JPH0772204B2 - Polymerization inhibitor for vinyl compound and method for preventing polymerization - Google Patents

Description

Description: FIELD OF THE INVENTION This invention relates to the polymerization of vinyl compounds.
The present invention relates to an inhibitor and a polymerization prevention method. Vinyl compounds are generally exposed to light or heat.
It has the property of being easily polymerized. Therefore, conventionally, vinyl
Place vinyl compounds to prevent polymerization of the compound
Depending on the conditions, various polymerization inhibitors may be used alone or
Are used in combination of plural kinds. In the following, among the vinyl compounds, particularly polymerized
Easy (meth) acrylic acid (in this specification, acrylic acid
If you want to mention something common to both acid and methacrylic acid,
These acids are collectively referred to as "(meth) acrylic acid". ) As an example
An explanation will be given in detail. Conventionally made (meth) acrylic acid
As a method of manufacturing, for example, propylene and / or
Or acrylic acid by catalytic gas phase oxidation reaction of acrolein
For the production of isobutylene and / or methacrolein
Methacrylic acid is produced by catalytic vapor-phase oxidation of rhein.
Method, etc. are often used. With these methods,
The reaction product gas obtained by the catalytic gas phase oxidation reaction is cooled and cooled with water.
Collects and contains by-products such as acetic acid and aldehydes
After obtaining an aqueous solution of (meth) acrylic acid, from this aqueous solution
Combine (meth) acrylic acid with processes such as distillation and solvent extraction
They are separated and purified by combining them.
Method for producing (meth) acrylic acid by catalytic vapor phase oxidation reaction
In the method, (meth) acrylic acid is separated and concentrated by distillation,
It includes steps such as purification. In addition,
As a method for producing acrylic acid, the Reppe method is used.
A method for producing acrylic acid or the acetone cyanohydrin method
A method for producing methacrylic acid by the method is also known. This
Even in these manufacturing methods, the (meth) acrylate is obtained by distillation.
It includes the steps of separating, concentrating and purifying the acid. (Meth) acrylic acid is not exposed to light or heat.
It always has the property of being easily polymerized. Therefore, in particular,
In high temperature processing such as a distillation process,
(A) The polymerizability of acrylic acid becomes extremely large. According to
In this way, (meth) acrylic acid with high polymerizability is processed.
In the case of industrial production, the polymerization of these acids in the distillation process
It is extremely important to prevent
Is an important item, especially when treating these acids under high temperature.
To establish effective polymerization prevention technology in the distillation process
Operates the process continuously and stably for a long period of time
This is an essential item above. According to the findings of the present invention
For example, of the above-mentioned distillation steps, dehydration step (water separation step)
Polymerization occurs most often, which involves distillation columns
It is the main factor that hinders continuous operation of manufacturing equipment. The (meth) acrylic acid was separated using a distillation column.
When subjected to operations such as separation, concentration, and purification, these acids are
The area where the polymer is likely to combine to form a polymer is behind the tray
Inside the bell, behind the downcomer, inside the tower, etc.
A place where it is hard to get wet with sea urchin, or a metal fitting for mounting the tray
Liquid such as (bolts, nuts) and packing parts
Most of the areas tend to be fragile. The polymer is
It is difficult to dissolve in acrylic acid, water, and ordinary organic solvents.
Once it is formed in the tower, it becomes the core of its polymerization.
And finally the tower was blocked by it
However, it will be impossible to continue operating the manufacturing equipment. Moreover, this
These accumulated polymers are very difficult to remove.
U Conventionally, when producing (meth) acrylic acid
Prevent the polymerization of (meth) acrylic acid in the distillation process
As a countermeasure, a method of distilling in the presence of a polymerization inhibitor is recommended.
Has been taken. As such a polymerization inhibitor, Hyde
Roquinone, metoquinone (p-methoxyphenol), black
Resol, phenol, t-butylcatechol, diphe
Nylamine, phenothiazine, and methylene blue?
At least one compound selected from the group consisting of:
Copper dimethyldithiocarbamate, diethyldithiocarba
Made of copper minate and copper dibutyldithiocarbamate
At least one dithiocarbami selected from the group
Polymerization inhibitor (A) consisting of copper acid salt and molecular oxygen
Known (for acrylic acid, Japanese Patent Application Laid-Open No. 49
-85016, refer to Japan for methacrylic acid
(See Japanese Patent Publication No. 57-61015). In addition, (
Other than the above polymerization inhibitors for acrylic acid, acetic acid may be used.
Polymerization inhibitor consisting of manganese salt such as manganese (B-
1), manganese salts such as manganese acetate and hydroquinone
And / or a polymerization inhibitor (B-
2), from manganese salts such as manganese acetate and molecular oxygen
Polymerization inhibitor (B-3), manganese such as manganese acetate
Molecule with salt and hydroquinone and / or metoquinone
A polymerization inhibitor (B-4) consisting of oxygen is known.
(See Japanese Patent Laid-Open No. 51-98211.
See). [0007] However, the subsequent inspection
In the discussion, the known polymerization inhibitors (A) and (B-
1) to (B-4) have the following problems.
I understood. That is, the aforementioned Japanese Patent Laid-Open No. 49-8
No. 5016 and Japanese Patent Publication No. 57-61015
The polymerization inhibitor (A) described in the publication is used for catalytic gas phase oxidation reaction.
In the distillation process when producing (meth) acrylic acid
(Meth) acrylic acid aqueous solution azeotropic separation tower (water separation
Water, acetic acid, and alcohol during the feed composition, such as
Polymerization of (meth) acrylic acid is extremely high due to the inclusion of dehydrates
When it is likely to occur due to
Therefore, popcorn polymers and viscous polymers may be used during distillation.
Occurs, and long-term continuous operation of manufacturing equipment including distillation towers
There was a problem that I could not do it. This polymerization inhibitor
(A) also contains a corrosive copper salt.
Therefore, the distillation column is easily corroded during long-term continuous operation
There was a problem. On the other hand, the above-mentioned Japanese Patent Laid-Open No. 51-98211.
The polymerization inhibitors (B-1) to (B-4) described in Japanese Patent Publication No.
It contains low-corrosion manganese salt,
There is no problem with food. However, this polymerization inhibitor
(B-1) to (B-4) are products of (meth) acrylic acid
Although there is a sufficient polymerization prevention effect against
As in the case of the agent (A), the catalytic gas phase oxidation reaction (
In the distillation process when producing acrylic acid.
T) Like an azeotropic separation tower of an aqueous solution of acrylic acid (meth)
When acrylic acid polymerization is extremely likely to occur
Is not sufficiently effective in preventing polymerization, so it is
When a cone polymer or viscous polymer is generated,
There was a problem that the equipment could not be operated for a long period of time. Further, vinylation other than (meth) acrylic acid
Conventional polymerization inhibitor and method of polymerization prevention of compound
However, there was a problem similar to the above. In this situation
However, this invention is intended for long-term continuous operation of vinyl compound production equipment.
