst: ex.
[(C~HS)]P]~P~C!Z,
reaction conditions 300-700 atm CO.
Yield based
on reacted
olefin (%)
Olefin
~~~~
CHz=CHz
CH,-CH=CH-CH,
CH,-CH=CHz
60- 100
Diisobutylene
120
CH-COOCzHs
140
70
SO-70
100
70
90
90
60
4-Vinylcyclohexene ( 5 )
120
1,5-Cyclooctadiene
1,S-Cyclooctadiene
1,5,9-Cyclododecatriene (8)
60
100
35-50 [a]
1,5,9-Cyclododecatriene (8)
50-70 [a]
1,5,9-CycIododecatriene (8)
Cyclooctatetraene
+
90
95
90
92
70
I
I<
CH-COOCzHs
CHI= CH-CH20H
CHz=CH-CH=CH2
Styrene
Diethyl-4-cyclohexene1J-dicarboxylate (3)
4-Vinylcyclohexene ( 5 )
CH~-CHZ--COOC~H~
CH~-CH~-CH(CHJ)-COOCH,
CH3-CHz-CHz-COOC2H5
(CH~)ZCH-COOC~H~
(CH,)IC-CH~-C(CHI)~-COOC~HS
and isomers
HsC200C-CH-COOCzHs
> 70 [a]
90
CHz-COOCzH5
CH~=CH-CH~-COOCHI
CHI-CH=CH-CHZ-COOC~H~
C6Hs-CH(CHs)-COOCzHs
Triethyl 1.2,4-cyclohexanetricarboxylate ( 4)
Methyl 2-(3-cyclohexenyl)propionate (6)
Methyl Z-(methoxycarbonylcyclohexy1)propionate (7)
Ethyl 4-cyclooctene-1-carboxylate
Diethyl cyclooctanedicarboxylate
Ethyl 4,8-cyclododecadieneI-carboxylate (9)
Diethyl 5-cyclododecenedicarboxylate (10)
(9)
(I I )1
Triethyl cyclododecanetricarboxylate
(11) 1+19)
(l0)l
Ethyl bicycIo[4.2.0]octa-2,4-diene7-carboxylate
[+
+
+
65
71.5
95
88
85
80
95
80
> 90
70-80 (10)
70-80 (11)
33
[a] The temperature limits depend on the HCI concentration, the catalyst concentration, and in some
cases the catalyst used; the temperature limits indicated are valid for 0.35% of [(C&i~)]P]zPdC12 and
10% of HCI in C ~ H S O H .
fins as ligands in the presence of carbon monoxide, so
that it is reduced by CO to the metal, which is inactive
in this reaction unless hydrogen halide is added. The
activity of the olefinpalladium chlorides increases at
higher hydrogen chloride concentrations. The activity
is reduced by high temperatures and by high
monoxide pressures.
Angew. Chem. internat. Edit.
Vol. 7 (1968) 1 No. 5
The palladium(r1) complexes which are always added
only in catalytic quantities, also catalyze the formation
of acyl chlorides from olefins, CO, and hydrogen
chloride [181, and of anhydrides from olefins, CO, and
acid
[18] N. v. Kutepow, K . Bittler, D . Neubauer, and H . Reis, German
Pat. 1237116 (1964), BASF.
331
COOC 2HS
Whereas carbonylation of olefins with isolated double
bonds always results in the loss of the double bond,
allyl alcohol and allyl chloride are carbonylated with
retention of the double bond 14,191.
CHZ= CH-CH2X
+ CO + ROH
/
i-
CHz = CH-CHzCOOR
X = halogen or OH
R = alkyl or aryl
+ HX
+ X
C O + x C2H50H
x - 1, 2, 3
(8)
+
6
(9)
H5C200C
(10)I+ (9/1
\
\r
rfCOoCzH5
4. Advantages of the Complex Palladium Catalysts
The greatest advantage of the complex palladium
catalysts, which catalyze the carbonylation even at
concentrations of 0.05% and less, is their activity at
low temperatures. Carbonylation with conventional
catalysts, such as metal carbonyls of the iron group,
takes place only at temperatures above 160°C, i.e.
temperatures at which the heat-sensitive olefins decompose, polymerize, isomerize, or in the presence of
water and carbon monoxide, are hydrogenated by the
hydrogen formed.
