Liquid phase oxidation of alkenes with nitrous oxide to carbonyl compounds

Article abstract of DOI:10.1002/adsc.200303155

A variety of substrates including linear, cyclic, heterocyclic alkenes and their derivatives were tested in the liquid phase non-catalytic oxidation with nitrous oxide (N₂O). The structure and composition of the alkenes have a significant effect on the reaction selectivity. With many alkenes, N ₂O oxidation provides a selective way for the preparation of carbonyl compounds. The generation of carbene (or diazomethane) species is a remarkable feature of the oxidation of terminal alkenes.

Full text of DOI:10.1002/adsc.200303155

FULL PAPERS
Liquid Phase Oxidation of Alkenes with Nitrous Oxide to
Carbonyl Compounds
E. V. Starokon, K. A. Dubkov, D. E. Babushkin, V. N. Parmon, G. I. Panov*
Boreskov Institute of Catalysis, Novosibirsk 630090, Russia
E-mail: Panov@catalysis.nsk.su
Received: October 1, 2003; Revised: November 11, 2003; Accepted: January12, 2004
Abstract: A varietyof substrates including linear,
compounds. The generation of carbene (or diazo-
cyclic, heterocyclic alkenes and their derivatives were methane) species is a remarkable feature of the
tested in the liquid phase non-catalytic oxidation with oxidation of terminal alkenes.
nitrous oxide (N2O). The structure and composition
of the alkenes have a significant effect on the reaction Keywords: alkenes oxidation; carbene; carbonyl com-
selectivity. With many alkenes, N O oxidation pro- pounds; cycloheptatriene; cyclopropane; methylene;
2
vides a selective wayfor the preparation of carbonyl
nitrous oxide
Introduction
semi-quantitative nature of their study(efficient ana-
lytical techniques such as GC, GC-MS, NMR were not
In the past decade, nitrous oxide has attracted a great available that time), could correctlydescribe the main
deal of attention from researchers as a selective oxygen reactivitypatterns of various alkenes. Theyalso sug-
donor for conducting the catalytic oxidation of hydro- gested a 1,3-dipolar N2O cycloaddition mechanism
carbons. It is being used especiallywidelyin the gas
involving the intermediate formation of 1,2,3-oxadiazo-
phase oxidation of aromatic compounds. The most line, decomposition of which leads to the carbonyl
successful reaction of this type is direct oxidation of compounds. The following equation for the case of
benzene to phenol over Fe-containing zeolites:
cyclohexene oxidation is an example:
ꢀ1†
ꢀ2†
This mechanism well explains the experimental data[8 11]
Based on this reaction, a new phenol process has been
developed and successfullytested with a pilot plant
providing 97 98% yields of phenol.[1] The results of and was supported byrecent quantum-chemical calcu-
manystudies in this field were discussed in a number of
lations.[12,13] But the authors[9,10] presented no numbers
for selectivity, conversion, or yield. The selectivities in
reviews.[2 7]
Besides great opportunities, the gas phase oxidation refs.[9,10], when the reported data allow one to make an
also has some difficulties. Product desorption from the estimation, were quite low. Thus, in the case of cyclo-
catalyst surface is a main problem. It needs elevated hexene oxidation, which is one of the most selective
temperatures, which frequentlylead to degradation of
products and deactivation of the catalyst.