Business, and reduce the corrosion of the equipment
Mostly, it prevents polymerization of vinyl compound products during transportation and storage.
To provide an excellent polymerization inhibitor and a method for preventing polymerization.
And are challenges. Means for Solving the Problems
Therefore, the inventors have made various studies. As a result, polymerization prevention
Dithio, which will be described in detail later, is used as the active ingredient contained in the inhibitor.
Use of carbamic acid manganese salt or thiurams
In this way, the conventional polymerization inhibitor described above
Compared with this, the polymerization prevention effect is improved and the production equipment is operated continuously for a long time
Work is possible and the corrosion of the equipment is reduced.
Was confirmed by experiments, and the present invention was completed. Therefore, the vinyl compound according to the present invention is
Polymerization inhibitors are primarily methyl groups, ethino groups, and
Is it in the group consisting of pill, butyl, and phenyl groups?
Two identical or different hydrocarbon groups selected from
Is bonded to a nitrogen atom and is the propyl group or
Even if the butyl group is linear, it may have branching.
The minimum amount of manganese dithiocarbamate that may be present
At least one kind (hereinafter referred to simply as "dithiocarbamic acid"
Manganese salt ". ) As an active ingredient
is there. Prevention of polymerization of vinyl compound according to the present invention
The method is as follows. First, the manganese salt of dithiocarbamic acid is added.
A polymerization inhibitor containing is used (hereinafter,
This is referred to as the "first polymerization prevention method". ). This invention
Secondly, a method for preventing polymerization of a vinyl compound according to
General formula (1) (However, R ¹ , R ^Two , R ^Three And R ^Four Each independently
And either an alkyl group having 1 to 8 carbon atoms or a phenyl group
It is one kind. ) As an active ingredient of thiurams
Including vinyl compound polymerization inhibitors, manganese salts and
Of at least one compound selected from the group consisting of copper salts
To use together with a polymerization inhibitor,
(Hereinafter, this is referred to as the "second polymerization prevention method")
It ). Prevention of polymerization of vinyl compound according to the present invention
The method is not limited to that described above. That is, the inventor
Et al.
It is decided to use rubamic acid copper salt and manganese salt together.
In this way, copper dithiocarbamate, which is highly corrosive,
The amount of salt used can be reduced and the dithiocarbami
Experiment that corrosion of manufacturing equipment due to copper acid salt is suppressed
Confirmed by. Therefore, the vinyl compound associated with this
Thirdly, the third method for preventing the polymerization of a substance is copper dithiocarbamate.
And manganese salt together as a polymerization inhibitor
It is also possible that
3 method for preventing polymerization ”. ). The first weight of this invention
In the prevention method, dithiocarbamate
Even if a polymerization inhibitor containing only gangan salts is used,
Anti-staining effect is obtained, but if necessary, copper salt and
Manganese salts other than manganese thiocarbamate (hereinafter,
This is simply referred to as "other manganese salt". ) Tono
If at least one of these is used as a polymerization inhibitor
Well, in that case, even better polymerization inhibitory effect can be obtained.
It In the second method for preventing polymerization of the present invention,
In addition to rums, among the above-mentioned manganese and copper salts
To use at least one of them as a polymerization inhibitor
An excellent effect of preventing polymerization can be obtained. First Polymerization of this Invention
Other man used as necessary in prevention method
Cancer salts include any of organic acid salts and inorganic acid salts.
It may be any, but is not particularly limited, for example,
Organic acid salts include manganese formate, manganese acetate,
Saturated or unsaturated having 1 to 8 carbon atoms such as manganese tannate
Manganese salts of carboxylic acids and manganese naphthenates
Other carboxylic acid manganese salts and the like, and inorganic acid salts
Examples thereof include potassium permanganate and the like. Second and third methods for preventing polymerization of the present invention
The manganese salt used in is not particularly limited.
However, for example, the manga dithiocarbamate mentioned above
And other manganese salts. Of this invention
The thiurams used in the second polymerization prevention method
As a specific example, tetramethylthiuramdis
Rufide, tetraethylthiuram disulfide, tetra
Propyl thiuram disulfide, tetrabutyl thiuram
Disulfide, tetraoctyl thiuram disulfide,
Tetraphenyl thiuram disulfide and the like can be mentioned. The first and second methods for preventing polymerization of the present invention
In particular, the copper salt used as necessary in
Although not specified, for example, dimethyldithiocarbamine
Acid copper, diethyldithiocarbamate copper, dipropyldithio
Copper ocarbamate, copper dibutyldithiocarbamate, di
Dithiocarbamic acids such as phenyldithiocarbamic acid copper
In addition to copper salts, copper acetate, copper octanoate, etc.
Examples thereof include copper salts of saturated or unsaturated carboxylic acids.
The manganese salt and copper salt described above are each
Or, a plurality of types are used together. The first polymerization method, the second polymerization method and the
In the polymerization prevention method of 3, each of the
In addition to the above polymerization inhibitors used alone or in combination,
Roquinone, metoquinone (p-methoxyphenol), black
Resol, phenol, t-butylcatechol, diphe
From Nylamine, Phenothiazine and Methylene Blue
Combined use of benzene compounds and molecular oxygen selected from the group
By doing so, due to the synergistic effect of these polymerization inhibitors,
Therefore, compared with the conventional polymerization prevention method mentioned above, the polymerization prevention effect
Further improved, enabling long-term continuous operation of manufacturing equipment
It Among the above benzene compounds, especially hydroquino
The use of quinone and / or methoquinone is preferred. From this
Prevent polymerization with a bright polymerization inhibitor and polymerization prevention method.
The vinyl compound that can be used is not particularly limited.
There are not, for example, other than (meth) acrylic acid, acrylic
Acid ester, methacrylic acid ester, acrylonitrile
And styrene. Polymerization inhibitor and polymerization prevention method of the present invention
The applicable range of is not particularly limited. For example, vinylation
The reactor, distillation column, condensing column, or
It can be applied to the storage tank of the produced vinyl compound. Specifically
Is, for example, a (meth) acrylate by a catalytic gas phase oxidation reaction.
To explain the case of producing acid, the (meth) activator
Fractionation tower of phosphoric acid, separation of (meth) acrylic acid and solvent
Tower, separation tower for (meth) acrylic acid and light components such as acetic acid.
Which distillation process, light weight such as acrolein and methacrolein
In various processes including distillation operation such as stripper of quality
And coexist the polymerization inhibitor with (meth) acrylic acid.
Effectively applied by. In the polymerization prevention method of the present invention, each weight is usually
Anti-fouling component added to vinyl compound or its solution
There is. The addition method is not particularly limited. For example,
Manganese dithiocarbamate or thiurams are
It is a solid or powder because it is easily soluble in nil compounds.
It may be added directly in the form of
You may add in the form of the solution melt | dissolved in the agent. Also other heavy
As for the anti-seize component, depending on the type, it may be solid or
It may be added directly in the form of powder or the like.
