[0001] This invention relates to the oxidation of olefinic carbon-carbou double bonds to
carbonyl groups. In another aspect, it relates to the use of a diluent system comprising
at least two liquid phases with at least one being aqueous. In another aspect, it
relates to the use of a two-phase diluent system with one being an aqueous phase and
another being an organic phase. In yet another aspect, it relates to the use of a
Pd/Cu/alkali metal or alkaline earth metal chloride catalyst in conjunction with a
multi-phase diluent system for the oxidation of olefinic carbon-carbon double bonds
to carbonyl groups. In yet another aspect, this invention relates to the addition
of a suitable surfactant to such a reaction system.
[0002] The Wacker-type oxidation of ethylene to acetaldehyde using a palladium chloride/cupric
chloride/hydrochloric acid catalyst in an aqueous solution has been modified and applied
to the synthesis of methyl ketones 11 - terminal olefins.. However, major problems
have been encountered in using Wacker-type oxidation in the oxidation of higher olefins.
One problem Ls in of reduced rates of reaction due to the low solubility of the olefin
in the aqueous medium. Another major problem is the concomitant secondary oxidation
of the ketone product which leads to poor selectivities and poor yield of desired
product.
[0003] The present invention, however, has solved these problems of the Wacker-type oxidation
of the higher olefins by resorting to "phase transfer" techniques and the addition
of a suitable surfactant. The instant invention reacts the olefinic hydrocarbon reactant
to be oxidized in the presence of free oxygen in a multi-phase diluent system, preferably
a two-phase system with one phase aqueous and the other organic. The catalyst involved
is a Pd/Cu/alkali metal or alkaline earth metal chloride catalyst with the palladium
being either palladium or a palladium compound and the copper component being either
a cuprous or cupric compound. It should also be noted that the HC1 used in conventional
Wacker oxidation reactions to mairitain adequate conversion levels of the olefinic
reactant is not part of the process of the present invention due to its deleterious
effect on the oxidation reaction according to the instant invention. An alkali metal
or alkaline earth metal chloride has been found, however, to favorably increase the
selectivity of the instant invention. An additional component of the present invention,
in a specific embodiment, which further increases the conversion and selectivity of
the oxidation reaction is the addition of a suitable surfactant to the reaction system.
[0004] An object of the present invention, therefore, is to increase the conversion and
selectivity of higher olefins in an oxidation process.
[0005] Another object is to increase the conversion and selectivity of higher olefins in
an oxidation process by effectively removing the carbonyl compound product from the
locus of the oxidation process.
[0006] Another object is the use of an improved diluent system in the oxidation of higher
olefins.
[0007] Yet another object is to provide for the use of a reaction promoter for increasing
the conversion and selectivity of an oxidation process for higher olefins.
[0008] Other objects, aspects, and the several advantages of this invention will be apparent
to those skilled in the art upon a study of this disclosure and the appended claims.
Detailed Description of the Invention
I. Olefinic Hydrocarbon Reactant
[0009] The instant invention is concerned with a process for the conversion of olefinic
carbon-carbon double bonds to carbonyl groups by oxidation of said olefinic compound
in a reaction system comprising at least two liquid phases wherein at least one liquid
phase is an aqueous phase.
[0010] In a specific embodiment of the instant invention, the oxidation process is carried
out in the presence of a surfactant in order to increase the conversion and selectivity
of the olefin reactant.
[0011] The olefinic hydrocarbon reactant which is oxidized according to the process of the
instant invention can be selected from the groups consisting of acyclic olefinic compounds
containing from 3-20 carbon atoms per molecule and having 1, 2, or 3 olefinic carbon-carbon
double bonds per molecule and cyclic olefinic compounds containing from 5-20 carbon
atoms per molecule and having 1, 2, or 3 olefinic carbon-carbon double bonds per molecule.
Within the limitations described above, suitable olefinic hydrocarbon reactants can
bel repre ented by the general formula RCH=CHR' wherein R and R' are selected from
the group consisting of hydrogen, alkyl, alkenyl, alkadienyl, cycloalkyl, cyclo- alkenyl,
and cycloalkadienyl radicals and wherein R can be the same or differ- ent from R'
and wherein R and R' taken together can form an alkylene or alkeny- lene alkadienylene
radical thus forming a cyclic system. The term "olefinic carbo-carbon double bond"
as used herein is not meant to include those carbon- carbe double bonds which arc
part of an aromatic carbocyclic system of alte hating single and double bonds.
[0012] Examples of suitable monoolefinic compounds include propylene, 1-butene, 2-butene,
1-pentene, 2-pentene, 1-hexene, 2-hexene, 3-hexene, 1-octen, 1-decene, 1-dodecene,
1-hexadecene, 1-octadecene, 1-eicosene