examples, the selectivityto ccylohexanone did not
exceed 64%. Low selectivities are possiblyrelated to
In order to solve these problems, we tried to transfer the harsh conditions of the experiments, which typically
the oxidation into the liquid phase, assuming that this were conducted at 3008C and 500 atm. To provide such a
should facilitate product removal from the surface, thus high pressure and to decrease the danger of an explosion
increasing the number of possible catalytic reactions. when compressing N2O, the authors [9,10] used a specially
This idea has come true onlypartl,y but instead it
brought us to the unexpected discoveryof a non-
designed mercurycompressor. One maythink that low
selectivities coupled with harsh reaction conditions,
catalytic oxidation of alkenes with nitrous oxide to which are difficult to provide in laboratorypractice, are
carbonyl compounds.[8]
a reason whysince 1951 no attempt has been made to
reproduce or to improve results of Bridson-Jones
et al.[9,10]
The main distinctive features of our work are the
milder and easilyavailable experimental conditions, and
Later, we learned that actuallythis reaction type had
been discovered and extensivelystudied alreadyin 1951
byBridson-Jones et al. [9,10] This group of ICI researchers
tested a broad varietyof substrates and, in spite of the
268
¹ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
DOI: 10.1002/adsc.200303155
Adv. Synth. Catal. 2004, 346, 268 274

Liquid Phase Oxidation of Alkenes with Nitrous Oxide
the higher selectivity. Oxidations of cyclohexene to
FULL PAPERS
From Equation (3) one can see that the ratio between
cyclohexanone[8] and cyclopentene to cyclopentatone[11] reaction routes 1 and 2 maybe expressed via the
were shown to proceed in the temperature range 150
2508C under 30 100 atm with 96 99% selectivity. The
latter remains nearlyunchanged at increasing conver-
sion up to over 90%.[11] The simplicityand high
selectivityof these reactions stimulated our efforts to
concentrations of corresponding products:
ꢀ4†
extend this approach to other substrates. The present In the case of ethylene, due to the symmetrical location
work is devoted to a screening of alkenes including of double bond in the molecule, onlyone configuration
several alkenes identical to those tested in refs.[9,10] The of the intermediate complex is possible. Decomposition
main purpose of the studyis to obtain a quantitative
of this complex leads to the formation of 91% acetalde-
basis for estimating the prospects and limitations of the hyde and minor products resulting from methylene
À
liquid phase N2O oxidation for preparing carbonyl reactions generated bycleavage of the C C bonds
compounds. The results are discussed further according (entry1). For the other alkenes, the ratio R 1/R2 maybe
to alkene types.
calculated with the experimental results presented in
Table 1. The calculation reveals a dominating role of
route 2. Thus, in the case of propylene (entry 2), the ratio
equals 1:2.3; in the case of 1-hexene (entry3), 1:3.7; and
in the case of 1-octene (entry4), 1:4.2.
Results and Discussion
For these alkenes one mayalso calculate a fraction of
the cleavage type decomposition of complex II:
Linear Alkenes
The oxidation of linear alkenes (Table 1) exhibits
particular features depending on the position of the
double bond in the molecule. For the case of terminal
ꢀ5†
alkenes (entries 1 4), a general scheme of the oxidation This fraction slightlyincreases from propylene (42%) to
maybe suggested as follows:
1-hexene (48%) and 1-octene (48%). The resulting
methylene generated by the cleavage may react with,
apart from a starting alkene, also the solvent benzene. It
mainlyincorporates into the aromatic nucleus yielding
cycloheptatriene, which is responsible for a significant
part of the reaction products (12 18%). Small amounts
of toluene (ca. 0.5%) are also produced.
The widening of the aromatic nucleus bythe methyl-
ene generated from diazomethane is known in the
literature.[14] But with the methylene generated by N2O
oxidation of an alkene, this reaction is probably
reported here for the first time.
ꢀ3†
Similar to ref.[9], with all terminal alkenes studied here,
no expected formaldehyde was detected.
