Note: Descriptions are shown in the official language in which they were submitted.
33~
HOE 81/H 044
The invention relates to a process for making acetic
anhydride and/or acetic acid and/or ethylidene diacetate by
reacting me~hyl acatate and/or dimethylether with carbon mon-
oxide or mixtures of carbon monoxide and hydrogen at tempe-
ratures of 50 to }00C, under reaction pressure of 1 to 500
bars in the presence of a catalyst system as disclosed9 e.g
in DE~OS 24 50 965; 28 36 084; 29 39 8~9 or 29 41 232.
The most rslevant component in such catalyst systam is
selected from noble metals belo~ging to group ~IIIl ol the
Periodic System, preferably rhodium, palladium~ iridium or
ruthenium, or their compounds
We have now unexpectedly ~.ound that rhenium can be sub-
stituted ~or these very ex~e~sive noble metals.
The process of this lnvention comprises ~ors ~articu-
larly: using, as the catal~st system, rhenium or l~s com-
pounds; an org~ohalogen compound,halogen or 'nydrogen halide;
~urther carbonyl-yielding common metals or their compounds, iL
desired; a tertiary or quaternary orgarlic nitrogen, phosphorus,
arsenic or antimon7 compound,if desired; and alkali met~l ace-
tate or alkali metal. compounds which undergo conversion toalkali metal acetate under the reaction conditions, i~ desired.
The further carbonyl-yislding common metals comprise more
particularly Cr, Mo, W9 Fe, Co or Ni.
Further preferred and optional features of the invention
provide:
a) for the catalyst system to be used in combination with
orga~ic nitrogen or phosphorus compounds quaternized
wlth methyl halide or hydrogen halide;
b) for methyl acetate or dimethyl ther/rhenium(-compound)/
halogen(-compound)/nitrogen, phosphorus, arsenic or an-
timony compound/alkali metal compound to be used in the
molar ratio of 1 : (0.0001 - 0.1) : (0.01 ~ (0 - 1) :
(0 - 0.1).
~henium compounds useful in the process o~ this invention
are, ~or example 9 rheniu~ chloride, rhenium oxychlorid0 or ~i-
rheniumdecacarbonyl~
The in~entio~ provides ~or the halogen to be used in ele-
mentary ~orm as chlori~e, bromine, iodine or in the ~orm of a
halogen compound, pre~erably me~hyl chloride, methyl bromide,
~ethyl iodide, HCl, H3r, HI It is also possible however to
se other alkyl halides and acyl halides inasmuch as the ~eed
materials are not very critical.
The tertiary or quaternary organic nitrogen, phosphorus,
arsenio or antimony compol~ds which may optionall~ be used
~i~e complexes with rhenium. The useful tertiary organonitro-
~en or organophosphorus compounds comprise amines, phosphines
or aminophosphines, pre~erably trialkylamines, N,N-dialkyl-
anil~ne, pyridine, pyrrolidone, trialkyl or triarylphosphines,
especially N-methylimida20le, 3-picoline, 2,4-lutidine, 3,4-lu-
tidine, quinoline, tributylphosphine, trioctylphosphine, tri-
laurylphosphi~e or triph~nylphosphine. It is also possible
to use organonitrogen or organophcsphorus compounds quater~
nized with methyl halide or hydrogen halide, e g in the
form o~ N-methylpyridinium halide, N,N-dime~thylimidazollum ~
halide, N-methyl-3-picolinium halide~ N-methyl-2,4-lutidinium
halide, N-methyl-~,4-lutidinium halide, N-methyl-quinoli~ium
halide, tributyl-methylphosphonium halide, trioctyl-methyl-
phosphonium hzlide, trilauryl-methylphosphonium halide, tri
3~
phenyl-methylphosphonium halide, the halide being in each case chloride,
bromide or iodide. The useful organic arsenic and antimolly compounds
preferably lnclude arsines and stibines.
Acetates of potassium, rubidium or cesium should preferably be
used as alkali metal compounds.
The composition of the feed gases may vary between 100 volume %
C0 and 20 volume % C0 + ~0 volume % H2j it is preferable however to use C0
and l-l2 in a ratio by volume of 90 : lO to 50 : 50.
The reaction should preferably be effected at temperatures of
120 to 250C and under pressures of 10 to 300 bars.
The reaction is carried out in an autoclave made up of corrosion-
p:roof material, e.g. stainless steel or enameled steel over a period of
l to 10 hours. It is also possible for it to be effected within shorter
periods of time which permit the reaction to be effected continuously in a
tlow reactor.
Example l
250 g methyl acetate, 50 g methyl ioclide, 60 g N,N-dimethyl-
imidazolium iodide and 2 g dirheniumdecacarbonyl ~Re2(~0)10) were placed in
a corrosionproof stainless steel reactor having a capacity of 1 liter.
After introduction of ~0 bars C0 and 20 bars hydrogen, the autoclave was
heated to 200C. A maximum pressure of 150 bars was found to establish.
After a sojourn time of about 100 minutes under reaction conditions, the
pressure in the autoclave dropped to 70 bars. The whole was worked up
distillatively and 126.6 g acetic anhydride, 32.5 g ethylidene
diacetate and 54.2 g ace-
~3
33~
tic acid were obtained.
Example 2
~he autoclave was fed with a mixture of 250 g methyl
acetate, 50 g N-methylimidazole, 50 g methyl iodide, 50 g
methyl chloride and 1.5 g Re2(C0)10. After introduction o~
90 bars C0 and 20 bars H2 and establishment of the reaction
temperature of 210C, a ~ressure of 175 bars was ~ound to
prevail inside the autoclave. A~ter a reaction period o~
1 hour, it was ~ound to ha~e dropped to 70 bars. The reac-
tion mixture was worked up distillatively. 135 g acetic
anhydride, 28 g ethylldene diacetate and 32 g acetic acid
were obtained together with unchanged methyl iodide and
unreacted methyl acetata.
