Note: Descriptions are shown in the official language in which they were submitted.
5~
sackground of the Invention
.:
This invention relates to the preparation of ethylidene
diacetate (l,l-diacetoxyethane) by the application of carbonyla-
tion techniques to dimethyl ether and/or methyl acetate in the
presence of hydrogen.
Ethylidene diacetate is a chemical intermediate of great
commercial interest in view of its ready convertibility to a
number of different tonnage chemicals of commerce. By one known
conversion technique, ethylidene diacetate is readily transformed
to vinyl acetate plus acetic acid; see Kirk-Othmer "En`cy`clopedia
of Chemical Technology," (2nd ed.), vol. 21, page 321, Interscience,
New York (1970). By another well-known conversion technique,
ethylidene diacetate can be transformed into acetic anhydride plus
acetaldehyde; see Kirk-Othmer "Encyclo~edia of Chemical Technology,"
(2nd ed.), vol. 8, pages 410-413r Interscience, New York (1965).
Reference is also made to U.S. Patent No. 2r425,389 as indicative
of the flexibility of ethylidene diacetate as a chemical inter-
mediate.
Heretofore, however, the potential of ethylidene di-
acetate as a chemical intermediate has been severely limited by
an absence of economic techniques for its preparation from readily
available, inexpensive raw materials. One technique for ethyli-
dene diacetate production involves the reaction of acetaldehyde
and acetic anhydride to produce ethylidene diacetate as an inter-
mediate for the production o vinyl acetate, a process which has
been employed to a limited extent on a commercial scale; see
"~Iydrocarbon Process." (11), 2~7 (1965). Another technique has
involved the reduction of acetic anhydride with hydrogen; see
Fenton, U.S. Patent No. 3,579,566.
In consequence ethylidene diacetate's potential as a
chemical intermediate has not been realized since its manufacture
-2- ~
~06~ii885
has involved the utilization of quite expensive raw materials
which are today in short supply. In further consequence modern
chemical technology has focused on the utilization of ethylene as
the raw material for the production of acetic anhydride, acetalde-
hyde, vinyl acetate, and acetic acid. Ethylene production, of
course, is contingent upon the use of petroleum fractions which
are equally in short supply and not readily producible directly
from carbon itself or from methane.
The utilization of non-petroleum based raw materials for
10 the production of materials commercially derived from ethylene, ;`~
such as the four enumerated above, has been and is today the sub-
ject of much research primarily focused upon the employment of
carbonylation techniques, l.e., the reaction of carbon monoxide
(with or without the concurrent presence of hydrogen) with organic
materials. By such carbonylation techniques, a variety of
materials have been produced successfully, at least upon a labora-
tory scale. Much of the early work in this area is summarized in ;
Reppe, "Acetylene Chemistry," PB Report-18852-s, Charles A. Meyer
& Co., Inc. (translator), at pages 162 et seq. (1949). However,
in none of this early work was there any indication that ethylidene
diacetate could be obtained by carbonylation techniques. In later
work, in for example, Reppe et al., U.S. Patent No. 2,727,902,
methanol, carbon monoxide, and hydrogen were reacted under car-
bonylation conditions to yield "acetaldehyde dimethyl acetal,"
which is more commonly known as ethylidene dimethyl ether; see
Merck Index, 8th ed., page 37~, Merck & Co., New Jersey (1968).
Indeed, acetals are the only gem-type compounds heretofore known
as being capable of being produced by carbonylation techniques;
see Butter, U.S. Patent No. 3~285,948, and Schultz, U.S. Patent No.
3,689,533.
-3-
~65l3!35
In summary, though much effort has been devoted to
research in the area of carbonylation reactions, in no known
instance have carbonylation techniques heretofore been disclosed
for preparation oE ethylidene diacetate despite the obvious de-
sirability of this material as a chemical intermediate.
Summary of *he'Inv'en't'ion
:.
In accordance with this invention, it has now been found
that ethylidene diacetate can be produced by contacting (a) at
least one member of the group consisting of methyl acetate and di-
methyl ether, (b) carbon monoxide, and (c) hydrogen with a sourceof halide within a reaction zone under substantially anhydrous
conditions. In this invention the halide is selected from the
group consisting of bromide or iodide, or mixtures of bromide and
iodide; iodide is preferred.
The process of this invention can be carried out in vapor
or liquid phase, with liquid phase operation being preferred. In
vapor phase operation the carbon monoxide, hydrogen and methyl - '
acetate (and/or dimethyl ether) together with the source of halide
are introduced ~or contact within the reaction zone. In the liquid
phase preferred embodiment, the carbon monoxide, hydrogen and
methyl acetate (and/or dimethyl ether) reactants are contacted
with a liquid phase reaction medium confined within the reaction
zone and maintained in contact therewith for a time su~ficient to
permit reaction to occur. In this preferred (liquid phase) em-
bodiment, the source of halide can be a component of the liquid
phase reaction medium and need not be introduced together with
the reactants. A portion of the liquid phase reaction medium, now
containing ethylidene diacetate, can then be withdrawn from the
reaction zone and processed for the recovery of ethylidene di-
acetate. The ethylidene diacetate can then be marketed as such
or can be converted to acetaldehyde plus acetic anhydride and/or ~ -
to vinyl acetate plus acetic acid.
--4--
~5885
The over-all reaction that appear~ to occur when methyl
acetate is employed as the reactant can be expressed by the follow-
ing chemical equation:
2 methyl acetate + 2CO ~ H2 > ethylidene diacetate t acetic acid
When dimethyl ether is used as the reactant in lieu of
methyl acetate, the over-all reaction is slightly different and
can be expressed by the following chemical equation:
2 dimethyl ether ~ 4CO + H2 ~ ethylidene diacetate ~ acetic acid
Mixtures of methyl acetate and dimethyl ether can, of
course, be used. Further, although the foregoing equations indi-
cate acetic acid as a primary reaction co-product, other co- ,
products are often obtained instead of or in addition to acetic
acid. The other primary co-products often observed are acetic
anhydride and/or acetaldehyde. The nature and distribution of ' ~
these co-products depends in large measure upon the ratio of carbon -~ '
monoxide to hydrogen employed, as hereinafter discussed. Forma-
tion of ethanol or other ethyl derivatives, however, is not noted '~
to occur to a significant extent, though these may be formed in
trace amounts. '
The mechanism of the reaction or reactions occurring is '' '''
not known. It is unlikely, however, that the desired ethylidene
diacetate is primarily formed by reaction '(l'.e., reduction) of
acetic anhydride with hydrogen present in the system, a reaction
disclosed by Fenton in U.S. Patent No. 3,579,566, because of the
behaviour o the reaction system of this invention in the presence
of especially preferred catalyst systems. According to recognized
reaction mechanism postulates with such preferred catalyst systems
~see Khan and Martell, "Homogeneous Ca'talysis o'f'Me'tal Comp'l'ex'es/"
Vol. I, Academic Press, New York (1974) at pages 49 and 315), the ~-
~C~6~8~S
formation of organo-metallic complexes of such catalysts with acid
anhydrides would be expected to be far less favored than would the
formation of such complexes with suspected reaction intermediates
such as acyl halides. The ready formation of such complexes with
acyl halides leads to facile reduction of the acyl halide in com-
parison to the acid anhydrides which would tend to preclude involve-
ment of anhydride reduction as a significant factor in the observed
ethylidene diacetate formation reaction. ;~
It will be further noted that the acetic acid co-product
of the overall carbonylation reaction is readily recovered as~ for
example, by distillation techniques, and can be purified for use
as such and/or can be reacted with methanol to produce the methyl
acetate reactant. Purification of the co-product acetic acid
obtained in this process is particularly facile since, because the
reaction medium is anhydrous, water removal is not required to
achieve concentrations approaching glacial. When the acetic acid
is recycled for use in preparing additional methyl acetate, the
over-all effect can, ln practice, result in a no co-product
ethylidene diacetate production process.
Further, since methanol itself can be readily converted to
dimethyl ether and/or to methyl acetate by known techniques, the
process of this invention provides a facile technique for the con-
version of methanol to ethylidene diacetate. And since methanol
need not be obtained from petroleum-based materials, the advantages
of this process over currently prevailing techniques for production
of any one or more of acetic anhydride, acetaldehyde, vinyl acetate,
and acetic acid becomes readily apparent.
