CA1107758A - Process for the manufacture of acetic acid - Google Patents
Process for the manufacture of acetic acidInfo
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- CA1107758A CA1107758A CA293,780A CA293780A CA1107758A CA 1107758 A CA1107758 A CA 1107758A CA 293780 A CA293780 A CA 293780A CA 1107758 A CA1107758 A CA 1107758A
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- reaction
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- oxygen
- peroxide
- acetic acid
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/16—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation
- C07C51/21—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen
- C07C51/23—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of oxygen-containing groups to carboxyl groups
- C07C51/235—Preparation of carboxylic acids or their salts, halides or anhydrides by oxidation with molecular oxygen of oxygen-containing groups to carboxyl groups of —CHO groups or primary alcohol groups
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- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Low-Molecular Organic Synthesis Reactions Using Catalysts (AREA)
Abstract
PROCESS FOR THE MANUFACTURE OF ACETIC ACID
Abstract of the disclosure:
Acetic acid is produced by oxidizing acetaldehyde at elevated temperature in the liquid phase using oxygen or gases containing oxygen in the presence of one or more heavy metal compounds as the catalyst, and adding to the reaction mixture at the start of the addition of oxygen one or more organic peroxides which under the reaction conditions decompose, with a half-life up to 350 minutes, into free radicals in order to initiate the reaction.
Abstract of the disclosure:
Acetic acid is produced by oxidizing acetaldehyde at elevated temperature in the liquid phase using oxygen or gases containing oxygen in the presence of one or more heavy metal compounds as the catalyst, and adding to the reaction mixture at the start of the addition of oxygen one or more organic peroxides which under the reaction conditions decompose, with a half-life up to 350 minutes, into free radicals in order to initiate the reaction.
Description
-`- 11~77S8 HOE 76~F 316 `
Processes for the manufacture of acetic acid by oxi-dizing acetaldehyde at elevated temperature in the liquid ph--_e using oxygen or gases containing oxygen in the presence of soluble heavy metal compounds as catalysts are already kno~m, S Manganese compounds and/or cobalt compounds are preferably us~d as the heavy metal compounds (see Ullmann~s "Enzyklopadie der technischen Chemie" ("Encyclopaedia o~ Industrial Chemistry"~, volume 6, 3rd edition, 1955, page 781 et seq, and German Offenlegungsschrift 2,513,678), ? a - In general, the reaction mixture leaving the reactor still contains 3 - 5 % by wQight of unreacted acetaldehyde, since less than the equivalent amount of oxygen is employed.
A specific embodiment of the process, described in German Offenlegungsschrift 2,514,095, u~es an additional second reacto., In this, a slight excess of oxygen is employed and a viriual~-~-aldehyde-free crude acid is-thus obtained, At the same t ~, this also makes it possible for the heavy metal salts used as the catalyst to be recycled without loss in activity. Bot:^
process variants are operated continuously without ~roblems.
However, there are difficulties if the installations must ce set in operation agai.n after being disconnected, for ex~mpl b,~
power failure, This is particularly true if there is ~
period of ten minutes or more bet~een the disconnectlon and ~h re-operation.
Experience has sho~ that tne re~ction does not ~e~^in immediately when acetaldehyde and ox~en are fed in ag?~n, Un~er certain circwmstan^es, the delay in t~e start-u~ o4 th~
reaction can be several hours.
;~ ~
. , ~F 1.
~ 1-~7758 There is thus a particular interest in ensuring that the reaction begins immediately after such an interruption or when the reaction is started with fresh reactor contents.
The addition of isobutyraldehyde as a start accelerator, and in particular in an amount of 0.3 - 5 % by weight, is thus claimed in German Auslegeschrift 2,520,976. In the example given therein, the mixture used for the oxidation additionally contains 3 ~ of isobutyraldehyde, in addition to acetic acid and 3 % of acetaldehyde. It is indicated that the reaction then starts immediately.
Comparison experiments carried out (see comparison Examples 1 and 2) resulted in an approximate halving of the start-up time from about 56 minutes (without the addition) to about 28 minutes (with the addition of 3 ~ of isobutyraldehyde), under identical operating conditions. However, the delay with respect to time in the start-up of the reaction depends on various circumstances, such as, for example, the period of interruption in operation and the content of acetaldehyde, of impurities and of catalyst. The results can therefore be compared exactly only when the same reaction mixture is u~sed. However, it can be concluded from the statements made in German Auslegeschrift 2,520,97~ and on the basis of the comparison experiments carried out that in order to achieve a good effect, that is to say a short start-up time of the reaction, consi~erable amounts of isobutyraldehyde must certainly be added to the reaction mixture.
