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Patent 1094101 Summary

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(12) Patent: (11) CA 1094101
(21) Application Number: 263310
(54) English Title: PROCESS FOR THE MANUFACTURE OF ACETIC ACID ETHYL ESTER
(54) French Title: PROCEDE D'OBTENTION INDUSTRIELLE D'ETHYLESTER D'ACIDE ACETIQUE
Status: Expired
Bibliographic Data
(52) Canadian Patent Classification (CPC):
  • 260/495.4
(51) International Patent Classification (IPC):
  • C07C 69/14 (2006.01)
  • B01J 21/08 (2006.01)
  • B01J 27/02 (2006.01)
  • B01J 31/02 (2006.01)
  • C07C 67/04 (2006.01)
(72) Inventors :
  • LEUPOLD, ERNST I. (Germany)
  • ARPE, HANS-JURGEN (Germany)
  • RENKEN, ALBERT (Germany)
  • SCHLOSSER, ERNST-GUNTHER (Germany)
(73) Owners :
  • HOECHST AKTIENGESELLSCHAFT (Germany)
(71) Applicants :
(74) Agent: BERESKIN & PARR LLP/S.E.N.C.R.L.,S.R.L.
(74) Associate agent:
(45) Issued: 1981-01-20
(22) Filed Date: 1976-10-13
Availability of licence: N/A
(25) Language of filing: English

Patent Cooperation Treaty (PCT): No

(30) Application Priority Data:
Application No. Country/Territory Date
P 25 45 845.1 Germany 1975-10-14

Abstracts

English Abstract



HOE 75/F 266

Process for the Manufacture of Acetic Acid Ethyl Ester
Abstract of the Disclosure:
Acetic acid ethyl ester is prepared by passing ethylene
over a fixed-bed catalyst composed of silicon dioxide, which
has a surface from 50 to 200 m2/g and which is impregnated
with H2SO4, diethylsulfate or ethylsulfuric acid or mixtures
of these compounds, with periodically alternating quantities
of acetic acid, at a temperature from 130 to 170°C, the
acid concentration, calculated on ethylene, varying constant-
ly over a range from 0,01 to 40 % by mole,


Claims

Note: Claims are shown in the official language in which they were submitted.


HOE 75/F 266


THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:


1. A process for the preparation of acetic acid ethyl
ester in the gaseous phase in which ethylene is passed over a
fixed-bed catalyst with periodically alternating quantities of
acetic acid at a temperature of from 130 to 170°C, the catalyst
being composed of silicon dioxide having a surface of from 50 to
200 m2/g which is impregnated with at least one member of the
group of H2SO4, diethylsulfate and ethylsulfuric acid, the acetic
acid concentration, calculated on ethylene, varying constantly
over a range of from 0.01 to 40% by mole.


2. A process as claimed in claim 1, in which the acetic
acid ethyl ester is separated continuously from the reaction
mixture, unreacted portions of acetic acid and ethylene are sepa-
rated and these unreacted portions are returned to the reaction.


3. A process as claimed in claim 1, in which any lost
H2SO4, diethylsulfate or ethylsulfuric acid is recovered.


4. A process as claimed in claim 1, claim 2 or claim 3
in which the acetic acid is added alternatingly by interrupting
the addition in certain intervals.



5. A process as claimed in claim 1, claim 2 or claim 3
in which the reaction is carried out at a temperature from 140 to
150°C.


6. A process as claimed in claim 1, claim 2 or claim 3
in which the silicon dioxide used has a surface from 80 to 170

11

HOE 75/F 266

m2/g.

7. A process as claimed in claim 1, claim 2 or claim 3
in which the acetic acid concentration varies over a range from
0.1 to 30% by mole.

12

Description

Note: Descriptions are shown in the official language in which they were submitted.