Vinylcyclohexene ( 5 ) can also be converted either into
the cyclohexenylpropionate (6) or into the diester (7)
by variation of the conditions.
Thus Diels-Alder adducts such as the cyclohexene
derivative ( 3 ) and the corresponding norbornene
derivative, which readily dissociate into their components at high temperatures, were carbonylated for
the first time with palladium complexes.
COOCzH,
0 ecooc
+
ZH5
-@
c00c2H5
ooC2H5
+CO
+ CZHJOH
H5C zOOC+C
S O T , 700 atm
Another surprising advantage of the palladium complexes is that polyunsaturated olefins can be selectively
carbonylated in their presence. For example, it was not
previously possible to convert 1,5,9-cyclododecatriene
(8) into 4,8-cyclododecadiene-l -carboxylic acid or its
esters or to corresponding polycarbonylated compounds, since acenaphthene derivatives and polymerization products were formed instead. Although
Riill [I91 recently obtained esters of cyclododecanecarboxylic acid by the reaction of (8) with CO and
alcohol in the presence of [Co(CO)& as catalyst, this
process leads to many by-products. The complex
palladium(I1) catalysts, on the other hand, made it
possible to cause one, two, or all three double bonds
in cyclododecatriene to react, depending on the reaction conditions, to give mainly the mono- ( 9 ) , di- ( l o ) ,
and triester (11); the monoester can in fact be obtained
without by-products.
When trans,trans,cis-l,5,9-~yclododecatriene
is used,
one of the two trans double bonds reacts first, and
then the cis double bond.
1191 Th. RiiII, Bull. SOC.chim. France 10,2680 (1964).
332
(71
OOC 2H5
WC0OCZH5
5. Mechanism of the Reaction
The catalyst could promote carbonylation by activation either of the carbon monoxide o r of the olefin by
addition to the central atom of the complex.
Activation of CO below 150°C may be ruled out,
since non-olefinic compounds, such as alcohols and
alkyl halides, that can be satisfactorily carbonylated
with conventional catalysts cannot be carbonylated
with palladium(I1) complexes.
Thus the catalyst must activate the double bond of the
olefin. A feasible explanation for this process is that
the olefin displaces a ligand from the palladium complex, and is itself bonded to the palladium by a x bond.
This intermediate has not yet been isolated, but the
above assumption is supported by the fact that complexes in which two ligands are bound unequally
strongly to the central atom are particularly active.
The carbonium ion of the polarization-activated
Angew. Chem. internat. Edit. / Vol. 7 (1968) 1 No. 5
Table 3. Isomer distribution in the reaction products from olefins R*RZC=CH,, alcohols ROH, and CO. Catalyst:
[ ( C ~ H ~ ) ~ P ] ~ Preaction
~ C I Z ,conditions: 90-120 " C ; 700 atm CO; 3-4% HCI i n ROH.
]
Olefin
H
H
H
CH, --CH CHI
CH2 CHCl
CHI CH-CHrCOOR
CH,
CI
CHzCOOR
i
Principal product
60% (CH3)zCHCOOR
80% CH,--CHCI--COOR
80% CHz-- COOR
1 By-product
1
I R
1
30% CHI-(CHZ)~--COOR
5 % CI-(CH~)Z-COOR
10% ROOC--(CH~)J-COOR
C2H5
C~HS
CH,
I
CH,
H,C-CH-COOR
60 % (CHj),C-COOR
CHi
30 % (CHJ)~CH-CHZ--COOR
CzHs
Table 4. Influence of the reaction conditions on the distribution of products in the carbonylation of 1,5,9-cyclododecatriene (CD1) in the presence of
ethanol. Pressure: 300 atrn CO (parts a , c, and d ) or 700 atrn CO (part b).
I
I
Catalyst
1
Concn.
based on
feed
(wt.-%)
CZH~OH
HClin
:CDT
C2HsOH
(molar
ratio)
0.35
0.35
0.35
0.35
0.35
E
0.35
0.35
0.35
0.35
0.35
0.35
2:l
zx 2:l
=
=
=
s5
x
=
s5
s5
=
2:l
2:l
2.1
2:l
2:l
2: 1
2:l
2:l
2:l
1 I
Temp.