The reactions described by the foregoing equations are
advantageously carried out in the presence of appropriate catalyst
systems. Those based upon the Group VIII noble metal catalysts,
particularly ones based upon palladium~ iridium, and rhodium, most
--6--
.. .- .
~065~3S
preferably palladium and/or rhodium, are especially advantageous.
The efficacy o~ these preferred noble metal catalyst systems is
enhanced, particularly with respect to the reaction rate and con-
centration of the desired products by the concurrent use of
organic promoters capable of forming a coordination compound with
the Group VIII noble metal catalyst. Suitable organic promoters
are organic non-hydrocarbon materials containing within their
molecular structure one or more electron rich atoms possessing
one or more pairs of electrons available for formation of co-
ordinate bonds with the noble metal catalyst. Most such organicpromoters can be characterized as Lewis bases for the particular
anhydrous reaction system involved. Enhancement of catalyst per-
formance is also obtained by the use of inorganic (primarily
metallic) promoters in lieu of or in addition to the organic pro- ; -
moters. Suitable metallic promoters include elements and/or
compounds of elements having atomic weights greater than 5 of
Groups IA, IIA, IIIA, IVB, VIB, the non-noble metals of Group VIII,
and the metals of the lanthanide and actinide groups of the
Periodic Table as set forth in the "Handbook of Chemistry and
Physics," 42nd Ed., Chemical Rubber Publishing Co., Cleveland,
Ohio (1960) at pages 448-449. Preferred inorganic promoters
include the metals of Groups VIB and the non-noble metals of Group
VIII, especially chromium, iron, cobalt, and nickel and most pre-
ferably chromium.
Similar catalyst systems are also disclosed for carbonyla-
tion reactions in systems wherein hydrogen (though possibly
present in but trace amounts) is not a significant reactant in the
commonly assigned application oE Nabil Rizkalla entitled "Process
for Preparing Carboxylic Acid Anhydrides" Serial No. 246,465.
-
, ....... ~ .. . ~ . ... . . .
C~6~8~
The surprising nature of this invention is further illu-
strated by comparing the carbonylations herein described with
those disclosed in Schultz, U.S. Patent No. 3,689,533. In the
Schultz patent catalysts similar to those preerred for use herein
are employed, but in water-containing reaction systems; yet
ethylidene diacetate is not taught as produced despite the employ-
ment of very substantial amounts of hydrogen in conjunction with
carbon monoxide in the carbonylation reaction (note especially
Example 10 of this reference). It is fundamentally surprising
that the conjoint use of a substantially anhydrous reaction system
and hydrogen should so profoundly influence the course of the
reaction so as to permit the obtaining of a product never hereto-
fore suggested as obtainable by carbonylation techniques.
Detailed Description of the Invention
As indicated, this invention provides for the preparation
of ethylidene diacetate by the interaction of carbon monoxide and
hydrogen with at least one member of the group consisting of di~
methyl ether and methyl acetate. This reaction takes place in the
vapor or liquid phase, with liquid phase reaction being preferred.
When using dimethyl ether as the organic raw material
(in addition, of course, to carbon monoxide and hydrogen), it is
believed (but not confirmed) that the initial step involved is the
carbonylation of the ether to produce methyl acetate. Thus,
although dimethyl ether can readily be employed as a raw material
for use in the process of this invention, the use of methyl
acetate (alone or in admixture with dimethyl ether) is particularly
preferred.
When dimethyl ether is employed as the starting material
for the process of this inven-tion, the reaction can be carried out
in one or more reaction zones. Thus, in this embodiment, a pre-
ferred procedure would involve the use of two reaction zones, in
~C~6~385
the first of which dimethyl ether would be converted by carbonyla-
tion to methyl acetate, with the second reaction zone being devoted
to the conduct of the ethylidene diacetate-forming reaction. In
this fashion differing reaction conditions can be employed for (a) ;
the conversion of dimethyl ether to methyl acetate and (b) the
conversion of methyl acetate to ethylidene diacetate so that each
o the two reaction zones may be maintained under optimum condi-
tions for the reactions conducted therein.
However, the use of separate reaction zones is not neces-
sary because the conversion of dimethyl ether to methyl acetate
can be carried out concurrently with and in the same reaction zone
as that in which the ethylidene diacetate is formed. ;
Aside from the dimethyl ether and/or methyl acetate
reactants, necessary reactants for the production of the ethyli-
dene product are carbon monoxide and hydrogen. These can be intro-
duced to the reaction zone (or zones) either together or separately.
In vapor phase operation, it is, of course, also necessary to
introduce the source of halide together with the reactants, again
either together with or separately from the reactants.
It will be noted that while hydrogen is a necessary co-
reactant with carbon monoxide for the production of ethylidene di-
acetate, it is not a necessary co-reactant for the conversion of
dimethyl ether to methyl acetate. Assuming for convenience that
carbon monoxide and hydrogen are separately introduced to the
reaction zone wherein ethylidene diacetate is produced, each is
preferably employed in substantially pure form, as available com-
mercially. In each case, however, inert diluents such as carbon
. . .
dioxide, nitrogen, methane, and/or inert gases (e g., helium, argon,
neon, etc.) can be present if desired. The presence of inert
diluents of these types does not affect the desired carbonylation
reactions, but their presence makes it necessary to increase the
~6~85
total pressure in order to maintain the desired carbon monoxide
and hydrogen partial pressures.
All reactants (i.e., carbon monoxide, hydrogen, as well
as the methyl acetate and/or dimethyl ether) should be substan-
tially free from water since, in this fashion, the maintenance of
a substantially anhydrous condition within the reaction zone is ~ -~
facilitated. The presence of minor amounts of water, however,
such as may be found in these commercially available reactants, ~ -
is permissible. Normally, however, the presence of more than 5
10 mole ~ of water in any one or more of the reactants should be ;
avoided, the presence of less than 3 mole ~ of water is desired,
and the presence of less than 1.0 mole % of water is preferred.
More important, however, than the amount of water in feed or re-
cycle streams introduced to the reaction zone is the concentration
of free water plus alcoholic hydroxyl groups (which react in situ
to form water) present within the reaction zone. In practice, the
molar ratio of (a) water plus the molar equivalents of alcoholic
hydroxyl groups to (b) the number of moles of dimethyl ether and/or
methyl acetate within the reaction zone is the most convenient
method for defining this concentration. On this basis, this ratio
preferably should not exceed 0.1:1. Still lower values for this
ratio are advantageous, with optimal results being obtained with
values for this ratio ranging from about zero to about 0.05:1. In
vapor phase operation, control of this ratio is readily accomplished
by appropriate adjustment of the water and/or free alcohol (e.g.,
methanol) content of all streams introduced to the reaction zone
in relation to the quantity of ether and/or ester reactant intro-
duced thereto. In the preferred liquid phase operation, control
of this ratio is readily accomplished by maintaining the liquid
phase reaction medium with the reaction zone in a substantially
anhydrous state.
--10--
65~3~5
The presence of the conventional organic impurities ~ound :~
in commercial grades of dimethyl ether and/or methyl acetate, how- :
ever, pose no problem to the practice of this invention. ~.
As hereinabove indicated, preferred practice calls for .
conduct of the instant reaction in the liquid phase in the ~
presence of a substantially anhydrous liquid phase reaction medium. ;..:. .
Since water is not a product of the reactionl maintenance of sub-
stantially anhydrous conditions within the liquid phase reaction . :
medium is simply accomplished by insuring adequate dryness and
freedom from alcoholic hydroxyl groups (i.eO~ free alcohol) of the
necessary reactants and/or recycle streams (hereinafter discussed)
introduced to th reaction zone. The liquid phase reaction medium
thus contains reactants (carbon monoxide, hydrogen, dimethyl ether,
and/or methyl acetate), reaction products (ethylidene diacetate,
and acetic acid), as well as the halide necessary for the conduct
of the desired reaction, together with such co-products as may be
formed, including usually acetaldehyde and/or acetic anhydride.