Processes for the manufacture of acetic acid by oxi-dizing acetaldehyde at elevated temperature in the liquid ph--_e using oxygen or gases containing oxygen in the presence of soluble heavy metal compounds as catalysts are already kno~m, S Manganese compounds and/or cobalt compounds are preferably us~d as the heavy metal compounds (see Ullmann~s "Enzyklopadie der technischen Chemie" ("Encyclopaedia o~ Industrial Chemistry"~, volume 6, 3rd edition, 1955, page 781 et seq, and German Offenlegungsschrift 2,513,678), ? a - In general, the reaction mixture leaving the reactor still contains 3 - 5 % by wQight of unreacted acetaldehyde, since less than the equivalent amount of oxygen is employed.
A specific embodiment of the process, described in German Offenlegungsschrift 2,514,095, u~es an additional second reacto., In this, a slight excess of oxygen is employed and a viriual~-~-aldehyde-free crude acid is-thus obtained, At the same t ~, this also makes it possible for the heavy metal salts used as the catalyst to be recycled without loss in activity. Bot:^
process variants are operated continuously without ~roblems.
However, there are difficulties if the installations must ce set in operation agai.n after being disconnected, for ex~mpl b,~
power failure, This is particularly true if there is ~
period of ten minutes or more bet~een the disconnectlon and ~h re-operation.
Experience has sho~ that tne re~ction does not ~e~^in immediately when acetaldehyde and ox~en are fed in ag?~n, Un~er certain circwmstan^es, the delay in t~e start-u~ o4 th~
reaction can be several hours.
;~ ~
. , ~F 1.
~ 1-~7758 There is thus a particular interest in ensuring that the reaction begins immediately after such an interruption or when the reaction is started with fresh reactor contents.
The addition of isobutyraldehyde as a start accelerator, and in particular in an amount of 0.3 - 5 % by weight, is thus claimed in German Auslegeschrift 2,520,976. In the example given therein, the mixture used for the oxidation additionally contains 3 ~ of isobutyraldehyde, in addition to acetic acid and 3 % of acetaldehyde. It is indicated that the reaction then starts immediately.
Comparison experiments carried out (see comparison Examples 1 and 2) resulted in an approximate halving of the start-up time from about 56 minutes (without the addition) to about 28 minutes (with the addition of 3 ~ of isobutyraldehyde), under identical operating conditions. However, the delay with respect to time in the start-up of the reaction depends on various circumstances, such as, for example, the period of interruption in operation and the content of acetaldehyde, of impurities and of catalyst. The results can therefore be compared exactly only when the same reaction mixture is u~sed. However, it can be concluded from the statements made in German Auslegeschrift 2,520,97~ and on the basis of the comparison experiments carried out that in order to achieve a good effect, that is to say a short start-up time of the reaction, consi~erable amounts of isobutyraldehyde must certainly be added to the reaction mixture.
2~ However, this has the disadvantageous result that in order to separate off the iso~utyric acid formed in the reaction particular distillation measures are required in working up the reaction ~ 77~8 mixture to give industrially pure acetic acid. In the case of an industrial reactor having a capacity of about 20 m3, an addition of 3 ~ would mean an amount of isobutyraldehyde of 600 kg, which correspond to about 730 kg of isobutyric acid.
The problem was to find start accelerating additives of high activity which do not have the disadvantage mentioned.
It has now been found, surprisingly, that certain peroxidic compounds are quite outstanding start accelerators. The process according to the invention for tXe manufacture of acetic acid by oxidizing acetaldehyde at elevated temperature in the liquid phase using oxygen or gases containing oxygen in the presence of one or more heavy metal compounds as a catalyst comprises adding to the reaction mixture at the start of the addition of oxygén one or more organic peroxides which under the reaction conditions decompose, with a half-life of up to 350 minutes, into fee radicals in order to initiate the reaction. Peroxides with a half-life of 2 to 100 minutes are preferably used.
- In general, the acetic acid synthesis is carried out under pressures of 1 - 20 atmospheres, preferably 1 - 2 atmospheres, and at temperatures from 35 to 150C, preferably 50~ - 70C. Manganese compounds, cobalt compounds or nickel compounds or a mixture of these heavy me~al compounds are preferahly used as the catalyst.
These conditions also apply to the initiation of the reac-tion by the addition of peroxides. Examples of suitable peroxides are peracetic acid, t-butyl hydroperoxide, cumene hydroperoxide, cyclohexanone peroxide or t-butyl perpivalate. Peracetic acid, t-butyl hydxoperoxide, cumene hyroperoxide and cyclohexanone peroxide are preferredO These peroxides have a very high activity, that is to say even additions of 0.01 - 0.1 we~ght ~, relative to the capacity of the reactor, start the reaction in a ~j -3-i~77~
very short time. The addition of amounts of this type is thus preferred.