You may add in the form of the solution melt | dissolved in the organic solvent. In addition,
For the molecular oxygen used as needed, which will be described later,
For example, by air bubbling method, etc.
May be mixed directly into the solution, or other heavy
Vinyl compound or its compound dissolved in a solution of
It may be indirectly mixed in the solution. Regarding the timing of addition of each polymerization inhibiting component,
It is not limited to the above, and is added separately to the vinyl compound or its solution.
May be added, or at the same time, for example, one
It may be added in the form of a solution. Specifically, for example,
In the distillation step during the production of (meth) acrylic acid,
Polymerization preventing components other than child oxygen are (meth) acrylic acid,
And organics used in the production process of these acids
Since it is relatively soluble in the solvent, it is
Can be introduced into the process. Also, molecular oxygen
Is the bottom of the distillation or separation column and / or the reboiler
Are sent in gaseous form. The first or second vinyl compound according to the present invention
Is the amount of polymerization inhibitor used in the second polymerization prevention method.
In general, the composition of the polymerization inhibitor (combined weight
The type of anti-prevention agent), operating conditions, etc.
There is no limitation. For example, manga dithiocarbamate
When the vinyl salt is used alone, the amount added should be
10 to 50 ppm (weight basis) with respect to the amount of evaporated vapor of the product
Is preferred. In addition, mandithiocarbamate
In addition to cancer salt or thiurams (A), manganese salt
(In the case of the first polymerization prevention method, dithiocarbamate
Manganese salt other than gangan salt) or copper salt (B)
When adding, vinyl-add the total amount (A + B)
20 to 100 ppm (weight basis)
Quasi) is preferred. Furthermore, dithiocarbamic acid
In addition to manganese salts or thiurams (A), manganese
Salt (in the case of the first polymerization inhibiting method, dithiocarbamic acid
Manganese salt other than manganese salt) or copper salt (B)
Benzene compounds such as idroquinone or metquinone
When (C) is also used, the total addition amount (A + B +
C) in an amount of 20 to 50 relative to the vaporized vapor amount of the vinyl compound.
It is preferably 0 ppm (weight basis). Also this
The presence of molecular oxygen when carrying out the polymerization inhibition method of the invention.
If done below, the effect tends to persist. Therefore,
0.05-0.5 volume with respect to the amount of vapor of the nil compound
% Of molecular oxygen is preferably added. Used in the third polymerization inhibiting method of the present invention
Copper dithiocarbamate and manganese salt, and
In addition, hydroquinone or
Usage of benzene compounds such as toquinone and molecular oxygen
For, generally, the species of those polymerization inhibitors used
It varies depending on the type and operating conditions, and is not particularly limited,
For example, dithiocarbamic acid copper salt (x ₁ ),manganese
Salt (x _Two ) And a benzene compound (x _Three ) Total amount added
(X ₁ + X _Two + X _Three ) To the amount of vaporized vinyl compound
On the other hand, 200 to 500 ppm (weight basis)
The amount of child oxygen is 0.
It is preferably from 05 to 0.5% by volume. Also, dithio
On the ratio of the amount of carbamic acid copper salt and manganese salt used
Is not particularly limited, but is not particularly limited in the manganese salt.
Of the gangan atom and the copper atom in the dithiocarbamic acid copper salt
The weight ratio Mn / Cu should be 1 or more and 10 or less.
Is preferable, and more preferably 2 or more and 4 or less.
Good If the weight ratio Mn / Cu is less than 1, the equipment is
When food becomes a problem and the weight ratio Mn / Cu exceeds 10.
Is because the effect of preventing polymerization tends to be insufficient.
It [Function] Manganese salt of dithiocarbamic acid as an active ingredient
Or when thiurams are included, conventional polymerization prevention
Compared with the agent, the polymerization prevention effect is further improved, and the vinyl compound
Sufficient vinyl compound polymerization even under extremely easy polymerization conditions
To prevent vinyl compounds, including distillation columns of vinyl compounds
In addition to enabling long-term continuous operation of manufacturing equipment,
Excellent polymerization prevention during transportation and storage of nil compound products
Be effective. In addition, the manganese dithiocarbamate
Salts and thiurams are less corrosive.
Therefore, the corrosion of the manufacturing equipment is reduced. Also, dithiocarbamic acid copper salt and manga
Even if it is used together with a salt as a polymerization inhibitor,
Due to the synergistic effect of those polymerization inhibitors, as described above,
In order to prevent polymerization of vinyl compounds sufficiently, vinyl compounds
It enables long-term continuous operation of manufacturing equipment of
Excellent polymerization inhibitory effect even during transportation and storage
Exert fruit. Also, the manganese salt is dithiocarbamic acid.
Reduces the corrosion of the above equipment by reducing the corrosiveness of copper salts
It EXAMPLES Specific examples of the present invention will be shown below together with comparative examples.
However, the present invention is not limited to the following examples. In addition,
The unit ppm in the following examples and comparative examples is
Based on quantity. -Example 1.1- Purified acrylic acid (vinyl compound) with a polymerization inhibitor
Manganese dibutyldithiocarbamate to acrylic acid
1ppm added to prepare an acrylic acid solution
It was Next, the molecular oxygen exerts a polymerization inhibiting effect.
Manganese dibutyldithiocarbamate only, excluding effects
This acrylic acid solution was used to see the effect of preventing polymerization due to
Transfer 5 ml to a 20 ml test tube and use nitrogen gas bubbling.
By applying a flow rate of 30 ml / min for 1 minute.
The dissolved oxygen in the acid solution was removed and the mouth of the test tube was sealed.
Immerse this test tube in an oil bath maintained at 130 ℃
Then, the polymerization initiation time of acrylic acid was measured. However,
The start time is the test after immersing the test tube in the oil bath.
It was the time until the sealed liquid in the tube became cloudy. The result is below
The results are shown in Table 1. -Examples 1.2 to 1.16 and comparative examples
1.1 to 1.23-In Example 1.1, type of vinyl compound and prevention of polymerization
Type and amount of agent, heating temperature, polymerization initiator (AIB
N: azoisobutyronitrile) with or without addition of the following Table 1
Same as Example 1.1, except modified as described in 8.
In this way, the polymerization initiation time of the vinyl compound was measured. So
The results are shown in Tables 1 to 8 below. In Tables 1 to 8 below, the "molecular acid" of each example is shown.
“None” in the column “whether or not the element is used together” is the same as in Example 1.1
Similarly, the solution of the vinyl compound is filled with nitrogen gas at 30 ml / min.
By bubbling at the flow rate for 1 minute, the polymerization prevention effect
It was shown that the effect of molecular oxygen on fruits was eliminated.
"Yes" in the column indicates 30 ml / air instead of nitrogen gas.
By bubbling for 1 minute at a flow rate of
It shows that oxygen was used together as a polymerization inhibitor. [Table 1] [Table 2] [Table 3] [Table 4] [Table 5] [Table 6] [Table 7] [Table 8] From the results shown in the above 1 to 8, the following 1.