To facilitate conduct of the reaction in the liquid phase,
solvents or diluents can be employed. The solvents or diluents ..
are preferably materials which are indigenous to the reaction sys-
tem such as, for example, excess dimethyl ether and methyl acetate
and/or methyl halide and/or acetyl halide (preferred halide sources),
and/or co-products commonly found in the reaction system, such as
acetic acid, acet~ldehyde, and/or acetic anhydride. Excess di-
methyl ether and/or methyl acetate are the preferred reaction
diluents, with acetic acid and/or acetic anhydride being the pre-
ferred alternates.
It is also practicable to employ organic solvents or
diluents which are inert .in the environment of the process. The
30 most suitable inert solvents or diluents are hydrocarbons free -
from olefinic unsaturation, typically the paraffinic, cycloparaffi-
nic, and aromatic hydrocarbons such as octane, benzene, toluene, .
, --11--
..
1~65885 ~ ~
the xylenes, c~clododecane, and the like. Other suitable solvents
include chloroform, carbon tetrachloride~ and acetone. When such
non-indigenous solvents or diluents are employed, they are pre-
ferably selected so that the solvent or diluent has a boiling
point sufficiently different from the components of the reaction -
mixture to facilitate the separation of the components of the
reaction mixture from the solvent or diluent.
Also as hereinbefore indicated, the reaction requires the
presence of a halide which, in the preferred liquid phase mode of
operation, would be a component of the liquid phase reaction med-
ium. Suitable halides are either bromide or iodide or mixtures
thereof, iodide being preferred. The halide would usually be
present largely in the form of methyl halide, acetyl halide, hydro-
gen halide, or mixtures of the foregoing species, and could be
introduced to the liquid phase reaction medium as such. However,
it is entirely sufficient, particularly in batch operation, to
charge materials to the liquid phase such that any one or more of
these materials ~i.e., methyl halide, acetyl halide, and/or hydro-
gen halide) are formed in situ. Materials which interact in situ
with the other components of the liquid phase reaction medium to
form methyl halide, acetyl halide, and/or hydrogen halide include
inorganic halide materials, e.g., salts such as the alkali metal
and alkaline earth metal salts, as well as elemental iodine and
bromine. In continuous operation, wherein reaction by-products
are separated (as for example, by distillation and/or extraction
techniques), and recycled to the reaction medium, organic halides
such as methyl halide and/or acetyl halide will be present as
components of the liquid phase reaction medium and can be recovered
and recycled to the reaction zone as such; thus, only a small
quantity of make-up halide need be supplied to compensate ~or such
losses in recovery as may be encountered.
.. . . . .
~65885
The amount of halide -that should be present in the liquid ~ ~
phase reaction medium is related to the amount of ether and/or ~ -
ester reactant introduced to the reaction zone, but otherwise can
vary over a wide range. Typically, 0.5 to 1,000 moles of ester
or ether per equivalent of halide, desirably 1 to 300 moles per
equivalent, and preferably 2 to 100 moles per equivalent are used.
In general, higher proportions of halide to ether and/or ester
reactant tend to increase reaction rate.
In typical practice the liquid phase reaction medium,
neglecting water and non-indigenous solvents or diluents employed,
would normally contain the following materials within the following
concentration ranges, expressed on a mole % basis unless otherwise `
indicated: `
Halide, wt. % (contained basis) 0.1-75
Acetaldehyde 0-40%
Acetic acid 1-75%
Acetic anhydride 0-80%
Ethylidene diacetate 1-60% ;
Dimethyl ether 0-50%
Methyl acetate 5-90%
When non-indigenous solvents are employed, they would
normally comprise from 5 wt. % to 95 wt. %, desirably from 10 wt.
to 90 wt. %, and preferably from 15 wt. % to 80 wt. % of the
liquid phase reaction medium.
A1SG not included in the foregoing tabulation are the
quantities of dissolved carbon monoxide and hydrogen necessarily
present within the liquid phase reaction medium in order to permit
the desired reaction or reactions to occur.
It will be noted that liquid phase reaction media within
the foregoing concentration ranges are readily processible in order
to recover ethylidene diacetate therefrom because of the wide
-13-
~06~ 5
difference in volatilities associated with these materials. Methyl
halides are yenerally highly volatile materials. These can thus
be readily separated by distillation and/or extraction techniques
for recovery and recycle to the reaction zone. Any acetic acid
and acetic anhydride present in the system can readily be recovered.
Ethylidene diacetate, however, is of substantially lesser volatil- ;
ity and can accordingly readily be recovered in whatever degree
of purity may be desired. Inert solvents or diluents, if present,
can readily be chosen from the standpoint of volatility character-
istics to facilitate their recovery and re-use.
As indicated, the process of this invention preferably ;
occurs in the presence of a liquid phase reaction medium confined
within a reaction zone. A single reaction zone or a plurality of
reaction zones in series or in parallel may be employed. The pro-
cess itself can be carried out in batch~ semi-continuous, or con-
tinuous manner. The reaction zone itself may comprise one or more
autoclaves or an elongated tubular zone or series of such zones.
Of course, reaction zone construction should be such that the
reaction zone can withstand reaction temperature and pressure and
~0 should be fabricated from materials inert during the conduct of
the reaction. Suitable inert materials for reaction zone con-
struction include tantalum, zirconium, various of the stainless
steels, the Hastelloys, and the like. The reaction zone is suit-
ably Eitted with internal and/or external heat-removal devices to
absorb the exothermic heat of reaction and facilitate maintenance
of proper temperature control during the course of the reaction.
Suitably, the reaction zone is configured to provide sufficient
agitation to insure adequate contact between the carbon monoxide
and hydrogen reactants and the ether-acetate reactants. Any con-
venient agitation means known to those skilled in the art may beused, including vibration, shaking, stirring, etc.~ as illustra-
-14-
5885
tive techniques. Normally the reactants would be introduced at
a point within the reaction zone below the level of the liquid
phase reaction medium maintained therewithin in order to facili-
tate agitation and adequate contact by gas-sparging techniques.
The process of this invention can be carried out over a
wide range of temperatures. Temperatures, for example from 20-
500C. are suitable, with temperatures of 80-350C. being desired,
and temperatures of 100-250C. being preferred. Temperatures
lower than those mentioned can be used but they tend to lead to -
reduced reaction rates. Higher temperatures than those mentioned
can be employed, but there is no particular advantage to such
practice.
Reaction time is not a significant parameter of the pro-
cess of this invention, depending to a large extent upon the
temperature employed as well as upon reactant concentrations.
Suitable reaction times (l.e., times sufficient for the ethylidene
diacetate-forming reaction to occur) for liquid phase embodiments
will normally be within the range of 0.05 to 20 hours. Reaction
time in a batch system is self-explanatory. In a continuous
system, the residence time is defined as the quotient obtained by
dividing the volume of the liquid phase reaction medium within
the reaction zone by the rate (in consistent volume units per hour)
at which the dimethyl ether and/or methyl acetate (both fresh feed
and any recycled material) is introduced to the reaction zone.
For the preferred liquid phase embodiments, reaction total
pressure also is an unimportant process parameter so long as it is
sufficient to maintain the liquid phase reaction medium and the
appropriate carbon monoxide and hydrogen partial pressures. Suit-
able carbon monoxide and hydrogen partial pressures are each pre-
ferably within the range of 5-5,000 psi, most preferably within
the range of 25-3,000 psi. Broader partial pressure ranges,
-15-
: - : ' ' ,
..
~)658135
however, can be employed, with ranges from 0.1 to 15~000 psi being ~
applicable. While yet higher partial pressures can be employed, ~ -
there is little advantage to their use and a substantial economic ;
penalty would be incurred as a result of building equipment
capable of withstanding such higher pressures.
The stoichiometry of the chemical equations presented
earlier in this specification suggests that the reaction resulting
in the formation of ethylidene diacetate would require a molar
ratio of carbon monoxide to hydrogen varying from 2:1 to 4:1,
depending upon whether dimethyl ether or methyl acetate (or mix-
tures thereof) was employed. It has, however, been found that
much broader molar ratios of carbon monoxide to hydrogen, broadly
within the range of 1:100 to 100:1, desirably within the range of
50:1 to 1:50, and preferahly within the range of 10:1 to 1:10 can
be employed. Best results are obtained with carbon monoxide-
hydrogen mixtures which approach the stoichiometric ratios of
carbon monoxide to hydrogen. Molar ratios of carbon monoxide to
hydrogen within the range of 0.5:1 to 5:1 are thus an especially
preferred regime of operation.