50
50
50
50
50
10
50
60
70
80
90
100
10
10
~
1 ;Fr 1 1
~~~
After vacuum distillation (parts)
Crude
, ~ discharge
~ ,
10
10
10
10
10
10
10
10
~~~~~~
I
CDT
mono-
diester
triester
(10)
Yxsidue
-
278
270
276
268
299
[a]
[a]
[a]
[a]
[a]
88
95
64.5
26
13
99
55
76.5
133
120
38
86.5
281
288
302
306
308
298.5
[a]
[a]
[a]
[a]
[a]
[a]
78
35
5
84
I18
94
63
53.5
44
50.5
121
117
135
127
<5
4
2.4
-
-
6.5
4
11
12
15
8
16
25
27
51
49
[a] The crude discharge is washed twice with a solution of CaCI2, washed once with a solution of NazCO3, and dried over solid CaCI2 before vacuum
[cl Alcohol distilled off at atmospheric pressure.
distillation.
[b] CsHltN = piperidine.
double bond then undergoes nucleophilic attack by
68
carbon monoxide in its resonance form :C
I
-5
-C
-&:G
f)
-+ +
3 0:
-&a
b0 60
:CEO:
66
--D
I
Q
-7-c*
0:
In the absence of hydrogen chloride, the intermediate
then reacts with alcohol, and the reaction product is
simultaneously released from the catalyst.
ligands, and these ligands can therefore be removed
more readily.
In the carbonylation of olefins of the type RIR2C=CH2,
where R1 and R2 are first order substituents, carbon
monoxide preferentially attacks the carbon atom
carrying the smaller number of hydrogen atoms
(Table 3). This behavior is reminiscent of the rules for
the addition of hydrogen halides (Markovnikov rule).
6. Selective Carbonylation of
1,5,9-CycIododecatriene
Small quantities of hydrochloric acid very greatly
increase the reaction rate. This effect is probably due
to the higher acidity of the hydrogen in HCl as compared with alcohols; the synthesis of the esters probably proceeds via an intermediate acyl chloride.
Acyl chlorides are in fact obtained in the absence of
alcohol o r water [6,181. Moreover, hydrogen chloride
may catalyze the addition of the olefin to the catalyst,
since it forms quaternary salts with basic complex
Angew. Chem. internat. Edit.
1 Vol. 7 (1968) J No. 5
The carbonylation of the heat-sensitive 1,5,9-cyclododecatrieneC4J was studied closely, since this is an ideal example of
a selective carbonylation; moreover, there has been considerable interest for a long time in the preparation of 13tridecanolactam [201 by conversion of 1,5,9-~yclododecatriene via 4,8-cyclododecadiene-l-carboxylateinto cyclododecanecarboxylate, followed by reaction of the latter ester
with nitrosylsulfuric acid.
Bis(tripheny1phosphine)palIadium dichloride was found to
be the best catalyst because of its selective action, resistance
to reduction, relative activity, and ready availability (see
Table 4, Part a).
Table 4, Part b, illustrates the temperature-dependence of the
reaction. Higher temperatures favor the formation of the
[20] H . Metzger and H . Urbach, German Pat. 1192649 (1961),
BASF.
333
diester, and ultimately of the triester. At sufficiently low
temperatures (about 50 “ C ) ,only the monoester ( 9 ) is formed.
A very close relationship exists between the catalyst concentration and the temperature. It can be seen from Table 4,
Part c, that if the catalyst concentration is decreased, the
temperature must be raised in order to obtain roughly the
same conversions and yields under otherwise identical conditions.
Cyclododecatriene can in principle be carbonylated even in
the absence of hydrogen halide. However, higher reaction
temperatures are required in neutral than in acidic media
under otherwise identical conditions. The strong influence of
hydrogen chloride on the reaction rate can be seen from the
fact that no diester is formed in the absence of hydrogen
chloride. despite the higher temperature (see Table 4, Part d).
Cyclododecatriene and alcohol can be made to react in
stoichiometric quantities. If necessary, alcohol can be used in
excess. Carbon monoxide is sufficiently soluble in the reaction
mixture a t 300 atm to permit the reaction to be carried out in
an industrially favorable pressure range.
The influence of the contact time and in particular its effect
on the influence of the other parameters was studied in the
apparatus shown in Figure 1 (see also Table 5).
Table 5 shows, inter alia, that diester formation can be suppressed by the use of a shorter contact time, since diethyl
cyclododecenedicarboxylate is not formed directly from
cyclododecatriene, but from the monoester.