~ 110~ ~5/~ 66

`: :
The present invention rela-tes to a process ~or -the con
tinuous manufact1lre of ace-tic acid ester by addition o~
acetic acid to ethylene.
It is known to react ace-tic acid in the pre.sence of
acidic catalysts wi-th ethylene to yield ace-tic acid ethyl
ester. In the litera-ture several proposals have been made
concerning the catalysts and -the operation rnethods. A sum-
mary of these proposals has been published by ~. ~lurakami,
T. Ha-ttori and H. Uchida in J. Chem. Soc~ Japan, Ind. Chem.
Sect. (l~ogyo I~agaku Zasshi) 72 (9), 19~15 - 19l~ (-1969).
' It can be-seen therefrom that catalys-ts con-taining oxides
of chromium, molybdenum and wolfram in -the form of diffe-
rent heteropoly acids~ which are used for the ca-talysis in
the gaseous phase, show a certain ini-tial activity at reL~
tively high -tempera-ture of more than 200 C and under a
pressure of up -to 150 bars, but become nearly inactive atfter
a few hours already. Ca-talysts containing phosphoric acid
H3P0~ to be used for the reac-tion in a gaseous phase are un-
suitable because of their low activity. ~cidic :ion exchange
resins cannot be used owing to t;heir instability already at
temperatures even below -the required reaction -temperature.
Considerable difficulties also arise ~hen performing
the reaction in the liquid phase. For -this rea~son a por-tion
of 67 % of a sulfur:ic acid of 96 /0 strength, calculated on
~5 acctic acid to be reactecl, -t'or example, has been proposecl in
the reaction zone~ for the manufacture of acetic ac:id e-thyl
ester f~rom acetic acid and ethylene.
It is~ however, known -tha-t h:igh concerltrations of rmine-
ral acids lead -to a partial polymerization of et;hylene a1~d,



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~-IOI~, 7~ 266
~ Q~


consequently9 to losses o~ ethylene and -to polymer by-
produc-ts, which can only be removed ~lth d;~ficul-ties ~`rc)m
the cataly~st solu-tion. A ~urther substantial disadvantage
of mineral acids o~ high concentration resides in the -~act
-that they bring about considerable corrosion problems, which
hinder their use on an inclus-trial scale~
As a summary i-t can be said tha-t none of the me-thods
proposed in the li-terature has proved appropriate ~or an
economic manu~acture of acetic acid es-ters on an indus-trial
scale~
The present invention consequen-tly provides a process
~or the manut'acture o~ acetic acid ethyl ester by reac-tion
o~ acetie acid and ethylene in the gaseous phase in -the pre-
sence o~ acidic ca-talysts~ which comprises passing ehtylene
over a -~ixed-bed catalys-t wi-th periodically al-ternating quan-
tities of acetic acid a-t a temperature ~rom 130 -to i70 C~
the catalyst being composed of silicon dioxide, ~hich has a
sur~ace ~rom 50 to 200 m /g and is impregnated with ~l2SOl~ or
; diethyl sulfate or ethylsul~ate acid or mixtures o~ these
compounds, the ace-tic acid concentration, calculated on
ethylene, varying constantly over a range ~rom o.o1 to 40 %
by mole.
The process according to the invention has surprisingly
; decisive advantages as compared to the previously proposecl
2S methods. One advantage resides in -the ~act -tha-t the e~fi~
ciency o~ the catalyst according to the invention is nearly
~mchanged under -the reaction concl:Ltions even a~-ter more
than 100 hours. The other a~vantage resides in the fact
that -there are prac-tically no losses o~ ethylene due to




- 3 ~




:' ,' :'; ; ::