The molar ratios of carbon monoxide to hydrogen also
affects the nature of the co-products obtained. The foregoing
equations indicate that acetic acid is the co-product formed.
Other co-products can however be made, especially acetic anhydride
and acetaldehyde. For example, other conditions remaining con-
stant in a liquid phase system, increasing the molar ratio of
carbon monoxide to hydrogen increases the molar ratio of acetic
anhydride to acetic acid produced. Conversely, reducing the molar
ratio of carbon monoxide to hydrogen increases the molar ratio of
acetaldehyde to acetic acid produced. Thus, the process of this
invention provides a considerable degree of flexibility in the
distribution of co-products obtainable.
-16-
, ~
, . .
~gl65~S
For liquid phase operation, the molar ratios of carbon
monoxide plus hydrogen to dimethyl ether and/or methyl acetate
employed are dictated by the partial pressure criteria set forth
above, since partial pressure and liquid phase concentration of
these normally gaseous reactants are directly interrelated.
Once the reaction has been carried out, the reaction
effluent is withdrawn from the reaction zone and introduced into ;
a distillation zone which can comprise one or a series of distilla-
tion columns. In these columns, ethylidene diacetate and co-
product acetic acid (and/or acetic anhydride and/or acetaldehyde)
are recovered and unconverted or partially converted materials and
halogen-containing components of the reaction medium are recovered
for recycle to the reaction zone. The catalyst can also be readily
recovered for recycle to the reaction zone if desired.
As hereinbefore indicated, the ethylidene diacetate-
forming reaction to which this invention is directed is advan-
tageously carried out in the presence of a carbonylation catalyst. `
In preferred practice, this carbonylation catalyst employed is
based upon use of one or more Group VIII noble metal catalysts,
i.e., one or more of ruthenium, rhodium, palladium, osmium,
iridium, platinum. Those based upon palladium, iridium, and
rhodium are preferred, while rhodium and/or palladium appear to be
especially advantageous and are particularly preferred.
The carbonylation catalyst, suitably a Group VIII noble
metal, can be employed in any convenient Eorm, viz., in the zero
valent state or in any higher valent form. For example, the -
catalyst to be added can be the metal itself, in finely divided
form, or it can be added as a carbonate, oxide, hydroxide, nitrate,
bromide, iodide, chloride, lower alkoxide (i.`e., Cl-C5, such as
the methoxide or ethoxide), phenoxide, or metal carboxylate where-
in the carboxylate ion is derived from an alkanoic acid of 1 to 20
-17-
.. : . ~ . .
. ~
~65~385
carbon atoms. Similarly, complexes of the metals can be employed,
for example, the metal carbonyls, such as the iridium and rhodium
carbonyls, or as othex complexes such as the carbonyl halides,
e.g., iridium tri-carbonyl chloride LIr(CO)3Cl]2 or as the acetyl-
acetonates, e.g., rhodium acetylacetonate, Rh(C5H7O2)3. Pre-
formed ligand-like complexes can also be employed, such as dichloro
bis-(triphenylphosphine) palladium, dichloro bis-(triphenylphos-
phine) rhodium, and trichloro tris-pyridene rhodium. Using
rhodium as illustrative of the preferred noble metal carbonylation
catalysts, illustrative forms in which the noble metal carbonyla-
tion catalyst can be added to the system include, aside from those
already specifically listed, rhodium oxide (Rh2O3), tetrarhodium
dodecacarbonyl, dirhodium octacarbonyl, hexarhodium hexadeca-
carbonyl (RH6(CO)16), rhodium (II) formate, rhodium (II) acetate,
rhodium (II) propionate, rhodium (II) butyrate, rhodium (II)
valerate, rhodium (III) naphthenate, rhodium dicarbonyl acetyl-
acetonate, rhodium trihydroxide, indenylrhodium dicarbonyl,
rhodium dicarbonyl (l-phenylbutane~1,3-dione), tris(hexane~2,4-
dione) rhodium (III), tris(heptane-2,4-dione) rhodium (III), tris-
(1-phenylbutane-1,3-dione) rhodium (III), tris(3-methylpentane-
2,4-dione) rhodium (III), and tris(l-cyclohexylbutane-1,3-dione)
rhodium (III).
For liquid phase reaction systems, the noble me~al catalyst
can be employed in ~orms initially or eventually soluble in the
liquid phase reaction medium to provide a homogeneous catalyst
systemO Alternatively, insoluble (or only partially soluble)
~orms, providing a heterogeneous catalyst system, can be employed.
Amounts o~ carbonylation catalyst (calculated as contained noble
metal based upon the total quantity of liquid phase reaction
medium) of as little as about 1 x 10 4 wt. % (1 ppm) are effective,
although normally amounts of at least 10 ppm, desirably at least
-18-
' ' , ' ' ' : ': ,~ ' ' ,',
i885
25 ppm, and preferably at least 50 ppm would be employed. Upper
concentration limit on carbonylation catalyst quantity appears to -
be controlled more by economics than by any advantage in either
rate or selectivity that can be observed. These limits would
normally suggest that more than 50,000 ppm of contained noble
metal would not normally be employed. An optimum balancing of
reaction rate and economic criteria would normally suggest the use
of amounts of contained noble metal carbonylation catalyst based
upon the total weight of liquid phase reac~ion medium between
about 10 and about 50,000 ppm, desirably between about 100 and
25,000 ppm, and preferably between about 500 and 10,000 ppm.
The efficacy o~ these preferred noble metal catalyst
systems, as has been noted above, is enhanced, particularly with
respect to the reaction rate and coneentration of the desired
products, by the concurrent use of promoters. Effective promoters
can be inorganic or organic or can be mixtures (or compounds) of
both organic and inorganic species.
Suitable organic promoters are non-hydrocarbon materials
capable of forming a coordination compound with the Group VIII
noble metal catalyst, containing within their molecular structure
one or more pairs of electrons available for formation of co-
ordinate bonds with the noble metal eatalyst. Such promoters ean
be introdueed concurrently with the reaetants to the reaction zone
or ean be ineorporated together with the Group VIII noble metal by
formation of ligand eomplexes with the noble metal prior to intro-
duetion of the noble metal-ligand complex to the reaction zone.
When pre-formed ligand complexes are used, concurrent use of
promoters (either organic or inorganic) is not necessary, though
of course such ean be employed if desired.
:
--19--
~ '
..... . . . . . .
~ ~ . . . . ..
~L~65~3~35
Suitable or~anic promoters are org~no-phosphine, organo-
arsine, organo-stibine, organo-nitrogen, and organo-oxygen con-
taining compounds. Organo-phosphine and organo-nitrogen promoters
are preferred classes.
Suitable oxgen-containing compounds capable of ~unction-
ing as organic promoters in this system are those containing
functional groups such as the phenolic hydroxyl, carboxyl, car-
bonyloxy, carbonyl, and the like groups. Suitable organo-nitrogen
containing compounds are those containing amino, imino, and nitrilo
groups. Materials containing both oxygen and nitrogen atoms can
be used.
Illustrative oxygen-con-taining organic promoters, by way
of illustration ~ut not limitation, are glycolic acid, methoxy-
acetic acid, ethoxyacetic acid, diglycolic acid, thiodiglycolic
acid, benzoic acid, pyromellitic acid, toluic acid, tetrahydro-
furan, dioxane, tetrahydropyran, pyrocatechol, citric acid, 2-
methoxyethanol, 2-ethoxyethanol, 2-n-propoxyethanol, 2-n-butyl-
ethanol, 1,2,3-trihydroxybenzene, 1,2,~-trihydroxybenzene, 2,3-
dihydroxynaphthalene, cyclohexane-1,2-diol, 1,3-epoxypropane, 1,2-
dimethoxybenzene, 1,2-diethoxybenzene, 1,2-dimethoxyethane, 1,2-
diethoxyethane, l,2-di-n-propoxyethane, 1,2-di-n-butoxyethane,
pentane-2,4-dione, hexane-2,~-dione, heptane-3,5-dione, octane-
2,4-dione, 1-phenylbutane-1,3-dione, 3-methylpentane-2,~-dione;
the mono- and dialkyl ethers of propylene glycol, of diethylene
glycol, of dipropylene glycol; and the like.