The oxidation of unsubstituted non-terminal alkenes
is exemplified by2-pentene (entry5). The reaction
proceeds with a smaller cleavage, producing 2- and 3-
Equation (3) shows that the reaction mayproceed via pentanones comprising in sum 88% of the reaction
two routes leading to the formation of an aldehyde (A) products. A number of substituted non-terminal alkenes
or ketone (K). These routes are assumed to relate to were also studied including crotyl alcohol, crotononi-
different configurations of the intermediate 1,2,3-oxa- trile, mesityl oxide, 3-methyl-2-buten-1-ol, styrene, and
diazoline complexes, with the oxygen being attached to stilbene. Theyall contain a functional group located in
the first (complex I) or the second carbon atom (com- the vinyl or allyl position, and all exhibit low selectivity
plex II). Decomposition of complex II mayoccur in two
due to various side reactions (polymerization, dehydra-
À
ways, i.e., without cleavage and with cleavageof the C C tion, etc.).
bond. The latter route leads to an aldehyde with a
smaller number of carbon atoms (A') and the methylene
(or diazomethane) species, which is immediatelyinter-
cepted byanother alkene molecule yielding the corre-
sponding derivative of cyclopropane.
Carbocyclic Alkenes
Results for this type of alkene are presented in Table 2.
Due to the symmetrical location of the double bond in
Adv. Synth. Catal. 2004, 346, 268 274
asc.wiley-vch.de
¹ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
269

E. V. Starokon et al.
FULL PAPERS
unsubstituted rings (entries 1 4), their oxidation may Cycloalkadienes
provide a single ketone, which in all cases forms with
high selectivity(94 99%). One maynote a slight
tendencytowards an increasing contribution of side
These compounds contain two double bonds, which can
consecutivelyreact with N 2O, yielding accordingly
reactions in the cyclopentene to cyclododecene se- unsaturated monoketones and diketones. We studied
quence, which is mainlydue to opening of a ring 1,4-cyclohexadiene and 1,5-cyclooctadiene which have
leading to the formation of aldehydes. Minor products isolated double bonds, and 1,3-cyclohexadiene which
of aldol condensation are also detected in the reaction has conjugated bonds.
mixture.
The distribution between mono- and diketones is an
The presence of a substituent at a distant position interesting feature of the reaction. In the oxidation of
from the double bond provides for the formation of 1,4-cyclohexadiene (equation 6), 3- and 2-cyclohexen-1-
isomeric ketones, in most cases keeping the high total ones are the main products comprising 90 92%:
selectivity. For example, 4-methyl-1-cyclohexene (entry
5) and 4-(3-cyclohexen-1-yl)pyridine (entry 6), having
substituents in position 3, givethe twoexpected isomeric
cyclic ketones with total selectivities of 95% and 97%,
ꢀ6†
respectively. In the case of 6-methyl-3-cyclohexene-1-
methanol (entry7), the selectivityis lower, which seems
to be caused mainlybydehydration of the alcohol.
However, the oxidation of 1-methyl-1-cyclohexene
having a substituent in position 1 (entry8), proceeds
Note that with 1,4-cyclohexadiene, 20 25% of the
much less selectively, providing only 44% of a cyclic converted alkene was consumed for a polymerization
ketone (2-methyl-1-cyclohexanone) in the reaction process, which is not taken into account when calculat-
products. In this case, the reaction is accompanied bya
ing the product composition shown in Equation (6).
significant cleavage of double bonds leading to forma- With 1,5-cyclooctadiene, no polymerization was noted.
tion of 1-cyclopentyl-1-ethanone and 6-hepten-1-one. The concentration of diketones is verysmall and at
An aldehyde C7H12O (presumably5-heptenal) is also
found in the reaction products (2 3%).
conversion X ˆ 37% comprises only3% instead of the
expected statistical 9%. This low amount of diketones
mayindicate that the introduction of the first carbonyl
Table 1. Oxidation of linear alkenes (P0N O ˆ 10 atm, 2208C, 12 h).