(A) -1. (D) was confirmed. 1. (A) Contains manganese dibutyldithiocarbamate
The polymerization inhibitor according to the example is dibutyldithiocarbamine.
Compared with the polymerization inhibitor according to the comparative example containing no manganese acid
In all, the effect of preventing polymerization of various vinyl compounds is high. 1. (B) Manganese dibutyldithiocarbamate alone
Even when used in, it has a sufficient effect of preventing polymerization. 1. (C) Dibutyldithiocarbamate
In addition to gangan, of hydroquinone and molecular oxygen
If one of them is used together, the effect of preventing polymerization will be further enhanced.
It 1. (D) In addition to manganese dibutyldithiocarbamate
Then, when both hydroquinone and molecular oxygen are used together,
Maximum polymerization prevention effect. -Example 1.17- A 50-step stainless steel sieve tray has a step interval of 147 mm.
With a distilling pipe in the upper part and a raw material supply pipe in the center.
Use the equipped distillation column with an inner diameter of 105 mm, and use acrylic acid water.
A continuous azeotropic separation of the solution was carried out. The polymerization inhibitor used was dibutyldithio.
Manganese carbamate, hydroquinone and molecular acids
It was plain. Manganese dibutyldithiocarbamate and
Both hydroquinone and
Introduced into the tower from two locations, and described later from the feed stage
After adding a predetermined amount to the feedstock and dissolving it,
Introduced into the tower in the form of a predetermined amount dissolved in the reflux liquid described in
did. A predetermined amount of molecular oxygen was supplied to the bottom of the column. Each polymerization
The amount of the prevention component used is based on the amount of acrylic acid vaporized vapor.
20 ppm of manganese dibutyldithiocarbamate,
Idroquinone was 200 ppm. Also, input oxygen
The amount is 0.3% by volume based on the amount of vaporized acrylic acid vapor.
It was The effect of preventing polymerization is due to the pressure loss and flooding in the tower.
It was confirmed by the wing or the dismantling inspection of the tower. Feedstock
As obtained by catalytic gas phase oxidation of propylene
In addition, water containing 30% by weight and acetic acid 2.5% by weight
Methyl isobutyl ketone was used as the reflux liquid with phosphoric acid.
Used, tower top temperature 46 ° C, tower bottom temperature 97 ° C, tower top pressure 112
mmHg, supply liquid volume 10.56 liter / hr, reflux ratio
Distilled under the condition of (R / D) = 0.92 (mol basis)
It was The composition of the liquid extracted from the bottom of the column in the steady state is
Acrylic acid 97.0% by weight, acetic acid 0.5% by weight, others
It was 2.5% by weight. The reflux liquid recycles the distillate oil phase.
I used it. Under this condition, it was operated continuously for about 14 days.
In the distillation column, a stable condition was always obtained and the operation was stopped.
In the result of the inspection of
I couldn't do it. In addition, the S that was previously installed in the tower
Corrosion of US316 test pieces (manufactured by Nippon Yakin Kogyo Co., Ltd.)
After the completion, it was not observed at all and the mdd value was 0. here
The mdd value represents the weight loss of the test piece,
It is a measure of the presence or absence of corrosion. The unit is mg /
(Dm ^Two * Day), depending on the size of the value,
,, according to the following examples and ratios
The same applies to the mdd value in the comparative example). When mdd <1 :: Sufficiently usable. When 1 ≦ mdd <5: Withstand use. When mdd ≧ 5: Somewhat difficult to use. -Example 1.18- A 50-step stainless steel sieve tray has a step interval of 147 mm.
With a distilling pipe in the upper part and a raw material supply pipe in the center.
Using the equipped distillation column with an inner diameter of 105 mm,
Continuous operation of azeotropic separation of the aqueous solution was performed. The polymerization inhibitor used was dimethyldithio.
Manganese carbamate, hydroquinone and molecular acids
It was plain. Manganese dimethyldithiocarbamate and
Both hydroquinone and
Introduced into the tower from two locations, and described later from the feed stage
After adding a predetermined amount to the feedstock and dissolving it,
Introduced into the tower in the form of a predetermined amount dissolved in the reflux liquid described in
did. A predetermined amount of molecular oxygen was supplied to the bottom of the column. Each polymerization
The amount of the preventive component used is based on the amount of vaporized methacrylic acid vapor.
20 pp of manganese dimethyldithiocarbamate
m and hydroquinone were 200 ppm. Also, throw
The amount of oxygen input is 0.3 volume with respect to the amount of vaporized methacrylic acid vapor.
The amount was set to%. The effect of preventing polymerization is due to the pressure loss and flooding in the tower.
It was confirmed by the wing or the dismantling inspection of the tower. Feedstock
As obtained by catalytic gas phase participation reaction of isobutylene
37% by weight of methacrylic acid and 9.05 weight of acetic acid
%, And 50% by weight of water in methacrylic acid aqueous solution
From n-heptane at an extraction ratio of 1.3
The obtained n-heptane was 76.4% by weight, methacrylic
N containing 21.8% by weight of acid and 1.3% by weight of acetic acid
-Heptane phase was used. As the reflux liquid, distilled n-
Heptane was used. Tower top temperature 42 ° C, Tower bottom temperature 122
° C, tower top pressure 105 mmHg, reflux ratio = 1.0 (weight basis
Distilled under the conditions of (quasi). The composition of the liquid extracted from the bottom of the column in the steady state is
Methacrylic acid was 99.7% by weight. About 1 under these conditions
After operating continuously for 4 days, a stable condition was always obtained.
After the operation was stopped, the result of inspecting the inside of the distillation column was
However, generation of a polymer was not observed at all. In addition, the S installed in advance in the tower
Corrosion of US316 test pieces (manufactured by Nippon Yakin Kogyo Co., Ltd.)
After the completion, it was not observed at all and the mdd value was 0. -Example 1.19-In Example 1.17, manganese dithiocarbamate is used.
Alternative to manganese dibutyldithiocarbamate as salt
To use manganese diethyldithiocarbamate for
Under the same apparatus and conditions as in Example 1.17 except that
The acrylic acid aqueous solution was distilled. Continuous operation for about 14 days, always stable
After the operation was stopped, the inside of the distillation column was inspected.
In the results, no polymer was found to occur.
It was In addition, SUS31 installed in the tower in advance
Corrosion of 6 test pieces (manufactured by Nippon Yakin Kogyo Co., Ltd.)
It was not observed at all, and the mdd value was 0. -Example 1.20-In Example 1.17, manganese dithiocarbamate
Transformation of manganese dibutyldithiocarbamate as a salt
To use manganese diphenyldithiocarbamate for
The same apparatus and conditions as in Example 1.17 except that
Then, the acrylic acid aqueous solution was distilled. Continuous operation for about 14 days, always stable
After the operation was stopped, the inside of the distillation column was inspected.