7. Re-use of the Catalyst
The recovery and re-use of the catalyst is of the utmost importance in the industrial use of the synthesis. It was found
preferable not to isolate the complex as such, but to return it
to the synthesis in the form of the “catalyst residue” obtained
when the alcohol, the cyclododecatriene, and the monoester
are distilled off.
The first experiments were carried out in autoclaves with glass
inserts to exclude any effects due to foreign ions from the
wall of the autoclave. I t is shown in Table 4, Part d, that
higher temperatures are necessary in order to obtain the same
conversion and yield in the absence of hydrogen chloride.
However, to allow the catalyst tests with and without hydrogen chloride to be carried out a t approximately the same
temperatures, the catalyst concentration was increased by a
factor of about ten for the experiments without HCI to ensure
that the same conversions and yields would be obtained.
When the catalyst is re-used, hydrogen halide must be added,
since the catalyst is otherwise inactive, even at higher concentrations, after having been used once.
Figure 2 shows the behavior of the catalyst in the presence of
and in the absence of HCI.
Fig. 1. Apparatus for the carbonylation of trans,trans,cis-1,5,9-cyclododecatriene (CDT). 10 1 Hofer autoclave fitted with a magnetic lifter
agitator and lined with Hastelloy B; continuous operation.
1 = stirrer, 2 = magnet, 3 = immersion tube, 4 = discharge vessel,
5 = waste gas outlet.
Alcoholic hydrochloric acid and bis(tripheny1phosphine)palladium dichloride in cyclododecatriene are pumped into
the 10-1autoclave. Liquid and gas arecontinuously withdrawn
into a pressureless glass vessel through an immersion tube
fitted in such a way that 4 I of liquid are always present in the
autoclave. The distance between the sieve plates on the
magnetic lifter agitator and the frequency and stroke are
determined beforehand in model experiments for optimum
mixing of the gas and liquid phases.
0
1
n-
2
3
4
0
1
2
3
L
n-
Fig. 2. Attempts to re-use the catalyst. Experiments with HC1 (left):
75 “C, 300 atm CO, % 0.055 wt.- % of I(C6Hs)sPl~PdC12,molar ratio
ethano1:cyclododecatriene = 1 . 2 1 . 3.3 wt.-% of HCI in C2HsOH.
Experiments without HCl (right): 80 OC, 300 atm CO, 0.45 wt.- % of
[(C6H&P]zPdC12, molar ratio ethano1:cyclododecatriene 1.2: 1.
Abscissa: n = frequency of re-use.
In the presence of HCl. the catalyst is sufficiently active even
after being re-used three times. The decrease in activity after
repeated use is due mainly to mechanical losses during the
Table 5. Relationships between contact time, temperature, catalyst concentration, alcohol concentration, monoester and diester formation, and space-time yield in the carbonylation of trans,
trans,cis-l,5,9-~yclododecatriene
(CDT). Catalyst: [(CsH&P12PdC12; CO pressure: 300 atm.
__
Temp.
( “C)
75
105
105
105
105
115
Catalyst
concn. based
on feed
(wt.- %)
0.06
0.06
0.04
0.04
0.05
0.05
Contact
time
(h)
1.7
0.8
1.33
1.33
1.66
0.85
1.85
1.0
2.4
1.5
1.5
1.2
I .6
1.4
1.0
1.0
1.4
1.4
1.0
1.0
1.4
1.4
0.8
1.33
1.33
1.66
115
120
0.04
0.04
1.85
1.85
120
120
0.03
0.02
1.85
1.85
Space-time
yield
kg.1-Id-1
Monoester
( %)
Diester
( %)
in discharge
-
1.8
3.9
3.7
4.8
3.8
4.7
(max. 5.4)
4.2
5.3
(max. 5.9)
4.0
2.4
26
33
30.5
30.4
31
43.5
0
13.5
10.5
5.5
29.5
38.5
2.5
6
30
17
2
0
L
6.5
[a] Acid value of the alcohol = 2 5 .
334
Angew. Chem. internat. Edit. 1 Vol. 7 (1968) 1 No. 5
co
preparation of the catalyst residue. Slight losses also occur,
particularly a t higher temperatures, as a result of the reduction of palladium(1r) to metallic palladium; this reduction
becomes even more pronounced when the “more waterlike” methanol is used instead of ethanol.