2
EntrySubstrate
Conversion [%]
Product composition [mol %]
1
Ethylene,
0.08 mol in 50 mL benzene
27
acetaldehyde, 91
cyclopropane, 4
cycloheptatriene, 3
2
3
4
5
Propylene,
0.08 mol in 50 mL benzene
26
propanal, 23
acetone, 31
acetaldehyde, 22
methylcyclopropane, 4
cycloheptatriene, 15
1-Hexene,
0.08 mol in 50 mL benzene
35
30
22
hexanal, 15
2-hexanone, 29
pentanal, 27
butylcyclopropane, 14
cycloheptatriene, 12
1-Octene,
0.06 mol in 50 mL benzene
octanal, 13
2-octanone, 28
heptanal, 26
hexylcyclopropane, 9
cycloheptatriene, 18
2-Pentene,
0.14 mol in 50 mL benzene
2-pentanone, 41
3-pentanone, 47
acetaldehyde, 5
propanal, 3
cyclopropanes, 1
270
¹ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
Adv. Synth. Catal. 2004, 346, 268 274

Liquid Phase Oxidation of Alkenes with Nitrous Oxide
FULL PAPERS
Table 2. Oxidation of carbocyclic alkenes (25 mL, P0N O ˆ 25
plained bya more distant location of the double bonds in
the 1,5-cyclooctadiene molecule.
2
atm).
It is interesting that among the oxidation products of
1,5-cyclooctadiene, thorough NMR analysis identifies
reliably3
a-hydroxyhexahydro-1(2H)-pentalenone.
Most probably, this compound forms as a result of
intramolecular aldol condensation of 1,4-cyclooctane-
dione, the contribution of which increases with the
temperature and at 2208C consumes 50% of the latter
[Equation (7)].
The oxidation of conjugated 1,3-cyclohexadiene is
stronglycomplicated bythe Diels Alder side reaction.
Therefore, the main part of the diene is consumed bya
dimerization process, and only25 30% are involved in
the oxidation, yielding cyclic ketones.
Bicyclic Alkenes
Results for this type of alkene are presented in Table 3.
The oxidation of norbornylene (entry 1) leads to the
formation of both ketone (norcamphor) and aldehyde
(1-formyl-3-methylenecyclopentane) in approximately
equal amounts, indicating that a significant cleavage of
the double bond occurs. There is also a set of other
reaction products, which we have not yet identified with
certainty.
group into 1,4-cyclohexadiene deactivates the remain-
The oxidation of 1,2-dihydronaphthalene proceeds
ing double bond and makes it more resistant to with a minor cleavage and yields a- and b-tetralones
oxidation. An approximately10-fold predominance of
1,4- vs. 1,3-cyclohexanedione is observed.
with the total selectivityof 93% (entry2). Oxygen adds
predominantlyto the a-position, and the amount of a-
The formation of two cyclohexenone isomers in the tetralone is approximatelytwice that of b-tetralone.
oxidation of 1,4-cyclohexadiene is a noteworthy result, In the oxidation of indene, where the double bond is
since addition of one oxygen atom to any position of the located in a 5-membered ring (entry3), oxygen also
starting molecule should lead to the formation of only3- adds to both positions, but the preference for the a-
cyclohexen-1-one. Formation of 2-cyclohexen-1-one position becomes even greater. The ratio of a-indanone
maybe explained bymigration of the double bond to b-indanone is 4.5:1. Presumably, 2-ethenylbenzalde-
under the reaction conditions to the thermodynamically hyde also forms ( ꢁ 10%) as a result of the double bond
more favorable conjugated position. This process in- cleavage in the indene molecule.
tensifies with the increasing reaction temperature. Thus,
Table 3. Oxidation of bicyclic alkenes (P0N O ˆ 10 atm).
at 2008C, the ratio between the cyclohexenone isomers
2
is 1:0.2 [Equation (6)], while at 2508C it is 1:0.7.
Oxidation of 1,5-cyclooctadiene also leads to the
formation of mono- and diketones [Equation (7)]:
ꢀ7†
However, unlike 1,4-cyclohexadiene, this diene forms
onlyone monoketone isomer. Besides, there is no
ˆ
deactivation effect of the C O group, so that in this case
the diketone fraction is much greater, being close to the
statistical value. These distinctions are probablyex-
Adv. Synth. Catal. 2004, 346, 268 274
asc.wiley-vch.de
¹ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
271

E. V. Starokon et al.
FULL PAPERS
Table 4. Oxidation of heterocyclic alkenes.