In the results, no polymer was found to occur.
It was In addition, SUS31 installed in the tower in advance
Corrosion of 6 test pieces (manufactured by Nippon Yakin Kogyo Co., Ltd.)
It was not observed at all, and the mdd value was 0. -Example 1.21-In Example 1.17, with respect to acrylic acid evaporation vapor amount
To prevent polymerization of 10 ppm copper dibutyldithiocarbamate
A device similar to that of Example 1.17 except that it was added as a stopping component.
The aqueous acrylic acid solution was distilled under various conditions and conditions. Continuous operation for about 14 days, always stable
After the operation was stopped, the inside of the distillation column was inspected.
In the results, no polymer was found to occur.
It was In addition, SUS31 installed in the tower in advance
Corrosion of 6 test pieces (manufactured by Nippon Yakin Kogyo Co., Ltd.)
It was not observed at all, and the mdd value was 0. -Example 1.22-Using an evaporation kettle with an inner diameter of 105 mm, a series of acrylic acid solutions was used.
The continuous distillation operation was performed. [0052] The polymerization inhibitor used was dibutyldithio
Manganese carbamate, metoquinone, and molecular oxygen
Met. Manganese dibutyldithiocarbamate and
Metquinone was used in the specified amount in the feedstock described later.
2 of the feed and condenser in the form of adding and dissolving
It was introduced from the place into the pot. A certain amount of molecular oxygen at the bottom of the kettle
Supplied. The amount of each polymerization inhibitor used depends on the amount of acrylic vapor
Manganese dibutyldithiocarbamate is
It was 12 ppm and metquinone was 120 ppm. Well
Further, the amount of input oxygen is 0.
It was 3% by volume. The effect of preventing polymerization depends on the pressure loss or dismantling in the tower.
Confirmed by inspection. As a feedstock, hydrazine
99.0 wt% crude acrylic containing 500 ppm of
Conditions using an acid and a tower top temperature of 63 ° C. and an operating pressure of 35 mmHg
Distilled under. The distillate composition in steady state is
The acid content was 99.9% by weight. Under these conditions for about 14 days
After continuous operation, a stable condition was always obtained and the operation was stopped.
After stopping, the results of the inspection inside the distillation pot were
No occurrence was observed. In addition, S which is installed in the tower in advance
Corrosion of US316 test pieces (manufactured by Nippon Yakin Kogyo Co., Ltd.)
After the completion, it was not observed at all and the mdd value was 0. -Comparative Example 1.24-in Example 1.17, dibutyldithiocarbamic acid
Copper dibutyldithiocarbamate instead of manganese
Use 20ppm for the amount of evaporated vapor of acrylic acid
The same apparatus and conditions as in Example 1.17 except that
Then, the acrylic acid aqueous solution was distilled. After continuous operation for about 14 days, the pot gradually
Shell pressure increased. After stopping the operation, check the inside of the distillation column.
As a result, it was confirmed that popcorn polymer was generated in the pot.
Was given. In addition, SUS installed in the tower in advance
The 316 test piece (manufactured by Nippon Yakin Kogyo Co., Ltd.) is corroded, and m
The dd value was 5.0. From this result, dithiocarbami
Use dithiocarbamic acid copper salt instead of manganese acid salt
If it is present, the effect of preventing polymerization will decrease and the equipment will not be corroded.
It was confirmed to be the subject. Comparative Example 1.25-In Example 1.17, dibutyldithiocarbamic acid
Manganese acetate instead of manganese, evaporation of acrylic acid
Implemented except that the amount of steam used is 20 ppm
Acrylic acid water soluble under the same equipment and conditions as in Example 1.17.
The liquid was distilled. As a result, two days after the start of operation, the pressure in the tower was reduced.
Loss was recognized and it was difficult to continue operation.
When the operation was stopped and the dismantling inspection was performed, the
Polymer formation was observed. From this result, dithiocarba
When using a manganese salt other than manganese minate,
It was confirmed that the polymerization-preventing effect of was decreased. Example 2.1-Purified acrylic acid was added to tetrabutyl as a polymerization inhibitor.
Thiuram disulfide (hereinafter abbreviated as TBTDS) and
And manganese acetate to acrylic acid at 2 ppm and
Prepare an acrylic acid solution containing 1 ppm and 1 ppm of
Transfer 5 ml of the phosphoric acid solution to a 20 ml test tube and add 3 air.
Bubble 1 minute at a flow rate of 0 ml / min to dissolve acrylic acid.
After dissolving oxygen in the liquid, the mouth of the test tube was sealed. this
Immerse the test tube in an oil bath maintained at 130 ° C and
The polymerization initiation time of acrylic acid was measured. However, initiation of polymerization
For the time, immerse the test tube in the oil bath and then
It was the time until the sealing liquid became cloudy. The results obtained are as follows
The results are shown in Table 9. Example 2.2-TBTDS, manganese acetate and high
Doloquinone 2ppm, 1ppm and 50ppm respectively
Acrylic acid was added in the same manner as in Example 2.1 except that the acrylic acid was added.
The polymerization initiation time was measured. The results obtained are shown in Table 9 below.
did. -Comparative Examples 2.1 to 2.3-As polymerization inhibitors, TBTDS, hydroquinone or
Example 2.1 except that 50 ppm each of methquinone was added.
In the same manner as above, the polymerization initiation time of acrylic acid was measured.
The results obtained are shown in Table 9 below. -Comparative Examples 2.4 and 2.5-Except that TBTDS was not added as a polymerization inhibitor.
Polymerization of acrylic acid as in Examples 2.1 or 2.2
The start time was measured. The results obtained are shown in Table 9 below.
It was Comparative Example 2.6 Copper dibutyldithiocarbamate as a polymerization inhibitor and
Hydroquinone was added at 1 ppm and 50 ppm respectively
Polymerization of acrylic acid was carried out in the same manner as in Example 2.1 except that
The start time was measured. The results obtained are shown in Table 9 below. Comparative Example 2.3 TBTDS and manganese acetate as polymerization inhibitors are respectively used.
2ppm and 1ppm added, nitrogen instead of air
Except bubbling to remove oxygen in the acrylic acid solution
Polymerization start time of acrylic acid in the same manner as in Example 2.1.
Was measured. The obtained results are shown in Table 10 below. Comparative Example 2.4-TBTDS, manganese acetate and ha
2ppm, 1ppm and 50pp of idroquinone respectively
m, and nitrogen is bubbled instead of air.
Similar to Example 2.1 except that oxygen in the acid solution was removed.
Then, the polymerization initiation time of acrylic acid was measured. Got
The results are shown in Table 10 below. -Comparative Examples 2.7 and 2.8-Except that TBTDS was not added as a polymerization inhibitor.
Polymerization of acrylic acid as in Example 2.3 or 2.4.
The start time was measured. The results obtained are shown in Table 10 below.
It was [Table 9] [Table 10] -Examples 2.5 to 2.8 and Comparative Example 2.