Larger amounts can, of course, also be added; however, the amounts given are c ~ letely sufficient for the intended purpose.
A particular advantage of these peroxides is that either their decomposition products are separated off with the first runnings in the working up by distillation of the crude acetic acid, or that only substances are formed which are in any case already present in the reaction mixture. Thus, the desired reaction product itself, that is to say acetic acid, is formed from peracetic acid. Since the reaction mixture always contains some water, the decomposition products, such as t-butanol, cumene and cyclohexanone, are present in the first runnings of the crude acetic acid distillation in the form of an azeotrope with water.
The suitability of the peroxides to be employéd for the abovementioned purpose can be deduced from the half-lives. The half-life (that is to say the time after which 50 ~ decomposition of the peroxides has occurred) for some peroxides at 60 % in acetic acid in the presence of catalytic amounts of heavy metal salts (Mn acetate, Co acetate and Ni acetate) was determined (see the following Table~.
Peroxide Half-life in minutes peracetic acid 2 - 3 cyclohexanone peroxide t-butyl hydroperoxide 40 cumene hydroperoxide 9O
t-butyl perpivalate 350 77S~
The peroxides are preferably fed into the main reaction zone, that is to say somewhat above the oxygen inlet, as a solution in acetic acid directly at the start of the oxygen addition. This procedure is particularly advisable in the case of peroxides having a low half-life, such as, for example, peracetic acid and cyclo-hexanone peroxide.
In the abovementioned German Auslegeschrift 2,520,976 itis indicated that the delay in the start-up can be "up to 5 hours".
In order to ensure that the results can be compared exactly, a reaction mixture originating from an industrial installation, 10 such as is obtained therefrom when operation is interrupted, was used for the experiments and two series of experiments were carried out. These were based on two interruptions in operation which took place 4 weeks apart. In each series of experiments, the individual tests were carried out in rapid succession. It was thereby possible to determine the activity of the additives on a comparable basis in each case.
In the start-up time data in the Examples, the symbol ' denotes minutes and the symbol" denotes seconds.
Examples Apparatus:
The reactor consists of a double-walled glass tube, length 2,050 mm, inside diameter 34 mm. The jacket is used, by means of circulating water, for heating and, aft~r the reaction has started, for cooling. The reaction mixture containing acetaldehyde is fed in at the bottom of the reacotr. The oxygen is metered into the reactor by means of a glass frit which is 100 mm above the reaction mixture inlet. For safety reasons, the gas space at the reactor head is flushed with a stream of N2. The reaction mixture leaves the reactor through an overflow at the reactor head and is cooled to about 25 by a downstream cooler. The capacity of the reactor when not charged with gas is 1.~ 1.
An inlet in the side 300 mm above the 2 inlet was added to the reactor for the experiments according to Example 5 - 7 and 8 - 11.
Experimental series I
Comparison Example 1 The reactor described above is filled with a mixture consist-ing of 97 ~ of crude industrial acetic acid and 3 % of:acetaldehyde.
The industrial crude acid also contains, in addition to acetic acid, only traces of acetaldehyde, small amounts of water and a mixture of manganese acetate, cobalt acetate and nickel acetate as the catalyst, the total amount of catalyst being about 0.1 %.
The mixture is warmed to 60 by means of the ja~ket heating.
24 l/hour of oxygen are then metered in via the frit. At the same time, a mixture consisting of 90 ~ of the industrial crude acid described above and 10 % of acetalaehyde is fed in from the bottom in an amount of 1,000 g/hour. The temperature in the reactor is kept a~ 60. The head of the reactor is flushed with 100 l/hour of nitrogen.
Under these conditions, the reaction starts up after 55'55".
The start-up can be recognised exactly, namely by an increase in temperature in the reactor to a maximum of 70 and the collapse of the bubble column as a result of the consumption of oxygen. The start-up is immediately preceeded by a brownish discoloration of the contents of the reactor.
~ -6-~1~7758 Comparison Example 2 The reactor is filled with a mixture consisting of 94 ~ of the industrial crude acid described in Comparison Example 1, 3 %
of acetaldehyde and 3 % of isobutyraldehyde. All the remaining reaction conditions correspond precisely to those from Comparison S Example 1. The reaction starts up after 27'37".
Example 1:
The reactor is filled with a mixture consisting of 96.7 %
of the industrial crude acid described in Comparison Example 1, ~ 3 % of acetaldehyde and 0.3 ~ of t-butyl hydroperoxide. All the ! 10 remaining reaction conditions correspond precisely to those from Comparison Example 1.
The reaction starts up after 1'15", that is to say almost immediately.