~ /F 266



polymerizat:ion A :~orma-tion o~ by-pro~ucts or unclesired
consecutive produc-ts can nvt at all be ohserved~
The process according -to -the inven-tion can be performed
in the fo~1lowing manner generally: Ethylene and acetic acid
in a gaseous state are passed -through a reaction zone in a
reactor, in which -the ca-talys-t is arranged as a iixed-bed.
In this process acetic acicl may ei-ther be passecl ove:r a pre-
evaporator or be lead directly to the reaction zone, where
~ it vaporizes immediately under -the reac-tion conditions
A hea-table -tube, which may be made of glass or stai.n-
less steel, ~or example~ may serve as a reaction zone~ in
which the catalys-t is arranged as a fixed-bed. Other reac-
tor forms and materials may also be used, however
The reaction tempera-ture is in the range ~rom 130 to
15 170 C, preferably from 140 to I50 C~ sligh-tly higher or
lower temperatures being also possible~
A pressure range from 0.5 -to 10 bars is suitable for
the process according to the invention, but hig:her pressures~
for e~ample up to I00 bars~ may also be applied without ~!
di~ficulty.
The service life of the catalyst as well as the space-
time-yield o~ the catalys-t in -the process o~ -the invention
a:re defined in characteristic manner by the ace-tic acid con-
centration in the reactor. The permanent varlation o:f -the
ace-t;ic acid concentration in the reac-tor is in a :range
between a min:imwn value and a maximum value f:rom 0.01 to
40 % by mole~ calcula-ted on e-thylene, is particula:rly advan-
ta~eously achieved in definite lnterva:Ls.
Th:is peImanent variation may be achieved rnos-t easily,

.


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,.
for example by continuously regulating the acetic acid ad-
r~ssion in ~eriods, durinq which aeld is added~d d~r~la whieh ~2
addition is dieontinued by mec~s of a t~ switeher.
The duration of these intervals with or withou-t acid
addition depencls subs-tan-tially on -the desorp-tion veloci-ty
Or the ace-t:ic acid ~rom -the catalys-t under -the reaCtior1 con-
ditions. ~s acetic aci.d is absor'bed by the catalyst -to a
higher degree than ethylene, -the cataly-tically ac-tive sur-
. face o~ the.ca-talys-t woulcl be subs-tan-tially covered wi-th
ace-tic acid alone already af-ter a shor-t period of -time,when
~orking withou-t'inte:rruption of the ace-tic acid addition,
and as a consequence thereof only a ~ery small part o~ ethy
lene would be ac-tivated, -thus considerably red-1ci.ng -the
ester formation veloci-ty. I:n practice it may also be advan-

tageously opera-ted in the ~ollowing manner: Ace-tic acid is
introduced into -the reac-tor during an in-ter~al from 2 -to 60
minutes, :for example 9 preferably 5 to 30 minutes, and -the
addition ls -then interrup-ted ~or each time 0.1 -to '15 minutes~
p:referably 1 -to 10 mi:nu-tes, while e-thylene is adcled -~i-t'hou-t
in-terruption. ~s a consecluence of such a repea-ted discon-
tinuance of -the ace-tic acid adclition a part of -the acetic
acid absorbed by the ca-talys-t is desorbed again and again
so t:hat a su~`ficien-t quan-tity of ethylene is likewise ab-
sorbed genera:lly~
Si02 used ~or t:he manufac-ture of -the ca-talyst :has a
specific surrace from 50 -to 200 m /g, p:ref`erably ~rom ~0 to
170 m /g. Considerably larger or s~aller .ju:r:faces may 'Leac1
to no-ticeably reduced yields of ace-tic ac:id e-thyl es-te:r.
The ca-talyst ma-~ generally -be prepa:rec1 in -the following




- 5 ~



: . . :
: :~: j~. : :
.. . . .

~ 5~ 66

- .
manner: SiO2 is impregn~ted with ~12SOLI and/or diethylsul~`ate
or ethylsul~uric acld o:r with mix-tures of these compoul1ds,
preferably in admix-ture with acetic acid, and dried subse
quently under a reduced pressure at a temperature of abou-t
lL~o C. Among the catalys-ts prepared in said manner there
are preferably used those having a conten-t of H2S04 ancl/or
diethylsulfa-te and/or e-thyl.sul~uric acid or mixtures of
these compounds from about 10 to 30 % by- weight, op-tionally
a~ter removal o~ the acet:ic acid by drying.
I~ -the material load of the catalyst is too high duri.ng
the reaction a small discharge and, consequently~ losses of
the impregna-tion may occur whereby the space--time--yield o:f
the catalyst may be sligh-tly reduced in the course of seve-
ral hundred hours. In such cases it has proved advantage-
ous to introduce H2S04 and/or diethylsulfate and/or ethy].~
sulfuric acid dissolved in acetic acirl into the reactor to-
gether with the reaction components in an amount f:rom about
O.i to about 2 /0 by weight, calculated on the acetic acid
introduced into -the reactor.
The reaction product may be worked up continuou~sly or
discontinuously by applying the known methods. The preferr-
ed method consists in separating the reac-tion mixture con-ti-
nuously while isolating p-ure acetic acid ethyl este-r. For
this purpose the reaction mixtnre is cooled af-ter having
le~t the reac-tor9 whe:reby e-thylacetate and non conver-ted
acetic acid condense, whereas non convertecl eth~lene is se
para-ted in a gaseous state and recycled to the reactor. The
condensate is preferablr con-t:inuously submlt-ted to a frac-
tionnated distillation~ whereby non converted acetic acid