Suitable nitrogen-containing organic promoters include,
by way of illustration, pyrrole, pyrrolidine, pyridine, piperidine,
; pyrimidine, the picolines, pyrazine (and their N-lower alkyl-
substituted derivatives, lower alkyl meaning Cl-C5 such as N-
methyl pyrrolidine), benzotriazole; N,N,N',N'-tetramethylethylene-
diamine, N,N,N',N'-tetraethylethylenediamine, N,N,N',N'-tetra-n-
-20-
.. . . ..
:, , , ~ ;
~06S~
propylethylenediamine, N,N,N',N'-tetramethylmethylenediamine, : -
N,N,N',N'-tetraethylmethylenediamine, N,N,N',NI-tetraisobutyl-
methylenediamine, piperazine, N-methylpiperazine, N-ethylpipera-
zine, 2-methyl-N-methylpiperazine 2,2'-dipyr.idyl, methyl-substi- .
tuted 2,2'-dipyridyl, ethyl-substituted 2,2'-dipyridyl, l,4- .
diazabicyclot2.2.2.1octane, methyl-substituted l,4-diazabicyclo-
12.2.21octane, purine, 2-aminopyridine, 2-~imethylamino)pyridine,
l,lO-phenanthroline, methyl-substituted l,lO-phenanthroline, 2- .
(dimethylamino)-6-methoxyquinoline, 7-chloro-l,lO-phenanthroline,
4-triethylsilyl-2,2'-dipyridyl/ 5-(thiapentyl)-l,lO-phenanthroline,
tri-n-butylamine, and the like.
Suitable organic promoters containing both oxygen and ~:
nitrogen atoms are ethanolamine, diethanolamine, isopropanolamine,
di-n-propanolamine, N,N-dimethylglycine, N~N-diethylglycine, l- :
methyl-2-pyrrolidinone, 4-methylmorpholine, N,N,N',N'-tetramethyl-
urea, iminodiacetic acid, N-methyliminodiacetic acid, N-methyldi-
ethanolamine, 2-hydroxypyridine, methyl-substituted 2-hydroxy-
pyridine, picolinic acid, methyl-substituted picolinic acid,
nitrilotriacetic acid, 2,5 dicarboxypiperazine, N-(2-hydroxyethyl)-
iminodiacetic acid, ethylenediaminetetraacetic acid, 2,~-dicarboxy- ~ .
pyridine, 8-hydroxyquinoline, 2-carboxyquinoline, cyclohexane-l,2-
diamine-N,N,N',N'-tetraacetic acid, the tetramethyl ester o~
ethylenediaminetetraacetic acid, and the like. .
Suitable stibines and arsines are exemplified by the
followiny illustrative materials: trimethyl arsine, triethyl .
arsine, triisopropyl stibine, ethyldiisopropyl stibine, tricyclo-
hexyl arsine, triphenyl stibine, tri(o-tolyl)stibine, phenyldiiso-
propyl arsine, phenyl diamyl stibine, diphenylethylarsine, tris-
(diethylaminomethyl) stibine, ethylene bis(diphenyl arsine),
hexamethylene bis(diisopropyl arsine) pentamethylene bis(diethyl-
stibine) etc.
-21 -
``" ~L~6~
Preferred organic promoters are the organo nitrogen or
organo phosphorus compounds wherein the nitrogen or phosphorus
atoms are, at least in part, trivalent. Many of these preferred
compounds may also contain oxygen atoms such as, for example, 1-
methyl-2-pyrrolidinone and N,N,N',N'-tetramethylurea. Especially
preferred are the tertiary amines of the formula:
Rl R3
N
R2 /
wherein Rl, R2, and R3 are the same or different and are alkyl,
cycloalkyl, or aryl radicals, each preferably having not more than
about 10 carbon atoms. Also especially preferred are the hetero-
cyclic amines of the pyridine type such as pyridine itself, the
picolines, quinoline, and methyl quinoline. The tertiary phos-
phines of the following formula:
R4 R6
5 /
R
wherein R4, R5, and R6 have the same meaning as Rl, R , and R3,
respectively, are also especially preferred. Exemplary of particu-
larly suitable phosphines include trimethyl phosphine, tri-t-
butyl phosphine, tri-n-butyl phosphine, tricyclohexyl phosphine,
and triphenyl phosphine.
The quantity of organic promoter employed is related to
the quantity of noble metal catalyst within the reaction zone.
Normally the quantity is such that at least 0.1, desirably at
least 0.2, and preferably at least 0.3 mole of promoter compound
per mole of noble metal is present in the reaction zone. Little ,~
advantage is observed, on the other hand, when large excesses of
organic promotex per mole of noble metal catalyst are employed.
Normally, therefore, operation with more than 500 moles of pro-
-22-
6588~
:.
moter per mole of noble metal catalyst in the reaction zone would
not be employed. Desirably less than 200 moles of promoter per
mole of noble metal, and preferably less than 100 moles of promoter
per mole of noble metal catalyst would be used. Particularly
advantageous results are obtained when the number of moles of
organic promoter per mole of noble metal catalyst within the re-
action zone is between 0.2 and 200 moles per moleJ and preferably
between 0.3 to 100 moles per mole.
The foregoing ratios of organic promoter to noble metal
of course assume that the promoter and noble metal are introduced
to the reaction zone as distinct species. When, as also indicated
to be practicable, pre-formed organic promoter-noble metal ligand
complexes are employed, the amount of promoter is, of course,
dictated by the stoichiometry of the complex. Additional promoter
can then be added to the reaction zone during the course of the
reaction, either periodically or continuously, to assist in main-
tenance of the stability of the cornplex, if desired.
An additional type of organically promoted noble metal
catalysts of utility as carbonylation catalysts for the process of
this invention are those in which the noble metal catalyst metal
is chemically bonded to a polymeric substrate which can be organic
or inorganic. Such metal-polymer complexes are clearly hetero-
geneous in the physical sense because insoluble; however, they ;
display chemical characteristics more nearly akin to homogeneous
than to heterogeneous catalysis. Such metal-polymer complexes and
procedures for their preparation are known; see Michalska~ Z.M.
and Webster, D.E. "Supported Homogeneous Catalysts," CHEMTECH,
Feb. 1975, pages 117-122 and references cited therein. Those
complexes particularly suitable for use in this invention comprise
noble metal bonded to a silica, polyvinyl chloride or cross-linked -
polystyrene-divinylbenzene substrate by phosphine, silyl, amine,
or sulfide linkages.
.. . . . . .
' '' : : : , ' ' ,', . ;.: : ,
~1658E~
Effective inorganic promoters include the elements (and
compounds of elements) having atomic weights greater than 5 of
Groups IA, IIA, IIIA, IVB, VIB, the non-noble metals of Group VIII,
and the metals of the lan-thanide and actinide groups of the
Periodic Table. Particularly preferred are the lower atomic
weight metals of each of these groups, e~g~, those having atomic
weights lower than 100, and especially preferred are the metals
of Groups VIB and the non-noble metals of Group VIII. In general
the most preferred elements are lithium, magnesium, calcium,
titanium, chromium, iron, cobalt, nickel, and aluminum. Most
preferred are lithium, chromium, cobalt, iron and nickel, especial-
ly chromium.
The inorganic promoters can be used in their elemental
form, ~ ~, as finely divided or powdered metals, or they can be
employed as compounds of various types, both organic and inorganic,
which are effective to introduce the element as the cation into
the reaction system under reaction conditions. Thus, typical
compounds of the promoter elements include oxides, hydroxides,
halides (preferably bromides and iodides), oxyhalides, hydrides,
carbonyls, alkoxides, nitrates, nitrites, phosphates, phosphites,
and the like. Especially preferred organic compounds are the salts
of organic aliphatic, cycloaliphatic, naphthenic and araliphatic
monocarboxylic acids, e.g., alkanoates such as the acetates,
butyrates, decano~tes, laurates, stearates, benzoates, and the ,
like. Other suitable compounds include the metal alkyls as well
as chelates, associate compounds and enol salts. Particularly
preferred are the elemental forms, compounds which are bromides
and iodides and organic acid salts, preferably acetates. Mixtures
of inorganic promoters can be used if desired, especially mixtures
of elements from different groups of the Periodic Table.