[0013] Examples of suitable diolefinic compcands include 1,3-butadiene, 1,3-pencadiene,
1,5-hexcadiene, 4-vinyl cyclohexene, 1,5-cyclooctadiane, 1,9-decadiene, 1,7-octadiene,
1,3-cycloheptadiene, and the like.
[0014] Examples of suitable triolefinic compounds include 1,5,9-cyclododecatriene, cycloheptatriene,
1,6-diphenyl-1,3,5-hexatriene, and the,like.
[0015] It is preferred however, that at least one olefinic carbon-carbon double bond is
in the terminal position, i.e., the preferred olefinic reactant is a terminal olefinic
hydrocarbon.
II. Catalyst System
[0016] The catalyst utilized according to the instant invention for the oxidation of olefinic
hydrocarbons to carbonyl compounds is made up of three components: (1) a palladium
component, (2) a copper component, and (3) an alkali metal or alkaline earth metal
chloride component.
(1) Palladium Component
[0017] The palladium component of the catalyst system of the instant invention can be palladium
metal such as finely divided palladium powder or a palladium compound. Examples of
suitable palladium compounds include allyl palladiu chloride dimer [C
3H
SPdCl]
2, dichlorobis(triphenylphosphine)palladium(II), palladium(II) acetate, palladium(II)
acetylacetonate, tetrakis(triphenylphosphine)palladium(0), pslladium(II) chloride,
palladium(II) iodide, palladium(II) nitrate, and the like. Mixtures of the above palladium
compounds can also be utilized as the palladium component of the instant catalyst
system if so. desired.
(2) Copper Component
[0018] The copper component of the instant catalyst system can be provided by utilizing
a cuprous or cupric compound or mixture thereof. A wide variety. of copper compounds
can be utilized to provide the copper component of the instant catalyst system. Specific
examples of suitable copper compounds include copper(I) acetate, copper(II) tetyinceteur
copper(I) bromide, copper(I) chloride, copper(II) chloride, copper(I) iodide, copper(II)
nitrate, and the like. Mixtures of suitable copper compounds can also be employed
to provide the copper component of the instant catalyst system if so desired.
(3) Alkali Metal or Alkaline Earth Metal Chloride
[0019] The third component of the catalyst system of the instant invention is a chloride
of an alkali metal or an alkaline earth metal. Specific examples of suitable alkali
metal chlorides include lithium chloride, sodium chloride, potassium chloride, rubidium
chloride, and cesium chloride. Examples of suitable alkaline earth metal chlorides
include calcium chloride, barium chloride, strontium chloride, magnesium chloride,
and beryllium chloride. Mixtures of the above metal chlorides can be employed as the
thirc component of the catalyst system if so desired.
[0020] The ratios of the various catalyst components can be expressed in terms of a molar
ratio of copper to palladium and a molar ratio of chloride ion derived from the alkali
metal or alkaline earth metal chloride to palladium. The molar ratio of copper component
to palladium component in tt ; instant catalyst system is broadly from 1/1 up to 200/1
and preferably from 2/1 up to 50/1. The molar ratio of chloride ion derived from the
alkali me or alkaline earth metal chloride to palladium is broadly from 5/1 to 1,000/1
and preferably from 20/1 up to 400/1.
[0021] The amount of catalyst employed according to the instant invention can be expressed
in terms of the molar ratio of olefinic hydrocarbon reactan't to palladium component
of the catalyst system. Broadly, the molar ratio of olefinic reactant to palladium
component is from 5/1 up to 1,000/1 and preferably from 10/1 up to 250/1.
[0022] in a specific emlediment of the instant invention, the oxidation reac- tion is carried
out in the presence of an additional surfactant component in order to increane conversion
and selectivity of the olefin reactant. This additional surfactant component of the
reaction system according to the instant invention is a compound selected from one
of the five groups to be described more fully below. It will be recognized from the
description of the five groups of compounds below that said compounds generally would
be ! expected to exhibit surface-active properties, and, as such, they may be called
surfactants. However, the term "surfactant" encompasses a very broad class of compounds,
and it has been discovered that not all surfactants are suitable for use in the instant
invention. Nevertheless, for convenience and simplicity, the suitable compounds that
can be employed according to the instant invention and described more fully below
will be termed surfactants herein. At the present time, it is not known whether these
compounds behave as phase-transfer catalysta such as is taught in the art or whether
they are functioning as micellar catalysts, a feature also disclosed in the prior
art. Because of this uncertainty in the mode of action of these compounds in the instant
invention and for convenience as mentioned above, the following compounds will merely
be described herein as surfactants. ;
[0023] A suitable surfactant for use in the reaction system of the instant invention is
selected from one of the five following groups:
(A) Quaternary ammonium salts of the general formula (R''')4N+X- wherein R"' is an alkyl radical of from 1 to 20 carbon atoms and wherein the total
number of carbon atoms in said quaternary ammonium salt is from 8 to 30 carbon atoms
broadly and preferably from 16 to 22 carbon atoms; and wherein X-is selected from
the group consisting of Br-, Cl-, I-, F-, R"'CO2-, QSO3-, Br4-, HSO4- wherein Q is an aryl or alkaryl radical of 6 to 10 carbon atoms. It will be noted
that a variety of anions are suitable as the X- component of the quaternary ammonium salts. Specific examples of quaternary ammonium
according to the general formula given above include cetyltrimethylamme (hexadecyltrimethylammonium)
bromide, tetraheptylammonium bromide, cetyltrimethylammonium stearate, benzyltributylammonium
chloride, benzyltri- ethylammonium bromide, benzyltrimethylammonium bromide, phenyltrimethylammonium
bromide, phenyltrimethylammonium iodide, tetrabutylammonium bromide, tetrabutylammonium
chloride, tetrabutylammonium hydrogen sulfate, tetrabutylammonium iodide, tetraethylammonium
bromide, tetrabutylammonium fluoride, tetrabutylammonium tetrafluoroborate, and the
like.
(B) Alkali metal alkyl sulfates of the general formula R'v OSO3M wherein R'v is an alkyl radical of from 10 to about 20 carbon atoms and wherein
M is an alkali metal. Examples of suitable compounds according to the general formula
for the alkali metal alkyl sulfates include lithium decylsulfate, potassium dodecylsulfate,
sodium dodecylsulfate, sodium hexadecylsulfate, potassium hexadecylsulfate, rubidium
dodecylsulfate, cesium dodecylsulfate, sodium octadecylsulfate, potassium octadecylsulfate,
potassium eicosylsulfate, sodium eicosylsulfate, and the like.
(C) Alkali metal salts of alkanoic acids of the general formula R'v C02M wherein R'v and M have the same meaning as given above for the compounds of (B).
Examples of suitable alkali metal salts of alkanoic acids include lithium decanoate,
sodium dodecapoate, potassium dodecanoate, rubidium dodecanoate, cesium dodecanoate,
sodium hexadecanoate, potassium hexadecanoate, sodium octadecanoate, potassium octadecanoate,
sodium eicosenoate, potassium eicosenoate, and the like.
(D) Alkali metal salts of alkaryl sulfonic acids of the general formula