Heterocyclic Alkenes
Among alkenes of this type we tested rings containing
oxygen, nitrogen and sulfur (Table 4). 5-Membered
heterocycles with similar molecular structures (2,5-
dihydrofuran, 3-pyrroline, butadiene sulfone) exhibit
different reaction patterns depending on the nature of
the heteroatom. The oxygen-containing ring of 2,5-DHF
(entry1) is oxidized selectivelyyielding the correspond-
ing ketone (94%), while the rings containing nitrogen
(entry2) and sulfur (entry3) show a strong tendency
toward side reactions resulting in a set of unidentified
products.
Comparison of the several oxygen-containing rings
presented in Table 4 allows one to follow an effect of
double bond×s location in the heterocyclic molecule.
Results with 2,3-DHF (entry4) and 3,4-dihydro-2 H-
pyran (entry 5) show that double bonds located nearer
to the oxygen atom exhibit an increased disposition
towards cleavage. Indeed, oxidation of 2,3-DHF pro-
ceeds exclusively via the cleavage route. It leads to 71%
of allyl formate in the products:
ꢀ8†
Besides, a set of other formates was identified as a result applied to a varietyof alkenes including aliphatic, cyclic,
of addition of the intermediate carbene I [Equation (8)] heterocyclic alkenes and their derivatives. The oxida-
to the components of reaction mixture. No sign of tion proceeds non-catalytically in the temperature range
butyrolactone was detected. Oxidation of 3,4-dihydro- of 150 2508C yielding ketones and aldehydes as main
2H-pyran also proceeds primarily via the cleavageroute, products. Although the reaction selectivitydepends
giving 48% of 3-butenyl formate. But in this case, a significantlyon the alkene structure and composition,
significant contribution of a non-cleavage route is also each type of alkenes was shown to include compounds
observed, which is evidenced bythe presence of 31% of
d-valerolactone in the products.
Unlike that, oxidation of 2,5-DHF (entry1) and 4,7-
whose oxidation proceeds selectivelyyielding 90 99%
of carbonyl compounds.
Trying to test as many substrates as possible, we did
dihydro-1,3-dioxepin (entry 6), having more distant not have an opportunityto studyeffect of temperature
location of double bonds (position 3), proceeds essen- and N2O concentration on the reaction performance. As
tiallywithout cleavage leading in both cases to the
a first approximation one mayassume this effect to
formation of corresponding ketones with 94% selectivity. follow the kinetics observed with the oxidation of
Note that oxidation of 3,4-dihydro-2H-pyran has been cyclopentene and cyclohexene.[8,11]
studied earlier byBridson-Jones et al. [9] Theyfound that
Due to evolution of high energy, N2O oxidation may
the reaction proceeds via non-cleavage route giving cause cleavage of an alkene molecule over the double
small amount of d-valerolactone as the onlyoxidation
bond. This undesirable process increases the number of
reaction products and decreases the selectivity. But in
the case of terminal alkenes, where this process is most
intensive, it maydeserve a special interest as a wayfor
generating carbenes, which maybe used for conducting
fine synthetic reactions.
product. The distinction from our results maybe
[9]
explained bymore severe reaction conditions in ref.
,
which might cause fast secondarytransformations of 3-
butenyl formate.
With regard to a possible practical application of
nitrous oxide in chemical reactions, it is worth mention-
ing that N2O is an inexpensive compound. Presentlyit is
Conclusion
Results of the substrate screening presented above show used for medical application and prepared mainlyby
that liquid-phase oxidation with nitrous oxide can be decomposition of ammonium nitrate:
272
¹ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
Adv. Synth. Catal. 2004, 346, 268 274

Liquid Phase Oxidation of Alkenes with Nitrous Oxide
FULL PAPERS
GC analysis of the liquid phase products was typically
performed at the programmed elevation of temperature from
408C to 2508C with a capillarycolumn (50 m, 0.2 mm, SE-52
phase) using an FID. In most cases, authentic compounds or
their isomers were used as calibration standards. In the case of
low selective reactions, the analysis was usually limited by
identification of main products.