Example 2: -The reactor is filled with a mixture consisting of 96.9 %
! of the industrial crude acid described in Comparison Example 1, 3 %
of acetaldehyde and 0.1 % of t-butyl hydroperoxide. All the remaining reaction conditions correspond precisely to those from Comparison Example 1.
The reaction starts up after 2'45".
Exam~le 3:
The reactor is filled with a mixture consisting of 9~.97 %
of the industrial crude acid used in Comparison Example 1, 3 ~ of acetaldehyde and 0.03 % of t-butyl hydroperoxide. A11 the remaining reaction conditions correspond precisely to those from Comparison Example 1.
The reaction starts up after 5'6".
Example 4:
The reactor is filled with a mixture consisting of 96.99 %
of the industrial crude acid used in Comparison Example 1, 3 % of acetaldehyde and 0.01 % of t-butyl hydroperoxide. All the remain-ing reaction conditions correspond precisely to those from Comparison Example 1.
The reaction starts up after 11'50".
Example S:
The reactor is filled with a mixture consisting of 97 % of the industrial crude acid used in Comparison Example 1 and 3 ~ of acetaldehyde. All the remaining reaction conditions correspond to those from Comparison Example 1. However, at the start of the addition of oxygen, a solution of peracetic acid is fed into the reactor through the inlet in the side above the 2 inlét. 25 ml =
26.3 g of a 5.6% strength peracetic acid solution are fed in by means of a metering pump in the course of one minute. This corresponds to a peracetic acid addition of 0.08 %, relative to the total contents of the reactor.
The reaction has already started up when the addition has ended, that is to say in the course of one minute.
2Q Example 6:
The reactor is filled with a mixture consisting of 97 % of the industrial crude acid used in Comparison Example 1 and 3 ~ of acetaldehyde as in Example 5. All the remaining reaction conditions correspond to those from Comparison Example 1. At the start of the addition of oxygen, 16.6 ml = 17.4 g of a 5.6 ~ strength solution of peracetic acid in acetic acid are fed into the reactor through the inlet in the side in the course of about 3 minutes.
,.. ~
~ -8-1~7758 This corresponds to a peracetic acid addition of 0.054 %, relative to the total contents of the reactor.
The reaction starts up immediately after the addition of the amount indicated has ended, i.e. after 3'20".
Example 7:
The reactor is filled with a mixture consisting of 97 ~ of the industrial crude acid used in Comparison Example 1 and 3 ~
of acetaldehyde. all the remaining reaction conditions correspond to those from Comparison Example 1. At the start of the addition of oxygen, a solution of t-butyl hydroperoxide in acetic acid is fed into the reactor through the inlet in the side above the 2 inlet. 10 ml of a 5.6 ~ strength solution are fed in by means of a metering pump in the course of 25". This corresponds to a t-butyl hydroperoxide addition of 0.03 %, relative to the total contents of the reactor.
The reaction starts up after 1'45". c EXPERIMENTAL SERJES ~I
. . .
Comparison Example 3 The reactor described above was filled with a mixture consisting of 97 % of industrial crude acid, which originated from another interruption in operation, and ~ % of acetaldehyde. All the other experimental conditions correspcnd precisely to ~ose from Go~ri-son Example 1. The reaction had not yet started up after 70'; the experiment was therefore discontinued.
Example 8:
The reactor is filled with a mixture consisting of 97 % of the industrial crude acid used in Comparison Example ~ and 3 ~ of acetaldehyde. All the remaining reaction conditions correspond to _g_ 1~77~8 those from Comparison Example 1. At the start of the addition of oxygen, a solution of t-butyl hydroperoxide in acetic acid is fed into the reactor through the inlet in the side above the oxygen inlet. 10 ml of a 5.4 ~ strength solution are fed in by means of a metering pump in the course of 20". This corresponds to a t-butyl hydroperoxide addition of 0.03 ~, relative to the total contents of the reactor.
The reaction thereby starts up after 1'25".
Exam le 9:
The reactor is filled with a mixture consisting of 97 % of the industrial crude acid used in Example 3 and 3 ~ of acetaldehyde.
All the remaining reaction conditions correspond to those from Comparison Example 1. At the start of the addition of oxygen, a solution of cumene hydroperoxide in acetic acid is fed~into the reactor through the inlet in the side above the oxygen inlet. 10 ml of a 5.4 ~ strength solution are fed in by means of a metering pump in the course of 20". This corresponds to a cumene hydroperoxide addition of 0.03 %, relative to the total contents of the reactor.
The reaction thereby starts up after 4'15".