"- 6 _

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.. :' : .. . ` ~I' ' ' ~, ..

"' - . ' ~ ' ' , , ' .

~ f I~ r 266

., .
is recovercd from the bottom prod-uct of the distillation
column and recycled to the reac-tor, whereas pure acetic acid
ethyl. ester is obtained at -the top of -the column.
The selectivity of the process according to the inven-

tion is extremely high; i-t is nearly 100 o~h, referring to
acetic acid as well as to ethylene.
Ace-tic acid ethyl ester is used to a considerable ex~
tent, for example, as a solven-t for lacquers and adhesives.
. - The follo~ing examples illustra-te the invention:
E X A M P L E S 1 to 3:
- A -total of 10 rnl/h of acetic acid is introduced by
pump,ing alterna-tingly by means of a dosage pump, while simul-
taneously adding 20 Nl/h of ethylene~ at the top o.f a verti-
cally arranged glass -tube reactor of 30 cm length and 100 ml
volune~ ~hich is filled wi-th about 100 ml of a catalyst com-
posed of SlO2, impregnated with 25 % by weight of H~SOl~ and
having a certain-surface as indicatecl in Table 1 and which
is hea-ted to a tempera-ture of 138 C, the acetic acid addi
tion being inte:rrupted constantly for 2 min-u-tes a.~ter 6 mi-

nutes. The reaction mixture leaving the reactor is broughtto normal temperature, liberated from e~cess ethylene and
analysed. It contai.ns besides non converted ace-tic acid
only ace-tic acid ethyl ester so that the selectivitles cal
culated on conver-ted ethylene as well as on converted acetic
acid are practically 'lO0 %. Table 1 indicate.s the conten-t
of ace-tic acid ethyl cster in -the react,ion mixture libera-t-
ed ~rom ethylene of the ~xamples 1 to 3. The non convertcd
portions of ethylene and acetic acid may be :recycled to the
reactor wlthout particular purifying operations.



. . .
~ 7



: : . ~ . : . : :~: : .

I-lOi~ 7'~ ?6-6

T ~ B L E
Influence of` the ca-talyst surf`ace on the conve:rsion
Example SiO2-surface /c by weight of acetic acid e~yl
2 es-ter in the reaction mixture
(m /g) .. ~
1 l10 3~.2
2 120 60,0
3 160 37.4
. . . . __

C 0 M P-A ~ A T I V E E X A M P L E S 1 and 2: -
It is operated in the same manner as in E~amples 1 to
3~ e~Ycept that comparable catalysts are used having a SiO2
surface other than that according -to the inven-tion. Table 2
shows the results obtained. The portions of acetic ac:id
ethyl ester in the reaction mixture are noticeably smaller.
T A B L E II
Influence of -the ca-talyst surface on the conversion
Compara-tive SiO2-surface % by weight of acetic acid
Example (In /g) ethyl ester in the reaction
mi~ture
._ .. . _. _ _ . ~
20 1 o.6 1L~.6
2 35 _ 10.0
E X A M P L E S 4 to 7:
The apparatus described in the Examples 1 to 3 is :t`ill-
ed each time with 100 m] of a ca-talyst (carriero SiO2 ha~ing
a surface of 120 m /g) pr~vided with the impregnation indi-
cated in Table 3 and fed with ethylene and acetic acid in an
analogous manner to Examples 1 to 3. The reaction tempera-
ture in the reactor is 11~4 C. Table 3 indicates the por-
tions of acetic acid ethyl ester in the reaction mixture.