GCMS analysis was performed using VG Analytical Ltd.
7070 HS, and Varian Saturn 2000 instruments equipped with a
set of capillarycolumns. The type of a column as well as
operation conditions were selected depending on the reaction
under study, so as to provide more efficient separation and
identification of the products.
ꢀ9†
Recently, an efficient process for N2O preparation has
been developed using direct oxidation of ammonia:
ꢀ10†
The process has been successfullytested with a pilot
unit.[15] The reaction is accomplished using a Mn/Bi/Al
oxide catalyst, and 87 88% selectivity to nitrous oxide
has been achieved at almost complete conversion of
ammonia. According to estimation,[16] the cost of active
oxygen in N2O produced bythis method is 4 times lower
than its cost in H2O2. This fact coupled with remarkable
oxidation chemistrymakes nitrous oxideto be especially
attractive oxygen donor, and stimulates further studies
in this promising field.
NMR analysis of reaction products was performed using a
resulting reaction mixture without its anyfurther treatment or
modification. 1H and 13C NMR spectra were recorded at 400.13
and 100.61 MHz, respectively, using a Bruker MSL-400
spectrometer. The following operating conditions were used:
sweep width 6 kHz (1H) or 25 kHz (13C), 10 208 pulse of 1
2 ms (1H), 458 pulse of 12 ms (13C), relaxation delay5 60 s. To
provide an increased accuracyof measurements, large scan
numbers were collected, in the range of 102 À 104 scans
depending on the composition and concentration of the
products.
Warning. Oxidation of alkenes with N2O involves no
[8]
free radicals
and therefore is less explosive as
compared with similar reactions involving O2. However,
one should remember that nitrous oxide can form
explosive mixtures with organic substrates,[17,18] and
should use precautionarymeasures to ensure a safe
work.
Quantitative 13C NMR relative intensitymeasurements
were made with inverse gated proton decoupling (to avoid the
nuclear Overhauser effect) and long relaxation delays. These
results, together with the GC data, were used for calculating
alkene conversions and reaction selectivities.
High purityorganic substrates were used in the work,
purchased from Aldrich, Fluka and ACROS. Medical grade
nitrous oxide (99.8%) was purchased from Cherepovets Azot
Co. (Russia). The latter was supplied in cylinders in a liquefied
form under equilibrium pressure of about 50 atm.
Experimental Section
Oxidation of alkenes with N2O was performed batchwise in a
stainless-steel Parr autoclave reactor of 100 c.c. capacity,
equipped with a stirrer and manometer. The vessel was
typically charged with 25 c.c. of a liquid substrate. In order to
remove dioxygen, the system was blown off with nitrous oxide
Acknowledgements
fed from a cylinder, and then an initial N2O pressure, P0N O, was
2
We thank Dr. V. A. Utkin and Dr. V. A. Rogov for performing
GCMS analysis of the reaction products. We also thank Dr.
K. P. Bryliakov for performing some NMR analysis. A part of
this work was supported by a grant within RAS Presidium
Program9.3, 2003.
set at 10 or 25 atm. The vessel was closed and heated (at 68C/
min ramp) to the reaction temperature 150 2508C. Due to
heating, the pressure increased to 30 100 atm depending on
the initiallyadmitted amount of N 2O and an equilibrium
pressure of the alkene. When the reaction was completed, the
vessel was cooled to room temperature and, after performing
analysis of the gas phase composition, the pressure released
slowly.