It is advantageous to add one mole of triphenylphosphine per
g-atom of palladium 1211 to the catalyst residue.
8. Industrial Synthesis of
Cyclododecadienecarboxylate
1
@
On the basis of the above results, a pilot plant (synthesis and
isolation sections) was constructed for the continuous production of the monoester. Hastelloy alloys, particularly
Hastelloy B, must be used for parts subjected to high pressures. Low-pressure parts were made of glass. A scheme of
the pilot plant is shown in Figure 3.
Alcohol containing HCl was fed, together with dissolved
catalyst residue, cyclododecatriene with fresh catalyst, and
technical carbon monoxide (300 atm), into a 3-1 reactor lined
with Hastelloy B. Unreacted carbon monoxide is re-introduced into the reactor; inert gases are displaced from the reactor
as waste gas. The product discharged from the reactor is
freed from alcohol in the first thin-film evaporator. The alcohol is condensed and returned to the reaction after the addition of hydrogen chloride. The residue containing the catalyst
is separated from unreacted cyclododecatriene and monoester in the second thin-film evaporator. Most of the catalyst
co
-
t
catalyst
cataivst
C,H,O’HIHC~
residue
1663221 catalyst residue
Fig. 3 . Experimental plant for the industrial synthesis of cyclododecadienecarboxylate. 1 =- circulating gas pump, 2 = reactor, 3 = first thinfilm evaporator, 4 = second thin-film evaporator, 5 = column.
CDT = cyclododecatriene, ME = monoester.
residue is also returned to the synthesis. The mixture of monoester and cyclododecatriene vapors from the second thin-film
evaporator is passed into a separating column, unreacted
cyclododecatriene being obtained as the head product. The
pure ethyl cyclododecadienecarboxylate is obtained as a
residue at the bottom of the column in a yield of 90%. based
o n reacted cyclododecatriene.
Received: January 11, 1968
[A 632 IEI
German version: Angew. Chem. 80, 352 (1968)
Translated by Express Translation Service, London
[21] N . v. Kutepow, K . Bittler, D . Neubauer, and H. Reis, German
Pat. Appl. B 79819 IVb/120 (BASF).
Sulfonyl Hydrazones of Cyclic Amides and Quaternary Azo Sulfones of
Heterocycles as Reagents in Azo Chemistry
BY S. H m I G [*I
IN COLLABORATION WITH W. BRENNINGER, H. GEIGER, G. KAUPP, W. KNIESE,
W. LAMPE, H. QUAST, R. D. RAUSCHENBACH, AND A. SCHUTZ
Dedicated to Professor A . Steinhofer on the occasion of his 60th birthday
Sulfonyl hydrazones of cyclic amides undergo oxidative coupling with phenols and
reactive methylene components. The reaction proceeds via the azo surfones, which may
be used as such, and which, as ambident cations, enter into many reactions with nucleophiles and extend the scope of Oxidative coupling. The reaction with phenols is a two-step
process, in which the limiting cases kl
k2, kl = kz, and kl
k2 can be realized by
slight variation of the reactants.
<
1. Introduction
Some years ago, two articles[21 were published concerning a new principle for the introduction of
the azo group into aromatic amines, phenols, and
reactive methylene compounds. These nucleophilic re-
____
[*] Prof. Dr. S. Hiinig
Institut fur Organische Chemie der Universitat
87 Wiirzburg, Rontgenring 11 (Germany)
[l] Part XXIX of the series “Azo dyes by oxidative coupling”.
- For Part XXVIII, see [26].
Angew. Chem. internat. Edit.
Vol. 7 (1968)
No. 5
>
actants exhibit general coupling with amidrazone
systems (I) or their vinylogs ( 2 ) under the action of
Oxidizing
agents.
examples Of
comb
I
;S-C=N-NH~
I l
;N-c=c
l
-c=N - N H ~
(1)
(2)
____
[2] a) S. Hiinig, H . Balli, K. H. Fritsch, H. Herrrnann, G . Kobrich, H. Werner, E. Grigat, F. Miiller, H. Nother, and K.-H. Oette,
Angew. Chem. 70, 215 (1958); b) S.Hunig, H. Balli, E. Breither,
F. Bruhne, H. Geiger. E. Grinat, F. Miiller. and H . Ouast. Ansew.
Chem. 74,818 (1962); Angew. Chem. internat. EdiT2,640 (1962).
335
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