-24-
, . .
,
: . . ~','' '; ' ',''; .' :, : ' ~ ' :,
;58~3S
The quantity of inorganic promoter can vary widely, but
preferably it is used in an amount such that from 0.0001 mole to -
100 moles per mole of Group VIII noble metal catalyst, most pre-
ferably from 0.1 to 10 moles per mole of catalyst, are contained
within the reaction zone. `-~
Of course, it is also practicable, and sometimes advan-
tageous, to use both organic and inorganic promoters in conjunction
with the noble metal catalyst. Thus, for example (in conjunction
with the espeGially preferred palladium and rhodium noble metal
catalysts) systems which are only organic such as, for example,
the tertiary amines, heterocyclic nitrogen compounds of the pyri- `
dine type, or tertiary phosphines can be employed as the promoters.
Inorganic promoters, especially chromium, iron, nickel, or cobalt,
and most preferably chromium, can be used instead of the organic
types. However, the use of phosphine or amine promoters in con-
junction with chromium, iron, nickel, or cobalt, and most preEer-
ably with chromium, is practicable and is highly effective.
The following examples are presented to illustrate further
the above-described invention but are not intended as limiting the
scope thereof. Unless otherwise indicated, all parts and percents
in the following examples are on a weight basis. In these examples,
the term "liquid phase" means the liquid portion of the reaction
mixture other than dissolved catalyst components (including the
halide source) which may be present, and vther than any solvent
used.
Example_I
To a one gallon autoclave fitted with a turbine-type
agitator are charged 60 parts of methyl acetate, 1 part of rhodium
chloride txihydrate, 3 parts of 3-picoline, and 20 parts of methyl
iodide. The autoclave is then sealed and pressured to 500 psig
with carbon monoxide. At this point hydrogen is added to the auto-
-25-
'. :` . . ` ' `` : :
: . . .
~6S~385
clave, raising the pressure therewi-thin to 1,000 psig. The auto-
clave and its contents are then heated to 150C. and maintained
at this temperature for 3 hours, following which the autoclave is
allowed to cool, depressured, and the liquid phase therewithin
is analyzed by gas chromotographic (G.C.) techniques. The liquid
phase is found to contain 44 wt. % ethylidene diacetate, 6.5 wt. %
acetic anhydride, and 0.6 wt. % of acetaldehyde, together with a
substantial amount of acetic acid. The remainder of the liquid
phase is primarily unconverted components of the initial charge.
Example II
The procedure and equipment of Example I are employed
using as initial charge 60 parts of methyl acetate, 1.6 parts of
palladium acetate, 10 parts of triphenyl phosphine, and 20 parts
of methyl iodide. Carbon monoxide and hydrogen are added in the
same fashion and to the same pressure used in Example I. Reaction
is continued for 17 hours at 135C. Analysis of the reaction
products by G.C. techniques indicates the reaction effluent to
contain 34 wt. % ethylidene diacetate and 5.3 wt. % acetaldehyde, ;~
together with a substantial amount of acetic acid. The remainder ,;
of the liquid phase is primarily unconverted components of the
initial charge.
Example III
:
The procedure and equipment of Example I are employed
using as initial charge 60 parts methyl acetate~ 5 parts dichloro
bis-(triphenylphosphine)-palladium, 2 parts triphenylphosphine,
and 20 parts methyl iodide. Carbon monoxide and hydrogen are ;
added in the same fashion and to the same pressure used in Example
I. Reaction is continued for 17 hours at 135C. Analysis of the
reaction products by G.C. techniques indicates the reaction
effluent to contain 31 wt. % ethylidene diacetate and 9.6 wt. %
acetaldehyde, together with a substantial amount of acetic acid.
~ -26-
65~
The remainder of the liquid phase is primarily unconverted
components of the initial charge.
Example IV
The procedure and equipment of Example I are em-
ployed using as initial charge 60 parts methyl acetate, 1
part rhodium chloride trihydrate, 3 parts chromium carbonyl,
and 20 parts methyl iodide. Carbon monoxide and hydrogen
are added in the same fashion and to the same pressure used
in Example 1. Reaction is continued for 4 hours at 150C.
Analysis of the reaction products by G.C. techniques in-
dicates the reaction effluent to contain 13~wt. % ethylidene
diacetate, 0.6 wt. % acetaldehyde, and 17.8 wt. % acetic
anhydride, together with a substantial amount of acetic acid.
-26a- :~
0~5~
The remainder of the liquid phase is primarily unconverted com-
ponents of the initial char~e.
Example V
The procedure and equipment of Example I are employed
using as initial charge 60 parts methyl acetate, 1 part rhodium
chloride trihydrate, and 20 parts methyl iodide. Carbon monoxide
and hydrogen are added in the same fashion and to the same pres- ;~
sure used in Example I. Reaction is continued for 3 hours at
150C. G.C. analysis of the reaction effluent indicated no re-
action products to have been obtained~ Thus, this example illus-
trates the advantages accruing to the con~oint use of an organic
and/or inorganic promoter together with a noble metal catalyst,
as in the preceding examples.
Example VI
The procedure and equipment of Example I are employed
using as initial charge 60 parts methyl acetate, 2 parts dichloro ;
bis-(triphenylphosphine) rhodium, 3 parts triphenylphosphine, and
20 parts methyl iodide. Carbon monoxide and hydrogen are added
in the same fashion and to the same pressure used in Example I.
Reaction is continued for 3 hours at 150C. Analysis of the
reaction products by G.C. techniques indicates the reaction efflu-
ent to contain 13 wt. % ethylidene diacetate and 7.4 wt. ~ ;
acetaldehyde, together with a substantial amount of acetic acid.
The remainder of the liquid phase is primarily unconverted com-
ponents of the initial charge.
Example VII
The procedure and equipment of Example I are employed
using as initial charge 60 parts methyl acetate, 1 part palladium
chloride, 3 parts chromium carbonyl~ 3 parts of 3-picoline, and
20 parts of methyl iodide. Carbon monoxide and hydrogen are added
-27-
658~
in the same fashion and to the same pressure used in Example I~
Reaction is continued for 3.5 hours at 150C. Analysis of the
reaction products by G.C. techniques indicates the reaction
effluent to contain 2 wt. ~ ethylidene diacetate and 7 wt.
acetaldehyde, together with a substantial amount of acetic acid~
The remainder of the liquid phase is primarily unconverted com-
ponents of the initial charge. This experiment was repeated but
the reaction was continued for only 2 hours. G.C. analysis of the
liquid phase shows it to contain 10 wt. ~ ethylidene diacetate and
10 wt. % acetaldehyde with the remainder again being a substantial
amount of acetic acid and unconverted components of the initial
charge, no acetic anhydride being present.
Example VIII
: i
The procedure and equipment of Example I are employed
using as initial charge 60 parts methyl acetate, 1.2 parts pallad-
ium chloride, and 20 parts methyl iodide. Carbon monoxide and
hydrogen are added in the same fashion and to the same pressure
used in Example I. Reaction is continued for 17 hours at 135 C. ~-
G.C. analysis of the reaction effluent indicated no reaction
products to have been obtained. Thus, this example, like Example
V, illustrates the advantages accruing to the conjoint use of an
organic and/or inorganic promoter together with a noble metal
catalyst.
Exam~le IX
The procedure and equipment of Example I are employed
using as initial charge 60 parts methyl acetate, 2 parts trichloro
tris(pyridine)rhodium, and 20 parts methyl iodide. Carbon monoxide
and hydrogen are added in the same fashion and to the same pres-
sure used in Example I. Reaction is continued for 3 hours at
155 C. Analysis of the reaction products by G.C. techniques
indicates the reaction effluent to contain 25 wt. ~ ethylidene di-
-28-
s
acetate and 42 wt. ~ acetic anhydride together with a substantial
amount o~ acetic acid. The remainder of the liquid phase is
primarily unconverted components of the initial charge. No acet-
aldehyde is found.