wherein R'v and M have the same meaning as given above and wherein Rv is an alkyl radical of 1 to 4 carbon atoms and wherein n is 0 or an integer of from
1 to 4. Specific examples of compounds within the (D) group include sodium.dodecylbenzenesulfonate,
potassium dodecyloxy resulfonate, lithium dodecylbenzenesulfonate, sodium tetradecyl-
benzenesulionate, potassium hexadecylbenzenesulfonate, rubidium dodecylbenzene- suafonate,
cesium dodecylbemenesulfonate, sodium octadecylbenzenesulfonate, potassium octadecylbenzenesulfonate,
sodium eicosylbenzenesulfonate, potassium dodecyltolucnesulfonate, sodium dodecylxylenesulfonate,
and the like.
(E) 1-Alkyl pyridinium salts of the general formula

wherein R'v and X have the same meanings as described above. Examples of suitable
1-alkyl pyridinium salts include 1-dodecylpyridinium para-toluenesulfonate, 1-dodecylpyridinium
chloride, 1-hexadecylpyridinium chloride, 1-hexadecylpyridinium para-toluenesulfonate,
1-decylpyridinium chloride, 1-hexadecylpyridinium bromide, 1-tetradecyl- pyridinium
chloride, 1-octadec.ylpyridinium chloride, 1-eicosylpyridinium chloride, 1-octadecylpyridinium
benzenesulfonate, and the like.
[0024] The amount of surfactant compound selected from groups (A) through which is utilized
according to the instant invention can be expressed in terms of a mole ratio based
on the palladium component of the catalyst system. Broadly, the mole ratio of surfactant
to palladium compound will be from 0.01/1 to 10/1 and preferably from 0.1/1 to 3/1.
III. Diluent System
[0025] As indicated above, the oxidation of the olefinic hydrocarbon according to the instant
invention is carried out in the presence of a diluent comprised of at least two liquid
phases (preferably only two), at least one of which is-an aqueous phase.
[0026] The nonaqueous phase will hereinafter be termed the organic phase. Said organic phase
should be relatively inert to the oxidation conditions, of course, and also relatively
inert to hydrolysis-type reactions. Furthermore, it is apparent that if at least two
phases are present, at least one of which is an aqueous phase, that the organic diluent
utilized must have somewhat limited solubility in the aqueous phase.. Within these
general requirements, a rather broad range of organic compounds can be utilized to
form the organic phase according to the instant invention. Generally speaking, suitable
compounds can be found in the classes of compounds described as aromatic hydrocarbons
or alkyl-substituted aromatic hydrocarbons, halogenated aromatic compounds, and esters
of aromatic carboxylic acids although the latter may be less preferred because of
a tendency toward hydrolysis of the ester group in certain instances. In addition,
it has been found that com- pounds such as nitrobenzene and benzonitrile, commonly
utilized as solvents for many organic reactions, show a definite inhibitory effect
on the reaction of the instant invention presumably by complexing of one or more catalyst
components. Specific examples of suitable organic diluents include cyclohexane, hexane,
benzene, toluene, chlorobenzene, methylbenzoate, bromobenzene, 1,2,4- trichlorobenzene,
ortho-dichlorobenzene, sulfolane, ortho-xylene, para-xylene, meta-xylene, methylcyclopentane,
dimethyl ortho-phthalate, and the like. Mixtures of the above organic diluents may
be utilized in some cases as desired. Generally speaking, the choice of the organic
diluent may be often determined based on the difference in boiling points expected
between the product of the oxidation reaction and the organic diluent so as to facilitate
separation of the components of the reaction mixture.
[0027] The amounts of aqueous phase and organic diluent phase based on the starting olefinic
reactant can vary over a wide range, and suitable broad range includes from 20 to
0.2 volumes of organic diluent per volume of olefinic hydrocarbon renctant and preferably
from 5 to 1 volumes of organic diluent