9-2.16- Methacrylic acid was used instead of acrylic acid, and the heating temperature was
Set the temperature to 160 ° C and add the type and amount of polymerization inhibitor, and
The types of gas to be bled are shown in Tables 11 to 12 below.
In the same manner as in Example 2.1 except that
The polymerization initiation time of phosphoric acid was measured. The results obtained are as follows
It shows in Tables 11-12. [Table 11] [Table 12] -Comparative Examples 2.17 to 2.26-Vinyl compound type, polymerization inhibitor type and addition amount, vinyl
The type of gas bubbling the compound solution and the heating temperature.
Examples except that the changes were made as shown in Tables 13 to 14 below.
Measure the polymerization start time of vinyl compounds in the same manner as in 2.1.
Decided However, in Comparative Examples 2.21-2.26, polymerization
In addition to the inhibitor, the amount of polymerization shown in Tables 13 to 14 below was initiated.
Agent [azoisobutyronitrile (AIB in Tables 13-14)
Abbreviated as N)]] was added. The obtained results are shown in Table 13 below.
Shown in 14. [Table 13] [Table 14] -Comparative Example 2.9- A 50-step stainless steel sieve tray has a step interval of 147 mm.
With a distilling pipe in the upper part and a raw material supply pipe in the center.
Using an internal 105 mm distillation column equipped with a polymerization inhibitor
And TBTDS, manganese acetate and hydroquinone
Using azeotropic separation of acrylic acid aqueous solution,
It was Obtained by catalytic gas phase oxidation of propylene
66.5% by weight of acrylic acid, 30% by weight of water and
Solution of acrylic acid containing 2.5% by weight of acetic acid in a distillation column.
Methyl isobutyl ketone used as an azeotropic solvent
The distillate is separated into an oil phase and an aqueous phase, and the aqueous phase is removed.
Take out and use the oil phase (methyl isobutyl ketone phase) as the reflux liquid.
Used at the top temperature of 46 ° C, bottom temperature of 97 ° C, top pressure of 11
2 mmHg, supply liquid volume 10.56 l / hr, reflux
Distilled under the condition of ratio (R / D) = 0.92 (mono standard)
It was During this time, manganese acetate was added and dissolved in the distillate water phase.
TBTDS and hydroquinone are added to the reflux liquid as
Introduced into the tower from the top of the tower, both added and dissolved
It was Further, molecular oxygen was supplied to the bottom of the column. Each polymerization prevention
The amount of the stopper used is TB with respect to the amount of vaporized acrylic acid vapor.
TDS 18ppm, manganese acetate 11ppm, high
Doloquinone was 200 ppm. Also, the amount of oxygen input
Is 0.31% by volume with respect to the amount of vaporized acrylic acid vapor.
It was. After continuous operation for about 14 days under these conditions, inside the tower
There is no pressure loss, flooding, etc.
The state was obtained. After the operation was stopped, the inside of the distillation column was inspected.
In the results, no polymer was found to occur.
It was In addition, in this experiment, the material of the device was corroded.
In order to see the food, the SUS316 test piece was previously placed in the tower.
(Made by Nippon Metal Industry Co., Ltd.) was installed. After the operation is stopped,
When this test piece was taken out, no corrosion was found.
No, the mdd value was 0. -Comparative Example 2.10-50-stainless steel sieve trays with a step interval of 147 mm.
With a distilling pipe in the upper part and a raw material supply pipe in the center.
Using a distillation column with an inner diameter of 105 mm equipped with a polymerization inhibitor
And TBTDS, manganese acetate and hydroquinone
A continuous distillation operation of methacrylic acid was carried out. Isobutyle was used as a raw material to be supplied to the distillation column.
Gas obtained by collecting the gas produced by the catalytic gas-phase oxidation reaction of hydrogen.
Obtained by extraction from aqueous acrylic acid with n-heptane
N-heptane 76.4% by weight, methacrylic acid 21.
N-heptane phase containing 8% by weight and 1.3% by weight acetic acid
Was used. This raw material is supplied from the raw material supply pipe to the middle stage of the distillation column.
Supply, tower top temperature 42 ° C, tower bottom temperature 122 ° C, tower top pressure 10
Steamed under the conditions of 5 mmHg and reflux ratio = 1.0 (weight basis)
I stayed. During this time, manganese acetate was added and dissolved in water.
In addition, TBTDS and hydroquinone are added to the reflux liquid.
-In the form of being dissolved, each was introduced into the tower from the top.
Further, in the molecular state, it was supplied to the bottom of the tower. Each polymerization inhibitor
The amount used of TBT is
DS is 18ppm, manganese acetate is 11ppm, hide
Roquinone was 200 ppm. Also, the amount of oxygen input
Is 0.3% by volume based on the amount of methacrylic acid vaporized vapor.
It was. Composition of liquid extracted from the bottom of the column in steady state
Was 99.7% by weight of methacrylic acid. In this condition
After continuous operation for about 14 days, pressure loss and
There are no abnormalities such as dings, and a stable condition is always obtained.
It was After the operation was stopped, the result of inspecting the inside of the distillation column was
However, generation of a polymer was not observed at all. In addition, during this experiment,
In order to see the food, the SUS316 test piece was previously placed in the tower.
(Made by Nippon Metal Industry Co., Ltd.) was installed. After the operation is stopped,
When this test piece was taken out, no corrosion was found.
No, the mdd value was 0. -Comparative Example 2.11-Using an evaporation kettle having an inner diameter of 105 mm, T as a polymerization inhibitor
Using BTDS, manganese acetate and metoquinone,
Continuous distillation operation of the acrylic acid solution was performed. As a feedstock, 500 pp of hydrazine
m using a crude acrylic acid having a purity of 99.0 wt.
Distilled under conditions of a top temperature of 63 ° C and an operating pressure of 35 mmHg.
It was During this period, TBTD
S11ppm, manganese acetate 7ppm, metoquinone 12
A form in which an amount equivalent to 0 ppm is added to and dissolved in the feedstock
It was supplied to the distillation column together with the raw materials. Also, from the bottom
Equivalent to 0.3% by volume of acrylic acid vapor
Molecular oxygen was supplied. Distillate composition in steady state
Was 99.9% by weight of acrylic acid. Under these conditions, continuous operation for about 14 days
No abnormalities such as pressure loss in the tower, flooding, etc.
A stable state was obtained. After the operation is stopped, the point in the distillation column
In the results of the inspection, no polymer was found to be generated.
There wasn't. In addition, the SU installed in the tower in advance
Corrosion of S316 test pieces (manufactured by Nippon Yakin Kogyo Co., Ltd.)
After completion, it was not observed at all and the mdd value was 0. -Example 2.12-In Example 2.9, copper acetate was used instead of manganese acetate.