Example X
The procedure and equipment of Example I are employed
using as initial charge 60 parts methyl acetate~ 1.3 parts pal- ;
ladium chloride, 6 parts tri-n-butyl phbsphine~ and 20 parts methyl
iodide. Carbon monoxide and hydrogen are added as in Example I ~,~
except that the pressures used are 300 and 600 psig, respectively.
Reaction is continued for 17 hours at 135C. Analysis of the
reaction products by G.C. techniques indicates the reaction efflu- ~-
ent to contain 12.4 wt. ~ ethylidene diacetate and 12 wt. ~ acet-
aldehyde, together with a substantial amount of acetic acid. The
remainder of the liquid phase is primarily unconverted components ~;
of the initial charge.
Example XI
.:. .. ''.
The procedure and equlpment of Example I are employed
using as initial charge 100 parts (mole basis) of methyl acetate, -
17 parts (mole basis) of methyl iodide, and 0.4 part (mole basis)
of a pre-formed rhodium pyridine ligand complex havin~ the formula
RhC13(pyridine)3. Carbon monoxide and hydrogen are added in the
same fashion and to the same pressures used in Example I. Reaction
is continued for 17 hours at 150C. Analysis of the reaction
products by G.C. techniques indicates the reaction effluent to
contain 13 mole ~ ethylidene diacetate, no acetaldehyde, and no
acetic anhydride. The effluent contains a substantial amount of
ace-tic acid, with the remainder of the liquid phase being primarily
unconverted components of the initial charge. This example illus-
30 trates the employment of a pre-formed noble metal ligand complex ~ -
in lieu of employment of an organic promoter added as such.
, .
6~8~
Example XII
The procedure and equipment of Example I are employed
using as initial charge 60 parts of methyl acetate, 1.6 parts of
palladium diacetate, 10 parts of triphenyl phosphine, and 20 parts
of methyl bromide Carbon monoxide and hydro~en are added as in
Example I except that the pressures used are 300 and 600 psig,
respectively. Reaction is continued for 17 hours at 135C.
Analysis of the reaction products by G.Cv techniques indicates the
reaction effluent to contain 14 wt. % ethylidene diacetate, 0.4
wto % acetaldehyde, and 2 wt. % acetic anhydride, together with a
substantial amount of acetic acid. The remainder of the liquid
phase is primarily unconverted components of the initial charge.
Example XIII
The procedure and equipment of Example I are employed
using as initial charge 60 parts of methyl acetate, 1.6 parts oE
palladium diacetate, 2 parts of imidazole, and 20 parts of methyl
iodide. Carbon monoxide and hydrogen are added as in Example I
except that the pressures used are 300 and 600 psig, respectively.
Reaction is continued for 17 hours at 135C. Analysis of the
reaction products by G.C. techniques indicates the reaction efflu-
ent to contain 3.4 wt. % ethylidene diacetate and 6.1 wt~ % acet-
aldehyde, together with a substantial amount of acetic acid. The
remainder o the liquid phase is primarily unconverted components
of the initial charge.
Example XIV
_ _
The procedure and equipment of Example I are employed
using as initial charge 60 parts of methyl acetate, 1.6 parts of
palladium diacetate, 3 parts of chromium carbonyl, 15 parts of
N,N-dimethyl acetamide, and 20 parts of methyl iodide. Carbon
monoxide and hydrogen are added in the same fashion and to the same
-30-
~58~S
pressure used in Example I. Reaction is continued for 17 hburs
at 135C. Analysis of the reaction products by G.C. techniques
indicates the reaction effluent to contain 27 wt. ~ ethylidene
diacetate and 3.3 wt. % acetaldehyde, together with a substantial
amount of acetic acid. The remainder of the liquid phase is pri-
marily unconverted components of the initial charge.
Example XV
The procedure and equipment of Example I are employed
using as initial charge 60 parts o~ methyl acetate, 1.6 parts of ~ -
palladium diacetate, 10 parts of hexamethylphosphoramide, and 20
parts of methyl iodide. Carbon monoxide and hydrogen are added in
the same fashion and to the same pressure used in Example I.
Reaction is continued for 17 hours at 135C. Analysis of the re~
action products by G.C. techniques indicates the reaction effluent
to contain 21.7 wt. % ethylidene diacetate and 1.6 wt. ~ acet-
aldehyde, together with a substantial amount of acetic acid. The
remainder of the liquid phase is primarily unconverted components
of the initial charge. The hexamethylphosphoramide employed in
this example is illustrative of a nitrogen-type promoter rather
than of a phosphorous-type promoter because, in this compound, the
phosphorous atom is in the ~6 valence state and does not possess
a pair of electrons available for formation of a coordinate bond
with the noble metal catalyst.
Example XVI
- .
The procedure and equipment of Example I are employed
usin~ as initial charge 60 parts of methyl acetate, 1.6 parts of
palladium diacetate, 10 parts of N,N-dicyclohexylmethylamine, and
20 parts of methyl iodide. Carbon monoxide and hydrogen are added
in the same fashion and to the same pressure used in Example I.
Reaction is continued for 17 hours at 135C. Analysis of the re-
action products by G.C. techniques indicates the reaction effluent
-31-
65~3~5
to contain 14.6 wt. % ethylidene diacetate and 4.9 wt. % acetal-
dehyde, together with a substan-tial amount of acetic acid. The
remainder of the liquid phase is primarily unconverted components
of the initial charge.
Example XVII
.
The procedure and equipment of Example I are employed
using as initial charge 30 parts of dimethyl ether, 43 parts of
methyl acetate, 2 parts of palladium dichloride, 10 parts of tri-
phenyl phosphine, and 31 parts of methyl iodide. Carbon monoxide
and hydrogen are added as in Example I except that the pressures
used are 300 psig and 300 psig, respectively. Reaction is con-
tinued for 17 hours at 150C. Analysis of the reaction products
by G.C. techniques indicates the reaction effluent to contain 2
wt. % ethylidene diacetate and 44 wt~ % methyl acetate, together
with a substantial amount of acetic acid. The remainder of the
liquid phase consists primarily of unconverted components of the
initial charge.
Example XVIII
The procedure and equipment of Example I are employed
using as initial charge 60 parts of methyl acetate, 3 parts of
chromium carbonyl, 3 parts of rhodium trichloride trihydrate, and
26 parts of N-methyl pyridinium iodide. Carbon monoxide and hydro-
gen are added as in Example I except that the pressures used are
300 psig and 300 psig, respectively. Reaction is continued for
17 hours at 150C. Analysis of the reaction products by G.C.
techniques indicates the reaction effluent to contain 41.2 wt. %
ethylidene diacetate and 19 wt. % acetic anhydride, together with
a substantial amount of acetic acid. The remainder of the liquid
phase consists primarily of unconverted components of the initial
charge.
-32-
. . .
Example XIX
The procedure and equipment of Example I are employed
using as initial charge 60 parts of methyl acetate, 3 parts of
rhodium chloride trihydrate, and 20.5 parts of chromium iodide
(CrI3). Carbon monoxide and hydrogen are added as in Example I
except that the pressures used are 300 psig and 300 psig, re~
spectively. Reaction is continued for 17 hours at 150C. Analysis
of the reaction products by G.C. techniques indicates the reaction ~
e~fluent to contain 5.2 wt. % ethylidene diacetate and 10 wt. % -
10 acetic anhydride, together with a substantial amount of acetic ;
acid. The remainder of the liquid phase consists primarily of
unconverted components of the initial charge. -~
Examples XVIII and X~X illustrate the flexibility of this
process in relation to halide source since in neither example were
any methyl halide, acetyl halide, or hydrogen halide charged.
Example XVIII illustrates that organic halogen containing compounds
are suitable halide sources/ while Example XIX illustrates the use
of inorganic materials as halide sources.
Example XX
The procedure and equipment of Example I are employed `
using as initial charge 100 parts (mole basis) of methyl acetate, ;
17 parts (mole basis) of methyl iodide, 0.9 part (mole basis) of
palladium acetate (Pd(C2H5O2)2), and ~ parts (mole basis) of
benzotriazole. Carbon monoxide and hydrogen are added as in
Example I except that the pressures used are 300 psig and 300 psig,
respectively. Reaction is continued for 16 hours at 152C.