In manycases, in particular with gaseous or solid alkenes, the
oxidation was conducted in solvents. The type of solvent
(benzene, cyclohexane or acetonitrile) and amount of a
dissolved alkene are given in Tables 1, 3, 4 together with the
corresponding experimental results. All the solvents were
shown to be inert with respect to N2O oxidation.
Reaction products were analyzed using the GC, GCMS and
NMR methods. GC analysis of the gas phase composition
(N2O, N2, CO, CO2, low hydrocarbons) was performed at room
temperature with a Cristall-2000 instrument using a TCD and a
packed column filled with Poropak Q. For a more accurate
measurement of small CO and CO2 amounts, these compounds
were hydrogenated over a nickel catalyst and then analyzed as
methane using an FID. However, even with this sensitive
method, no complete oxidation products were detected. In all
cases COx concentration was less than 0.001 mol %.
References
[1] A. K. Uriarte, M. A. Rodkin, M. J. Gross, A. S. Kharito-
nov, G. I. Panov, in Proc. 3rd Intern. Congress on Oxida-
tion Catalysis, R. K. Grasselly, S. T. Oyama, A. M.
Gaffney, J. E. Lyons (Eds.), Stud. Surf. Sci. Catal.,
Elsevier Science B. V. 1997, 110, 857.
[2] G. I. Panov, A. S. Kharitonov, V. I. Sobolev, Appl. Catal.
A: General. 1993, 98, 1.
[3] A. Reizman, M. H‰fele, G. Emig, Trends in Chem. Eng.
1996, 3, 63.
[4] G. Panov, A. Uriarte, M. Rodkin, V. Sobolev, Catal. To-
day 1998, 4, 365.
[5] G. Centi, S. Perathoner, F. Vazzana, CHEMTECH 1999,
48.
[6] G. Panov, CATTECH 2000, 4, 8.
Adv. Synth. Catal. 2004, 346, 268 274
asc.wiley-vch.de
¹ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
273

E. V. Starokon et al.
FULL PAPERS
[7] A. Leontiev, O. Fomicheva, M. Proskurina, N. Zefirov,
Usp. Khim. 2001, 70, 107.
[8] G. I. Panov, K. A. Dubkov, E. V. Starokon, V. N. Par-
mon, React. Kinet. Catal. Lett. 2002, 76, 401.
[9] F. S. Bridson-Jones, G. D. Buckley, L. H. Cross, A. P.
Driver, J. Chem. Soc. 1951, 2999.
[10] F. S. Bridson-Jones, G. D. Buckley, J. Chem. Soc. 1951,
3009.
[11] K. A. Dubkov, G. I. Panov, E. V. Starokon, V. N. Par-
mon, React. Kinet. Catal. Lett. 2002, 77, 197.
[12] M. D. Su, H. Yi. Liao, W. S. Chung, S. Y. Chu, J. Org.
Chem. 1999, 64, 6710.
[13] V. I. Avdeev, S. Ph. Ruzankin, G. M. Zhidomirov, Chem.
Commun. 2003, 42.
[14] W. Kirmse, Carbene Chemistry, Chapter 2, Academic
Press, New York, London, 1964.
[15] A. S. Noskov,
I. A. Zolotarskii,
S. A. Pokrovskaya,
V. N. Korotkikh, E. M. Slavinskaya, V. V. Mokrinskii,
V. N. Kashkin, Chem. Eng. J. 2003, 91, 235.
[16] A. K. Uriarte, Stud. Surf. Sci. Catal. 2000, 130, 743.
[17] G. Panetier, A. Sicard, Proc. 5th Symposium on Com-
bustion, Pittsburgh, USA, 30 Aug. 3 Sept. 1954. Book of
Abstracts, 1955, p. 620.
[18] B. B. Brandt, L. A. Matov, A. I. Rozlovskii, V. S. Khai-
lov, Khim. Prom. 1960, 5, 67.
274
¹ 2004 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim
asc.wiley-vch.de
Adv. Synth. Catal. 2004, 346, 268 274