' ' '': . :
:~ :: : - - 'l

~ 1l01~'-~ F 266

--
The selectivl-ti.es, calcula-ted on conver-ted ace-tic acid

as well a.s on con~er-ted ethy1.ene)in the Examples 4 to 7 are
1 0 0 % .
T A B L E III

5 Influence of the catalyst impregnation on the conversion

Example Impregna-tion by weigh-t /0 by weight of ace-tic
(each time 20 % by acid e-thyl es-ter in
. weigh-t) the reac-tion mix-ture

4 H2S04 61.5

. di.ethylsulfate 59.2
.. . 6 ethylsulfuric acid 59-7
_ _ ,. . ., ..... __ .. _. ._ ' O 1

E X A M P L E S 8 to 10:

c~00 Nl/h of ethylene as well as alternatingly acetic
acid having a content of diethylsulfate of 0~7 % by weight
are introdueed continuously at the top of a vertically ar-
ranged V4A steinless steel reactor of 100 cm leng-th, whieh
is filled with 250 ml of catalys-t (SiO2, 120 m /g, 25 o~b by
weight of diethylsulfate), at a -temperature of 147 C. The
alternating acetic acid addition is carried out in the fol-
lowing manner: The acldi-tion is interrupted each -time for
one interval af-ter 5 dosing intervals. A total of 150 ml/h
of acetic acid is metered into the reactor, The pressure in
the reactor is 6 bars. The reaction mi~ture leaving the
reactor is worked up continuously. The e~cess ethylene is
recycled to the reac-tor. The portion of the reac-tion mi.x-
ture liquid ~t normal temperature is fractiona-ted in a di.
s-tillation column. The acetic ac:id ethyl ester is withdrawn




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10~4101 ~IOF 75/F ~>6

at the top of the column. A mixture containing besides small
quantitie~ of acetic acid ethyl ester unconverted acetic acid
is recycled to the reactor continuously from the bottom.
Table 4 indicates the different intervals of the alternating
acetic acid addition of the Examples 8 to 10 as well as the
space-time-yields obtained. The selectivities for acetic
acid ethyl ester, calculated on converted ethylene and con-
verted acetic acid, are in all cases 100 ~.
T A B L E IV

Example Intervals of the acetic Space-time-yield of the
acid addition (min) acetic acid ethyl ester
addition without formation (g/l.h)
addition

8 5 1 205
9 12.5 2.5 178
164


The same values for the space-time-yield of the acetic
acid ethyl ester formation as well as the same selectivities
are obtained even after a continuous operation time of more


than 1000 hours.
C 0 M P A R A T I V E E X ~ M P L E 3:
~ len operating in the same manner as in the Examples 8
to 10, except that the acetic acid addition is not perform-
ed alternatingly, but that 150 ml/h of acetic acid are added
without interruption, the space-time-yield of the acetic
acid ethyl ester formation is only 100 g/l . h.




-- 1 0

Representative Drawing

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Administrative Status

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Administrative Status

Title Date
Forecasted Issue Date 1981-01-20
(22) Filed 1976-10-13
(45) Issued 1981-01-20
Expired 1998-01-20

Abandonment History

There is no abandonment history.

Payment History

Fee Type Anniversary Year Due Date Amount Paid Paid Date
Application Fee $0.00 1976-10-13
Owners on Record

Note: Records showing the ownership history in alphabetical order.

Current Owners on Record
HOECHST AKTIENGESELLSCHAFT
Past Owners on Record
None
Past Owners that do not appear in the "Owners on Record" listing will appear in other documentation within the application.
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Document
Description 
Date
(yyyy-mm-dd) 
Number of pages   Size of Image (KB) 
Drawings 1994-03-09 1 14
Claims 1994-03-09 2 54
Abstract 1994-03-09 1 23
Cover Page 1994-03-09 1 23
Description 1994-03-09 9 395