Example 3
The rssidue obtained a~ter distillative wor!~ up as
described in Example ~ was admixed with 250 g methyl acetate
and 50 ~ methyl iodide, and used again as catal~s-t, C0-pres-
sure = 80 bars; H2-pressuro = 20 'oars. At a reaction tempe-
rature of Z00C the pressure inside the autoclave dropped
within 30 minutes ~rom 150 to 65 bars. Next9 a ~urther 150
bars C0 was introduced until C0 ceased to be taken up. A~ter
altogether 100 minutes, the reaction was terminated. The
whole was wor~ed up distillatively and 290 g acet~c anhydride,
5.5 g ethylidene diacetate and Lo g acetic acid were obtained
together with unchanged methyl iodide. Methyl acetate was
detectable in traces only,
Example 4
Feed materials used: 250 g methyl acetate
g methyl iodide
1.5 g Re2(C0)10
The autoclave was scavenged with argon and 20 bars H2
and 80 bars C0 were introduced thereinto, At a temperature
OL 200C, the pressure inside the autoclave dropped within
2 hours from 160 to 70 bars. 118 g acetic anhydride, 23 g ethylidene diacetate and 12 g acetic acid were obtained.
Example 5
Feed materials used: 250 g methyl aceta~e
g methyl iodide
g cesium acetate
1-5 g Re2(C)10
C0-~ressure = 80 ~ars; ~2-prossure = 25 bars at 20C. A re-
action temperature of 205C was established. A~ter a reac-
tion period o~ 2.5 hours the pressure insid~ the autoclave
dropped ~rom 160 bars (maximum) to ~0 barst u~der the reac-
tion conditions. The material wa~ distillatively separ~ted
and 102 g acetic a~hydride, 25 g acetic acid and 28.8 g
ethylidane diacetate were obtained togsther with unreacted
meth~l acetate.
Example 6
Feed materials used: 250 g me~hyl acetate
50 g methyl iodide
1-5 g Re2(C)10
1C g methyl-tributylphos-
phonium iodide
80 bars C0 and 20 bars H2 were introduced at 20C. At
a reaction temperature of 205C, the pressure inside the
autoclave increased up to 180 bars. A~ter 1.5 hours the re-
action was ter~ïnated. 167.7 g acetic anhydride, 1.5 g ethy-
lidene diacetate and 34 g acetic acid were o'otained from the
3~
reaction product
Example 7
The residue which was obtained after distillative work
up as described in Example 4 was removed from the distilling
flask, taken up in aqua regia and ooncentrated to dryness.
Next it was aomixed with 250 g methyl acetate, 50 g methyl
iodide and lO g N~N-dimethylimidazolium iodide and used as
catalyst. C0-pressure = 85 bars at 20C; H2-pressure = 20 bars
~t 20C. At a reaction temper~ture of 210~C, the reactio~ pres-
13 sure inside the autoclave dropped within 110 minutes to 70
bars.
197.7 g acetic ar~ydride, 17 g ethylidene diacetate and3~ g acetic acid wero obtained
Example 8
The residue obtained a~ter distillative work up as des-
cribed in Example 5 was treated as described in Example ~,
250 g methyl ~cetate, 50 g methyl :iodide and 10 g N,M-di--
methylimidazolil!m iodide were added, 100 bars C0 (wit~out
hydrogen) were introduced and the whole was heated to 210C.
20 ~he ~ressure inside the autoclave increased up ta 185 bars.
After 3.5 hours, the pressure wa~ ~ound to have dropped to
70 bars. Distillative work up yielded 246.7 g acetic an-
hydride and 20 g acetic acid~
Example 9
250 g methyl acetate, 100 g mèthyl bromide, 30 ~ N-methyl-
imidazole and 1.5 g Re2(C0)1~ were placed in the autoclave.
This latter was scavenged with argon and 80 bars C0 and 20
bars H~ were introduced thereinto. At a temperature of 215C
the pressure dropped within 6 hours from 180 bars to 90 bars.
After cooling and distillative work up 9 70 g acetic anhy-
dride and 46 g acetic acid were obtained. ~thylidene di
acetate could not be found to have been ~ormed in this
Example.
Example 10
Feed materials used: 25Q g methyl acetate1 50 g methyl
iodide, 60 g N~N-dimeth~limidazolium iodide, 1,5 g Re2(C0)10,
1 g I2, 80 bars C0, 20 bars ~2~
The autoclave was heated to 220C and the pressure
dropped within 130 minutes from 165 to 70 bars. The reaction
product wa~ worX@d u~ distillativel~J and founcl to contain
122 ~ acetic anhydride, 4~ g acetic acid and 12 ~ ethyli-
dene diacetate.
Example 11
250 g methyl acetate, 50 g methyl iodide, 60 g N~N-di-
methylimidazolium iod~de, 1.7 g ReCl5 and 0,87 g rhenium me-
tal were placed in ~he autoclave. 80 bars C0 and 20 bars H2
wer~ int~oduced. 135 g acetic anhydride and 20 ~ acetic acid
were obtained after a reaction period of 3 hours a~ 185~C.
Ethylidene diacetats could ~ot be found to have been formed.
Example 12
A mixture of 250 g methyl acetate, 50 g methyl iodide,
60 g mathyl-tributylphospho~ium iodide and 1.5 g Re~(CO)10
was placed in the autoclave. Next, 80 bars C0 and 20 bars H2
were introduced. 155 g acetic anhydride/ 23 g acetic acid
and 6 g ethylidene diacetate were obtained within 5 hours at
a reaction ter~perature of 215 to 2~0C.