Exam~le 10:
The reactor is filled with a mi~ture consisting of 97 % of the industrial crude acid used on Comparison Example 3 and 3 ~ of acetaldehyde. All the remaining reaction conditions correspond to those from Comparison Example 1. At the start of the addition of oxygen, a solution of cyclohexanone peroxide in acetic acid is fed ~5 into the reactor through the inlet in the side a~ove the oxygen inlet. 10 ml o~ a 5.4 ~ stren~th solution are fed~in ~y means of a meterin~ pump in the course of 20". This corresponds to a ~1~7758 cyclohexanone peroxide addition of 0.03 %, relative to the total contents of the reactor.
The reaction thereby starts up after 17'25".
Example 11:
The reactor is filled with a mixture consisting of 97 % of the industrial crude acid used in Comparison Example 3 and 3 % of acetaldehyde. All the remaining reaction conditions correspond to those from Comparison Example l. At the start of the addition of oxygen, a solution of t-butyl perpivalate in acetic acid is fed into the reactor through the inlet in the side above the oxygen inlet.
lO ml of a 5.4 % strength solution ar~ fed in by mean5 of a meter-ing pump in the course of 20". This corresponds to a t-butyl perpi-valate addition of 0.0~ %, relative to the total contents of the reactor. The reaction thereby starts up after 41'50"., :
The problem was to find start accelerating additives of high activity which do not have the disadvantage mentioned.
It has now been found, surprisingly, that certain peroxidic compounds are quite outstanding start accelerators. The process according to the invention for tXe manufacture of acetic acid by oxidizing acetaldehyde at elevated temperature in the liquid phase using oxygen or gases containing oxygen in the presence of one or more heavy metal compounds as a catalyst comprises adding to the reaction mixture at the start of the addition of oxygén one or more organic peroxides which under the reaction conditions decompose, with a half-life of up to 350 minutes, into fee radicals in order to initiate the reaction. Peroxides with a half-life of 2 to 100 minutes are preferably used.
- In general, the acetic acid synthesis is carried out under pressures of 1 - 20 atmospheres, preferably 1 - 2 atmospheres, and at temperatures from 35 to 150C, preferably 50~ - 70C. Manganese compounds, cobalt compounds or nickel compounds or a mixture of these heavy me~al compounds are preferahly used as the catalyst.
These conditions also apply to the initiation of the reac-tion by the addition of peroxides. Examples of suitable peroxides are peracetic acid, t-butyl hydroperoxide, cumene hydroperoxide, cyclohexanone peroxide or t-butyl perpivalate. Peracetic acid, t-butyl hydxoperoxide, cumene hyroperoxide and cyclohexanone peroxide are preferredO These peroxides have a very high activity, that is to say even additions of 0.01 - 0.1 we~ght ~, relative to the capacity of the reactor, start the reaction in a ~j -3-i~77~
very short time. The addition of amounts of this type is thus preferred.
Larger amounts can, of course, also be added; however, the amounts given are c ~ letely sufficient for the intended purpose.
A particular advantage of these peroxides is that either their decomposition products are separated off with the first runnings in the working up by distillation of the crude acetic acid, or that only substances are formed which are in any case already present in the reaction mixture. Thus, the desired reaction product itself, that is to say acetic acid, is formed from peracetic acid. Since the reaction mixture always contains some water, the decomposition products, such as t-butanol, cumene and cyclohexanone, are present in the first runnings of the crude acetic acid distillation in the form of an azeotrope with water.
The suitability of the peroxides to be employéd for the abovementioned purpose can be deduced from the half-lives. The half-life (that is to say the time after which 50 ~ decomposition of the peroxides has occurred) for some peroxides at 60 % in acetic acid in the presence of catalytic amounts of heavy metal salts (Mn acetate, Co acetate and Ni acetate) was determined (see the following Table~.
Peroxide Half-life in minutes peracetic acid 2 - 3 cyclohexanone peroxide t-butyl hydroperoxide 40 cumene hydroperoxide 9O
t-butyl perpivalate 350 77S~
The peroxides are preferably fed into the main reaction zone, that is to say somewhat above the oxygen inlet, as a solution in acetic acid directly at the start of the oxygen addition. This procedure is particularly advisable in the case of peroxides having a low half-life, such as, for example, peracetic acid and cyclo-hexanone peroxide.
In the abovementioned German Auslegeschrift 2,520,976 itis indicated that the delay in the start-up can be "up to 5 hours".
In order to ensure that the results can be compared exactly, a reaction mixture originating from an industrial installation, 10 such as is obtained therefrom when operation is interrupted, was used for the experiments and two series of experiments were carried out. These were based on two interruptions in operation which took place 4 weeks apart. In each series of experiments, the individual tests were carried out in rapid succession. It was thereby possible to determine the activity of the additives on a comparable basis in each case.
In the start-up time data in the Examples, the symbol ' denotes minutes and the symbol" denotes seconds.