hydrocar a reactant and preferably from 5 to 1 per volume of olefinic hydrocarbon
reactant. It is worth pointing out some predictions relating to the expected effects
of the volume of aqueous phase on the oxidation reaction of the instant invention.
First, if the aqueous phase volume becomes too small, the concentration of the catalyst
components in the aqueous phase may cause a salting-out effect on the olefinic hydrocarbon
reactant, thus greatly slowing down the reaction rate wherein the olefinic hydrocarbon
reactant is oxidized to the desired carbonyl compound. Secondly, if the aqueous phase
becomes too large, the concentration of catalyst components may be so dilute that
the reaction with the olefinic hydrocarbon may also be greatly slowed. However, it
can be seen that a judicious choice of the optimum amount of the aqueous phase for
high conversion levels of the olefinic hydrocarbon reactant can readily be determined
by a.few well-chosen experiments.
[0028] At present, it is believed that the primary function of the organic phase in the
reaction system of 'the instant invention is to greatly increase the selectivity to
the desired carbonyl compound by effectively removing the carbonyl compound product
from the locus of the oxidation reaction thereby preventing side reactions such as
isomerization and/or further oxidation of the carbonyl compound. However, this explanation
is to be treated merely as a theory of the mode of action of the organic phase in
the reaction and the instant invention should not be bound to any extent by said theory.
IV. Oxygen
[0029] As indicated previously, the reaction of the instant invention is an oxidation reaction
whereby an olefinic reactant is converted to a carbonyl compound in the presence of
a catalyst and diluent system described above. Thus, the reaction of the instant invention
is carried out in the presence of free oxygen. The oxygen may be supplied to the reaction
mixture essentially as pure oxygen or admixed with other gases which are essentially
inert to the reaction conditons. Air can be utilized as a source of oxygen for the
oxidation reaction of this invention. As is generally true for most oxidation reactions,
the reaction of the instant invention can be exothermic and thus some care should
be exercised in the amount of oxygen present in the reaction system. For this reason
and also to improve control of the temperature of the reaction, it is preferred to
add oxygen or the gaseous mixture containing oxygen to the reaction zone incrementally
such that explosive ranges of oxygen concentration do not develop. The pressure of
oxygen utilized for the instant invention can broadly be from 2 up to 250 psig and
preferably from 10 to 100 psig above the autogenous pressure at the temperature utilized.
;
V. Keaction Conditions
[0030] The temperature utilized in the instant invention is broadly from 20-200°C and preferably
from 60-150°C. It can also be noted that the particular temperature employed may be
dependent somewhat on the olefinic hydrocarbon reactant. For example, at relatively
high temperatures, a lower molecular weight olefinic hydrocarbon reactant may tend
to be very insoluble in the aqueous phase of the two-phase system of the instant invention,
thus causing a reduced conversion of the olefinic hydrocarbon reactant, On the other
hand, a higher molecular weight olefinic reactant may be able to tolerat a higher
reaction temperature and still maintain a reasonable degree of solubility in the aqueous
phase and thus achieve a good degree of conversion at the higher temperature.
[0031] The time employed for the reaction according to the instant invention can vary over
a wide range and will to some extent depend on the desired degree of conversion of
the olefinic hydrocarbon reactdnt. Generally, a time period such as from 30 minutes
to 8 hours will be employed in the instant invention.
[0032] Because the oxidation reaction according to the instant invention is carried out
in the presence of a diluent system comprising at least two liquid phases, it is expected
that good stirring will be of benefit and conventional means of achieving good agitation
and contact between the liquid phases can be employed, as taught by the prior art.
[0033] The charge order of the reaction components and catalyst components is not particularly
critical in the process of the instant invention. However, the presence of oxygen
in the reaction mixture prior to heating of the mixture to the desired reaction temperature
appears to promote higher selectivity to the desired carbonyl compound.
[0034] The process of the instant invention can be carried out in either a batch or continuous
process.
[0035] Reaction vessels utilized in the process of the instant invention should, of course,
be able to withstand.the oxidizing conditions which are present. For this reason,
glass-lined, tantalum, or titanium-clad vessels and conduits are recommended for use
in the process of this invention.
VI. Reaction Mixture Workup
[0036] A variety of methods can be utilized to recover the products, un- reacted olefinic
hydrocarbon starting materials, and the catalyst in the aqueous phase in the instant
invention. For example, the reaction mixture can be admixed with a saturated aqueous
sodium chloride solution followed by extraction of the mixture into diethyl ether.
The ether extract can then be distilled or treated in such a manner as to remove the
ether leaving the organic residue containing the product and any unreacted olefinic
hydrocarbon reactant. Said residue can then be subjected to fractional distillation
procedures to recover the various components.
[0037] Another method of reaction mixture workup can involve fractional distillation of
the entire reaction mixture to separate the components into various fractions and
said distillation kettle bottoms can be recycled to the reaction zone as that portion
containing essentially all of the catalyst system for the reaction.
[0038] Another method of treating the reaction mixtute is to conLact the entire mixture
with a lower alkane such as n-pentare then separating the aqueous phase from the organic
phase followed by fractional distillation of the organic phase to recover the products
and any unreacted olefinic hydrocarbon reactants. The aqueous phase can be recycled
to the reaction zone as described above since it contains essentially all of the catalyst
components.
VII. Product Utility
[0039] As indicated earlier, the reaction of the instant invention provide a process for
the conversion of olefinic hydrocarbon reactants to carbonyl compounds. Said carbonyl
compounds are ketones. If the olefinic hydrocarbon reactant contains two carbon-carbon
double bonds, the product can be an unsatnrated monoketone or a diketone. Furthermore,
the unsaturated monoketor can b
3 recycled to the reaction zone for conversion to the diketone. Similar. a triolefinic
reactant can be converted to intermediates such as unsaturated mono- or diketones
and ultimately to a triketone. Ketones from the olefinic hydrocarbon reactants described
in part I above have generally well-known .utilities. For examole, they can be utilized
as solvents (methyl ethyl ketone) or as intermediates in the synthesis of other chemical
compounds (pinacolone).
VIII. Examples
[0040] In all of the runs that are described in the following examples, the reaction vessel
utilized in each of the runs was a 250 ml Fisher-Porter