Analysis of the reaction products by G.C. techniques indicates the
reaction effluent to contain 20 wt. % ethylidene diacetate, 2 wt.%
acetic anhydride, 3 wt. % acetaldehyde, together with a substantial
amount o~ acetic acid. The remainder of the liquid phase consists ~-
primarily of unconverted components of the initial charge.
-33-
` 16~65~85
That portion of the effluent obtained in this example
which corresponds to the ethylidene diacetate adsorption peak
during the gas chromatographic analysis is, upon desorption,
passed through an ice-water trap in order to condense and recover
the ethylidene diacetate. The ethylidene diacetate so obtained
is analyzed by in~ra-red spectographic techniques and found to
have an infra-red spectrum identical with that of a commercially-
obtained sample of pure e~hylidene diacetate, thus confirming the
identity of the product and the validity of the gas chromatographic
techniques used for analysis in this and in the other examples
presented herein.
Example XXI
.
Methyl acetate (lO0 parts), methyl iodide (36.6 parts),
palladium acetate (3.5 parts), triphenyl phosphine (8 parts) and
chromium carbonyl (24 parts) are charged into a glass lined pres-
sure vessel which is pressured to 600 psig at room temperature
with carbon monoxide and hydrogen (95:5 ratio) and the vessel is
then closed and heated with stirring at 150C for 6 hours. Car-
bon monoxide and hydrogen mixture (95:5 ratio) is continuously
supplied to maintain a continuous total pressure in the vessel of
lO00 psig. After the 6 hours reaction time, G.C. analysis of the
liquid phase shows it to contain 14.2 wt. % ethylidene diacetate,
l9.1 wt. % methyl acetate, 59.8 wt. % acetic anhydrider and 6.9
wt. ~ acetic acid.
Example XXII
Methyl acetate (lO0 parts), methyl iodide (27 parts),
palladium acetate (2.6 parts), triphenyl phosphine (6 parts), and
chromium carbonyl (17.9 parts) are charged into a glass lined
pressure vessel which is pressured -to 600 psig at room temperature
with carbon monoxide and hydrogen (97.5:2.5 ratio) and the vessel
-34-
.
.
~65~
is then closed and heated with stirring at 150C for 6 hours.
Carbon monoxide and hydrogen mixture (97.5:2.5 ratio) is continu-
ously supplied to maintain a continuous -total pressure in the ~ `
vessel of 1000 psigO After the 6 hours reaction time, G.C. analy~
sis of the liquid phase shows it to contain 7.1 wt. % ethylidene
diacetate, 24.9 wt. % methyl acetate, 63.8 wt. % acetic anhydride,
and 4.2 wt. % acetic acid.
Example XXIII
. _ .
Methyl acetate (100 parts), methyl iodide (12.5 parts),
chromium carbonyl (18 parts), triphenyl phosphine (5.5 parts) and
palladium acetate (2.3 parts) are charged into a glass-lined
pressure reactor with 75U psig of a gas mixture composed of 97.3%
carbon monoxide and 2.7% hydrogen. The vessel is stirred for 14
hours at 150C. G.C. analysis of the liquid phase shows it to
contain 10% ethylidene diacetate, 18~ methyl acetate, 68% acetic ~`
anhydride and 4% acetic acid.
Example XXIV
Methyl acetate (100 parts), methyl iodide (12.5 parts),
chromium carbonyl (18 parts), triphenyl phosphine (5.5 parts) and
palladium acetate (2.3 parts) are charged into a glass-lined pres-
sure reactor with 750 psig of a gas mixture composed o~ 98.7
carbon monoxide and 1.3% hydrogen. The vessel is stirred for 14
hours at 150C. G.C. analysis o~ the liquid phase shows it to
contain 7~ ethylidene diacetate, 15% methyl acetate, 75% acetic
anhydride, and 3% acetlc acid.
Example XXV
__
Methyl acetate (100 parts), methyl iodide (12.5 parts),
chromium carbonyl (18 parts), triphenyl phosphine (5.5 parts) and
palladium acetate (2.3 parts) are charged into a glass-lined pres
sure reactor with 750 psig of a gas mixture composed of 93.3%
-35-
~65~3~5
carbon monoxide and 6.7% hydrogen. The ve~sel is stirred for 3
hours at 150C~ G.C. analysis of the liquid phase shows it to
contain 21% ethylidene diacetate, 38% methyl acetate, 29% acetic
anhydride, and 12% acetic acid.
Example XXVI
Methyl acetate ~100 parts), methyl iodide (14 parts),
palladium acetate (2.7 parts), triphenyl phosphine (6.2 parts) and
chromium carbonyl (20.6 parts) are charged into a Hastelloy-C
pressure vessel which is pressured to 600 psig at room temperature
with carbon monoxide and hydrogen (3:1 ratio) and the vessel is
then closed and heated with stirring at 150C for 9 hours. A car-
bon monoxide and hydrogen mixture is continuously supplied to
maintain a continuous total pressure in the vessel of 900 psig and
in amounts sufficient to keep the carbon monoxide to hydrogen ratio
in the reaction at the 3:1 ratio. After the 9 hburs reaction time,
G.C. analysis of the liquid phase shows it to contain 42 wt. %
ethylidene diacetate, 16 wt. % methyl acetate, 1 wt. ~ acetalde-
hyde, 23 wt. % acetic anhydride, and 18 wt. % acetic acid.
Example XXVII
Methyl acetate (100 parts), methyl iodide (18.8 parts),
acetic anhydride (34 parts), palladium acetate (3.6 parts), tri-
phenyl phosphine (8 parts) and chromium triiodide (55 parts) are
charged into a Hastelloy-C pressure vessel which is pressured to
600 psig at room temperature with carbon monoxide and hydrogen
(2:1 ratio), and the vessel is then closed and heated with stirring
at 160C for 2-1/2 hours. A carbon monoxide and hydrogen mixture
(2:1 ratio) is continuously supplied to maintain a continuous total
pressure in the vessel of 900 psig. After the 2-1/2 hours re-
action time, G.C. analysis of the liquid phase shows it to contain
30 30 wt. % ethylidene diacetate, 33 wt. % methyl acetate, 0.3 wt. %
acetaldehyde, 20 wt. % acetic anhydride, and 16.7 wt. ~ acetic acid.
-36-
.
5~3~5
Example XXVIII .
.:
Methyl acetate (100 parts), methyl iodide (65 parts), . :
palladium acetate (5~2 parts), triphenyl phosphine (7.9 parts) r ;~
chromium carbonyl (9.5 parts) and ethylene glycol diacetate as
solvent (130 parts) are charged into a Hastelloy-C pressure vessel
which is pressured to 600 psig at room temperature with carbon
monoxide and hydrogen (1:1 ratio). The vessel is then closed and
heated with stirring at 150C for 10 hours. Carbon monoxide and
hydrogen are continuously supplied to maintain a total pressure
in the vessel of B50 psig and a ratio of carbon monoxide and
hydrogen in the vessel of 1:1. After the 10 hours reaction time,
G.C. analysis of the liquid phase shows it to contain 48.8 wt. %
ethylidene diacetate, 0.6 wt. ~ acetaldehyde, 13 wt. % methyl
acetate, 11.6 wt. ~ acetic anhydride, and 26 wt. % acetic acid.
Example XXIX
, : , .
Methyl acetate (100 parts~, methyl iodide (34 parts), tri- :; :
phenyl phosphine, (17 parts) and palladium acetate (1.7 parts) are . ..
charged into a glass-lined pressure reactor with 1000 psig o~ a
gas mixture composed of 70~ carbon monoxide and 30~ hydrogen. The ;~
~0 vessel is stirred for 6 hours at 150C. G.C. analysis of the
liquid phase shows it to contain 33% ethylidene diacetate, 43%
methyl acetate, 19~ acetic acid, and 5~ acetaldehyde.
It will be understood that modifications and variations .
in the details described above may be effected by those skilled in . .
the art without departing from the spirit of this invention or .: :
from its scope as defined in the appended claims. Accordingly, it ~
is intended that all matter contained in the foregoing description :
shall be interpreted as illustrative only and not in a limiting .-:
sense. . ~ .
..
., .. . . .. :. .