The same apparatus and conditions as in Example 2.9 except that
Then, the acrylic acid aqueous solution was distilled. Continuous luck for about 14 days
When rolled, abnormalities such as pressure loss and flooding in the tower
Nonetheless, a stable condition was always obtained. However,
SUS316 test piece installed in the bullying tower (Nihonji
(Made by Kinkogyo Co., Ltd.) showed a mdd value of 5.0
It was From this result, the combination of TBTDS and copper acetate was
Corrosion of equipment compared to using BTDS and manganese acetate together
It was confirmed that the size was rather large. From the above results, the following 2. (A) to 2.
(E) was confirmed. 2. (A): a thiuram represented by the general formula (1)
Even when used alone, it has a polymerization inhibiting effect. 2. (B): In the thiurams represented by the general formula (1)
In addition, when manganese salt or copper salt is used together, polymerization is prevented.
The effect is further enhanced. 2. (C): 2. In addition to the configuration of (b)
Hydroquinone and / or metquinone together
Then, the polymerization prevention effect is further enhanced. 2. (D): a thiuram represented by the general formula (1)
In the examples used, hydroquinone was used instead.
Compared to comparative examples using
Highly effective in preventing polymerization. 2. (E): represented by the general formula (1)
When using thiurams and manganese salts together,
In addition to the anti-polymerization effect, there is little corrosion of the device and the vinyl compound
Enables long-term continuous operation of product manufacturing equipment. -Example 3.1-A 50-step stainless steel sieve tray has a step interval of 147 mm.
With a distilling pipe in the upper part and a raw material supply pipe in the center.
Use the equipped distillation column with an inner diameter of 105 mm, and use acrylic acid water.
A continuous azeotropic separation of the solution was carried out. The polymerization inhibitor system used was manganese acetate,
Copper dibutyldithiocarbamate, hydroquinone and
It was molecular oxygen. Copper dibutyldithiocarbamate
Is a solution prepared by adding and dissolving a specified amount to the reflux liquid described later.
Introduced into the tower. Manganese acetate is used in the feed stage and
And from the top of the tower to the inside of the tower, and from the feed stage,
After adding a predetermined amount to the feedstock described later and dissolving it,
And the like were introduced into the tower in a form in which a predetermined amount was added and dissolved in water.
Hydroquinone comes from two places, the feed stage and the top of the tower.
Introduced into the tower, and from the feed stage, feed materials described later
In the form of a predetermined amount added and dissolved in the
A predetermined amount of the solution was added and dissolved and introduced into the tower. molecule
A certain amount of gaseous oxygen was supplied to the bottom of the column. Use of each polymerization inhibitor
The dosage is manganese acetate based on the amount of vaporized acrylic acid vapor.
Is 30 ppm, copper dibutyldithiocarbamate is 20 p
pm and hydroquinone were 200 ppm. At this time
The weight ratio Mn / Cu of manganese atom to copper atom of
It was 3.5. Also, the amount of oxygen input is acrylic acid evaporation
It was 0.3% by volume with respect to the amount of steam. The polymerization preventing effect is due to the pressure loss and flooding in the tower.
It was confirmed by the wing or the dismantling inspection of the tower. Feedstock
As obtained by catalytic gas phase oxidation of propylene
In addition, water containing 30% by weight and acetic acid 2.5% by weight
Methyl isobutyl ketone was used as the reflux liquid with phosphoric acid.
Used, tower top temperature 46 ° C, tower bottom temperature 97 ° C, tower top pressure 112
mmHg, tower bottom pressure 153 mmHg, feed liquid amount 10.56
Liter / hr, reflux ratio (R / D) = 0.92 (molar group
Distilled under the conditions of (quasi). The composition of the liquid extracted from the bottom of the column in the steady state is
Acrylic acid 97.0% by weight, acetic acid 0.5% by weight, others
It was 2.5% by weight. The reflux liquid recycles the distillate oil phase.
I used it. Distillation of acetic acid in the above stationary bear
The rate was 85.2%, and this distillation experiment was conducted with 30 weight% of water.
% And 2.5% by weight of acetic acid from acrylic acid with water
The condition was such that acetic acid was also separated. Under these conditions, continuous operation was performed for about 14 days.
In the distillation column, a stable condition was always obtained and the operation was stopped.
In the result of the inspection of
I was not able to admit. Also, install it in the tower in advance.
Of SUS316 test piece (made by Nippon Yakin Kogyo Co., Ltd.)
Was not recognized at all after the operation was completed, and the mdd value was 0.
It was -Example 3.2-In Example 3.1, acrylic acid was changed to methacrylic acid.
A continuous distillation operation was performed in the same manner as in Example 3.1 except that
went. However, as a feedstock, contact with isobutylene
The methacrylic acid obtained by the tactile phase oxidation reaction was
Wt%, acetic acid 9.07 wt% and water 50 wt%
Extraction ratio from aqueous methacrylic acid solution with n-heptane
The n-heptane obtained by the extraction operation in 1.3 was
6.4 wt%, methacrylic acid 21.8 wt% and vinegar
Using an n-heptane phase containing 1.3% by weight of acid, the column top temperature
42 ℃, tower bottom temperature 122 ℃, tower top pressure 105mmHg, return
Distillation was carried out under the condition of flow ratio = 1.0 (weight basis). The composition of the liquid withdrawn at the bottom of the column in the steady state is
Methacrylic acid was 99.7% by weight. About 1 under these conditions
After operating continuously for 4 days, a stable condition was always obtained.
After the operation was stopped, the result of inspecting the inside of the distillation column was
However, generation of a polymer was not observed at all. In addition, the S that was previously installed in the tower
Corrosion of US316 test pieces (manufactured by Nippon Yakin Kogyo Co., Ltd.)
After the completion, it was not observed at all and the mdd value was 0. -Example 3.3-In Example 3.1, manganese acetate was used as the manganese salt.
Except that manganese octoate is used instead of
In the same manner as in Example 3.1, continuous distillation operation was performed.
However, the amount of manganese octoate used should be
The amount of steam generated is 60 ppm,
Polymerization ratio Mn / Cu of manganese atom to 3.5 is 3.5.
It was. Under these conditions, continuous operation was performed for about 14 days.
In the distillation column, a stable condition was always obtained and the operation was stopped.
The results of the inspection of
It was not recognized. Also, install it in the tower in advance.
Corrosion of SUS316 test pieces (made by Nippon Yakin Kogyo Co., Ltd.)
Was not recognized at all after the operation was completed, and the mdd value was 0.
It was -Example 3.4-In Example 3.1, manganese acetate was used as the manganese salt.
Since potassium permanganate is used instead of
A continuous distillation operation was performed in the same manner as in Example 3.1 except for the above.
It was However, the amount of potassium permanganate used is
30ppm with respect to the amount of vaporized acid vapor,
The weight ratio Mn / Cu of manganese atoms to atoms is 3.
It was 8. Under this condition, continuous operation was performed for about 14 days.
In the distillation column, a stable condition was always obtained and the operation was stopped.
The results of the inspection of
It was not recognized. Also, install it in the tower in advance.