compatibility bottle equipped with a magnetic stirrer. Generally, the both was charged
with the catalyst system, the diluents, and the olefinic reactar after which the bottle
was placed in an oil bath, pressured to about 30 ps g with oxygen, and then heated
to the desired temperature. During the reaction period, the bottle was prossured intermittently
at about 10-30 minute intervals to nn oxygen pressure of about 80-120 psig. Usually
the reaction mixture was recovered from the bottle reactor by cooling the reactor,
ventin, the gas phase and pouring the mixture into about 500 ml of water. This miature
was then extracted into diethyl ether and the ether extract washed with water and
dried over magnesium sulfate. The dried ether extract was then filtered and the ether
stripped off in a distillation step. The residue remaining after the removal of the
ether was then analyzed by gas-liquid phase chromato- graphy. Significant deviations
from the above general procedures will be noted where appropriate in the respective
examples that follow.
Example I
[0041] In a control run (Run 1), the 250 ml Fisher-Porter aerosol compatibility bottle was
charged with 1-hexene (200 mmoles), methyl benzoate (50 ml), water (50 ml), palladium(II)
chloride (5 mmoles), and cupric chloride (20 mmoles). The reactor was pressured to
80 psig (551 kPa) with oxygen and heated to 105°C. The reaction was continued for
five hours with intermittent pressuring with oxygen as.described above. Analysis of
the reaction mixture by gas-liquid phase chromatography indicated a 55 percent conversion
of 1-hexene with an 87 percent selectivity to a mixture of hexanones, 55 percent 2-hexanone
and 45 percent 3-hexanone.
[0042] Another control run (Run 2) was carried out under essentially the same conditions
described above for Run 1 with the exception that 1.8 mmoles of hexadecyltrimethylammonium
bromide was added to the reaction mixture. In this run (Run 2), a 64 percent conversion
of 1-hexene was achieved with a 94 percent selectivity to hexanones, 62 percent 2-hexanone
and 38 percent 3-hexanone.
[0043] Note that both runs did not employ an alkali metal or alkaline earth metal chloride
catalyst component.
[0044] Hydrolysis of the methyl benzoate codiluent was observed in the above runs and caused
some difficulty in product isolation.
[0045] The results of control Runs 1 and 2 described above indicate the improved olefin
conversion and selectivity to carbonyl compound products achieved in the oxidation
of said.olefinic reactant by the presence of a surfactant.
Example II
[0046] A number of other runs were carried out utilizing 50 ml of chlorobenzene and 50 ml
of water as the diluent system for the reaction. In these runs, 200 mmoles of 1-hexene
was utilized as the olefinic hydrocarbon reactant, the temperature was 105°C and the
oxygen pressure was about 80 psig (551 kPa) with 5 mmoles of palladium(II) chloride.
Each run also utilized 1.8 mmoles of hexadecyltrimethylammonium bromide as the surfactant
component and a reaction period of 5-6 hours. Other components of the catalyst system
utilized in the runs of this example and the results obtained in the runs (by gas-liquid
phase chromatography analysis) are presented in Table r below.

[0047] Although the results shown for Run 5 appear to be quite good, the analysis of the
product mixture revealed that production of chlorinated hexanones had become significant
in this run Thus, the needed additional chloride ion cannot be furnished by simply
increasing the CuCl
2 level because of side reacticn(s) such as chlorination of the product ketones.
[0048] The low conversion in Run 8 is believed to be due to a "salting out' effect of high
salts concentration on the water-solubility of 1-hexene.
Example III
[0049] Other runs were carried out utilizing the same apparatus and procedure as described
above and utilizing the catalyst system shown for Run 7 of Table I in Example II.
These runs of Example III examined the effect of changing the level of the surfactant,
hexadecyltrimethylammonium bromide, in the reaction mixture. The results of these
runs are presented in Table II below. Run 7 is included for convenience in comparing
the results.