Examples Apparatus:
The reactor consists of a double-walled glass tube, length 2,050 mm, inside diameter 34 mm. The jacket is used, by means of circulating water, for heating and, aft~r the reaction has started, for cooling. The reaction mixture containing acetaldehyde is fed in at the bottom of the reacotr. The oxygen is metered into the reactor by means of a glass frit which is 100 mm above the reaction mixture inlet. For safety reasons, the gas space at the reactor head is flushed with a stream of N2. The reaction mixture leaves the reactor through an overflow at the reactor head and is cooled to about 25 by a downstream cooler. The capacity of the reactor when not charged with gas is 1.~ 1.
An inlet in the side 300 mm above the 2 inlet was added to the reactor for the experiments according to Example 5 - 7 and 8 - 11.
Experimental series I
Comparison Example 1 The reactor described above is filled with a mixture consist-ing of 97 ~ of crude industrial acetic acid and 3 % of:acetaldehyde.
The industrial crude acid also contains, in addition to acetic acid, only traces of acetaldehyde, small amounts of water and a mixture of manganese acetate, cobalt acetate and nickel acetate as the catalyst, the total amount of catalyst being about 0.1 %.
The mixture is warmed to 60 by means of the ja~ket heating.
24 l/hour of oxygen are then metered in via the frit. At the same time, a mixture consisting of 90 ~ of the industrial crude acid described above and 10 % of acetalaehyde is fed in from the bottom in an amount of 1,000 g/hour. The temperature in the reactor is kept a~ 60. The head of the reactor is flushed with 100 l/hour of nitrogen.
Under these conditions, the reaction starts up after 55'55".
The start-up can be recognised exactly, namely by an increase in temperature in the reactor to a maximum of 70 and the collapse of the bubble column as a result of the consumption of oxygen. The start-up is immediately preceeded by a brownish discoloration of the contents of the reactor.
~ -6-~1~7758 Comparison Example 2 The reactor is filled with a mixture consisting of 94 ~ of the industrial crude acid described in Comparison Example 1, 3 %
of acetaldehyde and 3 % of isobutyraldehyde. All the remaining reaction conditions correspond precisely to those from Comparison S Example 1. The reaction starts up after 27'37".
Example 1:
The reactor is filled with a mixture consisting of 96.7 %
of the industrial crude acid described in Comparison Example 1, ~ 3 % of acetaldehyde and 0.3 ~ of t-butyl hydroperoxide. All the ! 10 remaining reaction conditions correspond precisely to those from Comparison Example 1.
The reaction starts up after 1'15", that is to say almost immediately.
Example 2: -The reactor is filled with a mixture consisting of 96.9 %
! of the industrial crude acid described in Comparison Example 1, 3 %
of acetaldehyde and 0.1 % of t-butyl hydroperoxide. All the remaining reaction conditions correspond precisely to those from Comparison Example 1.
The reaction starts up after 2'45".
Exam~le 3:
The reactor is filled with a mixture consisting of 9~.97 %
of the industrial crude acid used in Comparison Example 1, 3 ~ of acetaldehyde and 0.03 % of t-butyl hydroperoxide. A11 the remaining reaction conditions correspond precisely to those from Comparison Example 1.
The reaction starts up after 5'6".
Example 4:
The reactor is filled with a mixture consisting of 96.99 %
of the industrial crude acid used in Comparison Example 1, 3 % of acetaldehyde and 0.01 % of t-butyl hydroperoxide. All the remain-ing reaction conditions correspond precisely to those from Comparison Example 1.
The reaction starts up after 11'50".
Example S:
The reactor is filled with a mixture consisting of 97 % of the industrial crude acid used in Comparison Example 1 and 3 ~ of acetaldehyde. All the remaining reaction conditions correspond to those from Comparison Example 1. However, at the start of the addition of oxygen, a solution of peracetic acid is fed into the reactor through the inlet in the side above the 2 inlét. 25 ml =
26.3 g of a 5.6% strength peracetic acid solution are fed in by means of a metering pump in the course of one minute. This corresponds to a peracetic acid addition of 0.08 %, relative to the total contents of the reactor.
The reaction has already started up when the addition has ended, that is to say in the course of one minute.
2Q Example 6:
The reactor is filled with a mixture consisting of 97 % of the industrial crude acid used in Comparison Example 1 and 3 ~ of acetaldehyde as in Example 5. All the remaining reaction conditions correspond to those from Comparison Example 1. At the start of the addition of oxygen, 16.6 ml = 17.4 g of a 5.6 ~ strength solution of peracetic acid in acetic acid are fed into the reactor through the inlet in the side in the course of about 3 minutes.
,.. ~
~ -8-1~7758 This corresponds to a peracetic acid addition of 0.054 %, relative to the total contents of the reactor.