Corrosion of SUS316 test pieces (made by Nippon Yakin Kogyo Co., Ltd.)
Was not recognized at all after the operation was completed, and the mdd value was 0.
It was -Example 3.5-In Example 3.1, as a dithiocarbamic acid copper salt
Dibutyldithiocarbamate instead of copper
Example 3 except that copper ocarbamate was used.
A continuous distillation operation was performed in the same manner as in 1. However,
The amount of copper tyldithiocarbamate used is acrylic acid evaporation
It is 20ppm with respect to the amount of steam, and
The weight ratio Mn / Cu of manganese atoms is 3.2.
It was Under these conditions, continuous operation was performed for about 14 days.
In the distillation column, a stable condition was always obtained and the operation was stopped.
The results of the inspection of
It was not recognized. Also, install it in the tower in advance.
Corrosion of SUS316 test pieces (made by Nippon Yakin Kogyo Co., Ltd.)
Was not recognized at all after the operation was completed, and the mdd value was 0.
It was -Example 3.6-In Example 3.1, instead of hydroquinone, meth
Same as Example 3.1 except that quinone was used.
Then, the continuous distillation operation was performed. However, the use of metquinone
Dosage is 200ppm based on the amount of vaporized acrylic acid vapor
there were. After operating continuously for about 14 days under these conditions,
A stable condition was obtained, and after the operation was stopped, the distillation column was inspected.
Even in the result of carrying out the
I couldn't do it. In addition, the S that was previously installed in the tower
Corrosion of US316 test pieces (manufactured by Nippon Yakin Kogyo Co., Ltd.)
After the completion, it was not observed at all and the mdd value was 0. -Example 3.7- In Example 3.1, only the amount of manganese acetate used was changed to 1
Increased to 00ppm, the weight ratio of manganese atom and copper atom
A device similar to Example 3.1 except that Mn / Cu was changed to 12.
The aqueous acrylic acid solution was distilled under various conditions and conditions. Steaming
Five days after the start of the distillation, the pressure loss inside the tower was slightly recognized.
Was messed up. From this result, the weight of manganese atom and copper atom
If the amount ratio Mn / Cu is too high, the effect of preventing polymerization decreases.
It was confirmed. Comparative Example 3.1-In Example 3.1, Do Not Use Manganese Acetate
Except that the same apparatus and conditions as in Example 3.1 were used.
The aqueous solution of acrylic acid was distilled. Continuous operation for about 14 days
After a while, the shell pressure of the kettle gradually increased. Operation stop
After that, as a result of inspecting the inside of the distillation column, popcorn was placed in the kettle.
Generation of polymer was observed. Also, in advance in the tower
The installed SUS316 test piece (Nihon Yakin Kogyo Co., Ltd.
Product) was corroded, and the mdd value was 5.0. this
From the results, without using manganese salt, copper dithiocarbamate
Using only salt, phenolic compounds and molecular oxygen,
The polymerization prevention effect may decrease, and equipment corrosion may become a problem.
confirmed. Comparative Example 3.2 Copper copper dibutyldithiocarbamate in Example 3.1
A device similar to that of Example 3.1 except that the above is not used.
Acrylic acid aqueous solution was distilled under the following conditions. operation
Two days after the start of the operation, pressure loss in the tower was observed, and operation was continued.
It was difficult to continue. Stop operation and dismantle inspection
As a result, formation of a viscous polymer was confirmed in the tower.
From this result, dithiocarbamic acid copper salt was not used and dithiocarbamic acid was not used.
Manganese salts other than manganese ocarbamate and phenol
The use of only ruthenium compounds and molecular oxygen prevents polymerization during distillation.
It was confirmed that the stopping effect was low. INDUSTRIAL APPLICABILITY The vinyl compound according to the present invention is prevented from polymerizing.
According to the inhibitor and polymerization prevention method, vinyl compounds are extremely
Polymerization of vinyl compounds is sufficient even under conditions where
Of vinyl compounds including distillation columns of vinyl compounds that are prevented
In addition to enabling long-term continuous operation of manufacturing equipment,
Requires less corrosion of building equipment. Also, this vinyl compound
Polymerization inhibitors and polymerization prevention methods for
It can be applied not only during manufacturing but also during transportation and storage of products.
Wear.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical indication C07C 57/075 9356-4H 67/62 9279-4H 69/54 Z 9279-4H 253/32 255 / 08 9357-4H (72) Inventor, Yoji Ajizawa, 992, Nishioki, Nishihama, Aboshi-ku, Himeji-shi, Hyogo Prefecture. 1 In Nippon Catalyst Co., Ltd., Himeji Works (72) Inventor, Masao Baba, 1, 992, Nishiki-oki, Abashi-ku, Himeji-shi, Hyogo, Ltd. Nippon Shokubai Inside Himeji Plant (56) References JP-A-54-40888 (JP, A) JP-B-60-3103 (JP, B2)

Claims (1)

Claims: 1. Two identical or different hydrocarbon groups selected from the group consisting of a methyl group, an ethyl group, a propyl group, a butyl group, and a phenyl group are bonded to a nitrogen atom. In addition, the polymerization of a vinyl compound containing, as an active ingredient, at least one manganese salt of dithiocarbamic acid which may be linear or branched in the propyl group or the butyl group. Preventive agent. 2. A method for preventing polymerization of a vinyl compound, which comprises using the polymerization inhibitor according to claim 1. 3. A compound other than manganese salt of dithiocarbamic acid.
Gangan salt, copper salt and hydroquinone, methoquinone (p
-Methoxyphenol), cresol, phenol, t
-Butylcatechol, diphenylamine, phenothiadi
Benzene selected from the group consisting of
At least one compound selected from the group consisting of
The compound is used together as a polymerization inhibitor.
2. The method for preventing polymerization of a vinyl compound according to 2. 4. The following general formula (1): (However, R ¹ , R ² , R ³ and R ⁴ are each independently
And either an alkyl group having 1 to 8 carbon atoms or a phenyl group
It is one kind. ) As an active ingredient of thiurams
Including vinyl compound polymerization inhibitors, manganese salts and
Of at least one compound selected from the group consisting of copper salts
Vinyl compound to be used together with polymerization inhibitor
Polymerization prevention method. 5. A method for preventing polymerization of a vinyl compound, wherein a copper salt of dithiocarbamic acid and a manganese salt are used together as a polymerization inhibitor. 6. A hydroquinone, a methoquinone (p-meth)
Xylphenol), cresol, phenol, t-butyl
Lucatechol, diphenylamine, phenothiazine and
And a benzene compound selected from the group consisting of methylene blue
The compound is also used as a polymerization inhibitor.
5. The method for preventing polymerization of a vinyl compound according to 5. 7. A vinyl compounds, vinyl according to any one of acrylic acid, methacrylic acid, acrylic acid esters, methacrylic acid esters, claim 2 is either selected from the group consisting of acrylonitrile and styrene to 6 A method for preventing polymerization of a compound.