[0050] The results shown in Table II indicate the significantly higher conversion of hexene
achieved according to the instant invention (Run 7) compared to that obtained in Run
13. Furthermore, it is shown in Run 14 that a doubling of the surfactant level did
not significantly change the hexene conversion.
Example IV
[0051] Two additional control runs for 1-hexene oxidation were carried out utilizing the
catalyst system of Run 7 of Example II above in the same type of apparatus and with
the same general procedure described in the earlier ruhs. Run 15 utilized 1.8 mmoles
of hexadecyltrimethylammonium bromide as the surfactant component. However, Run 15
also utilized the addition of 60 mmoles of hydrogen chloride to the catalyst system.
The addition of the HC1 had a dramatic effect on the oxidation reaction. No oxygen
uptake of the system was observed. This result is very different from that observed
in the conventional Wacker oxidation reactions which require incremental additions
of HCl to maintain adequate conversion levels of the olefinic reactant.
[0052] Run 16 utilized the same catalyst system as Run 7 described above, but, in this instance,
employed N,N-dimethyl-1-hexadecanamine hydrochloride as the surfactant component rather
than the quaternary ammonium bromide utilized in Run 7. Use of the tertiary amine
salt in Run 16 drastically reduced the 1-hexene conversion from 73 percent to 6 percent
under otherwise identical conditions. The result of Run 16 also points out the deleterious
effect of acidic conditions on the oxidation reaction according to the instant invention.
Example V
[0053] Additional control runs were carried out utilizing the same apparatus and general
procedures previously described and the catalyst system c Run 7 described above with
the exception that other alkali metal salts were utilized in the catalyst system rather
than lithium chloride. These runs employed 5 mmoles of the palladium(II) chloride,
2'0 mmoles of cupric chloride, a 5-hour reaction time and 105°C reaction temperature.
As previously described, these runs also utilized 50 ml of chlorobenzene and 50 ml
of watr as the diluent system with 1.8 mmol
es of hexadecyltrimethylammonium bromide as the surfactant component. The other alkali
metal salts utilized in these runs are shown in Table III below along with the results
obtained in said runs.

[0054] The results of the above control runs (Runs 17-20) demonstrate that the use of alkali
metal salts other than the chlorides provide significantly inferior results in the
oxidation reaction according to the instant invention.
Example VI
[0055] Other runs were carried out according to the instant invention utilizing a variety
of organic compounds as the organic phase diluent according to the instant invention.
These runs utilized the general conditions described above for Run 7 in terms of the
amount of 1-hexene olefinic hydrocarbon reactant, catalyst system, surfactant amount
and type, aqueous phase amount, reaction time and temperature. Two runs were included
in this series (Runs 21 and 22) which were carried out without any organic diluent
present in the system. The results of these runs and other runs of this example are
shown below in Table IV. Run 7 is. again included for ease of comparison of the results.

[0056] It is apparent that solvents such as benzonitrile (Run 26) and pyridine (Run 27)
are unsuitable as organic diluents for the oxidation reaction according to the instant
invention. Presumably, such solvents inhibit or retard the oxidation reaction by a
strong complexing of the palladium component in the organic phase. The use of sulfolane
(Run 28) as the organic diluent gave good results but a tendency toward increased
degree of isomerization, i.e., 14 percent.of the ketone product was 3-hexanone. The
use of methylbenzoate (Run 25) is accompanied by some degree of hydrolysis of the
organic diluent as previously mentioned in Example I.
Example VII
[0057] Three runs were carried out according to the instant invention but which utilized
internal olefins rather than 1-olefins as the olefinic hydrocarbon reactant in the
oxidation reaction. These runs utilized the "standard" conditions previously described
(Run 7) in terms of the reaction temperature, time, catalyst system, surfactant component,
and diluent system. Run 29 utilized 2-hexene, Run 30 utilized cis-3-hexene, and Run
31 utilized trons-3- hexene, All three of the above runs gave less than 10 percent
conversion of the olefinic reactant after five hours at 105°C. These results demonstrate
the ,

Example VIII
[0058] The effect of reaction temperature on the oxidation of 1-hexene under otherwise "standard"
conditions previously described (Run 7) was examined in a. series of runs. The temperatures
utilized in this series of runs and the reaction times employed are presented in Table
V below. This table also presents the results obtained in the oxidation runs carried
out as described.

[0059] The product from Run 34 carried out at 150°C contained 13 percent of 3-hexanone while
the runs at lower temperatures (Runs 32, 7, and 33) gave ketone products consisting
of essentially pure 2-hexanone. The nature of the by-products leading to the reduced
selectivity to hexanones in Runs 32 and 33 was not determined but further oxidation
to acids and the like may have occurred. It was somewhat surprising that the conversion
in Run 34 was low but this may have been due to the lower olefin solubility in the
aqueous reaction phase at the elevated temperature. It is presently believed that
for a series of olefins there will be a reaction temperature at which conversion and
selectivity are maximized. Said optimum temperature is probably different for each
olefin in said series and can be easily determined with a few experiments.
Example IX
[0060] Other runs were carried out according to the instant invention which examined the
effect of initial oxygen pressure on the oxidation of 1-hexene carried out at 105°C:
The otherwise "standard" conditions were used in these runs. In the runs of this example,
the initial oxygen pressure was as indicated in Table VI and upon reaching the desired
reaction temperature, the oxygen pressure was increased to 90 psig (620 kPa). When
the oxygen pressure fell to about 60 psig (414 kPa), the reactor was repressured to
about 90 psig (620 kPa). The results obtained in these runs are presented below in
Table VT. Run 7 is again included for comparison.