The reaction starts up immediately after the addition of the amount indicated has ended, i.e. after 3'20".
Example 7:
The reactor is filled with a mixture consisting of 97 ~ of the industrial crude acid used in Comparison Example 1 and 3 ~
of acetaldehyde. all the remaining reaction conditions correspond to those from Comparison Example 1. At the start of the addition of oxygen, a solution of t-butyl hydroperoxide in acetic acid is fed into the reactor through the inlet in the side above the 2 inlet. 10 ml of a 5.6 ~ strength solution are fed in by means of a metering pump in the course of 25". This corresponds to a t-butyl hydroperoxide addition of 0.03 %, relative to the total contents of the reactor.
The reaction starts up after 1'45". c EXPERIMENTAL SERJES ~I
. . .
Comparison Example 3 The reactor described above was filled with a mixture consisting of 97 % of industrial crude acid, which originated from another interruption in operation, and ~ % of acetaldehyde. All the other experimental conditions correspcnd precisely to ~ose from Go~ri-son Example 1. The reaction had not yet started up after 70'; the experiment was therefore discontinued.
Example 8:
The reactor is filled with a mixture consisting of 97 % of the industrial crude acid used in Comparison Example ~ and 3 ~ of acetaldehyde. All the remaining reaction conditions correspond to _g_ 1~77~8 those from Comparison Example 1. At the start of the addition of oxygen, a solution of t-butyl hydroperoxide in acetic acid is fed into the reactor through the inlet in the side above the oxygen inlet. 10 ml of a 5.4 ~ strength solution are fed in by means of a metering pump in the course of 20". This corresponds to a t-butyl hydroperoxide addition of 0.03 ~, relative to the total contents of the reactor.
The reaction thereby starts up after 1'25".
Exam le 9:
The reactor is filled with a mixture consisting of 97 % of the industrial crude acid used in Example 3 and 3 ~ of acetaldehyde.
All the remaining reaction conditions correspond to those from Comparison Example 1. At the start of the addition of oxygen, a solution of cumene hydroperoxide in acetic acid is fed~into the reactor through the inlet in the side above the oxygen inlet. 10 ml of a 5.4 ~ strength solution are fed in by means of a metering pump in the course of 20". This corresponds to a cumene hydroperoxide addition of 0.03 %, relative to the total contents of the reactor.
The reaction thereby starts up after 4'15".
Exam~le 10:
The reactor is filled with a mi~ture consisting of 97 % of the industrial crude acid used on Comparison Example 3 and 3 ~ of acetaldehyde. All the remaining reaction conditions correspond to those from Comparison Example 1. At the start of the addition of oxygen, a solution of cyclohexanone peroxide in acetic acid is fed ~5 into the reactor through the inlet in the side a~ove the oxygen inlet. 10 ml o~ a 5.4 ~ stren~th solution are fed~in ~y means of a meterin~ pump in the course of 20". This corresponds to a ~1~7758 cyclohexanone peroxide addition of 0.03 %, relative to the total contents of the reactor.
The reaction thereby starts up after 17'25".
Example 11:
The reactor is filled with a mixture consisting of 97 % of the industrial crude acid used in Comparison Example 3 and 3 % of acetaldehyde. All the remaining reaction conditions correspond to those from Comparison Example l. At the start of the addition of oxygen, a solution of t-butyl perpivalate in acetic acid is fed into the reactor through the inlet in the side above the oxygen inlet.
lO ml of a 5.4 % strength solution ar~ fed in by mean5 of a meter-ing pump in the course of 20". This corresponds to a t-butyl perpi-valate addition of 0.0~ %, relative to the total contents of the reactor. The reaction thereby starts up after 41'50"., :
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the preparation of acetic acid by oxidizing acetaldehyde at an elevated temperature in the liquid phase using oxygen or a gas containing oxygen in the presence of a catalyst comprising one or more heavy metal compounds, in which at least one organic peroxide, other than peracetic acid, which under the reaction contitions decomposes, with a half-life of up to 350 minutes, into free radicals, is added to the reaction mixture at the start of the addition of oxygen in order to initiate the reaction.
2. A process as claimed in claim 1 in which the half-life of the peroxide is 2 to 100 minutes.
3. A process as claimed in claim 1 in which the peroxide is selected from the group of t-butyl hydroperoxide, cyclohexanone peroxide or cumene hydroperoxide.
4. A process as claimed in claim 1, claim 2 or claim 3 in which the amount of peroxide is chosen so that it corresponds to 0.01 - 0.1 % by weight of the total reaction mixture.
5. A process as claimed in claim 1, claim 2 or claim 3 in which the peroxide is fed into the reaction mixture in the form of a solution in acetic acid.