[0061] In Run 35 above, wherein the reaction mixture was heated to 105°C prior to the introduction
of oxygen, the palladium chloride catalyst component had been reduced to palladium
metal before the mixture achieved the desired reaction temperature. An explanation
for the decrease in selectivity to hexanones in Run 35 is not known at present, but
it is apparent that a positive oxygen pressure is beneficial in achieving high selectivities
to the desired carbonyl oxidation products.
Example X
[0062] Another series of runs was carried out utilizing 1-hexene as the olefinic hydrocarbon
reactant and utilizing the previously described "standard" conditions, i.e., 200 mmoles
of 1-hexene, the palladium(II) chloride/cupric- chloride/lithium chloride (S/20/100
mmoles) catalyst system, 5-hour reaction time, 105°C reaction temperature, and the
usual procedure for adding oxygen. The runs of the instant series were carried out
to examine a variety of compounds as the surfactant component of the reaction system.
Previously described Runs 7, 14, and 16 are included in the results shown in Table
VII below.
[0063] The results shown in Table VII indicate that a variety of compounds can be utilized
as the surfactant according to the process of the instant invention but that surprisingly
a compound which has been known in the art as a "phase transfer catalyst," i.e., tetrabutylphosphonium
chloride of Run 46, is not suitable as a surfactant component in the process of the
instant invention.
Example XI
[0064] Additional runs were carried out which examined the use of compounds other than alkali
metal chlorides as a source of additional chloride ion for the catalyst system. These
runs were carried out utilizing the otherwise "standard" conditions of the previous
runs, such as 5 mmoles of palladium(II) chloride, 20 mmoles of cupric chloride, 1.8
mmoles of the surfactant hexadecyltrimethylammonium bromide, 50 ml of water, 50 ml
of chlorobenzene, and five I hours at 105°C under the usual oxygen addition techniques.
The results of these runs are presented in Table VIII shown below. Previously described
Run 7 is included in the table for purposes of comparison.

[0065] The results shown in Table VIII demonstrat that the alkaline earth metal chlorides
at equivalent total chloride ion levels actually gave slightly higher conversion levels
of the 1-olefinic'hydrocarbon reactant than the alkali metal chlorides. However, selectivities
for the alkaline earth metal chlorides under these conditions were slightly lower
than that achieved with the alkali metal chlorides. It is also apparent that ferric
chloride is unsuited as a source of the chloride ion in the catalyst component wherein
an alkali metal or an alkaline earth metal chloride is utilized. In addition to the
lower conversions and selectivities when utilizing the ferric chloride, there was
also observed an appreciable amount of by-product which was believed to be l-chloro-2-hexanone..
The chlorinated ketone by-product is apparently not produced by free radical-type
chlorination of the ketone product since treatment of 2-hexanone for five hours under
the same conditions did not produce any chlorinated ketone. A possible explanation
for the chlorinated ketone by-product is that the ferric chloride promoted allylic
chlorination of the olefin reactant and that this chlorinated olefin was then oxidized
to the chloroketone.
Example XII
[0066] In the prior art description of the Wacker oxidation process, it is usually indicated
that a wide variety of transition metal salts can be used as the cocatalyst to reoxidize
the reduced palladium metal in the process. In the two-phase oxidation system of the
instant invention such a wide variety of transition metal compounds has not been found
suitable for the replacement of the cupric chloride catalyst component. For example,
replacement of the cupric chloride catalyst component with cobalt chloride, stannous
chloride, mercuric chloride, and ferric chloride gave reaction systems which were
either extremely slow or completely inactive. In addition, attempts to substitute
a variety of other compounds for the palladium(II) chloride catalyst component were
also not very successful. For example, catalyst systems utilizing mercuric acetate,
selenium dioxide, apotassium permanganate, cerium trichloride, titanocene dichloride,
uranyl chloride, molybdenum dioxide, thallium tri- chloride, and niobium pentachloride
were all inactive in the two-phase oxidation system of the instant invention. Substitution
of the palladium(II) chloride by platinum chloride provided a catalyst system which
gave very low conversion in the oxidation of 1-hexene in the two-phase oxidation system
of the instant invention, but this catalyst is believed to be impractical and too
expensive for purposes of this reaction system.
[0067] The poor results achieved in all the runs described above in the instant example
point out and rather clearly define the scape of the suitable catalyst components
for use in the two-phase oxidation system of the instant invention whereby an olefinic
hydrocarbon reactant is converted to a carbonyl compound.
Example XIII
[0068] Another run (Run 54) was carried out according to the instant inven- tion utilizing
the same apparatus as previously described and the same catalyst system as described
for Run 47 of Table VIII in Example XI. However, in the instant run, the surfactant
material utilized was tetrabutylammonium bromide (1.8 mmoles) rather than hexadecyltrimethylammonium
bromide which was the surfactant utilized in Run 47. In other respects, the runs were
essentially the same, i.e., 200 mmoles of 1-hexene was utilized as the olefinic hydrocarbon
reactant and the diluent system was composed of 50 ml of water and 50 ml of chlorobenzene.
The reaction temperature was 105°C for a period of five hours, and, as previously
described, oxygen was intermittently added to the reactor by repressuring the reactor
to about 100 psig during the reaction period.
[0069] The reaction mixture was worked up by pouring the mixture into a saturated sodium
chloride solution and then extracted into diethyl ether. The diethyl ether solution
was dried over magnesium sulfate, filtered, and the ether removed by distillation
to leave 85.5 grams of residue. Said residue was analyzed by gas-liquid phase chromatography
as before which revealed the conversion of 1-hexene was 25.7 percent with a selectivity
to hexanones of 100 percent and the amount of 2-hexanone in the ketone mixture was
98.3 percent. Comparison of the results of Run 54 with those of Run 47 indicate that
tetrabutylammonium bromide was not as effective as hexadecyltrimethylammonium bromide
in achieving good levels of 1-hexene conversion in the oxidation reaction carried
out according to the instant invention.
Example XIV
[0070] Two additional runs were carried out according to the instant invention wherein 1-hexene
was oxidized utilizing the catalyst system of palladium chloride/cupric chloride/sodium
chloride (5/20/100 mmoles) and 1.8 mmoles of hexadecyltrimethylammonium bromide as
the surfactant material. These runs were carried out utilizing the 250 ml Fisher-Porter
aerosol compatibility bottle equipped with a magnetic stirrer which was utilized in
the previous runs. In each run, the reactor was pressured to 207 kPa (30 psig) with
oxygen and heated to 105°C with intermittent, repressuring of the reactor with oxygen
to about 689 kPa (100 psig) during the 5-hour reaction period. The two runs of this
example varied the relative amounts of water and chlorobenzene utilized in the diluent
system. Run 47 of Example XI is also included in the tabulater of results shown below
in Table IX.
[0071] ; The results in Table IX show that the relative amounts of the aqueous and nonaqueous
phases of the diluent system utilized according to the instant invention can have
a significant effect on the conversion of the olefinic hydrocarbon reactant and can
also affect the selectivity of the oxidation reaction to the desired carbonyl compounds.
1. A process for the conversion of the olefinic carbon-carbon double bonds of an olefinic
hydrocarbon reactant to carbonyl groups characterized by contacting under reaction
conditions under such temperature and pressure conditions that the oxidation of the
olefinic reactant takes place, the following components in a reaction system:
(a) oxygen;
(b) a diluent comprising at least two liquid phases wherein at least one liquid phase
is an aqueous phase;
(c) a catalyst consisting essentially of
(1) palladium,
(2) copper and
(3) an alkali metal or alkaline earth metal chloride;
and
(d) a surfactant selected from the group of:
(1) quaternary ammonium salts of the general formula (R''')4N+X-,
(2) alkali metal alkyl sulfates of the general formula R'vOSOzM,
(3) alkali metal salts of alkanoic acids of the gener formula R'vCO2M,
(4) alkali metal salts of alkaryl sulfonic acids of t: general formula

or
(5) 1-alkyl pyridinium salts of the general formula

wherein R' ' ' is an alkyl radical of from 1 to 20 carbon atoms and wherein the
total number of carbon atoms in said quaternary ammonium salt is from about 8 to about
30 carbon atoms; X- is selected from the group consisting of Br-, Cl- , I-, F-, R' ' ' CO2-, QSO3-, BF4-, HSO4- wherein Q is an aryl or alkaryl radical of 6 to 10 carbon atoms; R'v is an alkyl radical of from 10 to about 20 carbon atoms; M is an alkali metal; Rv is an alkyl radical of 1 to 4 carbon atoms and wherein n is 0 or an integer of from
1 to 4; and
(e) an olefinic hydrocarbon reactant.
2. A process in accordance with claim 1) characterized in that said olefinic hydrocarbon
reactant is selected from the group consisting of:
(a) acyclic olefinic compounds containing 3-20 carbon atoms per molecule and having
1,2, or 3 olefinic carbon-carbon double bonds per molecule, and
(b) cyclic olefinic compounds containing 5-20 carbon atoms per molecule and having
1, 2, or 3 olefinic carbon-carbon double bonds per molecule.
3. A process in accordance with claim 1) characterized by the fact that the molar
ratio of copper to palladium is about 1:1 to about 200:1;
the molar ratio of the alkali metal or alkaline earth metal chloride to palladium
is about 5:1 to about 1,000:1;
the molar ratio of said olefinic hydrocarbon reactant to palladium is about 5:1 to
about 1,000:1;
the molar ratio of said surfactant to palladium is about 0.01:1 to about 10:1;
said free oxygen is supplied by the use of air and the pressure of oxygen in the reaction
system is in the range of from about 2 to about 250 psig above the autogeneous pressure
at the temperature utilized; and
said reaction temperature is in the range of about 20 C. to about 200 C.
4. A process in accordance with claim 1) characterized in that said diluent consists
of two phases, one aqueous and the other an organic phase, that said organic phase
is relatively inert to the oxidation conditions employed, inert to hydrolysis-type
reactions, and shows a limited solubility in the aqueous phase.
5. A process in accordance with claim 1) characterized by the fact that said surfactant
is:
hexadecyltrimethylammonium bromide,
sodium dodecylsulfate,
sodium octadecanoate,
sodium dodecylbenzene sulfonate,
tetraheptylammonium bromide,
hexadecyltrimethylammonium octadecanoate,
1-dodecylpyridinium para-toluenesulfonate, or
tetrabutylammonium bromide.
6. A process in accordance with claim 2) characterized in that said olefinic hydrocarbon
reactant is a terminal olefin.
7. A process in accordance with claim 6) characterized in that said olefinic hydrocarbon
reactant is 1-hexene.
8. A process in accordance with claim 4) characterized in that said organic diluent
is chlorobenzene.
9. A process in accordance with claim 1) characterized by the fact that said diluent
is an aqueous phase and
an organic phase with the organic phase being chlorobenzene; said olefinic hydrocarbon
reactant is 1-hexene;
said catalyst is palladium(II) chloride, cupric chloride, and lithium chloride; and
said surfactant is hexadecyltrimethylammonium bromide.