6. A process as claimed in claim 1, claim 2 or claim 3 in which the reaction is carried out in a reactor having an oxygen inlet and the peroxide is fed into the reactor above the oxygen inlet.
7. A process as claimed in claim 1, claim 2 or claim 3 in which the process is carried out at a pressure of from 1 to 20 atmospheres and at a temperature of from 35 to 150°C.
8. A process as claimed in claim 1, claim 2 or claim 3 in which the reaction is carried out at a pressure of from 1 to 2 atmospheres and at a temperature of from 50 to 70°C.
9. A process as claimed in claim 1, claim 2 or claim 3 in which the catalyst is selected from the group of manganese compounds, cobalt compounds, nickel compounds or mixtures thereof.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19762658043 DE2658043B2 (en) | 1976-12-22 | 1976-12-22 | Process for the production of acetic acid |
| DEP2658043.8 | 1976-12-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1107758A true CA1107758A (en) | 1981-08-25 |
Family
ID=5996181
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA293,780A Expired CA1107758A (en) | 1976-12-22 | 1977-12-22 | Process for the manufacture of acetic acid |
Country Status (11)
| Country | Link |
|---|---|
| JP (1) | JPS5379814A (en) |
| BE (1) | BE862177A (en) |
| BR (1) | BR7708545A (en) |
| CA (1) | CA1107758A (en) |
| CH (1) | CH630600A5 (en) |
| DE (1) | DE2658043B2 (en) |
| ES (1) | ES465131A1 (en) |
| FR (1) | FR2375183A1 (en) |
| GB (1) | GB1598314A (en) |
| IT (1) | IT1089981B (en) |
| NL (1) | NL7713977A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3628664A1 (en) * | 1986-08-23 | 1988-03-03 | Degussa | METHOD FOR PRODUCING 1,12-DODECANDEIAEUR II |
| DE3628662A1 (en) * | 1986-08-23 | 1988-03-03 | Degussa | METHOD FOR PRODUCING 1,12-DODECANDEIAEUR I |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR762273A (en) * | 1932-10-11 | 1934-04-09 | Fur Stickstoffduenger Ag | Process for preparing acetic acid from acetaldehyde |
| GB963430A (en) * | 1961-03-17 | 1964-07-08 | Ici Ltd | Improvements in and relating to the production of olefine oxides and carboxylic acids |
| NL289331A (en) * | 1962-02-23 | |||
| FR1367771A (en) * | 1962-07-02 | 1964-07-24 | Ici Ltd | Improved process for producing organic compounds containing oxygen |
| FR1419669A (en) * | 1963-08-19 | 1965-12-03 | Ici Ltd | Production of oxygenated organic compounds |
| CH375334A (en) * | 1963-09-19 | 1964-02-29 | Lonza Ag | Procedure for starting the oxidation of acetaldehyde |
| FR1482723A (en) * | 1965-06-09 | 1967-05-26 | Ici Ltd | Production of olefin oxides and organic acids |
| DE2520976C2 (en) * | 1975-05-10 | 1976-09-09 | Huels Chemische Werke Ag | PROCESS FOR THE PRODUCTION OF ACETIC ACID |
-
1976
- 1976-12-22 DE DE19762658043 patent/DE2658043B2/en not_active Ceased
-
1977
- 1977-12-16 NL NL7713977A patent/NL7713977A/en not_active Application Discontinuation
- 1977-12-16 ES ES465131A patent/ES465131A1/en not_active Expired
- 1977-12-19 CH CH1557677A patent/CH630600A5/en not_active IP Right Cessation
- 1977-12-20 IT IT3098277A patent/IT1089981B/en active
- 1977-12-21 BR BR7708545A patent/BR7708545A/en unknown
- 1977-12-21 JP JP15304677A patent/JPS5379814A/en active Pending
- 1977-12-22 CA CA293,780A patent/CA1107758A/en not_active Expired
- 1977-12-22 GB GB5348277A patent/GB1598314A/en not_active Expired
- 1977-12-22 FR FR7738776A patent/FR2375183A1/en active Pending
- 1977-12-22 BE BE183733A patent/BE862177A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| IT1089981B (en) | 1985-06-18 |
| NL7713977A (en) | 1978-06-26 |
| FR2375183A1 (en) | 1978-07-21 |
| DE2658043A1 (en) | 1978-06-29 |
| ES465131A1 (en) | 1978-10-01 |
| BR7708545A (en) | 1978-08-08 |
| DE2658043B2 (en) | 1979-08-16 |
| CH630600A5 (en) | 1982-06-30 |
| GB1598314A (en) | 1981-09-16 |
| JPS5379814A (en) | 1978-07-14 |
| BE862177A (en) | 1978-06-22 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |